Summary of ETMX suspension cooling issues
(I’m sorry that I didn’t upload these information.)
- 29th June : We started cooling down. Then we found the a little bit strange behavior. (5424)
- 2nd July : We found the strange behavior of ETMX suspension. (5447)
- 3rd July : We tried to restore the suspension. For example, we tried to adjust the Mirror yaw angle using picomotor of the BF and TM-oplev signal. However we was not able to restore…
- 4th July : We decided that the payload was attached to somewhere. (5463)
- 5th, 6th July : ETMX suspension warm up (5470, 5476, 5477)
- 9th July : We opened flanges( ø800mm machine room side of the cryostat, both flanges of the BF part, and Top of EXV chamber). Then we checked the payload condition. We found the attaching part between payload IM Recoil mass stage and earthquake stop(frame) bolt. And VIS parts work is here ->(5486).
- 10th July : we checked and fixed attaching issue. And we started to pumping down. (5491)
- 11th July : F2 Filter check (5504).
- 13th July : We started cooling down. (5527)
- 17th July : GAS filter transfer function measurement, and Okutomi-san’s comment (5537, 5539)
- 20th July : We found the cooling down trouble. 50K_cryocooler(b) and 4K_cryocooler(d) performance was not good. At first we thought that the cryocon (temperature monitor) trouble. So, we checked the current source of the cryocon and grand condition, but we didn’t find any issue. Therefore we thought the cryocooler trouble.
- 23th, 24th July : we changed the valve unit of the 50K cryocooler(Fig.1), since Kimora-san said that we should change it. And we stoped the 4K cryocooler No.4 for restart it.
- 25th July : we started the 4K cryocooler No.4.