Ushiba, Tanaka

Ushiba-san found that GR beams did not reach the input mirrors even though PR3(SR3) alignment was restored. According to each GR input monitor on POP/POS, GR beams seems to reach to POP/POS table. So I entered the mine and checked the GR laser shutters works or not.

At first, I checked the GRX laser shutter on the POP table. Since the display showed something, the driver itself seemed to be turn on. In this state, I tried to open and close the shutter by medm screen. However, the shutter did not work. Then, I tried to open and close the shutter manually by using the wheel on the driver. I confirmed that I could open and close the shutter manually. So the driver and shutter themselves seems to work. Again, I retried to open and close it by medm screen. Then, I could do so.

Similarly, the GRY shutter could be recovered by the same procedure.

We are not sure of the reason why. One of possibilities is that the current amount to work the shutter is not enough. We used Thorlabs SH1 as the GR shutter and  Thorlabs KSC101 as the GR shutter driver. However, KSC101 is designed for a half inch shutter but SH1 is a 1-inch shutter. So we used the driver to work the larger shutter than one that makers expect. Maybe while the driver keep working, we can move the shutter remotely. However, the driver is turned off once. we may need to move the shutter manually once in order to move it remotely .