2020/10/06 (Tuesday)
- Lab in-person: Matt
- Virtual partner: Nick&Anthony/group meeting/Zach
| Setup | Run 73. DIB 1/3/4 → Stripline 43/48/41 → pi-filters 1/2/3 → Cable 3/1/2 → nothing/nothing/accessory_interposer → HV_Conn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC55(1)-master; DCRC33(2) → HV control. DCRCs off. Lead/poly shield erected (4 lead walls, 2 poly walls). |
|---|---|
| Status | Warmed up to deal with clogged 1K Pot. Mixture in dump, CVJ and IVC pumped out. 1K Pot pumped out and isolated. |
| 1100 | Matt enters lab |
| 1110 | Matt Fritts body temperature = 97.7 F |
| 1150 | MC(Cernox) = 287.4 K |
| 1155 | Turbo on IVC = 25 nbar. With Turbo valved out for a minute, IVC = 400 nbar. |
| 1205 | Check contents of warm LN2 Trap 1/2: 17.8/3.0 mbar. Pump out both with Scroll Pump |
| 1235 | Check fridge pressures: LHe trap/Condenser/Still = 14.7/1.5/1.62 mbar. Pump out with Scroll Pump |
| 1310 | Put LN2 Trap 1 in bath Dewar and fill bath |
| 1315 | With 1K Pot speedivalve and needle valve closed, pump out Main Bath with scroll pump. |
| 1320 | Check 1K Pot pressure at P2: 30 mbar. Pump out with Scroll Pump. |
| 1320 | Open 1K pot speedivalve and needle valve (5 turns) and V1a and pump out 1K pot volume and MB to < 1 mbar on P2. |
| 1325 | Close off scroll pump, then pressurize bath and 1K Pot (both sides) to about 0.75 bar with helium. Pump it out again with scroll pump to < 1 mbar. |
| 1335 | Close 1K Pot needle valve and pump out 1K Pot from Speedivalve side alone, then isolate it. Pressurize MB with helium to 200 mbar+1atm on G3. |
| 1350 | Perform 1K Pot throughput test (at MC = 287 K). 1K Pot pumped out and isolated from MB. MB is full of helium gas. Pump out 1K Pot, then stop pumping and watch the pressure rise at P2. Then repeat, but after stopping pumping open the needle valve a certain amount. Select a starting pressure then wait about 30 seconds and record a final pressure. Needle valve = 0/10/20/30/60° → 0.18/0.74/1.2/2.5/8.8 mbar/min. |
| These are actually pretty close to the Oct 1 measurements at 230 K, when I thought it may still be clogged. Maybe the slower rate you'd expect now from being warmer is compensated by the faster rate you'd expect if the clog is gone. | |
| 1400 | With 1K Pot speedivalve and needle valve closed, pump out Main Bath with scroll pump. Once P2 < 1 mbar, open 1K pot speedivalve and needle valve (5 turns) to pump out 1K pot volume to 0.5 mbar on P2. |
| 1405 | Pressurize main bath and 1K Pot (both sides) with helium to 355 mbar +1atm on G3, then close 1K Pot speedivalve and needle valve. |
| 1410 | Let 5.4 mbar He exchange gas into IVC. |
| 1415 | As on 2020 Sep 17, we will flow mixture through the fridge during LN2 cooldown. Let mixture from dump through cold LN2 Trap 1 to fridge, both sides. Then we'll separate the sides and circulate with V6 open partially and mix open to dump. V9, V13a, V12a+speedi, V1, Condenser speedi, Still gate valves open, 3He pump on. Now open V6 to 12.8%. |
| 1420 | P1 falls to <1 mbar |
| 1420 | Try closing V12a speedivalve. G1 falls as it should, showing we have throughput. Falls at 11 mbar/min. Open V12a speedivalve again. |
| 1425 | Circulation pressures settling to G2/G1/P1 = 683/744/0.4 mbar |
| 1425 | MC(Cernox) = 287.8 K, Sorb = >249 K (max), IVC = 5.4 mbar, G2/G1/P1 (circulation) = 683/744/0.45 mbar, Level resistor = 0.990 kΩ |
| 1435 | Begin LN2 transfer. |
| 1440 | Concerned because LN2 transfer seems slow. May need to pressurize the LN2 Dewar. |
| 1445 | MC(Cernox) = 287.8 K, Sorb = >249 K (max), IVC = 5.4 mbar, G2/G1/P1 (circulation) = 686/748/2.6 mbar, Level resistor = 0.991 kΩ |
| 1450 | Try pressurizing the LN2 Dewar through the Vent port. Increase cylinder regulator pressure 6→10 PSI. Wait a few minutes - the pressure on the LN2 Dewar gauge rises to 10 PSI. At that point, close Vent valve and stop pressurizing. |
| 1455 | MC(Cernox) = 287.2 K, Sorb = >249 K (max), IVC = 5.4 mbar, G2/G1/P1 (circulation) = 688/749/4.0 mbar, Level resistor = 0.995 kΩ |
| 1500 | Looks like transfer is going faster now. Dewar pressure has relaxed to around 7 PSI, I think it was around 5 or less before I pressurized it. |
| 1505 | MC(Cernox) = 282.8 K, Sorb = >249 K (max), IVC = 4.6 mbar, G2/G1/P1 (circulation) = 689/749/6.5 mbar, Level resistor = 1.001 kΩ |
| 1515 | Noticed Dewar pressure had fallen to about 5 PSI again, so pressurized it up to 8 PSI through vent, then closed vent valve again. |
| 1520 | MC(Cernox) = 269.0 K, Sorb = >249 K (max), IVC = 4.0 mbar, G2/G1/P1 (circulation) = 690/749/24 mbar, Level resistor = 1.014 kΩ |
| 1520 | Close V12a speedivalve for 2 minutes to assess throughput. (Condenser pressure G1 should fall.) G1 falls at 13.1 mbar/min. Open V12a speedivalve again. |
| 1545 | MC(Cernox) = 232.7 K, Sorb = >249 K (max), IVC = 4.0 mbar, G2/G1/P1 (circulation) = 690/746/max mbar, Level resistor = 1.031 kΩ |
| 1605 | MC(Cernox) = 211.7 K, Sorb = >249 K (max), IVC = 3.0 mbar, G2/G1/P1 (circulation) = 688/743/max mbar, Level resistor = 1.053 kΩ |
| 1605 | Close V12a speedivalve for 2 minutes to assess throughput. (Condenser pressure G1 should fall.) G1 falls at 17.5 mbar/min. Open V12a speedivalve again. |
| 1615 | Definitely this is a slower than normal transfer. Around half the normal speed maybe. I have occasionally been repressurizing the LN2 Dewar back up to about 9 PSI. |
| 1630 | MC(Cernox) = 180.8 K, Sorb = >249 K (max), IVC = 2.5 mbar, G2/G1/P1 (circulation) = 685/738/max mbar, Level resistor = 1.108 kΩ |
| 1650 | MC(Cernox) = 152.0 K, Sorb = >249 K (max), IVC = 2.2 mbar, G2/G1/P1 (circulation) = 680/732/max mbar, Level resistor = 1.197 kΩ |
| 1650 | Close V12a speedivalve for 2 minutes to assess throughput. (Condenser pressure G1 should fall.) G1 falls at 31.0 mbar/min. Open V12a speedivalve again. |
| 1710 | MC(Cernox) = 131.7 K, Sorb = 218.1 K, IVC = 1.9 mbar, G2/G1/P1 (circulation) = 674/724/max mbar, Level resistor = 1.266 kΩ |
| 1720 | MC(Cernox) = 124.3 K, Sorb = 192.8 K, IVC = 1.9 mbar, G2/G1/P1 (circulation) = 669/719/max mbar, Level resistor = 1.289 kΩ |
| 1720 | Close V12a speedivalve for 2 minutes to assess throughput. (Condenser pressure G1 should fall.) G1 falls at 42.2 mbar/min. Open V12a speedivalve again. |
| 1730 | MC(Cernox) = 119.2 K, Sorb = 176.3 K, IVC = 1.9 mbar, G2/G1/P1 (circulation) = 665/715/max mbar, Level resistor = 1.302 kΩ |
| 1730 | Stop LN2 transfer. Pull out Level Resistor and put ping-pong ball on MB exhaust port. |
| 1735 | Matt leaves lab |
| 1850 | MC(Cernox) = 91.3 K, Sorb = 138.3 K, G2/G1/P1 (circulation) = 627/673/max mbar |
| 1850 | Matt Fritts body temperature = 98.3 F |
| 1900 | Close V6 and stop circulation pump. |