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

TM4 is moved from TCS to SW silo this morning. The move is good.

LD base leak rate, 0.0Xe-9atm.cc/sec. Helium pressure, 70psi. 5 minutes each circuit. No response on all water line except containment box window which has a VCR leak issue now. Window line leak rate, 2.3Xe-4 atm.cc/sec.

TM2 has been connected in ITE. turbo pumps have been started. ITE  and TM2 vacuum are good.

 Electrical of TM#2 with ZrC#8 at the south hot cell. See attached for details.

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

 Here are the results of the electrical done at the south hot cell post beam of with the Ta#58 target attached and with just the module no target attached.

TM2 has been disconnected in ITE. The bias jumper between U and T was burned out during the last beam time.

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

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.

TM4 has developed 4 leaks so far:

1. Line B - seems to be solved with an indium gasket (some testing already done)
2. Line D - seems to be solved with an indium gasket (some testing already done)
3. EE - indium gasket installed, preliminary tests are good
4. Window cooling line - David found with 70 psi helium, leak detector response went from 3E-7 atm.cc/sec to 4E-4torr atm.cc/sec in 1 min and stayed there. When water was put through the circuit, there was an initial vacuum increase to about 1E-6, then a couple hours later it began to fall and has been falling for ~14hrs, now in the 7E-7 range for IG1.

Testing indium seals on lines B, D, EE. No repair has been done for window line. Ramping heaters to TGHT=450A, TBHT=200A. Everything behaving normally.

Wednesday, ramped up BIAS, EZL and EE to 36kV, 17kV, 1.5kV. Sparking at about 1 spark per 20 - 30 mins. Bias current somewhere between 66uA and 78uA, varying with the chiller ON/OFF.

Thursday morning around 2am everything tripped off. No spark visible on strip tool, seems this is from an increase in the window water leak. Vacuum recovered on its own and heaters were ramped back up.

TM4 has been moved from the Conditioning Station to the South Hot Cell. No target.

Original Problem:

Leaks on the B and D copper blocks, probably due to corrosion between the blocks and the inserts. Final solution, after many tries, was to make an indium sheet the size of the copper blocks and use that to seal the entire surface.

So far offline tests seem to show these seals working, though long term tests are needed to say for sure.

New Problem:

TM4 was in the conditioning station, running water and under vacuum. 50A on the target and tube heaters from Friday evening to Saturday afternoon.

Sunday morning 9:30am target heating increased to 200A, 100A on the tube heater, ramp finishing around 1:30pm.

At around 3pm, the vacuum stops dropping and begins to climb very slowly, continuing until Monday morning (see first attachment).

Tests on the individual water lines show an immediate vacuum response only to the EE lines, the other lines show no response (note the window line is blanked off since the containment box is not on).

With water in the EE lines, the vacuum sits around 1e-6 near the target.

Testing:

Ramped target to 400A and tube to 200A. Sitting there for several hours shows no change in the vacuum response, though there is a variation that corresponds to the chiller turning on and off (see second attachment).

Ramped target to 450A and tube stayed at 200A. Vacuum staying in the low 10^-6 range, seems to be entirely due to EE leak, other seals are holding well.

 The SMP vacuum control system has been wired and setup to be controlled from EPICS.  Backing valve control (SMP:BV1) was tested by connecting to the turbo pump solenoid on TM3 located in the silo directly north of the SMP.  The SMP pump (SMP:MP1) was turned on and off through the EPICS interface and responded as expected.  Both convectron gauges (SMP:CG1 and SMP:CG2) responded as expected when the pump was turned on.  The readings from the two gauges were consistent throughout the mili-Torr range.

The work was done by Ray Mendoza under WP I2019-07-24-4 (work request #5239).

Electrical check on TM4 with spare test target. PQ is still shorted to RU. But, The short between 60KV bias and PQRU which we found last time is gone.  Target to PQRU at 250V mega measurement: 22.08 M. All conductivity between ABCD are about 5.0 m ohm which are good. All other ohm meter and Mega measurements are OL. Helium spray leak check on HS target VCR fittings is passed. Two blank offs are installed on source tray window cool lines. They passed  leak checked at SHC as well. 

Tm4 has been moved from SHc to TCS without containment box. It is a new source tray on TM4.  A layer of plastic sheet was put on TH floor on module pass route during the move.

TM4 has been moved from the South West silo to the South Hot Cell. New source tray, no target.

 TM4 has been moved from the conditioning station to the south west silo. Module was placed with the turbo pump facing south which puts the windows facing north and south and the shutter facing west. 

Yesterday, TM4 B line was supplied with water at TCS for testing.  TCS: IG1 and IG2 had big response on it. See attachment. The water was disconnected right away, and line was purged. Vacuum recovered after overnight pump.

David raised the bias to 49.5kV. Module is still sparking mainly on top. Humidity is super high.

Wednesday, July 10, 2019, 09:50 : sitting at 49.7kV for a coupe mins, big spark in vacuum took everything down.

Wednesday, July 10, 2019, 10:16 : Bias at 50kV drawing 0.1mA but looking pretty jumpy. Left it here for ~5 mins then had to turn down bias for TH work.

Wednesday, July 10, 2019, 13:33 : Back at 50kV on bias with no problems.

Wednesday, July 10, 2019, 13:46 : 10 mins at 50kV, will try to go a bit higher

Wednesday, July 10, 2019, 14:06 : Everything sparked off while sitting at 50.6kV. This seems a bit futile....

Wednesday, July 10, 2019, 14:15 : Back at 50.1kV with no problems

 Wednesday, July 10, 2019, 14:33 : Up to 51kV

Wednesday, July 10, 2019, 15:20 : Difficult to go above 51.4. Turning up EZL since there were a couple sparks to it. -> Putting this up causes significant sparks between HV bias and EZL in vacuum at 5kV on the EZL, 51.1kV on bias. Leaving EZL @ 5kV

Wednesday, July 10, 2019, 16:04 : Around 52.2 sparking on the top of the module

Wednesday, July 10, 2019, 16:36 : 53kV

Wednesday, July 10, 2019, 17:16 : up to 54kV without much trouble

Wednesday, July 10, 2019, 17:53 : Sitting at 55kV for about 4mins when a spark tripped off everything. Will try to bring it back to sit stable at 55kV tomorrow

Thursday, July 11, 2019, 10:28 : TM4 up to 54.9kV without too many problems, EZL at 25kV. Will sit here for a little while

Thursday, July 11, 2019, 10:48 : 20mins at 54.9kV, going to 55kV

Thursday, July 11, 2019, 11:14 : 25 mins at 55kV and everything sparked off

Thursday, July 11, 2019, 11:26 : Back up to BIAS / EZL = 54.8kV / 26kV. Checked that the TGHT and TBHT power supplies have not been killed by sparks, everything looks fine.

Thursday, July 11, 2019, 12:56 : Sat at 49.6kV for 1.5hrs with one spark.

Thursday, July 11, 2019, 14:02 : Been sitting at 55kV for 2 hrs now with one spark.

Friday, July 12, 2019, 08:09 : Back up to 52kV easily, then had to reduce step size to 100V to keep going

Friday, July 12, 2019, 08:47 : 56kV

everything sparked off at 56.5 or so