Transmission Monitor Telescopes (TMS)
Related subgroups: IOO, MIF, VAC, CRY, VIS...
Also called "beam reducing telescope (BRT)" in LCGT.
Contents
Scope
- Transmission monitors for IR/Green beams.
General Description
Applicable Documents
Functions
- Collect 1064nm and 532nm light transmitting ETMs.
- Monitor the off-centering and pitch/yaw fluctuations of the ITMs/ETMs relative to the preselected optical path.
- Monitor the shape of the beam modes that transmit the arm cavity.
Requirements
- For each TMS,
- 2QPDs for 1064nm are required to monitor off-centering of the beam; one is for high gain, the other is for low gain.
- 2QPDs for 1064nm are required to monitor pitch/yaw misalignments of the beam; one is for high gain, the other is for low gain.
- 2QPDs for 532nm are required.
- Remote stirring mirrors for QPDs are required at least in the initial commissioning phase.
- Remote actuators for TMS chassis would be required.
- CCD monitors for monitoring the beam mode transmitting the ETM are required.
- Optical levers (or equivalent local monitors) are required.
- Suspension system will require more signal channels?
- Shutters for high gain QPDs are required.
List of Channels
- For each TMS,
Name
Type
Input ch#
Output ch#
Purpose
Used By
QPD1H
1064nm QPD
0
4
Mon. off-centering, high gain
MIF
QPD1L
1064nm QPD
0
4
Mon. off-centering, low gain
MIF
QPD2H
1064nm QPD
0
4
Mon. misalignment, high gain
MIF
QPD2L
1064nm QPD
0
4
Mon. misalignment, low gain
MIF
QPD1G
532nm QPD
0
4
Mon. off-centering, low gain
MIF
QPD2G
532nm QPD
0
4
Mon. misalignment, low gain
MIF
Stirring mirrors for QPDs
TBD
24
0
Remote stirring mirrors for QPDs; 6x2x2ch
MIF
CCD monitor1
TBD, for 1064nm
On/Off?
VIDEO signal?
CCD monitor
---
CCD monitor2
TBD, for 532nm
On/Off?
VIDEO signal?
CCD monitor
---
Shutters
TBD
2
0
On/Off of shutters for high-gain QPDs
MIF
- For each TMS suspension and local sensors,
Name
Type
Input ch#
Output ch#
Purpose
Used By
Actuators for TMS
TBD
12?
0
Remote actuation for TMS
---
Optical levers for TMS
TBD
0
8
OpLev QPDx2?
---
Other, related to the suspension itself
TBD
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Naming Conventions
- TBD
Locations
- At the dedicated chambers in back of ETM chambers