Safety aspects in Particle · PDF filenitrogen capture line at 10.86 MeV was identified in ......

Safety aspects in Particle Accelerator

Pramod V Bhagwat Head, Ion Accelerator Development Division

BARC

23-11-2016 33rd DAE Safety & Occupational Professionals Meet AERB & IPR, 23-25 Nov 2016

Outline

• Type of Accelerators

• Accelerators in BARC

• Radiological Safety aspects

• Safety aspects of Non-ionizing radiation

• Safety framework in BARC

23.11.2016 33rd DAE Safety & Occupational Professionals Meet

AERB & IPR, 23-25 Nov 2016

• Broadly particle accelerators are classified to the following categories..

– Electrostatic or DC Accelerator

– RF Accelerator

– Synchrotron or storage rings


AERB & IPR, 23-25 Nov 2016

I. Pelletron-Linac facility, NPD at TIFR II. Medical cyclotron, RMC, Parel III. 6 MV Folded Tandem Accelerator (FOTIA), IADD IV. Tandetron at NCCCM, Hyderabad V. 14 MeV Neutron Generator, NXPD VI. 7 MeV Linac, Radiation & Photochemistry Division VII. ILU-EBA (5 MeV, 15 kW) VIII. 500 KeV, Electron accelerator, APPD, BRIT, Vashi IX. 3 MeV electron Linac, Electron Beam Centre, Kharghar X. 10 MeV electron Linac, Electron Beam Centre, Kharghar XI. Electron Cyclotron Resonance Ion source at 100 kV, NPD XII. 20 Mev Proton Accelerator, IADD

23.11.2016

Accelerators in BARC

33rd DAE Safety & Occupational Professionals Meet AERB & IPR, 23-25 Nov 2016

23.11.2016

Sir John Douglas Cockcroft was a British Physicist. He shared the Noble Prize in Physics for splitting the atomic nucleus with Ernest Walton. Ernest Thomos Sinton Walton was an Irish Physicist and Noble Lauraete for his work with John Cockfrcroft with “atom-smashing” experiments done at Cambridge University in the early 1930s.

First high voltage generator

7Li + p 4He +4 He and 7Li + p 7Be + n.

at 400 keV, first nuclear reactions; Nobel prize 1951.

(27 May 1897-18 September 1967)

( 6 October 1903- 25 June 1995)


The charge particle accelerators are being increasingly used, both directly and indirectly, for research in many frontier areas of science. They are also indispensable for varied applications ranging from materials science to medicine and, more recently, even for radioactive-waste transmutation and energy production. In early sixties a 1 MV Cascade generator was installed at TIFR .

23.11.2016

Cascade Generator

Dr H J Bhabha in front of Cascade Generator


Disadvantages: •These belts suffered from a number of operational difficulties including terminal voltage instability and susceptibility to spark damage. •Generated belt dust necessitating frequent cleaning inside the accelerator tank.

• The belt is electrically charged by a brush or comb.

• The charge can be negative or positive depending on the polarity of the source

• The resulting terminal voltage is a function of the diameter of the terminal electrode

• In order to achieve higher voltages the Van de Graaff accelerator is enclosed in a high pressure vessel (SF6 or mixture of N2 (80%) and CO2 (20%).

(December 20, 1901- January 16, 1967)

Van de Graaff Generator


• Model 14 UD from NEC, USA

• Column voltage rating 15 MV

• Tube voltage rating 14 MV

• Voltage stability ± 2 kV

• Proton energy range 8 to 28 MeV

• Heavy ion energy range 4(n+1) to 14(n+1)MeV

• Test current values

Protons 3-5 µamps.

Alphas 2 µamps.

Heavy ions 100 ηA particle

Specifications of Pelletron

23.11.2016

Raymond George Herb 22-01-1908 – 01-10-1996

Pelletron –Linac Facility


Column voltage rating 6MV Voltage stability ± 2 kV Heavy ion energy range: 1(n+1) to 5(n+1) MeV Proton energy range 1 to 5 MeV

23.11.2016

Specifications

A schematic diagram of Folded Tandem Ion Accelerator

Folded Tandem Accelerator


The 5.5 MV single ended Van-de-graaff accelerator was converted into a 6 MV folded heavy ion accelerator using NEC accelerating tubes and column. The negative ions are generated by a SNICS source floating at -200 kV deck potential and then bend by 900 using a combination of electrostatic deflector (200) and injector magnet (700). The ion beam in the terminal is bend by a 1800 magnet after the stripper. The power to the folding magnet and various electronic devices in the terminal is given by a 5 kVA alternator, operating at 400 Hz, specially designed for this purpose. The alternator rotates at 1500 rpm and driven by a segmented Perspex shaft. The accelerator is operational since 2000 and routinely used for various

applications.

23.11.2016

Folded Tandem Accelerator


•

-ve ions

+ve ions



23.11.2016 33rd DAE Safety & Occupational

Professionals Meet

Pelletron Accelerator


Positive Ion Injector Schematic


23.11.2016

Available Energy Range


PK-ISIS Set Up - I


U beam spectrum


Medical cyclotron, RMC, Parel

23.11.2016

The 16.5 MeV cyclotron was installed in 2002 at Radiation Medicine Centre, Parel and since then it has been operational. This accelerator has given exceptional service to the society and a large number of patients have been treated so far. Negative H ion is accelerated to 16.5 MeV and bombarded on enriched water (H2O18). Thus, 18F is formed which has a half-life of 110 min. FDG is produced for in-house use and supply to other hospitals. Over 60 patient doses prepared daily at < Rs. 5000 per dose. [F-18]NaF, [F-18]FLT and [F-18]FMISO are also produced routinely.

Medical Cyclotron


The Tandetron accelerator (3 MV) was installed and commissioned in 1995 with a minimal self-sufficient configuration. The main accelerator consists of a dual ion source injection system with a 900 analysing magnet, a 3 MV high voltage terminal system with a stability of ± 300 V, an analysing magnet at high energy end with 5 port switching magnet chamber supported by an electrical quadruple triplet lens and other beam handling system. The beauty of this accelerator is that after its installation, the tank was opened only once for servicing. Typical applications of this accelerator are depth profiling of light elements ( H, Li, B, Al, Mg) by nuclear reaction analysis, compositional analysis and thickness determination by RBS, elemental analysis of bulk material by PIXE and PIGE etc.

23.11.2016

3 MV Tandetron Accelerator



Professionals Meet

3 MV Tandetron Accelerator


This accelerator is a Cockroft-Walton type and generates +300 kV. Radio Frequency (RF) ion source can accelerate H+ or D+ ions. The accelerated ions at 300 KeV, when bombarded on a target which consists of Deuterium/Tritium absorbed in Titanium on a 1 mm thick and 30 mm dia. Copper disk, generates 14 MeV Neutrons. The accelerator is being used for Neutron radiography, Fissile material Detection, Prompt capture gamma experiments. Using BGO detectors nitrogen capture line at 10.86 MeV was identified in Urea, Chlorine and other elements. Recently, accelerator was coupled to an ADS experimental set-up.


Professionals Meet

14 Mev Neutron Generator


Professionals Meet

Experimental Thermal ADS - BRAHMMA

14 Mev Neutron Generator

Research Activities [1] Radiation Chemistry in nuclear energy systems Current nuclear fuel cycle requires investigations of the

fundamental chemical processes resulting from intense radiation,

high temperatures and extremes of redox potential and high

acidity. These information are needed to understand: Coolant behaviour Gas generation in the core Corrosion behavior of the core materials Extractants for the targeted separation processes Storage materials for nuclear waste Chemical decontamination formulations

[2] Development of efficient antioxidant and radio-protectors

[3] Nanomaterials research

Synthesis of metallic and semiconductor nanomaterials Tuning of surface properties, opto-electronic, magnetic

properties Behaviour of device materials like semiconductor

nanomaterials, LCD etc at high radiation doses

[4] Investigation of radiation effect in biological systems

A technique which works in interdisciplinary areas of Radiation

and Photochemistry.

7 MEV LINAC, RADIATION & PHOTOCHEMISTRY DIVISION

23.11.2016

Radiolysis facility which is based on 7 MeV Linac was procured from M/s Radiation Dynamics, UK and commissioned in 1986. Since then it is providing trouble-free service and main work horse of RPCD. The electron energy spread is ± 0.4 MeV and operates at 3000 MHz. The electron beam is available at 25, 50, 100, 200, 500 and 2000 nsec pulse width and corresponding peak current at 900, 400, 200, 150, 90 and 70 mA. In a collaborative effort with Laser Electronic Support Division, (LESD) of RRCAT, a new pulse slicer unit has been developed to generate continuously tunable pulses right from 1 microsecond down to 30 ns duration. The facility has wide applications mainly radiation Chemistry in nuclear energy systems, development of efficient antioxidant and radio-protectors, Nanomaterials research and investigation of radiation effect in biological systems.

7 Mev Linac


23.11.2016

ILU-EBA (5 MEV, 15 KW)

The 2 MeV electron beam accelerator has been successfully functioning since 2001 at BARC-BRIT complex, Navi Mumbai. This facility comprises of an electron beam machine which is a cavity resonator type, RF pulse accelerator with electron beam energy 2 MeV and current 10 mA with a scanning width of 900 mm. A power roller conveyor system has been installed to transport the material in & out of the irradiation cell area and a linear conveyor for transporting the material to & fro so that desired dose can be delivered to the product. Among the applications of this accelerator Polymer processing (crosslinking of PE O-rings, cable insulations, heat shrinkable materials, tyre components etc), Diamond colour enhancement and Waste water treatment (on pilot scale) are important one. Recently this accelerator was upgraded to ILU-EBA (5MeV/15kW). Its application in low dose (0.25 kGy to 1.0 kGy) includes disinfection of packed powders, cereals, grains, Fish, Meat (in cold condition) etc, in medium dose (1.0kGy -30kGy) Medical products Sterilization, Polymer material etc and on high dose Polymer crosslinking & degradation- O-rings, HS components; thick polymer samples; Semi-Precious stones etc.

2 Mev Electron Linac


Industrial Applications of Electron Beam

Application Energy Dose (kGy)

Cross Linking of Polyethylene 0.3-10 MeV 50-300

Thermo Shrinkable Plastics 0.5-4 100-250

Teflon Degradation 2

Curing of Coatings on wood 0.15-0.5 20-500

Exotic Colors in Diamonds 2-10 few MGy

Sewage & Sludge Treatment 0.5-4 0.5-1.0

Food Preservation 5-10 5-10

Disinfestation of Grain 1 0.5-1.0

Purification of Exhaust Gases 0.3-1.5 10-15

Sterilization of Medical Prods 1-10 20-50

Vulcanization of Rubber 0.5-1.5 20-500

Graft polymerization 0.3-2.5 10-300 1 Gy = 1 J/kg = 100 rad

23.11.2016

Product Conveyor e-beam

Now upgraded to 5 MeV energy

2 Mev Linac / 20 kW pulse



Professionals Meet

Prospects for industrial applications using upgraded ILU-EBA (5MeV/15kW)

LOW DOSE (0.25kGy to 1.0kGy)

Disinfection of packed powders, cereals, grains;

Fish, Meat (in cold condition);

MEDIUM DOSE (1.0kGy -30kGy)

Medical products Sterilization; Polymer materials;

HIGH DOSE

Polymer crosslinking & degradation- O-rings, HS components; thick polymer samples; Semi-Precious stones



23.11.2016

Type : ILU-6 Resonator Cavity, pulse 2 MeV/20 kW , scan width: ~100cm ;

single window / four window Linear scanning



23.11.2016

Electron accelerators in the energy range of 200 to 800 KeV are used for various industrial applications like plastic modifications, surface treatment and irradiation of medical products. 500 KeV Electron Accelerator mainly consists of EHV supply, electron beam system, accelerator tank, computer control system, vacuum system, radiation shield and product handling system. The accelerating column consists of three modules of large gradient metal-ceramic tubes which can deliver beam up to 20 mA. The electron gun is triode geometry and uses LaB6 Cathode.

500 keV, Electron Accelerator

3 MeV DC ACCELERATOR SCHEMATIC

3 MV supply is based on parallel fed

voltage multiplier scheme

Trial Operation of the accelerator up to 1.5

Mev, 10 kW has been conducted

3 Mev Electron Accelerator

30

3 Mev Electron Accelerator


20 MeV

3 MeV

200 MeV 1 GeV

ADS PROGRAMME OVERVIEW

Demo ADS

Facility

IIFC

collaboration

Radiological safety aspects Target limit

Public 1 mSv/year

Radiation worker 30 mSv/year 100 mSv/5 years

BSC

OPSRC

DSRC ULSC-PA LSC

• Ionizing Radiation – Prompt (Vanishes with the switching off

or stoppage of the projectiles before it gained energy)

– Residual (induced activity and the resulting gamma)

– Silent • X-rays from high voltage units, klystrons • Any device with a high voltage & higher

order vacuum

• Non-Ionizing radiation – Microwave, RF

• Toxic, NOxious gas production • Interlocks, search and secure system,

scram etc

1. Pelletron-linac TIFR 2. FOTIA BARC 3. Medical Cyclotron Facility RMC 4. CCCM-Hyderabad 5. ILU Vashi 6. 500keV Vashi 7. 7MeV e- BARC 8. Neutron Generator Purnima BARC 33rd DAE Safety & Occupational Professionals Meet

AERB & IPR, 23-25 Nov 2016

Radiations from particle accelerators Prompt

Radiation

Positive ion

Gamma Neutrons

X –rays Muons, pions

Electron

Photo neutrons Bremsstrahlung

Solid gas

Muon, pions

Residual radiation


Radiation Safety Systems

Personnel protection systems

Zoning and shielding

Search & Secure

SCRAM Door

Interlocks

Audio-Visual alarms,

CCTV

Radiation monitoring systems

Area Monitoring

Beam loss

Hand held survey

Personal monitoring

TLD Neutron

DRD

Fixed


Interlocks

Search and

Secure

Doors locked

Hooter and flash

Door key returned

Wait for 60-90

seconds

Interlock activated

Beam on

Door opened?

Trapped ?

SCRAM

High Radiation ?

Stop beam

Safety Organization

ACCELERATOR REGULATION IN BARC

1 December 2016 Short term course on Particle Accelerators

in BARC 37

DSRC- AP

OPSRC

ULSC-Particle Accelerator

BARC Safety Council

Design Stage Accelerators Operational Accelerators

Working Groups

RADIATION SHIELDING

Passive protection against the radiation due to

•Bremsstrahlung radiation from electron machine

•Characteristic X rays

•Photo neutrons produced inside the target and shield

•Neutrons produced due to accelerated particle /

secondary beam particles.

•Prompt gamma rays due to interaction of ions or

neutrons

Shielding design to confirm 1 µSv /h for full occupancy area.

Annual Dose limit for occupational worker – 20 mSv/year

averaged over 5 years

1 December 2016 33rd DAE Safety & Occupational Professionals Meet

AERB & IPR, 23-25 Nov 2016

INDUSTRIAL SAFETY AND OCCUPATIONAL HEALTH

Industrial safety and occupational Health

Governed by

Factories Act, 1948

Atomic Energy (Factories) Rules, 1996

•First aid, periodic medical examination,

•Noise Pollution

•Appropriate lighting

•Pressure vessels, vacuum systems

•Fork lifts, hoists, cranes

•Moving machineries

1 December 2016 33rd DAE Safety & Occupational Professionals Meet

AERB & IPR, 23-25 Nov 2016

Electrical Safety High voltage interlocks, barriers, grounded cages

Caution Signs

High quality earthing ( resistance < 1 ohm)

Provision of grounding rods

High quality insulating mats

Ventilation

Ozone production in EBA (safe limit 0.1 ppm)

Noxious fumes and gases

Air borne radionuclide such as 7BE, 15O, 13N , 41Ar

SF6 gas monitoring. Oxygen deficiency monitors should be

installed.

1 December 2016 Short term course on Particle Accelerators

in BARC 40


Cryogenics

Liquid helium and Liquid nitrogen are used for

cooling superconducting magnets, RF cavity.

Extreme cold can cause tissue damage, can change the properties of material.

Asphyxiation may occur due to accidental release.

Oxygen deficiency monitors should be provided.

Proper training for handling cryogenic liquids with proper PPE is necessary.


AERB & IPR, 23-25 Nov 2016

Safety aspects of Non-ionizing radiation

• Non-ionizing radiation (3kHz-300 GHz) is used in many accelerator facilities. The

most commonly used primary sources are vacuum tubes, klystrons, magnetrons,

backward wave oscillators and solid-state RF devices. These are used to generate

Electric field/Magnetic field/Electromagnetic fields (E-field/H-field/EMF) according to

the application. While E-fields are primarily responsible for acceleration, H-fields are

used for beam manipulation (bending, focussing, scanning, etc).

• For most accelerator installations, high performance and safety are mutually

reinforcing goals. Both human safety and equipment safety aspects should be

considered during design stage of the accelerator and its sub-systems. Health risks

associated with exposure to non-ionizing radiation-fields have been established for

various frequency ranges.

• Exposure to occupational workers and general public are to be considered while

evaluating the safety aspects for non-ionizing radiation.

23.11.2016


To avoid exposure to persons to unacceptable levels of non-ionizing radiation, engineered and administrative controls,

personal protection programs, and medical surveillance should be adopted. As a first step, engineering controls should

be undertaken wherever possible to reduce device emissions of fields to acceptable levels. Such controls include good

safety design and, where necessary, the use of interlocks or similar health protection mechanisms. Some of the

measures are listed below:

• Suitable features to minimize radiated and conducted emission in RF & Non-RF instrumentation should be

adopted from design stage itself

• Proper shielding techniques for E/H/EM fields should be used

• Suitable grounding schemes (with isolation between DC & RF, if necessary) should be incorporated to minimize

leakage of non-ionizing radiation.

• Suitable grounded enclosures should be used for both RF and non-RF instrumentation

• Compliance to relevant standards for radiated emission (RE) and conducted emission (CE) should be ensured

• Proper gaskets to prevent leakages from waveguide/other joints should be used

• Proper terminations (with matched RF Loads) should be used

• Administrative controls, should be used in conjunction with engineering controls for ensuring safety. This includes

•

• Proper access control

• Display of appropriate caution boards at appropriate locations

• Use of audible warning systems, wherever necessary

• RF leakages tests, (periodic/continuous) interlocked to machine operation, should be incorporated if necessary


AERB & IPR, 23-25 Nov 2016

Administrative controls, should be used in conjunction with engineering controls for

ensuring safety. This includes

• Proper access control

• Display of aappropriate caution boards at appropriate locations

• Use of audible warning systems, wherever necessary

• RF leakages tests, (periodic/continuous) interlocked to machine operation, should be

incorporated if necessary

• References:

• ICNIRP Guidelines for limiting exposure to time-varying electric, magnetic and electromagnetic

fields (up to 300 GHz), Health Physics 74 (4):494‐522; 1998

• ICNIRP Guidelines, pp 498-508

• ICNIRP Guidelines, pp 512

• ICNIRP Guidelines, pp 513-514


AERB & IPR, 23-25 Nov 2016

• There are eight accelerator facilities in BARC , complies with the guidelines and recommendations of the Unit Level Safety Committee-Particle Accelerator (ULSC-PA), the Operating Plant Safety Committee (OPSRC) and the BARC Safety Council (BSC).

• ULSC-PA reviews all the facilities periodically.

• All the facilities are observing high level of safety standards.

Conclusion

Thanks


Dr Herb and Jim Ferry developed Pellet Charging system.


Professionals Meet


Typical module Quarter wave resonator

Date post:	17-Mar-2018
Category:	Documents
Upload:	builiem
View:	216 times
Download:	3 times

Safety aspects in Particle · PDF filenitrogen capture line at 10.86 MeV was identified in ......

Documents