NSLS-II Insertion Device R&Ds

1. NSLS-II Insertion Device R&Ds Toshi Tanabe George Rakowsky, John Skaritka and Susila Ramamoorthy NSLS-II Experimental Facilities Advisory Committee (EFAC)

2. Outline • Cryo-Permanent Magnet Undulator (CPMU) • New Magnet / Pole Materials • Cold Measurement System • New Gap Separation Mechanism • In-vacuum Elliptically Polarized Undulator (IVEPU) • Superconducting Insertion Devices • EPU • High Temperature Superconductor (HTS) • Cold Gas Refrigeration System • International Collaborations • Undulator Laboratory in Bldg. 832

3. 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. IVU Coercivity Remanence

4. New Materials • 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 ~ 2.3T • Soft iron ~ 2.1T • A few vendors identified • International collaboration subject • W. Swift and M. Mathur IEEE Trans. Mag. Vol.10, No.2 (1974)

5. Cold Measurement System Cold In-Situ Field Measurement In-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

6. New In-vacuum Gap Separation Mechanism Linear motors drive the outer cage. Vacuum chamber Rail

7. 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 • In-vacuum Device (Gmag~7mm) Apple-II HiSOR In-vacuum Helical Undulator at SP8

8. 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

9. SC-EPUs and a HTS Undulator HTSU by T.Tanabe S. Chouhan Rossmanith Sasaki Snake

10. 4) Cold Gas Refrigeration System • Use of LHe creates many safety issues to deal with. • LHe plant may not be available in the vicinity of the ID. • Closed circuit He refrigerator alleviates these problems. • Needs higher capacity and more reliability for NSLS-II devices (CPMUs and SCUs)

11. Schedule New Materials Cold Measurement IVEPU International Collaborations Gas Refrigerator SCUs Undulator Lab 2007 2008 2009 2010 2011 2012 1st user beam

12. 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