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  40m Log, Page 318 of 335  Not logged in ELOG logo
ID Date Author Type Category Subjectup
  866   Thu Aug 21 16:28:59 2008 steveConfigurationSAFETYsafety glasses required
I just opened the MOPA shutter so PA is warming up.

High power beam path is cleared and laser safety glasses required.
  1288   Tue Feb 10 10:48:48 2009 steveBureaucracySAFETYsafety glasses scanned
All 40m safety glasses are absorbent.
They were scanned by 180 mW  2mm spot size  of 1064 nm beam and  their  transmissions were measured
They showed no degradation.
UVEX 's  LOTG-YAG/CO2 glasses (fits over personal glasses) 11 pieces,
Glendale-XC by Bacou-Dalloz,  #1166218VLT68% , aerodynamic style, 7 pieces, (4 missing )
KG5- glasses , heavier- made out of glass, 3 pieces,
Thorlab's LG10, 1 piece
Old glasses by "Laser Glass" Nd-YAG, 2 pieces
Totaling 24
Atm.2  showing our muilty wavelength glasses of 1064 and 530 nm
Their transmittance for both wavelength were zero.
Note: if you have prescripton safety glasses I would like to scan it for you !



Attachment 1: sgscan1.png
Attachment 2: sgscan2.png
  4924   Thu Jun 30 17:24:46 2011 steveUpdateSAFETYsafety interlocks

Lightwave M126-1064-700 lasers  sn415  at east end of the Y arm and  sn201 at the AP table  are connected individually  to one each EMERGENCY LASER SHUT OFF SWITCH. 

Attachment 1: P1070949.JPG
Attachment 2: P1070948.JPG
  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.



  942   Thu Sep 11 14:27:53 2008 steveBureaucracySAFETYsafety training
Peter Kalmus received 40m specific safety training last week.
  1243   Thu Jan 22 08:34:10 2009 steveBureaucracySAFETYsafety training
Kakeru received 40m safety training yesterday.

He has no authorization to work alone in the high power beam path yet.
  3058   Wed Jun 9 10:31:13 2010 steveUpdateSAFETYsafety training

Nancy and Sharmila received introductory early bird surf safety training for the 40m lab.

  7285   Mon Aug 27 15:46:55 2012 SteveUpdateSAFETYsafety training

 Rijuparna Chakraborty and Elli Elenora King received 40m specific  basic safety training in the 40mLab

Attachment 1: IMG_1597.JPG
  7374   Wed Sep 12 11:33:49 2012 SteveUpdateSAFETYsafety training

Eric Quintero and Mike Jenson received 40m specific basic safety training.

  7467   Wed Oct 3 11:43:33 2012 SteveUpdateSAFETYsafety training

Den Martynov received 40m specific safety training.

  7559   Tue Oct 16 17:06:47 2012 SteveUpdateSAFETYsafety training

Ayaka Shoda, visiting graduate student received basic 40m specific safety training today

Attachment 1: IMG_1735.JPG
  7725   Mon Nov 19 15:58:02 2012 SteveUpdateSAFETYsafety training

Charles Blakemore  our new undergrad help received 40m specific safety training today.

  8241   Wed Mar 6 16:14:27 2013 SteveUpdateSAFETYsafety training

Chloe Ling, Max Horton and Annalisa Allocca have received basic 40m specific safety training.

Attachment 1: IMG_500.jpg
  8503   Mon Apr 29 08:22:57 2013 SteveUpdateSAFETYsafety training


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

  8670   Tue Jun 4 10:47:57 2013 SteveUpdatesafetysafety training

Our early bird surf student Gautem has received 40m specific basic safety training today.

  10007   Mon Jun 9 09:41:06 2014 steveUpdatesafetysafety training

2014 surf students Nichin and Akhil received 40m specific basic safety training last week.

Attachment 1: 2014surfs.jpg
  10138   Mon Jul 7 14:38:55 2014 SteveUpdatesafetysafety training

TaraV - geology major undergrad -  of Jenne's summer help received 40m specific basic safety training.

  10781   Thu Dec 11 15:40:04 2014 SteveUpdatesafetysafety training


 Katherine Dooley has received 40m specific basic safety training in the 40m lab

  11531   Tue Aug 25 16:39:06 2015 SteveUpdatesafetysafety training

Alessandra Marrocchesi received 40m specific basic safety training yesteday.

  11660   Fri Oct 2 15:33:09 2015 SteveUpdatesafetysafety training

Gautom has received 40m specific basic safety training today.

  11728   Wed Nov 4 08:04:53 2015 SteveUpdatesafetysafety training

Yutaro Enamoto, visiting graduate student of Seiji received 40m specific basic safety training.


Attachment 1: Yutaro.jpg
  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.


  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
  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
  13406   Mon Oct 30 08:08:06 2017 SteveUpdatesafetysafety training

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

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

Chub Osthelder received 40m specific basic safety traning today.

  488   Tue May 20 09:28:42 2008 steveBureaucracySAFETYsafety traning for 40m
Tara Chalernsongsak, new gradstudent for K. Libbrecht was introduced to the basics of the 40m operations.
  1273   Thu Feb 5 09:12:29 2009 steveBureaucracySAFETYsafety updates & fire alarm test

The fire alarm test was completed at 13:30 yesterday.


I updated the 40M Emergency Calling List by replacing Rob by Yoichy. The calling order: Vass,  Aso and Taylor.

Rana and Yoichy were added to the "Registered PSL Operator List"  and posted it in the lab. (not in the document, that should be up dated)

We are getting ready for the annual safety audit. It will be held next week  at 14:00 Friday, Feb 13, 2009

Please participate in the preparation by correcting it or just  tell me.


Rod Luna is organizing the pick up of the following old equipment:

HP laser jet  5000n, 3 of 19" 10 base-T network ports and  4 small hubs,

2 Sun monitors, 1 Viewsonic monitor, 7 keypads and

Hitachi scopes 2 of V-355, 2 of V-422, 1 of V-202 and 1 of V-6165



  1676   Tue Jun 16 03:43:04 2009 robUpdateLockingsame troubles

Lock is still being lost, right at the end of the process when trying to reduce the CARM offset to zero.

  6188   Thu Jan 12 07:44:21 2012 steveUpdateSUSsapphire wire standoff quote

On Tue, Dec 20, 2011 at 11:37 PM, Rana Adhikari wrote:

We are thinking of replacing a few metal parts in the suspension with sapphire/ruby. We want to replace the standoff (which is Al) with sapphire and also the top plate where the wire is clamped.

For the top, we should make a cutout for a little plate in the existing crossbar. In the cutout would go a little mounting plate. Then the clamping plate (which is now steel) we would also replace with a Sapphire one.

I don't think it matters whether its sapphire or ruby, just has to be very hard.

Can you please get some quotes on the parts?


Attachment 1: standoff.PDF
  13747   Wed Apr 11 10:47:26 2018 SteveUpdateSUSsatellite amps labeled

Satellite amplifiers labeled with date. Old labels left on.

Attachment 1: DSC00912.JPG
  8719   Wed Jun 19 00:46:06 2013 JenneUpdateSUSsave/restore alignment scripts now also work for TTs, fixed a bug

I have done a quick update of the IFO_ALIGN screen's save and restore scripts, so that we can now also save, restore, and view the saved values for the input tip tilts. 

In the past, there was an "if" statement to check if the optic was a PZT, and if so, define the alignment channels accordingly (since all the SOS suspensions have the same format for the name, and the PZTs were the odd ones out).  I have removed the mention of PZTs, and replaced the if statement with an "if TTs" statement, and put in the correct channel names (C1:IOO-TT#_PIT_OFFSET, and the same for YAW). 

Also, I caught a bug in the code, which explains some confusing behavior that I had seen in the past.  When deciding if the restore script should take small steps or just do a big step, it looked at the difference between the saved value and the current value of the slider.  It was *not* looking at the absolute value of the difference.  So, if you had misaligned a slider by hand, and it was in the opposite direction of what the misalign script does, the restore script wouldn't realize that the optic needed to be restored in small steps.  I have now fixed this bug for both pit and yaw cases of the restore script.

  6819   Fri Jun 15 00:50:54 2012 yutaUpdateGreen Lockingscanned Y arm for 5FSR

I scanned Y arm for 5FSR (below).
I could done this after I put a whitening filter.
Currently, whitening filter between the beatbox and AA filter is made of

  Ponoma blue box(passive filter with zero at 1 Hz, pole at 10 Hz) + SR560(flat gain 100)

I couldn't do more than 5FSR because SR560 overloads. I checked it by staring at the indicator during the scan.
Reason why we kept loosing lock last night was the overload of  SR560. Mystery solved!

Anyway, 5FSR is enough.
Our next step is to reduce residual arm length fluctuation.


Also, I increased the alingnment of IR. So, the higher order modes are less than the last scan.

  6820   Fri Jun 15 01:53:05 2012 KojiUpdateGreen Lockingscanned Y arm for 5FSR

Interesting. It seems for me that there is a dependence of the noisiness as the beat frequency is scanned.

As you increase (or decrease?) the offset, C1:ALS-BEATY-COARSE_I_IN1 becomes bigger and more crisp.
The resulting out-of-loop stability also seems to be improved as you can see from the crispness of the PDH signal.

Do you find why this happens? Is this because the beat S/N depends on the beat frequency due to the PD noise?


  6823   Sat Jun 16 12:03:41 2012 ZachUpdateGreen Lockingscanned Y arm for 5FSR

Is that time stamp really correct? I wanted to look at the signal closely to see if I could get any feeling for why it would look so different when positive vs. negative, but I do not see a triangle anywhere near this time (1023780144)...


Interesting. It seems for me that there is a dependence of the noisiness as the beat frequency is scanned.

As you increase (or decrease?) the offset, C1:ALS-BEATY-COARSE_I_IN1 becomes bigger and more crisp.
The resulting out-of-loop stability also seems to be improved as you can see from the crispness of the PDH signal.

Do you find why this happens? Is this because the beat S/N depends on the beat frequency due to the PD noise?



  6824   Sat Jun 16 13:01:17 2012 yutaUpdateGreen Lockingscanned Y arm for 5FSR


Is that time stamp really correct?

 Yes. I used pyNDS to get data, but here's a screenshot of dataviewer playing back 300 seconds from GPS time 1023780144.


  450   Fri Apr 25 15:44:21 2008 steveUpdatePSLscattering measurments
In pursuit of a low back scattering, high power beam dump we looked at materials such:
polished copper, polished aluminum, diamond cut aluminum, variety of polished & heat treated stainless steel and shades of black glasses.
Black glass is ideal at low power. Superpolished SS 304 #8 is the only material that measures close to bg
We are still looking for a conductive low back scattering material that would be ideal for a good high power beam trap.

Black glass-shade 12, ss304 superpolished #8 and white paper-B98-24lbs back scattering were compared at 1064 nm

Atm 1: data plot numbers from front panel of SR830 display,
sensitivity: 1x1 mV for bg and ss
1x1 V for wp

Atm 2: drawing of measurement set up
Atm 3: SR830 lock.amp settings
Atm 4: view from steering mirror
Atm 5: view from black glass trap
Atm 6: white paper
Attachment 1: scatmeas20080425.xls
Attachment 2: scattring_set_up_20080425.ppt
Attachment 3: sr830settings.pdf
Attachment 4: viewfmirror.pdf
Attachment 5: viewfbgtrap.pdf
Attachment 6: wpnmount.pdf
  5046   Wed Jul 27 15:18:50 2011 kiwamuSummaryGeneralschedule

The vent will start from 1 st of August ! !

  132   Wed Nov 28 16:46:28 2007 ranaConfigurationComputersscientific linux 5.0
I tried installing Scientific Linux on Tiramisu. The installation process was so bad (really)
that I quit after 15 minutes. Its back to booting Ubuntu as if nothing had ever happened. Let
us never speak of Scientific Linux again.
  9984   Wed May 21 13:51:19 2014 SteveUpdatesafetyscope battery recall

Tektronix RECALL on TDS3000 or TDS300B  oscilloscope BATTERIES TDS3BATB

This Lithium-Ion battery can be a fire hazard !  Remove battery pack and recycle it through Safety Office !

  71   Tue Nov 6 16:48:54 2007 tobinConfigurationComputersscopes on the net
I configured our two 100 MHz Tektronix 3014B scopes with IP addresses: (scope0) and (scope1). Let the scripting commence!

There appears to be a Matlab Instrument Control Toolbox driver for this scope.
  5159   Tue Aug 9 16:54:47 2011 steveUpdateVACscratch on vac door

Jenne found a big scratch on the north vac door of ITMY. Fortunately it does not reach the inner annulos 0 -ring seal.

This is precisely what we have to avoid to preserve our vacuum system!


Attachment 1: P1080152.JPG
  4373   Thu Mar 3 07:25:24 2011 kiwamuUpdateGreen Lockingscrewed up the end PDH box

 I somehow screwed up the PDH box at the X end station. 

Right now it's not working, so I am going to check and fix it today.


 In the last evening I found that one of the gain stages on the PDH box wasn't fully functional.

So I started investigating it and I though it was going to finish soon, but actually it wasn't so easy.


  The PDH box has several gain stages. So an input signal goes through a buffer, a filter, a boost and an output buffer stages sequentially.

The boost stage is supposed to have gain of 10, but I found it didn't have such gain.

In fact the gain was something like -30dB which is pretty small. Plus this boost stage was imposing an wired bump on the transfer function around 50 kHz.

I checked the voltages on some components around the boost stage and confirmed there were no strange voltage.

Then I suspected that the op-amp : LF356 had been broken for some reason. So I replaced it by LT1792 to see if it fixes the issue.

Indeed it did make it functional. However after few minutes of the replacement, it went back to the same bad condition.

I have no idea about what was going on at that time. Anyway it needs more careful investigations.


  I temporarily put a jumper cable on the board to skip this stage, but now the PDH lock is not healthy at all.

  4594   Mon May 2 11:14:27 2011 kiwamuUpdateSUSscript : opticshutdown

Just FYI.

There is a useful script for this particular job : shutting down all the suspensions and bringing it back to operation after 5 hrs.

It is called opticshudown, which resides in /cvs/cds/rtcds/caltech/c1/scripts/SUS/.


Also I added this script on the list in the wiki where all the scripts will be listed.


If you find any other useful scripts, please add them on the wiki.

Quote from #4592

I leave all the suspensions free from the watchdogs for 5 hours from now.


  110   Fri Nov 16 11:27:18 2007 tobinUpdateComputersscript fix
I added a tidbit of code to "LIGOio.pm" that fixes a problem with ezcastep on Linux. Scripts such as "trianglewave" will now work on Linux.
# On Linux, "ezcastep" will interpret negative steps as command line arguments,
# because the GNU library interprets anything starting with a dash as a flag.
# There are two ways around this.  One is to set the environment variable
# POSIXLY_CORRECT and the other is to inject "--" as a command line argument
# before any dashed arguments you don't want interpreted as a flag.  The former
# is easiest to use here:

if (`uname` =~ m/Linux/) {
    # Add an environment variable for child processes
  6727   Thu May 31 04:03:17 2012 yutaUpdateIOOscript for MC beam spot measurement

I wrote a wrapping script for measuring MC beam spot. We had to run several scripts for the measurement (see elog #6688), but now, you only need to run /opt/rtcds/caltech/c1/scripts/ASS/MC/mcassMCdecenter.

The measured data file will be stored in /opt/rtcds/caltech/c1/scripts/ASS/MC/dataMCdecenter/ directory, with a timestamp.
The calculated beam spot position data will be logged in /opt/rtcds/caltech/c1/scripts/ASS/MC/dataMCdecenter/logMCdecenter.txt file.
I had to edit sensemcass.m file, in order to write the result into the log file. In this way, we can keep track of the beam displacement.

Currently, the calculation script is written in the MATLAB file(sensemcass.m), which isn't very nice.
To run a MATLAB file from the command line
, you have to write something like this;

matlab -nodesktop -nosplash -r "sensemcass('./dataMCdecenter/MCdecenter201205210258.dat')"


  6871   Mon Jun 25 17:48:27 2012 yutaUpdateComputer Scripts / Programsscript for finding IR resonance using ALS

I made a python script for finding IR resonance using ALS. It currently lives in /opt/rtcds/caltech/c1/scripts/ALS/findIRresonance.py.

The basic algorism is as follows.

1. Scan the arm by putting an offset to the phase output of the phase tracker(Step C1:ALS-BEAT(X|Y)_FINE_OFFSET_OFFSET by 10 deg with 3 sec ramp time).

2. Fetch TR(X|Y) and OFFSET online data using pyNDS during the step.

3. If it finds a tall peak, sets OFFSET to the value where the tall peak was found.

4. If tall peak wasn't found, go back to 1 and step OFFSET again.

The time series data of how he did is plotted below.
I ran the script for Y arm, but it is compatible for both X and Y arm.


ELOG V3.1.3-