2017/12/09 (Saturday)
| Setup: DIB1/3/4 → SL 27/19/20 → 3.2 MHz filters → cables 2,1,3 → HV board inputs 1,3,2 → HV board outputs 1,2 → DCRC55(1)/50(3). DCRC4 → HV power supply. PuBe source present. | |
| 1035 | Tower/MC/Coldplate = 21.5/24.7/151 mK, Still = 1.3 K / 0.100 mbar, G1/G2 = 247/224 mbar, 1K Pot = 1.63 K / 28 mbar, MB = 63.9% |
| 1035 | Dial HV up to 70 V with 15% 5-minute prebias, using changeHV_0_70_preBias15_5.msl |
| 1040 | Fill LN2 cold trap bath. |
| 1046 | Remove PuBe source from lab and move it to storage container in PAN 443 |
| 1110 | HV = 69.83 V, V_leak = 2.90 mV |
| 1115 | Adjust driver offset on DCRC3pB. Note: 0.1 change in Driver Offset = -0.4 V change in baseline = -2500 ADC change in baseline. Other channels look good. |
| 1120 | Estimate event rate from random traces. Set PhononWaveformLength on DCRC1 to 131072 which is 52.4288 ms and counted visible pulses in 75 pA traces. Counted 120 pulses in 3.9322 seconds, so event rate is around 30.5 ± 2.8 Hz. |
| 1123 | Start 93-minute background data series at HV = 70V, Driver Gains = 2x, QET biases = 480/360/440/480/380/490 uA, Front-End Gains = 10/5 on DCRC1/3, 1000 initial randoms, trigger on DCRC3pD (Side1pF) threshold = 14 |
| 1125 | HV = 69.83 V, V_leak = 2.76 mV |
| 1133 | DCRC3pB is railed low, try reducing D.O. from 0.1 to -0.2. Looks like it worked. |
| 1142 | DCRC3pB is railed low, try reducing D.O. from -0.2 to -0.5. Looks like it worked again. But there will be a few chunks in this data with no PA. |
| 1215 | DCRC3pB is railed low, try reducing D.O. from -0.5 to -0.8. Looks like it worked again. But I didn't catch it very early. Dumps 29-51 are all railed low. (A little later tweaked it down to -0.9.) |
| 1230 | HV = 69.83 V, V_leak = 2.60 mV |
| 1250 | DCRC3pB is not railed but it has drifted rather high. Try raising D.O. from -0.9 to -0.7. Looks like it worked. |
| 1256 | Stop data series |
| 1300 | Dial HV from 70 V down to 0 V using changeHV_70_0.msl |
| 1304 | Bring PuBe source back into lab and place behind shield |
| 1305 | Flash detector (LEDs on DCRC1&3) for 30s. |
| 1910 | Let's take some trigger test data. When we tried triggering on DCRC1pB, there seemed to be a trigger window: both an upper and a lower limit. But Anthony checked the code version we're using and there doesn't seem to be any issue (although he had set an upper limit on another version). We'll try triggering on each individual channel on the two DCRCs. |
| 1915 | Start 15-minute PuBe data series at HV = 0V, Driver Gains = 2x, QET biases = 480/360/440/480/380/490 uA, Front-End Gains = 10/5 on DCRC1/3, 1000 initial randoms, trigger on DCRC1pA threshold = 16 |
| 1931 | Start 15-minute PuBe data series at HV = 0V, Driver Gains = 2x, QET biases = 480/360/440/480/380/490 uA, Front-End Gains = 10/5 on DCRC1/3, 1000 initial randoms, trigger on DCRC1pB threshold = 16 |
| 1946 | Start 15-minute PuBe data series at HV = 0V, Driver Gains = 2x, QET biases = 480/360/440/480/380/490 uA, Front-End Gains = 10/5 on DCRC1/3, 1000 initial randoms, trigger on DCRC1pC threshold = 16 |
| 2001 | Start 15-minute PuBe data series at HV = 0V, Driver Gains = 2x, QET biases = 480/360/440/480/380/490 uA, Front-End Gains = 10/5 on DCRC1/3, 1000 initial randoms, trigger on DCRC3pB threshold = 16 |
| 2017 | Start 15-minute PuBe data series at HV = 0V, Driver Gains = 2x, QET biases = 480/360/440/480/380/490 uA, Front-End Gains = 10/5 on DCRC1/3, 1000 initial randoms, trigger on DCRC3pC threshold = 16 |
| this data is weird, looks like it's triggering at random… | |
| 2036 | Start 15-minute PuBe data series at HV = 0V, Driver Gains = 2x, QET biases = 480/360/440/480/380/490 uA, Front-End Gains = 10/5 on DCRC1/3, 1000 initial randoms, trigger on DCRC3pD threshold = 16 |
| That series looked normal. Let's try triggering on DCRC3pC again, with a higher threshold | |
| 2052 | Start 19-minute PuBe data series at HV = 0V, Driver Gains = 2x, QET biases = 480/360/440/480/380/490 uA, Front-End Gains = 10/5 on DCRC1/3, 1000 initial randoms, trigger on DCRC3pC threshold = 40 |
| 2056 | OK, this one's triggering normally. Try reducing threshold back down to 16. |
| 2101 | Huh, it's triggering randomly again. Strange because DCRC3pC baseline doesn't look noisier than any other. Raise threshold to 32. Looks like it's triggering on pulses again. |
| Results of these triggering tests are unclear. Didn't see the clear evidence of a high-end trigger threshold that we did before when we tried triggering on DCRC1pB versus DCRC3pD. But previously we ran at 70 V, not 0 V, so it was easier to see the high-end threshold show up around 100 keV. Without the x24 Luke gain, in this data it would show up at 2.4 MeV where the spectrum is already very small. So we should redo these tests at 70V. |