Development of Cryogenic System for Soft X-ray Microscope

In order to reduce radiation damage in observing biological specimens, a cryogenic sample stage for soft X-ray microscope BL12 has started. The system was designed to image hydrated biological specimen at a temperature below glass transition temperature. The cryostat allowed the specimen to be treated both by cooled in nitrogen vapor and by cooled with heat conduction through liquid nitrogen. Using this system, the temperature of the sample stage was kept below 113 K for 50 min. Based on the cooling system, the cryogenic chamber was improved. This improved cryogenic chamber is compactly and high-performance device. Cooling power, stability, and cryogenic temperature range are sufficient for observing biological and polymer specimens. After performing at a test vacuum system, the chamber was installed in BL12. Under cooling condition with the cryogenic chamber, both upper stream and lower stream heads realized non-leak and the chamber vacuum was < 4×10-5 Pa