chad fisher wrote:

The heat shield circuit was pressurized with air (15-20 psi) and snoop applied to the water block joint and brazes. Bubbles formed at the joint between the two water blocks indicating that the leak is a c seal problem. Pictures attached but also on docushare Collection-11285.

 Last night prior to this leak check the Heat Shield was pumped on and helium sprayed on the circuit. The pressure was 0.0 x 10^-4 Torr. The leak was traced to water block. response time was 2 seconds and went from 5.5 x 10^-8 to 1.6 x 10^-6 atm*cc/sec. There was also a response without spraying helium (drift from the nozzle). The results of this testing prompted the testing completed in Chads elog.