10-31-08 GEM HRRL Photon Runs

The Goal today is to observe position dependence of photons on the GEM detector

A1 -> 13 A2 -> 11 A3 -> Trig A4 -> 2 A6 -> 16 A7 -> 8 A8 -> 5 A9 -> NaI -> B9

B1 -> ADC1A

Run 0

GEM Backgrnd.mpa

GEM HV : VDrif = 3850, VGem = 3550

HRRL : E = 14 MeV, I =0

5 minutes long

Run 1

Run1.mpa

GEM HV : VDrif = 3850, VGem = 3550

HRRL : E = 14 MeV, I =20mA

ADC 1D has clear second peak at channel 150 but ADC1 does not. Lets Observe ADC 1D as a function of position. This corresponds to GEM output strip 13.

5 minutes long

Run 2

Run2.mpa

GEM HV : VDrif = 3550, VGem = 3550

HRRL : E = 14 MeV, I =20mA

5 minutes long

I see a second peak on ADC1D but it is at channels 100 and not 150.

Run 3

Run3.mpa

GEM HV : VDrif = 3550, VGem = 3550

HRRL : E = 14 MeV, I =20mA

3 minutes long

Unplug NaI and peak resumes near 150 channels

Run 4

Run4.mpa

GEM HV : VDrif = 3850, VGem = 3550

HRRL : E = 14 MeV, I =20mA

Now turn the detector on with the beam current on and I see a peak around 150 channels again.

3 minutes long. OOOPPPs left DAQ running while we moved the detector. Only look at first 3 minutes.

Pin 13 was located 63 cm from the mounting bracket horizontal cross bar.

Run 5

Run5.mpa

GEM HV : VDrif = 3850, VGem = 3550

HRRL : E = 14 MeV, I =20mA

Now move the detector away from the photons.

Pin 13 is a distance of 22 cm from the mounting bar moved 41 cm from its original location at 63 cm

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