1. 1 Cryogenic payload is not a simple system. We need cryostat to test cryogenic payload performance. 1/4 cryostat will be prepared in Kashiwa campus. 1/4 means number of cryocooler, not size. Construction of vacuum chamber is in progress. Final discussion for items inside shields (17 April 2013) 1/4 cryostat

2. 2 Construction of vacuum chamber is in progress. (Jecc Torisha, 1.2 m in diameter, 1.6 m in height)

3. Cooling test of KAGRA cryostat is in progress. 3 We have plans of experiments in Toshiba cooling test of KAGRA cryostat. Experiment 1 : Initial cooling time Experiment 2 : Measurement of shield vibration Experiments in Toshiba cooling test

4. 4 Al hollow spheres (100 mm in diameter) Y. Sakakibara’s small experiment in Kashiwa : 30 mm in diameter Without DLC With DLC Experiment 1 : Initial cooling time Experiments in Toshiba cooling test Sphere with DLC (2 nd cryostat) Sphere with SolBlack (4 th cryostat) Sphere without black coating (1 st cryostat)

5. 5 Dummy payload (hollow masses, 3rd cryostat) Half size Hollow masses (~5 kg) DLC coating Sapphire bulk as dummy mirror S. Koike (100 mm in diameter) Evaluation of emissivity Experiment 1 : Initial cooling time Experiments in Toshiba cooling test

6. 6 Vibration of shield could be problems. Vibration via heat links, Scattered light We must measure the vibration of shield. This measurement is at cryogenic temperature and in vacuum. Luca Naticchioni (Rome) and Dan Chen (ICRR) will measure vertical (2 nd cryostat) and horizontal (3 rd cryostat) vibration of radiation shield of KAGRA in cooling test of Toshiba, respectively. Experiment 2 : Measurement of shield vibration Experiments in Toshiba cooling test

7. 7 All cryocoolers stopped on 15 th of April, 2013. Meeting for summary : 9 th of April at KEK (Discussion is still in progress) Dan Chen and Yusuke Sakakibara (and Kazuhiro Yamamoto) will report Italy-Japan workshop on the 19 th of April. Current status Experiments in Toshiba cooling test

8. 888 Length = 350 mm diameter = 1.8 mm Almost as needed in bKAGRA. Need to check the quality and improvement. T. Uchiyama asked MolTech GmbH (Germany). Sapphire fibers have already come ! Sapphire fibers

9. 9 Ettore Majorana asked IMPEX HighTech GmbH (German company). They made similar fibers (nail heads on the both ends). Sapphire fibers

10. 10 Quality check Q-value Measurement in Glasgow and Jena Y. Sakakibara visited for measurement. Plan for measurement in Rome and ICRR (C. Schwarz and G. Hofman’s visit from Jena to export automatic measurement system. Cryocooler operation started yesterday) Thermal conductivity Measurement in Jena Plan for measurement in Rome and ICRR Strength test Discussion with Glasgow (Thanks for E. Hirose) Sapphire fibers

11. 11 After Y. Sakakibara left …. It is slightly smaller than KAGRA requirement ! Q measurement in Jena Preliminary result Sapphire fibers IMPEX R. Douglas’s poster in LVC meeting (March 2013)

12. 12 It is smaller than KAGRA requirement, but same order of magnitude. Preliminary result Sapphire fibers Thermal conductivity measurement in Jena Moltech C. Schwarz

13. 13 Sapphire fibers Strength test Discussion with Glasgow (4 th of April) Stretch and bend test Some fibers were sent to Glasgow. Crystal structure X ray apparatus in Jena

14. 14 Mechanical loss of coating 14 Discrepancy between Tokyo and Glasgow Tokyo Glasgow K. Yamamoto et al., Physical Review D 74 (2006) 022002. I.W. Martin et al., Classical and Quantum Gravity 27 (2010) 225020.

15. E. Hirose is measuring mechanical loss in ICRR (University of Tokyo). K. Graig (Glasgow) joins measurement (April). Coated sapphire disks were annealed in NAOJ (by K. Waseda). Glasgow group reported the annealing effect on the coating mechanical loss. Construction of the measurement system for KAGRA coating Result is coming soon ! Mechanical loss of coating

16. 16 What is concern ? SEO suggested that the first prioroty is the interface with the other subgroups. MIR : How to suspend mirror Small meeting (Y. Saito, T. Suzuki, K. Yamamoto) on the next week VIS : Connection between room and low temperature Small discussion (R. Takahashi, K. Yamamoto 25 th of Feb.) AOS : Baffle in radiation shield (Discussion every month) DGS and AEL : Budget in 2013