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Development of vibration isolation systems for LCGT VI. K. Yamamoto , R. Takahashi, T. Sekiguchi, T. Uchiyama, H. Ishizaki A , A. Takamori B , R. DeSalvo C , E. Majorana D , LCGT collaboration ICRR, NAO A ,ERI B , Sanio Univ C ., INFN D. 2011 September 18
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Development of vibration isolation systems for LCGT VI K. Yamamoto, R. Takahashi, T. Sekiguchi, T. Uchiyama, H. IshizakiA, A. TakamoriB, R. DeSalvoC, E. MajoranaD, LCGT collaboration ICRR, NAOA,ERIB, Sanio UnivC., INFND 2011 September 18 The meeting of Physical Society of Japan @Hirosaki University, Aomori
And other people join … K. Kuroda, M. Ohashi, S. Miyoki, C. Tokoku, M. Kamiizumi, U. Iwasaki, Y. Sakakibara, T. AkutsuA, T. SuzukiE, N. KimuraE, S. KoikeE, K. TubonoF, Y. AsoF, T. UshibaF, K. ShibataF, N. OhmaeG, K. SomiyaH ICRR, NAOA,ERIB, Sanio UnivC., INFND, KEKE , Dept. Phys.,Univ. TokyoF , Dept. Appl.Phys., Univ. TokyoG , TITechH
0. Abstract Cryogenic part (cryogenic payload) of seismic isolation system for LCGT project Room temperature part has already reported by R. Takahashi.
Contents • Introduction • Issues • Current status • Summary • Future work
1. Introduction LCGT (Large-scale Cryogenic Gravitational Wave Telescope) 2nd generation interferometric detector in Japan Cryogenic system : One of key features of LCGT project Reduction of thermal noise, thermal lens, and parametric instability K. Yamamoto, Journal of Cryogenics and Superconductivity Society of Japan 46 (2011) 426 (in Japanese).
1. Introduction Vibration Isolation (Type A) Cryostat Cryogenic mirror 6
1. Introduction Shield (8K) Sapphire fiber Sapphire mirror (20K)
1. Introduction Schedule of LCGT iLCGT (room temperature) ~2014.9 bLCGT (cryogenic temperature) 2014.10~ Cryostat installation in ICRR (Kashiwa) ~2013.3 (Check of cryostat system) Check of cryogenic payload in ICRR Design of cryogenic payload ~ 2012.3
2. Issues (1)How to assemble Details of construction, clean room …. (2)Strength Tensile strength, development of clamp, … (3)Control system Actuators (what and where), resonant mode (frequency and Q)
2. Issues (4)Cooling Temperature of mirror, initial cooling time, heat resistance … (5)Noise Thermal noise, vibration via heat links …
3. Current status (1)Thermal simulation for cooling Collaboration with Rome University Astroparticle Physics 35(2011)67. Thermal simulation for Einstein Telescope (3rd generation in Europe) cryogenic payload Cross check
3. Current status (1)Thermal simulation for cooling S. Koike (KEK) tries simulation with same model using ANSYS. Calculation and discussion are in progress … 1/2モデル 4K Φ1mm Cu wire ミラー中心に 直径35mmの ビームがあたる 0.6m Siミラー
3. Current status (1)Thermal simulation for cooling Initial cooling time simulation (Y. Sakakibara) Intermediate mass Platform Mirror Shield Radiation is effective.
3. Current status (1)Thermal simulation for cooling Initial cooling time simulation (Y. Sakakibara) DLC (Sakakibara’s talk) on surface of masses (except for mirror) in payload and shield Shield DLC enhances radiation effect. 14
3. Current status (2) Monolithic sapphire mirror suspension Low mechanical loss, high thermal conductivity Small thermal noise, effective cooling Connection between mirror and fiber If fibers are glued to mirror, there are some problems in process of polish and coating for mirror and in the case of break of fibers.
3. Current status (2)Monolithic sapphire mirror suspension Virgo+
3. Current status (2)Monolithic sapphire mirror suspension Part on end of fiber One company can provide it (Uchiyama). Uchiyama asks another company.
3. Current status (2)Monolithic sapphire mirror suspension Part on surface of mirror Bonding Candidate : Surface-Activated room-temperature Bonding(Ohmae), Ceramic adhesion, Diffusion bonding, Hydroxide-catalysis bonding Measurement of strength and thermal resistance in KEK (T. Ushiba, K. Shibata, T. Suzuki)
3. Current status (2)Monolithic sapphire mirror suspension Part on surface of mirror (T. Ushiba, K. Shibata, T. Suzuki)
3. Current status (2)Monolithic sapphire mirror suspension Part on surface of mirror (T. Suzuki)
3. Current status (3)Noise Angular fluctuation by external vibration (via heat link) : T. Sekiguchi’s talk Thermal noise : K. Somiya’s talk
4. Summary Cryogenic payload : One of key features of LCGT project Cryogenic part of seismic isolation system Cryostat installation in ICRR (Kashiwa) ~2013.3 (Check of cryostat system) Check of cryogenic payload in ICRR Preparation is in progress. (1)Thermal simulation (2)Sapphire fiber-mirror connection (3)Simulation of effect of external vibration (with heat link) (4)Thermal noise
5. Future work (1)How to assemble Details of construction, clean room …. (2)Control system Actuators (what and where), resonant mode (frequency and Q)