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Message ID: 2622     Entry time: Monday, June 24, 2024, 14:37
Author: Carla Babcock 
Category: South Hot-Cell 
Type: Development 
Module: TM3 
Target/Number: UCx#44 
Subject: Inspection of TM3 and UCx#44 after no-protons run 

TM3 and UCx#44 ran in ITE but issues with the cyclotron prevented proton beam delivery. Nonetheless, the target was heated and provided stable beam to TITAN as well as for tuning and some tests.

Results of inspection of TM3 module after run:

The module looked pretty good. There were no marks on the polished surface of the containment box, next to the water blocks, that were visible. But we didn't remove the box, only looked with the camera and it was visible by turning the module. So some things may have been hidden. There were some black marks on the door, near the bolts that hold in the handle (see attachment). This seems a very unlikely spot for sparking as the fields should be considerably lower than at the target handles, lower down. Maybe the spots are from oil left on the door that had a chemical reaction? There is one very faint matching spot on the top of the copper trident connector, but it doesn't look much like a spark mark. The other two marks have no corresponding mark on the source tray. There were no marks on the ground electrode, or anywhere else on the source tray. There was a scuff on one of the trapezoidal insulators, but it could have happened during installation.

 

Results of inspection of the target after run:

The FEBIAD target developed the same cathode short we have seen on almost every FEBIAD we run online - a high resistance short from cathode to HVC that prevents voltage on the cathode. This time the short remained after cooling the target, and David measured 208kOhms with the ohmmeter on the module top (11kOhms with the megger). We used a multimeter in the hot cell to test after the target had been dismounted and we found no short. So it must be related to either the position of the target (upright vs face down) or time (a conductive trace on an insulator oxidizes and becomes non-conductive again) or some pressure/shaking during the de-installation.

There weren't many marks on the target - a faint mark near where the faint mark on the copper trident was observed, some marks on the EE which had no counterparts on the ground electrode. See pictures.

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