GEM and Sci. data and measuurements

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Counting Experiemnt using tennelec tc 534

All the counting was done by one scale tennelec tc 534.

Discriminator setup for GEM and PMT's

The counting period is 5 min for all the discriminator threshold measurements unless it is differently reported for a specific measurement.

GEM (amplified 15) without source


Voltage (V) Number of Counts (5min) Average ( /min)
3.0 9 , 16, 26, 32, 46 8.5 [math]\pm[/math] 0.5
2.5 62, 138, 208, 267, 329 66.7 [math]\pm[/math] 3
2.0 259, 618 (2.5min), 767, 1001, 1241 253 [math]\pm[/math] 5
1.9 1030, 2100, 3200, 4300, 5391 1002 [math]\pm[/math] 110
1.8 20667 20667


GEM (amplified 15) with source


Voltage (V) Number of Counts (5min) Average ( /min)
2.5 14,23,43,68,77 [math]\pm[/math] 3
2.0 116,248,391,513,640 [math]\pm[/math] 3
1.8 1674, 3350, 5037, 6680,8385
1.7 22200
1.6 57000
1.5 349000
GEM (amplified 15) without source ortec 875
Voltage (V) Number of Counts (5min) Average ( /min)
2.5 14,23,43,68,77 [math]\pm[/math] 3
2.0 115,262,390,508,646 [math]\pm[/math] 3
1.8 3650, 7650, 11350, 14550,17938
1.7 22200
1.6 57000
1.5 349000
PMT (R)


Voltage (V) Number of Counts (5min) Average (/min.)
1.00 87, 178, 254, 337, 430 86 [math]\pm[/math] 2
0.7 219,410, 585, 768, 977 203[math]\pm[/math] 12
0.35 441, 941 (2.1min.), 1383, 1853, 2354 453 [math]\pm[/math] 11
0.30 750(1.5min), 1012, 1551, 2050, 2573 509[math]\pm[/math] 8


PMT (L) (amplified)


Voltage (V) Number of Counts (5min)
2.0 56, 110, 171, 234, 290 57[math]\pm[/math]2
1.0 263, 484, 737, 978, 1233 248[math]\pm[/math] 10
0.6 497, 1055,1632, 2114, 2655 524[math]\pm[/math]20
0.25 945,1866,2787, 3676,4643 932[math]\pm[/math]11

Counting the coincidence for the PMT's

The discriminator setup is 0.7 and 1.0 V for the Left and the right PMT successively.

Without Source
Start Date Time End Date Time Duration (min.) Number of Counts Count rate (cout./s) Notes
05/08/14 17:55 05/08/14 11:32:00 325 27120 1,4 Daylight
05/08/14 11:32:00 05/09/14 06:26:00 739 61825 1.4 overnight
05/09/14 06:26:00 05/09/14 13:54:00 1187 99300 1.4 Daylight
05/09/14 13:54:00 05/09/14 21:18:00 1631 136290 1.4 Daylight
05/09/14 21:18:00 05/11/14 6:55 3648 301960 1.4

Counting GEM (2.7, 3.1kV)

GEM operating voltage is 2.7, 3.1V GEM and cathode successively, and the disc. threshold is 2.0 V.

Without source


Start Date Time End Date Time Number of Counts Duration (min.) Count Rate (cout./s) Notes
05/08/14 16:14:19 05/08/14 23:37:00 (311 from 330 less by 19) 42903 311 2.3 Daylight
05/09/14 23:37:00 05/09/14 06:18:00(731) 99196 712 2.3 overnight
05/09/14 06:18:00 05/09/14 13:50:00(1183) 162485 1164 2.3 Daylight
05/09/14 13:50:00 05/09/14 21:21:00(1633) 223301 1614 2.3 Daylight
05/09/14 21:21:00 05/11/14 06:57:00(3650) 472100 3631 2.2 weekend

Counting without a source (Background)

GEM and Sci. are in coincidence, GEM detector operating voltage is 2.7, 3.1V for GEM and cathode successively, both of the PMT's have 1kV input voltage.

The disc. setup is as determined in the previous measurements, the count rate is 0.001 /min for scintillator-GEM coincidence


Counting Experiemnt using 3 scales including tennelec tc 534

GEM Counts

Without Source
Counting Time (min.) Number of Counts Count rate (cout./min.) Notes
15 882 59


With Source
Counting Time (min.) Number of Counts Count rate (cout./min) Notes
120 7390 60 using the new counter ortec sophiia has only 1 cout/s
120 16565 138 change to the same counter used before for GEM ortec 875 without 2.3 count/s
433 37865 87 1.4 count/s, overnight
230 29618 1.29 2.1 count/s



increasing the voltage to 2.85 kV, and 3.45 kV

without source coicidence of the three is 25 when it counted for 283 min.

with a soruce 300 counts in 970 min. ,we may need to increase the voltage again.

Coincidence Scope pictures

First Coincidence using Widest timing gate (1 usec)

Source ON

I saw about 1 coincidence perr minute with the source

GEM Scint Coint 5-16-14 B.png GEM Scint Coint 5-16-14 A.png GEM Scint Coint 5-16-14 C.png


Coincidence rate with source ON


date Counting Time (min.) Triple Coincidence Counts Scint Coinc GEM singles PMT1 singles PMT2 singles
5/16/14 211.26 min 296 (1.27 Counts/Min) 2519870 (198 Hz) 429886 (34 Hz) 36822230(2.9 kHz) 41833?
5/17/14 1066.55 1531 (1.43 Counts/min) 12724200 (199 Hz) 2153491 OVERFLOW OVERFLOW
5/17/14 503.07 658 (1.3 counts/min) 5997670 (199 Hz) 1020620

The average counting rate for the first two measurements is 0.85 count/min, and for the last one 0.76 count/min., so the total average is 0.8 \pm 0.02 count/min.


Coincidence rate with source OFF


date Counting Time (min.) Triple Coincidence Counts Scint Coinc GEM singles PMT1 singles PMT2 singles comment
5/19/14 2218.08 550 (0.24 Counts/min) 330763 (149 Counts/min???) 3237254 5282644 54 3 29 GEM out of GAS and someone may have hit stop early on the clock (Time and Tiple coinc are correct)
5/19/14 76.37 14 ( Counts/min) 99415 (Counts/min) 24 158176 01 04 21 GEM out of GAS, GEM HV is on 2800:2500, change scaler for PMT2


GEM Scint Coint 5-19-14 Noise.png