40m
QIL
Cryo_Lab
CTN
SUS_Lab
TCS_Lab
OMC_Lab
CRIME_Lab
FEA
ENG_Labs
OptContFac
Mariner
WBEEShop
|
40m Log |
Not logged in |
 |
|
Thu Apr 21 18:18:42 2022, yehonathan, Update, BHD, POX Alignment
|
Thu Apr 28 17:45:53 2022, Anchal, Update, BHD, POX Beam issues
|
Sat Apr 30 13:29:33 2022, Paco, Update, BHD, POX Beam issues --- fixed, ASL alignment on vertex chamber
|
Mon May 2 17:51:30 2022, Anchal, Update, BHD, POX Beam aligned on RFPD, YARM locked
|
|
Message ID: 16818
Entry time: Thu Apr 28 17:45:53 2022
In reply to: 16799
Reply to this: 16821
|
Author: |
Anchal |
Type: |
Update |
Category: |
BHD |
Subject: |
POX Beam issues |
|
|
[Anchal, Paco]
We investigated the low power issue with POX11 photodiode.
- We used a power meter to confirm that above 12 uW of power is reaching the ITMX oplev table.
- But the power reaching the photodiode was only 3 uW, because the 2 steering mirrors used were discarding half of the light. These mirrors were taken from former POP setup and are probably BS or meant for different incidence angle/polarization.
- We used flashlight to test that the photodiode gives a response, so it is not dead.
- We also put in a db15 breakout board in line to the PD and confirmed that power input is correct, temperature is nominal, enable is ON, and DC out is responsive to flashlight.
- So we decided to redo the path with Y1-45P 1inch mirrors. I found two such mirrors in the lab.
- When setting up the path again, I realized that the beam shape is not even. I took a photo of the beam on the card (see attachment 1) and indeed the POX beam that is coming to the table is half clipped.
- So tomorrow, we'll open the chamber and find out where this is happening. For now, I've setup a nominal path to the POX11 photodiode, but we'll tune it after we get a clear POX beam on the table.
|
|
|