Institut de recherche sur les lois fondamentales de l'Univers

KAGRA is the cryogenic interferometric gravitational wave telescope designed for the direct detection of the gravitational waves from the astronomical sources.

To achieve the best sensitivity, one of the most outstanding challenges is to cool and keep the mirrors at 20K to reduce the thermal noise.

We developed four cryostats and sixteen very-low-vibration cryocooler units to accomplish our purpose. The outline of the cryogenic design, fabrication, and the results of the cryogenic performance test of the cryostats and cryocooler units are presented in this seminar.