KAGRA Logbook

VIS (BS)

fabian.arellano - 11:10 Monday 15 April 2019 (8645)

Alignment recovery after pump down.

This morning I recovered the alignment of the beam splitter prior trabsfer function measurements. Highlights are the following:

The BF was successfully set to its nominal position, which is zero, using the fishing rod only.
The SF F1 was set to 488 µm. The fishing rod does not allow us to set it to zero. We can try to set it to zero using the coil-magnet actuator but we might not need doing it.
It was not possible to set the the top filter F0 to zero with the fishing rod only. I had to use the coil-magnet actuator with 9,800 counts per the DC control system.
The coil-magnet actuation needed to set the IP in a good position is relatively low:
- H1: -51 cnt.
- H2: 825 cnt.
- H3: -550 cnt.
I recovered the optic alignment using the IM picomotors. The largest OSEM output of all was H2 with 9006 counts and 111 µm.
The following step is to measure transfer functions.

Comments to this report:

fabian.arellano - 11:21 Monday 15 April 2019 (8647)

The current procedure to set the system ready to measure transfer functions is

From a state in which the DC control system is on, the HOLD OUTPUT feature must be activated in each of the DCCTRL windows for the three GAS filter actuators and the three IP actuators.
Using Guardian the suspension is to be set in NEUTRAL mode. This leaves the master switch on.
The test channels are to be turned on manually for each degree of freedom.
The syem is ready for transfer function measurement.

This procedure will likely be simplified in the future with Guardian.

fabian.arellano - 19:19 Monday 11 November 2019 (11465)

In case you don't see the plot attached please click here.

The temperature on the 15th of April 2019 in the BS clean booth was 24.5 °C.

Images attached to this comment

shinji.miyoki - 19:58 Monday 11 November 2019 (11466)

24.5C is the target temp ?? If so, let's turn off BS-C cooler.