PMT Spectra of Ce-137

PMT 14 was run with a bias voltage of -1100 V with scintillator 1-66-? and Ce-137 with a copper collimator attached to plastic in the darkroom. The connection to the DAQ board was modified with varying attenuators. Each event was self-triggered with a varying trigger threshold for a total of 100k events.

Figure 1: Standard Deviation of the baseline.

The red line at a standard deviation of 6 in Figure 1 is the highest baseline standard deviation allowed in the subsequent plots for the 10x attenuated Ce-137 run.

The red line in Figure 2 represents the saturation limit of 4500 channels for the pulse amplitude. This pulses used to make this histogram have a baseline standard deviation less than 6.

Figure 3: Pulse maximum amplitude and area

Both histograms in Figure 3 exclude pulses with an amplitude greater than 4500 channels or a baseline standard deviation greater than 6. the histogram of area under the pulse also excludes pulses with a secondary pulse before the main pulse.

Figure 4: Comparison to background.

Figure 5: Comparison to background (zoomed in).

The background data is explained in this post.