2022/06/07 (Tuesday)
- Lab in-personnel: Matt, Giulia
| Status | Run 76 in progress |
|---|---|
| Setup | Cables 2/3/1 → diverter/nothing/nothing → Side2-readout HV CONN 1/3/2 → HV 1(L)/2(R) → DCRC50(3)/DCRC55(1), DCRC33(2)→HV control, NaI trigger signal → DCRCX(4) |
| 1135 | MC/Coldplate = 28.3/145 mK, Still = 1.09 K / 0.100 mbar / 0 mW, G1/G2 = 136/133 mbar, 1K Pot = 45° / 1.55 K / 8.5±0.5 mbar, MB = 33.0% |
| 1140 | Fill LN2 cold trap bath. |
| 1500 | Receive new LakeShore U09212 calibrated thermometer. Info here: thermometer |
| 1534 | Begin LHe tranfer @ MB = 27.5% |
| 1623 | End LHe tranfer @ MB = 95.6 % |
 | This image shows the main part of the lead shield, the SiHV detector, the NaI detector array, and the standard position of the PuBe source (which will be in the paraffin drum placed on the floor up against the shield). As can be seen the bottom NaI detectors are not shielded, and lines of site to the topmost NaI detectors don't pass through very much lead. |
 | Top view shows that the shield is plenty wide enough. We could move the source over a little in the opposite direction of the vertical NaI stack but it isn't really necessary. |
 | Back view |
 | If we raise the drum up 12 cm (approximately 3 2×4“ boards) we see that the bottom NaI detectors are now shielded with the full 12-inch width of lead. The top detectors are of course more exposed than before. |
 | Adding a 2×3 stack of lead bricks (2X4X8” each) seems to be enough to shield the top detectors. |
 | 3 inches from the edge of the main stack seems to be about the right place to optimize shielding the top detectors |
 | Back view |