 Tue Feb 19 17:14:56 2013, Chloe, Update, , QPD Circuit
|
I finished working out the circuit and figured out where the broken connections were. This is diagrammed in my notebook (will draw up more nicely and
include in future elog post). Within the QPD circuitry, it seems like there are already opamps which regulate the circuit. I need to discuss the final
diagram further with Eric. |
 Fri Feb 22 13:03:49 2013, Manasa, Update, , MC REFL PD murder 
|
[Yuta, Manasa]
We turned IFO power back to 1.25W by removing the attenuator and forgot that the Y1 mirror before the REFL PD must be replaced with BS 10% before |
|
Fri Feb 22 17:33:38 2013, Chloe, Update, , QPD circuit diagram
|
Today I tested the circuitry within the QPD to make sure I had put it back together correctly. The output was able to detect when a laser pointer was
shone on different quadrants of the QPD when hooked up to the oscilloscope, so fixing the QPD worked!
Following this, I spent awhile understanding what was going on with the circuit reading from the QPD. I concluded that the opamp on the QPD circuit |
|
Tue Feb 26 17:36:28 2013, Chloe, Update, , QPD Circuit
|
I corrected the circuit diagram I constructed last time - it would read 0 output most of the time because I made a mistake with the op amps. This will
be attached once I discuss it with Eric.
I searched the 40m lab and ended up finding a breadboard in the Bridge lab. I then spent awhile trying to remove the QPD from the circuit board |
|
Wed Feb 27 14:59:01 2013, Evan, Update, , Altered MC demodulation phase
|
I took out a short (~12 cm) SMA cable from the "LO input" path into the MC demod board in an attempt to maximize the power in Q and minimize
the power in I. The path might benefit from being shortened a little more, but it's hard to tell since I is noisy. (In the attached plots, channel 1 is
Q and channel 2 is I.) |
|
Wed Feb 27 17:43:54 2013, Riju, Update, , Photodiode transimpedance
|
| Here is the transimpedance for the other PD used for MC REFL |
|
Wed Feb 27 18:01:46 2013, Koji, Update, , Photodiode transimpedance
|
How much is the exact resonant frequency?
And what's the unit of the plot? The resonant "transimpedance" in the unit
of Ohm can not be ~100. |
|
Wed Feb 27 18:17:05 2013, Riju, Update, , Photodiode transimpedance
|
Quote:
How much is the exact resonant frequency? |
|
Wed Feb 27 18:38:51 2013, Riju, Update, , Photodiode transimpedance
|
Quote:
|
|
Tue Mar 5 17:23:06 2013, Chloe, Update, , QPD Adding/Subtracting Circuit
|
Today I finished building the adding/subtracting circuit for the QPD and tested that the QPD could see a laser moving across its visual field for both
pitch and yaw. It didn't seem to behave weirdly (saturate) at the edges, but I need to test this more carefully to be sure.
However, this circuit uses many op amps, which will cause problems for building the actual circuit to fit into the QPD box. I am trying to figure |
|
Thu Mar 14 16:56:16 2013, Chloe, Update, , QPD Circuit Design
|
I have sketched out the circuit design for the QPD. However, it seems like even when using a different opamp configuration, which I talked to Eric about
on Friday, space will be a problem. It may be possible to squeeze everything onto a single circuit board to fit in the QPD box but what I think is more
likely is that I will need to have 2 separate circuit boards both mounted within the box, one which integrates the signal from the QPD and the other which |
|
Mon Mar 25 16:51:43 2013, Chloe, Update, , Final QPD Circuit Design
|
This is the final version of the QPD circuit I'm going to build. After playing around with the spatial arrangement, this should fit into the box that
I was planning to use, although it will be a rather tight fit. The pitch, yaw, and summing circuit will be handled with a quad op amp. Planning to meet
with Eric tomorrow to figure out the logistics of building things. |
|
Mon Mar 25 23:27:26 2013, Chloe, Update, , QPD Circuit
|
In order to test the mount vibrations, I will likely try and make a different circuit work (with the summing/subtracting on an external breadboard) and
designing an optimal circuit will be a side project. This is the circuit with the power supply Rana came up with, and the design I had in mind for the
rest of the circuit. In my free time, I will try to figure out what parts to get that reduce noise and slowly work on building this, since it would be |
|
Tue Mar 26 17:32:30 2013, Chloe, Update, , QPD/ECDL Progress
|
I built the summing/subtracting circuit on the breadboard, and hooked this up with one of the other QPDs I found (image of setup attached). I wasn't
able to get this to read the correct signals when testing with a laser pointer after a couple of hours of troubleshooting... I will hopefully get this
working in the next day or 2... |
|
Mon Apr 1 16:13:50 2013, Chloe, Update, , QPD
|
Because we would like to get started on testing mount vibrations as soon as possible, I've been trying to get one of the other QPDs we found to work
with the summing/subtracting circuit on a breadboard. I've been using a power supply that I think Jamie built 15 years ago... which seems to be broken
as of today, since I no longer read any signal from it with an oscilloscope. |
|
Wed Apr 3 16:03:59 2013, Chloe, Update, , QPD Voltage Regulators
|
The voltage regulator on the QPD breadboard seems to be having problems... yesterday Eric helped me debug my circuit and discovered that the +12V regulator
was overheating, so we replaced it. Today, I found that the -12V regulator was also doing the same thing, so I replaced it. However, it's still overheating.
We checked all of the setup for the power regulators yesterday, so I'm not sure what's wrong. |
|
Wed Apr 3 18:27:03 2013, Koji, Update, , QPD Voltage Regulators
|
| Breadboards may not be suitable for a reliable work. Why don't you switch to any protoboard and real soldering? |
|
Tue Apr 23 16:31:13 2013, Eric, Configuration, , PD frequency response
|
[Eric, Riju]
Summary: Routing Fibers on AP table for Photo Diode Frequency Response Measurement System
Objective: We are to set-up one simultaneous transfer-function measurement system for all the RF-PDs present in 40m lab. A diode laser output is |
|
Wed Apr 24 14:24:40 2013, Riju, Update, , PD frequency response
|
Here I am attaching the first schematic diagram of the PD frequency response set-up, I will keep updating it with relevant informations with the
progress of the work.
Description: Our objective is to set-up one simultaneous |
|
Thu Apr 25 17:56:28 2013, Riju, Configuration, , PD frequency response
|
[Eric, Riju]
Today we have routed the fibers from 1x16 fiber splitter to POX table for POX11 PD and POP55 PD. Also we labeled the fibers on AP table, they have
been fixed on the table. The photo of the table after work is attached here. We will do it for POX table tomorrow. |
|
Thu Apr 25 18:58:06 2013, Koji, Configuration, , PD frequency response
|
No.... what I told was to put the roll next to the splitter, not
on the table.
The table area is more precious than the rack space. |
|
Fri Apr 26 17:08:42 2013, Riju, Configuration, , PD frequency response
|
Quote:
No.... what I told was to put the roll next to the splitter, |
|
Tue Apr 30 12:25:23 2013, Chloe, Update, , QPD
|
Annalisa and I met yesterday and fixed the voltage regulator on the breadboard so the QPD circuit is working. We will meet with Eric on Thursday to determine
the course of action with measurements. |
|
Tue May 7 03:08:12 2013, Jenne, Update, , PRM yaw responsible for RIN
|
Koji spent some time earlier this evening exploring where the excess RIN that we see in the PRC is coming from.
He did this by locking the PRMI (MICH on AS55Q, PRCL on REFL33I, Pnorm for MICH = sqrt(POP110) with 0.1, Pnorm for PRCL = sqrt(POP110) with 10,
MICH gain = -30, PRCL gain = 8), and then exciting each relevant optic, one at a time, in yaw. The excitation was always using the ASCYAW excitation |
|
Tue May 21 14:50:52 2013, Max Horton, Update, , Importing New Code
|
There was an issue with running the new summary pages, because laldetchar was not included (the website I used for instructions doesn't mention that
it is needed for the summary pages). I figured out how to include it with help from Duncan. There appear to be other needed dependencies, though.
I have emailed Duncan to ask how these are imported into the code base. I am making a list of all the packages / dependencies that I needed that |
|
Wed Jun 5 14:39:41 2013, Max Horton, Update, , Importing New Code
|
Most dependencies are met. The next issue is that matplotlib.basemap is not installed, because it is not available for our version of python.
We need to update python on megatron to fix this. |
|
Thu Jun 27 05:44:51 2013, rana, Update, , 40MARS wireless network problems
|
Quote:
I'm not sure what's going on today but we're seeing ~80% packet loss on the 40MARS wireless network. This is obviously causing big |
|
Fri Jun 28 11:33:32 2013, Steve, Update, , 40MARS wireless network problem
|
Quote:
I'm not sure what's going on today but we're seeing ~80% packet loss on the 40MARS wireless network. This is obviously causing big |
|
Wed Jul 3 11:07:17 2013, Alex, Summary, , Photodetector Characterization
|
[Alex, Koji]
We characterized Koji's BBPD MOD for REFL165 (see attachment).
First, we calibrated the Agilent 4395 Network Analyzer (NA) to account for differences in cable features between the Ref PD and Test PD connections. |
|
Mon Jul 8 16:27:49 2013, Alex, Update, , Planned rack additions
|
Alex and Eric
For the photodetector frequency response automation project, we plan to add modules to rack 1y1 as shown in the attached picture (Note: boxes are
approximately to scale). |
|
Thu Jul 11 12:00:50 2013, Alex, Update, , Planned rack additions
|
[Eric, Alex]
We mounted our Laser Module and Laser Power Source in rack 1y1. We plan to add our RF Switch and Transformer Module to the rack, as pictured. (Note:
drawn-in boxes in picture are approximately to scale.) Note that the panel of knobs which the gray boxes overlap is obsolete and will soon be removed. |
|
Thu Jul 11 23:50:57 2013, gautam, Configuration, , PZT Driver Board-changes made
|
Summary:
Continued with tests on the PZT driver board. I made a few changes
to replace defective components and also to modify the gain of the HV amplifier stage. I believe the board has been verified to be satisfactory, and is |
|
Mon Jul 15 16:51:37 2013, Alex, Configuration, , Planned AS Table addition
|
[Eric, Alex]
We are planning to add our reference PD to the southern third of the AS Table as pictured in the attachment. The power supply will go under the
table. |
|
Tue Jul 16 10:16:23 2013, Koji, Update, , Beatbox XARM whitening modified
|
The X arm whitening filters of the beatbox were modified.
Now we have about 10 times better floor level above 100Hz and ~3 better at 1Hz.
- The previous whitening was zero@1Hz, pole@10Hz, and the DC gain of the unity. |
|
Tue Nov 12 21:50:01 2013, rana, Update, , zita network configured
|
I installed 'nfs-client' on zita (the StripTool terminal). It now has mounted all the shared disks, but still can't do StripTool since its
a 32-bit machine and our StripTool is 64. |
|
Fri Oct 31 11:46:15 2014, manasa, Update, , Rattling HEPA : Eventually stops
|
The PSL HEPA stopped working while it was running at 80%.
I have closed the PSL enclosure.
Steve is working to fix this. |
|
Tue Jul 7 17:22:16 2015, Jessica, Summary, , Time Delay in ALS Cables
|
I measured the transfer functions in the delay line cables, and then calculated the time delay from that.
The first cable had a time delay of 1272 ns and the second had a time delay of 1264 ns.
Below are the plots I created to calculate this. There does seem to be a pattern in the residual plots however, which was not expected. |
|
Fri Jul 29 03:44:04 2016, Aakash, Summary, , About Acromag | SURF 2016
|
I tried to recompile the modbusApp binary for linux-arm acrhitecture since I suspected someting wrong with it. But still the problem persists; I can
connect to acromag but cannot access the channels. I have also reconfigured new acromag bus works terminal XT 1221-000 and I want to test if I could access
its channels. My target is to complete this acromag setup work before sunday morning so that I can focus towards having some useful results for my presentation. |
|
Mon Feb 13 17:19:41 2017, yinzi, Configuration, , configuring ethernet for raspberry pi
|
Gautam and I were able to get the Raspberry Pi up and running today, including being able to ssh into it from the control room.
Below are some details about the setup/procedure that might be helpful to anyone trying to establish Ethernet connection for a new RPi, or a
new operating system/SD card. |
|
Fri Apr 21 13:59:47 2017, Eric Gustafson, Summary, , 1064 nm Semiconductor Laser Fiber Distribution System and Mirror Tomography
|
1064 nm Semiconductor Laser Fiber Distribution System and Mirror Tomography
Below threshold these Semiconductor Fabry-Perot lasers have an axial mode structure with a spacing of about a THz. As you turn up the current
to above threshold the first mode to oscillate saturates the gain down on all the modes and only it oscillates. The laser I have here in my office |
|
Mon Mar 19 07:37:00 2018, Angelina Pan, Summary, , Proposed QPD Optical Arrangement
|
I am currently working on an optical arrangement consisting of a QPD that measures the fluctuations of an incoming HeNe laser beam that is reflected
by a mirror. The goal is to add a second QPD to the optical arrangement to form a linear combination that effectively cancels out the (angular)
fluctuations from the laser beam itself so that we can only focus on the fluctuations produced by the mirror. |
|
Thu Mar 22 17:47:16 2018, Angelina Pan, Summary, , Proposed QPD Optical Arrangement
|
| |
|
Mon Jun 4 19:41:01 2018, keerthana, Update, , Finesse code for cavity scan
|
The cavity scan data obtained from the Finesse simulation is attached here. Fig1 indicates the cavity scan data in the absence of induced misalignment.
In that case only the fundemental mode is resonating. But when a misalignment is induced, higher order modes are also present as seen in Fig2. This is
in the absence of surface figure error in the mirrors. Now I am trying to provide perturbations to the mirror surface in the form of zernike polynomials |
|
Thu Jun 7 20:19:53 2018, pooja, Update, ,
|
| Just to inform, I'm working in optimus to develop python code to train the neural network since it requires a lot of memory. |
|
Wed Jun 13 18:08:36 2018, keerthana, Update, , Finesse code for cavity scan
|
The unit mentioned in the x-axis was wrong. So I have remade the graphs. The point where frequency equals to zero is actually the frequency corresponding
to the laser, which is in the range of 1014 Hz and it caliberated as zero.
Quote:
|
|
Thu Jun 21 09:33:02 2018, Jon, Update, , AUX Mode Scans of YARM, PRC cavities
|
[Jon, Keerthana, Sandrina]
Yesterday we carried out preliminary proof-of-concept measurements using the new AS-port-injected AUX laser to resolve cavity mode resonances.
At the time we started, I found the beat note levels consistent with what Johannes had reported the night before post-realignment. Hence we did |
|
Fri Jun 22 10:42:52 2018, pooja, Update, , Developing neural networks
|
Aim: To find a model that trains the simulated data of Gaussian beam spot moving in a vertical direction by the application of a sinusoidal signal.
All the attachments are in the zip folder.
The simulated video of beam spot motion without noise (amplitude of sinusoidal signal given = 20 pixels) is given in this link https://drive.google.com/file/d/1oCqd0Ki7wUm64QeFxmF3jRQ7gDUnuAfx/view?usp=sharing |
|
Sun Jul 8 22:27:25 2018, keerthana, Update, , AUX diagram
|
(Analisa, Keerthana, Sandrine)
So far we tried four different techniques to scan the AUX laser. They are,
1. Scanning the marconi frequency to sweep the central frequency of the AUX laser. |
|
Thu Jul 12 15:15:47 2018, Sandrine, Update, , Beat Note Measurements for Cavity Scans
|
(Gautam, Sandrine)
We calculated the expected power of the beat note for Annalisa's Y arm cavity scans.
Beat Note Measurement |
|
Sat Jul 28 22:16:49 2018, John Martyn, Update, , Characterization of Transimpedance Amplifier
|
Kevin and I meaured the transfer function of the photodiode circuit using the Jenne laser and agilent in the 40m lab. The attached figures depict
our measured transfer function over the modulation frequency ranges of 30kHz-30MHz and 1kHz-30MHz when the power of the laser was set to 69 and 95 μW.
These plots indicate a clear roll off frequency around 300 kHz. In addition, the plots beginning at 1kHz display unstable behavior at frequencies below |