An Analy alysis is of of CD CDC C cos osmic ic-ra ray test 2017.12.28 Year End presentation Kuno Lab M2 Kaori Okinaka 2017/12/28 year end presentation 1
Over view � ks � 1. Introduction • COMET experiment • COMET CDC • Cosmic ray test 2. XTCurve (relation between drift Time and drift distance) 3. Spatial resolution 4. Hit efficiency 5. Summary 2 2017/12/28 year end presentation
COMET Phase-I COMET is experiment to detect ! → # conversion which is one of the charged lepton flavor violation(=CLFV). We target to achieve signal sensitivity 3×10 )*+ for Phase-I. u Standard model ( ! → #, ) BR: ~10 )+. u New Physics BR: ~10 )*+ Search for new physics beyond standard model We use Cylindrical Drift Chamber (CDC) for COMET Phase-I to detect signal of ! → # conversion 2017/12/28 year end presentation 3
COMET CDC � requirement for COMET CDC � � Gas Chamber � • Momentum resolution< 200keV/c (for electron of 105MeV/c) Ground BG signal • Spatial resolution < 200µm +HV e ! ) / → # ) / ���������(�������� ����)�)������ �������������)���� Sense wire � COMET CDC � Material : Au plated W All stereo wire Ground # of wires: 4986 +HV Number of layer is 20 diameter of wire: 25 ! m (include 2 guard layers) 1.7m 8mm Field wire Gas ratio � He:i-C 4 H 10 =90:10 material: Al 8.4mm # of wires: 14562 magnetic field � 1T Size for cell of CDC Diameter of wire: 126 ! m 2017/12/28 year end presentation 4
Cosmic ray test Now we are checking performance for CDC by Cosmic ray test in KEK. [mm] <setup for cosmic ray test> <information from CDC> Applied HV 1750~1850V TDC : timing information ADC : charge information *Mainly data applied 1825V is used for detail analysis gas ratio He:i-C 4 H 10 90:10 (flow rate:90 CCM:10 CCM) �O [mm] Track example viewed from center plane of CDC requirement for CDC momentum resolution 200keV/c 1. Create XT for COMET CDC 2. Check spatial resolution 3. Check hit efficiency Setup I estimate these points. (view from center plane of CDC) 5 2017/12/28 year end presentation
Analysis Requirements for event I estimate for XT, spatial resolution and hit efficiency for each �G cell and each incident angle. I estimated event which meets P value for tracking>0.05 # of layers which has single hit >14 requirement for events. # of layers which has multi hits<2 XTCurve Spatial resolution XT curve corresponds to the relation between drift I get σ of residual to understand spatial resolution. distance and drift time for CDC. Because every cell has vary shape, XT relation is DCA =Distance of Closest Approach different for each cell. XT Curve for testlayer 10 XT Curve for testlayer 10 Residual =radius of drift circle – |DCA| 10 6 DCA [mm] <Hit condition for XT Curve> 8 5 6 • Hit on the test layer 4 4 • P value of tracking>0.05 = >?@ABCDE ＝ spatial resolution ＋ Tracking error 2 residual(DCA5~6mm) iteration3 residual(DCA5~6mm) iteration3 0 3 • residual -0.5mm~0.5mm − 2 900 entry 2 − 4 800 − 6 1 � Fitting function for XT � − 8 700 − 10 0 0 100 200 300 400 500 600 700 600 driftTime [ns] 500 400 300 200 ! "#$%&' is switch timing for fitting function. 100 This value is got by fitting. 0 − 2 − 1.5 − 1 − 0.5 0 0.5 1 1.5 2 residual[mm] 6 2017/12/28 year end presentation
F dependence for XT ß Definition of angle F Phi is incident angle of track for cell. Y’ The electric field is different between around center of cell ! and edge of cell. positive X’ So, XT Curves are also different depends on incident angle. +HV I checked XT difference from checking F dependence for XT Electric field simulated Ground by garfield Cell_ distribution Cell_ φ φ distribution Readout area is left side of SETUP entry/bin CDC and cell lean to right. 20000 18000 So, F distribution lean to 16000 positive value. 14000 F 12000 10000 8000 6000 4000 2000 0 − 40 − 30 − 20 − 10 0 10 20 30 40 degree 7 2017/12/28 year end presentation
F dependence for XT Preliminaly This is XT curve corresponds to the relation between drift distance and drift time. slope of XT is more steep angle when |F| is larger . It means drift velocity is faster for large F . Its consistent with electric field studied by simulation. 8 2017/12/28 year end presentation
Spatial resolution -HV dependence- ß I estimated spatial resolution for each layers from σ of residual . Requirements for event σ value is large around guard layer. �G Its because tracking error is bigger than middle layer. P value for tracking>0.05 # of layers which has single hit >14 = >?@ABCDE ＝ spatial resolution ＋ Tracking error # of layers which has multi hits<2 spatial resolution for each layer spatial resolution for each layer 0.4 sigma[mm] run175 @1850V run171 @1825V run161 @1800V run183 @1775V run181 @1750V 0.35 0.3 0.25 0.2 required 0.15 0 2 4 6 8 10 12 14 16 18 layer The data which applied 1800V~ meets requirement of spatial resolution (= >?@ABCDE <200µm) 12 2017/12/28 year end presentation
Hit efficiency -HV dependence- ß I estimated hit efficiency for each layers. Requirements for event �G STUV#W XY #Z#S[ \ℎ^_ℎ ℎ`a ℎ^[ (residual < Q=) Hit efficiency = P value for tracking>0.05 number of events meet the requirements # of layers which has single hit >14 # of layers which has multi hits<2 Hit efficiency per layer Hit efficiency per layer 1 Hit efficiency 0.95 0.9 0.85 0.8 run175 @1850V run171 @1825V run161 @1800V run183 @1775V run181 @1750V 0.75 0 2 4 6 8 10 12 14 16 18 layer The data which applied 1800V~ reached about 95% for hit efficiency. From this value and tracking efficiency, we are going to set the definition of hit which use for tracking. 13 2017/12/28 year end presentation
Summary • COMET is experiment to detect ! → # conversion . • We are checking performance for CDC which detect mu-e conversion in COMET Phase-I. • I estimated XT , spatial resolution, hit efficiency. • I checked that there is F dependence for XT. H×F dependence is also seen by difference of XT. • • I can check HV dependency for hit efficiency and spatial resolution. � When applied HV is over 1800V, spatial resolution meets the conditions for CDC. (CDC requirement : spatial resolution < 200µm) � The data which applied higher than 1800V reached about 95% for hit efficiency. -> from these result , we are going to set the definition of hit for tracking , applied HV. 14 2017/12/28 year end presentation
Back up 15 2017/12/28 year end presentation
F dependence for XT ß XT Curve for φ ~-7.5 degree XT Curve for φ -7.5~-2.5 degree XT Curve for φ -2.5~2.5 degree XT Curve for φ 2.5~7.5 degree 10 10 10 10 DCA [mm] 100 DCA [mm] 100 DCA [mm] 100 DCA [mm] 100 h_XTp0 h_XTp0 h_XTp1 h_XTp1 h_XTp2 h_XTp2 h_XTp3 h_XTp3 Entries Entries 4280 4280 Entries Entries 59927 59927 Entries Entries 303009 303009 Entries Entries 464826 464826 Mean x Mean x 174 174 Mean x Mean x 173.9 173.9 Mean x Mean x 176.6 176.6 Mean x Mean x 190 190 8 8 8 8 90 90 90 90 Mean y Mean y 3.999 3.999 Mean y Mean y 4.025 4.025 Mean y Mean y 4.072 4.072 Mean y Mean y 4.263 4.263 RMS x RMS x 139.3 139.3 RMS x RMS x 133.4 133.4 RMS x RMS x 134.2 134.2 RMS x RMS x 145.7 145.7 RMS y RMS y 2.418 2.418 RMS y RMS y 2.363 2.363 RMS y RMS y 2.38 2.38 RMS y RMS y 2.441 2.441 6 6 6 6 80 80 80 80 4 4 4 4 70 70 70 70 2 60 2 60 2 60 2 60 0 0 0 0 50 50 50 50 2 2 2 2 − 40 − 40 − 40 − 40 − 4 30 − 4 30 − 4 30 − 4 30 6 6 6 6 − 20 − 20 − 20 − 20 − 8 − 8 − 8 − 8 10 10 10 10 10 10 10 10 − 0 − 0 − 0 − 0 0 100 200 300 400 500 600 700 0 100 200 300 400 500 600 700 0 100 200 300 400 500 600 700 0 100 200 300 400 500 600 700 driftTime [ns] driftTime [ns] driftTime [ns] driftTime [ns] XT Curve for φ 7.5~12.5 degree XT Curve for φ 12.5~17.5 degree XT Curve for φ 17.5~22.5 degree 10 10 10 100 100 100 DCA [mm] DCA [mm] DCA [mm] h_XTp4 h_XTp4 h_XTp5 h_XTp5 h_XTp6 h_XTp6 Entries Entries 353371 353371 Entries Entries 131501 131501 Entries Entries 20914 20914 Mean x Mean x 199.6 199.6 Mean x Mean x 203.2 203.2 Mean x Mean x 202.1 202.1 8 8 8 90 90 90 Mean y Mean y 4.414 4.414 Mean y Mean y 4.513 4.513 Mean y Mean y 4.458 4.458 RMS x RMS x 150.2 150.2 RMS x RMS x 144.7 144.7 RMS x RMS x 148 148 RMS y RMS y 2.429 2.429 RMS y RMS y 2.315 2.315 RMS y RMS y 2.345 2.345 6 6 6 80 80 80 4 4 4 70 70 70 2 60 2 60 2 60 0 0 0 50 50 50 − 2 − 2 − 2 40 40 40 − 4 30 − 4 30 − 4 30 6 6 6 − 20 − 20 − 20 − 8 − 8 − 8 10 10 10 10 10 10 − 0 − 0 − 0 0 100 200 300 400 500 600 700 0 100 200 300 400 500 600 700 0 100 200 300 400 500 600 700 driftTime [ns] driftTime [ns] driftTime [ns] 16 2017/12/28 year end presentation
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