 Thu Jun 17 22:03:51 2010, James K, Misc, Hartmann sensor, SURF Log -- Day 2, Getting Started
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For Thursday, June 17:
Today I attended a basic laser safety training orientation, the second Introduction to LIGO lecture, a Summer Research Student Safety Orientation,
and an Orientation for Non-Students living on campus (lots of mandatory meetings today). I met with Dr. Willems and Dr. Brooks in the morning and went |
Sat Jun 19 17:31:46 2010, James K, Misc, Hartmann sensor, SURF Log -- Day 3, Initial Image Analysis 7x
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For Friday, June 18:
(note that I haven't been working on this stuff all of Saturday or anything, despite posting it now. It was getting late on Friday |
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Tue Jun 22 00:21:47 2010, James K, Misc, Hartmann sensor, Surf Log -- Day 4, Hartmann Spot Flickering Investigation 7x
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I started out the day by taking some images from the CCD with the
OLED switched off, to just look at the pattern when it's dark. The images looked like this:
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Tue Jun 22 22:30:24 2010, James K, Misc, Hartmann sensor, SURF Log -- Day 5, more Hartmann image preliminary analysis 13x
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Today I spoke with Dr. Brooks and got a rough outline of what my experiment for the next few weeks will entail. I'll be getting more of the details
and getting started a bit more, tomorrow, but today I had a more thorough look around the Hartmann lab and we set up a few things on the optical table.
The OLED is now focused through a microscope to keep the beam from diverging quite as much before it hits the sensor, and the beam is roughly aligned to |
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Wed Jun 23 22:57:22 2010, James K, Misc, Hartmann sensor, SURF Log -- Day 6, Centroiding 10x
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So in addition to taking steps towards starting to set stuff up for the experiment in the lab, I spent a good deal of the day figuring out how
to use the pre-existing code for finding the centroids in spot images. I spent quite a bit of time trying to use an outdated version of the code that didn't
work for the actual captured images, and then once I was directed towards the right version I was hindered for a little while by a bug. |
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Fri Jun 25 00:11:13 2010, James K, Misc, Hartmann sensor, SURF Log -- Day 7, SLED Beam Characterization
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BACKGROUND:
In order to conduct future optical experiments with the SLED and to be able to predict the behavior of the beam as it propagates across the |
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Thu Jul 15 20:06:37 2010, James K, Misc, Hartmann sensor, SURF Log: Thermally Induced Defocus Experiments
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A quick write-up on recent work can be found at: Google
Docs
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Mon Jul 26 18:47:12 2010, James K, Misc, Hartmann sensor, Hex Grid Analysis Errors and Thermal Defocus Noise
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My previous eLog details how the noise in Hartmann Sensor defocus measurements appears to vary with ambient light. New troubleshooting analysis reveals
that the rapid shifts in the noise were still related to the ambient light, sort of, but that ambient light is not the real issue. Rather, the noise
was the result of some trouble with the centroiding algorithm. |
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Tue Dec 29 16:05:09 2009, Frank, Computing, DAQ, booting VME crates from fb1
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| http://nodus.ligo.caltech.edu:8080/AdhikariLab/514 |
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Mon Jul 22 18:44:53 2019, Edita Bytyqi, Things to Buy, General, Need to Order Gloves
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| Small/Medium size gloves need to be ordered in order to handle the optics carefully. |
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Mon Jul 22 18:46:23 2019, Edita Bytyqi, Lab Infrastructure, , Laser-Lens-HWS Setup
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Today, I set up a system consisting of the 520 nm laser, a 2'' mirror and two lenses of focal lengths f1 = 40 cm and f2 = 20 cm. The goal was
to collimate the beam coming from the laser, so it goes parallel through the test optic at a radius of ~2.5 cm and then focus it to a radius of ~
1.2 cm to fit the CCD dimensions of the HWS. The mirror was placed about 1 cm close to the laser and the first lens is setup at a distance~f1=40cm from |
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Wed Jul 24 16:25:13 2019, Edita Bytyqi, Lab Infrastructure, Optics, Updated 2-lens setup
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The previous 2-lens setup focused the beam to a tight spot, however due to the divergence angle of the laser beam, a significant amount of power was
not being captured by the fiirst lens at a distance of 40 cm from the source. The divergence angle seems to be bigger than 0.06 by a factor of 2, so a
f = 20 cm lens was used to collimate the beam and a f = 30 cm lens was used to focus it. A mirror was used to reflect the beam, so we obtain steering control. |
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Mon Jul 29 18:53:16 2019, Edita Bytyqi, Lab Infrastructure, Optics, Mounted Reflector and Heater
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Since we set up the 2-lens system focusing the laser beam to the CCD, the next step was to mount the spherical reflector (31 mm wide) and the heater
(~3 mm diameter). I used a small 3-axis stage to mount the heater, providing 3 degrees of freedom that would allow to manipulate the height of the heater,
its position with respect to the reflector (left-right and in-out). The reflector was mounted in such a way that we can control its rotation angle, height |
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Thu Aug 1 15:20:39 2019, Edita Bytyqi, Lab Infrastructure, Optics, Reflector Mount and DC Supply
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Yesterday, we were able to take some data using the 120 V DC power supply. The reflectors cut at the focal point and radius were both tested; the semi-circle
cut proved to give a better focus, likely because roughly half the heat is lost using the focal-point reflectors. For upcoming tests, the semicircle reflectors
will be used. We varied the surface shine by using the dull and reflective side of Al foil, as well as using the machined Al itself. The best result was |
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Mon Aug 12 21:15:12 2019, Edita Bytyqi, Electronics, , Determining heater/reflector focus
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I took images of the heat pattern projected on a piece of paper produced by the semi-circle reflector. I used 108V to drive current throught he
heater. I tested the reflector without any coating and then with the dull and shiny sides of Al foil. I wasn't able to test the focal-point cut reflector
because I had to glue a screw to it with epoxy which cures overnight. I will do these measurements tomorrow. Figure 2 shows the setup I used to get |
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Fri Aug 16 17:05:14 2019, Edita Bytyqi, Electronics, , FLIR Images of new reflector focusing heat
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We got 11 new semi-circle cut reflectors of radius ~3.6 cm. I glued a screw to the back of one reflector using the same epoxy as for the previous reflectors.
Due to the bigger ROC of the reflector, a tight focus is achievable at greater distances (~15 cm). |
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Thu Feb 24 10:23:31 2011, Christopher Guido, Laser, Laser, LTG initial noise
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Cheryl Vorvick, Chris Guido, Phil Willems
Attached is a PDF with some initial noise testing. There are 5 spectrum plots (not including the PreAmp spectrum) of the laser. The first two are
with V_DC around 100 mV, and the other three are with V_DC around 200 mV. (As measured with the 100X gain preamplifier, so ideally 1 and 2 mV actual) We |
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Tue Jul 10 17:49:13 2018, Aria Chaderjian, Laser, General, July 10, 2018
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Went down to the lab and showed Rana the setup. He's fine with me being down there as long as I let someone know. He also recommended using an adjustable
mount (three screws) for the test mirror instead of the mount with top bolt and two nubs on the bottom - he thinks the one with three screws as constraints
for the silica will be easier to model (and be more symmetric constraints) |
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Thu Jul 12 18:48:21 2018, Aria Chaderjian, Laser, General, July 12, 2018
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The beam reflecting off the test mirror was clipping the lens between gold mirror and test mirror, so I reconfigured some of the optics, unfortunately resulting
in a larger angle of incidence.
From the test mirror, the beam size increases much too rapidly to fit onto the 2-inch diameter lens with f=8 that was meant to resize the beam |
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Fri Jul 13 16:42:50 2018, Aria Chaderjian, Laser, General, July 13, 2018
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The table is set up. The HWS and SLED were moved slightly, and a minimal angle between the test mirror and HWS was achieved.
There are two possible locations for the f=60mm lens that will achieve appropriate magnification onto the HWS: 64cm or 50 cm from the
f=200mm lens. |
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Mon Jul 23 10:04:19 2018, Aria Chaderjian, Laser, General, July 20, 2018
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With Jon's help, I changed the setup to include a mode-matching telescope built from the f=60mm (1 inch diameter) lens and the f=100mm lens. These
lenses are located after the last gold mirror and before the test optic. The height of the beam was also adjusted so that it is more centered on these
lenses. Note: these two lenses cannot be much further apart from each other than they currently are, or the beam will be too large for the f=100mm lens. |
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Tue Jul 24 16:52:44 2018, Aria Chaderjian, Laser, General, July 23, 2018 and July 24, 2018
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Attached the grid array of the HWS.
Applied voltage (5V, 7V, 9.9V, 14V) to the heater pad and took measurements of T and spherical power (aka defocus).
The adhesive of the temperature sensor isn't very sticky. The first time I did it it peeled off. (Second time partially peeled off). |
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Fri Aug 3 15:46:12 2018, Aria Chaderjian, Laser, General, August 3, 2018
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To the best of my ability, calculated the magnification of the plane of the test optic relative to the HWS (2.3) and input this value.
Increased the temperature slightly and saved data points of defocus to txt files when temperature leveled out. This was a slow process, as it
takes a while for things to level out. I only got up to about 28.5C, and will need to continue this process. |
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Tue Jun 5 17:25:43 2012, Alex Mauney, Misc, aLIGO Modeling, 6/5/12 Daily Summary
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- Had a meeting to talk about the basics of LIGO (esp. TCS) and discuss the project
- Created COMSOL model for the test mass with incident Gaussian beam.
- Added a ring heater to the previous file |
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Wed Jun 6 16:54:09 2012, Alex Mauney, Misc, aLIGO Modeling, 6/6/12 Daily Summary
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- Got access to and started working with SIS on Rigel1
- Fixed SVN issues
- Refined COMSOL model parameters and worked on a better way to implement the heating ring to get the astigmatic heating pattern. |
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Thu Jun 7 16:50:16 2012, Alex Mauney, Misc, aLIGO Modeling, 6/7/12 Daily Summary
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- Created a COMSOL model with thermal deformations
- Added non-symmetrical heating to cause astigmatism
- Worked on a method to compute the optical path length changes in COMSOL |
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Fri Jun 8 16:36:47 2012, Alex Mauney, Misc, aLIGO Modeling, 6/8/12 Daily Summary
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- Tried to fix COMSOL error using the (ts) module, ended up emailing support as the issue is new in 4.3
- Managed to get a symmetric geometric distortion by fixing the x and y movements of the mirror to be zero (need to look for a better way to do
this as this may be unphysical) |
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Mon Jun 11 17:11:01 2012, Alex Mauney, Misc, aLIGO Modeling, 6/11/12 Daily Summary
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- Fixed the (ts) model, got strange results that indicate that the antisymmetric heating mode is much more prominent than previously thought
- Managed to get COMSOL data through matlab and into SIS
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Wed Jun 13 16:36:14 2012, Alex Mauney, Misc, aLIGO Modeling, 6/12 and 6/13 Daily Summary
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- Realized that the strange deformations that we were seeing only occur on the face nearest the ring heater, and not on the face we are worried about
(the HR face)
- Read papers by Morrison et al. and Kogelnik to get a better understanding of the mathematics and operations of the optical cavity modeled in |
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Thu Jun 14 16:51:03 2012, Alex Mauney, Misc, aLIGO Modeling, 6/14/12 Daily Summary
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- Plugged the output of the model with uniform heating into SIS using both modification of the radius of curvature, and direct importation of deflection
data
- Generated a graph for asymmetric heating and did the same |
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Mon Jun 18 16:30:36 2012, Alex Mauney, Misc, aLIGO Modeling, 6/18/12 Daily Summary
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- Verified that the SIS output does match satisfy the equations for Gaussian beam propagation
- Investigated how changing the amount of data points going into SIS changed the output, as well as how changes in the astigmatic heating effect
the output |
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Tue Jun 19 16:24:52 2012, Alex Mauney, Misc, aLIGO Modeling, 6/19/12 Daily Summary
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- Did more modeling for different levels of heating and different mesh densities for the SIS input.
- Lots of orientation stuff
- Started on progress report. |
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Wed Jun 20 16:44:58 2012, Alex Mauney, Misc, aLIGO Modeling, 6/20/12 Daily Summary
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- Attended a lot of meetings (Safety, LIGO Orientation)
- Finished draft of week 3 report (images attached)
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Thu Jun 21 16:54:45 2012, Alex Mauney, Misc, aLIGO Modeling, 6/21/12 Daily Summary
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- Paper edits and more data generation for the paper (lower resolution grid data)
- Attended a talk on LIGO
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Wed Jun 27 16:43:56 2012, Alex Mauney, Misc, aLIGO Modeling, 6/27/12 Daily Summary
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Plan for building the model
- Find the fields that would be incident on the beam splitter from each arm (This is done already)
- Propagate these through until they get to the OMC using the TELESCOPE function in SIS |
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Thu Jun 28 16:27:37 2012, Alex Mauney, Misc, aLIGO Modeling, 6/28/12 Daily Summary
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- Finished the MatLab code that both combines two fields and simulates the adjustment of the beamsplitter to minimize the power out (with a small offset).
- Added the signal recycling telescope to the SIS code that generates the fields
To Do: Make the OMC cavity in SIS |
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Mon Jul 9 16:54:17 2012, Alex Mauney, Misc, aLIGO Modeling, 7/9/12 Summary
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Made a COMSOL model that can include CO2 laser heating, self heating, and ring heating
Figured out how to run SIS out of a script and set up commands to run the two SIS stages of the model |
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Mon Apr 25 16:28:27 2011, Aidan, Joe, Computing, Network architecture, Fixed problem network drive fb1:/cvs on Ubuntu & CentOS machines
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With Joe's help we fixed the failure of princess_sparkle to mount the fb1:/cvs directory when relying on /etc/fstab.
First we changed the mounting options in fstab to the following:
fb1:/cvs /cvs nfs |
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Wed Aug 4 09:57:38 2010, Aidan, James, Computing, Hartmann sensor, RMS measurements with Hartmann sensor
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[INCOMPLETE ENTRY]
We set up the Hartmann sensor and illuminated it with the output from the fiber-coupled SLED placed about 1m away. The whole arrangement was covered
with a box to block out ambient light. The exposure time on the Hartmann sensor was adjusted so that the maximum number of counts in a pixel was about |
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Fri Nov 6 20:09:47 2009, Aidan, Laser, Laser, Test
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| Does this work? |
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Mon Dec 28 14:48:29 2009, Aidan, Computing, DAQ, VME crate has a "new" CPU - needs to be configured
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I installed a recycled VME crate in the electronics rack. It currently has a Baja 4700E CPU card in it - and this needs to be configured. We also have
the following cards, which are not plugged in right now.
1. ICS-110A-32 Analogue-to-Digital Converter - the jumpers need to be set on this to give it a unique memory address in the VME bus. |
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Tue Dec 29 17:50:57 2009, Aidan, Computing, DAQ, VME crate has proper boot settings
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| We fixed the start-up settings on the VME crate to look for a TCS startup file on fb0. The settings on the Baja 4700 are now: |
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Fri Jan 29 10:02:15 2010, Aidan, Computing, DAQ, New DAQ ordered
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On the advice of Ben Abbott, I've ordered the Diamond Systems Athena II computer w/DAQ, as well as an I/O board, solid state disk and housing for
it. The delivery time is 4-6 weeks.
Diamond Systems Athena II |
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Thu Feb 4 14:05:59 2010, Aidan, Electronics, Ring Heater, Ring heater transfer function measurement 240mHz-5Hz
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I've been trying to measure the ring heater transfer function (current to emitted power) by sweeping the supply voltage and measuring the emitted power
with a photodector positioned right next to the ring heater.
Last night the voltage was sweeping with a 1000mV setting on the SR785 which was fed into the Voltage Control of the Kepco Bipolar Operational |
 Thu Feb 4 15:26:37 2010, Aidan, Electronics, Ring Heater, Ring heater transfer function measurement 240mHz-5Hz
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Quote:
I've |
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Thu Feb 4 19:45:56 2010, Aidan, Misc, Ring Heater, Ring heater transfer function - increasing collection area
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I mounted the thinner Aluminium Watlow heater inside a 14" long, 1" inner diameter cylinder. The inner surface was lined with Aluminium foil
to provide a very low emissivity surface and scatter a lot of radiation out of the end. ZEMAX simulations show this could increase the flux on a PD by
60-100x. |
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Mon Feb 8 17:44:38 2010, Aidan, Electronics, Pre-amplifier, replace Pot with fixed Resistor
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Quote:
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Thu Feb 11 18:04:08 2010, Aidan, Laser, Ring Heater, Ring heater time constant
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I've been looking to see what the time constant of the ring heater is. The attached plot shows the voltage measured by the photodiode in response to
the heater turning on and off with a period of 30 minutes.
The time constant looks to be on the order of 600s. |
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Thu Feb 11 21:46:23 2010, Aidan, Electronics, Ring Heater, Ring heater time constant measurement - start time
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After leaving the ring heater off for several hours I turned on a 40V, 0.2A supply at a gps time of 949 988 700
The channel recording the PD response is C2:ATF-TCS_PD_HGCDTE_OUT.
However, there is a delay between the time at which something is supposed to be recorded and the time at which it is recorded. I looked |
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Fri Feb 12 11:39:28 2010, Aidan, Electronics, Ring Heater, Ring heater transfer function
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I applied a step function to the silver WATLOW heater and measured the response with the photodiode. The power spectrum of the derivative of the PD response
is attached. The voltage isn't calibrated, but that's okay because right now we're just interested in the shape of the transfer function. It looks like
a single pole around 850uHz. The noise floor is too great above 4 or 5 mHz to say anything about the transfer function. |