2,766 research outputs found

    Integration of external and internal dosimetry in Switzerland

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    Individual monitoring regulations in Switzerland are based on the ICRP60 recommendations. The annual limit of 20 mSv for the effective dose applies to the sum of external and internal radiation. External radiation is monitored monthly or quarterly with TLD, DIS or CR-39 dosemeters by 10 approved external dosimetry services and reported as Hp(10) and Hp(0.07). Internal monitoring is done in two steps. At the workplace, simple screening measurements are done frequently in order to recognise a possible incorporation. If a nuclide dependent activity threshold is exceeded then one of the seven approved dosimetry services for internal radiation does an incorporation measurement to assess the committed effective dose E50. The dosimetry services report all the measured or assessed dose values to the employer and to the National Dose Registry. The employer records the annually accumulated dose values into the individual dose certificate of the occupationally exposed person, both the external dose Hp(10) and the internal dose E50 as well as the total effective dose E = Hp(10)+E50. Based on the national dose registry an annual report on the dosimetry in Switzerland is published which contains the statistics for the total effective dose, as well as separate statistics for external and internal exposur

    Probing the boundaries of the Hadronic Phase through a Strangeness including Statistical Bootstrap Model (S-SBM)

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    A recently constructed strangeness-including Statistical Bootstrap Model (S-SBM), which defines the limits of the hadronic phase and provides for a phase beyond, is further extended so as to include a factor that describes strangeness suppression. The model is then used to analyse the multiplicity data from collision experiments in which the colliding entities form isospin symmetric systems, the primary focus being on S+S interactions (NA35 collaboration). An optimal set of thermodynamical variables is extracted through a fit to both the inclusive full phase space and midrapidity data. The assumption that the measured particles originate from a thermally and partial-chemically equilibrated source described by the S-SBM is satisfactorily established. The proximity of the thermodynamical variables extracted from the S+S data to the limits of the hadronic phase is systematically investigated. Finally, experimental data from proton-antiproton collisions (UA5 collaboration) are similarly analysed.Comment: 39 pages, 17 figures, all the figures joined in one file. Submitted in Phys. Rev.

    Environmental changes and violent conflict

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    This letter reviews the scientific literature on whether and how environmental changes affect the risk of violent conflict. The available evidence from qualitative case studies indicates that environmental stress can contribute to violent conflict in some specific cases. Results from quantitative large-N studies, however, strongly suggest that we should be careful in drawing general conclusions. Those large-N studies that we regard as the most sophisticated ones obtain results that are not robust to alternative model specifications and, thus, have been debated. This suggests that environmental changes may, under specific circumstances, increase the risk of violent conflict, but not necessarily in a systematic way and unconditionally. Hence there is, to date, no scientific consensus on the impact of environmental changes on violent conflict. This letter also highlights the most important challenges for further research on the subject. One of the key issues is that the effects of environmental changes on violent conflict are likely to be contingent on a set of economic and political conditions that determine adaptation capacity. In the authors' view, the most important indirect effects are likely to lead from environmental changes via economic performance and migration to violent conflict. © 2012 IOP Publishing Ltd

    Study of the impact of tissue density heterogeneities on 3-dimensional abdominal dosimetry: comparison between dose kernel convolution and direct monte carlo methods.

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    Dose kernel convolution (DK) methods have been proposed to speed up absorbed dose calculations in molecular radionuclide therapy. Our aim was to evaluate the impact of tissue density heterogeneities (TDH) on dosimetry when using a DK method and to propose a simple density-correction method. METHODS: This study has been conducted on 3 clinical cases: case 1, non-Hodgkin lymphoma treated with (131)I-tositumomab; case 2, a neuroendocrine tumor treatment simulated with (177)Lu-peptides; and case 3, hepatocellular carcinoma treated with (90)Y-microspheres. Absorbed dose calculations were performed using a direct Monte Carlo approach accounting for TDH (3D-RD), and a DK approach (VoxelDose, or VD). For each individual voxel, the VD absorbed dose, D(VD), calculated assuming uniform density, was corrected for density, giving D(VDd). The average 3D-RD absorbed dose values, D(3DRD), were compared with D(VD) and D(VDd), using the relative difference Δ(VD/3DRD). At the voxel level, density-binned Δ(VD/3DRD) and Δ(VDd/3DRD) were plotted against ρ and fitted with a linear regression. RESULTS: The D(VD) calculations showed a good agreement with D(3DRD). Δ(VD/3DRD) was less than 3.5%, except for the tumor of case 1 (5.9%) and the renal cortex of case 2 (5.6%). At the voxel level, the Δ(VD/3DRD) range was 0%-14% for cases 1 and 2, and -3% to 7% for case 3. All 3 cases showed a linear relationship between voxel bin-averaged Δ(VD/3DRD) and density, ρ: case 1 (Δ = -0.56ρ + 0.62, R(2) = 0.93), case 2 (Δ = -0.91ρ + 0.96, R(2) = 0.99), and case 3 (Δ = -0.69ρ + 0.72, R(2) = 0.91). The density correction improved the agreement of the DK method with the Monte Carlo approach (Δ(VDd/3DRD) < 1.1%), but with a lesser extent for the tumor of case 1 (3.1%). At the voxel level, the Δ(VDd/3DRD) range decreased for the 3 clinical cases (case 1, -1% to 4%; case 2, -0.5% to 1.5%, and -1.5% to 2%). No more linear regression existed for cases 2 and 3, contrary to case 1 (Δ = 0.41ρ - 0.38, R(2) = 0.88) although the slope in case 1 was less pronounced. CONCLUSION: This study shows a small influence of TDH in the abdominal region for 3 representative clinical cases. A simple density-correction method was proposed and improved the comparison in the absorbed dose calculations when using our voxel S value implementation

    J/Psi suppression in colliding nuclei: statistical model analysis

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    We consider the J/ΨJ/\Psi suppression at a high energy heavy ion collision. An ideal gas of massive hadrons in thermal and chemical equilibrium is formed in the central region. The finite-size gas expands longitudinally in accordance with Bjorken law. The transverse expansion in a form of the rarefaction wave is taken into account. We show that J/ΨJ/\Psi suppression in such an environment, when combined with the disintegration in nuclear matter, gives correct evaluation of NA38 and NA50 data in a broad range of initial energy densities.Comment: 14 pages, 13 figures. Accepted for publication in Phys. Rev.

    The First 1 1/2 Years of TOTEM Roman Pot Operation at LHC

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    Since the LHC running season 2010, the TOTEM Roman Pots (RPs) are fully operational and serve for collecting elastic and diffractive proton-proton scattering data. Like for other moveable devices approaching the high intensity LHC beams, a reliable and precise control of the RP position is critical to machine protection. After a review of the RP movement control and position interlock system, the crucial task of alignment will be discussed.Comment: 3 pages, 6 figures; 2nd International Particle Accelerator Conference (IPAC 2011), San Sebastian, Spain; contribution MOPO01

    Sub MeV Particles Detection and Identification in the MUNU detector ((1)ISN, IN2P3/CNRS-UJF, Grenoble, France, (2)Institut de Physique, Neuch\^atel, Switzerland, (3) INFN, Padova Italy, (4) Physik-Institut, Z\"{u}rich, Switzerland)

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    We report on the performance of a 1 m3^{3} TPC filled with CF4_{4} at 3 bar, immersed in liquid scintillator and viewed by photomultipliers. Particle detection, event identification and localization achieved by measuring both the current signal and the scintillation light are presented. Particular features of α\alpha particle detection are also discussed. Finally, the 54{54}Mn photopeak, reconstructed from the Compton scattering and recoil angle is shown.Comment: Latex, 19 pages, 20 figure

    DEMONSTRATION OF THE DOE INTERIM ENERGY CONSERVATION STANDARDS FOR NEW FEDERAL RESIDENTIAL BUILDINGS

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    In accordance with federal legislation, the U.S. Department of Energy (DOE) has sponsored a study to demonstrate use of its Interim Energy Conservation Standards for New Federal Residential Buildings. The demonstration study was conducted by DOE and the Pacific Northwest Laboratory (PNL). The demonstration is the second step in a three-step process: I) development of interim standards, 2) demonstration of the interim standards, and 3) development of final standards. The standards are mandatory for federal agency housing procurements. Nevertheless, PNL found at the start of the demonstration that agency use of the interim standards had been minimal. The purpose of the standards is to improve the energy efficiency of federal housing and increase the use of nondepletable energy sources. In accordance with the legislation, the standards were to be performance-based rather than prescribing specific energy conservation measures. To fulfill this aspect of the legislation, the standards use a computer software program called COSTSAFR which generates a point system that individualizes the standards to specific projects based on climate, housing type, and fuel costs. The standards generate minimum energy-efficiency requirements by applying the life-cycle cost methodology developed for federal projects. For the demonstration, PNL and DOE chose five federal agency housing projects which had been built in diverse geographic and climate regions. Participating agencies were the Air Force, the Army (which provided two case studies), the Navy, and the Department of Health and Human Services. PNL worked with agency housing procurement officials and designers/architects to hypothetically apply the interim standards to the procurement and design of each housing project. The demonstration started at the point in the project where agencies would establish their energyefficiency requirements for the project and followed the procurement process through the designers' use of the point system to develop a design which would comply with the standards. PNL conducted extensive interviews with the federal agencies and design contractors to determine what impacts the standards would have on the existing agency procurement process as well as on designers. Overall, PNL found that the interim standards met the basic intent of the law. Specific actions were identified, however, that DOE could take to improve the standards and encourage the agencies to implement them. Agency personnel found the minimum efficiency levels established by the standards to be lower than expected, and lower than their existing requirements. Generally, this was because the standards factor in fuel costs, as well as energy savings due to various conservation measures such as insulation, when they determine the minimum efficiency levels required. The demonstration showed that federal agencies often pay low prices for heating fuel and electricity; these lower costs "tipped the scales," allowing designers to meet the efficiency target with designs that were relatively inefficient. It appeared, however, that the low prices paid by agencies directly to suppliers did not capture the agencies' full costs of providing energy, such as the costs of distribution and storage. Agency personnel expressed some concern about the standards' ability to incorporate new energy-efficient technologies and renewable resource technologies like solar heating systems. An alternative compliance procedure was developed to incorporate new technologies; however, demonstration participants said the procedure was not well documented and was difficult and time consuming to use. Despite these concerns, most agency personnel thought that the standards would fit into current procurement procedures with no big changes or cost increases. Many said use of the standards would decrease the time and effort they now spend to establish energy-efficiency requirements and to confirm that proposed designs comply. Personnel praised the software and documentation for being easy to use and providing energy efficiency requirements in energy dollars. Personnel were concerned about how the standards could be modified to analyze unusual design features. A centralized information source for agencies using the standards was suggested. Housing designers agreed that the DOE standards were easy to use to determine that their designs meet energy efficiency goals. They noted that the information provided by the standards could be useful in their design process. Most designers agreed with agency personnel that the alternative compliance procedure was too time consuming. They suggested that assistance be available so that the proposal and procurement process would not be interrupted. Additional conclusions were that training and assistance is needed by field office personnel because much of the federal agency procurement activity occurs at the field offices. Agency training needs fall into three categories: 1) specific improvements in the documentation, 2) materials and courses to educate users, and 3) mechanisms for providing information to users. Designers will need additional help, particularly in understanding how to design housing with improved energy-efficiency. A procedure to update the standards will be needed. DOE has met its legal requirement for obtaining public input but successful implementation of the standards will depend on mechanisms for continued public, industry, and agency feedback. Based on the demonstration, PNL recommends establishing task forces that will actively involve agency personnel and others in future revisions and development of the final standards. PNL also recommends that agencies use fuel and energy prices in the standards that reflect total costs better than the direct fuel prices that the agencies pay their suppliers. A number of ways are recommended to improve communications and the tools for implementing the standards. Several recommendations are made for increasing the number of renewable resource options that are included in the standards. Finally, PNL recommends on-going monitoring activities to continue to identify ways in which the standards can be improved

    DEMONSTRATION OF THE DOE INTERIM ENERGY CONSERVATION STANDARDS FOR NEW FEDERAL RESIDENTIAL BUILDINGS: EXECUTIVE SUMMARY

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    In accordance with federal legislation, the U.S. Department of Energy (DOE) bas conducted a project to demonstrate use of its Interim Energy Conservation Standards for New Federal Residential Buildings. The demonstration is the second step in a three-step process: development of interim standards, demonstration of the interim standards, and development of final standards. Pacific Northwest Laboratory (PNL) collected information from the demonstration project and prepared this report under a contract with DOE. The purpose of the standards is to improve the energy efficiency of federal housing and increase the use of nondepletable energy sources. In accordance with the legislation, the standards were to be performance-based rather than prescribing specific energy conservation measures. The standards use a computer software program called COSTSAFR which individualizes the standards based on climate, housing type, and fuel costs. The standards generate minimum energy-efficiency requirements by applying the life-cycle cost methodology developed for federal projects, For the demonstration, the DOE chose live federal agency housing projects: four military housing projects and one project for the Department of Health and Human Services. DOE and PNL worked with agency housing procurement officials and designers/architects to hypothetically apply the interim standards to each housing project. PNL conducted extensive interviews with the federal agencies and design contractors to determine what impacts the standards would have on the existing agency procurement process as well as on designers. Overall, PNL found that the interim standards met the basic intent of the law. Specific actions were identified, however, that DOE could take to improve the standards and encourage the agencies to implement them. Agency personnel and designers expressed similar concerns about the standards: the minimum efficiency levels established by the standards were lower than expected and the standards did not provide an easy way to incorporate new energy-efficient and renewable resource tec.:hnolog:ies like solar heating systems. Agency personnel said the standards would fit into current procurement procedures with no big changes or cost increases, Many said the standards would decrease the time and effort they now spend to establish energy-efficiency requirements and to confirm that proposed designs comply with those requirements. Agency personnel praised the software and documentation for being easy to use and providing energy-efficiency requirements in energy dollars. Housing designers agreed that the DOE standards were easy to use to determine that their designs meet energy-efficiency goals. Many felt the information provided by the standards could be useful in the design process. Based on the demonstration, PNL recommends establishing task forces that will actively involve agency personnel and others in future revisions and development of the final standards. PNL also recommends that DOE and federal agencies investigate the use of market fuel and energy prices in the standards, rather than the prices paid by the agencies, to better reflect actual costs. A number of recommendations are made for improving communications between DOE and the users of the standards and for enhancing tools to implement the standards. Several recommendations are made for increasing the number of renewable resources that are included in the standards. Finally, PNL recommends ongoing monitoring activities to continue to identify ways in which the standards can be improved
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