Weekly Report for Week Ending June 10, 2004
The LIGO Executive Committee Agenda for Monday June 14, 2004 will be:
(Meeting time: 10:30 am Pacific Time)
- Announcements
- LSC Issues (Saulson)
- Comments on Weekly Report
- Field Change Orders/Contingency Liens/Change Requests
- LIGO Lab Operations
- Administration (Lindquist)
- Sites (Raab, Zucker, Shoemaker)
- Commissioning (Fritschel), Detector (Coyne)
- Campus Research Facilities
- Weinstein (40 Meter)
- Libbrecht (TNI,
- Zucker(LASTI))
- Data Analysis and Computing (Lazzarini)
- Advanced R&D and LIGO II (Shoemaker)
- CHANGE CONTROL BOARD/TECHNICAL REVIEW BOARD SESSION AS NEEDED
Special Items:
Special Announcements:
LSC Issues (Saulson)
no report
LIGO Laboratory Administration (Lindquist)
Status of LSC/MOU Research Updates and Program Reports (Petrac)
(LSC Research Updates through Aug. 2004, and Prog. Reports
through Feb. 2004)
Balearic:
- Attach. A / in LIGO review /
Lazzarini
GEO 600:
- Attach. B / in LIGO review /
Barish
- Attach. Z / in LIGO review /
Barish
Hobart&William Smith:
- Attach. A / in LIGO review /
Lazzarini
- Attach. B / in LIGO review /
Barish
- Attach. Z / to PI for
sign-off
National Astronomical Observatory-China (NAO-C):
- Attach. No. 1 / first draft
/ in NAO-C review
Groupe Virgo / Laboratoire de l'Accellarateur Lineaire,
Orsey (AV-LAL) / collaboration on detector modeling and 40 M program:
- Draft-MOU / in review
at AV-LAL
- Draft-Attach. No. 1 / first
year research plan / in LIGO review / Yamamoto and Weinstein
LIGO Outreach / collaboration between Hobart &
William Smith Colleges and Gladstone High School :
- Draft-MOU / in LIGO review /
Raab
LIGO Weekly Site Telecon (Lindquist)
A site teleconference was scheduled Thursday, June 10,
2004. The following issues were among those discussed:
- Procedure Manual (action
120): Ed Jasnow reports that he finally has all of the materials in
electronic form. It might be possible to send out a .pdf file this
afternoon.
- Budgetary Status:
Florence has begun the process of forecasting to the end of the year
Different approaches yeisl carry-forward funds between $2.5 million and
nothing. The process will continue.
- Hanford Inventory:
scheduled for next Wednesday and Thursday. A configuration management
audit will also be conducted (a working meeting to discuss current
procedures and deficiencies).
- Visitors:
Livingston to provide a list of students who are not visiting under the
SURF program so that Cindy can make sure that all are covered under Caltech's
processes.
The list of current actions revised to reflect the status of
open actions assigned through the last update (March 4, 2004) may be found at ACTION
LIST.
PROPERTY
MANAGEMENT (Chargois)
From:
Ed Chargois <chargois_e@ligo.caltech.edu>
- Provided assistance to the
Detector Group (J. Romie) with packing and shipping of LASTI hardware to
MIT (Ken Mason). Fed-Ex tracking number 6408 4948 0424.
Account Number P207761
- Provided assistance to the
Detector Group (H. Armandula) with the preparation of US Customs
Documentation, packing, and shipping of twelve (12) Sapphire Optics
to LMA-VIRGO (J M Mackowski), Lyon, France. Fed-Ex tracking
number 6408 4948 0354, Account Number P204296.
- Provided assistance to the
General Computing Group (M. Pedraza) with packing and shipping of five (5)
Disc Drives for repair to MAXTOR, Coppell TX. Fed-Ex tracking number
6408 4948 0424, Account Number 204261.
- Assisting Caltech's
Property Management Branch with the on Campus Inventory of PMA's
Government Property.
DOCUMENT CONTROL CENTER
(Turner, Mak)
>From:
Linda Turner - turner@ligo.caltech.edu>
Web pages for the DCC give simple
how-to's for document numbering, easy access to the latest on-line documents,
and search capabilities for the DCC database. Take a look.
. .
ACCOMPLISHMENTS
No report (LSC meeting and
vacation).
> From: Cleveland Mak
<mak_c@ligo.caltech.edu>
ACTIVITY
- No report.
Press here to access the DOCUMENT CONTROL CENTER WEB PAGE.
COST
SCHEDULE CONTROL SYSTEMS (Cunningham, Brambila, Kaufman, Salone)
From:
Esther Cunningham <esther@ligo.caltech.edu>
Press here for ACCOUNTS PAYABLE
HISTORY DATA.
From:
"Brambila, Ruth" <Ruth.Brambila@caltech.edu>
- Working on the five new
change orders to Triad.
- Issued one time standard
purchase orders for LIGO as submitted to various vendors.
- Cancelled the one time
standard purchase to Waveprecision shipping to France and re-issued it on
the LIGO subcontract to ship to Caltech. The vendor notified us it
was not in their best interests to ship the product directly to France.
Therefore, this order will now ship to the campus and then be exported to
France for mirror polishing.
- Working on the new
subcontract to LSU for the telephone service. Awaiting for a justification
on this new order.
- Placed and reconciled pcard
orders for delivery to the Campus. Followed up on back-ordered items and
pending credits for returned items on my credit card. Inquired about short
shipments received at LHO. Following up on obtaining the lead times for
back-ordered items. Modified pcard orders as requested. Preparing my
invoices on the pcard to begin reconciliation of pcard transactions.
Coordinated return authorizations on pcard shipments sent back for credit.
- Followed up on back-ordered
items placed on purchase orders.
- Updated the Access Database
for Procurement Services with the current information on all the LIGO
subcontracts. It now includes the contact person with title and phone
number, company address, telephone number. Updated the Excel spreadsheet
for the LIGO subcontracts.
From: Gina Salone <gsalone@ligo.caltech.edu>
- Updating contracts period
of performance.
- Working with Northrop
Grumman to correct a second Invoice.
- Set up a new contract for
LSU.
- Setting up payment request
and continuing to work with administrative staff to manage and maintain a
proper workflow.
From: Florence Kaufman <fkaufman@ligo.caltech.edu>
- Alerted Sponsored Research
Department that allocation of the second installment of the FY04 Award was
short by $156K, error has now been corrected.
- Set-up preliminary account
structure for the Outreach Award.
- Submitted Cost Transfer for
Facilities/Shop Charge that was made to transfer Facilities/Shop charges
from Riccardo's non-fabrication account to the fabrication account.
- Prepared chart comparing
labor costs to date with labor costs for the same period in the prior
year.
- Alerted Daniel Sigg that
the account for the Servo Control System at Hanford (2.8.15) appeared to
be over-spent. This was caused by a p-card charge being
mis-allocated to this account instead of to the 3.8.15 account. Cost
Transfer will be submitted to correct the error.
- Closed Atomic Clocks
fabrication accounts per Dennis Coyne's request.
- Notified Esther Cunningham
and Ruth Brambila that payment to CSIRO was misapplied to the
Subcontracts->25K expenditure type. Correction has now been made.
- Prepared an analysis of
projected expenditures for remaining period of the fiscal year based on
expenditures in the prior fiscal year.
- An updated list of account
numbers has been posted on the LIGO Internal Bulletin Board.
Financial reports can be found at: http://docuserv.ligo.caltech.edu/~fireport.
SUBCONTRACTS
MANAGEMENT (Petrac, Jasnow)
From: irena@ligo.caltech.edu (Irena Petrac)
- MIT: Change Order
No. 24, allocating the last FY 2004 budget increment, was released for
processing..
From: Ed Jasnow <jasnow@ligo.caltech.edu>
- A modification is being
prepared to the contract with ASI for the Advanced LIGO seismic isolation
system. This modification will incorporate the changes to the design
requirements, as well as the removal of the seismic isolation components
for the HAM chamber.
- A preliminary search has
begun for architecture/engineering firms who may be eligible for
consideration for the new outreach building at LLO. Emphasis at this
time is on firms in the Baton Rouge area.
SUPPORT (Baldon, Lloyd)
>Irene Baldon
- Worked on getting caught-up
on extensive e-mails and phone messages from vacation..
>Dorothy Lloyd
- [Note: I was absent for
report week ending June 3, however, I'd like to mention here that I
provided Ruth with the FY2003 "spending" information on all of
LIGO's subcontracts for the DCAA auditors.]
- Reviewed and recorded
payments processed by Esther May 10-28. Processed the usual invoices for payment
and tracked and followed up on invoice problems.
- Continue to monitor
contract and blanket order encumbrance and notify task managers when
supplements are needed.
- Jim continued with data
entry in the LIGO database and helping out in the DCC.
ADVANCED LIGO (Cost Schedule Control Systems) T. Frey
From: Thomas Frey
<tfrey@ligo.caltech.edu>
No report this week.
For list of documents that are being used to develop Adv. LIGO Cost and
Schedule, see http://www.ligo.caltech.edu/~tfrey/Cost_MTG_082002/
Project Web Site for posting schedule and progress related data continues
to be updated with the latest and greatest.
·
See http://www.ligo.caltech.edu/~tfrey/index.html
Reports
(Lindquist)
Operations Annual Report--the
Annual Report for Operations is due at the end of June. I have prepared
and distributed an outline and assignments, and have requested contributions by
Friday, June 18, 2004.
Change
Control/Contingency (Lindquist)
Ther are no open change
requests.
Human
Resources (Akutagawa)
From: Cindy Akutagawa
<cindy@ligo.caltech.edu>
- Various personnel/payroll
/HR related work.
Quality/Safety (Tyler)
>From: Bill Tyler
<tyler@ligo.caltech.edu>
Not much to report this time, just preps for next weeks LLO audit and the Surf student orientation..
.
LIGO Hanford Observatory (LHO) and Interferometer Operations (Raab)
Summary of Commissioning
Activities at LIGO Hanford Observatory (compiled by M. Landry)
4K IFO
The effect of injecting noise on the PZT steering mirror that points into the
OMC was studied.
In a separate study, it was shown that the small
bore in the OMC does not appear to be responsible for acoustic coupling.
An H1 modal reconstruction
of the dark fringe, decomposing the interference pattern into transverse modes,
was performed.
The beam centering servo in operation on the 4k sees evidence of alignment shift
during power up.
Raising the laser chiller temp strangely increased
the laser power output.
2K IFO
Problems were noted on several occasions with the digital controls, namely, switches
that misbehaved. Run/acquire switches are suspected in causing a variable
offset
in QPDY. Dewhites or run/acquire digital switches were suggested to be
malfunctioning.
H2 high-frequency noise was mysteriously
high early in the week. Furthermore,
ADC
noise is evident in ASPD2. Later the high frequency noise was
found
to be due to the ISS (read the summary status).
A laundry list
of things to do on H2 was posted.
DAQ
The H2 MY DSC system showed some instability.
Ongoing work was summarized.
Hanford1's boot disk failed,
later recovered
( recovery
II)).
Aside
More meteorological intrigues: another thunderstorm
took down networks and computers (see summary),
and evidence of a bright meteor was
searched for in PEM data but not found.
LIGO Livingston Observatory (LLO) and Interferometer Operations (Zucker)
Commissioning:
Joe Hanson, Oddvar Spjeld, Tom Evans, and Valery Frolov raised the IOT1 table
and lowered refl and trans periscope mirrors so that table could be moved
closer to HAM1 chamber over the HEPI actuators. Andri and I then locked the
Mode Cleaner and aligned the refl and trans optical train and the input beam.
Rai Weiss is working on RGAs, refitting them with lower-noise preamplifiers,
and fixed the MC servo board.
ETMX HEPI: With all position loops closed, the transfer functions from
ground noise to the support platform were measured in the X and Y directions.
An instability was observed when making the Z direction measurement. This has
since been tracked down to a change in the HEPI dynamics. The cause for the
change is still being investigated. One of the control loops was revised and
the Z-direction ground-to-platform transfer function is now being taken.
ETMY HEPI: The electronics and software were tested and a few minor problems
resolved. Another servo-valve was found to have ~1/2 the authority of the
others. It was replaced and the new one seems fine. The reason for the poor
performance of this servo-valve (as well as one found at the X-end station)
have yet to be determined. Transfer functions of the actuators to sensors (8 x
16 transfer function matrix) is being taken now. This effort was interrupted by
some timing skew problem, some processor hangup problems and a data drop out
problem on the reflected memory network. At the moment all seem to be fixed.
CORNER HEPI: Assembly and installation proceeds briskly. Leak testing is now
nearly complete from the pump station headers up to the bypass valves on every
pier. In excess of 1200 welds were made by the Excel crew as well as numerous
o-ring seal fittings. Only one pin hole leak has been found on a header that
was constructed by an outside vendor.
About 2 days were lost in BSC installation due to a crane controls failure
which has since been repaired. 3 of 12 BSC pier installations have been
completed.
All HAM HEPI mechanical systems have been installed, with the exception of
bolting the actuators on HAM3; We need to re-align the platform first and need
to formalize and document the alignment procedure developed at LASTI before
proceeding. Projected completion of all mechanical assembly is 6/18.
Electronics installation is also proceeding well. At least one HEPI corner
station system should be operational by 6/18.
Rich Riesen:
Safety Procedures Manual(s) Binders are now located in the control room,
Bonnie's office, and my office. With these manuals (in the control room only),
there is an ANSI Z-136.1-2000 (safe use of Lasers) manual and a copy of the
Laser Safety Plan LIGO M040112-07-M. There is also a Laser Safety Plan binder
in the HPLF.
New Laser Personnel sheets have been posted outside the change room in the
corner station, outside the entrance to the HPTF, and in the change rooms at
the ends.
A new Authorized Machine Shop Personnel sheet has been made itemizing the
machine shop's equipment and is the same format as the Laser Personnel sheet.
The sheet is posted outside the machine shop in the shipping/receiving
area. 2 new books have been added to the machine shop: Machine Shop
Handbook and Machine shop Training course (2 volumes). These books are
very useful for referencing: drill size, lathe speed, types of cutting blades,
etc. These books are on the shelf next to the phone.
3 new first aid stations have been added to the site. There's 1 at each end
station located in the change rooms, and 1 in the staging building's build-up
area on the south wall between the man door and the window to the lab area.
Stations include a first aid kit, CPR mouthpieces, a CPR/AED/first aid skills
card, (condensed "how to").
Our new AED (Automated External Defibrillator) is in its cabinet mounted on the
north wall outside the control room in the hall way.
This is the same AED we were trained to use.
Revised and updated Visitor sign-in sheets, laser access level sheets, training
sheets & material, eye exam forms.
A shipment of 3 crates were shipped to Ken Mason at MIT. 6 Geophones plus optic
alignment equipment.
Found no safety concerns during my weekly site tour.
Working with Ed Chargois on property matters.
In communication with Bill Tyler concerning the up coming LLO safety audit,
also working on same.
Igor Yakushin:
LDAS admin:
1) Installed LDR and LDRdataFindServer on ldas-gridmon.
2) Installed LSC DataGrid Client on ldas-grid.
3) Two failed T3 disks (u1d6@t3-10 and u1d4@t3-14) have been replaced. Got two
Fujitsu drives from SUN.
4) Prepared LDAS Power Requirements Spreadsheet per Albert's request.
5) Learning Python.
6) Published SG13 LIGO-TAMA MDC frames to LDR per Patrick's request.
Data analysis:
1) Attended LSC meeting in Boston.
2) Trying to run waveburst on S3 playground.
Ash Khan:
The following is my weekly progress report;
1) Implemented EPICS interface to the dual slider state code. The software simultaneously
controls the two PZT mirrors and helps positioning the beam into Mode Cleaner.
2) Implementing the dtt tools on linux platform as requested by Brian.
Chethan, CDS:
Fixed a problem with the End Y station 5579 network. Replaced a fiber.
Added a revised version of the watchdogs which subtracts the mean. A detailed
elog entry will be done later.
Working on the SEI STAT screen generation code.
I have rough draft of the disk space requirement on the frame builders. Will post
it soon after I recheck it.
Doug Lormand:
I have received the repaired lasers for the photon calibrators this week. I
tested the polarizations of each laser and found them to be in specification.
I'm moving forward with the final assembly of the photon calibrators. I hope to
have both boxes finished by early next week, and I hope to have them mounted
and aligned by the end of next week.
Tom Evans:
We are preparing to clean some parts in the bake oven. Since no loads have been
run through the oven for a while, we are currently running the empty oven
through a heat cycle. This will ensure the oven is clean, and will also allow
us to get a current RGA baseline scan of the empty oven. If no problems
develop, we hope to finish the cleaning cycle by next Monday and finish the
first load by next Friday.
Ken Franzen:
1) Processed the software injected AS_Q and auxiliary channel data from
the S2 playground (>65 for each interferometer) using DMTGen and
subsequently WaveMon. The purpose of this study is to determine the probability
of accidental dismissal of gravitational wave bursts using veto triggers
produced by the WaveMon algorithm set at different thresholds.
The results were presented during the glitch teleconference June 10. Please
find details at:
http://www.ligo-la.caltech.edu/~franzen/restricted/inject3.html
2) Participated in the installation of the 100 W laser, which has been returned
from the manufacturer after some minor modifications.
Oddvar Spjeld:
Completed
- update of the PDM Server model/drawing vault completed
- the server has been shipped to Caltech where it will reside
- HEPI Assembly Drawings officially released, DCN filed
- received the new HEPI Circuit Box mount plates on Wed 6/9
- completed assembly of the last two HEPI Actuator Housings for BSC # 2
Ongoing
- complete assembly of the last(!!!) four HEPI Actuator Housings for BSC # 3
- update drawing package for the HEPI Actuator to reflect as-built
- complete revision of the HEPI Assembly and Installation Procedure
Detector/Technical Support (Coyne)
CDS
see also the CDS weekly meeting minutes in the commissioning archives:
CDS Software
no report
CDS Hardware
no report
PSL
PeterKing
The beam pointing after a single-pass of the power amplifier
was monitored. Almost all the drift was in the horizontal direction and
seemed to coincide with a fall in the output power of the laser.
Re-alignment back to the fiducial point brought the power of the laser back up
but did not return it to its previous value. Monitoring of the NPRO beam
pointing was not possible as there was no convenient beam sample to use.
The transmission through the first turning mirror was not detector with an IR viewer.
OMC
PeterKing
Quotations were solicited for fabrication
of the OMC spacer. The PZTs used in the current OMC are vacuum compatible
according to the manufacturer. Quotations have been received from coating
vendors for the optics.
TCS
Mike Smith
Mc Master hardware order was delayed until this week, for
arrival the week of June 14. Completed the assembly drawings. Wrote a DCN and
released the REV A drawing package to the DCC. The drawing package was given to
Phil W. to place on the AOS website. I also placed the drawing package on the
~Smith/AOS/TCS public directory. Completed a revision of the installation and
alignment procedures for the 2K and 4K TCS CO2 Laser Projection System:
T040014-01. Generated two different Parts Lists to reflect the as-installed LHO
4K TCS, and a new parts list for the upgraded TCS Laser Projection System that
will be installed at LHO and LLO in June 2004. Made travel plans to be at LLO
the weeks of June 13, and June 27 to assist in the assembly and installation of
the TCS.
Baffles
Ken Mailand
I've sent the Baffle drawings to the DCC.
Optical Contamination Cavities
Lee Cardenas, Liyuan Zhang
OTF Lab. (W. Bridge)
The test for contamination of
(21) pieces of the twisted, shielded, teflon cables are completed.
We are going to take these cables since the report shows that they are
clean.
We have some new samples to check the epoxy contamination. These samples
will go in this week.
Absorption Test Measurement prototype in progress
The scanning for absorption of the15 cm dia. sapphire substrate is
completed.
scanning at different depths Z= 10, 15, 20, 25, 30, 35 ,40, 45 mm and so
on.
Data it is been treated, waiting on results.
The 30 watt laser enclosure.
The modification of the rods needed are completed and installed.
All the plates have been cut to size and installation is in progress
Scatterometer system in standby
OTF Lab at Lauritsen ROOM 38 NO
CHANGE.
Cavity #3
The cavity is locked and we are taking ring down and beat frequency
measurements.
Cavity #2 Test cavity optical set up is still in progress.
PSL
New10 watt laser alignment is in progress.
40 Meter Interferometer (Weinstein)
- Mach-Zehnder:
- We continue to
prepare a Mach-Zehnder (MZ) interferometer on the PSL table to apply 33
MHz and 166 MHz sidebands in parallel, rather than in series. The MZ draft design
is being further developed by Osamu.
- Steve is gluing
together the PZT, mirror, and mount for the Mach-Zehnder actuation. A jig
for carefully gluing the tiny mirror onto the PZT is being made in the
shop.
- Steve has assembled
all the optics, mounts, etc for the M-Z. Everything is about ready for
installation.
- Jay and Ben have
prepared the necessary rewiring of the IO rack to monitor and control the
M-Z RFPD (a regular LSC RFPD) and the M-Z servo board / PZT driver (a
slightly modified PMC servo board). We have a spare channel on the LSC
RFPD Interface board in the IO rack, and a modified PMC board is being
prepared in the CDS shop. We thus hope to have all the electronics ready
next week.
- Osamu has calculated
the beam size through the M-Z; it is less than 0.4 mm at all the EOM
apertures. He is now calculating the mode matching into the mode cleaner,
but we expect little change from what we had before, because all the path
lengths are the same. We will optimize the mode cleaner visibility by
moving the 2nd MM lens on a translation stage.
- Osamu and AJW have
calculated the expected visibility of the M-Z due to imperfectly-matched
beam splitters; it should be better than 98% from that effect, for 50%
BS's with 5% tolerance.
- We will instrument a
new photodiode in the M-Z to monitor the input light from the PMC, and a
new video camera at the periscope to look at the light transmitted from
the M-Z (there is already a photodiode there).
- In preparation for
installation of the M-Z, Osamu has taken baseline frequency noise
spectra, both in the FSS loop and out-of-loop with the mode cleaner, and
also intensity noise spectra, before and after the EOMs. Details in the
PSL section below.
- We plan to organize a
telecon in the next week to review the requirements and design of the MZ
interferometer. All interested LIGO and AdvLIGO people are encouraged to
contact ajw@ligo.caltech.edu to attend.
- PSL:
- Osamu continues to
work on the PSL FSS board to improve its UGF and stability.
- Osamu has taken
baseline frequency noise spectra, both in the FSS loop and out-of-loop
with the mode cleaner. The out-of-loop spectrum looks just about as good
as it did last year. The in-loop spectrum has revealed problems since the
replacement NPRO went in last March. Osamu and Ben have been fixing them
as they are discovered. The most recent problems seem to be related to an
AD829 opamp in the fast PC loop of the FSS, which is getting fried. Osamu
has replaced it twice. He and Ben now plan to protect it with a diode
clamp, as is being done at LHO. They also plan to make another mod per
the work done at LHO: add capacitors to AC couple all the gain stages,
not just the first gain stage, to eliminate a DC offset that grows with
time. They hope to recover a UGF of ~ 300 kHz after these mods.
- Still, there is a
dynamic range problem in the fast loop which could be cured by replacing
some opamps with faster ones (also part of the LHO mods). Osamu and Ben
plan to do that as well.
- And still, there is
some phase delay limiting the gain at the highest frequencies; Osamu
suspects some phase delay in the PZT actuator of the replacement NPRO.
- Osamu has also taken
intensity noise spectra, before and after the EOMs, with ISS turned off
(see below). The intensity noise is everywhere better than LIGO spec. It
agrees with spectra taken in Nov 2002, above 7 Hz. Below 7 Hz it is ~ 3x
- 8x worse. This could be due either to the new NPRO, or to the mods to
the current shunt made a few weeks ago by Flavio and Peter. Still, it
should be tolerable (especially with ISS).
- The intensity noise
after the three EOMs is worse still, by 3x - 10x, below 10 Hz. Still, it
should be tolerable (especially with ISS).
- The ISS has been
turned off due to a large offset problem that developed 2 weeks ago. We
await word from Flavio on how to fix it. The largish fluctuations in AMPMON
that we were accustomed to before the ISS are now back. AMPMON is still
down to 10.4 W.
- LSC:
- Rolf and Alex
installed the new LSC cpu and software last week, but the cpu hung after
a while. Since it worked at Wilson House, the crate and/or cables were
suspect. A new vme crate was brought over and installed, and the system
seemed to work... for a few hours. Then everything died, and the crate
power supply seems to have failed. Under investigation by Rolf, Ben, and
Rob.
- Rob has completed a
first draft LSC InputMatrix code; it was running and doing what it was
supposed to do (before the LSC cpu / crate problems started). Rob now
knows how to compile, build, link, load, and debug the lsc front end
code. He's now working on code for autolocking the FPMI.
- The plan developed by
Seiji and Osamu to lock the MICH using dither locking requires the RF
sidebands to be turned down very low. Now that we have a M-Z, we use
those sidebands to lock it. It is not clear whether we can find a
modulation depth which allows us to lock the M-Z without messing up the
MICH dither lock very much.
- The LSC aux crate 2
has not been set up yet, but it will be installed and commissioned soon.
- Ben will go around
and cut unused wires on all the Pentek cables to stop propagation of 1
MHz clock signals.
- Oplevs:
- Fumiko now
understands the relationship between the gain of the oplev servo and the
Q of the pendulum TF. The presence of the OSEM damping in addition to the
oplev servo means that Q doesn't go like 1/gain.
- There is no evidence
of saturation in the oplev servo, even at high gain (it starts to
saturate at gain ~ 300).
- Fumiko will continue
to develop the oplev filter design.
- She will then go on
to implement the oplev servos for all core optics, optimize their gains,
and study the arm lock acquisition time as a function of oplev servo
gain.
- South Annex bake ovens (Bob
Taylor):
- Bob continues to do
bake loads for Janeen, Ken Mason, and others for the LASTI triple. It's
mostly done!
- Bob continues to
clean parts and do bake jobs for Larry Jones.
- Bob is writing a
cleaning procedure for HML Mag wire.
- Bob continues to
build up the new ultra-clean bake oven.
- Lab infrastructure:
- Ben Olsen documented
his work diagnosing problems with the STACIS system, before leaving for
the summer. It looks like at least 3, maybe more, of the isolators need
to go back to TMC for repair.
- The particle counter stopped working. Steve struggled with it, cycled the power several times, and it came back up.
Thermal Noise Interferometer (Libbrecht)
In the past two weeks, we have been looking at the BENCH models of noise in
advanced LIGO, taking into account the results of the direct measurements at
the TNI.
Attached is a plot of the expected AdLIGO thermal noise curve, based on our
measurements of both coating thermal noise and Braginsky noise in Sapphire.
This is similar to the plot we posted last week, except that this plot includes
a breakdown of the different thermal noise sources in Sapphire. In the figure,
the curve labeled "A" is the quantum noise, radiation pressure plus
shot noise, for an interferometer with Sapphire mirrors using the BENCH tuning
parameters. The "B" curve is the Braginsky noise. "C" shows
coating thermal noise, assuming a silica-tantala coating on a Sapphire
substrate. "D" is the bulk thermal noise in a Sapphire mirror that
arises from structural damping, where we use the Q value listed in BENCH.
"E" is the sum of all three thermal noise mechanisms in Sapphire, and
"F" is the equivalent thermal noise sum for fused-silica mirrors. The
thermal noise in fused-silica mirrors is dominated by structural-damping
losses, and for this calculation we have again used the BENCH value for the Q
of a fused-silica mirror.
With the rather large spot sizes expected to be used in Advanced LIGO, coating
thermal noise lies well below bulk thermal noise in a fused-silica optic,
whereas in a Sapphire mirror, coating thermal noise dominates above about 200
Hz. There is clearly room for improvement here, if lower-loss coatings could be
developed. In fact, such an effort is already well underway, and Gregg Harry
has told us that the coating collaboration has reported a possible improvement
by a factor of two in the loss angle, which translates into an improvement in
the coating thermal noise by a factor of root-2. If this improvement is
reproducible, it would bring the coating thermal noise almost down to the same
level as the bulk (structural) thermal noise.
Increasing the spot size would also lead to in improvement in the thermal
noise, of course. Braginsky noise scales faster with spot size than coating
thermal noise, which in turn scales faster than bulk thermal noise. Therefor a
modest increase in spot size would lower all three curves and bring them closer
together.
One last thing to note is the level of Quantum noise. This curve shows the
quantum noise for an interferometer tuned to BENCH's parameters. The quantum
noise for this configuration lies well below the thermal noise over more than a
decade of frequency, then becomes the dominant noise source above 1 kHz. If the
interferometer could be re-tuned to reduce this high-frequency quantum noise,
even at the expense of the quantum noise around 100 Hz, substantial
improvements in the noise floor could be obtained, and improvements in the
coating would be used to better advantage.
The initial purpose of the TNI was to compare, by direct measurement, the
relative merits of sapphire and fused-silica optics, and to try and predict
which material would be a better choice for Advanced LIGO. This analysis
completes this first stage of the experiment. The next step is to measure the
thermal noise in advanced coatings, such as the improved coatings mentioned
above, and to study non-Gaussian noise in mirrors and suspensions.
LASTI (Ottaway)
no report
Data
Analysis and Computing (Lazzarini)
Simulation and Modeling
(Bhawal)
Weekly Physics Meeting
------------------------
Sany Yoshida from Southern Louisianna University presented results from his new
measurements of the coupling of translational degree of freedom from seismic
noise to angular degrees of freedom at suspension point through stack. Results
can be viewed at
http://www.ligo.caltech.edu/~e2e/pdfs/Sany/
Beam-splitter (BS) curvature problem
--------------------------------------------
(Hiro) FFT Code:
The FFT program does not support the BS curvature explicitly. Based on
the recent study, the BS curvature seems to play an important role, the code
was modified to explicitly support the BS curvature, just as other mirrors.
During this process, several interesting features, like the effect of finite
thickness and 45 degree tilt of the beam splitter on the dark port output, were
noticed which could be related to the observation of the large imbalance of the
sideband powers in the dark port output, while total powers in the Michelson
cavity do not indicate such imbalance.
(Biplab) E2E Code:
Changes have been made in e2e code to accommodate perturbation
calculation for beam-mismatch and the consequent astigmatism that may originate
from BS curvature. After validation CVS will be updated.
Similar changes have been made for reflection from the curved mirror of
triangular cavities. In a well-designed large cavity in which angle of
incidence is very small, the effect of astigmatism may be negligible but for
Output Mode-cleaner that may not be the case.
Mode-Cleaner Length Sensing and Control
----------------------------------------------
Nafis Jamal, a student of Sany Yoshida of Sothern Louisianna University has
started studying length sensing and control of the mode cleaner using e2e.
Biplab supplied him a standard box for studying optical properties of mode
cleaner and interacted with him on use and physics of triangular cavity module.
Alfi
-----------
(Bruce)
Last Week:
Alfi 5 Software Development:
- Completed problem helping modeller
in situations where Alfi
has implicitly removed a
connection. (PR 444)
- Checked and cleaned up a variety
of PRs which were small
problems and/or possibly
fixed along with other more
serious issues over the
past months. Including port
repositions in the
external view (PR 391), closing of
splash window (PR 403),
disallowing removal of inherited
ports (PR 353), port
problems when located near end of
queue (PR 361), and an
old junction code problem (PR 368).
This Week:
Alfi 5 Software Development:
- Old box files now trigger a resave
option on quit to
update them.
- Upgraded an Alfi preference file
to make it safer
regarding possible
changes in the E2E_PATH between sessions.
- Adding a new dialog to make the
changing of the E2E_PATH
variable more user
friendly and less confusing in terms
of the end results (PR
455).
(Melody)
Working on several problem reports (PRs 439, 437, and 421).
Looking at JavaHelp as a possible addition to ALFI's online help.
Will be testing JGO 5.0.
LIGO Data Analysis System
Software Systems (Blackburn)
The shared object library for discovering frame data external to LDAS systems
made it out the door this week (at least the first version). LSC teams
interested in using this library have been notified of the package distribution
and locations for solaris, linux binaries, as well as the source code
distribution. The documentation needs more work, but a set of simple text files
describing the use of the distribution has been made available. Web pages will
show up soon. The first distribution did have an unnecessary dependency on the
openSSL library which will be removed in a subsequent release. These
distributions are now being built automatically each night on the DLAS-DEV
system.
A new implementation of the memory usage throttle for the dataConditionAPI has
been written and tested. This second attempt to address the issue has been
successful and now in CVS.
Work began on PR 2526 to solve a diskCacheAPI message passing issue between the
C++ and Tcl layers.
A new Swig interface will be added to the diskCacheAPI to allow the Tcl layer
to respond efficiently to requests to the controlMonitorAPI in an effort to
graph the time ranges for which frames are known about under an LDAS system.
Ran through the system and integration test suite and updated the results on
the web site.
Added a test for maximum rows inserted per second of analyzed data. It was able
to hit the 1000 rows/sec limit by using a modified ilwd file with a
putStandAlone job.
The weekend run of LDAS hit a new all time high job rate. We have now seen
sustainable 2650 jobs per hour for more than two days without a single job
failure. This is about 10% better than any earlier records and is attributed to
more efficient Tcl code in the diskCacheAPI.
Hardware Systems (Anderson)
Caltech
-----------
(Hari Pulapaka)
* Getting familiar with the lsync (diskcache) project. Installed it and
tested it on linux box. Getting familiar with lsync.tcl code.
* Upgraded the rls server on ldas-cit.
* Modified the LSCDatafindServer setup on ldas-gridmon to make it
recover from crashes.
* Modified the setup on ldas-gridmon to enable Keith Thorne to run his
Matlab run-time library and BNETG filter files.
(Dan Kozak)
* Continued the transfer of files from HPSS to SAM-QFS. Also continuted
deleting files in HPSS after confirmation that they were successfully
transferred.
* Got /archive/dmt set up to archive to tape and confirmed that all
files
copied so far have been written to tape.
* Imported post-S3 tapes from LLO/LHO. LLO data has been FrCheck'd,
LHO data is being checked now.
* Got QFS license for LHO:fb0 (note to those who know/care: Harold
Hudson
is back at work and this process only took a few hours).
(Al Wilson)
* Replaced more drives in datacache7, 8,4.
* Replaced motherboard in a node system. testing before putting online
* setup BB to monitor soft failures on memory for sun systems
* configured tamdom 3 to mirror unit 5
MIT
------
(Keith Bayer)
* gc: helping with LSC conference
* ldas: building condor and associated utilities on ldas-jobs /
ldas-pcdev1
Livingston
---------------
(Igor Yakushin)
* Installed LDR and LDRdataFindServer on ldas-gridmon.
* Installed LSC DataGrid Client on ldas-grid.
* Two failed T3 disks (u1d6@t3-10 and u1d4@t3-14) have been replaced.
Got two Fujitsu drives from SUN.
* Prepared LDAS Power Requirements Spreadsheet per Albert's request.
* Learning Python.
* Published SG13 LIGO-TAMA MDC frames to LDR per Patrick's request.
Hanford
-------
(Greg Mendell)
* There is nothing significant to report on my part for the last week,
as I was
at the LSC meeting.
(Ben Johnson)
* Upgraded RLS server on gateway and ldas-gridmon to v2.1.5
* Added 20 more tapes to the L700 library. We now have approximately 40
blank tapes available.
* Setup QFS filesystem on fb0. Due to the 1TB device limitation in
Solaris, the 3510 was partitioned in a non-optimal way, ultimately
giving a 1.0TB QFS filesystem.
* Continuing work on data corruption report. Specifically with
corrections provided by feedback from John Zweizig.
Data Analysis Activities (Lazzarini)
Creighton:
This week I vetted an analysis of biases in the stochastic background
estimator, and also tracked down some ``interesting'' behaviour in LAL pulsar
signal simulations (that turned out to be due to an approximation we were
using, and are observationally insignificant).
Mendell:
Presented the first preliminary upper limits from the StackSlide code using the
S2 data and Monte Carlo injections at the June 5-6, 2004 LSC meeting in Boston;
see DCC document LIGO-G040256-00-W.
Shawhan:
* Attended the LSC Meeting at Tufts, plus the face-to-face meeting of
the Burst Group on Monday.
* Working on planning and organizational issues for the burst group.
* Helped Chethan look into a problem with ndsproxy at LLO.
Sutton:
The LIGO-TAMA analysis was my main concern again this week. I prepared and
presented talks on the LIGO-TAMA analyses for the PAC meeting at Caltech and
the LSC meeting at Tufts. I've studied the first TAMA SG13 triggers, looking at
the network efficiency.
I also generated TFClusters 3x coincidence triggers and forwarded them to
Cadonati for R-Statistic processing.
Besides LIGO-TAMA, I'm working on a report about validation of the bursts
MDC frames, (which was my major focus last week), and we had our first
TFClusters code walk-through telecon today.
Sylvestre:
o Started some tests for the TFClusters review: white noise input,
determinism of the code, etc.
o Organized the code for the review.
Yakushin:
1) Attended LSC meeting in Boston.
2) Trying to run waveburst on S3 playground.
Lazzarini:
Working with Rai to revise a proposal to start looking at the all-sky SGWB map
problem in greater detail.
General Computing (Wallace)
MIT:
(Keith)
-Supported the LSC conference. Overall things went well. Wired network
connections proved to be an issue, something to address for future meetings.
Livingston:
(Shannon)
- Current bandwidth usage can be seen at
http://teche.ligo-la.caltech.edu/mrtg/LLO-Router/130.39.245.1_1.html
- Archived bandwidth usage can be seen at
http://teche.ligo-la.caltech.edu/mrtg/archive/
under the dated folder
for the week of interest.
- Most of this week has been spent installing some new backup software.
The tape library has been hooked up to a non-production Sun and the 30
day evaluation copy of the software has been installed. I am in the
process of testing the backup/restore process with the server and a
test client. So far it is going fairly well and I hope to have the
software fully tested and rolled out by early to mid next week. There
have been a couple of issues with the Solaris sst driver configuration,
but so far things seem to be working as expected. This should greatly
improve our backup situation at LLO since we have been backing up to a
RAID server since we outgrew our last solution. In addition, the
software I am testing has a client for nearly every platform imaginable
(Sun, Windows, Mac, *BSD, etc.) which will be more flexible than the
last solution. It is also cheaper. Assuming the testing goes well,
I
will have to order some tapes next week for the library.
Hanford:
(Christine)
- Network usage can be seen at
http://www.ligo-wa.caltech.edu/~christin/mrtg/
198.129.208.1_198.129.78.122.html
- Created lots of user accounts for SURF students and new LSC students.
- Working on some problems with Norton Antivirus. On one computer the
realtime scan wasn't catching an e-mail with the Netsky worm. The
protection level was upgraded to maximum, now the realtime scan catches
the worm but it quarantines the whole inbox. Two others had old
versions of the Symantec client software and although the logs showed
the virus definition files were being updated, the date and version
number displayed was not being changed.
- Contributed to some GC policy updates.
- Sent instructions to a traveler to setup e-mail with ssh.
- Replaced the hubs in the LVEA for the GC network.
- Replaced a GC hub in the LSB computer user room.
- Helped with planning of the CDS backbone upgrade from ATM to GigE.
- Some time spent on CDS software development.
- The usual user support.
CIT:
(Mike)
-Tried loading a high end workstation to setup as a visitor workstation, after
many attempts/configurations I have given up on loading this pc. This pc
definitely has a hardware issue. I do not have the parts to troubleshoot this
unit.
-Loaded a workstation for a visitor that came from Glasgow. GariLynn freed
up her workstation that was located in her office. This is a much better workstation
to use than what we have in stock for visitor workstations. This is needed for
this user to run solid works and other engineering software, in order for this
user to get his work done. I also upgraded the memory on this unit.
-I upgraded zonealarm firewall software to its current version on the NTSRV's.
Everything seemed to be working, but found out later on in the day that
the services were only working on the internal network. The outside world was
not able to access the web services. I had to un-install this software then
re-install to an earlier version of the zonealarm software.
This only affected the NTSRV's IIS, FlexLM, and web-base services. The stand
alone workstations such as pc's & laptops should not be affected by this
issue.
-Janeen Romie: I un-installed solid works, pdmworks and the toolbox due to
this software getting corrupted. I did a clean installation of solid works
and pdmworks plus installed all service packs.
-Currently loading another workstation that will be an additional solid works
workstation, and will be setup in the same location where our Glasgow
visitor is at.
-Installing more software on the vmware installations XP, win2000, and server
2000 that I have installed on my workstation. I have been running multiple
tests on these installations before I push out patches and enhanced security
changes to our user workstations; much more work is needed on these
installations.
-I finished up running a diagnostics on multiple hard disks for Stuart Anderson
and company I have sent out 5 more RMA's.
-Ran security OS/office updates on the following user workstation: Gina Salone,
Jim Covington and Dorothy Lloyd.
-Updated users software to Eudora 6.1 & Adobe 6.0 this week: Mike Smith, Jim
Covington, Dorothy Lloyd and Gina Salone.
-Other misc. onsite/phone user support.
(Lisa)
- Created a couple of new accounts.
- Spent a quite a bit of time looking into an e-mail error that Dennis Coyne
reported. I made some small tweaks to the mailserver configuration,
but I think part of the problem is that he is using a very old version of his
mail client.
- One of the ap-2000's had hardware failure. I RMA'd the defective part.
Mail Stats 6/3 - 6/9/04
Messages Accepted:
Spam Rejected:
Viruses Rejected:
False Positives:
Total Mail Thru:
(Veronica)
- LSC website: Last-minute updates to the June meeting website. Posting transparencies
from the meeting as they arrive. Looking into modifying the database that
drives the webpages for the meetings transparencies. Updates to other parts of the LSC
website (papers for reviews).
- LIGO website: A webpage for the highlights of the computer use policy.
Updates to Internal Bulletin Board, seminars, PAC meeting website.
- Project Science website: Troubleshooting of the database backend for the
registration for the upcoming workshop. Both the database and the front-end
html are now in place and running.
(Larry)
-Assisted the DCC with a number of items. Most were file fixes and a minor
issue with one of their workstations.
-Assisted Lisa with her continual (never-ending task) with the spam filtering.
Also, helped a few others with e-mail issues. All were configuration issues.
Along that same line all those using Eudora should be using version 5.x.
-Worked/working a number of documentation issues. Thanks to the LIGO sysadmin
group we have a few good additions being approved for the computer use policy.
There is a policy summary and update webpage being developed and should be
on-line next week. More detail on acceptable use is being worked on.
-Made a number of purchases. A couple for Mike to get some equipment back
up and running.
-Helped with a couple of minor PAC logistical issues.
-Worked a couple of printer issues. The new drivers on the print server had
to be modified in a couple of cases to accommodate printing on one of the
older printers. We discovered the BIOS on the older 4500 printers can not
be updated without purchasing a new chip for the unit (not worth the
cost). Also, the printserver appears to be having some h/w problems so a
new unit is being purchased.
-Worked and still working on a couple of E2E issues. We've been testing out
the h/w on the new application server. If all goes well the server should
be on-line by the first of next week and Virginio can start loading
applications.
-Had the sargas sandbox problem resolved. It was a memory h/w problem and
SUN did replace a number of boards. We will be running tests again on all
of the sandbox units in the near future.
-Adding user accounts and did do some more cleanup. We are working on removing
old accounts no-longer in use.
Advanced LIGO and Supporting R&D (Shoemaker)
Seismic Isolation
From: Larry Jones <ljones@ligo.caltech.edu>
Advanced LIGO Seismic Structure
SEI Structure:
The final Finite Element Models of Stages 1 and 2 are completed, and that
of Stage 0 is in process.
A detailed drawing tree for the BSC structure hardware has been prepared.
Pod drawings are in review.
The thermal straps for both actuator bobbins have been sized. Thermal
properties of the bobbin straps have been verified by COSMOS Works and
documented in ASI Report 20008562-101.
The Design Review meeting for the BSC structure will be held
Actuators:
The following materials were received, precleaned by Bob Taylor, and shipped
out for further processing by PSI (the actuator developer) and its vendor:
nickel plated magnets, nickel plated mag-iron pieces, silver plated fasteners,
and HML-insulated magnet wire. Precleaning the wire required unspooling onto a
collapsible reel, batch cleaning in toluene, and respooling onto cleaned spools
using a special fixture. Receipt of the following materials for precleaning is expected
soon: actuator bobbins and additional silver plated fasteners. These parts are
for making 2 prototype actuators of each size, large and small. One set of
prototypes will be shipped to LIGO and one set is retained by PSI for internal
testing. Some of the nickel plated magnets for the large actuator had been
damaged in a shipping incident prior to being plated; these will not be used in
the prototype for LIGO.
RGA scans of the candidate epoxy potting material were made at LHO and deemed
acceptable for material qualification. These test coupons will also be
subjected to optical cavity testing.
Actuator bobbin winding is scheduled to start 14 June.
Displacement Sensors:
Jay has ordered the BSC SEI sensors.
Test coupons of two epoxies used in the Displacement Sensors will be tested in
the optical cavity for confirmation of suitability.
Seismometers:
Requests were made of Quanterra, Streckeisen's
Galling/Dusting Test:
Nothing new.
Suspensions
From: Janeen Romie <romie_j@ligo.caltech.edu>
Mike Perreur-Lloyd from the
Talked with Justin about osem counts. I'll review his updated table and get
back with him.
Completed suspension Primavera updates and forwarded redlines to Thomas. He
worked with us on Tuesday to provide direction, which was very helpful.
Ian Wilmut sent me ETM blade drawings for quote. However, he'll have to make
slight changes before I can do that.
Attended the commissioning meeting on the output mode cleaner. Reviewed Gregg
Harry's electrostatic research plan.
MC to LASTI
The two transit cases reached MIT yesterday.
Created a preliminary installation document. Created a transfer document.
Forwarded both, along with many other related suspension documents to D.
Ottaway.
Bob's bake oven schedule is working. He/we have delivered associated hardware
for this work to LASTI.
From: ctorrie <ctorrie@ligo.caltech.edu>
I was on vacation last week, this report summarizes the report weeks beginning
the 19th May and 2nd June
1) MC for LASTI
Helena, Laurent and I finished assembling the MC in preparation for its
transfer to LASTI. This was fairly successful and in particular our inclusion
of oversized taped holes made assembly a lot easier. There were a couple of
instances where problems occurred although we believe these have now been
fixed.
We also took the opportunity to update the assembly procedure for the MC,
LIGO-E030158.
Last Wednesday the MC was shipped to MIT via ground transportation. It arrived
I believe on the 9th June.
We have also prepared several documents, most of which existed in some form or
another, for transfer with the MC to LASTI. These are summarized in a transfer
document.
2) Advanced LIGO Suspensions
Mike Perreur-Lloyd is visiting from
We met with Janeen and Thomas to update the Primivera for the last 2 months.
It is hoped that we will be able to go for quote this week for the cantilever
blades for the controls prototype quadruple pendulum. The blade committee has
been working hard to prepare the relevant information and I have been working
closely with RAL in preparing the detailed drawings.
Pre-stabilized Laser
From: Peter King <pking@ligo.caltech.edu>
AdvLIGO PSL
===========
Shally Saraf (Stanford) has started taking data in the
saturated amplifier noise experiment. All the various cavities that are
used for tidying up the beams and defining a beam waist and location have been locked.
Some initial problems with the photodetectors being used have been
sorted out.
Maik Frede (LZH) tried lengthening the 200-W laser resonator
length in an attempt to remove the mode-control apertures and obtained 190 W
with an M-squared of 1.2. Which represents a drop in output power and
degraded beam quality than that achieved previously. The resonator length
has been returned to its previous value. At present the output power is
197 W, compared to the 213 W achieved around the time of the March LSC Meeting.
The M-squared value was better
than 1.15. Next step will be to injection lock the high power stage.
I ordered a few GAP2000 photodiodes from Germanium Power
Devices (GPD) to test out another high power photodetector topology. With
a bit of luck it should be able to surpass the present current limit.
Core Optics
From: Helena Armandula <ahelena@ligo.caltech.edu>
Advanced LIGO Coating Development
LMA
A 3"dia. x 1" thick fused silica substrate coated with Formula 3 was
ready to be shipped to Glasgow for coating noise characterization.
The coating run for the thin substrate being coated with the same formula
failed. The chamber's target cooling system malfunctioned causing the target to
collapse.
So, a thin substrate and a sapphire substrate remained to be coated. The Ti
concentration on this coating formula was not as high as expected, even if the
concentration was higher than Formula 2. The absorption was improved and
measured ~0.3 ppm.
Auxiliary Optics
From: Michael Smith <smith@ligo.caltech.edu>
Met with Thomas Frey regarding progress reporting for the AOS Task. Phil
Willems and I assessed the percentage completion-to-date on the various AOS
tasks. Phil will report to T. Frey.
Other Laboratory R&D
From: Riccardo DeSalvo <desalvo@ligo.caltech.edu>
### DHS – The text of the weekly follows – please see www.ligo.caltech.edu/~desalvo/03-10-06weekly.doc
for a nice version with interesting figures.
---------------------
Nicole Virdone, senior from
Hareem
Maraging paper received by NIM, now to the referee.
Ref. P-040002-00-D
Can be found in
www.ligo.caltech.edu/~desalvo/a-maraging
Hysteresis paper.pdf
or in
www.ligo.caltech.edu/~desalvo/a-maraging
Hysteresis paper.doc
Virginio
Added few comments from the internal referee and submitting
the MGAS theory paper.
It can be found in
www.ligo.caltech.edu/~desalvo/P040004-00.pdf
Maddalena
In this week I have finished the mechanical improvement of
the MGAS spring and I started to take some Transfer Function measurements.The
new mechanical set up is constituited by a rebalanced system, a coaxial LVDT
and actuator system and a thermal and wind isolation box around the apparatus.
With the new apparatus the noises due to unbalance of the
system are practically disappeared.
I cannot record yet the performance obtained in 2001 on the
same spring. Infact I my measurement saturates at an attenuation of ~ 45 dB
instead of the ~ 55 dB recorded in 2001 (figure 3). This is due to the fact
that the attenuation in 2001 was measured by a system of accelerometers instead
of a system of LVDT. We will further boost the power of the shaker voice coil
at high friquency (over 1 Hz) and push down the noise floor of the sensor LVDT
(by reducing its dynamic range.
The measurement, though, will be limited by the mechanical structure and
substantial improvements may require large changes. The payload LVDT measures
the payload position with respect to a reference plate, which is also on the support
structure and is shaken by the reaction force of the excitation actuator. If there will be time and if we can
find accelerometers we will repeat this measurements with accelerometers.
With the new
set up we are able to reach lower resonant frequencies, obtaining for the
moment a resonant frequency of ~60mHz so far.
With Phil and Virginio’s help, we finally got the Lab View
program working, we can now acquire the data through the computer, and we will
take some long term measurement to study the filter behavior as a function of
the temperature by monitoring the temperature stabilization circuit while
heating the air inside the thermal box.
Barbara
In this
week we moved all the vacuum components down to OTF and are now preparing for
assembly. We successfully moved
the main vacuum pipe from the synchrotron to the OTF lab dropping it down the
elevator shaft.
Please
watch photo gallery at
www.ligo.caltech.edu/~desalvo/Pipe-to-WB-SB.ppt
We received
the LVDT and the control coils so we are now ready to assemble the seismic
attenuation of the experiment.
I also
calibrated the blades and we have made some modifications to the mechanics, and
we are now almost ready to mount the mechanics the cavity.
At the end
of the next week I think that the mechanics part of the apparatus may be ready.
In the meantime I’m finishing building the box for the circuit to control the
piezos.
Juri
I am
studying the optical properties of non aligned mexican hat cavities.
I found a
general first and second order solution to the perturbation problem for a
complex symmetric (non Hermitian) kernel using the known property of
bi-orthogonality between its eigenfunctions and the eigenfunctions of the
transposed (or adjoint) operator.
I used this
formalism to calculate the coupling between the fundamental and the first
higher order mode, induced by a symmetric misalignment of the cavity’s mirrors
for a Mexican Hat nearly flat and nearly concentric configurations.
Now I am
investigating some mathematical points related to this perturbation theory and
the limits of its validity.
I adopted a
new method for solving the integral equation for the eigenmodes of the cavity,
based on the Gaussian quadrature technique, because the basic trapezoidal rule
seems not enough precise (with a reasonable number of integration points) to
obtain the diffraction losses with a precision of 106 which is
required to calculate at which mirror diameter we can truncate the mexican hat
deposition profile. The results are very good with less computational power.
I wrote a
Mathematica notebook to compute
the electromagnetic field across the mirrors of the cavity where an initially
launched wave is reflected back and forth between the mirrors (aigned or
misaligned) until a steady-staty field distribution is obtained (this technique
was adopted by Fox and Li to study the resonant modes in a Maser
Interferometer). This is a simulation of what really happens in a F-P cavity
and it is useful in order to check the results from perturbation theory and to
make a comparison with the experimental results from our Mexican-Hat cavity.
For additional information about this report, contact whitcomb_s@ligo.caltech.edu