1 / 26

MD report: IP aperture scans

MD report: IP aperture scans. P. Grenier, W. Kozanecki & M. Weaver + S. Ecklund's watchful eyes!. MD goals Experimental procedure HER-only x & y scans + high-current extrapolation [LER only X & y scans] + high-current extrapolation. MD goals.

allene
Download Presentation

MD report: IP aperture scans

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MD report: IP aperture scans P. Grenier, W. Kozanecki & M. Weaver + S. Ecklund's watchful eyes! • MD goals • Experimental procedure • HER-only x & y scans + high-current extrapolation • [LER only X & y scans] + high-current extrapolation

  2. MD goals • Quantify Babar background sensitivity to IP x & y angles for • single beams (HER & LER separately, moderate currents) • collisions (moderate currents, then high currents) and determine the optimum angles (from the background viewpoint) • Cross-calibrate • LIPP & HIPP BPMs • Babar luminous & boost angles against support-tube (ST) BPMs • Determine LER IP angles  center of luminosity monitor • absolute angles (from ST BPMs) at moderate current • reference angles (from HIPP & LIPP), corrected for high-current operation

  3. Support-tube (ST) BPMHIPP BPMLIPP BPM Locations of the IP BPMs & neutron monitors Neutron_forw_1 Neutron_forw_2 Neutron_bckw_1 CsI 7

  4. (Intended)Measurement Sequence • Setup • colliding beams, offset by-2 patterns at 300 mA ea. • Single-beam scans: Babar on • HER • XP scan, then YP scan @ 300 mA, offset pattern • with XP & YP at optimum, raise IH as high as it will go, to measure current-dependence of support-tube (ST) - L/HIPP correlation • LER • XP scan, then YP scan @ 300 mA, offset pattern • with XP & YP at optimum, raise IL until ST BPMs saturated • Luminosity-monitor scans: Babar on • YP(e+) scan attempted; failed bec. IP Multiknob fbk not functional • Current-dependence of ST-L/HIPP correlation in collision • most likely different from single-beam (heat from both beams) • Background scans @ high current: XP(e-), YP(e+), XP(e+), YP(e-) • beam-beam tails behave diffferently from beam-gas

  5. Experimental procedure • Operating procedure: general • manual scans, CRR plots vs time • monitor angles with ST BPMs, LIPP/HIPP orbit fits & monitoring fbks • monitor temps & vacuum throughout the scans • trickle, Babar on (incl. DAQ, with background-enriched trigger) • Initial setup: colliding beams, offset patterns, trickle, Babar on • bunch patterns • LER: by-2, 300 mA, buckets 400-3400. BPM measdef @ bucket 3200 • HER: by-2, 300 mA, buckets 0-3000. BPM measdef @ bucket 200 • set initial IP angles based in May 2005 lumi-monitor settings (exc. XP-) • LER XP = 9.25 mrad (ST BPMS) YP = - 1.1 mrad (ST BPMs) • HER XP = -16.7 mrad (ST BPMS) YP = + 1.1 mrad (ST BPMs)

  6. YP_ST (e-) during XP scan HER-only scans: current- & angle history HER current XP_ST (e-) YP_ST (e-)

  7. HER-only scans: ST vs HIPP BPMs @ 300 mA XP (HIPP) vs. XP_ST XP (orbFit) vs. XP_ST YP (orbFit) vs. XP_ST YP (HIPP) vs. XP_ST

  8. HER-only XP scan (1a) Normalized to HER-only prediction TR-23 (EMC) x 2.6 x 1.7 BW dmd, normalized E-collim (PR12 9082) x 2.3

  9. PR02 VP8020 HER-only XP scan (1b) PR02 VP7032 CsI 3054 PR02 VP8029

  10. HER-only XP scan (2a) SVT occpcy,  = 180 (W) SVT occpcy,  = 0 (E) x 2.7 x 3.6 neutron fwd_1 x 11

  11. PR02 VP8027 HER-only XP scan (2b) PR02 VP7042 PR02 VP7034 PR02 VGH_8027

  12. HER-only YP scan (1a) Xcoll PR12 7102 Ycoll PR12 8072 CSi7052 neutron bwd_1

  13. HER-only YP scan (1b) SVT occpcy,  = 0 (E) SVT occpcy,  = 180 (W)

  14. PR02 VP8027 HER-only YP scan (1c) PR02 VP8020 PR02 VGH_8027

  15. HER-only YP scan (2) TR-23 (EMC) BW dmd, normalized neutron fwd_1 Normalized to HER-only prediction

  16. HER-only YP scan (3) neutron fwd_2 CSi3054 PR02 VP8024

  17. High-current extrapolation: HER-only HER current XP_ST (e-) YP_ST (e-)

  18. HER-only YP scan (4) E-collim (PR12 9082) PR02 VP8029

  19. High-current extrapolation (HER-only): ST vs HIPP XP (HIPP) XP (HIPP) vs. XP_ST (e+) YP (HIPP) vs. YP_ST (e+)

  20. High-current extrapolation (HER-only) (1a) BW dmd, normalized Dynamic pressure E-collim (PR12 9082) TR-23 (EMC)

  21. High-current extrapolation (HER-only): pressure sampling Thermal outgassing

  22. High-current extrapolation (LER-only): angles vs. I LER current YP_ST (e+) XP_ST (e+)

  23. High-current extrapolation (LER-only): ST vs. LIPP XP (YIPP) YP (LIPP) YP_ST (e+) XP_ST (e+)

  24. To do… • Document usable scan ranges • first pass (PG) @ http://www.slac.stanford.edu/BFROOT/www/Detector/Backgrounds/ApertureScan-05Mar07.html • supply tables of XP(LER/HER, ST BPMS) vs. time stamps • Detailed analysis for each subdetector • SVT occupancies, DCH current + occupancies, DIRC scalers & currents - use normalized quantities (2004) wherever possible • clean up data sets (e.g. remove spikes associated with LER LFB problems, with knob turning, etc) • how well does the 'family' concept hold? • Analyse temperatures • Analyse vacuum signatures Volunteers needed!

  25. Summary (preliminary!) • Background sensitivity to single-beam aperture scans @ 300 mA • significant, may explain part of the discrepancy w/ Jan '04 norm'lztn; • is different, in both magnitude & optimum, for different subdetectors. The overall background optimum is incompatible with the SR load, at least in the HER (LER tba) • There may be subdetectors 'families' that depend on X/Y, HER/LER; within one scan, several sources are at work, depending on the direction of SR fans & local aperture restrictions. • Consistency between ST BPM's & LIPP/HIPP • much improved since run 5 • degrades as current increases, esp. for LER XP • Luminosity monitor scan • could not be completed for lack of working IPO Multiknob feedback. Can the fast dither play the same role? We need to know the center! • may yield LER IP angles different from the single-beam optimum. • No reason to believe that this single-beam optimum will coincide with that for beam-beam tails: need to explore XP & YP optimization on both L and backgrounds under physics conditions!

  26. Appendix: CRR plot files & data sets • PEP-II e-log: 5 March 2007 day + swing shift See also http://www.slac.stanford.edu/BFROOT/www/Detector/Backgrounds/ApertureScan-05Mar07.html for scan times & ranges • CRR button files • BBR_BKG_LERIPORB.btn • BBR_BKG_HERIPORB.btn • BBR_ALL_BKG.btn • All data in PHYSICS_DATA:[pep2.char.05mar07]

More Related