To RHESSI collaborators:
RHESSI has been successfully operating in space for over 16 years now, and we will be rejuvenating the detectors once again through an "anneal" procedure. RHESSI’s germanium detectors degrade steadily over time due to radiation damage from charged particles, and heating up the germanium restores lost sensitivity and resolution. The detectors will be heated up from their operating temperature of ~155 K to ~85 deg C (~358 K), held at that temperature for two weeks, and then cooled back down. These detectors have been previously annealed five times, most recently in 2016.
We plan to start the anneal today, and the entire procedure is estimated to take about two months. During this time period, RHESSI will be unable to make X-ray or gamma-ray observations. If you have any questions about this anneal, please feel free to contact me.
Albert Shih RHESSI Deputy Mission Scientist
————— Albert Y. Shih Solar Physics Laboratory, Code 671 NASA Goddard Space Flight Center Greenbelt, MD 20771 Office: 301-286-1843