Characterization of ALS undulator radiation---High {ital K}, taper, and the near field effect
- Advanced Light Source, Accelerator and Fusion Research Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)
The results of the measurements of spectral and angular distribution of the U5.0 (5 cm period) and U8.0 (8 cm period) Advanced Light Source (ALS) undulators are described. The spectra of on-axis undulator radiation were measured for various values of the deflection parameter {ital K}. In particular, the high {ital K} case was studied, representing the region between the undulator and wiggler limits. Good agreement in harmonic peak flux and width is found between the measurements and the computations that include the real magnetic field, the electron beam energy spread, and the electron beam emittance. The effect of the undulator taper on the spectral characteristics of the radiation was analyzed. At small taper ({similar_to}0.5% gap variation) significant reduction in peak brightness and flux of the fifth harmonic was observed with small effect on the fundamental. The near field effect in the undulator radiation was studied by measuring the off-axis spectral and angular distributions of the radiation. The broadening and the fine structure in the distributions at large off-axis angles were observed, resulting from the near field effect. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.
- Research Organization:
- Lawrence Berkeley National Laboratory
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 124843
- Journal Information:
- Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 11 Vol. 66; ISSN 0034-6748; ISSN RSINAK
- Country of Publication:
- United States
- Language:
- English
Similar Records
Spontaneous radiation from relativistic electrons in a tapered undulator
Spontaneous radiation from relativistic electrons in a taper undulator. Technical report