2021/03/10 (Wednesday)
- Lab in-person: Derek
- Virtual partner: Matt
| Status | Run 74 in progress. Just recooled after a partial warmup to recheck continuity to Side2 (continuity verified). |
|---|---|
| Setup: DIB1/2+acc → SL 41/43 → 3.2 MHz filters → cables 2/3 → nothing/nothing → DCRC50(3)/ |
|
| 1327 | MB = 62.1% |
| 1400 | Tower = 90.7 mK, Still = 0.130 mbar, G1/G2 = 400/380 mbar. Tower temperature pretty stable (and this is I think the lowest it's been) |
| 1408 | Derek enters lab |
| 1411 | Tower/MC/Coldplate = 90.7/38.8/184 mK, Still = 1.42 K / 0.130 mbar / 0 mW, G1/G2 = 400/381 mbar, 1K Pot = 1.69 K / 45±2 mbar. |
| 1415 | Check noise in the two DCRC3 channels (DCRC1 is not connected). DCRC3qI/qO = 1.12/1.05 e-6 @ 10 kHz. These are quite low compared to anything we've seen so far. |
| 1416 | Fill LN2 cold trap bath. |
| Troubleshooting the Side2 connection. Currently Cable 3 is connected to the breakout box so we can connect to Side2 via QET A Ret #1. | |
| 1435 | First look at the channels and apply a 5V bias on the DCRCs (note - only biasing 2 channels, other two are floating). We see more pulses. Turn bias back to 0V. Then connect Side2 to the DCRC3 Dsub shell. We see an extra high-frequency noise component around 60 kHz - so it does do something. It goes away when we unplug from the breakout box. Now try applying +5V again. Hard to see any difference from the pulse viewer, we probably have to take data and analyze it to see if there is a difference. |
| 1500 | Tried applying bias to Side2 with the Kepco 0-40V power supply: + connected to the DCRC3 Dsub shell, - connected to Side2. We aren't seeing the terrible noise that we saw when we tried this through the diverter board. Increase bias from 0V to 5V. It looks like there are indeed more triggers at 5V than at 0V. So maybe it is working. We see some wiggly noise when we are ramping the voltage. |
| 1505 | Plug DCRC55(1) into the mini-BOB and power it up. This way we can take data from both DCRCs (with DCRC1 just noise pulses) and we can process it with the standard processing, hopefully. |
| 1510 | Check the noise in the channels - looks a bit worse in DCRC3, some high-frequency junk. Also noise in DCRC1 is sorta ugly, not certain it will process properly. (Could consider railing the DCRC1 channels maybe.) |
| 1520 | At 10 kHz noise in DCRC3qI/qO/DCRC1qI/qO = 10/7.9/2.8/3.5. |
| 1615 | Tried a few things to reduce the noise. The high frequency peaks show up when the Side2 ground cable is connected. Derek tried improving the connections a bit, it may have helped a little. Try to find the lowest trigger thresholds, settle on DCRC3qI/qO = 250/200. |
| 1619 | Start 31min series of +7V data (bias applied after 1 min), with Cable 3(DCRC1) plugged into breakout box and ground cable from Side2 to DCRC3 Dsub, with 1000 beginning randoms, trigger threshold 250/200 on DCRC3qI/qO, no in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Use sequence r74_takeandflash_dcrcbias.msl |
| It's triggering a lot but I'm seeing some pulses in the correct place so I guess it's OK. | |
| This data didn't write to disk. Why? |