Weekly Report for Week Ending October 4, 2007

LSC	Administration	Hanford Observatory	Livingston Observatory
Optical & Mechanical	Controls and Data Systems	40 Meter Facility	TNI
LASTI	CIT Science Group	Laboratory Computing	Adv. LIGO Development

Past Weekly Reports

---

LSC Issues (Reitze)

• Most of the MOUs are now complete, with a few LSC groups still outstanding. PIs have been sent reminders.
• The Election and Membership Committee is putting together the October LSC authorlist as mandated by the new publication policy.  In additions, elections for several LSC search group chairs are getting underway.
• The S4 CW PowerFlux/Hough/Stackslide all-sky search has been accepted by Phys. Rev. D with no changes requested by the referees.  Kudos to the PSH team and reviewers for this.
• The SGR 1806-20 QPO search analysis is now published online in Phys. Rev. D at http://link.aps.org/abstract/PRD/v76/e062003

LIGO Laboratory Administration (Lindquist)

STATUS OF LSC MOUs (Lloyd)

• Goddard and Southeastern Louisiana University (shown in table below) were approved and signed off this reporting period. These will be posted and submitted to the DCC.
• The University of Maryland was approved this reporting period, and is now being routed for signatures.
• The University of Texas at Austin has been re-submitted with changes required by the review panel. It has now been posted for review by the panel only.
  
• The table below shows all of the MOUs and their attachments that have been approved and signed off to date, by both the LSC Spokesperson and the LIGO Laboratory Director.

LIGO Hanford Observatory (LHO) and Interferometer Operations (Raab)

Summary of S5 Activities at LIGO Hanford Observatory (compiled by K. Kawabe)

On Sunday, 30 September 2007 at 17:00 local time, S5 data taking officially ended. Following this, post-S5 measurement period started where many tasks for calibration etc. are performed. Operators cover from 8AM to midnight, so the Hanford IFOs are not manned from midnight to 8AM. They are left in Science mode during the night when possible.

The duty cycle of H1 and H2 (from Thu. 27 Sep 2007 to the end of the data taking, Sun. 30 Sep 2007) were 85.0 and 77.3 percent, with typical binary range of 14 to 16 Mpc and 6 to 7+ Mpc, respectively.

Summaries: Range and Duty Cycle update. Tuesday maintenance summary.

Highlights from the LHO elog:

• Earthquakes: A series of big ones from Loyalty Islands, a "big one" (location not found in the elog), Marianas 6.9, and Auckland Islands, N.Z., 7.3.
• Hardware injections were deactivated.
• H1 ISS glitch continued.
• Replacement of CDS NAT router.

Post-S5 activities:

For the latest schedule, see this wiki entry.

• Normal calibration run, which continued for two days.
• Mode cleaner pole frequency measurement using ISS. This technique was found to produce beautiful data.
• Thermal absorption measurement for both H1 and H2
• Alternative calibration techniques tested.
• PEM injection test started on Wednesday. Expect this to continue throughout the week.

Outreach (D.Ingram):

The Math Science Partnership (MSP) in which LHO participates includes four 3-hour school year workshops for ~20 teachers who participated in the 2007 two-week summer course in science inquiry. The first of the four workshops occurred on the evening of 9/27 at ESD 123 in Pasco. Workshop leaders were Peggy Main and Abner Garza from ESD 123, Judy Morrison from WSU-TC, Todd Rogers from Columbia Basin College, and Raab and Ingram from LHO.

LIGO Livingston Observatory (LLO) and Interferometer Operations (Giaime)

No report.

LIGO computing and network security (Roddy)

Reported under General Computing, see below

General computing and LDAS admin (Giardina)

Reported under General Computing, see below

Reported under LDAS System Administration, see below

Data analysis & computing (Yakushin)

Storage/Condor/LDAS admin:

Reported under LDAS System Administration, see below

Data analysis:

Reported under Data Analysis activities, see below

Mechanical and Optical Systems (Coyne)

See Advanced LIGO

Controls and Data Systems (Bork)

See Advanced LIGO

40-Meter Interferometer (Weinstein)

• Tobin fixed the PSL intensity servo cables, including those going into the DAQ, and got the servo working again after Rana's mods. He took a transfer function from PD sensor to CS drive, and now he's working on a calibrated RIN measurement. He also re-enabled the ISS loopswitch in the "mcup" script.
• Pinkesh installed a new compute server named Mafalda.ligo.caltech.edu, and set it up with matlab and various ligo tools.
• Justin has upgraded the installation of mDV at the 40m to the latest version.
• Justin is trying to measure the mode cleaner transmission. He measured the power of the beam into the vacuum at the PSL table, and the power at the MC transmission pickoff port. But we don't know the reflectance of the MC transmission pick off. We're trying to figure it out from what we know about the pickoff mirror in the vacuum chamber.
• Rob has been working on locking the full dual-recycled FP Michelson configuration. The DRMI locks easily, and the hand-off to double-demod RF signals works fine, as do the fast triggers. Adding the arms has been causing lock loss. Tobin fixed the ISS, and that seemed to help. Rob is debugging locking scripts.
• Rana is working on a Bench model for a reconfiguration of the 40m for prototyping the new AdLIGO control scheme. He is considering the use of lighter ITMs to make the optical spring frequency higher and potentially visible in the noise curve. He's also considering whether we will need fixed or suspended folding mirrors in a long PRC.
• Bob and Luke had some challenges while assembling the AdLIGO Faraday isolator from Florida, which has some very strong magnets. They are improving the assembly and safety procedures.

---

Thermal Noise Interferometer (Black)

• We have hit the first snag in recommissioning since the move. The mode cleaner servo is exhibiting a large oscillation around 28kHz, preventing stable operation. This is close to the right frequency to be a mirror mechanical mode, but it drifts around in exactly the way mechanical modes don't. It is also apparently independent of the servo gain.

---

LASTI (Mittleman)

BSC ISI

• While in the process of shaking down the sensors we discovered that one of the actuators was not properly installed. We have had to disassemble one set of actuators and we are now trying to figure out what the problem is.

Quadruple Pendulum

• Ian, Joe(RAL), Stuart(Birmingham), Betsy (LHO), Danny and Janeen(LLO) and Brett(MIT) have been working this week on finishing the quad installation. Brett made an ilog entry on manday describing their progess up to that point.  (http://emvogil-3.mit.edu/ilog/pub/ilog.cgi  10/1/07). Since then they have suspended both chains and are working to balance the masses.

CIT Science Group (Weinstein)

________________

Igor Yakushin:

• Rerunning the first year of S5 analysis with the new version of the coherent waveburst and the latest category 1 and 2 DQ flags.

________________

Kent Blackburn for the GRID Development Group:

GRID APPLICATION DEVELOPMENT ACTIVITIES

•  Wrote agenda for weekly LIGO-Pegasus telecon and attend weekly.
•  LIGO-Pegasus, DASWG and OSG-USERS telecon.
•  Opened GOC ticket FIU_PG associated with problems running the LIGO binary inspiral workflow.
• Studying SQUID documentation in preparation for working on ways to establish communications between Einstein at Home jobs running behind firewalls with the main Einstein at Home server on the internet.
• Studying D-Grid's method for running Einsten at Home. Also studying BOINC and other E@H material.
• Learn how to run extensible VO-centric site testing kit which was released last week by the OSG Users Group.
• Attended OSG-OPS telecon and gave a brief summary of LIGO activity on OSG.
• Prepared and sent out ppt presentation to Thomas Radke and Robert Engel (D-Grid) on Using Pegasus to submit LIGO workflows.
• Troubleshooting tmpltbank job fail at CIT_CMS_T2 and UCSDT2.
• Continue running LIGO test workflow on OSG

OPEN SCIENCE GRID INTEGRATION AND VALIDATION TESTBED

• Attended PEGASUS, DASWG, OSG ITB, and OSG VTB telecon.
• Worked with Abhishek to prepare a list of recent VO engagement on OSG ITB site testings.
• Reinstalled VDT 1.8.1 on osg-vtb, to verify whether OSG-RSV can  run properly.
• Found the osg-rsv start running, but logs into different directory  than expected which cause write permissions errors, send bug list and log files to OSG RSV developers.
• Communnicate with OSG RSV developers Arvind and Scot, eventually narrow down the bug. Bug Fix will release in VDT 1.8.1a. Now temporary manually fix the $VDT_LOCATION/gratia/probe/metric/ProbeConfig lines regarding logging directories.
• Answered questions about dCache installation from user of FNAL.
• Installed OSG 0.7.1 on osg-itb.
• Read OSG squid installation document.
• Ran LIGO work flow on osg-itb against new OSG 0.7.1 release, job finish successfully.
• Installed squid on osg-vtb server, send comments about squid installation to ITB list.
• Validated squid server is working.
• Sent error messages from VO "engage" to site admins (UCSD, BNL, CIT_ITB_1) for attention.

OPEN SCIENCE GRID MANAGEMENT

• Reviewed three statements of work from UIUC, Clemson and Caltech at the OSG Resource Managers' weekly teleconference. These were signed off on by the resource managers. Each was then reviewed by the OSG Executive Director and Facilities Director and signed with only minor edits. One of these edits was to add to the job description for Kent Blackburn a phrase stating "interface with LIGO" in addition to the previous years phrase of perform duties of the OSG Resources co-Manager. This was presented to the Computer Committee for discussion and decided that this was acceptable by all.
• Will be reviewing an additional five Statements of Work this later today.
• Held a special resources managers' telecon early this week to discuss issues of staffing management, or human resources as it is more commonly referred to. The resources managers were asked to make recommendations on this subject to the executive team of the OSG. KB drafted these recommendations and circulated them to the resources managers for review. The will be sent to the OSG executive team later today.
• Work with Cindy on details of job description to replace Charles. I expect this will be posted any day now.
• Worked with Julie on formulating a package for review and signature by the Office of Sponsored Research to continue funding for year 2 of the OSG sub award to Caltech. Have requested Budget information from UW Madision for PMA and SRO package.

________________

Anand Sengupta:

• Last week I started looking at the effective distance cuts for the high mass CBC search. Preliminary results are available at http://www.lsc-group.phys.uwm.edu/cgi-bin/enote.pl?nb=iags5tdfindchirp&action=view&page=54

Laboratory Computing (Anderson)

LDAS Software Systems (Maros)

• Several problem reports were opened this week after testing bringing up LDAS on a system with many of the NFS mount points not being available.
• Conversion of LDAS tests to the TCL test model continues with the focus this week being on the MDC tests scripts. About 45% of the MDC tests have been converted.
• System tests were run using version 1.9.67 of LDAS. There were no outstanding conditions.
• Documentation has been expanded with several new web pages. There include a page for rsyncing builds and another on how to use the system test harness.
• The week long running of LDAS on ldas-test only had 9 datacond "no such symbol" errors.

LDAS System Administration (Anderson)

Caltech

(Dan Kozak)

• No report.

(Phil Ehrens)

• The usual certificate related tasks and user support.
• Ongoing support of MOU review process and data.
• Met with Albert Lazzarini and Dave Reitze to discuss issues discovered during the MOU review and the remedies and enhancements appropriate for next year.
• Replaced 12 fans in cluster nodes. There are currently 41 additional dead fans.
• Enhanced shasumcheck.tcl to make it OS agnostic and to support a blacklist of files that will be excluded even if they are part of a glob.

(Erik Espinoza)

• Performed LDAS-CIT kernel/condor pre-upgrade preparation:
  • Wrote rollback/forward plans
  • Staged config and rpm files
  • Deployed kernel to nodes, head nodes on cluster
• Built and tested kernel

MIT

(Fred Donovan)

• Upgraded 3ware driver data3; replaced 2 disks data3.

Livingston

(Igor Yakushin)

• Finished debugging LSCsegFind server/client version that allows to query for all active DQ flags, all versions, all ifos, for a given time interval. That would be useful, for example, in order to see all active DQ flags around the time of a trigger.
• Due to network problems at LHO, the replication from/to LHO was broken for several days. It is fixed now.
• New tapes arrived.
• Reconfigured x4500-1:/home with compression turned on. Reran rsync from dataserver:/home. It looks like compression reduced the disk usage at least by a factor of 5-6.
• First attempt to configure ilom on x4600 failed for some reason: after several reboots it still would not work although the correct ip address was shown in Bios. There were no such problems with x4500.

(Dwayne Giardina)

• Tape eject for shipment to CIT.
• Tape storage eject to be performed later today or first thing  tomorrow.

Hanford

(Greg Mendell)

• There are several issues with the next release of LDG 4.5 that I am working to sort out, but should have a prerelease out soon.

General Computing (Wallace)

MIT

(Fred)

• Some cvs issues (emvogil-3).
• Solidworks computer died again(genstor) temp replacement(inspiron 530) built - data transfer.
• RMA to genstor.
• Some purchasing.
• Printer/wireless issues.
• vsftp on tintagel to receive xp backups -- tests work well.
• Some ilog.

Livingston

(Dwayne)

• Registered 3 copies of Webdrive for XP users of WebDAV.
• Relocated an all-in-one printer/fax/scanner/copier from the conference room to the lobby area outside my office.
• Problems installing XP on a Dell for new hire mechanical engineer, finally resolved after a Dell tech replaced the motherboard.  ongoing installation of software on this PC.
• Received a repaired PQNode power monitor, installed in Computer Users Room.
• Had to tweak settings on a laptop for a presentation in the auditorium.
• More budget planning.
• Created a couple email accounts for new hires, created one new GC account.
• Several procurement items (monitors, backup HDs, etc).
• Other usual/unusual user support requests.
• Cleared spam trap.
• LLO mail summary for  27 September 2007 - 4 October 2007:

Rejected:  8,775(55 containing virus)

Accepted: 5,062

Total: 13,837

Hanford

(Christine)

• Finished setting up the computer to be the DNS server.  Copied the DNS files over and tested with nslookup.  It all seems to work.  Wrote an email to Caltech ITS host master requesting authority for the ligo-wa domain.
• Set up a new Sun Fire X2200 to be the new mail server.  Larry will be here the week of 10/14~ to help get the mail software going.
• Set up another X2100 to be the new web server.
• Arranged a phone conference for 10/8 with Lockheed Martin, PNNL and Amerion to discuss what to do about the backup network that has never really worked.  Sounds like Amerion and PNNL are still thinking the problem is with the fiber between LHO and PNNL which is Lockheed Martin's responsibility.
• Also sent an email to the Cisco engineer just to make sure there isn't something with my router configuration that may be causing problems with the backup network performance.
• Did a database backup of Primavera for the Advanced LIGO people.
• Distributed latest Matlab licenses and new software to users with personal licenses.
• Worked on FY'08 budget needs.  Sent an email to my contact at ESnet about network costs for '08.

Caltech

(Mike)

• Loaded a new Sun Server to host the LSC website.
• Worked with Larry on installing new Sun equipment in B/A server room# 18.
• Trouble shot wireless AP "poor performance" over in Wilson House. This was a problem with to many access points on the same radio frequency. After switching the channel things seem to be working ok.
• Ordered additional equipment for users and B/A server room# 18.
• Downloaded and tested new Service Pack "SP4.0" for SolidWorks & Explorer. I am now ready to update all our users here at CIT.
• Ran all End of Month ghost backups on NTSRV’s. I also updated the database on our Primavera server.
• Other onsite/phone user support and additional sysadmin tasks.

(Veronica)

• LIGO:  Processed video of the 40m magnet installation for DVD.  Work on a website for the upcoming NSF review.  Addressed an issue of server migration (docuserv).  Misc. web updates /user support.
• LSC:  Updates of the database of technical papers.  Misc. web updates.
• CaJAGWR:  Website updates /user support.

(Christian)

• Florence Kaufman: Created a backup of Florence¹s old workstation.
• Guy Fish: Setup laptop with our LIGO image until new workstation arrives for Guy.
• Configured two new systems with our LIGO image. The workstations are ready   to be deployed.
• Toner cartridge replacements- 3flr W/B and Irene¹s local printer.
• Did an inventory on printing supplies.
• Mike and I are testing the new MS Office 2003 SP3 update.
• Minor tweaks on the Windows SUS server.
• Other misc.: Continued onsite software/phone support.

(Larry)

• Worked a number of procurement issues. We've received some of the equipment and distributed a number of items. Working on a reorder of workstations and notebook computers. Spent time resolving some P-card issues. This looks like it will be a long process.
• Worked with Mike installing a number of servers into the racks. Some have been fired up and started the s/w installations. Working with Mike on getting a PDU issue resolved so we can get the disk units going.
• Still moving backup files from disk to tape. Performed the monthly user account backup.
• Worked a number of different issues with various users. Mostly hardware configurations and setups.
• Worked with ldas on some h/w modifications.
• Working on budget and documentation items.
• Worked with Shannon on a couple of his projects dealing with security.
• Setup a number of new user accounts.
• Working with Rod on different property issues.
• Some minor SUS testing and checking of client machines.
• Regular user support.

Advanced LIGO and Supporting R&D (Shoemaker)

Advanced LIGO Management

No report provided.

Advanced LIGO Systems

Modeling and Simulation

From: Hiroaki Yamamoto hiro@ligo.caltech.edu

Modeling and simulation (Hiro Yamamoto)

• John Cortese has arrived and will start working on October 5th in the simulation group.

e2e weekly meeting

• Sany summarized his simulation works of the MC system, using Mark Barton's triple suspension and AdvLIGO HAM. He compared the result with LIGO I performance and AdvLIGO requirement. Osamu said that he has almost completed the setup of the full advanced LIGO seimulation using e2e, and he will be able to show some result at the next meeting.

Static IFO simulation (Hiro)

• The dependence of the loss on the mode mismatch by the error of ITM ROC and RM ROC was calculated for MSCC and SCC. (~hiro/talks/ ITMROCvsLoss.pdf).
• Some contradictory result came out of the SIS simulation, compared with the Yi Pan's calculation.
• At the COC meeting, some suggestions were made to investigate the result, including the validation.

Higher performance computing (Melody)

• Melody compared the performance of FFT calculation using FFTW, Intel Math Library (MKL) and AMD Core Math Library (ACML).
• MKL out performed FFTW (setup using MEASURE option) when 16 cores are fully used on menkar.

There is almost no difference when only 4 threads are used.

• ACML does not fully utilize the multi core system to speed up the FFT simulation (at least, any part of the document mention anything about this, except how to better utilize thread in general).
• The BISO changes in menkar (run at 1GHz when idling and run at 2.6GHz when busy or always run at 2.6Ghz) did not affect the speed.
• For this comparison, gnu compiler and intel compiler were used. Intel compiler showed 5~10% speed increase.  The FFTW code is optimized in a special way and this comparison will not be a good bench mark.

Mechanical Simulation for advanced LIGO (Sany and SLU team)

• Confirmed that BinarySource primitive and IFO primitive work under the most recent e2e release by reproducing Jeff (Hiro's 2003 SURF student) computation that he made under e2e version 1.8.
• Continued AdvLIGO Input Mode Cleaner simulation. Computed MC residual motion seems to be too small. will look into the problem.
• Richard modified Mark's mathematica code for the AdvLIGO quad suspension with violin dynamics so that the actuation force would be output. The resultant state space matrix will be tested shortly.

Prestabilized Laser

From: Peter King <pking@ligo.caltech.edu>

• Some problems were experienced with the injection locking of the high power stage to the front-end laser.  At first it was suspected that the problems were due to the locking photodetector but eventually the problem was traced to the locking servo.  The gain of the locking servo was increased.  The injection locking works well now and is reliable.  The optical table can be tapped without any detrimental effects to the locking.
• A vacuum chamber used for power stabilisation studies was leak checked as it had been up at air for a long period of time, plus new items were installed inside.  The balanced detection experiment will be set up without a beam splitter to see if the beam splitter is the cause of the excess pointing fluctuations that may limit the sensing of the power stabilisation photodetector.
• An initialisation error in the front-end laser control software was found.  A fix was written and has been succcessfully tested at LZH.

Control and Data Systems

From: Rolf Bork rolf@ligo.caltech.edu

AdL SUS Noise Prototype

• Wiring diagrams for the temporary controls have been completed and put in the dcc. The drawing number is D070448-00-C.
• The UK group will receive 8 sat amps tomorrow. They are fully stuffed and ready to mounted in boxes.
• The first UIM coil driver board and the monitor board have been tested. There is a funny hump in the transfer function of the UIM board between 10Hz and 100Hz that needs to be cleared up. A full UIM unit should be ready for shipment by the end of October.
• The Top coil driver board is ready for test.
• The PUM board should be back by the end of October.
• The balance of the monitor boards should be shipped from the fab house in mid-November.

ELIGO OMC Controls

• Earlier this week, we put the majority of the chassis in place for the test of the OMC Tip/tilt structure.  Work is ongoing to prepare this for Bram's visit next week.
• The AA and AI chassis for the OMC are ready for installation in room 56. This includes the replacements for the units installed to test the suspensions this summer. All other suspension electronics are ready for operation.
• Began the process of uploading final design baseline data for the OMC electronics to the Advanced LIGO wiki.
• Manufacturing is under way of 15 custom in-vacuum cable assemblies for general use in the ELIGO upgrade.
• We are building the custom in-vacuum harnesses to be used on the glass bread board for the OMC and also for the suspension interfaces.
• Now that the individual OMC electronics modules have been characterized, we need to hook blocks together and take baseline data on the assembled systems
• Working with Rusyl and Richard to get cable lengths and electronics locations for the installations at LLO and LHO of the OMC electronics

ELIGO SEI

• Jay and Alex at Stanford next Monday/Tuesday to help them through a few problems with the prototype going to Boulder.
• Ben at Stanford late next week to for last of testing.

Seismic Isolation

From: Ken Mason kmason@ligo.mit.edu

BSC Seismic Isolation Assembly and Test

• The SUS group is working on the quad. Next week they should be complete and we can start the integrated testing.

Single Stage HAM Seismic Isolation Assembly and Test

• The assembly stand has arrived at HPD and has been assembled. The test stand arrives tomorrow. We have begun preparing the floor in preparation for the stand to arrive.
• Zimmerman Metals has delivered the three large plates to HPD. Stage 0 is being lifted onto the assembly stand to begin assembly on monday. We visited Zimmerman's on thursday to inspect the final three plates before they are shipped directly to Astropak for cleaning. The plates show signs of staining which we did not expect. They will send us sample pieces so that we can determine what is causing the staining and develop a process to clean them.
• We also visited Rogers wire EDM service to see the final three blades in process. They will not be complete until 10/19, however that should'nt be a problem as the cleaning is quick for these parts.
• Cory, Myron, and Jeff Kissel will arrive next week to begin the structure assembly.

Suspensions

From: Norna Robertson <nroberts@ligo.caltech.edu>

• Continued working on update of LSC authorlist.
• Further work on SUS budgets including change request.
• Provided requested transfer functions (force/torque in to displacement/angle out for 6 degrees of freedom) for OMC.
• Worked on pitch frequency queries for quad noise prototype

From: Janeen Romie <janeen@ligo-la.caltech.edu>

• Still working budgets and ETC with Norna.

Recycling Mirror Suspension

• Nothing significant to report.

Output Mode Cleaner Suspension

• The initial report from the welding specialist says that the structure welds have not met the requirements. We will go forward with this structure until we receive the report. Jay reports that the OMC suspension electronics are from last summer (have the old AA and AI chassis.) So, he will make the electronics like Enhanced LIGO today. Chris is getting the structure to the machine shop for the final machining today. He'll start to assemble it on Monday for Sam to suspend his bench on Tuesday when he gets back.

Earthquake Stops

• Nothing significant to report.

From: k mailand kmailand@ligo.caltech.edu

• I have started a new design for the zero expansion pick off telescope/hartman sensor. The direction after a few meetings with Phil, Riccardo, Aidan, and Mike Smith is to make it entirely out of  Zerodur / Invar material. To mount it with a 4 wire suspension, and a thermal box around it is the current approach.
• There will be issues of handling, setup access, and alignment to discuss.
• Testing the faraday 4 wire style damper is in Phil Willems lab, is in progress.
• The preliminary assembly of the installation arm tool is in progress, also work on a test setup has started.

Core Optics

From: Bill Kells kells@ligo.caltech.edu

• I have been in preparation for the post S5 task of conducting photographic imaging of the LHO TM HR beam spots. There are now several aspects to this:
  • Archival, to have a suite of good standard hi res images for future comparison.
  • Simultaneous (that is at the same VPs uncovered for the photography) "scatterometer" measurement of the [unimaged] scattered light intensity.
  • Independent check of the interferometer "boost" by performing 2. (above) with single arm lock as well as full ifo lock.
• The full deployment of measurements will be initiated by Cheryl Vorvick (who has previously done all the Hi Res photography). I am planning on visiting LHO, approx. Oct 16-19 for the boost measurement, selected repeats, and as much analysis as possible.

Auxiliary Optics

From: Michael Smith smith@ligo.caltech.edu

OPTICAL LAYOUT FOR STABLE RC

• Mike completed a preliminary layout of the stable recycling cavity, based on a power recycling cavity length = 55.815 m, and a signal recycling cavity length of 57.41 m, with a Schnoop assymetry of 50mm. The horizontal BS wedge of 0.8 deg will be increased to approx 1.0 deg in order to increase the separation of the BS ghost beams from the main beam. Several other variations will be investigated in order to minimize the wedge angle of the BS.

HARTMANN/PO TELESCOPE CONCEPT

• Conceptual design discussions are ongoing within the AOS group. Ken is in the process of making a preliminary concept drawing of a suspended telescope with Zerodur/ULE spacers.

OUTPUT TELESCOPE STABILITY

• Phil and Aidan have determined that the spacing between the mirrors of the output Telescope, which will be used for inserting the Hartmann ITMY sensiong beam, must be controled to < 30 micrometers. This may be accomplished by measuring the distance between HAM4 and HAM5 optical tables with a 2-wavelength interferometer and controlling the position of the mirrors with the SUS OSEMS.

FY08 R&D COSTS

• Mike and Phil submitted estimated R&D costs for the various AOS subsystems. The major new items are prototypes of the Hartmann/PO telescope with a wavefront error < lambda/400, ETM Telescope SUS, and a low-pointing noise optical lever system.

Input Optics

From: David tanner@phys.ufl.edu

Luke:

• broke one magnet disk (of 7) for the FR for LHO (negative progress).
• shepherding eLIGO parts through manufacture, clean, & bake.

Muzammil and Rodica:

• We measured the magnetic field strength of the FR as function of axial distance for the new FR assembly and performed measurements of the rotation of polarization for TGG crystals from two different vendors: IAP and Northrop Grumman. TGGs from Northrop Grumman provide higher rotation than the crystals from IAP for the same field and thickness. In the advanced LIGO Faraday-rotator magnet, the separation between the locations of the two NG TGGs that provide the optimum rotation is 3 cm. This is large enough to conveniently fit all the three crystals (TGG+QR+TGG) and to have some room for fine tuning the rotation.
• Muzammil also simulated numerically the field due to all 7 disks, and found that it matches the measured magnetic field profile. Based upon this, he determined that a six disk combination can also be used. Therefore we can assemble the FR for Hanford with the available resources. 
• We are also looking into the availability of magnetic disks from US sources.

Kate and Antonio:

• We changed the FI configuration once more (TFP+FR+TFP+DKDP) and took a set of measurements in vacuum for comparison with the previous two setups (CWP+TFP+FR+DKDP+CWP and CWP+TFP+FR+CWP+DKDP).
• The result is a drastically worse isolation ratio: 15dB compared to the previous 30dB and 44dB. The thermal drift, however, is not much different than before: 100 urad in the horizontal and vertical directions. We conclude that CWP+TFP+FR+CWP+DKDP is the way to go.
• We are taking inventory and making arrangements for the eLIGO FI assembly in the optics lab.

---

For additional information about this report, contact Albert Lazzarini or Phil Lindquist