Transcript Core Optic Components (COC): Planned/Needed FY07

Technical Progress
Planned/Needed in FY07
Advanced LIGO Program Advisory Panel meeting,
30 November – 1 December 2006, MIT
Dennis Coyne, Caltech
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Technical Progress:
Planned/Needed in FY07

state of development -- advise on triage or prioritization to ensure readiness
Systems (SYS)
Interferometer Sensing & Controls (ISC)
Control & Data Systems (CDS)
incl. Data Acquisition, Diagnostics & Control (DAQ)
Data and Computing Systems (DCS)
Seismic Isolation (SEI)
Suspensions (SUS)
Core Optics Components (COC)
Input Optics (IO)
Auxiliary Optics System (AOS)
Thermal Compensation System (TCS)
Pre-Stabilized Laser (PSL) system
Facility Modifications &
Preparations (FMP)
Installation (INS)
LIGO Advanced System Test Interferometer (LASTI)
40 m Lab Experiment (40m)
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Subsystems without significant start-of-project, readiness concerns:
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PSL – 35W front-end MOPA for enhanced LIGO will be installed 2007
IO – high power component technology & subsystem design well developed; components to
be tested in Enhanced LIGO
AOS –low-risk engineering, with the exception of AOS/Thermal Compensation System (TCS)
Data and Computing Systems (DCS) – design based on off-the-shelf hardware (in the future)
FMP/INS – minimal preparation for contracted items; mostly not schedule critical
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40m – responsive to ISC needs
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Systems:
Planned/Needed FY07 Progress

Conduct a Systems Preliminary Design Review (1st Qtr 2007)
» Effort lags plan
– Risk of improper requirements flowdown – Systems Scientist & Engineer
involved in most subsystem meetings & decisions
– Distraction of key staff -- hiring & setting priorities
Decision: Stable vs Nearly-Unstable Signal &/or Power Recycling Cavities
Modulation scheme & frequencies chosen (ISC)
Definitive optical layout for the Core Optics
Preliminary (but complete) opto-mechanical layout for all LVEA systems
Finalize all generic design & fabrication guidance (EMI/EMC, UHV, QA/QC,
etc.)
» Interface Control Documents established for all subsystems
» Contamination Control Plan/Design (with COC)
» Simulation
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– Demonstrate angular stability at high power
– Sensitivity of optical design to optical figure, thermal lensing
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Likely defer till Final Design Phase (FY08):
» Suspension Point Interferometer (SPI)
» Simulation
– Determine if parametric instability (coupled acoustic & optical modes) are to be
mitigated by COC design (ITM transmission, coating aperture)
– Improved lock acquisition approaches
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Interferometer Sensing & Control (ISC):
Planned/Needed FY07 Progress
 Hold a Design Requirements Review (1st Qtr 2007)
 Preliminary Design progress through 2007 (review late 07 or early 08)
» In-vacuum, suspended Output Mode Cleaner (OMC) and photodection to be
demonstrated
– LASTI testing starts May 2007; currently in preliminary design
» DC read-out and OMC performance in an interferometer
– 40m Lab experiment: non-suspended prototype under test
– Enhanced LIGO: to be installed Nov 2007
» Length, Alignment and modulation
scheme chosen
– Required to definitize the optics layout
& COC parameters (COC polishing
starts CY08)
– Modeling underway
» Lock acquisition scheme
– demonstrated in End-to-End (E2E)
simulation (possibly)
– Demonstrated in 40m experiment
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Control & Data Systems (CDS):
Planned/Needed FY07 Progress

Conduct a Data Acquisition, Networking & Supervisory Control
(DAQ) Requirements Review (early 2007)
 Preliminary Design progress through 2007 (review late 07 or early
08)
» Install & Test at LASTI (PCIX & EPICS architecture):
– FrameBuilder, RealTime Network (Myranet) & Quad Suspension controls
(PCI-X) have been installed & are under test
– Install/test of HAM-SAS prototype controls has begun (to be completed Jan)
– BSC-ISI prototype controls
– OMC Length & Alignment Controls, OMC SUS Controls & antisymmetric
optical port Read-out electronics
– DC Power distribution system
» EMI/EMC and thermal management approach to be defined
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Install & Test at 40m Lab:
» OMC Length & Alignment Controls & Read-out electronics & software
are nearing completion (based on new architecture)
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Concerns:
» QA & QC (including proper & timely definition of requirements)
» Thermal management for front-end systems – liquid cooled?
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Core Optic Components (COC):
Planned/Needed FY07 Progress
 Preliminary Design efforts through 3Q 2007
 ‘Polishing Pathfinder’ RFP
» Achieve Advanced LIGO requirements on full scale optics
(better figure & tighter Radius Of Curvature tolerance)
» Hope to contract 3 polishers soon
 Coating R&D continues to reduce thermal noise &
absorption
» coatings good enough, but improvements help performance
 Prepare production polishing RFP package (ready for
FY2008 funds)
 Concerns:
» Understanding & Controlling loss due to point scatter
– Currently installed test masses indicate 30-40 ppm of scatter loss
– R&D continues to identify source/cause (substrate, coating)
» Polishing Pathfinder is late – COC is a (near) critical path effort
» Single Source for Test Mass Coatings (LMA/Lyon)
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Thermal Compensation System (TCS):
Planned/Needed FY07 Progress
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Thermal compensation strategy is still evolving (conceptual design last Aug)
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Testing
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Compensation plate dimensions changed to improve radiative coupling to the test
mass
Proposed addition of low emissivity coating on the test mass barrel (to mitigate radial
gradients)
Considering removal of compensation plate ring heater
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All of these considerations effect suspension and COC design details
Hartmann sensors at Gin Gin
Initial and Enhanced LIGO (CO2 heating beam)
Ring heater at LASTI (temperature fields only)
Full scale performance via simulation alone
Concern is late development compared to need to finalize the COC optics and
Compensation plate might
Suspension design details
be a –dn/dT material
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external
heating beam
mask
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Ring heater
Seismic Isolation (SEI):
Planned/Needed FY07 Progress
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HAM Isolation
» ISI (baseline, “stiff”) or SAS (alternate, “soft”) Decision (4/2007)
– HAM-ISI (“stiff”) single stage prototype design & revised costing
– HAM-SAS (“soft”) prototype test at LASTI
» HAM prototype fabrication (Enhanced & Advanced LIGO)
– 1st unit ready for install at LLO by Oct
– 2nd & 3rd units ready for install at LHO & LASTI by Dec
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BSC-ISI prototype
» Complete clean assembly & installation
» Performance testing:
– Stand-alone
– With quadruple, ETM suspension (test dynamic coupling, control re-allocation, etc.)
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System Diagnostics & Control Synthesis Tool Development
» Essential for rapid control system tuning after installation
» Stanford’s on-going ETF Technology Demonstration effort supports the control
synthesis
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Concerns:
» HAM-SEI is critical path and development schedule has risk – contractor hired
» LIGO SEI is understaffed – looking for personnel now
» Dual HAM-ISI & HAM-SAS effort may have significant payoff but saps critical
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resources & is divisive – hold to April 2007 decision date
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Suspensions (SUS):
Planned/Needed FY07 Progress
 Suspensions – 11 Types:
Suspension (SUS)
#
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stages chains
# per
IFO
Responsibility
Design
Maturity
R&D
Risk
Final Design Phase
Common ETM & ITM design
"Noise" Prototype @LASTI June
Medium
Chamber
2
Optic
("Payload")
End Test Mass (ETM)
4
2
Input Test Mass (ITM)
4
2
2
Folding Mirror (FM) [combined with ITM]
3
1
2 (H2 only)
started Preliminary Design
Medium
Beamsplitter (BS)
3
1
1
started Preliminary Design
Medium
Recycling Mirrors (RM)
3
1
2
Preliminary Design prototype completed
Low
Input Mode Cleaner (IMC)
3
1
3
ready to begin Final Design
prototype testing completed
Low
IO
Output Mode Cleaner (OMC)
2
1
1
Preliminary Design prototype underway
Emphasis for Enhanced LIGO
Low
ISC
Low
IO
Low
AOS
BSC
HAM
Input Mode Match Telescope (IMMT)
1
1
3
Output Mode Match Telescope (OMMT)
1
1
3
Steering Mirrors
1
1
2
Suspended Photodiodes
1
1
2
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Analog
Elect.
»
Digital
Elect.
AOS
Medium
COC
SUS-UK
AOS
SUS-UK
NA
SUS-US
SUS-US
Low
IO
Low
PSL
IO
SUS-US
NA
Paced by UK Funding
Proceeding ahead of project need dates
Stressing LASTI integrated test plan
HAM Chamber Suspensions (US):
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Thermal
Comp.
BSC Chamber Suspensions (UK):
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derivatives of Initial LIGO Large & Small
Optic Suspensions
SUS
Efforts are delayed by lack of personnel – in hiring mode now
US suspension focus is Output Mode Cleaner (OMC) suspension for ISC and Enhanced
LIGO
Prototyping for FY07 dependent on LASTI integrated test replan
Electrostatic Charging Issues
» R&D to understand charge generation, transfer and mitigation has been slow
» Testing new earthquake stop design intended for Enhanced LIGO use
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LIGO Advanced System Test Interferometer (LASTI):
Planned/Needed FY07 Progress
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LASTI planning has undergone very significant changes over the years to
accommodate HEPI development and late R&D schedules for SUS & SEI
 LASTI oversight committee is charged with advising on a replan
» Does the deployment of adv. LIGO elements into Enhanced LIGO obviate the need
for LASTI system-level, optical-cavity testing? (HAM-SEI, OMC, PSL)?
» Should we consider any system-level testing at LASTI to be risk reduction alone
and not tie to development/fabrication schedules?
Original two test-cavity layout for LASTI
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