2016/10/27 (Thursday)
| The strong Y source was left out overnight. Some tests with the NaI detector were performed yesterday afternoon but I have no way of knowing what the status is currently. So I'll put the source away. | |
| 0845 | Put Y source back in safe. |
| Setup: DIB1/3/4 → 3.2 MHz filters → cables 1,2,3 → HV board inputs 1,3,2 → HV board outputs 1,2 → DCRC55(1)/50(3) | |
| 0845 | Tower/MC/Coldplate = 35.1/37.7/219 mK, Still = 1.15 K / 65 μbar, G1/G2 = 95/85 mbar, 1K Pot = 1.45 K / 1.9 mbar. MB = 73.5%. At around 6:15 the 1K Pot had fallen out of its oscillatory behavior. It probably came close to failing. Boiloff rate: good, a little better maybe than slow-mode. Pressure was released from MB at 23 and 77 minutes after yesterday's fill. |
| 0855 | Tweak 1K pot needle valve open a few more degrees |
| 0900 | Fill LN2 cold trap bath. |
| 1000 | Tower = 33.0 mK, Still = 90 μbar, G1/G2 = 120/110 mbar, 1K Pot = 1.59 K / 6.5 mbar. Mostly settled after the 1K Pot tweak. Might need another. |
| 1025 | Perform mini-IbIs to calculate TES resistances in current setup. For HV2pC the resulting Rnormal is very different from what we previously measured. |
| 1200 | Take more IbIs data for HV2pC. It's strange and not consistent with the last test. There may be SQUID phase shifts at high biases in the normal regime, but this would be strange. Should check the SQUID. |
| Channel | TES | QET bias [μA] | Rnormal [mΩ] | Rbiased [mΩ] | Rbiased/Rnormal |
|---|---|---|---|---|---|
| HV 1 pA | 4 | 179 | 91 | 44.1 | 48.4 % |
| HV 1 pB | 3 | 185 | 92.1 | 46.8 | 50.9 % |
| HV 1 pC | 2 | 184 | 67.8 | 37.8 | 55.8 % |
| HV 2 pB | 5 | 195 | 82.8 | 70.6 | 85.4 % |
| HV 2 pC | 1 | 170 | 236.4(??) | 134.9(??) | 57.1 % |
| HV 2 pD | 0 | 208 | 77.3 | 47.4 | 61.3 % |
| 1235 | Place 88Y source at fridge for NaI test. Source is kept inside its lead container. |
|---|---|
| 1246 | Take test series of data triggering on DCRC1pB, recording data from DCRC1,3,4. DCRC4 is receiving external triggers from the NaI detector. |
| 1251 | Take test series with DCRC4 as the trigger. A TTL trigger output from the NaI detector is fed into an LED line of DCRCX(4) and the LED is connected to pA. Triggering on DCRC4 with threshold 100. The NaI is set to trigger on a window around the 1.836 MeV Y peak. The detector is positioned directly across from the source, so the deflection angle is near zero. |
| 1412 | Revert DAQ to normal HV data taking mode. Look at HV2 pC modulation curve to see if there's anything strange there. Very noisy modulation curve. Increasing the SQUID Bias helps somewhat, but overall it's just a very distorted looking modulation curve. Redo mini IbIs for that channel. |
| Old SQUID Bias/Lockpoint = -48 uA / -0.90 mV | |
| New SQUID Bias/Lockpoint = -60.2 uA / -1.3 mV | |
| 1425 | Mini IbIs looks much more reasonable now. Although Rnormal is still strange: |
| Channel | TES | QET bias [μA] | Rnormal [mΩ] | Rbiased [mΩ] | Rbiased/Rnormal |
|---|---|---|---|---|---|
| HV 2 pC | 1 | 170 | 151.8(??) | 50.2 | 33.1 % |
| 1530 | After checking modulation curve for HV1 pB, the modulation curve looks fine. |
|---|---|
| 1540 | Flash for 30s, then cooldown for 10 minutes. Tower temp reaches 525mK, but both the rise and fall were very quick. |
| 1555 | Start one accidental series |
| 1600 | Apply +15V HV to detector, wait a minute, then dial back to 10 V. Measure leakage, Vtest = 1.5 mV. So Vcrystal = 9.34 V |
| 1602 | Start data series at 10.0 V HV, with standard 3.2768 ms trace lengths, all randoms. But we'd meant to do 20 ms traces, so this was an accident. |
| 1622 | Stop data and dial HV to zero, short the HV input. |
| 1630 | Flash detector again for 30s |
| 1705 | Tower = 33.7 mK, Still = 85 μbar, G1/G2 = 115/105 mbar, 1K Pot = 1.57 K / 5.5 mbar. MB = 62.4%. Tweak 1K Pot needle valve open a few degrees |