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The Dosimetry Group designs, fabricates, and calibrates bent-crystal optics and diagnostic spectrometers for customers around the world.
These have been fielded to help characterize the performance and x-ray spectra from advanced medical x-ray sources, laser-produced plasmas, terawatt pulsed accelerators, electron cyclotron resonance ion sources, electron-beam ion traps, intense ultrafast laser sources, and inverse-Compton backscatter sources. A recent model was developed and demonstrated at the Extended Performance laser of the University of Rochester's Laboratory for Laser Energetics (OMEGA-EP). The accompanying graphic demonstrates one diagnostic capability of these instruments. The Mo K spectral lines are shown to differ markedly from plasmas created with relatively short laser pulses (74 ps) compared to 1 ns irradiations. The broadening and shift to higher energy reveals the production mechanisms and the charge state(s) of highly charged ions under long-pulse irradiation; the narrow lines produced with picosecond pulses were found to be from neutral species (too fast for ion production).