Accurate measures of energies of gamma transitions in coincidence: 232U and 233U series of spectroscopy.

Author(s)

Zwinglio de Oliveira Guimarães Filho

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Física (IF/SBI)
• Defense date: 1998-12-03

Examining board members

Otaviano Augusto Marcondes Helene; Marina Fallone Koskinas; Nilberto Heder Medina

• Advisor: Otaviano Augusto Marcondes Helene

Abstract

This work presents an experimental method for determining gamma-ray energies employing HPGe detectors in coincidence experiments with precision similar to that obtained in single measurements. The method was applied in the measurement of gamma-ray energies from the decay chain of 233U and 232U. Covariance matrices between experimental data are as significant as variances in the evaluation of experimental uncertainties and indispensable for updating and combining experimental results. In this work the complete covariance matrices for the gamma-ray energies and for all parameters used in the developed procedure were determined in every stage of the work. The experimental apparatus used the Camac multidetector adapter developed in the Laboratório do Acelerador Linear. The data were analyzed using the software Bidim, developed during this work. The fitting procedure, based on the least squares method, was applied directly to the two-dimensional spectra. The best final precision of the gamma-ray energies was about 5eV. Chi-squared tests of the fit, always better than 15%, do not indicate the presence of inconsistencies. (AU)