The LIGO Executive Committee Agenda for Monday September 12, 2005 will be:
(Meeting time: 10:30 am Pacific Time)
Special Items:
LATE BREAKING NEWS from Mike Zucker (Thursday night): “We got it locked!”
No report
>From: Ed Chargois <chargois_e@ligo.caltech.edu>
>From: Linda Turner - turner@ligo.caltech.edu>
>From: Cleveland Mak <mak_c@ligo.caltech.edu>
>From: "Cronin, Holly" <Holly.Cronin@caltech.edu>
>From: "Brambila, Ruth" <Ruth.Brambila@caltech.edu>
>From: Florence Kaufman <fkaufman>
>From: Gina Salone <gsalone@ligo.caltech.edu>
>From: Ed Jasnow <jasnow@ligo.caltech.edu>
>Irene Baldon
>Julie
Hiroto jhiroto@ligo.caltech.edu
>Dorothy Lloyd
The Proposal for an Extension to FY 2007 and FY 2008 and Supplemental Funding for LIGO Operations was previously reported as submitted to the NSF. The NSF requested additional material. Contributors to the Annual Report have been provided additional material. The assembled material has been provided to Stan for review. There is some question concerning the relative depth of coverage in the various sections.
Change Request CR-050008 for funding to upgrade the LIGO Document Management System was approved. We are preparing a statement of work and purchase order.
>From: Cindy Akutagawa <cindy@ligo.caltech.edu>
>From: Bill Tyler tyler@ligo.caltech.edu
No report.
Activities have centered around the installation of two acoustic enclosures on IFO REFL ports. ISCT7 on the 2k received its enclosure last week, so this week, light pipe connections inside and out the enclosure were made, and the IFO relocked. On the 4k, the ISCT1 enclosure was craned in, light pipes installed and the IFO quickly relocked.
Some highlights from the last two weeks of elogs are linked below:
A 9/17 showing and discussion of part one of the three-part series "The Elegant Universe" comes next on LHO's World Year of Physics calendar.
LLO weathered Hurricane Katrina well. We are
extremely fortunate that all staff and families have checked in safe, although
not everyone has been able to return to their home yet and some still don't
have power. All staff did report for work this week.
We're especially proud of the emergency
response contributions by LLO staff, contractors and families, who reached out
to those less fortunate in the wake of the disaster. LIGO employees have been
volunteering at evacuation centers, taking in refugees, and running food,
water, generators, and fuel to those in affected communities since the disaster
hit.
LLO is now open for business and back on task
preparing for the S5 run. However, due to the immense devastation in
As a result we have cancelled our normal
influx of commissioning and collaborator visits from outside institutions until
we can secure housing for them. This severely impedes our preparation for
science operations. We are working to secure temporary accommodations and hope
to resume hosting limited visits soon.
The LLO vacuum system was put in protective
mode by shutting the main gate valves in advance of the hurricane. Power was
restored by DEMCO to the LLO substation after only about one day, allowing
resumption of level control on the cryopumps and
restarting of ion pumps. The beam tube gate valves were reopened on Thursday
9/1 after pressures, cryopump level controls and
residual gas composition showed a clean bill of health.
The buildings and infrastructure sustained
only minor damage. Some flashing was loosened on the X end station and a wall
panel on the exterior of the LVEA was blown away; LLO staff improvised a patch
while we try to locate a repair contractor. Downed trees crushed the perimeter
fence in a few places but everything was cleaned up and repaired by Tuesday.
Our automated fire alarm reporting had been
cleared through a New Orleans-based service, which no longer exists. We
instituted a manual fire watch protocol on site and engaged another
contractor. They could not interface to
existing hardware and had to install replacement interfaces. The system just
came back online today (Thursday) and we are now reconnected to the fire
department.
Phone service has been working since the
power was restored. Long distance and local circuits are overloaded, so please
be patient and retry your calls a few times. Generally you will get through in
a few tries.
Our gigabit internet fiber was severed by
fallen trees between Livingston and
Recovery of interferometer operation has just
started after CDS was brought back up. The most significant direct damage from
the storm was electrical damage to GPS antennas on the LVEA roof. Replacements
arrived Tuesday. A possibly related fault was later found in an IRIG-B timing fanout unit for which we had no spare; there is a
workaround patch in place while we track down a proper replacement. Some disks
and at least one CPU didn't wake up, as is typical for power outages.
The PSL and the Mode Cleaner are operational
and stable. Both single arm cavities have been locked but remain shaky, due to
an undamped steering mirror and continuing
CDS crash problems. The problem with the
steering mirror was found to be due to the burnt cable that feeds power to the
OSEM. We expect to uncover other minor
bugs but are now working through systems one by one.
LATE BREAKING NEWS (Thursday night): L1 has locked and
reached common-mode. Still working on power up but looking good!
Working on background
material for webpage.
The LLO emergency action plan was executed in
preparation for the shutdown. Other than some minor hardware problems with the
security system associated with the power outage, no serious safety issues were
reported.
1) HPLF news: No HPLF damage due to Katrina has been observed, although I have not been able to turn on the laser since the fire alarms has not been working.
2) REFL port beam stabilization servo: We have been waiting for the Piezo Jena PZT system to show up. Today Thursday Sept. 8 we received two out of three parcels containing the PZT driver electronics. We are still waiting for the third parcel containing the PZTs.
1) Got quotes for Foundary switch service contract.
2) T3 disks u1d2@t3-1, u1d9@t3-3, u1d7@t3-7 failed and were replaced with disks from the spare T3. Replacement disks were ordered from SUN. No data loss.
3) 3510 disks 1,6,7 failed; the replacement disks from SUN are expected today. No data loss.
4) 1 disk failed in datagateway2 ide raid array and was replaced with a spare. No data loss.
5) metaserver's primary disk is failing. Working on restoring the metaserver.
6) Having problems with LDR: LSCdataFind cannot query the server.
7) Executed yum update on ldas-grid, ldas-pcdev1 and the nodes.
8) ASA is sending me the replacement power supply module for node39.
9) Ran samfsck on /frames, /archive, /dmt. Several files were corrupted on /frames due to the power outage and were replaced by Alex with copies from fb0.
10) The contractors bidding for LDAS move got an extension till the end of this week (originally the bids were due last Wednesday but were not submitted due to the hurricane).
see also the CDS weekly meeting minutes in the commissioning archives
Rolf Bork
Alex is continuing work on the Fast ADCU changes. These should be complete by next week.
Jay Heefner
Refl Beam Stabilization
Ben Abbott
LSC RFPD
Todd is stuffing boards to complete the delivery of new RFPDs to the sites. He has been held up by some components that are discontinued. I found a place to get them, and ordered enough that we won't run out of them anytime soon. They will arrive on Monday, and we can finish the stuffing and testing of these remaining three units.
Fast Shutter
The second prototype fast shutter was completed this week, I will begin testing later today.
ISS PDs
I'm going to the anodizing shop to pick up the ISS PD bodies today.
no report
nothing significant
GariLynn Billingsley, Liyuan Zhang, Bill Kells
The high resolution absorption measurement has been repeated, the peak
absorbers appear to average in the hundred ppm range,
making the total absorption of the coating in the 2ppm range. We are now
looking at the fundamentals of the measurement to see if we can adequately
capture absorption from very small particles with this method.
The scan was repeated near the edge of the optic, statistics were similar, so we can easily use this less "valuable" real estate to try different approaches.
The issue of contamination of optics during shipment has been raised, with a concern that our cases may be being opened, we are looking into some sort of tamper evident sticker. Also we are looking at the integrity of the cover and case in which these two shipments occurred.
Steve successfully completed the Escape from Alcatraz Triathlon on August 14, placing second in his age group. Congratulations, Steve!!
Ric brought over Professor Tang, who wants to
build a prototype interferometer, similar to the 40m, in
No report.
This week we began removing the LIGO 1 Stack, Support Table and Optics
Table. This was in preparation for arrival of the solid stack and the quad in a
couple of months. This was also done so that the system could be returned to
vacuum so that the PSL characterization could be completed.
Rich also continued his study of using rubber pads to increase the available passive isolation of the seismic stacks. These rubber pads provided isolation at lower frequencies. Reduced isolation at higher frequencies was observed which and the table motion was not coherent with the ground motion at these frequencies. Some possible causes for this are acoustic noise of the rubber might be acting non-linear at small compressions. The second suggestion was from the engineer who recommended the rubber.
(Biplab) Completed diffraction calculations for Laguerre-Gauss modes for a range of mirror radii (15-18 cm) using matlab FFT code. The results show again (as for Hermite-Gauss modes) that the calculation of loss using simple-minded 'clipping' approximation or 'Truncated Gaussian' approximation always underestimates the loss calculated by FFT. This also agrees with such observation made by Bob Spero for LIGO-I cavity [Ref: number-less memos of 1997 & 2001].
All results for Hermite-Gauss and Laguerre-Gauss modes can be accessed from here [1 file for 1 mode. Losses vs. Mirror Radii] http://www.ligo.caltech.edu/~bbhawal/Blair/
(Hiro) Together with Mike Smith, I started to study the effect of the scattered light from various points. Numerical analysis can be easily done using twiddle, but analytic formulation will also be pursued.
(Monica) Transmitted light curves have been reproduced in e2e framework with different relative mirror velocities in order to compare them with raw data. In particular one simulation has been done using values of mirror-speed obtained from raw data by a parabolic fit. The agreement seems to be not so bad: checking is in progress.
(Hiro) Fast DRM (Dual-Recycled Michelson) code development continues. End user supports, including maintenances of examples to keep up to date to be compatible (or to be reflecting new features). Sasabayashi, Prof.Yoshida's graduate student, showed interest in studying the modal model version of fast DRM. He will study the corresponding formulation of FP first.
(Melody)
Chatterji:
QSCANs are available for all RDS_R_L1 channels around the time of the 10 most significant triple coincident events identified by WaveBurst during S4: http://ldas-pcdev1.ligo.caltech.edu/~shourov/newscans/
Consulting with JunWei Cao on his DMT implementation of Q Pipeline.
Preparing a document to summarize coherent network analysis activities within the LSC burst group. This document will serve as a reference to identify the goals and projected timescale of various efforts, to identify the similarities and differences between efforts, and the guide the selection of data sets for benchmarking and comparing coherent searches within the context of the LSC/Virgo joint data anlaysis working group.
Identifying the work that remains to be done for a planned PRD publication by the LSC/Virgo joint data analysis working group comparing various burst analysis algorithms and detector networks.
Updating documentation and calibration information for PEM coil magnetometers in order to support intersite correlation studies. Sample spectra from S4 indicate that L0:PEM-COIL_MAGZ was not operational: http://ldas-pcdev1.ligo.caltech.edu/~shourov/magnetometer/
Mendell:
I have been working on changes to the StackSlide Monte Carlo simulations, to speed these up significantly. The changes are nearly complete and by next week I should be able to report on testing of these changes. The review of the code continues.
Shawhan:
Lazzarini:
Writing a conference proceedings paper for PASCOS2005 Contributed to the final draft of the stochastic S3 PRL after receiving referees' comments.
LDAS
Identified a second source of zombie threads in the C++ layer of the diskCackeAPI, actually inherited from the genericAPI C++ source code. It looks like this has ended all cases of the zombie threads from the C++ layer. The Tcl layer still ocassionally thinks a thead is in a zombie state if it has run for more than 1000 seconds. We are looking further into why theads are running for so long, but is may just be statistical fluctuations in the thead scheduler causing a thead to be pushed back in priority. Further investigation is still needed.
Continued efforts at compiling LDAS for Solaris 10 and Fedora Core 4; after reviewing several core files from running LDAS, it was discovered that the STL library from GCC 4.0.1 is not thread safe. Most of the week has been spent in trying to compile the latest version of STLport (version 5.0 release candidate 5). When trying to compile ObjectSpace with the latest version of STLport there are some unresolved externals. No issues have yet been seen when recompiling Xerces and lam with the latest version of STLport.
Continued work on integrating TclGlobus GSI sockets into LDAS, starting with the controlMonitorAPI server/client. No issues have been discovered with using TclGlobus with the server side (which is based purely on TCL). However, TclGlobus has been at issue with integrating it into the client side which is based heavily on TK and the wish shell. Simliplied example test cases for server/client Tcl/Tk programs were developed to get to the root of the problem with Tk. We have found that we can stop the tight spinning of the client example by adding a Tk widget to the script (see TclGlobus report below).
Conducted the system testing for LDAS on version 1.7.24 and updated the CVS web results pages Developed new test scripts to isolate TclGlobus interface in the "wish" shell for debugging purposes.
TCLGLOBUS
Worked on the integration issue of XIO TclGlobus (nonthreaded version) and LDAS cmonClient softwares. Both are using tcl/tk version 8.3.5
The problem is when LDAS cmonClient (wish) is in idle state, TclGlobus event handler consumes 100% of the CPU cycles causing LDAS cmonClient can not perform any other tasks. TclGlobus event handler mechanism specifies the interval time to poll Globus events. Under tclsh, the interval time works properly, but under wish, the interval time doesn't have any effects.
Based on Kent's suggestion, we run a small client/server program and we also added a button on client wish program, then TclGlobus event handler mechanism worked properly (it's using the pause interval we've specified).
Analyzed strace client logs produced from tclsh and wish (no widgets). The difference is tclsh uses the following function during execution: clock_gettime (CLOCK_REALTIME, {1126126878, 24219000}) = 0
But, wish doesn't use the above function during execution. I'm still learning the difference and I still have no explanation why tclsh uses the function, but not wish. However, by adding widgets on wish, it behaves like tclsh program.
Still working on analyzing valgrind client logs.
OSG/GRIPHYN/IVDGL
Inspiral work flows on OSG - ITB:
GUMS and PRIMA configuration:
On-going monitoring and system administration:
Caltech
(Dan Kozak)
(Phil Ehrens)
(Stuart Anderson)
MIT
(Keith Bayer)
(Igor Yakushin)
(Greg Mendell)
All Level 3 RDS frames with GPS start-time greater than or equal to 809464832 (Aug 30 2005 12:20:19 PDT) no longer contain H1:LSC-AS_Q or H2:LSC-AS_Q. The Level 3 RDS channel for astrowatch data now is:
|
H2:LSC-DARM_ERR |
1 |
|
H2:IFO-SV_STATE_VECTOR |
1 |
|
H2:IFO-ACTIVITY_TYPE |
1 |
|
H2:IFO-ACTIVITY_STATE |
1 |
|
H2:IFO-ACTIVITY_INDEX |
1 |
|
H1:LSC-DARM_ERR |
1 |
|
H1:IFO-SV_STATE_VECTOR |
1 |
|
H1:IFO-ACTIVITY_TYPE |
1 |
|
H1:IFO-ACTIVITY_STATE |
1 |
|
H1:IFO-ACTIVITY_INDEX |
1 |
(Ben Johnson)
(Keith)
(
(Christine)
(Veronica)
(Christian)
Gina Salone: Installed new CD Writer on her system.
Calum Torrie: Removed 5 different adware and spyware running on Calum's workstation.
Julie Hiroto: Replaced toner cartridge on HP 2550 printer.
(Mike)
(Larry)
These all took time to track down and having more specific information other than someone saying they are not getting their e-mail will make things easier to resolve.
|
Mail Statistics |
September 08, 2005 |
|
Rejected Messages |
16,271 |
|
Virus Messages |
1,148 |
|
False Positives |
149 |
|
Accepted Messages |
11,488 |
|
Total Messages |
27,759 |
from Carol
Wilkinson
Progress Updates
Progress updates for Advanced LIGO subsystem development for the period from July 1 through August 31 are complete for all subsystems with the exception of Suspensions, which will be completed on Monday, Sept. 12. Updates will be posted by Thursday, Sept 15.
Meetings & Reviews
Future near term planned meetings & reviews are indicated in the table below.
Report from the 40M DC Readout Review held July 19, 2005 is available: LIGO-T050168-00-R
Changes since last report are listed in blue.
|
Date |
Sub sys. |
Review |
Topic(s) |
Enabling event(s) |
Schedule motivation |
Status |
|
Jul 11-13 |
SYS |
SYS Mtg |
CDS infrastructure & HAM
Isolation Req’s |
|
|
Report in progress |
|
12-Jul |
SUS |
PDR, Review 2 |
Electronics req & design;
Focus is on the front end electronics ( |
|
|
Report in progress |
|
~Sep |
SUS |
PDR, Review 3 |
Quad design |
Completion of the quad controls prototype assembly; |
timely transfer, to RAL & UB efforts, of lessons learned from the controls prototype |
|
|
Oct 19 |
SUS |
SUS PDR Review 8 |
Ribbon/Fiber/Ear/ Bonding PDR |
Completion of the ribbon, fiber, and ear and fabrication
and bonding design and processes |
|
Panel and date selection under way. |
|
~Oct |
SEI |
HAM Critical Design Review |
Recommendations w.r.t.
HAM prototype development based on ETF results |
Completion of SEI/BSC critical design reviews;
LSC review of ASI HAM configuration design |
Delay until requirements are revised. timely decision on
proceeding with SEI/HAM prototype |
Delayed from Aug. |
|
~Oct |
SYS |
PDR, Review 1 |
Engineering & Implementation ('generic') Requirements; |
completion of generic requirements definition; completion of first draft of ICD; revision to optical layout; establish integrated opto-mechanical equipment layout |
timely system level definition enables/helps define subsystem reqmnts & design |
|
|
~Nov |
SUS |
PDR, Review 4 |
Quad Installation |
Completion of installation at LASTI |
Inform the |
|
|
~Dec |
SUS |
PDR, Review 5 |
Triple design |
Available SUS/US staff |
Enable SUS/US final design phase |
|
|
~Dec |
SYS |
PDR, Review 2 |
CDS Infrastructure |
Sufficient CDS requirements & concept work (also
7/11-13 mtg) |
CDS Infrastructure is key to subsystem electronics req. |
|
|
~Jan |
IO |
PDR Review 1 |
PDD, Faraday Isolator, modulators, mode
cleaners, mode matching design, Mach-Zender |
SYS PDR? |
|
Work delayed on FI, allows more systems to be reviewed |
|
~Jan 25 |
AOS |
AOS DRR/CD Review 1 |
Stray light control, |
SYS PDR? |
Delay stray light control review until other
systems can be reviewed at the same time. |
Delayed from Oct. to allow review of add. systems. |
|
~Feb |
SUS |
PDR, Review 6 |
quad controls prototype test results |
completion of LASTI testing |
timely incorporation into final design effort on the noise prototype |
|
|
~Feb |
COC |
PDR Review 1 |
Metrology, handling fixtures |
Review
and select vender and in-house
metrology |
Need handling fixtures for |
Work delayed |
|
~Mar |
IO |
PDR Review 2 |
Adaptive mode matching, Mode Matching Telescope |
Determination of whether a stable recycling
cavity will become part of the |
|
Waiting for stable RC decision |
|
TBD |
AOS |
AOS DRR/CD Review 2 |
Thermal Comp., Photon drive |
SYS PDR? |
|
Moved forward for timely finish of AOS CDR’s |
|
TBD |
SUS |
PDR, Review 7 |
BS, FM/ITM SUS design |
design work completion (has yet to start on FM/ITM, not mature for RM) |
|
|
|
~May |
COC |
PDR Review 2 |
Cleaning Process, Optics prelim. design |
SYS PDR? |
|
|
From: Ken Mason kmason@ligo.mit.edu
|
Assembly |
Status |
|
Top Assembly Components |
RFP Complete, awaiting bids |
|
Stage 0-1 Spring Assembly |
ASI has been issued a purchase order to soften the springs
for better performance at 10 hz. The analysis
portion is complete. Redesign of the solid model is in process and is
expected to be completed by 9/23 |
|
GS-13 Pod Assembly |
Geophones and seismometers are in house. |
|
Stage 0-1 Kinematic Lock |
Tooling design required prior to soliciting bids. |
|
Stage 0-1 Actuator Assy.'s |
Actuators and position sensors have been received. |
|
Stage 0-1 Standoff Pin |
Solidworks part files exist for
the standoff pin and alignment towers. They will require a dimensioned
drawing and checking prior to soliciting bids. |
From: Jay Heefner <jay@ligo.caltech.edu>
From: Janeen Romie romie_j@ligo.caltech.edu
From: ctorrie <ctorrie@ligo.caltech.edu>
We (Mark, Helena and I) suspended the controls prototype quad for the first time on Friday. The arrangement was a single chain, with short term changes made to match the "new flexure" theory. Now that this has been proved we plan to make the temporary fixes more permanent and apply the correction at all of the stages! The re-designs have now been completed and after review the workshops will start on them. At present we hope to be ready for the next build in a week to 10 days. In the mean time Mark, Johanna and I have been arranging the existing quad to accept the local control osems.
http://www.ligo.caltech.edu/~ctorrie/LIGOMOVIE/QUAD/
Laurent and Rich are visiting next week to assembly the 2nd mode cleaner. Bob and I have prepared all of the parts and they have been cleaned and baked ahead of their visit.
The second quad structure should be finished and ready to ship to Stanford by the end of the month.
From: Ken mailand kmailand@ligo.caltech.edu
I will send one of the quite chiller flow meter mounting brackets to Cheryl at LHO tomorrow for her to ok. I'm looking over the HAM SAS drawings, for fits and dimensions/tolerances etc.
From: Rolf Bork <rolf@ligo.caltech.edu>
The quad suspension software is in progress. The basic Epics software is running, along with a major portion of the front end code. The ADC/DAC I/O cards have not yet arrived, so I am still using the PCI reflected memory card to simulate the I/O. The quad uses 96 filter banks, into which I loaded 3 filters each for initial testing. The code runs in approx. 18usec in this configuration. I have ported the data acq. code into the quad software, but I still need to port and add the code which handles the GDS test/excitation points. The rack mount computer, which will run the code at LASTI , is due in next week. I believe the DAC boards will also be in next week and the ADC the following week.
From: Helena Armandula ahelena@ligo.caltech.edu
From: Bill Kells <kells@ligo.caltech.edu>
Now that PI has become an ongoing "feature" of AdL
the concomitant work on it is never ending!
I am making a last ditch survey of the full recycled theory this week to
review with Braginsky before he leaves (tommorow). Also am in the throes of reviewing another
[revised]
From: Peter King pking@ligo.caltech.edu
Two more high power photodetectors were assembled. Unfortunately one encountered a problem with the -15V regulator and will have to be dis-assembled.
A mounting block for the Innolight NPRO was drawn up. I was also looking into a Hobb's meter to help keep track of the number of hours the laser would be on. Whilst I was told that this function is in the laser, it is not user accessible which doesn't make it particularly useful.
From: Michael Smith <smith@ligo.caltech.edu>
Met with Carol Wilkinson and set the date of Dec 1, for distributing the
documents for the CDRs for the following subtasks: Optlev, Pick off mirror/
Aabeg completed the project and submitted a final report.
Shasta completed the BRDF project and submitted a final report.
Hiro is helping me analyze the scattered light noise for the ADLIGO signal recycling configuration.
From: Riccardo DeSalvo
desalvo@ligo.caltech.edu
Ilaria
I assembled in Ansys the four HAM SAS inverted pendulum legs between the two tables: including all details of the main flex joint and the small flex joint. Since the top table (without the stiffeners) is 20 mm thick and too flexible, when I apply a force it bows too much, so I changed the thickness to 40 mm. Starting the load/frequency study and the transfer function production to estimate the counterweights.
The aim is to bring the IP horizontal attenuation beyond the 80 dB limit.
Valerio
The transfer functions matrix of HAM SAS that I am obtaining from the SimMechanics model of the HAM-SAS is in good agreement with the experimental data taken on the prototypes. In the next days I am going to add the sensors and actuators intrinsic noises and design a simple position control system to evaluate the controllability of the HAM-SAS.
Alberto, Virginio
Last week we got very interesting results. With the newest measurement setup - basically new accelerometers and their drivers and an ad hoc built system to inject noise directly at the base frame of the blades - we succeeded in our aim. We observed the expected behavior of the compensation rods in the transfer function of the MGAS filter. The rods demonstrated to be able to compensate or to overcompensate for the inertia of the spring depending on the amount and position of the counterweight. With three rods, and no additional counterweight, the TF has saturation level at 70 dB and the typical dip of overcompensation, when the overall center of percussion is moved too far out from the shaking point. Adding counterweights to the rods we confirmed that the dip moves back towards lower frequency and the saturation level raises back to 50 dB. Disconnecting one of the rods (to reduce the compensation) and no added counterweights on the other two, we observe attenuation saturation again close to 70 dB, but with the profile characteristic of undercompensation the c.o.p. effect. Analysis of the TF phase confirms that the TF phase of the under and over compensated cases differ by exactly 180 degrees, the expected minus sign. Hints of 80 dB attenuation observed. We are working on the fine tune of the TF optimizing the counterweight for best compensation. More information is going to come from a further analysis, mainly on the phase of the TF which pinpoints the critic point of best compensation. We have also to work on mitigation of the noise coming from the whole system resonances (sensors and mechanical system).
Gaudete Homines
The above result means that the passive Vertical
attenuation of HAM SAS is likely to match the 80 dB of horizontal
attenuation. Coupled with the 300 mHz
GAS tune already demonstrated, HAM GAS passive attenuation is now expected to
substantially exceed the Ad-LIGO requirements. Riccardo.
Francesca:
I assisted Alberto and Virginio that took over my equipment. I started the analysis of the hysteresis data that I took last week.
Maria Paola
I started to work with the stepping motor, mounting the switches,and connecting the various wires of the motor in an appropriate way so as to make it work. Afterwards, I directly connected the motor to the power supply, and also through a resistance and a capacitor: in this last case the motor seems not always to work properly, since a certain input voltage and capacitance are required for the motor to produce steps. Therefore, I'm trying to figure out which capacitance and input voltage are the best choices, reminding that the capacitance should be as lower as possible to avoid the out gas in the vacuum, and for this reason a bigger transformer (which means a bigger input voltage) with a lower capacitance could be a good solution for the vacuum.
Chiara
I worked in the machine shop to complete the final piece for the class I took there and to help Alberto and John to make same mechanical parts for their experiments. We made new cables for the two accelerometers that we use for the measurement of the transfer function.
Juri
I wrote a short note in order to summarize my results for the calculations
of diffraction losses in LIGO-I and Advanced LIGO (available at http://www.ligo.caltech.edu/~jagresti/Diff_Loss/).
My evaluations seem in agreement with the FFT results by Dr. Bhawal. Moreover I'm
working on some investigations on the nearly-concentric Mexican Hat cavity
which will be the future development of our experiment.
For additional information about this report, contact Stan Whitcomb or Phil Lindquist