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Spectral properties of a tapered gap hard x-ray undulator

Journal Article · · Review of Scientific Instruments; (United States)
DOI:https://doi.org/10.1063/1.1144133· OSTI ID:6722692
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  1. Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

A tapered undulator, in which the entrance and exit magnetic gaps are different, will show an increase in the energy width of the harmonics compared to the nontapered case. This increase can occur without substantial broadening in the collimation of the undulator radiation. We present the spectral properties measured for a tapered 3.3-cm period prototype undulator of the Advanced Photon Source at the Cornell High Energy Synchrotron Source. The width of the on-axis first harmonic at 6.9 keV increased from 0.32 to 0.66 keV for a gap tapering of 12%. Minimal angular broadening in the first harmonic x rays was detected and measurements of off-axis radiation were also performed. The results are found to be in good agreement with model calculations.

DOE Contract Number:
W-31109-ENG-38
OSTI ID:
6722692
Journal Information:
Review of Scientific Instruments; (United States), Journal Name: Review of Scientific Instruments; (United States) Vol. 64:4; ISSN 0034-6748; ISSN RSINAK
Country of Publication:
United States
Language:
English