camilla.compton@LIGO.ORG - posted 17:19, Wednesday 30 April 2025 - last comment - 14:38, Monday 02 June 2025(84193)
ISC Alignment Work, Day 1 in HAM1: Majority of REFL Path optics aligned.
Keita, Elenna, Oli, Rahul, Camilla
Summary: Majority of REFL path optics are aligned. Need to beam profile and finish LSC and ASC REFL diode placement on this path and place/check all beam dumps.
This morning, Keita opened the light pipe, locked the IMC but couldn't see the beam as nicely as he did on AS_AIR yesterday. Since that time he had restored PR2 and PR3 to a time we were last locked. He reverted those changes as we could see the beam back at AS_AIR. Checked again IM4 trans QPD was the same as yesterday.
- The beam coming out of the spectrum port was not centered on the REFL optics that had been placed as per D1000313-v19. We checked Corey's photos to compare REFL optics position relative to periscope and the D10002313 drawing and convince ourselves the beam in correct just the drawing of it is incorrect.
- Firstly checked the incoming beam was centered on M14 and the reflected beam off this was dumped on the HiPWR beam dump which was moved to it's final position.
- Beam centered on HW1
- Beam centered on M17 and the reflected beam off this was dumped on the HiPWR beam dump
- Beam centered on M1 and headed towards M2
- Beam centered on M7, following the correct beam path off the table and dumped but a temporary dump (before we put in BDV1)
- Beam centered on M2 and headed towards center of RM1.
- Transmitted M2 beam dumped by BD8
- Rahul got RM1 and RM2 damping loops working so they are now in DAMPED nominally (changed OPS whiteboard) Rahul set sliders to zero.
- Beam centered on RM1 and headed towards center of RM2 (we had to turn RM1 in YAW)
- BD16 placed behind RM1 but beam can't be seen to align to.
- Placed M5 in roughly correct place
- Beam centered on RM2 and headed towards center of M5 (we had to turn RM2 in YAW)
- Beam centered on M5 and headed towards the SLED
- There was a fair bit of iteration of M2 and M5 here to get the beam to be aligned and centered on all optics through the SLED, still needed to adjust SLED mirror to get it centered on the final mirror.
- Adjusted the SLED steering mirror (in the position +X -Y) on the SLED to center the beam on the ASC REFL B diode steering mirror.
- Adjusted ASC REFL B diode steering mirror so that picomotors had some range left.
- Beam centered on M6 and headed towards L1/M18
- Beam centered on L1
- Beam centered on M18 and headed towards LSC REFL A and LSC REFL B
- We stopped here before fully aligning these too diodes
- LSC REFL A is aligned by eye and 22cm from L1 (+222mm FL)
- LSC REFL B is 20cm from L1 and will be moved to match LSC REFL A tomorrow.
Additionally M16 was placed roughly in the correct position, all optics are now on HAM1 (apart from PM1) and the class-B pans are empty and packed up.
Left IMC locked.
Attaching a bunch of photos of the current alignment:
(I don't have the names of the optics on the SLED so I'm calling them by the order that the beam goes through them)
- Alignment from RM2 onto M5 (attachment1, attachment2)
- Coming from M5, through M6, and onto first lens on SLED (attachment3)
- Coming through first SLED lens onto second SLED lens (attachment4)
- Through SLED lenses and onto first steering mirror (attachment5, attachment6)
- Alignment onto SLED pico mirror (attachment7)
- Top view of pico showing that there is available range in both pitch and yaw (attachment8)
- Distance between L1 and front of LSC REFL A (L1 focal length is 222mm) (attachment9, attachment10)
- Distance from LSC REFL A to M18 (attachment11)
- Distance from LSC REFL B to M18 - needs to be moved closer (attachment12)
About REFL WFS sled:
Tagging for EPO