MICE Target

1. MICE Target CM 33 Glasgow 25th – 29th June 2012 P. J. Smith on behalf of the MICE target team.

2. Contents • 1) Target Operations on ISIS • Target Performance • BPS • 2) Target Operations in R78 • T1.1 / T1.2/T1.3 • New Controller Tables • Voltage Monitoring • 3) New Stator Development • 4) Future Plans P. J. Smith - MICE Target Team

3. Target Operations on ISIS Use so far.. Total count: 240,268 P. J. Smith - MICE Target Team

4. Target Operations on ISIS • Use Width of Starting Position as performance indicator, which tends to broaden over time. • The ISIS target reached a maximum of 1mm towards end of December run.. • Full width was reduced after December run, now at 0.6mm T2.9(ISIS) 0.6mm wide T2.8(R78) • Width is comparable to the previous test (T2.8). • If anything looking slightly better at the moment 0.9mm wide P. J. Smith - MICE Target Team

5. Target Operations on ISIS • Use initial acceleration as another diagnostic of performance, which tends to drop over time. • Also see a second lower band appear… • We would expect ISIS plot to be noisier because acceleration is dependent upon dip depth (R78 is constant.) T2.8(R78) P. J. Smith - MICE Target Team

6. Target Operations in R78 Target Operations in R78 Since CM 32 P. J. Smith - MICE Target Team

7. Target Operations in R78 • At CM32 we reported that we had just started running test T1.1 • T1.1 This was a test to 1 million pulses to compare stator T1 with stator. DLC shaft/Vespel bearings combination. • T1.2 Uncoated/Vespel. Ran for 2m actuations before we did a target inspection. • T1.3 Uncoated/Vespel on new bearings. This was run at higher voltage and compared with nominal voltage new/old controller tables for comparison. This target was partially inspected 12/06/2012 and is still running. • R78 has run pretty much continuously since the last CM. The only down time has been due to target changes/inspections, controller error conditions and a blown fuse on a power supply. P. J. Smith - MICE Target Team

8. T1.1 • Target Initially performed very well so continued test beyond 1m actuations. • Marked change at 2.7million actuations, followed by bimodal behaviour, so we decided to inspect at this point. • Step changes in Acceleration are due to changes in thermocouples and the necessary correction not being applied. No daily stops Change of thermocouple – but temperature correction not altered. (Different for each thermocouple) Bimodal Behaviour P. J. Smith - MICE Target Team

9. T1.1vs T2.8 This is a comparison of T1.1 with T2.8 It has always been felt that T1 is the better stator. No daily stops Change of thermocouple – but temperature correction not altered. (Different for each thermocouple) Bimodal Behaviour P. J. Smith - MICE Target Team

10. T1.1 Inspection Photos • There is more dust than previously observed but it should be borne in mind that this target had run to 3 million actuations before inspection. • No dust had migrated through the dust catcher. P. J. Smith - MICE Target Team

11. T1.2 • T1.2 Uncoated Titanium Shaft/Vespel • Ran well to 2.1 m actuations after what appeared to be a wearing in period. • Decided to inspect at 2m as this was an untried combination. • As you will see not much dust but there is a titanium element to the dust. • No migration through the dust catcher but with a metallic element in the dust our baseline will continue to be DLC/Vespel Initial Running in Period? P. J. Smith - MICE Target Team

12. T1.2 Inspection Photos 2 million actuations - Inspection photos montage! P. J. Smith - MICE Target Team

13. T1.3 • T1.3 Uncoated Shaft/Vespel combination. Reused shaft from T1.2 with new bearings. • Test was initially to try some extended running at slightly higher voltages. • During this period we updated the firmware to change the way in which the stator coils were switched. – Effectively increases the current for a given voltage thereby increasing acceleration. New ROM tables in controller. 115V 0.8 Hz 125V 0.7 Hz 115V 0.8 Hz

14. T1.3 Inspection Photos Partial Inspection at 2.7m actuations on 12/06/12 A full inspection was not done as we wished to continue running the target without disturbing the bearings. Minimal dust observed, no concern about any migration through the dust catcher. P. J. Smith - MICE Target Team

15. Voltage Monitoring • We initially wanted to observe the optical signals in R78 to see if there was any long term degradation in the received signals from the optical fibres that are used for determining the target’s position. This will then be used as a baseline to compare with the signals received from the target on ISIS. • The aim here is to see if we observe radiation damage to the long lengths of optical fibres used on the ISIS installation. • There are artefacts in the collected data that we couldn’t explain, and we were suspicious that these may be caused by voltage fluctuation on the mains. The ADC channels we are using were not originally intended for precision measurements and so were not referenced – a mistake that wont be repeated!! • We wanted to monitor the voltage in R78 to correlate this to the observed signal we see on the optics coming. P. J. Smith - MICE Target Team

16. Voltage Monitoring • Fibre brightness is top data set and voltage monitoring is bottom data set in each plot • There looks to be a correlation in the spikes, these look diurnal, but there are other trends that don’t quite match up • A more rigorous analysis is to be done on this data when Ed gets the opportunity. • This will provide a baseline for comparing with the fibre performance in ISIS. Channel A Brightness upper data Mains Voltage Lower data set Channel I Brightness upper data Mains Voltage Lower data set P. J. Smith - MICE Target Team

17. New Stator • At last CM we had a wound stator but it had failed electrical tests. However much was learnt in assembling this stator. • Since then: • Another stator was wound and this passed the electrical tests. (1kV DC breakdown test) Note operational voltage is ~115V • Several test pieces (including the first stator mentioned above) were used to test the potting process. Once this process had been perfected the good stator was potted. • This stator is now due to be transported to DL for field mapping and thermal testing. P. J. Smith - MICE Target Team

18. New Stator Assembled new stator (the good one) Cross section through a sample coil after a trial potting. Potted stator. P. J. Smith - MICE Target Team

19. Future Plans • With the exception of the work to be done on new stator, the existing target system is now largely in maintenance mode. • Periodic firmware/software updates as necessary. • Testing new combinations of shaft/bearings/control in R78. • The new Stator will be taken to DL for field mapping/thermal testing and then taken to R78 for an extended running period. • A spare PSU is currently being built as the current units that are in service are using some obsolete components. This new PSU will provide a hot spare for use at RAL. • Beam Protection System (BPS) to be fully commissioned. • Awaiting new ‘Halbach’ array magnets for trialling. These should give a significant performance improvement. P. J. Smith - MICE Target Team

20. Conclusions • The Target on ISIS has performed to expectation. • The R78 test rig has run almost continuously since the last CM; targets have proven to be reliable and performed to expectation. • Currently running Titanium/Vespel until wear is evident in DAQ or we need the R78 rig to test the new Stator. • The first New stator to have passed electrical testing has been potted and will soon be going to Daresbury Labs to be field mapped/power tested. • First tests of this new stator in R78 is expected to commence later in July. • We will soon have a hot swap spare PSU (Hex Bridge) at RAL. P. J. Smith - MICE Target Team