T. B. Novey

Correction for Phosphor Backscattering in Electron Scintillation Spectrometry

An iterative numerical integration procedure has been developed to correct both beta spectra and differential beta‐gamma directional correlations for the effects of finite instrument energy resolution including the effect of backscattering from a scintillation detector.The method has been tested and found to reproduce the true spectral shape in the cases of Re186, Au198, Tl204, and to allow separation of composite beta spectra as in the case of W187. Application of the method is limited to maximum beta energies exceeding 200 kev.

RaDEF Standard Sources for Beta‐Disintegration Rate Determinations

The preparation and use of calibrated RaDEF equilibrium sources for absolute beta‐counting is described. The sources are essentially weightless and are mounted on a thin backing to reduce self‐absorption and back‐scattering correction problems. Calibration was done by determination of the alpha‐disintegration rate of RaF in a parallel plate alpha‐ionization chamber. No secondary standards are required and the sources can be recalibrated at any time.As an example of the application of such standards, details of the calibration of a P32 solution distributed by the Bureau of Standards for intercalibration in February 1949 are given. The final result is 88.8 mrd/ml at 8 A.M. C.D.T. March 1, 1949. The precision of the measurement is 0.3 percent. The accuracy is estimated to be 1–2 percent.

Design and Construction of a System of Pulsed Magnets

A system of two pulsed iron‐free magnets, designed for an experiment in high energy physics is described. One of these is a small solenoid, with a working volume of about 35 cm3, pulsed at 200 kgauss; the other is a large magnet with a volume of about 6 liters, pulsed at a nominal 15 kgauss. Construction details, working lifetimes, and details of switch gear are discussed.

The Interdependence of Solid State Physics and Angular Distribution of Nuclear Radiations

Publisher Summary This chapter presents a combination of the view of solid state and nuclear physics and indicates the information concerning the structure of the solid state that may be obtained from experiment. The terms “angular distribution” and “angular correlation” are used for a wide class of phenomena in which the probability for emission of a nuclear radiation is described as a function of the angle between the emitted radiation and some fixed direction. The chapter presents the pertinent theory and the experimental evidence concerning the interrelation of the angular correlation of nuclear radiations and the structure of condensed matter. Generally speaking, the methods of angular correlation allow the determination of the magnetic fields and electric field gradients at the position of the radioactive nucleus whose radiation is studied. Most of the information obtained is related closely to that obtained from studies of nuclear magnetic and electron paramagnetic resonance. Although the resonance methods are more precise in general, the techniques of angular correlation offer two advantages.