UMN CDMS Wiki archive
start › cdms › k100 › run_diary › 20250726

2025/07/26 (Saturday)

Previous Day

  • Lab in-personnel: Himangshu, Yan
13:00 Next step is the throughput test.
Throughput test procedure, Cold Trap 1:
  1. All mixture in dump, LN2 trap 1 is cold, condenser & still valves open (3He pump on - optional)
  2. Open V9, V8, V3, V5. Wait for G1 to be close to G2 (within 100 mbar).
  3. Close V3 and V5, open V1
  4. monitor G1
1230 Perform mixture throughput test at MC = 77 K using above procedure with 3He pump on. Let G1 rise to ~500 mbar before Step 3, then it falls to ~50 mbar, then rises. Throughput = ~25 mbar/min.
xxxx Perform mixture throughput test at MC = 300 K using above procedure with 3He pump on. Let G1 rise to 538 mbar before Step 3, then it falls to 42 mbar and starts to rise. Throughput = 6.1 mbar/min.
10:57 Begin LN2 transfer
1059 MC(Cernox) = 297.6 K, Sorb = >249 K (max), IVC = 5.4 mbar, G2/G1/P1 (circulation) =– mTorr, Level resistor = – kΩ.
1123 MC(Cernox) = 278 K, Sorb = –K (max), IVC = 4.0 mbar, G2/G1/P1 (circulation) =680/700/85 mTorr, Level resistor =– kΩ.
Throughput test: ~10 mbar/min
1136 MC(Cernox) = 242 K, IVC = –, G2/G1/P1 (circulation) = 680/700/100 mTorr, Level resistor = – kΩ.
1157 MC(Cernox) = 187 K, IVC = –, G2/G1/P1 (circulation) =680/710/170 mTorr, Level resistor = – kΩ.
Throughput test: ~18 mbar/min
1234 MC(Cernox) = 142.5 K, IVC = –, G2/G1/P1 (circulation) =680/710/400 mTorr, Level resistor = – kΩ
Throughput test: ~40 mbar/min
1308 The steam from the MB exhaust port is gone for some reason? why? closed the valve from the LN tank to stop LN transfer for now (to not overpressure the MB). There should still be LN in the tank, but the relief valve is reading 0 psi now. Probably enough LN already.
1310 Himangshu told me that close to being filled, the steam will go away. Good.
1314 MC(Cernox) = 117 K, IVC = –, G2/G1/P1 (circulation) =680/710/600 mTorr, Level resistor = – kΩ
Throughput test: ~48 mbar/min
1325 The LN fill line and exhaust port has defrosted. Put ping-pong ball on MB exhaust port.
1326 Close V2 and turn off 3He pump.
1329 MC(Cernox) = 108.6 K. Let's hope it will get tot 77K.
2034 stable at 77K now.

Next Day