LIGO-G06xxxx-00-M Technical Progress Planned/Needed in FY07 Advanced LIGO Program Advisory Panel meeting, 30 November – 1 December 2006, MIT Dennis Coyne, Caltech

LIGO-G06xxxx-00-M 2 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) Subsystems without significant start-of-project, readiness concerns: » 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 » 40m – responsive to ISC needs

LIGO-G06xxxx-00-M 3 Systems: Planned/Needed FY07 Progress Conduct a Systems Preliminary Design Review (1 st 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 –Demonstrate angular stability at high power –Sensitivity of optical design to optical figure, thermal lensing 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

LIGO-G06xxxx-00-M 4 Interferometer Sensing & Control (ISC): Planned/Needed FY07 Progress Hold a Design Requirements Review (1 st 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

LIGO-G06xxxx-00-M 5 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 Install & Test at 40m Lab: » OMC Length & Alignment Controls & Read-out electronics & software are nearing completion (based on new architecture) Concerns: » QA & QC (including proper & timely definition of requirements) » Thermal management for front-end systems – liquid cooled?

LIGO-G06xxxx-00-M 6 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 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)

LIGO-G06xxxx-00-M 7 Thermal Compensation System (TCS): Planned/Needed FY07 Progress Thermal compensation strategy is still evolving (conceptual design last Aug) » 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 » … » All of these considerations effect suspension and COC design details Testing » 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 Suspension design details external heating beam Ring heater mask Compensation plate might be a –dn/dT material

LIGO-G06xxxx-00-M 8 Seismic Isolation (SEI): Planned/Needed FY07 Progress 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) –1 st unit ready for install at LLO by Oct –2 nd & 3 rd units ready for install at LHO & LASTI by Dec BSC-ISI prototype » Complete clean assembly & installation » Performance testing: –Stand-alone –With quadruple, ETM suspension (test dynamic coupling, control re-allocation, etc.) 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 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 resources & is divisive – hold to April 2007 decision date

LIGO-G06xxxx-00-M 9 Suspensions (SUS): Planned/Needed FY07 Progress Suspensions – 11 Types: BSC Chamber Suspensions (UK): » Paced by UK Funding » Proceeding ahead of project need dates » Stressing LASTI integrated test plan HAM Chamber Suspensions (US): » 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

LIGO-G06xxxx-00-M 10 LIGO Advanced System Test Interferometer (LASTI): Planned/Needed FY07 Progress 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