1 / 23

Cryogenics for LCGT

Cryogenics for LCGT. Technical Advisory Committee for LCGT 2005.08.23 ICRR. SUZUKI, Toshikazu High Energy Accelerator Research Organization. contents. Achievements of CLIO cryogenics Objects to be cooled and requirements Heat transfer Cryocoolers Design examples of LCGT cryogenics

cricket
Download Presentation

Cryogenics for LCGT

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. Cryogenics for LCGT Technical Advisory Committee for LCGT 2005.08.23 ICRR SUZUKI, Toshikazu High Energy Accelerator Research Organization

  2. contents • Achievements of CLIO cryogenics • Objects to be cooled and requirements • Heat transfer • Cryocoolers • Design examples of LCGT cryogenics • Summary

  3. Achievements of CLIO cryogenicsCooling down • Full operation of cryogenic system with dummy mirror installation. • A small Ohmic heater simulates a laser absorption. • Temperature of cryogenic parts are cooled down to their designed values. (T.Uchiyama , Fig.11 in Chapter 11, Technical Report of LCGT )

  4. Achievements of CLIO cryogenicsCryocooler system with sub-m vibration Cold head -> Cryostat ≈ Seismic background 2nd V.R.Stage -> Heat Link Amplitude ≃ 50 nm

  5. Achievements of CLIO cryogenicsVibration at 300K stage • Red • PT Cryocooler:ON • Vacuum Pump :ON • Blue • PT Cryocooler :OFF • Vaccuum Pump :OFF • Cryocooler operation does not degrade seismic background at 300K stage. (Fig.12 in Chapter 11 ,Technical Report of LCGT) K.Yamamoto

  6. Achievements of CLIO cryogenics • Technology of cryocooler system with small vibration has been established. • Cryocooler system can operate without affecting seismic background. • Design of heat balance on cryogenic system was confirmed. Extend CLIO Cryogenics --> LCGT Cryogenics

  7. Heat generation on the mirror Mirror substrate : Sapphire Suspension rods : Sapphire Safety factor ・ Design q=290 mW T=20 K T.Uchiyama ,Technical Report of LCGT

  8. Heat leaks from 300K to cryogenic parts • Conduction from SAS • Black body radiation from holes • Conduction through support of shields • Scattered Laser light • Conduction through electric cablings • Radiation to shields Heat Link Efficiency Heat Load of Cryocooler (T.Uchiyama, Fig.2 in Chap.11 , Technical Report of LCGT)

  9. Heat flow of LCGT cooling system 8 K 4.2 K (T.Tomaru, Fig.1 in Chap.13, Technical Report of LCGT )

  10. Estimation of heat flow (T.Tomaru, Fig.2 in Chap.13, Technical Report of LCGT )

  11. Heat transfer in cryogenic GW detector • Ultra-high vacuum • Conduction through solid • Compatibility with vibration isolation • Large conductance for heat flow • Small conduction for mechanical vibration • Small mechanical loss for mirror support Mirror Support : large , small mechanical loss, large strength From SPI to Cryocooler : large , small Young’s modulus From SAS to Platform : small , large strength

  12. Material selection:Sapphire • Sapphire is the only candidate for mirror support • Size effect for thin rod (T.Tomaru) (T.Uchiyama) Type of carrier Velocity of the carrier Specific heat Mean free path

  13. Material selection:Pure Al 99.9999 % Al Example of pure Al wire 99.999% Al, 0.15 mm x 735 (T.Tomaru, Fig.7in Chap.13, Tech. Rep. of LCGT) (T.Uchiyama, Fig.2 in Chap.12, Tech. Rep. of LCGT) • Material for heat links • Avoid size effect for our purpose • Inside cryostat -> single-wire • Cryostat-cryocooler -> multi-wire

  14. Material selection:amorphous metal • SAS-Suspension platform • Temperature gradient (300K-14K) • Experience in the cryogenic resonant detector (60Hz)

  15. Intermittent charge Variation of temperature distribution Transportation of liquid Handling of evaporated gas Potential danger in deep tunnel Boiling noise Liquefaction facilities Stationary operation Stable distribution of temperature Electricity and cooling water Maintenance Mechanical vibration Cooling power Why cryocooler Liquefied gas Cryocooler

  16. Typical cryocoolers Cold stage~20 m Cold head~0.2 m/sec2 Cold stage~20 m Cold head~20 m/sec2 (T.Tomaru et al., Cryogenics, 44, ( 2004)309-317)

  17. Cryocooler system for CLIO (T.Tomaru, Fig.3 in Chap.13, Tech. Rep. of LCGT)

  18. Requirements for cryocoolers Heat load for LCGT cooling system Cooling power and numbers of cryocoolers (T.Uchiyama, Table 3 and 4 in Chap.11, Tech. Rep. of LCGT)

  19. Increasing cooling power CLIO PT cryocooler LCGT cryocooler 0.5 W @ 4.2 K 50 W @ 80 K 1 W @ 4.2 K 100 W @ 80 K ◎ Compressor with larger capacity U=pV ○ Increasing nubmers of cryocoolers with current model ☆ Cryocooler with 1W@4.2K already exist but not suitable for VRS type system. Target will be attainable within the extension of current technology.

  20. Design example of LCGT cryostat

  21. Example of cryostat location (T.Uchiyama, Fig.5 in Chap.11, Tech. Rep. LCGT)

  22. Summary of LCGT cryogenics • Fundamental technology of cooling system has been established. • The PT cryocooler system of CLIO with low-level vibration have already satisfied the requirements of LCGT • The way of increasing cooling power is attainable from current technology. • Properties of key materials are known. • Scale up from CLIO to LCGT is available.

  23. Connection of cold head and valve table Vac. Pump Compressor

More Related