2019/10/15 (Tuesday)

	Status: Tower assembled, ready for installation. 2nd attempt at Run 71 cooldown.

Fridge
1000	Notice that the Still heater is on. It's been on for over a week with the IVC open. That's probably not a good idea. Turning it off now.
1010	Check contents of warm LN2 Trap 1: 4 mbar. Pump out with scroll pump.
1015	Check contents of warm LN2 Trap 2: 6 mbar. Pump out with scroll pump.
1050	Check the return-line volume, between V1 and the condenser valve (this includes the LHe Trap). 3.6 mbar. Pump out with scroll pump.

Tower
1105	Move tower into fridge clean tent
1110	DISASTER. While moving the tower around on its stand, it clanged around a bit - and fell apart! As has happened at several other facilities over the last couple of years, one of the graphite tubes broke.

What can we do?

Replace. Nader can send us back the tower we sent him (he considers it “ours”, that it's “on loan”. I'm not certain that the tower we took from Soudan was ours to take or not.) It has a bad face but I don't think we ever need all the faces.
Repair. This would entail at least the graphite tube and complete rewiring. Would we remove the tube and glue in a new one? Epoxy the existing tube back together? How plausible is this?
Redesign. A new tower entirely. Maybe a better one optimized for no-FET operation. Well that's a lot of work. An old prototype SNOLAB tower? Probably those aren't very good.

Some of the goals of this run may be achievable without a proper tower, if we can wire the source mover.

Run 71 Goal	Doable without wired detector?	notes
See if source mover works when cold	Yes	Can see it hit its endstops
See impact of source mover on base temperature	Yes
See impact of source mover on detector	No
See how well the indium source blockers work	No	Even with a wired detector this is contingent on the source mover not making the detector inoperable, although we expected at least to see events in the charge channels
Get some event position data for 100mm iZIP	No	Note this is contingent on the source mover not harming detector performance

So 2 of 5 goals could be satisfied without a wired detector. But not sure exactly how we would even wire the source mover with a broken tower.

Update: Nader said he will send us our old tower this week.

1435	Checking inventory of 3inchX1cm housings because TAMU needs them. We have what looks like 4 housings that size.

Four housings:

with a detector in it, I'm guessing G9. One DIB with two working LEDs.
empty, with one DIB that doesn't appear to have LEDs
filled with capacitors, 2 DIBs, looks like both have LEDs but not wirebonded. DIBs have been soldered onto, may not be good
empty, no DIB slots, unusual design, probably not usable

Clamps:

DIBs: