>> which decimate
if (`pgrep lockMZ | wc -l` > 1) then
echo lockMZ is already running!
pgrep `basename $0` | grep -v $$ > /dev/null
echo Another copy of this program is already running. Exiting!
I installed svn on op440m. This involved installing the following packages from sunfreeware:
apache-2.2.6-sol9-sparc-local libiconv-1.11-sol9-sparc-local subversion-1.4.5-sol9-sparc-local
db-4.2.52.NC-sol9-sparc-local libxml2-2.6.31-sol9-sparc-local swig-1.3.29-sol9-sparc-local
expat-2.0.1-sol9-sparc-local neon-0.25.5-sol9-sparc-local zlib-1.2.3-sol9-sparc-local
The packages are located in /cvs/cds/caltech/apps/solaris/packages. The command line to install
a package is "pkgadd -d " followed by the package name. This can be repeated on nodus to get
svn over there. (Kind of egregious to require an apache installation for the svn _client_, I
Phil Ehrens gave me a DVD of the 40m elog, apache, and (Jamie's) SVN archive.
I copied it to nodus:/home/controls/dvd-from-ehrens. Once we get the elog
running on nodus, we can copy the datafile over again from dziban (so that
we don't lose any elog entries) and switch over.
I was able to check out the 40m SVN here in Livingston using this command:
svn co svn+ssh://email@example.com/cvs/cds/caltech/svn/trunk/medm
As you might guess, this uses ssh in place of the web server (which we don't have yet).
3 fsr = 33 195 439 Hz
12 fsr = 132 781 756 Hz
15 fsr = 165 977 195 Hz
18 fsr = 199 172 634 Hz
I mounted the optoisolator on the DIN rail and connected the 3 first channels
to the optoisolator inputs 1,3,4 respectively. I connected the +15V input voltage into the input(+) of the optoisolator.
The outputs were connected to DB9F-2 where those channels were connected before.
I added DB9F-1 to the front panel to accept channels from the RTS. I connected the fast channels to connectors 1,2,3 from DB9F-1 to DB9F-2 according to the wiring diagram. The GND from DB9F-1 was connected to both connector 5 of DB9F-2 and the output (-).
I tested the channels: I connected a DB9 breakout board to DB9F-2. I measured the resistance between the RTS GND and the isolated channels while switching them on and off. In the beginning, when I turned on the binary channels the resistance was behaving weird - oscillating between low resistance and open circuit. I pulled up the channels through a 100Kohm resistor to observe whether the voltage behavior is reasonable or not. Indeed I observed that in the LOW state the voltage between the isolated channel and slow GND is 15V and 0.03V in the HIGH state. Then I disconnected the pull up from the channels and measured the resistance again. It showed ~ stable 170ohm in the HIGH state and an open circuit in the LOW state. I was not able to reproduce the weird initial behavior. Maybe the optoisolator needs some warmup of some sort.
We still need to wire the rest of the fast channels to DBF9-3 and isolate the channels in DBF9-4. For that, we need another optoisolator.
There is still an open issue with the BI channels not read by EPICS. They can still be read by the Windows machine though.
Alex wrote a new code to implement LSP noise generator. The code is based on 64 bit random number generator from Numerical Recipes 3rd ed ch 7.1 (p 343).
Joe made two instances in the LSP model.
The attached plot shows the spectra and coherence of two generators. The incoherence is ~1/Navg - statistically consistent with no coherence.
I put matlab files and a summary into the 40m wiki for the fitting of the 40m Optickle transfer functions and generating digital filters for the simulated plant:
The filters are not loaded yet. Joe and Alex will make a rcg code to make a matrix of filters (currently 5x15=75 elements) which will enable the simulated plant tf's.
Joe and I tried to put a signal through the DARM loop but the signal was not going through the memory location in the scx part of the simulated plant.
Edit by Joe:
I was able to track it down to the spx model not running properly. It needed the Burt Restore flag set to 1. I hadn't done that since the last rebuild, so it wasn't actually calculating anything until I flipped that flag. The data is now circulating all the way around. If I turn on the final input (the same one with the initial 1.0 offset), the data circulates completely around and starts integrating up. So the loop has been closed, just without all the correct filters in.
It appears that foton does not like the unstable poles, which we need to model the transfer functions.
But one can try to load the filters into the front end by generating the filter file e.g.:
# MODULES DARM_ASDC
### DARM_ASDC ###
# SAMPLING DARM_ASDC 16384
# DESIGN DARM_ASDC
DARM_ASDC 0 21 6 0 0 darm 1014223594.005454063416 -1.95554205062071 0.94952075557861 0.06176931505784 -0.93823068494216
-2.05077577179611 1.05077843532639 -2.05854170261687 1.05854477394411
-1.85353637553024 0.86042048250739 -1.99996540107622 0.99996542454814
-1.93464836371852 0.94008893626414 -1.89722830906561 0.90024221050918
-2.04422931770060 1.04652211283968 -2.01120153956052 1.01152717233685
-1.99996545575365 0.99996548582538 -1.99996545573320 0.99996548582538
Unfortunately if you open and later save this file with foton it will strip the lhp poles.
In my calculation of the digital filters of the optical transfer functions the carrier light is resonant in coupled cavities and the sidebands are resonant in recycling cavities (provided that macroscopic lengths are chosen correctly which I assumed).
- The PMC REFL PD was moved from the temporary location to the one called for by the PSL layout (picture attached). The leakage beams were dumped.
- The FSS reference cavity was aligned using temporary periscope and scanned using NPRO temperature sweep. The amplitude of the sweep (sine wave 0.03 Hz) was set such that the PMC control voltage was going about 100 V p-p with. With rough alignment the visibility was as high as 50% - it will be better when the cavity is locked and better aligned but not better than 80% expected from the mode astigmatism that Tara and I measured on Thursday. The astigmatism appear to come from the FSS AOM as it depends on the AOM drive. We reduced the drive control voltage from 5 V to 4V beyond that the diffraction efficiency went below 50%. The FSS REFL PD was set up for this measurement as shown in the attached picture. There is also a camera in transmission not shown in the picture.
Kiwamu and I found that the first lens in the PMC mode matching telescope was mislabeled. It is supposed to be PLCX-25.4-77.3-C and was labeled as such but in fact it was PLCX-25.4-103.0-C. This is why the PMC mode matching was bad. We swapped the lens for the correct one and got the PMC visibility of 82%. The attached plot shows the beam scans before and after the PMC. The data were taken with the wrong lens. The ABCD model shown in the plot uses the lens that was there at the time - PLCX-25.4-103.0-C. The model for the PMC is just the waist of 0.371 mm at the nominal location. The snap shot of the ABCD file is attached. The calculation includes the KTP for FI and LiNb for EOM with 4 cm length. The distances are as measured on the table.
The attached plot shows the beam scans of the beam leaking from the back mirror of the PMC to the BS cube that first turns the S-pol beam 90 deg to the AOM and then transmits the AOM double passed and polarization rotated P-pol beam to the reference cavity. The beam from the PMC is mode matched to the AOM using a single lens f=229 mm. The ABCD file is attached. The data were taken with VCO control voltage at 5 V. We then reduced the voltage to 4 V to reduce the astigmatism. Tara has the data for the beam scan in this configuration in his notebook.
The beam from AOM is mode matched to the reference cavity using a single lens f=286.5 mm. The ABCD file is attached.
The RefCav is locked and aligned. I changed the fast gain sign by changing the jumper setting on the TTFSS board. The RefCav visibility is 70%. The FSS loop ugf is about 80 kHz (plot attached. there is 10 dB gain in the test point path. this is why the ugf is at 10 dB when measured using in1 and in2 spigots on the front of the board.) with FSS common gain max out at 30 dB. There is about 250 mW coming out of the laser and 1 mW going to RefCav out of the back of the PMC. So the ugf can be made higher at full power. I have not made any changes to account for the PMC pole (the FSS is after the PMC now). The FSS fast gain was also maxed out at 30 dB to account for the factor of 5 smaller PZT actuation coefficient - it used to be 16 dB according to the (previous) snap shot. The RefCav TRANS PD and camera are aligned. I tuned up the phase of the error signal by putting cables in the LO and PD paths. The maximum response of the mixer output to the fast actuator sweep of the fringe was with about 2 feet of extra cable in the PD leg.
I am leaving the FSS unlocked for the night in case it will start oscillating as the phase margin is not good at this ugf.
- NPRO injection current 1.0 A
- PMC losses ~32%
- FSS AOM diffraction efficiency ~52%
The attached plots show the PMC cavity line width measurement with 1 mW and 160 mW into the PMC. The two curves on each plot are the PMC transmitted power and the ramp of the fast input of the NPRO. The two measurements are consistent within errors - a few %. The PMC line width 3.5 ms (FWHM) x 4 V / 20 ms (slope of the ramp) x 1.1 MHz / V (NPRO fast actuator calibration from Innolight spec sheet) = 0.77 MHz.
Here is the output of the calculation using Malik Rakhmanov code:
modematching = 8.4121e-01
transmission1 = 2.4341e-03
transmission2 = 2.4341e-03
transmission3 = 5.1280e-05
averageLosses = 6.1963e-04
visibility = 7.7439e-01
fw = 0.77e6; % width of resonance (FWHM) in Hz
Plas = 0.164; % power into the PMC in W
% the following number refer to the in-lock cavity state
Pref = 0.037; % reflected power in W
Ptr = 0.0712; % transmitted power in W
Pleak = 0.0015; % power leaking from back of PMC in W
The PMC mode matching was initially done at low power ~150 mW. It was expected and found that at full power ~2 W (injection current 2.1 A) the mode matching got much worse:
the visibility degraded from 80% to 50% (1 - refl locked/refl unlocked) . The thermal lensing could be in the laser, EOM, or FI.
The first attached plot shows the scan of the beam after the EOM at low and full laser power. At full power the waist position is 10 mm after the turning mirror after the EOM and the waist size is 310 um.
The second plot shows the ABCD calculation for the mode matching solution.
I removed the MM lens PLCX-25.4-77.3-C and placed the PLCX-25.4-180.3-UV about 20 mm after the first PMC periscope mirror (the second mirror after the EOM).
The PMC visibility improved to 94% and the power through the PMC, as measured by the PMC transmission PD, went up by a factor of 2.
Now that we have increased the range of the AA to +/- 10 V I have increased the PRM side OSEM transimpedance from 29 kV/A to 161 kV/A by changing the R64 in the satellite box. The first attached plot shows the ADC input spectrum before and after the change with analog whitening turned off. The PD voltage readback went up from 0.75 to 4.2 V. The second attached plot shows the sensor, ADC, and projected shot noise with analog whitening turned on and compensated digitally. The ADC calibration is 20 V/ 32768 cts. The PRM damping loops are currently disabled.
I checked for oscillation by looking at the monitor point at the whitening board. There was no obvious oscillation on a scope - the signal was 20 mV p-p on 1 us scale which was very similar to the LL channel.
We missed a factor of 2 in the ADC calibration: the differential 16 bit ADC with +/-10 V input has 20 V per 32768 counts (1 bit is for the sign). I confirmed this calibration by directly measuring ADC counts per V.
So the ADC input voltage noise with +/-10V range around 100 Hz is 6.5e-3 cts/rtHz x 20V/32768cts = 4.0 uV/rtHz. Bummer.
The ADC quantization noise limit is 1/sqrt(12 fs/2)=1.6e-3 cts/rtHz. Where the ADC internal sampling frequency is fs=64 kHz. If this would be the limiting digitization noise source then the equivalent ADC input voltage noise would be 1 uV/rtHz with +/-10 V range.
I measured the SRM OSEM (no magnets at the moment) noise out of the satellite box with a SRS785 spectrum analyzer. I inserted a break out board into the cable going from the satellite box to the whitening board. The transimpedances of the SRM OSEMs are still 29.2 kOhm. The DC voltages out of the SRM satellite box are about 1.7 V. The signal was AC coupled using SR560 with two poles at 0.03 Hz and a gain of 10.
The noise is consistent with the one measured by the ADC except for the 3 Hz peak which does not show up in the ADC spectrum from Sunday. The peak appears in several channels I looked at. The instrument noise floor was measured by terminating the SR560 with 50 Ohm.
I recommend to change all OSEM transimpedance gains from 29 to 161 kV/A. Beyond this gain one will rail the AA filter module when the magnet is fully out of the OSEM.
The OSEM noise at 1 Hz is about factor of 10 above the shot noise. The damping loops impress this noise on the optics around the pendulum resonance frequency. Also the total contribution to the MC cavity length is sqrt(12) time the single sensor as there are 12 OSEMs contributing to MC length. The ADC noise is currently close but never the less not limiting the OSEM noise below 100 Hz. It can be further reduced by getting an extra factor of 2-3 in whitening gain above ~0.3 Hz. The rms of the ADC input of the modified PRM SD (R64 = 161 kOhm) channel is 10-20 cts during the day with damping loop off and whitening on.
The transimpedance amplifier LT1125CS is also not supposed to be limiting the noise. At 1 Hz the 1/f part of the noise: In<1pA/rtHz and Vn<20nV/rtHz.