I turned off ETMY IM heater.

I applied current of 0.074 A to ETMY IM heater (fig1).

ETMY IM temp kept increasing, in contrast with  ITMX IM temp as Fig.1. It is strange.

Fig.2 shows the volatile cooling performance of the cryocooler for REF4 for ETMY as you know. So it is better to stop this cryocooler ore try stop and restart.

I reduced the heater power as shown in fig1.

EX Im temp is decreasing with fluctuation again. EY IM temp is also decreasing slowly (Fig.1).

Fig.2 seems to show the decrease in the heat reduction rate of EX_4K_REF2/4_4K_Head when the heater was on. while no relation was found btw EY IM temp and EY_4K_REF2/4_4K_Head.

Fig.3 shows the close-up of the recent 1-day data. In EX, the IM temp and REF2/4 4K head temps have a clear correlation. While, in EY, no correlation between the IM temp and REF4 4K head temp. Very strange?

The temps' changes of EXY IMs seem to become smaller.

I increased the heater power as shown in fig1.

EXY Im temps. EX Im temp is increasing. EY Im temp is near constant.

The current was increased by changing the voltage to 8.900V.

The current was increased by changing the voltage to 9.197V.

The current was decreased by changing the voltage to 9.500V.

I reduced the heater power.

I reduced the voltage from 4 to 3 to accelerate the IM temp reduction.

I reduced the voltage from 2.5 to 1.0 to accelerate the IM temp reduction.

I reduced the voltage from 1.0 to zero to accelerate the IM temp reduction. However, no remarkable temp reduction happened during my recent actions. It is strange. My setting is right?

I increased the current for IM heater on ETMY to warm up ETMY.

I increased the current for ETMY IM heater.

I increased the current for ETMY IM heater.

I reduced the current for ETMY IM heater because ETMY temp is now more than 100K.

I increased ETMY IM heater for further warming up (fig1).

The temperature of IM of EY reached the critical temperature! It is much faster than we expected (Fig.1). Fig.2 shows the temperatures in the EY cryostat. Other temperature seemed to be lower than the critical temperature. Rather, the temperature of 40K heads of all cryocoolers started to reduce after the heater current increased.

However no change in the Qmass data at present. Of course, the temperature of the test mass should be cooler than IM's at present. According th the past experiences in the radiation duct shield, slight enhancement of water started from around 145K~150K. The outgas from IM was just being absorbed on other cooled area in the ceyostat and did not reach the Qmas? 

3 days have passed after the warming up. Both EX/Y IMs temperatures were over the critical temperature. However, it seemes to be difficult or to take long time to reach 180K or more without more current for the IM heaters.

I turned off IM heater for cooling ETMY again.

IM Temperatures are still decreasing. However, IY and EX temps decreased rapidly. So it is better to set some amount of current for IY/EX heater within one or two days.