Stopping Target Optimization for COMET Phase II Giorgi - PowerPoint PPT Presentation

Stopping Target Optimization 
 for COMET Phase II Giorgi Kumsiashvili M2 Year-end Presentation 2019 1

COMET Phase II Beamline Electron Spectrometer Production 
 Muon 
 Target Stopping 
 Target Detector 
 Region Torus 1 Torus 2 2

Original Target Design sqrt(pxa[0]**2+pya[0]**2+pza[0]**2) {hit0} htemp htemp Entries Entries 73341 73341 45000 Mean Mean 101.8 101.8 Std Dev 11.76 Std Dev 11.76 40000 35000 30000 Target Radius 100mm 25000 Beam Blocker - Vacuum 20000 DIO Blocker - Vacuum 15000 Default Gradient Mag. Field 10000 5000 0 0 20 40 60 80 100 sqrt(pxa[0]**2+pya[0]**2+pza[0]**2) 3

Signal Electrons Signal Electrons that are 
 later accepted by the detector 4

Distribution in Straw Tracker 5

Test Designs 1st Disk - 50mm, 9th - 100mm, 17th - 50mm 1st Disk - 100mm, 9th - 50mm, 17th - 100mm 1st Disk - 50mm, 17th - 150mm 1st Disk - 150mm,17th - 50mm 6

Distributions In Straw Tracker 50mm-100mm-50mm 50mm-150mm xa:ya {hit0&&hit1&&hit2&&hit3&&hit4&&xa>10000} xa:ya {hit0&&hit1&&hit2&&hit3&&hit4&&xa>10000} 11600 2200 xa xa 2000 2000 11400 11400 1800 1800 1600 11200 11200 1600 1400 1400 11000 11000 1200 1200 10800 10800 1000 1000 800 800 10600 10600 600 600 10400 10400 400 400 10200 200 200 10200 0 0 − 800 − 600 − 400 − 200 0 200 400 600 800 − 800 − 600 − 400 − 200 0 200 400 600 800 ya ya xa:ya {hit0&&hit1&&hit2&&hit3&&hit4&&xa>10000} xa:ya {hit0&&hit1&&hit2&&hit3&&hit4&&xa>10000} 100mm-50mm-100mm 150mm-50mm xa xa 2000 1800 11400 11400 1800 1600 11200 11200 1600 1400 1400 11000 1200 11000 1200 1000 10800 10800 1000 800 800 10600 10600 600 600 10400 400 10400 400 200 10200 200 10200 0 0 − 800 − 600 − 400 − 200 0 200 400 600 800 − 800 − 600 − 400 − 200 0 200 400 600 800 7 ya ya

Momentum 50mm-100mm-50mm 50mm-150mm sqrt(pxa[0]**2+pya[0]**2+pza[0]**2) {hit0} sqrt(pxa[0]**2+pya[0]**2+pza[0]**2) {hit0} htemp htemp htemp htemp Entries Entries 74078 74078 45000 Entries Entries 72286 72286 Mean Mean 102.3 102.3 Mean Mean 102 102 45000 Std Dev 10.88 Std Dev 10.88 40000 Std Dev 11.22 Std Dev 11.22 40000 35000 35000 30000 30000 74.07% 72.28% 25000 25000 20000 20000 15000 15000 10000 10000 5000 5000 0 0 0 20 40 60 80 100 0 20 40 60 80 100 sqrt(pxa[0]**2+pya[0]**2+pza[0]**2) sqrt(pxa[0]**2+pya[0]**2+pza[0]**2) 100mm-50mm-100mm 150mm-50mm sqrt(pxa[0]**2+pya[0]**2+pza[0]**2) {hit0} sqrt(pxa[0]**2+pya[0]**2+pza[0]**2) {hit0} htemp htemp htemp htemp 45000 Entries Entries 74059 74059 Entries Entries 72908 72908 Mean Mean 102.2 102.2 40000 Mean Mean 101.9 101.9 40000 Std Dev 11.22 Std Dev 11.22 Std Dev 11.91 Std Dev 11.91 35000 35000 30000 30000 74.05% 25000 25000 72.9% 20000 20000 15000 15000 10000 10000 5000 5000 0 0 0 20 40 60 80 100 0 20 40 60 80 100 sqrt(pxa[0]**2+pya[0]**2+pza[0]**2) sqrt(pxa[0]**2+pya[0]**2+pza[0]**2) 8

Initial Distribution 100’000 Electrons 9

Mu- Momentum in Disks In this example: Number of disks - 17 Disk radius - 100mm Momentum at StoppingTargetPhaseIITargetDisk_16 for mu- Momentum at StoppingTargetPhaseIITargetDisk_0 for mu- hMomentumAll_StoppingTargetPhaseIITargetDisk_16_13 hMomentumAll_StoppingTargetPhaseIITargetDisk_16_13 hMomentumAll_StoppingTargetPhaseIITargetDisk_0_13 hMomentumAll_StoppingTargetPhaseIITargetDisk_0_13 140 140 Entries Entries 4012 4012 Entries Entries 6222 6222 Mean Mean 48.72 48.72 51.39 51.39 Mean Mean Std Dev 15.27 Std Dev 15.27 Std Dev 14.04 Std Dev 14.04 120 120 100 100 Around 64.5% 80 80 60 60 40 40 20 20 0 0 20 40 60 80 100 120 140 160 180 200 20 40 60 80 100 120 140 160 180 Momentum (MeV/c) Momentum (MeV/c) Disk 1 Disk 17

Mu- Momentum in Disks In this example: Number of disks - 34 Disk radius - 100mm Momentum at StoppingTargetPhaseIITargetDisk_0 for mu- Momentum at StoppingTargetPhaseIITargetDisk_33 for mu- hMomentumAll_StoppingTargetPhaseIITargetDisk_0_13 hMomentumAll_StoppingTargetPhaseIITargetDisk_0_13 hMomentumAll_StoppingTargetPhaseIITargetDisk_33_13 hMomentumAll_StoppingTargetPhaseIITargetDisk_33_13 Entries Entries 6374 6374 Entries Entries 2374 2374 140 140 Mean Mean 51.32 51.32 Mean Mean 49.22 49.22 Std Dev 14.18 Std Dev 14.18 Std Dev 15.59 Std Dev 15.59 120 120 100 100 Around 37% 80 80 60 60 40 40 20 20 0 0 20 40 60 80 100 120 140 160 180 0 20 40 60 80 100 120 140 160 180 200 Momentum (MeV/c) Momentum (MeV/c) Disk 1 Disk 34

Summary and future work • The original muon stopping target design is not optimal. • Test target designs yielded marginal improvements. There is a need to obtain 
 realistic muon stopping distribution in target disks. (in progress) • Significant number of Muons go through the target disks and downstream. What’s next.. • Run larger scale simulations for usage in signal acceptance tests. • See if using 34 target disks hurt signal acceptance or not. (Smaller disks?.) Thank you for your attention! 12

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BACKUP 14

Initial Distribution (That hit all 5 stations) 72’908 Electrons 15

COMET Phase II Background Estimations From COMET Phase II note 18

Decay-in-orbit • DIO Spectrum Linear Scale Logarithmic Scale From Czernicki’s Calculations 19

Analysis Workflow Simulation Using ICEDUST Raw Output .root file Analysis of Simulation output 
 Analysed .root file (TTree) using Analysis Code Drawing Histograms and calculation 
 using CERN ROOT 20

Signal and DIO Simulation • 500000 Muons uniformly distributed in 17 disks • Beam Blocker removed • DIO Blocker removed Initial electron with 105MeV The number of stopped muons in each disks 29616 29573 29563 29601 29594 29665 29466 29444 29426 29357 29455 29492 29269 29289 29371 29427 29369 29242 29207 29249 29300 29357 29346 29068 29197 29152 29168 29161 29111 29096 htemp htemp htemp 28832 30000 28342 30000 Entries 495730 Entries 495730 Entries 495730 27360 27278 Mean Mean Mean 1435 1435 1435 htemp htemp htemp RMS RMS RMS 244.8 244.8 244.8 Entries 500000 Entries 500000 Entries 500000 25000 25000 Mean Mean Mean 1437 1437 1437 RMS RMS RMS 245.6 245.6 245.6 20000 20000 15000 15000 10000 10000 5000 5000 2164 996 0 2 2 1 2 5 2 1 1 1 1 3 2 2 3 3 2 1 1 2 3 1 1 4 2 2 4 3 1 3 3 2 2 3 2 1 3 4 1 4 2 2 2 2 2 1 1 3 2 2 1 1 3 1 3 3 2 2 1 1 2 1 1 0 1000 1200 1400 1600 1800 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 lastposz iniposz 21

DIO Electrons 22

DIO Distribution in Spectrometer Plots by Wu Chen 23

DIO Spectrum Analysis DIO 2017 DIO Hist dio2017 dio2017 h1 h1 − 13 10 Entries Entries 2200 2200 Entries Entries 260000 260000 Mean Mean 99.88 99.88 Mean Mean 101.1 101.1 14 − 10 Std Dev 0.6887 Std Dev 0.6887 Std Dev Std Dev 0.571 0.571 10 − 10 − 15 10 16 − 10 11 − 10 17 − 10 18 − 10 − 12 10 − 19 10 20 − 10 13 − 10 21 − 10 − 22 10 − 14 10 − 23 10 − 24 10 100 101 102 103 104 105 100.5 101 101.5 102 102.5 103 103.5 104 104.5 105 Momentum [MeV/c] From Czarnecki’s Calculations DIO Spectrum recorded in the Straw Tracker DIO Spectrum with logarithmic scale 25

Smeared DIO DIO Spectrum smeared with a Gaussian 
 with sigma of 150 KeV DIO Hist h1 h1 Entries Entries 260000 260000 Mean Mean 101.1 101.1 Std Dev Std Dev 0.571 0.571 10 − 10 11 − 10 12 − 10 13 − 10 − 14 10 100.5 101 101.5 102 102.5 103 103.5 104 104.5 105 Big thanks to Chen Wu 
 MeV/c for helping with the code! 26

Acceptance and Improvement factors 28

Sensitivity 29

Stopping Rates 30

DIO Momentum Distribution on each straw station 31