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An ultra high-speed, one-dimensional multi-channel detector for electrons and soft x-ray photons has been developed to permit full utilization of fluxes from third- and fourth-generation synchrotron radiation sources. The detector has 768 channels of buffered counters with a maximum linear countrate per channel exceeding 2 MHz. With an overall countrate of ∼2 GHz, this detector is approximately 100 times faster than any other presently available. The 48 μm spacing from channel to channel also provides excellent spatial resolution, and thus also excellent energy resolution with dispersive spectrometers. This detector represents several improvements in reliability and ruggedness over an earlier prototype. The detector is capable of operating in a typical UHV environment and is presently installed in a Scienta electron analyzer at the ALS for testing and first data taking. A total countrate exceeding 1 GHz and a position resolution of about two channels have been experimentally demonstrated. It should be possible to read out all 768 channels in as little as 150 μs for time-resolved and pump-probe experiments. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

A new recursive method for the simulation of photoelectron diffraction in solids within the cluster approach is presented. No approximations are made beyond the muffin-tin model, and in particular, an exact representation of the free-electron Green function is used. The new method relies upon a convenient separation of the free-electron Green function involving rotation matrices to reduce the computation time and storage demand. The multiple scattering expansion is iteratively evaluated using a divergence-free recursion method. The resulting computational demand scales as N[sup 2](l[sub max]+1)[sup 3] with the number of atoms in the cluster N and the maximum of the relevant angular momentum quantum numbers l[sub max]. Actual examples are given where N>1000 is needed for convergence within 5% in the calculated photoelectron intensity. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]