It took a long time(more than 1 hour)   to pump down the TM4 window  cooling line during leak check time. The base leak rate could only be pumped to 5.8xE-9 atm.cc/sec.Base pressure is 0.0xE-4 torr which is bottom reading. Chad and i did the leak check at this base leak rate .No leak had been found. The window cooling line is leak tight at this stage. A pressure helium test will be fulfilled in conditioning station on this cooling line later.