Several ideas have been proposed to ‘condition’ an electron beam prior to the undulator of a Free-Electron Laser (FEL) by increasing each particle’s energy in proportion to the square of its transverse betatron amplitude. This conditioning enhances FEL gain by reducing the axial velocity spread within the electron bunch. We demonstrate that for symplectic beamlines, and independent of the metho...

Numerical integration of the free-electron laser equations usually starts with a small arbitrary value of input field, to allow the FEL instability to show itself. This procedure fails to reproduce the start-up of the real laser and the time or distance to saturation will depend on the arbitrary initial value. The procedure is obviously valid only for initial field-values larger than the random...

The modulation and engineering of the free-electron wave function bring new ingredients to electron-matter interaction. We consider dynamics a passing by two-level system fully quantum mechanically study enhancement interaction from function. In presence resonant function, we show that electron energy loss gain spectrum is greatly enhanced for coherent initial state system. Thus, modulated can ...

in this paper, 4,4ʹ-bipyridinium dichloride  supported sba-15 (sba@bipy2+ 2cl-) was used for the synthesis of dihydropyrimidinones. the synthesized catalyst was characterized by ft-ir spectroscopy, scanning electron microscopy (sem), transmission electron microscopy (tem) and thermogravimetric analysis (tga). this nanocomposite was shown to be an efficient heterogeneous catalyst for the synthes...