1. Sapphire Test Masses ACIGA/UWA High lights of research at UWA Alternative approach to suspensions High power test facility Cryogenic applications Mark Baker*, Fetah Benabid*, David Blair Ju Li Darren Paget Mitsuru Taniwaki* Colin Taylor LIGO-G010166-00-Z

2. Summary of work in UWA (ACIGA) on Sapphire in collaboration with LIGO: B. Barish, S. Witcomb, D. Reitze, A. Alexandrovski VIRGO: J. Mackowski, A. Brillet, C. Man, F. Bondu, F. Cleva, V. Loriette, C. Boccara

3. History of CSI Whiteand Hemex-Ultra sapphire samples

4. Photothermal Absorption measurement results

5. Absorption Map CSI Standard- #A (plan z=10mm) Xray-irradiated spot Max=55.6ppm/cm min=37ppm/cm aver=45.2 ppm/cm STDdev=3.2

6. Annealing Effect on the Absorption in the UV Range (F centers range)

7. Annealing Effect on the Absorption in the IR Range

8. Birefringence Phase Retardation (degree/ 10cm) Contour Plot of Sapphire Hemex

9. Rayleigh Scattering measurements set-up CCD Ammeter Calibrated photo-detector Laser Data treatment   Sample D D:pupil.  : angle of observation  : collection solid angle V: scattering volume V=d.S

10. Rayleigh Scattering Measurement of Different Sapphire Samples

11. Microcantilever suspension study  Q cantilever ~ 3  10 5  Internal mode of cantilever control  Q sapphire ~ 5  10 7  High pressure contact (plastic deformation) to achieve low loss

12. Internal Q of sapphire

13. The Loss of Test Mass due to the Coupling to the Internal Resonances of Supporting structure

14. Test of monolithic Nb pendulum Annealed & etched flexure 1mm  10mm  60  m Material Q ~2  10 5 Pendulum Q ~ 3  10 7 (3.4 kg, pressure corrected)

15. Ring down of a Nb monolithic pendulum Material Q-factor Q 0 = 2 x 10 5 (gas damping corrected)

16. Dovetail Suspension Tensile equivalent to microcantilever Low loss flexure included Low mass reduces cantilever loss contribution --predicted Q int >10 8 Modular easily replaceable suspension element Exceptional cryogenic performance predicted Need to confirm sapphire Q after cutting

18. 2001 program on suspension: measure internal mode Q of sapphire with Nb flexure suspension Configuration 1 Suspension losses minimised --coupling factor:  0.1~0.3 Dovetail groove near stress antinode --possible Q-degradation Note: dovetail groove is very small cf, Braginsky’s sapphire bar with horns excitation

19. Configuration 2 Suspension loss maximised --coupling factor  =1 Low stress at dovetail joint

20. Cryogenic Applications of Dovetail Flexure Thermal conductivity of niobium at 10K: 90Wm -1 K -1 Expected thermal resistance: ~ 10K/W Niobium is an exceptional material for high thermal conductivity isolation and suspension stages

21. ACIGA High Power Test Facility Research Program 2001Implement 10m mode cleaner Low power evaluation of isolator/suspension pairs  Low residual motion isolators with pre-isolation  Niobium flexure suspensions 2002Adelaide University 5-10W laser. PR mirror + South Arm input mirror Baseline data:  Lock acquisition  Thermal lensing  Optical degradation 200380m high power test cavity 100W Adelaide University laser Power recycling cavity + 80m arm cavity  Lock acquisition under high radiation pressure  Thermal lensing  Optical degradation 2004 East arm cavity -2005Implement interferometer for high power noise evaluation

22. High Power Testing Facility at Gingin, WA