| 0010 | Fill N2 cold trap full. |
| | Isolate leak checker and open line to turbo pump. Evacuate IVC overnight. |
| 1100 | Begin pumping mixture to dump. Turn on leak checker. |
| 1150 | Dump pressure 717 mbar: mixture is dirty for some reason. Makes little sense as receovered mixture prior to cold trap cleaning yesterday was 684 mbar. Not sure if we can explain why as there is no obvious sign of a leak to atmosphere. Cryoclean mixture again through nitrogen cold trap 2. |
| | Fill N2 cold trap full. |
| 1205 | Opened valve V6 to 14.2% before mixture started flowing. A little unusual as 13.7% is usually good enough when we first start. Pressures in G1 & G2 514 mbar & 560 mbar respectively. Continue to monitor situation. |
| 1320 | Pump mixture into dump. Pressures in G1 & G2 were 571 mbar and 518 mbar respectively. It's rather concerning. Time will tell if the mixture is still dirty. |
| 1345 | Recovered 727 mbar of mixture: it's even more dirty than it was this morning. This problem has to be diagnosed before we go any further. Stop recovering mixture and open nitrogen cold trap 1 speedivalve. Attempt to cryoclean mixture through nitrogen cold trap 1. |
| 1525 | Cryocleaned mixture for about an hour and pumped it into the dump. Dump pressure is 693 mbar, which is encouraging. It may be best to try to diagnose the problem by pulling out the cold traps and running a leak check. Let's do this now. Close all valves on IGH and manual valves on dump to isolate it. Close nitrogen cold trap 1 speedivalve. Open line from nitrogen cold traps to 1 K pot pump via valves 11A & 11B. Remove nitrogen cold traps from bath and evacuate them while they warm to room temperature. |
| 1630 | Hook up leak checker to check cold trap 2. Start leak checker. |
| 1745 | Leak check on cold trap 2 performed. The background leak rate was at 3.79E-6 mbar l/s and oscillating. Although this is high we decided to press on. No leak was detected during the check of the cold trap 2 flanges, release valve and ports in to and out of the IGH, although oscillations occurred throughout. Oscillations up to 4.6E-6 mbar l/s occurred, though they did not correspond to any particular part of flanges and some occurred when He was not applied to the flanges at all (these did not seem like delayed responses). We have decided that the background is too high, and we will perform a new leak check tomorrow. At time a leak test G1=4 mbar, G2=690 mbar, and P1=16μbar. |