40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
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ID Date Author Typeup Category Subject
  1571   Fri Aug 14 19:10:39 2015 AidanSummaryTempCtrlDropped lab temperature set point from 72F to 68F

At 7:07PM

 

  1572   Mon Aug 17 17:02:41 2015 AidanSummaryComputersAcromag binary outputs working - still can't control TTFSS box though

I managed to figure out the modbusDrv configuration settings to get the binary output of the Acromag working. I've updated the Wiki page to reflect this. I've wired the XT1541 DAC, BIO Acromag unit to the T1EN and T2EN channels on the TTFSS box but I still can't get remote control of it yet for some reason. When the PDH loop is closed and I switch the TTFSS box to REMOTE, the loop stays closed regardless of what I do to the binary outputs in EPICS.

https://nodus.ligo.caltech.edu:30889/ATFWiki/doku.php?id=main:resources:computing:acromag

  1573   Wed Aug 19 10:34:33 2015 AidanSummaryDAQBinary IO control of TTFSS box working - can lock PDH remotely

I've worked out how to get the binary IO to work with the TTFSS box so that we can activate switches in that unit. It wasn't working in the setup yesterday because of physics. Actually - there is a 10K pulldown resistor in the Acromag unit that attaches the output to ground. The actual circuit looks like this:

 

VCC (5V) --- (4.99K) --- T1EN -----|-----DIO0 ----(6.2V if DOUT set to 1)---- (10K) ------ | GND

.........   TTFSS...................................| ..............................ACROMAG ...............................................|

T1EN is measured by the switch-chip (SN74HCT157D, chip U3 in D040423) to determine whether it should be open or closed. We need to bring T1EN below 0.8V to get the TTL logic to work.

If DOUT is set to 1, then DIO0 and T1EN become the excitation voltage, 6.2V, and the switch circuit reads high. If DOUT is set to 0, the excitation voltage is removed and we just end up with a voltage divider and around 3.33V at T1EN - which does not register as low.

We can get around this by adding a smaller resistor, say 810 Ohms, in parallel to the 10K, to lower the effective resistance of the pull-down resistor to 750 Ohms. The maximum current the Acromag unit will have to supply is 6.2V/750 Ohms = 8.4mA.

So that's what I did. Now, when I switch DOUT to 1, I see 6.2V at T1EN and when I switch DOUT to 0, I see 0.669V at T1EN. The TTFSS box registers these as two different states and I can lock and unlock the PDH loop from EPICS.

  1574   Wed Aug 19 13:53:45 2015 AidanSummaryDAQDAC calibration for Acromag slow units

Volts (requested) to Counts

C = a1*V_req + a2

a1 = 3003.5 counts/Volt

a2 = -20.8285 counts

Entered counts (in +ve and -ve amounts) and measured the resulting voltage across the output. I'm not sure how stable this calibration is.

Attachment 1: Photo_on_8-19-15_at_1.51.33_PM.jpg
Photo_on_8-19-15_at_1.51.33_PM.jpg
  1575   Thu Aug 20 13:55:22 2015 AntonioSummaryFSSOLTF Transfer functions of the North loop

In order to have a better understanding of the FSS electronic boards we decided to take

open loop transfer functions (OLTF) of the FSS North cavity loop. In the same time we took 

the opportunity to verify that the broadband EOM is working. However this measurement will

be done again for a better quantitative analysis of the loop performances.

 

OLTF measured in the common path shows the shape due to the PZT and due to the EOM

paths as expected.The UGF has been pushed up to 170kHz. In the picture below we see the

traces corrisponding to the two different gain settings.

 

Connections:

  

Network Analyzer                           FSS

           RF          ----------->        EXC (Common)

           R            ----------->        OUT2 (Common)

           A            ----------->        OUT1 (Common)

 

These measurements have been done with the Switch Exc on located on FSS interface board

and with the following gain settings:

 

  Fine Common Fast Offset

Initial settings

580 312 240 506
High gain 950 950 950 506

 

 

 

OLTF measured in the FAST path have the connections applied at the Fast and the switch EXC on

the front panel turned on. This measurement has been taken with "high gain settings" of the previous

measurement.In the following pictures can be seen the previous OLTF too (green/red).

 

Connections:

 

Network Analyzer                           FSS

           RF          ----------->        EXC (Fast)   (front panel switch Exc ON)

           R            ----------->        OUT2 (Fast)

           A            ----------->        OUT1 (Fast)

 

 

PLEASE note these are not the total OLTF (relative to their path) because is still missing the transfer function

between OUT1 and OUT2 in both the paths Common and Fast.

 

I would like to model this loop, I need to figure out the best way to do it.

  1577   Thu Aug 27 17:11:43 2015 Aidan, AntonioSummaryBEATTrouble locking - 140kHz notes are switching supplies?

We tried locking the PLL today but failed. Looking at the beat note on the network analyzer revealed some 70/140kHz harmonics. We thought this might be what is preventing us from locking.

Rana suggested that these are from the switching power supplies (which switch at 70kHz). If so, this may be a red-herring. It's possible we're not trying with high enough gain settings ...

The large peak that is offset by about 50kHz is from the Marconi ... we can make it move around by changing the Marconi frequency.

Attachment 1: network_analyzer_140kHz.JPG
network_analyzer_140kHz.JPG
  1578   Wed Sep 2 22:13:47 2015 AntonioSummaryBEATPLL locking AGAIN

Description

As described in the elog entry n. 1577 we were not able to lock the PLL as has been described in elog n. 1570. I have started by playing with the two PDH gains of both loops (North and South) as this could have been causes of non tolerable noise in the PLL loop. I have also monitored the peaks described in entry n.1577 as we were suspicious for their preventing the PLL locking.

Conclusion

The PLL loop has been locked repeatedly after locking the cavities multiple times. This result has been achieved by setting the PLL gain on the SR570 at 20 (PLEASE NOTE I was not able to lock the PLL with any other gains settings). 

The peakes of entry n.1577 are not preventing us to lock the PLL.

 

Some settings:

North FSS interface: Common gain =700; Fast gain = 450; PID = 4.451V;

South FSS interface: Common gain = 850; Fast gain =  250; PID = 0.5527V;

Beat frequency = 69.6 MHz;

 

However these are not the only allowable settings for the gain, but the PDH loop gains are crucial for the PLL locking. Later I am going to give a quantitative analysis for our PDH loops in order to have them in a more stable and/or less noisy locking point.

  1585   Thu Oct 8 16:27:18 2015 AidanSummaryNoiseBudgetNoise Budget on MATLAB - RIN is possibly the reason locking sucks right now

After two straight days of trying to get iPython notebooks to run on my Mac and two different Ubuntu installations, I gave up in frustration and rewrote the simpler parts of Evan's noise budget code into MATLAB. The following Noise Budget (without any BeatNote measurement from the lab) represents an estimate of the current noise in the system.

Clearly, with the ISS OFF, we are hugely dominated by intensity noise. We will investigate if this is the reason that we can't lower the FM deviation on the Marconi below 300kHz/V.

 

Attachment 1: CTN_NoiseBudget.pdf
CTN_NoiseBudget.pdf
Attachment 2: NBCode.zip
  1586   Thu Oct 8 22:48:36 2015 ranaSummaryNoiseBudgetorder the heat shields

If you can't install python, you can run it all in the Sage Math Cloud for free.

Also, please post the final design for the heat shields which you've sent out for fab.

  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 10.0.1.35
  • 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.

  1591   Thu Oct 15 10:09:16 2015 AidanSummaryComputersUpdated network diagram on Wiki

https://nodus.ligo.caltech.edu:30889/ATFWiki/doku.php?id=main:resources:computing:network:menu

Removed a few old computers from the diagram (35W laser, old OPC server, PSL Workstation, HWS workstation). Added a few new ones (OPC server in TCS lab, New workstation in PSL lab, Acromag control box in PSL lab).

 

  1592   Fri Oct 16 22:24:35 2015 AntonioSummaryBEATPLL noise and beat frequency at 50MHz

Summary

Today the beat frequency was very difficult to find. Something changed, and I am not sure yet how to drive

the frequency of the beat. However the beat frequency is at 50MHz while so far it was at 64MHz. The PLL lock

more difficult and noisier.

 

Note:

Sometimes today or Yesterday we have increased the temperature of the lab (~ 2 degrees F).

 

Data:

lab computer/control fb2/home/data/20151016_PLL_noise_50MHz

  1596   Sun Oct 25 22:15:35 2015 AntonioSummaryEOMAEOM installed in the South path. Noise issue.

Summary

The AEOM has been installed in the South path replacing the EOM 21MHz used for the PMC. There is a high noise that I clearly see at the photodiode in transmission. 

 

When I have placed the AEOM in the path I have decided to take the alignment of the previous EOM as reference. Not ideal because the reference should be the incoming beam. The beam is not parallel to the table and it was decided to be as less as possible invasive. The mode matching and the alignment gave at that time 20% of visibility (at each polarization). After the installation parameters where unchanged. Later I have improved the alignment bringing the visibility at 30% for both the polarizations. After that, when everything was in place I have easily locked the cavity but the power in transmition was showing a very high noise. I have spent all the day trying to twick the alignment because and servo loop gain, but we need to solve this before going further. My back does not allow me to proceed for today.

 

NOTE:

I have also noted that the South Laser which is labeed 2W laser has the lambda/4 and the lambda/2 rotated in a way that at the output of FI we had few mm. I am not sure if damping the power at the FI is a good thing.

  1597   Mon Oct 26 13:47:18 2015 AidanSummaryRefCavThermal shield cap drawing - lower emissivity material

https://dcc.ligo.org/DocDB/0120/D1500213/001/D1500213-v1.PDF

  1598   Mon Oct 26 17:24:59 2015 AidanSummaryRefCavThermal shield cap drawing - lower emissivity material

Here's the drawing for the shield. https://dcc.ligo.org/LIGO-D1500403

 

Quote:

https://dcc.ligo.org/DocDB/0120/D1500213/001/D1500213-v1.PDF

 

  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
table&legs.pdf
Attachment 2: table&legs_small.pdf
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
  1611   Tue Mar 8 18:34:06 2016 AntonioSummaryPMCPMC preparation

This morning I sent an email to Evan in order to obtain PMC documentation. 

For now the only documents found is a mechanical drawing E1400332. I am aware of additional 2 documents that he wrote for this design. I also asked for the electronic/servo

instructions as I am not aware if he built/bought parts for the PMC servo.

 

This morning I have also poked Rich, in order to have advices on what type of epoxy we need to buy for pzt gluing. Not sure about that. I am going to investigate

on what to buy and especially what should be the best procedure for gluing.

 

We have been collected the materials bought from Evan:

1. Spacers;

2.  Mirrors;

3. PZTs;

 

Things to buy:

1. O rings;

2. Epoxy for PZT;

3. Screws;

 

I am considering to use the table in the TCN lab, once we have a functionally lab. All the information about the PMC will be collected in a section on the PSL wiki page.

  1612   Wed Mar 9 16:18:42 2016 AntonioSummaryPMCPMC preparation

O rings and screws have been ordered!!!

Quote:

This morning I sent an email to Evan in order to obtain PMC documentation. 

For now the only documents found is a mechanical drawing E1400332. I am aware of additional 2 documents that he wrote for this design. I also asked for the electronic/servo

instructions as I am not aware if he built/bought parts for the PMC servo.

 

This morning I have also poked Rich, in order to have advices on what type of epoxy we need to buy for pzt gluing. Not sure about that. I am going to investigate

on what to buy and especially what should be the best procedure for gluing.

 

We have been collected the materials bought from Evan:

1. Spacers;

2.  Mirrors;

3. PZTs;

 

Things to buy:

1. O rings;

2. Epoxy for PZT;

3. Screws;

 

I am considering to use the table in the TCN lab, once we have a functionally lab. All the information about the PMC will be collected in a section on the PSL wiki page.

 

  1618   Wed Mar 30 10:22:59 2016 AidanSummaryDAQNew front panel for Acromag slow controls ordered

I've ordered a 4U rack mount kit with DIN rail for mounting the Acromag stuff. It's open on the top and bottom but is quite deep. I've made up a front panel for this kit which will connect to the slow controls with 8 analog inputs, 8 analog outputs, 4 binary inputs/outputs, 2x 25 pin connectors for connecting to the FSS boards and a 15 pin connector for connecting to the ion pump current supply.

 

Attachment 1: D1600135-v1_Acromag_front_panel2.pdf
D1600135-v1_Acromag_front_panel2.pdf
  1628   Sat Apr 9 12:30:15 2016 AidanSummaryDAQDAC back online for laser SLOW control: now via Acromag

With the (intentional) demise of the VME crate, the slow controls for the laser were brought back online today. So far, only the controls for the laser temperature are running. However, if you run the LASER SLOW MEDM screen, the channels C3:PSL-ACAV_SLOWOUT and C3:PSL-RCAV_SLOWOUT are now active. 

To achieve this: I did the following:

1. Restored FB2 to the local network to allow for GUI interface to EPICS.

2. On the computer running the MODBUS IOC (10.0.0.33), I created some channels in the DB that are "ai" channels with the names C3:PSL-A(R)CAV_SLOWOUT. There are some CALC channels that use these as inputs to convert to counts and then the output is sent to the approrpiate DAC register on the acromag unit via the modbus protocol.

3. So now any computer running EPICS on the local network can interact with the SLOWOUT channels

We connected BNCs up between the Acromag terminals and the SLOW IN BNC inputs on the front panel of the two NPRO controllers and double-checked that a requested voltage actually yields that voltage at the NPRO controller.

 

  1629   Sat Apr 9 12:30:20 2016 AidanSummaryDAQDAC back online for laser SLOW control: now via Acromag

With the (intentional) demise of the VME crate, the slow controls for the laser were brought back online today. So far, only the controls for the laser temperature are running. However, if you run the LASER SLOW MEDM screen, the channels C3:PSL-ACAV_SLOWOUT and C3:PSL-RCAV_SLOWOUT are now active. 

To achieve this: I did the following:

1. Restored FB2 to the local network to allow for GUI interface to EPICS.

2. On the computer running the MODBUS IOC (10.0.0.33), I created some channels in the DB that are "ai" channels with the names C3:PSL-A(R)CAV_SLOWOUT. There are some CALC channels that use these as inputs to convert to counts and then the output is sent to the approrpiate DAC register on the acromag unit via the modbus protocol.

3. So now any computer running EPICS on the local network can interact with the SLOWOUT channels

We connected BNCs up between the Acromag terminals and the SLOW IN BNC inputs on the front panel of the two NPRO controllers and double-checked that a requested voltage actually yields that voltage at the NPRO controller.

 

  1632   Fri Apr 15 20:59:38 2016 ranaSummaryDAQDAC back online for laser SLOW control: now via Acromag

The old 3123 cards were 16-bit ADCs. Are the acromag units 16 or 12 bit? Also, what about the DAC range? I would not drive the laser directly through the DAC without a low pass.

  1633   Fri May 27 21:10:54 2016 AntonioSummaryFSSFSS frequency modulation

Summary

Analysis of the frequency modulation for the FSS loop has been done (may be I have repeated it )

as we want to increase the frequency modulation from the current 21.5MHz to something

bigger than something like 30MHz.

 

Higher order mode analysis

I have considered a cavity of length L=3.45’’=3.68cm and radius of curvatures R1=R2=1m.

 

1.

Plot 1 shows the frequency distance vs frequency modulations. I care that HOM (Carrier and

SBs) do not overlap with carrier and SBs TEM00. The closest mode is the number 23 which

interfere with the positive SB around 31MHz. I do not consider this to be a problem, but I go head

anyway. At that frequency we also see the mode 46 crossing the the SB (TEM00).

 

 

 

2.

In order to better visualize the distances shown in the previous plot I use the minimum distances from the TEM00 (carrier or SBs).

The minimum distances are referred to the closest mode which may change along the SBs scan.

We see that on 31.7mHz we have a minimum as noticed previously and it is because of the mode 23.

From here if we would like to avoid the mode 23 I would choose a frequency modulation of ~39MHz.

 

 

 

3.

I fix the frequency modulation at 39MHz

I wanted to check if the mode 23 can be “avoided”. I consider the tolerance on L as L+- 0.0005 and Rc of +-1cm

There is a chance that the mode 23 overlap depending on what the variations from the nominal values are.

 

 

However the same is going to happen if we fix the Frequency modulation at 35MHz. So between  35MHz and 39MHz

I do not see substantial differences. (Please note that the color are normalized at 1MHz detuning from carrier).

 

4. While the scan of L and Roc has been done I have checked that no other HOMs come into play. The mode 23 and 46 are

the modes which determins the red lines at the point 3.

 

5. Mode distances at 35MHz and 39MHz.

 

 

 

From what I see here 35MHz is fine as mode 23 is the closest one to TEM00. As a reminder the pole of the cavity is ~180kHz. In principle 35MHz would be 4MHz

apart considering the nominal values L=3.68cm and RoC=1m.

 

Attachment 1: 12513925_1727410510814518_3994824814680966863_o.jpg
12513925_1727410510814518_3994824814680966863_o.jpg
Attachment 2: FMOD_HOMlinear_cav_L3.68cm_R1m.pdf
FMOD_HOMlinear_cav_L3.68cm_R1m.pdf
Attachment 3: HOMdist_cav_L00368cm_R1m.pdf
HOMdist_cav_L00368cm_R1m.pdf
Attachment 4: HOMdistmin_DL_DR_39MHz.pdf
HOMdistmin_DL_DR_39MHz.pdf
Attachment 5: HOMdist_check_35MHz.pdf
HOMdist_check_35MHz.pdf
Attachment 6: HOMdist_check_39MHz.pdf
HOMdist_check_39MHz.pdf
  1634   Mon May 30 14:27:48 2016 AidanSummarySafetyGave Andrew Wade a safety walkthrough

I showed Andrew Wade the CTN lab and gave him a safety walkthrough. We also went over the safe operating procedure for turning on the laser.

  1636   Tue May 31 13:26:21 2016 AidanSummaryRF36MHz and 37MHz Wenzel crystals added to the lab for PDH

I have a set of two Wenzel OCXO added to the electronics chassis, courtesy of the gentry from the Cryo Lab. The chassis has outputs for 36MHz and 37MHz.

We can use these temporarily and exchange the oscillators in future when we select a new sideband wavelengh.

Attachment 1: IMG_5250.JPG
IMG_5250.JPG
  1654   Wed Jun 29 15:57:13 2016 awadeSummaryInventoryList of current available lenses in PSL and 40m labs

As we are doing mode matching I compiled a list of presently available lenses to save time looking or ordering. See below.

A dynamically updated version is here: https://docs.google.com/spreadsheets/d/1x4-VQ85Wl7kGUH-V7HffCr6B7wIcD1y3VxXO4j6H5T0/edit?usp=sharing (this may not be a stable link far into the future)

At the time of posting the list is as follows:

Code Vendor Type ROC1 ROC2 n f location note
KBC040 Newport Bi-Concave       -75.00 40m  
KBC043 Newport Bi-Concave       -50.00 40m  
KBC046 Newport Bi-Concave       -25.00 40m  
KBX043 Newport Bi-Convex       19.00 40m  
KBX046 Newport Bi-Convex       25.40 40m  
KBX064 Newport Bi-Convex       100.00 40m  
KBX064.AR.33 Newport Bi-Convex       100.00 40m  
KBX088 Newport Bi-Convex       1000.00 40m  
KPC028 Newport Plano-Concave       -200.00 40m  
KPC031 Newport Plano-Concave       -150.00 40m  
KPC034 Newport Plano-Concave       -100.00 40m  
KPC037 Newport Plano-Concave       -75.00 40m  
KPC043 Newport Plano-Concave       -25.00 40m  
KPX076 Newport Plano-Convex       25.00 40m  
KPX079AR.18 PCX Lens, BK7 Newport Plano-Convex       38.10 40m  
KPX115AR.33 PCX BK7 Newport Plano-Convex       400.00 40m  
LA1172-C Thorlabs Plano-Convex       400.00 40m Thorlabs pre-mounted
LA1464-C Thorlabs Plano-Convex       1000.00 40m Thorlabs pre-mounted
LA1484-C Thorlabs Plano-Convex       300.00 40m Thorlabs pre-mounted
LA1509-C Thorlabs Plano-Convex       100.00 40m Thorlabs pre-mounted
LA1908-C Thorlabs Plano-Convex       500.00 40m Thorlabs pre-mounted
LA1951-C Thorlabs Plano-Convex       25.40 40m Thorlabs pre-mounted
LA1978-C Thorlabs Plano-Convex       750.00 40m Thorlabs pre-mounted
LB1056-C Thorlabs Bi-Convex       250.00 40m Thorlabs pre-mounted
LB1391-C Thorlabs Bi-Convex       400.00 40m Thorlabs pre-mounted
LB1409-C Thorlabs Bi-Convex       1000.00 40m Thorlabs pre-mounted
LB1471-C Thorlabs Bi-Convex       50.00 40m Thorlabs pre-mounted
LB1475-C Thorlabs Bi-Convex       750.00 40m Thorlabs pre-mounted
LB1761-C Thorlabs Bi-Convex       25.40 40m Thorlabs pre-mounted
LB1779-C Thorlabs Bi-Convex       300.00 40m Thorlabs pre-mounted
LB1869-C Thorlabs Bi-Convex       500.00 40m Thorlabs pre-mounted
LB1901-C Thorlabs Bi-Convex       75.00 40m Thorlabs pre-mounted
LB1904-C Thorlabs Bi-Convex       125.00 40m Thorlabs pre-mounted
LC1715-C Thorlabs Plano-Concave       -50.00 40m Thorlabs pre-mounted
LC2297-C Thorlabs Plano-Concave       -25.00 40m Thorlabs pre-mounted
LC2679-C Thorlabs Plano-Concave       -30.00 40m Thorlabs pre-mounted
LD1170-C Thorlabs Bi-Concave       -75.00 40m Thorlabs pre-mounted
LD1464-C Thorlabs Bi-Concave       -50.00 40m Thorlabs pre-mounted
LD2297-C Thorlabs Bi-Concave       -25.00 40m Thorlabs pre-mounted
PLCX-25.4-103-UV-1064 CVI Plano-Convex 1.00E+99 103 1.44963 229.08 PSL  
PLCX-25.4-103.0-UV-1064 CVI Plano-Convex 1.00E+99 103 1.44963 229.08 40m  
PLCX-25.4-1030.2-UV-1064 CVI Plano-Convex 1.00E+99 1030.2 1.44963 2291.22 40m  
PLCX-25.4-12.9-C-1064 CVI Plano-Convex 1.00E+99 12.9 1.5066 25.46 40m  
PLCX-25.4-13.1-UV-1064 CVI Plano-Convex 1.00E+99 13.1 1.44963 29.14 40m (Chipped)
PLCX-25.4-154.5-UV-1064 CVI Plano-Convex 1.00E+99 154.5 1.44963 343.62 PSL  
PLCX-25.4-1545.0-C-633-1064 CVI Plano-Convex 1.00E+99 1545 1.5066 3049.74 40m  
PLCX-25.4-180.3-UV-1064 CVI Plano-Convex 1.00E+99 180.3 1.44963 401.00 PSL  
PLCX-25.4-180.3-UV-1064 CVI Plano-Convex 1.00E+99 180.3 1.44963 401.00 PSL  
PLCX-25.4-20.6-UV-1064 CVI Plano-Convex 1.00E+99 20.6 1.44963 45.82 PSL  
PLCX-25.4-257.5-UV-1064 CVI Plano-Convex 1.00E+99 257.5 1.44963 572.69 PSL  
PLCX-25.4-257.5-UV-1064 CVI Plano-Convex 1.00E+99 257.5 1.44963 572.69 PSL  
PLCX-25.4-257.5-UV-1064 CVI Plano-Convex 1.00E+99 257.5 1.44963 572.69 PSL  
PLCX-25.4-2575-C-1064 CVI Plano-Convex 1.00E+99 2575 1.5066 5082.91 40m  
PLCX-25.4-309.1-UV-1064 CVI Plano-Convex 1.00E+99 309.1 1.44963 687.45 PSL  
PLCX-25.4-309.1-UV-1064 CVI Plano-Convex 1.00E+99 309.1 1.44963 687.45 PSL  
PLCX-25.4-309.1-UV-1064 CVI Plano-Convex 1.00E+99 309.1 1.44963 687.45 PSL  
PLCX-25.4-357.5-UV-1064 CVI Plano-Convex 1.00E+99 357.5 1.44963 795.10 PSL  
PLCX-25.4-38.6-UV-1064 CVI Plano-Convex 1.00E+99 38.6 1.44963 85.85 PSL  
PLCX-25.4-46.4-UV-1064 CVI Plano-Convex 1.00E+99 46.4 1.44963 103.20 PSL  
PLCX-25.4-46.4-UV-1064 CVI Plano-Convex 1.00E+99 46.4 1.44963 103.20 PSL  
PLCX-25.4-51.5-UV-1064 CVI Plano-Convex 1.00E+99 51.5 1.44963 114.54 PSL  
PLCX-25.4-515.1-UV-1064 CVI Plano-Convex 1.00E+99 515.1 1.44963 1145.61 PSL  
PLCX-25.4-64.4-UV-1064 CVI Plano-Convex 1.00E+99 64.4 1.44963 143.23 PSL  
PLCX-25.4-77.3-UV-1064 CVI Plano-Convex 1.00E+99 77.3 1.44963 171.92 40m  
PLCX-25.4-77.3-UV-1064 CVI Plano-Convex 1.00E+99 77.3 1.44963 171.92 40m  
PLCX-25.4-772.6-UV-1064 CVI Plano-Convex 1.00E+99 772.6 1.44963 1718.30 40m  
SPX028AR.1 PLXLens, UV Newport Plano-Convex       200.00 40m  
Unspecified Unspecified Unspecified       100.00 40m  
  1656   Fri Jul 1 16:50:35 2016 Aidan, AndrewSummaryDAQAcromag slow controls back up

I showed Andrew how to set up the slow controls. We got the previous 3 ADC channels back up.

  • C3:PSL-TRANS_ACAV_ISS_DC
  • C3:PSL-TRANS_RCAV_ISS_DC
  • C3:PSL-TRANS_RF_DC

Also:

  • rewired a few BNC feedthroughs up through the front panel of the Acromag chassis
  • bolted the front panel to the chassis independently of the screws that mount the chassis to the rack

 

Attachment 1: IMG_6196.JPG
IMG_6196.JPG
  1658   Sat Jul 2 11:06:03 2016 AntonioSummaryFSSFSS frequency modulation 2

Summary (Entry 1633 revised)

Analysis of the frequency modulation for the FSS loop has been done 

as we want to increase the frequency modulation from the current 14MHz to a

higher frequency in the range of 25 to 45 MHz in order to increase the FSS  unity

gain frequency. Below 25MHz we do not have too much benefit as currently we

are modulating at 14MHz. Above 45MHz we have photodiodes noise and we want to 

deal with that.

 

Higher order mode analysis

I have considered a cavity of length L=3.45’’=3.68cm and radius of curvatures R1=R2=1m.

 

1.

Plot 1 shows the detuning frequency vs frequency modulations. We care that HOMs (Carrier and 

SBs) do not overlap with the carrier TEM00. The closest mode is the number 23 which

interfere with the TEM00 around 31MHz. I do not consider this to be a problem. The morde order

is ment to be as the sum of n and m. The legend shows color of the modes in a dashed style. However

each mode order is showed with carrier (solid line) a positive SB (dash-dot) and negative SB (dashed).

 

 

From this plot we can see that in the range 25MHz to 45MHz we are pretty safe from HOMs overlaps.

 

If we care of the mode 23 than we should consider modulation frequencies above ~35MHz at least.

 

I consider a cavity pole of 135kHz (see elog 1480 https://nodus.ligo.caltech.edu:8081/CTN/1480)

 

 

 

2.

Plot 2 shows a zoom-in version of plot 1.

 

 

3.

In order to better visualize the difference between the detuning frequency from TEM00 and the closest HOMs (either carrier or sidebands) 

I provide the following plot. Please keep in mind that in general this way to plot the differences does not take in account of

which mode order is the closest. However in this case it is only the mode order 23.

 

 

 

We see that at 31.3MHz we have a minimum as noticed previously and it is because of the mode 23.

 

Choice of the Modulation Frequency

 

Currently in the TCN lab we have two oscillators; one is at 36MHz and the other one is at 37MHz; I was tempted to use them

 

but Rana suggested to have 2MHz separation between the two modulation frequencies in order to avoid to see noise in the beat note 

 

after the demodulation process.

 

 

So if we want to use one of them we can pick 37MHz and buy a 40MHz one.

 

If we have to buy two of them anyway we can go for the same 37MHz and 40MHz or shift a bit the frequencies to 39MHz and 41MHz.

 

 

I would pick 37MHz and 40MHz leaving the option to buy or not buy the second 37MHz.

 

 

Before buying all the parts and do all the work which is consequent at this choice, it is good to have some comments/opinion!

 

 

 

 

 

 

Attachment 1: HOMlinear_cav_L3_68cm_R1m_V2.pdf
HOMlinear_cav_L3_68cm_R1m_V2.pdf
Attachment 2: HOMlinear_cav_L3.68cm_R1m_V2_zoom_in.pdf
HOMlinear_cav_L3.68cm_R1m_V2_zoom_in.pdf
Attachment 3: HOMdist_cav_L3.68cm_R1m_V2_zoom_in.pdf
HOMdist_cav_L3.68cm_R1m_V2_zoom_in.pdf
  1694   Mon Aug 1 18:47:58 2016 awadeSummaryPLLPresent electronic configuration of the PLL loop

Post documenting the set out of the PLL electronics and cable routing.

We were having trouble with the PLL electronics in obtaining a beat note error signal and lock. We can see a beat note of 17 dB clearance above the DN level on the spectrum analyzer.   This post is to document the present configuration and the powers present at the mixer before I start to troubleshoot (aka pull it apart).

Schematic of the PLL electronics stage attached below.  Settings for the Marconi and SR560 are also below. I would noted that there is a low pass filter on the output of the phase detector (which I assume is a mixer) that extracts the (omega_LO - omega_sig) but has nowhere for the dumped (omega_LO + omega_sig) signals to go.  I'm guessing the non-DC signals are getting reflected directly back into the ZRPD-1+. I can't imagine that is great if back reflections start to form parasitic competing signals with the beat note signal.

PLL Loop electronics

Marconi 2023A
Carrier Frequency = 75.526 MHz (close to PD beatnote)
RF Level = +13 dBm
FM Devn 10.0 kHz (set by Ext DC)

SR560
Filter cutoff = DC
Coupling = DC
Source  = A (B port terminated with 50 ohm)
Inv = On
Gain Mode = Low noise
Gain  = 50
 

The spec sheet for the ZRPD-1+ indicates that it is a Level 7 mixer with a damage threshold at 50 mW, so the +13 dBm probably isn't a risk but may be saturating the mixer.  I don't have a calibrated power level for the RF PD input, but it is low (definitely not +7 dBm).  At this stage we either need to improve the beat note or implement some kind of amplification so that both the PD-RF input and LO inputs into the phase detector are matched at the ideal +7dBm level. 

At this stage both PDH control loops are ringing with DC signals that are very angular (and about 10% of the total DC signal). The angluarness would indicate that they are probably both railing somewhere or converting an control-error signal to amplitude modulations.  Previously we have diagnosed this back to imperfect polarization input into the fast control BB-EOMs.  I checked both North and South path and the inputs to the all EOMs (the 14 MHz and fast control) are very well aligned to 's': modulator polarization is not the issue. Antonio had this very well optimized form yesterday.

Tuning laser temperature around on the north path, it is apparent that there are some new/stronger HOMs around the region of our TEM00 modes. This is only a qualitative observation. It is possible that over time our mounts have drifted and the alignment is off.  This is now on my list of things check and to tune up.  

At this stage the PDH loop issues need to be resolved as they are impeding efforts to reliably form an observable beat note.

The process of unlocking and re-configuring for alignment and other types of diagnostic measurements is cumbersome.  There are BNCs popping out of the experiment everywhere that are also mostly unlabeled.  It would be much nicer to have all the useful control signals and PD signals coming out at a central point, preferably next to the computer interface and electronics rack where we lock and tune gains/temperatures.  I will gradually start migrating the cabling over to that side of the table and then install labeled 'patch lines' that are routed to mounted BNC panels around the table. This way there is a central location close to where we perform locking etc but it is relatively easy to patch through signals and oscilloscope trigger lines for temporary oscilloscopes situated around the table. This also means that consistent labeling can be applied.

It is not a great idea to label the cables with label-writer tape or color code them with electrical tape.  From experience the glues in these breakdown in 2-5 year timeframes either flaking off or leaving a sticky residue that is almost impossible to remove with solvents that don't also dissolve the BNC cable plastic. Heatshink can be good as it can be cut off and doesn't have glue. Otherwise a cable tied labels work well. We have some of these.

It also distresses me a little that BNCs cables are routing HV around the table without a clear system for distinguishing these cables. By Murphy's law these will one day be plugged into something sensitive. Some of them are labeled by are not marked clearly as HV. If I can find some red heat-shrink that fits over the ends of the BNC cables I might start labeling HV lines with a consistent markings to lower the risk of mix ups. 

 

 

Attachment 1: 20160801_ElectronicLayoutOfPLLLoop.pdf
20160801_ElectronicLayoutOfPLLLoop.pdf
  1700   Thu Aug 4 15:15:32 2016 AidanSummaryTempCtrlRTDs used in aLIGO TCS RHs

These are the RTDs we use in aLIGO TCS

http://www.omega.com/Temperature/pdf/1PT100KN_2PT100KN.pdf

 

  1701   Thu Aug 4 18:01:03 2016 ranaSummaryTempCtrlRTDs used in aLIGO TCS RHs

The heater driver in the old design (iLIGO PSL) is this horrible programmable power supply with high output noise (see measurement of 40m PSL heater).

What we want instead is something that takes in +/- 10 V and drives a DC current (not PWM) into our heaters (which are ~50-100 Ohms). A BUF634 is almost good enough; it can do 200 mA at 10 V. Is there a BUF634 equivalent which can do more like 500 mA? Otherwise we can just use a opamp + transistor.

What is being used for the ring heaters at the LIGO sites?

  1702   Fri Aug 5 00:08:16 2016 awadeSummaryTempCtrlRTDs used in aLIGO TCS RHs

I assume the key parameters are the noise characteristics here.  They seem to commonly quote the input noise voltage which I'm guessing gives a measure of the equivalent noise injected by the buffer itself. 

Data sheets list the input noise voltage of the BUF634 as 4  nV/√Hz @ 10 kHz . There is another buffer (300 mA), the LMH6321, its datasheet claims  input voltage noise 2.8 for >=10 kHz. I don't know what this means for noise at mHz.

Is there a reason we can't just buffer with more general purpose high current OP Amp? Is the the noise just a killer for that whole catalog of devices? Looking at a random selection, all the ones I've looked at have higher input noise voltage values but the digi-key product selector doesn't let me filter for noise characteristics so maybe there are low noise ones. 

 

 

 

Quote:

The heater driver in the old design (iLIGO PSL) is this horrible programmable power supply with high output noise (see measurement of 40m PSL heater).

What we want instead is something that takes in +/- 10 V and drives a DC current (not PWM) into our heaters (which are ~50-100 Ohms). A BUF634 is almost good enough; it can do 200 mA at 10 V. Is there a BUF634 equivalent which can do more like 500 mA? Otherwise we can just use a opamp + transistor.

What is being used for the ring heaters at the LIGO sites?

 

  1708   Sat Aug 27 17:42:40 2016 awadeSummaryTempCtrlHeat load of vacuum can held above room temperature.

Here are some numbers on the heat radiated away from the vacuum can by leakage through the foam insulation and from the exposed metallic parts. The heat loss is dominated by the foam as it has an larger surface area. However, these numbers are maybe a little rough as they don't account for the Al foil cladding on the outside and ignore the details of the cylindrical geometry.  

I've been working on documenting the thermal aspects of the vacuum can.  Info is spread across the elog in various places but not in one place.  This stuff is gradually getting added to the wiki which will be the central collecting point for information to avoid this iterative amnesia.  I am also almost finished on a graphic that summarizes the setout of the vacuum can and its sensors. This is just the heat loading calculations.

The tank is 22" long with 8.3" tube diameter with two 10" flanges on the ends.  This apparatus is clad all around by 2" (average) thick CertiFoam 25 see post PSL:178 for characteristics (note that Frank's values are for 1" thickness only, this must be scaled to the thickness used). Total dimensions of the foam box are 12x12x36" giving a surface area of ~1.3 m^2.  For a tank held at 35 C above room temperature 20 C this is 11.3W of heat loss.

At the top of the vacuum can there are three half nipples welded along the top, these hang out above the insulation as access is needed for the turbo/roughing pump connection, the ion pump and the sub-D 9 feedthrough. The exposed surface is a mix of shiny stainless steel and matt/sandblasted bits.  Shiny and matt exposed areas are respectively 0.0296 m^2 and 0.0168 m^2 (not including the ion pump) which is not big.  With emmisivities of 0.09 and 0.18 for these two surface types we get a total of 0.5265 W radiative heat dissipation for a tank held at 35 C above 20 C room temperature.  

Thus total estimated heat for a 35 C tank is 11.78 W. We don't need to run it at this temperature but I use it as a reference value.  See attached graph for heat loss as a function of vacuum can temperature.

A summary of these numbers and details is in the attached matlab file.

---

For reference the tank has 4 resistive heating mats wrapped around it. The small ones near the ends are 30 Ohm and the two larger ones near the center are 70 ohms each. These have been connected in parallel+ series network that gives a total resistance of 50 Ohms and can be driven with up to 115 V.  To just maintain the tank at 35 C we would need 24.5 V with ~0.5 A. This seems like a lot but is almost doable with available OPAMP buffers.

---

The next step is to work out heat capacity. I can't find design drawings for the tank itself on the elog/wiki, maybe its too far back in ancient history. There is a solidworks drawing on the SVN but was made in the student version of solidworks so is very buggy.  I will try an extract numbers to get an idea of the mass of metal in the tank. 

Also in progress is a step function measurement of tank cooling.  I spent some of this week working out how to integrate a new RTD acromag card into our existing EPICS setup so we can log the temperature drop after heating is turned off.  This took a while as I was unfamiliar with this kind of setup and also the power supply turned out to be not doing what I thought it was. The voltage current source is now hooked up and a thermister fitted for logging temperature. This measurement should give us some more grounded numbers on the real characteristics of the tank thermal decay rates.

 

Attachment 1: ThermalLoadCalculations_v2.eps
ThermalLoadCalculations_v2.eps
Attachment 2: ThermalLoadCalculations_v2.m
% This m file contains estimates for the heat radiativly disapated from the
% coating thermal noise experiment vacuum can.  
%
% I'm not sure if this has been done before but here are some numbers
% summerized in one place.
%
%
% Author: Andrew Wade
% Date: August, 2016
% Mods:
... 57 more lines ...
  1709   Mon Aug 29 19:09:19 2016 awadeSummaryTempCtrlHeat load of vacuum can held above room temperature.

To verify estimates of the heat load and thermal inertia of the system I am conducting a simple step test of the vacuum can heating.

The resistive heaters on the vacuum can were given a steady DC 35 V over the day, the system settled on an equilibrium temperature of 46.14±0.05 C. The location of the thermistor is shown on the picture attached. It took a long time because I initially used a fairly low current power supply (0.5A).  I switched this out for a 3.0 A, 0-60 V supply which was sufficient with the 50 Ohm heaters. 

I have left the tank to cool down (starting at time stamp 18:50:00, Aug 29) with the Acromag cards logging the decay back to room temperature.

 

 

 

Quote:

Here are some numbers on the heat radiated away from the vacuum can by leakage through the foam insulation and from the exposed metallic parts. The heat loss is dominated by the foam as it has an larger surface area. However, these numbers are maybe a little rough as they don't account for the Al foil cladding on the outside and ignore the details of the cylindrical geometry.  

I've been working on documenting the thermal aspects of the vacuum can.  Info is spread across the elog in various places but not in one place.  This stuff is gradually getting added to the wiki which will be the central collecting point for information to avoid this iterative amnesia.  I am also almost finished on a graphic that summarizes the setout of the vacuum can and its sensors. This is just the heat loading calculations.

The tank is 22" long with 8.3" tube diameter with two 10" flanges on the ends.  This apparatus is clad all around by 2" (average) thick CertiFoam 25 see post PSL:178 for characteristics (note that Frank's values are for 1" thickness only, this must be scaled to the thickness used). Total dimensions of the foam box are 12x12x36" giving a surface area of ~1.3 m^2.  For a tank held at 35 C above room temperature 20 C this is 11.3W of heat loss.

At the top of the vacuum can there are three half nipples welded along the top, these hang out above the insulation as access is needed for the turbo/roughing pump connection, the ion pump and the sub-D 9 feedthrough. The exposed surface is a mix of shiny stainless steel and matt/sandblasted bits.  Shiny and matt exposed areas are respectively 0.0296 m^2 and 0.0168 m^2 (not including the ion pump) which is not big.  With emmisivities of 0.09 and 0.18 for these two surface types we get a total of 0.5265 W radiative heat dissipation for a tank held at 35 C above 20 C room temperature.  

Thus total estimated heat for a 35 C tank is 11.78 W. We don't need to run it at this temperature but I use it as a reference value.  See attached graph for heat loss as a function of vacuum can temperature.

A summary of these numbers and details is in the attached matlab file.

---

For reference the tank has 4 resistive heating mats wrapped around it. The small ones near the ends are 30 Ohm and the two larger ones near the center are 70 ohms each. These have been connected in parallel+ series network that gives a total resistance of 50 Ohms and can be driven with up to 115 V.  To just maintain the tank at 35 C we would need 24.5 V with ~0.5 A. This seems like a lot but is almost doable with available OPAMP buffers.

---

The next step is to work out heat capacity. I can't find design drawings for the tank itself on the elog/wiki, maybe its too far back in ancient history. There is a solidworks drawing on the SVN but was made in the student version of solidworks so is very buggy.  I will try an extract numbers to get an idea of the mass of metal in the tank. 

Also in progress is a step function measurement of tank cooling.  I spent some of this week working out how to integrate a new RTD acromag card into our existing EPICS setup so we can log the temperature drop after heating is turned off.  This took a while as I was unfamiliar with this kind of setup and also the power supply turned out to be not doing what I thought it was. The voltage current source is now hooked up and a thermister fitted for logging temperature. This measurement should give us some more grounded numbers on the real characteristics of the tank thermal decay rates.

 

 

  1711   Tue Aug 30 10:56:51 2016 AidanSummaryTempCtrlRTDs used in aLIGO TCS RHs

Here's the RH driver PCB for aLIGO:

https://dcc.ligo.org/DocDB/0021/D1002529/006/Driver_RingHeater.pdf

It uses this power amp: https://www.digchip.com/datasheets/download_datasheet.php?id=508953&part-number=LM12CLK

 

Quote:

The heater driver in the old design (iLIGO PSL) is this horrible programmable power supply with high output noise (see measurement of 40m PSL heater).

What we want instead is something that takes in +/- 10 V and drives a DC current (not PWM) into our heaters (which are ~50-100 Ohms). A BUF634 is almost good enough; it can do 200 mA at 10 V. Is there a BUF634 equivalent which can do more like 500 mA? Otherwise we can just use a opamp + transistor.

What is being used for the ring heaters at the LIGO sites?

 

  1712   Wed Aug 31 12:41:30 2016 awadeSummaryTempCtrlHeat load of vacuum can held above room temperature.

The full cool down curve of the tank and a fitted curve (T = A\exp(-t/\tau)+C)are attached below.

Comparison data of temp decay with fitted value (Values below)

 

Least squares fitted values are 

a=23.4145±-0.0005 C, tau=7596±170 s, c=21.00947±0.00004

The variance on the time constant is very large, I think this might be due to a poor fit owing to the fact that the temperature was still rising (rather than steady) when I turned the heating off. We want the whole system to be at equalibrium at the start of the test and we also want a decent tail on the decay. I have therefore repeated the measurment this time heating overnight with 30 V (18 W) which settled on 44.36 C.  I have now left the vac can to cool for the rest of the day (starting about 9.30 am).

Either way it looks like the characteitic 1/e decay time is on the order of 2.1 hours.

Full heat up and cool down, was not quite at equalibrium, but was pretty close. May or may not be an issue. The first blip is due to me changine power supplies halfway through.

 

Attachment 2: plot20160829_RawDateRvsTime.pdf
plot20160829_RawDateRvsTime.pdf
Attachment 3: 20160829plot_TankHeatUpAndStepDown45toRoom-BokehTest.ipynb
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... 303 more lines ...
  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

 

Quote:

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

  • Computer is a Windows machine at 10.0.1.35
  • 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.
  1717   Wed Sep 7 11:20:47 2016 awadeSummaryDAQSome reconfiguring of Acromag crate

Post summarizing some changes and current configuration of the acromag crate.

Some useful previous posts:

I've made a few modifications to the Acromag crate.  There are three cards a XT1221-000 (8 differential inputs) a XT1541-000 (8 DC outputs + 4 digital I/Os) and a  966EN-4006 (Six Channel RTD/resistance).  Up to this time we have been adding channels one by one as we need them. I wanted a few more slow monitor channels so I just went ahead and connected all the rest of the remaining analog input and output channels to finish the job.  I also replaced some of the shorter cabling for the BNC front panel connectors with longer cables so there is a bit more slack inside the crate for these wires.

In time it might be good to put a few LEDs in the front pannels from the binary outputs of the XT1541 card so that we can get a visual blink indicator that some of the perl scripts are running. Alternatively, we can go back to interfacing these with the TTFSS boards as was done in PSL:1573.

A DIN rail mountable power supply (PS5R-SC24) was also fitted inside the rack to replace the variable voltage lab power supply.  This had been a temporary setup. This new power supply provides up to 30 W at 24 V from 110 V AC. The AC in line is strain relieved with a cable tie put through a hole I popped in the side of the crate.

 

Some rearranging of channels:

Previously the PZT/FFS fast controls monitors for the north and south path were inputted through the acromag channels 4 and 5. This was because at the time we only had short BNC cable connector feed throughs.  The order of channels now corresponds the the front panel labeling. The mapping of inputs/outputs+Resistive RTD unit is as follows. The present database file is attached below for reference.

Mapping of Acromag card registers to channels
Acromag card Reference register (address) EPICS Modbus Raw counts channel EPICS-modbus calibrated channel Description/end use of channel
    Hard channel in database (the one that speaks to acromag) Soft channel calibrated to physical units (user friendly channel)  
XT1541-000 (IP=10.0.41) 40002 (0001) C3:ACROMAG_OUTPUT0 C3:PSL-ACAV_FSS_SLOWOUT Output to the slow temperature control of the south cavity laser
  40003 (0002) C3:ACROMAG_OUTPUT1 C3:PSL-RCAV_FSS_SLOWOUT Output to the slow temperature control of the south cavity laser
  40004 (0003) Physically connected by unassigned - Unused
  40005 (0004) Physically connected by unassigned - Unused
  40006 (0005) Unassigned and not connected -  
  40007 (0006) Unassigned and not connected -  
  40008 (0007) Unassigned and not connected -  
  40009 (0008) Unassigned and not connected -  
  10001 (0000) Unassigned and not connected - Unused
  10002 (0001) Unassigned and not connected - Unused
  10003 (0003) Unassigned and not connected - Unused
  10004 (0004) Unassigned and not connected - Unused

XT1221-000

(IP=10.0.0.42)

30001 (0000) C3:ACROMAG_INPUT0 C3:PSL-ACAV_TRANS_ISS_DC South ref cavity transmitted DC signal
  30002 (0001) C3:ACROMAG_INPUT1 C3:PSL-RCAV_TRANS_ISS_DC North ref cavity transmitted DC signal
  30003 (0002) C3:ACROMAG_INPUT2 C3:PSL-TRANS_RF_DC DC signal component of the beat not
  30004 (0003) C3:ACROMAG_INPUT3 C3:PSL-ACAV_FSS_FASTMON Fast monitor output of the south FSS controls (proportional to PZT signal)
  30005 (0004) C3:ACROMAG_INPUT4 C3:PSL-RCAV_FSS_FASTMON Fast monitor output of the north FSS controls (proportional to PZT signal)
  30006 (0005) C3:ACROMAG_INPUT5 C3:PSL-IN-06 General use
  30007 (0006) C3:ACROMAG_INPUT6 C3:PSL-IN-07 General use
  30008 (0007) C3:ACROMAG_INPUT7 C3:PSL-IN-08 General use

966EN-4006

​(IP=10.0.0.43)

30012 (0011)  C3:ACROMAG_TEMP0 (not connected) (resistance calibrated register) C3:ACROMAG_TEMP0  
  30013 (0012) Unassigned and unconnected -  
  30014 (0013) Unassigned and unconnected -  
  30015 (0014) Unassigned and unconnected -  
  30016 (0015) C3:ACROMAG_TEMP4 C3:PSL-VacCanTemp 100 ohm RTD (alpha=), sensor taped directly to the tank for general monitoring.

 

Attachment 1: IOCTEST_BIO_generic.dB.txt
# Database file for PSL lab implemeation of modbus from AcroMag cards
# Last updated: 2016 Sep 02
# By: Andrew Wade

# This file is the master database for the AcroMag cards.  Analog input channels
# are listed first followed by output channels and then temperature/resistance
# channels from the 966EN card. Those channels without a speific use are given
# generic names accociated with the front pannel. 
# Changes since last:
# - More BNC were added to the front pannel and so there was a need to add more
... 346 more lines ...
  1720   Thu Sep 22 11:14:36 2016 awadeSummaryTempCtrlThermal controls: cavity shields and vacuum tank (draft schematic)

I've put together a draft schematic of the basic layout of the shields and tank as well as the present state of connections of the dual ref cavity setup (attached in both pdf and omnigraffle formate).  There are presently no active controls on either the individual cavity shields nor the whole vacuum can. We are relying on passive stability. 

The tank heaters were hooked up to a large current Hewlett Packard 6267B DC power supply.  The unit is no longer producing voltage or current, either a fuse is blown or its kaput; I have removed the unit from the rack. There are a few more 6267Bs around the lab and all have similar problems. I have stacked them all in the corner for assessment and possible disposal in the next big lab cleanup.

Resistive temperature sensors on the two shields are both broken while resistive heating wires on both shields are working. However, according to Tara the length of wire is different because they didn't know at the time if they would be voltage or current limited in their actuation: to mitigate for both cases they chose for the south path to have 85.6Ω resistance and the north 156.8Ω. When we install the new shields we will bring these to be identical. 

I'm not really sure about the existence of a voltage-to-current drivers used in the past.  Its evident that there was one for the previous implementation of PID control of the vacuum can, but I haven't seen any boxes/circuitry in the lab. We need a low noise high current driver for our new implementation. Aidan has linked to the TCS drivers in PSL:1711. Our design requirements will come down to the characteristics of the plant and how it filters the LF noise.

 

Some information we don't have yet:

  • The mass of the tank;
  • the type of temperature sensors used on the current shields;
  • a model of radiative transfer between shields and the tank.  This is significant complicated by the fact that the Al frame and mechanical isolation stages are actually acting as a shield as well (they go all the way around);
  • the schematic of the AD590 -> voltage adaptor circuitry.  The LIGO DCC number appears to be for a VCO servo even though it is labeled "LIGO Temperature Sensor Interface board" a search of the DCC or elog doesn't seem to turn up anything;
  • What current drivers were used in the past to drive the vacuum can heaters
  • Modeling of full impact of end caps? 
  • modeling of improvement from moving to 1" windows on vac can?

 

 

Note: the omnigraffle file has multiple canvases with different info. 

Attachment 1: ThermalControlsDiagram_v8.graffle.zip
Attachment 2: ThermalControlsDiagram_v8.pdf
ThermalControlsDiagram_v8.pdf ThermalControlsDiagram_v8.pdf ThermalControlsDiagram_v8.pdf
  1726   Tue Sep 27 20:54:41 2016 awadeSummaryElectronics EquipmentSettings for Marconi 2023A supplying RF to TTFSS modulators and electronics

Settings for the 14.75 MHz LO and modulator source.  The Marconi doesn't keep memory when turned off for a period of time. This post is general lab documention. 

Marconi 2023A
Carrier Frequency = 14.75 MHz
RF Level = +13 dBm
FM Devn = 0 Hz Off [Off unused]
ModF = 1.0000 kHz [Off unused]

Antonio took attached picture a while ago.  I have also attached a schematic of the present routing of RF to TTFSS boxes and modulators.

See Tara's post PSL:1090 for info on the EOM driver

Attachment 1: TTFFS_RFSupply_Marconi.pdf
TTFFS_RFSupply_Marconi.pdf
Attachment 2: WP_20151007_15_14_35_Pro.jpg
WP_20151007_15_14_35_Pro.jpg
  1728   Thu Sep 29 17:57:32 2016 awadeSummaryTempCtrlHeat load of vacuum can held above room temperature.

The previous cool down test was repeated over a longer time period.  The tank was heated overnight with a 30 V (18 W) (as stated in previous post) and its settling temperature was 44.36±0.05 C. This gives us some idea of the expected DC heat load that the tank will require to maintain an elevated temperature of ~45 C.  

The supply was turned off and a cool down curve was recorded over the next day. Plot is below.  Fitted values were

a = 19.4291±0.0005 C, b=13980±730 s, c=20.75216 ± 0.00003 C

for the fitted equation T(t) = a*\exp(t/b)+c.

With this test (with a longer cool down tail), the time constant for the insulated tank to come to room temperature was 3.88 h

 

 

Quote:

The full cool down curve of the tank and a fitted curve (T = A\exp(-t/\tau)+C)are attached below.

Comparison data of temp decay with fitted value (Values below)

 

Least squares fitted values are 

a=23.4145±-0.0005 C, tau=7596±170 s, c=21.00947±0.00004

The variance on the time constant is very large, I think this might be due to a poor fit owing to the fact that the temperature was still rising (rather than steady) when I turned the heating off. We want the whole system to be at equalibrium at the start of the test and we also want a decent tail on the decay. I have therefore repeated the measurment this time heating overnight with 30 V (18 W) which settled on 44.36 C.  I have now left the vac can to cool for the rest of the day (starting about 9.30 am).

Either way it looks like the characteitic 1/e decay time is on the order of 2.1 hours.

Full heat up and cool down, was not quite at equalibrium, but was pretty close. May or may not be an issue. The first blip is due to me changine power supplies halfway through.

 

 

Attachment 1: 20160830_plot_TankHeatUpAndStepDowntoRoom_30VConst.eps
20160830_plot_TankHeatUpAndStepDowntoRoom_30VConst.eps
Attachment 2: 20160830_VacTankHeatUpAndStepDown45CtoRoom20C_SecondTest.zip
  1737   Wed Oct 5 17:34:57 2016 awadeSummaryTempCtrlSummary parameters of refcav heat shields (parts D1500403 and D1500213)

Summary post pulling together numbers on heat shields.  For future reference.

Drawings and Soildworks files can be found at the following links:

Purchase orders for copper parts: INSERTLINKtowiki
Goldplating specs, vendor and PO: INSERTLINKtowiki

These values were pulled from the SolidWorks files:

Cylindrical heat shield
Property Value
Rough dimensions ø44.45x76.2 mm (wall thickness 1.63 mm)
Mass 72.06 g
Heat capacity  27.75 J/K
Outward facing surface area 100.81 cm^2
Total surface area 201.95 cm^2
Emissivity polished copper 0.04-0.05
Emissivity oxidized copper 0.5-0.8
Emissivity Au (gold) 0.02-0.03

 

End caps of heat shield (per each x2)
Property Value
Rough dimensions (outer face, see drawing for details) face diameter ø44.45; center hole diameter ø12.7 mm
Mass 42.89 g
Heat capacity  16.51 J/K
Outward facing surface area 14.25 cm^2
Total surface area 52.47 cm^2

 

Material properties Cu and Au
Emissivity polished copper 0.04-0.05
Emissivity oxidized copper 0.5-0.8
Emissivity Au (gold) 0.02-0.03
Density 8.96 g/cm3
Thermal conductivity 401 W/(m·K)

 

TOTALS: Properties of heat shield assembly
Property Value
Rough dimensions ø44.45x76.2 mm (wall thickness 1.63 mm)
Mass 157.83 g
Heat capacity  60.76 J/K
Outward facing surface area 205.75 cm^2
Open hole area (end holes and other screw holes) 2.71 cm^2
Radiative cooling time constant/slew rate (for shield @ 45C in 35 C environment) 4.7e-4 K/s
DC heat load kept @ 45C in 35C environment 29 mW
 

 

 

 

*Emissivities drawn from Rathore and Kapuno, Engineering heat transfer, Jones & Bartlett Learning, 2011

 

edit: Mon Oct 10 17:46:40 2016 added DC heat load and radiative cooling slew rate to TOTALS table

 

 

  1742   Mon Oct 10 21:01:52 2016 awadeSummaryTempCtrlRTDs used in aLIGO TCS RHs

Some tests and characteristic noise of the RH drivers: https://dcc.ligo.org/LIGO-E1000785-v1

The documentation  shows noise measurements of ring heater drivers over 0-1.6 kHz span, it would be nice to have have more resolution at LF.  

Key points about the TCS Ring Heater Driver:

  • Conversion 0.08A/V (as is, although this can be adjusted)
  • ~0.07 µA/√Hz @ 100 Hz for 100 mA 
  • ~0.16 µA/√Hz @ 100 Hz for 600 mA

What it does show is increasing noise as the current is increased across the load. It is low compared to expected driving currents for the tank (0.6 A, for 50Ω total load) but maybe note for the shields (~24 mA for refcav shields, for 50Ω heater load).

It doesn't seem to include a characterization of the thermal sensing circuit's noise.

 

Quote:

Here's the RH driver PCB for aLIGO:

https://dcc.ligo.org/DocDB/0021/D1002529/006/Driver_RingHeater.pdf

It uses this power amp: https://www.digchip.com/datasheets/download_datasheet.php?id=508953&part-number=LM12CLK

 

  1743   Tue Oct 11 18:07:59 2016 awadeSummaryDrawingsPSL Lab layout

PDF and omnigraffle file of the PSL lab layout, as of Aug-Oct 2016.

I made this but can't remember posting. Now attached below.

I have updated the graphic outside the lab. This can also be used when the SOP is next updated.

Attachment 1: PSLLabLayout_Aug2016v3.pdf
PSLLabLayout_Aug2016v3.pdf
Attachment 2: PSLLabLayout_Aug2016v3.graffle
  1745   Tue Oct 11 19:46:31 2016 awadeSummaryDocumentationCurrent channels configured in the modbus database

Summary of channels active in the current PSL lab configuration. The .db file is also attached below.

We are almost full for input channels. Also if we wanted to implement an EPICS interface for the FSS control boxes we would need a total of 8 output channels.

 

List of all the current channels:

 
Input Channels
record(calc, "C3:PSL-ACAV_TRANS_ISS_DC") 
record(calc, "C3:PSL-RCAV_TRANS_ISS_DC") 
record(calc, "C3:PSL-BEAT_DC") 
record(calc, "C3:PSL-ACAV_FSS_FASTMON")
record(calc, "C3:PSL-RCAV_FSS_FASTMON")
record(calc, "C3:PSL-ACAV_REFL_DC")  
record(calc, “C3:PSL-RCAV_REFL_DC")  
record(calc, "C3:PSL-VACTEMP_MON1")

 
 

Output channels
record(ai, "C3:PSL-ACAV_FSS_SLOWOUT")
record(ai, "C3:PSL-RCAV_FSS_SLOWOUT")

 

Binary outputs
record(bo, "C3:PSL-ACAV_TEST_EN")
record(bo, "C3:PSL-RCAV_TEST_EN")

 

Temperature channels
record(ai, "C3:ACROMAG_TEMP4")
record(calc, "C3:PSL-VacCanTemp")

 

 

South PID controls soft channels
record(bi, "C3:PSL-ACAV_FSS_SLOWPID_EN")
record(ai, "C3:PSL-ACAV_SLOWFSS_SETPOINT")
record(ai, "C3:PSL-ACAV_FSS_SLOWPID_KP")
record(ai, "C3:PSL-ACAV_FSS_SLOWPID_KI")
record(ai, "C3:PSL-ACAV_FSS_SLOWPID_KD")
record(ai, "C3:PSL-FSS_SLOWPID_TIMEOUT")
record(bo, "C3:PSL-ACAV_FSS_SLOWPID_BLINK")

 

North PID controls soft channels
record(bi, "C3:PSL-RCAV_FSS_SLOWPID_EN")
record(ai, "C3:PSL-RCAV_SLOWFSS_SETPOINT")
record(ai, "C3:PSL-RCAV_FSS_SLOWPID_KP")
record(ai, "C3:PSL-RCAV_FSS_SLOWPID_KI")
record(ai, "C3:PSL-RCAV_FSS_SLOWPID_KD")
record(bo, "C3:PSL-RCAV_FSS_SLOWPID_BLINK")

 
Attachment 1: IOCTEST_BIO_generic.db.zip
  1750   Sun Oct 16 18:01:45 2016 awadeSummaryTempCtrlPlanning thermal controls: some diagrams

Overview schematics of thermal controls' elements and of control loops. These are the basic elements and some numbers.

Basic overview of current temperature shields and layers between lab and refcavs

 

Schematic of expected control loops and key numbers accociated with each element.
Illistration of setup (to scale)

 

Attachment 1: ThermalControlsDiagram_v11_LayersShielding.pdf
ThermalControlsDiagram_v11_LayersShielding.pdf
Attachment 2: ThermalControlsDiagram_v11.pdf
ThermalControlsDiagram_v11.pdf
Attachment 3: ThermalControlsDiagram_v11_moreCTNTankInfo.pdf
ThermalControlsDiagram_v11_moreCTNTankInfo.pdf
Attachment 4: ThermalControlsDiagram_v11.graffle.zip
  1765   Tue Nov 8 14:46:59 2016 awadeSummaryOtherPower cycle in the lab?

Power budget for essentials.

Power budget PSL lab essentials
  Number Power
North + south lasers 2 30 W (max 75 W)
ion Vacuum pump 1

40 W

Acromag1 (computer) 1 200 W (300 W max)
fb2 (computer) 1 300 W
Marconi 2023A 2

70 W (100 W max)

TOTAL  

740 W (990 W max)


 

 

 

 

 

 

 

 

 

APC SMX3000LVNC unit: battery capaciy 738 Volt-Amp-Hour

At the upper bound of consumption (at start of unit life) this will ride out 45 min blackout.

 

 

Quote:

Averaged over the last 10 years, I would say that we have some transient power interruption a couple times per year. Perhaps its worth it to get some kind of UPS?

This one from APC might be good enough to run the lasers and the FB so as to let them ride out a power outage. We mainly want them not to get surges when the Caltech power goes away.

 

 

ELOG V3.1.3-