Ramped voltage on TM2 up to 30kV with no problems. Bias current is at 29uA, same as original TM2 bias current (see archiver for ITE June 15th, before protons) and similar to 31uA right after protons went off on Aug. 6.

TGHT=0A

TBHT=0A

BIAS V=30kV

BIAS current = 29uA

EZL V= 15kV

EZL current= 51uA

EE V= 1kV

EE current= 0.952mA

IG1= 8.6e-7

protons=0

This seems ok despite poor electrical checks showing 300 MOhm resistance between HV and ground. These values indicate a resistance of 1 GOhm. Let's see what happens when protons are on.

For future (optimistic) reference when testing protons:

BIAS=35kV, 35uA

EZL-17.5kV, 60uA

BIAS=38kV, 37uA

EZL=18.5kV, 63uA

Ramping up HV to ~30kV, encountered problems and had to drop back to 28kV. No response on IG1 or anything else during sparks. Lots of charging-type behaviour on the bias current. Protons at 55uA

Tuesday, September 17, 2019, 02:02 : 15 mins with only 1 spark at 30kV so increased the bias

Tuesday, September 17, 2019, 02:31 : 32kV. Current unstable

Tuesday, September 17, 2019, 02:41 : Current continues extremely unstable but not much sparking....

Tuesday, September 17, 2019, 02:53 : Proton beam trip initially settled the bias current down, but then current began climbing pretty steeply with protons still off

Tuesday, September 17, 2019, 03:28 : Protons dropped to 40uA from 55uA, Bias current is much more stable and no sparks for 25mins

Tuesday, September 17, 2019, 03:36 : Raising voltage easy to about 33.5kV then instability and sparking similar to around 31kV at 55uA p+

Tuesday, September 17, 2019, 04:45 : Lowered protons to 25uA and no sparks though the current is not stable

More things but forgot to write them down. Spreadsheet attached.

Tested RF from RF driver into new IGLIS wires at ITE. Used 5V, 1MHz (2MHz setting because of internal halving issue).

As expected there was a very slight mismatch visible (original cable ~ 68 Ohms, new cable ~ 53 Ohms).

The matching resistor will be changed and it will be retested.

Finally ITE:EL is still not working. It shows a value on the front of the PSU but doesn't draw enough current and doesn't affect the beam. We are running without it and it will hopefully be fixed on the Aug. 4 maintenance day.

These electrical issues bear some resemblance to those with Ta61, but I don't think we ever determined the cause there.

See the attached for the way ITE has been re-wired for the Ta62 run. Note also that the copper block in the schematic on TBHT negative may not actually be connected. Wiring verification on Aug. 4.

TM2 is in the TCS without containment box for HV testing following the installation of the IGLIS wiring.

Not great results so far - sat at 42.5kV for nearly 2 hours, current around 200uA and occasional sparks. I did not have time to go higher, will do this tomorrow. The sparks could be conditioning but it looks a bit suspicious to me. We will see if the ramp up tomorrow is very easy and how high we can go. I have data from HV testing of TM2 in December for comparison.

The EZL was reacting to all sparks, so I went into the target hall to see if it was sparking on the module top, but there was no sparking there.

Possible mitigations:

1. Re-do the connections on top of the service cap to remove the extra length on the wires inside the service cap and inspect the routing carefully to make sure nothing is in the wron place.
2. Inspect the wiring in the source tray to see if there is evidence of sparking in a certain area.

Second round of testing Tuesday April 5 2022:

Much better results, seems most of the sparking was conditioning. Went right up to 42.5kV with no issues. Spent quite a while getting up to 50kV, and didn't leave it there for more than a couple mins. May be running into the limitations of the HV cage at this point. Bias current was much lower, something like 140uA at 45kV.

Third round of testing Wednesday April 6 2022:

Ramped easily back to 45kV, a little more sparking above that. Sat at 47kV for ~30mins with no sparks. Won't try to go higher in case of issues with the cage. Will try to condition up to 50kV in the station. Other than the possible low megger value between B and C, all looks good.

Chad changed the EZL cable and plugs on TM2. New cable runs along the cable trays.

UCx#38 developed a short between the plasma electrode and the extraction electrode about 30mins after reaching full temperature in the conditioning station. The decision was made to bring it into the anteroom and try to clean it there.

To do this, it was uninstalled, the parasitic attachments were removed and it was brought into the ante room.

I removed the EE and the PE, and cleaned quite a lot of material from them both with methanol. I think put the ionizer foil bar down the ionizer to help dislodge any material there, and I also turned the target over and tapped gently to get any material out. The first two times some flakes came out, the third time nothing came out. I then reinstalled the electrodes using the EE alignment tool (not sure how successfully, didn't push it into the ionizer too much because I was worried about catching the Rh foil).

The taret was meggered at 500V then reinstalled and electrical checks were done. Everything looks back to normal. Conditioning in ITW was successful.

TM4 with SiC#44 installed developed a short TBHT to HV common during its first heating in ITE. Was fine before installation. Now with everything cold TBHT to HVC is 25kOhms. Removed short in electrical room, will rely on short in the module.

ITE:ANODE supply reading strange currents - 17mA with the power supply on and no voltage. Checked anode circuit from electrical room:

Anode wire in electrical room shows 0L at 250V

Circuit with 50kOhm resistor mostly looks good (49-52kOhms) but a couple times read 28kOhms, no idea why. Tried jiggling all cables, unplugging and replugging and everything looks fine.

But power supply still seems to be giving out signal for 17mA readback. Decided fastest to swap with TCS power supply and troubleshoot this one on the bench.

Conducted PIE on SiC#44, which failed online. It had a cathode short, a target short and an anode short by the time we called the experiment off. In the post irradiation examination, two clear marks where the target legs touched the heat shield were found (see attachments 1 and 2). No marks were found to indicate where the cathode short would have been. The fibreglass sheath covering the anode wire where it passes over top of the coil was destroyed, must have been a result of sparking (see attachment 3). No other issues noticed, grid looked fine, though close inspection is difficult.

During the last ITE run with the SiC#44 target, the ITE:TBHT controls card was fried twice. The first time we put in our spare, and the second time we just continued to run without controls readback. For the C#4 run starting Oct. 19, we used the conditioning station supply. As soon as one of the other supplies is fixed, we will install it in the conditioning station. The equipment list (https://triumfoffice365-my.sharepoint.com/:x:/g/personal/cbabcock_triumf_ca/EQPffP4p1P9JqEDWIHGRPfsBVDSQjMCv-M8ZNg4ngkyGHw?e=fnLVYe) tracks these movements.

Did the PIE on UCx#39-IGLIS on Thursday Nov. 2 2022, couple pictures uploaded to docushare. Did not remove the target, just the heat shield cover.

Final electrical check on the module showed a dead short from TGHT/TBHT to HV common, which we did not see online. Seems like it must have occurred after ramp down? It persisted on the target after we removed it from the module. We couldn't find any obvious contact points, because it seems it did not happen while current was running in the target. Possible locations are the bottom support leg for the TBHT and the top of the right side target leg, though it was difficult to confirm with the camera.

Otherwise the only thing to note was a blacker-than-usual spot on the inside of the Cu heat shield, downstream in the proton direction.

The pin on TM4 has become loose again, making it very difficult to remove the multipin connector with the last target, C#4. For the installation of the next target, UCx#41, we will drill out the hole on the target side bracket so that it doesn't contact the multipin pin. Will try to remove this pin by force in January, or if needed change out the whole multipin bracket.

Post irradiation inspection of C#4 which was running in TM4/ITE was conducted at the NHC on Nov. 22 2022.

The yields from this target had been dropping and its behaviour was erratic, with the voltages on the tube and target jumping all over the place sometimes. The ion current on the FCs followed the voltages. We took this to mean the target container was breaking down.

Upon inspection we found the container looked pretty damaged - highly crystallized and distorted. The container had gone banana-shaped, but not in the usual direction. It had curved  in the direction of the ion source (see photos). The heat shield and other surrounding components were super clean, no deposits or marks at all.

Feb. 16 2023: HV tests done on ITE station. Ramped up to 59kV but was not stable there, current draw was very unstable and was sparking every ~6mins. Ramped down to 58kV and it was stable there for 3 hours drawing 285uA.

Feb. 24 2023: HV tests done on ITW station. Ramped easily to 60kV with no sparking - suspicious. Has been stable at 60kV for 45mins with no sparks and current draw of 200uA. Cannot find any reason that things aren't connected properly...

On Sept. 14 2022, a 10kOhm 30W resistor was installed in each target station faraday cage, in line with the HV bias supply. This was an effort to reduce the current draw from the BIAS supply and protect the power supply controls cards which have been repeatedly breaking due to HV sparks (we think). In the end we still broke cards after the installation, so it doesn't seem to have helped. See below for details on the electrical side:

At 30kV, HV currents are around 100-150uA, meaning the voltage drop over the resistor is around 1.5V. When operating at higher voltages, with higher current draw, the voltage across the resistor could be over 2V and we could get into a situation where it would have an effect outside the normal adjustments needed on the mass separator. We made this decision based on the fact that the power supply's setting resolution is on the order of 1 x 10^-4.

When the resistance of the water changes, this affects the current draw from the power supply and this in turn affects the voltage over this resistor. Based on some sample numbers of running times, there is not much variation in the current except from sparks and if there is some issue, like water leaking between HV and ground. During normal running, the voltage change across the resistor should be less than 0.5V during normal operation. This is on the same order as the 8 hour stability of the power supply.

Yesterday and today module conditioning was done on Tm4 in ITE. This is the first ramp up after the shutdown and ITE is planned to run at high voltages for the first weeks. The module is behaving well - went up to 40kV yesterday, stayed there for an hour, and up to 46kV today. Current draw is 113uA at 46kV. No serious sparking.

Tuesday, May 23, 2023, 09:32 :  Ramping up again, easy to 45kV. Drawing 132uA at 49kV. Still behaving quite well.

When I tried to raise the anode voltage in cathode bias mode on May 23 evening, I found the target or tube shorted to HV common. Investigations in the faraday cage today showed the same. I removed all the new electronics (resistors, gemovs, etc) from the power supply to no effect, so I disconnected the TGHT supply and pushed it away from the busbars. There was still a short. David Frank and I then went down to the pit and disconnected everything to measure the module. The module itself showed no short, and the bus bars in the chase for TGHT showed no short, though the ones for TBHT still showed the short.

David and Frank reconnected the module and I disconnected the TBHT supply in the faraday cage, then I found no shorts to TGHT/TBHT. When I reconnected everything there were still no shorts. There must have been a short in the TBHT line in the faraday cage, and another short in the TGHT line in either the faraday cage or on the module top. Both these shorts got resolved by taking everything apart. Still not sure how it happened.

Next I found I could not raise the anode voltage above 230V, it looked like it was current limiting but since the current limit was high, I figured it had something to do with the new electronics installed. I disconnected them all the in cage and that solved the problem, and then reconnecting the gemovs that go from the PSU terminals to HV common caused the problem again, so I left those disconnected.

Conditioned TM2 up to 48kV in ITW. Some sparks and current is not very stable. Drawing about 178uA at 48kV.