2016/11/29 (Tuesday)
| Setup: DIB1/3/4 → 3.2 MHz filters → cables1/2/3 → DCRC55(1)/33(2)/50(3) | |
| 0830 | Main bath = 31.3% |
| 0900 | Finish IbIs on DCRC1pA |
| DCRC1 pA IbIs curve | DCRC1 pA prefactor |
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| Superconducting and transition/normal portions have been shifted based on extrapolated normal portion. Vertical axis is V, horizontal is μA | dP/dI prefactor calculated from the IbIs curve |
Both the above plots look quite reasonable.
| DCRC1 pA TES power in transition |
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| TES power as calculated from Ib and Is comparison using standard and adjusted calibration factors |
The above plot shows the TES power calculated using the standard assumption for the shunt resistance and for the feedback resistance and gain factors to calculate I_s from the output voltage. It also shows the result after an ad hoc adjustment to the gain to make the power flat with bias, as it should be. If any part of R_feedback*Loop_gain*DCRC_fixed_gain*Driver_gain is overestimated by 1.3, or if either the output voltage or QET bias are off by a constant factor, the power appears to be constant over the transition region.
| DCRC1 pA IbIs curve comparison |
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| Curves have been shifted so that 300 μA points are on the horizontal axis |
The above plot overlays previous mini-IbIs points with today's IbIs curve (solid). Three of the previous measurements line up perfectly with today's curve but on two days the operating points fell below the present curve. As noted before, the lower points imply higher TES bias power, implying lower parasitic power (i.e. the circuit must provide more power than usual to keep the TES in transition). This is an odd situation - the outlier cases seem to be periods of lower parasitic power.
| 0910 | Tower/MC/Coldplate = 33.3/34.7/234 mK, Still = 1.33 K / 110 μbar, G1/G2 = 192/204 mbar, 1K Pot = 1.70 K / 28 mbar. MB = 30.4%. Boil off rate: close to slow mode. |
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| 0920 | Start LHe transfer (30.4%) |
| 0955 | Finish LHe transfer (91.1%) |
| 1015 | Release pressure from MB. |
| 1050 | Re release pressure from MB. |
| 1125 | Finish IbIs on DCRC1pB. But it looks weird. |
| DCRC1 pB IbIs curve |
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| Raw curve. The red indicates where no pulses are seen, presumably superconducting Vertical axis is V, horizontal is μA |
There seem to be SQUID phase jumps through the transition and normal regions. Can this be avoided?
| 1155 | Try adjusting SQUID on DCRC1 pB. Used 50mVpp 200 Hz test signal. With Driver Gain = 1, modulation depth was 0.0096 V at previous SQUID bias of -81.9. Adjust to SQUID bias of -70.5 which give modulation depth around 0.014. Set lockpoint to -2.4. |
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| 1310 | Finish second IbIs with DCRC1pB. It looks no better: |
| DCRC1 pB IbIs curve |
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| Upper is old data, lower is new data. Raw curve. The red indicates where no pulses are seen, presumably superconducting Vertical axis is V, horizontal is μA |
There are some ugly pulses now too, should probably go back to the old SQUID settings.
| 1355 | Finish IbIs for DCRC1pC |
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| 1428 | Finish IbIs for DCRC1pD |
| 1546 | Finish IbIs for DCRC2pB & DCRC2pC |
| 1555 | Restore all channels to standard QET biases and driver gains (x8/x3/x8), and unrail channels. |
| 1650 | Fill LN2 cold trap full. |
| 2030 | Prepare to take some runs to test the retriggering issue, first remove pileup cut and re-enable triggering on DCRC1 |
| 2035 | Tweak channels to be in transition and have offsets near -1V. Changed QET bias very slightly on DCRC1 PhC and DCRC3 PhC (I think?) to be surely out of oscillation territory, reset all offsets to be near -1V again |
| 2046 | take short series 07161129_2046 with all triggers on and DCRC1 enabled for triggering |
| 2058 | take short series 07161129_2058 with only DCRC3 triggers on and DCRC1 enabled for triggering (should be moot) |
| 2112 | take short series 07161129_2112 with all triggers on and DCRC1 disabled for triggering |
| 2123 | take short series 07161129_2123 with only DCRC3 triggers on and DCRC1 disabled for triggering (should be moot) |
| 2133 | restore pileup cut to 150us and enable DCRC1 triggering by recompiling triggerfe2.exe with a code change |
| 2138 | Start sequence of 10 1-hour series of 0V self-triggered data with Frontend Gain = 5/2/5, OG = 8/3/8, with 1000 beginning randoms, no flashing, trigger on all side-1 channels (DCRC1 PhA,B,C; DCRC2 PhC; DCRC3 PhC,D) all triggers at 70 ADC samples |
| 2155 | woops, the above actually didn't have DCRC3 PhC triggering, so I stopped it, put this trigger on and restarted it quickly, nothing else changed |