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Advanced medical accelerator design
This report describes the design of an advanced medical facility dedicated to charged particle radiotherapy and other biomedical applications of relativistic heavy ions. Project status is reviewed and some technical aspects discussed. Clinical standards of reliability are regarded as essential features of this facility. Particular emphasis is therefore placed on the control system and on the use of technology which will maximize operational efficiency. The accelerator will produce a variety of heavy ion beams from helium to argon with intensities sufficient to provide delivered dose rates of several hundred rad/minute over large, uniform fields. The technical components consist of a linac injector with multiple PIG ion sources, a synchrotron and a versatile beam delivery system. An overview is given of both design philosophy and selected accelerator subsystems. Finally, a plan of the facility is described
Thermal rates for baryon and anti-baryon production
We use a form of the fluctuation-dissipation theorem to derive formulas
giving the rate of production of spin-1/2 baryons in terms of the fluctuations
of either meson or quark fields. The most general formulas do not assume
thermal or chemical equilibrium. When evaluated in a thermal ensemble we find
equilibration times on the order of 10 fm/c near the critical temperature in
QCD.Comment: 22 pages, 4 tables and 2 figures, REVTe
Slow Molecules Produced by Photodissociation
A simple method to control molecular translation with a chemical reaction is
demonstrated. Slow NO molecules have been produced by partially canceling the
molecular beam velocity of NO with the recoil velocity of the NO
photofragment. The NO molecules were photodissociated using a UV laser
pulse polarized parallel to the molecular beam. The spatial profiles of NO
molecules showed two peaks corresponding to decelerated and accelerated
molecules, in agreement with theoretical prediction. A significant portion of
the decelerated NO molecules stayed around the initial dissociation positions
even several hundred nanoseconds after their production.Comment: 17 pages, 4 figure
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