1. Nuruzzaman (https://userweb.jlab.org/~nur/)https://userweb.jlab.org/~nur/ Beam Modulation System for the Q-weak Experiment at Jefferson Lab

2. Q-weak basics and motivation for beam modulation system. Experimental setup and design. Data taking and analysis. Preliminary results. Summary 2 Overview Nuruzzaman CIPANP 2012

3. Q-weak Basics and Motivation The objective of the Q p weak experiment is to measure the parity violating asymmetry (~250ppb) in elastic electron-proton(e-p) scattering to determine the proton's weak charge with an uncertainty of 4%.[1] [1] http://www.jlab.org/qweak/ A PV = σ + - σ - _______ σ + + σ - The e-p scattering rate depends on the five beam parameters: horizontal position (X), horizontal angle (X΄), vertical position (Y), vertical angle (Y΄) and energy (E). A measured = A 0 + ∂A ∂T i ∆T i ∑ i T i = X, X´, Y, Y´ & E ∂T i ∂A = detector sensitivity The goal of the Q p weak group is to keep these helicity-correlated parameters as small as possible and measure detector sensitivity to correct false asymmetry. We use a pair of dipoles to move the beam with controlled sinusoidal drive signal and carefully setup beamline optics along the transport line to the target and measure detector sensitivities for different beam parameters. 3 Nuruzzaman CIPANP 2012 Basics Setup & Design Analysis Result Summary

4. Experimental Setup Beam Position Monitor Modulation Coil Pair Hall-C Injector Accelerator 1 st Pair of Coils 2 nd Pair of Coils BPM QTOR Cherenkov Detector Luminosity Monitors A B C 4 Nuruzzaman CIPANP 2012 Basics Setup & Design Analysis Result Summary

5. Basic Idea of Modulation using a Pair of Small Dipole Magnets Hall C Beamline Zoomed In Target z x / y θ1θ1 θ2θ2 θ1θ1 II I I Z=0 Z=d 1 Z=d 2 where Incoming beam Dipole 3C05 Dipole 3C06 Diploe 3C07 Quad. 3C11 Quad. 3C11 5 Nuruzzaman CIPANP 2012 Basics Setup & Design Analysis Result Summary

6. Data taking conditions: Run non-invasively during production running. A typical run is ~ 1hour of data. Target: LH 2, Al. Beam current: 10 -180 µA. Modulation with pair of coils and single coil. Modulation frequency: 67, 125 Hz. Modulation tunes (I 2 /I 1 ) : I, IIA, IIB, III, IV … This presentation includes: Time span: 14 th February 2011 – 18 th May 2012 6 General Information of BMod Data Taking Nuruzzaman CIPANP 2012 Basics Setup & Design Analysis Result Summary

7. Modulation Cycle X X´ Y Y´ E 7 Nuruzzaman CIPANP 2012 320 s 4 s Basics Setup & Design Analysis Result Summary

8. Phase FGX1 [V] FGX2 [V] BPMX [mm] BPMY [mm] Target BPM Response to X Position Modulation BMod drive signal for horizontal pair of magnets Target BPM response to X modulation 8 Nuruzzaman CIPANP 2012 Basics Setup & Design Analysis Result Summary

9. Hall-C BPM Response to X Position Modulation 9 Nuruzzaman CIPANP 2012 Basics Setup & Design Analysis Result Summary

10. 12000: Hall-C BPM X Response to X- Modulation Phase-I: 7 th May 2011 10 Nuruzzaman CIPANP 2012 Basics Setup & Design Analysis Result Summary

11. 15722: Hall-C BPM X Response to X- Modulation BPM-X response has not changed much in Run-II compared to Run-I 11 Nuruzzaman CIPANP 2012 Phase-II: 3 rd February 2012 Basics Setup & Design Analysis Result Summary

12. Preliminary Tune-I Tune-IIA Tune-IIB Vacuum Leak Phase-I: Target & BPM 3C12 Response to X- Modulation X responses are reasonably stable X-Y coupling at target ! Need to figure out the outlier ?? Moller Runs BMod Tune-I 18 – 19 February 2011 Moller Quad cycling seems to change the optics occasionally !! Moller Runs BMod Tune-IIB 7 – 9 May 2011 Reasonably stable optics during end of RUN-I 12 Nuruzzaman CIPANP 2012 Basics Setup & Design Analysis Result Summary

13. Phase-II: Target & BPM 3C12 Response to X- Modulation Preliminary X response is reasonably stable X-Y coupling at target. Tracking down the outliers. 13 Nuruzzaman CIPANP 2012 Basics Setup & Design Analysis Result Summary

14. X Sensitivity from BMod and Natural Beam Motion 14 Nuruzzaman CIPANP 2012 Preliminary Basics Setup & Design Analysis Result Summary

15. Coil positioning and tunes were achieved using OPTIM simulation and hardware installed and commissioned in 2009. Hardware and software worked fine during Q-weak data taking for last ~ 2 years. Finished data taking. Preliminary observation: o Optics is more stable during Run-II compared to Run-I. o X-Y coupling not understood. o Occasionally Moller runs seem to change the optics. o Sensitivities are reasonable. Investigating Hall-C optics and extracting detector sensitivities using beam modulation and natural beam motion. 15 Nuruzzaman CIPANP 2012Summary Basics Setup & Design Analysis Result Summary

16. The Q-weak Collaboration (http://www.jlab.org/qweak/collaboration.html)http://www.jlab.org/qweak/collaboration.html A. Almasalha, D. Androic, D.S. Armstrong, A. Asaturyan, T. Averett, J. Balewski, R. Beminiwattha, J. Benesch, F. Benmokhtar, J. Birchall, R.D. Carlini 1 (Principal Investigator), G. Cates, J.C. Cornejo, S. Covrig, M. Dalton, C. A. Davis, W. Deconinck, J. Diefenbach, K. Dow, J. Dowd, J. Dunne, D. Dutta, R. Ent, J. Erler, W. Falk, J.M. Finn 1 *, T.A. Forest, M. Furic, D. Gaskell, M. Gericke, J. Grames, K. Grimm, D. Higinbotham, M. Holtrop, J.R. Hoskins, E. Ihloff, K. Johnston, D. Jones, M. Jones, R. Jones, K. Joo, E. Kargiantoulakis, J. Kelsey, C. Keppel, M. Kohl, P. King, E. Korkmaz, S. Kowalski1, J. Leacock, J.P. Leckey, A. Lee, J.H. Lee, L. Lee, N. Luwani, S. MacEwan, D. Mack, J. Magee, R. Mahurin, J. Mammei, J. Martin, M. McHugh, D. Meekins, J. Mei, R. Michaels, A. Micherdzinska, A. Mkrtchyan, H. Mkrtchyan, N. Morgan, K.E. Myers, A. Narayan, Nuruzzaman, A.K. Opper, S.A. Page 1, J. Pan, K. Paschke, S.K. Phillips, M. Pitt, B.M. Poelker, J.F. Rajotte, W.D. Ramsay, M. Ramsey-Musolf, J. Roche, B. Sawatzky, T. Seva, R. Silwal, N. Simicevic, G. Smith 2, T. Smith, P. Solvignon, P. Souder, D. Spayde, A. Subedi, R. Subedi, R. Suleiman, E. Tsentalovich, V. Tvaskis, W.T.H. van Oers, B. Waidyawansa, P. Wang, S. Wells, S.A. Wood, S. Yang, R.D. Young, S. Zhamkochyan, D. Zou 1 Spokespersons *deceased 2 Project Manager

17. Backup Slides 17 Nuruzzaman

18. BPM sign correction 18 Nuruzzaman

19. BPM 3C19Y was ZERO for whole Run-I period Problem 1: ? BPM 3C19X was ZERO for whole Run-I period Problem 1: ? BPM 3C16Y was INVERTED for whole Run-I period Problem 2: ? 7 th May 2011 Figure 1 and 2 is for run 12000 from 7 th May 2011. This is a typical production run from Run-I and also represent it. Here in Figure 1 we observed BPM 3C19X has zero response to X-modulation. In Figure 2 we observed BPM 3C19Y has zero and 3C16Y has inverted response to Y-modulation. Figure 1: Hall-C BPM X responses to X - Modulation Figure 2: Hall-C BPM Y responses to Y - Modulation 19 Nuruzzaman

20. BPM 3C19Y was non-ZERO after some changes in the cable on 2 nd January 2012 (ELOG 1656869)ELOG 1656869 Problem 1: Fixed BPM 3C19X was non-ZERO after some changes in the cable on 2 nd January 2012 (ELOG 1656869)ELOG 1656869 Problem 1: Fixed 31 st January 2012 Figure 3 and 4 is for run 15646 from 31 st January 2012. This is a production run. In Figure 3 we observed a non zero BPM 3C19X response to X-modulation. In Figure 4 we observed BPM 3C19Y has non zero and 3C16Y has inverted response to Y-modulation. Figure 3: Hall-C BPM X responses to X - Modulation Figure 4: Hall-C BPM Y responses to Y - Modulation 20 Nuruzzaman

21. BPM 3C16Y was back to NORMAL after some cable switching on 1 st February 2012 (ELOG 1663052)ELOG 1663052 Problem 2: Fixed 2 nd February 2012 Figure 5 and 6 is for run 15646 from 2 nd February 2012. This is a production run. In Figure 5 we observed a non zero BPM 3C19X response to X-modulation. In Figure 6 we observed BPM 3C19Y has non zero and 3C16Y has normal response to Y-modulation. Figure 5: Hall-C BPM X responses to X - Modulation Figure 6: Hall-C BPM Y responses to Y - Modulation 21 Nuruzzaman

22. General Information of BMod Analysis Run conditions: Production run. Target: LH 2, Al. Beam current: 10 -180 µA. Modulation with pair of coils and single coil. Modulation frequency: 67, 125 Hz. Modulation cycle: 510 cycles. 4 s/cycle. 320 s/macro cycle. Three modulation tunes (I 2 /I 1 ) : I, IIA, IIB, III, IV Cuts and conditions: ramp>0 (baseline noise) (ramp.Device_Error_Code&0x80)==0x80 (device saturation) abs((ramp.block0+ramp.block3)-(ramp.block1+ramp.block2))<50 (edge effect of triangular wave) qwk_bcm1.Device_Error_Code==0 or qwk_bcm8.Device_Error_Code==0 (beam trip) ErrorFlag == 0x4018080 (stability) bm_pattern_number == (coil pair: 10 for X, 11 for Y, 12 for E, 13 for X’ & 14 for Y’ single coil: 0 for X 1, 1 for Y 1, 2 for E, 3 for X 2 & 4 for Y 2 ) This presentation includes: Time span: 14 th February 2010 – 18 th May 2012 All the runs with modulation data Mps_Tree 22 Nuruzzaman

23. Detailed Analysis 23 Nuruzzaman

24. Moller Runs BMod started here [1] https://hallcweb.jlab.org/hclog/1102_archive/110214194923.htmlhttps://hallcweb.jlab.org/hclog/1102_archive/110214194923.html [2] https://hallcweb.jlab.org/hclog/1102_archive/110215001509.htmlhttps://hallcweb.jlab.org/hclog/1102_archive/110215001509.html 24 Nuruzzaman

25. Hall-C Network problem/ Hall-B going to Pass5 ?? Moller Runs MCC is setting ion chambers for Hall-A 25 Nuruzzaman

26. Very short run, Large charge asym during 10161 26 Nuruzzaman

27. Large charge feedback, transition run Vacuum Leak Moller Runs 27 Nuruzzaman

28. Vacuum Leak Moller Runs Ramp was not functioning properly, software problem, will fix latter. https://hallcweb.jlab.org/hclog/1103_archive/110331060326.html 28 Nuruzzaman

29. Ramp was not functioning properly, software problem, will fix latter. Moller Runs BMod tune change 29 Nuruzzaman

30. Very short, transition run Bad fit 30 Nuruzzaman

31. Bad fit Moller Runs 31 Nuruzzaman

32. Beam trip, may be cut problem/ TS communication problem?? Moller Runs 32 Nuruzzaman

33. MCC autosteer/ BCM 2 test Moller Runs 33 Nuruzzaman

34. Moller Runs 34 Nuruzzaman

35. Bad quality beam ? Moller Runs 35 Nuruzzaman

36. Moller Runs 36 Nuruzzaman

37. Moller Runs 37 Nuruzzaman

38. 38 Nuruzzaman

39. Bad run, QTOR trip, no beam most of the time ? Moller Runs 39 Nuruzzaman

40. FFB was OFF Moller Runs 40 Nuruzzaman

41. Moller Runs Weird 3C12X & Y response. Marked run as suspected. 41 Nuruzzaman

42. 42 Nuruzzaman

43. Short run, Target boiling test Moller Runs 43 Nuruzzaman

44. Transition run Moller Runs Moller Runs BMod tune change 44 Nuruzzaman

45. Moller Runs 45 Nuruzzaman

46. Energy measurement run Moller Runs 46 Nuruzzaman

47. Experimental Setup 47 35 cm Liquid Hydrogen Target Primary Collimator with 8 openings Drift Chambers Toroidal Magnet Drift Chambers Elastically Scattered Electron Eight Fused Silica (quartz) Čerenkov Detectors - Integrating Mode Luminosity Monitors ~3.2 m Basics Experimental Setup Hardware Analysis Result Summary

48. Hardware Sketch Beamline Coils X1X1 Y1Y1 Y2Y2 X2X2 SRF E BSY Service Building BMOD1BMOD1 X1X1 X1X1 Y1Y1 Y1Y1 X2X2 X2X2 Y2Y2 Y2Y2 LEM Current Transducer X1X1 Y1Y1 Y2Y2 X2X2 TRIM-I Power Amp. BPMs BMOD2BMOD2 Hall-C GUI CONSOLE Q p weak PV Daq. Q p weak Cage I O C hCnmrhCnmr TRIUMF ADC JLAB ADC

49. 12000: Hall-C BPM Y Response to Y- Modulation 7 th May 2011Run-I 49 Nuruzzaman

50. 15722: Hall-C BPM Y Response to Y- Modulation 3 rd February 2012Run-II BPM-Y response has slightly improved in Run-II 50 Nuruzzaman

51. 12000: Hall-C BPM X Response to E- Modulation 51 Nuruzzaman CIPANP 2012 Run-I: 7 th May 2011

52. 15722: Hall-C BPM X Response to E- Modulation Residual dispersion at the target shows slight improvement during Run-II 52 Nuruzzaman CIPANP 2012 Run-II: 3 rd February 2012

53. 12000: Hall-C BPM Y Response to E- Modulation 53 Nuruzzaman CIPANP 2012 Run-I: 7 th May 2011

54. 15722: Hall-C BPM Y Response to E- Modulation Residual dispersion in Y target also shows improvement 54 Nuruzzaman CIPANP 2012 Run-II: 3 rd February 2012

55. Tune-I Tune-IIA Tune-IIB Vacuum Leak Run-I: Target & BPM 3C12 Response to Y- Modulation Y response is less stable (partly by design) No X-Y coupling. 55 Nuruzzaman

56. Run-II: Target & BPM 3C12 Response to Y- Modulation Y response is less stable No X-Y coupling. Need to track down outliers 56 Nuruzzaman

57. Preliminary Tune-I Tune-IIA Tune-IIB Vacuum Leak Run-I: Target & BPM 3C12 Response to E- Modulation X 3C12 response is drifting slightly with time. Residual dispersion coming from upstream in X and Y. Y tgt (≥X tgt ) has ~ 1/7 th dispersion of 3C12X! 57 Nuruzzaman CIPANP 2012

58. Preliminary Run-II: Target & BPM 3C12 Response to E- Modulation 3C12-X response to energy modulation is reasonably stable until recently Residual dispersions sometimes zero in X, still often bad in Y Tracking down outliers 58 Nuruzzaman CIPANP 2012