Simulations of Hole Coupling in Different Resonator Configurations

Simulations of hole coupling are presented for two different resonator configurations: nearly concentric and nearly confocal. The influence of varying electron beam current or energy is studied

The infrared spectrum of pyrazine in its metastable triplet state. A free-electron-laser study

Vibrational transitions of pyrazine in the lowest triplet state have been observed as transient changes in the intensity of the phosphorescence induced by the free-electron laser FELIX. All seven fundamental infrared-active modes in the range of 250 to 1600 cm(-1) have been detected and all vibrational frequencies are found to be considerably lower than the corresponding ones in the ground state. (C) 1997 American Institute of Physics

Enhancement of Fel Efficiency by Using Short Electron Pulses

In this paper we show that for an intermediate gain free electron laser oscillator, the efficiency is dramatically enhanced by operating with electron pulses shorter than the slippage distance. We discuss both the consequences of operating at longer wavelengths where lethargy effects are important and the implications of working with short electron pulses when inhomogeneous broadening is important. The discussion is supported by a one-dimensional multiparticle simulation that takes into account both saturation and short pulse effects

Measurements of the Length of Intense Electron Bunches Using a Capacitive Probe and a 20-Ghz Sampling Oscilloscope

Measurements of the longitudinal profile of intense electron bunches with an energy of 100 keV, using a button monitor and a 20-GHz sampling oscilloscope, are presented in this paper. At this energy, which is intermediate between nonrelativistic and relativistic, the button response is quite different from the response in either of the two extreme cases. An analytical model of the response is presented. The resolution derived from this model is 80 ps at 100-keV beam energy. For more relativistic beams, a resolution of about 40 ps appears to be feasible. Great care has to be taken in avoiding resonances