Download or read book Thick Target Neutron Yields from Spallation Reactions written by Chalk River Nuclear Laboratories. Neutron and Solid State Physics Branch and published by Chalk River, Ont. : Neutron and Solid State Physics Branch, Chalk River Laboratories. This book was released on 1992 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thick Target Neutron Yields from Spallation Reactions written by Chalk River Nuclear Laboratories and published by . This book was released on 1992 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: For very high power accelerator-based transmutation systems, thermodynamic considerations dictate targets of 50-100 cm diameter and 125-250 cm length. The spallation neturon yields calculated for these larger size targets are about 50-55 neturons per proton of energy 1.6 GeV, which would appear to be counter to the experimental value of 35 neutrons per proton extrapolated from the Cosmotron data, or even the theoretical value of 40 n/p for the 20 cm diameter target used in the experiments. This paper examines the two possible causes for this discrepancy: proton beam leakage from Cosmotron targets or neutron multiplication.
Download or read book Thick target neutron yields and spectral distributions from the li 7 sup d sub p n and be 9 sup d sub p n reactions written by M. A. Lone and published by . This book was released on 1977 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comparison of alpha N Thick target Neutron Yields and Spectra from ORINGEN S and SOURCES written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Both ORIGEN-S and SOURCES generate thick-target neutron yields and energy spectra from ([alpha], n) reactions in homogeneous materials. SOURCES calculates yield and spectra for any material containing [alpha]-emitting and ([alpha], n) target elements by simulating reaction physics, using [alpha]-emission energy spectra, elemental stopping cross sections, ([alpha], n) cross sections for target nuclei, and branching fractions to produce-nuclide energy levels. This methodology results in accurate yield and spectra. ORIGEN-S has two options for calculating yields and spectra. The UO[sub 2] option (default) estimates yields and spectra assuming the input [alpha]-emitters to be infinitely dilute in UO[sub 2]. The borosilicate-glass option estimates yields from the total input material composition and generates spectra purportedly representative of spectra generated by [sup 238]Pu, [sup 241]Am, [sup 242]Cm, and [sup 244]Cm infinitely dilute in borosilicate glass, even if none of these four [alpha]-emitters are present in the input material composition. Because yields from the borosilicate-glass option in ORIGEN-S are based on entire input material composition and are reasonably accurate, the same is often assumed to be true for spectra. The input/output functionality of the borosilicate-glass option, along with ambiguity in ORIGEN-S documentation, gives the incorrect impression that spectra representative of input compositions are generated. This impression is reinforced by wide usage of the SCALE code system and its ORIGEN-S module and their sponsorship by the US Nuclear Regulatory Commission.
Download or read book Neutron yields from proton induced spallation reactions in thick targets of lead written by M. A. Lone and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A set of bundle rotation pressure drop measurements was made at spel with axial separations of up to 9.53 mm between the bundles. analysis of results shows that the average junction pressure drop is reduced by up to 2.5 percent for separation up to 4 mm. the mimimum junction pressure drop for aligned bundles increases continuously by 12 percent per mm of separation up to 9.52 mm, the largest separation tested.
Download or read book Thick target Neutron and gamma ray Yields Induced by Medium energy Proton and Deuteron Bombardments written by Lawrence Livermore Laboratory and published by . This book was released on 1979 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Double Differential Neutron Yields Produced by Proton Helium and Iron Interactions in Thick Aluminum Targets written by Natalie Ann McGirl and published by . This book was released on 2017 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent calculations of galactic cosmic ray (GCR) transport in enclosed, shielded space environments indicate that a minimum dose equivalent is achieved with aluminum shielding thicknesses near 20 g/cm2 [grams per centimeter squared]. Increases in the absorbed dose and dose equivalent with shielding thicknesses above 20 g/cm2 are believed to be caused by the production of light ions and neutrons in the thick shielding. However, uncertainties surround these calculations due to limited cross section and yield data for high-energy projectiles incident on thick targets. Thick-target neutron yields are particularly valuable measurements since they are produced over a wide range of energies by primary and secondary particles and include neutrons modified by transport through a material. Thus, a database of thick-target neutron yield measurements will help validate transport code calculations and quantify uncertainties between experimental and simulated data. In March 2016, secondary neutron yields from GCR-like projectiles impinging upon thick targets were measured at Brookhaven National Laboratory's NASA Space Radiation Laboratory. 400 and 800 AMeV [megaelectron volt per nucleon] iron and proton, and 400 AMeV helium projectiles were set incident upon 20, 40, and 60 g/cm2-thick aluminum targets, and a second 60 g/cm2 aluminum target was centered downstream to study backscattered neutrons at a later date. Upstream target neutron yields were measured with liquid scintillators at 10° [degrees], 30°, 45°, 60°, 80°, and 135° off the beam axis using the time-of-flight technique. Measurements were converted to double differential thick-target yields and compared with PHITS and MCNP transport model calculations. Comparisons with PHITS and MCNP revealed inconsistencies at low to intermediate energies, in addition to overestimations of the experimental yields at the 10° high-energy peak. Wide-angle yields at the shoulder energies were fairly well modeled for most systems, and yields at 135° were underestimated for the 400 AMeV projectile beams. Overall, both codes would benefit from improvements in their neutron production models, particularly below the peak or shoulder energies. This systematic study on secondary neutrons produced by thick-target interactions will be incorporated by NASA into a rigorous uncertainty quantification procedure, which will ultimately help determine optimal shielding thicknesses for future space applications.
Download or read book Thick Target Fast Neutron Yields written by Z. Y. Guo and published by . This book was released on 1987 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Calculation of Neutron Yields in Mixtures and Compounds from the Thick Target Alpha N Yields in the Separate Constituents written by D. West and published by . This book was released on 1979 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: A simple relation is derived between the thick target yield of neutrons produced following (alpha, n) reactions in compounds or homogeneous mixtures and the yields in the separate constituents. It is necessary to assume that the Bragg law of additivity of stopping powers holds for the compound and to make the approximation that the stopping powers of all materials vary with energy in the same way apart from constant factors. The range of validity of the second hypothesis is examined in some detail. It is shown to be far superior to the approximation of a stopping power independent of energy. (Author).
Download or read book Elements of Slow Neutron Scattering written by J. M. Carpenter and published by Cambridge University Press. This book was released on 2015-09-24 with total page 539 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive and up-to-date introduction to the fundamental theory and applications of slow-neutron scattering.
Download or read book Thick target neutron and ray yields induced by medium energy proton and deuteron bombardments written by Lawrence Livermore Laboratory and published by . This book was released on 1979 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Data for Science and Technology written by Syed M. Qaim and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1041 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the Proceedings of the International Conference on Nuclear Data for Science and Technology held at Jillich in May 1991. The conference was in a series of application oriented nuclear data conferences organized in the past under the auspices of the Nuclear Energy Agency-Nuclear Data Committee (NEANDC) and with the support of the Nuclear Energy Agency-Committee on Reactor Physics (NEACRP). It was the fIrst international conference on nuclear data held in Germany, with the scientific responsibility entrusted to the Institute of Nuclear Chemistry of the Research Centre Jillich. The scientific programme was established by the International Programme Committee in consultation with the International Advisers, and the NEA and IAEA cooperated in the organization. A total of 328 persons from 37 countries and fIve international organizations participated. The scope of these Proceedings extends to a wide range of interdisciplinary topics dealing with measu rement, calculation, evaluation and application of nuclear data, with a major emphasis on numerical data. Both energy and non-energy related applications are considered and due attention is given to some fundamental aspects relevant to the understanding of nuclear data.
Download or read book Neutron Sources written by Henry Herman Barschall and published by Pergamon. This book was released on 1983 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neutron Scattering Fundamentals written by Francisco J. Bermejo and published by Elsevier Inc. Chapters. This book was released on 2013-11-22 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: This chapter reviews the most significant developments that have taken place in the design, construction, and operation of new neutron sources as well as the refurbishment programs of others already serving the neutron-scattering community. Such advances in neutron production devices are to be considered in conjunction with impressive achievements in the optimization of neutron delivery systems as well as in neutron instrumentation which overall resulted in a truly remarkable improvement in neutron count rates. As a result, the capabilities of experimental neutron sources are nowadays larger than ever before, despite there being fewer sources available. It is also worth remarking the coming into line of compact, accelerator-driven neutron sources as well as work carried out at small research reactors which, as exemplified during the past decade, have played an important role in helping the large, user-based facilities to carry out development work geared toward the achievement of full performance.
Download or read book The Calculation of Neutron Yields in Mixtures and Compounds from the Thick Target w N Yields in the Separate Constituents written by D. West and published by . This book was released on 1979 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Calculation of Neutron Yields in Mixtures and Compounds from the Thick Target alpha n Yields in the Seperate Constituents written by D. West and published by . This book was released on 1979 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of Thick target Neutron Emission from Be 9 d N B 10 at E written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Double-differential measurements of neutron emission from a thick beryllium target bombarded with 7-MeV deuterons are made for neutrons above 800 keV, over the angular range of 0 to 155°. The angular dependence of the neutron yield is found to be quite anisotropic. The importance of this anisotropy in integral neutron-induced reaction cross-section investigations is illustrated. 7 refs.,
