Given the request for a lighter maintenance period, the only work I performed on HAM 8 was sealing the remaining SUS bellows for contamination mitigation and mounting the lifting crossbeams. I spent the remainder of the maint period finalizing the machining modifications to the SEI transport tooling (details on this work to come in a future aLog).

Tyler G

Gerardo M. Tyler G. Chris S.

With purge air at a dew point of -47?c~, the team decoupled HAM 8 from the mode cleaner tube. Using drawbars/turnbuckles, the bellows on the mode cleaner tube was compressed just enough to allow for both 60" shipping covers to be craned in place and installed with their respective hardware. C3 covers were then placed outside the hard cover on both the chamber and mode cleaner sides (not unlike the current config of the HAM7/8 joint). After a successful decoupling from the remained of the VE, we broke all footing bolts loose to prepare for future efforts to exercise the chamber from the grout below.

Bubba G, Chris S, Tyler G

A focal point of yesterdays extended maintenance phase was exercising the footing of the HAM 7 chamber. This was performed partially to ensure that future efforts to hoist and move the HAM 7 chamber could proceed without issues related to any adherances between the footing and the grout below. 

Per Bubbas request, I fabricated two crossmembers that span the framework of the HAM chamber. These crossmembers utilize existing holes within the footing and allowed for the use of two single-stage 10 ton Enerpac hydraulic rams to be placed at opposing ends of the chamber for lifting. With all 24 anchor bolts loosened and raised approximately .5"- 1". Pressure was applied to the jacks and subsequently the crossmembers. With minimal effort, the chamber was successfully lifted and freed from its grout footing.

As requested by Chandra, All 4 of the seismic bellows were adequately covered with ameristat and taped to ensure that no disturbed particulate might contaminate these areas during the work. Additionally, the near side bellows of HAM 8 were also sealed off.

Bubba, Chris, Tyler


The remaining doors on HAM 11 and 12 (north and south) have been removed. We have put C3 covers in their place while we await shipping covers. Additionally, the thru holes in septum that separates the two volumes is now capped using the 3 blanks Gerardo located for us. All HAM 11/12 doors are now hanging on the door caddy near the large equipment access roll-up door.

I just turned off the HVAC in the north end of the H-2 electronics room and closed the door. I will monitor the south room for temperature change throughout the day.

The cooling system for the H-2 electronic building was repaired yesterday, (see FRS 4271), and is functioning correctly.

The cooling system failure at the H-2 electronics building (FRS 4271) was due to a defective flex joint in the line set from a outdoor unit compressor to the building. The flex joint has been replaced and the line set and compressor are being drawn down. There will be a small vacuum pump running near the outdoor units throughout the night. If there are no more leaks, the unit will be recharged with gas and back running tomorrow. The vacuum pump will run unattended, however, if there are any issues with the running of the pump, please do not hesitate to call me. 
The commissioners have been apprised of this also.   

Prep work continued yesterday in the West Bay. Signage was generated and attached to pallets and storage boxes, including the BS/FM at the end of the shelving units. BS/FM container ratchet was sealed. I found that the ICS paperwork for many parts could not be completed because of shipments not being received so I worked on that for a while this morning. I also participated in a telecon with the PSL folks WRT storage issues. We made some progress in giving the PSL crates at Y Mid unique identifiers and correlating existing info (Benno's sketch and spreadsheet, RS and MR inspection info) with the new identifiers. Please see attached documents for further details. I applied a few signs in the LVEA. I will continue to work ICS issues this afternoon.

I sealed up the two new HXTS that were placed in the meat locker yesterday. I also attached signage/drawings/ICS records to the five HXTS in the meat locker. I inventoried and separated MC Baffle parts this morning: small parts were placed in a tote and large parts were wrapped/attached to their shelf with plastic wrap and a few lengths of blue tamper-evident tape. I worked on AC and Elliptical Baffle parts this afternoon: there are two plastic wrapped and taped pallets on the floor level of Shelving Unit B in the West Bay containing these parts. I also applied signage to a HAM Shipping, HAM Storage, and BSC Storage Container for show-and-tell purposes.

Late yesterday I had a conversation about PCal crates with Rick: he is planning on sorting things with me Thursday-Friday of this week.

The "shortie" OpLev piers were moved to the VEA of X Mid. I spent a majority of the day working on documenting (drawings, ICS updates), marking and sealing these crates. Specific details below. I worked documentation and marking on the two Giraffes already at X Mid and started documentation of the leaners and the periscope.

Shortie OpLev Piers and Base Plates
3 x D1000452 + 3 x D1000434
2 x D1001301 + 4 x D1000434
3 x D1001854 + 3 x D1000434

In addition, I started to work documentation for baffles.

The Apollo crew and I spent much of the day trying to understand the exact contents of crates at Y Mid so that we can sequester 3IFO-destined items as required by NSF. We made some progress. Four unmarked crates contained PCal Pier Weldments (aka Pylons). The crates were marked and drawings attached. Serials numbers 1 (destined for X End) and 2 (destined for Y End) are stored in the middle bay. Serial numbers 4 and 5 are destined for 3IFO and are therefore stored in the VEA: hard copies of the ICS Part Records showing updated location and sub-location were added to the drawings. (For the sake of the curious: serial number 3 is in the LSB lab.) We are still trying to get a handle on exactly how many of remaining crates in the VEA are 3IFO PSL-related. I sent an email (with pix) to Benno trying to get some clarification of his lists.

In addition, the first article OpLev test set-up removal and clean-up were completed. The leaner and the base plate were removed from the VEA: they will remain by the outer roll-up door until I understand whether that particular item is destined for here or 3IFO.

The NSF Storage Review will occur here on 09 April 2013. Prep work is going ahead on several fronts: LVEA-West Bay, Y Mid, and X Mid.

-In the West Bay, one section of the western-most pallet rack has been cleared of everything but 3IFO-related items. Items in this rack are currently labelled either for India or 3IFO. (2 pix below) As soon as possible, we will install a gate on this section to create a controlled inventory area. Three Triple Suspensions are stored in the Meat Locker (barrels ratchet strapped to pallets, ratchet handles zip-tied with tamper-evident serial numbered tags). (2 pix below)

-At Y Mid, a series of activities is in progress. TCS Optical Tables were stacked and rotated to create a forklift path through the outer receiving bay. This path will be continue through the middle bay to the VEA. A crane set-down/forklift turn-around area will be marked out in the yellow and black hazard tape: please DO NOT store anything in this stay-clear area. Sixteen(4 chambers-worth) iLIGO external SEI isolation units have been stored in the middle bay and VEA: they are being migrated out to the LVEA where they will be stored until they are installed on H2 HAMs. The OpLev first article test set-up is being removed and the grout pads cleared. Several 3IFO PSL crates have been identified and will be sealed ASAP: several additional PSL-related crates need to be identified. One PSL Chiller crate has been sealed with tamper-evident tape for testing purposes. Two TMS Upper Structure crates have been identified and labeled. One TMS US crate has been sealed with silver serial-numbered tamper-evident tags for testing purposes. Three unidentified crates are in the middle bay along with an electrical rack. The electrical rack needs to be de-populated and Richard will take care of that when convenient. The tentative long-term storage plan calls for all 3IFO storage at Y Mid to be in the VEA and the VEA locks will be changed to provide controlled access.

-At X Mid, a few activities will be under way this week. A forklift path will be cleared from the outer roll-up door through the middle bay to the VEA. A crane set-down/forklift turn-around area will be marked out between the inner roll-up door and the beamtube. The forlift path and the crane set-down area will be marked out in the yellow and black hazard tape: please DO NOT store anything in these stay-clear area. OpLev piers (some coming from other out buildings)will be concentrated to the VEA. Giraffe crates (already in place) and shortie crates will be sealed. The tentative long-term storage plan calls for 3IFO storage to occupy most of X Mid and outer man-door locks will be changed to provide controlled access.

The Apollo crew and I will continue to work on 3IFO LTS issues through 08 April as the opportunity arises.

Re-energized the following devices at the Y end station which were turned off on Friday, Oct. 5, 2012 for software debugging:

H2-SEI-C1 rack - (3) coil drivers, reset overtemp condition after powerup.
H2-TCS-C1 rack - Ring heater driver, A/I filter box.
H2-SUS-C1 rack - (3) A/I filter boxes.

I have generated Fscans for many of the SUS, ISI, and PEM channels
listed here,

https://wiki.ligo.org/foswiki/bin/view/DetChar/OneArmTestLineInvestigations

Especially over the weekend I finished generating Fscans during
significant lock stretches ending on August 22, 25, 28, and 31.

You can find the SUS, ISI,and PEM Fscans respectively here:

https://ldas-jobs.ligo-wa.caltech.edu/~pulsar/fscan/H2_OneArm/H2_OneArm_SUS/fscanNavigation.html

https://ldas-jobs.ligo-wa.caltech.edu/~pulsar/fscan/H2_OneArm/H2_OneArm_ISI/fscanNavigation.html

https://ldas-jobs.ligo-wa.caltech.edu/~pulsar/fscan/H2_OneArm/H2_OneArm_PEM/fscanNavigation.html

Click on a date and then the channel name to get the Fscan plots and links to
the data files.

Note that the PEM Fscans also include the length sensing channel, e.g.,
H2:ALS-Y_ARM_LONG_IN1_DQ.

For those that mine the Fscan data, from the cluster at LHO look for the
data files respectively under,

/home/pulsar/public_html/fscan/H2_OneArm/H2_OneArm_SUS

/home/pulsar/public_html/fscan/H2_OneArm/H2_OneArm_ISI

/home/pulsar/public_html/fscan/H2_OneArm/H2_OneArm_PEM

Finally, the Fscan plots do not appear for some SUS channels, because
they were all zeros. Specifically, for Aug. 31, I find these channels
were all zeros:

H2:SUS-ETMY_L1_MASTER_OUT_LL_DQ
H2:SUS-ETMY_L1_MASTER_OUT_LR_DQ
H2:SUS-ETMY_L1_MASTER_OUT_UL_DQ
H2:SUS-ETMY_L1_MASTER_OUT_UR_DQ
H2:SUS-ETMY_L2_MASTER_OUT_LL_DQ
H2:SUS-ETMY_L2_MASTER_OUT_LR_DQ
H2:SUS-ETMY_L2_MASTER_OUT_UL_DQ
H2:SUS-ETMY_L2_MASTER_OUT_UR_DQ
H2:SUS-ETMY_L3_MASTER_OUT_LL_DQ
H2:SUS-ETMY_L3_MASTER_OUT_LR_DQ
H2:SUS-ETMY_L3_MASTER_OUT_UL_DQ
H2:SUS-ETMY_L3_MASTER_OUT_UR_DQ
H2:SUS-ITMY_L1_MASTER_OUT_LL_DQ
H2:SUS-ITMY_L1_MASTER_OUT_LR_DQ
H2:SUS-ITMY_L1_MASTER_OUT_UL_DQ
H2:SUS-ITMY_L1_MASTER_OUT_UR_DQ
H2:SUS-ITMY_L2_MASTER_OUT_LL_DQ
H2:SUS-ITMY_L2_MASTER_OUT_LR_DQ
H2:SUS-ITMY_L2_MASTER_OUT_UL_DQ
H2:SUS-ITMY_L2_MASTER_OUT_UR_DQ
H2:SUS-ITMY_L3_MASTER_OUT_LL_DQ
H2:SUS-ITMY_L3_MASTER_OUT_LR_DQ
H2:SUS-ITMY_L3_MASTER_OUT_UL_DQ
H2:SUS-ITMY_L3_MASTER_OUT_UR_DQ
 

During a cavity scan, a second modulation is applied to the laser frequency. The response of a Fabry-Perot cavity to laser frequency modulation contains information about the cavity parameters, including cavity length, free spectral range, modal spacing, and the radius of curvature of the cavity optics. The goal of cavity scans is to measure cavity characteristics and characterize their time evolution in response to heating of the optics.

While the 532 nm ALS laser is locked to the arm cavity, laser frequency modulations are injected into the Innolight Prometheus frequency-doubled laser through the laser frequency servo (Common Mode A) with an SR785 signal analyzer. These frequency modulations are transmitted into the 1064 nm beam used for PSL phase locking and the 532 nm beam used for arm cavity locking. The PSL phase locking beam does not interact with the arm cavity, and the signal from the RF photodiode is used as a proxy for the signal injected into the arm cavity. The arm cavity reflection photodiode gives the output signal, which the SR785 divides by the input signal to produce a transfer function.

Automation of SR785 measurements is necessary to perform and store transfer functions in quick succession over a period of hours. A Prologix GPIB-Ethernet controller is used for remote control and retrieval of data from the SR785. Scripts for performing transfer functions and retrieving data using the GPIB-Ethernet interface were created for use at the 40m interferometer, and were used for cavity scan transfer functions here. The Python script exttt{TFSR785.py} performs a single transfer function.

A bash script, exttt{autoTF}, was used to repeatedly call this Python script. This script was originally set to perform one scan from 30kHz to 80kHz, alternate smaller scans around the first-order modes (from 46-47 kHz and from 65.75-66.75 kHz) three times, then repeat until 12 hours elapses or the script is terminated. During the scan, it was found that the first-order peaks moved further than anticipated, so the script was altered to scan from 45-46 kHz and 66.75-67.75 kHz. In future scans, the smaller scans will be run from 45-47 kHz and 65.75-67.75 kHz for the duration. For all scans, the amplitude of the excitation was 10 mV, and 10 averages were used.

The ALS laser output power is 100 mW, and the SR785 excitation output current is 100 mA. Therefore, the modulation depth for these cavity scans is 0.1, or 1% of power in the modulation sidebands.

The attachment cavity_characterization.pdf contains a more thorough explanation of the motivation behind cavity scans, and some preliminary results. The attachment cavityshift.pdf plots a cold cavity scan and a cavity scan after 2.5 hours of heating on the same axes, showing the shift in modal spacing with ITM heating.

Below is information I sent to Det. Char. and DASWG last week.

Generation of H2 OAT Locked Segments is now running as a cron job on ldas-pcdev1 at LHO. It runs once per day.

The segments exist from Jul 19 2012 07:59:44 PDT. (Note that LDAS has been archiving all raw H2 data since Jul 06 2012 19:00:00 UTC.)

The segments are updated via cron one per day such that segments up to ~8 am Pacific time of the current day should appear by ~10:30 am of the same day.

The segments are going into the https://segdb2.ligo.caltech.edu database, and are called

 H2:DCH-ONE_ARM_TEST_LOCKED:1

To retrieve the segments from the database, from the LSC clusters run for example, 

$ export S6_SEGMENT_SERVER=https://segdb2.ligo.caltech.edu

$ ligolw_segment_query --database --query-segments --include-segments
H2:DCH-ONE_ARM_TEST_LOCKED:1 --gps-start-time 1029674400 --gps-end-time
1029682800 | ligolw_print -t segment:table -c start_time -c end_time -d " "

Thi example returns,

1029674400 1029678900
1029679800 1029680340
1029680400 1029681180
1029681300 1029681360
1029681420 1029681480
1029682740 1029682800

The segments are also output in ASCII, and available in segwizard format here,

http://ldas.ligo-wa.caltech.edu/ldas_outgoing/FindLockedSegs/H2OneArmSegs/segWizFiles/

and in plain startTime endTime format here,

http://ldas.ligo-wa.caltech.edu/ldas_outgoing/FindLockedSegs/H2OneArmSegs/segFiles/

For experts:

The segments are generated by running, for example,

$ find_locked_segments.py -i H2 -t H2_M --min-lock-duration=1 -c h2_onearm_locked.ini --seginsert-inifile h2_onearm_seginsert.ini --lasttimes-file h2_onearm_lasttimes.txt
-bash-4.1$ cat h2_onearm_locked.ini 

where h2_onearm_locked.ini contains this one line,

 ALS-Y_REFL_B_PWR_OUT16.mean 4300 10000

which means, the criteria for lock is that H2:ALS-Y_REFL_B_PWR_OUT16.mean is between 4300 and 10000.

The script, find_locked_segments.py, is in Det Char CVS here:

CVS/Root = :pserver:anonymous@gravity.phys.uwm.edu:/usr/local/cvs/ligovirgo

CVS/Repository = detchar/code/psl

I've set up a cavity scan to run as often as the GPIB-Ethernet/SR785 system allows (~ every 165 s), in preparation for observing shifts after the ring heater is turned on later today. Excitation B of Common Mode A will be left on for the duration of these measurements.

Elli and I took transfer functions of the OLTF using common mode B. The optimal gain setting was found to be -14. This results in a UGF of approximately 10.4 kHz while keeping the resonance at 42 kHz below 0 dB (maximum about -2 dB).

At higher gains (-10, -12, -13), the 42 kHz peak was consistently greater than 0 dB.