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Dynamical behavior is typical of X-ray production based on Compton backscattering process (CBP) that denotes the evolution and growth of the intracavity free-electron laser (FEL) radiation. The rate of scattered photons shoots up until the FEL reaches its saturation and the FEL-stimulated energy spread results in continuous degradation of the brightness of the X-rays. X-ray CBP intracavity FEL sources potentiate intracavity radiation which limits the brightness of the X-ray source. High power conventional lasers overcome these constraints. These devices offer larger CBP brightness.

The goal of the staged electron laser acceleration (STELLA) experiment is to demonstrate staging of the laser acceleration process whereby an inverse free electron laser (IFEL) will be used to prebunch the electrons, which are then accelerated in an inverse Cerenkov accelerator (ICA). As preparation for this experiment, a new permanent magnet wiggler for the IFEL was constructed and the ICA system was modified. Both systems have been tested on a new beamline specifically built for STELLA. The improved electron beam (e-beam) with its very low emittance (0.8 mm-mrad normalized) enabled focusing the e-beam to an average radius (1[Sigma]) of 65 [micro]m within the ICA interaction region. This small e-beam focus greatly enhanced the ICA process and resulted in electron energy spectra that have demonstrated the best agreement to date in both overall shape and magnitude with the model predictions. The electron energy spectrum using the new wiggler in the IFEL was also measured. These results will be described as well as future improvements to the STELLA experiment. Index Terms--Carbon dioxide lasers, electron accelerators, electron linear accelerators, inverse Cerenkov accelerators, inverse free electron laser, laser accelerators, linear accelerators, particle beam measurements.

SIR--As chair of the American Physical Society's Committee on International Freedom of Scientists, I wish to express my alarm about the kafkaesque situation confronting the Russian biologist Oleg Mediannikov, reported [...]