A Compact 4.4 Tesla Cryogenic Wavelength Shifter for the Taiwan Photon Source

Abstract

The feasibility of a compact 4.4 T in-vacuum cryogenic Pr2Fe14B-based wavelength shifter was studied at the Taiwan Photon Source. The overall dimensions of the magnet array are height 205 mm, length 240 mm, and width 160 mm; the magnet array operates at magnet gap 5 mm. The roll-off of the central field on the transverse axis was designed to be less than 0.1% between +/- 20 mm. The magnitudes of the integral multipole field error and the transverse tune shift as a function of transverse position were optimized to be less than 200 G cm and 4 x 10(-3) between +/- 15 mm. A reverse field occurred so that the Pr-Fe-B bulk became partially demagnetized near 295 K, but it was improved upon chamfering the iron poles near the regions of that reverse field to avoid demagnetization of the Pr-Fe-B bulk.