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Agilent 750/89 Premium Shielded High Resolution NMR Magnet System

System Overview

Agilent Technologies

Notices© Agilent Technologies, Inc. 2012

No part of this manual may be reproduced in any form or by any means (including electronic storage and retrieval or transla-tion into a foreign language) without prior agreement and written consent fromAgilent Technologies, Inc. as governed by United States and international copyright laws.

Manual Part Number

9100381100

Edition

Revision B, October 2012

Printed in USA

Agilent Technologies, Inc.5301 Stevens Creek Boulevard Santa Clara, CA 95051 USA

Warranty

The material contained in this docu-ment is provided “as is,” and is sub-ject to being changed, without notice, in future editions. Further, to the max-imum extent permitted by applicable law, Agilent disclaims all warranties, either express or implied, with regard to this manual and any information contained herein, including but not limited to the implied warranties of merchantability and fitness for a par-ticular purpose. Agilent shall not be liable for errors or for incidental or consequential damages in connection with the furnishing, use, or perfor-mance of this document or of any information contained herein. Should Agilent and the user have a separate written agreement with warranty terms covering the material in this document that conflict with these terms, the warranty terms in the sep-arate agreement shall control.

Technology Licenses

The hardware and/or software described in this document are furnished under a license and may be used or copied only in accordance with the terms of such license.

Restricted Rights Legend

If software is for use in the performance of a U.S. Government prime contract or sub-contract, Software is delivered and licensed as “Commercial computer soft-ware” as defined in DFAR 252.227-7014 (June 1995), or as a “commercial item” as defined in FAR 2.101(a) or as “Restricted computer software” as defined in FAR 52.227-19 (June 1987) or any equivalent agency regulation or contract clause. Use, duplication or disclosure of Software is subject to Agilent Technologies’ standard commercial license terms, and non-DOD Departments and Agencies of the U.S. Gov-ernment will receive no greater than Restricted Rights as defined in FAR 52.227-19(c)(1-2) (June 1987). U.S. Govern-ment users will receive no greater than Limited Rights as defined in FAR 52.227-14 (June 1987) or DFAR 252.227-7015 (b)(2) (November 1995), as applicable in any technical data.

Safety Notices

CAUTION

A CAUTION notice denotes a haz-ard. It calls attention to an operat-ing procedure, practice, or the like that, if not correctly performed or adhered to, could result in damage to the product or loss of important data. Do not proceed beyond a CAUTION notice until the indicated conditions are fully understood and met.

WARNING

A WARNING notice denotes a hazard. It calls attention to an operating procedure, practice, or the like that, if not correctly per-formed or adhered to, could result in personal injury or death. Do not proceed beyond a WARNING notice until the indicated condi-tions are fully understood and met.

Revision Log

Revision B, October 2012

Removed Default Settings section

Contents

1 Introduction

750/89 Premium Shielded High Resol

Safety Warnings 6

Compliance Notice 8

Contact Information 9

Europe 9USA 9Agilent website (all countries) 9

Important Notice 10

Disclaimer 10

2 Installation and Operation Safety

Introduction 12

Nature of the Magnetic Field 13

Hazards Presented by the Magnetic Field 14

Magnetic Field Safety Requirements 15

Exclusion Zone (5-gauss line) 15Magnetic Attraction Zone 16Occupational exposure to magnetic fields 16

Nature of Liquid Cryogens 17

Hazards Presented by Cryogens 18

Siting Requirements 20

Vents or quench ducts 20Adequate ventilation during magnet installation 21Oxygen monitor 21Routine maintenance involving transfer of cryogens 22Advice 22

Electrical Safety 23

Safe Access When Working at Height 24

Considerations for the Outbreak of Fire 25

General Safety — Potential Hazards 27

Handling cryogens (liquid helium and liquid nitrogen) 27Vacuum hazards 27Magnetic field 28Air quality 28System mechanical stability 29

ution NMR Magnet System Overview 1

3 Maintenance

2

Commissioning and Decommissioning of the Magnet 32

General safety note 32

Cryostat Maintenance 35

General maintenance 35

Cryogenic Fills 38

Safety during cryogen fills 38How to perform a routine LN2 fill 38How to perform a standard helium fill (top-up) 40

Parts List and Order Form 49

Parts Quotation Request 50Information Sheet 52

4 Reference

Nitrogen Probe Calibration Chart — 750/89 Premium Shielded 54

Helium Probe Calibration Chart — 750/89 Premium Shielded 55

Temperature Sensors — 750/89/ASP 57

Platinum resistor thermometers (PT100) 57Allen-Bradley temperature sensors 57Location of temperature sensors 57

Wiring Diagrams 58

10-Pin seal pin designations – 750/89/ASP 5819-Way shim socket pin designations — 750/89/ASP 61

5 Agilent E5035 Nitrogen Monitor

Safety 66

Compliance Notice 67

Description and Operating Principle 68

Display 68Calibration 69Technical specification 70

6 Agilent E5080 Cryogen Monitor

Safety 72


Description and Specifications 74

E5084 - pressure regulation for twin cryogen magnets 74E5083 - pressure regulation for refrigerated magnets 75Technical specification 77

750/89 Premium Shielded High Resolution NMR Magnet System Overview

750/89 Premium Shielded High Resol

Operation 78

Overview 78Connecting the E5080 to a magnet system 79Using the Menu System 80

Troubleshooting 82

Problems that occur on E5084 and E5083 units 82Problems that occur on E5084 unit only 83Problems that occur on E5083 unit only 84Helium probe hardware errors 86Thermal sensor hardware errors 86Gas Heater hardware error 86

Settings for Hyperterminal 87

To make advanced settings 88To make serial cable pin connections 89Using Hyperterminal to upload logged data 90

Command Instruction Set 91

General commands 91Helium commands 92Thermal channel commands 93Pressure commands 94Gas flow (E5084 only) 94Gas heater (E5083 only) 94Request command 95

Connector Pin Assignments 96

7 Technical Specifications

System Description 100

The Superconducting Magnet 101

General description 101Magnet specifications 101Superconducting shim coils 102

The Cryostat 103

General description 103Cryostat specifications 103

Customer Interface Drawings 106

System Components 111

Superconducting magnet system components 111Standard ancillary parts provided with the system 111Required (not included in standard scope of supply) 111

ution NMR Magnet System Overview 3

4

Agilent 750/89 Premium Shielded High Resolution NMR Magnet SystemSystem Overview

1Introduction

Safety Warnings 6

Compliance Notice 8

Contact Information 9

Important Notice 10

5Agilent Technologies

1 Introduction

Safety Warnings

6

WARNING This device produces a high magnetic field. The stray field surrounding the magnet extends far beyond the confines of the vessel. The existence of this field produces several hazards. In particular, make sure people with cardiac pacemakers avoid the region of field. The FDA guideline for cardiac pacemakers is currently 5 gauss. Fields higher than this can cause malfunction of the pacemaker. The field will interfere with sensitive electronic devices and will erase magnetic storage devices such as tapes and credit cards.

WARNING Ferromagnetic objects in the vicinity of the magnet will become magnetized and will be attracted toward the magnet. The force on such objects is proportional to their mass so that even large objects will move toward the magnet with considerable velocity.

WARNING Under fault conditions, it is possible for large amounts of helium and/or nitrogen to be released from the system (for example, during a magnet quench). Under these conditions, the gas is very cold and can cause “cold burns”. If the gas is not vented properly, asphyxiation is possible due to the displacement of oxygen within the room. It is the responsibility of the user to ensure adequate venting of the gas is provided and adequate ventilation within the final installation site.

NOTE It is the responsibility of the user to take all necessary precautions to prevent accident or loss from use of the magnet. Agilent Technologies accepts no responsibility for any loss or damage caused either directly or indirectly from use of the magnet. Every effort is made that the information contained in this manual is correct. However, Agilent Technologies accepts no responsibility for any inaccurate statements or omissions.


Introduction 1

750/89 Premium Shielded High Resolut

WARNING Limit the magnet power supply to the operating current of the magnet plus 10%. Energize the magnet only after completion of cooling.

NOTE Agilent Technologies makes available technical information and parts for repair or maintenance where appropriate.

ion NMR Magnet System Overview 7

1 Introduction

Compliance Notice

8

Marking by the symbol indicates compliance of this device to the PED (Pressure Equipment Directive) directive of the European Community. This unit is to be installed and operated as detailed. Any modification or maintenance procedure undertaken which is not approved by Agilent

Technologies UK Ltd could nullify the marking of this product and lead to prosecution. A 'Declaration Of Conformity' in accordance with the above directive has been made and is located at Agilent Technologies, Yarnton, Oxfordshire, UK.


Introduction 1

Contact Information

Europe


Address:

Agilent Technologies UK Ltd.

6 Mead Road

Oxford Industrial Estate

Yarnton, Oxfordshire OX5 1QU

Telephone Numbers:

To find contact information for your country, click the following link, select your country, and then click Go.

http://www.chem.agilent.com/en- us/ContactUS/Pages/ContactUs.aspx

USA

Address:

Agilent Technologies, Inc.

5301 Stevens Creek Blvd.

Santa Clara, CA 95051

Telephone Numbers:

Toll Free: +1 (800) 227 9770

Agilent website (all countries)

To find contact information for your country, click the following link, select your country, and then click Go.

http://www.chem.agilent.com/en- us/ContactUS/Pages/ContactUs.aspx


http://www.chem.agilent.com/en-us/ContactUS/Pages/ContactUs.aspx

http://www.chem.agilent.com/en-us/ContactUS/Pages/ContactUs.aspx

1 Introduction

Important Notice

10

Inspect goods immediately on arrival for possible transit damage, and notify Agilent Technologies within three days of receipt of goods. Failure to do this invalidates any possible claim.

Disclaimer

Every precaution has been taken in the preparation of this publication. Agilent Technologies assumes no responsibility for errors or omissions. Neither is any liability assumed for damages resulting from the use of the information contained herein.



2Installation and Operation Safety

Introduction 12

Nature of the Magnetic Field 13

Hazards Presented by the Magnetic Field 14

Magnetic Field Safety Requirements 15

Nature of Liquid Cryogens 17

Hazards Presented by Cryogens 18

Siting Requirements 20

Electrical Safety 23

Safe Access When Working at Height 24

Considerations for the Outbreak of Fire 25

General Safety — Potential Hazards 27



Introduction

12

The site for a superconducting magnet system must meet national, state, and local safety regulations. For magnet systems, site safety issues primarily relate to magnetic fringe fields and handling liquid cryogens. This section summarizes these potential dangers and makes recommendations for the facility.


Installation and Operation Safety 2

Nature of the Magnetic Field


The greatest hazard presented by a superconducting magnet is the fringe magnetic field. Once the magnet is energized, the magnetic field is always present, even when all power to the system is turned off. This magnetic field extends above, below and to the sides of the magnet. It extends through doors, walls ceilings, and floors.

The strength of the magnetic field increases as the magnet is approached. Objects and people at risk from the magnetic field are considered safe outside the 5 gauss line.

NOTE A magnet that has been de-energized but remains at liquid helium temperatures still exhibits a small residual magnetic field. Make measurements of this field, and restrict public access as per national and state requirements. (See “Magnetic Field Safety Requirements” on page 15.)

Occasionally, fault conditions cause magnets to lose their superconducting properties, which in turn causes their magnetic fields to collapse. For a magnet that is actively shielded, before the magnetic field collapses it can momentarily “bloom” slightly beyond its normal dimensions. For further details on this subject for any specific magnet, consult Agilent Technologies.



Hazards Presented by the Magnetic Field

14

The strong magnetic field creates hazards because it strongly attracts ferromagnetic metal alloys. Ferromagnetic metal alloys contain iron, nickel, or cobalt. They are used in most types of tools and equipment and in some surgical implants.

The strong magnetic field can cause the following hazards:

• Projectiles

• Displacement of surgical implants

• Stoppage of electrical and mechanical implants and devices

WARNING If a loose metal object (such as a wrench or pen) gets too close to the magnet, it can become a projectile as the force of the magnetic field pulls the object towards the magnetic center. This metal projectile can seriously injure anyone standing between it and the magnet.

WARNING Ferromagnetic metals are sometimes used in surgical implants and prosthetic devices. The magnetic field can twist metallic implants out of place, causing tissue damage and pain to the person in whom they are implanted, creating a life-threatening situation. Some cardiac pacemakers, biostimulators, and neurostimulators are mechanically activated and can stop in the presence of the magnetic field. This situation can also create a life-threatening situation.



Magnetic Field Safety Requirements


NOTE National and state legislation & requirements differ around the world. In the USA, follow the requirements and guidance issued by the Food & Drug Administration (FDA). In Europe, European Commission (EC) Directive 2004/40/EC applies; follow the guidance issued by the International Commission on Non Ionizing Radiation Protection (ICNIRP).

NOTE Before 1st April 2005, the advisory body for the United Kingdom was the National Radiological Protection Board (NRPB) - a member of ICNIRP. From 1st April 2005 the NRPB merged with the United Kingdom Health Protection Agency (HPA), and became its Radiation Protection Division.

Control the hazards described in the previous sections of this document by establishing two secure and clearly marked zones:

• The Exclusion Zone

• The Magnetic Attraction Zone

Exclusion Zone (5-gauss line)

The exclusion zone comprises the area (rooms and hallways for example) inside the 5- gauss line of the magnet. Prevent individuals with cardiac or other mechanically active implants from entering this area.

The magnetic field surrounds the magnet in a three- dimensional fashion. Limit access and warn individuals who are potentially at risk, not only at the same floor as the magnet, but also at the levels above and below the magnet.

Enforce the exclusion zone with a combination of warning signs and physical barriers. The following figure shows the warning sign recommended by Agilent Technologies.


16


Figure 1 Warning sign

Magnetic Attraction Zone

NOTE At magnetic field strengths of approximately ten gauss or more, magnetic media can become wiped or damaged.

The “magnetic attraction zone” is established to prevent ferromagnetic objects from becoming projectiles; it is usually confined to the room that houses the magnet. The magnetic attraction zone threshold is usually at a magnetic field strength of 30 gauss.

Occupational exposure to magnetic fields

WARNING Do not allow ferromagnetic objects inside the Magnetic Attraction Zone.

Consult national and state enforcement and advisory bodies to ensure that any exposure limits are not infringed for (nonpatient) occupational workers.



Nature of Liquid Cryogens


A superconducting magnet uses two types of cryogens: liquid helium and liquid nitrogen. Helium is a naturally occurring, inert gas that becomes a liquid at approximately 4K. It is colorless, odorless, nonflammable, and nontoxic. In order to remain in a superconducting state, the magnet is immersed in liquid helium.

Nitrogen is a naturally occurring gas that becomes liquid at approximately 77K. It is also colorless, odorless, nonflammable, and nontoxic. It is used to cool the shield that surrounds the liquid helium reservoir.

During normal operation, liquid cryogens evaporate and require replenishment on a regular basis.

CAUTIONIt

Cryogens are delivered to the site in Dewars; these Dewars, including any carriers, must be nonmagnetic.



Hazards Presented by Cryogens

18

Helium and nitrogen in both their liquid and gaseous forms, present the following hazards:

• A large quantity of gas released in an area that is not well ventilated can cause asphyxiation.

• Liquids or cold gases can cause cryogenic burns.

• The filling procedure produces an oxygen- rich liquid, which is a fire hazard when it drops on a combustible material.

The extremely low temperature of the liquids and their cold vapors can cause severe frostbite, or a cryogenic burn. These low temperatures are mainly a danger during the filling process, when the fill line and other equipment freezes.

WARNING Touching the fill line or any other piece of equipment during a transfer can freeze the skin or cause it to stick to the surface of the equipment.

To prevent cryogenic burns, wear safety footwear, protective gloves, and a face shield. Long- sleeved clothing and long trousers or pants are also recommended.

During the filling process, atmospheric air condenses on the fill line or pipes, leaving an oxygen- rich liquid, or even liquid oxygen. If this drips onto a combustible material, like oil or grease, it can cause a fire.

WARNING Liquid oxygen can spontaneously ignite upon contact with oils or greases.

For these reasons, note the following recommendations:

• Exclude all sources of ignition from magnet rooms.

• Keep all tools and equipment used for transferring cryogenic liquids clean and free from oils and grease.

• Exclude all sources of ignition from the magnet room, which is also designated as a No Smoking zone.




WARNING Helium or nitrogen gas released in an area that is not well ventilated can displace air and reduce the oxygen content to an unsafe level, leading to asphyxiation.

Also note that, when cold, gaseous helium remains lighter than air, but gaseous nitrogen is heavier than air. The greatest risk of asphyxiation is during commissioning of the magnet. However, after the magnet is in service, a risk of asphyxiation can still occur during a “quench”.

A “quench” occurs when the magnet loses its superconductivity, and warms the liquid helium, causing it to turn to gas. This large amount of gas escapes through the magnet venting. The following section describes the safety recommendations that prevent the possibility of asphyxiation after a magnet quench.



Siting Requirements

Vents or quench ducts

20

In order to reduce the risk of asphyxiation in the event of a quench, vent the helium exhaust from the magnet to the outside of the building. Make sure the ducting to the outside of the building is of large enough diameter to avoid excessive pressure build- up due to the flow impedance of the duct. (This exhaust ducting is often referred to as a “quench duct”.) Only allow service personnel to have access to the exit end of the quench duct. In addition, protect the exit opening from the ingress of rain, snow, or any debris which can block the system. Inspect the quench duct exit periodically to ensure that the presence of debris does not restrict the gas flow.

It is also essential to ensure that any gas which vents from the quench duct cannot be drawn into any air conditioning or ventilation system intakes. Carefully locate the exit of the duct to prevent this situation from happening in all atmospheric conditions and winds.

Although “quenches” are short- lived and infrequent phenomena. However, as quench gases are liberated, the temperature of the quench duct can become low enough to cause cold burns on unprotected skin. This cold can also damage electrical wiring or other services routed close enough to touch the quench duct. (Do not route water pipes near quench ducts.) Make sure that quench ducts are protected with suitable proprietary thermal insulation, such as fiberglass cladding or the equivalent. Make sure that the thermal insulation is:

• Fire resistant (due to the possibility of condensation of liquid oxygen)

• At least 50 mm thick

• Resistant to deterioration upon contact with water (Frost formed on the pipe within the thermal insulation eventually thaws.)

If a quench duct fails during a quench, gas can release rapidly into the magnet room, causing the pressure to rise (and create an asphyxiation hazard there). This pressure rise can prevent an exit through inward- opening doors along escape routes. For safety, make sure that exit doors always open outwards, away from the magnet.

Provide a secondary escape route for large volumes of




quench gases by installing a passive vent opening directly from the magnet room to the outside. Make sure that this opening has, as a minimum, the same cross- sectional area as a quench duct. An opening measuring 400mm x 400mm is normally sufficient. To ensure that this passive vent is fail- safe, do not include active control for the vent opening; do not use fans or mechanical shutters.

Adequate ventilation during magnet installation

During the installation and cooling of superconducting magnets, large volumes of nitrogen or helium gases are sometimes generated. Although these gases are inert, if generated in large enough quantities, they can create dangerous circumstances if they displace the oxygen in the room. The following table provides examples:

Table 1 Examples of gas generation

Magnet Type

Quantity of liberated N2

gas during precool

Time taken to liberate N2 gas during precool

Quantity of liberated He gas during filling

Time taken to evolve He gas during filling

Quantity of He gas liberated during a “quench”

Time to liberate He gas during a “quench”

800/89 3400 m3 40 hours 1750 m3 14 hours 800 m3 1 min

900/52 13600 m3 160 hours 7000 m3 56 hours 315 m3 1.5 min

4T940 5400 m3 48 hours 5400 m3 72 hours 900 m3 10 min

Oxygen monitor

WARNING Adequate means of transporting evolved gases from the magnet out of the magnet room and also good ventilation of the magnet room is essential.

NOTE An oxygen monitor is recommended for the magnet room. See the Site Planning Guide for recommendations. Make sure the audio/visual alarm connected to an oxygen monitor is visible/audible outside the magnet room as well as inside it.

The oxygen monitor sounds an alarm when the oxygen level in the room rises above or falls below a safe level. This alarm happens if the ventilation system malfunctions, either during a quench or during a normal boiloff, and a large


22


amount of helium gas is released into the room.

Routine maintenance involving transfer of cryogens

Advice

WARNING For safety reasons, allow only personnel with formal maintenance training to perform routine maintenance tasks involving transfer of cryogenic liquids.

If you have any queries concerning your siting requirement, advice can be obtained from the Installation Manager at Agilent Technologies.



Electrical Safety


Always observe the following precautions and safe practices:

WARNING Electric shock hazard. Isolate or disconnect equipment from mains supply before opening this unit for any reason.

WARNING For continued protection against risk of fire or electric shock, always replace fuses with the same type, rating, and UL listing.

CAUTION Magnets power supplies contain internal protection fuses, follow the guidelines in the trouble-shooting section of the magnet manual before replacement of these devices.

CAUTION Your magnet power supply has been preset to a voltage range suitable for the national supply of your country. If any fuses require replacement, always use the correct type and rating.



Safe Access When Working at Height

24

Safe access to the top of magnets is important for routine topping up of cryogens; the frequency of doing so varies from magnet to magnet, but can be needed as often as weekly. Safe access to the top of magnets is also essential for installation work. Normal ladders and stepladders are not best suited to this task: They often fail to offer a secure platform when working on top of magnets and performing tasks that require the use of both hands.

Select and purchase suitable access equipment before the arrival of the magnet. Make sure that all equipment is nonferrous and immune to magnetic attraction. To aid in choosing the height and size of access equipment in advance of the magnet arrival, refer to the magnet System Interface Drawing that is sent in advance to all customers.



Considerations for the Outbreak of Fire


Specific precautions regarding fire safety vary depending on legislation and regulations in the country where the magnet is installed. The considerations discussed in the following sections are intended to help customers review their site fire precautions following the installation of a superconducting magnet. These considerations are advisory in nature.

There are two types of fire that can affect a magnet room – small fires and large fires. In this document “small fires” are defined as fires of a size that personnel can choose to fight with a first aid fire extinguisher. “Large fires” are defined here as major fires that only professional fire fighters are qualified to extinguish.

Small fires. Most premises already have fire and emergency procedures in place, in accordance with current safety legislation. Make sure any fire extinguisher provided in a magnet room, or taken into a magnet room in response to a fire, is of nonferromagnetic construction. Otherwise, it can become attracted to the magnet, causing personal injury, and becoming useless for fire fighting purposes.

Large fires. Most premises already have fire and emergency procedures in place, in accordance with current safety legislation. For maximum safety, invite the Fire Department (or Fire Brigade) for a liaison visit to inspect the building layout and the hazards associated with superconducting magnets. It is important for the Fire Department (or Brigade) to understand – before attending a major fire at a magnet lab – the hazards in addition to flames and smoke that these installations represent. The hazards to discuss with professional fire fighters include the following:

Magnetic attraction of ferrous equipment. Assuming the magnetic field warning signs are still intact when fire fighters, most firemen do not understand the strength of magnetic attraction that superconducting magnets generate. These magnetic fields can attract firefighting equipment and endanger the firefighters themselves.

Quenches. Quench ducts can fail in a large fire or be broken by falling debris, liberating quench gases into the magnet room, creating a risk of asphyxiation for any fire fighters present. Magnet rooms with several vertical magnets,


26


which do not possess dedicated quench ducts, can be faced with more than one magnet quenching simultaneously, venting large quantities of nitrogen or helium gas into the magnet room. Because these gases are inert, with nitrogen comprising 80% of the air we breathe, as few as three breaths of 100% inert gas can cause asphyxiation. Magnet rooms of very large volumes can represent a lower risk than magnet rooms of small volumes. However, always advise fire fighters of the asphyxiation hazard, and suggest they wear breathing apparatus when fighting a fire in a magnet room.

Explosions. In a disaster scenario, magnets very close to or enveloped in flames get very hot, causing them to quench and rapidly release inert gases, possibly faster than their pipes and fittings normally permit. In the worse case, a magnet can become over pressurized and explode. If magnets become physically hot in a fire, Treat them in a similar way to hot compressed gas cylinders: hosed down and kept cool.

Fire Doors and Exits. Make sure fire doors and exits from magnet rooms open outwards. In a disaster scenario, if large quantities of gas are vented into the magnet room, the pressure in the room can rise, making inward- opening doors difficult to open. This situation can make access difficult for fire fighters, or potentially fatal for anyone still inside the magnet room.

WARNING Although large fires are unlikely, always evacuate all staff before a fire becomes fully established, following standard fire procedures or evacuation plans.



General Safety — Potential Hazards

Handling cryogens (liquid helium and liquid nitrogen)


Vacuum hazards

WARNING For safety reasons, allow only personnel with formal training to perform routine maintenance tasks involving the transfer of cryogenic liquids.

Wear safety goggles, loose fitting nonabsorbent gloves, long trousers, a long-sleeved shirt, and nonferrous safety footwear.

Ensure adequate ventilation and oxygen monitoring of the area consistent with the volume of cryogens being used. If the oxygen level in the room falls below 19.5%, do not allow personnel to enter the area without self-contained breathing apparatus or airline respirators.

Do not smoke. Ensure that other sources of ignition are not present. Liquid oxygen can condense on cold surfaces and cause a fire hazard.

Never measure the helium level by “dipping” or “thumping” the helium can; always use the integral level probes in order to gauge the volume of liquid remaining.

WARNING Keep cryostat exhaust ports free from blockages such as ice.

Ensure all safety devices (relief valves and drop-off plate) are maintained in working order.

Do NOT tamper with any vacuum seals or attempt to unscrew vacuum feed-through connections.



Magnetic field

28

WARNING Siting of the magnet must be consistent with local legislation on allowable levels of stray magnetic field.

Do not allow people with heart pacemakers or metallic body implants within the vicinity of the magnet (within the 5G (0.5 mT) line).

Keep gas cylinders away from the magnet (outside the 5G (0.5 mT) line).

Keep all other large ferromagnetic objects away from the magnet. Use steel tools near the magnet only with great care and when nonmagnetic alternatives are not available.

Due to the nature of shielded magnets, there are very high field gradients close to the magnet. These fields are particularly high at the ends of the bore tube (for example, directly underneath and on top of vertical magnets, and at each end of horizontal magnets).

In the rare event of a magnet quench, it is possible for the magnetic field to bloom momentarily beyond its normal limit, attracting ferromagnetic objects towards the magnet. For this reason, do not place or store ferromagnetic objects within 1 meter of the cryostat.

Air quality

CAUTION Keep all forms of magnetic storage media outside the 10G (1 mT) line, including credit cards, computer hard disks, and floppy disks. Mechanical watches are also at risk.

WARNING Maintain adequate ventilation of the room in which the system is located.

See “Handling cryogens (liquid helium and liquid nitrogen) ” on page 27.

Oil mist from rotary vane vacuum pumps is a potential health hazard: vent the exhaust from pumps to the outdoors. Make sure any flexible hoses used for this purpose are kink-resistant and have a push-on engagement with the exhaust port of the vacuum pump. (Do not clamp hoses onto pumps.)



System mechanical stability


WARNING The antivibration legs supplied with the system MUST be leveled and bolted to the floor using the relevant holes in the base fixing plate. Perform this operation at the beginning of the magnet installation, before the magnet is energized.

Do not stand on the legs hoods at any time, to avoid affecting the stability of the system. Protective leg hood covers are fitted to prevent this situation from happening.


30




3Maintenance

Commissioning and Decommissioning of the Magnet 32

Cryostat Maintenance 35

Cryogenic Fills 38

Parts List and Order Form 49


3 Maintenance

Commissioning and Decommissioning of the Magnet

General safety note

32

For reasons of safety and to avoid damage to the internal fixtures in the cryostat, allow only skilled and suitably trained personnel to remove the system from the crate or detransit the magnet. Do not allow untrained personnel to attempt these tasks.

Storing transit fixtures

Once the system has been detransited, safely store the transit fixtures for future usage. If the magnet is moved, these fixtures are required to prevent damage during transportation. Transit bungs are individually machined to fit each system and are not easily replaced if lost. See the following table for a list of all of these transit features. Space is provided in this table to record the storage location of each item for future reference.

Table 2 Transit features

Transit feature Part number Quantity Storage location

Transit bung (bottom) DNC137367 3

Top shipping bung cover plate DNC338124 1

Top shipping bung body DNC337715 1

Top shipping bung top plate DNC338123 1

O-rings 126 ID x 3 sec P171126030 3

Screws and washers — —

Decommissioning of the magnet

Only allow suitably trained personnel to move or ship the magnet. If all the transits are not correctly fitted on the system, or if it is packed or shipped incorrectly, the system can be damaged. Contact Agilent Technologies for information about services for decommissioning and recommissioning magnets.


Maintenance 3


Energizing direction

All Agilent Technologies magnets are energized in a standard direction as defined in this section, unless otherwise requested by the customer at the time of ordering.

The magnet is energized such that the North is at the top of the magnet, and the South is at the bottom. The following procedure describes how to check the polarity.

1 Align the compass to geographic north outside of the building, away from all magnetizable structures. Note which end of the needle points to geographic north. (Geographic north pole coincides with magnetic south pole.) In the following steps, this end of the needle is referred to as the “N end of the needle”.

2 Approach the ends of the magnet with the compass, continuously observing the needle. Keep the compass away from the magnetized elements, because they can demagnetize the compass needle.

3 Proceed as described above. The “N end of the needle” must point to the bottom of the magnet (pointing up the bore tube from the floor). This is the S end of the magnet. The reverse is checked at the top of the magnet (the “S end of the needle” must point down towards the bore tube from the top of the magnet, indicating that this is the N end of the magnet).

4 Repeat by aligning the compass to geographic north outside the building, away from all magnetizable structures. Ensure that the same end, the “N end of the needle”, points to the geographic north as before. This confirms that the compass was not demagnetized, and the measurement was successful.


34

3 Maintenance

Figure 2 Magnet orientation


Maintenance 3

Cryostat Maintenance

General maintenance


Regular maintenance tasks are essential for the efficient and reliable operation of this system. These tasks generally include checking cryogens, making sure that the system is leak- tight, and checking that none of the parts are worn or damaged. A routine maintenance schedule is recommended.

Daily

• Check flow- rates and note cryogen levels to see whether refills are required.

• The cryogen monitor acts as a manostat, keeping the pressure within the helium can constant. Check the reading on the cryogen monitor display daily to confirm that the system is maintaining the set pressure. If the cryogen monitor cannot maintain the pressure, then this can indicate a helium leak. If the pressure is higher than the set pressure, then a blockage is indicated. In both of these cases, quickly identify the source of the problem and resolve it.

Weekly

• Check that all safety valves are free and are not iced- up.

• Check that all seals are air- tight, especially after a helium top- up.

• Check that the cryogen levels in the log are consistent, (dropping regularly). A false reading can result if ice develops on the helium probe, and the level ceases to drop. If this condition is suspected, contact Agilent Technologies for advice.

Monthly and annually

• Check monthly that quench ducting (where fitted) remains unobstructed.

• Check at least annually that the burst disk is intact and replace as necessary.

During/after every nitrogen fill

• Check the o- rings on the heat sink assembly and the nitrogen safety valve (small silver valve) for wear and tear. If they are excessively worn or broken, replace them.


36

3 Maintenance

During/after every helium fill

• Ensure that the check valve on the helium exhaust manifold is refitted and that the ball valve is left in the open position.

• Check the o- rings on the bung and baffle assembly for wear and tear. If there is any sign of wear, replace the o- ring.

• Check the condition of the baffles. If they become torn or cannot be straightened, then consider a replacement set.

• Check that the nitrogen vent is clear and is not iced- up.

• Check that the helium monitor is reset to the minimum sample rate (“normal”).

• Check that the shim lead fitting (bung and nut) is tight. (Wait for the ice to melt to do this.)

• Check that all seals are correctly made and are leak- tight. For example, check that the o- ring and carrier between the manifold and non- return valve are correctly tightened with the clamp, and that the bung and baffles are correctly fitted with compression seals. The correct compression seal arrangement is shown in the following figure.

Figure 3 Compression seal arrangement


Maintenance 3


Cryogen and service log

It is good practice to keep a log of cryogen usage and maintenance. An increase in cryogen consumption over time can indicate that the vacuum space needs to be repumped. A reduction in boiloff can indicate a leak or blockage. In addition, it is useful to calculate the helium transfer efficiency during a helium fill. Calculate the efficiency by comparing the volume of helium used from the Dewar, to the volume increase in the magnet helium can (75% to 85% is usual for a 2m span siphon). A degradation in helium transfer efficiency can indicate poor vacuum in the transfer siphon, or a damaged siphon.

A suggested layout for a cryogen and service log is shown in Table 3.

Table 3 Example cryogen and service log

Date Helium Nitrogen Notes/Service details

Level probe (%)

Quantity used for refill

Level probe Quantity used for refill

1 Dec YY 28 - 2 -

2 Feb YY 27 - 2 -

2 Mar YY 26 - 1 -

4 Apr YY 26 - 1 -

3 May YY 25 - 1 -

4 Jun YY 100 ~90 liters F ~90 liters Helium and Nitrogen filled

Servicing

If you have any concerns about your system, contact Agilent Technologies for technical advice or to arrange a service visit. A list of contacts is provided at the beginning of this manual.

In order to avoid any difficulties and potential safety issues, use only Agilent Technologies approved parts on the system.


3 Maintenance

Cryogenic Fills

Safety during cryogen fills

38

WARNING For safety reasons, allow only formally trained personnel to perform cryogenic top-ups.

How to perform a routine LN2 fill

WARNING Wear safety goggles and loose fitting nonabsorbent gloves.

Ensure adequate ventilation and oxygen monitoring of the area consistent with the volume of cryogens being used. If the oxygen level in the room falls below 19.5%, do not let personnel enter the area without self contained breathing apparatus or air line respirators.

Do not smoke. Liquid oxygen can condense on cold surfaces and cause a fire hazard.

Never measure the helium level in the magnet cryostat by “dipping” or “thumping” the helium can.

WARNING Do not let the pressure in the nitrogen can exceed 5 psi. Ensure that the transport vessel has suitable pressure control.

The procedure given in this section assumes that there is some liquid nitrogen left in the nitrogen can. Cooling and filling an empty nitrogen can requires additional precautions. Contact Agilent Technologies if you suspect that the liquid nitrogen has run out.

The initial precool of the magnet helium can and nitrogen can is a skilled task. Allow only suitably qualified personnel to perform this task.

CAUTION It is important to stop the transfer once LN2 is seen to issue from the nitrogen can. If the system is left unattended, it is possible to freeze the OVC o-rings and cause a catastrophic loss of vacuum.


Maintenance 3


Make sure that the liquid nitrogen reservoir is refilled regularly and liquid nitrogen remains in the reservoir at all times. Refer to the Nitrogen Probe Calibration Chart for information on when to refill the nitrogen can, typical refill volumes, and minimum nitrogen hold times. The Nitrogen Probe Calibration Chart is also provided as a separate, laminated sheet.

To refill the reservoir, the nitrogen fill adaptor and the nitrogen transfer line (5m provided) are required, as well as a nonmagnetic nitrogen storage Dewar of suitable capacity. If the nitrogen Dewar is not of the self- pressurizing type, then a regulated nonmagnetic cylinder of helium or nitrogen gas is also needed.

To improve transfer efficiency, fit insulation to the transfer line. Simple, cheap, easily available, and replaceable expanded foam pipe lagging works well. Trials showed that Armaflex Tuffcoat insulation (20mm internal diameter, and 13mm insulation thickness), although slightly more expensive, was more robust and was the most effective insulation trialled to improve nitrogen transfer efficiency. Use a suitable waterproof tape to preserve the integrity of the insulation, and to prevent air/water ingress into the lagging at the joints and the ends. All insulation freezes during the nitrogen transfer, and if moved when cold, it cracks. Repeated freeze/thawing also degrades the insulation. Allow the insulation to thaw before removing, and replace as necessary.

The top- up procedure is simple.

1 Remove the safety valve (small silver- colored valve) by loosening the grub screw, and the heat sink assembly from the nitrogen turrets. This provides two free turrets for the fill.

2 Connect the liquid outlet of the storage Dewar to one of the ports via the transfer line.

3 Transfer the liquid nitrogen using a back- pressure in the storage Dewar of about 6 psig.

4 Continue the transfer until liquid starts to overflow from the free port of the system nitrogen reservoir; this takes about 30 minutes on most systems.

5 After the fill, check that the o- rings are in good condition and then return the heat sink assembly and the safety valve to the turrets.

6 Tighten the grub screw on the safety valve.


40

3 Maintenance

7 Check that the digital nitrogen monitor is reading full. If not, follow the simple instructions for recalibrating the nitrogen probe outlined in the cryogen monitor manual provided.

How to perform a standard helium fill (top-up)

The calibration charts and minimum levels for the helium probes are given in Chapter 4, “Reference”. A separate Helium Level Chart was also provided for your reference to locate near the magnet.

This system has one main service turret, with 4 entry ports and a series of 10- pin seals. Perform a helium top- up through the shim entry port (the tallest port), using adapter AUC330649, provided.

Figure 4 Magnet service turret showing the recommended helium fill entry port

For the helium top- up, the helium siphon, phase separator, and the helium fill adapter (all provided) are required. In addition, a nonmagnetic helium storage Dewar of appropriate capacity is required.

Follow these instructions carefully to ensure that the magnet is topped up quickly, cleanly and efficiently. This minimizes any exposure of the helium can to air, avoids damage to connectors and baffles, and helps maintain the original helium hold- time. It also keeps the helium can clean and


Maintenance 3


free of ice. It is important that the helium can remains leak tight at all times, and therefore the compression seals must be fitted correctly as shown.

Figure 5 Compression seal arrangement

1 Determine the amount of liquid helium required to top- up the helium can.

The volume is determined from the helium level chart provided. Make sure you have enough liquid helium in a nonmagnetic storage Dewar available to fill the helium can entirely plus transfer losses (normally transfers are 80% efficient). The liquid level in the helium transfer Dewar (not the magnet) is determined with the “dipstick” or “thumper- tube”. This part is only included with selected products, however it is available for purchase from Agilent Technologies.

2 Make sure all the nitrogen ports are well sealed before starting the helium fill.

WARNING The liquid nitrogen can become supercooled due to the thermal linking within the cryostat. This results in zero boil off, which in turn can allow air to cryopump into the nitrogen can, forming air-ice and blocking the exhaust ports, creating a serious safety hazard.


42

3 Maintenance

Figure 6 Location of nitrogen ports

3 Check all seals on the service turret are correctly fitted and tight before starting. This includes checking all the knurled nuts on the service turret, including the 10- pin seals.

Figure 7 Close up view of service turret

4 On the helium exhaust manifold at the top of the cryostat, close ball valve B.

5 Remove overpressure check valve C.

6 Re- open the ball valve to release the excess pressure, being careful to avoid the outrushing stream of cold helium gas.

7 Keep ball valve B open until after the fill procedure is complete. (If the fill procedure is interrupted for more than a few minutes, replace the overpressure relief valve during the period of interruption to avoid excessive ingress of air. Remember to remove it again when restarting the fill.)


Maintenance 3


Figure 8 Helium exhaust manifold

8 Check that the cryogen monitor is giving a reading of the liquid helium level.

9 Set the cryogen monitor for the helium to read on “Helium Fill” mode (see monitor manual for instructions).

10 The adapter and fittings should be fitted to the siphon in advance. Push the knurled compression nut, the o- ring, and the special fill adapter (part number AUC330649) in this order, onto the leg of the siphon, which will go into the cryostat. Push them all of the way to the top of the siphon leg (the junction with the right- angled bend).


44

3 Maintenance

Figure 9 Fitting of adapter and fittings to the siphon

11 Fit the phase separator or “deflector tip” (part number DTU400032) to the bottom of the siphon leg that goes into the helium can. If required, fit the siphon extension piece to the siphon leg to be inserted into the Dewar.

Figure 10 Phase separator connection and siphon extension fitting

12 Loosen the nut on the shim port of the service turret, but do not remove.

13 Pre- cool the siphon. Insert the transfer line into the transfer Dewar top seal and then open the top valve. Insert the transfer siphon into the liquid in the Dewar, which causes the liquid to boil and the pressure to rise. As the siphon cools, the vapor becomes denser and more opaque, and eventually the transition is made from vapor to liquid. This usually takes a couple of minutes. The liquid vaporizes immediately on contact with air.


Maintenance 3


If during this process, the transfer line develops frost or is cold to touch, then the transfer siphon can have insufficient vacuum or may be damaged. If this situation is suspected, stop the helium fill until the problem with the transfer siphon is resolved. If there is insufficient vacuum in the transfer siphon, then it can be pumped down using a vacuum pump connected to the siphon, using a siphon pump out tool (part number P222000008, available from Agilent Technologies). If the siphon is damaged and has a touch, then a replacement may be required.

Figure 11 Top seal of the Dewar


46

3 Maintenance

Figure 12 Inserting transfer line into the top seal of the Dewar

CAUTION Failure to pre-cool the siphon may quench the magnet as the warm siphon is inserted into the helium can. If the siphon is suspected to be soft or have a touch, do not insert into the helium can, as this may also cause the magnet to quench.

14 After the siphon precool is complete and helium liquid is issuing from the phase separator, remove the helium non- return valve from the service turret, remove the bung and baffle assembly from the shim entry port, and insert the siphon and adapter assembly, screwing down the nut to ensure a good compression seal.

Figure 13 View showing the helium siphon inserted into the service turret


Maintenance 3


15 Gently push the siphon into the helium can until you feel it touch a barrier (connector) and then withdraw it about 50 mm (~2 inches).

16 Continually monitor the helium level to ensure that the fill is progressing well.

Figure 14 Side view of the helium siphon inserted into both magnet and transfer Dewar for a helium transfer

17 When full, take the pressure off the transfer Dewar to stop the transfer.

18 Refit the helium nonreturn valve to the service turret.

Figure 15 Helium siphon in the transfer Dewar showing it lifted from the base of the Dewar


48

3 Maintenance

19 Inspect the bung and baffle assembly for damage and ensure that it is warm and dry (no water droplets) before refitting. Remove the siphon and adapter, and replace the bung and baffle assembly, tightening the nut to form a good compression seal. If the baffles appear to be getting damaged such that they are broken or cannot be restraightened, then consider a replacement set. You can order a replacement set using the parts order form in this chapter. The use of significantly damaged baffles (or omitting the baffles completely) will result in reduced performance of the system.

20 On the helium exhaust manifold at the top of the cryostat, close ball valve B.

21 Refit overpressure check valve C.

22 Re- open ball valve B and leave it in this configuration.

23 Remember to change the helium probe reading back to “normal” again.

24 Once the service turret has warmed up after the fill, recheck the o- ring seal and retighten if necessary.

CAUTION Due to the excellent cryogenic efficiency of the cryostat in normal operation, it is common for the helium and/or nitrogen boil-off to fall to zero immediately after a transfer or after magnet energization. There is then a serious risk of air entering the helium and/or nitrogen reservoir. However, if the procedures detailed above are followed correctly, any associated problems can be avoided.


Maintenance 3

Parts List and Order Form


The following lists give part numbers for replacement parts for use with this magnet. You can photocopy the forms and then fax or send them to the Sales Department at Agilent Technologies for quotation. The parts listed are the general consumables and ancillaries required for normal operation. Contact the service department for any other parts required.

Remember to copy both the order form and the contact details, and send them to the Sales Department.

For addresses, fax numbers, and telephone numbers, see “Contact Information” on page 9.


3 Maintenance

Parts Quotation Request

50

Part Description Quantity required

P200000059 Burst & tell disk

P200000061 Burst disk monitoring indicator

P170OR2056 O-ring for 10-pin seals in top-hat

P170OR3100 O-ring for shim turret bung (with baffles)O-ring for helium fill adapter (seal body assembly)

DUC400007 Seal nut 25.4mm for P170OR3100

KC25AV O-ring/centering ring for KF25 flanges

KQ25AW Aluminium KF25 clamp for KC25AV

P170OR3050 O-ring for siphon entry of helium fill adapter

DUC400015DUC400014

Seal nut and washer for P170OR3050

P171036530 O-ring for heat-sink assembly (nitrogen port ice preventer)O-ring for nitrogen turret filling cap assembly

P170OR2050 O-ring for nitrogen safety valve (silver valve)

ANC338629 Bung and baffle assembly (helium siphon port)

ANC338628 Bung and baffle assembly (shim lead port)

ANC338627 Bung and baffle assembly (energisation lead port)

AUC330649 Helium fill adapter (seal body assembly)

AUC434904 Helium non-return valve (1.5 psi)

P222000072 Helium transfer siphon (and extension tube)

DTU400032 Phase separator

P222000109 Helium siphon pump-out tool

P222000075 2 part thumper tube (dipstick) - for use in fill Dewar only

AHC340869 Nitrogen turret filling cap assembly

ATU327906 5m Nitrogen transfer line – flare fitting

AUC500209 Nitrogen safety valve (small silver valve)

ANC312474 Nitrogen port ice preventor (heatsink) with non-return valve fitted

C0025085 Cable for double helium probe


Maintenance 3

C0443120 Cable for nitrogen monitor data/power

C0444010 Cable, power supply unit nitrogen monitor

P210000041 Fuse, HBC 2A, for helium monitor.

750/89 Premium Shielded High Resolution NMR Magnet System Overview 51

3 Maintenance

Information Sheet

52

Fax this information sheet with your order to the Sales Department at Agilent Technologies at the Fax number or address listed in “Contact Information” on page 9.

Magnet Serial Number(see serial number plate on cryostat, or system manual)

Name:

Site:

Contact Address:

Telephone number:

Fax number:

Email address:


Agilent 750/89 Premium Shielded High-Resolution NMR Magnet SystemSystem Overview

4Reference

Nitrogen Probe Calibration Chart — 750/89 Premium Shielded 54

Helium Probe Calibration Chart — 750/89 Premium Shielded 55

Temperature Sensors — 750/89/ASP 57

Wiring Diagrams 58


4 Reference

Nitrogen Probe Calibration Chart — 750/89 Premium Shielded

54

• System should be refilled when digital reading changes from 1 to 0.

• The nitrogen remaining in the can will last a minimum of 83 hours.

• The refill volume will be in the range 211.8 and 246.5 liters.

• Minimum hold time is 21 days.

Table 4 Nitrogen probe calibration chart — 750/89 Premium Shielded

Nitrogen probe digital readout

Height range on probe for digital reading (mm) Volume range remaining (l)

min max min. max.

0 0 63.3 0.0 34.7

1 63.3 189.9 34.7 57.0

2 189.9 316.5 57.0 79.3

3 316.5 443.1 79.3 101.6

4 443.1 569.7 101.6 123.9

5 569.7 696.3 123.9 146.2

6 696.3 822.9 146.2 168.5

7 822.9 949.5 168.5 190.8

8 949.5 1076.1 190.8 213.1

9 1076.1 1202.7 213.1 235.4

F 1202.7 1266 235.4 246.5

750/89 Premium Shielded High-Resolution NMR Magnet System Overview

Reference 4

Helium Probe Calibration Chart — 750/89 Premium Shielded

750/89 Premium Shielded High-Resolu

Table 5 Helium probe calibration chart — 750/89 Premium Shielded

Probe/Monitor Reading Helium Level in Cryostat

(%) (mm) (mm) (liters remaining)

100 365 1400 940.1

95 352 1387 927.1

90 338 1373 914.1

85 325 1360 901.1

80 311 1346 888.1

75 298 1333 875.2

70 284 1319 862.2

65 271 1306 849.2

60 257 1292 836.2

55 244 1279 823.2

50 230 1265 810.2

45 217 1252 797.2

40 203 1238 784.3

35 190 1225 771.3

30 176 1211 758.3

25 163 1198 745.3

20 149 1184 732.3

15 136 1171 719.3

10 122 1157 706.3

5 109 1144 693.3

0 95 1130 688.5 MIN REFILL LEVEL

-20 76 1111 670.2

-40 57 1092 651.9

-60 38 1073 633.6

-80 19 1054 615.4

-100 0 1035 597.1

tion NMR Magnet System Overview 55

56

4 Reference

Note: There is a ‘dead volume’ between the top of the helium can and the top of the helium level probe that will not be shown by the helium level meter.

Specification minimum hold time is 120 days.


Reference 4

Temperature Sensors — 750/89/ASP


Temperature sensors have been fitted to this system for use on installation and for diagnostic purposes. Two sorts of temperature sensors are fitted, Platinum resistor thermometers and Allen Bradley temperature sensors. Platinum resistor thermometers (PT100) are useful for measuring temperatures between room temperature and 77K. Allen- Bradley temperature sensors are more accurate at lower temperatures (below 77K) to liquid helium temperatures.

Platinum resistor thermometers (PT100)

These sensors have a nominal resistance of 100 Ohms at 0°C (273K) which falls linearly to a typical resistance of 20 Ohms at 77K.

Allen-Bradley temperature sensors

Allen- Bradley temperature sensors are individually calibrated, and are specific to each system. If required, sensor calibrations are available from Agilent Technologies.

Location of temperature sensors

The temperature sensors fitted to this system are outlined below.

Table 6 Temperature sensor locations

Sensor type Location Access

Allen Bradley Gas-cooled shield ABDE 10-pin seal on side of cryostat

PT100 Nitrogen can HJKL 10-pin seal on side of cryostat

Allen Bradley Helium CanBaseplate

KL 10-pin seal with black nut on service turretKL 10 pin seal with blue nut on service turret

PT100 Helium CanBaseplate

EFHJ 10-pin seal with blue nut on service turret.

PT100 Lead Runner ABCD 10-pin seal with blue nut on service turret.


4 Reference

Wiring Diagrams

10-Pin seal pin designations – 750/89/ASP

58

Figure 16 Pin arrangement in the 10-pin connectors on the magnet

Table 7 OVC 10-pin seal

Pin Function

A GCS AB270 I+

B GCS AB270 I-

C

D GCS AB270 V+

E GCS AB270 V-

F

H Nitrogen Can PT100 I+

J Nitrogen Can PT100 I-

K Nitrogen Can PT100 V+

L Nitrogen Can PT100 V-


Reference 4


Table 8 Black 10-pin seal nut on service turret

Pin Function

A Fixed He probe V+

B Fixed He probe I+

C Fixed He probe V-

D Fixed He probe I-

E Spare He probe V+

F Spare He probe I+

H Spare He probe V-

J Spare He probe I-

K Base plate AB270 I+

L Base plate AB270 I-

Table 9 Blue 10-pin seal nut on service turret

Pin Function

A Top PT100 V+

B Top PT100 I+

C Top PT100 V-

D Top PT100 I-

E Base plate PT100 V+

F Base plate PT100 I+

H Base plate PT100 V-

J Base plate PT100 I-

K Base plate AB270 V+

L Base plate AB270 V-


60

4 Reference

Table 10 Purple 10-pin seal nut on service turret

Pin Function

A Diagnostics

B Diagnostics

C Diagnostics

D Diagnostics

E Diagnostics

F Diagnostics

H Diagnostics

J Diagnostics

K Diagnostics

L Diagnostics

Table 11 Yellow 10-pin seal nut on service turret

Pin Function

A RPS1+Main switch+RPS2

B Main switch+RPS2

C RPS 2 only

D Switch common

E Z2 shim only

F Z0 and Z2 shim

H Magnet voltage V+

J Magnet voltage V-

K

L


Reference 4


Table 12 Red 10-pin seal nut on service turret

Pin Function

A Quench heater 1 V+

B Quench heater 1 & 2 common V-

C Quench heater 2 V+

D Quench heater 3 V+

E Quench heater 3 & 4 common V-

F Quench heater 4 V+

H

J

K

L

19-Way shim socket pin designations — 750/89/ASP

Figure 17 Pin arrangement in the 19-way connector on the shim lead


62

4 Reference

Figure 18 System connections for 750/89/ASP magnet


Reference 4


Table 13 Pin functions in the 19-way connector

Pin Function

A Z1 shim

B Z2 and Z0 shim

C X shim

D Y shim

E ZX shim

F ZY shim

G XY shim

H X2-Y2 shim

J switch heater common

K Main switch & RPS's

L Not Connected

M Z0 current -ve -

N

P Z0 current +ve +

R

S shim current -ve -

T

U shim current +ve +

V


64

4 Reference



5Agilent E5035 Nitrogen Monitor

Safety 66


Description and Operating Principle 68



Safety

66

Refer to accompanying documents.

WARNING Connect this equipment to an earthed mains supply. For continued protection against risk of fire or electric shock, replace fuses with the same type, rating and UL listing.

CAUTION Do not use this equipment in areas with flammable mixtures.


Agilent E5035 Nitrogen Monitor 5

Compliance Notice


Marking by the symbol indicates compliance of this device to the EMC (electromagnetic compatibility) and LV (low voltage) directives of the European Community. This unit is to be installed and operated as detailed. Any modification or maintenance procedure undertaken which is not approved by Agilent Technologies UK Ltd could nullify

the marking of this product and lead to prosecution. A 'Declaration Of Conformity' in accordance with the above directive has been made and is located at Agilent Technologies, Yarnton, Oxfordshire, UK.



Description and Operating Principle

68

Within the magnet nitrogen container, a capacitive probe controls the frequency of an oscillator built into the unit. Hardware measures frequency and a single seven segment display communicates results to the user.

When in use, the probe connector, upon which the unit mounts, must remain dry and free from any contamination or corrosion. This also applies to the connector mounted directly upon the unit itself.

Display

When in use, the display shows one of: E,1,2,3,4,5,6,7,8,9, F

where:

'E' represents a level below 5%.

'1' represents a level between 5% and 15%









'F' represents a level above 95%


Agilent E5035 Nitrogen Monitor 5

Calibration


When you press the calibrate button in the unit, the liquid level at this point is set as full. The calibrate button is visible through the small round hole in the red display filter. Use a slim, dull, insulated plastic object.

The calibration procedure takes about 5 seconds.

1 Press and hold the calibrate button.

The display changes to "C" which then disappears.

2 Continue holding the button until "C" reappears.

3 Release the calibrate button at this time.

The display of "C" changes to "F" shortly after the button is released.

There is no ill effect if the calibrate button is held pressed for longer; the result is the same.



Technical specification

70

Environmental conditions

The equipment is designed to be safe under the following conditions:

Use the E5035 only with the following cables:

The C0444010 cable contains a PSU unit which has an IEC320 inlet. The power requirements are 100- 240V AC 47- 63Hz 0.4A

The E5035H is a high field version which does not contain some internal power supplies which contain ferrites. This unit requires a different power supply unit. Only use this unit with the following cable:

The C0567010 cable contains a PSU unit which has an IEC320 inlet. The power requirements are 100- 240V AC 47- 63Hz 0.4A

Unit DimensionsLengthWidthHeight

98mm56mm44mm inc of connector

Weight 145 grams

Display 14mm (0.6 inch) 7 segment red LED

Ambient temperature range 10oC to 40oC

Relative humidity range 30% to 95% noncondensing

Atmospheric pressure 700 hPA to 1060 hPA

C0443120 Cable, E5035 Data/Power

C0444010 Cable, PSU E5035

C0567010 Cable, E5035H PSU



6Agilent E5080 Cryogen Monitor

Safety 72


Description and Specifications 74

Operation 78

Troubleshooting 82

Settings for Hyperterminal 87

Command Instruction Set 91

Connector Pin Assignments 96



Safety

WARNING Danger of electric shock. Isolate or disconnect from mains supply before opening this unit for any reason.

WARNING This equipment must be connected to an earthed mains supply. For continued protection against risk of fire or electric shock, replace fuses with the same type, rating and UL listing.

CAUTION This equipment is not suitable for, and must not be used in areas with flammable mixtures.

72

Clean the equipment case and front panel with a non- abrasive non- water based cleaner.

Store or install the equipment within the following environmental conditions:
Relative humidity range 30% to 95% noncondensing

Atmospheric pressure :700 hPA to 1060 hPA

The unit contains an internal lithium battery that should not be removed or changed other than by Agilent personnel.

There are no consumable parts associated with the instrument nor is there any preventative inspection or maintenance associated with the operation of the instrument.

There are no user maintainable parts within the instrument. Should the unit require repair, return it to Agilent Technolgies; see “Contact Information” on page 9.

Do not move the equipment after installation and connection to a magnet.


Agilent E5080 Cryogen Monitor 6

Compliance Notice


Marking by the symbol indicates compliance of this device to the EMC (electromagnetic compatibility) and LV (low voltage) directives of the European Community. This unit is to be installed and operated as detailed. Any modification or maintenance procedure undertaken which is not approved by Agilent Technologies UK Ltd could nullify

the marking of this product and lead to prosecution. A 'Declaration Of Conformity' in accordance with the above directive has been made and is located at Agilent Technologies, Yarnton, Oxfordshire, UK.



Description and Specifications

74

The E5080 unit is available in two configurations. These units are used to regulate the helium pressure within the cryostats of conventional twin cryogen cryostats (E5084) and refrigerated zero boiloff cryostats (E5083).

E5084 - pressure regulation for twin cryogen magnets

The twin cryogen cooled magnets are housed inside a helium reservoir, which is supported from the neck turrets on the top of the cryostat. These necks are in good thermal contact with the cold gas which boils off from the helium reservoir. Since the rate of cryogen boiloff inside a magnet cryostat is influenced by the local atmospheric pressure, the necks expand or contract a small amount when the pressure changes and the flow of helium gas through the necks changes. Since the magnet is hanging from these necks, it moves up and down a small amount relative to the bore of the cryostat.

For sites which experience large variations in atmospheric pressure, the small movement of the homogeneous volume with respect to the NMR sample volume can become apparent. You can overcome this effect by isolating the helium vessel from changes in atmospheric pressure, by piping exhaust helium gas through the E5084 unit. The E5084 actively regulates the flow of escaping helium gas so that the pressure is kept at a constant set level, typically a little higher than the maximum local pressure which will generally be experienced.




Figure 19 Schematic of E5084 system operation

E5083 - pressure regulation for refrigerated magnets

Refrigerated magnets are cooled electrically by a coldhead and compressor system. For zero boiloff magnets, the coldhead used will have sufficient cooling capacity to recondense helium gas as it boils off, plus additional capacity designed in for contingency.

The additional cooling capacity of the coldhead causes the He gas pressure within the helium can to be reduced below the ambient atmospheric pressure outside. Unless the system is manufactured completely vacuum tight this presents a risk of air being drawn into the helium can from outside.

The E5083 pressure regulator maintains a constant positive pressure in the helium can by controlling the current sent to a resistive element inside the cryostat. Heat generated by the resistor is actively regulated so that it balances the excess cooling power of the refrigerator.


76


Figure 20 Schematic of E5083 system operation



Technical specification


Environmental conditions

The equipment is designed to be safe within the following environmental conditions:

Mains input voltage 100 - 230V ~

Mains input power (max) 75 VA

Mains input frequency 50-60 Hz

Fuse Rating T2AH 250V absolute max

Gas port pressure 1150hPA absolute max

Gas Heater output voltageGas Heater output currentGas Heater output power

24V max:800mA max12W max

Isolated RS232 connection (9D socket)

9600 baud, 8 bits, 1 stop, and no parity.

Helium Probe Input Connector :9 way 'D' socket

Helium Probe resistance 0.2-0.05 /mm

The probe wire resistance varies from batch to batch. If the exact probe resistance is required, contact Agilent with the probe serial number.

Excitation current 80-245mA dependent upon probe wire resistance

Probe length 100mm to 2000mm

Thermal sensor input connections

9 way 'D' socket

Equipment classification Class 1


Relative humidity range 30% to 95% noncondensing

Atmospheric pressure 700 hPA to 1060 hPA



Operation

Overview

78

Information is shown to the user on a two line LCD display on the front of the unit. A 5- button keypad allows settings to be changed.

The three operations accessible via the front panel are:

• Adjustment of the helium gas working pressure

• Switch to a rapid sampling mode for use when liquid helium refill is taking place

• Mute the audio alarm signal

In normal operational, the display of data is static. In the event of an alarm or error condition, the display alternates between the normal display with the errors or alarms.

If for any reason the parameter displayed in the current part of the display cycle is out of tolerance or in error, the lower right hand part of the display shows the word "Error" and the red front panel LED is illuminated.

When the display is showing an error condition, an internal acoustic sounder sounds.

For more information relating to how the unit responds to errors, see “Troubleshooting” on page 82.



Connecting the E5080 to a magnet system


Connections are made via the magnet cables / gas pipe as required for the specific installation:

Do not connect any cables to "PRESSURE", "AUX INPUT", "RELAY OUT", or "LN2".

In E5084 mode, exhaust helium gas leaves the unit from gas port B and can optionally be routed through a floating ball flow gauge to give a visual indication of gas flow. You can also use this port to route gas into a helium recovery system.

Gas port C is used to measure the ambient atmospheric pressure. On earlier units, atmospheric pressure is measured directly within the enclosure of the unit.

Magnet E5084 E5083

Helium level cable Helium(Not required if magnet already has level monitoring fitted)

Helium

Helium gas pressure pipe

Gas port A Gas port A

Gas heater Not required Gas heater

Thermal sensor cable Not required Thermal

Figure 21 E5080 rear panel

The E5080 can measure the following items:

• Cryostat pressure

• Atmospheric pressure

• Helium level for two independent probes

• Thermal sensor reading for two independent sensors

• Gas flow rate (E5084 only)


80


The Helium level probes, thermal sensors may be enabled or disabled as required by the magnet system.

The parameter display screen shows the helium level (if level monitoring configured) and pressure of the helium vessel. The E5083 model also displays the thermal sensor temperature, the gas heater on time and an asterisk (*) if the gas heater is ON.

If you press the 'Right' key, the display shows the helium level for the secondary probe (if level monitoring is configured) and the current atmospheric pressure. The E5083 model also displays the secondary thermal sensor temperature.

Using the Menu System

CAUTION Other than to set the unit into Helium Fill Mode, do not change any parameters of the E5080 unit without first contacting Agilent. At the time of installation of the magnet, all parameters are correctly set by Agilent field representatives. Communicate any error condition indicated by the instrument to Agilent, who can advise you on the correct remedial action.

Figure 22 E5080 front panel

When in the menu system, Up and Down buttons move between menu items.

Left and Right buttons adjust the value.

Center/Enter applies the value.

If an entry is left incomplete or the menu system is not exited, a time- out of approximately one minute occurs.




To adjust the pressure

• Press Center/Enter then Down. Press Left/Right to alter the value.

• Unit is mB and the step size is 1mB.

• When the operating pressure is adjusted via the front panel, an automatic adjustment is also made to the upper and lower pressure alarm settings. These are set 5 mB above and below the operating pressure.

To change the Helium Fill mode

• Press Center/Enter then Down, Down, Center/Enter. Press Left/Right to alter the state.

• This procedure turns On or Off the fast sample action which occurs about every 40 seconds as required when helium filling.

• This has a 90- minute time out period after which normal samples on an eight hour basis occur.

To mute an audible alarm condition

• To silence the audible alarm while it is active, press the front panel down arrow key pad.

• Hold the key pressed for approximately five seconds and release it.

• The sounder is then silenced.

• A message is automatically added to the Error Message stream as displayed on the LCD screen, to the effect that the audible alarm is muted.

• When the alarm situation is corrected, the mute is automatically reset to Off, thus enabling any subsequent audible alarm.



Troubleshooting

82

This section contains descriptions of some common problems to help the Installation Engineer to find the source of the problem and ensure the proper operation of the unit.

Problems that occur on E5084 and E5083 units

Problem As detected by E5084/3 Alarm result Comments

Disconnected helium cable

Helium hardware error Helium hardware failure is detected

Detected one second after a helium read is attempted

Open or disconnected gas pipe

Pressure same or close to atmospheric

Falling helium level

Low pressure alarm very likely

Helium low alarm, later

Within three seconds

Blocked gas pipe Pressure may be affected

Measured helium pressure does not rise

Likely that a pressure error is triggered



Problems that occur on E5084 unit only


Problem As detected by E5084 Alarm result Comments

Low helium gas flow Flow may fall below low flow trip level.

Error LED is illuminated.

"Flow low" message appears on screen.

Low flow may be indicative of a gas leak. This must be investigated.

IMay occur legitimately directly post-helium fill.

High helium gas flow Flow may rise above high flow level.

Error LED is illuminated.

"Flow high" message appears on screen.

High flow may indicate magnet problems and should be investigated with urgency.

Zero flow Flow falls below low flow trip level.

"Zero flow" message appears on screen.

May occur legitimately directly post-helium fill.



Problems that occur on E5083 unit only

84


Slow helium leak to atmosphere

Falling helium level.Apparent increase in cooler efficiency.

Low helium levelbut not immediately.Pressure may be correct, initially.

After a period of days or weeks.

Gas heater activity may well appear to be normal but in fact will be slightly more active.

Fast helium leak to atmosphere

Falling helium level, quite soon.

Inability to maintain pressure

Low helium level, sooner rather than later.

pressure likely to fall below alarm point

Period of hours or few days.

Gas heater likely to be on 100% time.

Failed gas heater resistive element, open circuit.

Hardware failure of gas heater

Heater hardware failure is detected status shows " ERROR "

Within three seconds, if and only if the heater should be active

Failed thermal sensor - open circuit

Thermal hardware error. Thermal hardware failure is detected

Within three seconds if and only if the thermal sensor should be active

Cooler failed or low efficiency.

Pressure rises

Thermal reading may rise

Over pressure alarm may be tripped if rise is sufficient.

Over temperature may be tripped

Status changes to " ERROR " when any one of the factors over-steps the trip level.

Gas heater will usually be off 100% time, if cooler has failed

Disconnected thermal sensor cable

Thermal sensor hardware failure is detected

Thermal sensor hardware failure is indicated.

Within three seconds

Disconnected gas heater

Hardware failure of gas heater

Heater hardware failure is indicated.

Within three seconds after E5083 commands gas heater " ON "



Burst disc, burst. Burst disc sensor detected as burst

Pressure will fall

Likely that a pressure error is triggered

Magnet may have quenched

Disconnected burst disc or open circuit cable

As above

Non cycling gas heater

Gas heater fixed on or off for longer than about 2 hours, and has not cycled on - off in that time

May be a helium leak if the heater is on for a long period.

May be lack of cooling efficiency if the heater is off for a long period

Can occur post helium fill, prior to re-pressurizing or during installation phase

Cryo-cooler low efficiency

A cooler on to off ratio that exceeds the set alarm level

Alarm LED active, sounder active, if not muted.


750/89 Premium Shielded High Resolution NMR Magnet System Overview 85


Helium probe hardware errors

86

The E5080 tests the continuity of the heater current path within the helium probes only when a particular probe is active.

Normally the helium liquid level is measured three times per day, at 01:00 hrs, at 09:00 hrs and at 17:00 hrs, all being with respect to the internal real- time clock of the unit. If a hardware error is detected, it is stored and will be displayed as an error message indicating a helium probe hardware error, together with which channel is in error. This error will not be cancelled until the next level measurement is made, 8 hours later. This does not apply when the unit is operating in helium fill mode, during which time the probe(s) is tested every read, being approximately at one minute intervals.

Thermal sensor hardware errors

The E5080 tests the continuity of the thermal sensors during each measurement cycle, for example, every three or so seconds. If when tested, a hardware error is detected, it is stored and is displayed as an error message indicating a thermal probe hardware error, together with which channel is in error.

Gas Heater hardware error

The E5083 tests the continuity of the gas heater resistive element every few seconds when the heater is energized. During a period when the heater is off, a fault is not detected until the heater is next energized.

In normal use the gas heater cycles continuously and changes state On to Off several times during an hour.



Settings for Hyperterminal


You can configure a number of advanced settings by connecting to the E5080 unit over a serial link. Adjustments to these settings can be made by an Agilent engineer during system installation. Do not change these settings during normal operation without prior approval from Agilent.



To make advanced settings

88

1 Click File > Properties to access parameters to control HyperTerminal.

2 On the Connect To tab, select the appropriate COM channel number. COM2 is shown below. You may need to use COM1, COM2 or COM3.

3 On the first screen, click Configure to display the COM Properties screen, shown on the right below.

4 Set the COM parameters and click OK.




5 On the Settings tab, click ASCII Setup, to display the ASCII Setup screen, shown on the right below.

6 Set the ASCII parameters and click OK.

To make serial cable pin connections

Connect only the pins shown in the table below.

E5083M 9 way skt PC 9 way skt

pin 2 pin 2

pin 3 pin 3

pin 5 pin 5



Using Hyperterminal to upload logged data

90

1 Connect laptop or other PC to E5080, then run Hyperterminal.

2 Click Transfer, select Capture Text.

3 Use browse to find a suitable log location and enter a file name.

4 Click Start in the same general dialog box.

5 Type R, <RETURN> to upload the logged data.

6 When the log upload has ended:

a Click Transfer.

b Select Capture Text.

c Click Stop in the same dialog box.

7 To view the data, use an appropriate spreadsheet program.



Command Instruction Set


Note the following guidelines:

• All commands are terminated with CRLF (that is, press the Enter key).

• All command letters are case- sensitive.

• Back- spacing is not allowed.

General commands

Command Function

A Turn Sounder On if error exists

K Turn Sounder Off if error exists

ynn Set year (00 to 99)

Mnn Set Month (0 to 12)

Dnn Set Date (0 to 31)

dn Set Day (1=Sun, 2=Mon, 3=Tue, 4=Wed, 5=Thu,6=Fri,7=Sat

hnn Set hours (0 to 23)

mnn Set minutes (0 to 59)

snn Set seconds (0 to 59)

BDY Enable Burst Disk

BDN Disable Burst Disk

r Restart software



Helium commands

92

Command Function

P1Y Switch Probe 1 On

P1N Switch probe 1 Off

P2Y Switch Probe 2 On

P2N Switch probe 2 Off

PL1nnnn Set Probe Active length where nnnn is length in mm including leading zeroes

H1Lnnnn Set Helium Alarm level where nnnn is length in mm including leading zeroes

H1Tnnn Set Heater time where nnn is time in secs including leading zeroes

H1Cnnn Set Heater Current where nnn is current in mA including leading zeroes

PR1nnnmm Set Probe Resistivity where nnn.mm is resistivity in ohms/m including leading zeroes

PL2nnnn Set Probe Active length where nnnn is length in mm including leading zeroes

H2Lnnnn Set Helium Alarm level where nnnn is length in mm including leading zeroes

H2Tnnn Set Heater time where nnn is time in secs including leading zeroes

H2Cnnn Set Heater Current where nnn is current in mA including leading zeroes

PR2nnnmm Set Probe Resistivity where nnn.mm is resistivity in ohms/m including leading zeroes

HMY Set Helium Fill mode On

HMN Set Helium Fill mode Off

HN Read Helium level



Thermal channel commands


Command Function

XIY Switch Thermal channel A on

X1N Switch Thermal channel A off

X2Y Switch Thermal channel B on

X2N Switch Thermal channel B off

CNAnn Set number of entries in thermal sensor data table channel A to nn+1

CNBnn Set number of entries in thermal sensor data table channel B to nn+1

T1xxy Set thermal channel A alarm level where xx.y is in degs K,

T2xxy Set thermal channel B alarm level where xx.y is in degs K,

CEAnnkkkRRRRR Set thermal sensor table A entrywhere nn is table index value starting from 00

For software versions 1 to 4 where kkk is x.xx degs K

For software versions 5 onward where kkk is xx.x degs K

where RRRRR is Ohms with leading zeroes

CEBnnkkkRRRRR Set thermal sensor table B entrywhere nn is table index value starting from 00

For software versions 1 to 4 where kkk is x.xx degs K

For software versions 5 onward where kkk is xx.x degs K

where RRRRR is Ohms with leading zeroes



Pressure commands

94

Command Function

pnnnn Set required pressure in mB

HPnnnn Set high pressure alarm in mB

LPnnnn Set low pressure alarm in mB

Gas flow (E5084 only)

Command Function

FHnnn Sets the E5084 high level flow alarm value in cc/hr liquid He

FLnnn Sets the E5084 Low level flow alarm value in cc/hr liquid He

Gas heater (E5083 only)

Command Function

CLnn [00..99] Gas Heater Alarm lower limitPlease note that a CL00 will turn OFF the cryo-cooler alarm function.



Request command


N.B. for early single thermal channel version use CT, CE, and CN.

Command Function Reply

? List Help Text String displaying Command Set

t Display Clock Text String indicating Date and Time

W Read Parameters Concise

Text String of parameters

U Read Parameters Verbose

Text String of parameters

R Read log Tab delimited file of log entries

EH Read errors List of errors

CTA Read Thermal sensor data table Channel A

List of Table entries

CTB Read Thermal sensor data table Channel B

List of Table entries



Connector Pin Assignments

96

9D Skt Temperature Sensor

2 Sensor 1 +V

3 Sensor 2+V

4 Sensor 1 +I

5 Sensor 2 +I

6 Sensor 1 -V

7 Sensor 2 -V

8 Sensor 1 -I

9 Sensor 2 -I

3 Pin DIN Skt Heater

1 +V

3 -V

25D Skt Alarm Relay

14 Common 1

1 Normally Open 1

2 Normally Closed 1

3 Common 2

15 Normally Open 2

16 Normally Closed 2

Maximum contact rating 30Vdc/1A



6 Pin DIN Skt Aux

6 Burst Disc +V

2 Burst Disc -V



98



Agilent 750/89 Premium Shielded High-Resolution NMR Magnet SystemSystem Overview

7Technical Specifications

System Description 100

The Superconducting Magnet 101

The Cryostat 103

Customer Interface Drawings 106

System Components 111



System Description

100

The 750/89/ASP magnet uses Agilent’s Premium Shielded magnet technology which features outstanding fringe field containment to minimize laboratory space requirements.

External field perturbations are efficiently attenuated. Pneumatic antivibration support legs are supplied as standard across the product line to allow siting in a wide range of environments.


Technical Specifications 7

The Superconducting Magnet

General description


The magnet is wound from a combination of multifilamentary NbTi and Nb3Sn conductor. The windings are placed on precision machined formers and then fully vacuum impregnated for robustness and long- term reliability.

The magnet is designed to exacting standards of homogeneity. The use of proprietary jointing techniques both for NbTi and Nb3Sn materials ensures the very best field stability.

The magnet coils are fully protected from accidental damage due to a magnet quench by a passive resistor network located within the helium reservoir.

The magnet is designed to conservative levels of stress and mechanical stability to ensure reliable and stable operation. In addition, the use of high quality superconducting wire ensures that a top quality system is delivered.

Magnet specifications

Table 14 Magnet specifications

Magnet type Compensated self-screened solenoid

Central field (4.2K operation) 17.6 Tesla (750 MHz 1H)

Field stability (4.2K operation) Less than 0.014 ppm/hour drift (10 Hz/hour 1H)

Operating current 263 Amps (nominal)

Typical time to energize magnet to full field

Less than 48 hours (including pauses)

Stored energy 5.5 MJ

Fringe field* (5 gauss line) 1.60m radially and 2.55m axially

Fringe field shown on Customer Interface Drawing


102


Superconducting shim coils

WARNING * In the event of a quench, it is possible for the magnetic field to bloom beyond this limit momentarily. For further details, consult the document Safety Considerations for the Installation and Operation of Magnet Systems.

These coils are positioned on a separate former surrounding the main coil in the helium reservoir. Each coil set is fitted with a superconducting switch for persistent mode operation.

Table 15 Coil details

Shims provided Z0, Z1, Z2, X, Y, ZX, ZY, XY, X2-Y2

Coupling All shims (apart from Z0) are designed to be decoupled from main coil

Orthogonality All shims are designed to be fully orthogonal

'X' axis alignment Nominally coincident with the service turret



The Cryostat

General description


The cryostat is of conventional design, consisting of a central all- welded stainless- steel helium vessel surrounded by a gas cooled radiation shield and liquid nitrogen reservoir. The complete assembly is contained within a stainless- steel outer vacuum vessel with a service turret on top of the cryostat. The turret provides access to the helium reservoir for the demountable magnet leads, helium level probe, and helium transfer siphon. The outer vessel has a bottom- flange closure constructed from aluminum which is sealed to the main body and bore- tube by a compressed o- ring seal.

The cryostat is supplied with a support stand that consists of antivibration legs with load spreading plates at the bottom which have provision for fixing to the floor of the installation room. If the magnet will be installed within a seismic zone, then seismic bracing is supplied (suitable for up to and including Seismic Zone 4).

The helium reservoir contains in total approximately 925 liters of liquid helium of which a volume of approximately 260 liters is above the level of the superconducting joints. It is recommended that while the system is in operation the superconducting joints, which are mounted above the main coil windings, are only partially nonimmersed in liquid helium. Details of refill intervals are given in the following sections.

Cryogen level monitors are incorporated into both the liquid helium and liquid nitrogen vessels and the associated electronics provide liquid level display and low- level alarms.

Cryostat specifications

The cryostat is generally as shown in accompanying drawing no. ANZ341275, issue D (Figure 23 on page 106). The drawing shows the standard system (without seismic bracing). Full specifications for the system are given in the following tables.


104


Finish

Dimensions

Table 16 Cryostat finish

Cryostat Light gray (RAL 7047), semigloss

Antivibration legs Charcoal gray (RAL 7011) semigloss

Leg hoods Charcoal gray (RAL 7011) semigloss

Table 17 Cryostat dimensions

Length of bore of cryostat 1858 ±3 mm

Height of system without legs 2213 mm

Floor to base of bottom plate 877 mm (900 mm to closure flange)

Height including 1468 mm legs 3090 mm

Diameter of cryostat including base flange

1495 mm

Room temperature clear bore (without shims)

89 mm

Room temperature bore-tube material

Copper

Center of field to bottom closure flange

520 5 mm

Minimum ceiling heights with 900 mm system height from floor:

For standard helium siphon 3915 mm

Standard helium siphon, hinged installation tools

3855 mm

Split helium siphon and hinged installation tools

3610 mm

System weights:

Magnet in cryostat 3,750 kg (approximately)

Cryogens (when full) 350 kg (approximately)

Antivibration legs (and optional seismic bracing)

300 kg (approximately)

Shipping information:

Crate 1 dimensions (magnet and ancillaries)

192 182 x 240 (h) cm 4,000 kg (approximately)




Liquid helium cryogen details

Liquid nitrogen cryogen details

Crate 2 dimensions (antivibration legs)

122 x 122 x 158 (h) cm320 kg (approximately)

Table 18 Liquid helium cryogen

Siphon leg diameter 0.5" (12.7 mm)

Helium required for installation:

(a) Cooling magnet to 4.2K after nitrogen precool, filling helium reservoir, and helium top-ups during installation

3,000 liters (estimated)

(b) Standby volume per training quench

1,000 liters

Volume of helium reservoir 925 liters

Recommended refill volume during normal operation

260 liters (nominal)

Hold-time during normal operation (static magnetic field, leads withdrawn)

Greater than 120 days

Table 19 Liquid nitrogen cryogen

Total volume of nitrogen required for installation

4,000 liters (estimated)

Volume of nitrogen reservoir 250 liters (approximately)

Refill volume 220 liters

Hold-time in static condition Greater than 21 days

Table 17 Cryostat dimensions



Customer Interface Drawings

106

Figure 23 ANZ341275D drawing 1 of 5






108








110





System Components

Superconducting magnet system components


Table 20 Magnet system components

1 ea. MRCA 750/89/ASP magnet system

1 set Antivibration legs (with seismic bracing where required)

Standard ancillary parts provided with the system

Table 21 Standard ancillary parts

1 set Transit fittings

1 set Helium and nitrogen level probes

1 ea. E5082 combined He level monitor, He gas flow meter, and pressure controller

1 ea. E5035 digital head oscillator unit, service cable, and PSU

1 set Helium transfer siphon and extension tube

1 ea. Helium fill adapter, seal nut, washer, and o- rings

1 set Transfer siphon maintenance parts

1 ea. Nitrogen transfer line (5m) and nitrogen turret fitting

1 ea. 1.65 m Dipstick for helium supply Dewar

1 ea. System manual

1 ea. Packing crate

Required (not included in standard scope of supply)

Table 22 Required parts not supplied with standard system

Platform for access to top of magnet

Site pipe work to channel gas from magnet quench duct to outside

NOTE Agilent RT shims are supplied as part of the complete NMR spectrometer system and are described in a separate technical specification document.


112



Agilent Technologies

© Agilent Technologies, Inc.

Printed in USA, October 2012

*9100381100*

9100381100

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