UMN CDMS Wiki archive
start › cdms › k100 › run_diary › 20170123

2017/01/23 (Monday)

Previous Day

Status: Bath at room temperature. He exchange gas in IVC. Small leak at top of stripline tube. Mixture is in dump, fridge evacuated.
0835 Trap 2 has been warm since Saturday. Trap 2 (G1) = 18.6 mbar, after 95 minutes cryocleaning. A little less than after the Friday cleaning.
0840 IVC = 6.3 mbar. Crept up from 4.6 mbar on Saturday, a little concerning. Pump out IVC and refill with 4.6 mbar He exchange gas.
0850 Pump out Trap 2, put it back in LN2 bath, fill LN2 trap bath
0900 Flush main bath then pressurize with He gas
0905 Begin cryocleaning mixture through Trap 2
0910 Begin LN2 transfer
0915 MC (Cernox) = 290 K, IVC = 4.6 mbar
0920 MC (Cernox) = 290 K, IVC = 4.0 mbar
0940 MC (Cernox) = 276 K, IVC = 3.4 mbar
1005 MC (Cernox) = 240 K, IVC = 2.5 mbar
1005 Stop cryocleaning, pump mixture back to dump
1005 MC (Cernox) = 207 K, IVC = 2.2 mbar, level resistor = 1.318 kΩ
1025 Open up fridge lines to Trap 1 (through v12a+speedivalve, v3, v1, condenser speedivalve, still gate valve). Then close V12a+speedivalve and let mixture from G2 volume into Trap 1 through v13a. (v9 is closed, so most of the mixture is still in the dump.)
1005 MC (Cernox) = 194 K, Sorb = 248 K, IVC = 2.2 mbar, level resistor = 1.336 kΩ
Stop LN2 transfer
1035 Try throughput test with the small amount of mixture in the G2 volume only. Before opening V12a, G2 read 480 mbar. After letting mixture into still, G1 rose to 230 mbar, then after isolating the still and opening the condenser to G1, G1 fell to minimum of 14 mbar. Then G1 began to rise, so there is throughput :). Throughput = 3.2 mbar/min.
1050 Allow mixture to trickle into still and condenser from dump through Trap 1 and partially-open v12a speedivalve.
1055 MC (Cernox) = 168 K, Sorb = 200 K, IVC = 1.9 mbar
1135 MC (Cernox) = 136 K, Sorb = 155 K, IVC = 1.6 mbar
1250 MC (Cernox) = 105 K, Sorb = 134 K, IVC = 1.6 mbar
1310 Pump mixture out of fridge, back to dump and Trap 1
1315 MC (Cernox) = 98 K, Sorb = 132 K, IVC = 1.4 mbar
Will perform throughput test @ about 100K through Cold Trap 1
  1. All mixture in dump, LN2 traps cold, condenser & still valves open (3He pump on - optional)
  2. Open V9, V13a, V12a+speedivalve, V3. Wait for G1 to be close to G2.
  3. Close V12a+speedivalve and V3, open V1
  4. monitor G1
1320 Perform throughput test. G1 reaches maximum of 640 mbar before isolating mix in still, then falls to minimum of 85 mbar after opening G1 to condenser, then begins to increase. Throughput = 45 mbar/min. Lower than Oct 13 when it was 57 mbar/min, but this is a higher temperature so we expect it to be lower.
1340 Open fridge lines (condenser and still) to Trap 1. Leaving v13b closed, so some mixture is still in the dump. Turn off 3He pump.
1345 MC (Cernox) = 92 K, Sorb = 130 K, IVC = 1.4 mbar
1400 MC (Cernox) = 89.6 K, Sorb = 129.3 K, IVC = 1.4 mbar
1405 Begin blowing out LN2 from main bath
1415 G3 (main bath) pressure has fallen from 600 to 175 mbar, hose limp, blowout is maybe finished
1425 MC (Cernox) = 86.6 K, Sorb = 131 K, IVC = 1.4 mbar
MC is still cooling (but Sorb is warming). Trying to decide when to pump out the exchange gas during the blowout. Probably wait until MC stops getting colder.
1440 Pump out main bath with scroll pump. P2 falls below 1 mbar after 8 minutes so it looks like the bath is empty.
1450 Pump out 1K pot with scroll pump, too
1455 Fill main bath with He gas. Also let some He into the 1K Pot during this process.
1455 MC (Cernox) = 85.0 K, Sorb = 141 K, IVC = 1.4 mbar
1455 Begin pumping out IVC with scroll pump
1503 Begin LHe transfer
1505 Let 46 μbar He transfer gas into IVC
1510 MC(Cernox) = 84.8 K, Sorb = 142 K, IVC = 46 μbar, Fridge(G1) = 610 mbar
1535 MC(Cernox) = 78.8 K, Sorb = 108 K, IVC = 22 μbar, Fridge(G1) = 590 mbar
1540 Perform electrical check on detector as on Jan 18. Some things are the same, some problems went away:
  • On DIB4, there appears to be a 60 nS (15 MΩ) short to chassis from the qInner wire between the feedback resistor, coupling capacitor, and FET gate. This could be either in the side coax or the FET card. (symptoms: chassis→qIfeedback = 15 nS, chassis→qIsource = 60 nS, chassis→qIdrain = 50 nS, qIfeedback→chassis = 18 nS, qIdrain→chassis = 0.1 nS, qIsource→chassis = 0.1 nS.
  • On DIB3 there is a 26 nS short to chassis from qIfeedback
  • On DIB1, LED1 seems to leak in the reverse direction at 309 kΩ. (This was seen at the detector tests too)
1555 MC(Cernox) = 66.8 K, Sorb = 56 K, IVC = 12 μbar, Fridge(G1) = 400 mbar
1605 1K Pot temperature falls into readable range, <7 K
1610 MC(Cernox) = 58.9 K, Sorb = 9.1 K, IVC = 8.6 μbar, Fridge(G1) = 290 mbar
1615 MC(Cernox) = 56.9 K, Sorb = 7.9 K, IVC = 8.6 μbar, Fridge(G1) = 285 mbar, MB = 17.5%
1625 Remove Trap 2 from LN2 bath. Fill LN2 bath.
1635 MC(Cernox) = 47.3 K, Sorb = 7.0 K, IVC = 7.4 μbar, Fridge(G1) = 265 mbar, MB = 48.9%
notice that sound from the recovery meter has the same rhythm as the Xmas song “Sleigh Ride”
1645 MC(Cernox)/Sorb/1K Pot = 42.4/6.9/5.4 K, IVC = 7.4 μbar, Fridge(G1) = 260 mbar, MB = 76.4%
1655 Stop LHe transfer @ 90.4%
1655 Fridge pressure went up when transfer was ended, to 340 mbar, then fell again
1700 MC(Cernox)/Sorb/1K Pot = 33.9/6.6/5.2 K, IVC = 7.4 μbar, Fridge(G1) = 330 mbar
1715 MC(Cernox)/1K Pot =23/4.5 K, Fridge(G1) = 337 mbar. (NOTE: These measurements were taken at 17:30 using VI graphs).
1720 MC(Cernox) = 17 K
1730 MC(Cernox)/Sorb/1K Pot = 4.5/5.7/4.5 K, IVC = ?? μbar, Fridge(G1) = 345 mbar. Noticed steep temperature drop and started pumping on IVC with turbopump before we could note IVC pressure.
1737 MC(Cernox)/Sorb/1K Pot = 4.3/6.1/4.7 K, IVC = 34 nbar, Fridge(G1) = 356 mbar.
1752 MC(Cernox)/Sorb/1K Pot = 4.29/6.5/5.4 K, IVC = 22 nbar, Fridge(G1) = 373 mbar.
1819 MC(Cernox)/Sorb/1K Pot = 4.37/6.7/5.2 K, IVC = 22 nbar, Fridge(G1) = 385 mbar.
1900 MC(Cernox)/Sorb/1K Pot = 4.40/6.8/5.3 K, IVC = 22 nbar, Fridge(G1) = 396 mbar.
1920 MC(Cernox)/Sorb/1K Pot = 4.41/6.9/5.4 K, IVC = 25 nbar, Fridge(G1) = 399 mbar. Main bath=85.5% Looks like things are good, heading out. [image not archived: cool.svg]

Next Day