MICE Installation and Commissioning meeting

RAL, 12 June 2007

Diffuser

Oxford University

A re-cap on where we were, and the space constraint of placing the diffuser into the tracker solenoid bore

145mm is all we can have !!

Beam direction

Clearance envelop for the diffuser assembly approx. 145 mm

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Tracker solenoid Iro

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ldClearance gap = 250mm

Pat

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Tracker solenoid

Iro

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ldClearance gap = 250mm

The space constraint & positioning requirement

for the diffuser

105 mm

163 mm from flange face

Diff

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ition

Carousel sub-assembly – for selecting the right diffuser plate

The driving system – air motors (3-off)

Control & locking device

Diffuser plate transport system

Travels some 300mm

Patch panel

A reminder of how the mechanism works

The central carousel is gear driven, and allows the selected disk to be placed outside the tracker solenoid bore, waiting to be taken in

The inching mechanism allows the disk to be off- loaded from the central carousel and be loaded onto the disk carrier. This motion is driven by a dedicated air motor.

Loading and off-loading of the diffuser plates is provided by two sets of bayonets; one at the carousel and the other on the disk carrie.

Since the last CM meeting (CERN Feb 2007), a number of changes were made:-

1) Diameter of the lead disk. They are:-

Make up disk 10 thk, ID 254, OD 300

Main disk Ø254, variable thickness

Since the last CM meeting (CERN Feb 2007), a number of changes were made:-

1) Size of the lead disk. They are:-

2) Thickness of the disk. Each of the 5 disks has its own different thickness. They are:-

15.5mm10 mm7.5 mm 5 mm1.5 mm

Since the last CM meeting (CERN Feb 2007), a number of changes were made:-

1) Size of the lead disk. They are:-

2) Thickness of the disk. Each of the 5 disks has its own different thickness. They are:-

15.5mm10 mm7.5 mm 5 mm1.5 mm

We are studying if the 1.5mm thick lead disk is structurally stable

Since the last CM meeting (CERN Feb 2007), a number of changes were made:-

1) Size of the lead disk. They are:-

2) Thickness of the disk. Each of the 5 disks has its own different thickness. They are:-

15.5mm10 mm7.5 mm 5 mm1.5 mm

3) Planetary gears, control logic and locking mechanism have been introduced to the design to enable fine adjustment on the selection and positioning of the diffuser moving parts;

In existing design, the material for all the gears are Aluminium.

In new design, the material for the gear teeth are changed to Stainless Steel. The SS is added carrying the gear teeth, keyed and bolted to the Al disk holders.

The advantage of the change:

1. Stainless steel for the gear teeth is more wearable.

2. Gear teeth can be replaced without having to replace the whole carousel.

The disadvantage:

Mass increased 1kg per gear.

Material changes

Progress & Schedule:-

Detail design on the control and locking mechanism is still on-going;

We are releasing some part of the diffuser for manufacturing so that we can maintain our original schedule for installing the prototype into the decoy tracker module at IC;

Until we have the prototype mounted properly, it would be difficult to adjust the control and locking mechanism to achieve its required precision;

We schedule to have the prototype ready by the beginning of September;