2018/03/06 (Tuesday)
| Status: First LHe transfer yesterday. Baking detector with all 4 LEDs overnight, at 4K. DIB1/2 connected to DCRC50(3)/DCRC55(1). | |
| 0856 | Fill LN2 cold trap bath |
| 1015 | MC(Cernox) = 4.34 K, Sorb = 5.9 K, 1K Pot = 4.68 K, Turbo (on IVC) = 14 nbar, G1 (fridge) = 539 mbar, Main bath = 44.7% |
| 1020 | Turn off all 4 LEDs at the ODB. |
| 1030 | Set a +5V bias on all 4 channels. Look for reasonable threshold settings. DCRC3qI (DIB1qI) is clearly the noisiest channel, needs a much higher threshold. |
| 1040 | Let's take some data here at 4K. We can compare noise to what we get at base temperature, see if there's a difference. Do we even have to cool to base? |
| 1042 | Start 30min series of 5V data (DCRC bias), with 1000 beginning randoms, and a 700/100/150/150 bin threshold trigger on DIB1qI/qO/DIB2qI/qO, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). |
| 1105 | Pump out line leading to 1K Pot, then open 1K Pot speedivalve. (Note that 1K Pot was evacuated before LHe transfer and needle valve was closed.) About 0.23 bar in 1K Pot. Pot temperature dips to 3.6 K when valve opened, then rises again. Pump out for a few seconds with scroll pump, then switch to 4He pump. Open the two valves to connect 4He exhaust to recovery. |
| 1115 | Set detector bias to 0 V after ending data series |
| 1115 | 1K Pot = 4.70 K / 1.9 mbar Open 1K Pot Needle Valve to ~10 degrees. 1K Pot → 3.3 K / 40 mbar. After a few minutes, pressure falls to 2.4 mbar. |
| 1120 | Open Needle Valve a few more degrees. 1K Pot → 3.3 K / 3.0 mbar Open Needle Valve a few more degrees. 1K Pot → 3.2 K / 4.0 mbar Open Needle Valve a few more degrees. 1K Pot → 3.10K / 5.0 mbar Open Needle Valve a few more degrees. 1K Pot → 2.9 K / 6.0 mbar |
| 1125 | Open Needle Valve a few more degrees. 1K Pot → 2.6 K / 10 mbar, some oscillations |
| 1130 | Tower temp and Fridge pressure falling. Tower = 4.20 K, G1(fridge) = 490 mbar |
| 1130 | Open Needle Valve a few more degrees. 1K Pot → 2.4 K / 16 mbar Open Needle Valve a few more degrees. 1K Pot → 2.1 K / 22 mbar |
| 1135 | Tower temp falling faster, Tower = 3.76 K and falling. (Tower temperature drop coincides with flat period in 1KPot pressure, oscillations gone) |
| 1135 | Open Needle Valve a few more degrees. 1K Pot → 1.9 K / 26 mbar Open Needle Valve a few more degrees. 1K Pot → 1.85 K / 36 mbar |
| 1140 | Open Needle Valve a few more degrees. 1K Pot → 1.8 K / 40 mbar |
| 1145 | Tower = 3.67 K (falling), 1K Pot = 1.81 K, Fridge(G1) = 400 mbar (falling) |
| 1210 | Tower = 3.60 K (flat), 1K Pot = 1.77 K, Fridge(G1) = 341 mbar (rising a little) |
| 1210 | 1K Pot pressure has fallen to 15 mbar Open Needle Valve a few more degrees. 1K Pot → 1.77 K / 26 mbar Open Needle Valve a few more degrees. 1K Pot → 1.79 K / 36 mbar |
| 1235 | Had lunch, and again pot pressure is falling, Pot & Tower temps & fridge pressure rising |
| 1235 | Tower = 3.62 K, 1K Pot = 2.2 K, Fridge(G1) = 357 mbar Open Needle Valve several more degrees. 1K Pot → 1.8 K / 45 mbar |
| 1245 | 1K Pot pressure is falling again, down to 30 mbar Open Needle Valve a few more degrees. 1K Pot → 1.79 K / 40 mbar |
| 1305 | 1K Pot pressure is falling again, down to 22 mbar Open Needle Valve a few more degrees. 1K Pot → 1.78 K / 34 mbar Open Needle Valve a few more degrees. 1K Pot → 1.79 K / 38 mbar |
| 1315 | Tower = 3.52 K, 1K Pot = 2.8 K, Fridge(G1) = 271 mbar |
| 1325 | 1K Pot pressure is falling again, down to 24 mbar Open Needle Valve a few more degrees. 1K Pot → 1.78 K / 34 mbar Open Needle Valve a few more degrees. 1K Pot → 1.81 K / 55 mbar |
| 1400 | 1K Pot pressure is falling again, down to 22 mbar Open Needle Valve a few more degrees. 1K Pot → 1.80 K / 45 mbar |
| 1445 | 1K Pot pressure is falling again, down to 20 mbar Open Needle Valve a few more degrees. 1K Pot → 1.79 K / 40 mbar |
| 1445 | Tower = 3.47 K, 1K Pot = 1.8 K, Fridge(G1) = 237 mbar |
| 1505 | 1K Pot pressure is falling again, down to 24 mbar Open Needle Valve a few more degrees. 1K Pot → 1.78 K / 34 mbar Open Needle Valve several more degrees. 1K Pot → 1.83 K / 120 mbar |
| 1507 | Start LHe transfer (MB = 37.5%) |
| 1510 | 1K Pot pressure spiked off scale, but it's coming down again, currently 40 mbar |
| 1540 | 1K Pot pressure is falling again, down to 18 mbar Open Needle Valve a few more degrees. 1K Pot → 1.78 K / 45 mbar |
| 1605 | End LHe transfer (MB = 88.2%) |
| 1650 | I opened the 1K Pot Needle valve wider several more times, got tired of writing down the numbers every time, same pattern of behavior, keeps running dry. Cooldown going slowly. |
| 1655 | Tower = 3.42 K, 1K Pot = 1.75 K, Fridge(G1) = 220 mbar |
| 1656 | Fill LN2 cold trap full. |