2025/01/08 (Wednesday)

* Lab in-personnel: Himangshu

1120	Baratron: 5.259 V (== 5.259*1000/7.6 = 691.9 mbar), G2 = 690 mbar
1130	Fill LN2 cold trap bath from bomb dewar.
1230	MC(H35)/Sorb/1K Pot = 4.63 K/–/– K, G1/G2 = 460/450 mbar, MB = 95.00%, P1 = offscale (analogue), 350 Torr (digital)
	(Closed)Close IVC valves on top of fridge. Mixture already in fridge ciculation loop
1240	Pump out line leading to 1K Pot with scroll pump (V4a open, V1a closed, 1kpot speedivalve closed). Then switch the line over to the 4He pump. Turn on 4He pump and make sure the pump exhaust is connected to recovery and open valve to recovery lines.
1141	Check pressure in 1K Pot by opening the 1kpot speedivalve with V4a closed: Mechanical gauge = ~360 mbar on G3. Baratron: 3.502 V
1241	Pump out 1K Pot by slowly opening V4a then the manual valve at the 4He pump until it just starts to make noise, once it quiets down somewhat open it up a little more. continue this until the valve is fully open.
	Leaving mixture in the fridge when starting 1K pot. P2 < 1 mbar. 1K Pot = – K(– ohm)
1150	Open 1K Pot needle valve → 30° (half the unit on the needle marks). 1K Pot → - / 20 mbar, Baratron: 3.405 V
1153	Open 1K Pot needle valve → 45°. 1K Pot → – K / 60 mbar. Closing back to 30°
1154	Open 1K Pot needle valve → 30°. 1K Pot → – K (– ohm) / 25 mbar. Baratron: 2.900 V, MC(H35) = 3.23 K
1155	Temps start to drop, mixture pressure starts to drop
1157	MC(H35) temp drops, linear at around 3.11 K, Baratron: 2.535 V
1204	MC(H35) = 2.80, 1K Pot = – / 25 mbar. G1 (fridge+dump) = 240 mbar, Baratron: 1.74 V.
1229	MC(H35) = 2.04, 1K Pot = –(– ohm) / 25 mbar. G1 (fridge+dump) = 50 mbar, Baratron: 0.454 V.
1232	We will use up all mixture this time. Close V5 and V9~~, leaving – mbar in the dump~~. Turn on 3He pump.
1249	Baratron: 0.395. Start circulation through Trap 1. V2 → Mark 1+ mark2. Condenser(G1) peaks at 350 mbar. P2 jumps to 100 mbar before falling again to 20 mbar. MC(Cernox) → 1.53 K. Still(P1) → - K / 10 Torr, Coldplate = – K, 1K Pot = –
1301	V2 → mark 3. Condenser(G1) peaks at 450 mbar. MC(H35) → 1.36 K. Still(P1) →– K / 5 Torr, Coldplate = – K, 1K Pot = –, Baratron: 0.390 V
1310	G1/G2 keeps growing over time above 600 mbar, so i opened the dump valve 9 to lower it back to 450 mbar range. Baratron: 0.589 V

1334	V2 → mark 4+ 1 full turn now. Condenser(G1) didnt peak, still at 250 mbar. MC(Cernox) → 1.14 K. Still(P1) → 1.10 K / max mbar, Coldplate = 1.05 K, 1K Pot = 1.71 K (3667 ohm)
1334	Made two full turns slowly while keeping G2 and P2 stable but no lower temp. MC temp(Cernox) seems to be flattening at 1.07 K
1345	After slowly opening VT(earlier called V6) and keeping an eye on G2, MC started showing more cooling at a point. VT(earlier called V6) must be ~12% at this point. Condenser(G1) peaks at 200 mbar. MC(Cernox) → 0.86 K. Still(P1) → 1.14 K / – mbar.
	P2 is not sensitive at this point so we can just monitor G1 while opening the VT valve
1353	VT might be fully open → 100.%. Condenser(G1) at 150 mbar. MC(Cernox) → 0.532 K. Still(P1) → 0.784 K / 300 mTorr, Coldplate = 0.713 K, 1K Pot = 1.80 K (3602 ohm)
1355	Open V10 in bursts to let the remaining mix out of the dump and into circulation. Condenser peaks slightly to 250 mbar.
1430	Tower(U28)/MC(Cernox)/Coldplate = 425 mK/6.7 mK/354 mK, Still(P1) = 0.916 K / 300 mTorr / 0 mW, G1/G2 = 220/200 mbar, 1K Pot(P2) = 45° / 1.80 K / 20 mbar, MB = 50%

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