1. Jason Tarrant / November 2008 MICE Target Mechanical Design l Jason Tarrant – STFC l Introduction »Investigations into target shaft failure »Current suspicions and solutions »Shaft re-design »QA »Milestone plan

2. Jason Tarrant / November 2008 MICE Target Mechanical Design l Investigate Reason for Seizure of Shaft »High speed camera (see http://www.hep.shef.ac.uk/research/mice/target_videos/ )http://www.hep.shef.ac.uk/research/mice/target_videos/ »Vibration analysis (accelerometers) »Magnetic field measurement & analysis »DLC-DLC coating suitability –Friction / heat generated at bearing interface –Quality of DLC coating »+Differences between R78 & Sheff. Targets –Mounting –Dimensions –Surface finish

3. MICE Target Mechanical Design l Present thinking with indication of vibration = possible hammering between shaft and bearings l No solutions viable before January, but by April… »Improved DLC-DLC or alternative e.g. –Nitride type coating by HIPIMS process… –WS2… »Alternative shaft & bearing design to eliminate vibration l All of course dependant on investigation findings Jason Tarrant / November 2008

4. MICE Target Mechanical Design l Alternative Shaft & bearing »Current cruciform shape –Bearing more a guide due to clearances potential to rattle or hammer –‘+’ or ‘x’ same stiffness but for 11mm 2 CSA I = ~18mm 4, for a round shaft same CSA @ 6mm OD I = 39mm 4 > 2 x as stiff. Jason Tarrant / November 2008

5. MICE Target Mechanical Design l Alternative Shaft & bearing… »Round shaft –Needs anti-rotation device l Sprung follower on flat l Key in slot (slot on shaft) –Target attachment l Round tubular end as target l Formed flat target from tubular end l Threaded, pinned & welded Jason Tarrant / November 2008

6. MICE Target Mechanical Design l Alternative Shaft & bearing… »Bearing alignment –Clearance to be reduced as far as practical but dependant on: l Manufacturing tolerances on shaft and bearing (min and max clearance) l Bearing alignment (position and orientation) l Straightness of shaft Jason Tarrant / November 2008

7. MICE Target Mechanical Design l QA »Define all characteristics that could influence the running of the shaft in the bearings, e.g. –Coating thickness / hardness –Actual dimensions and shape of components »Control, Measure and record these important for… l Install in ISIS »Use R78 assembly? (determine wear / predict life) or refurbish »Use different assembly with close to identical characteristics Jason Tarrant / November 2008

8. MICE Target Mechanical Design l Schedule »Milestones –Coating investigations – Jan 09 –Shaft / bearing redesign review and approval – Dec 08 –First test pieces of new design – Feb 09 –Testing Sheffield / R78 complete – March 09 –Refurb / build & install in ISIS complete – April 09 –2 nd Target start cycling – April/May 09 Jason Tarrant / November 2008