Panel Questions addressed What is the number of noise sources that were discovered between S1 and S2 and between S2 and S3? Question 3 What is the work plan for the Hanford interferometers after S3? What are the plans for pushing identified noise sources down? Question 7 How many of the noise sources that have been identified will not be helped by Advanced LIGO? Question 11 What are the roles of the 11 graduate students that are currently supported by LIGO? Question 14 What is the total number of PhDs associated with LIGO that were granted in the last five years?

6. Noise sources encountered Commissioning philosophy is to get as quickly as possible to the riskiest parts of the detector, e.g. Length and alignment control of long cavities Optical properties of the mirrors Digital control system Operate with the minimum number of subsystems necessary to get initial assessment Then bring on major subsystems, e.g. Full frequency control (common mode) servo Full angular sensing and control (wavefront sensing) system

6. Noise sources encountered Electronics noise ADC noise  analog whitening filters DAC noise  analog dewhitening filters Sensing/dark noise  detect more light Digital suspensions and new coil drivers Noisy analog electronics RFI Frequency noise Common mode servo makes mode cleaner follow common arm as a quiet frequency reference High bandwidth in three nested loops  need 1 MHz bandwidth in PSL loop, 100 kHz bandwidth in MC loop, 20 kHz in CM loop Hybrid digital-analog servo with blended actuation paths Intensity noise Sensing after mode cleaner added frequency noise Dynamic range, saturations, non-linearities

6. Noise sources encountered Acoustic noise and microphonics Beam clipping on limiting apertures Vibrational modes of periscopes Phase noise on input light and at detection ports Angular misalignments 12 degrees of freedom need to be controlled to bring ifo to same DC operating point Alignment sensitivity matrix depends on power in ifo (thermal lensing effects?) Blend wavefront sensing and optical lever damping actuation paths Auxiliary degrees of freedom Sensing noise in Michelson (MICH) and power-recycling cavity (PRC) which sensed at a pick-off port with little light (low sensitivity) Wedged optics in power-recycling cavity  large coupling of 12 Hz bounce mode to longitudinal dof High bandwidth with noisy sensor  BAD news

Progression in Strain Sensitivity L1

L1 during S1

LLO S2 Sensitivity

Scattering reduced by acoustic shielding

3. Work Plan for Hanford after S3 Optical noise (f  200 Hz) Increase laser power Thermal lensing Thermal compensation Increase RF sideband coupling into PRC Increase overlap between Carrier and RF sideband at AS port Acoustic mitigation (60  f  few 100 Hz) Complete REFL port work  frequency noise Auxilliary degrees of freedom (f  100 Hz) Reduce sensing noise by detecting more light at POB Damp vertical mode (at 12 Hz) to reduce bandwidth requirement of PRC and MICH loops Engage correction paths (depends on stability of MICH  AS coupling coefficient)

3. Work Plan for Hanford after S3 Alignment control system (f  50 Hz) Adaptive algorithms for ASC to include Sideband power and arm power scalings Radiation pressure compensation RF phase Wideband control loops to wean off optical lever Beam centering to within 1mm on optics using zoom lenses and fast image processing

3. Work Plan for Hanford after S3 Low noise DACs from FDI have 100x lower noise New AS_I servo to subtract RF signal in “other” quadrature from photocurrent Intensity stabilization External pre-isolation (PEPI) Wideband frequency servo boards Output mode cleaner

3. Summary of post-S3 work First ~6 months after S3 L1 H1 H2 ► Seismic upgrade: HEPI installation & commissioning ► Electronics rack relocation H1 ► New DACs (old DACs to HEPI) ►Thermal compensation trial ► New ASC code ► Wideband WFS control ► Laser power increase ► Output mode cleaner? ► Duty cycle H2 ► Power increase (thermal lens) testing

7. Noise sources not aided by AdLIGO AdLIGO and initial LIGO closely related! Incorporate lessons of initial LIGO into AdLIGO design, and vice versa Examples Detection ports sensitivity to acoustics and microphonics  enclose in vacuum in AdLIGO Frequency noise sensitivity  DC readout scheme Difficulty in obtaining high duty cycle, angular misalignments, auxiliary degrees of freedom  AdLIGO seismic isolation system Seismic remediation at LLO  AdLIGO hydraulic actuator Subtleties of suspension DOF  AdLIGO digital controllers Instability of recycling mirror cavity  AdLIGO thermal compensation system Correction of mirror figure at LHO  AdLIGO thermal compensation system No surprises in initial LIGO to date for which solutions have not been able to be integrated into AdLIGO New ones possible – non-linearities, scattering, charging Will continue to watch for this, and modify AdLIGO as needed

11. Graduate Students in LIGO CALTECH Dan Busby AdLIGO Thermal Noise 2005+ Lisa Goggin 40m RSE Prototype Hareem Tariq AdLIGO Seismic Isolation MIT Rana Adhikari Commissioning and Data Analysis 2004 Stefan Ballmer Joe Betzweiser Commissioning and AdLIGO e2e Lindy Blackburn Data Analysis Shourov Chatterji Thomas Corbitt AdLIGO Quantum Noise and QND Keisuke Goda Commissioning and QND Jamie Rollins Laser Intensity Stabilization (M. Sc.) Lei Zuo Control Systems (Mech. Eng.)

14. Recent Graduates in LIGO/LSC Matt Evans InLIGO Lock Acquisition CIT 2002 Jim Mason Table-top RSE 2000 Shanti Rao AdLIGO Thermal Noise 2003 Brett Bochner FFT Model MIT 1998 Ryan Lawrence AdLIGO Thermal Compensation Julien Sylvestre Data Analysis Tom Delker Table-top dual recycling UFl Dan Shaddock Table-top RSE/DR ANU Bram Slagmolen Thermal noise Andri Gretarsson SYR 2001 Peter Byersdorf Sagnac Ifos STA Osamu Miyakawa 3 m RSE prototype UTOK Kentaro Somiya RSE ifos Gerhardt Heinzel 30 m RSE prototype MPQ And dozens of others …

14. Recent Graduates in LIGO/LSC Calum Torrie Suspension systems GLA Matt Husman Peter Sneddon Thermal noise David Crooks Stefan Traeger Thermal noise and QND HAN Matt Lawrence Laser noise reduction STA Todd Rutherfiord High power lasers And dozens of others, including engineering students, masters students, undergraduates …