Repair of the west side hot cell manipulator was completed and the manipulator was re-installed into the hot cell.  No contamination was found in the lab, on the manipulator support frame, or on any tools.  A 'y' motion lock was also installed on the east manipulator and all accessible pulleys and rollers were lubricated.

 While leak checking components in the M20 front end on May 25th, the top of the T2 monolith was also checked by flooding the top of the monolith with helium while it was covered with plastic sheeting.  There was no response on the Varian leak detector indicating no significant leaks from the flange seals, shaft seals, and seals for upper services on the T2 target, T2 protect monitor, M9BB, M20BB, and M8BB/Col.A

 A tape snapped on the west side manipulator today while working on the T1-MK2 target repair.  The tape travels through to the slave end, so unfortunately the manipulator will need to be removed from the hot cell for repair.  This is the same manipulator that was just out for a broken cable repair, and I suspect that the tape was accidentally kinked or dislodged from a pulley when the manipulator was disassembled.

 The broken tape on the west side hot cell manipulator was found to be one of two "Z motion slave tapes".  The manipulator can still function normally with only one, however the remaining tape will see twice the load as usual.  It was decided that repair of the manipulator may be delayed until after the T1-MK2 target repair job is complete.  Lifting of heavy objects using the west side manipulator will be avoided until after the broken tape is replaced.

 A leak check was performed on the T1-MK2 target in the hot cell today and confirmed successful leak-free installation of the new water supply tubes, delta seal retaining rings, and delta seals on the upper slide plate.  The remaining tasks are to install delta seals on the lower slide plate and have the protect monitor and profile monitor electronics checked by diagnostics group.

 Bill Rawnsley and Mike Russell performed a 'blip' test on the T1-MK2 profile monitor and protect monitors today.  A possible bad wire at  #9 location in the vertical array on the profile monitor was found (this is two wires above center).  Bill did not think this was a serious concern and beam tuning can be (and has been done in the past) with wires missing.  Otherwise the responses were normal for both monitors and the scope readings were almost identical to when this target was checked in August 2011.

A full rebuild of the upper air amplifier was completed.  New anodized aluminum barrels were installed (replacing the old brass design), as well as new pilot valves, piston seals, bearings, and o-rings.  

The amplifier is operating smoothly with a cycle period of 25.6 seconds, compared to 14.8s before rebuild (based on 8 cycle measurents at 110psi output with beam blockers lowered).  

The lower air amplifier currently has a cycle period of 24.8 seconds under the same conditions (rebuilt in 2010).

 Repair of the west side hot cell manipulator was completed and the manipulator was re-installed into the cell.  The z-motion slave tapes, upper counterweight tapes, and lower counterweight tapes were replaced on both sides.

100cpm contamination was found on the slave arm from a wet wipe.  No contamination was found in the lab.

The T2 plug block was replaced and the M9 and M20 beam blockers were tested.  The plug block did not interfere with the travel of the beam blockers.  There was no change in the T2 vacuum during BB actuation.

Initially there was some confusion about how to actuate the beam blockers.  The following was learned:

M9BB:
- The M9 beam blocker is no longer part of a safety system because there are separate blockers for the M9A and M9B channels
- The M9 beam blocker does not need to be 'enabled' before actuation
- The M9 beam blocker can be actuated from the M9B ASU panel located on the B2 level
- The M9 beam blocker cannot be actuated from the control room.

M20BB:
- There are no additional blockers in the M20 beam line, so the M20BB functions as a safety system and must be lowered before the M20 area can be accessed
- The M20BB must be 'enabled' by controls before it can be actuated
- The M20BB can be actuated from the control room or the M20 ASU on the B2 level

 Target elevation measurements and beam spot plots were completed on the T1-MK2 target and the target is now fully repaired and ready for use.  It will be returned to the storage pit when cranes are available.

A copy of the elevations measurements and beam spot plots is attached.

 - T1 & T2 targets switched to "remote" control
 - Both target ladders were moved to Position 3 (12mm Be)
 - T2 Q1 flow interlock defeat was removed (only required when target ladder is in position zero)
 - The targets are now ready for BL1A start-up (up to 10μA this evening)
 

 BL1A was started yesterday and brought up to 10μA.  A problem was noticed with the T1 protect monitor (the right and bottom plates were not showing any response when the beam was swept across the monitor).  The protect monitor is new and was installed on the target assembly in February 2012, so this is the first time it has seen beam.  A 'blip' test was performed on the monitor in the hot cell and once again from the mezzanine after the target had been installed in the beam line.  Both tests showed that the monitor was performing normally, so an internal wiring mistake on the monitor was initially suspected and it was decided that the T1-MK1 target should be swapped with the T1-MK2 target.

Today the T1 monolith was uncovered, the T1-MK1 target was moved to the storage pit, and the T1-MK2 target was moved from the hot cell to the beam line.  The T1 volume pumped down normally after installation and a 'blip' test performed from the mezzanine showed that the protect monitor on the new target was functioning normally.  The potentiometer look-up tables were switched to the appropriate target (initially Graham Waters had difficulty with the control software, but was able to solve the problem by accessing the program remotely).  The T1 target is now ready for BL1A start-up.

This afternoon Bill Rawnsley discovered that there were two different protect monitor designs, one with a different internal wiring configuration than what has been used in the past.  If the protect monitor on the T1-MK1 target is the design with the different configuration, this could explain the symptoms observed yesterday.  If we had known this earlier, it may have been possible to solve the problem by installing a simple wire adapter at the mezzanine to switch the wires in the connector to the same configuration as the original design and the target swap would not have been necessary (saving time, dose, and the potential for damaging equipment due to handling).  This will be investigated further to determine if it is really the case.

 Installation of the seismic restraint clamps has been completed for the MK1 and MK2 target flasks in the Remote Handling lab (photos attached).  Two clamps on the MK1 flask required 3/8" shims due to warpage of the flask baseplate (see photo IMG_0429).

Dragan Mitrovic has been notified so that he can inspect the installation and close the work request.

- T1MK1 target transferred from storage pit to hot cell (max field: 4700 μSv/hr @ 0.5m)

- Protect monitor with incorrect wiring removed (20μSv/hr on contact, 60cpm contamination on 44-2 meter)

- Scott Kellog fixed the wiring and returned the protect monitor (correct wiring schematic is TDE0301E, previously used incorrect schematic D10649)

- Installed new protect monitor on target

- Profile monitor was found to have broken wires and will be replaced with new more robust design (0.005" thick gold coated molybdenum wires)

- Bill Rawnsley confirmed that protect and profile monitor wiring harnesses are wired correctly using resistor packs

- Bill was double-checking the wiring of the new profile monitor before installation and found that it had been wired incorrectly.  Scott K. will fix the wiring and return the monitor mid next week for installation.

- Leak check was performed on the target and confirmed that all seals and target cassettes are leak tight

- Re-wired profile monitor was received from Probes Group and installed on the target

- Protect and profile monitors were 'blip' tested, both OK

- Profile monitor actuation and limit switches tested, all OK (monitor starts to travel @ 20psi, fully engaged at ~40psi)

- Elevation measurements taken for profile and protect monitors

- Target ladder moved to position 3 (12mm Be target)

- Noticed strange 'click/twang' noise when moving target ladder, found to be caused by twisted bellows on water supply tube

- Bellows was straightened, and the target was leak checked again (still leak tight)

- Noticeable wear was found on potentiometer wires.  Pot values still read accurately.  Travis C. inspected and does not think they need urgent replacement.  Will have Probes Group look at it next time the target is in the HC (they are very busy now).

- T1-MK1 target transported from HC to storage pit location #3  (ready for use in beam line)

- T2-MK1 target transported from storage pit to HC (max field: 97,000 μSv/hr @ 0.5m)

 - Profile monitor wiring harness checked by Bill Rawnsley using resistor pack --> OK

 - New profile monitor (0.005" gold coated molybdenum wires) installed & blip tested --> OK

 - Potentiometer checked --> OK

 - Target position and profile monitor in/out micro-switches checked --> All OK

 - Target leak checked:  very small response at top and base of left side bellows (when facing target ladder), otherwise leak tight
         (Meter on 10X scale, Baseline: 6.  Meter reached 9 at top of bellows, 11 at bottom of bellows with 1s He application.  Both recovered after ~30s)

 - Straightened twisted bellows on both sides which was causing "clicking" noises during target ladder travel
      (Note: water supply tube nylon swagelok ferrules should be replaced at next opportunity, currently no spare parts)

 - Target leak checked again - No change due to bellows adjustment

 - Static water pressure test performed, as target is likely water leak tight: Target filled with water, pressurized with air to 80psi, then valved off and left overnight.  No visible water leak from bellows.  Pressure dropped 11psi over 15 hours.  Test was repeated, but the line valved off before the target to establish a baseline.    The baseline test dropped 15psi over 16 hours.  The increased leak is likely due to the additional valve added to the system, or different amounts of air in the system compared to total system volume.  Baseline test shows that the pressure drop seen in first test appears to be due to a small leak in the test equipment, or expansion over time of the supply water hose.  Concluded that target is water leak tight.  Additionally, target assemblies have been installed in the beam line in the past with significantly higher helium leak rates, and no observed water leak, with no problems.  

 - All water pumped from target using liquid nitrogen trap

 - Target ladder moved to position zero

 - Target moved from hot cell to storage pit location #4.  Ready for use in beam line.

 The "west" button on the crane pendant was broken, and the crane would occasionally continue moving west when the button was released.  The button was replaced by a Gordon Crane technician, who also did a crane inspection.  The hoist in the target flask is also due for an inspection, but it was not possible to do it this visit.  Neil Wong will try to have it done next time a crane technician is in.

 - The target control software was modified to reference the correct pot. look-up table for the target at T1 (T1-MK1)
 - The target position buttons on the T1 & T2 panels were not working properly and Graham Waters was contacted to investigate
 - Graham power cycled the microprocessor and the TG1 crate which seemed to make things worse (the control software would not even boot up)
 - Graham was able to diagnose the problem remotely, and found a loose cable which was causing it not to boot
 - The target position issue will not be looked into further until a longer maintenance period or the 2013 shutdown
 - Target position can be controlled manually using a portable control box
 - Using the control box, the T1 ladder was moved to position zero to allow use of the profile monitor;  The ladder was then moved back to position 3
 

  After removal of the leaky target cassette at position 3, plugs were installed on the target ladder and a leak check was performed.  With the target pumped down to approximately 10 mTorr, and helium detector gauge baseline of 9 on the 10X scale, a response of up to 25 on the 500X scale was observed when leak checking the right side delta seal on the lower face of the upper slide plate using a standard 1s spray of helium at 3 psi.  The flange screws were tightened and the leak check repeated.  Under the same conditions there was a response of up to 60 on the 100X scale - There was still a leak, but not as severe as before.  The screws were tightened further, and the target leak checked again, with no change.

At time of installation a response of  up to 10 on the 100X scale was found at the same location.  This target was found to be water leak tight and was used in  the beam line for ~4 months.  It is possible that the seal is still water leak tight.

The seal must be replaced or a static water test performed to show that the target is water leak tight.  Seal replacement will take approximately 2-3 days. 

The target ladder was detached, old delta seals removed, sealing surfaces cleaned using scotchbrite pad and a dremel tool, and delta seals were installed on the lower face of the upper slide plate.  The target was leak checked and found to have no significant leaks (no response from 2s helium spray at previous leak location on upper slide plate).

The profile and protect monitor electronics were checked by Bill Rawnsley and appear to be functioning normally.

The T1-MK2 target is now ready for use in the beam line.