Final assembly and alignment of TM2 optics tray continued today. Front section is "aligned".

A few additional higher-resolution photos of the TM2 source tray with new spacer ITA6270, and bent copper ground line clip.

Also attached is a photo of a 3/8" copper line placed in between the loose ECR line and the Mounting Support Plate line, for dimensional reference.

Hello,

For reference, I have attached a list of all solder joints in the TM2 Source Tray, and the alloys used for the most recent build (as per ITA6144).   I have also provided data sheets for the alloys, and PDF copies of all the drawings calling out the joints.

Certanium 34 C (222 deg C melt point) was used for all low-temperature solder applications, except for the steel inserts in the water blocks.  Previous revisions of the Source Tray drawings called out a higher-temperature McMaster lead-based solder (304 deg C melt point).  The change to Certanium 34 C on the prints was made in Bevan's era, during the transitional update of the source tray drawings between the TM1 and TM3 source tray projects, just before I took over updating the drawing packages.  I believe Bevan made this change on general advice from Guy Stanford, who stated that Certanium 34 C is a much easier solder to work with and makes a more mechanically reliable joint.  However, the change really should have had more review and validation testing before being implemented.

This said, we now have a source tray that uses Certanium 34 C, and rework of every joint would set us back too far in the schedule to meet the deadline, so we will have to run with it as it is.

Of particular concern are the joints on the target oven and coil heating blocks, which are now using a lower temperature solder (222 deg C melt vs 304 deg C melt).  We have experienced a coil block failure on TM4 due to a failed solder joint, although the failure mode is not known for certain.  We also had two recent failures on the test stand of a coil joint soldered with Certanium 34 C, but this was due to an error in the connection of cooling water to the joints (i.e. the joints had no coolant flow and the solder melted... this is expected!).

Anders and I have performed independent thermal analysis on the joints due to the radiative and electric heating from the target, and have concluded that even with a lower temperature solder, there is a lot of margin, so the risk seems to be low.  This work will be published in a separate report to be circulated later.

Thank you and regards,

Grant

Don Jackson brought to my attention some potential HV minimum spark gap issues with the source tray cooling lines.  It appears:

- The gap between the Ground Electrode cooling lines (ground) and Heat Shield cooling lines (HV) does not meet the spec of 0.668" MIN called out on the print

- The gap between the Window cooling lines (ground) and the Mounting Support Plate cooling lines (HV) does not meet the spec of 0.668" MIN called out on the print.

A copy of the tube bending drawing is attached with the spec highlighted in green.

The 0.668" MIN gap spec came from a check I asked Mark Llagan to perform to find the minimum gap when he was preparing the model for the tube bending drawing.  This gap was approved Jan 28th, 2015 by Friedhelm Ames on ECO-3587.

The source tray with the tubes bent as it is currently has been tested to 55 kV at the test stand by Anders, see:
https://elog.triumf.ca/TIS/Test-Stand/447

I am away June 12th to June 24th on vacation inclusive.  Isaac Earle is in charge of Remote Handling in my absence.

I am delegating Don Jackson responsible for resolving this TM2 HV issue, collecting and documenting the approval to proceed from the T/IS group leader with the source tray as-is, or to try to re-work the cooling lines and delay the project.

The source tray is NOT to be installed in the Hot Cell until this issue has been resolved.

Regards,

Grant

-- 
Grant Minor, M.A.Sc., P.Eng.
TRIUMF Remote Handling Group Leader
Nuclear Engineer
4004 Wesbrook Mall, Vancouver
BC, Canada, V6T2A3
gminor@triumf.ca
(604) 222-7359(604) 222-7359
http://www.triumf.ca/profiles/4557

Nb#10 has been installed on TM2 . electrical and leak check on HS line are good. See attachment.

TM2 was moved from ITW to the Conditioning Station.

TM2 was moved with no target attached from the South Hot Cell to a silo.

TM2 was moved from ITW to the South Hot Cell with Ta#66 target.

TM2 was moved from ITE to South Hot Cell. Tantalum 58 target.

TM2 was moved from South Hot Cell to ITE. ZrC #8 target.

TM2 has been moved from the Conditioning Station to ITE with Ta#59 target.

TM2 was moved from the Conditioning Station to ITE, with SiC#38 target.

The MK4 optics tray prepared for TM2 (as per ITA6082) had an undersized bore for the banana plug, making insertion of the plug extremely difficult / impossible.

Reference stores parts were collected to check the fit:  male plug 3-4/01152 and female jack 1-6/1201.  The size of the female jack was checked with a #21 drill at .159".

The bore on the optics tray was drilled out dry using the #21 drill to the same depth as the original blind hole, by Maico and Dan McDonald.  Chips were carefully collected in a rag, and the hole was blown out with compressed air.

The fit was checked to be snug but possible, using the male plug and the Remote Handling ultem base (ref ITA6023).

Redlines and photos are attached.

conductor insulators itd0053 and 54 have been replaced on TM2. All fasteners (1/4-20 x 1 1/4 vented) torqued to 60 in lbs.

Broken insulators ITD0053 and ITD0054 have been uninstalled from TM2.

TM2 was moved and connected in ITW yesterday afternoon. After roughing down, ITW turbo pumps are started. ITW TP4 can not be started to full speed. ISAC ops kept it at low speed mode with less than 1.0A current draw on pump. ITW IG1s shows red as well. I will take a look on them today when beam is off.

  Chad and I did the helium spray leak check on TM2 GE and MSP water lines at SHC this morning. We confirmed the GE leak on water blocks. We can not found the MSP leak by using the helium spray since its leak rate in TCS is much smaller than GE leak.  The leak check process are as below:
Leak detector are calibrated before the check.
GE lines : Base leak rate 0.0 X E-9 atm.cc/sec, base pressure 0.0 XE-4 torr.
Chad sprayed 5 psi helium to GE lines soldering joints  for 5 second, no response on leak detector.
Chad sprayed 5 psi helium to GE lines water blocks( between blocks seal surface) for 5 seconds, Leak detector response to 8 XE-9 atm.cc/sec right away.
Chad sprayed  5 psi helium to GE lines soldering joints for 5 seconds again, No response on leak detector.
Chad sprayed 5 psi helium around the source tray and to vacuum duct for 5 seconds more, No response on leak detector.
MSP lines: Base leak rate 0.0X E-9 atm.cc/sec, base pressure 0.0 X E-4 torr.  Chad did same thing as he did on GE lines. no response on LD. Chad repeated the test and prolonged the spray time to 10 seconds, No response.
The conclusion: It is pretty clear we have a leak on GE line water blocks seal.  MSP lines leak could not be found by helium spray in SHC since it is a small leak.
 

TM2 has been helium pressure tested in ITW and TCS. They are both tested with 70psi helium, each circuit for 3minutes. 

The leak detector base leak rate: 0.0X E-9 atm.cc/sec, base pressure 0.0 xE-4 torr  for both ITW and TCS. The test results are:

 2016-11-24: Checked again and added result into this elog.  No essential change has been found. MSP still has the biggest leak rate. David

Spark between HV cover vertical mesh plate and HS 60KV  bias connecting clamp 90degree angle at 55 KV on TM2 top. HV cover is removed to test above  55KV. The spark triggered TH and SHC ventilation secondary alarm.

Starting HV tests on TM2 with 50uA of protons.

Tuesday, August 06, 2019, 03:37 : Ramping up 500V every 2mins or so, couple of sparks, then consistent sparks at 34kV. No vacuum response on IG1 for any sparks, even though the current spikes from around 40uA to 1300uA. Brought it down to 28kV to stop sparking. See a response on the EZL frequently.

Tuesday, August 06, 2019, 05:24 : Going above 30kV proves very difficult, lots of up and down, frequent sparks, still no vacuum response. Still seeing an EZL response.

Tuesday, August 06, 2019, 05:58 : Up to 31.5kV on bias, 1046V on EE and 15kV on EZL.

Tuesday, August 06, 2019, 06:50 : Controls are being sticky - not responding well.

Tuesday, August 06, 2019, 07:25 : Sat at 32 kV > 20mins with 2 sparks

Tuesday, August 06, 2019, 08:03 : lots of sparking at 36kV, went back down to 35kV. Current draw is 50uA.

Tuesday, August 06, 2019, 08:10 : lots of sparking after 9 mins at 35kV, had to turn it down to 34kV

Tuesday, August 06, 2019, 08:11 : Still sparking at 34, down to 33

Tuesday, August 06, 2019, 08:31 : At 33kV, sparked twice in 20mins and was going for another when the protons went off.

With protons off, the bias current dropped quickly from 66uA to 40uA and raising the bias to 40kV was not difficult.  Later bias up to 50kV. Still no conclusion on if the sparking was inside or outside of the vacuum. No vacuum response seems to indicate outside, however the influence of protons would indicate inside. To be investigated visually when TM2 comes to the HC.