Chad and I did the helium spray leak check on TM2 GE and MSP water lines at SHC this morning. We confirmed the GE leak on water blocks. We can not found the MSP leak by using the helium spray since its leak rate in TCS is much smaller than GE leak.  The leak check process are as below:
Leak detector are calibrated before the check.
GE lines : Base leak rate 0.0 X E-9 atm.cc/sec, base pressure 0.0 XE-4 torr.
Chad sprayed 5 psi helium to GE lines soldering joints  for 5 second, no response on leak detector.
Chad sprayed 5 psi helium to GE lines water blocks( between blocks seal surface) for 5 seconds, Leak detector response to 8 XE-9 atm.cc/sec right away.
Chad sprayed  5 psi helium to GE lines soldering joints for 5 seconds again, No response on leak detector.
Chad sprayed 5 psi helium around the source tray and to vacuum duct for 5 seconds more, No response on leak detector.
MSP lines: Base leak rate 0.0X E-9 atm.cc/sec, base pressure 0.0 X E-4 torr.  Chad did same thing as he did on GE lines. no response on LD. Chad repeated the test and prolonged the spray time to 10 seconds, No response.
The conclusion: It is pretty clear we have a leak on GE line water blocks seal.  MSP lines leak could not be found by helium spray in SHC since it is a small leak.