2020/02/07 (Friday)

Previous Day

0900	Check contents of warm LN2 Trap 1: 4.5 mbar. Pump out with scroll pump.
0905	Check contents of warm LN2 Trap 2: 5.0 mbar. Pump out with scroll pump.
0915	Start cryocleaning mixture through LN2 Cold Trap 1, V6 = 12.4%
0920	Increase V6 → 12.7% to restart flow
0925	Increase V6 → 12.8% to speed up flow
1010	Increase V6 → 12.9% to speed up flow
1020	Stop cleaning through Trap 1 after 65 min. G2 flow pressure was 570-650 mbar. Pump mixture to dump. Removed 8.4 mbar.
1040	Start cryocleaning mixture through LN2 Cold Trap 2, V6 = 12.8%
1050	Increase V6 → 13.1% to restart flow
1115	Increase V6 → 13.2% to restart flow
1120	Increase V6 → 13.3% to speed up flow
1200	Stop cleaning through Trap 2 after 80 min. G2 flow pressure was 565-770 mbar. Pump mixture to dump. Removed 6.0 mbar.
1210	Check contents of warm LN2 Trap 1: 8.4 mbar. Pump out with scroll pump.
1220	Start cryocleaning mixture through LN2 Cold Trap 1, V6 = 12.6%
1225	Increase V6 → 13.0% to restart flow
1240	Increase V6 → 13.1% to restart flow
1300	Increase V6 → 13.2% to speed up flow
1315	Increase V6 → 13.3% to speed up flow
1325	Stop cleaning through Trap 1 after 65 min. G2 flow pressure was 575-860 mbar. Pump mixture to dump. Removed 5.9 mbar.
1350	Check contents of warm LN2 Trap 2: 6.0 mbar. Pump out with scroll pump.
1415	Start cryocleaning mixture through LN2 Cold Trap 2, V6 = 12.4%
1430	Increase V6 → 13.1% to restart flow
1455	Increase V6 → 13.2% to restart flow
1525	Stop cleaning through Trap 2 after 70 min. G2 flow pressure was 575-620 mbar. Pump mixture to dump. Removed ??(>3.6) mbar.

1000	As an experiment we'll try wiring one channel with copper wires rather than the standard side coax. This is ala CUTE towers, Tsuguo's pigtails. He says 32 gauge copper has sufficiently low resistance below 1K.
	I used 26 gauge copper wire, twisted pair between adapter boards for a DIB and for a tower connection. I connected Channel C to use on DIB3 (one channel only, Side1pA).

1200	As another experiment we are planning a test of screw terminals to connect our NbTi wire to tower wires. The idea is to use superconducting screw terminals so we made two aluminum blocks with 2-56 tapped holes and ordered aluminum screws and washers.
1230	Cut a 16 cm length of NbTi wire and used 150 sandpaper to remove the insulation from about 3 cm on each side. Reads about 27 Ohm with the meter.
1400	Finish two aluminum blocks with 2-56 threaded holes. Also build aluminum washers. We ordered aluminum screws but won’t get them in time, so do the screw terminal test we will use what appear to be steel screws.
1430	Put two layers of Kapton tape on source mover base plate, then attach screw terminal bases to the Kapton with GE varnish.
1500	Clamp ends of NbTi wire between Al washer and Al block, then large-ish gauge silver-plated copper (SPC) wire between that washer and another above. Screw terminal setup reads 17.8 Ohm, no shorts to chassis. We taped the NbTi wire down to the plate but probably want to redo that, so that it’s not very well heat sunk, for purposes of testing.

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