Output Mode-cleaner

Meetings

Installation work

2018/10-11

Reports

Requirement

Shot noise increase due to the signal reduction by the OMC and residual spatial higher order modes after the OMC should be less than 5%.

Optical Design (updated 19/8/11)

item	RoC	Beam Raidus	Misc
OMMT1	13.16m	4.46mm	Dia: 99.95mm, thick: 55.58(largest), wedge: 2.45deg (measured by Hirose-san 2018)
OMMT2	44.39m	2.68mm	Dia: 99.97mm, thick: 55.08(largest), wedge: 3.3deg (measured by Hirose-san 2018)
OSTM	flat	TBA
OMC1	flat	444um
OMC2	flat	444um(X)/447um(Y)
OMC3	1.80m	604um
OMC4	1.80m	604um
DCPD	--	592um

Space	Distance	AOI
SRM-OMMT1	5.63m	3.07deg
OMMT1-OMMT2	2.60m	3.07deg
OMMT2-OSTM	2.97m	90deg
OSTM-OBS1	0.30m	90deg
OBS1-OMC1	0.03m	0.078deg
OMC1-OMC2	0.357m	3.00deg
OMC2-OMC3	0.359m	3.00deg
OMC3-OMC4	0.357m	3.00deg
OMC4-OMC1	0.359m	3.00deg

Suspension Design

Total mass to be suspended	13kg
Number of suspensions	3
Blade spring size	220mm x 53mm
Radius of curvature	190mm
Distance from a blade end to a suspension wire	203.5mm
Blade material	MAS-1
Blade mass	4.3kg

JGW-G1707050-v1

Control Scheme

LSC
Dither frequency	1kHz (tentative)
Dither optics	OMC3 or OMC4
Signal extraction port	OMC trans DCPDs
ASC
Dither frequency	not yet decided
Dither optics	OSTM (tentative)
Signal extraction port	OMC trans DCPDs; on-board QPDs are used for the course alignment

OMC Venting and Repumping Procedure with HPL preparation with PLL (2023/Jan/30~Feb/3)

(Jan 30, Mon)
- Before 9:00: FPMI realignment (Yokozawa-kun), Preparation for venting (Kimura-san, M.Takahashi-san), Turning on all FFUs in the OMC area.
- Keep IMC lock using the present fiber laser. Stanby of R.Takahashi-san and Aso-kun for monitoring.
- After informing the start of venting from Kimura-san to R. Takahashi-san, Kimura-san starts venting.
  - If OMMTs realignment with pico is necessary, It will be done.
- After finishing venting, Kimura-san informs to R.Takahashi-san, Aso-kun, Miyakawa-kun and Miyoki.
- Miyoki changes the PSL from OBS to Work mode at this time with IMC ASC? or around after all works are done on Jan 30?
  - IP2? HV drift monitoring.
  - Offload of IMC suspensions and IP1/2?
- (Para)Just after the PSL mode change, Miyakawa-kun starts FB -> HPL changing and IMC control with HPL.
- (Para)After closing the GV between SRM/SR2, Kimura-san starts opening the bellows at GV. So no laser to OMC area. Kimura-san starts the repair work. We would like to avoid removing the all bellows duct to reduce the risk to produce another leak on the healthy opposite side.
(Jan 31, Tue)
- Kimura-san dose repair work and closes again. Also, after checking no problem happens in the vacuum level in SRM, the GV between SRM/SR2 is opened. Check the IR beam to and from OMC by ??.
- Recover the operated FFU number in OMC as before this wrok.
- After this work, R.Takahashi-san dose health check for OMC suspensions in this day or tomorrow morning
- Miyakawa-kun PLL control adjustment with Izumi-kun. Sometimes, IMC unlock is expected?
  - The GR frequency will be kept, while the HPL IR frequency will be adjusted by changing the crystal temp.
(Feb 1, Wed)
- Morning
  - Miyakawa-kun's HPL works.
- Noontime
  - From 13:00?, Kimura-san informs R. Takahashi-san and Aso-kun about the start of pumping. The Kimura-san starts pumping gradually.
    - If OMMTs realignment with pico is necessary, It will be done.
(Feb 2, Thu)
- Miyakawa-kun change the HPL to FB again? After this or earlier timing, the PSL room should be set to OBS mode again.(Or should we do in the week end holidays?)
- Kimura-san/Yasui-san start the vacuum leak check. If no leak is verified, we will decide when we can open the GV, judging from the vacuum level reduction speed.
  - Opening GV might result in the realignment of the IF beam to OMC.
(Feb 3, Fri)
- DGS maintenance day.

OMC Blade Damping (2023/June/22)

Somiya-kun's Presentation