Sawada, Uchiyama, Kimura(remote), Yasui(remote)
We started warming up EX about 4 PM.
(1) We Connected 5 TMPs(#34, 35, 38, 36, 30).
(2) We stopped 3 Ion pumps(#35, 36, 30)
(2) Stop one cryocooler for the payload(P-54) and one cryocooler for teh radiation shield(P-55).
*We did not turned on 8K shield heater for EY because Kimura-sama found an issue for the medm screen for the heter control.
at 17:31 GVey was closed by the interlock system due to increase of the vacuum pressure. Finally the vacuum pressure reached the order of 10^-3Pa.
Once we opened GVey intensionally and observed the trend of vacuum pressure. The vacuum pressure continued to rise, so I decided to close it again and watch it like this overnight.
Yamaguchi, Uchiyama
Since the vacuum pressure level in EY reached 6.5E-6Pa, we opened GVey at 9:17 AM.
Nakagaki, Yasui
We stopped the other cryocooler for radiation shield(P-53) at 10:46.
The compressor operating time was 17970.9h.
Nakagaki, Yasui
We stopped two duct shield cryocoolers.
10:55 Yea (The compressor operating time was 12438.6h)
10:56 Yer (The compressor operating time was 20314.0h)
GVetmy was closed by the interlock at 5:59 on December 27, 2025, because the vacuum pressure at Y_30 reached 1E-3 Pa.
After closing GVetmy, the vacuum pressure in EYC is decreasing.
Since the temperature of the BRT side of the duct shield is still under 150K, increase of the vacuum pressure in EYC due to water evaporation may happen later again.
We turned on the heater on the arm side of duct shield of EYC at 8:15, because the temperature of this duct shield was enough higher than 150K.
The heater power is about 8W.
Note that we did not turned on the BRT side at this time.
Since I failed upload the screenshot of the heater control panel for the Arm side of the duct shield yesterday, I upload it here.
We turned on the heater on the BRT side of duct shield of EYC at 19:40, because the temperature of this duct shield was enough higher than 150K.
The heater power is about 8W.
Now, both side of EYC duct shields are heating up.
Since the temperatures at the cold heads of the cryocoolers for the duct shields of EYC reached the room temperature, we turned off both sides of the duct shield heaters at 9:45 a.m. on January 5th, 2026.