Analysis for J2 chamber Yousuke Kataoka (University of Tokyo) - - PowerPoint PPT Presentation

▶
analysis for j2 chamber
SMART_READER_LITE
LIVE PREVIEW

Analysis for J2 chamber Yousuke Kataoka (University of Tokyo) - - PowerPoint PPT Presentation

Aug 15, 2022 176 likes •364 views

11 / 12 / 2012 Micromegas weekly meeting Analysis for J2 chamber Yousuke Kataoka (University of Tokyo) Atsuhiko Ochi, Yuki Edo (Kobe University) 1 Introduction J2 chamber is made in Kobe (with Raytech) Print screen 400um pitch Z1 Z2

slide-1
SLIDE 1

Analysis for J2 chamber

Yousuke Kataoka (University of Tokyo) Atsuhiko Ochi, Yuki Edo (Kobe University)

11 / 12 / 2012 Micromegas weekly meeting

1

slide-2
SLIDE 2

Introduction

  • J2 chamber is made in Kobe (with Raytech)

– Print screen 400um pitch – 1 dimentional readout (2d for Z1,Z2) – 100um mesh gap (128um for Z1,Z2) – 15mm drift gap (5mm for Z1,Z2)

  • H6 test beam 19~25 Nov.

– Run 8325~8500 by APV – 0,+10,+20,+30,+40 degree – HV_strip, HV_drift scan – some time with Z1, Z2

J2

Tmm5,6

Z1 Z2

Tmm2,3

beam

2

slide-3
SLIDE 3

Chamber efficiency

at least 1 cluster on J2 1 cluster on Tmm2,3,5,6 chamber efficiency =

conditions

  • ZS factor = 0.8
  • reject 1 strip cluster
  • require cluster Q > 100
  • allow gap up to 12 in cluster
  • J2 reach >99% at 430V, Zebra at 550V
  • The difference come from mesh gap, drift gap, 1D or 2D
  • drop at larger angle due to smaller Q / strip

3

slide-4
SLIDE 4

Strip efficiency

strip efficiency == strip at center hit ?

At larger angle, some drops of strips within cluster

  • even when chamber efficiency is 100%,

strip efficiency could be much low  impact on perfomance 40 30 20 Number of hits (40 degree)

4

slide-5
SLIDE 5

Comparison to Garfield

APV25 CR-RC shaper τ = 50ns t/50 x exp(- t/50) 25ns bin 400um bin

5

  • 1. Garfield 9 (fortran)
  • 2. assign gas gain
  • 3. assign shape
  • 5. digitize
  • 4. give jitter

~51 electrons (5mm,0 deg.)  drift timing &position PDF from Garfield

  • 6. threshold

T  T + random(25ns) X  X + random(profile) basically every plots (full simulation)

  • 7. compare to data

threshold for charge ~ strip efficiency

slide-6
SLIDE 6

Cluster width

good agreements wider than Zebra

6

assume 100% strip effi.

slide-7
SLIDE 7

Timing width

drift velocity

7

T_qmax roughly consistent (need to check) width [Tbin]

slide-8
SLIDE 8

Position resolution

Center = (left + right) /2. J2 x 400um – (Tmm2 + Tmm3 + Tmm5 + Tmm6)/4 x 250um / cos(theta) resolution = sigma / sqrt(1+1/4)

8

after introducing strip efficiency, agreement is good

slide-9
SLIDE 9

Time resolution

Constant fraction threshold = 50% J2 x 25ns – (Tmm2 + Tmm3 + Tmm5 + Tmm6)/4 x 25ns resolution = sigma / sqrt(1+1/4) CFD=25% CFD=50% delay was not enough probably optimistic

9

pile up effect at 0 degree (CDF not work)

slide-10
SLIDE 10

TPC Angle

J2(0) … 0.100  1.9 degree J2(10) … -0.639  12.1 J2(20) … -1.097  20.2 J2(30) … -1.678  29.4 J2(40) … -2.386  38.7 Z1(20) … -1.296  23.5 Z2(20) … -1.290  23.4

~ 1 degree 4.7cm/us

10

wide gap is good for TPC

slide-11
SLIDE 11

Summary

  • J2, Z1, Z2 are working fine

and in good agreement with Garfield simulation (many points need to be understood …)

  • strip efficiency affects performance,

so higher voltage (lower threshold) is better (not just chamber 100% efficiency)

  • wider drift gap (wrt. pitch) is not good for strip efficiency and

clustering, but better for TPC reconstruction

11

slide-12
SLIDE 12

backup

12

slide-13
SLIDE 13

13

slide-14
SLIDE 14

14

slide-15
SLIDE 15

CFD=25% log scale CFD=50% CFD=25% CFD=25% (log) CFD=50% (log)

15

slide-16
SLIDE 16

16

slide-17
SLIDE 17

Time resolution

Constant fraction threshold = 25% J2 x 25ns – (Tmm2 + Tmm3 + Tmm5 + Tmm6)/4 x 25ns resolution = sigma / sqrt(1+1/4)

17