Helium loss of XRS

Helium, the cryogen of XRS, was totally lost away and XRS is not operational any more. It happened in the morning of August 8 (11:25 JST). XRS team found the He tank temperature was about 6-8 K, which should be 1.3 K. It means the tank is empty and warmed up to this temperature. There are many other data to suggest this incidence. The situation and reasons of this incidence is being investigated.

XRS detector system has been working properly at least first 19 days with energy resolution of 7 eV at the temperature of 60 mK. Therefore its technology is almost proven, but we can not get astrophysical data any more with XRS.

Though one of the main instruments is lost, we still have X-ray CCD camera (XIS) and hard X-ray detector system (HXD). We will continue initialization process of XIS and HXD and try to get best science with these instruments.

ISAS/JAXA Department of High Energy Astrophysics
Last Modified: Monday, 22-Aug-2005 15:43:21 JST