I did a helium pressure test on heat shield circuit. The leak detector is concected to the TM4 primary vacuum system.The IG1 is 1.1xe-6 torr,PNG4 is 1.5 x E-6torr,and IG4 is 2.1 XE-6torr.leak detector base leak rate:0.0xE-9 atm.cc/sec, base pressure is 0.0x E-4 torr.Applied 80psi helium to heat shield circuit for 4 mins .There is no any response on leak detector during 4mins time. There is no pressure change during the test time. The heat shield circuit is leak tight.