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ID Date Author Type Categoryup Subject
  1026   Fri Jul 20 00:47:10 2012 taraNotesEnvironmentthe wall is plastered

The wall between PSL and ATF was drilled, chiseled and plastered. This hole is for laser distribution via optical fiber. I'll contact the carpenter shop to have cable tray installed in PSL and ATF soon.




The cable tray will run along the wall, some of the cable rack will be lowered for a few inches.

  1035   Tue Aug 7 23:30:19 2012 ranaSummaryEnvironmentEQ

Just felt an EQ. Impulse moved some vertical blinds by several mm.

Tue Aug 07 23:26:06 2012 

  1095   Tue Jan 29 13:49:02 2013 taraNotesEnvironmentleakage in the lab

There is a pool of water in the lab. It is localized only around the floor near the fume hood. I'm not sure where it comes from,but it drips down from the edge of the sink where there is a small pool of water on it. I'll keep an eye on it. If there is still more leakage, I'll contact pma to take a look.

I did not see anything yesterday, so I guess the leak just started last night.


  1334   Wed Sep 11 18:29:40 2013 EvanDailyProgressEnvironmentExtreme Makeover: CTN Edition

[Tara, Evan]

In preparation for tomorrow's sprinkler installation, we have removed any extraneous optics, cables, and electronic equipment on and around the table. Everything on the table is now covered by a drop cloth.

Attachment 1: IMG_20130911_181048.jpg
  1525   Fri Sep 19 12:01:13 2014 EvanDailyProgressEnvironmentNorth EOM heater

I added a 48 Ω kapton heater to the north resonant EOM. It's got 40 mA going through it right now; no loop yet.

  1535   Tue Dec 16 14:06:35 2014 Aidan, Kate, EvanSummaryEnvironmentTask list

Some tasks not included on the list:

  • Temperature loops
    • Cavities
    • Can
    • PMC
  • Noise candidates:
    • Scatter
    • RFAM
    • PDH loop noise
Attachment 1: algaasTasks.jpg
  1541   Mon Mar 30 14:29:25 2015 AidanSummaryEnvironmentCleaning underway

I've started removing a lot of the miscellaneous hardware from the lab (old pieces of Bosch framing, sheets of acrylic/plastic, etc). Some has gone into the ATF - we'll have to decide whether to keep it permanently or not. Right now, like Indiana Jones and the Last Crusade, I'm trying to see if there truly exists some space in this lab - or if it is a myth propagated though the ages. 

  1556   Wed Jul 29 15:25:05 2015 ranaDailyProgressEnvironmentwater shutoff

Saturday: 4 AM - 12 PM

  1557   Thu Jul 30 14:55:14 2015 Aidan, AntonioSummaryEnvironmentBroken light replaced - general lab cleanliness

I had Facilities come and replace the dead light tube in the CTN lab antechamber. It's nice and bright in there right now.

We've noticed that the floor is pretty dusty - so we're implementing twice weekly mopping sessions starting tomorrow.


  1559   Sat Aug 1 09:29:25 2015 AidanSummaryEnvironmentCleaned computer table. Added Acromag

I cleaned the table with the computers and removed one of the monitors. I installed the Acromag units to the rack, powered them up and got them onto the network. They are:

XT1221 unit:

XT1521 unit:

I've pinged them successfully from other machines. I have an Ubuntu machine that I borrowed from the TCS lab to interface to them. I'll set up the EPICS control on Monday. In addition to adding the DC transmission channels to Acromag, we should be able to start migrating the PID controls away from the VME crates to these new units. 



  1560   Tue Aug 4 11:28:48 2015 Antonio, AidanSummaryEnvironmentDC transmission channels to Acromag and floor cleaning

Yesterday the DC transmission (ISS photodiode, North cavity) channel to acromag has been added and the viewer has been set on the Ubuntu machine. The channel has been also calibrated (against voltage externally injected). We are going to add other channels from the VME crates and work on the PDH board interface in order to remote control this unit.

Additionally the floor has been sweeped and mopped.







  1589   Tue Oct 13 16:47:55 2015 Aidan, AntonioSummaryEnvironmentPEM monitor computer is ready to run - needs license

We've set up the PEM monitor computer to broadcast the temperature channels to EPICS.

  • Computer is a Windows machine at
  • Has OPC server installed to communicate with the Newport zCDR wireless unit
  • OPC server still needs a license. Currently terminates after 2 hours
  • OpcIocShell runs to create an EPICS IOC that interfaces with the OPC server and broadcasts the channels via EPICS.

We'll find a permanent home for the machine tomorrow.

  1608   Tue Jan 12 11:51:31 2016 AntonioSummaryEnvironmentTable legs

Table height

Currently the height of the optical table is 27.5" (see attached PDF). We would like to increase its height.


The legs are provided with a spacer http://www.newport.com/Pneumatic-Vibration-Isolators-with-Automatic-Re-Leveling/844255/1033/info.aspx 

which allow us to increase the height just by replacing the spacer (2.5").

The new spacers bring the height of the legs up to 28" (or 23.5") and the total height of the table up to 40"-41" (or 35"-36").


I ahave asked a quote for spacers which make the legs height equal to 28". They can come with flanges for horizontal bars. I have asked a quote

for this too.  We need to decide if this height is fine and if we want horizontal bars.




Attachment 1: table&legs.pdf
Attachment 2: table&legs_small.pdf
  1609   Wed Feb 24 19:20:16 2016 AntonioSummaryEnvironmentEnclosure legs
Enclosure legs cleaning
Before we install the enclosure with new legs some cleaning is required.
The legs are aluminum struts, not anodized! 
Today I first washed all pieces with water and soap, because
the amount of dirtiness was insane. Then I have used isopropyl and paper on all
of them (3 times). After that I focused only with one leg and still some oil is there.
I am not positive about us cleaning it unless we find some better way to do it.
  1610   Fri Mar 4 17:27:48 2016 AidanSummaryEnvironmentTable and enclosure raising

We have raised the table by ~ 16" and the enclosure around the table by about 13".

  • Feb-16: covered the table and removed the old enclosure. Equipment emptied from cupboards and stored in TCS lab
  • Feb-22: Transportation came across and raised the table for us.
  • Mar-3/4: Taller enclosure assembled around the table
Attachment 1: Feb16.zip
Attachment 2: Feb22.zip
Attachment 3: Mar03.zip
  1622   Tue Apr 5 16:16:14 2016 AntonioDailyProgressEnvironmentSprinkler

One of the last few steps left was to put back the sprinkler. Much more complicated and longer than I thought, but

It is Done!!!

  1640   Tue Jun 14 16:13:21 2016 awadeNotesEnvironmentLab tidying and cleanness

Tidying and ordering the PSL lab to bring about some greater order. 

While taking down some AC cables from the wall a large amount of flaky white particles were being released. I thought it was paint off the walls or maybe settled dust but it turned out to be an aged logistics barcode label (pictured). I've put it outside the door but we need to make a concerted effort to purge these from the lab along with the rest if the low grade paper products like corrugated cardboard boxs (also pictured).  

For now maybe don't open the tent while it settles and maybe we can track down something like a swifter mop to bring down the particle count in the lab. We also need to acquire a fresh sticky mat for the flow cabinet end of the lab and maybe an extra mat near the pull out draws to capture the foot traffic on the other side of the table for the next month or so.  






Attachment 1: image.jpg
Attachment 2: image.jpg
  1650   Sat Jun 25 19:25:38 2016 AntonioDailyProgressEnvironmentEnclosure sealed

I have ultimated the work started few months ago about sealing the enclosure with the tape to avoid air air flowing from the top.

The work has been completed.

  1713   Fri Sep 2 12:25:19 2016 awadeSummaryEnvironmentPEM monitor computer is ready to run - needs license

The Newport temperature, pressure, humidity remote sensor unit (zED-BTH) in the PSL lab was sitting on a recessed shelf of the work bench. This isn't a great location for accurately sensing and logging the lab temperature. I have now mounted it on the center of the western wall of the lab (pictured) 1.524 m from the ground. This location has free air flow.

Indicator LED also wasn't blinking. I checked the batteries and they were down to about 0.200 V for each of the AAs. I've replaced them as of today.  

It seems like these units have an email alert function: http://www.newportus.com/ppt/ZSERIES.html . Maybe we should set one up for battery replacement alarms.

Location of C3:Unit2 Newport zED-BTH sensor end unit



We've set up the PEM monitor computer to broadcast the temperature channels to EPICS.

  • Computer is a Windows machine at
  • Has OPC server installed to communicate with the Newport zCDR wireless unit
  • OPC server still needs a license. Currently terminates after 2 hours
  • OpcIocShell runs to create an EPICS IOC that interfaces with the OPC server and broadcasts the channels via EPICS.

We'll find a permanent home for the machine tomorrow.


  1716   Tue Sep 6 15:24:52 2016 AidanSummaryEnvironmentPEM monitor computer is ready to run - needs license
I'm working with Jamie to get a frame builder running in the ATF & CTN for these temp/pres/humidity channels to be stored on. There's no 
long term storage right now.
  1725   Tue Sep 27 18:32:13 2016 awadeMiscEnvironmentLab cleaning: testing different swiffer pads

I wasn't sure if wet or dry swifter pads would pick up more debris from the ground so I got sample packs of both. The dry ones seem to do ok and don't leave a surfactant residue or scent which can be overpowering after a few layers on the lab floor.

I ran the dry cloth type over the PSL lab and then the wet. This isn't really a good controlled experiment but you can see there wasn't so much left over for the wet (pad with green strip) to pick up. This would indicate that the dry pad got most of the dust.


Dry polyester swiffer cloth left, wet sweeper pad right. First pass with dry pad followed by wet pad.

The dry pads are made of felted polyester which quickly generates a electrostatic charge that draws in dust. With a simple test after rubbing over the floor, it seems statically attract and hold an optics cleaning tissue with reasonable strength.  The only issue is that it does have some small fibers, I'm not sure if any of these would escape, they seem reasonably contained within the pad.

  1806   Mon Jan 9 15:20:07 2017 awadeMiscEnvironmentPower outage in lab last night.

There was a power outage in the lab last night.

  2249   Fri Oct 12 14:41:17 2018 awadeSummaryEnvironmentTemperature logging PSL lab (Sep-Oct 2018)

Temperature data in the ATF (QIL) lab has been collected for a month now.  Data is sampled at 0.1 s intervals and saved on WS2. I'm not attaching the full data here (its about 4 Gb/month in csv format) but the minute trend is included along side the plots below.

Plotted below is the hour trend from September 11th up until October 13th 2018* (UTC).  

The Thermostate trace shows temperature as measured at the AC control sensor.  EnvMon is the themerature at the center of the table (sensor is mounted to table directly). 


*Note that these sensors were never calibrated for their absolute offset (but they should be pretty close).  Drift of the transducer box is unknown.  It uses a LT1128 op amp to convert AD590 sense current into voltage.  This is not the right choices.  Also the resistors are the lower grade radial type thick film, which is also not the best choice for immunity to circuit induced drift.

Attachment 1: 20181011_PSLLabTemp_Sep9toOct11_AbsUncal_HourTrend.pdf
Attachment 2: MinuteTrend_Sep_PSLLabTempData.tar.gz
  2589   Tue Sep 15 15:13:44 2020 AnchalNotesEnvironmentHEPA filters switched on. Measurement stopped.

I have switched on HEPA filters to high, both on top of the main table and on top of the flow bench.

Continuous measurement is stopped hereby. This experiment is finished.

  2607   Wed Jan 27 15:12:05 2021 AnchalNotesEnvironmentSmall leak or drip in the lab on West End

I noticed small amount of water on the floor (Attachment 1) on the west end of the lab. Immediately above it is a pipe which I don't know what it does. One can see another drop forming at the edge of this pipe (Attachment 2). This water is slowly dripping on the side of the pipe (Attachment 3). I could trace it out to coming from somewhere on the top (Attachment 4 and 5).

Maybe this is just some condensation because of increased humidity in the air. But maybe this is some troubling sign. What should I do?

Attachment 1: WaterOnTheFloor.jpg
Attachment 2: WaterDropForming.jpg
Attachment 3: PathToWaterDrop.jpg
Attachment 4: WaterDripZoomedOut.jpg
Attachment 5: PropbablyTheSource.jpg
  1928   Mon Sep 18 16:09:55 2017 johannesNotesEquipment loanBeam'R2-DD to 40m

Relocated dual slit scan beam profiler Beam'R2-DD to 40m lab. Anticipated time needed ~1 week.

  1965   Tue Oct 31 18:05:37 2017 ranaPhotosEquipment loanThe Case of the Missing Pink Case Camera


  2325   Wed Apr 17 10:40:54 2019 KojiSummaryEquipment loanBorrowing an IPA/Acetone glass bottoles CTN->OMC

I borrowed a small isopropanol glass bottle from CTN to OMC (Apr 17, 2019)

I borrowed a small acetone glass bottle, which was in the yellow solvent cabinet, from CTN to OMC (Apr 19, 2019)

  2336   Mon May 6 20:12:22 2019 AnjaliSummaryEquipment loanBorrowed components

I borrowed the following components from PSL lab to QIL lab 

1. Mixer (Minicircuit, ZFM-3-S+)

2. RF amplifier (Minicircuit, ZFL-500LN)

3. IFR/Marconi 2023 A (# BD9020)

  2590   Wed Sep 23 00:21:02 2020 aaronMiscEquipment loanHP 8560E SA to Cryo

I entered CTN just before (Wed Sep 23 00:22:11 2020 ) to borrow a spectrum analyzer, which I took to Cryo. Wore shoe covers, goggles. Sanitized goggles and door after.

  2591   Wed Sep 30 11:13:28 2020 anchalNotesEquipment loanTook home moku and wenzel crystal for characterization

I have brought home the following items from CTN Lab today:

  1. Moku with SD Card inserted and charger.
  2. Ipad pro with USB-C to USB-A charging cord
  3. Wenzel 5001-13905 24.483 MHz Crystal Oscillator
  4. HP E3630A triple output DC power supply
  5. One small 5/16 spanner
  6. 4 SMA-F to BNC-F adaptors
  7. 4 SMA-M to BNC-F adaptors
  8. 2 10 dB BNC Attenuators
  9. 4 BNC cables

Additionally, I got 4 BNC-Tee and a few plastic boxes from EE shop. Apart from this, I got a box full of stuff with red pitaya and related accessories from Rana.

  2596   Tue Nov 24 16:16:53 2020 anchalNotesEquipment loanTransferred moku to Cryo lab

I transferred the following form my home to Cryo lab (Cryo_Lab/2587) today:

  1. Moku with SD Card inserted and charger.
  2. Ipad pro with USB-C to USB-A charging cord
  2597   Tue Nov 24 16:23:26 2020 PacoMiscEquipment loanbroadband EOM

Borrowed 1 (new focus) broadband EOM from CTN for temporary use in Crackle (2 um OPO experiment)

  2601   Tue Dec 1 12:04:10 2020 RadhikaNotesEquipment loanBrought home low-noise preamplifier

I have brought home the following items (provided by Anchal):

1. Low-noise Preamplifier (Model SR560)

2. Two serial-to-USB adapters

  2602   Wed Dec 2 13:43:43 2020 anchalSummaryEquipment loanTransferred two gold box RFPDs to 40m

I transferred two Gold Box RFPDs labeled SN002 and SN004 (both resonant at 14.75 MHz) to 40m. I handed them to Gautam on Oct 22, 2020. This elog post is late. The last measurement of their transimpedance was at CTN/2232.

  2603   Mon Dec 7 19:02:26 2020 PacoNotesEquipment loanUPDH box

Borrowed Universal PDH box from CTN lab (D0901351) and a mounted Faraday isolator (Thorlabs) for use in Crackle.

  2604   Wed Dec 9 18:13:12 2020 PacoMiscEquipment loannew focus 1811

Borrowed two broadband PDs (new focus 1811) and one power supply unit (new focus 0901) from CTN into Crackle.

  2605   Tue Dec 15 12:59:14 2020 anchalNotesEquipment loanMoved Marconi and Rb Clock to Crackle lab

Moved the rack-mounted Marconi 2023A (#539) and SRS FS725 Rb Clock to crackle lab (See SUS_Lab/1876).

  2606   Wed Jan 27 15:11:13 2021 anchalNotesEquipment loanHP E3630A returned

I have brought back HP E3630A triple output DC power supply.


  2609   Tue Feb 23 11:05:28 2021 anchalNotesEquipment loanTook home moku and wenzel crystal for characterization

Returned all remaining stuff to CTN:

  1. Wenzel 5001-13905 24.483 MHz Crystal Oscillator
  2. One small 5/16 spanner
  3. 4 SMA-F to BNC-F adaptors
  4. 4 SMA-M to BNC-F adaptors
  5. 2 10 dB BNC Attenuators
  6. 4 BNC cables

Also returned the Red Pitaya accessory box to CTN. I've kept Red Pitaya at home for more playing.

  2611   Fri Jan 28 15:18:27 2022 AnchalSummaryEquipment loanCTN raided by 40m tribes

[Anchal, Paco]

CTN was raided today afternoon between 2 pm and 3 pm by 40m tribes. They have taken away precious Acromag units which are a very scarce resource these days. Following units were taken (Attachment 1):

  • 1 XT1111 from blue cabinet.
  • 4 XT1221 which were used at following places (see network):
    • |  | 00:01:C3:00:98:59  | CTN Lab  | Acromag XT1221: 8-Channel Differential Analog Voltage Input Module  (CTN Slow controls)|
    • |  | ?  | CTN Lab  | Acromag XT1221 8-Channel Differential Analog Voltage Input Module (Temperature Sensor monitor channels)  |
    • | | 00:01:C3:00:98:55  | CTN Lab  | Acromag XT1221: 8-Channel Differential Analog Voltage Input Module  (PMC North remote controls)|
    • |  | 00:01:C3:01:12:FF  | CTN Lab  | Acromag XT1221: 8-Channel Differential Analog Voltage Input Module  (PMC South remote controls)|

3 rack mount units were affected:

CTN Slow Controls chassis:

  • 2 XT1221 were removed from here. These can be installed back if Acromags become available and we need this experiment again
  • 1 XT1541 is still mounted on this chassis.

PMC Servo Card Chassis:

  • 1 XT1221 was removed from each servo card chassis (see attachment 2(North) -3 (South)).
  • These chassis are otherwise functional and one can repopulate the XT1221 to make them function again (see CTN/2248 for instructions).

All these units are stored in the flowbench side wire rack (see attachment 4).

Attachment 1: PXL_20220128_230302199.jpg
Attachment 2: PXL_20220128_230017489.jpg
Attachment 3: PXL_20220128_230000139.jpg
Attachment 4: PXL_20220128_230247003.jpg
  204   Thu Jul 8 19:55:42 2010 taraNotesFSSErr signal pk-pk vs RF adj

 Peter helped us enable the slow loop for the laser driver. The current setup is

P: +0.0001

I:   0.0000  (this is too sensitive, when I increase the gain by the smallest step, 0.0001, the system is out of lock)

D: 0.0000   


Also, after align the beam to the RefCav again. the transmitted beam from RefCav is much more stable.

 Reflected beam's Voltage on the RFPD is less than 20 mV when locked, and more than 496 mV when out of lock.

This corresponds to ~ 96% Transmission.

I measured the power spectral density of RFTRANSPD,

this is posted and compared to result we got from 40m on fig2.

*****This is done with slow loop(temperature) and fast feedback (pzt)  enabled, but PC feedback disconnected, because the gain is too high already.

Common gain is -2.5 dB,

Fast Gain is 15 dB.


The blue plot is the result from 40m, red and green are the results from PSL lab.

Green was measured while the HEPA filter above the table was on, Red was measured

when the HEPA filter was off. I measured 4 Frequency span for each plot, 100k, 10k ,1k and 100 Hz. 

The results from PSL (red and green plot) have jumps at 100 and 1 kHz

which I haven't figured out yet. The next plan is to reduce the gain,

so that PC feedback (faster than 100 Hz) can be enabled. 

Thus, the RIN above 100 Hz should be suppressed more.

To reduce the gain, the RF power (modulating index) must be decreased. I don't know the calibration yet,

so I measure the pk-pk value of the error signal vs the RF power adjustment and plot below (fig1.) This might be helpful

for determining the right value.



Attachment 1: FSSerr.png
Attachment 2: RIN_compare.png
  212   Tue Jul 13 14:46:23 2010 taraNotesFSSschematic for FSS servo

The current FSS servo we are using is labeled D980536 Rev. C on the PCB, but the schematic that matches the PCB more is D980536-D (there are minor corrections).

The schematic is posted below.

I'm checking If the board will match the schematic or not. Then its transfer function (TF) will be calculated by simulink, and compared with the result from measurement. 

The correction will be added soon.


Attachment 1: D980536-D.pdf
  271   Wed Aug 11 23:57:10 2010 Frank, PeterDailyProgressFSSFSS loop fixed

Peter and i solved the problem with the fss loop today, but here the long story:

The problem was that the loop was much more stable without the PC connected, so only the PZT of the laser was used as an actuator so far. Already some time ago i thought it might be the wrong sign for the PC and so i tried to change the sign of the loop by changing the two jumpers at the output going to the fast actuator and changing the sign of the error signal, but i never got it to lock in that configuration. So i though the other, previous configuration must be the right one, as it is locking. Later Tara had the same problems. The problem was that if the PC was connected the stability didn't increase and it even seemed to be more unstable using the PC in addition.

So in fact, the sign we used so far was the wrong one. But the problem was that changing the sign of the fast actuator and then flipping the error signal sign didn't work because the other (right) jumper settings don't work ! There is no feedback to the PZT of you change the two jumpers to the other orientation !! That's why it never worked with the right jumper positions.

As we figured out that this might be the problem i've build a BNC adapter changing the sign at the input of the laser and here we go, it's working now  So something is wrong with this board . I will figure that out later what exactly is broken on that board.

will measure the ugf of the fss loop tomorrow...

  358   Mon Sep 13 23:37:52 2010 taraDailyProgressFSSFSS debugging again

The FSS servo is not working. When SLOWDC which controls the NPRO temperature is brought to near resonance,

it falls off the lock when we enable the loop. So it's a debugging day.

First, I aligned the beam on RFPD, making sure that the beam is on the center, and align the beam to the cavity.

The signal from transmitted beam oscillates a lot. The gain was too high

(This is surprising, we haven't changed any power but the gain is too high already.) 

the set up is changed as follow

common gain, 16  --> 7

Fast gain,   15 --> 14

RF power  7.0 --> 7.2

Phase Adj  4.5 --> 3.92

Then I checked the error signal from MIXER OUT channel on FSS card. The signal looks fine.

The DC level is ~ 17 mW, peak to peak level of the carrier is 160 mV, and 39 mV for sidebands.

[the setup is:

RF power 7.0 V
Phase adj 4.5 V +180 flip]

The transfer function between In2 and fast mon seems fine.


Now the loop can be locked, but when FSS_FAST gets lower than -2 V. It runs away and lose lock.

This does not happen when it goes to plus sign. it can go up to 5 or 6 V before losing lock.

So we increased the RF power to maximum (10 V) which increases the error signal pk-pk to 394 mV.

FSS MON seems to stop railing, I'll adjust the gain setting again to minimize fluctuation in mixer out. 

  359   Tue Sep 14 11:52:34 2010 taraNotesFSSFSS servo debugging

After I increased the pk-pk of the error signal for RCAV system (by increasing the RF power to maximum), 

 C3:PSL-FSS_FAST is still railing once it goes below ~ -2 V kicking the system out of lock.

I'll check again if the laser is lock to the center of the error signal or not.

  583   Fri Apr 15 18:59:41 2011 taraDailyProgressFSSPreparing to install TTFSS

I'm preparing the cables for the new TTFSS. A cable for +/-220V is made.


I'm planning to install the new TTFSS.  I think the interface and the TTFSS can be fitted on the main PSL rack with power supplies below.

We need +/-17 V, +/-24V, and +/-200V. There is still at least one available KEPCO HV supply I can use.

The cable for +/-200V are almost ready. I went to Wilson house to get the appropriate cable and connector case.

I still need to find banana connectors for another end.

  584   Tue Apr 19 22:40:03 2011 taraDailyProgressFSSPreparing to install TTFSS


 All cables and power supplies for the new TTFSS are ready. I'll fire it up tomorrow.


 With Peter help, +/- 200V power supply is ready. I'll use the same power supply for the current FSS. I removed the cable for the current FSS, and installed the cable for the new TTFSS.

+/- 24V is already in used, I just added the connector for TTFSS on top of it.

+/-17V is prepared for temporary solution. I used two HP DC power supplies. There are two available KEPCO power supplies on the racks, but I could not turn them on for now. I have to find the manual and read it first.

  585   Wed Apr 20 17:54:52 2011 taraDailyProgressFSSPreparing to install TTFSS

TTFSS is not working properly yet. The signal from Fast out is distorted, but it still can lock the laser. All three actuators are being tested over night. Fine tuning has yet to be done. Once the temperature is settled, I'll measure the beat signal.


       I tried to lock the laser with the new TTFSS. There are three actuators, SLOW (thermal control), FAST (acts on PZT), and PC ( acts onEOM).  First, I locked the laser with FAST actuator only. PD input and LO input were removed from the old FSS card and connected to the TTFSS servo box.Then, I scanned the laser by modulating the laser frequency via laser's FAST input to check the error signal. The signal measured at mixer out, FAST MON, RAMP IN OUT2 (see fig 0, for where the outputs are) were good, see fig1 and fig2, but the signal from FAST OUT(tnc) is distorted, see fig3.

      Another problem was about the lemo output, it appeared that

     1)when I measured the signal from FAST OUT(lemo), I did not see any signal at all, and

     2)when I observed the distorted signal from FAST OUT(tnc) and plugged in a lemo connector to lemo FAST OUT, the signal from tnc also disappeared. The connector on the cable is the one we used for FSS, it should be working properly, but I will double check it. There might be shorted/ bad connections in the cable. It probably is the problem from the lemo connector on the board. When I did the test on the box 6 months ago, I used only FAST OUT(tnc).



fig0: a part of the schematic from TTFSS servo. FAST OUT has two output, tnc and lemo connectors. The full schematic can be found here.

I measured the signal from FASTM, RAMP IN OUT2, FAST OUT (tnc), and FAST OUT(lemo)



 fig1: signal from mixer mon



fig2 signal from fast out2 (similar to that from fast out mon (different in amplitude), so I post only this picture)



fig3: signal from fast out (which is fed to the laser)

  587   Sat Apr 23 11:40:09 2011 taraDailyProgressFSSPreparing to install TTFSS

 koji, tara

 The mystery about the distortion FASTOUT is solved. It actually works propperly.

From previous entry, the distortion in the error signal from FAST OUT is due to the low pass filter at 10 Hz just before the output.

The signal from tnc FASTOUT disappears when we plug in the lemo FASTOUT because the lemo cable we used has its polarity switched.

So it grounds the signal from TNC output as well.


     For an easy reference, I draw a cartoon diagram for the TTFSS circuit.

The small circles are SMA inputs,

the large circles with shadow are manual knobs,

the middle size circles are bnc outputs,

the diamonds are TNC outputs, and the half circles are bnc outputs for monitor.


ELOG V3.1.3-