Triple GEM Operation

RD51 GroupSaha Institute of Nuclear Physics

14 February, 2014

13th RD51 Collaboration Meeting 207-02-2014

Drift (3mm)

Transfer 1 (1mm)

Transfer 2 (2mm)

Induction (1mm)

Cathode

GEM1

GEM2

GEM3

Anode

10M

10M

10M

10M

1.0M

0.1M0.1M

2.2nF2.2nF

Triple-GEM Connection

Filter

Divider

0.1M

0.55M

1.0M

0.5M

1.0M

0.4375M

1.0M

HV

4 Readout Sectors

HV (V)

I (A)

Drift(V)

G1T(V)

G1B (V)

G1(V)

G2T (V)

G2B(V)

G2(V)

G3T(V)

G3B (V)

G3(V)

Gain

4750 820 4340 3550 3150 400 2330 1956 374 1141 800 341 27614700 811 4290 3510 3110 400 2300 1933 367 1134 790 344 2565

4650 803 4240 3470 3080 390 2270 1911 359 1121 781 340 2347

4600 794 4190 3430 3040 390 2250 1890 360 1109 772 337 2105

4550 786 4150 3400 3010 390 2220 1870 350 1097 764 337 1844

4500 777 4100 3360 2980 380 2200 1849 351 1085 755 330 1577

4450 768 4050 3320 2945 375 2175 1829 346 1073 747 326 1338

4400 760 4010 3285 2910 375 2150 1808 342 1061 739 322 1129

4350 751 3965 3250 2880 370 2125 1787 338 1048 730 318 948

4300 742 3920 3210 2840 370 2100 1767 333 1036 721 315 821

Voltage Current Tabulation

13th RD51 Collaboration Meeting 407-02-2014

Pulse Height Spectra for 4 Readout Sectors

HV = 4450 V

Without RC filter

13th RD51 Collaboration Meeting 507-02-2014

Pulse Height Spectra For Different HV

4450 V 4550 V

4650 V 4750 V

With RC filter

13th RD51 Collaboration Meeting 607-02-2014

Gain Variation with High Voltage (before RC filter)

• Assumed that the voltage divider configurations are same in both the cases !

• No idea whether the HV in CMSGEM is before or after the RC filter !