On May 23, 2024 two sets of plugs from position 1 and 3 and a 12mm Be target from position 5 (serial #109) was removed from T1-MK1 in the Meson Hall remote handling hot cell.

The plugs and spent target are kept in the secondary hot cell (East) on the lift table for future beamspot imaging and to cool down prior to disposal.

In their place 12mm Be targets were placed:

• #107 in position 5
• #110 in position 3
• #111 in position 1

We will continue with leak checking and position measurements in the coming week, at which point this ELOG will be updated.

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UPDATE May 24:

• leak testing began on the T1-MK1, vacuum stagnated at 1.5e-2 Torr and a leak rate of 3.9e-07 atm-cc/sec (system vented, will re-tighten target fittings and re-do leak test). 
• after tightening and repeating pump-down in the afternoon, the vacuum volume stalled again at 1.5e-2 Torr. releasing helium to the target fittings registered a response in the leak tester at all virtually locations (for either side of the ladder). 
• the plan for the coming monday is to re-check the vacuum fittings and re-tighten the swage-lok connections to the targets before repeating the leak test once more.

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UPDATE May 27:

• the swage fittings for the targets on position 1,3,5 were tightened in the morning but the volume still couldn't be pumped down to 1e-03 Torr.
• pumping down only on the vacuum line (up to KF elbow ahead of hansen fitting at outlet of target connections pannel) allowed the pressure to drop to 1e-03 Torr so it was determined that the leak tester + associated vacuum connections were not the problem.
• shortly afterwards, we troubleshooted by pumping only to the 'high pressure test' setting (no Turbo pump) and sprayed helium to various joints above the target flange. we learned that there is likely some leaking through the hansen fittings + the swage elbow from the fittings down through the target flange.
• plastic ferrules are used in this elbow to allow for some seals to be replaced, so this may be the source of the leak.
• then, the fittings on the target ladder were re-tightened and helium was sprayed onto various fittings on the ladder. all but the left join on target ladder #1 (position 9a) does not register a leak rate above baseline after tightening.
• at end of day, the ladder was able to consistently reach a base-line leak rate of 1.7e-07 Torr-l/sec and a vacuum of 4e-3 Torr.
• we will proceed with replacing the water line connections on top of the target flange and re-check the leak-tightness of the ladder in the coming days.

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UPDATE June 14:

several attempts at replacing the plastic (Nylon, Swage NY-1013-1 and NY-1014-1) ferrules and re-establishing the fittings on the target service panel were made since the last update. it was determined that the lines leading from the leak detector to the target panel was leak tight (reached 1e-03 Torr within ~5 minutes of pumping down). a double-male Hansen adapter was made to test this (see image). in the final attempt to re-seal, the nylon ferrul-ed fittings were tightened last and the target managed to pump down to 2e-03 Torr, with a stable baseline leak rate of ~2e-08 Torr-L/s. note that prior to exchanging targets, the leak rate obtained during water flushing was 1e-10 Torr-L/sec. additionally, spraying helium on the inlet fittings still registered a response at the leak detector (~4e-6 Torr-L/sec in the worst case).

we think that the following happened to the target, leading to the leak: at some point the target panel collided with something by the water outlet hansen port (see image), this caused the nylon ferrule at that line to crack/become damaged but no leaks occurred immediately after. when we performed the target exchange, the water line was disturbed in some way either as a result of torque-ing the target fittings or when the ladder was moved on the turntable causing the joint to completely fail and leak. because of the damage from the collision, after taking the fittings apart, it is no longer possible to return the fittings and for them to seal.

the plan moving forward is to implement some minor design changes to 1) replace the damaged fittings on the target panel, 2) better facilitate replacement of the nylon ferrules in the future, 3) better facilitate leak testing on the target service panel connections.

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UPDATE Sep 27:

• After designing, releasing, and procuring the leak fix components (see TRH1681), we implemented changes to the electrical barrel connectors and tested the fit of the cooling line piping (see pictures).
• We checked that the ladder motor, potentiometer, and limit switch circuits all worked properly.
• Some differences were noted:
  • D10414-2 accepts 1/4"-20 screws to mount the panel, not 10-24 like shown in the legacy drawings, the clearance hole on TRH1682 had to be adjusted accordingly.
  • The low profile screws specified for the barrel connectors were difficult to use (item 108 in TRH1681), so instead we used normal 4-40 socket head cap screws and were able to check that the barrel connectors could fully couple without interference from the socket head.
  • We did not use lock washers for the barrel connector flanges because they drop too easily and instead we elected to tighten the nuts well.
  • Some loose leads fell out of the potentiometer (bottom left) and profile monitor (bottom right) barrel connectors. These were not electrically connected to anything so we decided to remove them, they will be kept in a recorded location at the end of the operation. 
• In the coming week, we will look to fasten the water line fully and check that they are leak tight.

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UPDATE Oct 02:

• The water line was fastened fully, some items noted:
  • Order of fittings tightened: elbow to bulkhead adapter > elbow to reducer > 5/8" connector to tube > elbow with reducer to tube > nylon ferrule connection
  • We tried to tighten the elbow with reducer to the tubes with the tubes in position to minimize loading the nylon ferrule at the end but found that the outlet tube still ended up protruding significantly from the bulkhead plate (see image). For future operations we should make a note to not load the outlet tube too significantly because it is only supported by the tube (bulkhead nut not fully engaged).
  • The above issue likely resulted from bending the tubes to the 3D printed template but yielding misaligned ends. In the future better templates that emphasize absolute end alignment for tube bending should be made
  • The NPT-Hansen nipple was not tightened before the water line was put on which may have applied unnecessary loads onto the tubes. In the future we will make a note in the drawing on which fittings to tighten first and how to perform the operation to minimize loading on the nylon ferrules
  • In the future some modifications can be made to help relieve this issue for version 2 of the water connections, maybe using flexible metal tubes or thinner walled pipe, alternatively we can implement a more flexible mounting approach for the Hansen ends.
• We noted some tight clearances on the electrical bulkhead. In future implementations of the fix, the connectors can be spaced farther apart or staggered, also they should be moved further down from the top flange of the target ladder.
• Leak testing proceeded with the following results:
  • Total time under vacuum ~2 hours
  • Reached 'fine' vacuum within 1 minute, pressure saturated to 2e-3 Torr within 3 mins 30 secs.
  • Baseline leak rate of 0.0e-10 Torr-L/s reached within 7 minutes of pumping down.
  • ~1.4e-9 Torr-L/s peak @ 15s delay (to first signal) after 1s x 3psi He to general vicinity of newly made water line connections << deemed acceptable
  • 0.5s x 3 psi bursts of He
    • ~0.9e-09 Torr-L/s peak @ 15s delay to nylon ferrule outlet line (did not change after further tightening) < deemed acceptable
    • ~0.2e-10 Torr-L/s peak @ 15s delay to nylon ferrule inlet line < deemed acceptable
    • ~0.5e-10 Torr-L/s peak @ 40s delay to NPT-Hansen outlet < deemed acceptable
    • ~0.4e-10 Torr-L/s peak @ 40s delay to NPT-Hansen inlet < deemed acceptable
  • SS swagelok connections not tested thoroughly due to low likelihood of being a leak source (all tightened properly to 1.25 turns as per swagelok directions)
  • He 'bleed' test by closing hot-cell He wand solenoid valve and bringing wand opening ~5 cm from pos.5 target swagelok resulted in a stable leak rate of 0.8e-8 Torr-L/s << target ladder leak likely prevents pressure in target ladder from bottoming out.
• Will carry on with leak testing the target ladder and possibly the swagelok fittings on top of the hot cell if necessary by the end of the week.

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UPDATE Oct 04:

• The target ladder was pumped down at ~11 am and reached the same baseline as yesterday (0e-10 Torr-L/s @ 2e-3 Torr within 3mins, 30 sec), but in the afternoon, the baseline leak rate worsened to 1.0e-8 Torr-L/s.
• For reference, 0.5s of 3psi He was delivered to the water outlet nylon ferrule joint and registered a response of 1.8e-8 Torr-L/s with a delay of 20 sec. A 3s spray at 3 psi around the water fittings registered a 4.9e-8 Torr-L/s response with a 15s delay.
• The following was observed from sending 0.5s of He to the target ladder Swagelok fittings (see Img for more details):
  • Leak rate baseline improved during testing (~over 1 hour) to 3.0e-9 Torr-L/s
  • Bellows, and targets 2-5 registered leak rates in the order of 1e-8 Torr-L/s
  • Target 1's left Swagelok fitting registered the highest leak rate at 2.8e-7 Torr-L/s (when the leak rate baseline would have dropped to the lowest value of 3.0e-9 Torr-L/s)
• We checked the KF and hansen fittings to make sure that they are not a leak source and managed to bottom out on both the leak rate and pressure readings on the leak tester.
• We will take off Target 1 in the next session, run a die over the male threads, clean the conical face of the male thread with scotchbrite,and attempt to re-do the target joint before leak testing once more.

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UPDATE Oct 11:

• We removed target at pos 1 (ID 111), noticing that the swagelok nuts were easy to undo.
• Working theories on how they became 'loose' include: 1) creep undoing misalignment between the two swagelok tubes on target, 2) vibration from the nuclear ventilation onto the target ladder undoing the joint, 3) thermal changes between summer and 'fall'.
• The threads on pos1 seem worn, it may be a good idea to plug this ladder position permanently to avoid further damaging the threads and jeopardizing the ladder in the future (see image).
• The ferrules on the target seem to be in good condition but we should still clean them with the scotch brite tool
• We added plugs over the exposed male swagelok ports to protect from debris entering the water line.
• We placed the removed target between two wypalls and weighed the wypall down with a wrench to protect it from debris.
• The 3D printed scotch brite tools need to be re-designed for 3/8" drive size (was designed for 1/2" drives).
• We will return to bag, and package the target for safe keeping in the secondary hot cell; clean the male swagelok threads and sealing faces on pos 1 target ladder; and possibly place permanent plugs in pos 1.

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UPDATE Oct 15:

• The leak tester was calibrated with an external calibrator. Original leak rate 1.3e-7 Torr-L/s, 2% loss over ~10 years >> ~1.1 Torr-L/s leak rate.
• The leak checker registered an initial leak rate of ~2.3 Torr-L/s before calibration so we corrected the measurement (at least within the calibration range) by a factor of 2.
• This voids old leak testing data that we made on the target ladder.
• We will add a note to the procedure to ensure that the leak detector has been calibrated before performing leak testing in the future

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UPDATE Oct 23:

• After some testing with 3/8" tube Swagelok threads outside of the hot cell, we determined that the reason the threads in pos 1 of the target ladder was 'difficult' to run was likely because the nuts were over-tightened previously.
• There is a risk of compromising the threads if we run the die over over-tightened threads because they have been shifted from where they should be. We will instead attempt to replace the plugs, after cleaning the sealing face on the male threads using the cleaning tools.
• We also checked with a Swagelok tightening gage (3/8) to see whether the other targets were tightened properly, and all had gaps smaller than the gage. Note that we could not get fully into the gap with the gage on the side by the profile/protect monitor due to interference with a support column with the gripper. We will make an extender tool to avoid this issue in the future.
• We also bagged the target that was previously mounted onto pos 1 on the ladder and moved it to the secondary hot cell for storage (temporary).

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UPDATE Oct 24:

• The threads and sealing face on pos 1 were cleaned with scotch brite, blown with compressed air from the inside by connecting compressed air line at the service panel, blown with compressed air from a bottle externally, and wiped with a wypall with the manipulators.
• The old plugs were moved to the secondary hot cell, new plugs were tightened onto pos 1.
• Initially the baseline leak rate was 3.3e-8 Torr-l/s at 4e-3 Torr. With He, we were able to determine that the plugs, specifically position 9a, was the most leaky joint in the ladder.
• After a couple rounds of tightening the plugs, and making sure that the remaining targets were also tight, the baseline improved to 1.7e-9 Torr-l/sec. The plug at position 9a also no longer registered a leak response from having the He line brought up to the joint.
• The plug at position 9a still is the leakiest location in the ladder however, registering a peak leak rate of 2e-8 Torr-l/s at the final baseline.
• We deem that the ladder is sufficiently leak tight, and we will move on to replacing a rubber coupling on top of the target ladder before performing target position measurements.

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UPDATE Nov 25:

• The coupler was successfully removed with a custom puller tool (see TRH1730, TRH1731, TRH1732, and Document-244878). This tool is used for the 3/8" shaft side.
• The press fit coupler had to be cut up with a dremel and saw before using the tool.
• The old coupler had to be 'cut-up' to be removed. During initial troubleshooting, the rubber body split, indicating that it was near end of life.
• The replacement coupler system could be inserted without removing any parts.
• The relative alignment of the shafts may have changed up to 1/2 a turn during this process (the printed clamps were not strong enough to resist torques exerted when attempting to remove the press fit coupler).
• Potentiometer table will need to be reviewed when performing target measurements.
• Light loctite to be added to the treads.
• Note: the old coupler has stainless shaft adapter (3/8" step down).

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UPDATE Nov 28:

• Loctite added to all coupler screws (including flexible coupling from motor to three-way gearbox)
• Final leak check completed on replacement piping on service panel with the following results
  • baseline leak rate bottomed to 0.0e-10 Torr-L/sec within 7 mins and pressure bottomed to 1e-3 Torr within 5 mins.
  • baseline leak rate worsened to around 1e-9 Torr-L/sec by the end of leak testing, assumed due to increase in amount of trapped He in the line through testing
  • (time to detect [s] || peak leak rate [Torr-L/sec]) values for 3psi, 0.5s Helium using wand on top of hot cell
    • inlet side:
      • 20s || 3.8e-10 for nylon ferrule joint
      • 20s || 6.3e-10 for o-ring flange
      • 20s || 2.7e-10 for hansen NPT thread
    • outlet side:
      • 15s || 3.5e-10 for plastic ferrule joint
      • 15s || 5.1e-10 for o-ring flange
      • 20s || 0.8e-9 for hansen NPT thread

The target ladder was moved to the lift table in preparation for measurements.

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UPDATE Jan 03, 2025:

• Measurements (elevations) of the targets and alignment jig were completed over December to early January.
• Notes on measurement procedure:
  • Used the old alignment jig instead of new (easier to insert/remove)
  • Noticed that the target ladder potentiometer is jumpy at around 12 kOhm
  • Placed the jig between positions 4-5 throughout (pot reading of 11.65 kOhm places the jig in beam height - in line with protect monitor)
  • For left-right measurements, moved the alignment jig 'into-position' (i.e. set potentiometer value to 11.65 kOhm) to 'zero' the micrometer before changing ladder position (potentiometer value) back to the target being measured (turntable height not touched after zero-ing off to the jig)
    • For the entry side, because the protect monitor is obstructing, target 5 had to be measured above the protect monitor (jig also zeroed off above the protect monitor, i.e. not at the resistance value given above), while all other targets were measured below.
    • This introduces some error since we are measuring the target not in the beam position.
  • Target height measurements were done with measuring tape as normal.
  • Targets were measured with turntable flange having an angle of ~0.2 degrees, plumb bob and jig measurements taken with turntable flange 'leveled' as best as possible (angle of ~0.02 degrees)
    • For future measurements, the turntable should be also leveled before target measurements.
  • Levelling the turntable flange was done with a Digi-pass digital level (DW-1300XY, in absolute level mode, calibrated before starting)
  • By the cutout, the turntable flange is less stiff, causing level measurements to be tilted inward. We therefore relied more on level measurements on solid portions of the turntable flange as well as on the target flange.
  • Levelling bolts could be turned with target ladder seated.
  • If the turntable is not rotated, and only raised/lowered, the levelness of the table and target remained approximately constant (e.g. from 0.02 degrees change to 0.04 degrees as the turntable is lowered fully from fully raised).
  • If rotated, the turntable level changes significantly (e.g. from 0.02 degrees to 0.15 degrees)
  • The flange was re-levelled between entry side and exit side measurements for the plumb bob and alignment jig measurements
  • With new nuclear ventilation filters, flow inside the hot cell perturbs the plumb bobs and prevents them from settling.
  • Nuclear ventilation had to be turned off momentarily for the plumb bob measurements
  • Nuclear ventilation is returned when working on the hot cell roof
  • Nuclear ventilation is controlled by turning the toggle on the electrical disconnect panel from 'hand' to 'off' ('auto' setting assumed not used)
  • Respirator and lab coat worn throughout plumb bob measurement job, air survey done by RPG after job (confirmed OK)
  • Area also 'taped off' during plumb bob measurements to prevent non-worker entry
• The coupler exchange resulted in around a 0.4mm shift in the target heights
• A shoulder screw and wood clamp is used to lock the plumb bob jig in place (old screw/nut missing, no other components in toolbox provides locating fit for pivot joint on jig)
• Assumed new plumb bob measurements more accurate due to better/more accurate 'levelling' equipment (digital level).