The silicon carbide targets voltage was raised to 42 kV today before continuous current draw was observed. It took roughly 10 minutes to raise the module to this voltage with only the occasional spark. The ION gauge reading was 2.0 x 10^-6 T, The service cap IMG 3.6 x 10^-6 T, and the secondary vacuum was 4.5 x 10^-6 T. Setup check and conditioning was performed by Pierre.

 I did a leak check again on TM4 today. This time, the leak detector pump to the bottom on both base pressure(0.0xE-4 torr) and base leak rate(0.0xE-9 atm.cc/sec). All high vacuum gauges on TM4 and conditioning station at -6torr range.IG1 is 3.3-6torr,PNG5(top of service cap)is 6.5-6 torr, and the PNG4(bottom of the vessel )is 8.7-6torr. For air to vacuum leak checking, I checked the panel we moved last week on service cap by spraying helium around the panel. There is no any response on leak detector. The panel is leak tight. Also I sprayed helium around the tube heater (+) water cap and blue nylon stand. They are also leak tight. Then, I put 80 psi pressure air to the “D” circuit first. With 80 psi pressure air for 5 minutes, the leak detector has no any response on it. Also all high vacuum gauges stayed at same level .Then I checked it with 80 psi pressure helium for 3 minutes. The leak detector has a response on leak rate with pressure helium same as last time. It climbed from the 0.0xE-9 atm. cc/sec quickly to high -8 range then slow down. The leak rate finally climbed to 2.0 X E-7 atm.cc/sec this time. There is no base pressure change on leak detector. All high vacuum gauge readings no change during the test time. There is a small helium leak at 80 psi pressure test on “D” circuit. But we can not locate it at this stage. Also I don’t want to disturb this circuit any more before the febiad run since this time I saw a little bit increase on leak rate comparing to last time when I checked it. If we really like to find this small helium leak, I would suggest we do it after the febiad run.    Thank you.

TM#4 with SiC#26 HP moved from the south hot cell to the conditioning station.

 After Chad and Davids leak check results from the containment box it was decided to perform a leak check on the feed through stem in the service cap. This is a known point of failure on TM1 and the same design flaw is likely in TM4. Once the service cap was open a visual inspection was performed and some oxidization of the copper line on the tube heater (+) circuit was observed (see attached pictures). The leak check was performed with the cart at a base pressure of 0.0 x 10^-4 Torr and base leak rate of 0.0 10 x 10^-9 atm cc/sec. A total of 4 joints were checked and no response was found. The service cap was then flooded with helium and once again no response was found. It was decided to give the module a clean bill of health, make note of the baseline test from the conditioning station, and continue to monitor the circuit.  

A leak check was performed on the module on October 27/10/2011 by David Wang and was reported to Bevan Moss but it never made it into the Elog system. This entry is to summarize the results of that testing. All circuits were pressurized to 80 psi with helium and every line except the tube heater (+) showed no or small responses as experienced before. The tube heater line had a slightly larger response under the conditions summarized below:

Varian 959

Base Pressure                   7.0 x 10^-3 Torr

Base Leak Rate                  7.5 x 10^-9 atm cc/sec

Gauges

IG1                                         2.0 x 10^-6 Torr

PNG5                                    9.6 x 10^-6 Torr

PNG4 (C.S.)                        2.4 x 10^-5 Torr

Convectron (Back line) 20mTorr

 The leak rate quickly climbed to 3.0 x 10^-8 atm cc/sec then constantly climbed to 1.4 x 10^-7 atm cc/sec for 2 minutes. David repeated this test again at the end of the leak test and found the same results. In the past we have called this a leak and attempted to find its location and repair it. David believes that this isn’t a real leak as we have been able to achieve very good vacuum on TM4 all year and that we do not normally touch the feed through stem on this circuit. This result makes me nervous as the total differential is roughly the same as that we found on the UCx#2 run(which was at a higher vacuum).

The result of this test caused the module to move back to the hot cell for further more localized leak checking.

HP febiad target SiC#26 was installed onto Tm4 on Monday morning.

"JP's" connector required lossing of the two mounting fasteners. Connector was pushed tight to its mating half on the source tray and both fasteners retightened, and the mating checked; it was good.

Two new 7/8 long 3/8-16 fasteners were used for the febiad coil connections.

Installation went well.

Leak check was performed:

Base Pressure: 0.0x10-4

Stable leak rate 0.0x10-9

Left vcr joint was checked two times with a 2 second spray of helium with a 60 second waiting time between sprays; no response.

Right vcr joint was checked two times with a 2 second spray of helium with a 60 second waiting time between sprays; no response.

Fllod of system with a 6 second spray; no response.

Base Pressure: 0.0x10-4

Stable Leak Rate: 0.0x10-9

Leak check of tube heater circuit, containment box side was performed.

Initail check at tube heater block on source tray yeilded a response 60 sec after the 2 second spray of helium. The response was very small and recovered immediately.

This area was checked twice more but the reponse could not be recreated.

Joint at the waterblocks was tested with an intial 2 sec spray. No response after 60 sec.

Waterblock joint was tested again with a 4 second spray. No response after 60 sec.

TM#4 moved from conditioning station to south hot cell. For further leak checking.

Roughing on TM1 started at ~15:00 today by ~16:30 the module had reached a pressure of ~200 mTorr and the turbo pumps were turned on. TP1 failed to achieve normal operation and we running at approximately 4KRPM and 50W with 6.1 A of current draw. TP2 was able to achieve normal operation. The controller for TP1 was then powered off and back on but that failed to resolve the issue. The controllers for TP1 & 2 were then switched at which point TP1 again failed normal operation and TP2 achieved it, thus eliminating the controller as the issue. The turbo pumps have been turned off and the roughing pump left on for overnight in case Vacuum group wishes to do any additional diagnosis. 

TM#4 with SiC#26 HP has been moved from the south hot cell to the conditioning station.

TM#4 with SiC#26 HP has been checked electrically it has passed. It was noted that the Megger check of the Oven to Chassis (earth ground) and Oven to 60kV Common is low but will not hinder running, according to Don Jackson.  Also yesterday the transition piece that sits on the 55 pin connector was damaged from excessive handling, it was removed and repaired and it now back in place.

The spent UCx #2 target has been moved into storage. It was placed in tray 5A and is in Pail #91, it was 8.91mSv/hr upon removal from the south hot cell. There are 5 free slots left in the storage vault.

Move of TM#1 with the TaC#1 target has been moved from the south hot cell to the west target station.

TM#1 with TaC#1 installed passed the electrical test. With a value of 882MOhms that was meggered from the heat shield to the chassis, all other measurements are within spec.

UCx#2 has been removed from Tm1 and put in a bucket with a slow argon feed and a lid placed lossely on top.

TaC#1 ITW has been installed and is awaiting testing at the cell.

TM#1 with UCx#2 has been moved from the west station to the south hot cell. Move went well.

The spent Ta#36 has been moved to the storage vault. It was placed in pail #90, and placed into slot 3B, it was 111mSv/hr upon removal from the south hot cell. There are 6 free slots left in the storage vault.

TM#4 moved from South Hot Cell to to North East Silo, move went well.

Ta#36 was removed from target module 4.

The standard, unexplained, un-investegated, un-resolved "arc" were again present on "JP's connector", otherwise no apparent problems visible.

Chad

Move of TM#4 with Ta#36 from East target station to south hot cell, move went well.