Varian Associates

About: Varian Associates is a based out in . It is known for research contribution in the topics: Beam (structure) & Wafer. The organization has 2160 authors who have published 2591 publications receiving 46002 citations.

Optical Detection of Magnetic Resonance in Alkali Metal Vapor

Abstract: This paper discusses two types of rf magnetic resonance experiments involving optical pumping in alkali vapor which have recently been suggested by Dehmelt. These experiments are, respectively, observation of a change of intensity at resonance of the transmitted pumping light, and observation of high-frequency intensity modulation in a second light beam (the "cross beam") incident at an angle to the first. The method of pumping used here is reviewed, together with some of the special assumptions on which it is based. The function of the light in monitoring population differences is treated as a separate matter from the pumping function; it is shown that the observed changes in transmitted light intensity can be correlated in a simple way with other observables of a spin system, and this leads to a simple explanation of the high-frequency modulation effects. A system of spin-\textonehalf{} particles subject to optical pumping and monitoring is then treated phenomenologically. The resulting equations have the same form as Bloch's equations except that (1) the time constants must include effects of the incident light, and (2) there is an additional term due to the cross beam which, however, is shown to have no effect on the shape of the resonance.The apparatus is described, together with experimental conditions under which signals have been observed. Possible applications of the technique include magnetic-field measurements, and studies of atomic constants of alkali metal isotopes.

X-ray and electron radiotherapy clinical treatment machine

Abstract: A radiotherapy machine includes a microwave powered accelerator to produce an energetic beam of charged particles, bending and focussing magnets to parallel scan the beam in a plane and collimators to make the resulting parallel scanned beam into paraxial rays of charged particles or X-rays. The beam is intensity modulated as it is scanned to control dosage spatial distribution. The subject is moved perpendicular to the scanning plane in order to treat a 3-dimensional shape.

Bandgap and lattice constant of GaInAsP as a function of alloy composition

Abstract: Published data for the composition dependence of the room-temperature bandgap (Eg) and lattice constant (ao) in the pseudobinary GayIn1-yAs, GayIn1-yP, GaAsxPl-x, and InAsxPl-x systems have been used to derive the following equations for the quaternary GayInl-yAsx Pl-x, alloys: $$\begin{gathered} a_o ({\AA}) = 5.87 + 0.18x - 0.42y + 0.02xy \hfill \\ E_g (eV) = 1.35 - x + 1.4y - 0.33xy - (0.758 - 0.28x)y(1 - y) \hfill \\ - (0.101 + 0.109y) x(1 - x). \hfill \\ \end{gathered} $$