TARGET WORKSHOP – SHEFFIELD HALLAM UNIVERSITY

Monday 2 March 2009

The ISIS – MICE interface

Eddie McCarron

Contents1.Target alignment with ISIS beam centre line.

2.Target redesign and QA.3.MICE M113 vessel mods.

4.MICE target removal/installation mods.5.Actions and aims

1

Transferring beam datum from ISIS to MICE target

The beam centre cannot be measured directly. The synchrotron parts are aligned with Taylor-Hobson (TH) datum balls from a fixed gridsystem in the synchrotron hall. Each part has two TH reference points that are pre aligned with a pair of rails.

Taylor-Hobson cup.For dipole.

Fixed grid reference tower.

The TH points for the MICE vessel are mounted on removable jigs that sit on the flange dowels at either end of the vessel.

2

Target tip is not directly referencedto the synchrotron TH system.

The target tip must be referenced to the trial assembly rig in R78 then transferred to the synchrotron to obtain relationship between target tip and beam centre line.

3

Procedure for calibrating the target tip to beam centre line.

1. The telescope is set up to view at a known offset parallel to the beam centre line.

2. The target is driven to a known positionby the solenoid.

3. The telescope is moved to view the tip of Target.

4. The mechanical off set is recorded andlogged with the reading from the solenoiddrive software.

5. The target tip is now calibrated to the vessel dowels. This setting is now transferable to the synchrotron.

4

Target shaft redesign

It is clear that the vulnerable parts of the target assembly are the target shaft and the driving coils and both their problems are dominated by F = ma. For the coils to produce ‘F’ they need ‘I^2’. I presume we have minimised ‘a’ and are taking steps to minimise ‘m’.

Minimising the gap between the target shaft magnets and the coils would reduce the magnetic field necessary to generate ‘F’ (therefore reducing ‘I^2’). I don’t think this has been addressed.

It is also clear that there is a vibration problem. The vibrations are proportional to the acceleration, second moment of area,length and the Young’s modulus of the target shaft. I believe each of these has been addressed.

Target assembly Quality Assurance (QA)

Following the note* about QA issued 22 May 2006. There have been some steps towards fully controlling the Target assembly production to QA methods so that reliable and repeatable assemblies can be installed. It is now time to audit these procedures. To ensure that all our stages are specification driven, inspected, and documented I suggest that an independent QA auditor is consulted. Perhaps SSTD at RAL have someone we can borrow for a day or two.

* ‘MICE Target Mechanical Acceptance criteria’ 22 May 2006 attached for reference. 5

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Mods to MICE vessel M113 in synchrotron

The melting of the target tip endangered the observation window below the target. The window will be moved.A thermocouple will be added to a new VAT isolation valve so the target tip temperature can be monitored.

Thermocouple enters here

New ISIS pumpingport and valve.

Beam direction Moved observation windowLighting window

8

TC through Swagelok

Mirror

Pyrex ceiling

Thermal radiation collector onend of TC

Swagelok welded into valve by VAT

Details of M113 vessel of mods

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Removal/Installation mods ISIS remove excess grease

ISIS instal shim toprotect optics fromoil.

Sheffield to pass all cables throughthese holes to aid cable safety.

All cables to be have pucker labels.

Avoid routingcables aroundthese edges.(Or they will be trapped In transport casket).

Target assembly partly dismantled in R5.2 after removal from Synchrotron.

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Actions and aims

1.EM to progress vessel mods for delivery by May 2009.

2.Sheffield to provide in-line or quick release connectors to parts on Target assembly to ensure efficient Target installation in synchrotron.

3.Sheffield to route cables through target assembly plate to avoid crushing cables in lead casket transport.

4. Sheffield to use pucker cable labels.

5. Plan acceptance trials for R78.

6. Appoint a QA auditor (internal or external).

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