Download or read book The Measurement of 14 MeV Neutron Fluxes from a Neutron Generator Laboratory Method written by and published by . This book was released on 1969 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 14 MeV neutron flux is determined from the irradiation of a copper disc. A multi-channel analyser is used for the counting of the 0,511 MeV annihilation radiation emitted by the (62)Cu isotope. This isotope results from the reaction (63)Cu(n,2n)(62)Cu. The flux is quoted both as disintegrations per minute per gram of copper and as neutrons per square centimetre per second, and the size of the copper disc is given. It is important for both forms to be used because, although the second form is physically more meaningful, its value depends on the value used for the cross-section of the reaction, and that is not accurately known.

Download or read book Measurement of Neutron Flux and Spectra for Physical and Biological Applications written by National Committee on Radiation Protection and Measurements (U.S.) and published by . This book was released on 1960 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurement of Neutron Flux and Spectra for Physical and Biological Applications written by National Committee on Radiation Protection and Measurements (U.S.) and published by . This book was released on 1960 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 14 MeV Neutrons written by Vladivoj Valkovic and published by CRC Press. This book was released on 2015-08-25 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the often difficult and time-consuming effort of performing experiments with fast (14 MeV) neutrons, these neutrons can offer special insight into nucleus and other materials because of the absence of charge. 14 MeV Neutrons: Physics and Applications explores fast neutrons in basic science and applications to problems in medicine, the envir

Download or read book Handbook of Fast Neutron Generators Volume I written by Julius Csikai and published by CRC Press. This book was released on 1987-09-30 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook reviews those problems and methods of science and technology where the neutrons produced in the 3H/d, N/4He, and 2H/d, n/3He reactions play the main role. This two-volume set: Discusses possible applications of these small generators as thermal neutron sources Enables suitable topics to be selected for education and training, provides a wide range of experiments with the detection of neutrons and charged particles, including the study of shielding and the generator technology itself Gives a review of important operational characteristics of neutron generators and the necessary instruments connected with these applications Provides an account of recent results of fast neutron activation analysis in various fields.

Download or read book 14 MeV Neutron Generator Used as a Thermal Neutron Source written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most important applications of the general purpose Monte Carlo N-Particle (MCNPS and MCNPX) codes is neutron shielding design. We employed this method to simulate the shield of a 14-MeV neutron generator used as a thermal neutron source providing an external thermal neutron beam for testing large area neutron detectors developed for diffraction studies in biology and also useful for national security applications. Nuclear reactors have been the main sources of neutrons used for scientific applications. In the past decade, however, a large number of reactors have been shut down, and the importance of other, smaller devices capable of providing neutrons for research has increased. At Brookhaven National Laboratory a moderated Am-Be neutron source with shielding is used for neutron detector testing. This source is relatively weak, but provides a constant flux of neutrons, even when not in use. The use of a 14 MeV energized neutron generator, with an order of magnitude higher neutron flux has been considered to replace the Am-Be source, but the higher fast neutron yield requires a more careful design of moderator and shielding. In the present paper we describe a proposed shielding configuration based on Monte Carlo calculations, and provide calculated neutron flux and dose distributions. We simulated the neutron flux distribution of our existing Am-Be source surrounded by a paraffin thermalizer cylinder (radius of 17.8 cm), 0.8 mm cadmium, and borated polyethylene as biological shield. The thermal neutrons are available through a large opening through the polyethylene and cadmium. The geometrical model for the MCNPS and MCNPX2 simulations is shown in Fig. 1. We simulated the Am-Be source neutron energy distribution as a point source having an energy distribution of four discrete lines at 3.0 (37%), 5.0 (35%), 8.0 (20%) and 11.0 (8%) MeV energies. The estimated source strength based on the original specifications is 6.6 · 106 neutrons/sec. The simulation accurately predicts the measured thermal neutron flux at the collimator (Figure 2), thus providing validation for this method. Using MCNPX we simulated the neutron and photon dose distribution and also obtained a good agreement with the measured values. Having established a validated framework for the shield calculation we then scaled up the Am-Be arrangement to simulate the shielding required for the higher neutron energy and flux of the neutron generator ( -108 neutrodsec at 14 MeV). Given the physical dimensions of the generator we have chosen a cylindrical geometry, where the generator tube is placed vertically into a cylindrical thermalizer (25 cm paraffin) from above. The thermalizer is surrounded by 0.8 mm cadmium, and a cylindrical borated polyethylene shield. A cylindrical opening (radius of 7.6 cm) serves to direct the neutrons out towards the experimental area (on the right side). The initial model is shown in figure 3. The first goal of the calculations was to establish the minimal required radius of the biological shield. For this purpose we performed MCNPX neutron and photon dose distribution calculations by tallying the absorbed dose on a 200 x 200 cm mesh in the vertical center plane superimposed over the geometry. Figure 4. displays the neutron dose distribution along the central horizontal (X) axis. As observed from the figure, a shielding radius of -80 cm is sufficient to obtain a dose level of

Download or read book 14 MeV Neutrons written by Vladivoj Valkovic and published by CRC Press. This book was released on 2015-08-18 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: 14 MeV neutrons, or fusion neutrons, have more energy than other neutrons (10 times more than fission neutrons) and, as such, offer unique advantages in various industrial uses. This book gives a detailed account of neutron activation for threat material detection such as in landmines, packaged explosives and cargo containers, as well as under extreme conditions, including underwater and in space. It also provides extensive treatment of neutron logging for oil industry applications, neutron radiography and other medical applications.

Download or read book Flux and Spectral Measurements of Primary and Moderated Neutron Sources written by E. Tochilin and published by . This book was released on 1962 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radioactive (a, n) neutron sources include Ra-Be, PuF4, and four PuBe13 sources. Comparative neutron emission rates were determined by two separate methods: (1) the manganese sulfate bath with appropriate corrections made for fast neutron escape or capture and for thermal neutron capture by the source; and (2) long counter measurements corrected for energy response and so rce anisotropy. Agreement to within 1 percent was obtained by the two independent methods. A Ra-Be source calibrated against the NBS neutron standard was used as a primary reference Spectral measurements of PuBe13 and PuF4 neutron sources were made with nuclear emulsions. By the use of cylindrical plastic and lead absorbers, an effort was made to moderate the PuBe13 spectrum and thereby obtain additional calibration points for instrument response studies. Spectral changes were initially studied with the doublemoderator technique, followed by later measurements with nuclear emulsions. From flux and spectral measurements of the primary and moderated radioactive sources, the first collision tissue dose was calculated and, in turn, compared to experimental measurements of absorbed dose with proportional counters designed according to the Bragg-Gray principle. (Author).

Download or read book Measurement of Neutron Flux and Spectra for Physical and Biological Applications written by United States. National Committee on Radiation Protection and Measurements and published by . This book was released on 1960 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 14 MeV Neutron Generator Dose Modeling written by Kristen Alycia McConnell and published by . This book was released on 2013 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling and understanding the doses around the neutron generator provides insightful data in regard to radiation safety and protection precautions. Published data can be used to predict doses, but realistic data for the Nuclear Engineering Teaching Laboratory's Thermo MP 320 Neutron Generator helps health physicists more accurately predict dose rates and protect experimenters against exposure. The goal was to create a model inclusive of the entire setup and room where the neutron generator is housed. Monte Carlo N-Particle (MCNP) Code reigns as the preferred method for modeling radiation transport and was utilized to model the transport of neutrons within the current configuration of the 14 MeV neutron generator facility. This model took into account all shielding materials and their respective dimensions and locations within the concrete room. By utilizing tallies and tally modifiers, the model predicts dose rates that can be used with experimental factors such as irradiation time and flux to predict a dose in millirem. Validation experiments were performed in the current setup using Landauer Luxel®+ with Neutrak dosimeters placed in strategic locations to record the neutron dose vi received as well as a Ludlum Model 42-41 PRESCILA neutron probe to predict dose rates. The dosimeters and PRESCILA measurement locations matched the positions of the point detector tallies in MCNP. After laboratory analysis, a comparison was performed between the model output and the dosimeter and PRESCILA values to successfully validate the accuracy of the model.

Download or read book Measurement of Neutron Flux and Spectra for Physical and Biological Applications written by National Committee on Radiation Protection and Measurements (U.S.) and published by . This book was released on 1960 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Two plate Method of Measuring Fast Neutron Energy Spectra when the Direction of the Incident Neutrons Cannot be Determined written by John E. Evans and published by . This book was released on 1952 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Summary of Neutron Measurement Methods written by Herman Lunden Miller and published by . This book was released on 1962 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Neutron Generators for Analytical Purposes written by International Atomic Energy Agency and published by IAEA Radiation Technology Repo. This book was released on 2012 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication addresses recent developments in neutron generator (NG) technology. It presents information on compact instruments with high neutron yield to be used for neutron activation analysis (NAA) and prompt gamma neutron activation analysis in combination with high count rate spectrometers. Traditional NGs have been shown to be effective for applications including borehole logging, homeland security, nuclear medicine and the on-line analysis of aluminium, coal and cement. Pulsed fast thermal neutron analysis, as well as tagged and timed neutron analysis, are additional techniques which can be applied using NG. Furthermore, NG can effectively be used for elemental analysis and is also effective for analysis of hidden materials by neutron radiography. Useful guidelines for developing NG based research laboratories are also provided in this publication.

Download or read book A Measurement of the Differential Cross Section for Elastic Scattering of 14 MeV Neutrons in Niobium written by Nestor Constantinos Tsirliganis and published by . This book was released on 1995 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Adaptation of the 14 MeV Neutron Generator to the Measurements of Neutron Spectra by Time of Flight Technique written by Jerzy Januszewski and published by . This book was released on 1962 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Absolute Neutron Flux Measurements of a D T Neutron Generator written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: