97 research outputs found

    Solar cell calibration facility validation of balloon flight data: A comparison of shuttle and balloon flight results

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    The Solar Cell Calibration Facility (SCCF) experiment was designed and built to evaluate the effect of the Earth's upper atmosphere on the calibration of solar cell standards. During execution of the experiment, a collection of carefully selected solar cells was flown on the shuttle, and reflown on a high-altitude balloon, then their outputs were compared. After correction to standard temperature and intensity values of 28 C and an Earth-Sun distance of 1 AU, the solar cell outputs during the two flights were found to be identical. The conclusion is therefore that the high-altitude balloon flights are very good vehicles for calibrating solar cells for use as space flight reference standards

    FURTHER STUDIES ON UNCERTAINTY, CONFOUNDING, AND VALIDATION OF THE DOSES IN THE TECHA RIVER DOSIMETRY SYSTEM: Concluding Progress Report on the Second Phase of Project 1.1

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    This is the concluding Progress Report for Project 1.1 of the U.S./Russia Joint Coordinating Committee on Radiation Effects Research (JCCRER). An overwhelming majority of our work this period has been to complete our primary obligation of providing a new version of the Techa River Dosimetry System (TRDS), which we call TRDS-2009D; the D denotes deterministic. This system provides estimates of individual doses to members of the Extended Techa River Cohort (ETRC) and post-natal doses to members of the Techa River Offspring Cohort (TROC). The latter doses were calculated with use of the TRDS-2009D. The doses for the members of the ETRC have been made available to the American and Russian epidemiologists in September for their studies in deriving radiogenic risk factors. Doses for members of the TROC are being provided to European and Russian epidemiologists, as partial input for studies of risk in this population. Two of our original goals for the completion of this nine-year phase of Project 1.1 were not completed. These are completion of TRDS-2009MC, which was to be a Monte Carlo version of TRDS-2009 that could be used for more explicit analysis of the impact of uncertainty in doses on uncertainty in radiogenic risk factors. The second incomplete goal was to be the provision of household specific external doses (rather than village average). This task was far along, but had to be delayed due to the lead investigator’s work on consideration of a revised source term

    ASSESSMENT OF VARIOUS TYPES OF UNCERTAINTY IN THE TECHA RIVER DOSIMETRY SYSTEM

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    Recent developments in evaluation of dose-response models in light of uncertain dose data (Stram and Kopecky 2003; Schafer and Gilbert 2006) have highlighted the importance of different types of uncertainties in the development of individual dose estimates. These include uncertain parameters that may be either shared or unshared within the dosimetric cohort, and also the nature of the type of uncertainty as either classical or Berkson. This report is an initial attempt to identify the nature of the various input parameters and calculational methods incorporated in the Techa River Dosimetry System (based on the TRDS-2000 implementation as a starting point, with additions for recently-developed capabilities). This report reviews the database, equations, and input parameters, and then identifies the author's interpretations of their general nature. It closes with some questions for the users of the data (epidemiologists and biostatisticians), so that the next implantation of the TRDS will provide the most useful information

    Individual Dose Calculations with Use of the Revised Techa River Dosimetry System TRDS-2009D

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    An updated deterministic version of the Techa River Dosimetry System (TRDS-2009D) has been developed to estimate individual doses from external exposure and intake of radionuclides for residents living on the Techa River contaminated as a result of radioactive releases from the Mayak plutonium facility in 1949–1956. The TRDS-2009D is designed as a flexible system that uses, depending on the input data for an individual, various elements of system databases to provide the dosimetric variables requested by the user. Several phases are included in the computation schedule. The first phase includes calculations with use of a common protocol for all cohort members based on village-average-intake functions and external dose rates; individual data on age, gender and history of residence are included in the first phase. This phase results in dose estimates similar to those obtained with system TRDS-2000 used previously to derive risks of health effects in the Techa River Cohort. The second phase includes refinement of individual internal doses for those persons who have had body-burden measurements or exposure parameters specific to the household where he/she lived on the Techa River. The third phase includes summation of individual doses from environmental exposure and from radiological examinations. The results of TRDS-2009D dose calculations have demonstrated for the ETRC members on average a moderate increase in RBM dose estimates (34%) and a minor increase (5%) in estimates of stomach dose. The calculations for the members of the ETROC indicated similar small changes for stomach, but significant increase in RBM doses (400%). Individual-dose assessments performed with use of TRDS-2009D have been provided to epidemiologists for exploratory risk analysis in the ETRC and ETROC. These data provide an opportunity to evaluate the possible impact on radiogenic risk of such factors as confounding exposure (environmental and medical), changes in the Techa River source-term data and the change of the approach to individual internal dose estimation (90Sr-body burden measurements and family correlations vs. village averages). Our further plan is to upgrade the TRDS-2009D and to complete a stochastic version of the dosimetry system
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