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The LIGO Executive Committee
Agenda for Monday June 26, 2000 will be:
(Meeting time: 10:30 am Pacific Time)
Open meeting 10:30 - 11:30
Special Items: Cost/schedule performance and contingency
First fringes were seen
from a recycled Michelson in the LHO corner station
No report this week.
WBS 1.2 LIGO Operations--Administration
From: Ed Chargois <chargois_e@ligo.caltech.edu>
From: Cleveland Mak <mak_c@ligo.caltech.edu>
From: Esther Cunningham <esther@ligo.caltech.edu>
Press here for ACCOUNTS PAYABLE HISTORY DATA.
From: "Brambila, Ruth" <Ruth.Brambila@caltech.edu>
Just received a new change order today for Triad.
Have been placing credit card orders for merchandise.
We will begin entering the new blanket PO's for the campus today for the new fiscal year. The PO's have been distributed throughout the department. I received my list of the PO's to be entered.
Still holding Northwest and Syracuse University until POETA 50498 (Visitor's Program) is extended.
Insurance issues for long-term visitors and students working on the sites during the summer have essentially been resolved. Caltech worker's compensation will be the default solution for those long-term visitors who are not covered by their home institution for some reason. This will not apply to minors, however, who will have to be covered by either their parents insurance, or special insurance furnished by the organization that sponsored them.
Rita Torres
For I. Petrac continued to investigate why some Attachments and reports did not appear on the MOU/LSC page. Worked with B. Kratochwill and C. Mak to correct this. Scanned more documents for posting on the web page. Did FedEx to VIRGO to transmit Attachment No. 3 for signature. Letters to TRW and Laser Zentrum/Hanover Re: upcoming visit by LIGO team.
Arranged for an eye exam, did site trip updates, did some travel documents. The usual Pcard activity -- chased errant invoices, reconciled 29 this period. Started update to D. Lloyd log of LIGO accounts, will continue to do over the next few days.
Irene Baldon
Worked on preparing the paper work for six new trips taken recently or upcoming (seven Payment Requests and five Advance Requests). There are approximately an additional 10 new trips in various stages pending completion of travel arrangements before the paper work can be completed.
Our SURF Students have all arrived safe and sound and have started to submit expenses for reimbursement. Riccardo DeSalvo had his students come in a week early to start working with him. These students were housed off Campus using his account number.
Completed 26 Expense Reports, some of which were extensive, involving 2-3 or more pages each. There are 14 Expense Reports still to be done. There are no Expense Reports presently being held for a check from the Traveler before sending to Travel Audit to be cleared at the present time.
Rita continues to try to fit into her schedule some time for travel. She has no Expense Reports to be done at this time but has completed six previously taken reports for final review.
I haven't heard anything on the progress of LIGO obtaining Travel P-Cards.
Prepared the Travel/Vacation Itinerary for the Week of June 19, 2000 and a Revised Edition on June 20, 2000. Performed normal recording and filing associated with Travel and Reimbursement. Worked on several problem issues with Travel Audit.
Dorothy Lloyd
Processed requisitions, invoices and receiving on-line. For more detail see "Cost Schedule Control Systems" report by Esther Cunningham. Tracked and followed up on invoice problems.
Monitored contract and blanket order funding levels and notified task managers when supplements were needed.
Continue to review "old" open purchase orders. Submitted an additional 22 to Acquisitions (Ruth) to "close out" and remove the encumbrance. This has amounted to approximately $127K to date. LIGO database was adjusted accordingly.
Jim returned from Jury Duty this week and has been catching up on data entry. In Linda's absence, he also helped Cleveland out in the DCC.
Elizabeth K. Wood
Continued the process of hiring people for the two sites and working on visa issues.
I have placed just about everybody I can into slots and offices. NB: Please let me know when your people are coming and where you plan to put them. There have been instances of new people being placed in offices without my knowledge. We're short on space, but I really don't want to start double-decking until it's absolutely necessary.
Worked with Cindy Akutagawa to make a list of what accounts everyone in LIGO is paid out of. As a result of this exercise, I did some retroactive account distribution changes. It turns out that it’s entirely possible for errors to creep into account distributions that are not the fault of anyone at LIGO. I spent some time fixing errors made on the "approval" end of the ORACLE/LDA system..
Progress Period from from 6.16 to 6.22
Accomplishments:
The following change requests have
been submitted:
| CR-990028 | WBS 1.1.3 | Beam Tube Enclosure Closeout | F. Asiri |
| CR-000005 | WBS 1.2.1 | Upgrade Pre-stabilized Laser | S. Whitcomb |
| CR-000006 | WBS 1.2.1 | Re-polish Core Optics Components | S. Whitcomb |
| CR-000007 | WBS 1.2.2 | Replacement of Optical Lever Lasers | S. Whitcomb |
| CR-000008 | WBS 1.1.4 | Cameras and Projection System at LIGO Livingston Observatory | F. Asiri |
| CR-000009 | WBS 1.1.4 | Cameras and Projection System at LIGO Hanford Observatory | F Asiri |
| CR-000010 | WBS 1.2.2 | Redesign Suspension Controllers | S. Whitcomb |
| CR-000011 | WBS 1.2.2 | VME Development System and Spares | S. Whitcomb |
| CR-000012 | WBS 1.2.2 | ASC/LSC Rework | S. Whitcomb |
Copies of these change requests have been distributed to memebers of the LIGO Change Control Board (See LIGO-M000176-00-P).
Press for the latest Contingency Needs Projection.
From: Kris Duncan <kris@ligo.caltech.edu>
No report this week.
Announcements:
--------------
(F. Raab)
The first fringes were seen from a recycled Michelson in the corner station. Fringes looked quite nice and uncannily stable, considering the only feedback was OSEM damping.
Gregory Mendell has arrived and is putting our LDAS affairs in order (see below).
Electronics for the 2K Michelson are being installed.
Comments were submitted to the Port of Benton, concerning a proposal to mine gravel approximately 10 miles from the Y arm.
The Washington Department of Revenue has informed us that LIGO Hanford Observatory is not subject to the business and occupation tax. They state that less than 1/2% of the project spending may be subject to sales taxes and will refer to another unit of the Department to sort this out.
Bake Oven:
----------
(K. Ryan)
LHO Vacuum Bake Oven A Load #94, consisting of LHO Elliptical Baffle parts, LHO Tanner Mount Components and misc. hardware, was released on 6/6/00. The turbo pump failed midway through this load necessitating pump replacement and a prolonged bake cycle.
VBO A load #95, consisting of Arm Cavity Baffle Glass, Elliptical Baffle Components and Tanner Optical Tower Mount Components, was released on 6/13/00.
VBO A load #96, consisting of ETM PO Telescope Alignment Fixture and Elliptical Baffle fasteners + misc. SS fasteners was released on 6/19/00.
VBO A load #97, consisting of Elliptical Baffle Components, Table Clamps and OSEM Cables, is vacuum making now and should be released on 6/26/00.
Oven A will be out of commission during the week of 6/26/00 for upgrades and routine maintanance. Vacuum Bake Oven B components are arriving daily.
Seismic Systems:
----------------------
H Radkins, M Guenther, C Gray
CAS
All BSC1 motor, limit switch, emergency stop, air bearing switch and
encoder cables have been installed with the exception of those on motor
V1.
Motor V1 has not been installed yet; this is expected by the end of
this
week. Thanks to Hytec for their prompt fabrication and shipment of
a W
motor limit switch cable.
A bad connection was found on the 2-channel rack computer keyboard;
it was
swapped with the mobile rack keyboard for now.
CAS software database work continues. We are seeking a change to allow
control over which BSC (and its motors) are first accessed by the software
upon powerup.
The bulk of the pneumatic components have been received, the remainder
are
expected within a week.
STACK TRANSFER FUNCTION
Testing for nominal parameters for the BSC in vacuum transfer function
measurement continue. We are insuring the shakers are working in
unison and the sweep will provide good S/N.
SEISMIC NOISE
Seismic time series are being collected at various wind levels to determine
correlations.
The Hanford site sprayed for weed control last weekend using a helicopter.
We monitored its position and will correlate to seismometers and microphones.
Szaby Marka was here last week and we collected spectra for Trinet
site location determination.
TILTMETER/TEMPERATURE
No work has been done on this issue this week. It still stands
that temperatures affect the tiltmeter more than just at the tilt sensor.
LIGO-Trinet
-----------
S. Marka, C. Gray and H. Radkins
We have the candidate location for the LHO station: ~200m perpendicular
to the beampipe at the 1Km mark of the X arm. Hugh and Corey will take
some additional measurements at this location to make sure that the
noise is always low.
LHO LDAS
----------
G. Mendell
The current activity is:
1) Checking on the shelving for the beowulf cluster.
The pieces that
are here at LHO have the manufacture's part numbers, while the PO has
the supplier's stock code numbers. I am checking with LDAS at
Caltech
and the supplier to make sure the right parts are here.
2) Coordinating with Dave Barker to move the CDS racks and LDAS
rack
across the mass storage room to make room for the beowulf cluster.
This
must also be coordinated with Otto and the fire department to turn
of
the fire sensors below the floor. Power and air conditioning
requirements are also being worked out for the room.
Near-term future activities will include:
1) Shelving needs to be moved out of the staging building, e.g.,
to the
warehouse (or the mass storage room if room has been made).
2) Installing more fiber between the mass storage room and the
computer
users room for more LDAS computers.
3) Installing a Sun D1000 288 GB disk unit to the LDAS dataserver.
4) Operating system upgrades of the LDAS Linux boxes.
The long-term plan is to install (or order?) the beowulf cluster around
December of this year.
OPTICS/COC INSTALLATION: IO Baffle installed in HAM-2. Various COS aluminum components recleaned and rebaked successfully. Last COS bakeload is in the oven now. Beamsplitter was installed in BSC-2, but we were unable to align it. We learned that there are some inconsistencies in E990083 regarding the direction of the surface normal. Mike Smith verified the correct global tilt of the HR side of the Beamsplitter, and Mark Barton converted to the local tilt. They confirmed that the BS had the sign reversed on the E000028 doc, and the BS was hung wrong. The solution requires removal and replacement of the standoffs, guide rods and magnets. We began this task yesterday. We need to re-bake the BS; at best it will be ready for re-balancing next Wednesday. (Jonathan Kern)
SOS Installation: We continued preparing MC1, MC2 and MMT1 that will be installed in HAM replacing the current ones that have PAM magnets. All three optics have been balanced and are ready to be baked. New alignment centering fixtures with irises have been cleaned and are ready to be used for realignment of in-HAM optics. (Sany Yoshida)
Note: In circulating draft contributions to the weekly, several additional comments were generated in response to Sany's initial report, and these comments are appended here because they provide some additional information that might be of broader interest:
Additional remarks from Hai Sheng Rong:
1) In the process of preparing the SOS we noticed that the spring tips
of
the safety stops are magnetic. The balance angle changes slightly but
noticeably when we move these screws in and out.
2) We observed slow drifts of the mirror balance angle after the mirror
is
balanced and before the second (balancing) wire standoff is glued.
The
drift rate for that particular mirror was 0.3 mrad/12h. This observation
disputes the presumption that the drift happens during the glue curing
process
Comment from David Reitze:
These are steel springs. They probably are not permanently magnetized
but
do gain a moment in the field of the magnets on the mirrors. We'll
try to
find either stainless or phosphor-bronze springs.
Response from Sany:
But I have also observed (a couple of times) much larger and faster
drift
after putting glue to the second wire standoff.
When I put glue to the second wire standoff yesterday, I observed the
following. The balancing angle was 0.25 mrad. I put glue at 5 pm. For
10
min or so, the mirror did not drift (i.e., the optical lever signal
on the
scope did not change) so I left optics lab. About 8 pm I went back
to
optics lab to check the status. I found the optic drifted upward by
0.6
mrad. I adjusted the position of the wire at the bottom of mirror (
so that
the mirror would go downward) and this worsened the problem. The mirror
shifted by another 0.5 mrad or so. I was desperate and decided to rework
on
the mirror. So, I took off the bracket holding the top safety screws
(so
that I could take the mirror off the wire). Then, as soon as I took
the
bracket off the tower, the mirror came back to the initial balancing
angle
(~0.25 mrad). The mirror swung when I took the bracket off. After the
mirror became quiet (by the way, the OSEM control was always on during
the
cure), I put the bracket back. This did not change the angle. Then
I went
home. When I went back to optics lab this morning, the balancing angle
was
0.15 mrad. I do not understand this.
Sany
PSL: We are continuing to change mounts and realign the optics in the PSL.
General computing: We have received an order of Gateway PCs, and are configuring them and installing software. We are also re-distributing some of the PCs for the use of the summer students and visitors.We are taking a survey of our network cables and hubs to determine if we need to increase our capacity. We have a summer student, Sarah Newman, assisting us for the next several months.
GDS LLO: We are installing a temporary chasis for the excitation
engine (1X5) until we get the final chasis (~09/2000?). (Szabi, Keisha
Williams (SURF))
All MIT activity reported in other categories
All CIT activity reported in other categories
| Installation
& Commissioning:
Livingston |
Other Science/Engineering
Activities:
Issues/Concerns |
See also the Installation web page
The flooring in the LVEA has started, so commisssioning activities will be a little slower for the next couple of weeks while we are in laser safe mode during the days.
3 elliptical bafflesCabling for the 4K IFO cameras and illuminators has been completed.
3 pickoff mirrors
1 ETM telescope.
We are working on a plan to commission the PEM subsystem.
The current shunt for SN #107 was modified to include the high wattage 10 ohm resistor. The transfer function of the shunt was measured and found to be 15 dB higher than the one installed on the LHO 2k PSL.
A trial intensity servo was modeled in Matlab. The servo modeled was patched together on the old intensity servo card and tested. It was found that the servo gain could not be raised beyond 80 dB. A check of the gain stages in the servo showed that things seemed to be behaving properly. The actuator transfer function was re-measured out to 2 MHz, this time, to reveal a peak in its response (previous measurements were limited to frequencies below 100 kHz) at just over 1 MHz. The peak might be related to the relaxation oscillation. A check will be made to see if the "noise eater" circuitry of the NPRO oscillator was operational.
6 SOS controllers are being assembled and tested to support the LHO 4K installation schedule. It is the current plan to use these controllers as portable controllers during the installation and install the permanent suspension controls as time permits.
Mark Barton
I tidied up the PAM model
I had been working on and released it for use by interested people. I made
preparations to go to LHO 6/25 to 6/30) to work on suspension controller
tuning. I calculated the surface vectors of the optics in local coordinates
for use in suspension balancing as a crosscheck for an earlier tabulation
which was suspected of having errors.
Janeen Romie
Working procurement of new
osem parts.
Last week one of the things we reported was that
we had locked our mode
cleaner in the p-polarization state, and then
dialed it over to
s-polarization while maintaining lock.
Stan has since pointed out to us
that the s and p-polarization modes are separated
by half a free spectral
range, and we now suspect that we were locking
in the s-polarization mode
(finesse of 5,000) all along. Rotating
the polarization may have simply
reduced the intensity of the s-mode (because
the alignment is not exact),
which reduced the overall gain to make lock acquisition
easier. One of the
things we noted as we turned the polarization
over to the s-state was that
the transmitted intensity increased dramatically
from what we took to be
the p-state, and this is consistent with simply
changing the intensity of
the resonant state.
We remain confident that really did lock to the
5,000 finesse mode
directly, as we reported last week.
This week we broke vacuum and have mainly been preparing for installation
and lock acquisition of the complete instrument. In the background,
we
will be measuring transfer functions and noise levels in the mode cleaner,
but the main focus will be on assembling and installing the hardware
for
the complete interferometer.
Congratulations to Luca and Christina Matone
on the birth of their new baby
boy, Leonardo!
Nothing significant to report.
Simulation and Modeling:
Mechanics SImulation
Giancarlo Cella is visiting LIGO since June 16. The AIP
of
MSE for e2e has been finalized, and Cella wrote a new
class
for this API. Cella wrote two systems wrapped by this
class,
one a simple suspended mass and other other the reference
cavity of PSL. Cella and Ed Maros worked together
to install
MSE code to e2e CVS.
Cella and Hiro discussed about the collaboration between
VIRGO
and LIGO in the simulation work. VIRGO now appreciates
the
value of MSE, and the collaborative effort will benefit
beth
of us. A memo suggesing this was sent to Barry, Gary
and Albert.
e2e at LHO
Biplab visit LHO this week.
Biplab, Rick and Brad Zampft (summer student) discussed
about
the simulation work of the PSL system. The simulation
of the
reference cavity was one of the issues to be done. Cella
will
send the time series data after he goes back to Italy.
Also, the reference cavity primitive will also be available
soon.
Biplab and Ed tried to update the entire e2e stuff at
LHO, but
it turned out that the unix softwares are too old and
softwares
could not be built. The unix softwares will be updated
in one way
or another. Ed is leading this.
adlib
Hiro worked on implementing the macro and expression parser.
GUI (alfi)
More alfi bugs were fixed, and getting better condition.
Version 3 of alfi can no more be maintained even if bugs
are
found, and alfi on LHO and LLO will be updated to version
4
asap.
LDAS Software:
Blackburn:
A new database was added to the LDAS GNATS problem
tracking system in support of the LDAS hardware
procurement. The system is in prerelease form but
looks just like what we will need to track hardware
procurement at each of the LDAS locations.
The wrapperAPI has now been ported over and tested
on the LDAS beowulf hardware. Several Unix configuration
problems showed up in our early tests. The Beowulf
had not been used for anything as complex as our LDAS
system prior to this port. Other minor issues included
having a buggy version of MPI and very old compilers.
The current activity for the wrapperAPI project is to
develop test data sets using the LDAS ilwd format. We
are also waiting for the dynamically loaded shared
object being provided by UWM to be completed and ready
for testing. The mpiAPI which the wrapperAPI must
communicate instructional information with in the LDAS
system is also still under development.
The LDAS system is finally in stellar condition again
after several months of bug fixing and enhancing in a
effort to prepare a version to support the types of
data collection activities associated with the first
engineering run. We are hoping to have a release in a
day or two. This release would have stable APIs and
reliable communications as well as support for trigger
data insertion into the DB2 tables. This has all been
made possible by tracking down a bug in the ldas thread
code that allowed uncontrolled modification of a state
variable. All critical problem reports for the software
either have been or will soon be closed out.
The dataConditionAPI received significant attention
this week with efforts now underway to implement the
TCL layers which will be responsible for starting up
and managing analysis chains, communicating with other
LDAS APIs and directing conditioned data results to
users and the parallel computing components of LDAS.
Shawhan:
This week I have spent some time prototyping the communication
pathways to be used with the "Local Data Manager". The
LDM
uses sockets to communicate both with user clients and
with LDAS,
and is event-driven so it can do multiple things at once.
The user
clients themselves, on the other hand, will communicate
synchronously
with the LDM (e.g. if asking for some data, they will
block until the
LDM tells them it's available), which makes the client
interface
simple. After some initial playing with Tcl clients (easy),
I spent a
while coming up with a working C client. It also seems
that Matlab
can be easily supported using the unix('cmd') function,
which execs
the cmd and returns the result.
I haven't made the LDM actually do anything yet--i.e.
I haven't put
in the connection to LDAS, or defined the syntax for
commands and
queries--but I'll work on that next week.
Lazzarini (reporting from GEO):
Attended a GEO Data Analysis internal
meeting as a
LIGO Observer. Provided a brief
overview of LIGO
plans/designs for data formats,
databases and
storage systems. The GEO design
is much less well
defined than ours and there was
discussion of
whether GEO should/could adopt
wholesale the
relational databse design we have
developed. I
indicated that we would be willing
to share it
with them.
They are starting to have issues associated with
how experimentalists and theorists will interact
once data starts to flow. Part of this seems to be
related to the fact they do not have a "detector
characterization working group". They are in the
process of forming one with 3 members each from
Cardiff/AEI and GLasgow/Hannover
They are seriously pursuing a "geo@home" plan to
implement distributed opportunistic computing on
workstations across the geo collaboration not
directly owned by GEO. machiens at
Golm/Berlin/Hannover/Glascow/Munich/Cardiff are
their targets. Their figure of merit is:
available GFLOPS = 100*(efficiency_of_usage/0.5)
*(N_machines/100)*(N_institutes/5)
*(CPU_MHZ/400).
i.e., if all 5 institutes have each 100 machines
that can be used 1/2 of the time and they have
400MHz processors, then they claim they can get an
additional "free" 100GLOPS for CW searches. They
are modeling this after the seti@home software
(screen savers, background unix jobs). However
they are reinventing everything rather than
talking to the seti people.
GEO has pruchased a small DEC alpha beowulf
cluster forthe Hannover site. They arrived at this
in a $/GFLOPS trade study (got a very good deal
from Compaq/Europe). Bernie will put us in touch
with the US counterpart of the alhpa academic
technical representative. AEI has close ties to
DEC/Compaq because the European manager is a
relativist.
Triana has been augmented to allow distributed
computign to be performed within the
environment. It looks as though the changes
introduced are a java-based equivalent of the LDAS
wrapperAPI (although they do not use MPI). they
use "OCL" protocol for socket based communications
in Java (object communications language(?))
LDAS Hardware:
Continued planning and testing of installation for
LDAS uninterruptable power supply shutdown system.
Debugged configuration problems preventing tcl
programmers from testing on certain linux machines.
Corrected environment for mpi programmers to test
software on LDAS beowulf nodes.
Transferred LDAS passwords and other system information
to Gregory Mendell.
General Computing:
MIT:
Nothing to report.
Livingston:
Received an order of Gateway PCs, and are configuring
them and installing software. We are also re-distributing
some
of the PCs for the use of the summer students and visitors.
We
have also purchased some NEC PCs.
We are in the process of checking our network cabling
to verify
its condition and status, and to determine if we need
additional
capacity.
We have a summer student, Sarah Newman, assisting us for
the next
several months.
Hanford:
Working on expanding the local area network connections.
Gregory M. is working on setting up racks and other items for LDAS.
CIT:
Barbara reworked the MOU page to archive pre-1999 information
onto history
pages. This will be installed on Friday.
Began work on web forms for LSC Research Plans.
Installed another iteration of CostBook web forms.
Lisa B. who is now working with the Sys. Admin group has
been assigned to work
mainly on getting the Wilson House setup cleaned up.
Lisa tested all of the ports in Wilson house. Along with
this is gathering
network performance information.
Installed the extended the Cadence licenses.
Researching a replacement for the PortMaster II modem
access. Has
contacted sales reps from Cisco and 3com and Lucent.
Did Samba testing on the connection to Luna. Jay in particular
is having a
problem with his Samba connections. Updated his NIC driver
to see if that
helps give him more stability.
Downloaded the StarOffice 5.2 binaries. The compiler requires
a shared
library patch. Should have that patch number today.
Made a floor plan of the network ports in Wilson House
to be used for further
testing.
Downloaded and started demo-ing OpenSSH clients for the
PC: putty, pscp
(secure copy) and TTSSH. These are all SSH1 clients so
might not be appropriate
for our environment. The pscp is handy, but not pretty,
little utility.
Suresh Attended Usenix 2000 conference.
Helped SURF students in 40m with their system/appilcation
problem. Larry has
also been resolving a few of the problems with the system
setup and will be
doing more work on it over the next week.
Fixed minor glitches with mail system.
Set up Sun workstation in third floor bridge for SURF student to work on.
Installed ssh version 2 in albireo (cdssol9) in 40m.
A number of procurement issues have been worked on. The
one that has taken up a
great deal of time is the SUN order with the special
discount offer. The new
accounting system at Caltech has a number of problems
one being that it can't
handle a line item of a refund or discount, this has
been worked around along
with a number of related issues dealing with the implimentation
of Oracle at
Caltech and SUN. Gina should have everything finished
and approved by tomorrow
unless something else pops up.
A number of new PC's have been ordered, received and installed
for various areas
of the project.
We had another virus attack and a number of people received
it. However, only a
few were affected by it. Just remember to not open the
attachment and
immediately delete the e-mail and empty the trash bin.
In some cases , depending
on how your e-mail is set up, you may have to go to the
attachment directory and
delete the file from there also. Be sure a virusscan
software pkg. (Norton or
McAfee) is loaded on your PC.
From: bill kells <kells@ligo.caltech.edu>
For this week mostly having to do with LIGO II optics, and
associated systems considerations (~thermal and thermo-elastic noise).
Completed first tests of m-axis sapphire mirror evaluation with Jordan.
Also involved with Kips sub group on how to "relax" ifo beam profiles
to ameliorate Braginsky noise. Back to heavy analysis on the
40m
recycling puzzles.
From: Phil Willems <willems@ligo.caltech.edu>
Fused silica fiber/ribbon research:
-----------------------------------
We are currently refining our ribbon pulling apparatus with an eye to
improving
diameter uniformity, reproducibility, and strength. The strength
of our ribbons
in bending tests averages about 3 GPa, which is adequate, but the more
stringent
tensile tests average only about 400 MPa, which is clearly inadequate.
We are
investigating the source of this difference and looking for remedies.
From: GariLynn Billingsley <Billingsley_G@ligo.caltech.edu>
The first 15 cm Sapphire piece was examined under a bright light. No inclusions were found, there were some small scratches on the OD. The polish on one of the sides was noticeably grey, the polish called out was an "inspection polish" so the part is delivered as specified. This piece was shipped to CSIRO for homogeneity measurement. The second piece which will eventually go through the same process, is due soon.
From: Riccardo DeSalvo <desalvo@ligo.caltech.edu>
We welcome Susha that just joined SAS
Hareem
Changed diameter of frequency tuning disk on GASF F1, finally reached
instability, machining disk for intermediate diameters to drive F1
below
200 mHz and measure Q factors.
Lisa
Started the creep oven and measured first termal transients on blades
and structures.
Measured air to blade temperature delays of the order of 40 minutes.
Temperature stability 0.1, 0.2 degrees p.p..
Brett
Mounted stepper motor driver circuit. Wait for VME board for
integration.
Soy
Assembly of LVDT circuits for creep.
Chenyang
Coiling IP actuators.
Giancarlo
Delivered program to determine blade’s shape analitically. It will
further reduce filter stress levels.
Tatsuo, Akiteru
Measured Dh/DT on monolithic filters.
Measured <0.5 mm/degree at 370 mHz and 1.1 to 3.7 mm/centigrade
at 230
mHz. This last measurement not repetitive, the two values
are
incompatible. Likely the measurement (1 hour total) was too fast,
see
Lisa’s results on delays, need to repeat this measurement.
Kenji, Akiteru, Tatsuo.
Tuned the 1.5 mm MGASF filter at 250 mHz, internal modes of blades
are
obviously lower than the 2 mm one (49 Hz, 206 Hz, 440 Hz) and a peak
at
126 Hz is still to be explained (probably from the test structure)
but
attenuation plateau over 10 Hz at better than 50 dB, likely as good
as
70 dB (limited by the accelerometer sensor noise) was recorded (to
be
confirmed).
Obviously the 49 and 220 Hz resonances now stick higher from the lower
plateau and have become visible again.
From: Sam Richman <srichman@ligo.mit.edu>
Stiff isolation system (Sam Richman, Jamie Rollins)
Jamie has completed a rig for testing blade springs used in the two-stage
prototype. It involves ~200 kg of lead bricks, so now it really feels
like we are doing a true gravitational physics experiment. Measurements
of the spring rate and parasitic modes are now starting. Sam has
been tuning the low-frequency parameters of the position sensor + broadband
seismometer loops.
From: Eric Gustafson <gustaf@fastloki.Stanford.EDU>
Subject: Modulators, Isolators, Mode Cleaners
and Telescopes Telecon
Minutes
Modulators, Isolators, Mode Cleaners and Telescopes
Telecon Minutes
Thursday June 15, 2000
9:00 AM (California Time) - Phone in Number (650) 723-2393
Chair Persons David Tanner and David Reitze
Attendees:UF: Reitze, Tanner, Stanford: Gustafson, CIT: Camp, Sanders, LHO: Ottaway, Fritschel
1. Review of Modulator Work (10 min.) - Reitze
Nothing to report; still waiting on delivery of Leysop large aperture
EOM.
2. Review of Isolator Work (5 Min.) - Reitze
Isolation - Dual crystal birefringent compensating isolator tested
at 100 W powers. We were able to achieve 45 dB isolation. Typically,
commercial isolators give 30-35 dB at low powers. Eric raised the
question of isolation requirements for LIGO II. The consensus is
that it's difficult to assign a requirement.
Thermal lensing - The 60 W laser is working now. The UF group has tested three different bare TGG crystals (Litton, Electro-optics Technology, and IAP homegrown) by measuring the effective focal lengths at high powers. All have comparable absorbances and lensing. Scaling the measurements to > 150W, ~ 50% of the light remains in TEM00 mode, ~45% in TEM20,02 which can be compensated by focus. The remaining light is higher order junk light. These measurements will be verified/refined using the Shack-Hartmann. Peter suggested the possibility of looking at shorter crystals; this may push up the B-field strength beyond reasonable values. Dennis pointed out that heat dissipation may be different in vacuum. Our data from LIGO I tests suggests that it's not too different, but we'll look into it.
3. Review of Mode Cleaner Work (5 Min.) - Tanner
Two baseline designs (12 m and 100 m lengths) are being looked at for
LIGO II. Issues being examined are displacement noise from various
sources (thermal, shot noise, radiation pressure from PSL intensity fluctuations,
jitter-misalignment coupling in the MC), thermal distortions from high
circulating powers, suspension requirements, and physical footprint.
Radiation pressure is the scary noise source at low frequencies (< 100
Hz); we'll definitely need big mirrors. It may place stringent requirements
on the PSL intensity stabilization. Other system trade-offs include
suspension design (do we really need a 3 stage pendulum?) and physical
implementation (a short MC which fits in current HAMs is much cheaper than
a major rework of the LVEA vacuum system). Ray Beausoleil is updating
MELODY to handle triangular cavities. Also of some concern is the
high peak intensities on the mirror coatings. A working IO Reference
Design Study document by the UF group will be ready for prime time late
next week.
4. Review of Telescope Work - Tanner
Nothing significant to worry about or report.
5. Upcoming Deadlines (5 Min.) - Gary Sanders
Gary charged us to come up with the best, cheapest, and most easily
integrated design (with $ costing) in the two months.
6. Open discussions
Meeting adjourned at 12:35 pm EDT before we had time for an open discussion.
For additional information about this report, contact sanders@ligo.caltech.edu