40m
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OMC_Lab
CRIME_Lab
FEA
ENG_Labs
OptContFac
Mariner
WBEEShop
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40m Log |
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Mon Jul 4 10:30:37 2016, ericq, Update, General, Preliminary vent plans
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Tue Jul 5 17:14:02 2016, ericq, Update, General, Vent progress 
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Tue Jul 5 19:10:41 2016, rana, Update, General, Vent progress
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Tue Jul 5 21:51:35 2016, ericq, Update, General, Vent progress
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Tue Jul 5 23:38:42 2016, gautam, Update, General, Vent progress - ETMX SUS Coil driver electronics investigation
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Wed Jul 6 22:58:01 2016, gautam, Update, General, Vent progress - ETMX SUS Coil driver electronics investigation
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Thu Jul 7 00:25:07 2016, ericq, Update, General, Vent progress - ETMX SUS Coil driver electronics investigation
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Thu Jul 7 10:49:03 2016, gautam, Update, General, Vent progress - ETMX SUS Coil driver electronics investigation
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Fri Jul 8 11:35:45 2016, gautam, Update, General, Vent progress - ETMX SUS Coil driver electronics investigation
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Fri Jul 8 11:48:09 2016, Koji, Update, General, Vent progress - ETMX SUS Coil driver electronics investigation
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Fri Jul 8 14:03:26 2016, ericq, Update, General, ETMX removed from suspension
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Fri Jul 8 16:33:26 2016, ericq, Update, General, ETMX removed from suspension
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Fri Jul 8 20:44:09 2016, Koji, Update, General, ETMX removed from suspension 6x
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Sun Jul 10 15:38:01 2016, ericq, Update, General, ETMX in guiderod/standoff gluing fixture 6x
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Tue Jul 12 16:08:00 2016, ericq, Update, General, ETMX ruby guided gluing
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Wed Jul 13 21:13:51 2016, Koji, Update, General, ETMX guide rod gluing / ETMY Magnet gluing 13x
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Thu Jul 14 22:29:57 2016, ericq , Update, General, ETMX guide rod gluing / ETMY Magnet gluing
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Fri Jul 15 16:23:51 2016, ericq , Update, General, Gluing setbacks 
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Tue Jul 19 16:39:29 2016, Lydia, Update, General, ETMX magnet gluing/guiderod excess glue removed 
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Wed Jul 20 13:58:55 2016, Steve, Update, SUS, SUS damping out of vac chamber   
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Thu Jul 21 17:01:59 2016, ericq, Update, General, ETMX magnet gluing/guiderod excess glue removed
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Fri Jul 22 23:03:23 2016, gautam, Update, General, ETMX suspension - progress    
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Sun Jul 24 03:43:56 2016, ericq, Update, General, Magnet positioning
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Mon Jul 25 13:01:49 2016, ericq, Update, General, ETMX suspension - progress    
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Mon Jul 25 13:47:19 2016, rana, Update, General, ETMX suspension - progress
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Mon Jul 25 17:01:54 2016, Steve, Update, SUS, ETMX suspension - progress
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Mon Jul 25 20:37:46 2016, gautam, Update, General, ETMX suspension - Side OSEM test
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Tue Jul 26 18:07:57 2016, gautam, Update, General, ETMX suspension - Further OSEM Tests
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Thu Jul 28 03:22:28 2016, ericq, Update, General, ETMX magnets re-reglued
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Thu Jul 28 13:49:44 2016, gautam, Update, General, ETMX magnets re-reglued 
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Thu Jul 28 17:48:17 2016, gautam, Update, General, ETMY LR magnet broke off
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Thu Jul 28 22:43:03 2016, rana, Update, General, ETMY UL magnet broke off
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Wed Aug 3 10:52:03 2016, Steve, Update, General, ETMY soaking dish  
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Fri Jul 29 03:32:30 2016, ericq, Update, General, ETMX suspended once more
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Fri Jul 29 13:17:34 2016, Koji, Update, General, Oven
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Thu Jul 14 01:00:33 2016, Koji, Update, General, ETMX ruby guided gluing
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Thu Jul 28 16:43:01 2016, Lydia, Update, General, ETMX aluminium standoff groove condition   
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Fri Jul 8 21:22:38 2016, gautam, Update, General, Vent progress - ETMX SUS Coil driver electronics investigation
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Wed Jul 6 09:34:26 2016, Steve, Update, General, PRM sensing voltage LR
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Wed Jul 6 19:36:45 2016, Koji, Update, General, SUS Vmon  
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Thu Jul 7 15:23:39 2016, ericq, Update, General, SUS Vmon
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Thu Jul 7 16:05:55 2016, Koji, Update, General, SUS Vmon
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Thu Jul 7 17:12:50 2016, Johannes, Update, General, Vent progress   
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Tue Jul 12 23:51:16 2016, Johannes, Update, General, Vent progress - ETMY inspection 
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Wed Jul 13 00:38:25 2016, Johannes, Update, General, Vent progress - ETMY attempted repositioning
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Tue Jul 19 13:21:42 2016, Johannes, Update, General, Vent progress - ETMY attempted repositioning
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Sun Jul 10 17:33:00 2016, ericq, Update, General, Vent progress
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Mon Jul 11 15:13:22 2016, gautam, Update, General, Vent progress: in-date First Contact procured
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Message ID: 12335
Entry time: Mon Jul 25 20:37:46 2016
In reply to: 12331
Reply to this: 12340
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Author: |
gautam |
Type: |
Update |
Category: |
General |
Subject: |
ETMX suspension - Side OSEM test |
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[Lydia, gautam]
Summary: We did some preliminary tests to check if at least one of the side magnet positions is usable for the side OSEM. We mainly wanted to check how much dynamic range we lose because of the sub-optimal longitudinal positioning of the side magnet. We found that when the side magnet was mainly moving along the axis of the side OSEM (with minimal yaw motion as gauged by eye), the PD voltage bottomed out at ~80 counts (while the completely unoccluded readout was ~800 counts).
Details:
- First, we placed the face OSEMs into their holders one by one, and adjusted their position till the readout was approximately half the saturation value (as judged by the average value of the readout, at this point, the mirror was still swinging around a fair bit).
- Next, we enabled the POS, PIT and YAW damping (with all existing settings unchanged), but with the SD coil input and output disabled. We had to increase the watchdog threshold to ~600mV.
- Once the optic was reasonably well damped (~70mV on the watchdog was the best we saw), I put in the side OSEM till the PD was completely occluded. At this point, I enganed the earthquake stops, and then released the mirror such that it was freely hanging. I then observed the optic by eye, and noted a time when the dominant motion was along the axis of the side OSEM coil (i.e. minimal YAW motion).
- Attachment #1 shows time series plots of the 5 OSEM PD voltage monitors. Perhaps because the side OSEM input was disabled, the damping wasn't as efficient as it normally is (also there is a fan blowing air around the clean bench). But at the point indicated on the plot, the YAW motion was negligible to the eye, while the dominant motion was along the axis of the coil. During this time, the readout bottomed out at approximately 10% of the saturation value (towards the end of these plots, I disabled the damping loops and began pulling the OSEMs out one by one). Because the damping was imperfect, this is only an approximate guess of how much dynamic range we are losing. But does this warrant regluing the side magnet?
Other remarks:
- The 4 face magents were reasonably well centered in the coil. While Eric and I were looking at this earlier today, the LL magnet looked a little close to the coil, but after putting all 4 OSEMs in, the situation looked reasonable to the eye. I couldn't take pictures because of space constraints, and furthermore, it's almost impossible to hold the camera in the correct vertical position.
- Steve, Eric and I couldn't find the OSEM gender changer anywhere in the lab and it wasn't in the box it was advertised to be in. So we made a custom cheater cable, and cleaned it by wiping with Isoprop., and wrapped it in foil for use in this test. The OSEM pins should probably be cleaned before we put these back in vacuum.
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