Efficient Coherent Mode Decomposition for Physical Optics Simulations of Beamlines and Experiments

Abstract We present simulations of the partially coherent undulator radiation (UR) propagation through several hard X-ray beamlines at NSLS-II, performed with SRW code, adopting two different memory- and CPU-efficient strategies / algorithms for mode decomposition (CMD). One these employs subtraction quadratic phase terms from 4D cross spectral density (CSD) a non-zero radius wavefront curvature, whereas other one applies CMD near beam waist, where is typically “flat”. show that, when performing on CSD wavefront, required numbers grid points meshes are largely reduced in both cases, compared to standard approaches. This dramatically reduces memory requirements (from TBs GBs) improves time-to-solution decomposed modes many hours parallel execution minutes sequential execution). Thanks implemented algorithms, tens or hundreds thousands wavefronts generated by independent electrons an undulator-based beamline low- intermediate- emittance synchrotron light source simulation over fewer than thousand major obtained CMD, which fully recovers structure UR before after beamline. The efficiency accuracy methods further demonstrated NSLS-II beamlines: HXN CHX.