| | We've been flashing the detector (G110) overnight, with the Ba source taped to the Dewar 26“ down from the bottom of the dewar flange. MC has stayed at around 110 mK. G1/G2 pressures and MC temperature rose slowly to 140 mbar / 120 mK, then at around 7:50 they both fell off quickly to 90 mbar / 110 mK. |
| 0900 | MC/Tower = 111/391 mK, G1/G2 = 96/104 mbar. Still = 4 mW / 1.11 K / 0.19 mbar. 1K Pot = 1.70 K / 20 mbar. Cold plate = 9.18 kΩ / 321 mK. Main bath = 7.7%. |
| 0907 | Turn off DIB1/DCRC50 flashing. MC/Tower fall to 79/217 mK. |
| 0921 | Turn off DIB2/DCRC33 flashing. MC/Tower fall to 57/77 mK. |
| 0923 | Fill LN trap Dewar. |
| 0954 | MC/Tower = 56/75 mK, G1/G2 = 97/103 mbar. Still = 4 mW / 1.11 K / 0.19 mbar. 1K Pot = 1.70 K / 20 mbar. Cold plate = 9.48 kΩ / 307 mK. MC sensor = -36.14 kΩ. |
| 1005 | Commence LHe transfer (3.4%) |
| Cooling power test |
| time | MC heat | Still heat | MC temp | Tower temp |
| 1020 | 0 uW | 4 mW | 55 mK | 73 mK |
| 1056 | 200 uW | 15 mW | 148 mK | 155 mK |
| 1107 | 180 uW | 15 mW | 157 mK | 164 mK |
| 1116 | 160 uW | 15 mW | 144 mK | 152 mK |
| 1132 | 140 uW | 15 mW | 136 mK | 143 mK |
| 1150 | 120 uW | 15 mW | 128 mK | 137 mK |
| 1215 | 100 uW | 15 mW | 116 mK | 124 mK |
| 1235 | 80 uW | 15 mW | 113 mK | 122 mK |
| 1251 | 60 uW | 15 mW | 102 mK | 111 mK |
| 1302 | 40 uW | 15 mW | 92 mK | 103 mK |
| 1326 | 20 uW | 15 mW | 75 mK | 89 mK |
| 1344 | 0 uW | 15 mW | 56 mK | 74 mK |
Lock DIB1 SQUIDs using DCRC50, borrowed from DIB3 (since DCRC 31 is unusable):
| DIB1 DCRC50 | SQUID Bias [uA] | Lockpoint [mV] | Modulation Depth [Vpp] |
| A | -80.08 | -4.67 | .330 |
| B | -88.03 | -2.14 | .355 |
| C | -85.94 | -2.82 | .451 |
| D | -83.99 | -3.02 | .352 |
Found transition temperatures of DIB2 TESs by sending a triangle wave (10Vpp, 100 Hz) down the QET line and watching the patterns on all four QET signals as we applied heat to the MC to warm the crystal. We watched the patterns disappear as the TESs warmed past their transitions and reappear as they cooled again.
| Tc measurements for DIB2 (DCRC33); measured MC temp. / inferred Tower temp. |
| Channel | Temp. at which pattern disappears while heating | Temp. at which pattern appears while cooling |
| A | 91 mK / 102 mK | 86 mK / 98 mK |
| B | 99 mK / 109 mK | 96 mK / 107 mK |
| C | 87 mK / 99 mK | 82 mK / 95 mK |
| D | 100 mK / 110 mK | 97 mK / 108 mK |
We were unable to do this with DIB1 using DCRC50 because we couldn't manage to send a triangle wave down the QET lines.
Set approximate QET biases on DIB2 by watching for pulses - increase bias from zero until good phonon pulses are seen. (First pulses seen in PAN!)
| Approx. QET biases for DIB2 (DCRC33) |
| Channel | QET bias (μA) |
| A | -120 |
| B | +100 |
| C | -120 |
| D | -110 |
| NOTE that for channel B, positive bias was required to see upright pulses. |
Charge breakdown study: we intended to apply opposite and equal biases to the DIB1 (DCRC50) and DIB2 (DCRC33) charge channels and increase the bias while looking
at pulses on DIB2 for signs of breakdown. However at some point an interference pattern appeared in the DIB2 charge channels (and only noise in the phonon channels)
which suggested from past experience some interference between DCRCs/DIBs. So we were forced to remove DCRC50 and put a grounding plug on the DIB1 connector at the Ebox. This kept the Side 1 (DIB1)
charge channels grounded, so we could try changing the bias on Side 2 only. We did this and watched the pulses; when we started to see distorted pulses we designated that as the breakdown bias.
| Charge breakdown |
| Side 1 bias | Side 2 bias |
| 0 V | ≥ 9 V |
| 0 V | ≤ -4.5 V |
| 1700 | Leave IbIs program running overnight for DIB 2. |