Construction details of a 5" diameter 1.7 litre gas scintillation counter are given. The behaviour of the counter when containing He⁴ gas and a mixture of He⁴ and 10% Xe at various total pressures has been investigated. Two 5" photomultiplier tubes and a variety of different gas purifiers were tested in an attempt to obtain the best possible resolution. The pulse height was found to depend sensitively on the purification procedure adopted. A resolution of 10% for the Po²¹⁰ α-peak has been attained in two different chambers containing He⁴ plus 10% Xe. The voltage pulses rose in ≤300 nsec. Intense irradiation of a counter with 6 Mev x-rays caused only a slight increase in the maximum noise level already present from the photomultiplier tube. The behaviour of the counter as a fast neutron detector has been investigated using an uncollimated beam of 4.1 Mev neutrons. Pulses from recoiling protons and C¹² nuclei were observed as well as the He⁴ recoils. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

A study has been made which demonstrates the feasibility of developing a nuclear particle detector utilizing tunneling between superconductors. For optimum detector performance, temperatures lower than 1.2°K are mandatory. Accordingly, a He⁴ cryostat capable of being modified to a He³ cryostat has been constructed and tested. The detectors, which have been fabricated and tested at 1.4° K, consist of thin aluminum and lead films separated by an insulating layer of aluminum oxide. The d-c tunneling currents have been observed and are found to compare favourably with the results of previous workers. The d-c response of the device to gamma radiation was, as expected, unobservable. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 196-200).

The papers submitted in this volume present contributions and reviews on the physics of the scintillation process together with contributions to the development of scintillation detection techniques and the use of these techniques in nuclear physics research and in the applications of nuclear methods to other fields.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

published_or_final_version / Physics / Master / Master of Science

published_or_final_version / Physics / Master / Master of Science

No description available.

LD2668 .T4 1949 S73 / Master of Science

Scanning surveys of building surfaces and land areas are performed with radiation detection equipment to identify areas of elevated radioactivity. To quantify the extent and magnitude of the contamination, follow-up radiation surveys and soil sampling are usually required. The ability to accurately quantify discrete locations or "hot particles" of contamination requires a full understanding of the scanning detection efficiency of the instrument being used. A cylindrical sodium iodide detector's scanning detection efficiency was examined theoretically using the Monte Carlo N-Particle Code, version 4b, and examined experimentally using the Marianno Research Sled located in the Department of Nuclear Engineering, Oregon State University. A method is described for predicting instrument scanning detection efficiency for a 1 s observation interval over a range of scanning speeds using a series of static detection efficiency measurements. Testing of the prediction method and accuracy of predicted values was performed by comparison to experimentally determined values of scanning detection efficiency. Additionally, the validity of the predicted scanning detection efficiency values was tested by quantifying a radioactive source at a number of scanning speeds to quantitatively determine its activity. Activity values determined by scanning the source were compared against an activity value determined a by high purity germanium detection system. Results indicate that the method is both easy to perform and provides statistically accurate scanning detection efficiency values that can be utilized for the quantification of discrete locations or "hot particles" of radioactive contamination. / Graduation date: 2002