The T1 and T2 targets were both moved from Position 0 to Position 4 at approximately 2:30am on Saturday October 10th using the portable control box.  Operations had tried to move the T1 target to position 4 using the old control system but for unknown reasons it would move to any position except position 4 and the portable control box had to be used.  The portable control box should continue to be used for T1 and T2 target moves until the new control system is installed in the 2016 shutdown.

The following work was performed on the T2-MK1 target.  The profile monitor and monitor cage on this target were damaged in January 2013, See E-Log #68

Oct 23:
- T2-MK1 target moved from storage pit hole #4 to the hot cell (field measurement was not possible because the pole monitor had issues
- Position 2 and 3 targets photographed (see attached)
- Position 3 target (10cm Be) removed.  This target had accumulated 11.5 months of beam time.  Maximum for T2 targets is 12 months according to new schedule.

Oct 26:
- Position 3 plugged
- Profile monitor cage inspected and photographed. The cage (TBP0106D) and aluminum frame (TBP0101C) were both noticeably damaged (see photos)
- Attempted to insert dummy cassette, went in smoothly
- Moved target ladder through all positions, moves smoothly, micro-switches ok, potentiometer ok
- Motor drive coupling inspected - no issues
- Actuated monitor in and out: traveled fairly smoothly, 40psi required to insert, 20psi to pull back out
- Dummy cassette removed, real replacement cassette inserted (went smoothly)
- Horizontal wires inspected w/ Nikon level, found to be crooked

Oct 27:
- Cassette frame nuts (TBP0108C-2) loosened and monitor frame adjusted until horizontal wires horizontal, nuts re-tightened and torqued
- Vertical and horizontal measurements of profile monitor position measured - All within 1-2mm of previous measurements in 2010
- Although some physical damage to frame is visible it still positions monitor in correct location and seems to be fully functional, therefore will use if electrical is ok

Oct 28:
- Electrical check performed on profile monitor by Mike Russell
- All 26 wires visible.  Screenshot of scope taken (see attached)
- Moved to position 5 to stretch bellows, and air left running through target overnight to dry

Oct 29:
- Cold trap filled with LN2, pumping with new leak detector started
- Test port at E-1 Torr range after 30s, E-2 after 1.5mins, E-3 range after 3mins, 0.0E-10 torrL/s leak rate after ~10mins, TP at <1.0E-3Torr after ~15mins
- Leak check performed with 3psi helium applied w/ ~0.5s bursts at all target locations, bellows, top of vac flange, and Hansen fittings
- Small leak found at left bellows lower weld (expect is negligible for water use), no response from all target locations (see attached scan of leak check notes), deemed water leak tight

Nov 3:
- Plumb bob measurements taken
- Vertical and horizontal measurements of Pos'n 2 target taken
- Target ladder moved to position 0, profile monitor secured in IN position to prevent damage during move

Nov 5:
- Target returned to storage pit hole #4
- Field of 53mSv/hr measured at ~0.3m (attempted 0.5m measurement, but was a little close)

The T2-MK1 target is now fully functional and ready for use.  The 10cm Be target in position 2 has not seen beam.

Note that the target window welds show some uneveness (see photos), but not expected to affect performance b/c leak tight.  The elevations sheet will be updated and filed in the T2 Binder in the Meson Hall HC Lab Office.

Isaac Earle has recently been managing the fabrication of some new Be target cassettes for the T1 / T2 Meson Hall target ladders (WO 41527).

The machine shop has outsourced the cassette tubes to an external shop for wire EDM cutting, as it produces a much more repeatable and consistent wall thickness without the need for delicate forming and welding.

However, the legacy end-cap design TBP1690 calls out a thin-wall formed frame to help brace the window in place and provide material to fusion weld the rim of the end cap to the cassette tube.  The legacy design frame is extremely thin compared to the tube wall thickness, and this mismatch is extremely difficult to EB weld reliably.  If a mistake is made, the entire EDM cassette tube is scrapped.

Bob Welbourn and the machine shop have come up with an improved design for the frame and window with slightly modified forming tools.

The window thickness .003" and tube wall thickness .010" remain the same.  The only change is to the thickness of the welding frame, which is now matched with the tube wall thickness (previously .003", now .010").

Photos of the old (right) and new (left) weld results are attached, as well as the new forming tools created by Bob Welbourn.

The shop is now able to make a confident and reliable weld for the end caps.

I am not sure that the increased frame thickness will have any affect on the beam entry into the target cassette, but my assumption is that this region is not critical.  Now, if the beam does enter that material at the edge of the cap / tube, and the temperature changes during operation, there will be a more secure weld there due to this design improvement.

The machine shop was waiting for the OK to finish welding the end caps into the frames using this new technique / design, and seeing as how the old option was likely to produce more leaking or scrap parts, I gave them the go-ahead to proceed.

Isaac will take care of the drawing and documentation updates when he returns from holiday.

Thanks and regards,

Grant

Fabrication of the T1/T2 beryllium target testing jig (TBP1721) was completed today by Dan MacDonald.  With a target installed across the test ports, the inside volume pressurized with air to 103psi, and both ball valves closed, there was no noticeable drop in pressure over a 16 hour period.  This result was deemed satisfactory for use of the jig for hydrostatic testing of new targets.

Manufacturing of a new batch of T1 and T2 beryllium targets has been completed.

The job was completed under Machine Shop Work Order #41527.  Eleven 12mm T1 targets (TBP1683) and seven 10cm T2 targets (TBP1691) were completed (exhausting all stock of the leftover EDM'd target housings).  The target window profiles (TBP1695) were laser cut at an outside shop for greater precision and to save time.  The target window assemblies were electron beam welded to the target housings (TBP1687 & TBP1692) by Bob Welbourn.  The remainder of the tube welds were completed by George Sun.  Assembly of the Swagelok fittings, target inspections, hydrostatic testing, and final helium leak checks as specified on the assembly drawings were performed by Isaac Earle.  In addition to these tests, one spare target housing was pressure tested to 275psi (the max pressure of the regulator of target jig TBP1721).  The target windows bulged at this pressure, but did not rupture.

The attached spreadsheet has details on target measurements and test results.  The target serial numbers (listed in the spreadsheet) have been engraved on the 90 degree elbow of each target on both the entrance and exit side.  Detailed photographs were taken of each target which are stored on Isaac Earle's hard drive (too large to attach).

If the 2015 target replacement plan is followed (See E-Log #168), these targets should last for at least 10 years.

The T2-MK2 target was transported from the beam line to the hot cell using the transfer flask.  The target was measured to be 120mSv/hr at 0.5m.  The steel shielding plug was installed in the T2 target hole to reduce upwards shine.

New beryllium target cassettes will be installed on the target ladder before it is returned to the beam line.

On April 11th the T2-MK2 target was flushed with water, then overnight with air at 5psi supply pressure.  The target ladder was in Position 0 for this procedure.

On April 12th the target was pumped using a cold trap and the Varian leak detector for approximately 2 hours.

On April 13th pumping was restarted and the leak detector reached 0.0E-10 Torr*L/s with < 1.0E-3 Torr test port pressure.  A general helium spray was performed with a small response to the mid 10^-9 range and quick recovery (this target was in use all of the 2015 running period w/o any vacuum issues).  Plugs were removed from Positions 1 & 2.  The swagelok threads on the ladder were cleaned with a wire brush then pressurized air.  The sealing surfaces were cleaned using Scotchbrite then blown with air.  Threads and sealing surfaces were inspected with the Nikon level: some minor thread imperfects on the threads and a few small pits on the sealing surfaces were observed.  New 10cm beryllium targets were installed (Position 1:  Target "OCT.06#3",  Position 2: Target "#201").  A leak check was performed using 0.5s bursts of helium at supply pressure 3psi.  Helium was applied at all target positions, delta seal locations, and along the length of both bellows.  No responses observed that were greater than the initial leak check performed before the plugs were removed, therefore the target was deemed water leak tight and ready for use.

On April 14th position measurements for both new targets were taken as per Document-50194, which will be included in the target info sheet to be delivered to Operations.

On April 15th the target was returned to the beamline.  All services were attached, the cooling package started, and vacuum pumped down normally.

Photographs of the Position 4 beam spots as well as the target ladder after new target installation are attached.

Mike Russell from Diagnostics Group has completed an electrical check on the T1 and T2 profile and protect monitors.  He reports that both profile monitors look fine.  The T1 protect monitor looks fine except for a weak or missing signal from the halo monitor.  The T2 protect monitor looks fine.

Note: The protect monitor on the T1-MK2 target was working without issue during the previous running period and was not removed from the beam line during the 2016 shutdown.  The cable for the T1 protect monitor was not disconnected during the 2016 shutdown.

The T2-MK2 target at Position 4 has been adjust to approximately +1.5mm offset.  This causes the ladder to be moved downwards, raising the beam spot location on the target window.  The potentiometer ratio at this offset is approximately 0.810 (> 0.8059 nominal ratio for position 4, and therefore closer to Position 5)

The purpose of the offset is to better center the beamspot on the target window.  Target window photographs showed the beam spot being slightly below center (See E-Log #197), and target ladder elevations taken in Spring 2016 showed the Position 4 target approximately 1.0mm above the profile monitor center.

MCR has been instructed to continue running with this offset, and a message with details on how to do so was posted to their Plone site.

 Position #4 on the T2-MK2 target has now reached the maximum beam time.  The target was moved to Position #1 at the nominal elevation.  This target should be used for the remainder of the 2016 running period.

 The following work was performed on the T1-MK2 target assembly during the September 2016 Mini-shutdown:

Monday Sept 26:
- Target moved from beamline to hot cell (28mSv/hr at 0.5m)
- Position 4 beam spot on entrance and exit windows photographed (attached)
- Target flushed with fresh water, positions 0, 4, and 5 blown out with air, then left overnight with air blowing through position 0 at 10psi supply
 

Tuesday Sept 27:
- Pumped on target water system using lab leak detector:  reached 1.0E-3 Torr and E-8 Torr*L/s range in < 5 mins
- Initial leak check performed: TPP < 1.0E-3 Torr, Base leak rate: Low E-9 range, 3psi helium supply, ~0.5s bursts
- Response up to 3.6E-6 at lower left side delta seal (when facing ladder), up to 4.9E-7 for lower right seal  (note: T1 area at good vacuum level prior to mini-shutdown),  All other positions no response, or response in low E-8 range (assumed drift or insignificant helium leak)
- Plugs at positions 1, 2, and 3 removed.  All threads inspected, brushed with wire brush, rinsed with acetone, and blown dry with compressed air
- New targets installed:  Serial #101 at Position 1, #102 at Position 2, and #103 at Position 3  (Position 1 threads significantly stiffer than others, but no major issue)
- Leak check repeated: similar response from all locations including all beryllium target windows  (concluded suitable for use in beamline)
 

Wednesday Sept 28:
- Profile monitor actuation checked in hot cell:  movement starts at 27psi, fully actuated at 48psi, limit switches functioned properly
- All target ladder micro-switches checked, ok
- Vertical and horizontal target position measurements taken using procedure in Document #50194  (PDF attached)
 

Thursday Sept 29:
- Target returned to beam line and all services connected
- Target info sheet and elevations delivered to Ops, XTPAGE 7L updated
- T1/T2 PLC information updated with new cassette information
 

Friday Sept 30:
- Vacuum pumped on the T1 volume.  Quickly 200mTorr (threshold for T1 Vac OK signal).  Edi reports pump-down slower than usual, will evaluate on Monday.
- T1 package started (no change in BL1A vacuum)
- Profile monitor actuation checked from control room (actuated normally)
- T1 profile monitor and protect monitors checked by Mike Russel and Victor Verzilov:  profile monitor normal, protect monitor signals low but Victor expects it is fine and give ok to cover

 

 The T2-MK2 target assembly was moved from the beam line to the hot cell today.  A maximum field of 203mSv/hr was measured at approximately 0.5m

A steel shielding plug has been installed in the T2 hole to reduce shine and allow the T2 volume to be pumped down.

 The beam spot on the 10cm beryllium target in Position 1 on T2-MK2 (Target ID: "OCT.06#3") was measured and photographed yesterday.  A fairly well centered spot was measured to be approximately 4.6mm wide x 5.2mm tall on the entrance window and 5.7mm wide x 7.6mm tall on the exit window using the Nikon micrometer level.  This target first saw beam on June 16, 2016.

A PDF scan of the beam spot measurements and photographs of the beam spots are attached.

A strategy for alignment of the T2 protect monitor, T2 target, and T2 Collimator A was discussed today and decided upon by Yuri Bylinski, Isaac Earle, Yi-Nong Rao, and Roman Ruegg.  The purpose of the adjustment is to try to reduce the amount of beam lost as it passes through the T2 area (presumably being blocked by the collimator because it is not possible to steer the beam through all three devices in their current configuration).  Keeping in mind that changing the elevation of Collimator A would be prohibitively time consuming it was decided that the protect monitor and target both be adjusted upwards 3.0mm compared to where they were during the 2016 running period.  This will result in the following elevations (all w.r.t. the T2 target flange).  The T2 profile monitor elevation will also be adjusted to match the target elevation.  

T2 Protect Monitor:  1833.5mm (1833.2mm from protect monitor flange)

T2 Target: 1836.5mm 

T2 Collimator A:  1834.7mm  (1834.5mm from collimator flange;  This is the current collimator elevation, measurement taken by Tom Lyth in Feb 2009)

These values are similar to what were used in 2009 during which time TNF neutron flux rates were acceptable (>800), and centered beam spots were achieved.  During the 2016 running period the beam spot on target was also roughly centered.  At both times the target was approximately 3mm lower than the protect which seems to indicate the beam is travelling at a downwards angle, possibly not correctable with available tuning.  This is a departure from the strategy in the last few years when the target and protect monitor were adjusted downwards to bring them closer to the beam plane (they had risen due to movement of the T2 monolith).  This is now thought to have been a mistake because it made it difficult to steer beam through the collimator.

Beam will be started with T2 in Position 2 (new target, never seen beam), then after a few days the target assembly will be moved to the hot cell to check the beam spot to confirm alignment and make changes if the strategy needs adjusting.

A PDF copy of Yi-Nong's summary is also attached.

The following work was performed on the T2-MK2 target assembly and the T2 Protect assembly for maintenance purposes and to implement the alignment strategy detailed in E-Log #218:

March 30 (T2-MK2 target in hot cell):
- Profile monitor actuation checked:  moved in and out smoothly, fully in at ~25psi
- Ran through all target positions, motion smooth, micro-switches all ok, potentiometer value unsteady when moving between position 0-1, steady when stopped, no issues form positions 2-5 (this was also observed last shutdown and there were no issues with ladder moves in the 2016 running period using EPICS)
- Water system pumped out with cold trap for 2 hours (previously was purged with clean water, then air overnight)
- Leak check performed: 10 minutes to reach 5.0E-3 Torr TP pressure, 25 minutes to reach 1.0E-3 Torr; 3psi helium supply applied in 0.5s bursts;  No response at all target locations and all four aluminum delta seal locations.  At base of bellows on left side (when facing ladder) quick response up to 0.6E-8atm.cc/s, quick recovery to baseline (<10s); At base of bellows on right side (when facing ladder) quick response up to 1.2E-8atm.cc/s, quick recovery to baseline (<10s).  These small helium leaks were known (see E-Log #95) and have not caused issue in multiple years of running.
 

April 5:
- Position 1 and 2 potentiometer ratio changed to achieve new target alignment, look-up tables updated in PLC code (see E-Log #218, and attached new elevation measurements)
- Position 1 and 2 micro-switches adjusted to be centered at new positions
- Profile monitor inspected: no broken wires, but some not quite straight or parallel with others, also some wire insulation blackened.  Scott Kellogg recommended installing new profile cassette
- Old profile cassette removed in hot cell and new one installed
- Profile monitor elevation adjusted (see attached new elevation measurements)
 

April 6:
- Electrical check on profile monitor performed at HC by Dave Cameron: deemed OK
- T2-MK2 moved from the hot cell to the beam line (~200mSv/hr at 0.5m)
- T2 protect monitor moved from beam line to hot cell (~16mSv/hr at 0.5m)
 

April 7:
- Elevation of protect monitor measured to confirm old measurement: within 0.1mm
- Old protect monitor cassette removed
- New cassette supplied pre-adjusted by Scott Kellogg
- New cassette installed in HC, elevation measured on entrance side: 1832.8mm (intended elevation was 1833.2mm, from E-Log #218)
- Protect monitor electronics checked by Shengli Liu and Dave Cameron at the hot cell: all OK
 

April 10:
- T2 profile monitor cable plugged in which caused unexpected jump in vacuum: 20mTorr - 180mTorr
- Large nut at top of feed-through connector tightened and vacuum returned to baseline
- T2 target position 1 and 2 potentiometer values tested from EPICS system to confirm PLC look-up table changes ok
 

April 11:
- T2 Protect assembly returned to beamline (12mSv/hr at 0.5m).  T2 monolith position was monitored by Beamlines Group with their laser tracker during the move.  A maximum of 0.2mm movement was measured which is attributable to noise.
- Air amplifier started, leak found from one of the M20BB cylinders;  went away after reset of BB control system, BB exercised several times and leak could not be reproduced (no change to BL vacuum)
- T2 profile monitor tuned for slower actuation, smooth movement confirmed and no change to beamline vacuum (also done for T1 profile monitor)
- Electrical check on T2 protect monitor performed by Dave Cameron and Shengli Liu from racks on mezannine: all OK
- Electrical check on T2 profile monitor performed by Dave Cameron and Shengli Liu from racks on mezannine: initially very low signal, they discovered a previously unknown large resistor which was bypassed for the test:  approximately 1/2 of signals show response to HV blip, deemed OK to restore shielding
- Target info sheet and updated elevations measurements delivered to Operations (elevations sheet attached)

Note: the T1 target (T1-MK2) was not removed from the beamline this shutdown, so new elevation measurements have not been submitted and T1 profile and protect monitor checks have not been performed

 On May 5th the T2-MK2 target was moved to the hot cell for the purpose of checking the beam spot on the Position 2 beryllium target to confirm the results of the T2 area realignment detailed in E-logs #218 and #220.  In preparation beam was put on this target overnight for approximately 1.5hrs at 10uA and 4 hours at 50uA (previously had not seen beam).  Also, there had been issues with the T2 profile monitor over the last couple days, so inspection and repeat of electrical check in the hot cell was planned.  The field in the T2 monolith work area was up to 1.3mSv/hr, and a maximum field of 230mSv/hr was measured 0.5m from the target during removal.

Unfortunately no beam spot was visible on either the entrance or exit windows at Position 2  (a longer exposure will be required next time a beam spot is to be inspected).  Detailed photos were taken, one of each side attached.  It was noticed that the T2 profile monitor cassette had become dislodged within its housing (it was sitting approximately 1" from the fully installed position - photo attached).  It is suspected that this happened when the target assembly was in the beamline - the first time the profile monitor was exercised back in April it moved quite quickly which may have caused the cassette to come loose (it is only held in with friction of the 9-pin connectors and the fit of the cassette body in the housing).  It was re-inserted in the hot cell and an electrical check was performed by Shengli: all good.  After the target was returned to the beam line the electrical check was repeated while the monitor was actuated in and out: once again all good, and the movement of the monitor was slow and smooth (video taken)

Prior to this job new cameras were installed in the hot cell opening aimed at the support ring hole (one aimed north, the other east).  This proved to be a very useful upgrade and made the installation process significantly easier and smoother.  Two cameras were also used during target installation at the monolith (only 1 was used in the past).  Having a second camera at a different angle made alignment easier (reducing time and dose), and should be adopted for future target moves.

Vacuum pumpdown was normal, the cooling system was restarted without change to the vacuum, and operators were able to use the T2 profile monitor during beam ramp-up overnight.

Dose for this job:  Isaac 0.17mSv, Keith 0.06, Ron 0.06

 On Thursday May 11th operators attempted to move the T2 profile monitor (T2-MK2) to the IN position but were unsuccessful.  The monitor would leave the OUT limit, but would not reach the IN limit.  This was repeated 2 times. The air amplifier was inspected and nothing out of the ordinary was noted.  The T1 profile monitor was tested and was working properly.  At the time it was suspected that the monitor cassette had become dislodged as occurred earlier this running period (see E-Log #221).

Today monitor actuation was attempted again and it moved to the IN position normally, this was done a total of 3 times..  An electronic check was performed by Mike Russell who reported that it looked the same as when he last checked, meaning the monitor cassette was definitely not unplugged. The monitor was then used with beam and Eric Chapman reported that monitor was functioning normally.  With the beam spot centered vertically on the profile monitor the protect monitor showed more beam on the lower plate, which is expected because the protect monitor center is 2-3mm higher than the profile monitor center (see E-Log #220).

It is unknown why it would not actuate properly last week, but seems to be fine now.  Cyclotron fault #9928 has been returned.

The T2 heat exchanger secondary side solenoid failed on July 9 at approximately 19:30 (EPICS ID: B1A:T2CS:SVSEC).  The valve was replaced with a spare and the cooling package is now running normally.

The valve at this location also failed in November 2016:  https://elog.triumf.ca/TIS/RH-Meson+Hall/211  Further investigation will be attempted to determine if there is a root cause to the failure, or if it is a coincidence.

The attached OneNote PDF contains details of the work.  Cyclotron Fault #10119 has been returned.

 The #6 male Hansen fittings for the T1-MK1 and T2-MK1 targets (both currently stored in the target storage pit) were replaced today with new units.  Some of the target assembly Hansen fittings had shown signs of leaking and the internal seals are not easily replaced.

"120V" warning labels were put on the micro-switch IN and OUT limit sensors for the profile monitors on both targets.  These are the only micro-switches on the assemblies that still run at 120V after the PLC controls upgrade.

The following work was performed on the T2-MK2 target assembly during the 2017 fall shutdown:

Oct 4, 2017:
- Target moved from beamline to hot cell, measured 661mSv/hr at 0.5m (move went smoothly, having camera views at N/S and E/W angles very helpful)
- Flask tray wet wiped after transfer: 1st wipe 600cpm on 44-2 monitor, 2nd wipe 900cpm (3rd swipe not taken because tray looked clean)
- Flushed target with clean water, then compressed air (positions 0 through 5)
- Male Hansen fittings on the target assembly swapped with new units (in process of replacing all self sealing fittings in T1 and T2 water system)
- Checked all micro-switch positions and potentiometer readback: switches ok, pot value jumpy around position 1 and 2 (known from before), otherwise fine
- Left target overnight at position 4 with 20psi supply air running through to dry water system

Oct 5, 2017:
- Pumped down target with cold trap (~2 hours)
- Baseline leak check performed: 6 mins to reach 5.0E-3 Torr (3.2E-9 Torr*L/s), 21 mins to reach 1.0E-3 Torr (1.4E-10 Torr*L/s)
- Helium spray at 3psi for 0.5s bursts, tested with ladder in position 4
- No leak at any target positions or plugs
- Small leak on left side bellows, or bellows seal to ladder: up to 8.0E-9 Torr*L/s response, then quick recovery  (known from previous leak checks, same magnitude)
- Small leak on right side bellows, or bellows seal to ladder: up to 2.0E-8 Torr*L/s response, then quick recovery  (known from previous leak checks, same magnitude)
- Beam spot photos taken, position 1 (only target used this running period) has fairly well centered beam spot (see below)
- Position 4 target removed ("JAN29'97"), was very difficult to remove because one water tube stuck in ladder (this target was installed on ladder in 1997!  First beam 2014)
- Used hammer in hot cell to remove which eventually broke the target water tubes from the wire EDM housing
- sealing surfaces cleaned with burgandy Scotchbrite on electric dremel tool
- Inspected sealing surfaces and ladder fitting threads using Nikon level: all appeared clean and undamaged
- Installed new 12mm beryllium target at position 4 ("Jul.06#4"), no issues with install
- Leak check repeated: reached 1.0E-3 Torr after 3 minutes (1.3E-8Torr*L/s)
- Down to 3.5E-9 Torr*L/s after 18 mins, began test
- No response at all target positions, checked left side bellows: same response as above
- Beam spot profile at Position 1 measured with Nikon level
- Vertical and horizontal positions of new Position 4 target measured
- New profile monitor cassette retainer pin installed (plate hole had to be opened up to 0.375" diameter), used vice grip pliers clamped onto clevis pin in order to install

Oct 6, 2017:
- Profile monitor actuation tested: start movement 5psi, fully IN at 35psi
- Profile monitor limit switches tested, ok
- Target transported back to beamline, no issues
- BL1A pumped down, Edi reported pump-down normal
- Electrical check performed on T2 profile monitor from mezzannine: Sheng-Li reported results normal
- Cooling system started: no change to BL1A vacuum
- Target info sheet and target elevations sheet delivered to Main Ops
- XTPAGE 7L information updated