To deliver stable beam to RadMol, started heating UCx#43 up again. Target was overheated during initial conditioning in Nov but then ran well for 4 weeks. During the run time, the TGHT voltage jumped around and this was reflected in the ion current, but yields seemed unaffected.

When re-heating it, the TGHT voltage was very unstable and once it got to 440A, it went into voltage limiting mode. We ramped down and it was still voltage limiting, but turning things off solved it. We ramped back up and it did about the same thing. TBHT voltage and current remained steady. Looks like a heat generated issue.

Measured the resistance in the lines from the electrical room. Resistance of the lines to ITE should be 1.19mOhms for TGHT and 1.95mOhms for TBHT. TBHT positive to negative had a resistance of 7.9mOhms from the electrical room today, and 5.7mOhms on module top when measured Nov. 8. This seems to track.

TGHT positive to negative was measured at 27.6mOhms today (and was jumping around), whereas it was 7.14m Ohms on Nov. 8.

10V @ 440A is 22.7mOhms, so it makes sense that it limited. Tried with increased voltage (up to limit of 16V) but this didn't help. Declared the target dead on Jan. 11.

David measured resistances on the module top and found (in mOhms):

A-B = 27 (TGHT)

A-C = 7.473

A-D = 6.380

B-C = 26.053

B-D = 25.569

C-D = 5.212 (TBHT)

So looks like the tube is broken on the B side.