Shower Max Detector Plans for MOLLER

Transcription

1 Shower Max Detector Plans for MOLLER Dustin McNulty Idaho State University May 8, 14

2 MOLLER Shower Max Detector Outline Conceptual Design and Motivation Review 8 prototype stack Design Monte Carlo Beam tests and results Plans Dustin McNulty Shower Max Detector Plans for MOLLER 1

3 Detector Ring Design Concept Dustin McNulty Shower Max Detector Plans for MOLLER

4 Motivation Provides additional measurement of e-e ring flux Weights flux by energy less sensitive to low energy bkgds Dustin McNulty Shower Max Detector Plans for MOLLER

5 8 Shower Max Slide from Piotr Dustin McNulty Shower Max Detector Plans for MOLLER 4

6 8 Shower Max Detector Schematic stack Al mirror PVC Schematic from Piotr Dustin McNulty Shower Max Detector Plans for MOLLER 5

7 8 Shower Max Detector Frame from Piotr Dustin McNulty Shower Max Detector Plans for MOLLER 6

8 Piotr s MC: Tungsten and Quartz thickness study (for 9MeV electrons) Dustin McNulty Shower Max Detector Plans for MOLLER 7

9 Piotr s Simulations (Stray Electrons) Dustin McNulty Shower Max Detector Plans for MOLLER 8

10 Jan8 Testbeam Setup and Conditions Thin and Stack dets rigidly mounted along 45 angle; installed above rhrs focal plane (between VDC s and S1 scint. plane) E beam = 956 MeV, 5-5µA, 1mg/cm Ta target rhrs at 19, using VDC s and s trigger (removable) Counting rates 1 Hz/µA Dustin McNulty Shower Max Detector Plans for MOLLER 9

11 Jan8 Testbeam Setup Alignment y VDC1 z x Spectrometer Coord. System (side view) NOT TO SCALE TOP of VDC BOX VDCs upper chamber lower chamber s VDC PREx Detector Jan8 Beamtest Schematic Layout θο thin det = 55 1mm o stack det Q defocused (1% field increase) for further improvement y ~55mm z 4mm 45mm ~mm ~15mm 45 o x ~5mm 45mm Pb bricks PMT P P =+1.1% PREx Detector Central Ray 4mm PMT 56mm Nominal Central Ray ~15mm ~445mm Small detector footprint made FP alignment non-trivial Further complicated by space constraints from s1 scint. plane; creating the need for a P/P shift of +1.1% from nominal This shifted central ray from 45 to 55 Dustin McNulty Shower Max Detector Plans for MOLLER 1 v1 u1

12 Jan8 Testbeam Setup Alignment x Nominal Central Ray ϕ =. PREx Detector Central Ray ϕ =.5 o y Spectrometer Coord. System (top view) z NOT TO SCALE stack det PMT ~9mm thin det 4mm x 45mm s y z TOP of VDC BOX Dustin McNulty Shower Max Detector Plans for MOLLER 11

13 Jan8 Testbeam Run conditions Sumary Beam rhrs I beam Q Thin ADC Run E (GeV) angle Targ ( µa) Tweak s Det Change 51 a Pb 6 Before IN 1mm Before 661 b C 5 Before IN 1mm Before Ta 5 Before IN 1mm Before Ta 5 After IN 1mm After Ta 5 After IN 1mm Before Ta 8 After OUT 1mm After Ta 8 After OUT 5mm After Ta 5 After OUT 5mm After a This run occurred during the Lead target stress-tests at -pass. b This run occurred before rhrs P/P change to = +1.1 % (969 MeV). Dustin McNulty Shower Max Detector Plans for MOLLER 1

14 Jan8 Testbeam θ and φ Spectra Entries SCS Tracking θ (run686) ----cut on s ----cut on stk ----cut on thn θ (deg) Entries SCS Tracking φ (run686) ----cut on s ----cut on stk ----cut on thn φ (deg) Dustin McNulty Shower Max Detector Plans for MOLLER 1

15 Jan8 Testbeam x and y Spectra Entries/mm cut on s cut on stk ----cut on thn SCS Tracking x (686) SCS Tracking x (m) Entries/mm SCS Tracking y (686) ----cut on s ----cut on stk ----cut on thn SCS Tracking y (m) Entries/mm cut on s ----cut on stk ----cut on thn SCS x at stk Z(686) SCS x at stack z (m) Entries/mm cut on s ----cut on stk ----cut on thn SCS y at stk Z(686) SCS y at stack z (m) Dustin McNulty Shower Max Detector Plans for MOLLER 14

16 4 1 1 Jan8 Testbeam Pulse Height Dists Thin Det (Raw, 686, trig s) hthin_raw Entries 949 Mean.8 RMS 9. Stack Det (Raw, 686, trig s) hstk_raw Entries 949 Mean 1.6 RMS Thin Det (ped sub, 686, trig s) hthin 4 Entries 8915 Mean.6 5 RMS χ / ndf 9. / 76 5 Lwidth 1.9 ±. MPV 4.76 ±.1 Integral 881 ± GSigma 5.94 ± Stack Det (ped sub, 686, trig s) 9 Entries Mean RMS χ / ndf 6.4 / 7 Lwidth 1.69 ±.1 5 MPV 14.6 ±. 4 Integral 6445 ± 8.8 GSigma 4.7 ±.6 1 hstk Sun Jul :17:19 8 Stack performance: 51.7/144 =.58 (raw) Dustin McNulty Shower Max Detector Plans for MOLLER 15

17 6 5 4 Jan8 Testbeam Pulse Height Dists Thin Det (Raw, 676, trig stk) hthin_raw Entries 175 Mean 19.6 RMS Stack Det (Raw, 676, trig stk) hstk_raw Entries 175 Mean 45.1 RMS Thin Det (ped sub, 676, trig stk) Entries Mean 6.58 RMS 11.8 χ / ndf 14. / 66 Lwidth ±.18 MPV.85 ±.4 Integral 8.84e+4 ± 1 GSigma 5.98 ± hthin Sun Jul :59:1 8 Stack Det (ped sub, 676, trig stk) 1 Entries 175 Mean RMS χ / ndf / 4 Lwidth.464 ±.55 6 MPV 11. ±. Integral 1.71e+5 ± GSigma 46.8 ±. hstk Dustin McNulty Shower Max Detector Plans for MOLLER 16

18 ' $ January 8 PREx detectors tests, comparison with simulations Thin 5mm Thin 1mm exp: 5±17(4%) exp: 9±(4%) sim: 56.8±7.7(14%) sim: 19.±11.(1%) Stack exp: 44±15(5%) sim: 58.±14.5(6%) Number of Cherenkov photons reaching PM NPE=.Nph (<QE>=.) In panels below widths of gaussian fits to the simulated Nph distributions (red lines) are corrected for the PMT resolution according to the formula (for the used PMTs measured value of the δq is.): exp:.71±.4(4%) pc exp: 1.1±.1(4%) pc exp: 7.74±.71(5%) pc sim:.8±.6(%) pc sim: 1.5±.6(4%) pc sim: 9.61±.68(8%) pc PM output charge (pc) & Dustin McNulty Slide from Piotr Shower Max Detector Plans for MOLLER % 17

19 8 Testbeam Summary Results for stack detector were lack-luster: 5% relative width Why? Because energy too low? Or some other reasons?...det alignment, e trajectories,... Results do not agree with simulations...why? Would further analysis and/or simulation refinement help here? Dustin McNulty Shower Max Detector Plans for MOLLER 18

20 Plans for MOLLER Shower Max Start with 8 stack experience Apply benchmarked qsim optical MC to the stack Try to reproduce Piotr s simulation results Study dependence on numbers and thicknesses of W and Quartz, distance from pmt, and beam energy Modify stack/lg/pmt geomerty for MOLLER; repeat studies Other considerations/questions for MOLLER: 9 LG versus 15 (or 45 ) LG Frame support struct: space constraints, φ segmentation, staggered to eliminate gaps or use trapezoidal quartz? What is optimal design for - 8 GeV electrons Need to worry about sensitivity to pions Stray electrons, spashback,...what else? Build protype and test with beam (at SLAC?) Dustin McNulty Shower Max Detector Plans for MOLLER 19

21 Crude Design based on Peiqing s work and PREx/Mainz testbeam experience Dustin McNulty Shower Max Detector Plans for MOLLER

22 Another Crude Design...but has problems Dustin McNulty Shower Max Detector Plans for MOLLER 1

23 Extra Slides Dustin McNulty Shower Max Detector Plans for MOLLER

24 θ and φ Spectra (Before Q change) Entries SCS Tracking θ (run676) ----cut on s ----cut on stk ----cut on thn θ (deg) Entries SCS Tracking φ (run676) ----cut on s ----cut on stk ----cut on thn φ (deg) Dustin McNulty Shower Max Detector Plans for MOLLER

25 x and y Spectra (Before Q change) Entries/mm SCS Tracking x (676) ----cut on s ----cut on stk ----cut on thn Entries/mm SCS Tracking y (676) ----cut on s ----cut on stk ----cut on thn SCS Tracking x (m) SCS Tracking y (m) Entries/mm cut on s ----cut on stk ----cut on thn SCS x at stk Z(676) Entries/mm cut on s ----cut on stk ----cut on thn SCS y at stk Z(676) SCS x at stack z (m) SCS y at stack z (m) Dustin McNulty Shower Max Detector Plans for MOLLER 4

26 Sim. and Exp. (ISU thin quartz cosmic tests) Dustin McNulty Shower Max Detector Plans for MOLLER 5