Advanced LIGO Management
Advanced LIGO Systems
Dennis Coyne <coyne@ligo.caltech.edu>, Peter Fritschel <pf@ligo.mit.edu>, Calum Torrie<ctorrie@ligo.caltech.edu>
AdL Project-Funded Activities
Design Reviews:
For a list of reviews, see the main AdL wiki page
- Participated in HEPI phase 2 procurement readiness review
Procurement Reviews:
- Reviewed and revised the technical input to the HEPI housing & crossbeam foot RFQs
- Reviewed and revised the technical input to the FMP assembly cleanrooom RFQ. Calculated illumination levels.
Technical Review Board (TRB):
see the TRB log
Vacuum Review Board (VRB):
- Held a meeting with safety and lab staff to explain new viewport safety prototcols and implications.
Configuration Control:
Design:
- Working on analysis to establish requirements for passive dynamic damper additions to the test masses as means of increasing acoustic mode damping without compromising thermal noise (as a potential means of suppressing potential parametric instabilities)
- One candidate damper type is an eddy-current damper. Made back-of-the-envelope estimate for such a design, which showed it to be not a very feasible approach; the amount of damping we're after appears to require relatively large amounts/volume of eddy current dampers. Piezoelectric dampers still look quite feasible.
- Continued work on developing an Ansys finite element analysis of the modal strain energies for use in analyzing the effect of inhomogeneous losses (e.g. due to bonded ears and dynamic dampers for PI control)
- Evaluated the effect of the noise performance of the latest BOSEMs. The original BOSEM units had a factor of 3 lower noise at 1 Hz. The reason for the increase was explored by the UB group but no cause was discovered. The conclusion is that while unfortunate that the sensors aren't as quiet as the prototype unit, their performance is acceptable given that production must start imminently.
- Continued to review/establish revised requirements for the HSTS based on the stable recycling cavity design.
Interfaces:
Modeling and Simulation
Facilities Modifications and Preparations
From: John Worden worden_j@ligo-wa.caltech.edu
Nothing to report this week.
Seismic Isolation
From: Ken Mason kmason@ligo.mit.edu
HAM Crossbeam Design
Sending final drawings for LASTI prototype Crossbeams to machine shop on Friday. Still working on remaining details: L-4C clamps, Support Tube clamps, HEPI Caging assemblies, etc. ~ Andy S.
BSC ISI Design
Making further changes to the AdLIGO BSC LARGE actuator assembly models so that these can be tested at LASTI with fewer changed pieces. e.g. designing some adapter plates so that we can try the design changes on the actuator brackets without changing the large, expensive stage 0 post and bridge that these brackets will ultimately attach to. Hope to be making drawings for these models by next week so that these prototype parts can be quoted then ordered before the end of August.
The SMALL actuator assemblies are stalled at the concept model stage--- without the models from PSI for the small actuators themselves the surrounding brackets can't be dimensioned or have holes added, etc. Still in contact with PSI about getting these small actuators moving. ~Stephany F.
SEI Project Activities
Quotes for the HEPI actuators are due today. ~Ken M.
Suspensions
From Janeen Romie and Norna Robertson
(romie_j@ligo-la.caltech.edu, nroberts@ligo.caltech.edu)
*Operations Work *
HAM Suspensions for Advanced & Enhanced LIGO
OMC. The LHO OMC SUS team has made transfer function measurements (posted on the LHO elog) with the metal bench, and these compare well with the MATLAB model. They have now installed the the ISC glass bench and after aligning will take more transfer functions to check everything OK before installation.
Large Triple prototype. We are starting to receive quotes for the large triple blade and wire clamps, needed to characterize the blades. We hope to initiate procurement this week. The drawing tree and parts list are complete. A few parts still need drawings and most need some changes. There is still some work to be done on EQ stop design for the back faces of the intermediate and test masses. We are also considering using cam-type OSEM adjustment fixtures ( similar to those developed for the BOSEMs).
Small triple. We are working on further preliminary design review documentation.
BSC Suspensions for Advanced LIGO
Work continue towards the monolithic build at LASTI now scheduled for September.
Brett Shapiro has updated his document on quad balancing and alignment procedure and circulated for comments.
Doug Cook is researching a device to measure the gap between the ETM/ITM and the reaction mass.
*Project-funded activities*
Work has begun on the RFQ for the SEI and SUS mechanical test stands for the sites. Ken Mason has finished updating the drawings and Betsy has begun organizing the statement of work. We need one BSC-style mechanical test stand for the quad training at LLO in November. The rest of the test stands (quantity 5 total) are not needed until next year.
Work has begun on OSEM value engineering. Focus is on whether the head/former needs to be plated alumina, or whether it can be changed to metal. Also, focusing on whether the components should be changed to the LED & photodiode that the Birmingham OSEM use. A number of other issues have been identified for value analysis.
Work has begun on organizing the RFQ for the quad production assembly tooling. We are still awaiting RAL updates of the top stage tooling, which is scheduled to be completed this week.
Core Optics
From: GariLynn Billingsley Billingsley_G@ligo.caltech.edu
Project
Heraeus and Corning orders have gone out, both are under review at the vendors, we expect signature this month.
We are planning to release documents for final design review in the coming week.
Development
We have fairly conclusive evidence that the highest grade fused silica from Corning contains inclusions, too small for their inspection to capture, that contribute to high scattering, up to 2000ppm in spots. While that material may be used for transmitting control signals we recommend that it not be used in loss sensitive applications, ie. in transmission, as part of a resonant cavity, or in transmission in a loss sensitive beam train.
Until formally written, the results can be found here: http://www.ligo.caltech.edu/%7Elzhang/esw03/esw03_ars_sum_2.pdf This is a summary of data taken on a septum window Corning grade 0AA. As a system check we measured a 1" piece of the same material and found it to be reasonable. Other zones in the septum window also measured at expected values. In light of the upcoming Advanced LIGO IOO procurements, a piece of Heraeus 311 SV (40m BS spare) T080185-00 (currently in DCC out.) We were only able to measure a 5mm x 40mm line, but found it to be uniform and low.
The tooling and compensation plate for LASTI are at Navitar for gold ESD coating and barrel coating. Their quoted delivery time is four weeks from this point.
QED has finished one iteration of MRF on the re-finished pathfinder. They have their surface measurement IFO out for repair, but are not projecting a schedule slip.
Tinsley pathfinder has been delivered from Coastline to ASML, it is currently in soak for initial metrology. First look puts the ROC very close to the desired finish, this means little removal of material. Quite encouraging. The Tinsley metrology review is scheduled for August 21 at Tinsley. Tinsley is currently projecting a 11 day slip.
We have approval to go ahead with a coating experiment where three different polish techniques are coated in the same run. We hope this will shed light on the contribution of polish to scatter.
Auxiliary Optics
From: Michael Smith smith@ligo.caltech.edu
ADLIGO
Work under Project budget
Work under Operations budget
SLC
Mike has revised the concept for baffling of the wide angle scattered light from the ITM and ETM. He proposes a cylindrical baffle close to the COC HR surface and against the Arm Cavity back surface. Without the cylinder in place, the wide angle scattered light onto the BSC chamber and manifold walls, assuming 10 ppm Lambertian scattering loss from the COC surface, exceeds the AOS requirement.
ADLIGO
OPTLEV
Tara, Giovanni, and Zach are continuing to refine their intensity noise measurements of a free-space HeNe beam on a benchtop hitting a quad photodiode.
Robert Schofield is continuing to measure the angular noise characteristics of the LVEA floor and the optical lever piers at LHO.
ETM TEL SUS
Virginio has a preliminary model for the ETM Telescope Suspension, using the masses and moments of inertia given him by Chris.
ELIGO
SLC
Luke completed the installation of the HAM5 baffle at LHO.
Ken completed the installation of both manifold baffles at LHO. He is revising the installation procedure slightly and will communicate that to Gary at LLO.
The Staff at LLO installed the ETM baffles.
Input Optics
ELIGO Commissioning:
Measured FSS AOM double pass diffraction efficiency (61%). Completed FSS beam path.
Reference cavity moved to the new location on the PSL table and locked again.
Started optimizing reference cavity visibility (75%). - Antonio
Preparing for LLO IO vent - Kate
Modulator preparatory work and PSL work - Volker
Advanced LIGO:
We have been looking at the beam splitter flatness and allowable tolerance in the recycling cavity - Muzammil.
A brief study can be found at:
http://lhocds.ligo-wa.caltech.edu:8000/advligo/Recycling_Cavity_Geometry?action=AttachFile&do=get&target=flatnessBS.pdf
Finished aligo mach-zehnder EOM design, finishing aligo in vac-mirror blank drawings - Luke
Prestabilized Laser
From: Peter King pking@ligo.caltech.edu
Operations
==========
In talking with an engineer at Ophir about their L50A-SH calorimeter,
they mentioned that the calorimeter is not meant to be exposed to a high
power laser beam for long periods of time, ie overnight. The accuracy of
the calorimeter falls as the temperature of the calorimeter increases
beyond 75 degC. Typically a stable reading is achieved after 2 minutes.
Project
=======
Another draft of the preliminary design document was released amongst
the working group. We are still aiming for a mid-August release of the
final version.
Some investigation is being carried to figure out why the 4k laser at LHO
tripped out. Whether the chiller tripped and caused the laser to go, or
vice versa. One scenario raised by Christian Veltkamp (LZH) is that the
mains voltage dipped below some level causing the NPRO power supply to go
out, which turn cascaded to the 35-W laser going. The jury is still out.
CDS
From: Rolf Bork rolf@ligo.caltech.edu
- The majority of DAQ PDR documents have been posted to the AdvLigo CDS Wiki. One more remains to be posted, the Software Development Plan, which Vern should have done soon. Some comments/questions starting to come in from the review committee and others.
- More work on the ELigo DAQ system installed at LHO, which employs the basic designs proposed for AdvLigo. Primary focus this week was to get all of the GDS TP/EXC working through the new NDS servers. This now all seems to work, with proper connections to DTT and Dataviewer. Tomorrow, the initial Ligo FrameBuilder (running in parallel with the new system) will get updated software such that both old and new DAQ can get data properly from the new ISI/OMC computers (byte swapping issue between existing Solaris FrameBuilder and new x86 based systems).
- Timing: Work continues on the slave modules, with hardware/software being added to provide the dual tone generator.
- Continuing to design/order components for the 40m lab upgrade as the AdvLigo controls prototype.
- Adding new features to the realtime code generator in support of various ELigo/AdvLigo application development activities:
- Ability to read a separate coefficient file for FIR filters (used in HEPI/ISI).
- Ability to turn on/off filters within a filter module from within the user application (previously just thru EPICS).
- Bit to word and word to bit parts to help reduce the user logic necessary to drive binary in/out modules and the new filter controls.
- Device driver to interface the new 32bit binary output module.