1. MICE Target Report Chris Booth (for target team) Sheffield 24 th March 2010

2. Chris BoothUniversity of Sheffield 2 History & Overview T1 – DLC bearings – running in ISIS –>155k + 50 k actuations T2 – nominally identical to T1 –Bearing failed rapidly T2.2 – like T1, improved QA –Failed after ~80k actuations T2.3 – same stator & shaft as T2.2 –New Vespel (polyimide) bearings –Tested for >2.1M pulses in R78 Results of T1 running, T2.3 tests, and plans

3. 3 University of Sheffield BCD (beam centre distance) Histograms (analysis by Paul Hodgson) T2 distribution 3-4 times as broad Can be interpreted as a result of the target “sticking” Use the BCD histograms as a diagnostic to spot changes in target performance T1 T2 Chris Booth

4. T1 Calibration Plots Running in ISIS allowed subject to “target integrity tests” every 10k (formerly 5k) actuations 400 pulses taken under standard conditions Check for changes in behaviour Inspections for dust every 50k actuations 0.4 mm

5. Overlay of Calibration Plots

6. Chris BoothUniversity of Sheffield 6 Conclusions for Target 1 Target continues to perform reliably No sign of significant change in BCD distributions No sign of dust production on view port Keep running!

7. Status of Target 2 T2 Vespel installed in R78 Jan 25 th 2010 DLC coated shaft (from T2.2) – Vespel bearings Same stator body as previous T2 Pulsed target continuously for 2.15×10 6 pulses Approx. one month of operation at ~1 Hz Two short interruptions, chiller failed 1/2/2010, UPS failed 8/2/2010(!) Neither problem associated with target mechanical performance Target was deliberately stopped for inspection Very little dust on view-port (~ daily photos) Chris BoothUniversity of Sheffield 7

8. EarlyMidLate 720k s1680k s Change over ~1 day T2 BCD over month Start up period DAQ gain changes 1×10 6 pulses

9. University of Sheffield Look at BCD histograms in 3 regions Region 1 Early operation 120k – 360k pulses RMS 0.135 Asymmetric tail Region 2 Mid operation 720k – 960k pulses RMS 0.122 Asymmetric tail Region 3 late operation 1860k – 2100k pulses RMS 0.155 More symmetric with double peak structure but broader Chris Booth 9

10. Comparison of BCD plots for T1 (DLC) and T2 Vespel RMS of T2 Vespel is approximately twice that of T1 (Note different scales) T2 Region 3 T1 Chris BoothUniversity of Sheffield 10

11. T2 Acceleration over month Chiller failure Test power off UPS failure Chris BoothUniversity of Sheffield 11

12. T2 Acceleration regions Steady decline 848 to 838 ms -2 Stable operation (838 ± 5) ms -2 Increased variability Early Mid Late 720k s 1680k s Chris BoothUniversity of Sheffield 12

13. Questions and Comments How would the target have performed if we had carried on pulsing ? Remember we arbitrarily stopped at 2.15 × 10 6 pulses. Does the early period correspond to the target “bedding in” ? The mid period lasted approx. 1 million pulses where the target seemed to wear gradually. There was a reasonably rapid (1 day) change in performance after which the target parameters were (slightly) more variable. None of the variation seen above would compromise the normal target operation. The typical beam centre varies more than the target BCD. Chris BoothUniversity of Sheffield 13

14. Disassembly & Inspection of Target 2 (Jason Tarrant) Target stopped after 2.16M actuations Optics block removed & upper bearing exposed Bellows removed & lower bearing exposed Significant amounts of vespel dust, adhered to surfaces Chris BoothUniversity of Sheffield 14

15. Disassembly – View of upper Bearing MICE Target First look Little dust (polished flat) Most dust (rough flat) Polished flat Rough flat Amalgamated dust balls Dust On shaft, On bearing, On lock ring Survey point

16. University of Sheffield Disassembly – View of lower Bearing MICE Target Dust around bearing, lock ring removed Internal face External face Chris Booth 16

17. MICE Target Observation – Dust –Amount Most at upper bearing – esp. anti-rotate rough flat side (Only one flat on shaft polished) Amalgamated at bearings – scraped off –Location Coated internal components, has escaped externally How does it move / defy gravity? –Thrown off? –Electrostatic attraction? –Vibration movement? –When let up to air? –Attachment Fixed – by what? Chris BoothUniversity of Sheffield 17

18. University of Sheffield Next Steps? Reduce wear & dust production –Polished flats, burnished bearing faces –Possibly harder plastic (Duratron or Celazole) –Improved stator? (See below) Observe when dust produced Trap dust in catcher Further tests start in May Chris Booth 18

19. Stator QA Is stator 2 different from stator 1? –Map field, with assistance of group at Diamond –Support rig built by Geoff Barber –Chiller, PSU, temperature interlocks ready –Measurements to start this week –Stator 3 (unwelded) built in Sheffield –Permanent magnets will be (re-)measured –Modelling (Paul Smith, Owen Taylor?) to connect field asymmetries with off-axis forces Chris BoothUniversity of Sheffield 19

20. Target Electronics & DAQ Upgrade Phase 1 hardware complete, tested (Paul Smith) USB interface to PC –Menu-driven interface in use (see screen shots) –GUI under development (James Leaver) Control, monitoring, error notification Much simpler interface (for non-experts!) Plan to exercise thoroughly in R78 before installation in ISIS –Soak-test during next bearing evaluation Chris BoothUniversity of Sheffield 20

21. Menu-driven controls 12-Mar-10P J Smith - University of Sheffield Framework for terminal code programmed by James Leaver 21

22. Prototype GUI for Target Control 12-Mar-10P J Smith - University of Sheffield GUI screenshot provided by James. The exact layout may change a bit over the next weeks 22

23. Chris BoothUniversity of Sheffield 23 Summary Target 1 installed and operating well in ISIS Target 2 with plastic bearings performed reliably for >2M actuations –Stopped for inspection, not due to failure Test & measurement programme for reducing and trapping dust Stators will be mapped to improve QA FPGA-based control essentially ready – will give easier operation and enhanced monitoring