2011/05/01
| 0015 | Stop taking data. |
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| Flash detector overnight. | |
| Fill N2 cold trap full. | |
| 1710 | Fill N2 cold trap full. |
| 1735 | Stop flashing detector. |
| 1750 | Start LHe transfer. |
| 1830 | Stop LHe transfer. |
Neutralisation
| 2300 | Look at data series 07110428_1946. Histogram of Qsum shown in Figure 1 and scatter plot of Qsum as a function of time in Figure 2. |
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| Figure 1: Qsum after low energy, Qpart & chi2 cuts. |
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| Figure 2: Qsum after low energy, Qpart & chi2 cuts as a function of time. |
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| The 60 keV line is not visible in Figure 2. | |
| The threshold of 40 ADC bins (approximately 2.6 mV) might be too high and cuts out a number of 60 keV events. The relatively small number of events in the 60 keV peak in Figure 1 seems to indicate this. However, charge signals from 60 keV events should be around 3 mV in amplitude, and should satisfy the trigger threshold. Perhaps neutralisation degrades extremely quickly under bias, and the signals drop below threshold. | |
| We could try a Ba-133 run to see if we get any joy. |