1 / 20

Seismic attenuation chains concept, design and advancement status

Seismic attenuation chains concept, design and advancement status. Riccardo DeSalvo for the KAGRA Seismic group JGW -G1201259. KAGRA-SAS design philosophy. Use only well tested techniques, Take the best from both Virgo and LIGO examples: Virgo ’ s superattenuators/suspensions

olympia-daugherty
Download Presentation

Seismic attenuation chains concept, design and advancement status

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Seismic attenuation chains concept, design and advancement status Riccardo DeSalvo for the KAGRA Seismic group JGW-G1201259 JGW-G1201259 (LIGO-G1200939)

  2. KAGRA-SAS design philosophy • Use only well tested techniques, • Take the best from both Virgo and LIGO examples: • Virgo’s superattenuators/suspensions • LIGO’s OSEMs • Gain from the learned lessons: • Passive instead of inertial damping • Designed for ease of use and fast lock acquisition JGW-G1201259 (LIGO-G1200939)

  3. Modular design Type A Type B Filter zero Standard filter JGW-G1201259 (LIGO-G1200939)

  4. Dual tunnel solution • KAGRA SAS is mounted between two tunnels due to the restrictions of the space reserved for the cryostat • Free and safe access to cryostat and seismic chain! JGW-G1201259 (LIGO-G1200939)

  5. The top filter and IP table • footed on solid rock • Inverted Pendulum table with short legs • Large GAS filter • Easily accessible • No tall structures • Better safety JGW-G1201259 (LIGO-G1200939)

  6. The Type-A KAGRA-SAS Seismic Attenuation System • Amodern, simplified and improved version of the Virgo Superattenuators • Guaranteed performance • Eliminate its main defects • GAS replaces MAS filters • damping stage added at top JGW-G1201259 (LIGO-G1200939)

  7. Thermal Noise Measured Upper Limit Attenuation measurements . courtesy F. Frasconi JGW-G1201259 (LIGO-G1200939)

  8. Improvements over Virgo:damping strategy • Mode damping is vital for easy locking of the interferometer • One extra filter is added at the beginning of the chain it is coupled with a suspended magnet ring to provide passive Eddy current damping for the attenuation chain yaw and other internal modes. JGW-G1201259 (LIGO-G1200939)

  9. Transversal mode damping • seismic noise level of chain’s TM,  with/without Eddy current damping Chain modes IP modes JGW-G1201259 (LIGO-G1200939)

  10. Lowest mode damping • RMS amplitude reduction using shadowmeter on suspension wire JGW-G1201259 (LIGO-G1200939)

  11. Backup damping • active seismic attenuation • Accelerometers onboard similar to TAMA accelerometers. Improved at AEI and NIKHEF • Or feed-forward from ground JGW-G1201259 (LIGO-G1200939)

  12. KAGRA pre-isolator pedigree • The KAGRA SAS pre-isolator was successfully tested in the a-LIGO HAM SAS, further improved at AEI SAS and Virgo-NIKHEF SAS • Performs passively the same functions of all three a-LIGO active stages. JGW-G1201259 (LIGO-G1200939)

  13. Secondary opticsgeneral concept • Used for beam splitter and six recycler mirrors • 1500 mm diameter tank • Easy access to optics and optical bench from one port without entering • Easily Relocatable JGW-G1201259 (LIGO-G1200939)

  14. Attenuation chain • Pre attenuator = inverted pendulum + top filter • Standard filter with Eddy current damper • Bottom filter • Intermediate mass and its recoil mass • Mirror and its recoil mass Design drawings T1100450 and D1200818 JGW-G1201259 (LIGO-G1200939)

  15. The four components of type-B • External structure • Vacuum tank • Attenuation chain • Optical bench Also see G1200806 JGW-G1201259 (LIGO-G1200939)

  16. External structure • Mechanically Independent from noisy vacuum tank • Magnetic feet to satisfy relocation requirements • Also see T1100638 JGW-G1201259 (LIGO-G1200939)

  17. Canned in 2 sub-units for travel and fast installation JGW-G1201259 (LIGO-G1200939)

  18. All 19 standard filters produced, assembled & tested.Stored at Akeno JGW-G1201259 (LIGO-G1200939)

  19. SAS Project advancement • Design/construction (*) six out of eleven top filters to be completed within 2010/2012 budget JGW-G1201259 (LIGO-G1200939)

  20. KAGRA- SAS Project status • 2010/2012 budget • ( ~ 2 M$ including design and manpower) • Completed design of all components • Completed prototypes of all critical components • Built all standard filters (UHV comp. and tested) • Build 6 out of 11 Top filters • 2013/2015 budget (t.b.d.) • Complete construction of all SAS and vacuum tanks JGW-G1201259 (LIGO-G1200939)

More Related