This is a continuation of work detailed in E-Log #129 and #140.

- Static water test performed on the target cooling lines:
     - Test setup assembled and leak checked by pressurising with house air, submerging in water and checking for bubbles (see photos)
     - System filled, pressurized, and valved off on Friday Feb 13 at 5:30pm,  Gauge read 60psi
     - Checked Monday Feb 16 @ 9:00am.  Gauge read 56psi
     - Checked Monday Feb 16 @ 5:00pm.  Gauge read 56psi
     - Checked Tuesday Feb 17 @ 9:30am.  Gauge read 55.5psi  (0.5psi / 24hrs rate)

- Checked results with Dimo and he requested a helium leak check be performed with a newer model leak detector to quantify leak rate:
     - Using Varian 979 leak detector, pumped ~1.5hrs w/ cold trap to remove water
     - TP press: 0.0*10^-4 torr,  Base leak rate ~7.0*10^-9 atm cc / sec
     - Tested all normal leak check locations and did general helium flood with no response at all  (1.5psi helium pressure)
     - Over ~ 20 minute period the base leak rate gradually rose to 8.8*10^-9 atm cc / sec, at one point spiked to high 10^-9 level, then returned to base line
     - Reviewed results with Dimo, he requested test be repeated after the target sits vented overnight

- Target vented and left overnight, leak check repeated Feb 18 starting 9am:
     - 0.0*10^-4 torr TP pressure after ~5 mins
     - 10^-9 atm cc / sec leak rate level after ~20 mins
     - All locations sprayed with 1.5psi helium, general flood in ladder area --> no response (Dimo and Edi present)
     - Target deemed OK for use in beam line by Dimo, he requested the cooling lines be filled with helium after installation in b/l while leak checking T1 volume

- Target will be transported to the storage pit tomorrow (Feb 19) and is ready for use as the spare T1 target

The target had an obvious helium leak when first tested (E-Log #129 and #140), which could not be found when helium leak checking again after the static water test.  Some possible explanations are:  water remaining in the lines blocked the leak path,  water remaining in the lines froze when vacuum was pulled blocking the leak path, having water in the lines caused some corrosion or other deposit which plugged the leak.

The helium leak at plugged position 1 right side measured before the static water test is the same, or slightly less than the leak rate when the target was first removed from the beam line.  There were no T1 vacuum issues during the running period, therefore no issues are expected when this target is put in service again.