KAGRA Logbook

IOO (IMC)

keiko.kokeyama - 13:50 Friday 28 July 2017 (3175)

MC Oplev Calibration

We re-calibrated MC oplevs again.

Since mirror angle d_theta is:
Regular configuration d_theta = dx / (2*lever arm length)
Folded configuration d_theta = dx / (8*lever arm length),
calibration factor [urad/cts] = slope [mm/cts] / (2*lever arm length [m]) * 1000

MCE - lever arm length 0.95m
PIT 145 [urad/cts]
(slope 0.28 [mm/cts], linear range ~ 0.4 mm)

YAW 145 [urad/cts]
(slope 0.28 [mm/cts], linear range ~ 0.5 mm )

MCI - lever arm 0.86m
PIT 312 [urad/cts]
(slope 0.54 [mm/cts], linear range ~ 0.85 mm )

YAW 286 [urad/cts]
(slope 0.49 [mm/cts], linear range ~ ? micrometer range out)

MCO (folded) - lever arm 0.85 m
PIT 102 [urad/cts]
(slope 0.69 [mm/cts], linear range ~ 1 mm )

YAW 97 [urad/cts]
(slope 0.66 [mm/cts], linear range ~ 0.75 mm)

Lever arm lengths were taken from klog #570.
I also upload calibrated spectra (it was taken at a noisy work timing, with people walking around MCF).

>> oplev_calibration

calEP =

145.4689

calEY =

-145.3631

calIP =

311.5953

calIY =

-285.8698

calOP =

102.2749

calOY =

-96.8982

ans =

297.0409

ans =

256.4694

ans =

579.8634

ans =

561.8483

ans =

163.6023

ans =

152.1214

>> close all

Images attached to this report

Non-image files attached to this report

oplevcal.pdf

Comments to this report:

yuta.michimura - 20:30 Tuesday 28 November 2017 (3721)

[Koji Nagano, Akutsu, Michimura]

We have updated the oplev calibration factor for IMC mirrors to take the incident angle into account (see klog #3536).

MCe PIT 145 [urad/cts] -> 180 [urad/cts] (incident angle 36.5 deg) MCi PIT 312 [urad/cts] -> 312 [urad/cts] (incident angle 0.23 deg) MCo PIT 102 [urad/cts] -> 107 [urad/cts] (incident angle 17.8 deg)

yuta.michimura - 10:02 Wednesday 29 November 2017 (3727)

I learned from Keiko that MCe oplev was actually calibrated using a tilt sensor. I revereted the calibration factor.

MCe PIT 180 [urad/cts] -> 145 [urad/cts]

keiko.kokeyama - 19:47 Wednesday 29 November 2017 (3732)

Sorry the correct factor is indeed 180 and it was put back!

The used old numbers 145 from this klog was after tilt sensor (which gave the right number including the PIT cos factor) was not include the PIT cos factor. I completely forgot about this and gave the wrong info to yuta. My apologies!

kouseki.miyo - 9:16 Wednesday 24 March 2021 (16314)

Today (2021/03/23), I calibrated MCo oplev to test my script in here.

Although I moved QPD stage by micrometer in both horizontal and vertical direction, the vertical direction was out of range of the micrometer when the beam was in center of QPD. We should adjust the position of the QPD in vertical direction.
Anyway, I could calibrate only yaw corresponding to horizontal direction as shown in attached figure. The figure shows values of all Oplev dofs (PIT, YAW, SUM, CRS) which are signal after the sensing matrices named OPLEV2EUL and SENSALIGN. Horizontal axis is the position of the micrometer in horizontal direction. As you can see, I could get the slope value of 1/-1.52=-0.657 [mm/count] for yaw direction, which is consistent with klog#3175 but sign is fliped.

Next, I will adjust the QPD in vertical direction of MCo oplev, after that, I will continue the calibration work for other IMC suspensions.

Images attached to this comment

kouseki.miyo - 18:13 Monday 12 April 2021 (16450)

Yokozawa, Miyo

We calibrate MCI oplev by using the semi-auto tool in the {vis}/common/script/autocommissioning/oplev. commit is here.
We got the slope value [mm/count] as bellow;

MCI_PIT : 1/2.31 = +0.43 [mm/count]
MCI_YAW : 1/-2.10 = -0.48 [mm/count]

Today, we could not measure other profiles: beam power, beam profile and wavelength of the light source because of lacking some tools.
Tomorrow we will continue the several measurements for all IMC suspensions after we found the tools.

Images attached to this comment

takaaki.yokozawa - 8:51 Wednesday 14 April 2021 (16462)

[MiYokozawa]
We calibrated the MCe optical lever.
The result will appear soon