2018/07/23 (Monday)

Previous Day

	overnight: Tower temp, circulation pressures, 1K Pot mostly flat
0805	Tower = 94 K, G1/G2 = 457/417 mbar, Still = 0.055 mbar / 0.1 mW, 1K Pot = 1.45 K / 4.0 mbar.
0810	Open 1K Pot needle valve 140→150°, to see what happens. Tower falls a little, Condenser rises a little.
0815	Turn off MIDAS DAQ programs, ground HV supply, power down all three DCRCs. (this causes a small spike in temperature)
0815	1K Pot = 1.61 K / 20 mbar
0820	Tower = 86 mK, Condenser = 483 mbar. No improvement. We should warm up again and see if there's as much pressure in the IVC as before.
0820	Turbo on IVC = 2.5 nbar. Close valve to turbo pump. With pump valved out, IVC = 25 nbar.
0923	Fill LN2 cold trap full.
	filling trap caused fall in Condenser 480-455 mbar, rise in Tower temperature 89→103 mK
1050	Turn Still heater on to 5 mW, Still→0.110 mbar. Tower falls to 90 mK, at least initially. Condenser pressure rises above 500 mbar.
1235	Tower temperature started increasing again, now Tower = 120 mK, Condenser = 711 mbar.
1240	Suspend circulation: close V6, open V9
1310	Tower = 707 mK, Condenser = 155 mbar, IVC = 25 nbar Close 1K pot needle valve and 1K pot speedivalve. Set MC/Still heaters = 20/20 mW.
1410	Tower = 3.4 K, Condenser = 328 mbar, IVC = 25 nbar
1450	Tower/1K Pot/Sorb = 6.57/4.32/5.5 K, Condenser = 328 mbar, IVC = 34 nbar. Condenser rising, Tower rising slowly
1515	Tower/1K Pot/Sorb = 7.21/6.35/8.1 K, Condenser = 560 mbar, IVC = 46 nbar. Condenser and Tower look flattish now. This is warmer than we got the Tower to last time, so I guess that means less helium in the IVC but it's still apparently present because the Tower temperature is hanging. And the IVC pressure is not as high as last time.
1555	Tower/1K Pot/Sorb = 7.26/6.54/8.4 K, Condenser = 580 mbar, IVC = 46 nbar. All temperatures and Condenser pressure flat.
	let's try turning off heaters and see if this makes Pot and Sorb get warmer, like it did last time
1600	Turn off MC and Still heaters. Tower temperature goes down - also Pot and Sorb go down. (Main Bath higher this time, 62%, maybe that's the difference). IVC falls to 34 nbar
1650	Tower/1K Pot/Sorb = 5.64/6.55/8.5 K, Condenser = 575 mbar, IVC = 34 nbar. Tower is not settling toward 4.4 K as quickly as on Wednesday
1650	Turn on MC and Still heaters again to 20/20 mW Tower bounces right back to 7.23 K, pot/sorb don't change much. IVC = 46 nbar
1745	Open Turbo valve to pump on IVC. Tower temperature starts increasing immediately.
1750	Fill LN2 cold trap bath
1755	Tower = 7.6 K
1835	Tower = 9.9 K
1900	Tower = 11.7 K, Sorb 11 K, 1K Pot > 7K
1905	Reduce heaters on MC/Still 20/20→3/3 mW
1940	Tower = 11.8 K and flat or falling slowly
2140	Tower = 11.75 K

Next Day