Year: 2025
Type: article
Abstract: We propose a vertically polarized superconducting multipole wiggler (V-SC-MPW) that enables the use of vertically polarized hard X-rays with minimal impact on beam quality. Vertical polarization facilitates unique experimental setups by allowing horizontal arrangement of optical equipment, which is difficult to realize with horizontally polarized X-rays. However, significant emittance growth has prevented the adoption of such vertically polarized, high-field devices in third-generation light sources. To address this challenge, the V-SC-MPW employs a short-period design. By utilizing Nb 3 Sn superconducting wires, which have a critical current density approximately 10 times higher than that of conventional NbTi, the period length can be shortened while maintaining the required magnetic field, thereby reducing the beam orbit amplitude and the resulting emittance growth. A case study that considers the introduction of the V-SC-MPW into PF-HLS, a future light source planned at KEK, shows that, with a horizontal magnetic gap of 30 mm, a design featuring a peak magnetic field of 2.44 T, a period length of 85 mm and an orbit amplitude of 54 µm at a beam energy of 2.5 GeV is feasible. This seven-period V-SC-MPW, assumed to be installed in a non-achromatic straight section of PF-HLS, is estimated to result in emittance growths of 15.6 pm rad horizontally and 1.0 pm rad vertically. These minimal impacts indicate that the short-period V-SC-MPW is a promising insertion device for utilizing vertically polarized hard X-rays in modern low-emittance rings with intermediate beam energies.
Source: Journal of Synchrotron Radiation
Institution: High Energy Accelerator Research Organization
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,180
OpenAlex ID: W4411368840