Tuesday, December 02, 2024, 15:35 - Target loaded into the test stand
Thursday, December 03, 2024, 14:33 - as per elog entry 1033, test stand has been changed to CATHODE mode, and wiring within the Faraday cage has been altered appropriately. Additionally, a GeMov resistor has been added to potentially reduce the sparking problems that have previously tripped the TGHT power supply
Thursday, December 04, 2024, 10:00 - Roughing pump having trouble reaching suitable vacuum - possible replacement required.
Thursday, December 05, 2024, 13:37 - Turbo pumps on
Monday, December 09, 2024, 09:51 Vacuum at 3e-7 T
Monday, December 09, 2024, 12:10 Water cooling switched on, monitored vacuum. No change to vacuum.
Monday, December 09, 2024, 16:58: TGHT / TBHT ramping to 580A/230A at 1A/30.
Tuesday, December 10, 2024, 11:14 increasing COIL current 10A at a time, monitoring vacuum pressure
Tuesday, December 10, 2024, 18:42 COIL at 100A after allowing pressure to fall to reasonable levels throughout the day. allowing to stabilize for a few hours.
Tuesday, December 10, 2024, 19:00 vacuum plateauing now, awaiting decrease to 1/3 of peak before reducing COIL to zero
Tuesday, December 10, 2024, 19:37 - vacuum at 9.9e-7T. dropping COIL to 0A
Wednesday, December 11, 2024, 10:27 increasing BIAS/EE/EZL to 30/1.5/13 kV
Wednesday, December 11, 2024, 11:30 TGHT TBHT adjusted to 490/290A
Wednesday, December 11, 2024, 13:47 degaussing script not currently available. For now. will examine beam extracted at CAT=120V COIL=40A
Wednesday, December 11, 2024, 14:27 The CATHODE is completely shorted. cannot hold even 1 volt and is currently limited immediately upon switching on cathode bias power supply.
 
Wednesday, December 11, 2024, 15:02 dropped bias/ee/ezl to 0
Wednesday, December 11, 2024, 15:02 Must cool target to investigate Cathode short. Prior to installation, target isolation was confirmed. If the cathode dropped to contact the copper plate shielding the coil, this would be evidence to support keeping the retainer.
Thursday, December 12, 2024, 09:24 after cooling, cathode power supply was checked to see if shorted and it is indeed still shorted out.
Thursday, December 12, 2024, 09:25 turning off turbo pumps to spin down
Thursday, December 12, 2024, 11:30: venting chamber
Friday December 13: after venting the chamber and removing the target. The target appears to be unshorted and intact. However, upon inspection of the test stand, there appears to be a ~100Ω load between the cathode and ground. This load is able to sustain voltage from the cathode power supply, but draws a significant amount of current. It is too much for operation, and might be further aggravated by the presence of the target. Further, when the TGHT and TBHT terminals are shorted together, the resistance from cathode to ground drops to ~1Ω. Perhaps this could be associated with the installation of the TGHT power supply, as FEBIAD has not been run on this machine since it was installed. Wiring at the feedthroughs as been quadruple checked, I don't believe that the problem lies there.
With no target in place, the cathode was able to hold a voltage, despite drawing 100+mA current. However, I was unable to repeat further tests, as the power supply stopped responding. Despite ramping up to ~10V in epics, the readback is 0V/0A, unlike before.
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