I have made a prototype circuit of the triple resonant EOM.

The attached is the measured optical response of the system.

The measured gains at the resonances are 8.6, 0.6 and 7.7 for 11MHz, 29.5MHz and 55MHz respectively.

I successfully got nice peaks at 11MHz and 55MHz. In addition resultant optical response is well matched with the predicted curve from the measured impedance.

However there is a difference from calculated response (see past entry) (i.e. more gains were expected)

Especially for the resonance of 29.5MHz, it was calculated to have gain of 10, however it's now 0.6. Therefore there must a big loss electrically around 29.5MHz.

I am going to re-analyze the impedance and model the performance in order to see what is going on.

Hey, this looks nice, but can you provide us the comparison of rad/V with the resonant EOM of New Focus?

The commercial resonant EOM of New Focus has the modulation efficiency of 50-150mrad/Vrms. ( This number is only true for those EOM made from KTP such as model4063 and model4463 )

Our triple-resonant EOM (made from KTP as well) has a 90mrad/Vrms and 80mrad/Vrms at the reosonances of 11MHz and 55MHz respectively.

Therefore our EOM is as good as those of company-made so that we can establish a new EOM company

(RF reflections)

The reflected RF power going back to the RF generation box will be :

    Power at 11MHz =  2 dBm

   Power at 29.5 MHz = 3 dBm

   Power at 55 MHz = 9dBm

Assuming the input power at 11 and 55 MHz are at 27 dBm (40m wiki page). And 15 dBm for 29.5 MHz.

Since there is an RF combiner in between the generation box and the resonant box, it reduces the reflections by an additional factor of 10 dB (#4517)

In the estimation above, the reduction due to the RF combiner was taken into account.

(Modulation depths)

Besides the reflection issue, the circuit meets a rough requirement of 200 mrad at 11 and 55 MHz.

For the 29.5 MHz modulation, the depth will be reduced approximately by a factor of 2, which I don't think it's a significant issue.

So the modulation depths should be okay.

Assuming the performance of the resonant circuit remains the same (#2586), the modulation depths will be :

      Mod. depth at 11 MHz =  280 mrad

      Mod. depth at 29.5 MHz = 4 mrad (This is about half of the current modulation depth)

      Mod. depth at 55 MHz = 250 mrad

The triple resonant box was checked again. Each resonant frequency was tuned and the box is ready to go.

Before the actual installation I want to hear opinions about RF reflections because the RF reflection at 29 MHz isn't negligible.

It might be a problem since the reflection will go back to the RF generation box and would damage the amplifiers.

(Frequency adjustment and resultant reflection coefficient)

In order to tune the resonant frequencies the RF reflection was continuously monitored while the variable inductors were tweaked.

The plot below shows the reflection coefficient of the box after the frequency adjustment. 

In the upper plot, where the amplitude of the reflection coefficient of the box is plotted, there are three notches at 11, 29.5 and 55 MHz.

A notch means an RF power, which is applied to the resonant box, is successfully absorbed and consequently the EOM obtains some voltage at this frequency.

These power absorptions take place at the resonant frequencies as we designed so.

A good thing by monitoring this reflection coefficient is that one can easily tune the resonant frequency by looking at the positions of the notches.

Note that :

If amplitude is  0dB ( =1),  it means all of the signal is reflected.

If a circuit under test is impedance matched to 50 Ohm the amplitude will be ideally zero (= -infinity dB).

Reflections :

at 11 MHz = -15 dB (3% of RF power is reflected)

at 29.5 MHz = -2 dB (63% of RF power is reflected)

at 55 MHz = -8 dB (15% of RF power is reflected)

What are the reflected RF powers for those frequencies? 
Is the 29.5MHz more problem than the 55MHz, considering the required modulation depth?

The first design of the triple resonant EOM circuit has been done.

If only EOM has a loss of 4 Ohm, the gain of the circuit is expected to be 11 at 55MHz

So far I've worked on investigation of the single resonant circuit and accumulated the knowledge about resonant circuits.

Then I started the next step, designing the triple resonant circuit.

Here I report the first design of the circuit and the expected gain.

( What I did )

At first in order to determine the parameters, such as inductors and capacitors, I have solved some equations with numerical ways (see the past entry).

In the calculation I put 6 boundary conditions as followers;

(first peak=11MHz, second peak=29.5MHz, third peak=55MHz, first valley=22MHz, second valley=33MHz, Cp=18pF)

The valley frequencies of 22MHz and 33MHz are chosen in order to eliminate the higher harmonics of 11MHz, and Cp of 18pF represents the capacitance of the EOM.

Basically the number of parameters to be determined is 6 ( L1, L2, ...,), therefore it is completely solved under 6 boundary conditions. And in this case, only one solution exists.

The point is calculation does not include losses because the loss does not change the resonant frequency.

( results )

As a result I obtained the 6 parameters for each components shown in the table below.

Then I inserted the loss into the EOM to see how the impedance looks like. The loss is 4 Ohm and inserted in series to the EOM. This number is based on the past measurement .

Let us recall that the gain of the impedance-matched circuit with a transformer is proportional to square-root of the peak impedance.

It is represented by G = sqrt(Zres/50) where Zres is the impedance at the resonance.

 As you can see in the figure, Zres = 6.4 kOhm at 55MHz, therefore the gain will be G=11 at 55MHz.

Essentially this gain is the same as that of the single resonant circuit that I've been worked with, because its performance was also limited mainly by the EOM loss.

 An interesting thing is that all three peaks are exactly on the EOM limited line (black dash line), which is represented by Zres = L/CR = 1/ (2pi f Cp)^2 R. Where R = 4 Ohm.

( next plan )

There are other solutions to create the same peaks and valleys because of the similar solution.

 It is easy to understand if you put Cp' = Cp x N, the solutions must be scaled like L1'=L1/N, C1'=C1 x N, ...,  Finally such scaling gives the same resonant frequencies.

So the next plan is to study the effect of losses in each components while changing the similar solution.

After the study of the loss I will select an optimum similar solution.

Very cool.         

The design looks very good. I have some questions.

1. As far as I remember, you've got the gain of slightly worse than 10 for a 55MHz single resonant case. Why your expectation of the gain (G=11) for the highest resonance better than this?

Supposing the loss exists only on the EOM, the other part of the LC network for the triple work as an inductor at the resonant frequency. This is just equivalent as the single resonant case. So the expected gain at 55MHz should coincides with what we already have. Probably, the resistance of 4 Ohm that is used here had too rough precision???

2. How can you adjust the resonances precisely?

Do we need any variable components for Cs and Ls, that may have worse quality than the fixed one, generally speaking.
I myself has no experience that I had to tune the commercial EOM because of a drift or whatever. I hope if you can adjust the resonance with a fixed component it should be fine.

3. Changing Cp. What does it mean?

Do you put additional cap for Cp?

4. The resonances for the lower two look very narrow. Is that fine?

This will show up in a better shape if we look at the transfer function for the gain. Is this right?

If we have BW>100kHz, it is sufficient.

5. Impedance matching for the lower two resonances.

Yep. You know this problem already.

Self-follow:

I got the answer of Q3 from the follow-up entry.

For Q4, once you get the impedance of the LC network lower than n^2*50, the EOM gain will be quite low. This means that the resonance is anyway narrow.
I did some simple calculation and it shows that the width of the resonance will be 100kHz~500kHz. So it maybe OK.

Bertine Robby, Bertin and Jerry completed the installation by pouring concrete yesterday and cleaning up today.

Atm1-2, steel bars, grouted feet and side forms are ready

Atm3,    bounding agent is applied for better bounding

Atm4,    pumping concrete

Atm5,    shaker is used to fill-all

Atm6,    late after noon the forms- sides were removed,     NOTE: actual table to concrete distance is 12.75"

Atm7,    construction people left and the tile man is on the way

The tile patching should complete today so tomorrow we can remove plastic covers.

Pete, Yoichi

Last night, we put the IFO in FP Michelson configuration.  We took transfer functions of CARM and DARM, first using CM excitations directly on the ETMs, and then using modulations of the laser frequency via MC excitation.  We found that there was basically no coupling into DARM using the MC excitation, but that there was coherence in DARM using the ETM excitation.  Therefore, I tuned the ETM common mode in the output matrix.  I did this by taking transfer functions of PD1_Q with PD2_I (see attached plot).  I changed the  drdown_bang script to set C1:LSC-BTMTRX_14 0.98 and C1:LSC-BTMTRX_24 1.02.

Gautam and Steve,

Spare Varian turbo-V 70 controller, Model 969-9505, sn 21612 was swapped in. It is running the turbo fine @ 50Krpm but it does not allow it's V4 valve to be opened............

It turns out that TP2 @ 75Krpm will allow V4 to open and close. This must be a software issue.

So Vacuum Normal is operational if TP2 is running 75,000 rpm

We want to run at 50,000 rpm on the long term.

Note: the RS232 Dsub connector on the back of this controller is mounted 180 degrees opposite than TP3  and old failed TP2 controller

PS: controller is shipping out for repair 7-28-2017

[Steve / Kiwamu]

 As a part of the video cable session, we reconnected some power cords on 1Y1 rack.

During the work we momentarily turned off c1aux, which handles DMF, Illumintators, mechanical shutters and the old video epics.

I think it automatically reverted the things, but we may need to check them.

In the lab there are lots of old posters with outdated autocad drawings, or printouts with schematics of old electronics hanging on the walls.

Can we get rid of those and start giving the lab a fresh and modern look?

[Koji, Jamie]

We tweaked up the alignment of the half PRC a bit.  Koji started by looking at the REFL and POP DC powers as a function of TT2 and PRM alignment. 
He found that the reflected beam for good PRC transmission was not well overlapped at REFL.  When the beam was well overlapped at REFL, there was clipping in the REFL path on the AS table.

We started by getting good overlap at REFL, and then went to the AS table to tweak up all the beams on the REFL pds and cameras.
This made the unlocked REFL DC about 40 count. This was about 10mV (=0.2mA) at the REFL55 PD.
This amazed Koji since we found the REFL DC (of the day) of 160 as the maximum of the day for a particular combination of the PRM Pitch and TT2 Pitch. So something wrong could be somewhere.

We then moved to the ITMX table where we cleaned up the POP path.  We noticed that the lens in the POP path is a little slow, so the beam is too big on the POP PD and on the POP camera (and on the camera pick-off mirror as well). 
We moved the currently unused POP55 and POP22/110 RFPDs out of the way so we could move the POP RF PD and camera back closer to the focus.  Things are better, but we still need to get a better focus, particularly on the POP PD.

We found two irides on the oplev path. They are too big and one of these is too close to the POP beam. Since it does not make sense too to have two irides in vicinity, we pulled out that one from the post.

Other things we noticed:

• The POP beam is definitely clipping in the vacuum, looks like on two sides.
• We can probably get better layout on the POP table, so we're not hitting mirrors at oblique angles and can get beams on grid paths.

After the alignment work on the tables, we started locking the cavity. We already saw the improvement of the POPDC power from 1000 cnt to 2500 cnt without any realignment.
Once PRM is tweaked a little (0.01ish for pitch and yaw), the maximum POPDC of 6000 was achieved. But still the POP camera shows non-gaussian shape of the beam and the Faraday camera shows bright
scattering of the beam. It seems that the scattering at the Faraday is not from the main beam but the halo leaking from the cavity (i.e. unlocking of the cavity made the scattering disappeared)

Tomorrow Jenne and I will go into BS to tweak the alignment of the TEMP PRC flat mirror, and into ITMX to see if we can clean up the POP path.

Now some pedestals, mirrors and lenses are left on the PSL table, since we are on the middle way to construct a PLL setup which employs two NPROs instead of use of PSL laser.

So Please Don't steal any of them.

 Can I please get the network analyzer back?

[Yaakov, Eric, Jenne, Yuta]

Two of our surfs, Yaakov and Eric, pulled two unused RG-405/SMA cables that had been running from 1X2 to (mysteriously) 1Y2 racks.  They left the 1X2 end where it was and pulled the 1Y2 end and rerouted it to the control room.  We labeled both ends appropriately.

The end at 1X2 is now plugged into a splitter that is combining the RF input monitor outputs for the X and Y beatbox channels, so that we can watch the beat signals with the HP8591 in the control room.

According to the measurement done by Aidan and me, there are two beat-note state.

One gave us a small beat signal and the other gave us a bigger signal by approximately 20 dB.

 A possible reason for this phenomenon is that the end laser is operating at a special temperature that somehow drives the laser with two different modes at the same time.

So that it permits the laser sometimes locked with one of the two modes and sometimes with the other mode.

For the first step we will change the temperature such that the laser can run with a single stable mode.

Then for investigating it we will put a scanning cavity on the X end table to see if it really exhibits a two modes or not.

 Quick post of plots and data; I'll fill in more detail tonight. 

TL;DR: I pulled both green PDH boxes and made LISO models, compared TFs and noise levels. 

Pictures of X and Y boards, respectively

TF comparison to LISO. (Normalized to coincide at 1Hz)

Noise comparison to LISO

To Do:

• Figure out why TFs were made differently. Check PM response curves of PZTs to see if they are fine, or need tweaking.
• Make boosts useful. Both are currently integrators with corners under 10Hz, which is already pretty suppressed. 
• I just noticed that the X board is missing C25, which should be a 1uF cap on the positive power pin of the primary TF stage opamp. This should be inserted. 

All data, EAGLE schematics, LISO source and plots in the attached zip. 

I had noticed in the past, that the digital control signal monitor for the X end would saturate well before the ADC should saturate (C1:ALS-X_SLOW_SERVO_IN1, which is from the "output mon" BNC on the box). It turns out that there is some odd saturation happening inside the box itself.

In this scope trace, the servo input is being driven with a 0.02Vpp, 0.1Hz sine wave, gain knob at 1.0. This is bad. 

Evan and I poked around the board, and discover that for some reason currently unknown to us, the variable gain amplifier (AD8336) can't reach its negative rail, despite the +-12V arriving safely at its power supply pins. 

I also realized that the LF356 in the integrator stage in this box had been replaced with a LT1792 by Kiwamu in ELOG 4373. I've updated my schematic, and will upload both boxes' schematics to the DCC page Jenne created for them. (D1400293 and D1400294)

 I've been having trouble locking the X - green for the past few hours. Has there been some configuration change down there that anyone knows about?

I'm thinking that perhaps I need to replace the SHG crystal or perhaps remove the PZT alignment mirrors perhaps. Another possibility is that the NPRO down there is going bad. I'll start swapping the Y-end NPRO for the X-end one and see if that makes things better.

I had pulled out both X and Y servo boxes for inspection, put the Y box back, soldered in a missing op amp power capacitor on the X end box, and had not yet put back the X end box yet because of the saturation issue I was looking into. Otherwise nothing was changed at the ends; I didn't open the tables at all, or touch laser/SHG settings, just unplugged the servo boxes. 

I narrowed down the saturation point in the X green PDH box to the preamp inside the AD8336, but there is still no clear answer as to why it's happening. 

As per Jenne's request, I put the X end PDH box back for tonight's work. It locks, but we have an artificially low actuation range. With SR785, I confirmed a PDH UGF around 5k. Higher than that, and I couldn't reliably measure the UGF due to SR560 saturations. The analyzer is not currently in the loop. 

Both arms lock to green, but I haven't looked at beatnotes today. 

What monitor point is being plotted here? Or is it a scope probe output?

If this saturation is in the uPDH-X but not in the uPDH-Y, then just replace the VGA chip. Because these things have fixed attenuation inside, they often can't go the rails even when the chip is new.

In any case, we need to make a fix to get this box on the air in a fixed state before tomorrow evening.

The traces were from the front panel output BNCs, but the VGA preamp exhibited this asymmetric saturation at its output.  

In any case, I tried to replace the Xend box's AD8336 with a new one, and in doing so, did some irreparable damage to the traces on the board  I was not able to get a new AD8336 into the board. There are some ATF ELOGs where Zach found the AD8336 noise to be bad at low frequencies (link), and its form factor is totally unsuitable for any design that may involve hand modification, since it doesn't even have legs, just tiny little pads. I suggest we never use it for anything in the future. 

Instead, I've hacked on a little daughter board with an OP27 as an inverting op-amp with the gain resistor on the front panel as its feedback resistor, which can swing from 0 to x20 gain (the old gain setting was around 15dB=~x6). I've checked out the TF and output noise, and they look ok. The board can output both rails as well. 

I don't really like this as a long term solution, but I didn't want to leave things in a totally broken state when I left for dinner. 

I installed awgstream-2.16.14 in /ligo/apps/ubuntu12.  As with all the ubuntu12 "packages", you need to source the ubuntu12 ligoapps environment script:

controls@pianosa|~ > . /ligo/apps/ubuntu12/ligoapps-user-env.sh
controls@pianosa|~ > which awgstream
/ligo/apps/ubuntu12/awgstream-2.16.14/bin/awgstream
controls@pianosa|~ > 

I tested it on the SRM LSC filter bank.  In one terminal I opened the following camonitor on C1:SUS-SRM_LSC_OUTMON.  In another terminal I ran the following:

controls@pianosa|~ > seq 0 .1 16384  | awgstream C1:SUS-SRM_LSC_EXC 16384 -
Channel = C1:SUS-SRM_LSC_EXC
File    = -
Scale   =          1.000000
Start   = 1092790384.000000
controls@pianosa|~ > 

The camonitor output was:

controls@pianosa|~ > camonitor C1:SUS-SRM_LSC_OUTMON
C1:SUS-SRM_LSC_OUTMON          2014-08-22 17:44:50.997418 0  
C1:SUS-SRM_LSC_OUTMON          2014-08-22 17:52:49.155525 218.8  
C1:SUS-SRM_LSC_OUTMON          2014-08-22 17:52:49.393404 628.4  
C1:SUS-SRM_LSC_OUTMON          2014-08-22 17:52:49.629822 935.6  
...
C1:SUS-SRM_LSC_OUTMON          2014-08-22 17:52:58.210810 15066.8  
C1:SUS-SRM_LSC_OUTMON          2014-08-22 17:52:58.489501 15476.4  
C1:SUS-SRM_LSC_OUTMON          2014-08-22 17:52:58.747095 15886  
C1:SUS-SRM_LSC_OUTMON          2014-08-22 17:52:59.011415 0 

In other words, it seems to work.

Rana wanted the latest GDS installed (for newest DTT), so I made an ubuntu 12 install directory into which I installed

• gds-2.16.3.2
• root_v5.34.03

I installed this stuff in

/ligo/apps/ubuntu12

which is the "official" location for stuff compiled specifically for ubuntu12.

Given that the workstations are diverging in OS (some ubuntu10, some ubuntu12), we're going to have to start supporting different software packages for the different versions, thus the new ubuntu12 directory.  This will be a pain in the butt, and will certainly lead to different versions of things for different machines, different features, etc.  We should really try to keep things at the same OS.

In any event, if you want to enable the GDS on an ubuntu 12 machine, source the ubuntu12 ligoapps-user-env.sh file:

controls@ottavia|~ > . /ligo/apps/ubuntu12/ligoapps-user-env.sh

Last week Rana and I struggled to figure out how to un-full-screen windows on the Ubuntu workstations that appeared to be stuck in some sort of full screen mode such that the "Titlebar" was not on the screen.  Nothing seemed to work.  We were in despair.

Well, there is now hope: it appears that this really is a "fullscreen" mode that can be activated by hitting F11.  It can therefore easily be undone by hitting F11 again.

Today I tried some things, but basically, lowering the input gain by 10 made the thing stable. In the attached screenshotstrip, you can see what happens with the gain at 1. After a few cycles of oscillation, I turned the gain back to 0.1.

There still is an uncontrolled DoF, but I that's just the way it is since we only have one mirror (the BS) to steer into the x arm once the yarm pointing is fixed.

Along the way, I also changed the phase for POX, just in case that was an issue. I changed it from +86 to +101 deg. The attached spectra shows how that lowered the POX_Q noise.

I also changed the frequencies for ETM_P/Y dither from ~14/18 Hz to 11.31/14.13 Hz. This seemed to make no difference, but since the TR and PO signals were quieter there I left it like that.

This is probably OK for now and we can tune up the matrix by measuring some sensing matrix stuff again later.

Thank you both.

I have updated the .snap file, so that it'll use these parameters, as Rana left them.  Also, so that the "unfreeze" script works without changes (since it wants to make the overall gain 1), I have changed the Xarm input matrix elements from 1 to 0.1, for all of them.  This should be equivalent to the overall gain being 0.1.

 I'm working on similar shelf at ETMY.  Precondition: NPRO in bypass mode, heater for doubling in bypass........since power outage?  Optical level servo turned off.......

U-channel based shelf in place.  Oplev servo is back on at 11:15am    The table may moved.  The oplev return is missing the quad by a few milimeter.

I added an U channel based bottom shelf at the south end today.

We were stymied early in the evening by a surreptitiously placed, verbo-visually obfuscated command in the drstep script. 

IFO pressure 2 Torr,    PSL  shutter closed.  I'm pumping down with 2 roughing pumps with ion pump gate valves open and annulosses at atm.

The vacuum envelope was vented to 17 Torr while I was replacing the USP battery stack. More about this later.....

Do not plan on using the interferrometer tonight.  I will complete the pumpdown tomorrow morning.

Pumpdown stopped for over night  at ~  1 Torr

The roughing line disconnected.  Valves condition indicator  "moving " means that it is closed and it's cable disconnected so it can not move.

The RGA is off and VM1 is stuck.

pd80b has reached Vac Normal. IFO pressure 0.5 mTorr

We need our vauum channels back in dataviewer.

Jamie reported that:

The logs (/var/log/daemon.log) on fb1 are filling with this line:

Jan 03 14:11:51 fb1 dhcpd[1152]: DHCPDISCOVER from 3c:ec:ef:c8:44:78 via enp3s0: network 10.0.113.0/24: no free leases

It seems that some machine on the network is trying to get an IP address but can't

• The MAC address 3c:ec:ef:xx:xx:xx indicates this is one of the supermicro units.
• The IP address indicates this is on the DAQ network which fb1 is spanning.
• There is a switch for this DAQ network. 
• There are 8 machines connected to the switch. fb1 is via optical, and the other 7 have yellow ethernet cables (Attachment 1).
• fb1 and other 6 RT machines already have 10.0.113.x assigned.
• The rest is c1shimmer. I can't ssh into it from martian. KVM on rack 1X7 shows a black screen assuming 1-7 is c1shimmer. I wonder what's the status of this machine, but left untouched so far.

The dhcpd error on the log file stopped when the yellow (DAQ) ethernet cable was removed. With Chris's permission I left it unconnected (Attachment 1).

Chris pinted that the IPMI on c1shimmer is supposed to be exposed to 192.168.113. net rather than DAQ net.

From dhcpd.conf on chiara:

host c1shimmer-ipmi {
  hardware ethernet 3c:ec:ef:c8:44:78;
  fixed-address 192.168.113.37;
}

So the ethernet connections of c1shimmer is still questionable. The next person to work with c1shimmer needs to check them.

This would also be related?
https://lanforge.wordpress.com/2015/11/10/turning-off-ipmi-dhcp/

fb has been loading a 'symmetricom' kernel module, presumably because it was once being used to help with timing.  It's no longer needed, so I unloaded it and commented out the lines that loaded it in /etc/conf.d/local.start.

It seems that the MC3 problem is intermittent (one-day trend attached).  I tried to take advantage of a "clean MC3" night, but the watch script would usually fail at the transition to DC CARM and DARM.  It got past this twice and then failed later, during powering up.   I need to check the handoff.

Moved the unstick.py code to the ifotest repository here. It now handles signals like those generated by Ctrl-C and so forth. It can still be run as python unstick.py <machine1> <machine2> etc.

I cleaned up the south Electronics bench today.

The other two, as well as several of the desks are in some chaotic state of degradation. Please clean up your areas and put away projects which do not need to remain staged for several months. Try to eliminate "that's not mine" and "I don't know who's that is" from your vocabulary.  Fight back against entropy!

Sometimes ago I reported that there have been a kind of upconversion noise when PRM was excited (#6211).

This time I found another one, which showed up when BS was excited.

Assuming this is related to some kind of scattering process and also assuming this is from the same scattering body as that for the PRM driven case,

we may be able to localize and perhaps identify the scattering body.

(Measurement Condition)

(Noise spectrum)

Over the last couple nights we got the beam into the FSS path and all the way to the IMC and out onto the AP table.

Tara and Valera have calculated a mode-matching solution for the reference cavity. It utilizes only a single lens between the AOM and the reference cavity. Valera and Steve will move the reference cavity into place in the morning.

We noticed that the layout was too tight on the end going into the MC and so we adjusted the angle of the final zig-zag. This will put the final mode-matching lens in between the final steering mirrors (which is generally undesirable) but the lens in this case is only f=400 mm. In addition, this lens may provide some more decoupling between the steering mirrors.

The whole layout has to be a little adjusted because of a calculation mistake I made in the mode-matching. I used only the nominal focal lengths from the CVI catalog and not the effective one. For the UV-grade fused silica lenses, the effective focal length is actually 20-30% longer. Today we measured that the "f=200 mm" lens we got is actually f = 238 mm. The BK7 lenses are much closer to the nominal.

We also replaced the Klinger mount ahead of the PMC with a Polanski style so that we could get the PMC REFL beam out without hitting the mount. Valera will continue to refine this section on the weekend.

Tomorrow, we will lock the MC using feedback only to the NPRO. The 0-150 V piezo driver is on the PSL table ready for action.

I also got a LCD video monitor from Frank and hooked it up on the PSL table. If we like this kind of thing, we can get many of them. They are pretty cheap. It would be handy to have 3-4 of them on the PSL and one on every of the ISC tables. They take the standard video for input and need +12V for power. Right now the one in there is looking at the PMC transmission.

The Omnigraffle layout as of tonight is attached.

I put some green stuff on the layout drawing.

I continue to refine the positions of these stuff.

Notes :

 1. I flipped the reference cavity. So now the cavity is sitting on the left hand side of the layout.

  2. I removed the ISS stuf. We should think about where ISS should be.

I tried SRMI. The glitch rate wasn't as high as that of PRMI but it happened once per 10 sec or so.