Publication Date


Advisor(s) - Committee Chair

D.F. Humphrey, N.F. Six, C.A. Logsdon

Degree Program

Department of Physics and Astronomy

Degree Type

Master of Science


The increasing trend towards the use of activation analysis as an analytic means of identifying elements and determining their relative abundance demands more accurate values of reaction cross-sections. Accurate values of cross-sections are also important in the investigation of possible shell effects in reaction mechanisms. Many activation cross-sections for reactions produced by 14 MeV neutrons have been measured because of the relative ease with which this energy of neutrons can be produced. Low voltage accelerators are capable of producing 14. MeV neutrons by the 3H( d,n)4He reaction. Although many people(1-5) have measured the (n,2n) reaction cross-sections for a multitude of stable isotopes, their values differ considerably for a particular range or they report large uncertainties in their measured values. By using improved counting and flux monitoring techniques, an attempt will be made to more accurately determine the values of the (n,2n ) reaction cross-sections for 71Ga, 106Cd, and 138Ba.

The values for the (n,2n) reaction cross-sections for these three isotopes are determined by the simultaneous activation of the isotope in question and two copper disks. Each sample is sandwiched between the two foils during activation. Since the 63Cu(n,2n) 62Cu reaction cross-section for 14 MeV neutrons has been accurately measured, the activity produced in the copper disks is used in the determination of the (n,2n) reaction cross-sections. The purpose of this thesis is to more accurately determine *he values of the (n,2n) reaction cross-sections for 71Ga, 106Cd, and 138Ba by improved techniques.


Engineering Physics | Physical Sciences and Mathematics | Physics