Development of a Vertex Chamber with using GEM

Yutaka Mizoi

Osaka Electro-Communication University

Colleagues; Tomokazu Fukuda, Shizu Minami, and Wataru Imoto

Workshop for MPGD at Kyoto University, 2004.Dec.3-4.

Contents

1) Experiments2) Cylindrical Drift Chamber System3) Design of Vertex Chamber4) Schedule and etc.5) Other Cylindrical GEM Detectors

1) Experiments

I) Study of Double- Hypernuclei @ J-PARC　 a) Confirm the existence of 4H　

　　 b) Search for 5H

II) p + n p + @ RCNP

)114.3MeV/c~( HeH

p)HHe(

104MeV/c)~( HeH

33

3*4

*44 ΛΛ

p

p

-

-

π

π

97MeV/c)~( pHeHe

116MeV/c)~( HeH34

44 ΛΛ

p

p-

-

π

π

MeV/c)99~( pHeHe

134MeV/c)~( HeH-45

55

p

p-π

MeV/c)9.132~( HeH

100MeV/c)~( pHH-44

45

p

p-π

p +

High vertex resolution is required for tracing two- tracks.

High counting rate from background.

2) Cylindrical Drift Chamber System (CDS)

Vertex Chamber

Cylindrical Drift Chamber

Hodoscopes

Solenoid Magnetk-

k+

Vertex DeterminationMomentum AnalysisParticle Identification

3) Design of Vertex Chamber

Development History

E906@BNL in 1998:Previous CDS designed by J. P. Nakano, et al. for experiments.No Vertex Chamber, Z-Chamber outer of CDC did not be used due to...

E961@BNL accepted in 2002:A newly developed vertex chamber will be installed in the previous CDS,but .......

Recently, design study of a new CDS has been started for J-PARC.

E961 E906

Target (density) LiH (0.83 g/cm3) 9Be (1.85 g/cm3)

Target size 5.08x1.225x20 cm3

5.08x1.225x15.24 cm3

Target position (0, 0, 27.3) cm (0, 0, 0)

CDS acceptance 62% of 4 55% of 4 (60<<146) (71%)

K+ acceptance 69 msr 29 msr *

Z 0.8 mm rms 3 mm rms

p 2.4 MeV/c rms 4.3 MeV/c rms

* The upper 4 elements of FP were excluded from trigger in E906.

Results of GEANT simulationsResults of GEANT simulationsHotchi

w/o vertex chamber w/ vertex chamber

deca

ys

Dou

ble

s

ign

als

Distance of Closest Approach (cm)

DCA<2cm DCA<0.8cm

Hotchi

Required dimension : ~ 100 mm x 315 mm

New z-vertex chamberNew z-vertex chamber

Two Promising Designs - Anode wire or GEM ?

Read-out Strip Electrode

Anode Wire

Field WireGEM foil x 2~3

-

-Anode

Strip

Z position

Strip

GEM

Z

R

Anode-wire configuration;Well known structure,One-dimensional tracking,Wire-tension stress... GEM-foil configuration;

Two-dimensional tracking,No mechanical Stress,High counting rate,Unknown structure,Mass density......

(Inner or Outer is another option.)

Design of the Read-out Strip-Electrode SheetPolyimide 25m+Cu 18m X 3 layers, 3mmX129.3mm Strip with 0.2mm gap X 96 strips

３２２．２（ストリップ両端間）

ｽﾄﾘｯﾌ長゚

129.

3

GN

D幅

139.

3

ｽﾄﾘｯﾌﾟ1番ﾋ ﾝ゚ ｽﾄﾘｯﾌﾟ

96番ﾋ ﾝ゚10 20 30 40 50 60 70 80 90

GNDS1

S49

S51

S95

GND

GND

GND

奇数ピン番のみ 昇順配置

偶数ピン番のみ 降順配置

48 51～ ﾋ ﾝ゚はNC

1 4 NC～ ﾋ ﾝ゚はGNDS96

S52

S50

S2

GND

GND

GND

外形－取付穴 3.0（マイナス公差要）

３５２．０〔＝ＧＮＤ寸＝チェンバー寸法３５５．０ ×－（０．５ ２）〕

外形全長 ４７０．０

チェンバー取付用スルホール×Ｐ１５．０ ２２（２３個）＝３３０．０

0.50.5

Required Design for GEM

i) Gas gain ? 103~4 ~ achievable with single GEM foil.ii) Multi GEM ? for safety margin; two or three GEMs, but thickness is another problem.iii) Size ? 30cm X 15cm ~ available in CERN workshop.

4) Development Schedule1) Anode-wire configuration Test in a planer geometry will start soon. A test bench with anode wires will be ready at KEK in December. Thanks for Sekimoto-san.

2) GEM-foil configuration Three 10cm2-GEM foils made in CERN have just arrived. A test bench in a planer geometry is now under designing.

Prof. Sauli gave us a large-area (junk) GEM foil with 31cmX31cm. A mechanical test for forming a GEM foil into cylindrical shape will be performed in this FY.

5) Other Cylindrical GEM Detectors

I) BoNuS Detector@Jefferson Lab. Howard Fenker, et al.

100MeV/c)( pnede -- ppBoNuS=Barely off shell Nuclear Structure

Radial TPC 20cm x 8-12cm

http://www.jlab.org/~hcf/bonus/

II) TACTIC@TRIUMF, Pierre-André Amaudruz, et al.

pBepBe

BnHeLi77

1148

TACTIC=TRIUMF Annular Chamber for Tracking Identification of Charged particles

Nuclear-Astrophysical Reactions

http://tactic.triumf.ca/

Summary

Which is better for the present purpose,GEM or Anode-wire configuration?We will continue study to resolve it.

Anyway, we will develop a cylindrical GEM detector.It is a very attractive challenge itself.

A CDC will be replaced by a cylindrical GEM TPC !?