2016/12/16 (Friday)

Previous Day

	Setup: DIB1/3/4 → 3.2 MHz filters → cables 1,2,3 → HV board inputs 1,3,2 → HV board outputs 1,2 → DCRC55(1)/50(3)
	taking 100V data overnight
0411	Mostly noise pulses. Raise DCRC3pC trigger threshold from 12 to 15
0600	1K Pot pressure beginning to decrease, 1K Pot temp increasing, circ pressures increasing G1/G2 = 235/215, 1K Pot = 2.05 K / 13 mbar (monitoring remotely using Log options on the LabVIEW vi's)
	1K pot failed around 5:50 am, as predicted by estimating when the MB would hit 0% using the bath calculator At 5:50, 1K Pot temp rose 1.65→1.95 K, 1K Pot pressure fell from 16→14 mbar, Tower rose from 33→40 mK, G1/G2 began rising from their steady ~200 mbar values
0650	Arrive in lab. Stop sequence. Dial detector down to 0V. Tower = 60 mK, 1K Pot = 3.4 K / 12 mbar, G1/G2 = 740/680 mbar, MB = 2.5%
0655	Close V6 to stop circulation and allow mix to expand into still line
0700	G1/G2 = 300 mbar and falling, Still P has risen off scale, Tower has risen to 1 K
0710	Close 1K Pot speedivalve to stop pumping on pot. Leaving needle valve open. Close V4a and valve to 4He pump. Open 4He outlet to “exhaust” and close recovery valve. Turn off 4He pump.
0715	1K Pot has risen to 4.4 K. G1/G2 have fallen to 150 mbar. Tower around 1.2 K.
0720	Pump Trap 2 contents into dump. First close V1 to isolate fridge, then close V13b, open V9, open V5 to pump Trap 2 to dump.
0730	G1 has bottomed out at <2 mbar, LN2 Trap 2 is empty. Stop pumping trap out by closing V12b+speedi and V5. Then turn off 3He pump.
0735	Open V3, V1, and V4 to let mixture from fridge expand into dump.
0735	1K Pot at scale maximum 7.0 K, Sorb = 9.5 K, MC(Cernox) = 1.55 K
0740	G1/G2 = 95 mK
0740	Stop programs triggerfe2, towerfe3_01, dcrc_driver01. Disconnect power from DCRC1 and DCRC3. (DCRC4 which is connected to the NaI detector is still on.)
0840	MC(Cernox) = 1.7 K & slowly rising. G1/G2 = 110 mbar & slowly rising. Sorb = 11 K
0850	Main bath = -0.6%
0850	Remove LN2 cold trap 1 and trap 2 from bath to let warm up
0855	Turn on MC heater to 20 mW. MC temperature rises quickly to 2 K and beyond
0900	Sorb and 1K Pot temperature fall. Is this due to increased mixture boiloff from the MC/still?
1000	Sorb/1K Pot = 5.3/4.2 K. MC(Cernox) = 3.2 K, rising slowly. G1/G2 = 375 mbar, rising steadily
1030	Main bath = -1.0%, this is minimum of scale
1130	Begin disassembling lead/poly shield
1245	Finish disassembling shield
1345	Sorb/1K Pot = 9.6/max(7) K. MC(Cernox) = 7.7 K and flat (change voltage excitation from 6.3 to 63 μV). G1/G2 = 630/575 mbar and flat.
1405	Turn off MC heater for now, as a test
1420	MC(Cernox) has fallen to 6.4 K, levelling off
1420	Measure IVC pressure with cold cathode gauge on turbo pump station. IVC = 46 nbar. Before opening the valve the pressure read 15 nbar. So there's a little He in the IVC. Not so large as in Run 59 and this is at higher temperature. But not insignificant.
1430	Let 10 tube-lengths of He gas into IVC. IVC = 0.86 mbar. MC(Cernox) quickly falls to 4.6 K. Sorb/1K Pot fall too, to 7.6/5.9 K. Fridge pressure falls a little, G1 630→625 mbar
1435	Turn on MC heater to 20 mW
1445	MC = 20 mW, Sorb/1K Pot/MC(Cernox) = 7.5/5.9/4.9 K and flat, G1/G2 = 625/575 mbar and flattish
1500	Let He gas into the main bath vacuum jacket, one short (2 feet) plastic hose length. (Found a valve with hose barbs on each end to accomplish this.) Sorb/1K Pot/MC temperatures and G1/G2 pressures start to rise, IVC pressure higher too. Recovery meter spinning somewhat quickly.
1515	Metal section of recovery line is frosty but plastic part is just cool to the touch. So not as bad as last time. Recovery meter rate seems to be slowing.
1515	MC = 20 mW, Sorb/1K Pot/MC(Cernox) = 21↑/max(7)/9.9↑ K, G1/G2 = 645↑/595↑ mbar, IVC = 1.9 mbar. (↑ means rising)
1535	MC = 20 mW, Sorb/MC(Cernox) = 50↑/31↑ K, G1/G2 = 665/610 mbar, IVC = 120 mbar on cold cathode, but more like 70 mbar on mechanical gauge. Recovery meter no longer making noise.
1700	MC = 20 mW, Sorb/MC(Cernox) = 115/70 K, G1/G2 = 675/625 mbar

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