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ID Date Author Type Categoryup Subject
  16041   Fri Apr 16 11:31:00 2021 ranaUpdateelogelog stuck ~10 AM today

found it unresponsive. Restarted fine using procedure documented in wiki

  8606   Tue May 21 17:03:45 2013 SteveUpdateendtable upgradeenclosure tops are sealed

Quote:

 

 I'm planning to remove the ETMY optical table enclosure and move it over to CES Shop 8am Thursday morning.

We'll install spring loaded lathes, hooks and quick release pins.

The bridge will be reinforced with steel plate to support release pins on posts.

There will be an other cut out for cable feedtrough as it is shown on elog #8472

Let me know if this timing does not fit your work.

 The bridge support posts were shimmed today. Surgical tubing 402R - o - rings were glued togeather with " instant krazy glue "

Atm2  Carey CH-3540 latches are compressed ~2.5 mm in the clamped position.

Atm3 is showing the captured quick release pin in the steel reinforced bridge that is supported by the post. It works great. The post screw is sealed by o-ring. The quick-pin is sealed by an epoxy attached copper cap.

Atm4 Enclosure is on it's back. Bottom o-ring can be seen. The hole reinforced bridge structure is visible.

Now I'm working on the window connection to the chamber. I'm very close leak checking this box.

In case of leaking around the top tubing seals we have two options:

a, cut down on the cover rim by 0.040"  or b, increase tubing diameter

Attachment 1: ETMYoptable.jpg
ETMYoptable.jpg
Attachment 2: surgtubclamps.jpg
surgtubclamps.jpg
Attachment 3: quickrelease.jpg
quickrelease.jpg
Attachment 4: reinforcbridge.jpg
reinforcbridge.jpg
  8628   Thu May 23 12:02:48 2013 SteveUpdateendtable upgradeETMY - oplev

 Temporary oplev in place. The spot on the qpd is still big. My two lens solution did not work.

I will finalize optical component position of the oplev after the the arm transmitted and green beam optics in place. They have priority.

 

Attachment 1: ETMYopl.jpg
ETMYopl.jpg
  8655   Thu May 30 11:10:00 2013 SteveUpdateendtable upgradeETMY - oplev

Quote:

 Temporary oplev in place. The spot on the qpd is still big. My two lens solution did not work.

I will finalize optical component position of the oplev after the the arm transmitted and green beam optics in place. They have priority.

 

 Oplev spot size on qpd ~ 1 mm 

PS: I realized it later that the returning beam is going through a lens for TRY. This is a nono.

      This beam path will be relayed again as the TRY, green beam and IP-ang get there place.

Attachment 1: ETMYoplev.jpg
ETMYoplev.jpg
  8660   Thu May 30 20:45:53 2013 AnnalisaUpdateendtable upgradeETMY - oplev

Quote:

Quote:

 Temporary oplev in place. The spot on the qpd is still big. My two lens solution did not work.

I will finalize optical component position of the oplev after the the arm transmitted and green beam optics in place. They have priority.

 

 Oplev spot size on qpd ~ 1 mm 

PS: I realized it later that the returning beam is going through a lens for TRY. This is a nono.

      This beam path will be relayed again as the TRY, green beam and IP-ang get there place.

 Oplev is disabled. I removed one of the steering mirrors because it was on the green beam  path.

  8662   Fri May 31 11:15:01 2013 AnnalisaUpdateendtable upgradeETMY - Mode Matching for green - new calculation

 Since the beam waist after the Faraday had changed since the last time I measured it (maybe alignment changed a bit), I made a new mode matching calculation for green. I attached the results.

I'm going to align the beam into the Yarm.

RXA: JPG images deleted - replace with PDF please.

  8669   Tue Jun 4 10:44:13 2013 SteveUpdateendtable upgradePI pzt holders are ready

The PI pzt holders are back from the shop. They are numbered 1, 2 & 3 and machined to match.

Tapered black delrin opener is to gauge the gap if it is too small to fit pzt. This is to prevent holder to be opened too much.

Attachment 1: PIpztholders.jpg
PIpztholders.jpg
  8685   Thu Jun 6 09:58:13 2013 SteveUpdateendtable upgradeenclosure to chamber connection

 

 Thin wall connector from McMCarr#55275K25 was tested in 150 mW, 1 mm beam size of 1064 nm  overnight. It did not show any degradation.

Super-Compressible Duct for Air

Hose is made from 0.005" thick, double-ply metalized polyester with a fabric-enclosed steel wire support. 

Atm2, Enclosure viewport adaptor is shown in place of the viewport.

Soft gaskit -   durumeter hardness 10A - McMCarr#9010K51 was added on the 10" od sufaces of conflat and viewport adaptor to insure being air tight.

The duct connector clamped with soft braided elastic " Velstrech" brand loop.

 

Attachment 1: thinwallconnector.jpg
thinwallconnector.jpg
Attachment 2: 06061301.PDF
06061301.PDF 06061301.PDF
  8746   Tue Jun 25 19:18:07 2013 gautamConfigurationendtable upgradeplan of action for PZT installation

  This entry is meant to be a sort of inventory check and a tentative plan-of-action for the installation of the PZT mounted mirrors and associated electronics on the Y-endtable. 

Hardware details:

  •  PZT mounts are cleaned and ready to be put on the end-tables.
  • The PZTs being used are PI S-330.20L Piezo Tip/Tilt Platforms. Each endtable requires two of these. The input channels have male single-lemo connectors. There are 3 channels on each tip/tilt platform, for tilt, yaw and a bias voltage.
  • The driver boards being used are D980323 Rev C. Each board is capable of driving 2 piezo tip/tilt platforms. I am not too sure of this but I think that the SMA female connector on these boards is meant to be connected with the bias voltage from our Kepco high-voltage power supplies. The outputs on these boards are fitted with SMB female connectors, while the piezo tip/tilt platforms have male single-lemo connectors. We will have to source cables with the appropriate connectors to run between the end-table and rack 1Y4 (see below). The input to these boards from the DAC will have to be made with a custom ribbon connector as per the pin out configuration given in the circuit drawing.
  • High-voltage power supply: KEPCO BHK 300-130 MG. This will supply the required 100V DC bias voltage to the piezo tip/tilts via the driver board. Since each board is capable of driving two piezos, we will only need one unit per end-table. The question is where to put these (photo attached). It doesn't look like it can be accommodated in 1Y4 (again photo attached) and the power cable the unit came with is only about 8ft long. If we put these under the end-tables, then we will need an additional long (~10m) cable to run from these to the driver boards at 1Y4 carrying 100 V. 
  •  We will need long (~10m by my rough measurement at the X and Y ends) cables to run from rack 1Y4 to the endtable to drive the piezos. These will have to be high-voltage tolerant (at least to 100V DC) and should have SMB male connectors at one end and female single-lemo connectors at the other. I have emailed 3 firms (CD International Technologies Inc., Stonewall Cables, and Fairview Microwave) detailing our requirements and asking for a quote and estimated time for delivery. We will need 6 of these, plus another cable with an SMA connector on one end and the other end open to connect the 100V DC bias voltage from the high voltage power supply to the driver boards (the power supply comes with a custom jack to which we can solder open leads). We will also possibly need ~3m long lemo-to-?(I need to check what the input connector for the data acquisition channels) cables for the monitoring channels, I am not sure if these are available, I will check with Steve tomorrow.

Other details:

  • I have attached a wiring diagram with the interconnects between various devices at various places and the type of connectors required etc. The error signal will the the transmitted green light from the cavity, and there is already a DQ channel logging this information, so nothing additional wiring is required to this end.
  • Jamie had detailed channel availability in elog 8580. I had a look at rack 1Y4, and there were free DAC channels available, but I am not sure as to which of the ones listed in the elog it corresponds to. In any case, Jamie did mention that there are sufficient channels available at the end-stations for this purposes, but all of these are fast channels. What needs to be decided is if we are going ahead and using the fast channels, or if we need to find slow DAC channels. 
  • I spoke to Koji about gluing the mirrors to the PZTs, and he says we can use superglue, and also to be sure to clean both the mirror and the tip/tilt surfaces before gluing. In any case, all the other hardware issues need to be sorted out first before thinking about gluing the mirrors.

High-Voltage Power Supply

photo_3.JPG

 

Situation at rack 1Y4

 

photo_4.JPG

 Wiring diagram

ASC_schematic.pdf

  8800   Wed Jul 3 21:19:04 2013 gautamConfigurationendtable upgradeplan of action for PZT installation

 This is an update on the situation as far as PZT installation is concerned. I measured the required cable (PZT driver board to PZT) lengths for the X and Y ends as well as the PSL table once again, with the help of a 3m long BNC cable, just to make sure we had the lengths right. The quoted cable lengths include a meter tolerance. The PZTs themselves have cable lengths of 1.5m, though I have assumed that this will be used on the tables themselves. The inventory status is as follows.

  1. Stuff ordered:
    • RG316 LEMO 00 (female) to SMB (female) cables, 10 meters - 6pcs (for the Y-end)
    • RG316 LEMO 00 (female) to SMB (female) cables, 11 meters - 6pcs (for the X-end)
    • RG316 LEMO 00 (female) to SMB (female) cables, 15 meters - 8pcs (6 for the PSL, and two spares)
    • RG316 SMA (male) to open cables, 3 meters - 3pcs (1 each for the X end, Y end and PSL table, for connecting the driver boards to the 100V DC power supply)
    • 10 pin IDC connectors for connecting the DAC interface to the PZT driver boards 
  2. Stuff we have:
    • 40 pin IDC connectors which connect to the DAC interface
    • PZT driver boards
    • PZT mounts
    • Twisted ribbon wire, which will be used to make the custom ribbon to connect the 10 pin IDC to the 40 pin IDC connector

I also did a preliminary check on the driver boards, mainly to check for continuity. Some minor modifications have been made to this board from the schematic shown here (using jumper wires soldered on the top-side of the PCB). I will have to do a more comprehensive check to make sure the board as such is functioning as we expect it to. The plan for this is to first check the board without the high-voltage power supply (using an expansion card to hook it up to a eurocrate). Once it has been verified that the board is getting powered, I will connect the high-voltage supply and a test PZT to the board to do both a check of the board as well as a preliminary calibration of the PZTs.

To this end, I need something to track the spot position as I apply varying voltage to the PZT. QPDs are an option, the alternative being some PSDs I found. The problem with the latter is that the interfaces to the PSD (there are 3) all seem to be damaged (according to the labels on two of them). I tried connecting a PSD to the third interface (OT301 Precision Position Sensing Amplifier), and hooked it up to an oscilloscope. I then shone a laser pointer on the psd, and moved it around a little to see if the signals on the oscilloscope made sense. They didn't on this first try, though this may be because the sensing amplifier is not calibrated. I will try this again. If I can get one of the PSDs to work, mount it on a test optical table and calibrate it. The plan is then to use this PSD to track the position of the reflected beam off a mirror mounted on a PZT (temporarily, using double sided tape) that is driven by feeding small-amplitude signals to the driver board via a function generator. 

 

Misc

The LEMO connector on the PZTs have the part number LEMO.FFS.00, while the male SMB connectors on the board have the part number PE4177 (Pasternack)

Plan of Action:

  • The first task will be to verify that the board is working by the methods outlined above.
  • Once the board has been verified, the next task will be to calibrate a PZT using it. I have to first identify a suitable way of tracking the beam position (QPD or PSD?)
  • I have identified a position in the eurocrate at 1Y4 to install the board, and I have made sure that for this slot, the rear of the eurocrate is not hooked up to the cross-connects. I now need to figure out the exact pin configuration at the DAC interface: the bank is marked 'DAC Channels 9-16' (image attached) but there are 40 pins in the connector, so I need to map these pins to DAC channels, so that when making the custom ribbon, I get the pin-to-pin map right.

DAC_bank.png

 

The wiring scheme has been modified a little, I am uploading an updated one here. In the earlier version, I had mistaken the monitor channels as points from which to log data, while they are really just for debugging. I have also revised the coaxial cable type used (RG316 as opposed to RG174) and the SMB connector (female rather than male).

ASC_schematic.pdf 

 

 

 

 

  8804   Mon Jul 8 13:45:19 2013 gautamConfigurationendtable upgradeDriver board verification

With the help of an expansion card,  I verified that the + 15V and + 24V from the eurocrate in the slot I've identified for the PZT driver boards are making their way to the board. The slot is at the right-most end of the eurocrate in 1Y4, and the rack door was getting in the way of directly measuring these voltages once I hooked up the driver board to the expansion card. So I just made sure that all the LEDs on the expansion card lit up (indicating that the eurocrate is supplying + 5, + 15 and + 24V), and then used a multimeter to check continuity between the expansion card and the driver board outside of the eurocrate. The circuit only uses + 15V and + 24V, and I checked for continuity at all the IC pins marked with these voltages on the schematic.

Since the whole point of this test was to see if the slot I identified was delivering the right voltages, I think this is sufficient. I will now need to fashion a cable that I can use to connect a DC power supply to the PZT driver boards so that these can be tested further.

The high voltage points (100V DC) remain to be tested.

  8823   Wed Jul 10 22:41:06 2013 gautamConfigurationendtable upgradePZT Driver Board

 I did the following with the PZT Driver Board: 

 

  •  With an expansion card attached to the driver board, I used an Agilent E3620A power supply to verify that the 15V and 24V supplies were reaching the intended ICs. It turns out that the +24 V supply was only meant to power some sort of on-board high voltage supply which provided the 100V bias for the PZTs and the MJE15030s. This device does not exist on the board I am using, jumper wires have been hooked up to an SMA connector on the front panel that directly provides 100V from the KEPCO high voltage supply to the appropriate points on the circuit.

  •  All the AD797s as well as the LT1125CS ICs on the board were receiving the required +15V.

      

The next step was to check the board with the high-voltage power supply connected.

 

  •  The output from the power supply is drawn from the rear output terminal strip of the power supply via pins TB1-2 (-OUT) and TB1-7 (+OUT). I used a length of RG58 coaxial cable from the lab and crimped a BNC connector on one end, and stripped the other to attach it to the above pins.

  •  There are several options that can be configured for the power supply. I have left it at the factory default: Local sensing (i.e. operating the power supply using the keypad on the front of it as opposed to remotely), grounding network connected (the outputs of the power supply are floating), slow mode, output isolated from ground.

  • I was unsure of whether the grounding network configuration or the 'positive output, negative terminal grounded' configuration was more appropriate. Koji confirmed that the former was to be used so as to avoid ground loops. When installed eventually, the eurocrate will provide the ground for the entire system.
  • I then verified the output of the HV power supply using a multimeter from 2V up to 150V.
  • I then connected the high voltage supply to the PZT driver board with a BNC-SMA adaptor, set, for a start, to output 30V. Ensured that the appropriate points on the circuit were supplied with 30V.

 

I then hooked up a function generator in order to simulate a control signal from the DAC. The signal was applied to pin 2 of the jumpers marked JP1 through JP4 on the schematic, one at a time. The signal applied was a 0.2 Vpp, 0.1 Hz sine wave.

 

 

 

  •  The output voltage was monitored both using a DMM at the SMB output terminals, and at the monitor channels using an oscilloscope. The outputs at both these points were as expected.
  • There are 4 potentiometers on the board, which need to be tuned such that the control output to the piezos are 50V when the input signal is zero (as this corresponds to no tilt). The gain of the amplifier stage (highlighted in the attached figure) right now is ~15, and I was using 30V in place of 100V, so an input signal of 2V would result in the output saturating. This part of the circuit will have to be tuned once again after applying the full 100V bias voltage. 
  • Koji suggested decreasing the gain of the amplifier stage by switching out resistor R43 (and corresponding resistor in the other 3 stages on the board) after checking the output range of the DAC so that possibility of unwanted saturation is minimised. I need to check this and will change the resistors after confirming the DAC output range. 
  • The potentiometers will have to be tuned after the gain has been adjusted, and with 100V from the high-voltage DC power supply. 

  

To Do:

 

  • Switch out resistors
  • Tune potentiometers with 100V from the HV supply
  • Verify that the output from the board after all the tuning lies in the range 0-100V for all possible input voltages from the DAC.
  • Once the output voltage range has been verified, the next step would be to connect a PZT to the board output, affix a mirror to the tip/tilt, and perform some sort of calibration for the PZT. 

HV_Amplifier.pdf

 

 

 

 

 

 

  8827   Thu Jul 11 09:15:10 2013 SteveUpdateendtable upgradeETMY optable grounded

ETMY optical table top was grounded to the ETMY chamber through 1 Mohms this morning. I  also strain releifed relieved a few cables that were pulling on components directly.

  8845   Mon Jul 15 11:51:18 2013 gautamConfigurationendtable upgradeDAC at 1Y4-Max Output and Power Spectrum

 Summary:

I measured the maximum output of the DAC at 1Y4 as well as its power spectrum. The results are as follows (plots below):

  • Maximum amplitude of differential output: + 10V.
  • Power spectrum has a peak at 64 kHz.

Therefore, the gain of the high-voltage amplification stage on the PZT driver boards do not need to be changed again, as the required output range of 0-100V from the DAC board was realised when the input voltage ranged from -10V to +10 V w.r.t ground. The AI board converts the differential input to a single ended output as required by the driver board.

I will now change some resistors/capacitors on the AI board such that the position of the notches can be moved from 16k and 32k to 64k and 128k.

Procedure:

 Max. amplitude measurement

My previous measurement of the maximum output amplitude of the DAC was flawed as I made the measurement using a single channel of the oscilloscope, which meant that the negative pin of the DAC channel under test was driven to ground. I redid the measurement to avoid this problem. The set up this time was as follows:

  • Positive pin of DAC connected to channel 1 of oscilloscope using break out cable and mini-grabber probe
  • Negative pin of DAC connected to channel 2 of oscilloscope
  • Grounds of channels 1 and 2 connected (I just hooked the mini-grabbers together)
  • Measurement mode on oscilloscope set to channel 1 - channel2
  • Used excitation points set up earlier to output a 3 Hz sine wave with amplitude of 32000 counts from channel 9 of the DAC. 

The trace on the oscilloscope is shown below;

max_amp.JPG

So with reference to ground, the DAC is capable of supplying voltages in the range [-10V 10V]. This next image shows all three traces: positive and negative pins of DAC w.r.t ground, and the difference between the two.

max_amp_all_channels.JPG

 Power spectrum measurement

 

I used the SR785 to make the measurement. The set up was as follows:

  • Positive pin of DAC to A-input of SR560
  • Negative pin of DAC to B-input of SR560
  • A-B output to Channel 1 input A of the SR785
  • SR785 configured to power spectrum measurement

Initially, I output no signal to the DAC, and obtained the following power spectrum. The peak at 65.554 kHz is marked.

DACOffPowerSpec.pdf

I then re-did the measurement with a 200 Hz (left) and 2000 Hz(right), 1000 counts amplitude (I had to change the Ch1 input range on the SR785 from -18dBm to -6dBm) sine wave from channel 9 of the DAC, and obtained the following. The peaks at ~64 kHz are marked.

DACOnPowerSpec.pdf    DAC2kPowerSpectrum.pdf

Now that this peak has been verified, I will work on switching out the appropriate resistors/capacitors on the AI board to move the notches from 16k and 32k to 64k and 128k. 

  8846   Mon Jul 15 13:51:17 2013 KojiConfigurationendtable upgradeDAC at 1Y4-Max Output and Power Spectrum

We need the unit of the voltage power spectrum density to be V/sqrt(Hz).
Otherwise we don't understand anything / any number from the plot.

  8848   Mon Jul 15 15:54:20 2013 gautamConfigurationendtable upgradeDAC at 1Y4- Power Spectrum -with the right units

Quote:

We need the unit of the voltage power spectrum density to be V/sqrt(Hz).
Otherwise we don't understand anything / any number from the plot.

 I redid the measurement with the appropriate units set on the SR785. Power spectral density plots for no output (top), 500Hz, 1000 counts amplitude sine wave (middle) and 2000Hz, 1000 counts amplitude (bottom) are attached, with the right unit on the Y-axis.

 

DACOffPSD.pdf

 

DAC500PSD.pdf

 

DAC2000PSD.pdf

  8852   Mon Jul 15 17:20:43 2013 JenneConfigurationendtable upgradeDAC at 1Y4- Power Spectrum -with the right units

Those 'peaks' for the oscillations seem ridiculously broad.  I think you should look again, really quickly, with smaller bandwidth at, say, the 2kHz oscillation, to make sure it looks reasonable.

  8853   Mon Jul 15 17:59:31 2013 gautamConfigurationendtable upgradeDAC at 1Y4- Power Spectrum -6.4kHz bandwidth

Quote:

Those 'peaks' for the oscillations seem ridiculously broad.  I think you should look again, really quickly, with smaller bandwidth at, say, the 2kHz oscillation, to make sure it looks reasonable.

 I did just this, and it looks okay to me:

DAC-6.4_kHz_BW_PSD.pdf

  8857   Tue Jul 16 14:51:09 2013 gautamConfigurationendtable upgradeAI Board-D000186-Modified notches

 I tried shifting the notch frequencies on the D000186-revision D board given to me by Koji. The existing notches were at ~16 kHz and ~32 kHz. I shifted these to notches at ~64 kHz and ~128 kHz by effecting the following changes (see schematic for component numbering) on Channel 8 of the board-I decided to check things out on one channel before implementing changes en masse:

  • R6 and R7 replaced with 511 ohm smts
  • R8 replaced with 255 ohm smt
  • R14 and R15 replaced with 549 ohm smts
  • R16 replaced with 274 ohm smt

=> New notches should be at 66.3 kHz and 131.7 kHz.

I then measured the frequency response of the modified channel using the SR785, and compared it to the response I had measured before switching out the resistors. The SR785 only goes up to 102 kHz, so I cannot verify the 128 kHz notch at this point. The position of the 64 kHz notch looks alright though. I think I will go ahead and switch out the remaining resistors in the evening.

Note 1: These plots are just raw data from the SR785, I have not tried to do any sort of fitting to poles and zeros. I will do this at some point. 

Note 2: All these smts were taken from Downs. Todd helped me locate the non-standard value resistors. I also got a plastic 25-pin D-sub backshells (the spares are in the rack), with which I have fashioned the required custom ribbon cables (40 pin IDC to 25 pin D-sub with twisted ribbon wire, and a short, 10pin IDC to 10pin IDC with straight ribbon wire).

D000186_Frequency_Response.pdf

  8873   Thu Jul 18 19:09:08 2013 gautamConfigurationendtable upgradeQPD Calibration for PZT Calibration

Summary 

I have been working on setting up a QPD which can eventually be used to calibrate the PZT, and also orient the PZT in the mount such that the pitch and yaw axes roughly coincide with the vertical and horizontal.

The calibration constants have been determined to be:

X-axis: -3.69 V/mm

Y-axis: -3.70V/mm

Methodology:

I initially tried using the QPD setup left behind by Chloe near MC2, but this turned out to be dysfunctional. On opening out the QPD, I found that the internal circuitry had some issues (shorts in the wrong places etc.) Fortunately, Steve was able to hand me another working unit. For future reference, there are a bunch of old QPDs which I assume are functional in the cabinet marked 'Old PDs' along the Y-arm. 

I then made a circuit with which to read out the X and Y coordinates from the QPD. This consists of 4 buffer amplifiers (one for each quadrant), and 3 summing amplifiers (outputs are A+B+C+D = sum, B+C-A-D = Y-coordinate, and A+B-C-D = X-coordinate) that take the appropriate linear combinations of the 4 quadrants to output a voltage that may be calibrated against displacement of the QPD. 

The output from the QPD is via a sub-D connector on the side of the pomona box enclosing the PD and the circuitry, with 7 pins- 3 for power lines, and 4 for the 4 quadrants of the QPD. It was a little tricky to figure the pin-out for this connector, as there was no way to use continuity checking to map the pins to quadrants. Therefore, I used a laser pointer, and some trial and error (i.e. shine the light on a given quadrant, and check the sign of the X and Y voltages on an oscilloscope) to map the pin outs. Steve tells me that these QPDs were made long before colour code standardisation, but I note here the pin outs in any case for future reference (the quadrant orientations are w.r.t the QPD held with all the circuitry above it, with the active surface facing me):

Red= +Vcc

Black= -Vcc

Green = GND

Blue = Upper Left Quadrant

White = Upper Right Quadrant

Purple = Lower Left Quadrant

Grey = Lower Right Quadrant

Chloe had noted that there was some issue with the voltage regulators on her circuit (overheating) but I suspect this may have been due to the faulty internal circuitry. Also, she had used 12 V regulators. I checked the datasheet of the QPD, Op-Amp LF347 (inside the pomona box) and the OP27s on my circuit, and found that they all had absolute maximum ratings above 18V, so I used 15V voltage regulators. The overheating problem was not a problem anymore.

I then proceeded to arrange a set up for the calibration (initially on the optical bench next to MC2, but now relocated to the SP table, and a cart adjacent to it). It consists of the following:

  • He-Ne laser source
  • Y2 2-inch mirror (AR and HR coated for 532nm) glued onto the PZT and mounted on a machined Newport U100P  - see this elog for details.
  • QPD mounted on a translational stage whose micrometers are calibrated in tenths of an inch (in the plots I have scaled this to mm)
  • A neutral density filter (ND = 2.0) which I added so that the QPD amplifier output did not saturate. I considered using a lens as well to reduce the spot size on the QPD but found that after adding the ND filter, it was reasonably small.
  • High-voltage power supply (on cart)
  • Two SR power supplies (for the PZT driver board and my QPD amplifier
  • SR function generator
  • Laser power source
  • Two oscilloscopes
  • Breadboard holding my QPD amplifier circuit

Having set everything up and having done the coarse alignment using the mirror mount, I proceeded to calibrate the X and Y axes of the QPD using the translational stage. The steps I followed were:

  • Centre spot on QPD using coarse adjustment on the mirror mount: I gauged this by monitoring the X and Y voltage outputs on an oscilloscope, and adjusted things till both these went to zero.
  • Used the tilt knob on the translational stage to roughly decouple the X and Y motion of the QPD.
  • Kept Y-coordinate fixed, took the X-coordinate to close to its maximum value (I gauged this by checking where the voltage stopped changing appreciably for changes in the QPD position.
  • Using this as a starting point, I moved the QPD through its X range, noting voltage output of the X-coordinate (and also the Y) on an oscilloscope.
  • Repeated the procedure for the Y-coordinate.
  • Analysis follows largely what was done in these elogs. I am attaching the script I used to fit an error function to the datapoints, this is something MATLAB should seriously include in cftool (note that it is VERY sensitive to the initial guess. I had to do quite a bit of guessing).

The plots are attached, from which the calibration values cited above are deduced. The linear fits for the orthogonal axis were done using cftool. There is some residual coupling between the X and Y motions of the QPD, but I think this os okay my purposes. 

My next step would be to first tweak the orientation of the PZT in the mount while applying a small excitation to it in order to decouple the pitch and yaw motion as best as possible. Once this is done, I can go ahead and calibrate the angular motion of the PZT in mrad/V.

 

                                                            X-Axis                                                                                                                                Y-axis                                                

QPD-XCalib.pdf  QPD-YCalib.pdf

 

 

Attachment 3: Error_Function_Fitting.zip
  8874   Thu Jul 18 20:20:52 2013 gautamConfigurationendtable upgradeFirst mirror glued to PZT and mounted in modified mounts

 

 Yesterday, I mounted the first PZT in one of the modified mounts, and then glued a 2-inch Y2 mirror on it using superglue.

Details:

-The mirror is a 2-inch, Y2 mirror with HR and AR coatings for 532 nm light.

-The AR side of the mirror had someone's fingerprint on it, which I removed (under Manasa's guidance) using tweezers wrapped in lens cleaning paper, and methanol.

-Before gluing the mirror, I had to assemble the modified mount. Manasa handed over the remaining parts of the mounts (which are now in my newly acquired tupperware box along with all the other Piezo-related hardware). I took the one labelled A, and assembled the holder part. I then used one of the new mounts (2.5 inches, these are with the clean mounts in a cardboard box in the cupboard holding the green optics along the Y-arm) and mounted the holder on it. 

-Having assembled the mount, I inserted the piezo tip-tilt into the holder. The wedge that the machine shop supplied is useful (indeed required) for this. 

-I then cleaned the AR surface of the mirror and the top-surface of the tip-tilt. 

-The gluing was done using superglue which Steve got from the bookstore (the remaining tube is in the small fridge). We may glue the other mirror using epoxy. I placed 4 small drops of superglue on the tip-tilt's top surface, placed the mirror with its AR face in contact with the piezo, and applied some pressure for a short while until the glue spread out fairly evenly. I then left the whole setup to dry for about half an hour.

-Steve suggested using a reference piece (I used two small bolts) to verify when the glue had dried.

-Finally, I attached the whole assembly to a base.

Here it is in action in my calibration setup (note that it has not been oriented yet. i.e. the two perpendicular axes of the piezo are for the time being arbitrarily oriented. And maybe the spreading of the glue wasn't that even after all...):

Piezo-mirror.jpg

 

Sidenote:

Yesterday, while setting stuff up, I tested the piezo with a 0.05 Hz, 10Vpp input from the SR function generator just to see if it works, and also to verify that I had set up all my electronics correctly. Though the QPD was at this point calibrated, I did observe periodic motion of both the X and Y outputs of my QPD amp! Next step- calibration... 

  8875   Thu Jul 18 21:12:58 2013 gautamConfigurationendtable upgradeAI Board-D000186-All channels modified

 

 I carried some further modifications and tests to the AI Board. Details and observations here:

  • I switched out the resistors for all the remaining 7 channels, using the same substitutions as detailed here
  • I then verified that the modified transfer function for all 8 channels using the SR785. I did not collect data for all the channels as netgpib was taking ages, but I did use the cursor on the screen to verify the position of the first notch at ~64 kHz. I noticed that all the channels did not have the lowest point of the notch at the same frequency. Rather, (at least on the screen), this varied between 63kHz and 67kHz. I would put this down to component tolerance. Assuming 5% tolerance shifts the theoretical notch frequency from 66268 Hz to 63112 Hz. 
  • After verifying the transfer functions, I went to 1Y4 and plugged the AI board into the eurocrate. I then connected the input of the AI board to the DAC output using my custom ribbon cable. Next, I used the excitation points set up earlier to send a 1 kHz, 32000 counts amplitude sine wave through the channels one at a time. I monitored the output using an oscilloscope and the LEMO monitor channels on the front panel of the board.
  • I found that the single-ended output of the AI board swings between -10 V and 10 V (w.r.t ground, oscilloscope trace attached). This is good because this is the range of input voltage to the PZT driver boards required to realize the full actuation range of the PZTs.
  • I also verified that the connections on the custom ribbon cable are correct (channel map was right) and that there were no accidental shorts (I checked other channels' output monitor while driving one channel). 

I think the board is okay to be used now.

AI_Board_Output.jpg

 

  8877   Thu Jul 18 23:34:40 2013 gautamConfigurationendtable upgradeCoarse adjustment of PZT axes orientation in mount

 I have managed to orient the PZT in the mount such that its axes are approximately aligned with the vertical and the horizontal. 

In the process, I discovered that the 4 screws on the back face of the PZT correspond to the location of the piezoelectric stacks beneath the tip-tilt platform. The PZT can therefore be oriented during the mounting process itself, before the mirror is glued onto the tip-tilt platform.

In order to verify that the pitch and yaw motion of the mirror have indeed been roughly decoupled, I centred the spot on the QPD, fed to the 'pitch' input of the PZT driver board (connected to channel 1 of the PZT) a 10 Vpp, 1 Hz sine wave from the SR function generator (having turned all the other relevant electronics, HV power supply etc ON. The oscilloscope trace of the output observed on the QPD is shown. The residual fluctuation in the Y-coordinate (blue trace) is I believe due to the tilt in the QPD, and also due to the fact that the PZT isnt perfectly oriented in the mount.

It looks like moving the tip-tilt through its full range of motion takes us outside the linear regime of the QPD calibration. I may have to rethink the calibration setup to keep the spot on the QPD in the linear range if the full range is to be calibrated, possibly decrease the distance between the mirror and the QPD. Also, in the current orientation, CH1 on the PZT controls YAW motion, while CH2 controls pitch.

Oscilloscope Trace:

Yellow: X-coordinate

Blue: Y-coordinate

PZT_out_waveform.jpg

  8883   Fri Jul 19 22:51:40 2013 gautamConfigurationendtable upgradeSecond mirror glued to PZT and mounted

 

I mounted the second PZT in a modified mount, and then glued a 1-inch Y2 mirror on it using superglue.

 Details:

-The mirror is a Laseroptik 1-inch, Y2 mirror with HR and AR coatings for 532 nm light.

-The procedure for mounting the mirror was the same as detailed in elog 8874. This time, I tried to orient the Piezo such that the four screws on the back face coincided with the horizontal and vertical axes, as this appeared to (somewhat) decouple the pitch and yaw motion of the tip-tilt on the first PZT.

-One thing I forgot to mention in the earlier elog: it is best to assemble the mount fully before inserting the tip-tilt into it and gluing the mirror to the tip-tilt. In particular, the stand should be screwed onto the mount before inserting the tip-tilt into the holder, as once it is in, it will block the hole through which one can screw the stand onto the mount. 

-I have placed the mirror on the SP table along with the rest of my QPD/Piezo calibration setup. I will attempt to calibrate this second PZT once I am done with the first one. 
 
Here is an image of the assembly:
Piezo-mirror_2.JPG

 

 

 

 

 

 

 

  8884   Fri Jul 19 23:35:31 2013 gautamConfigurationendtable upgradePreliminary Calibration of PZT

 I recalibrated the QPD today as I had shifted its position a little. I then identified the linear range of the QPD and performed a preliminary calibration of the Piezo tip-tilt within this range.

 


Details:

-I recalibrated the QPD as I had shifted it around a little in order to see if I could move it to a position such that I could get the full dynamic range of the piezo tilt within the linear regime of the QPD. This proved difficult because there are two reflections from the mirror (seeing as it is AR coated for 532nm and I am using a red laser). At a larger separation, these diverge and the stray spot does not bother me. But it does become a problem when I move the QPD closer to the mirror (in an effort to cut down the range in which the spot on the QPD moves). In any case, I had moved the QPD till it was practically touching the mirror, and even then, could not get the spot motion over the full range of the PZTs motion to stay within the QPD's linear regime (as verified by applying a 20Vpp 1Hz sine wave to the PZT driver board and looking at the X and Y outputs from the QPD amplifier. 

-So I reverted to a configuration in which the QPD was ~40cm away from the mirror (measured using a measuring tape).

-The new calibration constants are as follows (see attached plots):

X-Coordinate: -3.43 V/mm
Y-Coordinate: -3.41 V/mm


-I then determined the linear range of the QPD to be when the output was in the range [-0.5V 0.5V]. 

-Next, at Jenne's suggestion, I decided to do a preliminary calibration of the PZT within this linear range. I used an SR function generator to supply an input voltage to the PZT driver board's input (connected to Channel 1 of the piezo). In order to supply a DC voltage, I set a DC offset, and set the signal amplitude to 0V. I then noted the X and Y-coordinate outputs, being sure to run through the input voltages in a cyclic fashion as one would expect some hysteresis. 

-I did this for both the pitch and yaw inputs, but have only superficially analysed the latter case (I will put up results for the former later). 

 


Comments:

-There is indeed some hysteresis, though the tilt seems to vary linearly with the input voltage. I have not yet included a calibration constant as I wish to perform this calibration over the entire dynamic range of the PZT. 

 

-There is some residual coupling between the pitch and yaw motion of the tip tilt, possibly due to its imperfect orientation in the holder (I have yet to account for the QPD's tilt).

 

-I have not included a graphical representation here, but there is significantly more pitch to yaw coupling when my input signal is applied to the tip-tilts pitch input (Channel 2), as compared to when it is input to channel 1. It is not clear to me why this is so.

 

-I have to think of some smart way of calibrating the PZT over its entire range of motion, keeping the spot in the QPD's linear regime throughout. One idea is to start at one extreme (say with input voltage -10V), and then perform the calibration, re-centering the spot to 0 on the QPD each time the QPD amp output reaches the end of its linear regime. I am not sure if this will work, but it is worth a shot. The other option is to replace the red laser with a green laser (from one of the laser pointers) in the hope that multiple reflections will be avoided from the mirror. Then I will have to recalibrate the set up, and see if I can get the QPD close enough to the mirror such that the spot stays within the linear regime of the QPD. More investigation needs to be done.


Plots:

QPD Calibration Plots:
QPD-XCalib.pdf            QPD-YCalib.pdf

 

 

Piezo tilt vs input voltage plots:

 

                                                          Yaw Tilt                                                                                                                                         Pitch Tilt

Piezo_Yaw_Calib-in_QPD_linear_range-Yaw_tilt.pdf               Piezo_Yaw_Calib-in_QPD_linear_range-Pitch_tilt.pdf 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  8892   Mon Jul 22 17:17:30 2013 annalisaUpdateendtable upgradeEnd table picture
Attachment 1: YendTable.jpg
YendTable.jpg
  8896   Tue Jul 23 00:51:46 2013 KojiUpdateendtable upgradeEnd table picture

The spot on the IPANG QPD was checked. The spot is higher than the center and South side of the lens.
Some photos are found below.

The spot on the IPANG steering mirrors in the ETMY chamber was also checked.
It is clipped at the top of the steering mirror. (See attachment 4)
So basically the spot is about 1" above the center of the mirror.

Attachment 1: P7224222.JPG
P7224222.JPG
Attachment 2: P7224223.JPG
P7224223.JPG
Attachment 3: P7224224.JPG
P7224224.JPG
Attachment 4: P7224238.JPG
P7224238.JPG
  8910   Tue Jul 23 19:37:08 2013 AnnalisaUpdateendtable upgradeEnd table picture

Quote:

The spot on the IPANG QPD was checked. The spot is higher than the center and South side of the lens.
Some photos are found below.

The spot on the IPANG steering mirrors in the ETMY chamber was also checked.
It is clipped at the top of the steering mirror. (See attachment 4)
So basically the spot is about 1" above the center of the mirror.

 After the vent, the IPang spot position on the steering mirrors on the Yend table moved approximately by 1 inch down.

Inside the chamber, the spot position is in the center of the steering mirror. (difficult to take a picture because the PSL beam power has been reduced)

Attachment 1: IMG950073.jpg
IMG950073.jpg
Attachment 2: IMG950072.jpg
IMG950072.jpg
  8912   Tue Jul 23 20:41:40 2013 gautamConfigurationendtable upgradeFull range calibration and installation of PZT-mounted mirrors

 Given that the green beam is to be used as the reference during the vent, it was decided to first test the PZT mounted mirrors at the X-endtable rather than the Y-endtable as originally planned. Yesterday, I prepared a second PZT mounted mirror, completed the full range calibration, and with Manasa, installed the mirrors on the X-endtable as mentioned in this elog. The calibration constants have been determined to be (see attached plots for aproximate range of actuation):

M1-pitch: 0.1106 mrad/V

M1-yaw: 0.143 mrad/V

M2-pitch: 0.197 mrad/V

M2-yaw: 0.27 mrad/V


Second 2-inch mirror glued to tip-tilt and mounted:

  • The spot sizes on the steering mirrors at the X-end are fairly large, and so two 2-inch steering mirrors were required.
  • The mirrors already glued to the PZTs were a CVI 2-inch and a Laseroptik 1-inch mirror.
  • I prepared another Laseroptik 2-inch mirror (45 degree with HR and AR coatings for 532 nm) and glued it to a PZT mounted in a modified mount as before.
  • Another important point regarding mounting the PZTs: there are two perforated rings (see attached picture) that run around the PZT about 1cm below the surface on which the mirror is to be glued. The PZT has to be pushed in through the mount till these are clear of the mount, or the actuation will not be as desired. In the first CVI 2-inch mirror, this was not the the case, which probably explains the unexpectedly large pitch-yaw coupling that was observed during the calibration [Thanks Manasa for pointing this out]. 

Full range calibration of PZT:

Having prepared the two steering mirrors, I calibrated them for the full range of input voltages, to get a rough idea of whether the tilt varied linearly and also the range of actuation. 

Methodology:

  • The QPD setup described in my previous elogs was used for this calibration. 
  • The linear range of the QPD was gauged to be while the output voltage lay between -0.5V and 0.5V. The calibration constants are as determined during the QPD calibration, details of which are here.
  • In order to keep the spot always in the linear range of the QPD, I stared with an input signal of -10V or +10V (ie. one extreme), and moved both the X and Y micrometers on the translational stage till both these coordinates were at one end of the linear range (i.e -0.5V or 0.5V). I then increased the input voltage in steps of ~1V through the full range from -10V to +10V DC. The signal was applied using a SR function generator with the signal amplitude kept to 0, and a DC offset in the range -5V to 5V DC, which gave the desired input voltages to the PZT driver board (between -10V DC and 10V DC).
  • When the output of the QPD amp reached the end of the linear regime (i.e 0.5V or -0.5V), I moved the appropriate micrometer dial on the translational stage to take it to the other end of the linear range, before continuing with the measurements. The distance moved was noted. 
  • Both the X and Y coordinates were noted in order to investigate pitch-yaw coupling.

Analysis and remarks:

  • The results of the calibration are presented in the plots below. 
  • Though the measurement technique was crude (and maybe flawed because of a possible z-displacement while moving the translational stage), the calibration was meant to be rough, and I think the results obtained are satisfactory. 
  • Fitting the data linearly is only an approximation, as there is evidence of hysteresis. Also, PZTs appear to have some drift, though I have not been able to quantify this (I did observe that the output of the QPD amp shifted by an amount equal to ~0.05mm while I left the setup standing for an hour or so).  
  • The range of actuation seems to be different for the two PZTs, and also for each degree of freedom, though the measured data is consistent with the minimum range given in the datasheet (3.5 mrad for input voltages in the range -20V to 120V DC). 

 

PZT Calibration Plots

The circles are datapoints for the degree of freedom to which the input is applied, while the 'x's are for the other degree of freedom. Different colours correspond to data measured with the position of the translational stage at some value.

                                            M1 Pitch                                                                                             M1 Yaw

M1_Pitch_calib.pdf     M1_Yaw_calib.pdf

 

                                              M2 Pitch                                                                                        M2 Yaw 

M2_Pitch_calib.pdf     M2_Yaw_calib.pdf

 



Installation of the mirrors at the X-endtable:

The calibrated mirrors were taken to the X-endtable for installation. The steering mirrors in place were swapped out for the PZT mounted pair. Manasa managed (after considerable tweaking) to mode-match the green beam to the cavity with the new steering mirror configuration. In order to fine tune the alignment, Koji moved ITMx and ETMx in pitch and yaw so as to maximise green TRX. We then got an idea of which way the input pointing had to be moved in order to maximise the green transmission.

 

Attachment 5: PI_S330.20L.pdf
PI_S330.20L.pdf
  8930   Sun Jul 28 19:39:04 2013 AnnalisaUpdateendtable upgradePicture

 Yend table picture updated on the wiki page

  8932   Mon Jul 29 13:39:25 2013 gautamConfigurationendtable upgradePZT Driver Board-further changes

 

 

I have updated the schematic of the D980323 PZT driver boards to reflect the changes made. The following changes were made (highlighted in red on the schematic):

  • Gain of all four HV amplifier stages changed from ~15 to ~5 by swapping 158k resistors R43, R44, R69 and R70 for 51k resistors.
  • Electrolytic 10 uF capacitors C11, C12, C29 and C31 swapped for 470pF, 500V mica capacitors.
  • Fixed resistor in voltage divider (R35, R40, R59 and R64) replaced with 0 ohm resistors so as to be able to apply a bias of -10V to the HV amplifier
  • The DC-DC Series components, which I think were originally meant to provide the 100V DC voltage, have been removed.
  • The path between the point at which +100V DC is delivered and jumpers J3 and J6 has been shorted (bypassing R71 and R11 for J3, R73 and R12 for J6).
  • Tantalum capacitors C38 and C39 have been replaced with electrolytic capacitors (47 uF, 25V). One of the original tantalum capacitors had burned out when I tried installing the board in the eurocrate, shorting out -15V to ground. At Koji's suggestion, I made this switch. The AD797s do not seem to be oscillating after the switch.


I have also changed the routing of the 100V from the HV power supply onto the board, it is now done using an SMA T-connector and two short lengths of RG58 cable with SMA connectors crimped on.

The boards are functional (output swings between 0 and 100V as verified with a multimeter for input voltages in the range -10V to +10V applied using a function generator.

 



Revised schematics:

D980323-C-modified.pdf

D980323-C-modified-pg2.pdf

 

 

 

  8935   Mon Jul 29 21:57:45 2013 gautamConfigurationendtable upgradeHardware installed at 1X9

 The following hardware has been installed on rack 1X9;

  • KEPCO high voltage power supply (kept in a plastic box at the bottom of the rack, with the 3m SMA cable carrying 100V running along the inside side wall of the rack). The HV supply has not been connected to the driver board yet.
  • AI board D000186 installed in top eurocrate. The board does not seem to fit snugly into the slot, so I used a longish screw to bolt the front panel to the eurocrate.
  • PZT driver board D980323 installed in top eurocrate adjacent to the AI board.
  • Six 11m SMB-LEMO cables have been laid out from 1X9 to the endtable. I have connected these to the PZT driver board, but the other end (to the PZTs) is left unconnected for now. They have been routed through the top of the rack, and along the cable tray to the endtable. All the cables have been labelled at both ends. 


I have also verified that the AI board is functional in the eurocrate by using the LEMO monitoring points on the front panel.


The driver boards remain to be verified, but this cannot be done until we connect the HV supply to the board. 

 

 

  8942   Tue Jul 30 19:40:47 2013 gautamConfigurationendtable upgradeDAC-PZT Driver Board Output Signal Chain Tested

 

 [Alex, Gautam]

The signal chain from the DAC output to the output of the PZT driver board (including the HV supply) has been verified. 

I had installed the two boards in the eurocrate yesterday and laid out the cables from 1X9 to the endtable. The output of the AI board had been verified using the monitor port on the front panel, but the output from the PZT driver board was yet to be checked because I had not connected the HV supply yesterday.

When I tried this initially today, I was not getting the expected output from the monitor channels on the front panel of the PZT driver board, even though the board was verified to be working. Alex helped debug the problem, which was identified as the -15V supply voltage not making it onto the board.

I changed the slot the board was sitting in, and used a long screw to bolt the board to the crate. Both the AI board and the PZT driver board seem to be slightly odd-sized, and hence, will not work unless firmly pushed into the eurocrate and bolted down. This would be the first thing to check if a problem is detected with this system. 

In any case, I have bolted both boards to the eurocrate, and the output from the PZT driver board is as expected when I sent a 10Vp sine wave out from the DAC. I think the cables can now be hooked up to the PZTs once we are pumped down.

  8943   Tue Jul 30 19:44:05 2013 gautamConfigurationendtable upgradeSecond mirror glued to PZT and mounted

 

 I have glued a fourth mirror to a PZT (using superglue) and inserted it into a modified mount. This is to be used together with the 1-inch Laseroptik mirror I had glued a couple of weeks back at the Y-endtable. I will be calibrating both these mirrors tonight such that these are ready to put in as soon as we are pumped down.

The mirror was one of those removed from the X-endtable during the switch of the steering mirrors. It is a CVI 2-inch mirror, with HR and AR coatings for 532 nm. 

  8967   Mon Aug 5 18:48:44 2013 gautamConfigurationendtable upgradeFull range calibration of PZT mounted mirrors for Y-endtable

 I had prepared two more PZT mounted mirrors for the Y-end some time back. These are:

  • A 2-inch CVI mirror (45 degree, HR and AR for 532nm, was originally one of the steering mirrors at the X-endtable, and was removed while switching those out for the PZT mounted mirrrors).
  • A 1-inch Laseroptik mirror (45 degree, HR and AR for 532nm).

I used the same QPD set-up and the methodology described here to do a full-range calibration of these PZTs. Plots attached. The calibration constants have been determined to be:

CVI-pitch: 0.316 mrad/V

CVI-yaw:  0.4018 mrad/V

Laseroptik pitch: 0.2447 mrad/V

Laseroptik yaw:  0.2822 mrad/V

Remarks:

  • These PZTs, like their X-end counterparts, showed evidence of drift and hysteresis. We just have to deal with this.
  • One of the PZTs (the one on which the CVI mirror is mounted) is a used one. While testing it, I thought that its behaviour was a little anomalous, but the plots do not seem to suggest that anything is amiss.

Plots:

                                                        CVI YAW                                                                                                                         CVI PITCH

2-inch-CVI-Yawcalib.pdf      2-inch-CVI-Pitchcalib.pdf

                                                        Laseroptik YAW                                                                                                             Laseroptik PITCH

1-inch-Laseroptik-Yawcalib.pdf   1-inch-Laseroptik-Pitchcalib.pdf

 

  9451   Mon Dec 9 11:44:08 2013 SteveUpdateendtable upgradeETMY optable got new beam dump

Aluminum shield replaced by razor beam dump.

Attachment 1: ETMYoptBefore.jpg
ETMYoptBefore.jpg
Attachment 2: ETMYoptAfter.jpg
ETMYoptAfter.jpg
  9941   Mon May 12 14:42:25 2014 steveUpdateendtable upgradeoptical table enclosure wall proposal and table at ETMY

Quote:

 Sanwiched wall as shown: 1" clear acrylic, 2 layers of 0.004" thick "window tint", 1 layer of  0.007" thermashield  and  0.125" yellow acrylic

Visibility: 70 %,    Transmission of 1064 nm  2-3 % at 0-50 degrees incident,   power density  ~ 0.7 W/mm2

Max power 100 mW

        

More details about this east end  " acrylic + "   enclosure ( optical table cover ) can be found elog entry 6210, 7194 and  7106

 

Window tinted layer transmission plot is below.

 

We have a film which may meet your requirements and the values are shown below:

         

               Wavelength (nm)              Transmission                     Reflectance(front)            Reflectance (back)

 

                        1060                               .0772                               .604                                     .759

 

                        1070                               .0723                               .615                                     .772

 

These values are taken from the LBNL Optics 6 program and if you have access to that program, the NFRC ID for the film is 202.   If you do not have access to the program, I have a captured the graph which may be of some help.  I apologize for the appearance of the graph but someone at LBNL decided it would look better with a dark gray background – the yellow is the transmission curve, the blue is the reflectance (front) and the green is the reflectance (back).

 

 

The film is referred to as “Hilite 70” and has a 72% visible light transmission.  These results were obtained with the film mounted on 1/8” clear glass.

 

I

 

 

 

 

 

Saint-Gobain Performance Plastics

www.solargard.com

 

Please consider your environmental responsibility before printing this email.

 

 

 

Attachment 1: Hilite70.jpg
Hilite70.jpg
Attachment 2: ETMY-ISCT.jpg
ETMY-ISCT.jpg
Attachment 3: RoscoThermashield.pdf
RoscoThermashield.pdf
  11591   Fri Sep 11 10:56:47 2015 SteveUpdateendtable upgradeETMY optical table feedthrough

The ETMY enclosure feedthrough - north is installed. The sealing material is hard to work with.

The upper empty blocks will be replaced by something soft to make changing cables easy.

 

Attachment 1: ETMY-Nfeedt.jpg
ETMY-Nfeedt.jpg
  11600   Tue Sep 15 16:49:08 2015 SteveUpdateendtable upgradeETMY optical table feedthrough

ETMY optical table enclosure feedthrough- south is in. Now it is time to see how air tightness increases performance.

Quote:

The ETMY enclosure feedthrough - north is installed. The sealing material is hard to work with.

The upper empty blocks will be replaced by something soft to make changing cables easy.

 

 

Attachment 1: ETMYsFeedt.jpg
ETMYsFeedt.jpg
  11608   Thu Sep 17 02:22:53 2015 SteveUpdateendtable upgradeETMY optical table feedthrough

I doubt we'll see any effect until we carefully seal the holes. If there's 1 hole in your boat it still sinks.

Quote:

ETMY optical table enclosure feedthrough- south is in. Now it is time to see how air tightness increases performance.

 

  11897   Tue Dec 22 16:39:42 2015 SteveUpdateendtable upgradeETMY optical table enclosure

I think there should be a scientifically based aveluation of the ETMY enclosure so we can make the ETMX better.

Meanwhile I'm counting pieces to move on with the south end table cover.

 

Attachment 1: IMG_0028.JPG
IMG_0028.JPG
Attachment 2: IMG_0027.JPG
IMG_0027.JPG
Attachment 3: ETMY-ISCT_EISOL.jpg
ETMY-ISCT_EISOL.jpg
  12029   Thu Mar 10 16:29:32 2016 gautamUpdateendtable upgradeInventory check

I did a quick sweep of the lab to find out what hardware has already been acquired for the X-end table upgrade. The attached PDF is an inventory check in the spirit of this elog.

Some things we have to decide:

  • Are we okay with using the old green coloured faraday mount for the IR faraday? I have in hand a piece identical to the one used at the Y-end for the green faraday, that is red in colour, so I guess we can switch this out.
  • The way in which the doubling oven is currently mounted at the X-end is using some posts cobbled together. The Y-end looks to have a custom mount machined for it (see Attachment #2). Do we want to go ahead and get something like this done?
  • I suppose it is okay to reuse all the old optics (mirrors, lenses, harmonic separators) and PDs? It may be that we need to order som extra mirrors/lenses/posts (this will become clear once I do the layout)

I have not gotten around to planning the layout or doing drawings. I will try and first work through a mode-matching solution to make sure we have all the required lenses. It may be that we need some 1" or 2" mirrors as well. The beam from the lightwave NPRO is quite elliptical, but we have a number of cylindrical lenses in hand already if we decide we want to use these, so I guess we don't have to worry about this...

This is quite a preliminary list, and I will add/update over the coming days as I do more detailed planning, but have I missed out anything obvious?

Attachment 1: Inventory_check.pdf
Inventory_check.pdf
Attachment 2: Doubler_comparison.pdf
Doubler_comparison.pdf
  12030   Thu Mar 10 16:32:45 2016 ranaUpdateendtable upgradeInventory check

Its not a good idea to use green mounts with green lasers. Steve should be able to get another copy of the EY doubler mount made up if we really don't have another one sitting in the Manasa end table box which Koji mentioned.

  12033   Mon Mar 14 22:42:23 2016 gautamUpdateendtable upgradeInventory check
Quote:

Steve should be able to get another copy of the EY doubler mount made up if we really don't have another one sitting in the Manasa end table box which Koji mentioned.

I located the second doubler mount, it was sitting inside a cabinet along the Y-arm. So this will not have to be machined. The doubling oven mount is black in colour.

So as things stand now, the only thing that needs to be machined is a non-green mount for the IR faraday (IO-5-1064-HP) - is it possible to just coat the existing mount with a different color? I've got a drawing for this part ready, but it seems unnecessary to machine the whole thing from scratch when only the color is an issue. Steve was talking about dipping this in some sort of solution and taking the green off. But if this isn't possible, I'll send Steve the drawings tomorrow so that he can place the order with the machine shop...

I will work on the mode-matching calculations over the next couple of days to make sure we have all the mirrors and lenses we need.

 

  12051   Mon Mar 28 10:43:18 2016 SteveUpdateendtable upgradeETMX 4'x2' optical table pictures

 

 

Attachment 1: ETMX4x2Layout.jpg
ETMX4x2Layout.jpg
Attachment 2: ETMX_4x2.JPG
ETMX_4x2.JPG
Attachment 3: ETMXopt_4x2.JPG
ETMXopt_4x2.JPG
  12056   Wed Mar 30 17:38:52 2016 gautamUpdateendtable upgradeX end table proposed layout

Attachment 1: This is a photo of the current X end table optical layout with the beampaths of the various sub-systems overlaid. For the labels, see Attachment #2.

Attachment 2: This is a summary of all the optical components that are currently being used. I've noted some things we may want to change when we effect the swap. The important ones are:

  • Switch out all 1" and 2" optic mounts which are not of the Polaris type to the Polaris type. I have checked that we have sufficient numbers of these in hand.
  • Adjust the collimating lens of the fiber collimating telescope to get a better mode
  • Many of the labels are probably outdated, now would be a good time to update them
  • For the mode-matching of the AUX IR into the doubling crystal, a la mode suggests a better (i.e. less sensitive to lens position) solution is effected with L2 as a 100mm fl lens rather than 88.3mm. I did not change this during the laser swap in order to minimize the number of components changed. Since we are doing a wholesale change now, it may not be a bad idea to swap this out as well. I have checked that we have a suitable AR1064 coated lens.
  • Some optics probably need to be cleaned...
  • PZT mirror 2 has a new mount ready that is the "correct" height so we don't have to keep using makeshift stacked posts.
  • The plan as it stands is to use the green coloured mount for the IR faraday (IO-5-1064-HP).

Have I missed anything important?

Attachment #3: I've made a CAD drawing of the proposed new layout and have overlaid the beampath in an amateur way because I couldn't figure OptoCad out - I figure this will suffice for now. I have adopted elements from the current Y-end layout, but have used Anders' mode-matching solution (same lenses, same positions of optics) to make sure we have good Guoy phase separation between the two PZT steering mirrors. Some notes:

  • I've tried to palce the optics for the AUX IR into the doubler and subsequent steering of green into the arm cavity as per the mode matching solution. These should be pretty accurate, and the layout suggests we have some room to maneuver 
  • The Green REFL beampath is exaggerated but I think we have enough room to place Y16 appropriately and steer the reflected beam into the PDA36A
  • We need two more 1" 1064nm coated mirrors for the initial steering into the doubling oven, I have checked we have these in hand.
  • The IR pickoff into the fiber coupler may change somewhat once we change the mode and redo the mode-matching calculations. But again, I think we have sufficient room to implement a workable solution.
  • After accounting for the fact that the new endtable will be a little closer to the vacuum chamber, Y12 in the proposed layout will be ~10cm further away from ETMX than it is currently. But as discussed at the meeting today, the Rayleigh range of the green beam should be large enough here such that this shouldn't be a significant change.

Steve says the table is ready - so if we are happy with this layout, we can move forward...

Attachment 1: ETMX_3x2.JPG
ETMX_3x2.JPG
Attachment 2: layout_details_20160328.pdf
layout_details_20160328.pdf
Attachment 3: ETMX_proposed_layout.pdf
ETMX_proposed_layout.pdf
  12057   Thu Mar 31 09:38:41 2016 SteveUpdateendtable upgradeY end 4x3 existing layout

Beam colors: 1064 nm red, 514 nm green and 633 nm yellow.

There should be room for lens in front of the pd at red3 and a mirror for alignment in the new layout.

This picture may help you how to improve the new ETMX 4' x 3' optical layout.

 

Attachment 1: ETMY4x3layout.jpg
ETMY4x3layout.jpg
  12058   Thu Mar 31 19:49:31 2016 gautamUpdateendtable upgradeproposed layout v2

The major changes from the previous layout:

  1. I've depicted the Green reflected beam path more accurately - I approximately measured the angle of the rejected beam from the faraday from the Y-end setup. This looks like a workable solution, and is similar to what we have currently at the Y-end
  2. I've added some optics to monitor the DC power and RIN of the AUX laser
  3. I've added two lenses to the input path of the Oplev beam (the path is such that I think we can use the same lenses that are currently being used. 
  4. I've now drawn the beams in CAD so that is marginally neater.

To do:

  1. Post mode matching solutions for AUX laser to doubler and green beam to arm for this proposed layout (should be identical to what we have now, which at least according to the calculation is a good solution, but I will double check - I also need to quantify what the effect of the elliptical beam is)
  2. Check the Gouy phase of the transmitted IR beam at the QPD - we may need to change some lenses in this path. But I think the path as such is close enough (distance-wise) to what we have currently at the X end (after accounting for the fact that the new endtable edge will be closer to the ETM) so I don't expect this to be a show-stopper.

Does any part of this layout need a radical redesign? 

Attachment 1: ETMX_proposed_layout_v2.pdf
ETMX_proposed_layout_v2.pdf
  12060   Mon Apr 4 10:59:12 2016 gautamUpdateendtable upgradeproposed layout v3

I realized I had overlooked an important constraint in the layout, which is that the enclosure will have two supports that occupy some region of the table - these are denoted in blue in v3 of the layout (Attachment #1). I measured the dimensions for these from the existing Y-endtable. The main subsystem this has affected is the IR transmission monitors, but I've been able to move the photodiodes a little to accommodate this constraint.

I've also done the mode-matching calculations explicitly for the proposed new layout (Attachments #2 and #3, code in Attachment #4). While the layout was largely adopted from what Andres posted in this elog, I found that some of the parameters he used in his a la mode code were probably incorrect (e.g. distance between the 750mm lens and the ETM). More critically, I think the Gouy phase for the optimized solution in the same elog is more like 60 degrees. I found that I could get a (calculated) Gouy phase difference between the two PZT mirrors of ~81 degrees by changing the green path slightly, and making the two PZT mirrors Y7 and Y8 (instead of Y7 and Y11, for which the Gouy phase difference is more like 50 degrees). But this way the two steering mirrors are much closer to each other than they were before. Other misc. remarks about the mode matching calculations:

  • The beam diameter at the locations where the Faraday isolators should go is well below 5mm, the aperture size of the Faraday isolators
  • The calculated mode-matching efficiencies suggest that we don't need any cylindrical lenses though the mode from the NPRO is elliptical
  • Attachment #5 is a CAD drawing of the layout with all dimensions used for the mode-matching calculations included (although they are in inches)

These changes also necessitated minor changes to the transmitted IR beampath and the Oplev system, but these changes are minor. I've also switched the positions of the AUX IR power monitoring PD and the fiber coupler as suggested by Koji. The shutter has also been included. 

Attachment 1: ETMX_proposed_layout_v3.pdf
ETMX_proposed_layout_v3.pdf
Attachment 2: IR_modematch.pdf
IR_modematch.pdf
Attachment 3: Green_modematch.pdf
Green_modematch.pdf
Attachment 4: XendALaMode.zip
Attachment 5: ETMX_proposed_layout_dimensions.dwg
  12061   Mon Apr 4 15:04:14 2016 gautamUpdateendtable upgradeCOMPONENT REMOVAL


I'm planning to start removing components from the X endtable tomorrow morning at ~10AM - if anyone thinks I should hold off and do some further checks/planning, let me know before this so that I can do the needful.

ELOG V3.1.3-