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