CHARACTERIZATION OF FLUORESCENT NUCLEAR TRACK DETECTORS AS CRITICALITY DOSIMETERS II.

Fluorescent nuclear track detectors (FNTDs) as criticality dosimeters for both neutrons and gamma are further characterized in terms of angular dependence and quick dose assessment. The power spectrum integral depth profiles obtained from stacks of fluorescent images acquired within FNTDs exposed to a broad spectrum neutron field at various angles are analyzed to determine a calibration curve for angular dependence. MCNPX simulations were shown to be in good agreement with experimental results. A prototype triage reader was also designed and tested for quick assessment of dose. An unfolding technique incorporating both energy dependence and angular dependence is discussed. The advantages and shortcomings of using FNTDs in the event of a criticality excursion accident are analyzed.

ENERGY RESPONSE OF FLUORESCENT NUCLEAR TRACK DETECTORS OF VARIOUS COLORATIONS TO MONOENERGETIC NEUTRONS.

The neutron-energy dependence of the track-counting sensitivity of fluorescent nuclear track detectors (FNTDs) at two ranges of Mg doping, resulting in different crystal colorations, was investigated. The performance of FNTDs was studied with the following converters: Li-glass for thermal to intermediate-energy neutrons, polyethylene for fast neutrons, and polytetrafluoroethylene (Teflon™) for photon- and radon-background subtraction. The irradiations with monoenergetic neutrons were performed at the National Physics Laboratory (NPL), UK. The energy range was varied from 144 keV to 16.5 MeV in the personal dose equivalent range from 1 to 3 mSv. Monte Carlo simulations were performed to model the response of FNTDs to monoenergetic neutrons. A good agreement with the experimental data was observed suggesting the development of a basic model for future MC studies. Further work will focus on increasing FNTD sensitivity to low-energy neutrons and developing a faster imaging technique for scanning larger areas to improve counting statistics.

The incidence of stressful life events of elementary school-aged children.

Certain events, commonly found in the life histories of children, have been characterized as potentially stressful (Rutter, 1981). There is some evidence to support the hypothesis that these events play a role in the etiology of various disorders, although the nature of that relationship is not clear (Dohrenwend & Dohrenwend, 1974). Yet that relationship remains the subject of considerable interest, as can be seen by the number of studies on the influence of stressful life events on children's emotional adjustment and school performance (Boike, Gesten, Cowen, Felner, & Francis, 1978; Felner, Ginter, Boike, & Cowen, 1981; Felner, Stolberg, & Cowen, 1975; Gesten, Scher, & Cowen, 1981; Felner, Stolberg, & Cowen, 1975; Gesten, Scher, & Cowen, 1978; Rolf & Garmezy, 1974; Sandler & Block, 1979; Siegel, 1981). Sandler and Ramsey (1980) have suggested that the role of life events as stressors can be understood to be a function of, among other things, the frequency of occurrence of events. For research and clinical assessment purposes, baseline data on the incidence of stressful life events of children seem to be necessary. In order to collect and organize baseline data, the relevant demographic variables must be identified. It was hypothesized that there might be two relevant demographic variables: age and socioeconomic status (SES). The purposes of this study were to (a) conduct a survey to gather baseline data on the incidence of stressful life events of children, and (b) examine the effects of age and SES on the number of events reported.