The first signal of GEM-TPC 2004/03/12 ODA, Susumu GEM check using X-ray source (55Fe) and P10 gas. GEM-TPC signal using P10 gas and LASER. GEM-TPC signal using CF4 gas and LASER. Preamplifier Pad shape

1. GEM check using X-ray source (55Fe) and P10 gas Setup (inside TPC) VGEM = 355 V VGEM = 334 V Main peak and escape peak were observed. I thought triple GEM worked well.

2. GEM-TPC signal using P10 gas and LASER VGEM = 350 V Edrift ~ 220 V/cm 1 2 3 LASER 1 2 3 LASER GEM-TPC signals from LASER were observed. GEM-TPC worked well in P10 gas.

1 2 3 4 ADC value of LASER signal increase with VGEM. Cosmic ray signal VGEM = 329 V Edrift ~ 230 V/cm 1 2 3 4

3. GEM-TPC signal using CF4 gas and LASER 1 2 3 4 Cosmic ray signal VGEM = 510 V mean – pedestal vs. VGEM LASER signal GEM-TPC worked well in also CF4 gas. GEM tripped at VGEM = 550 V. (gain~2x104) Edrift ~ 400 V/cm

4. Preamplifier Isobe-san type preamps.

I used this type preamp for above measurements.

5. Pad shape CERN, Karlsruhe Univ. etc. Carleton Univ. etc. 1.27 x 12.5 mm2 Carleton Univ. etc. 2 x 6 mm2　physics/0402054

* 1.5 x 10 mm2 ?? * Use 2FADCs or 3FADCs * Compare with rectangle and zigzag * X-direction resolution using 3 rows : X2-(X1+X3)/2 * Large pads for Drift velocity measurement