40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log, Page 73 of 341  Not logged in ELOG logo
ID Date Author Type Category Subjectdown
  7658   Thu Nov 1 19:28:48 2012 JenneUpdateAlignmentaligned, AS beam on camera

After everyone else did the hard work, I moved the AS first-on-the-table steering mirror sideways a bit so the AS beam is on the center of the mirror, then steered the beam through the center of the lens, onto the 2" 99% BS.  I also moved the camera from it's normal place (the 1% transmitted through that BS) to the AS110 PD path, as we did last vent.  We'll need to put it back before we go back to high power.

  4016   Mon Dec 6 22:18:39 2010 kiwamuUpdateGreen Lockingaligned the beam axis

 [Suresh and Kiwamu]

We aligned the green beam to the X arm cavity more carefully.

Now the green beam is hitting the centers of ETMX, ITMX and BS.

Also we confirmed that the green beam successfully comes out from the chamber to the PSL table.

 


(what we did)

- opened the BS, ITMX and ETMX chambers. 

- checked the positions of the beam spots on ITMX, BS and ETMX

   The spot position on ETMX was fine,

   But at BS and ITMX, the spots were off downward.

   We decided to move the beam angle by touching a steering mirror at the end green setup.

- changed the beam axis by touching the steering mirror at the end station.

- checked the spot positions again, they all became good. It looks the errors were within ~ 1mm.

- moved the position of a TT, which is sitting behind the BS, by ~10mm, because it was almost clliping the beam.

- aligned the green optics

- got the beam coming out from the chamber. 

 

 

  1327   Thu Feb 19 23:50:31 2009 peteUpdateLockingaligned pd's on AP table

Yoichi, Peter

While continuing our efforts to lock, we noticed the procedure failed at a point it had gotten past last night:  turning on the bounce/roll filters in MICH, PRC, and SRC.  We checked the MICH transfer function and noticed that the unity gain point was ~10 Hz, well below the bounce modes.   We tried increasing the gain but found saturation, and Rob suggested that there could be misalignment on the AP table, which Steve worked on today.  We went out and found two of the PDs (ASDD133 and AS166) to be badly misaligned probably due to a bumped optic upstream.  We re-aligned.

 

 

  6798   Tue Jun 12 01:58:33 2012 yutaUpdateGreen Lockingaligned Y arm to Y end green

[Jenne, Yuta]

We aligned Y arm to the Y end green incident beam.
We noticed two TEM00, bright and dim, so we decreased Y end laser temperature to 34.13 deg C.
It doubled the transmission of the green, and now the transmission to the PSL table is 178 uW, which is close to the maximum(197 uW) we got so far.

Current settings for Y end laser is;

  Y end laser "T+": 34.049 deg C
  Y end laser "ADJ": 0
  Y end laser measured temperature: 34.13 deg C
  C1:GCY-SLOW_SERVO2_OFFSET = 31025
  Y end slow servo: on (was off)

We aligned IR beam to the Y arm by mostly adjusting PZTs and got the transmission, C1:LSC-TRY_OUT ~ 0.9.

We tried to calculate the mode-matching ratio for IR by taking TRY data while ITMY and ETMY are swinging (without ALS), but it was difficult because we see too many higher order modes.

Tomorrow, we will (1) connect the beatbox to ADC, (2) edit c1gcv model, (3) scan the arm using I-Q signals.

  6713   Wed May 30 01:35:15 2012 yutaUpdateGreen Lockingaligned Y arm green beam

[Jenne, Yuta]

We aligned the Y arm for IR (C1:LSC-TRY_OUT is now ~ 0.9), and aligned the green beam from the ETMY table. The Y arm green is now resonating in TEM00 mode, but we need some monitors (green trans or green refl) to maximize the coupling.

We noticed that the MC beam spot are oscillating at ~ 1 Hz, mostly in YAW.  This wasn't observable before the PMC realignment (elog #6708). We should find out why and fix it.

  3929   Tue Nov 16 03:33:22 2010 yutaUpdateIOOaligned Faraday, beam reached SM just before PRM

(Koji, Yuta)

We aligned the Faraday after MC and we are now ready to install PRM.

Background:
  MC was roughly aligned (beam spot ~0.7mm from the actuation center).
  So, we started aligning in-vac optics.
  First thing to align was the Faraday after MC3.

What we did:
  1. Ran A2L.py for confirmation.(Second from the last measurement point on the A2L result plot)

  2. Aligned the Faraday so that MC3 trans can go through it. We moved the Faraday itself, while we didn't touch IM2.
     We turned the pitch nob of the last steering mirror at PSL table in CCW slightly in order to lower the beam at the Faraday by ~1mm.

  3. During the alignment, we found that the polarization of the incident beam was wrong. It should have been S but it was P.
     As there is the HWP right before the EOM, Rana rotated it so as to have the correct polarization of S on the EOM and the MC.
     Note that the PMC and the main interferometer are configured to have P-pol while the MC is to have S-pol.

  4. Setup the video camera to monitor the entrance aperture of the Faraday. It required 4 steering mirrors to convey the image to the CCD.

  5. Moved all of the OSEMs for MC1 and MC3 so that the sensor output can have roughly half of their maxima.

  6. Ran A2L.py. (The last measurement point on the A2L result plot)

  7. Aligned the IO optics so that the beam goes Faraday -> MMT1 -> MMT2 -> SM3.

Result:

  1. OSEM sensor outputs for MC1 and MC3 are;

(V) MC1 MC3
max current value max current value
ULSEN 1.3 0.708 1.37 0.699
URSEN 1.4 0.845 1.71 0.796
LRSEN 1.45 0.743 1.77 0.640
LLSEN 1.56 0.762 1.56 0.650
SDSEN 1.67 0.801 1.59 0.821



  2. A2L result is;
MCalignNov16.png


     The beam position slightly got lower(~0.2mm), because we touched SM at PSL table.
     Alignment slider values changed because we moved MC1 and MC3 OSEMs.

  3. Now, MC_RFPD_DCMON is ~0.39 when MC unlocked and ~0.083 when locked.
     So, the visibility of MC is ~79% (for S-pol).

  4. Now the incident beam to the MC has S polarization, the cavity has higher finesse. This results the increased MC trans power.
     It was ~8e2 when the polarization was P, now it is ~4.2e3 when the MC is locked.

  5. The beam reached SM3 at BS table. The alignment of the SM2, MMT1, MMT2 were confirmed and adjusted.

  6. All pieces of the leftover pizza reached my stomach.

Plan:
  - Install PRM to the BS chamber.
  - Align PRM and get IFO reflection beam out to the AP table
 

  9080   Wed Aug 28 06:17:15 2013 manasaUpdateComputer Scripts / Programsalias for MATLAB2010

Although Matlab 2013 has not been causing any visible trouble so far, it takes a while to startup.

I have added alias 'ml10' to bash to start Matlab 2010 from the terminal for convenience.

  106   Thu Nov 15 18:06:06 2007 tobinUpdateComputersalex: linux1 root file system hard disk's dying
I just noticed that Alex made an entry in the old ilog yesterday, saying: "Looks like linux1 root filesystem hard drive is about to die. The system log is full of drive seek errors. We should get a replacement IDE drive as soon as possible or else the unthinkable could happen. 40 Gb IDE hard drive will be sufficient."
  3541   Tue Sep 7 23:49:08 2010 sanjitConfigurationComputersaldabella network configuration

 

added name server 192.169.113.20 as the first entry in /etc/resolv.conf

changed the host IPs in /etc/hosts to 192.168.xxx.yyy

made:

127.0.0.1 localhost.localdomain localhost

::1 localhost6.localdomain6 localhos6

as the first two lines of /etc/hosts

 

/cvs/cds mounts

on ethernet, DNS look-up works without the explicit host definitions in /etc/hosts,

but those entries are needed for wifi only connection.

 

  3623   Wed Sep 29 18:28:32 2010 yutaUpdateComputersaldabella connects to the wireless network

Background:
 We need laptops that connect to the wireless network to use them in the lab.

aldabella:
 Dell Inspiron E1505 laptop
 Broadcom Corporation BCM4311 802.11b/g WLAN (rev 01) (PCIID: 14e4:4311 (rev 01))

What I did:
1. I followed this method(Japanese!): http://www.linuxmania.jp/wireless_lan.html
 Except I installed ndiswrapper-1.56 and cabextracted sp32156.exe.
  http://sourceforge.net/apps/mediawiki/ndiswrapper/index.php?title=Broadcom_BCM4311
 Also, I didn't run
  # ndiswrapper -m

2. Then I did step #6 in here: http://nodus.ligo.caltech.edu:8080/40m/1275
 Note that the hardware is eth1 instead of wlan0.

3. Added the following line to /etc/rc.d/rc.local to make ndiswrapper load on every boot:
 /sbin/modprobe ndiswrapper

Result:
 aldabella now connects to the wireless martian network on every boot!!

Note:
 Somehow, the method that uses Broadcom official driver doesn't work.
  http://wiki.centos.org/HowTos/Laptops/Wireless/Broadcom
 It returns the following error when activating eth1:
  Error for wireless request "Set Encode" (8B2A) :
    SET failed on device eth1 ; Invalid argument.
  Error for wireless request "Set Encode" (8B2A) :
    SET failed on device eth1; Invalid argument.

  2831   Thu Apr 22 09:03:54 2010 steveOmnistructurePEMaircondition can not be turned off

Koji and I wanted to turn off the IFO-room AC so the wind would not blow on MC1-3. We could not. The switches were probably bypassed when the power transformer was replaced at the last scheduled power outage.

  200   Wed Dec 19 11:31:01 2007 steveOmnistructurePEMaircond filter maintenance
Jeff is working on all air condiontion units of the 40m lab
This we do every six months.
  3297   Tue Jul 27 11:43:24 2010 steveUpdatePEMair quality is bad today

The lab is at 30,000 and Pasadena air is at 1.1 e+6 particles /cf min of 0.5 micron.

  13046   Wed Jun 7 10:07:00 2017 SteveUpdatePEMair condition thermostate

The Y arm ac thermostate was calibrated after cooling water relay replacement by Mike.... yesterday. The set temp is remaind to be 70F

The east end south wall temp is reading 22C

  3192   Mon Jul 12 10:23:51 2010 steveUpdatePEMair condition maintenance is today

The AC filters will be checked and/or replaced today. This means the AC will be off for sort periods of time. Temperature and particle count will be effected some what.

See 800 days plot

  12712   Fri Jan 13 14:18:28 2017 SteveUpdatePEMair condition fixed

The old control room AC  has been stick in heating mode for about 2 months. It's thermostate and fan belt  was finally replaced. It was calibrated and set to 71 F ( just behind 1X6 on west wall ) around 1pm.

Out belt; sad inside 

at 4 pm Rana cried

It must be too tight.

  1347   Tue Mar 3 08:44:31 2009 steveUpdatePEMair cond. maintenance today
IFO room 104 air conditions will be shut down for maintenance today.
This should be finished by noon.
The temperature and particle count variation can be more than usual.
  2972   Mon May 24 07:53:57 2010 steveConfigurationPEMair cond. just turned ON

IFO room temp 27.5C , Please remember to turn AC back on !

  8219   Mon Mar 4 11:30:47 2013 SteveUpdatePEMair cond problem

 

 The air cond is out of order at the area covered by racks 1 X 1  through 1 X 7

The arm X and Y AC units are working.

  7744   Mon Nov 26 10:58:20 2012 SteveUpdatePEMair cond maitenance tomorrow

Air conditioning maintenance is scheduled for tomorrow morning till noon.

  8314   Wed Mar 20 08:59:24 2013 SteveUpdatePEMair cond maitenance is today

 Outside air quality at 8:30am  1.1 million of 0.5 micron particles cf / min with MET counter #2

AC unit output measured  directly at the outlet of east end  6,000  and south end 3,000 of 0.5 micron particles cf / min with counter #2

Lab measurement at the top of IOOC 20K of 0.5 micron particles cf / min with MET #1

HEPA filters: 2 mobile units  at the middle of the east arm at speed 100%, PSL enclosure 20% and south end flow bench are running.

The PSL, south flow bench and mobile unit (Envirco  sn69406003 ) measured zero counts of 0.5 & 0.3 micron particles

Envirco HEPA filter unit sn 69406001 measured 50 particles of 0.5micron and 320 of 0.3 micron particles cf / min with counter #2

This filter will be replaced.

                   

NOTE: inside air quality peaks we can not control. It depends on the weather and our house keeping.

When your work is particle sensitive keep your eyes on the particle counter.

 

 

 

 

  10761   Mon Dec 8 09:03:49 2014 steveUpdatePEMair cond maintenance tomorrow morning

 

 AC maintenance is scheduled from 8am till 11am tomorrow morning.

  10773   Wed Dec 10 14:26:13 2014 steveUpdatePEMair cond maintenance and particle plot

Quote:

 

 AC maintenance is scheduled from 8am till 11am tomorrow morning.

 IFO air condition maintenance will continue tomorrow morning and it should be finished by 11:30AM

 We have new guys taking over this job: Sal and Chris so it takes longer. The units will be shut down for a bit.

They will not enter the IFO lab. The CES housed units will be worked on.

  5407   Wed Sep 14 15:05:52 2011 steveUpdatePEMair cond maintenance

Jeff has changed our AC filters inside the lab this morning. Now he is checking on the main filters at CES.  He will finish the roof units tomorrow.

Met One #1 counter is on the top of IOO chamber.  It is measuring 1 and 0.5 micron size particles.  One year of lab condition plot below.

 

  6754   Tue Jun 5 14:17:14 2012 steveUpdatePEMair cond maintenance

 

 Air conditioning maintenance is scheduled for tomorrow from 8 to 11am

  6782   Thu Jun 7 09:52:05 2012 steveUpdatePEMair cond maintenance

Quote:

 

 Air conditioning maintenance is scheduled for tomorrow from 8 to 11am

 Jeff checked and  replaced filters  as needed. Job completed this morning.

  13895   Tue May 29 16:33:04 2018 SteveUpdatePEMair cond filters replaced

Chris replaced some air condition filters and ordered some replacement filter today.

Quote:

 

Quote:

 

Quote:

Yesterday morning was dusty. I wonder why?

The PRM sus damping was restored this morning.

Yesterday afternoon at 4 the dust count peaked 70,000 counts

Manasa's alergy was bad at the X-end yesterday. What is going on?

There was no wind and CES neighbors did not do anything.

Air cond filters checked by Chris. The 400 days plot show 3 bad peaks at 1-20, 2-5 & 2-19

 

  11259   Mon Apr 27 09:09:15 2015 SteveUpdatePEMair cond filters checked

 

Quote:

 

Quote:

Yesterday morning was dusty. I wonder why?

The PRM sus damping was restored this morning.

Yesterday afternoon at 4 the dust count peaked 70,000 counts

Manasa's alergy was bad at the X-end yesterday. What is going on?

There was no wind and CES neighbors did not do anything.

Air cond filters checked by Chris. The 400 days plot show 3 bad peaks at 1-20, 2-5 & 2-19

  2156   Wed Oct 28 14:39:10 2009 steveUpdatePEMafter the tour of the 40m
Illuminators and PSL lights turned off.
HEPA filter speed increased from 20 to 100%
  11705   Wed Oct 21 10:03:15 2015 SteveUpdateVACafter running out of N2

 

Quote:

[ericq, Gautam, Steve]

Following roughly the same procedure as ELOG 11354, c1vac1 and c1vac2 were rebooted. The symptoms were identical to the situation in that ELOG; c1vac1 could be pinged and telneted to, but c1vac2 was totally unresponsive. 

The only change in the linked procedure was that we did not shut down the maglev. Since I unwittingly had it running for days without V4 open while Steve was away, we now know that it can handle shorter periods of time than that...

Upon reboot, many channels were readable again, unfortunately the channels for TP2 and TP3 are still blank. We were able to return to "Vacuum normal state," but because of unknowned communication problems with VM1's interlock, we can't open VM1 for the RGA. Instead we opened VM2 to expose the RGA to the main IFO volumn, but this isn't part of the "Normal" state definite, so things currently read "Undefined state".

Precondition:

1, Pressure gauges had no communication ( NO COMM ) with c1vac2

 

2, Lost N2 supply on Oct 9 This triggered a normal all valve closed condition. At this point you replace N2 cylinders and manually swich valves to recreate VAC NORMAL configuration in the correct sequential order.

   The very last thing you do is open V1 gate valve.

   a, check TP2 that is the forepump of the Maglev. Foreline pressure to drypump  ~ 10- 100 mTorr, rotation speed 50 Krpm

   b, open V4 if P2 <1Torr

   c, check Maglev rotating at 560 Hz

   d, open V1 if P1 <500 mTorr

   e, check TP3 foreline, rotation speed and open V5 if P3 <1 Torr with VA6 closed

   f, open VA6 if PAN <1 Torr

  g, open annulos valves one by one , like VASE if PASE <1 Torr and so on...........Now the Current State: should read Vac Normal

 

3, Maglev run for 7 days with V4 closed. This encreased its foreline pressure to estimated few Torrs  and its body temp rose ~30C on the outside.

   So it was sweating and it may be back streamed.

The present RGA data is indicating that it had to be very mild.

The RGA will have better sensitivity with VM1 open and VM2 closed.

The PSL output shutter stayed open during these period is pointing  to IFO pressure stayed P1 <3 mTorr

PROBLEM: P1 and P2 plot should show nothing where there is no communication.http://nodus.ligo.caltech.edu:8080/40m/151016_182003/oct16Fpm2015.png

                   How do we check if pressure based software interlocks are working in this no communication condition?

  9343   Tue Nov 5 08:44:21 2013 SteveUpdateIOOafter last steering mirror mount swap

 The IOO Angle and IOO Position qpds  were recentered after this entry.

 Suggested corrections in elog entry #9323 are completed:

 1,  last steering mirror mount replaced by Polanski mount

 2,  PSL output shutter mount reconfigured

 IOO qpds are not centered. I failed to connect laptops to 40MARSian network.

  2682   Thu Mar 18 15:33:17 2010 kiwamuSummaryElectronicsadvantege of our triple resonant EOM

In this LVC meeting I discussed about triple resonant EOMs with Volker who was a main person of development of triple resonant EOMs at University of Florida.

Actually his EOM had been already installed at the sites. But the technique to make a triple resonance is different from ours.

They applied three electrodes onto a crystal instead of one as our EOM, and put three different frequencies on each electrode.

For our EOM, we put three frequencies on one electrode. You can see the difference in the attached figure. The left figure represents our EOM and the right is Volker's.

Then the question is; which can achieve better modulation efficiency ?

Volker and I talked about it and maybe found an answer,

 We believe our EOM can be potentially better because we use full length of the EO crystal.

This is based on the fact that the modulation depth is proportional to the length where a voltage is applied onto.

The people in University of Florida just used one of three separated parts of the crystal for each frequency.

  2683   Thu Mar 18 19:00:04 2010 KojiSummaryElectronicsadvantege of our triple resonant EOM

Did you find what is the merit of their impedance matching technique?

Quote:

In this LVC meeting I discussed about triple resonant EOMs with Volker who was a main person of development of triple resonant EOMs at University of Florida.

Actually his EOM had been already installed at the sites. But the technique to make a triple resonance is different from ours.

They applied three electrodes onto a crystal instead of one as our EOM, and put three different frequencies on each electrode.

For our EOM, we put three frequencies on one electrode. You can see the difference in the attached figure. The left figure represents our EOM and the right is Volker's.

Then the question is; which can achieve better modulation efficiency ?

Volker and I talked about it and maybe found an answer,

 We believe our EOM can be potentially better because we use full length of the EO crystal.

This is based on the fact that the modulation depth is proportional to the length where a voltage is applied onto.

The people in University of Florida just used one of three separated parts of the crystal for each frequency.

 

  6941   Mon Jul 9 05:02:58 2012 yutaUpdateLockingadjusted ALS filters, current RMS

I adjusted filters of ALS to give more phase margin.
RMS of stabilized X/Y arm length is 97 pm and 65 pm respectively.

X arm ALS:
- Openloop transfer function
UGF ~160 Hz, phase margin 30 deg
1600 usec delay (LSC-XARM had 1800 usec delay)     500 usec delay (LSC-XARM had 570 usec delay) - Edited by Yuta on July 9

ALSXarmOLTF.png

- Arm length spectra
   Red is the free run spectrum. Measured using C1:ALS-BEATX_FINE_PHASE_OUT. Calibration factor is 1.32 nm/deg.
   Green is the out-of-loop spectrum. Measured using C1:LSC-POX11_I_ERR. Calibration factor is 3.8e12 counts/m.
   Blue is the in-loop spectrum. Measured using C1:ALS-BEATX_FINE_PHASE_OUT.
   Black is the expected spectrum from openloop transfer function, such as (free run)/|1+G|.
ALSXarmLengthspectra20120708.png


   Out-of-loop estimation of RMS during X ALS is 97 pm.
   RMS mostly comes from 1 Hz and 3.3 Hz peak.
   Out-of-loop and in-loop agrees at around 10-20 Hz.

Y arm ALS:
- Openloop transfer function
UGF ~130 Hz, phase margin 20 deg
2400 usec delay (LSC-XARM had 1800 usec delay)     760 usec delay (LSC-XARM had 570 usec delay) - Edited by Yuta on July 9

ALSYarmOLTF.png

- Arm length spectra
   Red is the free run spectrum. Measured using C1:ALS-BEATY_FINE_PHASE_OUT. Calibration factor is 1.30 nm/deg.
   Green is the out-of-loop spectrum. Measured using C1:LSC-POY11_I_ERR. Calibration factor is 1.4e12 counts/m.
   Blue is the in-loop spectrum. Measured using C1:ALS-BEATY_FINE_PHASE_OUT.
   Black is the expected spectrum from openloop transferfunction, such as (free run)/|1+G|.
ALSYarmLengthspectra20120708.png

   Out-of-loop estimation of RMS during X ALS is 65 pm.
   RMS mostly comes from 1 Hz and 3.3 Hz peak.
   Out-of-loop and in-loop agrees at around 3-40 Hz.

  14255   Mon Oct 15 12:52:54 2018 yukiUpdateComputer Scripts / Programsadditional comments
Quote:

but there's one weirdness: It get's the channel offset wrong. However this doesn't matter in our measurement because we're subtracting the dark level, which sees the same (wrong) offset.

When you do this measurement with oscilloscope, take care two things:

  1. set y-range of scope as to every signal fits in display: otherwise the data sent from scope would be saturated.
  2. set y-position of scope to the center and don't change it; otherwise some offset would be on the data.
  4019   Tue Dec 7 12:12:40 2010 kiwamuUpdateCDSadded some more DAQ channels

[Joe and Kiwamu]

We added some more DAQ channels on c1sus.

We wanted to try diagonalizing the input matrices of the ITMX OSEMs because the motion of ITMX looked noisier than the others

So for this purpose we tried adding DAQ channels so that we can take spectra anytime.

After some debugging, now they are happily running.

 


(DAQ activation code)

There is a code which activates DAQ channels written by Yuta in this October.

       /cvs/cds/rtcds/caltech/c1/chans/daq/activateDAQ.py

If you just execute this code, it is supposed to activate the DAQ channels automatically by editing C1AAA.ini files.

However there were some small bugs in the code, so we fixed them.

Now the code seems fine.

 

(reboot fb DAQ process)

When new DAQ channels are added, one has to reboot the DAQ process running on fb.

To do this, log in to a certain port on fb,

          telnet fb 8088

     shutdown

Then the process will automatically recover by itself.

After doing the above reboo job, we found tpman on C1IOO got down.

We don't fully understand why only C1IOO was affected, but anyway rebooting of the c1ioo front end machine fixed the problem.

 

  7067   Wed Aug 1 11:50:49 2012 JamieUpdateCDSadded input monitors to LSC_TRIGGER library part

I added an EPICS monitor to the input of the LSC_TRIGGER part, to allow monitoring the signal used for the trigger.  I then added the monitors to the C1LSC_TRIG_MTRX screen (see below).  This should hopefully aid in setting the trigger levels.

  624   Wed Jul 2 15:14:42 2008 steveUpdateGeneraladded beam traps
I placed baked razor beam trap after INJ_SM1 and flipper in the injection path on the AP table


Quote:
I have constructed the beam injection optics for the abs length measurement.

The injection beam was coarsely aligned to the interferometer. The reflected beam from SRM was already seen at AS CCD.
I have attached the optical configration for this measurement and the optics layout at the AP table.

I am going to go to LHO for three weeks. During the absence Alberto tunes the mode matching and the alignment of the interferometer.

In the process of making this report, I noticed that one of the iris apertures is about disturbing the beam for OMCR CCD. I will check this before I go to Hanford. Also an RF spectrum analyzer is at the AP table. I try to return this near the PSL on Monday morning.

Attachment 1: Optical configuration for the abs length measurement.
1) One of the arms is locked to the PSL beam by the main control system (red).
2) A laser beam is injected from the AS port (blue). This laser essentially has different frequency from that of PSL.
3) The injected beam and the outgoing PSL beam appear at the output of the faraday in the injection system.
4) They beat each other at the frequency difference of those two lasers.
5) A PLL is used to lock the frequency difference to a local oscillator (LO).
6) The LO frequency is swept at around 3.87MHz, that is the approximate FSR frequency of the arm cavity.
7) If the LO frequency hits the FSR within the resonant width, the beating also appears at the transmitted light as the injected beam also becomes resonant to the arm cavity.
8) Amplitude of the beating at the transmitted light is measured by a RF spectrum analyzer as a function of the LO frequency. We get the FSR frequency (= the arm cavity length) from the top of the resonance.

Attachment 2: Optics at the AP table for the laser injection
700mW NPRO, laser source. vertically polarized.
Periscope, to raise the beam 1 inch to make the beam at the 4 inch elevation.
INJ_SM1/INJ_SM2, steering mirrors to align the injection beam to the IFO beam.
HWP1, half wave plate to make the beam to the farady horiz-polarized. nominal 42deg on the readout.
FI, Faraday isolator for protection of the NPRO from the returning light, for obtaining the returning light.
HWP2, to make the beam from the Faraday horiz-polarized. nominal 357deg on the readout.
MM_Lens, f=125mm to match the laser mode to the IFO beam.
SM1/SM2, steering mirrors to align the IFO beam to the Farady Isolator.
IRIS1/IRIS2, for the coarse alignment of the injection beam.
FLIP, flipper mount to turn on/off the injection optics.

Alignment procedure of the injection system
0) Ignite NPRO several hours before the experiment so that the laser frequency can be stable.
1) Turn up FLIP. Close the shutter of NPRO.
2) Adjust SM1/SM2 so that the ifo beam can appear at the output of FI.
3) Adjust height and position of IRIS1/IRIS2 with regard to the ifo beam so that the ifo beam goes through IRIS1/IRIS2 even when they are closed.
4) Turn down FLIP. Open the shutter of NPRO.
5) Adjust INJ_SM1/INJ_SM2 so that the injection beam can go through IRIS1/IRIS2 even when they are closed.
6) At this time, it is expected that the reflection of the injection beam from SRM appears at AS CCD, if SRM is aligned.
7) Adjust INJ_SM1/INJ_SM2 so that the injection beam at AS CCD can overlap to the IFO beam.
8) Confirm the beam at the output of the FI also overlaps.
---- We are here ----
9) Change the ifo configuration to the X or Y arm only.
10) Scan the crystal temperature of the 700mW NPRO in order to try to have the beating of the two beams at the PD. AS OSA may be useful to obtain the beating.
11) Once the beating is obtained, adjust INJ_SM1/INJ_SM2 such that the beating amplitude is maximized.
  4420   Mon Mar 21 18:34:10 2011 kiwamuUpdateGreen Lockingadded a new ADC channel on 1X9

I added a new ADC channel for a DC signal from the X end green PD.

It is called C1:GCX-REFL_DC and connected to adc_0_1, which is the second channel of ADC_0.

 

By the way, when I tried connecting it to an ADC I found that most of the channels on the AA board on 1X9 were not working.

Since the outputs form the board are too small the circuits may have benn broken. See the picture below.

In addition to that  I realized that the signal from the PDH box for the temperature actuation is limited by +/- 2V due to the range of this AA board.

In fact the signal is frequently saturated due to this small voltage range.

We have to enlarge the range of this AA board like Valera did before for the suspensions (see this entry).

aa_board_1X9.jpg

  6372   Wed Mar 7 13:30:17 2012 JimUpdatePEMadded TPs and JIMS channels to PEM front-end model

[Jim Ryan]

The PEM model has been modified now to include a block called 'JIMS' for the JIMS(Joint Information Management System) channel processing. Additionally I added test points inside the BLRMS blocks that are there. These test points are connected to the output of the sqrt function for each band. I needed this for debugging purposes and it was something Jenny had requested.

The outputs are taken out of the RMS block and muxed, then demuxed just outside the JIMS block. I was unable to get the model to work properly with the muxed channel traveling up or down levels for this. Inside the JIMS block the information goes into blocks for the corresponding seismometer channel.

For each seismometer channel the five bands are processed by comparing to a threshold value to give a boolean with 1 being good (BLRMS below threshold) and 0 being bad (BLRMS above threshold). The boolean streams are then split into a persistent stream and a non-persistent stream. The persistent stream is processed by a new library block that I created (called persist) which holds the value at 0 for a number of time steps equal to an EPICS variable setting from the time the boolean first drops to zero. The persist allows excursions shorter than the timestep of a downsampled timeseries to be seen reliably.

The EPICS variables for the thresholds are of the form (in order of increasing frequency):

C1:PEM-JIMS_GUR1X_THRES1

C1:PEM-JIMS_GUR1X_THRES2

etc.

The EPICS variables for the persist step size are of the form:

C1:PEM-JIMS_GUR1X_PERSIST

C1:PEM-JIMS_GUR1Y_PERSIST

etc.

I have set all of the persist values to 2048 (1 sec.) for now. The threshold values are currently 200,140,300,485,340 for the GUR1X bands and 170,105,185,440,430 for the GUR1Y bands.

The values were set using ezcawrite. There is no MEDM screen for this yet.

PEM model was restarted at approx. 11:30 Mar. 7 2012 PST.

 

  16870   Tue May 24 10:37:09 2022 TegaUpdateVACadded FRG channels to slow channel ini file

[Vacuum gauge sensors]

Paco informed me that the FRG sensor EPICS channels are not available on dataviewer, so I added them to slow channels ini file (/opt/rtcds/caltech/c1/chans/daq/C0EDCU.ini). I also commented out the old CC1, CC2, CC3 and CC4 gauges. A service restart is required for them to become available but this cannot be done right now because it would adversely affect the progress of the upgrade work. So this would be done at a later date.

Quote:

git repo - https://git.ligo.org/40m/vac

Finally incorporated the FRGs into the main modbusIOC service and everything seems to be working fine. I have also removed the old sensors (CC1,CC2,CC3,CC4,PTP1,IG1) from the serial client list and their corresponding EPICS channels. Furthermore, the interlock service python script has been updated so that all occurrence of old sensors (turns out to be only CC1) were replaced by their corresponding new FRG sensor (FRG1) and a redundnacy was also enacted for P1a where the interlock condition is replicated with P1a being replaced with FRG1 because they both sense the main volume pressure.

 

  780   Fri Aug 1 11:51:15 2008 justingOmnistructureComputersadded /cvs/cds/site directory
I added a /cvs/cds/site directory. This is the same as is dicsussed here. Right now it just has the text file 'cit' in it, but eventually the other scripts should be added. I'll probably use it in the next version of mDV.
  2462   Mon Dec 28 23:56:44 2009 kiwamu, ranaUpdateComputersadd the HILO drift channels to the burt

The HIGH and LOW channels are added into the burt request file "/target/c1losepics/autoBurt.req".

These values are used to colorize the alarm texts in the "C1DRIFT_MONITOR.adl" like a threshold. (the screenshot attached)

Hereafter these values will be automatically restored by the burt.  Happy !

  16999   Wed Jul 13 13:30:48 2022 YehonathanUpdateBHDadd Laser RIN to MICH budget

the main laser noise coupling for a Michelson is because of the RIN, not the frequency noise. You can measure the RIN, in MC trans or at the AS port by getting a single bounce beam from a single ITM.

  17013   Mon Jul 18 16:49:57 2022 YehonathanUpdateBHDadd Laser RIN to MICH budget

I measured the RIN by taking the spectrum of C1:MC_TRANS_SUMFILT_OUT and dividing it by the mean count on that channel (~13800 cts). Attachment 1 shows the result.

I updated the MICH AS55 noise budget but got a very low contribution (gold trace in attachment 2).

It seems too low I think. What could've gone wrong? Finesse calculates that the transfer function from laser amplitude modulation to AS55 is ~ 1.5e-9 at DC. If I turn off HOMs I get 1e-11 at DC, so this coupling is a result of some contrast defect. Should I include some RMS imbalances in the optics to account for this? Should I include it as a second-order effect due to MICH RMS deviation from zero crossing?

Quote:

the main laser noise coupling for a Michelson is because of the RIN, not the frequency noise. You can measure the RIN, in MC trans or at the AS port by getting a single bounce beam from a single ITM.

 

  17015   Mon Jul 18 18:33:38 2022 KojiUpdateBHDadd Laser RIN to MICH budget

You should measure the coupling by noise injection. Noise budgeting does not need any modeling:

1) Measure the power spectrum density of the target signal (i.e. DARM) and the source noise (i.e. RIN this case)

2) Calibrate both using a calibration peak to convert 1) into the physical units (m/rtHz, 1/rtHz, etc)

3) Measure the transfer function from source to target using the noise injection. (i.e. RIN injection this case and look at the injection to RIN and injection to DARM)

4) Measure open-loop transfer functions if necessary. (i.e. DARM control open-loop transfer function to convert the error signal into the free running noise level)

Primarily, these are measured noise levels and noise couplings there is no room to involve a model there.
Once the noise budget was done, you can compare it with the model and say "the coupling is big/small/comparable".
 

Also, why don't you use C1:MC_TRANS_SUMFILT_IN1_DQ instead? Your _OUT signal seems affected by the bunch of comb notch filters to artificially remove the 60Hz harmonics. It's not a fair RIN measurement.

  15882   Mon Mar 8 20:11:51 2021 ranaFrogsComputer Scripts / Programsactivate_matlab out of control on Megatron

there were a zillion processes trying to activate (this is the initial activation after the initial installation) matlab 2015b on megatron, so I killed them all. Was someone logged in to megatron and trying to run matlab sometime in 2020? If so, speak now, or I will send the out-of-control process brute squad after you!

  5143   Mon Aug 8 19:45:27 2011 jamieUpdateCDSactivateDQ script run; SUS channels being acquired again

> Also the BS is missing its DAQ channels again (JAMIE !) so we can't diagnose it with the free swinging method.

I'm not sure why the BS channels were not being acquired.  I reran the activateDQ script, which seemed to fix everything.  The BS DQ channels are now there.

I also noticed that for some reason there were SUS-BS-ASC{PIT,YAW}_IN1_DQ channels, even though they had their acquire flags set to 0.  This means that they were showing up like test point channels, but not being written to frames by the frame builder.  This is pretty unusual, so I'm not sure why they were there.  I removed them.

  4241   Wed Feb 2 15:07:20 2011 josephbUpdateCDSactivateDAQ.py now includes PEM channels

[Joe, Jenne]

We modified the activateDAQ.py script to handle the C1PEM.ini file (defining the PEM channels being recorded by the frame builder) in addition to all the optics channels.  Jenne will be modifying it further so as to rename more channels.

  8261   Fri Mar 8 16:05:56 2013 yutaBureaucracyGeneralaction items for PRMI / ALS-FPMI

We should focus our work both on PRMI and ALS-FPMI (elog #8250).

CDS:

    - Check out ASS and A2L working -JENNE (ALS done, ASS on going elog #8229)
    - Are all whitening filters for PDs toggling correctly? -JENNE, JAMIE (POX11 was OK, elog #8246)

PRMI locking:
    - Adjust I/Q rotation angles for error signals -JENNE, YUTA (coarsely done elog #8212)
    - Adjust filters -JENNE, YUTA (coarsely done elog #8212)
    - Coil balancing for BS (and ITMs/ETMs) -YUTA (done elog #8182)
    - Calculate sensing matrix for PRMI and convert them into physical units -JENNE, JAMIE
    - Measure sensing matrix for PRMI -JENNE, MANASA
    - Measure 55 MHz modulation depth -KOJI

PRC characterization in PRMI:

    - Measure PR2 loss from flipping -MANASA (on going elog #8063)
    - Measure mode matching ratio -JENNE, YUTA
    - Measure finesse, PR gain -JENNE, YUTA (done elog #8212)
    - Calibrate PRM and/or ITM oplevs -MANASA, YUTA (done elog #8221)
    - Measure g-factor by tilting PRM or ITMs -JAMIE, YUTA (coarsely done elog #8235, use other methods to check)
    - Simulate intra-cavity power dependance on PRM tilt -JAMIE (see elog #8235)
    - Calculate expected finesse, PR gain -JENNE
    - Mode match and align aux laser from POY -ANNALISA (on going elog #8257)

ALS:
    - Prepare for installation of new end tables on next vent -MANASA
    - Install green DC PDs and cameras on PSL table -JENNE, MANASA
    - Make ALS handing off to DARM/CARM LSC script -JENNE, YUTA
    - Demonstrate FPMI using ALS -JENNE, YUTA
    - Phase tracker characterization -YUTA, KOJI (bad whitening elog #8214)
    - better beatbox with whitening filters -JAMIE, KOJI

Others:
    - Update optical layout CAD after PR2 flipping -MANASA
    - IMC REFL demod phase rotation -EVAN, ANNALISA (done elog #8185)
    - Look into PMC drift -JENNE, MANASA
    - Measure RFAM contribution to error signals -YUTA
    - Look into TT2 drift -JENNE, MANASA

ELOG V3.1.3-