Accession Number : AD0455709

Title :   EFFECTS OF SAMPLE SIZE AND STATISTICAL WEIGHTS ON FLUCTUATIONS IN THE C12(C12, ALPHA)NE20 REACTIONS,

Corporate Author : ATOMIC ENERGY OF CANADA LTD CHALK RIVER ONTARIO

Personal Author(s) : Almqvist, E. ; Kuehner, J. A. ; McPherson, D. ; Vogt, E. W.

Report Date : 04 MAY 1964

Pagination or Media Count : 15

Abstract : Absolute values of the differential cross sections for the reaction C12(C12, alpha)Ne20 to the ground and 1.63-MeV states are given at 100keV energy intervals between 20.3- and 25.6-MeV bombarding energy at eight equally spaced angles between 3 and 73 degrees in the laboratory, as well as some more detailed angular distributions at selected energies. Both differential cross sections and angle-integrated data are shown to fluctuate strongly with energy. A quantitative comparison between the properties of the fluctuations and the predictions of the statistical theory of the compound nucleus (used in the spirit of Ericson) is presented. The effects of making observations on a sample of finite size are illustrated in detail and are shown in some cases to lead to results that are readily mistaken for evidence of direct interaction. Fluctuations of cross sections involving sums of several incoherent components of different weights are calculated and compared with experiment and with the usual estimates based on equal weights. The proper weight coefficients for the calculation are derived from the treatment of the average cross sections in an accompanying paper. (Author)

Descriptors :   (*NUCLEAR REACTIONS, DIFFERENTIAL CROSS SECTIONS), (*DIFFERENTIAL CROSS SECTIONS, NUCLEAR REACTIONS), CARBON, ALPHA PARTICLE REACTIONS, NEON, ION BEAMS, STATISTICAL FUNCTIONS, GROUND STATE, NUCLEAR SPINS, MONTE CARLO METHOD, STATISTICAL ANALYSIS.

Distribution Statement : APPROVED FOR PUBLIC RELEASE