[Lucia, Koki]

Troubleshooting - F0 GAS actuator doesn't work

• We investigated whether the actuator of the F0 GAS can displace the keystone.
• A DC voltage was applied to the actuator coil by using a stabilized DC power supply TEXIO PW18-3AD.
  • The DC power supply was connected directly to the cable that goes to the feedthrough flange, without using the coil driver.
• In any trials, the F0 GAS actuator cannot make an offset in the height of the keystone.
  • No variance could not be observed in the signals of either F0 GAS LVDT or BF damper vertical.
  • When we output the DC voltage, the DC power supply was in voltage-limited mode
  • When we set the voltage output as 7 V, the output current was ~ 0.33 mA
    • This result is consistent with the measurement of the resistanse of the actuator coil that was ~ 213 Ohm.
    • We checked the resistance of the coil with a handy digital multimeter, but didn't measure its inductance.
• Therefore, we concluded that some causes of malfunction could be inside the vacuum chamber.

Next step

• Investigation of the F0 GAS actuator coil
  • MiraPro colleagues will kindly open the EYV chamber in tomorrow's morning
  • Checking the inductance of the coil
    • I borrowed another digital multimeter from the AEL tools in which inductance measurement is available.
  • If a fatal bug was found, we will use the BF damper vertical actuators as an equivalent actuator to the F0 GAS's one because the F1, F2, and F3 GAS are stuck now.
  • This debugging will be finalized at latest by tomorrow.