Displaying reports 79281-79300 of 82999.Go to page Start 3961 3962 3963 3964 3965 3966 3967 3968 3969 End
Reports until 20:19, Saturday 11 August 2012
H2 AOS
alberto.stochino@LIGO.ORG - posted 20:19, Saturday 11 August 2012 (3825)
Arm cavity briefly locked
I locked the arm cavity for about half an hour but the lock broke when I enabled the isolation on ITMY ISI and the HEPI and ISI watchdogs tripped. 
After that I couldn't' restore the watchdogs anymore. 
The arm is currently unlocked.
H2 ISC
alberto.stochino@LIGO.ORG - posted 20:19, Saturday 11 August 2012 (3824)
ALS reference cavity and PLL locked again
The ALS reference cavity was in an unstable mode and the PLL could not get locked.
I re-locked the refcav with these settings:

Coarse 384
Fine 206
Common 300
Fast 638
Offset 194

The fiber output has dropped from ~300 uW to 80 uW since Bram installed a Faraday at the output of the reference cavity. As a consequence the beat note amplitude is about -25 dBm (-35 dBm at the monitor spigot of the phase/freq discriminator board). I had to increase the laser power otherwise the amplitude would have been even smaller.

The PLL is now locked again, with the laser at the end station set to 42.27 degrees.

Locking the PLL was tricky. One of the switches in the CMB_A MEDM screen was actually stuck in an open state, although it appeared to be closed on the screen. the switch was malfunction and it had a state value of 65536 instead of 1 or 0. I forced it to be 1 by EZCAWRITE.

Also there CMB_A board Input1 gain is now limited to -16 or less, vs -6 as it used to be, because the PLL becomes unstable at -15 and up. This is strange since the loop gain phase is flat up to 80 kHz and the phase margin is large (~60 degrees up to 80 kHz; the UGF is 10 kHz). I suspect something might be wrong with the slow control interface of CMB_A.
H2 ISC
bram.slagmolen@LIGO.ORG - posted 21:20, Friday 10 August 2012 (3822)
OAT locking - not locked

I reset all the watch dogs on the ITM HPI and ISI. ITM ISI is in damping state. Didn't press the isolate stage command.

I try to lock the arm (remotely), but it seems that H2:ALS-Y_FIBR_SERVO_FASTMON (e.g. the CMB-A fast output, which is the fiber locking feedback signal to the laser PZT) is railed at -10V. The beatnote frequency readout is at 60 MHz, but not sure if that is real or not. Should go out to EY to make sure all is well. (PS. to engage the fiber locking open the 'Laser' screen and press 'on' at the lower left).

I turned off the FIBR servo (CMB-A), to make sure the temperature doesn't walk away.

The OAT RefCav monitor signal seems to be ok (~0.1 mW).

H1 TCS
aidan.brooks@LIGO.ORG - posted 20:17, Friday 10 August 2012 (3821)
ETMY ring heater is OFF

Turned off ETMy ring heater

H1 IOO
deepakmanoj.nandakumar@LIGO.ORG - posted 18:16, Friday 10 August 2012 (3820)
Faraday Isolator - Prep Work

[David T, Cheryl V and Deepak K]

H1 IOO
deepakmanoj.nandakumar@LIGO.ORG - posted 18:04, Friday 10 August 2012 (3819)
HAM3 IO Optics - Prep Work

[David T, Cheryl V and Deepak K]

H2 CDS
david.barker@LIGO.ORG - posted 17:49, Friday 10 August 2012 (3818)
inelegant fix to EPICS slow down when backing up h1boot and h2boot

The backup of h1boot and h2boot still slows the EPICS associated with the front end systems. Even though I only backup at 5am daily, the slow down is still evident at that time. Until the root cause of this problem can be resolved, Jim and I came up with a totally inelegant solution of slowing down the data rate of the network switch ports which connect h1boot and h2boot to the backup machine. These ports were demoted from 1GB to 100MB. We tested both h1boot and h2boot backups. They take about an hour each (compared with 20mins previously). The disk I/O rate keeps below 5MB per 5 second average. The EPICS problems were previously observed to occur when the disk I/O exceeds 8MB per 5 second average.

A large percentage of the backups concern the awgtpman log files which can be many 100MB each. We will work next Tues on installing new awgtpman code to reduce the logging content of these files.

H1 ISC
aidan.brooks@LIGO.ORG - posted 17:48, Friday 10 August 2012 (3817)
Arm cavity not locked

The arm cavity is unlocked right now due to issues with the HEPI on ITMY.

H1 AOS
david.barker@LIGO.ORG - posted 17:42, Friday 10 August 2012 (3815)
IOP Sus Watchdog installed on HAM 2 and 3

I have installed the IOP SUS watchdog system for the H1 HAM2,3 systems. The sus systems are h1sush2a and h1sush34, the seismic system is h1seih23. Following the LLO system, the suspension systems being monitored are

HAM2: PR3

HAM3: PR2 and MC2

If any of these sus system trip, the DACs on h1seih23 (HEPI and ISI in HAMS 2,3) are tripped via the Dolphin IPC.

Currently SEI HAM2,3 is permanently tripped due to missing PR3 OSEMS. I will reconfigure the system into a working state when the ISI are unlocked in HAM2/3.

The H1 IOP watchdog MEDM is available from the H1 SITEMAP

H1 TCS
aidan.brooks@LIGO.ORG - posted 16:56, Friday 10 August 2012 (3814)
ETM Y ring heater is ON

I turned on the ETMY ring heater around 23:47 UTC, requesting 630mA in each segment. I'm going to leave it running overnight and into the weekend to get a good measurement of the thermal time constants.

H1 SUS
betsy.weaver@LIGO.ORG - posted 16:38, Friday 10 August 2012 - last comment - 17:49, Friday 10 August 2012(3813)
PR2-04 suffers broken magnet in suspension, chamber-side

After finishing assessing and adjusting the roll and pitch of the suspensed PR2 optic, we started adjusting the 14 OSEM positions.  During the coarse of this, we broke a magnet off of the PR2 optic.  Mark Barton and Travis are looking into regluing it onto the optic within the suspension, in an effort to retain some sort of schedule for next week while our team is stretched over to LLO.  Lesson learned is that the EQ stops need to be set very close while adjustments are being made.  I thought this was the case when we were working on it, but clearly not close enough.  It's unfortunate that the top BOSEM adjustment tools and your hand are very close to the suspension wire making knocking the suspended masses around easy.

Comments related to this report
mark.barton@LIGO.ORG - 17:49, Friday 10 August 2012 (3816)
Mark Barton and Travis Sadecki

We did a repair as follows:

1. We set up a jig using parts from the AOSEM tester, including two translation stages, some posts, and a holder intended for a 10x10 magnet (see attached photo).

2. We cleaned up the magnet-standoff assembly and adhered it magnetically to the steel disk of the magnet holder.

3. We aligned the new standoff with the glue ring on the optic from the original standoff using the translation stages.

4. We backed off the standoff and removed the glue ring with a razor blade and an acetone swab.

5. We applied glue to the standoff and brought it in to touch the optic. 

The glue will be left to set over the weekend and then the magnet holder should be able to be backed away - the magnetic attraction is not very strong.

Images attached to this comment
H1 SEI
hugh.radkins@LIGO.ORG - posted 16:37, Friday 10 August 2012 (3812)
WHAM3 Optical Table Payload Secure
Mitchell, Jim & Hugh
The first layer of the additional payload mass (D0901075) on the West side of HAM (90kg) has been bolted down to the table; we did this Thursday.  There is still 210kg to go.
H1 SEI
hugh.radkins@LIGO.ORG - posted 16:31, Friday 10 August 2012 (3811)
WHAM5 ISI Installation Readiness
Remain to Do:
At ISI: Complete Cable SN Inventory, Replace Act Windows, Confirm Cable security for flight.

At HAM5: Loosen Door Bolts, Clean around Doors, Remove Doors, Remove Top Conflat, Remove Legs from A-Frames, Position A-Frames at Chamber, Install I-Beams, Position I-Beams per Procedure, Position Cart under Beams, Fly ISI, etc...

Thanks to Christina, Karen, Cris, MarkD, ScottL, DevilEd, Jim, Mitchell, Greg, & Eric
LHO VE
kyle.ryan@LIGO.ORG - posted 16:11, Friday 10 August 2012 (3810)
Vented Vertex Volume
Prior to venting, I sprayed helium around the welds which join the thin-wall MC tube to the thick flanges.  The LD background was 3.5 x 10-9 torr*L/sec -> no responses.  I did not spray all of the welds on the MC nozzles, roll seams or roll butt joints, however.  

Also, PT120A wasn't working today.  I think that I had drug my fall protection tether across the gauge pair the other day during leak testing and must have interrupted the cable connection.  I eventually had to remove and re-installed its cable to get it going which fixed it.  
LHO General
patrick.thomas@LIGO.ORG - posted 15:57, Friday 10 August 2012 (3808)
ops afternoon summary
Cheryl moving TCS lasers into HAM 6 bay
Kyle soft closed GV-5, venting vertex for ISI install into HAM5
X1 SEI
james.batch@LIGO.ORG - posted 15:28, Friday 10 August 2012 (3809)
Restarted models on SEI test stand
Restarted models on the sei test stand (stormy), cpu for the iop was pegged.
H2 AOS
thomas.vo@LIGO.ORG - posted 11:37, Friday 10 August 2012 (3807)
H2 ITMY/ETMY Optical Levers Re-Alignment
The H2 ITMY and ETMY have been re-centered with the cavity beam locked at approximately 10:05 for ITMY and 10:55 for ETMY.  The cavity was locked at the time.

One particular note, all of the electronics for the ETMY optical levers (laser, whitening chassis, power supply) were running off a power strip that was disconnected sometime in the past few days and this caused a loss in signal.  Please don't do this.
LHO General
corey.gray@LIGO.ORG - posted 11:36, Friday 10 August 2012 (3799)
Morning Ops Summary

Morning (8-noon) Notes

OAT Work:  Aiden & crew had the reins for Ring Heater work

Craning activity:  HAM5 ISI had it's Container top removed and the ISI is staged in a cleanroom

H2 ITM/BS CPU Meter went to a MINOR alarm state (value = 13) at 8:27am

Thomas centering oplevs for ITMy & ETMy

Mark Dodson making measurements around BSC8 10-10:15

Kyle is inquiring about venting section of HAM5.

Patrick is covering the afternoon.

H1 TCS
aidan.brooks@LIGO.ORG - posted 11:35, Friday 10 August 2012 - last comment - 11:35, Friday 10 August 2012(3787)
Ring heater and HWS measurements

I turned on the Ring Heater this morning to a nominal 30W of electrical power. We've yet to fully determine the ratio of the radiated power to electrical power, but the most recent number is approximately 2.5W radiated power per 6W electrical power.

I measured the spherical power of the HWS beam -  probing the ETM thermal lens and surface deformation and compared it to the results from a simple COMSOL model of the predicted thermal lens + surface deformation [no fitting]. The results are shown in the attached plot. Bear in mind that the scale of the predicted model will be affected by the delivered power (dependent on the radiated to electrical power ratio) and that the HWS is still operating on a nominal calibration for the optical system - rather than a measured calibration. 

The results are quite similar but there are obvious differences in the time constant. At the moment I would put that down to the simplicity of the COMSOL model - it doesn't include the flats on the sides of the ETM, or the reaction mass or the time constant associated with the ring heater itself.

However, this is the first real aLIGO measurement of thermal lensing with the HWS.

Caution: this is not solely the surface curvature of the ETM - the optical path distortion from the thermal lens is roughly 10x larger than that of the surface curvature.

10-Aug-2012 11:34AM - replaced plot. I had added the incorrect sign to the surface deformation in the model. I've fixed this.

Non-image files attached to this report
Comments related to this report
aidan.brooks@LIGO.ORG - 11:32, Friday 10 August 2012 (3806)

Extra information: 

Ring Heater on at 1028555836

 

Requested current: H2:TCS-ETMY_RING_HTR_SEG1_DC_I_SET_OUTPUT

 

Measured current: H2:TCS-ETMY_RING_HTR_SEG1_I_MON_OUTPUT

Measured voltage: H2:TCS-ETMY_RING_HTR_SEG1_V_MON_OUTPUT

 

Ring Heater Settings
  Requested current Measured current Measured V across RH Electrical power (V*I)
Upper RH segment  630mA  623.4mA  21.485V  13.394W
Lower RH segment  630mA  623.0mA  21.458V  13.368W


HWS Channels:

Defocus @ HWS: H2:TCS-ETMY_HWS_POLYFIT_SPHERICAL_POWER [m^-1]

Defocus @ ETM: (1/mag^2)*H2:TCS-ETMY_HWS_POLYFIT_SPHERICAL_POWER [m^-1]

Displaying reports 79281-79300 of 82999.Go to page Start 3961 3962 3963 3964 3965 3966 3967 3968 3969 End