2018/09/19 (Wednesday)
| Setup: DIB1/3/4 → 3.2 MHz filters 2/3/1 → cable 3/1/2 → gender changer 3/?/2 → HVConn 1/3/2 → HV 1/2 → DCRC55(1)/DCRC50(3) 1.1kV → NaI B/C → Ortec 452(gain=5, shaping = 6 us, output=10V) / Ortec 575A(gain=10, shaping = 3us) → x10/x10 attenuator → DCRCX(4) DCRC33(2) → kepco 1kV power supply → HV input |
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| status: | Took bkg data overnight at 50V. Long dataset without flashing. |
| 0940 | Tower/MC/Coldplate = 29.7/29.1/185 mK, Still = 1.0 mW / 1.4±0.1 K / 0.080 mbar, G1/G2 = 126/118 mbar, 1K Pot = 1.59 K / 17 mbar, Turbo on IVC = 0.86 nbar, MB = 69.6% |
| 0945 | Fill LN2 cold trap bath. |
| 0946 | We've been biased for a while, so the resolution is probably garbage. Let's try to increase the bias for a little bit, then bring it back down (no grounding or flashing) and see if that improves the noise. |
| 0947 | Start 1 hr, 50 V, test dataset split into 10 min subruns, with CDMS and NaI detectors running and DCRC2 as HV controller. Using sequence timed_subrun.msl CDMS detector: Driver Gains = 2x, QET biases = (280/260/305)/(140/280/295) uA, Front-End Gains = (10/10/10)/(10/15/10) NaI detector: 1.1kV → NaI B/C → Ortec 452(gain=5, shaping = 6 us, output=10V, Pos) / Ortec 575A(gain=10, shaping = 3us, Pos) → x10/x10 attenuator → DCRC4PB/PA, Driver Gains = 1/1, PhononWaveFormLength = 1024 (512 samples), PhononPrepulseSamples = 64 (64 samples) 1000 BOR randoms, trigger on DCRC3pB/C/D threshold = 7/10/9 |
| 1012 | Increase bias to 60V by manually changing DCRC2QI down to 4.75 V in the ODB. |
| 1017 | Just before the randoms in 07180919_1018, reduce bias to 50V by manually changing DCRC2QI up to 5.869 V in the ODB. |
| 1051 | Set HV = 0V using change_HV_50_to_0_DCRC2.msl. Flash detector for 30s. |
| 1211 | Set up Agilent 81101A Pulse Generator to output 1 us long pulses with the leading/trailing edge% = 5/90 at a rate of 20Hz. Split and input the signal into both NaI amplifiers (and the oscilloscope). |
| 1219 | Start NaI amplifier test dataset with NaI detector: Agilent 81101A → Ortec 452(gain=5, shaping = 6 us, output=10V, Neg) / Ortec 575A(gain=10, shaping = 3us, Neg) → x10/x10 attenuator → DCRC4PB/PA, Driver Gains = 1/1, PhononWaveFormLength = 1024 (512 samples), PhononPrepulseSamples = 64 (64 samples) 0 BOR randoms, trigger on DCRC4pA threshold = 5 Vary Pulse Amplitude in the following steps for ~1 min each : (0, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10) V |
| 1241 | May want to redo the above test with a threshold of 10, we were getting a lot of noise traces throughout. |
| 1248 | Start NaI amplifier test dataset with NaI detector: Agilent 81101A → Ortec 452(gain=5, shaping = 6 us, output=10V, Neg) / Ortec 575A(gain=10, shaping = 3us, Neg) → x10/x10 attenuator → DCRC4PB/PA, Driver Gains = 1/1, PhononWaveFormLength = 1024 (512 samples), PhononPrepulseSamples = 64 (64 samples) 1000 BOR randoms, trigger on DCRC4pA threshold = 10 Vary Pulse Amplitude in the following steps for ~1 min each : (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10) V |
| 1320 | Restore standard NaI setup. |
| 1330 | Set HV = 80V using change_Hv_0_to_80_preBias_15_5_DCRC2.msl |
| 1339 | Start 2 hr, 80 V, dataset split into 10 min subruns, with CDMS and NaI detectors running and DCRC2 as HV controller. Using sequence timed_subrun.msl CDMS detector: Driver Gains = 2x, QET biases = (280/260/305)/(140/280/295) uA, Front-End Gains = (10/10/10)/(10/15/10) NaI detector: 1.1kV → NaI B/C → Ortec 452(gain=5, shaping = 6 us, output=10V, Pos) / Ortec 575A(gain=10, shaping = 3us, Pos) → x10/x10 attenuator → DCRC4PB/PA, Driver Gains = 1/1, PhononWaveFormLength = 1024 (512 samples), PhononPrepulseSamples = 64 (64 samples) 1000 BOR randoms, trigger on DCRC3pB/C/D threshold = 7/10/9 |
| 1544 | Turn down HV and flash for 30s |
| 1650 | The amplifier tests above were confusing because the digitized amplitudes only reached the signal level of ~1MeV, even though the injected pulse heights should have corresponded to much higher levels. Realized that I also had the input pulse signal connected to the oscilloscope and that was sinking a good part of the signal. Repeat with the pulse generator output split to the two amplifiers only. This gives pulses consistent with those obtained by feeding the signal into a single amplifier at a time. Also, adjusted the pulse shape to match NaI pulses better. |
| 1211 | Set up Agilent 81101A Pulse Generator to output 72 ns long pulses with the leading/trailing edge = 50/200 ns at a rate of 20Hz. Save these settings in register 5. Split and input the signal into both NaI amplifiers. |
| 1655 | Start NaI amplifier test dataset with NaI detector: Agilent 81101A → Ortec 452(gain=5, shaping = 6 us, output=10V, Neg) / Ortec 575A(gain=10, shaping = 3us, Neg) → x10/x10 attenuator → DCRC4PB/PA, Driver Gains = 1/1, PhononWaveFormLength = 1024 (512 samples), PhononPrepulseSamples = 64 (64 samples) 1000 BOR randoms, trigger on DCRC4pA threshold = 10 Vary Pulse Amplitude in the following steps for ~1 min each : (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10) V |
| 1700 | Fill LN2 cold trap full. |
| 1714 | Restore standard NaI setup. |