Thermomechanical analysis of a user filter assembly for undulator/wiggler operations at the Advanced Photon Source

This paper reports a thermo-mechanical study of a beamline filter for undulator/wiggler operations.It is deployed in conjunction with the current commissioning window assembly on the APS insertion device (ID) front ends. The beamline filter at the APS will eventually be used in windowless operations also. Hence survival and reasonable life expectancy of the filters under intense ID heat flux are crucial to the beamline operations. To accommodate various user requirements, the filter is configured to be a multi- choice type and 'smart' to a low only those filter combinations that will be safe to operate with a given ring current and beamline insertion device gap. However, this paper addresses only the thermo-mechanical analysis of individual filter integrity and safety in all combinations possible. The current filter design is configured to have four filter frames in a cascade with each frame holding five filters. This allows a potential 625 total filter combinations. Thermal analysis for all of these combinations becomes a mammoth task considering the desired choices for filter materials, filter thicknesses, undulator gaps, and the beam currents. The paper addresses how this difficult task has been reduced to a reasonable effort and computational level. Results from thermo-mechanical analyses of the filter combinations are presented both in tabular and graphical format.