Simulation of insertion device performance: WAVE


WAVE [1] has been developed at BESSY over the years to calculate synchrotron radiation for almost arbitrary magnetic fields with high precision. The program also offers a variety of subroutines to calculate and manipulate magnetic fields as well as generating functions for symplectic tracking calculations.  The main features and options are given in the following list:

Magnetic fields

  • Simulation of helical and planar wigglers and undulators as analytical models or permanent magnet structure as well as dipoles, quadrupoles, and sextupoles with fringe fields
  • Simulation of magnetic field errors of insertion devices
  • In- and output of  magnetic fields via field maps or tables
  • Maxwell-conform parametrization and interpolation of magnetic fields

Synchrotron radiation

  • Calculation of amplitude, polarization (Stokes-vectors) and phase of the irradiated field (acceleration and velocity terms) of an electron traveling through an arbitrary magnetic field. The calculations can be performed numerically (e.g. for undulators or for edge radiation) or by application of Schwinger's formula.
  • Spatial and spectral distributions of synchrotron radiation and irradiated power and integration of the spatial distributions over an rectangular or circular aperture.
  • Taking beam emittance, energy spread, and coherence effects for arbitrary phase-space distrbutions into account
  • Propagation of the radiation field (Huygens' principle) e.g. to calculate the size of the source
  • Brightness calculations
  • Application of filters
  • Taking into account the spectral efficiency of detectors
  • Calculation of absorbed dose rate

Accelerator physics

  • Trajectories of electrons for arbitrary magnetic fields
  • Generating functions for symplectic tracking routines and linear transfer matrices
  • Effects of insertion devices on beam emittance, energy spread, and on time and degree of  beam polarization
  • Integrated quadrupole and sextupole  terms of magnetic fields
  • Representation of insertion device as a sequence of dipoles with edge focusing

Interfaces

  • User routines for data I/O, external magnetic field and treatment of tracking steps
  • Output of data files of the calculated radiation for the ray-tracing codes RAY [2] and PHASE [3]
  • Output of data files of generating functions and representation of insertion devices as a sequence of dipoles for tracking codes

WAVE has been used for the design of all insertion devices and the investigation of the insertion device – electron beam interaction, in particular of the superconducting wave-length shifters and  wigglers at the storage ring BESSY II.

 

[1] M. Scheer, Beschleunigerphysik und radiometrische Eigenschaften supraleitender Wellen-längenschieber, Humboldt-Universität zu Berlin, Dissertation 2008.
[2]  F. Schäfers, RAY - THE BESSY RAYTRACE PROGRAM F. Schäfers, In: Springer Series in Modern Optical Sciences: Modern Developments in X-Ray and Neutron Optics, eds. A. Erko, M. Idir, Th. Krist, A.G. Michette, Springer Berlin/Heidelberg, Vol. 137, 9-41 (2008) PDF
[3] J. Bahrdt, Wave Front Propagation: Design Code for Synchrotron Radiation Beamlines, Applied Optics 36 (1997), Vol. 19, p. 4367-4381