| | Status: fridge circulation is still blocked. Warming from LN temperatures overnight with exchange gas in IVC, N2 gas in MB |
| 0920 | MC(Cernox) = 200 K, IVC = 3.0 mbar |
| | try pushing mixture through fridge in forward direction (usually throughput tests are in reverse direction): |
| 0935 | open Still gate valve and condenser valve. P1 goes down slightly, from 0.19 mbar to 0.16 mbar |
| 0940 | Fill LN cold trap Dewar. Open V9, V13a, V12a & trap1 speedivalve, to let mixture into G1 volume. |
| 0945 | Open V1 to let mix into condenser. G1 and G2 drop a little. But no increase at all on P1. We still seem to be very blocked. |
| 0950 | Turn on 3He pump. Close V13a, open V6, open V3. Pumping from fridge lines and cold trap back to dump. |
| 1010 | LN Cold Trap 1 pumped down to 1.5 mbar. Close V12a & trap1 speedivalve, remove Trap 1 from Dewar to warm up. |
| 1020 | Finish pumping all mix to dump, close valves, turn off 3He pump |
| 1025 | Open V12a and Trap1 speedivalve to monitor trapped gas from Trap 1 |
| 1040 | Trap cool to touch but above 0 Celsius. G1 = 11.3 mbar, contamination in trap. Note yesterday's mixture cleaning was rather short. |
| 1140 | Cold Trap 1 is room temperature, and G1 = 12.9 mbar. Turn on He4 rotary pump and pump out lines leading to vent valve. |
| 1207 | P2 will not pump below 3.8mbar. Something may be wrong with He4 pump. Isolate and turn off. Perhaps there's a leak somewhere leading to P2. Monitor isolated P2 over lunch. |
| 1301 | P2 now reads 19mbar. I'll look for a leak first before investigating the pump. |
| 1345 | No flange clamps seem loose enough to cause a problem. After cleaning all the flanges between the IGH and the manual valve on the He4 pump, close everything back up. Notice that P2 reads 120mbar even though it's at atmosphere. It was reading 120mbar yesterday when I had overpressurized the Main Bath, so perhaps it's behaving strangely. Turn on He4 pump and open manual valve. P2 immediately pumps down below 10mbar and continues pumping down rather quickly. |
| 1347 | P2: 1.8mbar. Leave it for a couple more minutes, then check on it. |
| 1405 | P2: 2.2mbar. Unsure if the gauge is the issue or the pump. Close manual valve on He4 pump. P2 rises from 2.4mbar to 2.6mbar. Let's see if it rises faster. |
| 1420 | P2: 3.2mbar. Nothing conclusive. Attempt to pump out G1 volume and warmed Cold Trap 1 through He4 pump to see if gauges agree and if volume can be pumped out. |
| 1425 | Opening Cold Trap 1 and G1 to P2 made G1 rise from it's initial value of 13mbar to ~20mbar, then opening V5A made it begin to drop as gas began filling into the P2 area. P2 increased to ~20mbar, and G1 fell to ~12.0mbar. The values appear stabilized. Now to turn on the He4 pump and open the manual valve. |
| 1430 | Both G1 and P2 pumped down somewhat slower than normal. P2 did get down to a value of 0.8mbar, but then began slowly rising again. G1 pumped down to 2.0mbar, though by this time P2 had increased to 1.4mbar. Close manual valve and turn off He4 pump to see if pressures rise indicating a leak of some kind. |
| 1435 | G1: 2.0mbar, P2: 3.0mbar. |
| 1445 | G1: 2.3mbar, P2: 3.6mbar. |
| 1457 | G1: 2.7mbar, P2: 4.0mbar. |
| 1505 | G1: 3.0mbar, P2: 4.0mbar. |
| 1520 | Still can't pump below ~2mbar on P2 with He4 pump. Replace with scroll pump, and P2 immediately pumps below 1mbar. Currently at ~0.03mbar. Open V5A to pump out Cold Trap 1 with scroll pump. |
| 1545 | G1: 2.0mbar, P2: .017mbar. Close all valves on IGH, and manual valve on scroll pump. Turn off scroll pump. |
| 1600 | Lower dewar ~1foot and place blower on top to help warm up fridge for tomorrow. |