 Wed Jun 6 14:36:15 2018, gautam, Update, LSC, TRX clipping
|
For some time now, I've been puzzled by the unreliability of the ASS_X dither alignment servo. Leaving the servo on, TRX often begins to decay to
a lower value, and even after freezing the dither at the maximum TRX values, I can manually align the mirrors to increase TRX. We have suspected some kind
of clipping in the TRX path that is responsible for this behaviour. Today I decided to investigate this a bit further. To have the arm locked and to inspect |
Wed Jun 6 14:50:25 2018, gautam, Update, General, LSC triggering 
|
I though that the "C1LSC_TRIG_MTRX" MEDM screen completely controls the triggring of LSC signals. But today while trying to trigger the X-arm
locking servo on AS110 instead of TRX, I found some strange behaviour. Summary of important points:
Even though the servo was supposed to be triggered on AS110, the act of me blocking the beam on the EX table destroyed the lock. I verified |
 Wed Jun 6 15:12:29 2018, Kira, Update, PEM, parts from lab
|
Got this 1U box from the Y arm that we could potentially use (attachment 1). It doesn't have handles on the front but I guess we could attach them
if necessary. Attachment 2 is a switch that could be used instead of a light up switch, but now we need to add LEDs on the front panel that indicate that
the switch is functional. Attachment 3 is a terminal block that we can use to attach the 16 gage wire to since it is thick and attaching it directly to |
|
Thu Jun 7 10:26:36 2018, keerthana, Update, PSL, observing the resonance signal corresponding to the injected frequency.
|
(Johannes, Koji, Keerthana)
The PLL loop ensures that the frequency difference between the PSL laser and the AUX laser is equal to the frequency we provide to the Local
Oscillator (LO) with the help of a Marconi. Only a small pick off part of both the AUX and PSL lasers are going to the PLL loop. The other part of both |
|
Thu Jun 7 12:20:53 2018, gautam, Update, CDS, slow machine bootfest
|
| FSS slow wasn't running so PSL PZT voltage was swinging around a lot. Reason was that was c1psl unresponsive. I keyed the crate, now it's okay. Now ITMX is stuck - Johannes just told be about an un-elogged |
|
Thu Jun 7 14:35:26 2018, keerthana, Update, elog, Table- useful for doing the scanning.
|
I think this table will help us to fix the scanning range of the Marconi frequency. This will also help in predicting the position of the resonance peak
corresponding to the injected frequency.
fdiff = fm ±80 |
|
Thu Jun 7 16:15:03 2018, gautam, Update, LSC, TRX clipping
|
I opted for the quickest fix - I raised the height of the offending steering mirror using a 0.25" shim. In the long term, we can get a taller post
machined. After raising the mirror height, I then checked the DC centering of the spot on the DC PD using a scope.
Looking at the performance of the X arm ASS, I no longer see the strange oscillatory behaviour I described in my previous post |
|
Thu Jun 7 20:19:53 2018, pooja, Update, ,
|
| Just to inform, I'm working in optimus to develop python code to train the neural network since it requires a lot of memory. |
|
Thu Jun 7 20:21:15 2018, Koji, Update, Computer Scripts / Programs, /cvs/cds Backup in danger
|
Local backup on chiara
seems not working since Nov 19, 2017.
/opt/rtcds/caltech/c1/scripts/backup/localbackup.log |
|
Thu Jun 7 22:36:09 2018, not keerthana, Update, PSL, observing the resonance signal corresponding to the injected frequency.
|
| I worked a bit on the PSL table today |
|
Fri Jun 8 00:36:54 2018, gautam, Update, PSL, observing the resonance signal corresponding to the injected frequency.
|
It isn't clear to me in the drawing where the Agilent is during this measurement. Over 40m of cabling, the loss of
signal can be a few dB, and considering we don't have a whole lot of signal in the first place, it may be better to send the stronger RF
signal (i.e. Marconi pickoff) over the long cable rather than the weak beat signal from the Transmission photodiode. |
|
Fri Jun 8 01:08:22 2018, johannes, Update, PSL, First light of AUX at YEND
|
Among the things that we hadn't taken care of yesterday before beginning to look for transmission signals were the polarization of the AUX beam on
the AS table and optimizing the PLL feedback. The AUX beam is s-polarized on the PSL table (choice due to availablility of mirrors), and I added a half
waveplate in front of the fiber to match it's axes. I placed another half-waveplate at the fiber output and send the reflection port of a PBS cube |
|
Fri Jun 8 01:58:56 2018, gautam, Update, LSC, DRMI locking attempt again
|
Given the various changes to the IFO config since last Thursday when I was last able to lock the DRMI, I wanted to try once again tonight. However, I
had no success. By my judgement, the alignment is fine as judged by looking at mode flashes on the cameras. However, despite following the usual alignment
procedures, I did not get a single lock in tonight. |
|
Fri Jun 8 14:40:55 2018, c1lsc, Update, CDS, i am dead
|
| |
|
Fri Jun 8 20:15:08 2018, gautam, Update, CDS, Reboot script
|
Unfortunately, this has happened (and seems like it will happen) enough times that I set up a script for rebooting the machine in a controlled way, hopefully
it will negate the need to repeatedly go into the VEA and hard-reboot the machines. Script lives at /opt/rtcds/caltech/c1/scripts/cds/rebootC1LSC.sh. SVN committed. |
|
Sun Jun 10 03:46:38 2018, Koji, Update, IOO, WFS HEAD SW confusion
|
I was checking on the slow machine channels and found something I could not understand.
On the IOO WFS HEAD screen, there are two sets of 4 switches (magenta rectangles in Attachment 1) labeled 2/4/8/16dB.
But as far as I could confirm with the WFS demod (D980233) and WFS head (D980012) drawings, they are the gain |
|
Sun Jun 10 15:04:33 2018, pooja, Update, Cameras, Developing neural network
|
Aim: To develop a neural network in order to correlate the intensity fluctuations in the scattered light to the angular motion of the test mass. A block
diagram of the technique employed is given in Attachment 1.
I have used Keras to implement supervised learning using neural network (NN). Initially I had developed a python code that converts a video (59 |
|
Mon Jun 11 11:45:13 2018, keerthana , Update, elog, Comparison of the analytical and finesse values of TMS and FSR.
|
Quantity
Analytical Value
Finesse Value
Percentage
Error
Free Spectral range (FSR)
3.893408 MHz
|
|
Mon Jun 11 13:55:33 2018, keerthana, Update, General, Project Updates
|
As of now, I have made the codes needed to sweep the marconi frequency for taking the cavity scan data, the photo diode at the y-end is conected to the
spectrum analyser already and I also have the finesse simulation of the Ideal Fabry-perot cavity. By seeing my last elog entry, Gautam suggested me that
I need to take a different approach for estimating the FSR and TMS value from the Finesse graph. That is, by using least square fit models. Now I am trying |
|
Mon Jun 11 17:18:39 2018, pooja, Update, Cameras, CCD calibration
|
Aim: To calibrate CCD of GigE using LED1050E.
The following table shows some of the specifications for LED1050E as given in Thorlabs datasheet.
Specifications
|
|
Mon Jun 11 18:10:51 2018, Koji , Update, elog, Comparison of the analytical and finesse values of TMS and FSR.
|
Hmm? What is the definition of the percentage error? I don't obtain these numbers from the given values.
And how was the finesse value obtained from the simulation result? Then what is the frequency resolution used in Finesse simulation? |
|
Mon Jun 11 18:49:06 2018, gautam, Update, CDS, c1lsc dead again
|
Why is this happening so frequently now? Last few lines of error log:
[
575.099793] c1oaf: DAQ EPICS: Int = 199 Flt = 706 Filters = 9878 Total = 10783 Fast = 113 |
|
Mon Jun 11 19:16:49 2018, keerthana, Update, elog, Comparison of the analytical and finesse values of TMS and FSR.
|
The percentage error which I found out =[(analytical value - finesse value)/analytical value]*100
But inorder to find the finesse value, I just used curser to get the central frequency of each peak and by substracting one from the other I
found TMS and FSR. |
|
Mon Jun 11 22:05:03 2018, Koji, Update, elog, Comparison of the analytical and finesse values of TMS and FSR.
|
> The percentage error which I found out =[(analytical value - finesse value)/analytical value]*100
Yes, I this does not give us 0.70%
(3.893408 - 3.8863685)/3.893408 *100 = 0.18% |
|
Mon Jun 11 22:18:18 2018, keerthana, Update, elog, Comparison of the analytical and finesse values of TMS and FSR.
|
Oopss !! I made a mistake while taking the values from my notes. Sorry.
Quote:
> The percentage error which I found out =[(analytical value - finesse value)/analytical value]*100 |
|
Mon Jun 11 22:46:24 2018, Koji, Update, IOO, WFS HEAD SW confusion
|
The unfortunate discovery today was that the attenuator switches on the IMC WFS heads are actually assigned to individual segments, and they are active.
That means that we have been running the WFS with an uneven gain setting. The attached PDFs show that the signals with the attenuators on and off all at
the same time, while the WFS servo output was frozen. A more annoying feature is that when some of the attenuators are on, this does not lower the |
|
Mon Jun 11 23:22:53 2018, gautam, Update, CDS, EX wiring confusion
|
[Koji, gautam]
Per this elog, we don't need any AIOut channels or Oplev channels. However, the
latest wiring diagram I can find for the EX Acromag situation suggests that these channels are hooked up (physically). If this is true, there are 12 ADC |
|
Tue Jun 12 03:22:25 2018, gautam, Update, LSC, AUX laser shuttered
|
I worked a bit on recovering the DRMI locking again tonight. I decided to shutter the AUX laser on the PSL table at least until I figured out the correct
locking settings. As has become customary now, there was a cable in the AS beampath (leading from the AS55 DC monitor to nothing, through the enclosure
side panel, it is visible in Attachment #3 in this elog) which I only found after 30mins of |
|
Tue Jun 12 19:27:25 2018, pooja, Update, Cameras, CCD calibration
|
Today I made the led (1050nm) circuit inside a box as given in my previous elog. Steve drilled a 1mm hole in the box as an aperture for led light.
Resistance (R) used = 665 .
We connected a power supply and IR has been detected using the card. |
|
Wed Jun 13 01:02:40 2018, gautam, Update, LSC, Reliable and repeatable 1f DRMI locking
|
[koji, gautam]
With Koji's help, I got repeatable and reliable DRMI locking going again tonight - this is with the AS path optics for the spectroscopy measurement
in place, although the AUX laser remained shuttered tonight. Results + spectra tomorrow, but here's what I did: |
|
Wed Jun 13 11:17:40 2018, gautam, Update, LSC, PRCL loop shape anomaly
|
Attachment #1 shows the measured PRCL
loop shape. The blue line is meant to be the "expected" loop shape. While the measured loop shape tracks the expectation down to ~100 Hz, I cannot
explain the shape below it. I am also not sure what to make of the fact that there is high coherence down to 10 Hz fron IN2 to IN1, but no coherence between |
|
Wed Jun 13 11:59:03 2018, keerthana, Update, elog, command line enabled code for frequency scanning
|
I have modified the code for frequency scanning and have made it completely command line enabled. The code is written in python. It is saved in the name
"frequency_scanning_argparse.py". I have uploaded it to the Mode-Spectroscopy Github repository.
Inorder to use this code there are two ways. |
|
Wed Jun 13 12:21:09 2018, gautam, Update, ALS, PDFR laser checkout
|
I want to use the Fiber Coupled laser from the PDFR system to characterize the response of the fiber
coupled PDs we use in the BeatMouth.
The documentation is pretty good: for a first test, I did the following in this order: |
|
Wed Jun 13 18:08:36 2018, keerthana, Update, , Finesse code for cavity scan
|
The unit mentioned in the x-axis was wrong. So I have remade the graphs. The point where frequency equals to zero is actually the frequency corresponding
to the laser, which is in the range of 1014 Hz and it caliberated as zero.
Quote:
|
|
Wed Jun 13 22:07:31 2018, gautam, Update, ALS, BeatMouth PDFR measurement
|
Summary:
Neither of the Menlo
FPD310 fiber coupled PDs in the beat mouth have an optoelectronic response (V/W) as advertised. This possibly indicates a damaged RF amplification |
|
Wed Jun 13 23:23:44 2018, johannes, Update, CDS, EX wiring confusion
|
It's true.
I went through the wiring of the c1auxex crate today to disentangle the pin assignments. The full detail can be found in attachment #1, #2 has
less detail but is more eye candy. The red flagged channels are now marked for removal at the next opportunity. This will free up DAQ channels as follows: |
|
Thu Jun 14 00:40:42 2018, gautam, Update, LSC, PRCL loop shape anomaly
|
don't use IN_1/IN_2: recall pizza meeting from a few weeks back: use IN1/EXC + Al-Gebra
Quote:
|
|
Thu Jun 14 00:46:09 2018, rana, Update, IOO, WFS HEAD SW confusion
|
its painful, but you and I should probably take these out, bypass the switches and use them with fixed gain; the 'Reed
Relay' attenuators are not a good part for this app.
The historical problem is that they tend to self oscillate with full gain because they had 2 MAX4106 in series which couple to each other in |
|
Thu Jun 14 10:41:00 2018, gautam, Update, CDS, EX wiring confusion
|
Do we really have 2 free ADC channels at EX now? I was under the impression we had ZERO free, which is why we wanted to put a new ADC unit in. I think
in the wiring diagram, the Vacuum gauge monitor channel, Seis Can Temp Sensor monitor, and Seis Can Heater channels are missing. It would also be good
to have, in the wiring diagram, a mapping of which signals go to which I/O ports (Dsub, front panel BNC etc) on the 4U(?) box housing all the Acromags, |
|
Thu Jun 14 13:29:51 2018, gautam, Update, General, PSL shutter closed, all optics misaligned
|
[jon, gautam]
Jon is doing some characterization of the AUX laser setup for which he wanted only the prompt retroreflection from the SRM on the AS table, so
the PSL shutter is closed, and both ITMs and ETMs are misaligned. The prompt reflection from the SRM was getting clipped on something in vacuum - the ingoing |
|
Thu Jun 14 15:21:58 2018, gautam, Update, Computer Scripts / Programs, /cvs/cds Backup in danger
|
I think this is because /cvs/cds is getting too big. lsblk reveals:
controls@chiara|~>
lsblk |
|
Thu Jun 14 15:24:32 2018, Steve, Update, PEM, ADC DAC In Line Test Boards are in
|
We have 6 of these boards now in cabinet E7
Quote:
I wired all 32 channels going to the AA board directly to the ADC as described in the previous |
|
Thu Jun 14 15:31:18 2018, johannes, Update, CDS, EX wiring confusion
|
Bad wording, sorry. Should have been channels in excess of ETMX controls. I'll add the others to the list as well.
Updated channel list and wiring diagram attached. Labels are 'F' for 'Front' and 'R' for - you guessed it - 'Rear',
the number identifies the slot panel the breakout is attached to. |
|
Thu Jun 14 18:09:24 2018, gautam, Update, LSC, Reliable and repeatable 1f DRMI locking
|
I finally analyzed the sensing measurement I ran on Tuesday evening. Sensing responses for the DRMI DOFs seems consistent with what I measured in October 2017, although the relative phasing of the DoFs in the sensing PDs has changed significantly.
For what it's worth, my Finesse simulation is here. |
|
Thu Jun 14 19:30:12 2018, gautam, Update, General, IFO alignment restored
|
| All optics have been re-aligned. Jon/Johannes will elog about the work today. |
|
Thu Jun 14 22:45:05 2018, johannes, Update, General, AUX beam SRC alignment
|
[Jon, Gautam, Johannes]
Jon spent some time trying to align the AUX beam to the SRC today, I got to the game kind of late so maybe others can add more detail.
The AUX beam that is reflected by the SRM looks terribly misshapen - it is quite elongated in vertical direction. Unfortunately I didn't |
|
Fri Jun 15 00:53:21 2018, gautam, Update, LSC, Calibrated MICH spectrum
|
Using the numbers from the sensing measurement, I calibrated the measured in-loop MICH spectrum from Tuesday night into free-running displacement noise.
For convenience, I used the noise-budgeting utilities to make this plot, but I omitted all the technical noise curves as the coupling has probably changed
and I did not measure these. The overall noise seems ~x3 higher everywhere from the best |
|
Fri Jun 15 09:14:42 2018, Steve, Update, General, Oplev sums
|
Oplev sums of 240 days.
Quote:
Since there have been various software/hardware activity going on (stack weighing, AUX laser PLL, computing timing |
|
Fri Jun 15 09:51:55 2018, pooja, Update, Cameras, Developing neural network
|
Aim : To develop a neural network on simulated data.
I developed a python code that generates a 64*64 image of a white Gaussian beam spot at the centre of black background. I gave a sine wave of
frequency 0.2Hz that moves the spot vertically (i.e. in pitch). Then I simulated this video at 10 frames/sec for 10 seconds. Then I saved this data into |
|
Fri Jun 15 14:22:05 2018, gautam, Update, ALS, BeatMouth PDFR measurement
|
I did the measurement with the BeatMouth open today. Main changes:
Directly pipe the RF output of the Menlo PDs to the Agilent, bypassing the 20dB coupler inside the BeatMouth.
Directly pipe
the unused port of the Fiber Beamsplitter used to send light to the Menlo PD to an in-air collimator, which then sends the beam to the NF1611 reference |