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ID Date Author Type Category Subject Text   1   Wed Jul 11 23:01:01 2012 janosch Optics Characterization starting the multi-color scatter experiment Steve Maloney, a visiting highschool teacher, and I have started to set up a new scattering experiment in the Richter lab. The idea is      2   Fri Jul 13 10:34:35 2012 janosch Optics Characterization camera image We were confused a bit about how the camera image changes when you move the arm that holds the camera and lens around the      3   Fri Jul 13 20:53:35 2012 janosch Optics Characterization two images The following two pictures were taken from the same angle with green (left) and red (right) incident laser at an angle of 15deg      4   Tue Jul 17 18:32:11 2012 janosch Optics Characterization purple images We have the new 405nm laser pointer.  The image to the left shows the scattered light from the red laser, the image to the      5   Wed Jul 18 18:43:34 2012 janosch Optics Characterization gone with the wind Here a little purple video. It starts with scattering angle around 15deg and stops at about 80deg.       6   Fri Jul 20 18:35:42 2012 janosch Optics Characterization purple improvements and first uncalibrated BSDF curves Today we improved alignment of the lens-camera arm. We discovered earlier that this alignment affects the amount of "snowfall"      7   Tue Jul 24 10:59:59 2012 janosch Optics Characterization sum of purple and red We played around with Matlab today. The first step was to convert light wavelengths into RGB colors. In this way we can combine      8   Fri Oct 12 16:23:20 2012 janosch Optics Daily Progress reassembled setup Nothing has happened since Steve, the visiting highschool teacher, has left. Meanwhile, some parts of the multi-color BRDF setup      16   Fri May 20 15:18:58 2016 Gabriele Optics Design Optical levers layout Attached a first layout of the optical lever systems. The beam spot radius on the QPD is about 0.8 mm, and the lever arm length      17   Sun May 22 23:40:45 2016 Gabriele Optics Design Optical levers layout An improved design is attached. I modified the input telescope to avoid using shor focal length lenses, to make it less critical,      23   Thu Jun 16 00:47:42 2016 Gabriele Optics Daily Progress Quality factor measurement of a Mark Optics disk at LMA [Massimo Granata (LMA), Quentin Cassar (LMA), Gabriele]  This week I'm visiting LMA      51   Mon Jul 18 18:05:46 2016 Gabriele Optics Daily Progress Optical setup Small modifications to the optical setup: added a 1m focal lenght lens (AR coated for 1064nm...) right before      60   Mon Jul 25 15:35:31 2016 Gabriele Optics Characterization Calibration of the QPD in physical units The equations below are wrong. Please refer to https://nodus.ligo.caltech.edu:8081/CRIME_Lab/116      91   Fri Aug 19 19:05:01 2016 Gabriele Optics Daily Progress Disk installed into the chamber I assembled the disk suspension sytem and installed into the chamber. Although I don't have the magnets and coils, I installed the  10x    95   Sun Aug 21 13:45:56 2016 Gabriele Optics Daily Progress Wierd behavior of ring downs and Improved setup The last two ring downs I measured today showed a weird behavior of the lowest modes:      101   Mon Aug 22 16:59:13 2016 Gabriele, Alastair Optics Daily Progress Laser polishing of the disk edges We set up a test facility for laser polishing the disk edges, using the CO2 laser in the TCS laboratory. We focused the beam with      105   Thu Sep 1 02:13:33 2016 Gabriele Optics Characterization Expected frequencies for the 75 mm disks with flats Here are the nominal parameters of the disk with flats      116   Tue Sep 20 15:34:00 2016 Gabriele Optics Daily Progress Improved optical lever layout Goal Improve the optical setup, by increasing the response of the QPD to disk motion.      122   Thu Sep 22 13:39:40 2016 Gabriele Optics Configuration Updated design for the new C.Ri.Me. setup Today I measured the amount of space available on the table for the new (4-fold) C.Ri.Me. setup. It's 1050 x 1220 mm, with the      127   Mon Sep 26 15:59:09 2016 Gabriele Optics Daily Progress QPD auto centering We have a few motorized mounts (with New Focus picomotors) and one controller (an old New Focus 8753, six axis total) that      132   Thu Sep 29 15:40:45 2016 Gabriele Optics Design Beam profile of new 21mW HeNe laser and tweak of optical lever design I measured the beam profile of the new Thorlabs HeNe (21.8 mW measured). The beam waist is 355 microns, very close to the laser      270   Fri Jan 20 17:20:20 2017 Gabriele Optics Daily Progress Input part of the optical lever setup installed and aligned Today I installed and aligned part of the optical components for the optical lever of the new setup. For the moment being I      272   Mon Jan 23 16:29:52 2017 Gabriele Optics Daily Progress Input part of the optical lever setup installed and aligned Today I cabled and installed the four QPD, in a temporary position. I also assembled four picomotor mounts that will be used for      280   Fri Jan 27 14:56:55 2017 Gabriele Optics Daily Progress Optical lever setup completed The four optical levers are completely installed and aligned to a horizontal reference.      287   Wed Feb 1 15:23:42 2017 Gabriele Optics Noise hunting Wandering line is due to the laser The wandering line I mentioned in my previous elog, which is spoiling most of the sensitivity, turns out to be power noise of the laser.       291   Mon Feb 6 11:19:13 2017 Gabriele Optics Daily Progress Laser swap The Thorlabs laser has been misbehaving for the whole weekend. Even after many days being continuosly on, the wandering line      295   Tue Feb 7 16:16:37 2017 Gabriele Optics Daily Progress Lasers The high power lasers I tested so far (the Thorlabs 21mW and the JDSU 1125P) are noisy: they both have wandering lines that from      296   Wed Feb 8 17:01:01 2017 Gabriele Optics Daily Progress Two laser installed, setup aligned Today I swapped out the 8mW laser and installed two 2.5 mW lasers. I rebuilt the input part of the optical levers and      300   Thu Feb 9 09:30:52 2017 Gabriele Optics Daily Progress Two laser installed, setup aligned The lasers are behaving well, there is no high noise or wandering lines. The spectrum below is taken in air: that explains the      301   Thu Feb 9 11:35:27 2017 Gabriele Optics Configuration QPD calibration This morning I measured the beam profiles at the QPD positions. As expected, the beams are not gaussian there, since we are seeing  11x    311   Fri Feb 17 13:44:47 2017 Gabriele Optics Daily Progress Swapped picomotor and re-alignment Since I had recurrent problems with the picomotors used for QPD3, I swapped them with another Newport motorized mirror that      331   Fri Mar 10 16:44:13 2017 Gabriele Optics Daily Progress Updated in vacuum periscope of CR0 This afternoon I removed the old periscope from CR0 and installed a new one with finely adjustable mount, like those in the new chamber.      336   Thu Mar 30 15:23:44 2017 Gabriele Optics General Swapped HeNe laser in CR0 The JDSU HeNe laser 1103P that I was using is dead. I swapped it with a JDSU 1125P borrowed from the 40m.      338   Fri Apr 7 16:19:03 2017 Gabriele Optics Daily Progress New 1103P laser installed This afternoon I installed the new Lumentum (former JDSU) HeNe laser, model 1103P in CR0.      454   Tue Jan 30 09:19:09 2018 Gabriele Optics Configuration Setup for 50mm disks I realigned all optical levers to measure the 50mm disks. In brief, I moved the input 2" mirrors, the in-vacuum 2" mirrors      459   Tue Feb 13 16:28:49 2018 Gabriele Optics Configuration Setup resigned for 75mm disks        479   Thu Mar 8 09:40:10 2018 Gabriele Optics Configuration Realigned all optical levers to horizontal reference        497   Tue Mar 27 16:36:49 2018 Gabriele Optics Configuration Optical levers re-aligned for 50mm substrates        658   Fri Apr 12 09:36:54 2019 Gabriele Optics Configuration Realignment I realigned the entire CR1-4 setup ensured that beam out of the chamber are at 6" height everywhere.      15   Thu May 19 11:36:04 2016 Gabriele Mechanics Design A first design of the disk assembly Here are some screenshots of the disk assembly and a look at how four of them will sit into the vacuum chamber. The Solidworks models      19   Fri May 27 02:09:37 2016 Gabriele Mechanics Characterization Lowest usable mode of fused silica disks I did some FEA simulation of fused silica disks, to identify the lowest usable eigenmode. By usable I mean a mode that has zero elastic      76   Wed Aug 10 10:04:35 2016 Gabriele Mechanics Daily Progress The prototype of the disk retain system is here Yesterday we received the prototype of the disk suspension and retain system. Everything looks good. I checked that the disk fits  6x    124   Fri Sep 23 08:11:48 2016 Gabriele Mechanics Daily Progress Test of the disk retaining ring motion In brief, it doesn't work. The magnets and coils are strong enough to push up the ring with a sample inside, but the friction      189   Tue Nov 15 10:35:11 2016 Gabriele Mechanics Daily Progress Parts for laser polishing setup are here The parts all fit as expected. They're mounted on the stages.      266   Thu Jan 19 14:16:53 2017 Gabriele Mechanics Design New concept for retaining ring motion Since my experiment with coil and magnets didn't work out very well, here's a new concept for the motion of the four  7x    284   Tue Jan 31 11:21:44 2017 Gabriele Mechanics Daily Progress Retaining ring mechanics All parts for the motion of the retaining rings have been received and are ok. We're going to clean and bake them.       303   Fri Feb 10 17:16:28 2017 Gabriele Mechanics Daily Progress Translation stage to move retaining rings This afternoon I installed the picomotor and the translation stage that will be used to move the retaining rings up and down.      304   Sat Feb 11 16:22:26 2017 Gabriele Mechanics Daily Progress Translation stage to move retaining rings The ring motion up and down was not very smooth, again due to friction on the centering pins.      405   Thu Aug 10 13:36:08 2017 Gabriele, Zach Mechanics Configuration ESD moved closer to disk in CR0 We first measured the distance of the ESD from the disk in the test chamber (CR0). We had to remove the retaining ring to have      406   Fri Aug 11 09:22:21 2017 Gabriele Mechanics Configuration ESD moved closer to disk in CR0 The plots below compare the SNR and peak amplitude of all excited modes, in the new and old configuration. The new confgiuration

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