Cryogenic system installation and update on the cryo-payload system for the KAGRA detectorRahul Kumar1, T. Takayuki1, K. Yamamoto2, H. Tanaka2,T. Miyamoto2, T.

Suzuki1, N. Kimura1, T. Kume1 and The Cryogenics GroupHigh Energy Accelerator Research Organisation (KEK) 1, The University of

Tokyo (ICRR) 2, Japan

11th Edoardo Amaldi Conference on Gravitational WavesJune 21 – 26, 2015, Gwangju, South Korea

Outline

• KAGRA project (status talk by R. Flaminio)

• Cryostat installation

• Design status: Cryogenic payload system

• Conclusions

3

Cryostat Installation

Installation video link : https://www.youtube.com/watch?v=6n6nuxA_xlY

4.3 m

2.6 m

4

Cryostat Assembly

4.3m

2.6m

All the cryostats have been installed and assembled.

5

Vacuum Tubes and Tanks Installation

Tests for vacuum leakage ongoing

Beam tubes: φ800mm x12m x 478

Mode cleaner and BS tanks

6

Teething problems Vibration Measurement Results by Seismometer

Seismic vibration at X-end cryostat is expectedlevel, comparable with CLIO site.

In front of water pit where is about 10m fromthe cryostat location, we found excess over 10Hz.

~ 3x10-9

Vertical

Measurement by T. Takayuki

Underground water much more than expected especially during the spring season when snow

starts to melt

4 cryogenic mirrors

X-end

Y-end

Vibration isolation system

Total height 14m

Room temperature

Cryo-duct

Cryogenic payload system

Cryostat housing cryogenic payload

Cryo-payload

Cryo-cooler

Cryo-shield

Laser beam

Cryogenic Payload system

Sapphire Mirror

Recoil Mass

Bottom IM w/ sapphire blades

Sapphire suspension fibers

Upper intermediate mass (IM) w/ moving mass

IM recoil mass and heat link are not shown.

CuBe blades

Moving mass

Platform stage

Marionette

Marionette for control

Sapphire suspensions

• Optimising the overall design

• FEA modelling of TN from the platform stage and intermediate mass

Sapphire suspensionsDesign and TN

discussed yesterday

Metal prototype: lowermost stage

Pitch/roll measurements @ KEKMarionette

CuBe blades

Dummy mirror23 kg

Intermediate mass

• Using dial gauge and laser displacement meter

• Measure displacement by degree of leaning

• Marionette inclined => 3 degrees

Test performed by Takahiro Miyamoto

(MSc student)

Fabrication: Cryogenic payload

Sapphire mass (23 kg) with side cuts for ear attachment

Sapphire ear

Sapphire bladesSapphire fibres

350 mm

Sapphire nail head

10 mm

1st Cryogenic payload system to be

fabricated in 2015-16

Ongoing work (KEK and ICRR)

•Q measurements: sapphire fibres, sapphire blades

•ANSYS modelling to improve/optimize the Cryo-payload design

•Discussions with IMPEX (Germany) and Shinkosha (Japan) for the fabrication of sapphire parts

Conclusions

• KAGRA Tunnel excavation completed: cryostat, beam tubes have been installed

• Underground water an issue!

• Design and testing of the components for cryogenic payload system currently ongoing

• We plan to fabricate the first cryogenic payload system in this FY (2015-16)