A NEW POWER SUPPLY SYSTEM FOR THE IEX PROJECT

A new IEX beamline providing circularly polarized xrays that will cover photon energies from 250 eV to 2.5 keV is under development at the APS. Because of the unique requirements of the electromagnetic variably polarizing undulator (EMVPU) constructed for this beamline, a new power supply system design is required. The undulator will contain sixteen sets of electromagnetic coils--two main, two quasi-periodic, and twelve correctors. The undulator will incorporate variable polarization control and reduction of the magnetic fields at so-called quasi-periodic pole locations for the purpose of suppressing the higher-order radiation harmonics. The challenges met in the power supply system design for the project will be discussed.