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The LIGO Executive Committee
Agenda for Monday April 3, 2000 will be:
(Meeting time: 10:30 am Pacific Time)
Open meeting 10:30 - 11:30
Special Items: Operations Budgets Review
No report this week.
WBS 1.2 LIGO Operations--Administration
The primary agenda item concerned actual costs through February compared with the budgets. M. Coles and F. Raab have been requested to review their budgets to determine if "mid-course corrections" are needed. Cost reports will again be reviewed April 13 using end of March data.
The monthly report can be found on the network in .pdf format.
From: Ed Chargois <chargois_e@ligo.caltech.edu>
Assisted the Detector Group (M. Smith) with packing and shipping of Pick Off Mirror Assemblies BSA1 and BSA 2 hardware to the LIGO Hanford Observatory (B. Weaver). Delivery confirmation received. Account Number P96937.
Assisted the Detector Group (M. Smith) with packing and shipping of Pick Off Mirror Assemblies BSA1 and BSA2 hardware to the LIGO Livingston Observatory (J. Kern). Delivery confirmation received. Account Number P96937.
Assisted the Detector Group (K. Mailand) with quality assurance, packing, and shipping of Clamp, Viewport Beam Dump Glass to the LIGO Hanford Observatory (B.Weaver), delivery confirmation received. Account Number P96937.
Assisted the PSL Group (P. King) with the packing and shipping of Laser Mirrors to the LIGO Hanford Observatory (R. Savage), scheduled delivery date 3-30-00. Account Number P96965.
Assisted the Detector Group (L. Jones) with the loading and shipping of a HAM Ribbon Cable Form to the LIGO Hanford Observatory (L.Jones) via United Motor Freight, scheduled arrival date 4-3-00. Account Number LIGO.5F500 2.2 NSFLIGO.5F5000.
Assisted the PSL Group with the tracing of a Pumping Station and Hoses that was shipped to Philadelphia, PA. instead of Hanford, WA. I am filing a claim seeking reimbursement.
| Packages | Faxes | |
| In | 23 | 25 |
| Out | 15 | 27 |
Special Projects: Processed a very high volume of electronic docs and there's still more waiting. Helped Linda organize, sort and distribute LIGO shirts that came in.
From: Esther Cunningham <esther@ligo.caltech.edu>
Press here for ACCOUNTS PAYABLE HISTORY DATA.
From: "Brambila, Ruth" <Ruth.Brambila@caltech.edu>
Month end began today for Payables who will be down until Monday. Purchase orders can still be issued until tomorrow, however, so I am working on Apollo and Triad to have them completed by tomorrow so payments can go out as soon as the Payables module is up on Monday.
Also will be working on OAG, and finishing up a new blanket to Tradewinds.
Have completed all requests for cancelling encumbrances and closing po's. If you have any requests, please submit them.
From: Florence Kaufman <fkaufman@ligo.caltech.edu>
http://docuserv.ligo.caltech.edu/docuserv/home/accts_ops.pdf
http://docuserv.ligo.caltech.edu/docuserv/home/accts_adv.pdf
Rita Torres
For I. Petrac formatted Attachment A for Carleton College Relativity Group (CCRG), and Attachment Z for ACIGA. Got a lesson from L. Turner on how to scan signed MOU documents. Scanned several of these which will be posted to the MOU/LSC web page. For S. Meshkov unearthed proposal pages for the 1999 Amaldi Conference, also forwarded to D. Blain in Australia.
Another pass at project for F. Asiri and DCC, to create a useable system to quickly access pertinent drawings. Project ongoing. New input from D. Lloyd to the PO log, will start today to place each entry under its respective account, then will print out summary for filing under each Poeta. Usual P-card activities, chased invoices, reconciled some. Did site trip updates. Spent more time with I. Baldon on travel documents, have completed a few.
Dorothy Lloyd
Continue to process requisitions, invoices and receiving on-line. For more detail see "Cost Schedule Control Systems" report by Esther Cunningham. Once again, the volume of incoming invoices was low.
Tracked and follow up on various invoice problems.
Monitored contract and blanket order funding levels and alerted task managers where supplements needed to be made.
Received billed amounts on-line on contracts and blanket orders so Acquisitions (Ruth) could cancel the lines out to correct account distributions, close out or remove encumbrances.
Worked on updating the PO Log Books.
Reviewed payments processed by Esther during the week of March 20. Payments were entered in contract summary sheets and the LIGO database by both Jim and me. Jim also continues to maintain the LIGO database and files.
Irene Baldon
Worked on preparing the paper work for 19 new trips taken recently or upcoming (19 Payment Requests and 12 Advance Requests). There are approximately an additional 16 new trips in various stages pending completion of travel arrangements before the paper work can be completed.
Completed 63 Expense Reports, some of which were extensive, involving 2-3 or more pages each. There are 8 Expense Reports still to be done. I'm holding 2 completed Expense Report which require a check from the Traveler before sending to Travel Audit to clear.
I have spent some time during the past couple weeks working with Rita to learn the processing of Expense Report and is progressing very nicely. Thanks Rita! Rita has completed 4 Expense Reports and has just returned another 6 to me for review and forwarding.
My Hard Drive burned last week and I was without a computer for the majority of 1 day, then was given a loaner which required several programs to be mounted. I lost some files and work for 2 days while my computer was being repaired. It was returned and most, if not all, of my files were recovered. It is still acting up and both Larry and Suresh have been made aware of the problem.
Elizabeth K. Wood
Nothing out of the ordinary. Lots of personnel stuff. On-going preparations for the NSF site review.
Progress Period from 3.24 to 3.29
Accomplishments:
General Comments:
Special thanks to Larry, Suresh, and Barbara for setting up all the
equipment we need.
I still need some submittals for the Quarterly Report for the end of February 2000.
We are preparing a schedule for the support that is going to be required for proposals, work plans, and reports for the last half of FY 2000. Clearly there is a lot of information needed, and there is a lot of overlap in the schedules that will have to be spread out given limited resources.
The following change requests have
been submitted:
| CR-990028 | WBS 1.1.3 | Beam Tube Enclosure Closeout | F. Asiri |
| CR-000001 | WBS 1.1.4 | Fencing Road at Livingston (Info Only) | G. Stapfer |
| CR-000002 | WBS 1.4 | Project Office Close Out | K. Duncan |
| CR-000003 | WBS 1.1.4.3 | Erosion Control--Livingston Observatory | G. Stapfer |
Press for the latest Contingency Needs Projection.
From: Kris Duncan <kris@ligo.caltech.edu>
Preparing to go into Preliminary Design Phase on the LIvingston Staging Building.
No report this week.
Announcements:
--------------
(F. Raab)
Folks are busily getting ready for the 24-hour
engineering run and the first
visitors to help with the run have begun to arrive.
Daniel continues to tweak
on the WFS system to improve alignment control
and Guido Mueller is up to
make the bulls-eye detector work. Rai was deeply
immersed in noise measurements
of the new lock-in circuits for the SUS sensor/actuators.
Betsy and Doug have
been working COS details with Mike S. and Ken
M. Tom Nash is also up doing some
beam scan work. The seismic installation at Hanford
is nearing completion. We
received an accelerometer, packaged for use in
vacuum, from Livingston. This
will be installed into the X-end chamber to complete
the stack characterization
work started by Joe Giaime and Andrea in Livingston.
Seismic Systems:
-----------------------------------
(C. Gray, M. Guenther & H. Radkins)
BSC9, 4K ETMx: The Crossbeams are in place at the Xend. This completes
Phase 1 of the last SEI subsystem at LHO. Over the next two weeks
we
should complete the internal installation in BSC9. There are
still CAS
cabling to lay in the LVEA and PZTs to install at three of the four
outbuildings.
PZT Calibration: Four of the PZT controllers that we will be installing
at
LHO which were used by HYTEC in the prototype unit for testing do not
have
the same tranfer properties as the production units. The prototype
units
supposedly went back to the manufacturer so all units would be the
same.
Guenther is conferring with Polytec PI and Eric Ponslet at HYTEC to
address
the descrepancy. This means the zero adjustment done in the calibration
will be performed in place rather than on the bench. That will
make the
process more involved and lengthy.
Remaining PZT stacks & their respective controllers (12 out of 16)
were
re-zeroed in the lab this week on a "free Fine Stage". One PZT
stack/controller needed adjustment, due to a resonant oscillation (we
had
this on an earlier PZT)--it was sent out for adjustment; it will be
re-zeroed in-situ because of the need for the Fine Stage out at X-end.
Meanwhile we are preparing procedures and task lists to turn to when
the
one-arm testing finishes next month.
Last week, we looked over one of V. Sannibale's Transfer Function plots
(taken
from a data run utilizing the Fine Stage PZTs) to quantify the frequency
of
each resonant peak found on the plot (these "low frequency" peaks are
primarily
modes of the BSC Stack); we utilized some documents from HYTEC as well
as a
recent document which tabulates all the current known resonances for
the
interferometer (Summary of Mechanical Resonances
in the LIGO Hanford
Interferometers [T000020-00-] by M. Landry and
D. Ottaway). The plot will be
temporarily located at this link:
http://www.ligo-wa.caltech.edu/~cgray/ETMX_LSC_I_TEMP_MIRROR_A_res.pdf
From: "Gerry Stapfer" <gerry@ligo-la.caltech.edu>
Mode Cleaner Commissioning (J. Kovalik)
We have made a prioritized list of tasks needed to commission the mode
cleaner. This week we have gone back to characterize some of
the
measurements started last week.
We measured the intensity transfer function of the mode cleaner and
obtained a pole frequency of 4314 Hz +/- 57 Hz.
We also performed a ringdown measurement of the cavity by driving the
intensity of the laser with a square wave. The ringdown time
of the cavity
was 7.41+/-0.78 e-5 seconds. The ringdown down for the light
itself going
into the mode cleaner (the switching time constant of the laser)
was 4.75
+/- 0.44 e-5 seconds. We need to deconvolve this data and see
if it matches
the pole frequency of the transfer function.
We measured the Q of MC1 and found that there were 3 frequencies near
28
kHz. There was one at 28.1645 kHz with a Q of 2.24 +/- 0.19 e5.
This had a
small splitting with a side peak at 28.1665 kHz. A bit further
away at
28.239 kHz, we saw another peak with a Q=7.29 +/- 0.21 e5.
This last peak
matches the Q's of MC2 (f=28.235kHz, Q=8.46 +/- 1.8 e5) and MC3 (28.239
kHz,
Q=7.14 +/- 0.15 e5). We are now studying why we have these extra
peaks on
MC1 and looking again on MC2 and MC3 if they have any also.
Optics: The RM, Beamsplitter and both ITMs have been re-hung, and are
being
balanced. Alignment fixturing completed for IOT-1. Reflectivity measurements
made on 635nm viewports examining their efficacy at 670nm. Fixturing
fabricated for baking COS beamdumps. (Jonathan Kern)
All MIT activity reported in other categories.
All CIT activity reported in other categories.
| Installation:
Livingston |
Commisioning:
Livingston |
Other Science/Engineering
Activities |
With both the alignment control engaged and running a high bandwidth length servo loop the arm cavity stayed locked continuously for 10 hours! (before we gave up)
Rolf Bork
Completed setup of ASC/LSC test stand at Wilson house.
Rewrote LSC servo code using ASC generic vme and communications modules.
Ran timing tests to verify code performance. Initial tests on Pentium
III indicate can read 16 ADC channels (12 presently defined), perform the
servo calcs, and output DAC channels in ~30usec. Writing DAQ channels takes
an additional 10usec. Need to run additional tests with GDS TP/EX enabled,
but it looks like we fit "comfortably" within the required times.
Matt Smith
Finishing up the redesign and fabrication for the new ETM transmission
monitor assembly. The final piece is in the machine shop and should
be finished this week. The new version will not require the pier to be
rotated as previously thought. However there is a .75 difference
in position of the beam line, so the pier will have to be translated by
this amount.
Since our last report, we have suspended the remaining
optics for our
triangular mode cleaner. Alas, while we were installing the fins
on the
last mirror (we are using old-style, split-photodiode OSEM's), the
side
magnet broke off again and will have to be reinstalled over the weekend.
As of last report, we had two working OSEM controllers
and several others,
obtained from the old 12-meter mode cleaner prototype and from CDS,
in
various states of disrepair. We fixed one on Tuesday and now
have the full
set of three necessary to lock our mode cleaner. The problem
in the
controller we fixed was an intermittent contact in the wiring between
boards, which prevented the yaw error signal from being passed on to
the
output matrix. One of our other controllers exhibits the same
behavior,
and we expect it will also be easy to fix.
We now have three mirrors, two of which successfully
damp in all modes,
and one of which successfully damps in everything but side motion.
We have
begun rough alignment of the cavity using a Helium-Neon laser, and
that is
coming along nicely. We will wait until we have reinstalled the
side
magnet for final alignment.
Eric's paper on Pound-Drever-Hall
locking was accepted by the American
Journal of Physics. His and Robert Cameron's
paper on thermal noise in
coupled oscillators was received by Physics Letters
A and is now out for
review.
(vacuum envelope)
A new wiring error
crept in during an update to our vacuum interlock
panel last week.
(lab infrastructure)
Ed K. and MIT crews completed re-cleaning of the high bay and returned
it to cleanroom "booty" mode. We are watching the particle counts
come
down. (NB: we deliberately breached cleanliness protocol last month
for
rigging and uncrating of SEI components).
There is a new wave of heavy construction (including pile driving!)
going on nearby in Cambridge. MZ is resurrecting the bandlimited RMS
seismic monitoring station so we can plan work for quiet times.
So
far it only seems to affect an hour or two here and there.
Good simulation work at VIRGO
Luca gave a Physics talk on Tuesday, showing how he used the simulation
(SIESTA) in his work for the locking study.
He is working to implement WFS in the simulation of LHO 2K FP system,
and soon the coupling of LSC and ASC will be studied.
adlib
In the weekly meeting, Hiro summarized a tentative development
plan in this year. Next week, further plan extending to next year and
beyond will be discussed.
The strategy of the in-lock state simulation was discussed, in which
very large range - micro seismic peak to the bottom of the noise curve
-
needs to be simulated.
PSL modeling
Last Friday, Rick, Biplab, Matt and Hiro had a telephone conference
to
discuss about the modeling of various possible noise sources of PSL.
Biplab developed a module which is necessary to simulate the motion
of the detector (actually move the beam with detector fixed).
alfi
A few more test versions were released, but still not ready for wide
use.
This week the focus was on fixing bugs that showed up during
testing of the the pre-release LDAS 0.0.10 version. The tests
resulted in 27 new problem reports last week (a little over
double the usual weekly count) while in the same week closing
out 27 problems, leaving us with no net gain for the week. We
now have code that is in good shape. All remaining problems
can be postponed until the next release and will not effect
any usage of LDAS that is planned for next week.
The work on the new LDAS webpages are almost finished. Barbara
has added several fine touches to the top level LDAS pages. It
is expected that the development version she is working on will
be moved over into the main stream at the end of this week. Also,
the automatically generated PERCEPS documents for LDAS code were
reviewed this week and several problems with C++ code that caused
parser problems for PERCEPS were identified and later fixed.
Work on the version 4 compatible FrameCPP continued this week. A
few more inconsistancies in the spec were identified. Most of the
remaining code development is related to the new Table of Contents
structure which will be used to improve read times of frame files.
The wrapperAPI/UWM team and the dcAPI team held their weekly
meetings this week. The momentum on these two LSC inclusive
projects have returned to the pre-LSC meeting level. There one
area of concern was the ability to support hierachical searches
within the wrapperAPI. It now looks as if this will not be a
problem. There is a standing question about making a minor change
to the code flow and command line options to the wrapperAPI to
support a possible efficiency issue. A solution has been proposed
by the CIT team and UWM will explore its impact and report by
early next week.
Stuart Anderson:
Identified and begun to diagnose
a data corruption in the CACR
HPSS archive that effects high speed data retrieval.
Help identify with Omar a
potentially serious performance problem
with the FORE Ethernet switches.
Upgraded software mirroring
tools and reconfigured to include
distribution of the new 6.2 version of RedHat Linux
Transients Identification (Julien Sylvestre)
----------------------------------------------------------------------------
JS worked on the implementation of a transients identification pipeline
for the
one arm LHO data and the 40m data. Transients characteristics (duration,
frequency range, shape, correlations with PEM channels, etc.) are being
catalogued.
Christine is setting up a site license server, to serve licensed
software to all the site networks: CDS, LDAS, GDS, GC. The Matlab
and
Mathematica licenses have been transferred.
CIT:
Samantha set up a printer on the third floor and worked with a number
of people
and their pc's.
Set up Calendar tool on Irene's computer.
Suresh replaced bad hard drive with new one of Phil Williems's Gateway
PC at his
Lauritsen lab, installed window 98 and put on 125 subnet.
Started monthly full backup of LIGO servers.
Assembled two computer projector carts to be used for the computer
projector
system.
Set up a Windows NT workstartion and put in 115 subnet in third floor
conference room to run premavira application.
Got help from a computer company (High Performance Computers) to replace
broken hard drive of Irene's PC and transferred all the folders/files
from old
one to new one. Moreover her critical folders are copied in her network
drive.
So, in case of future drive failures, she can run those application
from network
drive.
Barbara made a number of web site changes -- links to the KipFest and
a CACR
job, more conferences, links to Inauguration videos and photos.
Have a revised
home page to review with Gary next week.
Larry worked a couple of pc orders. The order for Livingston is now
being
shipped there from Caltech Wired. Presently, they are not drop shipping
to the
Observatories.
Worked a couple of secure shell issues. Most were simple setup issues
on the
PC's.
Worked on the NT server room. Getting quotes for a UPS to be used with
the
equipment.
Fixed a number of PC's. Most of the problems were taken care of with
the Norton
Utility program.
From: Jordan Camp <jordan@ligo.caltech.edu> SAPPHIRE
An initial set of absorption measurements have been done at Stanford
on a
set of 3 different sapphire starting materials. Measurements were done
of
absorption at 1064 nm, absorption at 514 nm, and induced fluoresence
of a
titanium absorption line (titanium is a known contaminant in sapphire
which
is suspected of contributing to the 1064 nm absorption.) Samples were
taken
from locations in the top, middle, and bottom of boules grown from
each
starting material, to investigate the possibility of segregation of
contaminants. It was found that 1) the absorption at 1064 nm varied
from 40
ppm/cm to 120 ppm/cm, with an average value of about 80 ppm/cm, with
no
clear correlation with starting material or boule location, and 2)
the
absorption showed no correlation with the level of titanium concentration,
indicating that titanium is not the only contributor to the absorption.
Some additional measurements are being undertaken, after which Crystal
Systems will discuss with us the composition of the different starting
materials used in the measurements, so that other possibilities of
suspected contaminants can be pursued. To put the absorption value
into
perspective: at the LIGO II power level of 6 kW in the recycling cavity,
the measured average absorption of 80 ppm/cm will cause a thermal
distortion in a sapphire ITM of ~1000 nm. This level of distortion
may be
very hard to externally compensate, which points to the importance
of
identifying and reducing the impurities leading to the sapphire absorption.
From: GariLynn Billingsley <Billingsley_G@ligo.caltech.edu> POLISHING, COATING, METROLOGY
A quote was received from CSIRO for homogeneity measurement of 2 m-axis
sapphire blanks. A change order to CSIRO has been drafted for
this
work. The latest delivery estimate from Crystal Systems is in
mid May,
about a month and a half past their initial estimate.
A LIGO II pathfinder drawing and polishing specification are complete
can
be found at http://ligo.caltech.edu/~gari
From: Sam Richman <srichman@ligo.mit.edu>
Stiff isolation system (S. Richman, J. Rollins, S. Chatterji, G. Hammond,
J. Giaime)
The second set of six L-4C (1 Hz) geophones from Mark Products arrived
and
were installed on the lower stage of the isolation system. These
seismometers and their associated actuators were tested and found to
be
working. The aluminum position sensor targets were replaced with
steel
targets; the operational range of the sensor is now 2-4 mm from the
face of
target.
The three vertical isolation loops on each stage were closed around
the
geophone signals. 45 dB of isolation at 10 Hz was measured using
independent seismometers on the ground and on the lower stage.
An
interaction between the three vertical loops near their upper unity
gain
points (~40 Hz) is limiting the gain that can be achieved. We
are thinking
about a second cut at a control algorithm to address this issue.
Work also continues on the characterization of the upper stage horizontal
loops. This is not made any easier by our particularly unfriendly
seismic
environment - pile driving at a construction site ~100 m from our lab!
From: Mike Zucker <mike@ligo.mit.edu>
Thermal compensation of core optics (Lawrence, Zucker, Fritschel)
-----------------------------------------------------------------
Last week we worked on calculating the effect of time-varying thermal
expansion due to beam heating in sapphire LIGO II COC substrates &
coatings. This was raised at the LSC meeting as a concern for
the
proposed directed-beam heating solution for core optic thermal
compensation. It appears that direct
beam actuation on the sapphire
ITM's won't work using currently available
technology for the heating
laser (intensity is too noisy). We
can fall back and instead apply the
compensation to the recycling mirror, beamsplitter and (possibly) an
added compensator plate (or symmetrized beamsplitter). These items
are
outside the cavity and will probably be fused silica as well
(relatively immune compared to sapphire). Pure radiative correction
solutions (hot rings, shields & reflectors) are not affected
by this
issue.
In looking at this we stumbled across a related
but more basic problem,
thermal expansion noise due to fluctuations in the interferometer light
itself. A quick and dirty calculation (T000040-00-R) is not
comforting. It turns out Braginsky, Gorodetsky and Vyatchanin
looked
at something related, but neglected a bulk absorption component to
the
effect which may be significant given the measured bulk losses in
sapphire (this effect is also hard to calculate). Ryan is setting
up
his finite element code to directly simulate the situation. For
now
we will do the thermal problem and elastic problem separately; they
are reasonably separable in this regime.
On the experimental side, the CO2 laser controller was repaired and
returned to us. Ryan is now finishing up the electronics to drive the
beam directing galvos.
From: Phil Willems <willems@ligo.caltech.edu>
Fused silica fiber work:
------------------------
Phil spent two weeks in Moscow measuring the Q
of a torsional pendulum made
using Caltech fibers, a Glasgow pendulum bob,
and Russian facilities. The Q
was measured to be ~6.4e7- good, but less than the record of 2.3e8
measured
using the Glasgow bob and Russian fibers in the same lab. There
are many
possible reasons for the low Q: the fibers were made using less expensive
fused
quartz, the fibers were made in Pasadena and brought around the world
to Moscow
before assembly (yes, they passed customs), and the pendulum had not
been baked.
The 2.3e8 value was only achieved after baking. It is also possible
that
lathe-drawn fibers are inferior to hand-drawn fibers. Further
studies are
needed. An attempt to bake the pendulum appears to have deposited
some
contamination onto the pendulum mirror and perhaps onto the fibers,
so a
post-baking Q measurement may not be meaningful. It is worth
noting that the
material losses and dilution factors of both pendulums imply Q-factors
much
higher than measured, so the measured values are still strongly limited
by
causes that are not understood. Bol'shoe
spasiba to the Moscow group for their
generosity and patience during Phil's visit.
(Phil Willems, Kirill Tokmakov,
John Johnson, Valery Mitrofanov)
Meanwhile, at Caltech, John Johnson has measured the tensile strength
of
hand-drawn fused silica fibers using a new chucking technique for stressing
the
fibers and found strengths for thin fibers averaging about 4.5 GPa.
For thicker
fibers (D>150um), the glass seems to break in the chucks. We
have demonstrated
this by measuring the strength of undrawn rods chucked in an identical
manner-
they break under the same load as the thick fibers, but unlike fibers,
which
shatter competely no matter where the break initiates, the rods broke
only at
the chucks. Many of the thinner fibers show breaks in the chucks,
so their
strengths may also be chuck-limited. We are working to improve
our chucking
procedure, and to build chucks that will mount in our lathe, so that
we can also
test lathe-drawn fibers. (John Johnson, Phil Willems)
Hydroxy-catalysis bonding:
--------------------------
The strength of the hydroxy-catalysis bonds made at Stanford seems to
be
hovering at about 250 lbs. of shear for a 1/2"-diameter bond.
The bonds cured
for the first three weeks at 100% relative humidity and room temperature;
however, immediately after removing the bonds from the humid atmosphere,
crystallization of potassium hydroxide could be observed in real time
under a
microscope, indicating that the humidity was retarding some portion
of the
bonding process. The bonds have been allowed to dry out in ordinary
Pasadena
air since then. Many of the bonds now appear 'cloudy.'
(John Johnson, Phil
Willems)
From: James Mason <jim@ligo.caltech.edu>
RSE tabletop prototype (Jim Mason)
Since the last report (approx. 3 weeks), the
full RSE interferometer
prototype was successfully locked, and transfer
functions measured.
Lock acquisition is pretty magical, although
not particularly
difficult. Basically, all servos
except the Michelson are turned on,
and the beamsplitter is dithered by hand slowly. At some point,
usually within a minute, the system locks, after which the boosts are
engaged and the Michelson is also locked. The locking was very
stable
and robust, lasting for 1.5 hours, which was when we turned it off.
Similar ease of locking and robustness of lock was achieved the
following day after careful alignment. The work was done with the help
of Gerhard Heinzel and Osamu Miyakawa, who were visiting from TAMA.
Success is attributed to softening up the optics (lower finesses),
and
more careful attention to gain margin in the servos. Most problematic
is the arm cavity DM servo, which gets its signal from the dark port,
through the signal cavity.
Initial lock was in broadband mode, and it was discovered that for
detuned mode, much better control of demodulation phase is needed than
what exists currently in the RSE lab. Currently, work is being done
to
design and build some nice voltage controlled phase shifters, with
the
consultation of Rich Abbott.
From: Riccardo DeSalvo <desalvo@ligo.caltech.edu>
SAS R&D
Hareem, Chenyang
Finished measurements on the new zero force gradient 2-dimentional
non
contacting forcers. They provide a force uniform much below the
percent,
close to the per-thousand within a surface of about 15 times 15 mm2.
Power
consumption negligible.
Akiteru
Made preliminary simulation of HAM table seismic isolation. Out
for JPS.
Virginio
First measurements of LVDT/forcer transfer functions on the IP, using
the old
forcers. Diagonalisation of the f.b. matrix.
Virginio, Szabi
Starting tuning of IP counterweight using the LVDT/forcer t.f..
Szabi
Feeding LLO seismic data into MSE.
Alessandro
Tuning up accelerometer on minus-K platform, getting ready for IP tests,
setting up 20 micron joint electropolishing procedure.
Hareem, Chenyang
Wiring Creep test LVDTs.
Promec
Produced interface plates to mount new forcers in place of old ones.
Last
touches of TAMA drawings. Starting revision of second accelerometer
prototype. Penn State GAS design.
G&M
TAMA IP continuing production
TAMA filters started production
MGASF blade tester ring to be ready next week
New ring for low frequency tests of old GASF should be shipped any
time.
For additional information about this report, contact sanders@ligo.caltech.edu