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ID Date Author Type Category Subjectup
  313   Sat Jan 12 22:49:11 2019 KojiOpticsCharacterizationPM-SM patch cable mode cleaning effect

Mode cleaning capability of an optical fiber was measured. The conclusion is that the leakage of the non-fiber mode to the fiber output is insignificant and also practically negligible.

The tested fiber was Thorlabs 5-m Polarization Maintaining Single-Mode fiber (P3-1064PM-FC-5, PM Patch Cable, PANDA, 1064 nm, FC/APC, 5m).

The output mode cleaner was used as a mode analyzer. The fiber input was aligned and the misaligned so that the amount of higher order mode for the fiber is changed. The fiber output has been mode matched to an output mode cleaner. Therefore excess mode mismatch when the fiber input was misaligned, was accounted as the leakage higher order mode.

For each alignment state, the OMC transmission (in V), the OMC reflection (in V), and the OMC reflection with the OMC unlocked were measured. The voltages were measured with a digital multimeter (non-portable unit). With the fiber input beam aligned to the fiber, the fiber input and output powers were measured with a power meter.

With the input beam aligned
- Fiber input: 52.5 +/- 0.2 [mW]
- Fiber output: 35.5 +/- 0.2 [mW] (~68% coupling)
- Reflection PD offset: -0.00677 +/- 0.00001 [V]

- Refl PD reading with the OMC unlocked: 6.32 +/- 0.01 [V]
- Refl PD reading with the OMC locked: 0.133 +/- 0.002 [V]
- OMC Trans PD with the OMC locked: -1.72 +/- 0.01 [V] 

With the input beam misaligned
- Refl PD reading with the OMC unlocked: 3.63 +/- 0.01 [V]
- Refl PD reading with the OMC locked: 0.0752 +/- 0.001 [V]
- OMC Trans PD with the OMC locked: -1.00 +/- 0.01 [V] 

The naive mode matching was 0.9779 +/- 0.0003 and 0.9775 +/- 0.0003 without and with misalignment. We initially had roughly 17mW of non-fiber mode incident. And it was increased by roughly 15mW. For the misaligned case, the amount of the OMC-matched carrier was also reduced due to the misalignment. So the actual fiber mode cleaning effect needs more careful quantitative analysis.


The power budget at each part of the setup was modeled as shown in Attachment 1. The blue numbers are the measured values.
The factor a is the ratio of the leakage non-fiber mode into the fiber transmission.
The factor (1-b) is the mode matching of the fiber mode into the OMC mode.

\begin{align} P_{\rm omcrefl} & = a P_{\rm nofib} + b P_{\rm fib} \nonumber \\ P_{\rm fibout} & = P_{\rm omcrefl} + (1-b) P_{\rm fib} \nonumber \\ P_{\rm tot} & = P_{\rm nofib} + P_{\rm fib} \nonumber \end{align}

and

\begin{align} P'_{\rm omcrefl} &= a P'_{\rm nofib} + b P'_{\rm fib} \nonumber \\ P'_{\rm fibout} &= P'_{\rm omcrefl} + (1-b) P'_{\rm fib} \nonumber \\ P_{\rm tot} &= P'_{\rm nofib} + P'_{\rm fib} \nonumber \end{align}

With the calibration between the refl PD and the power meter measurement,
  \begin{align} P_{\rm tot} &= 52.5 \pm 0.2 {[mW]} \nonumber \\ P_{\rm fibout} &= 35.5 \pm 0.2 {\rm [mW]} \nonumber \end{align}
\begin{align} P_{\rm omcrefl} &= 0.78 \pm 0.01\,\,{\rm [mW]} \nonumber \\ P'_{\rm omcrefl} &= 0.460 \pm 0.006\,\,{\rm [mW]} \nonumber \\ P'_{\rm fibout} &= 20.4 \pm 0.13 \,\,{\rm [mW]} \nonumber \end{align}

The solution of the equations is
\begin{align} a &= (4 \pm 4) \times 10^{-4} \nonumber \\ b &= 0.0219 \pm 0.0005 \nonumber \end{align}

So, the leakage of the non-fiber mode to the fiber output is insignificant. Moreover, the number is practically negligible because the mismatching between the fiber and OMC modes is of the order of percent and dominated by the aberration of the collimator (i.e. the OMC reflection looks like concentric higher-order LG modes) with the order of 1~2%.
 

  103   Mon Apr 8 20:56:52 2013 KojiOpticsConfigurationPZT & Curverd Mirror arrangement

Assembly #1:

Mounting Prism #16
PZT #26
Mirror C6

Assembly #2:

Mounting Prism #20
PZT #23
Mirror C5

  149   Fri Aug 9 10:09:56 2013 KojiGeneralGeneralPZT Assembly #3/#4

Yesterday, Jeff and I bonded the PZT assemblies (#3/#4).
The attached is the arrangement of the components

  150   Mon Aug 12 20:22:19 2013 KojiGeneralGeneralPZT Assembly #5/#6

PZT Assembly #5/#6 were glued on Fri Aug 9th

They are removed from the fixture on Mon Aug 12th.

All of the four PZT assemblies were moved to the OMC lab.

  148   Sat Jul 6 17:10:07 2013 KojiMechanicsCharacterizationPZT Response analysis

Analysis of the PZT scan / TF data taken on May 31st and Jun 1st.

[DC scan]

Each PZT was shaken with 10Vpp 1Hz triangular voltage to the thorlabs amp.
The amp gain was x15. Abut 4 TEM00 peaks were seen on a sweep between 0 and 10V.

The input voltage where the peaks were seen was marked. Each peak was mapped on the
corresponding fringe among four. Then the each slope (up and down) was fitted by a iiner slope.
Of course, the PZTs show hystersis. Therefore the result is only an approximation.

PZT1: PZT #26, Mirror C6 (CM1)
PZT2: PZT #23, Mirror C5 (CM2)

PZT arrangement [ELOG Entry]

PZT1:
Ramp Up        13.21nm/V
Ramp Down   13.25nm/V
Ramp Up        13.23nm/V
Ramp Down   13.29nm/V

=> 13.24+/-0.02 nm/V

PZT2:
Ramp Up        13.27nm/V
Ramp Down   12.94nm/V
Ramp Up        12.67nm/V
Ramp Down   12.82nm/V

=> 12.9+/-0.1 nm/V

[AC scan]

The OMC cavity was locked with the fast laser actuation. Each PZT was shaken with a FFT analyzer for transfer function measurments.
(No bias voltage was given)

The displacement data was readout from the laser fast feedback. Since the UGF of the control was above 30kHz, the data was
valid at least up to 30kHz. The over all calibration of the each curve was adjusted so that it agrees with the DC response of the PZTs (as shown above).

The response is pretty similar for these two PZTs. The first series resonance is seen at 10kHz. It is fairly high Q (~30).

  374   Thu Sep 5 15:40:42 2019 shrutiOpticsConfigurationPZT Sub-Assembly

Aim: To find the combinations of mounting prism+PZT+curved mirror to build two PZT sub-assemblies that best minimises the total vertical beam deviation.

(In short, attachment 1 shows the two chosen sets of components and the configuration according which they must be bonded to minimize the total vertical angular deviation.)

The specfic components and configuration were chosen as follows, closely following Section 2.3.3 of T1500060:

Available components:

Mounting prisms: 1,2,12,14,15 (Even though there is mention of M17 in the attachments, it can not be used because it was chipped earlier.)

PZTs: 12,13

Curved mirrors: 10,13

 

Method:

For a given choice of prism, PZT and mirror, the PZT can be placed either at 0deg or 180deg, and the mirror can rotated. This allows us to choose an optimal mirror rotation and PZT orientation which minimises the vertical deviation.

Total vertical angle = $\theta_{v, prism} +\theta_{v,wedge} +\theta_{v,mirror}$

\theta_{v, prism} was measured by Koji as described in elog 369.

\theta_{v, wedge} [\text{arcsec}] = \theta_{PZT} \sin{\frac{\pi \phi_{PZT}}{180}},             \theta_{PZT}, \phi_{PZT} are the wedge angle and orientation respectively and were measured earlier and shown in elog 373 . 

\theta_{v, mirror} [\text{arcsec}] = \frac{180 \times 3600 \times d}{\pi R_{RoC}} \times \sin{\frac{\pi (\phi-\phi_{ROT})}{180}},               The measurement of the location of the curvature bottom (d, \phi) of the mirrors is shown in elog 372 . The optimal \phi_{ROT} is to be found.

 

These steps were followed:

  1. For every combination of prism, PZT, and mirror, the total vertical deviation was minimized with respect to the angle of rotation of the curved mirror computationally (SciPy.optimize.minimize). The results of this computation can be found in Attachment 2: where Tables 1.1 and 2.1 show the minimum achievable deviations for mirrors C10 and C13 respectively, and Tables 1.2 and 2.2 show the corresponding angle of rotation of the mirrors \phi_{ROT} .
  2. From the combinations that show low total deviations (highlighted in red in Attachment 2), the tolerances for 5 arcsec and 10 arcsec deviations with mirror rotation were calculated, and is shown in Tables 1.3, 1.4, 2.3, 2.4 of Attachment 2.
  3. While calculating the tolerances, the dependence of the vertical deviations with rotation were also plotted (refer Attachment 3).
  4. Two sets from available components with low total deviation and high tolerance were chosen. 

 

Result:

These are the ones that were chosen:

  1. M14 + PZT13 at 0deg + C13 rotated by 169deg anticlockwise (tot vertical dev ~ -3 arcsec)
  2. M12 + PZT12 at 0deg + C10 rotated by 88deg clockwise (tot vertical dev ~0 arcsec)

The method of attaching them is depicted in Attachment 1.

 

  102   Mon Apr 8 11:49:18 2013 KojiMechanicsCharacterizationPZT actuator tested at LLO

Test result of the PZTs by Valera and Ryan

PZT  Length Angle
 #   [nm/V] [urad/um]
 11  14.5   17.6
 12  13.8   17.8
 13  11.2   25.0
 14  14.5    6.6
 15  12.5   10.6

 21  14.5    9.7
 22  13.8   28.8
 23  14.5    6.8  ==> Assembly #2
 24  18.5   51.7  ==> Used for prototyping
 25  17.1   13.8
 26  14.5    6.6  ==> Assembly #1
  104   Mon Apr 8 21:11:14 2013 KojiOpticsGeneralPZT assembly gluing

[Jeff, Zach, Koji]

PZT assembly gluing

Glue gun -> to be returned to MIT
Fixtures x2
Al bases, spacers
spare screws
mirrors / prisms / PZTs
IPA bottle
clean tools x2
first contact kit
gloves (7.5)

  106   Tue Apr 9 13:56:09 2013 KojiOpticsGeneralPZT assembly post gluing / pre baking pictures

 

 

  77   Sat Mar 23 13:34:14 2013 KojiOpticsGeneralPZT assembly prototype glued

Prototype PZT assembly

Motivation:

Before we glue the PZT assembly, we need to build a prototype. This is to confirm the heat cure process
does not cause any cracking of the PZT or glass components. The CTE of the PZT is 2~3ppm
(depends on the direction) while the one for Fused Silica is 0.55ppm.

Materials:

- A fused silica substrate, 1/2" in dia. Supplied from Garilynn. I defined the chamfered side as the front side.

- PZT: Noliac NAC2124, serial #24, this is a spare PZT as this has the worst length to angle coupling.

- Mounting Prism: D1102069 SN22. This has the worst perpendicularity among the prisms.

- Fixtures:

D1300185 aLIGO OMC CURVED MIRROR BONDING FIXTURE ASSY
D1300186 aLIGO OMC CURVED MIRROR BONDING FIXTURE FRONT
D1300187 aLIGO OMC CURVED MIRROR BONDING FIXTURE BACK
D1300188 aLIGO OMC CURVED MIRROR BONDING FIXTURE RING

P3223322.jpg

Procedure:

- Wipe all of the components with the isopropanol.

- Attach the back piece of the fixture on the Al wrapped bracket.
(The current 4-40 screws for the middle piece are too long and stick out from the back side of the back piece.
Therefore a 1/16" shim for a 1/2" rod is inserted between the bracket and the back piece)

- Brought a glue package to the lab (10:40PM)

- Loosely attach the middle piece to the back piece with four 4-40 screws.

- Insert the mounting prism in the fixture. Insert the PZT in the fixture too.

- Insert a dummy substrate in the fixture.

- Attach the front piece with spring loaded screws.

- Align the PZT and the optic in the fixture. (Basically apply downward force to them)

- Test the rigidity of the assembly (11:30PM)

- Remove the PZT and the mirror. Apply UV epoxy.
(A single dub was applied for each PZT surface of the PZT but this was too much.)

- Make sure the PZT and the optic are aligned by applying the downward force.

- Illuminate UV light from the front.

- Illuminate UV light from the back. (11:50PM)

Procedural issues:

- Long 4-40 screws (described above)
(Circumvented)

- As the PZT is not constrained with the middle piece, it tends to move vertically and rotationally
because of the wire tension. (This is not a mistake but the design so that the PZT is constrained by the optic.)
Therefore after applying glue on the PZT, the motion of the PZT spreads the glue on the back surface of
the curved mirror.

(Solution to be tried) Our solution is to glue the PZT and the mounting prism first with a dummy optics (made of SF2).
The wires should be tacked somewhere on the mount 

- The amount of glue on the PZT was too much. I gave one dub of glue for each side.
As a result, excess glue leaks out along the ring.

- The front plate has a chamfered hole but this tends to slip and move the mirror vertically.
Later I used the flat side of the plate to hole the mirror.
(Circumvented) It seems that this hold the mirror in a better way as the plate can't rock

- Spring load for the front plate was too strong. This was because the natural length of the spring was too long.
(Circumvented) The spring was cut at the length of the 4-40 screw. Then attaching the screws became completely fine.

P3223323.jpg


Result:

P3233336.jpg P3233348.jpg

Slide show:

  202   Tue Jul 8 18:54:54 2014 KojiMechanicsCharacterizationPZT characterization

Each PZT was swept with 0-150V 11Hz triangular wave.
Time series data for 0.2sec was recorded for each PZT.

The swept voltage at the resonances were extracted and the fringe number was counted.
Some hysteresis is seen as usual.

The upward/downward slopes are fitted by a linear line.

The average displacement is 11.3nm/V for PZT1 and 12.7nm/V.

The PZT response was measured with a FFT analyzer. The DC calibration was adjusted by the above numbers.

  314   Fri Feb 1 12:52:12 2019 KojiMechanicsGeneralPZT deformation simulation

A simple COMSOL simulation was run to see how the PZT deforms as the voltage applied.

Use the geometry of the ring PZT which is used in the OMCs -  NAC2124 (OD 15mm, ID 9mm, H 2mm)
The material is PZT-5H (https://bostonpiezooptics.com/ceramic-materials-pzt) which is predefined in COMSOL and somewhat similar to the one used in NAC2124 (NCE51F - http://www.noliac.com/products/materials/nce51f/)
The bottom surface of the ring was electrically grounded (0V), and mechanically fixed.
Applied 100V between the top and bottom.

 

  156   Thu Aug 22 15:40:15 2013 KojiElectronicsConfigurationPZT endurance test

[Koji, Jeff]

Background

In response to the failure of one of the PZTs on L1OMC (LLO:8366), we have been taking place an endurance test of
the four PZT sub-assemblies in prior to their being glued on the glass breadboard.

According to the technical note by Noliac, the common mode of PZT failure is degradation of the impedance
due to cyclic actuation (like 10^7 times) with over voltage. Therefore our procedure of the test to actuate the PZTs
at least 10^7 times with half voltage of the nominal operating voltage (i.e. nominal 200V) and check the degradation
of the impedance.

Driving signal

For the driving of the PZT, a thorlabs HV amp is used. A source signal of 3.5Vpp with an offset of 1.7V is produced
by DS345 function generator. This signal turns to a sinusoidal signal between 0 and 100V in conjunction with the gain
of 15 at the HV amp.

The maximum driving frequency is determined by the current supply limit of the HV amp (60mA). The capacitance
of each PZT is 0.47uF. If we decide to cycle the signal for 4 PZTs in parallel, the maximum frequency achievable
without inducing voltage drop is 100Hz. This yields the test period of 28hours in order to achive 10^7 cycles.

P8214340.jpg

Initial impedance diagnosis

To check the initial state of the PZTs, a DC voltage of 100V was applied via 1kOhm output resistance.
(Note that this output resistance is used only for the impedance test.)
For each PZTs, both side of the resister showed 99.1V for all measurement by a digital multimeter.
Assuming the minimum resolution (0.1V) of the multimeter, the resistance of each PZT was more than 1MOhm before
the cycling test.

Failure detection

In order to detect any impedance drop of the PZTs, the driving signal is monitored on the oscilloscope via a 1:10 probe.
If there is any significant impedance drop, the driver can't provide the driving current correctly. This can be found
by the deviation of the driving voltage from the reference trace on the oscilloscope (below).

P8214337.jpg

Temperature rise

Because of the loss angle of the PZT capacitance, heating of the PZTs is expected. In order to check the temperature rise,
an IR Viewer (FLIR) was used. We did not take care of careful calibration for the PZT emissibity as what we want was a
rough estimation of the temperature.

Before the driving (LEFT) and at the equilibrium (RIGHT)
IR_0457.jpg
IR_0461.jpg

The temperature change of the PZT was tracked for an hour (below). Fitting of the points indicated that the temperature rise is 2.3degC and the
time constant of 446 sec. This level of temperature rise is totally OK. (Note that the fitting function was T = 27.55 - 2.31 Exp[-t/446.])

 

Results

DAY1:

Start driving
20:27 25.2 degC, status OK
20:33 26.7 degC, status OK
20:41 26.9 degC, status OK
20:48 27.6 degC, status OK
20:54 27.4 degC, status OK
21:10 27.4 degC, status OK
21:37 status OK
Stop driving

70 minutes of driving (i.e. 4.2x10^5 cycles) => no sign of degradation

DAY2:

Start driving
14:15, 24.5 degC, status OK
14:17, 26.0 degC, status OK
14:24, 27.0 degC, status OK
14:40, 26.8 degC, status OK
14:50, 26.8 degC, status OK
15:30, 26.8 degC, status OK
15:55 status OK
17:40 status OK
21:00 status OK (2.43Mcycles + 0.42Mcycles = 2.85Mcycles)
1d+12:00 status OK (7.83Mcycles + 0.42Mcycles = 8.25Mcycles)
1d+15:00 status OK (8.91Mcycles + 0.42Mcycles = 9.33Mcycles)
1d+18:40 status OK (10.23Mcycles + 0.42Mcycles = 10.65Mcycles)
Stop Driving

After 10.65Mcycles no sign of degradationwas found.

  157   Fri Aug 23 19:24:32 2013 KojiElectronicsConfigurationPZT endurance test (II)

The PZT tests were finished with the conclusion that the PZT won't be damaged with our expected usage.


This is another test of the PZTs to make sure small (~10V) reverse voltage does not break the PZTs.

Background

At the site, we decided to use one of the PZT, which is still alive, for the HV and LV actuation.
The HV actuation is limited to 0 to 100V while the LV actuation is 10Vdc with 1Vpp fast dithering.
This means that a reverse voltage upto 10.5V will be applied to the PZT at the worst case.

From the technical note this level of reverse voltage does not induce polarization of the PZT.
The test is to ensure the PZT is not damaged or degraded by this small reverse voltage.

Method

HV drive: Thorlabs HV amp (G=15) driven with DS345 function generator (3.5Vpp+1.7Vdc, 0.1Hz)
=> 0-100V @0.1Hz
=> The hot side of the potential is connected to the positive side of the PZT

LV drive: Phillips function generator (1Vpp+9.5Vdc@1kHz)
The driving frequency is limited by the current output of the function generator.
=> The hot side of the potential is connected to the negative side of the PZT

These drives shares the common ground.

Tests

Testing with spare PZTs 

Started @19:23 (Aug 23)
Stopped @20:15+2d (Aug 25, duration 48h52m)
17600cycles for the 0.1Hz drive.
176Mcycles for the 1kHz drive.

Checked the impedances of PZT1 and PZT2.

Apply 100Vdc via a 1kOhm resister, 0V detected across the 1kOhm resister
This is equivalent to the resistance of 1MOhm.

 

Testing with the PZT subassemblies

Started shaking of the four PZT assemblies @20:20 (Aug 25)
No impedance change observed @11:10+1d
No impedance change observed @15:30+1d
Stopped shaking of the four PZT assemblies @XXXX (Aug 26)

 

Wiring for the test

PZT_shaking.png

 

 

  328   Thu Apr 11 12:15:31 2019 KojiMechanicsConfigurationPZT sub assy mirror orientations
  312   Thu Jan 10 20:45:00 2019 KojiOpticsCharacterizationPZT test cable

As OMC SN002 already has the PZTs connected to the Mighty-Mouse connector, a test cable with a female mighty-mouse connector was made.

A small imperfection: When the cable was inserted to the connector shell, I forgot to mirror the pin out. Therefore the color and pin number do not match.

  203   Thu Jul 10 01:39:38 2014 KojiElectronicsGeneralPZT wire

Rich came to the OMC lab. Pins for the mighty mouse connector were crimped on the 4 PZT wires.
We found the male 4pin mighty mouse connector in the C&B area.

The cable inventory was checked with ICS/DCC combo. It turned out that most of the on-board cables
are at LHO. We decided to send the OMC there and then the cables are installed at the site.

  5   Thu Jun 21 03:07:27 2012 ZachOpticsConfigurationParameter selection / mode definition

EDIT 2 (ZK): As with the previous post, all plots and calculations here are done with my MATLAB cavity modeling utility, ArbCav.

EDIT (ZK): Added input q parameters for OMMT 

found the nice result that the variation in the optimal length vs. variation in the mirror RoC is roughly linear within the ±1% RoC tolerance. So, we can choose two baseline mode definitions (one for each mirror topology) and then adjust as necessary following our RoC measurements.

Bowtie

For R = 2.5 m, the optimal length (see previous post) is LRT = 1.150 m, and the variation in this is dLRT/dR ~ +0.44 m/m.

Here is an illustration of the geometry:

geom_bowtie.png

The input q parameters, defined at the point over the edge of the OMC slab where the beam first crosses---(40mm, 150mm) on the OptoCad drawing---are, in meters:

  • qix = - 0.2276 + 0.6955 i
  • qiy = - 0.2276 + 0.6980 i

 

Non-bowtie

For R = 2.5 m, the optimal length is LRT = 1.246 m, and the variation in this is also dLRT/dR ~ +0.44 m/m.

Geometry:

geom_non-bowtie.png

q parameters, defined as above:

  • qix = - 0.0830 + 0.8245 i
  • qiy = - 0.0830 + 0.8268 i
  17   Mon Aug 13 17:01:35 2012 KojiCleanGeneralParticle Counts

Aug 13, 2012 / 0.5um 1000~2000/(0.1 cu ft) / 0.7um   400-600/(0.1 cu ft) by ATF particle counter (MET ONE 227A)

They are counts/(0.1 ft^3)! These numbers should be multiplied by 10 to know the particle "CLASS".

  20   Tue Sep 25 14:18:14 2012 KojiCleanGeneralParticle Counts

Particle counts

Before the prefilter is installed: 0.5um 1191cnts, 0.7um 346cnts

2:20 prefilter installed
2:25 0.5um 650 / 0.7um 255
3:00 0.5um 578 / 0.7um 99
4:00 0.5um 480 / 0.7um 102
5:00 0.5um 426 / 0.7um 76

They are counts/(0.1 ft^3)! These numbers should be multiplied by 10 to know the particle "CLASS".

  21   Mon Oct 1 16:06:55 2012 KojiCleanGeneralParticle Counts

1. It turned out that the particle counter MET ONE 227A at ATF shows
(particle count)/(0.1 ft^3)


This means that the numbers I saw previously should be multiplied by 10.
So the nominal class of the room was 5000.

2. As our GT-321s have no diffuser, I borrowed a diffuser from 227A.
The diffuser actually increases the count. We need to buy them.
All the measurments below are performed with the diffuser and calibrated in Count/ft^3.

3. Measured the particle level without the HEPA running.

With diffuser: [cnt/ft^3]

  GT-321 #1 GT-321 #2   227A
0.3um 152622 137511 -
0.5um  14706 14823   11860

Over Class 10000

4. The two HEPA fans are turned on at the speed "MED".

Basically no particles are detected in the HEPA booth.

With diffuser, inside of the HEPA booth:

  GT-321 #1 GT-321 #2  227A 
0.3um 0 0
-
0.5um 0 0 0

The particle level in the room (outside of the HEPA booth) is also improved

With diffuser, outside of the HEPA booth GT-321 #1:
0.3 um 18612
0.5 um   1728

5. The two HEPA fans are turned on at the speed "LOW".

Particle levels are still zero inside.

With diffuser, inside of the HEPA booth, GT-321 #1:
0.3 um 0
0.5 um 0

The particle level in the room (outside of the HEPA booth) is also improved
but the cleaning power for 0.3um seems degraded.

With diffuser, outside of the HEPA booth, GT-321 #1:
0.3 um 34488
0.5 um   1386

 

  398   Fri Oct 23 19:09:54 2020 KojiGeneralGeneralParticle counter transfered to Radhika

See this entry: https://nodus.ligo.caltech.edu:8081/40m/15642

  63   Thu Feb 21 18:44:18 2013 KojiOpticsConfigurationPerpendicularity test

Perpendicularity test of the mounting prisms:

The perpendicularity of the prism pieces were measured with an autocollimator.

Two orthogonally jointed surfaces forms a part of a corner cube.
The deviation of the reflected image from retroreflection is the quantity measured by the device.

When the image is retroreflected, only one horizontal line is observed in the view.
If there is any deviation from the retroreflection, this horizontal line splits into two
as the upper and lower halves have the angled wavefront by 4x\theta. (see attached figure)

The actual reading of the autocollimator is half of the wavefront angle (as it assumes the optical lever).
Therefore the reading of the AC times 30 gives us the deviation from 90deg in the unit of arcsec.

SN / measured / spec

SN10: 12.0 arcsec (29 arcsec)

SN11: 6.6 arcsec (16 arcsec)

SN16: 5.7 arcsec (5 arcsec)

SN20: -17.7 arcsec (5 arcsec)

SN21: - 71.3 arcsec (15 arcsec)

 

  246   Tue Dec 15 13:39:13 2015 KojiElectronicsCharacterizationPhase noise measurement of aLIGO EOM drivers

This measurement has been done on Dec 1st, 2015.


The phase noise added by the EOM driver was tested.

The test setup is depicted in the attached PDF. The phase of the RF detector was set so that the output is close to zero crossing as much as possible with the precision of 0.5ns using a switchable delay line box. The phase to voltage conversion was checked by changing the delayline by 1ns. This gave me somewhat larger conversion factor compared to the sine wave test using an independent signal generator. This was due to the saturation of the phase detector as the LO and RF both have similar high RF level for the frequency mixer used.

The measurement has done with 1) no EOM driver involved, 2) one EOM driver inserted in the RF path, and 3) EOM drivers inserted in both the LO and RF paths.

I could not understand why the measurement limit is so high. Also the case 2 seems too low comsidering the noise level for 1) and 3).

At least we could see clear increase of the noise between the case 1) and 3). Therefore, we can infer the phase noise added by the EOM driver from the measurements.

Note: The additional phase noise could be associated with the original amplitude noise of the oscillator and the amplitude-to-phase conversion by the variable attenuator. This means that the noise could be corellated between two EOM drivers. The true test could be done using a PLL with a quiet VCO. Unfortuantely I don't have a good oscillator sufficient for this measurement.

  13   Tue Jul 31 21:33:17 2012 KojiGeneralGeneralPlan Update: August [!]

Completed work of the previous months: [Jul] [Aug] [Sep] [Oct] [Nov] [Dec]


Facility/Supplies

  • Work done
  • Things ordered
    • Office Depot
      • [delivered] Office Depot(R) Brand Stretch Wrap Film, 20 x 1000 Roll, Clear / 445013
      • [delivered] Eveready(R) Gold AA Alkaline Batteries, Pack Of 24 / 158448
      • [delivered] Rubbermaid(R) Roller Sponge Mop / 921841
      • [delivered] Rubbermaid(R) Roller Sponge Mop Replacement / 921858
      • [delivered] Rubbermaid(R) Sanitizing Caddy, 10 Quarts, Yellow / 674125
      • [delivered] Glad(R) Tall Kitchen Trash Bags, 13 Gallon, White, Box Of 28 / 269268
    • Global Industrial Equipment
      • [delivered] Extended Surface Pleated Cartridge Filter Serva-Cell Mp4 Slmp295 12X24X2 Gl    WBB431699
    • Global Industrial Equipment
      • [delivered] Nexel Poly-Z-Brite Wire Shelving 30"W x 21"D x 63"H Nexel Poly-Z-Brite™ Wire Shelving Starter Unit WB189209
      • [delivered] Stem Casters Set of (4) 5" Polyurethane Wheel, 2 With Brakes 1200 lb. Capacity WB500592    
    • Rack Solutions
      • [delivered] Open Frame Server Racks
        1 x 20" Depth Kit (Ideal for Audio/Video or Networking Racks) P/N: 111-1779
        1 x 36U, Rack-111 Post Kit P/N: 111-1728
        1 x Caster Kit for Open Frame RACK-111 P/N: 111-1731
      • [delivered] 36U Side Panel Kit $199.99 P/N: 102-1775
    • Rack shelf
      • [delivered] 1 RMS 19 X 15 SINGLE SIDED NON-VENTED SHELF 70121637
    • Work bench, Stools
      • [not yet] 72"L X 30"W Production Bench - Phenolic Resin Square Edge-Blue Form attached WB237381LBL    
      • [not yet] 72"W Lower Shelf For Bench - 15"D- Blue Form attached WB606951    
      • [not yet] ESD-Safe Vinyl Clean Room Stool with Nylon Base with Drag Chain Blue Form attached WBB560852    
    • P Touch
      • [delivered] Brother PT-2030 Desktop Office Labeler Punch-out product 672828    
      • [delivered] Brother(R) TZe-241 Black-On-White Tape, 0.75 x 26.2 Punch-out product 239384    
      • [delivered] Brother(R) TZe-231 Black-On-White Tape, 0.5 x 26.2 Punch-out product 239400    
    • UV light guide
      • [delivered] Fiber Optic Single Light Guide 5mm OD X 3mm ID X 1M L Note: This light guide can be used with MKIII UV Cure unit. OLB1081
    • Gloves (7.5, 8.0)
      • [delivered] GLOVE ACCTCH NR-LTX SZ7.5 PK25 Punch-out product 79999-306
      • [delivered] GLOVE ACCTCH NR-LTX SZ8 PK25 Punch-out product 79999-308
    • Lab coat (L,XL), Sticky Mat, Shoe Covers (L, XL), Cap, Mask
      • [delivered] LAB XP WH EL WR.COLL. NP L30EA Punch-out product 82007-618
      • [delivered] LAB XPWH EL WR.COLL. NP XL30EA Punch-out product 82007-620    
      • [delivered] VWR MAT ADHESIVE 30L 18X36 BLU Punch-out product 21924-110 (This was too small)
      • [delivered] VWR SHOECVR NSKID AP 2XL 150PR Punch-out product 414004-651    
      • [delivered] VWR SHOECVR NSKID AP XL 150PR Punch-out product 414004-650    
      • [delivered] CAP BOUFFANT 24IN RAYON CS500 Punch-out product 10843-053    
      • [delivered] MASK VLTC TIES N/STRL PK50 Punch-out product 10869-020
    • VWR
      • [delivered] FACE SHIELD UVC-803 Supplier: UVP 33007-151
         
    • [Delivered] Laser safety glasses
  • Work in progress

    •  
  • Work to be done
    • Replacing a file cabinet next to the south wall by a lockable cabinet
    • Laser sign
    • Safety glass holder/rack/shelf
    • Prepare clean supplies ~ glove 8.5,9,9.5
    • Ion gun safety issues: https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=88631
        
  • Design
    • Optical layout - Laser SOP
    • Additional HEPA stage
       
  • Test
    • Confirm particle level
       
  • Note: Optical Table W96" x D48" x H27"

Beaurocracy

  • Laser SOP
  • HV use?
  • UV?

Mechanics

  • Ongoing Work 
    • Cone-shaped wire clamp design (at the OMC end) - Jeff
       
  • Design
    • Wire preparation fixture - Jeff
    • How do we hold the PDs, QPDs, and black glass - we put 2 PDs and 2 QPDs on the PD mounting blacket. - Jeff
    • Integrated solidwork model - Derek
      • Q: How the wires are clamped at the top side?
      • Q: How much the length of the wire should be?
      • Q: Locations of the wire mounts on the plate
    • Cabling investigation:
      • Where do the cables from the feed-thrus anchored?
      • List of the current internal cables and their lengths
      • List of the required internal cables and their lengths
      • Can we route the intermediate stage of the suspension? Do we need new cables?
    • Dummy intermediate stage structure
       
    • Metal templates
      • First, decide an optical design
      • takes at least a month
         
    • Weights how heavy / how many
       
    • Earthquake stop design (Sam B)
       
  • Test
    • Cone-shaped wire clamp test - Jeff/Koji 
    • Balancing the plates
      • The Faraday isolator cage isn't clean
    • Dummy metal payload test at the sites???
       
  • Procedures to be decided
    • PZT alignment
    • Prototyping with metal parts?
    • UV glue? (heat) / gluing test
    • Balance

Optics

  • Things ordered
    • Newport LB servo
    • Halogen Lamp
    • N2 cylinder/lines/filter
  • Ongoing Work 
    • Mirrors to be delivered ~Aug
       
    • Design down select - Between "Single output & BS" vs "Two outputs & no BS"
    • Down selecting procedure:
      1. Assume ELIGO beam component
      2. Assume amount of 9MHz / 45MHz sidebands at the OMC input
      3. Calculate transmitted power
      4. Require HOM to be smaller than the TEM00 offset 
         
    • UV cured epoxy (Quate obtained)
  • Design
    • Mode design for HAM6 layout
    • Finalization of scattering paths
       
  • Tests
    • Measurement of PD angles
    • R&T of each mirror
    • Curvature of the curved mirrors
    • Cavity ref/trans/finesse
    • PD Q.E. & Reflectivity measurement vs incident angle
       
  • Things to be decided / confirmed
    • How to handle optics / assemblies (Talk to the prev people)
    • First contact? (Margot: applicable to a short Rc of ~2.5m)
    • Gluing templates to be designed (how to handle it?)
       
  • PDs
  • Misc
    • CCD beam analyzer (Zach: It is fixed.)
    • Are two PZTs used?
      • YES, for redundancy, range, upconversion tests.
         
  • Things to buy
  • Need to buy a fiber for mode cleaning?
  • Mode content of the ELIGO dark beam?
  • Jitter noise?
  • How to determine the design?
  • Why Fused Silica? (How much is the temp fluctuation in the chamber?)
  • How to align the cavity mirrors, input mirrors, QPDs, PDs, beam dumps.
  • PZTs @LLO
     

Electronics

  • Thorough scrutinization of cabling / wiring / electronics
    • ELIGO OMC Wiring diagram D070536-A2
      • Occupies 2 DB25s -> They were anchored on the sus cage
      • Preamps for DCPDs will be fixed on the ISI table
        -> DB25 for the DCPDs will be anchored on the table
      • Use longer thin cables for the DCPDs in order to route them through the suspension stages
      • Turn the heater cable to the one for the other PZT
  • Electronics / CDS electronics / software
  • Things to be tested
    • QPD/PD pre-selections (QE/noise)
    • PD preamp design (Rich)
    • Functionality test of QPD/PD/PZT

Shipping, storage etc


Jun/July
    - Lab renovation
Aug

    - Mechanics design
    - Mirror delivery
Sept

    - Basic optics test
    - Glue training
Oct
    - Cavity test
Nov

    - Suspending test
Dec
    - Shipping to LLO

Open questions
    Two optical designs
    Procedure
    Modeling
    Clamp design / stencil design
    gluing-installation procedure

  7   Sat Jul 14 02:16:07 2012 KojiGeneralGeneralPlan Update: July

Facility/Supplies

  • Work in progress
    • Floor cleaning
    • Plug slits on the roof of the HEPA booth - blanking panels have been ordered (Peter)
    • Install laser safety barrier (Peter is working on this)
    • Place a sticky mat
       
  • Work to be done
    • Replacing a file cabinet next to the south wall by a lockable cabinet
    • Replacing a lab desk at the west side of the room. (Vladimir's)
    • Replacing Vladimir's rack with nicer one.
    • Laser sign
    • Safety glass holder
    • Prepare clean supplies (Shoes/Coverall/Hats/Gloves) => go to VWR stock room
      • glove 8.5,9,9.5
         
    • Label maker (P-Touch) & Tape
        
  • Design
    • Optical layout - Laser SOP
    • Additional HEPA stage
       
  • Test
    • Confirm particle level
       
  • Note: Optical Table W96" x D48" x H27"

Beaurocracy

  • Laser SOP
  • HV use?
  • UV?

Mechanics

  • Ongoing Work 
    • Cone-shaped wire clamp design (at the OMC end) - Jeff
       
  • Design
    • Wire preparation fixture - Jeff
    • How do we hold the PDs, QPDs, and black glass - we put 2 PDs and 2 QPDs on the PD mounting blacket. - Jeff
    • Integrated solidwork model - Sam
      • Q: How the wires are clamped at the top side?
      • Q: How much the length of the wire should be?
      • Q: Locations of the wire mounts on the plate
    • Cabling investigation:
      • Where do the cables from the feed-thrus anchored? - Sam
      • List of the current internal cables and their lengths - Sam
      • List of the required internal cables and their lengths
      • Can we route the intermediate stage of the suspension? Do we need new cables?
    • Dummy intermediate stage structure
       
    • Metal templates
      • First, decide an optical design
      • takes at least a month
         
    • Weights how heavy / how many
       
  • Test
    • Cone-shaped wire clamp test - Jeff/Koji 
    • Balancing the plates
      • The Faraday isolator cage isn't clean
    • Dummy metal payload test at the sites???
       
  • Procedures to be decided
    • PZT alignment
    • Prototyping with metal parts?
    • UV glue? (heat) / gluing test
    • Balance

Optics

  • Ongoing Work 
    • Mirrors to be delivered ~Aug
       
    • Design down select - Between "Single output & BS" vs "Two outputs & no BS"
    • Down selecting procedure:
      1. Assume ELIGO beam component
      2. Assume amount of 9MHz / 45MHz sidebands at the OMC input
      3. Calculate transmitted power
      4. Require HOM to be smaller than the TEM00 offset 
         
    • UV cured epoxy (Quate obtained)
  • Design
    • Mode design for HAM6 layout
    • Finalization of scattering paths
       
  • Tests
    • Measurement of PD angles
    • R&T of each mirror
    • Curvature of the curved mirrors
    • Cavity ref/trans/finesse
    • PD Q.E. & Reflectivity measurement vs incident angle
       
  • Things to be decided / confirmed
    • How to handle optics / assemblies (Talk to the prev people)
    • First contact? (Margot: applicable to a short Rc of ~2.5m)
    • Gluing templates to be designed (how to handle it?)
       
  • PDs
  • Misc
    • CCD beam analyzer (Zach: It is fixed.)
    • Are two PZTs used?
      • YES, for redundancy, range, upconversion tests.
         
  • Things to buy
  • Need to buy a fiber for mode cleaning?
  • Mode content of the ELIGO dark beam?
  • Jitter noise?
  • How to determine the design?
  • Why Fused Silica? (How much is the temp fluctuation in the chamber?)
  • How to align the cavity mirrors, input mirrors, QPDs, PDs, beam dumps.
     

Electronics

  • Thorough scrutinization of cabling / wiring / electronics
  • Electronics / CDS electronics / software
  • Things to be tested
    • QPD/PD pre-selections (QE/noise)
    • Functionality test of QPD/PD/PZT

Shipping, storage etc


Jun/July
    - Lab renovtion
    - Mechanics design
    - Glue training
Aug
    - Mirror delivery
    - Basic optics test
Sept
    - Cavity test
    - Suspending test
NOV~DEC
    - Shipping to LLO

Open questions
    Two optical designs
    Procedure
    Modeling
    Clamp design / stencil design
    gluing-installation procedure

 


July:Facility/Supplies

  34   Wed Nov 7 20:44:11 2012 KojiGeneralGeneralPlan Update: November [!]

Completed work of the previous months: [Jul] [Aug] [Sep] [Oct] [Nov] [Dec]


  • Work done
    • Wedge measurement (1st trial) [ELOG]
    • RoC measurement [ELOG]
  • Work in progress
    • R&T measurement
    • Wedge measurement
  • Work to be done
    • QPD/PD pre-selections (QE/noise)
    •  
    •  
    •  
    • Misc. / Beaurocracy?
      • Continuous monitoring of the particle level
      • Replacing a file cabinet next to the south wall by a lockable cabinet
      • Ion gun safety issues: https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=88631
      • Laser SOP / HV use? / UV?
  • Things delivered
  • Things ordered
    • Power strips Tripp Lite PS3612 (Ordered Nov. 8, Delivered Nov. 12)
    • Kapton tapes (1in x 6, 1/2in x 12 Delivered Nov. 15)
    • Sticky Mats (VWR 18888-216 Delivered Nov. 12 and 21992-042)
    • Duck tape (PK3) (Delivered Nov. 12)
    • Wipers 12"x12" 2ply x 119 pairs x case15 (Delivered Nov. 12)
    • Syringes (1mL&2mL) & Needles (20G x dozen)
    • Stainless trays with cover (Steve Delivered Nov. 12)
    • Gold Plated allen keys (Steve Delivered Nov. 12)
    • Forceps (Delivered Nov. 12) / Tweezers / Scissors (Delivered Nov. 12)
  • Things to buy / get
    • OMC testing optics / opto-mechanics
    • Black Glass / Black Glass holder / AR ==> Some at the 40m, some from LLO
    • Ionized air blow
      • N2 or Air cylinder: 4N - UHP or 5N - Research Grade.  (... steal from Downs)
    • Clean tools, tray, storage
    • Supply
      • Additional clean supplies ~ glove 8.5,9,9.5
      • Stainless bats / Pure solvents (Metha / Aceton / Iso) / Syringes / Lint free cloth / Paper lens tissue
      • Lab coats
    • ATF
      • Tefron tape
      • Thorlabs 8-32 screw kit / Thorlabs HW-KIT1
      • Pedestal Shims - Newport
  • Things to be done
    • Cavity ref/trans/finesse
    • PD Q.E. & Reflectivity measurement vs incident angle
    • Functionality test of QPD/PD (PeterK) /PZT
       
  • Procedures to be decided
    • PZT alignment
    • UV glue? (heat) / gluing test
    • Balance
    • N2 cylinder/lines/filter
    • Shipping procedure: New shipping cage design on going (Jeff) => Plastic box similar to COC
  • Design
    • Solidworks raytracing model
    • Mode design for HAM6 layout
       
  • Things to be decided / confirmed
    • How to handle optics / assemblies (Talk to the prev people)
    • First contact? (Margot: applicable to a short Rc of ~2.5m)
    • Gluing templates to be designed (how to handle it?)
  • Jitter noise?
  • How to align the cavity mirrors, input mirrors, QPDs, PDs, beam dumps.

Electronics ==> Rich

  29   Tue Oct 16 15:51:01 2012 KojiGeneralGeneralPlan Update: October [!]

Completed work of the previous months: [Jul] [Aug] [Sep] [Oct] [Nov] [Dec]


Facility/Supplies

  • Work in progress
    • RoC measurement
    • R&T measurement
    • Wedge measurement
  • Work to be done
    • Replacing a file cabinet next to the south wall by a lockable cabinet
    • Additional clean supplies ~ glove 8.5,9,9.5
    • Stainless bats
    • Ion gun safety issues: https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=88631
        
  • Design
    • Laser SOP
       
  • Test
    • Continuous monitoring of the particle level
       
  • Note: Optical Table W96" x D48" x H27"

Beaurocracy

  • Laser SOP / HV use? / UV?
  • Procedures to be decided
    • PZT alignment
    • UV glue? (heat) / gluing test
    • Balance
    • N2 cylinder/lines/filter
  • Design
    • Mode design for HAM6 layout
    • Finalization of scattering paths
       
  • Things to be decided / confirmed
    • How to handle optics / assemblies (Talk to the prev people)
    • First contact? (Margot: applicable to a short Rc of ~2.5m)
    • Gluing templates to be designed (how to handle it?)
       
  • PDs
  • Things to buy
  • Need to buy a fiber for mode cleaning?
  • Mode content of the ELIGO dark beam?
  • Jitter noise?
  • How to determine the design?
  • Why Fused Silica? (How much is the temp fluctuation in the chamber?)
  • How to align the cavity mirrors, input mirrors, QPDs, PDs, beam dumps.
  • PZTs @LLO
     

Electronics

  • Thorough scrutinization of cabling / wiring / electronics
    • ELIGO OMC Wiring diagram D070536-A2
      • Occupies 2 DB25s -> They were anchored on the sus cage
      • Preamps for DCPDs will be fixed on the ISI table
        -> DB25 for the DCPDs will be anchored on the table
      • Use longer thin cables for the DCPDs in order to route them through the suspension stages
      • Turn the heater cable to the one for the other PZT
  • Electronics / CDS electronics / software
  • Things to be tested
    • QPD/PD pre-selections (QE/noise)
    • PD preamp design (Rich)
    • Functionality test of QPD/PD/PZT

Shipping, storage etc

  136   Mon Jun 3 21:19:03 2013 KojiGeneralGeneralPlanning

Monday - Evening
(Koji)
[done] - DCPD alignment
[done] - DCPD test & through-put measurement
[done] - Power dependence test
[done] - Apply Protective First Contact Layer on the optic surfaces
[done] - Wiping the OMC

Tuesday - Morning
(Chub)
[done] - Bring the cable from the oven

Tuesday - Afternoon
(Chub/Jeff)
[done] - Cabling of the OMC

Wednesday - Morning
(Jeff/Koji)
[done] - Cable tying down
[done] - Screw tightening for the PDs
[done] - Wrapping / Packing
[done] - Weighting? (65lb for everything)

(Jeff/George)
[done] - Shipping? (or Wednesday)

Items to be shipped together
v - OMC cables between the cable harness to the suspension
v - 1 PZT cable pin
v - DCPD preamp kit
v - toruqe driver & bits
v - kapton sheet/tube
v - Test PD cables
v - Spare diodes
v - QPD amp circuits (just in case)
v - 1GHz PD / Power supply banana-PD cable / 1GHz PD cables

[done] - Installation scheduling with Peter/Brian/(Mike?)
- Travel plan
[done] Koji goes LLO immediately (possible?) 6/6-6/22
  Jeff goes LLO next week?

(Koji)
[done] - Room cleaning

--------------------------
Optical testing plan

Day 0
- Freight and Koji moving

Day 1 Arrival (Thursday or Friday)
- Inspect the shock detector
- Unpacking
- Check the condition of the breadboard
- Place the transportation fixture on the table
- Removing the First Contact layers
- Locking
- Mode matching

Day 2
- Transmission measurement
- Power dependence test
- PD installation / (diode can opening, optional)
- (PD realign, optional)
- diode test

Day 3
- Power dependence test

---------------------------
OMC installation plan

TBD

---------------------------
OMCS installation plan

TBD

---------------------------
Documents

- OMC Hazard analysis (done)
- OMCS Hazard analysis (done)
- OMC instllation procedure
- OMCS instllation procedure
- Work permits

cf. previous documents: E080024, E1300201

---------------------------

---------------------------
Misc
- LIGO access card
controls@lloisc0-work:~$ 2.23-5mW T
2.23-5mW: command not found
controls@lloisc0-work:~$ 2.17 \pm 0.01 R
2.17: command not found
controls@lloisc0-work:~$ 67-68mV inlock
67-68mV: command not found
controls@lloisc0-work:~$ 973mV unlock
973mV: command not found
controls@lloisc0-work:~$ Pin 5.47+-0.014.4
No command 'Pin' found, did you mean:

 

  395   Thu Oct 8 19:55:22 2020 KojiGeneralCharacterizationPower Measurement of Mephisto 800NE 1166A

The output of Mephisto 800NE (former TNI laser) was measured.
The output power was measured with Thorlabs sensors (S401C and S144C). The reference output record on the chassis says the output was 837mW at 2.1A injection.
They all showed some discrepancy. Thus we say that the max output of this laser is 1.03W at 2.1A injection based on the largest number I saw.

  227   Wed Jul 22 09:43:01 2015 KojiElectronicsAM Stabilized EOM DriverPower supply test of the EOM/AOM Driver

Serial Number of the unit: S1500117
Tester: Koji Arai
Test Date: Jul 22, 2015

1) Verify the proper current draw with the output switch off:

+24 Volt current: 0.08 A Nom.
-24 Volt current: 0.07 A Nom.
+18 Volt current: 0.29 A Nom.
-18 Volt current: 0.24 A Nom.

2) Verify the proper current draw with the output switch on:
+24 Volt current: 0.53 A Nom.
-24 Volt current: 0.07 A Nom.
+18 Volt current: 0.21 A Nom.
-18  Volt current: 0.26 A Nom.

3) Verify the internal supply voltages:

All look good.

TP13 -5.001V
TP12 -15.00
TP11 -21.05
TP10 -10.00
TP5  -18.19
TP6  -24.22
TP2  +24.15
TP3  +18.22
TP9  + 9.99
TP17 +24.15
TP14 +21.04
TP15 +15.00
TP16 + 4.998

4) Verify supply OK logic:
All look good. This required re-disassembling of the PCBs...

Check then pin 5 on U1 (connected to R11) and U4 (connected to R23):

U1 3.68V (=Logic high)
U4 3.68V (=Logic high)

5) Verify the relays for the power supply sequencing: OK

Turn off +/-24 V. Confirm Pin 5 of K1 and K2 are not energized to +/-18V. => OK
Turn on +/-24 V again. Confirm Pin 5 of K1 and K2 are now energized to +/-18V. => OK

6) Verify noise levels of the internal power supply voltages:

TP13 (- 5V) 13nV/rtHz@140Hz
TP12 (-15V) 22
nV/rtHz@140Hz
TP11 (-21V) 32
nV/rtHz@140Hz
TP10 (-10V) 16nV/rtHz@140Hz
TP9  (+10V)  9
nV/rtHz@140Hz
TP14 (+21V) 21nV/rtHz@140Hz
TP15 (+15V) 13nV/rtHz@140Hz
TP16 (+ 5V) 11nV/rtHz@140Hz

 

Note that the input noise of SR785 is 9~10nV/rtHz@140Hz with -50dBbpk input (AC)

 

  399   Fri Nov 6 18:38:00 2020 KojiGeneralGeneralPowermeter lent from OMC Lab to 2um ECDL

Thorlabs' powermeter controler + S401C head was lent from OMC Lab. Returned to OMC Jul 15, 2022 KA

https://nodus.ligo.caltech.edu:8081/SUS_Lab/1856

  290   Thu Nov 30 12:18:41 2017 StephenGeneralGeneralPreparation for Modal Testing on 4 December

Norna Robertson, Stephen Appert ||  29 Nov 2017, 2 pm to 4 pm  ||  227 Downs, CIT

We made some preparations for modal testing, but did not have enough time to make measurements. Below is an after-the-fact log, including some observations and photos of the current state of the OMC bench.

  1. Previous testing results at T1700471 (technical note in progress as of 30 Nov 2017).
    1. One goal of the next round: add damping material to equate with damping material of T1600494.
    2. Second goal of the next round: use a more localized sweep to better resolve the body mode around 1080 Hz -1100 Hz
  2. Transport Fixture was opened without issue, revealing the "Top" (suspending and cable routing) surface of the bench. Damping stacks were still in place from previous testing
  3. We removed the bolts from the damper stacks, but found that all masses with metal-viton interfaces had adhered to viton washers, causing the stacks to stick together.
    1. By using an allen key as a lever to wedge apart bottom mass and the bracket where they were joined by a viton washer, we separated the masses from the bracket.
    2. An allen key was used as a lever to push apart the two masses, which were also joined by a viton washer
    3. Once exposed, viton washers were pried from metal surfaces.
  4. After the damper stacks had been detached from the  No viton washer appeared to leave any residue or particulate - the separated parts all appeared as clean as they had been at the onset.
  288   Fri Sep 8 15:14:05 2017 KojiFacilityGeneralPreparation for the plumbing work

[Steve, Aaron, Koji]

We've finished the preparation for the forthcoming plumbing work on (nominally) Sept 16th Saturday.
We've covered most of the west side of the OMC lab with plastic sheets and wraps.

Some tips:

  • The plastic sheets Eric gave us were a bit too thin and pron to got torn. Thicker sheets are preferable.
  • The blue tape that Eric gave us was very useful.
  • The stretch wrap film, which I bought long time ago, was so useful. Office Depot "Office Depot(R) Brand Stretch Wrap Film, 20 x 1000 Roll, Clear" PN: 445013
  • We also used patches of Kitchen Trash Bags to cover some small opening of the large sheets. Office Depot "Glad(R) Tall Kitchen Trash Bags, 13 Gallon, White, Box Of 28" PN 269268
  264   Mon Aug 15 10:09:10 2016 KojiGeneralGeneralPrev H1 OMC shipped to CIT

Previous H1 OMC shipped from LHO to CIT

https://ics-redux.ligo-la.caltech.edu/JIRA/browse/Shipment-8196

  44   Tue Dec 18 20:04:40 2012 KojiOpticsCharacterizationPrism Thickness Measurement

The thicknesses of the prism mirrors (A1-A5) were measured with micrometer thickness gauge.
Since the thickness of the thinner side (side1) depends on the depth used for the measurement,
it is not accurate. Unit in mm.

A1: Side1: 9.916, Side2: 10.066 => derived wedge angle: 0.43deg
A2: Side1: 9.883, Side2: 10.065 => 0.52
A3: Side1: 9.932, Side2: 10.062 => 0.38
A4: Side1: 9.919, Side2: 10.060 => 0.40
A5: Side1: 9.917, Side2: 10.058 => 0.40

prism.png

  274   Thu Jan 19 20:57:53 2017 KojiSupplyGeneralPurchase

Ordered:

Office Depot
v AA battery Qty. 24
v 9V battery Qty. 4
v Floor cable cover (6ft)

Thorlabs
v HV PZT Driver
v Lenses

  275   Thu Feb 16 17:23:12 2017 KojiSupplyGeneralPurchase

 

  321   Thu Apr 4 20:07:39 2019 KojiSupplyGeneralPurchase

== Office Depot ==
Really Useful Box 9L x 6 (delivered)
Really Useful Box 17L x 5 (ordered 4/4)
P-TOUCH tape (6mm, 9mm, 12mmx2, 18mm) (ordered 4/4)

== Digikey ==
9V AC Adapter (- inside, 1.3A) for P-TOUCH (ordered 4/4)
12V AC Adapter (+ inside, 1A) for Cameras (ordered 4/4)

== VWR ==
Mask KIMBERLY CLARK "KIMTECH Pure M3" ISO CLASS 3 (ordered 4/4)

  258   Tue Apr 5 18:14:55 2016 KojiGeneralLoan / LendingQPD Lending Crackle

Xiaoyue

QPD head
X-Z stage
Mounting brackets
DB15 cable
QPD matrix circuit
+/-18V power supply cable

  132   Thu May 30 15:00:28 2013 KojiOpticsGeneralQPD alignment

The QPD alignment was adjusted using the aligned beam to the cavity and the 4ch transimpedance amplifier.

As I have a test cable for the QPD, I attached a DB9 connector on it so that I can use the QPD transimpedance
amplifier to read the photocurrent. The transimpedance of the circuit is 1kV/A.
As this board (D1001974) does not have X/Y/SUM output, I quickly made the summing circuit on a universal
board I took from Japan a while ago.

The spot on the QPD1 (shorter arm side) seems too low by ~0.64mm. It seems that the QPD is linearly responding
to the input misalignment, so there is no optical or electrical problem.

As I wonder how much I can improve the situation by replacing the diodes, I swapped the diodes between QPD1 and QPD2.
Now QPD1 and QPD2 have the diode #43 and #38, respectively. It improved the situation a llitle (about 60um).
But the beam is still 0.58mm too low. 95% of the power is on the upper two elements.
Of course this is at the edge of the linear range.
I confirmed we still can observe the cavity is fringing even with the beam is aligned on this QPD. So this may be
sufficient for the initial alignment.

The QPD2 was in a better situation. The spot is about 100um too low but this is still well with in the linear range.

The incident powers on the diodes were also measured. The estimated responsivities and Q.E.s are listed below.
The reflection from the diode is adjusted to hit the beam dump properly.

Here are the raw numbers


QPD#            QPD1       QPD2
Diode#          #43        #38

-------------------------------------
Power Incident  118.8 uW   115.7uW
Sum Out          78.8 mV   84.6 mV
Vertical Out     69.1 mV   11.9 mV
Horizontal Out    9.8 mV   -1.6 mV
SEG1             -1.90 mV -17.8 mV
SEG2             -2.18 mV -17.5 mV
SEG3            -32.0 mV  -25.3 mV
SEG4            -42.0 mV  -23.8 mV
-------------------------------------
Responsivity[A/W] 0.66      0.73
Q.E.              0.77      0.85
-------------------------------------

Arrangement of the segments
View from the beam
/ 2 | 1 X
|---+---|
\ 3 | 4 /

  133   Fri May 31 05:46:54 2013 KojiOpticsGeneralQPD alignment

Peter F suggested to check the bottom surface of the PD housings if there is any protrusion/interference/whatever.
And that was true! It was found that the front side of QPD1 (Left) was lifted by a machining burr.
It seems that this burr consistently exists as the other one also have it (see QPD2 picture (right)) although it is not too terrible compared to the one in QPD1.

QPD1.JPG QPD2.JPG

Once these burrs were removed, the spots were found on the right position of each diode.
From the measurement of the power on each segment, the positions of the spots were estimated. (listed in the table)
They indicate that the spots are within 0.1mm from the center. This is good enough.

The quantum efficiency was measured from the incident power and the sum output. It seems that there are
some difference between the diodes. The numbers are consistent with the measurement the other day.

QPD#              QPD1       QPD2
Diode#            #43        #38

-------------------------------------
Power Incident     84.7 uW   86.2 uW
Sum Out            56   mV   61   mV
Vertical Out       -6.8 mV   10   mV
Horizontal Out      4.2 mV    8.8 mV
SEG1              -17   mV  -15   mV
SEG2              -14.5 mV  -11   mV
SEG3              -11   mV  -15   mV
SEG4              -13   mV  -20   mV
-------------------------------------
Spot position X   +25   um  +46   um  (positive = more power on SEG1 and SEG4)
Spot position Y   -42   um  +46   um  (positive = more power on SEG3 and SEG4)
-------------------------------------

Responsivity[A/W] 0.66      0.71
Q.E.              0.77      0.82
-------------------------------------

Arrangement of the segments
View from the beam
/ 2 | 1 X
|---+---|
\ 3 | 4 /

---------------

I(w,x,y) = Exp[-2 (x^2 + y^2)/w^2]/(Pi w^2/2)

(SEG_A+SEG_B-SEG_C-SEG_D)/(SEG_A+SEG_B+SEG_C+SEG_D) = Erf[sqrt(2) d/w]

d: distance of the spot from the center
w: beam width

  171   Tue Oct 15 18:50:08 2013 KojiOpticsCharacterizationQPD alignment

1) Deburr the bottom surfaces of the QPD housings

2) Aligned the QPDs

 

QPD#              QPD1       QPD2
Housing#          #004       #008
Diode#            #44        #46
Shim              1.75mm 001 1.25mm 001

-------------------------------------
Power Incident    125.7 uW  126.4 uW
Sum Out            80.1 mV   78.9 mV
Vertical Out      + 3.4 mV    0   mV
Horizontal Out    -23.7 mV  -26   mV
SEG1              -15.6 mV  -13.2 mV
SEG2              -13.1 mV  -13.3 mV
SEG3              -29.0 mV  -26.4 mV
SEG4              -23.2 mV  -26.3 mV
-------------------------------------
Spot position X   -13   um  - 0.8 um  (positive = more power on SEG1 and SEG4)
Spot position Y   +93   um +107   um  (positive = more power on SEG3 and SEG4)
-------------------------------------

Responsivity[A/W] 0.64      0.62
Q.E.              0.74      0.73
-------------------------------------

Arrangement of the segments
View from the beam
/ 2 | 1 X
|---+---|
\ 3 | 4 /

---------------

I(w,x,y) = Exp[-2 (x^2 + y^2)/w^2]/(Pi w^2/2)

(SEG_A+SEG_B-SEG_C-SEG_D)/(SEG_A+SEG_B+SEG_C+SEG_D) = Erf[sqrt(2) d/w]

d: distance of the spot from the center
w: beam width

  115   Wed Apr 17 07:30:04 2013 KojiOpticsGeneralQPD path glued

Yesterday, all of the glass components for the QPD path were glued.

- Check the alignment of the beam with the cavity.

- Placed the prisms

- Placed the QPD mount for the gluing test. An alignment disk instead of a diode was placed on the mount.

- Checked the spot positions at the QPDs. A CCD camera with a lens was used to find the spot.
  The spots were ~0.5mm lower on the QPD1, and ~1mm lower on the QPD2.

- Glued the first steering mirror while the spot position was continuously monitored.

- Glued the BS in the QPD path while the spot position was monitored.

- FInally a glass bracket was glued.

- The spot on QPD2 was too low to absorb by the QPD shim.

- Once the steering mirror was clamped by a cantilever spring (to prevent slipping), the spot moved up a bit.
  (Or, we should say, the cantilever misaligned the optics a bit in pitch in a preferrable direction.)

- The other steering mirror is clamped by a cantilever spring (to prevent slipping), the spot moved up a bit.
  Or, we should say, the cantilever misaligned the optics a bit in pitch in a preferrable direction.)

- The last steering mirrors was also glued in a same way. As a result the spot is 0.5mm below the center of the alignment disk.

- Once the PD mounting brackets were glued, we can't place the QPD mount on it as the PEEK bar can't be inserted without moving the gluing template.

- The QPD mount with out the glass bracket was used to check the alignment of the beam dumps.
  As the beam dumps have a wide aperture and the yaw alignment of the QPD is big, we could accommodate the beams in the dumps easily.

- The dumps were glued.

  231   Mon Aug 10 02:11:47 2015 KojiElectronicsAM Stabilized EOM DriverRF AM Measurement Unit E1500151

This is an entry for the work on Aug 3rd.

LIGO DCC E1500151

Power supply check

- Removed the RF AM detector board and exposed the D0900848 power board. The board revision is Rev. A.

- The power supply voltage of +30.2V and -30.5V were connected as +/-31V supplies. These were the maximum I could produce with the bench power supply I had. +17.2V and -17.1V were supplied as +/-17V supplies.

- Voltage reference: The reference voltages were not +/-10V but +/-17V. The cause was tracked down to the voltage reference chip LT1021-10. It was found that the chip was mechanically destroyed (Attachment 1, the legs were cut by me) and unluckily producing +17V. The chip was removed from the board. Since I didn't have any spare LT1021-10, a 8pin DIP socket and an AD587 was used instead. Indeed AD587 has similar performance or even better in some aspects. This fixed the reference voltage.

- -5V supply: After the fix of the reference voltage, I still did not have correct the output voltage of -5V at TP12. It was found that the backpanel had some mechanical stress and caused a leg of the current boost transister cut and a peeling of the PCB pattern on the component lalyer (Attachment 2). I could find some spare of the transister at the 40m. The transister was replaced, and the pattern was fixed by a wire. This fixed the DC values of the power supply voltages. In fact, +/-24V pins had +/-23.7V. But this was as expected. (1+2.74k/2k)*10V = 23.7V .

- VREFP Oscillation: Similarly to the EOM/AOM driver power supply board (http://nodus.ligo.caltech.edu:8080/OMC_Lab/225), the buffer stage for the +10V has an oscillation at 762kHz with 400mVpp at VREFP. This was fixed by replacing C20 (100pF) with 1.2nF. The cap of 680pF was tried at first, but this was not enough to completely elliminate the oscilation.

- VREFN Oscillation: Then, similarly to the EOM/AOM driver power supply board (http://nodus.ligo.caltech.edu:8080/OMC_Lab/225), the amplifier and buffer stage for the -10V has an oscillation at 18MHz with 60mVpp at VREFN. This was fixed by soldering 100pF between pin6 and pin7 of U6.

- Voltage "OK" signal: Checked the voltage of pin5 of U1 and U4 (they are connected). Nominally the OK voltage had +2.78V. The OK voltage turned to "Low (~0V)" when:
The +31V were lowered below +27.5V.
The +31V were lowered below -25.2V.
The +17V were lowered below +15.2V.
The +17V were lowered below -15.4V.

- Current draw: The voltage and current supply on the bench top supplies are listed below

+30.2V 0.09A, -30.5V 0.08A, +17.2V 0.21A, -17.1V 0.10A

- Testpoint voltages:

TP12(-5V) -5.00V
TP11(-15) -14.99V
TP10(-24V) -23.69V
TP9(-10V) -9.99V
TP5(-17V) -17.15V
TP6(-31V) -30.69

TP2(+31V) +30.37V
TP3(+17V) +17.24V
TP8(+10V) +10.00V
TP16(+28V) +28.00V
TP13(+24V) +23.70V
TP14(+15V) +15.00V
TP15(+5V) +5.00V

 

  232   Mon Aug 10 11:39:40 2015 KojiElectronicsAM Stabilized EOM DriverRF AM Measurement Unit E1500151

Entry for Aug 6th, 2015

I faced with difficulties to operate the RF AM detectors.

I tried to operate the RF AM detector. In short I could not as I could not remove the saturation of the MON outputs, no matter how jiggle the power select rotary switches. The input power was 10~15dBm.

D0900761 Rev.A
https://dcc.ligo.org/LIGO-D0900761-v1

I've measured the bias voltage at TP1. Is the bias such high? And does it show this inversion of the slope at high dBm settings?

Setting Vbias
 [dBm]   [V]

   0    21.4
   2    21.0
   4    20.5
   6    19.8
   8    18.8
  10    17.7
  12    16.3
  14    14.2
  16    11.9
  18    10.6
  20    11.8
  22    15.0


The SURF report (https://dcc.ligo.org/LIGO-T1000574) shows monotonic dependence of Vbias from 0.6V to 10V (That is supposed to be the half of the voltage at TP1). 
I wonder I need to reprogram FPGA?

But if this is the issue, the second detector should still work as it has the internal loop to adjust the bias by itself.
TP3 (Page 1 of D0900761 Rev.A) was railed. But still MON2 was saturated.
I didn't see TP2 was also railed. It was ~1V (not sure any more about the polarity). But TP2 should also railed.

Needs further investigation

  233   Mon Aug 10 11:57:17 2015 KojiElectronicsAM Stabilized EOM DriverRF AM Measurement Unit E1500151

Spending some days to figure out how to program CPLD (Xilinx CoolRunner II XC2C384).

I learned that the JTAG cable which Daniel sent to me (Altium JTAG USB adapter) was not compatible with Xilinx ISE's iMPACT.

I need to use Altium to program the CPLD. However I'm stuck there. Altium recognizes the JTAG cable but does not see CPLD. (Attachment 1)

Upon the trials, I followed the instruction on awiki as Daniel suggested.
http://here https://awiki.ligo-wa.caltech.edu/aLIGO/TimingFpgaCode

Altium version is 15.1. Xilinx ISE Version is 14.7

  234   Mon Aug 10 12:09:49 2015 KojiElectronicsAM Stabilized EOM DriverRF AM Measurement Unit E1500151

Still suffering from a power supply issue!

I have been tracking the issues I'm having with the RF AM detector board.

I found that the -5V test point did not show -5V but ~+5V! It seemed that this pin was not connected to -5V but was passive.

I removed the RF AM detector board and exposed the power board again. Pin 11 of P3 interboard connector indeed was not connected to TP12 (-5V). What the hell?

As seen in the attached photo, the PCB pattern for the Pin 11 is missing at the label "!?" and not driven. I soldered a piece of wire there and now Pin11 is at -5V.


This fix actually changed several things. Now the bias setting by the rotary switches works.

Setting BIAS1
 [dBm]   [V]

   0    0.585
   2    0.720
   4    0.897
   6    1.12
   8    1.42
  10    1.79
  12    2.25
  14    2.84
  16    3.60
  18    4.56
  20    5.75
  22    7.37

This allows me to elliminate the saturation of MON1 of the first RF AM detector. I can go ahead to the next step for the first channel.

Now the bias feedback of the second detector is also behaving better. Now TP2 is railing.

Still MON2 is saturated. So, the behavior of the peak detectors needs to be reviewed.

  238   Fri Aug 28 02:14:53 2015 KojiElectronicsAM Stabilized EOM DriverRF AM Measurement Unit E1500151 ~ 37MHz OCXO AM measurement

In order to check the noise level of the RFAM detector, the power and cross spectra for the same signal source
were simultaneously measured with the two RFAM detectors.


As a signal source, 37MHz OCXO using a wenzel oscillator was used. The output from the signal source
was equaly splitted by a power splitter and fed to the RFAM detector CHB(Mon1) and CHA(Mon2).

The error signal for CHB (Mon1) were monitored by an oscilloscope to find an appropriate bias value.
The bias for CHA are adjusted automatically by the slow bias servo.

The spectra were measured with two different power settings:

Low Power setting: The signal source with 6+5dB attenuation was used. This yielded 10.3dBm at the each unit input.
The calibration of the low power setting is dBc = 20*log10(Vrms/108). (See previous elog entry)

High Power setting: The signal source was used without any attenuation. This yielded 22.4dBm at the each unit input.
The calibration for the high power setting was measured upon the measurement.
SR785 was set to have 1kHz sinusoidal output with the amplitude of 10mVpk and the offset of 4.1V.
This modulation signal was fed to DS345 at 30.2MHz with 24.00dBm
The network analyzer measured the carrier and sideband power levels
30.2MHz 21.865dBm
USB    -37.047dBm
LSB    -37.080dBm  ==> -58.9285 dBc (= 0.0011313)

The RF signal was fed to the input and the signal amplitude at Mon1 and Mon2 were measured
MON1 => 505   mVrms => 446.392 Vrms/ratio
MON2 => 505.7 mVrms => 447.011 Vrms/ratio
dBc = 20*log10(Vrms/446.5).


Using the cross specrum (or coherence)of the two signals, we can infer the noise level of the detector.

Suppose there are two time-series x(t) and y(t) that contain the same signal s(t) and independent but same size of noise n(t) and m(t)

x(t) = n(t) + s(t)
y(t) = m(t) + s(t)

Since n, m, s are not correlated, PSDs of x and y are

Pxx = Pnn + Pss
Pyy = Pmm+Pss = Pnn+Pss

The coherence between x(t) and y(t) is defined by

Cxy = |Pxy|^2/Pxx/Pyy = |Pxy|^2/Pxx^2

In fact |Pxy| = Pss. Therefore

sqrt(Cxy) = Pss/Pxx

What we want to know is Pnn

Pnn = Pxx - Pss = Pxx[1 - sqrt(Cxy)]
=> Snn = sqrt(Pnn) = Sxx * sqrt[1 - sqrt(Cxy)]

This is slightly different from the case where you don't have the noise in one of the time series (e.g. feedforward cancellation or bruco)


Measurement results

 

Power spectra:
Mon1 and Mon2 for both input power levels exhibited the same PSD between 10Hz to 1kHz. This basically supports that the calibration for the 22dBm input (at least relative to the calibration for 10dBm input) was corrected. Abobe 1kHz and below 10Hz, some reduction of the noise by the increase of the input power was observed. From the coherence analysis, the floor level for the 10dBm input was -178, -175, -155dBc/Hz at 1kHz, 100Hz, and 10Hz, respectively. For the 22dBm input, they are improved down to -188, -182, and -167dBc/Hz at 1kHz, 100Hz, and 10Hz, respectively.

 

  240   Tue Sep 8 10:55:31 2015 KojiElectronicsAM Stabilized EOM DriverRF AM Measurement Unit E1500151 ~ 37MHz OCXO AM measurement

Test sheet: https://dcc.ligo.org/LIGO-E1400445

Test Result (S1500114): https://dcc.ligo.org/S1500114

ELOG V3.1.3-