Tuesday, May 14, 2024, 10:26 :
Ramping up bias/EE/EL on ITE - will see if the HV cage in the pit can hold 60kV or not.
At around 50kV the bias read current starts to get jumpy. Doesn't look like its an issue for the voltage, but definitely instability increases.
Occasional sparks seem to increase the EL current significantly...
David heard some sparks in the target hall. Looks like from heat shield feed through to the top of the cage. Several sparks heard in the TH also changed the einzel lens draw current significantly. These feethroughs are not far from each other so could be related.
Apparently the sparking also tripped off all the optics and heaters in ITW, by changing the state of the water flow interlock. Interesting and not seen ever before. Will test again with the cage off, rather than risk tripping ITW again.
Tried ramping up the voltage on just the EE. Seems the limit is 7kV - at that level it gets sparky and unstable. Should be investigated (should hold 10kV) but not critical for module function.
Wednesday, May 15, 2024, 10:05 :
HV cover was removed this morning and the MAA was locked out.
Started ramping things up, was very easy until around 58kV. At 59.5kV a spark tripped off the EL. Canbus controller had to be power cycled to fix it. Bias current is much more stable in this configuration.
Ramped up again while listening from the TH to see if it was sparking outside. Went slowly to 60kV (left EL at 29kV) and didn't see any outside sparks in the first 10 mins, couple sparks in vacuum. But after 15 mins a spark seems to have fried the EL canbus card. We were not in the TH so not sure if it was on the outside or not.
After 2 hours a spark tripped off both ITE and ITW. Looks like it makes a water interlock go bad momentarily, but after the trip the interlocks seem fine.
Tuesday, May 28, 2024, 16:41
Running TM3 at any voltage in ITE produces fairly destructive sparks. There are not many but so far they have tripped off all optics in ITW, the water flow interlocks (later forced on to prevent this), the EL (generally comes back but killed the canbus card once), destroyed two vacuum gauge controllers, and may have contributed to the cathode short on ITE-TM3-UC44-LP-FEBIAD.
The conditioning process seems to go as planned, but the occassional inevitable spark still trips things, which is making it difficult to run stable.
Will continue with regular HV conditioning to see if this helps. Control over the current limit on the ITE:BIAS supply would also help, but seems a complicated thing to add according to Roberto.
TM3 sat fine at 53kV overnight and at 58kV for several hours. The EZL trips off maybe once every 2-3hrs or so, which is not ideal but liveable. This was with the TGHT and CHT power supplies forced, so not sure if we would know if they would have tripped...
CONCLUSIONS:
- TM3 has been commissioned for beam delivery after one week of delivery of UF to TITAN using a FEBIAD ion source in anode bias mode. Cathode mode was also used, so all functionality of the target except IGLIS current/voltage delivery through the mutlipin has been tested successfully.
- TM3 still requires commissioning at high voltage with protons to be considered fully commissioned, this will be done July 2 2024 due to problems with the cyclotron.
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