Previous studies of gamma ray spectra for different elements have been made by others using NaI(T1) (thallium activated, sodium iodide) detectors. This study has been done using a Ge(Li) (lithium drifted germanium) detector. Ge(Li) detectors feature much better energy resolution than do NaI(Tl) detectors. Using a Ge(Li) detector enables one to detect gamma rays closely spaced in energy that ordinarily would be unidentifiable due to the much poorer energy resolution of the NaI(Tl) detectors.Gamma ray spectra from 31 elements irradiated with 14-MeV neutrons have been examined, analyzed, and catalogued. These spectra can be used in the future as an aid in identifying elements using neutron activation analysis.

MSc. (ARST) North-West University, Mafikeng Campus, 2003

Thesis (M.S.)--Rochester Institute of Technoloty, 1989. / Includes bibliographical references (leaf 61).

Thesis--University of Florida. / Manuscript copy. Vita. Includes bibliographical references (leaves 154-167).

Thesis (M.S.)--University of Michigan, 1968.

Deaerated acidic, neutral, and basic aqueous N₂0 solutions were irradiated with Co-60 γ -rays in order to: 1) determine the primary yields, and 2) resolve anomalies in relative rate constant ratios of the type k(e⁻aq +S)/k(e⁻aq +N₂0). The yields of the gaseous products N₂, 0₂, and H₂ were determined as a function of both pH and [N₂0]. About 10⁻² M N₂0 is commonly used to evaluate relative rate constant ratios, but this [N₂0] scavenges not only hydrated electrons (e⁻aq ) but also another species, X, (where G(X) = 0.65±0.1), resulting in erroneous rate constant ratios. Yields of primary species found were: Ge⁻aq = 2.4±0.1, G H₂O* ̴ 1.6, and G,H₂⁺, = 0.35±0.05. Kinetic competition studies of the reaction of N₂0 and H⁺ with e⁻aq were undertaken in the concentration ranges 3 x 10⁻⁵ to 2 x 10⁻⁴ M H⁺ and 10⁻⁴ to 10⁻³ M N₂O. The results cannot be explained by: 1) simple competition; 2) charge transfer, or 3) two species being scavenged. They may be explained by assuming a conversion of N₂O to another species in acid solution. This acid species, suggested to be H₂N₂O₂, is apparently five times less reactive toward e⁻aq than is N₂0 in neutral solution. Deaerated neutal N₂0 solutions were irradiated at extremely high intensity with very short pulses of 0.52 Mev electrons. The yields of the gaseous products N₂, O₂, and H₂ were studied in order to examine an expected decrease in solute products, and to determine primary yields at high dose rates. As predicted, significant scavenging occurs for high dose rates only at N₂0 concentrations an order of magnitude larger than those at low dose rates. Also the scavenging, which is complete at ~ 10⁻² M N₂O for low intensity irradiations, is not complete at 2.6 x 10⁻² M N₂0 for high intensity irradiations. These results indicate that the radiation yield of scavengable hydrated electrons is significantly larger at the high intensity used. The yield of hydrogen in pure water (G(H₂) = 1.15±0.2) can be explained on the basis of inter-spur reactions of e⁻aq, H, and OH. / Science, Faculty of / Chemistry, Department of / Graduate

Call number: LD2668 .T4 1957 C45 / Master of Science

This study was an evaluation of the applicability of the neutron generator in identifying the manufacturing sources of drugs by studying; trace elements present in drug samples. The motivation w1as the possible assistance to law enforcement agencies in tracing illicit drugs to their origins.Eight samples of dextroamphetamine sulfate were used in the evaluation process. The samples were activated with a neutron generator producing a 14MMeV neutron flux of the order of 1010 neutrons/sec/cm2. A pair of NaI detectors and a multichannel analyzer were used to study, the decay spectra of the samples.The analytical system was found in most cases to be quite capable of detesting elements which were present in a few parts per million. Little success was encountered in detecting elements present at levels commonly considered to be trace amounts. Phosphorus, silicon, sodium, iron, and strontium where found in amounts ranging from 65 to 250,000 parts per million.Ball State UniversityMuncie, IN 47306

AbstractThe purpose of this study was the evaluation of various neutron activation cross sections using 2.8 MeV neutrons. This area of study was chosen because only a small amount of research has been done using generator produced 2.8 MeV neutrons.Most of the cross section values listed in the literature were small, requiring the use of various methods to increase the number of reactions occurring.A relative measure of the neutron flux was made using indium standards. The efficiency of the detection system was experimentally measured by the use of standardized radioisotopes.The product isotopes, produced by (n,ﻻ) or (u,n’ﻻ) reactions, and their measured activation cross sections were: 116mIn - 104 + 5 mb; 137mBa - 459 + 45 mb; 139Ba - 5.48 + 0.47 mb; 128I, - 38.5 + 3.0 mb; 56Mn - 4.28 + 0.34 mb; and 87mSr - 219 ± 26 mb. Errors from 4.8% for 116mIn to 12% for 87mSr were determined.Ball State UniversityMuncie, IN 47306

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 112-118). Also available on the Internet.