2015/02/26

0840	With G1=127 mbar, G2=110 mbar, P1=85 ubar, mixing chamber temperature has been oscillating throughout the night ranging from ~700 mK to 1.3 K. Unsure why G1 and G2 have also been rising over time, possibly mix is dirty. Fill cold trap. Check 1K Pot temperature by plugging in Fischer connector #1. 1K Pot currently at 1.56 K. Unplug both Fischer connectors for the next hour.

Figure 1: Mixing Chamber (H35) Overnight Oscillations in Temperature	Figure 2: G1 and G2 Overnight Pressure Oscillations (mbar)

Figure 3A and 3B: Overnight Oscillations in H35 temperature (K) and P1 pressure (mbar)

0940	Pump mixture to dump to initiate single shot test. Mixing chamber temperature at 978mK and begins rising. G1: 130mbar, P1: 95ubar, G2: 112mbar, 1K Pot: 1.543K. Single shot results show that Mixing chamber temperature rises from 1.01 K (G2=123 mbar), to 1.10 K (G2=292 mbar) in 79 seconds. Mixing chamber temperature then falls to 991 K (G2=294 mbar) in 42 seconds. It then rises for another 12 seconds to 1.00 K (G2=295 mbar) before falling again for 54 seconds until it reaches 957 K (G2=299 mbar). It then continues to rise. Overall this could just be oscillations in temperature as those that were seen before. Results are inconclusive.
1000	Cease pumping on 1K Pot to warm up while pumping to dump. Mixing chamber temperature stabilizes at 1.05K. No oscillations seen, as shown in Figure 4.

0940

Pump mixture to dump to initiate single shot test. Mixing chamber temperature at 978mK and begins rising. G1: 130mbar, P1: 95ubar, G2: 112mbar, 1K Pot: 1.543K. Single shot results show that Mixing chamber temperature rises from 1.01 K (G2=123 mbar), to 1.10 K (G2=292 mbar) in 79 seconds. Mixing chamber temperature then falls to 991 K (G2=294 mbar) in 42 seconds. It then rises for another 12 seconds to 1.00 K (G2=295 mbar) before falling again for 54 seconds until it reaches 957 K (G2=299 mbar). It then continues to rise. Overall this could just be oscillations in temperature as those that were seen before. Results are inconclusive.

1000

Cease pumping on 1K Pot to warm up while pumping to dump. Mixing chamber temperature stabilizes at 1.05K. No oscillations seen, as shown in Figure 4.

Figure 4: Mixing Chamber (H35) Morning Oscillations in Temperature followed by Single Shot Test and Mixture Recovery

1515	G1=0.7 mbar, G2=650 mbar, P1=14 ubar. Close all valves on IGH. Open gate valve and V6 to collect mixture still in fridge.
1540	G2=656 mbar, G1=0.5 mbar, P1= 12 ubar. Close gate valve and V6. Close manual dump valves (just in case), and remove He cold trap from bath and open to P2 (scroll pump speedivalve closed).
1610	G1=2.2 mbar, P2=5.0 mbar worth of waste collected from He cold trap. G2=650. Open scroll pump speedivalve and pump of He cold trap for several minutes. Isolate cold trap by closing V1 and V2. Pull LN2 cold trap 1 from dewar and open cold trap to P2 (scroll pump speedivalve closed).
1650	Complete check for ground loops. Found evidence of shorts due to bellow from IVC to turbo pump and hoist cables touching dewar. After correcting these issues, fridge was floated, with 1.6 mV between fridge frame and orange ground socket.
1700	P2=8 mbar or waste collected from cold trap 1. Pump on cold trap 1 and He cold trap. Do a quick (5 minutes) spray with heat gun on each.
1720	Stop pumping on cold traps and put them back in their baths, fill LN2 cold trap dewar full. Start the 1K Pot. G1=1.8 mbar, G2=652 mbar and P1=34 ubar. Prepare to start condensing procedure. Start LHe transfer (26.3%).
1745	Close V9 with 302 mbar left in dump (circulate 350 mbar).
1750	G1=89 mbar, G2=68 mbar. Start circulating procedure.
1602	Finish circulating procedure. G1=149 mbar, G2=160 mbar, P1=0.4 mbar, mixing chamber temperature at 1.04 K and all values are dropping.
1810	End LHe transfer (79.1%)
1815	Lower 1K Pot temperature to 1.52 K.