Date of Award
Master of Science
Department of Engineering Physics
Robert Hengehold, PhD.
The Department of Defense is interested in lithium tetraborate (Li2B4O7) crystals for their possible use as a solid state neutron detection material. With large concentrations of 6Li and 10B, it has a high neutron capture cross section. Furthermore, the crystal fluoresces in the presence of ionizing radiation, making it an attractive candidate for a scintillating detection device. However, there is a lack of fundamental knowledge about the material characteristics, particularly with regard to its fluorescent spectrum. Cathodoluminescence measurements were conducted on undoped and doped samples of lithium tetraborate in order to characterize the nature of its fluorescent spectra under different environmental conditions. Measurements were made using a vacuum ultraviolet cathodoluminescence system specifically designed to detect high energy photons emitted in wide band gap materials. The cathodoluminescent spectra from 10 K to room temperature was characterized for six different lithium tetraborate crystals: three undoped crystals and one each doped with silver, copper, and manganese. Thermoluminescence measurements were conducted using a Harshaw Model 3500 Manual TLD Reader. After electron irradiation from the cathodoluminescence experiment, the samples were heated from 50 °C to 250 °C at a heating rate of 1 °C per second. The thermoluminescence measurements provided insight into the carrier trapping ability of the crystals after electron irradiation.
DTIC Accession Number
Hadfield, Zachary L., "Cathodoluminescence and Thermoluminescence of Undoped LTB and LTB:A (A = Cu, Ag, Mn)" (2013). Theses and Dissertations. 929.