40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
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ID Date Author Type Categorydown Subject
  12054   Wed Mar 30 11:35:24 2016 steveUpdatesafetyBS visitor's viewport is protected with lexan

Quote:
The four horizontal viewports of arms are protected
by 3/8" thick, 8.5" OD Lexan disk of MR10 Polycarbonate.

ITMX, ETMX, ITMY and ETMY ccd cameras are not focused now.


BS visitor's viewport glass is now covered with Lexan MR10

Note:
this Lexan cover is in vertical orientation so becomes lose when the black anodized cover is removed.
It needs to be held in place

while it's housing is taken off.
  12082   Tue Apr 19 10:58:53 2016 SteveUpdatesafetysafety scans at PSL & tables

The PSL had one 1064 nm beam to be blocked around the north east side. The end enclosures are fine.

 

 

  12134   Wed May 25 11:51:40 2016 SteveUpdatesafetySURF 2016 safety
Quote:

Hello, I am Varun Kelkar. I will be working at the 40m lab as a SURF student this summer with Eric Quintero on Audio processing for real time control system signals. This week I will mostly be working on implementing basic DSP C-code offline. Currently I am trying to write a code for noise whitening.

-Varun

Varun has received 40m specific basic safety training today.

  12141   Tue May 31 16:52:58 2016 SteveUpdatesafetyNONO

Please do not place anything on the top of the cabinets that is not tied down. It will end up on our head in an earth quake.

 

Attachment 1: nono.jpg
nono.jpg
  12157   Wed Jun 8 10:20:14 2016 SteveUpdatesafetySURF 2016 safety

Aakash Patil received 40m specific basic safety training.

Quote:
Quote:

Hello, I am Varun Kelkar. I will be working at the 40m lab as a SURF student this summer with Eric Quintero on Audio processing for real time control system signals. This week I will mostly be working on implementing basic DSP C-code offline. Currently I am trying to write a code for noise whitening.

-Varun

Varun has received 40m specific basic safety training today.

 

  12228   Wed Jun 29 15:34:00 2016 SteveUpdatesafetySURF 2016 safety

Praful Vasiceddy received 40m specific basic safety training.

Quote:

Aakash Patil received 40m specific basic safety training.

Quote:
Quote:

Hello, I am Varun Kelkar. I will be working at the 40m lab as a SURF student this summer with Eric Quintero on Audio processing for real time control system signals. This week I will mostly be working on implementing basic DSP C-code offline. Currently I am trying to write a code for noise whitening.

-Varun

Varun has received 40m specific basic safety training today.

 

 

  12311   Tue Jul 19 15:16:43 2016 SteveUpdatesafetysafety training

Our new graduate student Lydia received 40m specific safety training.

  12479   Fri Sep 9 11:24:15 2016 SteveUpdatesafetysafety training

Visiting graduate student Teng Zhang from Glasglow received 40m specific safety training yesterday.

  12565   Mon Oct 17 14:48:12 2016 SteveUpdatesafetysafety training

Ashley Fowler  "high shool" student received basic 40m safety training and Lydia is her guarding angle.

 

  12705   Thu Jan 12 10:14:49 2017 SteveHowTosafetyclosing a door

The door was not locked this morning.

Please do not use this door if you can not close it!

Last person leaving the lab should check that the latch is cut by the strike plate.

Attachment 1: odc.jpg
odc.jpg
Attachment 2: howtocloseadoor.jpg
howtocloseadoor.jpg
  12706   Thu Jan 12 13:43:02 2017 ranaHowTosafetyclosing a door

This is one of those unsolved door lock acquisition problems. Its been happening for years.

Please ask facilities to increase the strength of the door tensioner so that it closes with more force.

  12707   Thu Jan 12 13:45:58 2017 SteveHowTosafetyclosing a door

It was requested this morning.

Quote:

This is one of those unsolved door lock acquisition problems. Its been happening for years.

Please ask facilities to increase the strength of the door tensioner so that it closes with more force.

 

  12868   Mon Mar 6 09:12:59 2017 SteveUpdatesafety crane inspection 2017

All 3 cranes inspected by professional Fred Goodbar of Konecranes and load tested with 450 lbs at max reach on Friday, March 3, 2017

 

 

Attachment 1: inspection_2017.jpg
inspection_2017.jpg
  12913   Tue Mar 28 16:47:40 2017 SteveUpdatesafetyProjector bulb is out again

Three replacement bulbs ordered

Rana can discribe how it happened.

IF A LAMP EXPLODES

If a lamp explodes, the gas and broken shards may scatter inside the projector and they may comeout of the exhaust vent.
The gas contains toxic mercury.
Open windows and doors for ventilation.
If you inhale the gas or the shardsof the broken lamp enter your eyes or mouth, consult the doctorimmediately.
Quote:

This bulb was blown out on Feb 4, 2017 after 2 months of operation.

 

 

  12921   Fri Mar 31 10:16:07 2017 SteveUpdatesafetylaser safety glasses annual inspection

Laser safety glasses cleaned in " Dawn Ultra " mild soap - water solution and measured for 1064 nm transmission at 150 mW
 

Attachment 1: march2017.jpg
march2017.jpg
Attachment 2: 2017march.jpg
2017march.jpg
  12927   Tue Apr 4 11:24:21 2017 SteveUpdatesafetyProjector bulb is out again

Shipped out for repair.

Quote:

Three replacement bulbs ordered

Rana can discribe how it happened.

IF A LAMP EXPLODES

If a lamp explodes, the gas and broken shards may scatter inside the projector and they may comeout of the exhaust vent.
The gas contains toxic mercury.
Open windows and doors for ventilation.
If you inhale the gas or the shardsof the broken lamp enter your eyes or mouth, consult the doctorimmediately.
Quote:

This bulb was blown out on Feb 4, 2017 after 2 months of operation.

 

 

It is back and running fine witth bulb  4-13-2017

  12970   Thu May 4 08:00:54 2017 SteveUpdatesafetysafety training

Freshmen Rebecca Zhang as " work study undergrad "  received 40m specific basic safety training yesterday.

  12994   Tue May 16 16:16:16 2017 SteveUpdatesafetysafety training

 Early surfs of India Jigyasa and Kaustubh received basic 40m specific safety traning.

Attachment 1: surfs2017.jpg
surfs2017.jpg
  13095   Wed Jul 5 10:23:18 2017 SteveUpdatesafetyliquid nitrogen boil off

The liquid nitrogen container has a pressure releif valve set to 35 PSI  This valve will open periodically when contains LN2

The exiting  very cold gas can cause burning so it should not hit directly your eyes or skin.  Set the pointing of this valve into the corner.

Leave entry door open so nitrogen concentration can not build up.

Oxygen deficiency
Nitrogen can displace oxygen in the air, reducing the
percentage of oxygen to below safe levels. Because the brain
needs a continuous supply of oxygen to remain active, lack
of oxygen prevents the brain from functioning properly, and
it shuts down.
Being odorless, colorless, tasteless, and nonirritating,
nitrogen has no properties that can warn people of its pres-
ence. Inhalation of excessive amounts of nitrogen can cause
dizziness, nausea, vomiting, loss of consciousness, and death
Attachment 1: liqued_nitrogen_boil_off.jpg
liqued_nitrogen_boil_off.jpg
  13144   Tue Jul 25 14:27:19 2017 SteveUpdatesafetysafety training

Kira Dubrovina and Naomi Wharton received 40m specific basic safety training.

Attachment 1: safety.jpg
safety.jpg
  13406   Mon Oct 30 08:08:06 2017 SteveUpdatesafetysafety training

Udit Kahndelwal received 40m specific basic safety traning on Friday, Oct. 27

  13496   Tue Jan 2 16:24:29 2018 gautamUpdatesafetyProjector periodically shuts itself off

I noticed this behaviour since ~Dec 20th, before the power failure. The bulb itself seems to work fine, but the projector turns itself off after <1 minute after being manually turned on by the power button. AFAIK, there was no changes made to the projector/Zita. Perhaps this is some kind of in-built mechanism that is signalling that the bulb is at the end of its lifetime? It has been ~4.5 months (3240 hours) since the last bulb replacement (according to the little sticker on the back which says the last bulb replacement was on 15 Aug 2017

  13592   Wed Jan 31 15:46:05 2018 SteveUpdatesafetycrane inspection

Annual crane inspection with load tests is scheduled for Monday, Feb 5, 2018 from 8 to 11:30am

Konecranes rescheduled this appointment to: Monday, Feb 12, 2018

  13630   Mon Feb 12 14:56:00 2018 SteveUpdatesafety crane inspection 2018

Our 3 cranes passed  professional  inspection. Fred Goodbar of Konacrane with 450 lbs load at full extension.

Certificates will be posted in 40m wiki as they arrive.

 

Attachment 1: ETMY.jpg
ETMY.jpg
Attachment 2: Vetex.jpg
Vetex.jpg
Attachment 3: ETMX.jpg
ETMX.jpg
  13843   Tue May 15 13:34:30 2018 SteveUpdatesafetysurf safety training

Pooja and Keirthana received 40m specific basic safety training.

  14031   Thu Jun 28 13:12:20 2018 SteveUpdatesafetysurf safety training

Shruti and Sandrine received 40m specific basic safety training this morning.

Quote:

Pooja and Keirthana received 40m specific basic safety training.

 

  14199   Tue Sep 18 14:02:37 2018 SteveUpdatesafety safety training

Yuki Miyazaki received 40m specific basic safety training.

 

  14263   Thu Oct 25 16:17:14 2018 SteveUpdatesafetysafety training

Chub Osthelder received 40m specific basic safety traning today.

  14978   Fri Oct 18 18:13:55 2019 KojiUpdatesafetyLaser interlock looks OK

I've checked the state of the laser interlock switch and everything looked normal.

  14980   Mon Oct 21 11:44:19 2019 gautamUpdatesafetyInterlock reconnected to Innolight controller

We also took this opportunity to re-connect the interlock to the Innolight controller (after it was disconnected for diagnosing the mysterious NPRO self-shutdowns). The diode pump current was dialled down to 0, the interlock wires reconnected, and then the diode current was ramped back up to the nominal 2.1 A. The fan to cool the unit remains mounted in a flaky way as we couldn't locate the frame Chub had made for a more secure mounting solution. 

It seems like the pointing of the beam out of the laser head varies somewhat after the startup - I had to adjust the pointing into the PMC a couple of times by ~1 full turn of the Polaris mount screws, but the IMC has been locked (mostly) for the last ~16 hours.

Quote:

I've checked the state of the laser interlock switch and everything looked normal.

  15508   Thu Aug 6 22:57:20 2020 gautamUpdatesafetyNew live HV Supplies

Be aware that there is now a KEPCO HV supply that is energized, sitting on the floor immediately adjacent to the OMC rack, east of the AP table. It is currently set to 100 V DC, and a PI PZT installed on the AP table has its 3 PZTs energized by said supply (via an OMC piezo driver). I will post pictures etc of the work from the last 10 days over the weekend.

  15544   Fri Aug 28 11:41:23 2020 gautamBureaucracysafetyCrane inspection 2020

Mr Fred Goodbar of Konacrane was in the lab 830am-1130am today. All three cranes in the VEA were inspected, loaded with 450lb test weights, and declared in good working condition and safe to use.

  1. Apparently, the clackity noise heard when running the crane at the south end is a known problem - the crane was opened up and inspected sometime in the past, and no obvious cause was found. This is not expected to affect the usability of the crane.
  2. The travel speed of the cranes is slow - but this is apparently intentional, on the request of Steve V.

The interferometer subsystems appear normal after the inspection. 

  15932   Wed Mar 17 15:02:06 2021 gautamUpdatesafetyDoor to outside from control room was unlocked

I came into the lab a few mins ago and found the back door open. I closed it. Nothing obvious seems amiss.

Caltech security periodically checks if this door is locked but it's better if we do it too if we use this door for entry/exit.

  15938   Thu Mar 18 12:35:29 2021 ranaUpdatesafetyDoor to outside from control room was unlocked

I think this is probably due to the safety tour yesterday. I beleive Jordan showed them around the office area and C&B. Not sure why they left through the control room.

Quote:

I came into the lab a few mins ago and found the back door open. I closed it. Nothing obvious seems amiss.

Caltech security periodically checks if this door is locked but it's better if we do it too if we use this door for entry/exit.

 

  8285   Wed Mar 13 11:34:24 2013 SteveUpdateoptical tablestable covers moved to CES

The two acrylic optical table enclosures were moved from the carpenter shop to CES. I need to order windows. The latest quotes from Laseroptik  are posted at the wiki / aux_optics page.

Things to do: order windows, draw and order window flange, install surgical tubing seals, buy and line enclosures with IR shield films.

Attachment 1: acrylicEnclosure.jpg
acrylicEnclosure.jpg
  8342   Mon Mar 25 18:58:09 2013 Albert YangUpdateoptical tablesOptical Table Toolboxes

For those of you who spend annoying amounts of time looking for tools, fear no more. Toolboxes for each optical table are coming!

They will probably have:

IR Viewer (a few optical tables will have IR viewers, these specific tables will be labeled in the diagram coming out later)

IR Card

Ball screw drivers (3/16 in.) 6-8 in. handle

SMA Wrench

Allen Keys

Flashlight

Various Connectors (I'll find out what's needed at some point)

Zip Ties

Small flat screwdrivers (for adjusting camera gains)

 

Please suggest what else may be needed in these boxes.

The boxes will be held to the side of the tables, either by magnets or screws. A diagram of where they will be placed on each optical table in order to minimize obstruction of walkways will be distributed soon. Any objections can then be noted.

  8382   Mon Apr 1 16:16:16 2013 AlbertUpdateoptical tablesOptical Table Toolboxes Update

A heavy duty plastic box is the likeliest candidate for the optical table toolbox. It measures 5 9/16 in. x 11 5/8 in. x 4 5/8 in. and fits all the tools comfortably. ( http://www.mcmaster.com/#plastic-bin-boxes/=m4yh4m  ,  under Heavy Duty Plastic Bin Boxes)

The list of tools has been updated to include a pen and a wire cutter as well as everything previously stated.

In addition, Steve has recommended that boxes should be secured to the walls or surfaces near the optical tables as opposed to the optical tables themselves, as to keep the tables from wobbling when tools are being exchanged.

A diagram of tentative box placements will go out soon.

  8384   Mon Apr 1 16:35:42 2013 AlbertUpdateoptical tablesOptical Table Toolboxes Update

Quote:

A heavy duty plastic box is the likeliest candidate for the optical table toolbox. It measures 5 9/16 in. x 11 5/8 in. x 4 5/8 in. and fits all the tools comfortably. ( http://www.mcmaster.com/#plastic-bin-boxes/=m4yh4m  ,  under Heavy Duty Plastic Bin Boxes)

The list of tools has been updated to include a pen and a wire cutter as well as everything previously stated.

In addition, Steve has recommended that boxes should be secured to the walls or surfaces near the optical tables as opposed to the optical tables themselves, as to keep the tables from wobbling when tools are being exchanged.

A diagram of tentative box placements will go out soon.

 I also took every allen key I can find so they can be sorted. They will be back in the appropriate drawer locations soon.

  8395   Tue Apr 2 21:11:42 2013 RanaUpdateoptical tablesOptical Table Toolboxes Update

Quote:

A heavy duty plastic box is the likeliest candidate for the optical table toolbox. It measures 5 9/16 in. x 11 5/8 in. x 4 5/8 in. and fits all the tools comfortably. ( http://www.mcmaster.com/#plastic-bin-boxes/=m4yh4m  ,  under Heavy Duty Plastic Bin Boxes)

The list of tools has been updated to include a pen and a wire cutter as well as everything previously stated.

In addition, Steve has recommended that boxes should be secured to the walls or surfaces near the optical tables as opposed to the optical tables themselves, as to keep the tables from wobbling when tools are being exchanged.

A diagram of tentative box placements will go out soon.

 No, the small boxes must be attached to the optical tables. They won't be heavy enough to change the table tilt.

Also, all tools must be color coded according to the optical table using the 3M Vinyl table color code:

http://www.3m.com/product/images/Vinyl-Electrical-Color-Tape-300.jpg

  8408   Wed Apr 3 19:01:06 2013 AlbertUpdateoptical tablesOptical Table Toolboxes Update

Quote:

Quote:

A heavy duty plastic box is the likeliest candidate for the optical table toolbox. It measures 5 9/16 in. x 11 5/8 in. x 4 5/8 in. and fits all the tools comfortably. ( http://www.mcmaster.com/#plastic-bin-boxes/=m4yh4m  ,  under Heavy Duty Plastic Bin Boxes)

The list of tools has been updated to include a pen and a wire cutter as well as everything previously stated.

In addition, Steve has recommended that boxes should be secured to the walls or surfaces near the optical tables as opposed to the optical tables themselves, as to keep the tables from wobbling when tools are being exchanged.

A diagram of tentative box placements will go out soon.

 No, the small boxes must be attached to the optical tables. They won't be heavy enough to change the table tilt.

Also, all tools must be color coded according to the optical table using the 3M Vinyl table color code:

http://www.3m.com/product/images/Vinyl-Electrical-Color-Tape-300.jpg

 Ok.

So the new tentative plan on the boxes is to bolt them (magnetic strips were proposed but overruled on the grounds that they're not strong enough to withstand being knocked down by accidents).

The boxes are going to be a mix of the Thorlabs Benchtop Organizer (http://www.thorlabs.com/thorProduct.cfm?partNumber=BT17) and the original box. The box will have a region covered in mesh, so tools can be placed and held there. The box will also have a spacer at the bottom, with another mesh right above it, lined up. However, this double-mesh will only cover half of the box. The other half of the box will be compartmentalized to hold things such as screws, connectors, etc. I will talk to Steve about building the boxes.

Also, using nail-polish to coat the Allen wrenches is not going to work. Nail polish does not stick easily enough. The tentative new plan is oil paint, but this is to be reviewed.

Finally, the diagram with the placement of the boxes relative to the optical tables has been put on paper, but needs to be computerized so it's easier to read. This will be done as soon as possible.

  8410   Wed Apr 3 23:22:20 2013 ranaUpdateoptical tablesOptical Table Toolboxes Update

 There are some tips for how to appy nail polish on YouTube from MKNails and MissJenFABULOUS. Their tips on how to prepare the site for a strong bonding strength are probably helpful for our gold/nickel coated tools. For chrome tools we may need to abrade the surface with a stone or fine sandpaper for it to take the layer better. IF the YouTube videos don't do it for you, then I suggest contacting Tom Evans at LLO to find out what kind of nail polish he uses.

  8445   Thu Apr 11 16:29:23 2013 AlbertUpdateoptical tablesOptical Table Toolboxes Update

Quote:

 There are some tips for how to appy nail polish on YouTube from MKNails and MissJenFABULOUS. Their tips on how to prepare the site for a strong bonding strength are probably helpful for our gold/nickel coated tools. For chrome tools we may need to abrade the surface with a stone or fine sandpaper for it to take the layer better. IF the YouTube videos don't do it for you, then I suggest contacting Tom Evans at LLO to find out what kind of nail polish he uses.

 This is the tentative box placement per optical table. The toolboxes are going to be color-coded by a combination of two colors (the order won't matter). The side of each toolbox will have a little panel to let you know which box corresponds to which set of colors.

On the diagram, the set of colors is simply the color of the box border and the color of the text.

If anyone has a problem with any of the colors or the box placement let me know before they are installed and become an annoyance:

Diagram.png

Box Placements:

ETMY: Box will be attached to the underside of the table by magnets. The box will be on the north side of the optical table.

POY: Box will be attached to the side of the optical table by magnets. The box will be on the west side of the optical table.

BSPRM: Box will be attached to the side of the optical table by magnets. The box will be on the west side of the optical table.

AS: Box will be attached to the side of the optical table by magnets. The box will be on the north side of the optical table.

PSL1: Box will be inside the optical table, in the northeast corner.

PSL2: Box will be inside the optical table, in the southwest corner.

POX: Box will be attached to the side of the optical table by magnets. The box will be on the south side of the optical table.

MC2: Box will be attached to the side of the optical table by magnets. The box will be on the south side of the optical table.

ETMX: Box will be attached to the side of the optical table by magnets. The box will be on the east side of the optical table.

  8457   Mon Apr 15 17:44:28 2013 AlbertUpdateoptical tablesOptical Table Toolboxes Update

I decided to go see what the electrical tape looks like on the other tools.

These are the tools I felt were necessary to label with tape: (the others don't seem to be terribly important in terms of not interchanging between boxes)

photo.JPG

On another note I'm not sure why electrical tape can't be used on the Allen Wrenches too.

I also plan on ordering smaller flash lights for each table (this one is bulky and unwieldy), and filling in the gaps of the Allen Wrench sets as soon as I get the go-ahead.

  8487   Wed Apr 24 18:51:12 2013 KojiConfigurationoptical tablesPD frequency response

The fibers should be routed beneath the electrical cables.
They should be fixed on the table for strain relieving.
The slack of the fibers should be nicely rolled and put together at the splitter side.

These are expected to be done next time when the fiber team work around the table.

We also expect to have the table photo every time the work of the day is finished.

  8502   Mon Apr 29 08:17:40 2013 AlbertUpdateoptical tablesOptical Table Toolboxes Update

Quote:

I decided to go see what the electrical tape looks like on the other tools.

These are the tools I felt were necessary to label with tape: (the others don't seem to be terribly important in terms of not interchanging between boxes)

photo.JPG

On another note I'm not sure why electrical tape can't be used on the Allen Wrenches too.

I also plan on ordering smaller flash lights for each table (this one is bulky and unwieldy), and filling in the gaps of the Allen Wrench sets as soon as I get the go-ahead.

 

  8505   Mon Apr 29 15:53:49 2013 AlbertUpdateoptical tablesOptical Table Boxes

Quote:

 

 Albert, our new undergrad work force received 40m specific- basic safety training last week. Please read and sign 40m procedures booklet.

 These are the tentative box placements. Roughly. I don't actually have the box finalized yet, but the box should be around that size.

AS1.jpg AS1

BSPRM.jpgBSPRM

ETMX.jpgETMX

ETMY.jpgETMY

MC2.jpgMC2

POX.jpgPOX

POY.jpgPOY

 

How do I perspective ._.

  1020   Thu Oct 2 16:44:28 2008 steveSummaryoplevsoptical levers
The idea is to push the UGF to 10 Hz of the TM oplev servos with quiet HeNe laser.
We measured good intensity noise of JDS 1103P in May 2007 and converted most of the TM oplevs to it.
The ITMs still have the noisy 670nm , 1 mW, diode lasers to begin with.
In order to get 1 mW power returning to the qpds I measured the power going to TMs
and returning on qpds ...so we can select the appropriate laser power for the conversion.

40m optical lever lasers:

HeNe laser JDS 1103P, 633nm, linear polarization 500:1,

ETMX: qpd 0.12 mw (4%) reflected of 3 mW,
ETMY: qpd 0.1o (3.8%) " 2.6
BS: qpd 0.02 ( 2.5%) " 0.8
PRM: qpd 0.01 (1.3%) " 0.75
SRM: qpd 0.08 (10%) " 0.8

Coherent 670 nm Diode Lasers VLM-tm, 0.95 mW, linear polarization 100:1,

ITMX: qpd 0.1 mW (11%) reflected back from TM of 0.9 mW
ITMY: qpd 0.04 (7%) " " 0.6

It seems that JDS HeNe laser 633 nm, linear polarization 500:1, 10 mW will do the job
  1245   Thu Jan 22 12:08:59 2009 peteUpdateoplevsoplev calibration
Following the procedure described in Royal Reinecke's 2006 SURF report, I've calibrated the ETMY yaw oplev DOF. The idea is to sweep the mirror tilt, measuring the transmitted cavity power and the oplev error signal. The cavity power can be related to the mirror tilt in radians following D. Anderson APPLIED OPTICS, Vol. 23, No. 17, 1984.

I've made a simple matlab script which spits out the final number; it calls Royal's perl script to do the sweep. I get 420 microrad/ct for ETMY yaw. In 2006 Royal got 250 microrad/ct. Could something have changed this much, or is one of us wrong? I'll double check my procedure and do the other arm cavity oplevs, and describe it in detail when I have more confidence in it.

Kakeru and I plan to extend this to handle the PRM, SRM, and BS. One script to rule them all.
  1247   Thu Jan 22 23:36:50 2009 peteHowTooplevsarm cavity oplev calibration
calibrated the y-arm oplevs. the procedure is contained in a matlab script. the whereabouts of this script will be revealed in a future log entry.

ITMYpit 140 microrad/ct
ITMYyaw 98 microrad/ct
ETMYpit 400 microrad/ct
ETMYyaw 440 microrad/ct (previous measurement gave 420 microrad/ct)

procedure:

1) Start with a single arm aligned and locked. Dither the mirror tilt in a DOF. Measure arm cavity power and oplev error signal. See the first attached plot.

2) Fit the plot to a gaussian and determine mu and sigma.

3) For a spherical ETM optic, the power in the cavity P(a), as a function of translational beam axis displacement a=R*sin(theta), is proportional to exp[-a^2/(2*x^2)] where x is the waist size (D. Anderson APPLIED OPTICS, Vol. 23, No. 17, 1984). The power as a function of mirror tilt in cts, P(tilt) is proportional to exp[-(tilt-mu)^2 /(2*sigma^2)]. So if R is the mirror radius then theta = arcsin(a/R) = arcsin[(1/R)*(tilt-mu)*x/sigma)].

4) Fit theta versus mirror tilt to get the calibration. See the second attached plot.

5) For a flat ITM optic, mirror tilt causes an angular displacement of the beam. The math for this case is given in Anderson.
Attachment 1: ETMYpitpower.png
ETMYpitpower.png
Attachment 2: ETMYpitcal.png
ETMYpitcal.png
  1249   Fri Jan 23 12:48:12 2009 KakeruUpdateoplevsarm cavity oplev calibration
I calibrated optlevs of x and y arm cavity, indipendently from Peter's work.

ITMX pit: 77 microrad/ct
ITMX yaw: 73 microrad/ct
ETMX pit: 280 microrad/ct
ETMX yaw: 263 microrad/ct

ITMY pit: 120 microrad/ct
ITMY yaw: 93 microrad/ct
ETMY pit: 280 microrad/ct
ETMY yaw: 270 microrad/ct

This result is similar to Royal's one (within 30% difference except for ETMX pit), but different from Peter's in ETMY.

The attached figure is the data and fitted curve of ITMX pit.
I took this data for 8s, with 4 Hz excitation.
Attachment 1: ITMX_pitch.png
ITMX_pitch.png
ELOG V3.1.3-