Test results of new REFL165 (the first attachment)
- The resonant freq 166.2MHz, Q=57 (previous Q was ~7)
- If we believe the TF measurement, the transimpedance at the resonance is 7.8k [V/A] and the shotnoise intercept current of ~1mA.
The linearity of the peak was confirmed by changing the modulation level of the beam.
- There is a riddle: the white light test indicates 4.5k [V/A] and 2.8mA for those numbers.
There are big descrepancies from those by the TF measurements.
Further analysis of the descrepancies:
Using the noise measurements with different DC current levels, the transimpedance for each frequency can be reconstructed.
Does this indicate the satiration by the white light???
- The TF measurement shows consistent mag&phase relationship at the resonance (c.f. LISO fit).
So this steep resonance is not an artifact by a noise or glitch but the real structure of the electronics.
- The TF measurement has been done with the photocurrent of ~0.3mA, while the transimpedance measurement
with the white light illumination has the practical effect only when the DC photocurrent is larger than 1mA
because of the circuit noise. Does this higher photo current affected the resonance?
- The off-resonant transimpedance agree with the TF measurement as far as we can see with those measurements.
This may mean that the actual resonant structure has been affected in the white light measurement.
(i.e. not the saturation of the RF opamp which causes the change of the gain at any freq.)
Is the above mentioned higher DC current causing the change of the diode capacitance or other property of the diode or the inductors???
Unless the bias feedback circuit has been tuned for the 1 mm diode, its possible that you are seeing some C(V) effects. Its easy to check by looking at the phase response at 165 MHz v. the DC photocurrent. Then the feedback or feedforward gain can be tuned.
New AG4395, sn MY41101114 for West Bridge Labs was delivered. For the test purpose it is at the 40m now.
I made a series of tests in order to find anything broken.
Network analyzer test
- RF out / Rch test
RF out directly connected to R input channel.
The received power at the R-ch was measured while the output was swept from 10Hz to 500MHz.
The RF power was changed from -50dBm to +15dBm with +10dBm increment (but the last one).
The attenuator setting was changed from 50dB to 0dB.
=> The configured output power was properly detected by the R channel.
=> RF output is producing the signal properly. R-ch is detecting the produced signal properly.
- Ach/Bch test
Same test as above for Ach and Bch
=> Same result as above
=> A-ch and B-ch are detecting the produced signal properly.
- Transfer function test
Connect a power splitter to the RF out. Detect the split signals by R-ch and A-ch
=> Measurement is at around 0dB +/- 1dB up to 500MHz.
Same measurement for B-ch
=> Same result
=> A/R and B/R indicates proper transfer function measurements.
RF out was split in to two. One was connected to R-ch. The other was connected to A-ch.
The thru response calibration was run.
=> The thru calibration was performed properly.
- Practical tranfer function measurements.
In the above calibration setup, various RF filters were inserted in the Ach path.
The measured data was extracted via GPIB connection.
=> Practical transfer function measurements were performed.
=> GPIB connectivity was confirmed
External reference test
- External 10MHz reference from an SRS frequency counter was connected to Ext Ref In
=> Ext Ref indicator on the screen appeard
=> The internal oscillator seemed to be locked to the external reference in
Spectrum analyzer test
- Measured the signals from DS345 by R/A/B ch
Sinusoidal signal (1V) swept from 10MHz to 30Mhz
=> Corresponding moving peak was detected in each case
- Noise level measurement
R/A/B channels were terminated. The attenuation at each port was set to 0dB.
Frequency span was changed between 500MHz, 10MHz, 100kHz, 1kHz.
=> Noise level of ~10nV/rtHz between 0.1-500MHz was confirmed. All R/A/B channels have the same performance.
I tested the new table top frequency stabilization system(TTFSS),
I haven’t finished it yet, and accidentally fried one amplifier in the circuit.
We received three sets of a new TTFSS system which will replace the current FSS.
It needs to be checked that the system works as specified before we can use it.
I followed the instruction written on E10000405-v1
The first test inspected how much the currents were drawn from the +/- 24 V power supply.
+24 V drew 350 mA and -24 V drew 160 mA as shown on pwr supply’s current monitor.
They exceeded the specified value which was 200 +/- 20 mA, but nothing went wrong during the test.
Nothing got overheated, all voltage outputs were correct so I proceeded.
I have gone down the list to 6, and everything works as specified.
- Correcting the document for the test procedure
I found a few errors on the instruction document. I’ll notify the author tomorrow.
- How GVA-81 amplifier on D0901894 rev A got fried
During the test, I used a mirror on a stick that looked like a dental tool to see under the board.
Unfortunately, the steel edge touched a board and caused a spark. The voltage on -24 dropped to -16.
I think this happened because the pwr supply tried to decrease the current from shorted circuit,
as I shorted it only short time ( a blink of an eye), it could not reduce the voltage to zero.
When I was checking the power supply and about to adjust the voltage back to the right value
(about 4-5 seconds after the spark,) smoke came out of the circuit.
Koji investigated the circuit and found that a GVA 81 amplifier was broken.
This was checked by applying 5V to the amp, and slightly increasing the current.
The voltage dropped to zero as the amp was broken, so its circuit was shorted.
I’ll see if I can replace this at EE lab at Downs.
If I cannot find a spare one, I’ll replace it with a resistor and resume the test procedure.
Because it amplifies LO signal, which won’t be used during the test.
Since the new generated matrices were created for the measurement made last time, they are of course going to work well for it. We need to test with new independent data to see if it works in general.
After Anchal left for his test, I took the time to set up the iMAC station so that Stephen (and others) can remote desktop into it to use Omnigraffle. For this, I enabled the remote login and remote management settings under "Sharing" in "System Settings". These two should allow authenticated ssh-ing and remote-desktopping respectively. The password is the same that's currently stored in the secrets.
Quickly tested using my laptop (OS:linux, RDP client = remmina + VNC protocol) and it worked. Hopefully Stephen can get it to work too.
Good Enough! Let's move on with output matrix tuning. I will talk to you guys about it privately so that the whole doesn't learn our secret, and highly sought after, actuation balancing.
I suspect that changing the DC alignment of the SUS changes the required input/output matrix (since changes in the magnet position w.r.t. the OSEM head change the sensing cross-coupling and the actuation gain), so we want to make sure wo do all this with the mirror at the correct alignment.
I got some hands-on-experience on using RF photodetectors and the Network Analyzer from Koji. There were newly purchased RF photodetectors from Electro-Optics Technology, Inc.. These were InGaAs Photodetectors with model no.: 120-10050-0001(ET-3010) and 120-10056-0001(ET-3040). The User Guide for the two detectors can be found here. This is the first time we bought the ET-3010 model PD for the 40m lab. It has an operation bandwith >1.5GHz(not tested yet), much higher than other PDs of its kind. This can be used for detecting the output as we 'sweep' the laser frequency for getting data on the optical cavities and the resonating modes inside the cavity. We just tested out the ET-3040 model today but will test out the ET-3010 next week.
Tools and Machines Used:
We worked on the optical bench right in front of the main entrance to the lab. We put the cables, power chords, etc. to their respective places. We used screws, poles, T's, I's, multimeter, Network/Spectrum Analyzer(along with the moving table), a lab computer, Oscilloscope, power supply and the aforementioned PDs for our testing. We took these items from the stack of tools at the Y-arm and the boxes of various different labelled palced near the X-arm. We moved the Network Analyzer(along with the bench) from near the Y-arm to our workplace.
I will include a rough schematic of the setup later.
We alligned the reference PD(High Speed Photoreceiver model 1611) and the test PD(ET-3040 in this case) to get optimal power output. We had set the pump current for the laser at 19.5mA which produced a power of 1.00mW at the output of the fiber couple. At the reference detector the measured voltage was about 1.8V and at the DUT it was about 15mV. The DC transimpedance for the reference detector is 10kOhm and its responsivity to 1064 nm is around 0.75A/W. Using this we calculate the power at the reference detector to be 0.24mW. The DC transimpedance for the DUT is 50Ohm and the responsivity of about 0.9A/W. This amounts to a power of about 0.33mW. After measuring the DC voltages, we connected the laser input to the Network Analyzer and gave in an RF signal with -10dBm and frequency modulation from 100 kHz to 500 MHz. The RF output from the Analyzer is coupled to the Reference Channel(CHR) of the analyzer via a 20dB directional coupler. The AC output of the reference detector is given at Channel A(CHA) and the output from the DUT is given to Channel B(CHB). We got plots of the ratios between the reference detector, DUT and the coupled refernce for the Transfer Function and the Phase. We found that the cut-off frequency for the ET3040 model was at arounf 55 MHz(stated as >50MHz in the data sheet). We have stored the data using the lab PC in the directory .../scripts/general/netgpibdata/data.
The bandwidth of the ET-3040 PD is as stated in the data sheet, >50 MHz.
These PDs have an internal power supply of 3V for ET-3040 and 6V for ET-3010. Do not leave these connected to any instruments after the experiments have been performed or else the batteries will get drained if there is any photocurrent on the PDs.
A similar procedure has to be followed in order to test the ET-3010 PD. I will be doing this tentatively on Monday.
I am adding the text files with the data readings and paramater settings along with the Bode Plot of the data. I plotted these graphs using matplotlib module with python 2.7.
I got some hands-on-experience on using RF photodetectors and the Network Analyzer from Koji. There were newly purchased RF photodetectors from Electro-Optics Technology, Inc.. These were InGaAs Photodetectors with model no.: 120-10050-0001(ET-3010) and 120-10056-0001(ET-3040). The User Guide for the two detectors can be found here. This is the first time we bought the ET-3010 model PD for the 40m lab. It has an operation bandwith >1.5GHz(not tested yet), much higher than other PDs of its kind. This can be used for detecting the output as we 'sweep' the laser frequency for getting data on the optical cavities and the resonating modes inside the cavity. We just tested out the ET-3040 model today but will test out the ET-3010 next week...
Today, I tested the new mini-circuit frequency counter by connecting it with the beat signal output. The frequency counter works fine. Now I am trying to get a display of the frequency in the computer screen using python programming. I have made the code for remotely changing oscilator frequency and it is saved in the folder 'ksnair'. A picture of the new mini circuits frequency counter is attached below. Part no: UFC-6000, S/N: 11501040012, Run: M075270.
Non-testpoint channels seem to be working in data viewer, however testpoints are not. The tpman process is not running on fb40m. My rudimentary attempts to start it have failed.
# /usr/controls/tpman &
# VMIC RFM 5565 (0) found, mapped at 0x2868c90
VMIC RFM 5579 (1) found, mapped at 0x2868c90
Could not open 5565 reflective memory in /dev/daqd-rfm1
16 kHz system
Spawn testpoint manager
no test point service registered
Test point manager startup failed; -1
It looks like it may be an issue with the reflected memory (although the cables are plugged in and I see the correct lights lit on the RFM card in back of fb40m.)
The fact that this is a RFM error is confirmed by /usr/install/rfm2g_solaris/vmipci/sw-rfm2g-abc-005/util/diag/rfm2g_util and entering 3 (which should be the device number).
Interestingly, the device number 4 works, and appears to be the correct RFM network (i.e. changing ETMY lscPos offset changes to the corresponding value in memory).
So, my theory is that when Alex put the cards back in, the device number (PCI slot location?) was changed, and now the tpman code doesn't know where to look for it.
Edit: Doesn't look like PCI slot location is it, given there's 4 slots and its in #3 currently (or 2 I suppose, depending on which way you count). Neither seems much the number 4. So I don't know how that device number gets set.
I haven't done an exhaustive check just yet, but I have loaded a few testpoints in dataviewer, and ran a script that use testpoint channels (specifically the ALS phase tracker UGF setting script), all seems good.
So if I remember correctly, the major CDS fix now required is to solve the model unloading issue.
Thanks to Jamie/Jonathan Hanks/KT for getting us back to this point! Here are the details:
After reading logs and code, it was a simple daqdrc config change.
The daqdrc should read something like this:
configure channels begin end;
What had happened was tpconfig was put before the configure channels
begin end. So when daqd_rcv went to configure its test points it did
not have the channel list configured and could not match test points to
the right model & machine. Dave and I suspect that this is so that it
can do an request directly to the correct front end instead of a general
broadcast to all awgtpman instances.
Simply reordering the config fixes it.
I tested by opening a test point in dataviewer and verifiying that
testpoints had opened/closed by using diag -l. Xmgr/grace didn't seem
to be able to keep up with the test point data over a remote connection.
You can find this in the logs by looking for entries like the following
while the daqd is starting up. When we looked we saw that there was an
entry for every model.
Unable to find GDS node 35 system c1daf in INI fiels
c1iscex did not have test points working last night.
The diag -i command indicated that :
awg 19 0 192.168.113.80 822095891 1 192.168.113.80
awg 45 0 192.168.113.80 822095917 1 192.168.113.80
The first number after the awg should be the DCUID number. The IP address 192.168.113.80 corresponds to c1iscex. So we had awg and testpoints setup for DCUI 19 and 45 on c1iscex. DCUID 19 is c1x01 (the IOP), but 45 was used for a test awhile back.
Turns out that in the testpoint.par file located in /cvs/cds/rtcds/caltech/c1/target/gds/param, there were two entries for c1scx, one with DCUID 24 and also DCUID 45. The model at the time was running with DCUID 24.
So I changed the model DCUID to 45, deleted the [C-node24] entry in the testpoint.par file, and restarted the machine, and also did a "telnet fb 8088" and "shutdown" to restart the frame builder.
As MC2 Trans mon QPD is temporary removed for fixing, we needed a reference for the MC alignment.
I replaced the 10% pick-off in the MCREFL path to the HR mirror.
Now the MCREFL DC with MC unlock is ~2.2, while it is ~0.29 in lock.
i.e. The visibility is 87%.
This means that the MCWFS were disabled for the moment.
On the fb machine in /etc/dis/ there are several configurations files that need to be set for our dolphin network.
First, we modify networkmanager.conf.
We set "-dimensionX 2;" and leave the dimensionY and dimensionZ as 0. If we had 3 machines on a single router, we'd set X to 3, and so forth.
We then modify dishosts.conf.
We add an entry for each machine that looks like:
#Keyword name nodeid adapter link_width
ADAPTER: c1sus_a0 4 0 4
The nodeids (the first number after the name) increment by 4 each time, so c1lsc is:
ADAPTER: c1lsc_a0 8 0 4
The file cluster.conf is automatically updated by the code by parsing the dishosts.conf and networkmanager.conf files.
We uncommented the following lines in the rc.local file in /diskless/root/etc on the fb machine:
# Initialize Dolphin
# Have to set it first to node 4 with dxconfig or dis_nodemgr fails. Unexplai ned.
/opt/DIS/sbin/dxconfig -c 1 -a 0 -slw 4 -n 4
/opt/DIS/sbin/dis_nodemgr -basedir /opt/DIS
For the moment we left the following lines commented out:
# Wait for Dolphin to initialize on all nodes
We were unsure of the effect of the dolphin_wait script on the front ends without Dolphin cards. It looks like the script it calls waits until there are no dead nodes.
In /etc/conf.d/ on the fb machine we modified the local.start file by uncommenting:
This starts the Dolphin network manager on the fb machine. The fb machine is not using a Dolphin connection, but controls the front end Dolphin connections via ethernet.
The Dolphin network manager can be interacted with by using the dxadmin program (located in /opt/DIS/sbin/ on the fb machine). This is a GUI program so use ssh -X when logging into the fb before use.
Each IOP model (c1x02, c1x04) that runs on a machine using the Dolphin RFM cards needs to have the flag pciRfm=1 set in the configuration box (usually located in the upper left of the model in Simulink). Similarly, the models actually making use of the Dolphin connections should have it set as well. Use the PCIE_SignalName parts from IO_PARTS in the CDS_PARTS.mdl file to send and receive communications via the Dolphin RFM.
- The code was modified, compiled, and installed.
- The code is now running. FB was restarted to deal with the change of the channel names.
- Now we have LOCKIN1, 2, and 3. This required the change of the names from C1:LSC-LOCKIN_.... to C1:LSC-LOCKIN1_...
- The LSC screen has also modified. It has three lockins on the screen.
- The corresponding matrix screens have been modified/created and linked from the main screen.
- I need to make the screens more cool but the locking team can start to use those lockins.
As per the request of Anamaria, I have added the slider of the demodulation phase for each RF PD screens.
C1LSC_RFPD.adl screen was modified to have more information.
I forgot to elog that last night I touched up the MC2_TRANS QPD setup. I was perplexed by it always going out of alignment so I investigated.
I found that the fork clamp for the steering mirror for the QPD was not tightened. Shame. The beam diameter was equal to the aperture of the QPD and was clipping. Double shame.
I added a lens and tightened the mounts and centered the beam at ~9 PM yesterday. You can see in the attached trend that the measured power went up by ~10%.
Later, there's a big gap where Valera and Steve change out the PMC. You can see that the MC REFL voltage goes from 4.5 V to 5 V (10% increase in the power delivered to the MC).
There's essentially no change in the total transmission - this indicates that although the PMC transmission is now higher by ~10%, the matching to the IMC has been degraded by an equivalent fraction.
Needs some mode matching work.
The Vac pressure measured at P1 is at 2.5mTorr. I expect we'll hit 3mTorr sometime this afternoon, at which point (according to Steve) the interlock will shut the shutter, and we won't have light in the IFO. Anything which needs to happen with light in the IFO before Monday needs to happen fairly soon.
The PMC is seated on 3 SS balls and it is free to move. I'm sure it will move in an earthquake. Not much, because the input and output K1 mirror frame will act as an earthquake stop.Atm2
Are there a touch of super glue on the balls? No, but there are V grooves at the bottom and on the top of each ball.Atm3
Back in the days when we were talking about getting a new 2W PSL, I was given naming rights by Rana for this new laser.
Today, the 40m PSL was given its new name: Edwin.
Here he is, with his shiny new label:
The pzt driver for PZT1 has been installed.
As there was unknown resistive connection in the vacuum chamber as described below,
the PZT out cable at the PJ driver module should always be disconnected.
The sensor cables have no problem to be connected to the controller.
In fact, they are a good monitor for the state of the PZTs.
In this configuration, Pitch and Yaw direction of PZT1 is under the control of the EPICS value as we expected.
- At the beginning, we tested the PZT driver output with low voltage level (~10V). We did not see any oscillation of the opamps.
The pitch output was observed to be OK, while the YAW output exhibited a half of the expected output voltage.
The opamp was holding correct voltage, however the voltage after the 1K output resister was about a half.
This indicated there was a voltage division happening.
- The cause of the voltage division was tracked. We found that the yaw red (=hot) line is connected to pitch black
in the vacuum chamber with a resistance of 1.4kOhm. The black cables are shorted to the ground level in the PJ driver.
- We decided to unplug the PJ's cable so that we can isolate the black cables while hoping the PZTs were drived only
by the red and white cables. And they did.
- This means that we should not connect the PZT driving cable to the PJ's driver. The sensors have no problem to be connected.
|. o| 5
|o | 17
| o| 4
|o | 16 Yaw Black
| o| 3 Pitch Black
|o | 15 Yaw White
| o| 2 Yaw Red
|o | 14 Pitch White
\ o| 1 Pitch Red
* Pitch White and Yaw White are connected to the ground at the amplifier side.
* Yaw Red and Pitch Black is connected with 1.4kOhm and isolated from the others.
We need a plan for the rest of the week. I want to be closing the heavy doors on Friday at the latest. Please add to / comment on this list!
* Lock MICH to get BS, ITMs aligned well
* Check if beam is hitting center of ITMs.
* Check for clipping around BS
- Use Watek in-vac to look at beam at all 4 BS ports - make sure no clipping going into BS, after BS in the michelson, or the AS port
* Try to get arms to flash??
* Prepare glass beam dumps??
* IPPOS / IPANG - make sure beam gets out of chambers (this may require opening ETMY)
* Jan take photos of ETMX scattering setup
* Manasa take in-vac photos of all tables, for table layouts
* Jan / Manasa viewport transmission
* Install glass beam dumps?
* If ETMY open, install glass baffle
* Check table levelling one last time on all tables.
* Close all heavy doors. (Access connector, ITMX, ITMY, BS, ETMX, ETMY? )
* Drag wipe test masses
* Start at ~10am?
Mon (if not Fri)
* Start pumping
* Jan/Manasa - Measure transmission of viewport at ETMX
We're summarizing the discussions of the last few days as to the game plan for locking.
* Hit center of ETMY, using input optics, PR3.
* Get IPANG out of vac, center QPD.
* AM: Riju do MC mode scans
* Starting right after 40m meeting, if not before: Lock MICH to get BS, ITMs aligned well
* Check if beam is hitting center of ITMX.
- Use Watek to look at beam at all 4 BS ports - make sure no clipping going into BS, after BS in the michelson, or the AS port
- Use some old in-vac mirrors to direct beam out the BS door. Cameras are waiting near BS chamber.
* IPPOS - make sure beam gets out of chamber
* Install glass baffle at ETMY. Jan maybe install baffle at one of ITMs.
THE GOOD: SimPlants ITMX and ETMX are officially ONLINE. Damping has been instituted in both, with varying degrees of success (see Attachment 1). An overview screen for the SimPlants is up (under XARM_Overview in the sitemap - you can ignore the seperate screens for ETMX and ITMX for now, I'll remove them later), C1LSP will be online/functional by Monday.
The super high low-frequency noise in my simPlant is from seismic noise and having a DC response of 1, so that the seismic noise at low frequencies is just passed as is and then amplified along with everything else in the m --> counts conversion. Not quite sure how to deal with this except by NOT having a DC response of 1 (which it technically doesn't have when you do the algebra - Rana said that "it made sense" for the optic to have unity gain at low frequencies, but the behavior is not matching up with reality).
THE BAD: It looks like the ITMX Switch from Reality to simPlant doesn't work (or some of the signals aren't getting switched). When switching from reality to simulation, it looks like the control system is receiving signals from the SimPlant, but is transmitting them to the real thing. As a result, when you flip the switch from reality to sim, ITMX goes seriously crazy and starts slamming back and forth against the stop. REALLY NOT GOOD. As soon as I saw what was going on, I turned back to reality and flipped the watch dogs on (YES THEY WERE OFF). I'll investigate the connections between the plant and control system some more in the morning (i.e. later today) (this is also probably what is causing the "lost connections" in c1sup/sus we can see in the machine status screen).
Problem with ITMX solved! The ITMX block in c1sup hadn't been tagged as "top_names". I rebuilt and installed the model, and there are no longer lost connections, :D
Like a new phoenix, the 40m PSL is in the process of being reborn...
We cleared many old optics and components (including Alberto's favorite periscope) off of the north end of the PSL table. Some optics are stored on the SP table, others on the shelf inside the PSL enclosure.
The new Innolight 2W NPRO is on the table, the PMC has been moved, and the main path of the laser has been sketched out using steering mirrors. Since we still don't have a beam, we're roughly placing all of our optics, and we'll finalize the alignment after turning on the laser.
Using a leveled HeNe, I checked the height of optics we should use to match the height of optics in the chambers by shining the light at the first steering mirror in the chamber, and ensuring that the beam hit the center of that optic . Since the new PSL table height is identical to the AP table, it's not a surprise that from now on we will be using a 4" beam height on the PSL table, rather than the old PSL 3" beam height.
On the to-do list is to make a plate with 4 through holes to raise the PMC up by 1 inch, and to make an adapter plate (or come up with another plan) for mounting the AOM that goes directly after the NPRO/Faraday, among many other things. We also still need to make some space for the RefCav to be put in its new place on the table, and then install it with Steve's help.
In fact, many of the mounts need to be adapted to 4": the beefy steering mirrors going into the PMC, the PMC RFPD, the ISS AOM, the Faraday between the NPRO and the AOM, the NPRO itself, the ISS PDs.
Also for the FSS: the 21.5 MHz EOM, the PBS, the AOM, the refcav periscope, and the RFPD.
Its obvious, in retrospect, that we would have to do this, but it somehow didn't occur to me until actually trying to put things on the table...
The NPRO itself is already tapped with 3 (metric) M3 holes. It also has 4 (un-tapped) holes at its 4 corners which look like they are for feet. Anyone have a mount design for the Innolight NPRO already?
We also started labeling the table with the new coordinate system. In this system, the NE corner is the origin. The screw hole which is most NE is 1,1. The numbering increases in the south (+X) direction and goes negative in the west (-Y) direction.
Joon Ho and I took a look at the RF stuff that Alberto left, and we determined that we've got most everything that we need. On Monday, Joon Ho will list off the stuff that we're missing, and we'll have Steve order it.
Joon Ho also replaced the temporary front panel to the RF generation box with Alberto's fancy new panel. Pics are here (although you have to sign in as foteee to see them).
Work on the frequency distribution box will continue on Monday.
(Jon, Keerthana, Sandrine)
We tried to align the AUX and PSL laser yesterday. We collected the data from the spectrum analyser for the Y-ARM reflection and also for the Y-ARM transmission from the ETM mirror. I am attaching the plots here.
... not just because we haven't locked the interferometer for quite some time. I mean, it literally stinks. The chiller's chiller is molding. Its' dripping water and there's mold all under it (Jo just confirmed: "yeah, it's mold").
Someone from Caltech maintenance just crossed the door. Hopefully he'll help us fix it.
I'll keep you updated. Stay tuned.
[Koji and Kiwamu]
We obtained two dark port beams on the AP table: OMC REFL and AS
- First, IPANG and BS were aligned so as to have the beams on the center of the ETMs.
- Then ITMX/ITMY/PRM/SRM were aligned to have fringes in a single spot anywhere.
- As we already had the dark port beam on the steering mirrors on the BS table, today the PZT mirrors were adjusted.
This work was the beam steering between the BS table to the OMC table. After some tweaking of the mirror mounts,
the spot on the last PZT mirror was found.
As we have not touched any of the OMC optics since they were aligned well, the alignment has been adjusted by the nobs of the PZT steering mirrors.
Once the beam is on the output mode matching telescope (OMMT), the work was quite easy thanks to the beam shrinking by the OMMT.
Note that the dark port beam is slightly clipped by the green steering mirror. The steering mirror will be moved next time.
After the alignment, we indeed obtained OMC REFL and AS beams on the AP table.
The fringes were visible on the OMC REFL CCD.
We keep the dark port setup on the OMC (in-vac) and AP tables so that they can be the reference of the dark port alignment.
In principle we can align the beams onto the OMC by the two PZT mirrors.
What is left?
Our minimum success of this vent is to setup the X arm cavity which is needed for the green locking.
This setup was already realized. So we fulfilled the condition to close the tank even if the damping of
the ETMY is not achieved. (But we should try)
Tomorrow, we make a light touches to POY, Green, IPPOS, and check the table leveling, clamping, etc, in general.
JD: We should check OSEMs for all optics *after* table leveling. Some of them (esp. BS and ITMX) are currently close to their limits right now.
KA: Check green alignment. / Take photos of the tables. / Fix the leveling weights
Location Optics Action
@ITMY - POY mirror replacement (45deg->0deg) / alignment
@BSC - Green steering alignment
IPPOS steering alignment
@ETMX - Al foil removal
@ETMY - ETMY damping
@ITM/ETM - Mirror Wiping
We have Completed the hardware changes to the full set of 8 demod boards. The last one completed today is AS11. I have collected the info on all the demod boards available so far in the table below. As we measure the actual phase and amplitude unbalance we will expand this table to include new info.
In order to see the acoustic coupling on arm signals, I set 6 microphones and the speaker on the AP table. The microphones are not seismically isolated for now.
I have a signal generator under the AP table.
When I played the 43 Hz triangular wave sound, I could see some coherence between POY error signal and microphones even though there is no peak in POY.
Don't try to re-invent the mic mount: just copy the LIGO mic mount for the first version.
This is how to post PDF:
From DTT, print the plot as a postscript file.
Then use ps2pdf to make a archival PDF version (the flag is the key!). Example:
ps2pdf -dPDFX /home/controls/Desktop/darm.ps
Shown below are the plots of the amplitude and phase of the Mephisto laser light modulated with a chopper as a square wave at about 1 kHz. The color bar for the phase should run from -pi to pi, and it does when I don't accidently comment out the color bar function. Anyway, the phase is consistently pi/4 or pi/4 plus or minus pi. Usually all three of these phases occur within the same image, as shown below. Also, the amplitude is a factor of two or so higher than it should be where this phase jump occurs. I think these problems are associated with the nature of the square wave. However, there is a software bug that appears to be independent of the input data: there is a rounding error that causes the amplitude to jump to infinity at certain points. This happened for only a dozen or so pixels so I deleted them from the amplitude plot shown below. I am currently working on a more robust code that will use the Newton-Raphson method for nonlinear systems of equations.
i just heard a rather large exploding sound in the control room.
I tried to locate the source and found the projector is not illuminating the wall anymore.
There is a slight smell of burning, but nothing is smoking.
Probably the lamp ended its life.
Rana and I just talked about the projector life time an hour ago! It must have been hearing!
i just heard a rather large exploding sound in the control room.
I tried to locate the source and found the projector is not illuminating the wall anymore.
There is a slight smell of burning, but nothing is smoking.
We should try purchase a projector with LED this time...longer lifetime! I guess the price of replacing the lamp in the one we have will be more or less same as a new one!