I ran through the procedure to calibrate the lever arm of the Hartmann sensor. The beam from a 632.8nm HeNe laser was expanded to approximately 12mm diameter and injected into a Michelson interferometer. The Hartmann sensor was placed at the output port of the Michelson.
I ran a test of the HWS with the QFLD-950-3S for 5 days. The test was terminated as we need to disconnect all the cabling and tidy up all the computers in the lab.
9:40PM PDT - I've just restarted the long term measurement of the Hartmann sensor noise with the QFLD-950-3S.
I've started a long-term measurement of the HWS fiber-launcher. I'm interested in seeing how stable the output is. The HWS is currently running in the following configuration:
The HWS is currently running at 57Hz. The HWS code is running on HWS (10.0.1.167). It is the same as the site code with some modifications to determine information about the Gaussian beam envelope. The following data is written to file on the HWS machine in files containing 10,000 cycles. Each cycle (or row) the following data is recorded:
These are saved to files on the HWS machine: ~/framearchive/C4/HWSlongterm/<GPSTIME>_CIT_HWS.txt
The data from the long-term measurement of the HWS is presented here. The beam envelope moves by, at most, about 0.3 pixels, or around 3.6 microns. The fiber-launcher is about 5" away from the HWS. Therefore, the motion corresponds to around 30 micro-radians (if it is a tilt). The beam displacement is around 4 microns.
The optical properties change very little over the full 38 days (about 2 micro-radians for tilt and around 2 micro-diopters for spherical power).
The glitches are from when the SLED drivers were turned off temporarily for other use (with the 2004nm laser).
Today I made the first characterization measurements of the mocked-up adaptive wavefront control system planned for the signal recycling mirrors.
Inside the light-tight enclosure on the center table, I've assembled and aligned a 10.2 micron CO2 projector which provides a heating beam of up to 150 mW incident on an SRM-like test optic. A co-aligned 633 nm probe beam and Hartmann wavefront sensor are used to measure the resulting thermal lens. I've written and installed new software on the machine hws (10.0.1.167) for viewing the wavefront distortion in real time, as shown in the below screenshot. This viewer is launched from the terminal via the command $stream_gradient_CIT
There is also a second utility program for displaying the raw Hartmann sensor CCD image in real time, which is useful for aligning the probe beam. It is launched by the terminal command $stream_intensity_CIT
Lens Formation Time Scale
First, I made a time-resolved measurement of the thermal lens formation on the test optic at maximum heating beam power (150 mW). The lens appears to reach steady-state after 30 s of heating. When the heating beam is turned off, the lens decays on a very similar time scale.
Lens Strength v. Incident Heating Power
Second, I measured the thermal lens strength as a function of incident heating beam power, which I measured via a power meter placed directly in front of the test optic. Below is the approximate maximum optical path difference induced at several heating beam powers.
The above optical path differences are approximate and were read-off from the live display. I recorded Hartmann sensor frame data during all of these measurements and will be analyzing it further.
There were known to be huge (65%) heating beam power losses on the SRM AWC table, somewhere between the CO2 laser and the test optic. Today I profiled the setup with a power meter, looking for the dominant source of losses. It turned out to be a 10" focusing lens which had the incorrect coating for 10.2 microns. I swapped this lens with a known ZnSe 10" FL lens (Laser Research Optics LX-15A0-Z-ET6.0) and confirmed the power transmittance to be >99%, as spec'd. There is now ~310 mW maximum reaching the test optic, meaning that the table losses are now only 10%.
Using a single-axis micrometer stage I also made an occlusion measurement of the heating beam radius just in front of the test optic. I moved the 10" focusing lens back three inches away from the test optic to slightly enlarge the beam size. In this position, I measure a beam radius of 3.5+/-0.25 mm at 1.5" in front of the test optic (the closest I can place the power meter). The test optic is approximately 20" from the 10" FL lens, so the beam has gone through its waist and is again expanding approaching the test optic. I believe that at the test optic, the beam is very close to 4 mm.
For archive purposes, attached is a write-up of all the HWS measurements I've made to date for the SRM CO2 projector mock-up.
We tested the output of the fiber launcher D1800125-v3. We were using a 6mm spacer in the SM1 lens tube and 11mm spacer in the SM05 lens tube and the 50 micron core fiber.
The output of the fiber launcher was projected directly onto the CCD. Images of these are attached (coordinates are in pixels where 100 pixels = 1.2mm)
There is a lot of high-spatial frequency light on the output. It looks like there is core and cladding modes in addition to a more uniform background. There was an indication that we could clear up these annular modes with an iris immediately after the fiber launcher but I didn't get any images. We're going to test this next week when we get an SM1 mountable iris.
And here's the output of the fiber launcher when I fixed it at 313mm from the camera, attached an iris to the front and slowly reduced the aperture of the iris.
The titles reflect the calculated second moment of the intensity profiles (an estimate of the equivalent Gaussian beam radius). The iris is successful in spatially filtering the central annular mode at first and then the outer annular mode.
We'll need to determine the optimum diameter to get good transmission spatially without sacrificing too much power.
Here is the output from D1800125-v5_SN01.
Title was wrong - this is actually config [12,2,4,125]
I'm considering the 86-711 2" 532nm PBS from Edmund Optics for the ETM HWS at the sites.
The effect on the transmission through the system, compared to the THorlabs PBS, is shown in the attached plot.
Conclusion: it looks almost as effective as the Thorlabs PBS with the added benefit of being 2" in diameter.
I changed the HWS code to the new git.ligo HWS version.
I've set up some symbolic links to these directories to mimic the old directory structure, so ..
contents of tcs_daq: /target/TCS_westbridge.db
hartmann had started responding to requests to log-in with the a request to change the password. Attempts to change the password proved unsuccessful. I tried to access the machine locally to change the password but I couldn't the display started, so I had to reboot it.
This attachment is a Shockwave Flash animation of the iLIGO ETM getting a 1 W beam with a 3.5 cm radius getting fully absorbed onto the surface at t = 0.
I added a workstation at 10.0.1.26 in the TCS lab.
I measured the reflectivity of a possible HWS replacement mirror at 532nm. Thorlabs BB2-EO3
Incident power = 1.28mW
Reflected power = 0.73mW
R = 56% at 45 degrees AOI.
The 400 mW CO2 laser on the Hartmann table is currently configured for a measurement of its relative intensity noise. It is aligned to a TCS CO2P photodetector powered by a dual DC power supply beside the light enclosure. I got some data last night with the laser current dialed back for low output power (0.5-10 mW incident), but still need to analyze it. In the meantime please don't remove parts from the setup, as I may need to repeat the measurement with better power control.
Attached for reference is the RIN measurement from the initial data.
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)
Mounted the f=8" lens (used a 2" pedestal) and placed it on the table so the image fit well on the CCD and so a sharp object in front of the lens resulted in a sharp image. The beam was clipping the f=4" lens (between gold mirror and test mirror) so I spent time moving that gold mirror and the f=4" lens around. I'll still need to finish up that setup.
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 for the CCD of the HWS. It seems that the f=8 lens can go about 6 inches from the test mirror, and an f ~ 2.3 (60 mm) lens can go about 2 inches in front of the CCD to give the appropriate beam size. However, the image doesn't seem very sharp.
The beam is also not hitting the CCD currently because of the increase in angle of incidence on the test mirror and limitations of the box. I'd like to move the HWS closer to the SLED (and will then have to move the SLED as well).
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.
At 64cm away, approximately 79000 saturated pixels and 1054 average value.
At 50cm away, approximately 22010 saturated pixels and 1076 average value.
Currently the setup is at 64cm. Could afford to be more magnified, so might want to move the f=60mm lens around. Also, if we're going to need to be able to access the HWS (i.e. to screw on the array) we might want to move to the 50cm location.
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.
We considered different possible mounts to use for the test optic, and decided to move it to a mount where there is less contact. The test optic was also moved closer to the HWS to achieve appropriate beamsize on the optic coming from the mode-matching telescope.
The f=200 lens is now approximately 2/3 of the distane from the test optic to the HWS, resulting in an appropriately sized beam at the HWS.
Current was also turned down to achieve 0 saturated pixels.
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). We want to put it on the side of Al if possible.
Bonded a mirror (thickness ~6 mm) to aluminum disk (thickness ~5 mm) and it's still curing.
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.
I also plotted the best-fit defocus for each temperature from COMSOL (Temperature vs. Defocus), and looking at values from HWS it seems that we're off by a normalization factor of approx. 4.
Caltech Facilities has determined that the walls in the SE corner of the TCS Lab in West Bridge were water damaged during last weekend’s rain. They are going to remove the plaster from the walls and dehumidify the area for a week or so. All tables in the room are going to be covered with plastic for this process. In the short term I’ve shutdown all the equipment in the lab (including FB4). The 2-micron cavity-testing fabrication has been moved next door to the QIL.
I drew up one way we could set up the three available bake ovens in the TCS lab on the single oil pump.
If this looks feasible to others, we can move the ovens into the TCS lab. Duo and I will be occupied at KNI during Tuesday and Monday morning, so the usual lab cleanup time may not be the best. Perhaps Monday afternooon we can at least get the ovens out of the hallway and get one of them set up for baking.
My preference is to have tubes back towards the wall where possible. We might be able to drill a large diameter hole in the table top to accommodate them.
We have to get confirmation that the exhaust can be extracted - otherwise this whole thing is moot.
Aidan and I continued the lab clean-up today. There's still more to do, but we did fully clear the large optical table which formerly housed the 50 W CO2 laser. I moved the optical enclosure over from the small table to serve as the area for the point absorber experiment. Inside it I mounted the Hartmann sensor and a 532 nm Thorlabs LED source. The LED still needs collimating/focusing optics to be installed.
Small/Medium size gloves need to be ordered in order to handle the optics carefully.
New gloves are ordered for the TCS and QIL labs. They arrive tomorrow (Friday).
Facilities came in on Friday and teed off a new duct to provide exhaust for the proposed new vacuum bake area in the TCS Lab. Photos are attached.
We installed a plastic sheet between the work area and the rest of the lab (the rest of the lab was overpressurized relative to the work area). Also, they use a vacuum when doing any drilling.
I cleaned up the HWS table in preparation for replacement with the 4x10 table. We still need to move the cabinet and get the enclosure out of the way.
Yesterday, I installed CentOS 5.3 on the Gateway GT5482 machine that housed the EDT frame-grabber.
> yum install gcc
> yum install make
> yum install tk
> yum install kernel
I tried to run ~/fgdriver/linux.go at this point to install the EDT driver, but the installation failed about halfway through with the message "problem making the driver module". An investigation revealed that this was the due to the failure of ~/fgdriver/linux/module/makefile. I tried running that makefile separately to build the driver module and it crashed with the message: Can't find /lib/modules/2.6.18-128.el5/source/include/linux/mm.h. I concluded that the kernel source code wasn't installed
> yum install kernel-devel
> yum install kernel-xen-devel
And then I followed the instructions at the link: http://wiki.centos.org/HowTos/I_need_the_Kernel_Source
from: > yum install rpm-build redhat-rpm-config unifdef
to: > rpm -i http://mirror.centos.org/centos/5/updates/SRPMS/kernel-2.6.18-164.15.1.el5.src.rpm 2>&1 | grep -v mockb
and at the latter point the rpm build pissed and moaned that it couldn't find the file kernel-2.6.18-164.15.1.el5.src.rpm
However, some combination of the above must have worked. I rebooted the computer and logged in again as root. At this point the install script ~/fgdriver/linux.go ran from start to finish without complaining. A quick test of the resulting /opt/EDTpdv/camconfig and then /opt/EDTpdv/serial_cmd showed that I could access the Dalsa 1M60 camera through the frame grabber.
Regarding the installation of EDT software, I overlooked a note from the install.pdf file.
The gist of it is that if the scripts do not run, then remount the CD-ROM by typing the
mount /mnt/cdrom -o remount,exec
which will then allow the scripts to be run. The directory /mnt/cdrom should be changed if
the cdrom is mounted somewhere else. (The note can be found in the page 1 of the file
Unfortunately I don't have linux installed at the moment so I cannot test this. My computer was
reinstalled with Windows XP, the previous CentOS system being wiped out. However if this works,
then there is probably no need to copy the files to the hard drive.
I saw this and tried it when i was installing, but I had more flexibility when I copied the files directly to the hard drive.
I noticed that when i ran /opt/EDTpdv/camconfig and selected camera 331, which appeared to be closest to the Dalsa Pantera 1M60 camera, the software loaded the configuration file pantera11m4fr.cfg.
I tried to locate which entry in the camconfig list corresponded to the dalsa_1m60.cfg configuration file, but none of them seemed to. I couldn't select any entry and get it to report that it was using the 1m60 config file.
Next I noticed that there were 659 configuration files in the /opt/EDTpdv/camera_config directory but only 460 configuration options in camconfig. This seemed like 1/3 of the config files were somehow not formatted correctly, including,possibly the 1M60 config file.
By editing the pantera11m4fr.cfg I verified that the name of the camera, as it appears in the camconfig program, is the second line in the configuration file. For that file it was:
# CAMERA_MODEL "Dalsa Pantera 12 bit single channel camera link"
where the first line is just a single hash. The dalsa_1m60.cfg file did not have a name formatted in the same way as above: it was originally as shown below:
# Dalsa 1m60 config file (freerun)
so i changed the name in that configuration file to the following and it was suddenly available in the list when ./camconfig was run
# CAMERA_MODEL "Dalsa 1m60 config file (freerun)"
I selected that camera (number 53 in the list). Once this was done I ran pdv_flshow/pdvshow again the image that was displayed from the camera appeared to be correctlty demodulated.
Actually, the very first time i ran pdvshow the image was demodulated correctly but it appeared that the origin was offset and then the image wrapped around a little at the edges. However, every successive time I've run pdvshow since then I've had a perfectly demodulated image.
I ran some test patterns by changing the video mode using the serial communications menu in the camera. I also illuminated the Hartmann sensor with a torch/flashlight and got some spot patterns - see attached images.
Also, I've attached the dalsa_1m60.cfg file.
This is an amended version of simple_take.c.
The files below are all in the directory /opt/EDTpdv/hartmann/src
The new machine in the TCS lab is running Ubuntu. I installed the frame-grabber into it and, after loading the configuration file for the camera, was able to access the serial port on the camera and also was able to record a properly formatted image from the Hartmann sensor.
I fixed a bug in how the raw Mako CCD camera images are being read into memory. The bmp files turn out to have a block memory layout that broke my in-place reader.
Koji: QIL/TCS entrance flooding. Check your lab
Anchal: Can someone take a look at CTN too?
Koij: TCS needs more people @aidan
Koji: CTN ok
Aidan: On my way
Shruti: Cryo seems fine
Aidan: There was a leak in a pipe in the wall of B265A. It was coming from the building air conditioner condensation overflow. Facilities has fixed the pipe and is working on clean-up
I checked the lab this morning. It was dry and there wall was in the same state as yesterday.
The carpentry shop removed wet plaster sections from the wall following the flood (process was gentle scraping of wet plaster flakes, supervised by me). The wet section of wall needs a few days to dry and then they will plaster and paint it.
11:29AM - Lab has flooded again this morning. I'm calling PMA. Looks to be the same issue as before.
Some photos of water and clean-up.
Summary: I came into the lab around 11:30AM and found water on the floor in the changing room outside QIL/TCS. Turns out the condesation overflow pipe from the AC blew out again. This time near the ceiling. Water was on the floor but also had sprayed a little onto the tool chest and East optical table. A few optics got wet on the table. Initial inspection looks like electronics were spared with the exception of the "broken" spectrum analyzer that was on the floor.
Facilities came in and cleaned up the water. A small amount got into QIL but stayed near the door as the lab floor slopes up from the door area. They fixed the pipe and were looking into whether there was a blockage cuasing this problem. PMA was notified and John Denhart is coordinating follow-up.
Triage effort: given the AC was still active, John and I strung a temporary tarp across the two tables to block any spray.
I labelled and strung 8 of the 16 custom 40' BNC cables from L-Com between the HWS table and the BNC feed-through on the rack. Each cable is labelled HWS TABLE CHxx where 01<= xx <= 08. I'm going to leave the other 8 until we have room in the BNC feedthrough on the rack.