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2025/07/29 (Tuesday)

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  • Lab in-personnel: Himangshu, Yan
Status Ready for LHe transfer. MC(Cernox) = 77.47 K, up from 77.24 K yesterday after pumping out the exchange gas.
0850 Trap warmed to room temperature over night. open V3, the volume increased by 70 mBar.
0900 Use scroll to pump out the trap.
0910 Refill the cold trap.
0925 Close valves and stop the scroll. Reinsert the cold trap into the LN dewar.
0930 Check leak rate from the IVC. Switch from turbo to LD. Reading 1.5e-8. Switch back to turbo.
1100 Begin LN blowout. math bath inlet pressure: 2.5 psi + atm . LN is coming out.
1113 took out the copper coil pipe on the Helium exhaust line for Mark to fix the leak.
1115 LD reading stably 1.5e-8 leak rate.
1134 Saw e-3 level leak after halfway past initial blowout. Suspect leak is from the lower indium seal. Prepare to warm up.
1140 Collect mix back to dump.
1140 change MB fill port with a rubber stopper (lightly tapped to relieve pressure if needed).
1200 Introduce N2 gas into the OVJ, to 22 mbar.
1230 Introduce N2 gas into the IVC, to ~230 mbar.
1255 MC at 79.7 K, still 77.2 K. Assuming 0.2 K/min (aggressive), we will reach 250 K in 14 hours. 300 K in 24 hours.
1400 MC(Cernox) = 93.67 K, warming at 12.48 K/hr.
1525 MC(Cernox) = 110.1 K, still = 111.7 K.
1530 start cryocleaning.
1750 start collecting the mix back to dump.
1800 leak check the new pressure gauge by spraying helium around.
1830 LD baseline: 3.6e-7; spray helium all over the new MXP pressure gauge and then the vacuum manifold. peak leak rate is 4.9e-7. looks good.
1900 secured dump. took out cold trap to warm to room temperature overnight.
1900 MC(Cernox) = 150 K; still = 156.3 K.
2350 MC(Cernox) = 190 K; still = 200.4 K.

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