 Sun Nov 4 23:22:50 2007, waldman, Update, OMC, OMC PZT and driver response functions 7x
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I wrote a big long elog and then my browser hung up, so you get a less detailed entry. I used Pinkesh's calibration of the PZT (0.9 V/nm) to calibrate
the PDH error signal, then took the following data on the PZT and PZT driver response functions.:
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Sun Nov 4 23:55:24 2007, rana, Update, IOO, Friday's In-Vac work
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On Friday morning when closing up we noticed that we could not get the MC to flash any modes.
We tracked this down to a misalignment of MC3. Rob went in and noticed that the stops were
still touching. Even after backing those off the beam from MC3 was hitting the east edge of
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 Mon Nov 5 07:29:35 2007, rana, Update, IOO, Friday's In-Vac work
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Liyuan recently did some of his pencil beam scatterometer measurements measuring not the
[URL=http://en.wikipedia.org/wiki/Bidirectional_reflectance_distribution_function]BRDF[/URL] but instead the total integrated power radiated from each
surface point
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Mon Nov 5 14:44:39 2007, waldman, Update, OMC, PZT response functions and De-whitening
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The PZT has two control paths: a DC coupled path with gain of 20, range of 0 to 300 V, and a pair of 1:10 whitening filters, and an AC path capacitively
coupled to the PZT via a 0.1 uF cap through a 2nd order, 2 kHz high pass filter. There are two monitors for the PZT, a DC monitor which sniffs the
DC directly with a gain of 0.02 and one which sniffs the dither input with a gain of 10.
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Tue Nov 6 14:51:03 2007, tobin, rob, Update, IOO, Mode cleaner length
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Using the Ward-Fricke variant* of the [url=http://ilog.ligo-wa.caltech.edu/ilog/pub/ilog.cgi?group=detector&date_to_view=02/14/2004&anchor_to_scroll_to=2004:02:15:00:06:50-daniel]Sigg-Frolov
method[/url], we found the length of the mode cleaner to be [b]27.0934020183 meters[/b], a difference of [b]-2.7mm[/b] from [url=http://www.ldas-sw.ligo.caltech.edu/ilog/pub/ilog.cgi?group=40m&date_to_view=08/28/2007&anchor_to_scroll_to=2007:08:29:18:40:12-kawabe]Andrey,
Keita, and Rana's measurement on August 30th[/url].
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Tue Nov 6 15:36:03 2007, rob, Update, LSC, XARM locked
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Easily, after resetting the PSL Uniblitz shutters. There's no entry from David or Andrey about the recovery from last week's power outage, in which they
could have indicated where the procedure was lacking/obscure. Tsk, tsk. |
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Wed Nov 7 09:38:01 2007, steve, Update, VAC, rga scan
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| pd65-m-d2 at cc1 6e-6 torr |
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Wed Nov 7 16:07:03 2007, steve, Update, PSL, PSL & IOO trend
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| 1.5 days of happy psl-ioo with litle bumps in C1:PSL-126MOPA_HTEMP |
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Thu Nov 8 00:55:44 2007, pkp, Update, OMC, Suspension tests 9x
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[Sam , Pinkesh]
We tried to measure the transfer functions of the 6 degrees of freedom in the OMS SUS. To our chagrin, we found that it was very hard to get the OSEMs |
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Thu Nov 8 11:40:21 2007, steve, Update, PEM, particle counts are up
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I turned up the psl HEPA filter to 100%
This 4 days plot shows why |
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Fri Nov 9 00:23:12 2007, pkp, Update, OMC, X and Z resonances
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I got a couple of resonance plots going for now. I am still having trouble getting the Y measurement going for some reason. I will investigate that tommorow.
But for tonight and tommorow morning, here is some food for thought. I have attached the X and Z transfer functions below. I compared them to Norna's plots
- so just writing out what I was thinking -
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Fri Nov 9 09:37:55 2007, steve, Update, PSL, head temp hiccup
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Just an other PSL-126MOPA_HTEMP hiccup.
The water chiller is at 20.00C |
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Mon Nov 12 10:53:58 2007, pkp, Update, OMC, Vertical Transfer functions
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[Norna Sam Pinkesh]
These plots were created by injected white noise into the OSEMs and reading out the response of the shadow sensors ( taking the power spectrum). We suspect |
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Mon Nov 12 15:18:34 2007, rob, Update, PSL, ISS
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After John soldered a 3.7 MHz notch filter onto the ISS board, I took a quick TF and RIN measurement. The out-of-loop RIN is attached, including a dark
noise trace, and with the gain slider at 10dB. The UGF is 35kHz with a phase margin of 30deg. John is currently doing a more thorough inspection, and |
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Mon Nov 12 23:44:19 2007, John, Update, PSL, ISS
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[quote]
After John soldered a 3.7 MHz notch filter onto the ISS board, I took a quick TF and RIN measurement. The out-of-loop RIN is attached, including a dark
noise trace, and with the gain slider at 10dB. The UGF is 35kHz with a phase margin of 30deg. John is currently doing a more thorough inspection, and |
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Tue Nov 13 14:33:40 2007, John, Update, PSL, ISS filter
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The transfer function from 'In Loop Error Point Monitor' to TP3 the filter out test point on the ISS board.
-33dB at 3.715MHz. |
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Wed Nov 14 12:47:19 2007, tobin, Update, PSL, ISS
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John, Tobin
With John's notch filter installed and the increased light on the ISS sensing diode, we were able to get a UGF of about 60 kHz with the gain slider set |
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Wed Nov 14 16:54:54 2007, pkp, Update, OMC, Much better looking vertical transfer functions
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[Norna Pinkesh]
So after Chub did his wonderful mini-surgery and removed the peek from the cables and after Norna and I aligned the whole apparatus, the following are |
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Wed Nov 14 17:50:00 2007, tobin, Update, PSL, ISS
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Here's the current wiring between the ISS and its PDs:
[table border="1"]
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Thu Nov 15 17:09:37 2007, pkp, Update, OMC, Vertical Transfer functions with no cables attached.
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[Norna Pinkesh]
The cables connecting all the electronics ( DCPDs, QPDs etc) have been removed to test for the vertical transfer function. Now the cables are sitting on |
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Thu Nov 15 18:06:06 2007, tobin, Update, Computers, alex: linux1 root file system hard disk's dying
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I just noticed that Alex made [url=http://www.ldas-sw.ligo.caltech.edu/ilog/pub/ilog.cgi?group=40m&date_to_view=11/14/2007&anchor_to_scroll_to=2007:11:14:20:00:29-aivanov]an
entry in the old ilog[/url] yesterday, saying: "[color=red][b]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.[/b][/color] 40 Gb IDE hard drive will be |
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Thu Nov 15 18:37:06 2007, tobin, Update, Computers, possible replacement for linux1's disk
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It looks like the existing disk in linux1 is a Seagate ST380013A (this can be found either via the smartctl utility or by looking at the file /proc/ide/hda/model).
It appears that you can [url=http://www.amazon.com/Seagate-ST380013ARK-Internal-Barracuda-Ultra/dp/B0000A576G/ref=pd_bbs_sr_6?ie=UTF8&s=electronics&qid=1195180463&sr=8-6]still
buy this disk from amazon[/url], though I think just about any ATA disk would work. I'll ask Steve to buy one for us. |
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Fri Nov 16 11:27:18 2007, tobin, Update, Computers, script fix
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I added a tidbit of code to "LIGOio.pm" that fixes a [url=http://lhocds.ligo-wa.caltech.edu:8000/40m/EZCA]problem with ezcastep on Linux[/url]. Scripts
such as "trianglewave" will now work on Linux.
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Fri Nov 16 14:11:26 2007, tobin, Update, Computers, op140
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| Alan called to say that Phil Ehrens will be coming by to take [b]op140[/b] off our hands. |
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Fri Nov 16 14:31:43 2007, tobin, Update, Computers, op140 disks
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| Phil Ehrens stopped by and took op140's disks. |
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Tue Nov 20 11:10:07 2007, tobin, Update, Computers, epics access from matlab
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I installed "[url=http://www.slac.stanford.edu/~strauman/labca/]labca[/url]", which allows [b]direct access to EPICS channels from within Matlab[/b]. It
comes with both Linux and Solaris binaries (and source) but I've only tried it on linux.
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Wed Nov 21 14:31:41 2007, rob, Update, PSL, FSS twiddle
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I `tweaked' the FSS path today. Here's what I did:
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Tue Nov 27 20:47:00 2007, tobin, Update, PSL, FSS
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Rana, Tobin
We looked at the RF PD signal to the FSS (siphoning off a signal via a minicircuits directional coupler) and also took an open loop transfer function of |
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Wed Nov 28 04:21:46 2007, rana, Update, PSL, FSS
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[quote]Rana, Tobin
[SIZE=1]
We looked at the RF PD signal to the FSS (siphoning off a signal via a minicircuits directional coupler) and also took an open loop transfer function of |
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Wed Nov 28 17:41:34 2007, rob, Update, PSL, FSS again
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I investigated the FSS a bit more today. I looked at the signals coming out of the FSS frequency reference, and saw that both the LO and PC drive were
distorted, non-symmetric waveforms. In addition, the LO path had a 3dB attenuator, meaning the mixer was starved. I placed mini-circuits SLP-30 filters
in both paths, and now both are nice sine waves. I also took out the 3dB att. With this work, and the CG slider maxed out at 30, the FSS open loop gain |
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Wed Nov 28 19:44:18 2007, tobin, Update, PSL, HEPA
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| I found the HEPA turned off completely. I turned it on. |
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Tue Dec 4 23:16:35 2007, tobin, Update, PSL, ISS
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I was confused to find that I could increase the ISS gain slider all the way from 15dB to 30dB without seeing much of any increase in gain in the measured
open-loop transfer function. While making these swept-sine measurements, the saturation indicator almost never tripped, indicating it was seemingly happy.
But then I noticed an odd thing: if I disable the test ("analog excitation") input, the saturation indicator trips immediately. I hooked up a scope to |
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Wed Dec 5 13:49:08 2007, alberto, Update, Electronics, RF AM PD lines monitor
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In the last weeks I’ve been working on the design of an electronic board to measure directly the power of the main spectral lines on of the RF-AM photodiode
from as many independent outputs. The idea is to have eventually a monitor channel in the CDS network for the power of each line.
Looking at at the spectrum from the RF-AM PD (see attached plot), there are 5 main lines:
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Wed Dec 5 17:49:57 2007, tobin, Update, PSL, ISS
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Attached is a plot of the ISS RIN with a variety of gain settings.
Unfortunately the dark noise is huge now--a result of the new cables & wiring? |
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Wed Dec 5 18:08:36 2007, Andrey, Update, ASC, Optical Lever laser for ETMX is installed
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A new laser with \lambda=633nm has been intalled and the mirror adjusted so that the signal hits the center of the photodetector.
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Wed Dec 5 18:22:03 2007, tobin, Update, PSL, ISS dark noise
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Attached is a plot of the dark noise spectrum of the ISS photodiodes (1) before fooling with them, (2) after replacing the 4151's with 4131's (improvement!),
and (3) after replacing the cables and changing the wiring (disaster!). |
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Wed Dec 5 20:32:51 2007, tobin, Update, PSL, ISS dark noise
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The ISS dark noise is not coming from the PD heads; the spectrum is essentially unchanged when the PD is unplugged from the ISS. Did the input opamps both
get semi-fried in the same way? (They worked so well when they were first installed.) What else changed? I'm baffled. :( |
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Thu Dec 6 19:30:43 2007, tobin, Update, PSL, ISS dark noise - 60 Hz!
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A higher resolution spectrum [attached] shows that nearly all of the excess dark noise on the ISS is in 60 Hz harmonics (with some 256 Hz harmonics too--are
these from the DAQ?).
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Fri Dec 7 18:28:30 2007, tobin, Update, Computer Scripts / Programs, compiled matlab hoses itself
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Andrey pointed out to me that some matlab functions in the Signal Processing Toolbox were dying with errors. Looking into the .m file (identified using
the "which" command), I was surprised to see binary garbage rather than glistening, clear Matlab prose. Then I noticed the directory in which it was finding
the .m file:
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Fri Dec 7 18:31:30 2007, tobin, Update, Computer Scripts / Programs, compiled matlab hoses itself
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Addendnum. The reason the linemon_mcr command was in the path was because of the user issuing the command "addpath(genpath(pwd))" where genpath(D) "returns
a path string starting in D, plus, recursively, all the subdirectories of D."
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Fri Dec 7 19:14:30 2007, tobin, Update, PSL, ISS dark noise - ground loop enlightenment
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My alleged 60 Hz harmonics were all from a ground loop created by connecting the SR785 ground to the ISS circuit ground; they disappeared when I set the
SR785 input to "floating ground." doh!
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Mon Dec 10 18:42:20 2007, tobin, Update, PSL, ISS RIN script
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I wrote a script to measure the ISS RIN. The script uses the "labca" interface (described in an [url=http://dziban.ligo.caltech.edu:40/40m/117]earlier
entry[/url]) to read and twiddle EPICS settings and mDV to get DAQ data. The script measures open loop RIN, closed loop RIN at each of several gain slider
settings, and dark noise. The dark noise is obtained by misaligning (unlocking) the PMC. The script also compares the whitened and unwhitened spectra |
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Sun Dec 16 16:52:40 2007, dmass, Update, Computers, Computer on the end Fixed
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I had Mike Pedraza look at the computer on the end (tag c21256). It was running funny, and turns out it was a bad HD.
I backed up the SURF files as attachments to their wiki entries. Nothing else seemed important so the drive was (presumably) swapped, and a clean copy |
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Mon Dec 17 11:47:13 2007, alberto, Update, Electronics, an alternative design for the RFAM monitor's filter at 33Mhz
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Since the Butterworth turned out o be rather wide-band, I tried an other configuration for the 33 MHz filter. Attached are the simulated transfer function
and the measured. As one can see, the measured peak is much broader than expected. |
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Tue Dec 18 00:51:39 2007, Andrey, Update, Computer Scripts / Programs, Results of Saturday overnight measurements 11x
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As I indicated in the previous e-log entry (#194), I made overnight measurements in XARM in the night from Saturday to Sunday.
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Tue Dec 18 16:50:35 2007, tobin, Update, SAFETY, uvex laser safety glasses defective
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A few days ago we noticed what appeared to be a blotched, speckled fracturing of the coating of the "UVEX" laser safety glasses. These are the glasses
with "transparent" (reflective to 1064nm) lenses and white frames that we keep in a box on top of a filing cabinet in the control room. Today Steve measured
the transmission of these glasses and found [b]80% transmission of 1064nm[/b] in several cases.
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Tue Dec 18 21:31:31 2007, tobin, Update, PSL, ISS RIN
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My measurements of the ISS RIN via the SR785 and via the DAQ disagree considerably. The spectral shapes are very similar, however, so I expect that a constant
factor is creeping in somewhere. Measurements taken at the PD DC monitor points using the SR785 attached. There is a lot of excess noise in the 300 Hz
- 1 kHz region. |
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Wed Dec 19 15:51:00 2007, Andrey, Update, Computer Scripts / Programs, Daytime measurements in XARM and their results 11x
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I was making measurements in XARM for three different nights. All the results agree with each other (I will put the results from the last night soon).
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Wed Dec 19 16:40:12 2007, steve, Update, SAFETY, laser safety glasses measured
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I measured the coarse transission at 1064nm of the 40m safety glasses today.
12 pieces of UVEX # LOTG-YAG/CO2 light green, all plastic construction, ADSORBANT
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Thu Dec 20 02:04:09 2007, Andrey, Update, Computer Scripts / Programs, New overnight measurements in XARM and their results 11x
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I ran in the daytime/evening time my program, changing the damping gains in suspension "position" degree of freedom for ETMX and ITMX
in the interval from 1.00 to 3.75 with the step 0.25 (see entry # 201).
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