[Takahashi, Ikeda]

We tested the ribbon heaters in the top chamber.

1. Winded two ribbon heaters at the top chamber.
2. Covered the heaters with Al foil.
3. Put the temperature controller on the top chamber.
4. Heated up the top chamber upon  63 deg. The temperature in the BF was not changed. LVDT in the F0 showed small drift of 20um (plot).