1. 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?

2. 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

3. 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

4. 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

5. Progression in Strain SensitivityL1

6. L1 during S1

7. LLO S2 Sensitivity

8. Scattering reduced by acoustic shielding

11. 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)

12. 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

13. 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

14. 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

15. 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

16. 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.)

17. 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 …

18. 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 …