ID |
Date |
Author |
Type |
Category |
Subject |
553
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Mon Jun 23 19:33:01 2008 |
rana, jenne | Update | IOO | MC_F Noise check |
We looked at the MC_F spectrum because Rob and Yoichi said that it had gone 'all crazy'. It
seemed fine as we looked at it (even with only one boost stage on) so we looked for things
that might be marginal and make it go nuts.
At the error point (Q mon on the demod board and TEST IN1) of the MC Servo board we saw the
old 3.7 MHz signal (comes from the 33 MHz RFAM getting demodulated by the 29.5 MHz MC LO)
and thought that this might cause some worries. So we installed Jenne's passive elliptic
low pass which has a 3.7 MHz zero.
This wiped out the 3.7 MHz noise but we were not able to re-create the extra frequency noise
so its unlikely to have fixed the main problem. However, we leave it in because its good. If
there is a need to revert it, we have left hanging on the side of the rack the old cable which
was a SMA->TNC making a direct, unfiltered connection between the MC Demod board and the MC
servo board.
More before and after results from Jenne tomorrow, but for now here is a calibrated MC_F spectrum
using the new MC_F-Reference.xml template file.
We also noticed that we could make some small effects on the MCF spec by adjusting the PMC gain so
there's probably more hay to be made there using a lead brick and a gain slider. More in Jenne's
entry. |
Attachment 1: mcf.png
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552
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Mon Jun 23 15:22:04 2008 |
rana | Bureaucracy | SAFETY | Laser Safety Walkthrough today |
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Attachment 1: Walkthrough08.jpg
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551
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Sun Jun 22 21:38:49 2008 |
rob | HowTo | General | IFO CONFIGURE |
Now that we're getting back into locking, it's nice to have a stable alignment of the interferometer.
Thus, after you're done with your experiment using subsets of the interferometer (such as a single arm),
please use the IFO_CONFIGURE screen, and click "Restore last Auto-Alignment" in the yellow "Full IFO" section.
If you don't know what this means/how to do this, you shouldn't be using the interferometer on your own. |
550
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Fri Jun 20 17:42:48 2008 |
steve | Update | PSL | SS trap scattering compared to black glass trap |
Circular SS304 trap was compared to wedged black glass trap.
The measurement set up of entry 529 was changed to define polarization.
CrystaLaser was remounted in horizontal position and half wave plate was placed after it.
These measurements were done in horizontal polarization.
atm1: the cSSt and wBGt was moved horizontally, ~90 degrees of the incident beam
atm2: traps were rotated around the incident beam, ~20 degrees each direction
atm3: set up
atm4: top view of traps
atm5: side view of trap |
Attachment 1: cSSt_1.png
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Attachment 2: cSSt_2.png
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Attachment 3: scatset_61908.png
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Attachment 4: cSSt&wBGt.png
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Attachment 5: cSStbeam.png
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549
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Fri Jun 20 08:30:27 2008 |
stiv | Update | Photos | 40m summer line up 2008 |
atm1: John, Alberto, Yoichi, Koji, Masha, and Sharon
atm2: surf students Max of CIT, Sharon of MIT, Masha of Harvard, Eric of CIT not shown |
Attachment 1: P1020559.png
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Attachment 2: P1020560.png
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548
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Fri Jun 20 02:20:33 2008 |
Yoichi | Update | | PMC transmittance degradation |
The PMC transmitted light power has been degrading constantly for last two weeks (see the attachment 1).
I went down to 2.55V.
The output of the MOPA is constant during this period. More strangely, the reflected power from the PMC is also constant.
One possible explanation is the contamination of the PMC mirrors. But I don't know why it started two weeks ago.
I tweaked the alignment of PMC and was able to recover the transmitted power to above 2.7V (attachment 2).
I will keep eye on this issue. |
Attachment 1: pmc_trans_long_trend.pdf
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Attachment 2: pmc_trans_improvement.pdf
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547
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Fri Jun 20 01:38:55 2008 |
rana | Update | PEM | 20 day Weather |
Yoichi showed me that its possible to make PNG images from PS using GS:
gs -sDEVICE=png16m -sOutputFile=foo.png bar.ps |
Attachment 1: test.png
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546
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Thu Jun 19 20:22:03 2008 |
rana | Update | General | FE Computer Status |
I called Rolf (@LLO) who called Alex (@MIT) who suggested that we power cycle every crate
with an RFM connection as we did before (twice in the past year).
Rob and I followed Yoichi around the lab as he turned off and on everything. There
was no special order; he started at the Y-end and worked his way into the corner and
finishing at the X-End. Along the way we also reset the 2 RFM switches around fb0.
This cured the EPICS problem; the FEs could now boot and received the EPICS data.
However, there are still some residual channel hopping-ish issues which Rob and Yoichi are
now working on. |
545
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Thu Jun 19 15:52:06 2008 |
Alberto | Configuration | Computers | Measure of the current absorbed by the new Megatron Computer |
Together with Rich Abbot, sam Abbot and I measured the current absorbed by the new Megatron computer that we installed yesterday in the 1Y3 rack. The computer alone absorbs 8.1A at the startup and then goes down to 5.9A at regime. The rest of the rack took 5.2A without the computer so the all rack needs 13.3 at the startup and the 11.1A.
We also measured the current for the 1Y6 rack where an other similar Sun machine has been installed as temporary frame builder and we get 6.5A.
Alberto, Rich and Sam Abbot |
544
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Wed Jun 18 18:50:09 2008 |
rana | Update | Computers | It can only be attributable to human error. (HAL - 2001) |
There has been another one of "those" events and all of the front end machines are down.
We poked around and Rob determined that the FEs can't get the EPICS data from EPICS. The
dcuepics machine is hooked up and running and all of the epics binaries are running. We also
tried resetting its RFM switch as well as power cycling the box using the "poweroff" command.
Not a sausage.
Rob points out that although the Signal Detect lights are on on the cards, the 'Own Data' light
is not on on the dcuepics' card although it is on for some of the cards on the other boxes.
We have placed messages with the Russian. If anyone sees him, don't let him go without fixing things.
Also, make sure to follow him around with notepad and possibly a camera to record what it is that
he does. If he's muttering, maybe try to use a sensitive hidden sound recorder. |
542
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Wed Jun 18 18:32:09 2008 |
Max Jones | Update | Computer Scripts / Programs | NB Update |
I am reconfiguring the the noisebudget code currently in use at the sights. To that end, I have done the following things (in addition to the elog I posted earlier)
In get_dtt_dataset.m - I added C1 specific cases for DARM_CTRL, SEIS, and ITMTRX changing the specific channels to make those in use at caltech
In LocalizeSite.m - I changed the NDS_PATH to match caltechs. I left NDS_HOST untouched.
Since I am trying to get SEIS and DARM to work initially I added C1 specific cases to both of these.
Better documentation may be found in /users/mjones/DailyProgressReport/06_18_08. Suggestions are appreciated. Max. |
541
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Wed Jun 18 18:26:19 2008 |
Yoichi | Update | PSL | Finding the optimal operation temperature for the NPRO by the slow act scan |
Being suspicious of the temperature stabilization of the NPRO crystal, I ran the slow scan script written by Rana to find the suitable operation temperature.
The procedure is the same as the one explained in the entry below:
http://www.ldas-sw.ligo.caltech.edu/ilog/pub/ilog.cgi?group=40m&task=view&date_to_view=09/04/2006&anchor_to_scroll_to=2006:09:04:22:23:56-rana
The attached plots show the results. By looking at C1:PSL-126MOPA_126MON, I set the slow slider voltage to 0.
This time, it looks like the temperature control of the NPRO crystal is working fine.
Obviously, PMC picks up many higher order modes. I will try to mode match/align the PMC later. |
Attachment 1: FSS-slow-scan.pdf
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540
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Wed Jun 18 18:20:10 2008 |
Yoichi | Update | PSL | Investigation on the NPRO temperature stabilization glitches |
As Rob pointed out in http://dziban.ligo.caltech.edu:40/40m/537 the MOPA NPRO has been showing some glitchiness in the LTEC loop.
Following Rana's suggestion, Steve and I opened the MOPA and directed a heat gun for a minute to the NPRO hoping that we can see something in the LTEC loop.
The first attachment shows the behavior of LTMP and LTECH along with DTMP and DTECH at the time of the heat gun attack.
T=0 is the time when Steve directed the heat gun to the NPRO. There is no response neither in LTMP nor LTECH.
DTMP and DTECH look like responding.
Around the center, there is a dip in LTMP. This might be caused by removing the heat gun. But we are not sure. This kind of small glitches can be found in LTMP everywhere (see the attachment 2).
It looks like the LTMP sensor is not working, or the LTECH loop is actually working but the LTECH reading is broken.
However, the scan of the slow actuator (temperature) shows the LTECH loop is actually working. So it is a bit confusing.
More investigation is necessary.
See the next entry by me.
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Attachment 1: LTEC-loop-HeatGun-Response.pdf
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Attachment 2: LTMP-glitches.pdf
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539
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Wed Jun 18 16:37:54 2008 |
steve,rana | Update | SAFETY | CO2 test in the east arm |
The CO2 laser and table are in the east arm for characterization of the mechanics. We
will not be operating it until we have an SOP (which is being written). No worries. |
Attachment 1: co2.png
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538
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Wed Jun 18 16:07:57 2008 |
rob | Summary | Computers | RFM network down |
The RFM network tripped off around noon today. It's still down. The problem appears to be with the EPICS interface (c1dcuepics). Trying to restart one of the end stations yields the error: No response from EPICS.
Possible causes include (but not limited to): busted RFM card on c1dcuepics, busted PMC bus on c1dcuepics, busted fiber from c1dcuepics to the RFM switch. We need Alex. |
537
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Wed Jun 18 00:19:29 2008 |
rob | Update | PSL | MOPA trend |
15 day trend of MOPA channels. The NPRO temperature fluctations are real, and causing the PMC to consistently run up against its rails. The cause of the temperature fluctations is unknown. This, combined with the MZ glitches and Miller kicking off DC power supplies is making locking rather tetchy tonight. Hopefully Yoichi will find the problem with the laser and fix it by tomorrow night. |
Attachment 1: MOPAtrend.png
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536
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Tue Jun 17 22:00:53 2008 |
John | HowTo | PSL | Problems turning MZ servo on/off |
We were unable to toggle the MZ servo on/off (Blank/Normal) from MEDM. Pushing on the Xycom board and cables changed the fault from constant to intermittent. At least one lock loss has been caused by a MZ glitch. |
535
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Mon Jun 16 18:26:01 2008 |
Max Jones | Update | Computer Scripts / Programs | Noise Budget Changes |
In the directory cvs/cds/caltech/NB the following changes were made:
I created temporary files in ReferenceData for the C1 by copying and renaming the corresponding H1 files.
- C1_SRD_Disp.txt
- C1IFOparams.m
- C1_NoiseParams.m
In getmultichan.m I added a C1 case.
In NoiseBudget.m I added a C1 case with modified sources array to include only DARM and Seismic
I appreciate and suggestions. Max.
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534
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Fri Jun 13 11:17:25 2008 |
Yoichi | Update | PSL | PMC transmittance at high power |
We received a new cable for the Scientech calorimeter. So I measured the transmittance of the PMC at higher power.
Summary:
Input power = 2.298W
Output power = 1.364W
Transmittance = 59%
Detail:
The input power to the PMC was measured between the two mode matching lenses by the calorimeter.
2.298W looks a bit too low. Actually, the calibrated monitor PD on the MEDM screen shows about 3W output from MOPA.
So we (me and Steve) measured the power right after the PBS after the periscope from MOPA with the HWP set to maximize the transmission of the PBS.
It was 2.77W. According to Steve's previous measurement, the first mirror of the periscope transmits about 200mW of the incoming light to the monitor PD. So the actual output of the MOPA is about 2.97W, which is consistent with the monitor PD reading.
The aperture of the EOM for the PMC control is glowing a lot. We suspect this is the main cause of the loss (from 2.77W to 2.298W).
We may want to re-align the EOM.
The output light from the PMC was picked off by a glass slide. The reflectance of the glass slide was measured first at a lower power (input 98mW, reflected power 1.58mW). Assuming that the reflectance is the same for the higher power, I turned up the input power to the PMC. This time, the picked off power was 22.45mW. This means the actual output power is 98/1.58*22.45=1364mW. The glass slide was kept at the same angle through out the measurement.
The measurement of the output power was done by the Ophir power meter. So calibration difference between the Ophir and the calorimeter may introduce some error. |
533
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Thu Jun 12 15:55:15 2008 |
rob | Update | Locking | report |
Quote: | Rob: Awesome figure. As you can imagine, I have lots of questions, and hope that you will consider this figure to be the beginning, leading to ever-more detailed versions. But for now, I just want to ask whether you understand *what* is twitchy, and what the twitchiness does to prevent you from taking this further? |
I definitely don't understand what's twitchy, but I have suspicions. Tonight we'll try to start by revisiting the other loops (the non-CARM loops) and see how they're dealing with the changing power levels. It may be that the DARM loop is going unstable due to gain variations (due to either increasing power or to rotation of demod phase) or it could be the PODD (or SPOB) saturating with increased power in the recycling cavity. I just hope the glitchiness doesn't have a digital origin. |
532
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Thu Jun 12 15:09:33 2008 |
alan | Update | Locking | report |
Rob: Awesome figure. As you can imagine, I have lots of questions, and hope that you will consider this figure to be the beginning, leading to ever-more detailed versions. But for now, I just want to ask whether you understand *what* is twitchy, and what the twitchiness does to prevent you from taking this further? |
531
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Thu Jun 12 01:51:23 2008 |
rob | Update | Locking | report |
rob, john
We've been working (nights) on getting the IFO locked this week. There's been fairly steady incremental progress each night, and tonight we managed to control CARM(MCL) using PO-DC, with the CARM(AO) path also on PO-DC. In the past, reaching this state has usually meant we're home free, as we could just crank the gain on the common mode servo and merrily reduce the CARM offset. Tonight, however, this state has been very twitchy, and efforts to ramp up the gain have been unsuccessful.
I've attached a diagram which I hope makes clear where we are in the stages of lock acquisition. |
Attachment 1: lock_control_sequence.png
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530
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Wed Jun 11 15:30:55 2008 |
josephb | Configuration | Cameras | GC1280 |
The trial use GC1280 has arrived. This is a higher resolution CMOS camera (similar to the GC750). Other than higher resolution, it has a piece of glass covering and protecting the sensor as opposed to a plastic piece as used in the GC750. This may explain the reduced sensitivity to 1064nm light that the camera seems to exhibit. For example, the image averages presented here required a 60,000 microsecond exposure time, compared to 1000-3000 microseconds for similar images from the GC750. This is an inexact comparison, and the actual sensitivity difference will be determined once we have identical beams on both cameras.
The attached pdfs (same image, different angles of view) are from 200 averaged images looking at 1064nm laser light scattering from a piece of paper. The important thing to note is there doesn't seem to be any definite structure, as was seen in the GC750 scatter images.
One possibility is that too much power is reaching the CMOS detector, penetrating, and then reflecting back to the back side of the detector. Lower power and higher exposure times may avoid this problem, and the glass of the GC1280 is simply cutting down on the amount passing through.
This theory will be tested either this evening or tomorrow morning, by reducing the power on the GC750 to the point at which it needs to be exposed for 60,000 microseconds to get a decent image.
The other possibility is that the GC750 was damaged at some point by too much incident power, although its unclear what kind of failure mode would generate the images we have seen recently from the GC750. |
Attachment 1: GC1280_60000E_scatter_2d.pdf
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Attachment 2: GC1280_60000E_scatter_3d.pdf
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529
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Wed Jun 11 11:45:25 2008 |
steve | Update | PSL | ss trap works |
The trap works well at 3 W level. No back reflected beam coming out of the trap on low power
sensing card level. The back scattering was not measured. The trap is insensitive to small pointing variations.
The SS surface did not show any visible degradation after 16 hrs of 3w exposure at elliptical beam size 4x8 mm
It is ready to be placed into the 35 W beam. |
Attachment 1: P1020534.png
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Attachment 2: P1020533.png
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528
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Tue Jun 10 08:37:18 2008 |
steve | Update | PSL | beam trap is being tested |
High power beam trap is being tested just west of FSS area on psl enclosure.
When the pmc is operating at low power that means that the rest of the 3W is going into the
circular SS trap.
Please beware of the high power beam trap test |
Attachment 1: trapss3w.png
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527
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Mon Jun 9 17:57:59 2008 |
Yoichi | Configuration | PSL | PMC input power backed to the original |
I rotated back the HWP before the PBS to restore the input laser power to the PMC.
Now the reading of PSL-PMC_PMCTRANSPD is 2.7. |
526
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Mon Jun 9 17:32:14 2008 |
Yoichi | Configuration | PSL | PMC transmittance |
I checked the current PMC transmissivity at a low power.
The input laser power to the PMC was reduced to 75mW by rotating the HWP in front of the PBS.
In this configuration, the output power from the PMC was 50mW. So the transmittance is about 66%.
The reading of C1:PSL-PMC_PMCTRANSPD is now 0.1 whereas it was 2.7 before turning the power down.
I will check the transmittance at a higher power when I get the cable for the 35W calorie meter, which is missing now. |
525
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Fri Jun 6 16:47:04 2008 |
josephb | Configuration | Cameras | GC650 scatter images of 1064nm light |
Took images similar to the scattered light images from earlier, except with the CCD GC650 camera. The first three attached plots are an average of all 200 images, an average of the first 100 and then an average of the last 100 images.
They show no definite structure. The big red blob which changes with time may be a brighter reflection, although it virtually the same type of setup as the GC750 images.
To do this properly, I should grab a short focal length lens and simply blow up the beam to a size greater than the detector area and simply fix both cameras looking into.
The last set of plots are mean and standard deviation plots from a previous set of runs on 5/29/08 with the GC750 and GC650 running at the same time. The GC650 was receiving approximately 33% of the total power and GC750 was receiving 66% (in otherwords a factor of 2 more). |
Attachment 1: GC650_scatter_200.pdf
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Attachment 2: GC650_scatter_100a.pdf
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Attachment 3: GC650_scatter_100b.pdf
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524
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Fri Jun 6 16:10:51 2008 |
steve | Update | PSL | HEPA filters are running at 100% |
The psl HEPA filters were turned up to run at 100% to accommodate beam trap work on Tuesday, June 3, 2008 |
523
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Fri Jun 6 15:56:00 2008 |
steve | Bureaucracy | SAFETY | Yoichi received safety training |
Yoichi Aso received 40m specific safety training. |
522
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Fri Jun 6 11:19:13 2008 |
Caryn | Summary | PEM | Filtering MC_L and MC_F with PEM:ACC and microphone |
Tried to filter MC_L and MC_F with acc/seis data and microphone data using wiener filter (levinson)
-Used get_mic_data.m and miso_filter_lev.m to make SISO filter for 2 minutes of IOO-MC_F data. Used PEM-AS_MIC signal as noise input data. Filters calculated at initial time were applied to later data in 1 hour intervals.
-microphone filter did not seem to filter MC_F very well in high frequency range using this filtering procedure.
-residual is larger than est (see MC_F pdf)
-Used do_all_time_lev.m to make graph of max(rms(residual)) to N(order) for different times.(note for each N, filter was calculated for initial time and then applied to data at other times).
-relation of max(rms(residual)) to N(order) is time sensitive (note-on graph, time interval is 1hour) (see MC_F pdf)
-Presumably, max(rms(residual)) should decrease as N increases and increase as time increases since the filter probably becomes worse with time. I think the reason this isn't always true in this case is that the max(rms(residual)) corresponds to a peak (possibly a 60Hz multiple) and the wiener filter isn't filtering out that peak very well.
-Used get_z_data.m and miso_filter_lev.m to make MISO filter for 2 minutes of IOO-MC_L used the following signals as noise input data
PEM-ACC_MC1_X
PEM-ACC_MC2_X
PEM-ACC_MC1_Y
PEM-ACC_MC2_Y
PEM-ACC_MC1_Z
PEM-ACC_MC2_Z
PEM-SEIS_MC1_Y
-Filter was applied to later data in 2hour intervals.
-Used do_all_time_lev.m to make graph of max(rms(residual)) to N(order) for different times.(note for each N, filter was calculated for initial time and then applied to data at other times).
-acc/seis filter seemed to filter MC_L OK for 128,256,512Hz srates. 64 Hz wasn't ok for certain N's after a period of time.
-residual is smaller than est for srates not 64Hz (see MC_L pdf)
-residual is larger than est for 64Hz at N=1448 for later times (see MC_L pdf)
-relation of max(rms(residual)) to N is not as time sensitive for higher sample rates (note-on graph, time interval is 2hours) (see MC_L pdf). Perhaps the levinson 64Hz sample rate filter doesn't do as well as time passes for these signals. When the filter didn't do well, the max(rms(residual)) seemed to increase with N.
-For 512Hz sample rate filter the max(rms(residual)) decreased with time. If the max(rms(residual)) were an indication of filter performance, it would mean that the 512Hz filter calculated at the initial time was performing better later as hours passed by! Perhaps max(rms(residual)) isn't always great at indicating filter performance.
Programming notes
-I had to modify values in do_all_time_lev.m to get the program to loop over the srates,N's,times I wanted
-do_all_time_lev.m is not as clean as do_all_lev.m
-for making the plots do_all_lev.m (which isn't really a procedure and is messy) has some examples of how to plot things from do_all_time_lev.m. |
Attachment 1: MC_F.pdf
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Attachment 2: MC_L.pdf
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Attachment 3: miso_filter_lev.m
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function [s] = miso_filter_lev(N,srate,rat,z)
%MISO_FILTER_LEV(N,srate,z) uses miso_firlev to get levinson
% FIR Wiener filter of order N-1, using impulse response of
% N/srate. z is a structure gotten from the get_data function.
% z(end) is the signal which is filtered using z(i) for all i.
% 'rat' is the fraction of z which will be put into filter
% funtion. The data from z is downsampled using srate and
% detrended. Let rat=1. I don't have that part working yet.
... 107 more lines ...
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Attachment 4: get_mic_data.m
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function[z,t0,duration]=get_mic_data(t,d_t,d)
%get_mic_data gets data for'C1:IOO-MC_F', 'C1:PEM-AS_MIC,
% Example: z = get_mic_data('now',120,60)
% start time is 't- d_t' so d_t should be given in seconds. t should be given
% as a number like 893714452. d is duration in seconds. get_mic_data saves
% data to a file in current directory named 'temp_mic'. You will be asked to
% save file as 'mic_(start_time)_(duration)'.
duration = d;
... 32 more lines ...
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Attachment 5: do_all_time_lev.m
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function[r] = do_all_time_lev(n,t0,int,duration,N,srate,rat,order,time,MC_L,MC_F,sample_rate)
%do_all_time explores how filter performance changes with time, sample rate,
%and order of filter. Outputs data,noise estimate, structure of max
%rms error and other info. It uses get_data, miso_filter_lev, and miso_filter_int and retrives
%MC_Ldata or MC_Fdata for multiple times, calculates a miso_filter for initial-time data
%file, applies filter to the other data files, and keeps track of the...
%max(rms(residual)) for each filter. n+1 is number of data files. int is time interval between
%data files, t0 is start time, duration is duration of each data file, srate
%is the sample rate for which filter is calculated, n_N is number of orders
%of the filter you want the program to calculate,int_N is interval by which N
... 215 more lines ...
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Attachment 6: do_all_lev.m
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function[r] = do_all_lev(n,t0,int,duration,n_N,int_N,n_srate,int_srate,rat,MC_L,MC_F)
%do_all_lev explores how filter performance changes with time, sample rate,
%and order of filter. Outputs data,noise estimate, structure of max
%rms error and other info. It uses get_data, miso_filter_lev, and miso_filter_int and retrives
%MC_Ldata or MC_Fdata for multiple times, calculates a miso_filter for initial-time data
%file, applies filter to the other data files, and graphs the rms of the cost
%function vs time. n+1 is number of data files. int is time interval between
%data files, t0 is start time, duration is duration of each data file, srate
%is the sample rate for which filter is calculated, n_N is number of orders
%of the filter you want the program to calculate,int_N is interval by which N
... 283 more lines ...
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Attachment 7: do_all_plot.m
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function[r] = do_all_plot(r,x,v)
%do_all_plot plots variables contained in r(structure from
%do_all_time_lev).Plots error(r.B.y) vs x. x can be
%'s'(srate),'N'(order),'t'(time),'p'(impulse response). v can be 's','N','t'.
%example: do_all_plot(r,'s','t') makes a plot of error vs srate for
%different times.
kk=1
err_N_srate=0
... 388 more lines ...
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Attachment 8: miso_filter_int.m
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function [s] = miso_filter_int(s,y)
%miso_filter_int inputs a filter and a structure array of data sets y, applies filter to data, and
%outputs a structure with fields: ppos(signal frequ spectrum),perr(cost
%function frequ spectrum),pest(signal estimate frequency
%spectrum),f(frequency),target(signal),est_darm(noise estimate),t(time).
%data file for which filter has been calculated is s (obtained using miso_filter).
%y consists of data structures which will be filtered using
%filter from s. Then the power spectrum of the difference between signal and filtered-data is
%graphed for all the data files of y for comparison too see how well filter performs
%over time. Note if you want to create a y, take z1,z2,z3,etc. structures
... 120 more lines ...
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521
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Thu Jun 5 13:35:23 2008 |
josephb | Configuration | Cameras | GC750 looking at 1064nm scattered light |
I've taken 200 images of the GC750 (CMOS) camera while holding it by hand up to a beam card (also held by hand) in the path of ~5mW of beam power. I then averaged the images to produce the fourth attached plot.
Rob has pointed out the image looks a lot like PCB traces. So perhaps we're seeing the electronics behind the CMOS sensor?
I repeated the same experiment with HeNe laser light (again scattered off a card). These show none of the detailed structure (just what looks to be a large reflection from the card moving around depending on how steady my hand was). These are the first 3 attached plots. So only 1064nm light so far sees these features.
As a possible solution, I did a quick and dirty calibration by dividing a previous PSL output beam by the 1064 average scatter light values. These produce the last attached pdf (with multiple images). The original uncalibrated image is on top, while the very simply calibrated image is on the bottom of each plot.
It seems as the effect may be power dependent (which could still be calibrated properly, but would take a bit more effort than simply dividing), as determined by looking at the edges of the calibrated plot. |
Attachment 1: GC750_HeNe_scatter_avg.pdf
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Attachment 2: GC750_HeNe_scatter_avg2.pdf
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Attachment 3: GC750_HeNe_scatter_avg3.pdf
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Attachment 4: GC750_scatter_avg.pdf
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Attachment 5: GC750_nitrogen_white.pdf
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Thu Jun 5 10:46:26 2008 |
josephb | Configuration | Cameras | Approximately uniform reflected white light |
In an attempt to investigate the structures seen in previous images for the GC750, I aimed it at a relatively clean section of gray table top roughly a cm or two from the surface and took images (without a lens). As I was holding this with my hand, the angle wasn't completely even with the table, and thus there's a gradient of light in the pictures. However, one should in principle be able to pick out features (such as a circular spot with less sensitivity), but these do not show up.
In my mind, these images seem to indicate the electronics are fine, and suggest that the CMOS or CCD detectors themselves are undamaged (at least in regards to white light, as opposed to 1064nm). An issue with the plastic cap (protective piece) may be the culprit, or perhaps a tiny bit of dust, which the incoherent light from all angles goes around efficiently?
Will try blowing the cameras with clean nitrogen today and see if that removes or changes the circular structure we have seen. |
Attachment 1: GC650_white_light.pdf
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Attachment 2: GC750_white_light.pdf
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519
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Wed Jun 4 16:57:12 2008 |
josephb | Configuration | Cameras | Dark images from cameras (electronics noise measurement) |
The attached pdfs are 1 second and 1 millisecond long integrations from the GC650 and GC750 cameras with a cap in place - i.e. no light.
They include the mean and standard deviation values.
The single bright pixel in the 1 second long exposure image for the GC650 seems to be a real effect. Multiple images taken show the same bright pixel (although with slightly varying amplitudes).
The last pdf is a zoom in on the z-axis of the first pdf (i.e. GC650 /w 1 sec exposure time).
I'm not really sure what to make of the mean remaining virtually fixed for the different integration times for both cameras. I guess 0 is simply offset, but doesn't result in any runaway integrations in general. Although there are certainly some stronger pixels in the long exposures when compared to the short exposures.
Its interesting to note the standard deviation actually drops from the long exposure to the short exposure, possibly influenced by certain pixels which seem to grow with time.
The one with the least variation from its "zero" was the 1 millisecond GC750 dark image. |
Attachment 1: GC650_1sec_dark.pdf
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Attachment 2: GC650_1msec_dark.pdf
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Attachment 3: GC750_1sec_dark.pdf
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Attachment 4: GC750_1msec_dark.pdf
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Attachment 5: GC650_1sec_dark_zoom.pdf
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Wed Jun 4 16:25:06 2008 |
Caryn | Summary | PEM | microphone moved |
The microphone 'C1:PEM-AS_MIC' has been moved right a bit. This change didn't seem to have much effect on filtering the 'C1:IOO-MC_L' signal, at least not compared to how the filter changes with time. Also used microphone data to filter MC_L data using firwiener filter/levinson. The N(order) and sample rate were varied to see how the filter changed. Attached are graphs of the max(rms(noise_estimate)) vs N or IR for varying srate. Note that filtered_signal=signal-noise_estimate. So, the larger the noise_estimate, the more the filter subtracts from the signal.
Green-filtered signal
blue-noise estimate
red-MC_L signal
note decreasing sample rate is more effective than increasing N (higher N takes more time to compute)
note sample rate doesn't change the max(rms(noise_estimate)) very much if impulse response time remains constant
note the 64hz, N=7000 (impulse response about 110s) filter is a better filter than the 512Hz, N=7000(impulse response about 14s) |
Attachment 1: 1_MC_L.pdf
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Wed Jun 4 13:46:42 2008 |
josephb | Configuration | Cameras | Changing incident angle images |
Attached are images from the GC650 and GC750 when the incident angle was varied from 0 tilt (normal incidence) to 5,10, and 20 degrees. Each time the beam was realigned via the last turning mirror to be on roughly the same spot. This light was a pickoff of the PSL table light just before it leaves the table.
Images include the raw data, fit to the data, residual normalized by peak power "w(1)", and normalized by the individual bin power.
The first pdf includes 0 degrees (normal) and ~5 degrees of tilt for the GC650 (CCD) camera.
The second pdf includes ~10 and ~20 degrees of tilt images for the GC650 (CCD) camera.
The third pdf includes 0 and ~5 degrees of tilt for the GC750 (CMOS) camera.
The fourth pdf includes ~10 and ~20 degrees of tilt for the GC750 (CMOS) camera.
Things to note:
1) GC750 camera seems to have a structure on the camera itself, somewhat circular in nature. One possible explanation is the camera was damage at a previous juncture due to too much light. Need to check earlier images for this problem.
2) GC650 has "bands" which change direction and thickness with angle. Also at higher incidence angle, the sensitivity seems to drop (unlike the GC750 where overall power level seems to stay constant with increasing angle of incidence).
3) GC650 seems to have a higher noise floor,seen from the last plot of each pdf (where each pixel of the residual is normalized by the power in the corresponding pixel of the fit). |
Attachment 1: GC650_0dg_5dg.pdf
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Attachment 2: GC650_10dg_20dg.pdf
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Attachment 3: GC750_0dg_5dg.pdf
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Attachment 4: GC750_10dg_20dg.pdf
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Wed Jun 4 10:18:52 2008 |
steve | Update | PSL | wedged SS beam trap |
I moved the SS trap over to the psl table.
Texas super # 8 was used from the large shipment.
TXs#8 scattering measured as before, meaning the polishing is good.
Go's squeezing power pick up 350 mW was used.
I made two ~30 degrees wedge traps using 6" x 4" and 12" x 4" SS 0.039" thick
with copper backing of similar size.
There was too much scattering and I could not minimize them all.
It is very helpful to have so much space on the psl table.
It shows more of the weakness of this kind of trap.
I did not dare to turn up the power. |
Attachment 1: trap1.png
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Attachment 2: trap2.png
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Tue Jun 3 12:33:36 2008 |
Andrey | Update | Cameras | Andrey, Josephb |
Continuing our work with cameras,
1) we removed both cameras from their places on Monday afternoon, and were taking the beam-scans with a special equipment (see elog-entry 511) from Bridge bld.,
2) and on Tuesday morning we putted back the GC-750 camera into the transmitted beam path, camera GC-650 into the reflected beam path. We plan to compare the images from the "reflection camera" for several different angles of tilt of the camera. |
514
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Tue Jun 3 10:40:27 2008 |
tobin | Configuration | Computers | new dataviewer |
Alex let me know the secret location of the latest dataviewer executable for Linux. It is:
http://www.ligo.caltech.edu/~aivanov/upload/dv/Control/dc3
If your linux dataviewer on linux2 has the "year field not filled in" bug, you should download this into /usr/local/bin/dc3 (after making a backup of that file).
It looks like there's no dataviewer installed on rosalba yet. We should figure out a better directory layout for the linux machines; currently dataviewer is installed locally on linux2. It should be in /cvs/cds/caltech/apps/linux/something so that all the linux machines see the same installation. |
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Tue Jun 3 10:19:45 2008 |
tobin | Configuration | Computers | big machine |
Several of us transported the big new awesome Sun box from Bridge over to
the 40m last week. If I recall correctly, it's a SunFire X4600 with
something like sixteen 64-bit AMD processor cores at 2.8 GHz. It sounds
like a jet engine when it starts up (before the cooling fans are throttled
back) and has four power supplies (each with its own connection
to the wall). It has slick removable hard disks and fan units too. Our
working name for it is "megatron".
Anyway. It came with two hard disks, one with Solaris 10 installed. I took
the other hard disk over to Alex, who copied a Realtime Linux installation
onto it. Alex says it boots and runs fine.
It remains for you guys to install the machine onto rails and install the
whole thing into a rack. Before it goes into service as a realtime control
machine, you might as well install Matlab on it and do some heavy-duty
computation.
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512
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Tue Jun 3 02:15:29 2008 |
Andrey | Summary | Cameras | Fitting results |
There have been a lot of work going on related to the processing of images captured by the cameras GC-650 and GC-750 recently.
In the end of the week of May 30 Joseph and me (Andrey) installed the two cameras capturing the images of the pick-off of the main beam on the PSL optical table. The cameras are located after the picked-off beam going towards the "PSL position QPD", after the 33-66 beamsplitter (33% of reflection and 66% of transmission).
Initially (on May 30) the GC-650 camera was taking the images of reflected beam, while the camera GC-750 was taking images of transmitted beam. On Monday June 2 we switched the positions of the cameras, so GC-650 appeared to be on the path of the transmitted beam and GC-750 on the path of the reflected beam.
I (Andrey Rodionov) was able in the weekend to succeed in writing a Matlab program that performs the two-dimensional Gaussian fitting of the captured images, and I used that program to fit the images from the cameras.
The program fits the camera data by a two-dimensional Gaussian surface:
Z = A * exp[ - 2 * (X - X_Shift)^2 / (Waist_X)^2 ] * exp[ - 2 * (Y - Y_Shift)^2 / (Waist_Y)^2 ] + CONST_Shift,
where A, X_Shift, Waist_X, Y_Shift, Waist_Y, CONST_Shift are 6 parameters of the fit.
Attached are the pdf-files showing the results: images taken with our cameras, the 2-dimensional Gaussian fit for these images and the surfaces of residuals. Residuals are differences between the exact beam profile and the result of fitting. In normalized version of residual graph I normalize it by the first coefficient of fitting A, the factor in front of the exponents. |
Attachment 1: May30-GC650.pdf
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Attachment 2: May30-GC750.pdf
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Attachment 3: June02-GC650.pdf
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Attachment 4: June02-GC750.pdf
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511
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Mon Jun 2 12:20:35 2008 |
josephb | Bureaucracy | Cameras | Beam scan has moved |
The beamscan has been moved from the Rana lab back over to the 40m, to be used to calibrate the Prosilica cameras. |
510
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Sun Jun 1 19:39:35 2008 |
tobin | Configuration | Computers | elog, etc |
Phil Ehrens gave me a DVD of the 40m elog, apache, and (Jamie's) SVN archive.
I copied it to nodus:/home/controls/dvd-from-ehrens. Once we get the elog
running on nodus, we can copy the datafile over again from dziban (so that
we don't lose any elog entries) and switch over. |
509
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Sun Jun 1 19:25:10 2008 |
rana | Configuration | Computers | new monitor on op440m |
I installed the new 24" flat screen on op440m. I increased the screen resolution from 1280x1024 to 1900x1200 using
the obscure 'fbconfig' command. You can type Google it if you want.
The old monitor is on the surplus cart. If you are reading this and think you might walk from the 40 over to
Bridge, please wheel the cart full of old computer equipment (on the north side of the control room) over to Larry.
I also copied over all the images on the D40 to a folder on Kirk's computer and deleted the originals.
Dan Busby also visited us last week to help us move the drill press from the Y arm down into the sub basement
of W Bridge. |
Attachment 1: Andrey-440.jpg
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Attachment 2: Busby08.jpg
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Fri May 30 21:30:15 2008 |
tobin | Configuration | Computers | svn on solaris |
I installed svn on op440m. This involved installing the following packages from sunfreeware:
apache-2.2.6-sol9-sparc-local libiconv-1.11-sol9-sparc-local subversion-1.4.5-sol9-sparc-local
db-4.2.52.NC-sol9-sparc-local libxml2-2.6.31-sol9-sparc-local swig-1.3.29-sol9-sparc-local
expat-2.0.1-sol9-sparc-local neon-0.25.5-sol9-sparc-local zlib-1.2.3-sol9-sparc-local
gdbm-1.8.3-sol9-sparc-local openssl-0.9.8g-sol9-sparc-local
The packages are located in /cvs/cds/caltech/apps/solaris/packages. The command line to install
a package is "pkgadd -d " followed by the package name. This can be repeated on nodus to get
svn over there. (Kind of egregious to require an apache installation for the svn _client_, I
know.) |
507
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Fri May 30 12:37:45 2008 |
rob | Update | SUS | etmy oplev is back |
Quote: | I relayed the optics for ETMY-oplev as shown in pictures below.
The reflected beam goes directly to the qpd |
I turned on the servo. UGFs in PIT and YAW are ~3Hz. I had to flip the sign of the YAW. |
506
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Fri May 30 12:03:08 2008 |
josephb, Andrey | Configuration | Cameras | Head to head comparison of cameras |
Andrey and myself - Joseph B. - have examined the output of the GC650 (CCD) and GC750 (CMOS) prosilica cameras. We did several live motion tests (i.e. rotate the turning mirror, move and rotate the camera, etc) and also used a microscope slide to try to eliminate back reflections and interference.
Both the GC650 and GC750 produce dark lines in the images, some of which look parallel, while others are in much stranger shapes, such as circles and arcs.
Moving the GC750 camera physically, we have the spot moving around, with the dark lines appearing to be fixed to the camera itself, and remain in the same location on the detector. I.e. coming back to the same spot keeps showing a circle. In reasonably well behaved sections, these lines are about 10% dips in power, and could in principle be subtracted out. Its possible that the camera was damaged with too much light incident in the past, although going back to the pmc_trans images that were taken, similar lines are still visible.
Moving the GC650 camera physically seems to change the position of the lines (if one also rotates the turning mirror to get to the same spot on the CCD). It seems as if a slight change in angle has a large effect on these dark bands, which can either be thin, or very large, bordering on the size of the spot size. My guess is (as the vendor suggested) the light is interacting with the electronics behind the surface layer rather than a surface defect producing these lines. Using a microscope slide in between the turning mirror and the GC650, we were able to produce new fringes, but didn't affect the underlying ones.
Placing a microscope slide in between the last turning mirror and the GC750 does not affect the dark lines (although it does seem to add some), nor does turning the final turning mirror, so it seems unlikely to be caused by back reflection in this case.
So it seems the CMOS may be more consistent, although we need to determine if the current line problems are due to exposure to too much light at some point in the past (i.e. I broke it) or they come that way from the factory.
Attached are the results of image-processing of the images from the two our cameras using Andrey's new Matlab script. |
Attachment 1: Waveform_Reconstruction_May30-2008.pdf
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505
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Thu May 29 16:49:49 2008 |
steve | Bureaucracy | Photos | Yoichi has arrived |
Yoichi had his first 40m meeting. We welcomed him and Tobin, who is visiting, by sugar napoleons that
Bob made. |
Attachment 1: yoichi.png
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Attachment 2: bobsn.png
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Thu May 29 16:32:09 2008 |
steve | Update | SUS | etmy oplev is back |
I relayed the optics for ETMY-oplev as shown in pictures below.
The reflected beam goes directly to the qpd |
Attachment 1: P1020417.png
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Attachment 2: P1020420.png
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Thu May 29 15:58:44 2008 |
John | Summary | IOO | MC realignment |
I repeatedly adjusted the yaw of the upper mirror on the input periscope and re aligned the MC. With the PRM aligned I tried to optimise MC transmission and DC refl simultaneously. I subsequently centred the beams on WFS1/2. Attached is a 30 day trend of MC alignment and transmission. |