Ce-137 Comparison to background

SiPM 2 and SiPM 4 were placed in their delrin holders on either side of plastic the scintillator and placed in the darkroom. Each event was self-triggered when both SiPMs were above a trigger threshold of 8320. When a Ce-137 source was present, it was placed 10 cm from the plastic.

Table 1: Data files used.
Run	Source	Scintillator	Fiber	Grease	Number of events	Data file
1	background	1-66-?	none	none	10k	130722_sipm2+4_background_8320threshold.dat
2	Ce-137	1-66-?	none	none	10k	130723_sipm2+4_cs-137_8320threshold.dat
3	background	1-74-1	yes	yes	10k	130722_sipm3+4_background_8320threshold_short.dat
4	Ce-137	1-74-1	yes	yes	10k	130724_sipm2+4_cs-136_8320threshold_WLSfiber.dat
5	background	1-74-1	yes	none	10k	130725_sipm2+4_background_8320threshold_WLSfiber.dat
6	Ce-137	1-74-1	yes	none	10k	130724_sipm2+4_cs-136_8320threshold_WLSfiber-2.dat

No Fiber

Background

Figure 1: Area under the pulse for SiPM 2 only, SiPM 4 only, and SiPM 2 and 4 combined.

The histograms above exclude pulses with a baseline standard deviation greater than 7 or if secondary pulses are present.

Ce-137

Figure 2: Area under the pulse for SiPM 2 only, SiPM 4 only, and SiPM 2 and SiPM 4 combined.

The above histograms exclude pulses with a baseline standard deviation greater than 7 or if secondary pulses are present.

Figure 3: Comparison of Cesium-137 and background spectra.

With wavelength shifting fiber and optical coupling grease

Background

Background data were taken two days before the Ce-137 run. Background data previously shown with barium.

Figure 4: Area under the pulse for SiPM 2 only, SiPM 4 only, and SiPM 2 and SiPM 3 combined.

The above histograms exclude pulses with a baseline standard deviation greater than 7 or with secondary pulses present.

Ce-137

Figure 5: Area under the pulse for SiPM 2 only, SiPM 4 only, and SiPM 2 and SiPM 4 combined.

The histograms in Figure 5 exclude pulses with a baseline standard deviation greater than 7 or with secondary pulses present.

Figure 6: Comparison of background and source spectra.

With wavelength shifting fiber and no optical coupling grease

Background

Figure 7: Area under the pulse for SiPM 2 only, SiPM 4 only, and SiPM 2 and SiPM 3 combined.

The above histograms exclude pulses with a baseline standard deviation greater than 7 or with secondary pulses present.

Ce-137

Figure 8: Area under the pulse for SiPM 2 only, SiPM 4 only, and SiPM 2 and SiPM 4 combined.

The histograms in Figure 8 exclude pulses with a baseline standard deviation greater than 7 or with secondary pulses present.

Figure 9: Comparison of background and source spectra.

Scintillator Comparison

Figure 10: Comparison of Ce-137 Spectra for each scintillator set-up.