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Twelve Years Of Neutron Personnel Dosimetry Intercomparison Studies At Oak Ridge National Laboratory
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Book Synopsis Twelve Years of Neutron Personnel Dosimetry Intercomparison Studies at Oak Ridge National Laboratory by :
Download or read book Twelve Years of Neutron Personnel Dosimetry Intercomparison Studies at Oak Ridge National Laboratory written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To provide an opportunity for dosimetrists to test and calibrate their personnel neutron monitoring systems in a variety of incident radiation fields, the staff of the Dosimetry Applications Research (DOSAR) Facility at the Oak Ridge National Laboratory (ORNL) has conducted personnel dosimetry intercomparison studies (PDIS) periodically since 1974 and annually since 1976 (Si82, Sw87). During these studies, personnel dosimeters are mailed to ORNL, mounted on phantoms and exposed to low-level (less than 15 mSv) dose equivalents in mixed-radiation fields mainly produced using the Health Physics Research Reactor (HPRR) at ORNL (Au65), and then returned to the participants for evaluation. Reported dose equivalents are compared to reference values provided by the DOSAR staff and to results reported by individual organizations which made measurements under identical conditions. These intercomparisons, which require no fee and are open to any organization interested in external personnel dosimetry, have provided more data concerning neutron dosimeter performance characteristics in mixed-radiation fields than any other periodic open test program conducted to date. The following text presents a summary and analysis of neutron dose equivalent measurements reported for the seventh through twelfth intercomparisons (1981-1986) using the HPRR as the source of radiation. Particular factors examined include low dose equivalent sensitivity and measurement accuracy for the basic types of neutron personnel dosimeters. 5 refs., 1 fig.
Book Synopsis Summary and Analysis of Neutron Measurements Conducted During the Oak Ridge Personnel Dosimetry Intercomparison Studies by :
Download or read book Summary and Analysis of Neutron Measurements Conducted During the Oak Ridge Personnel Dosimetry Intercomparison Studies written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 1974, neutron personnel dosimetry intercomparison studies (PDIS) have been conducted annually at the Oak Ridge National Laboratory's (ORNL) Dosimetry Applications Research Facility. During these studies, neutron dosimeters are mailed to ORNL, exposed to low-level (less than 15 mSv) dose equivalents in a variety of mixed-radiation fields produced using the Health Physics Research Reactor (HPRR), and then returned to the participants for evaluation. Beginning with the Seventh PDIS in 1981, interest and participation in the Oak Ridge intercomparisons increased significantly and consistent and documented techniques for determining reference neutron dose equivalents for the HPRR were introduced. This document presents a summary and analysis of approximately 3400 neutron dose equivalent measurements made using a variety of personnel dosimeters and reported for PDIS 7-12. 16 refs., 3 tabs.
Book Synopsis Personnel-dosimetry Intercomparison Studies at the Oak Ridge National Laboratory by :
Download or read book Personnel-dosimetry Intercomparison Studies at the Oak Ridge National Laboratory written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 1974, seven annual personnel dosimetry intercomparison studies have been conducted at the Oak Ridge National Laboratory using the Health Physics Reactor. These studies have produced more than 2000 measurements by 72 participating organizations of neutron and gamma dose equivalents between 0.1 to 15.0 mSv in six mixed radiation fields. The relative performance of three basic types of personnel neutron dosimeters (nuclear emulsion film, thermoluminescent, and track-etch) and two basic types of gamma dosimeters (film and thermoluminescent) was assessed based on experimental results obtained during the seven intercomparisons.
Book Synopsis Fourth Personnel Dosimetry Intercomparison Study by :
Download or read book Fourth Personnel Dosimetry Intercomparison Study written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The fourth Personnel Dosimetry Intercomparison Study was held at the Oak Ridge National Laboratory's Dosimetry Applications Research Facility during March 15-23, 1978. The Health Physics Research Reactor (HPRR) used unshielded, with a 12-cm-thick Lucite shield, a 20-cm-thick concrete shield, or a 5-cm-thick steel and 15-cm-thick concrete shield, and provided four neutron and gamma-ray spectra. Then the dose was calculated based on the HPRR neutron spectra and dose conversion factors which had been determined previously for the four spectra. The results of these personnel dosimetry intercomparison studies reveal that estimates of dose equivalent vary over a wide range. The standard deviation of the mean of participants data for gamma measurements was in the range of 29 to 43%; for neutrons it was 57 to 188%. (PCS).
Book Synopsis Neutron Personnel Dosimetry Intecomparison Studies by :
Download or read book Neutron Personnel Dosimetry Intecomparison Studies written by and published by . This book was released on 1991 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Dosimetry Applications Research (DOSAR) Group at the Oak Ridge National Laboratory (ORNL) has conducted sixteen Neutron Personnel Dosimetry Intercomparison Studies (PDIS) since 1974. During these studies dosimeters are mailed to DOSAR, exposed to low-level (typically in the 0.3 -- 5.0 mSv range) neutron dose equivalents in a variety of mixed neutron-gamma radiation fields, and then returned to the participants for evaluation. The Health Physics Research Reactor (HPRR) was used as the primary radiation source in PDIS 1--12 and radioisotopic neutron sources at DOSAR's Radiation Calibration Laboratory (RADCAL) were mainly used, along with sources and accelerators at cooperating institutions, in PDIS 13--16. Conclusions based on 13,560 measurements made by 146 different participating organizations (102 - US) are presented.
Book Synopsis Performance Characteristics of Neutron Personnel Dosemeters Used in the Oak Ridge Intercomparison Studies by :
Download or read book Performance Characteristics of Neutron Personnel Dosemeters Used in the Oak Ridge Intercomparison Studies written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To provide an opportunity for dosimetrists to test and calibrate their neutron personnel monitoring systems, the staff of the Dosimetry Applications Research Facility at the Oak Ridge National Laboratory (ORNL) has conducted personnel dosimetry intercomparison studies (PDIS) periodically since 1974. During these studies, neutron dosemeters are mailed to ORNL, exposed to low-level (less than 15 mSv) dose equivalents in a variety of mixed-radiation fields produced using the Health Physics Research Reactor (HPRR), and then returned to the participants for evaluation. Beginning with the Seventh PDIS in 1981, interest and participation in the Oak Ridge intercomparisons increased significantly and consistent and documented methods for determining reference neutron dose equivalents for the HPRR were introduced. This paper presents a summary and analysis of about 3450 neutron dose equivalent measurements reported for PDIS 7 through 12 (1981-1986) with particular emphasis on low dose equivalent sensitivity, accuracy and precision, and performance relative to accreditation standards for the basic types of personnel dosimetry systems. (16 refs., 3 tabs.
Book Synopsis Fifth Personnel Dosimetry Intercomparison Study by :
Download or read book Fifth Personnel Dosimetry Intercomparison Study written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The fifth Personnel Dosimetry Intercomparison Study (PDIS) was conducted at the Oak Ridge National Laboratory's (ORNL) Dosimetry Applications Research (DOSAR) facility on March 20-22, 1979. This study is the latest PDIS in the continuing series started at the DOSAR facility in 1974. The PDIS is a three day study, typically in March, where personnel dosimeters are mailed to the DOSAR facility, exposed to a range of low-level neutron radiation doses (1 to 15 mSv or equivalently, 100 to 1500 mrem) and neutron-to-gamma ratios (1:1-10:1) using the Health Physics Research Reactor (HPRR) as the radiation source, and returned to the participants for evaluation. This report is a summary and analysis of the results reported by the various participants. The participants are able to intercompare their results with those of others who made dose measurements under identical experimental conditions.
Book Synopsis Personnel Dosimetry Intercomparison Studies at the ORNL Health Physics Research Reactor by :
Download or read book Personnel Dosimetry Intercomparison Studies at the ORNL Health Physics Research Reactor written by and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Health Physics Research Reactor (HPRR), used unshielded, with a 12-cm-thick Lucite shield or a 13-cm-thick steel shield, provided three neutron and gamma-ray spectra for personnel dosimetry intercomparison studies. The characterisitcs of these fields, such as neutron energy spectrum, intensity, and uniformity, had been measured previously during nuclear accident dosimetry studies. Exposures were made to simulate total exposures likely to be encountered in personnel dosimetry. Neutron dose equivalents of the order of 500 mrem were produced. Dosimeters were mounted on the trunk section of water-filled phantoms, the front edges of which were located three meters from the reactor center. When shields were used they were placed at two meters. Sulfur pellets exposed at a standard location on the reactor during the intercomparison were used to calculate values of tissue kerma for neutrons at the three meter position based on previous measurements. Hurst proportional counter measurements made at the time of the exposures are in good agreement with these results. The gamma component of dose, typically of the order of a few tens of mrad, was measured with LiF thermoluminescent dosimeters (TLD's). Using the fission yield and the calculated leakage of the HPRR, the neutron fluence was calculated for each reactor run. Then the dose was calculated based on the HPRR neutron spectra and the dose conversion factors which had been calculated previously for the three spectra. The results of these personnel dosimetry intercomparison studies reveal that estimates of dose equivalent vary over a wide range. The standard deviation of the mean of participants data was typically in the range of +-30 to +-40%. It is anticipated that this type of dosimetry intercomparison study will be worthwhile on an annual basis until the problems in dosimeter response and interpretation have been identified and solved.
Book Synopsis Sixth Personnel Dosimetry Intercomparison Study by :
Download or read book Sixth Personnel Dosimetry Intercomparison Study written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Sixth Personnel Dosimetry Intercomparison Study was conducted March 25 to 27, 1980, at the Oak Ridge National Laboratory. Dosimeters from 28 participating agencies were mounted on anthropomorphic phantoms and exposed to a range of low-level dose equivalents (1.8 to 11.5 mSv neutron, 0.1 to 1.1 mSv gamma) which could be encountered during routine personnel monitoring in mixed radiation fields. The Health Physics Research Reactor (HPRR) operated in the steady-state mode served as the source of radiation for six separate exposures. Lucite and concrete shields along with the unshielded reactor were used to provide three different neutron and gamma spectra. Results reported by the participating agencies showed that TLD-albedo and TLD-700 dosimeters generally provided the most accurate measurements of neutron and gamma dose equivalents, respectively. Film was found to be unsatisfactory for measuring neutron doses produced by HPRR spectra in that measured dose equivalents were much lower than reference values. The TLD-100 dosimeters yielded gamma doses which were much too high indicating that this dosimeter type is generally unsuitable for use in mixed radiation fields similar to those encountered in this study without the use of large correction factors. Although the overall reported results exhibited improvement in performance relative to previous intercomparison studies, the composite measured data showed variations of more than a factor of 2 between measurements of the same exposure made by different agencies.
Book Synopsis Summary and Analsysis of the 1986 ORNL Personnel Dosimetry Intercomparison Study by :
Download or read book Summary and Analsysis of the 1986 ORNL Personnel Dosimetry Intercomparison Study written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Twelfth Personnel Dosimetry Intercomparison Study was conducted at the Oak Ridge National Laboratory (ORNL) during April 14 to 17, 1986. Objectives of this study were to determine neutron dosimeter performance characteristics at neutron dose equivalent levels near the minimum specified for accreditation testing programs and to provide several radiation fields different from those that have been considered in prior ORNL intercomparisons. Dosimeter badges from 49 participating organizations were mounted on Lucite block phantoms and exposed to six mixed-radiation fields (five using the Health Physics Research Reactor and one using a PuBe source) with neutron dose equivalents of about 1.5 mSv and gamma dose equivalents between 0.04 and 5.37 mSv. Results of this study indicated that participants had no difficulty obtaining measurable indication of neutron exposure at dose equivalent levels of about 1.5 mSv. Average neutron results for all dosimeter types were within approximately 60% of reference values with hard spectra being more accurately measured than soft spectra. Considering all irradiations, albedo and direct interaction TLD systems provided about the same performance characteristics. With regard to precision, about 58% of the reported neutron results had single standard deviations within 10% at the means which indicates that precision was not a problem relative to accuracy for over half of the participants. Average gamma results varied from 0.98 to 2.22 times reference values for all exposures with TLD systems being more accurate than film. Some participants, especially those using film, had difficulty obtaining measurable indication of gamma exposures at dose equivalent levels lower than 0.09 mSv. About 69% of all neutron results and 77% of all gamma results met regulatory standards for measurement accuracy and approximately 65% of all neutron data satisfied national dosimetry accreditation criteria for accuracy plus precision. 18 refs., 1 fig., 30 tabs.
Book Synopsis Performance of Neutron and Gamma Personnel Dosimetry in Mixed Radiation Fields by :
Download or read book Performance of Neutron and Gamma Personnel Dosimetry in Mixed Radiation Fields written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: From 1974 to 1980, six personnel dosimetry intercomparison studies (PDIS) were conducted at the Oak Ridge National Laboratory (ORNL) to evaluate the performance of personnel dosimeters in a variety of neutron and gamma fields produced by operating the Health Physics Research Reactor (HPRR) in the steady state mode with and without spectral modifying shields. A total of 58 different organizations participated in these studies which produced approximately 2000 measurements of neutron and gamma dose equivalents on anthropomorphic phantoms for five different reactor spectra. Based on these data, the relative performance of three basic types of neutron dosimeters (nuclear emulsion film, thermoluminescent (TLD), and track-etch) and two basic types of gamma dosimeters (film and TLD) in mixed radiation fields was assessed.
Book Synopsis Third Personnel Dosimetry Intercomparison Study by :
Download or read book Third Personnel Dosimetry Intercomparison Study written by and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The third Personnel Dosimetery Intercomparison Study was held at the Oak Ridge National Laboratory Dosimetry Applications Research Facility during March 15--16, 1977. The Health Physics Research Reactor (HPRR), used unshielded, with a 12-cm-thick Lucite shield or a 13-cm-thick steel shield, provided three neutron and gamma-ray spectra. The characteristics of these fields such as neutron energy spectra, intensity, and uniformity had been measured previously during nuclear accident dosimetry studies. Exposures were made to simulate total exposures likely to be encountered in personnel dosimetry. Neutron dose equivalents of the order of 500 millirem were produced by controlling the reactor power level and exposure time. Dosimeters were mounted on the trunk section of water-filled phantoms, the front edges of which were located 3 m from the reactor center. When shields were used they were placed at 2 m from the core. Sulfur pellets exposed at a standard location on the reactor during the intercomparison were used to calculate values of tissue kerma for neutrons at the 3-m position based on previous measurements. Using the fission yield and the calculated leakage of the HPRR, the neutron fluence was calculated for each reactor run. Then the dose was calculated based on the HPRR neutron spectra and the dose conversion factors, which had been calculated previously for the three spectra. The results of these personnel dosimetry intercomparison studies reveal that estimates of dose equivalent vary over a wide range. The standard deviation of the mean of participants data was in the range of 25 to 50%.
Book Synopsis Eleventh ORNL Personnel Dosimetry Intercomparison Study, May 22-23, 1985 by :
Download or read book Eleventh ORNL Personnel Dosimetry Intercomparison Study, May 22-23, 1985 written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Eleventh Personnel Dosimetry Intercomparison Study was conducted at the Oak Ridge National Laboratory (ORNL) during May 22-23, 1985. Dosimeter badges from 44 participating organizations were mounted on Lucite block phantoms and exposed to four mixed-radiation fields with neutron dose equivalents around 5 mSv and gamma dose equivalents between 0.1 and 0.7 mSv. Results of this study indicated that no participants had difficulty obtaining measurable indication of neutron exposure at the provided dose equivalent levels, and very few had difficulty obtaining indication of gamma exposure at dose equivalents as low as 0.10 mSv. Average neutron results for all dosimeter types were within 20% of reference values with no obvious spectrum dependence. Different dosimeter types (albedo, direct interaction TLD, film, recoil track, and combination albedo-track) with 10 or more reported measurements provided average results within 35% of reference values for all spectra. With regard to precision, about 80% of the reported neutron results had single standard deviations within 10% at the means which indicates that precision is not a problem relative to accuracy for most participants. Average gamma results were greater than reference values by factors of 1.07 to 1.52 for the four exposures with TLD systems being more accurate than film. About 80% of all neutron results and 67% of all gamma results met regulatory standards for measurement accuracy and approximately 70% of all neutron data satisfied national dosimetry accreditation criteria for accuracy plus precision. In general, neutron dosimeter performance observed in this intercomparison was much improved compared to that observed in the prior studies while gamma dosimeter performance was about the same.
Book Synopsis 1982 US-CEC Neutron Personnel Dosimetry Intercomparison Study by : R. E. Swaja
Download or read book 1982 US-CEC Neutron Personnel Dosimetry Intercomparison Study written by R. E. Swaja and published by . This book was released on 1983 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Intercomparison of Personnel Dosimeters by :
Download or read book Intercomparison of Personnel Dosimeters written by and published by . This book was released on 1974 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An intercomparison of personnel monitoring dosimeters was conducted at Oak Ridge National Laboratory's DOSAR Facility. Ten independent laboratories and companies participated in an intercomparison of neutron and gamma-ray dosimeters used for routine personnel dosimetry. The dosimeters, which were sent through the mail, were exposed at the Health Physics Research Reactor to the same three ''standardized'' radiation fields which have been used for the past several years for intercomparing nuclear accident dosimeters. In addition, a 14-MeV neutron field was used as a fourth exposure condition. The results of the intercomparison show widely varying dose estimates. The reported values of neutron dose equivalent, for example, have standard deviations ranging from 47 to 102 percent of the mean. (auth).
Book Synopsis Personnel Dosimetry Intercomparison Study by : Oak Ridge National Laboratory
Download or read book Personnel Dosimetry Intercomparison Study written by Oak Ridge National Laboratory and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis 1989 neutron and gamma personnel dosimetry intercomparison study using RADCAL sources by : C. S. Sims
Download or read book 1989 neutron and gamma personnel dosimetry intercomparison study using RADCAL sources written by C. S. Sims and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
