1 BROOKHAVEN SCIENCE ASSOCIATES

NSLS-II Insertion Device R&Ds

Toshi Tanabe

George Rakowsky, John Skaritka and Susila Ramamoorthy

NSLS-II Experimental Facilities Advisory Committee (EFAC)

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Outline

1) Cryo-Permanent Magnet Undulator (CPMU) New Magnet / Pole Materials Cold Measurement System New Gap Separation Mechanism

2) In-vacuum Elliptically Polarized Undulator (IVEPU)3) Superconducting Insertion Devices

EPU High Temperature Superconductor (HTS)

4) Cold Gas Refrigeration System5) International Collaborations6) Undulator Laboratory in Bldg. 832

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IVU

Remanence Coercivity

1) CPMU

• Cryo-Permanent Magnet Undulator (Hara, et. al, 2004)• Simple Concept: NdFeB has a negative thermal coefficient of remanent field (Br) [-0.1 % /

K@20ºC], and of intrinsic coercivity (Hcj) [-0.5% / K@20ºC ]• PrFeB (53CR at NEOMAX) shows no “spin canting” at the lower temperature. However,

it does not have high enough coercivity at the high temperature needed for baking.

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New Materials

•W. Swift and M. Mathur

IEEE Trans. Mag. Vol.10, No.2 (1974)

•Bakable PrFeB Magnet• High Hcj type which can withstand the baking temperature (>100 °C)•Get manufacturer/university with production capability involved

•Crystalized Dysprosium Pole• Very high saturation flux density ~ 3.5T

Vanadium permendur ~ 2.3TSoft iron ~ 2.1T

•A few vendors identified•International collaboration subject

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Cold Measurement System

•Cold In-Situ Field MeasurementIn-vacuum mapper with Hall probe. The postion accuracy is maintained by laser tracker and piezo controller.

•In-vacuum streched wire / pulse wire system are

also in consideration

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New In-vacuum Gap Separation Mechanism

Linear motors drive the outer cage.

Vacuum chamber

Rail

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2) In-Vacuum EPUs

• Out-of-vacuum Device (Gmag~10mm)• Apple-II : bigger tuning range, simpler structure• HiSOR EPU: easier shimming and more benign field profile

•Apple-II

•HiSOR

•In-vacuum Helical Undulator at SP8

• In-vacuum Device (Gmag~7mm)

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3) Superconducting Insertion Devices

• Low Temperature Superconducting Undulator• Different techniques are being tested all over the world• Need more R&Ds such as thermal intercept designs and lead design, etc. to

achieve stable operations in a ring

• Superconductor EPUs• Various designs have been proposed• Available only after the development for a linear device is established

• High Temperature SC Device• Depends on the conductor development• New type such as coated conductor and thin film available More design flexibility• Once the conductor exceeds the necessary performance level, it will be very

promising candidates for future IDs

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SC-EPUs and a HTS Undulator

Sasaki Snake

S. Chouhan

Rossmanith

HTSU by T.Tanabe

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4) Cold Gas Refrigeration System

• Use of LHe creates many safety issues to deal with.

• Closed circuit He refrigerator alleviates these problems.

• LHe plant may not be available in the vicinity of the ID.

• Needs higher capacity and more reliability for NSLS-II devices (CPMUs and SCUs)

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Schedule

2007 2008 2009 20112010 2012

1st user beam

New Materials

Cold Measurement

IVEPU

International Collaborations

Gas Refrigerator

SCUs

Undulator Lab

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Summary

• Cold measurement system is essential for the CPMU baseline design• New in-vacuum gap separation mechanism• New material R&Ds for further enhancement of the CPMU performance

• In-vacuum EPU design will be a challenge, but it shares the many development aspects with in-vacuum gap separation mechanism.

• SCU R&Ds• Low temperature SCUs still require R&Ds• SC-EPU will be available once the technology for linear devices matures• HTS versions are promising candidates in the future

• Circulating He gas cooling system needs to be developed • International Collaborations • Undulator Laboratory in Bldg. 832