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.

Ta#37 has been moved from the south hot cell into the storage vault. The target is in pail #89 and in spot 6A in the vault. It was 840uSv/hr upon removal from the south hot cell. There are 7 free spots left in the vault.

West target station is setup to use argon for tank venting.  There is 1200 PSI remaining on argon bottle in electrical room.  That is sufficent for venting west target station to atmosphere twice.  ISAC Operations has been previousily contacted and their procedures for venting remain the same except that they can not rely on ITW:CG4S to determine when at atmospheric pressure.  I have asked them to contact me if an unscheduled vent is required.

Today a leak check on TM1's external seals and the heat shield line was completed by David Wang. After 16 hours of the turbo pumps running on the conditioning station stations pressures were 3.6 x 10^-6 T, 1.2 x 10^-5 T, and 1.8 x 10^-6 T for the containment box, secondary vacuum, and service cap respectively. This is a significantly quicker pump down after the cross with small turbo pump was installed on the vacuum vessel. The base pressure of the leak testing cart was 0.0 x 10^-4 T and the leak rate was 1.2 x 10 x 10^-8 atm cc / sec. There was no response from the external test where the module was sprayed with helium. The heat shield line was pressurized with 80 psi helium which caused the leak rate to climb to a maximum of 2.5 10 ^-8 atm cc / sec but dropped to 1.9 x 10^-8 atm cc / sec and was stable there, the total test time was 2 minutes. This test was repeated another time and had similar results.  These results although showing a slight increase in the detected leak rate are withing acceptable and indicate that the module is leak tight. 

At 9:30 the HV check and conditioning started (~17 hours turbos on), the secondary vacuum, containment box and service cap had the following pressures in Torr respectively, 1.0 x 10^-5, 3.2 x 10^-6, 1.6 x 10^-6.  The voltage was steadily raised with virtually no current up to 28.5 kV which was achieved at 9:50. When raised to 30 kV the current increased significantly to ~300 uA and a large amount of sparking occurred. The voltage was dropped to 0 volts for 2 minutes and then was returned to 30 kV at 10:03, the current draw was around 200 uA and climbing. After a few sparks and time the current had dropped to 120 uA. This indicates that the module is still conditioning and matches what is observed by the control room when the module is in ITW. The module was deemed acceptable for this current run and was then vented with argon this took about 2 hours.

The module was then remotely moved from the conditioning station to ITW. When first attempting to transfer the controls to the remote control room they were not transferred and when testing the up command as per standard procedure the module dropped down slightly. David Wang went to lock out the target again and the controls were successfully transferred. A note of this was made in the log book. Apart from this the move went smoothly.  

 On August 22nd TM1 was vented with Argon in the conditioning station. It had been pumping with just the roughing pump over the weekend so the UCx#2 target would not be exposed to oxygen. The move went without incident and took roughly an hour to complete. Once at the hot cell the panel was removed by Tom Lyth and a leak check completed with Bevan, David Wong, Grant Minor, and Tom Lyth present. The connections to source tray were checked starting at the top. Each connection was checked on either side of the VCR and at the center through the hole in the nut. For both connections on the source tray there was no response from the leak cart which was at a pressure of 0.0 x 10^-4 T and had a baseline leak rate of 0.0 x 10^-9 atm cc / sec. The leak check then proceeded to VCR connections on the Target. A leak was found on the upper VCR connection of the target and was repeatable. This leak was detected at the hole of the VCR nut connection by priming the line with helium and placing it next to the hole in the VCR connection. Response time was between 5 and 10 seconds to a maximum of 2.6 x 10^-8 atm cc / sec. The lower connection also appeared to have a small leak rate of 4.4 x 10^-9 atm cc/ sec but could be a result of helium drift. Unfortunately the target is not design to be repaired with manipulators and required the target to be removed from the south hot cell and repaired in the anteroom. The anteroom was prepared for the target by lining much of it with plastic so to prevent the spread of contamination. Once the target was in the anteroom it was leak checked again, the base pressure was 0.0 x 10^-4 and the base leak rate was 0.0 x 10^-9. A response from the upper connection again was detected in the 10^-8 range but no leak was found in the lower connection. It was attempted to tighten the joint to stop the leak but this caused it to increase to the 10^-7 range. This increase in leak rate is as expected from past experience because copper gaskets are used rather than silver plated ones. The heat shield cover was loosened and the gaskets from from both joints were replaced with the silver plated ones. The target was then leak check and passed with no response once again with a full pump down. The target was had an electrical checked with the megger and was within spec. The target was then placed in an argon bag and returned to the hot cell. The bag was damaged went placing it in the hot cell and there were not any acceptable options for leaving the target over night. The target was removed and and placed in 2 bags filled with argon for over night.

On August 23rd the target was removed from the argon bags that were still inflated and returned to the hot cell. The target was re-installed on the target module by Grant Minor, Tom Lyth, an Bevan Moss. One VCR gasket fell off during the first attempt and it appeared that the right target leg may have been slightly bent at some point. Other than that the installation went smoothly but slowly. The heat shield line was then leak checked once again by Grant, Tom, David, and Bevan and no response was detected from the source tray or target VCR connections, the base leak rate and pressure once again achieved the minimum detectable levels. The target module passed the electrical check with the megger, this test was completed by Bevan and Pierre Bricault. The module was then moved from the south hot cell to the conditioning station. Roughing was started at 3:00 and the turbo pumps were turned on at 3:45. The module was left to pump over night.