Design and fabrication status of RIKEN SC-Linac cryomodule K. - - PowerPoint PPT Presentation

• K. Ozeki, O. Kamigaito, H. Okuno, N. Sakamoto, K. Suda, Y. Watanabe, K. Yamada

RIKEN Nishina Center

• E. Kako, H. Nakai, K. Umemori

KEK

Design and fabrication status of RIKEN SC-Linac cryomodule

• 1. Overview of RIKEN SC-Linac cryomodule
• 2. Magnetic characteristics

NC → SC, SC → NC Performance of magnetic shield for RT at cryogenic temperature

• Feb. 21st, 2017, WG-4

• 1. Overview of RIKEN SC-Linac cryomodule

Prototype: cryomodule which can mount two QWRs

(tentatively, one QWR and one dummy cavity will be installed) Vacuum vessel

• Vacuum of QWR is isolated

Magnetic shield

• 2 mmt permalloy
• Enfolding QWR and He jacket
• Mark: 20 mG @ top part of QWR

Thermal shield

• 2 mmt Al
• 77-K GM cryocooler CH-100LT (SHI)

~100 W@ 40 K (50 Hz)

Frequency tuner

• Adjustment of gap length of QWR

by distorting QWR in beam axial direction

(MHI-MS, PCT/JP2016/54710, Feb. 18, JP Patent P5985011, 2016)

QWR He jacket Helium buffer tank Dummy cavity Power coupler

• Disk-type double vacuum windows

(40 K / RT)

• Assumed Max. RF power: 10 kW
• K. Ozeki et al., LINAC16, TUPLR061

• 1. Overview of RIKEN SC-Linac cryomodule

Prototype: cryomodule which can mount two QWRs

(tentatively, one QWR and one dummy cavity will be installed) Vacuum vessel

• Vacuum of QWR is isolated

Magnetic shield

• 2 mmt permalloy
• Enfolding QWR and He jacket
• Mark: 20 mG @ top part of QWR

Thermal shield

• 2 mmt Al
• 77-K GM cryocooler CH-100LT (SHI)

~100 W@ 40 K (50 Hz)

Frequency tuner

• Adjustment of gap length of QWR

by distorting QWR in beam axial direction

(MHI-MS, PCT/JP2016/54710, Feb. 18, JP Patent P5985011, 2016)

QWR He jacket Helium buffer tank Dummy cavity Power coupler

• Disk-type double vacuum windows

(40 K / RT)

• Assumed Max. RF power: 10 kW
• K. Ozeki et al., LINAC16, TUPLR061

For Actual cryomodules, installation in He jacket is planned Performance test of magnetic shield (permalloy) for RT at cryogenic temperature

• 1. Overview of RIKEN SC-Linac cryomodule
• Feb. 17th 10:35

Assembly of each component into cryomodule is now in progress Cooling test: next month

VTs at KEK

1)

• Jun. 30th, 2016

2)

• Sep. 7th, 2016

3)

• Oct. 20th, 2016
• One fluxgate installed

4)

• Feb. 1st, 2017
• Performance test of magnetic shield for RT at cryogenic temperature
• Two fluxgates installed
• 2. Magnetic characteristics

VT3 on Oct. 20th, 2016

• One fluxgate installed

Cryostat QWR Magnetic shield (RT)

Stem Temperature reference points Si-diode (accuracy: ±0.25 K) Stem root Outer torus Side port

(attached to blank flange)

Lower welded spot

(between bottom pan and trunk) General setup

Magnetic field in vertical direction

VT3 on Oct. 20th, 2016

Si-diode Fluxgate

VT3 on Oct. 20th, 2016

Si-diode Fluxgate NC → SC

VT3 on Oct. 20th, 2016

Si-diode Fluxgate NC → SC Radiation shield was set on the pit: ΔH ~ 1 mG

VT3 on Oct. 20th, 2016

Si-diode Fluxgate NC → SC Q-measurement: no influence on H Radiation shield was set on the pit: ΔH ~ 1 mG

VT3 on Oct. 20th, 2016

Si-diode Fluxgate NC → SC SC → NC Q-measurement: no influence on H Radiation shield was set on the pit: ΔH ~ 1 mG

VT3 on Oct. 20th, 2016

Si-diode Fluxgate NC → SC SC → NC Q-measurement: no influence on H Radiation shield was set on the pit: ΔH ~ 1 mG

ΔH ~ 1.5 mG

VT3 on Oct. 20th, 2016

Dotted lines: temperature got lower / higher than 9.2 K at each point (accuracy: ±0.25 K) H got higher until the trunk of QWR partially transited from NC to SC. Then, H got lower to the level lower than initial H.

NC → SC SC → NC

SC NC NC SC

FG

H jumped up when the lower part of QWR transited from SC to NC.

VT4 on Feb. 1st, 2017

• Performance test of magnetic shield for RT at cryogenic temperature
• Two fluxgates installed

Cryostat QWR He jacket Magnetic shield (RT)

General setup

+ Magnetic shield (Cryo-temp.)

Temperature reference points Si-diode (accuracy: ±0.25 K) Stem root Side port

(attached to blank flange)

Coupler port Outer torus Stem Magnetic field in vertical direction Cavity trunk

Directly beneath

• pening of shield

→ not fully shielded

VT4 on Feb. 1st, 2017

Offset?

Si-diode Fluxgate Q-measurement: no influence on H Radiation shield was set on the pit: very small shift in H NC → SC SC → NC

VT4 on Feb. 1st, 2017

No apparent behavior Dotted lines: temperature got lower / higher than 9.2 K at each point (accuracy: ±0.25 K)

NC → SC SC → NC

NC SC SC NC

FGs

H at both positions showed similar tendency as VT3

VT4 on Feb. 1st, 2017

Performance shift of permalloy for RT (OHTAMA) at cryogenic temperature

• No problems in using permalloy for RT at cryogenic temperature
• Discrepancy in H between before and after VT

(Seems to be attributed to the element other than permalloy ← cf: VT3)

FG-inner FG-outer

Summary

• Present status of cryostat
• Assembly of QWR and other components into one cryomodule

is now in progress.

• Cooling test will be performed in next month.
• Magnetic characteristics
• H around top of QWR were measured.

NC → SC: H gets higher transiently, and then gets lower than initial H. SC → NC: jump up in H / no apparent behavior (unclear ?) Discrepancy in H between before and after VT.

• Performance test of permalloy for RT
• Permalloy for RT seems to be able to be used at cryogenic temperature

without any problems.