| ID |
Date |
Author |
Type |
Category |
Subject |
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9
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Tue Oct 23 09:01:00 2007 |
rana | Other | OMC | PZT calibration/ transfer function. |
Are you sure that the error signal sweep is not saturated on the top ends? This is usually the downfall
of this calibration method. |
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10
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Tue Oct 23 11:08:20 2007 |
steve | Other | General | brush fires |
There are big brush fires around LA
40 days plot show no effect in the 40m lab |
| Attachment 1: brushfires.jpg
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11
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Wed Oct 24 01:43:32 2007 |
Andrey Rodionov | Other | General | PDF-file -> Will report about first results for XARM during Wednesday meeting |
Here is the pdf-file with some graphs showing first results for XARM optimization.
We will discuss alltogether during our Wednesday meeting which starts at 2.40PM. Probably it would be necessary to project this pdf-file to the big screen,
so someone should bring laptop and probably connect it to the projector. I do not have a laptop.
See you on that meeting. |
| Attachment 1: Andrey_October_24.pdf
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12
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Wed Oct 24 08:58:09 2007 |
steve | Other | PSL | laser headtemp is up |
C1:PSL-126MOPA_HTEMP is 19.3C
Half of the chiller's air intake was covered by loose paper |
| Attachment 1: htempup.jpg
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14
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Thu Oct 25 17:52:45 2007 |
waldman | Other | OMC | OMCs with QPDs |
[Rich, Chub, Pinkesh, Sam]
Yesterday we got the QPD, OTAS, and PZT cabling harness integrated with the OMC. We found a few things out, not all of them good. The QPDs went on no problem and could be fairly well aligned by hand. We "aligned" them by looking at all four channels of the QPD on the scope and seeing that there is signal. Since the beam is omega = 0.5 mm, this is a reasonable adjustment. We then connected the OTAS connector to the OTAS and found that the heater on the OTAS was bonded on about 30 degrees rotated from its intended position. This rotated the connector into the beam and caused a visible amount of scattering. This wasn't really a disaster until I removed the connector from the heater and broke the heater off of the aluminum parts of the OTAS. Two steps backwards, one step forward. After the OMC, OMC-SUS integration test we will re-bond the heater to the aluminum using VacSeal. In the meantime, the OMC has been moved to Bridge 056 for integration with the OMC-SUS. More on that as we make progress. |
|
16
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Thu Oct 25 23:35:36 2007 |
waldman | Other | OMC | Hang the OMC! |
[Pinkesh, Sam]
We tried, convicted and hung the OMC today. The OMC was found guilty of being overweight, and unsymmetrically balanced. The unsymmetry was kind of expected and was corrected with a hefty stack of counterweights positioned over the counterweighting holes. The stacks will be measured at some future date and correctly sized objects machined. The overweightness showed up when the level hanging breadboard was about 5 mm low. This showed up in the board height above the table as well as the OSEM flag positions within their holes. The problem was remedied with a liposuction of the intermediate mass. We removed both small vertical cylinder weights that Chris added, and then we removed the heavy steel transverse weight that can be used to adjust the tip around the long axis (I forgot what its called).
The top of the breadboard ended up about 154 mm off the table. The breadboard is 39 mm thick, and the optics are centered (30 - 12.7) = 17.3 mm below the surface for a as hanging beams height of 154 -39 - 17.3 = 97.7 mm or about an 0.150 inches lower than we were aiming for. Can I get a refund?
We screwed up in multiple ways:
- The slotted disks that capture the wires do not have the alignment bore used to center the wire in the hole
- We didn't correctly route the far field QPD cable so it runs funny
- We didn't have a tool which could be used to get two of the DCPD preamp box mounting screws (which are M3's chub!)
- We don't have the cable clamps to tie off the electrical cables to the intermediate mass
- We don't have any of the cabling from the OMC-SUS top to the rack so we can't test anything
- We haven't uploaded pretty pictures for all to see
We left the OMC partially suspended by the OMC-SUS and partly resting on the installation lab jacks which are currently acting as EQ stops. After we fix the cabling we will more permanently hang it. PS, It looks like the REFL beam extraction will be tricky so we need to get on that.... |
| Attachment 1: IMG_1483.jpg
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| Attachment 2: IMG_1481.jpg
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19
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Fri Oct 26 17:34:43 2007 |
waldman | Other | OMC | OMC + earthquake stops |
[Chub, chris, Pinkesh, Sam]
Last night we hugn the OMC for the first time and came up with a bunch of pictures and some problems. Today we address some of the problems and, of course, make new problems. We replaced the flat slotted disks with the fitted slotted disks that are made to fit into the counterbore of the breadboard. This changed the balance slightly and required a more symmetric distribution of mass. It probably did not change the total mass very much. We did find that the amount of cable hanging down strongly affected the breadboard balance and may also have contributed to the changing balance.
We also attached earthquake stops and ran into a few problems:
- The bottom plate of the EQ stops is too thick so that it bumps into the tombstones
- The vertical member on the "waist" EQ stops is too close to the breadboard, possibly interfering with the REFL beam
- The "waist" EQ stops are made from a thin plate that doesn't have enough thickness to mount helicoils in
- Helicoil weren't loaded in the correct bottom EQ stops
- The DCPD cable loops over the end EQ stop looking nasty but not actually making contact
However, with a little bit of jimmying, the EQ stops are arrayed at all points within a few mm of the breadboard. Meanwhile, Chub has cabled up all the satellite modules and DCPD modules and Pinkesh is working on getting data into the digital system so we can start playing games. Tonight, I intend to mount a laser in Rana's lab and fiber couple a beam into the 056 room so we can start testing the suspended OMC. |
|
29
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Tue Oct 30 00:47:29 2007 |
rana | Other | IOO | MC Ringdowns |
I did a bunch of MC ringdown measurements using the PD that Rob set up. The idea is to put a fast PD (PDA255)
looking at the transmission through MC2 after focusing by a fast lens. The input to the MC is turned off fast
by flipping the sign of the FSS (Andri Gretarsson's technique).
With the laptop sitting on the MC can, its easy to repeat many ringdowns fast:
- Turn off the MC autolocker. Relock the MC with only the acquisition settings; no boosts
and no RGs. This makes it re-acquire fast. Turn the MC-WFS gain down to 0.001 so that
it keeps it slowly aligned but does not drift off when you lose lock.
- Use low-ish gain on the FSS. 10 dB lower than nominal is fine.
- Setup the o'scope (100 MHz BW or greater) to do single shot trigger on the MC2 trans.
- Flip FSS sign.
- Quickly flip sign back and waggle common gain to get FSS to stop oscillating. MC
should relock in seconds.
Clearly one can scriptify this all just by hooking up the scope to the ethernet port.
Attached are a bunch of PNG of the ringdowns as well as a tarball with the actual data. A sugar
napoleon to whomever can explain the 7 us period of the wiggle before the vent! |
| Attachment 1: tek00000.png
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| Attachment 2: tek00001.png
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| Attachment 3: tek00004.png
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| Attachment 4: MC2ringdown.tar.gz
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33
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Tue Oct 30 20:15:24 2007 |
tobin | Other | Environment | earthquake |
Rana, Tobin
Largish (M5.6) earthquake in San Francisco sent our optics swinging. |
|
35
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Wed Oct 31 08:34:35 2007 |
rana | Other | IOO | loss measurements |
In the end, we were unable to get a good scatter measurement just because we ran out of steam. The idea was to get a frame
grab image of MC2 but that involves getting an unsaturated image.
In the end we settle for the ringdowns, Rob's (so far unlogged) cavity pole measurement, and the MC transmission numbers. They
all point to ~100-150 ppm scatter loss per mirror. We'll see what happens after wiping. |
|
37
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Wed Oct 31 09:45:28 2007 |
waldman | Other | OMC | Resolution to DAQland saga |
[Jay, Sam]
We did a rough accounting for the linear delay this morning and it comes out more or less correct. The 10 kHz 3rd order butterworth AA/AI filter gives ~90 degrees of phase at 6 kHz, or 42 microseconds. Taken together, the two AA and AI filters are worth 80 microseconds. The 1.5 sample digital delay is worth 1.5/32768 = 45 microseconds. The remaining 160 - 125 = 35 microseconds is most likely taken up by the 64 kHz to 32 kHz decimation routine, assuming this isn't accounted for already in the 1.5 sample digital delay.
It remains to be seen whether this phase delay is good enough to lock the laser to the OMC cavity |
|
42
|
Wed Oct 31 23:55:17 2007 |
waldman | Other | OMC | QPD tests |
The 4 QPDs for the OMC have been installed in the 056 at the test setup. All 4 QPDs work and have medm screens located under C2TPT. The breadboard mounted QPDs are not very well centered so their signal is somewhat crappy. But all 4 QPDs definitely see plenty of light. I include light and dark spectra below. QPDs 1-2 are table-mounted and QPD 2 is labeled with a bit of blue tape. QDPs 3-4 are mounted on the OMC. QPD3 is the near field detector and QPD4 is the far field. In other words, QPD3 is closest to the input coupler and QPD4 is farthest.
Included below are some spectra of the QPDs with and without light. For QPDs 1 & 2, the light source is just room lights, while 3&4 have the laser in the nominal OMC configuration with a few mWs as source. The noise at 100 Hz is about 100 microvolts / rtHz. If I recall correctly, the QPDs have 5 kOhm transimpedance (right Rich?) so this is 20 nanoamps / rtHz of current noise at the QPD. |
| Attachment 1: QPD_SignalSpectrum.pdf
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| Attachment 2: QPD_SignalSpectrum.gif
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43
|
Thu Nov 1 01:28:04 2007 |
waldman | Other | OMC | First digital lock of OMC |
[Pinkesh, Sam]
We locked a fiber based NPRO to the suspended OMC tonight using the TPT digital control system. To control the laser frequency, we took the PZT AI output and ran it on a BNC cable down the hallway to the Thorlabs HV box. The Thorlabs is a singled ended unit so we connected the AI positive terminal only and grounded the BNC to the AI shield. We could get a -6 to 1.5 V throw in this method which fed into the 10 k resisotr + 9 V battery at the input of the HV box. The HV out ran to the NPRO PZT fast input.
We derived our error signal from a PDA255 in reflection with a 29.5 MHz PDH lock. The signal feeds into one of the unused Tip/Tilt AA channels and is passed to the PZT LSC drive through the TPT_PDH1 filter bank. In the PZT_LSC filter we put a single pole at 1 Hz which, together with the phase we mentioned the other night (180 degrees at 3 kHz) should allow a 1 kHz-ish loop. In practice, as shown below, we got a 650 Hz UGF with 45 degrees of phase margin and about 6 dB of gain margin.
The Lower figure shows the error point spectrum with 3 settings. REF0 in blue shows lots of gain peaking at 1.5 kHz-ish, just where its expected - the gain was -40. The REF1 has gain of -20 and shows no gain peaking. The current trace in red shows some gain peaking cuz the alignment is better but it also has included a 1^2:20^2 boost which totally crushes the low frequency noise. We should do a better loop sweep after getting the alignment right so we can see how much boost it will really take.
Just for fun, we are leaving it locked overnight and recording the PZT_LSC data for posterity. |
| Attachment 1: 071101_PZT_firstLoopSweep.pdf
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| Attachment 2: 071101_PZT_firstLoopSweep.gif
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| Attachment 3: 071101_OMC_FirstLock_spectra.pdf
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| Attachment 4: 071101_OMC_FirstLock_spectra.gif
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32
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Tue Oct 30 19:32:13 2007 |
tobin | Problem Fixed | Computers | conlogger restarted |
| I noticed that the conlogger wasn't running. It looks like it hasn't been running since October 11th. I modified the restart_conlogger script to insist that it run on op340m instead of op440m, and then ran it on op340m. |
|
34
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Wed Oct 31 08:33:54 2007 |
rana | Problem Fixed | SUS | Vent measurements |
There was a power outage during the day yesterday; whoever was around should post something here about the
exact times. Andrey and David and Tobin got the computers back up - there were some hiccups which you can
read about in David's forthcoming elog entry.
We restarted a few of the locking scripts on op340m: FSSSlowServo, MCautolocker. Along with the updates
to the cold restart procedures we have to put an entry in there for op340m and a list of what scripts
to restart.
David tuned up the FSS Slow PID parameters a little; he and Andrey will log some entry about the proper
PID recipe very soon. We tested the new settings and the step response looks good.
We got the MC locking with no fuss. The 5.6 EQ in San Francisco tripped all of the watchdogs and I upped
the trip levels to keep them OK. We should hound Rob relentlessly to put the watchdog rampdown.pl into
the crontab for op340m. |
|
36
|
Wed Oct 31 08:38:35 2007 |
rana | Problem Fixed | IOO | MC autolocker |
The MC was having some trouble staying locked yesterday. I tracked this down to some steps in the last
half of the mcup script; not sure exactly which ones.
It was doing something that made the FAST of the PSL go to a rail too fast for the SLOW to fix.
So, I broke the script in half so that the autolocker only runs the first part. We'll need to
fix this before any CM locking can occur.
We also need someone to take a look at the FSS Autolocker; its ill. |
|
2
|
Thu Oct 18 14:52:35 2007 |
rana | Routine | ASC | test |
test
X-(:P;(:)) |
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3
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Thu Oct 18 15:03:14 2007 |
ajw | Routine | General | this is only a test |
 |
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7
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Mon Oct 22 12:02:59 2007 |
ajw | Routine | General | STACIS as microseismic shaker |
In case we ever want to use our Stacis systems as shakers, check this:
link |
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15
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Thu Oct 25 22:02:58 2007 |
rob | Routine | PSL | HEPAs maxed |
| In light of the SoCal fires, I turned the PSL HEPAs up to 100%. |
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17
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Fri Oct 26 09:10:17 2007 |
steve | Routine | PEM | PEM &PSL trend |
The fires are out, lab particle counts are up.
Psl HEPAs are at 100% and mobel HEPAs are just turned on
20 days plot and 5 hrs plot below |
| Attachment 1: counts&psl.jpg
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| Attachment 2: 5dcounts.jpg
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18
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Fri Oct 26 16:19:29 2007 |
Tobin Fricke | Routine | IOO | MC resonances |
We would like to measure the absorption of the mode cleaner optics. The plan is to repeat <a href="http://ilog.ligo-wa.caltech.edu:7285/mLIGO/Cleaning_the_Mode_Cleaner">Valera's experiment</a> in which we track the MC's thermal resonances to infer their power absorption. Last night Rana and I hooked up a lock-in amplifier to heterodyne the MC servo signal by 28 kHz and piped the output into an ADC using the MC_AO channel. We did not find any resonances.
Valera recommends we drive the POS of the three MC optics with bandlimited noise to excite the resonances. |
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23
|
Mon Oct 29 09:16:31 2007 |
steve | Routine | VAC | the rga is back |
We had no filament current since last power glitch of Oct. 8, 2007
First I thought that the filament was lost, but it was only bad contact.
The rga head pins were oxidized. Rga was turned back on last Friday.
It's temp is 55.3C normal |
| Attachment 1: rgaisback.jpg
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24
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Mon Oct 29 09:46:50 2007 |
steve | Routine | VAC | vac & pem trend |
Pumpdown 64 pumped by maglev for 125 days
pd64-m-d125
Rob, can you tell me, when did the fire start on this plot? |
| Attachment 1: pd64md125.jpg
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31
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Tue Oct 30 16:55:40 2007 |
tobin | Routine | | Drag-wiping perfected |
Steve, Tobin
Steve procured an assortment of syringes from the bio storeroom and we practiced drag-wiping the SOS in the flow bench. Using a 50 microliter Hamilton syringe to deliver 16 microliters of methanol seems perfect for drag-wiping the small optics. Drag-wiping in the downward direction seems to work very well, since we can squirt the optic directly in the center, and the (half) piece of kodak lens tissue fits easily between the bottom two earthquake stops. |
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38
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Wed Oct 31 10:31:23 2007 |
Andrey Rodionov | Routine | VAC | Venting is in progress |
We (Steve, David, Andrey) started venting the vacuum system at 9.50AM Wednesday morning. |
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39
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Wed Oct 31 15:02:59 2007 |
tobin | Routine | IOO | Mode Cleaner Mode Tracking |
| I processed the heterodyned mode cleaner data yesterday, tracking the three 28 kHz modes corresponding to MC1, MC2, and MC3. Unfortuntately the effect of our MC power chopping is totally swamped by ambient temperature changes. Attached are two plots, one with the tracked mode frequencies, and the other containing dataviewer trends with the MC transmitted power and the room temperature. Additionally, the matlab scripts are attached in a zip file. |
| Attachment 1: mode-track.pdf
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| Attachment 2: trends.pdf
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| Attachment 3: mcmodetrack.zip
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41
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Wed Oct 31 19:26:08 2007 |
Andrey Rodionov | Routine | General | Photographs of "Mode-Cleaner Entrance" |
Here are the pictures of "inside the chamber". |
| Attachment 1: MC-Pictures-1.pdf
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| Attachment 2: MC-Pictures-2.pdf
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| Attachment 3: MC-Pictures-3.pdf
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| Attachment 4: MC-Pictures-4.pdf
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| Attachment 5: MC-Pictures-5.pdf
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| Attachment 6: MC-Pictures-6.pdf
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| Attachment 7: MC-Pictures-7.pdf
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| Attachment 8: MC-Pictures-8.pdf
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| Attachment 9: MC-Pictures-9.pdf
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44
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Thu Nov 1 09:17:27 2007 |
steve | Routine | VAC | vent 64 |
Yesterday before vent I could not lock MC, therfore I could not measure the
transmitted power at MC2
The vent went well. We had lots of help.
We could not find the Nikon D40
PLEASE BORROW THINGS when taking them away
and bring them back promtly.
The laser was turned off for better visibility.
I see clean room frorks laying around here and there.
Please put them away so we do not carry excess particles into the chamber. |
| Attachment 1: vent64.jpg
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13
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Thu Oct 25 00:01:21 2007 |
rana | Software Installation | CDS | GEO DV => LIGO DV |
Martin Hewitson of GEO600 fame has modified the cool GEO DV
to work with the LIGO NDS system with some NDS advice from Rolf (who's over in Germany this week).
I've moved it onto the 40m CDS system and installed it on the AdhikariLab computer named 'django'. It worked immediately.
I modified the main .m file to include the 40m's NDS server. When you run it you have to include the path to the NDS
client written by Ben Johnson.
The attached is a screenshot of it working on a Mac; it looks as cool on Linux.
Its installed in /cvs/cds/caltech/apps/ligoDV/. In matlab you navigate to that directory and then
type addpath('/cvs/cds/caltech/apps/linux/UNIX_NDS_Client_beta2/') to add the NDS client.
On the Solaris machines, type type addpath('/cvs/cds/caltech/apps/solaris9/UNIX_NDS_Client_beta2/') instead.
Then type ligoDV to start it up. Then click away and have fun.
In the example I've selected C1:PEM-BS_ACC_EAST_Z and plotted its specgram.
 |
| Attachment 1: Picture_1.png
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25
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Mon Oct 29 11:07:22 2007 |
waldman | Software Installation | OMC | Software install on OMS |
[Alex, Sam]
We spent a little time this morning working on OMS and getting things restarted. A few changes were made. 1) We put openmotif on OMS so that the burtrb doesn't throw that crappy libXm any more. 2) We upgraded OMS to a 32 kHz sampling rate from 2 kHz. All the filters will have to be changed. We also added a PDH filter path to maybe feedback PDH signals cuz that will be cool. Maybe someday I will write up the very cool channel adding procedure. |
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28
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Mon Oct 29 23:25:42 2007 |
tobin | Software Installation | CDS | frames mounted |
I mounted the frames directory on mafalda and linux3. It's intentionally not listed in the /etc/fstab so that an fb crash won't prevent the controls machines from booting. The command to mount the frames directory is:
mount fb40m:/frames/frames /frames |
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46
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Thu Nov 1 16:34:47 2007 |
Andrey Rodionov | Summary | Computers | Limitation on attachment size of E-LOG |
I discovered yesterday when I was attaching photos that it is NOT possible to attach files whose size is 10Mb or more. Therefore, 10Mb or something very close to that value is the limit. |
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47
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Thu Nov 1 16:42:48 2007 |
Andrey Rodionov | Summary | Environment | End of Daylight Saving Time this weekend |
Useful information for everyone, as a friendly reminder:
According to the web-page
http://www.energy.ca.gov/daylightsaving.html,
this coming weekend there will be the end of Daylight Saving Time.
Clocks will be adjusted backward one hour. |
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56
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Thu Nov 1 20:03:00 2007 |
Andrey Rodionov | Summary | Photos | Procedure "Drop and Drag" in pictures |
|
| Attachment 1: DSC_0072.JPG
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| Attachment 2: DSC_0083.JPG
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| Attachment 3: DSC_0099.JPG
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| Attachment 4: DSC_0100.JPG
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58
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Fri Nov 2 12:18:47 2007 |
waldman | Summary | OMC | Locked OMC with DCPD |
[Rich, Sam]
We locked the OMC and look at the signal on the DCPD. Plots included. |
| Attachment 1: 071102_OMC_LockedDCPD.gif
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| Attachment 2: 071102_OMC_LockedDCPD.pdf
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59
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Sat Nov 3 16:20:43 2007 |
waldman | Summary | OMC | A good day's work |
I followed up yesterday's test of the PZT with a whole mess of characterizations of the PZT control and finished the day by locking the OMC with a PZT dither lock and a 600 Hz loop. I haven't analyzed any of the data yet, so its not calibrated in physical units and etc. etc. etc. Since a lot of the sweeps below are of a "drive the PZT, look at the PDH signal" nature, a proper analysis will require taking out the loop and calibrating the signals, which alas, I haven't done. Nonetheless, I include all the plots because they are pretty. The files included below are:
- DitherLock_sweep: Sweep of the IN2/IN1 for the dither lock error point showing 600 Hz UGF
- HiResPZTDither_sweep: Sweep of the PZT dither input compared to the PDH error signal. I restarted the front end before the sweep was finished accounting for the blip.
- HiResPZTDither_sweep2: Finish of the PZT dither sweep
More will be posted later. |
| Attachment 1: 071103_DitherLock_sweep.png
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| Attachment 2: 071103_DitherLock_sweep.pdf
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| Attachment 3: 071103_HiResPZTDither_sweep.png
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| Attachment 4: 071103_HiResPZTDither_sweep.pdf
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| Attachment 5: 071103_HiResPZTDither_sweep2.png
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| Attachment 6: 071103_HiResPZTDither_sweep2.pdf
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65
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Tue Nov 6 09:14:37 2007 |
steve | Summary | VAC | pump down 65 |
8 hr plot,
precondition: 5 days at atm,
vent objective: drag wiping mc1, mc2 & mc3 accomplished,
hardware changes: IOO access connector, mc2 chamber door south & west
were removed and reinstalled
pump down mode: slow to avoid steering up dust
One roughing pump was used with closed down valve position in the first 4 hrs
Andrey was very helpful |
| Attachment 1: pd65.jpg
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66
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Tue Nov 6 09:45:22 2007 |
steve | Summary | SUS | vent sus trend |
The mc optics dragwippings were done by locking optics by eq stops and rotating-moving
cages so access were good. This technic worked well with mc1 & mc2
MC3 osems were reoriented only. |
| Attachment 1: ventsustrend.jpg
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104
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Thu Nov 15 04:18:11 2007 |
John | Summary | PSL | PMC cavity pole measurements |
In connection with our work on the ISS I attempted to measure the PMC cavity pole.
I swept the PMC PZT and looked at the transmission through the cavity on the ISS Monitor diode (which is now back on the table, feel free to remove it again tomorrow).
To avoid thermal effects I reduced the laser power using the half wave plate at the laser ouput (rotated from 6 deg to 340deg).
I swept the PZT using the triangle wave command "trianglewave C1: PSL-PMC_RAMP -3.5 3.3 20 200". I noticed that the functional form of the resonances deteriorated over the duration of the excitation. Each sweep was able to capture just over one FSR. The resonances were a little close to the 'points' of the triangle wave for my liking although I don't think PZT hysteresis was a big factor.
Looking at the data the peaks are not of uniform width across a sweep or between consecutive sweeps. Hence any results from this mesurement are not particularly useful. I can't be sure if this was due to misalignments, thermal effects, higher order mode content or some other affect.
Rob suggests sweeping the laser frequency using the NPRO PZT instead. |
| Attachment 1: Peaks.jpg
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108
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Thu Nov 15 18:36:48 2007 |
John | Summary | | PSL table work |
| I've rotated the lambda/2 plate to 340deg (from 6 deg) and blocked one arm of the Mach-Zender. Undo both if you need to. |
|
116
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Tue Nov 20 10:11:33 2007 |
John | Summary | PSL | PMC pole measurements |
We measured the PMC pole in the following way.
1. Reduced laser power by rotating lambda/2 plate at laser output. Thermal effects in the PZT distort resonance peaks. Reducing power too much leads to problems with digitisation error.
2. Sweep NPRO PZT (C1: PSL-FSS_INOFFSET) using trianglewave. Record ramp, PMC transmission and reference cavity transmission ('C1: PSL-FSS_FAST','C1: PSL-ISS_INMONPD_F','C1: PSL-FSS_RCTRANSPD_F).
3. Since the PZT cannot sweep a full FSR in the PMC we looked at the sideband resonances within the reference cavity to calibrate the actuator.
Result: 7.35 +/- 0.22 MHz/V
4. Use #3 to calibrate the x axis of the PMC transmission.
5. Fit PMC resoances to an Airy function to get finesse. Take an average, weighted according to the resnorm. Calculate cavity pole frequency.
Result: 380kHz +/- 59kHz. This corresponds to a finesse of ~936. According to this plot the nominal pole is at 488kHz and the finesse is 732.
This is by no means a definitive measurement due to the misshapen resonance peaks recorded. |
| Attachment 1: FittedPMCPeak.jpg
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119
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Tue Nov 20 18:02:54 2007 |
John | Summary | Computers | PSL_Main screen |
| I've updated the PSL_MAIN screen. The old version may be found in cvs/cds/caltech/medm/old/medm/psl. |
| Attachment 1: PSL_Screen.tif
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144
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Fri Nov 30 11:22:22 2007 |
ajw | Summary | CDS | GEO DV => LIGO DV |
| Quote: | Martin Hewitson of GEO600 fame has modified the cool GEO DV
to work with the LIGO NDS system with some NDS advice from Rolf (who's over in Germany this week).
I've moved it onto the 40m CDS system and installed it on the AdhikariLab computer named 'django'. It worked immediately.
I modified the main .m file to include the 40m's NDS server. When you run it you have to include the path to the NDS
client written by Ben Johnson.
The attached is a screenshot of it working on a Mac; it looks as cool on Linux.
Its installed in /cvs/cds/caltech/apps/ligoDV/. In matlab you navigate to that directory and then
type addpath('/cvs/cds/caltech/apps/linux/UNIX_NDS_Client_beta2/') to add the NDS client.
On the Solaris machines, type type addpath('/cvs/cds/caltech/apps/solaris9/UNIX_NDS_Client_beta2/') instead.
Then type ligoDV to start it up. Then click away and have fun.
In the example I've selected C1:PEM-BS_ACC_EAST_Z and plotted its specgram.
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Download and installation instructions, as well as a few examples for use
can be found here (typical lsc username and password):
https://www.gravity.phy.syr.edu/dokuwiki/doku.php?id=ligodv:home
https://www.gravity.phy.syr.edu/dokuwiki/doku.php?id=ligodv:downloading_the_ligodv_software |
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Fri Nov 30 20:13:57 2007 |
dmass | Summary | General | HeNe UniPhase Laser |
Data for the Uniphase 1.9 mW HeNe laser (labeled: "051507 From ISCT-BS") SN: 1284131 Model: 1103P
I used the Photon Beamscanner to obtain all data, then fit w(z) as shown on the plot with parameters w_0, z_R, and hidden parameter delta,
where z = delta + x, z is waist distance, x is distance from the laser.
Copies of the matlab code used to fit (/plot) are attached in .zip below. |
| Attachment 1: Matlabcode.zip
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| Attachment 2: UniPhaseWaist.jpg
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Thu Dec 6 15:22:42 2007 |
Andrey | Summary | Electronics | Pictures of the inside of He-Ne laser |
Steve gave me an old "dead" He-Ne laser that long time ago was used for ETMX optical lever.
I dismantled it (cutting the metallic enclosure with a metallic saw), and these are two pictures of what is inside. |
| Attachment 1: DSC_0226.JPG
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| Attachment 2: DSC_0228.JPG
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Fri Dec 7 00:02:26 2007 |
rana | Summary | IOO | MC/FSS Frequency Noise |
The FSS frequency noise is not very bad.
I compared the MC_F spectra between Hanford and the 40m using DTT and its 'User NDS' option.
After Sam, Jenne, and DavidM installed the new MC Servo some time ago, the MC_F spectrum here
has had some whitening before it goes into the DAQ (on board; same as LLO & LHO). The tuning
coefficient of the VCO is also basically the same between all PSLs since everyone has the same
chip in the VCO driver.
Therefore, at the frequencies where the MC gain is more than ~4, the MC_F signal calibration is
the same here as anywhere. Since its the servo control signal, its basically a measure of the
frequency noise incident on the MC -- its just what comes out of the FSS with the table noise on
top. At low frequencies (< 100 Hz) its a measure of the motion of the MC mirrors.
Above 200 Hz ours is the same as theirs; except for the enormous power line spikes. I think that's
either all on the light. But our acoustics are better and the noise above 1 kHz levels off at the
same flat floor (the phase noise of the VCO) as H1. The huge lump around 100 Hz is the MC2 DAC noise and
it goes down to the H1 levels when we flip on the dewhites. The giant excess from 5-50 Hz is just the fact
that our stacks don't do much until 20-30 Hz.
So we can stop blaming the FSS and move on with life as soon as Tobin gets the ISS back in shape. |
| Attachment 1: fly.pdf
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Tue Dec 18 23:41:00 2007 |
Andrey | Summary | Computer Scripts / Programs | Results of Mon/Tue overnight measurements (entry #194) |
Here I inform our community about the results of the measurements of RMS values in XARM during the previous night from Monday to Tuesday (I announced those measurements in ELOG entry #194).
All the plots in today's report seem to agree well with the analogous plots from the night from Saturday to Sunday (those results are given in ELOG entry # 195).
All the intervals in which RMS have been calculated are the same as in yesterday's ELOG entry #195.
I plotted three results for RMS in the abovementioned three intervals in three different ways:
1) view from the top in the axes (Q_{ITMX}+Q_{ETMX})/2 and (Q_{ITMX}-Q_{ETMX}) -> first three graphs (attachments 1 -3);
2) view from the side in the same sum- and difference-axes -> next three graphs (attachments 4-6);
3) view from the side in Q_{ITMX} and Q_{ETMX} axes -> next three graphs (attachments 7-9, also attch. 12), above accelerometer spectra (attachments 10-11).
Also, I compared the ground noise level by comparing spectra of accelerometer signals at different times during that night. As a reminder, before my disease I installed one accelerometer near ITMX and another accelerometer near ETMX (see entries 161 and 172 in ELOG). The plots of ratios of accelerometer signals at different times (pairs of times that were used: 11PM and 2AM, 11PM and 5AM, 11PM and 8AM) are given below, see attachments 10-11. The program was running from 11PM on Monday till 9AM on Tuesday.
As I explained in the previous ELOG entry # 198, tonight I am taking experimental data in the narrowere interval from 1.00 to 4.50 with a smaller step 0.25. |
| Attachment 1: RMS_08HZ_Top_View.png
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| Attachment 2: RMS_3HZ_Top_View.png
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| Attachment 3: RMS_broad_Top_View.png
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| Attachment 4: RMS_08HZ_Side_View.png
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| Attachment 5: RMS_3HZ_Side_View.png
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| Attachment 6: RMS_broad_Side_View.png
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| Attachment 7: RMS_08HZ_Q_E_Q_I_Axes.png
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| Attachment 8: RMS_3HZ_Q_E_Q_I_Axes.png
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| Attachment 9: RMS_broad_Q_E_Q_I_Axes.png
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| Attachment 10: Accelerometer_ITMX.png
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| Attachment 11: Accelerometer_ETMX.png
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| Attachment 12: RMS_broad_Q_E_Q_I_Axes.png
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Wed Dec 19 16:07:37 2007 |
Andrey | Summary | Computer Scripts / Programs | Results of overnight measurements Tue/Wed night (entry #198) |
As indicated in ELOG entry 198, I was making overnight measurements during last night from Tuesday to Wednesday.
I was changing the suspension damping gain in ETMX and ITMX in "position" degree of freedom between values of 1.00 and 4.50 with the step 0.25.
Results for RMS of peaks (A) at 0.8Hz, (B) at about 3.0Hz and (C) in the range from 0.6Hz to 3.7Hz ("RMS in a broad interval") are given below:
I plotted three results for RMS in the abovementioned three intervals in three different ways:
1) view from the top in the axes (Q_{ITMX}+Q_{ETMX})/2 and (Q_{ITMX}-Q_{ETMX}) -> first three graphs (attachments 1 -3);
2) view from the side in the same sum- and difference-axes -> next three graphs (attachments 4-6);
3) view from the side in Q_{ITMX} and Q_{ETMX} axes -> next three graphs (attachments 7-9)
Attachments 10 and 11 show ratios of accelerometer signals at different times of the night/morning.
A little discussion about these graphs:
1) The areas of minima and of rapid growth are the same for all the measurements during all three nights.
2) Tonight there was a strange spike for the values of Q_{ETMX}=2.5 and Q_{ITMX}=4.0. I interpret that as an error of experiment.
3) On all the plots from all three nights there is a wide area of minimum on the plots for RMS at 0.8Hz and for "RMS in the broad interval",
and the graph for "RMS at 3Hz" indicates a clearer minimum in a localized area for Q_{ITMX}=2+-1, Q_{ETMX}=2+-1. Note that this area 2+-1
is included into the wide region of minimum for "RMS at 0.8Hz" and "RMS in a broad range".
Therefore, my guess at this stage is that we can choose the optimized value of suspension damping gains for both Q_{ITMX} and Q_{ETMX} somewhere
around 2+-1. I would like to make another overnight measurement (tonight) in that narrowed region with a small step to have more certainty.
By the way, I realized that I was a little bit careless and at some plots Q_I stands for {Q_ITMX}, and Q_E stands for Q_{ETMX}.
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| Attachment 1: RMS_08Hz_Top_view.png
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| Attachment 2: RMS_3Hz_Top_view.png
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| Attachment 3: RMS_broad_Top_view.png
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| Attachment 4: RMS_08Hz_Side_view.png
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| Attachment 5: RMS_3Hz_Side_view.png
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| Attachment 6: RMS_broadband_Side_view.png
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| Attachment 7: RMS_08Hz_Q_I-Q_E-axes.png
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| Attachment 8: RMS_3Hz_Q_I-Q_E-axes.png
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| Attachment 9: RMS_broadband_Q_I-Q_E-axes.png
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| Attachment 10: Accelerom_ETMX.png
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| Attachment 11: Accelerom_ITMX.png
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Thu Dec 20 21:58:28 2007 |
Andrey | Summary | Computer Scripts / Programs | Results for 2 previous XARM measurements have been added |
I attached results (plots) of yesterday's daytime and overnight measurements to the initial reports about those measurements.
These are ELOG entries # 201 and # 205. |