TPC R&D status in Japan

T. Isobe, H. Hamagaki, K. Ozawa, and M. Inuzuka Center for Nuclear Study, University of Tokyo

Contents1. Development of a prototype TPC2. Basic Gas Test of pure CF43. Performance evaluation4. GEM development

19, Nov., 2003 TPC/HBD Upgrade Working Group Meeting

Development of a prototype TPC• A prototype TPC

– 30cm drift length, -30 kV HV– Readout from cathode pads

20 m anode wire• 13mm, 9.5mm, 6mm, 2.5mm pad• Designed as GEM can be mounted

– Three holes for LASER input

• Front End Electronics• Charge sensitive Pre-amp

– 300MHz bandwidth

• 100MHz 8bit FADC

Drift 34cm

-V

Readout

Drift region

Gain

Gain test setup

6*10^4• 5.9 keV X-ray from 55Fe

CF4 needs much higher voltage to detect the suitable signals.

CF4 characteristics• Drift velocity and longitudinal

diffusion were measured.– N2 LASER (λ=337nm)

• Attenuated for single electron source

• Input to 3 different positions

Gas condition20C,1 atmH2O = 100ppmO2 = 30ppm

Test system

10cm/μsec@900V/cm/atm

60μm

Performance of TPC

Energy loss

Schematic view of the beam test setup

• Beam Test at KEK(Jun. 2003)– e,π,p,d beam (0.5-2.0GeV/c )– readout with anode wire (no GEM readout)

• Measurement Topics– Position resolution

• 100μm resolution along the anode wire direction (2.5mm pad)• 500μm resolution in the drift direction

– Double Track Separation• Double track could be identified, when the difference in distance between

the tracks in the drift direction was more than 1.5cm

– Particle Identification• Estimate that it is able to identify the electron with p < 80MeV/c

– 5cm track length, 2 separation

Development of GEM• Two kinds of GEM are tested

– GEM from CERN• Sauli group• Wet etching• 100 GΏ between both electrodes

– GEM was made in Japan• Univ. of Tokyo and Fuchigami Co.• Plasma etching• 10 GΏ between both electrodes

CERN

Fuchigami CO.

Gain

*10^3[V]

P10

Ar-CO2

consistent with the results of CERN GEM

Next Plan to test GEM readout for TPC

Summary & Outlook• Achievements

– A prototype TPC was developed.– CF4 characteristics was investigated.

• 10cm/μsec drift velocity & 60μm longitudinal diffusion @E=900V/cm

– Total performance of TPC with CF4 gas was investigated. • achieved 100μm resolution along the wire direction

– GEM was developed using plasma etching method in Japan.

• Outlook– Install the GEM as TPC readout

• investigate the capability (next year)

– Other types of readout pads– Improve the Front End Electronics

• Applying for the high density signal (large band width)

Additional slides

CF4 signal

• 110n second rise time• ~10 points to obtain the

T0.– With 100MHz sampling

Position Resolution

Position resolution in the drift direction and along the anode wirewere investigated as a function of drift length, pad size and input angle.

100μm

Beam Test(2)

Drift direction

Along the wire

100μm

500μm

Position resolution

80MeV

Double Track

Energy loss