Download or read book Directional Fast Neutron Detection Using a Time Projection Chamber written by and published by . This book was released on 2010 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Directional Detection of Fast Neutrons Using a Time Projection Chamber written by and published by . This book was released on 2009 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spontaneous fission in Special Nuclear Material (SNM) such as plutonium and highly enriched uranium (HEU) results in the emission of neutrons with energies in the MeV range (hereafter 'fast neutrons'). These fast neutrons are largely unaffected by the few centimeters of intervening high-Z material that would suffice for attenuating most emitted gamma rays, while tens of centimeters of hydrogenous materials are required to achieve substantial attenuation of neutron fluxes from SNM. Neutron detectors are therefore an important complement to gamma-ray detectors in SNM search and monitoring applications. The rate at which SNM emits fast neutrons varies from about 2 per kilogram per second for typical HEU to some 60,000 per kilogram per second for metallic weapons grade plutonium. These rates can be compared with typical sea-level (cosmogenic) neutron backgrounds of roughly 5 per second per square meter per steradian in the relevant energy range [1]. The fact that the backgrounds are largely isotropic makes directional neutron detection especially attractive for SNM detection. The ability to detect, localize, and ultimately identify fast neutron sources at standoff will ultimately be limited by this background rate. Fast neutrons are particularly well suited to standoff detection and localization of SNM or other fast neutrons sources. Fast neutrons have attenuation lengths of about 60 meters in air, and retain considerable information about their source direction even after one or two scatters. Knowledge of the incoming direction of a fast neutron, from SNM or otherwise, has the potential to significantly improve signal to background in a variety of applications, since the background arriving from any one direction is a small fraction of the total background. Imaging or directional information therefore allows for source detection at a larger standoff distance or with shorter dwell times compared to nondirectional detectors, provided high detection efficiency can be maintained. Directional detection of neutrons has been previously considered for applications such as controlled fusion neutron imaging [2], nuclear fuel safety research [3], imaging of solar neutrons and SNM [4], and in nuclear science [5]. The use of scintillating crystals and fibers has been proposed for directional neutron detection [6]. Recently, a neutron scatter camera has been designed, constructed, and tested for imaging of fast neutrons, characteristic for SNM material fission [7]. The neutron scatter camera relies on the measurement of the proton recoil angle and proton energy by time of flight between two segmented solid-state detectors. A single-measurement result from the neutron scatter camera is a ring containing the possible incident neutron direction. Here we describe the development and commissioning of a directional neutron detection system based on a time projection chamber (TPC) detector. The TPC, which has been widely used in particle and nuclear physics research for several decades, provides a convenient means of measuring the full 3D trajectory, specific ionization (i.e particle type) and energy of charged particles. For this application, we observe recoil protons produced by fast neutron scatters on protons in hydrogen or methane gas. Gas pressures of a few ATM provide reasonable neutron interaction/scattering rates.
Download or read book Directional Fast neutron Detectors written by R. C. Byrd and published by . This book was released on 1992 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book CALIBRATION AND TESTING OF A LARGE AREA FAST NEUTRON DIRECTIONAL DETECTOR written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have developed a new directional fast-neutron detector based on double proton recoil in two separated planes of plastic scintillators with position-sensitive readout. This method allows the energy spectrum of the neutrons to be measured by a combination of peak amplitude in the first plane and time of flight to the second plane. The planes are made up of 1-m long, 10-cm high paddles with photomultipliers at both ends, so that the location of an event along the paddle can be estimated from the time delay between the optical pulses detected at the two ends. The direction of the scattered neutron can be estimated from the locations of two time-correlated events in the two planes, and the energy lost in the first scattering event can be estimated from the pulse amplitude in the first plane. The direction of the incident neutron can then be determined to lie on a cone whose angle is determined by the kinematic equations. The superposition of many such cones generates an image that indicates the presence of a localized source. Setting upper and lower limits on the time of flight allows discrimination between gamma rays, muons and neutrons. Monte Carlo simulations were performed to determine the expected angular resolution and efficiency. These models show that the lower energy limit for useful directional events is about 100 keV, because lower energy neutrons are likely to scatter more than once in the first plane. Placing a shadow bar in front of the detector provides an alternative way to obtain the direction to a point source, which may require fewer events. This method also can provide dual capability as a directional gamma detector.
Download or read book A Time Projection Chamber for High Resolution Fast Neutron Imaging of Missile Warheads written by and published by . This book was released on 2011 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Imaging the Ionization Track of Alpha Recoils for the Directional Detection of Weapons Grade Plutonium written by William Lawrence Koch and published by . This book was released on 2013 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the dawn of the nuclear weapons era, political, military, and scientific leaders around the world have been working to contain the proliferation of Special Nuclear Material and explosively fissile material. This paper describes the construction of a prototype, directional, fast neutron detector, modeled after the Dark Matter Time Projection Chamber. Fast neutrons are emitted by a host of interesting sources, including medical isotopes, research sources, cosmic neutron spallation, and the most interesting, SNM and WGP. This detector was built for remote operations using a computer terminal for the detection of Special Nuclear Material (SNM) and Weapons Grade Plutonium (WGP). Further, this paper discusses the baseline and characterization testing using a low intensity Americium-Beryllium neutron source, compared with probability-based rate calculations and Geant4 simulation rates. The detector, in its current configuration agrees well with the expected rates, showing a 95% track reconstruction efficiency, computed from both the probability-based rate calculation and the Geant4 simulation rates. Scaling this to an appropriate size, this detector provides an entirely unique and new piece of information in the world of radiation detection: direction to fast neutron source. The primary concept of employment focuses on building statistics through large total cross section, increased scan time, or proximity of scan source. With these three variables balanced for a specific operational environment, this detector technology is able to pinpoint fast neutron sources in a wide variety of scenarios.
Download or read book DESIGN OF A LARGE AREA FAST NEUTRON DIRECTIONAL DETECTOR written by P. E. VANIER and published by . This book was released on 2006 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: A large-area fast-neutron double-scatter directional detector and spectrometer is being constructed using l-meter-long plastic scintillator paddles with photomultiplier tubes at both ends. The scintillators detect fast neutrons by proton recoil and also gamma rays by Compton scattering. The paddles are arranged in two parallel planes so that neutrons can be distinguished from muons and gamma rays by time of flight between the planes. The signal pulses are digitized with a time resolution of one gigasample per second. The location of an event along each paddle can be determined from the relative amplitudes or timing of the signals at the ends. The angle of deflection of a neutron in the first plane can be estimated from the energy deposited by the recoil proton, combined with the scattered neutron time-of-flight energy. Each scattering angle can be back-projected as a cone, and many intersecting cones define the incident neutron direction from a distant point source. Moreover, the total energy of each neutron can be obtained, allowing some regions of a fission source spectrum to be distinguished from background generated by cosmic rays. Monte Carlo calculations will be compared with measurements.
Download or read book Two Techniques for Fast Neutron Detection Using the S32 n P P32 Reaction written by R. L. Tomlinson and published by . This book was released on 1955 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of a Directional Detector for Fast Neutrons written by Gerard M. Lebreton and published by . This book was released on 1960 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Directional Neutron Detectors for Use with 14 MeV Neutrons written by Duane A. Sunnarborg and published by . This book was released on 2005 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current Joint Test Assembly (JTA) neutron monitors rely on knock-on proton type detectors that are susceptible to X-rays and low energy gamma rays. We investigated two novel plastic scintillating fiber directional neutron detector prototypes. One prototype used a fiber selected such that the fiber width was less than 2.1mm which is the range of a proton in plastic. The difference in the distribution of recoil proton energy deposited in the fiber was used to determine the incident neutron direction. The second prototype measured both the recoil proton energy and direction. The neutron direction was determined from the kinematics of single neutron-proton scatters. This report describes the development and performance of these detectors.
Download or read book Methods and Instruments for Fast Neutron Detection written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Pacific Northwest National Laboratory evaluated the performance of a large-area (0̃.7 m2) plastic scintillator time-of-flight (TOF) sensor for direct detection of fast neutrons. This type of sensor is a readily area-scalable technology that provides broad-area geometrical coverage at a reasonably low cost. It can yield intrinsic detection efficiencies that compare favorably with moderator-based detection methods. The timing resolution achievable should permit substantially more precise time windowing of return neutron flux than would otherwise be possible with moderated detectors. The energy-deposition threshold imposed on each scintillator contributing to the event-definition trigger in a TOF system can be set to blind the sensor to direct emission from the neutron generator. The primary technical challenge addressed in the project was to understand the capabilities of a neutron TOF sensor in the limit of large scintillator area and small scintillator separation, a size regime in which the neutral particle's flight path between the two scintillators is not tightly constrained.
Download or read book Palladium Film Fast Neutron Detector written by Ben Roger Gossick and published by . This book was released on 1949 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Fission written by Patrick Talou and published by Springer Nature. This book was released on 2023-01-01 with total page 487 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides advanced students and postdocs, as well as current practitioners of any field of nuclear physics involving fission an understanding of the nuclear fission process. Key topics covered are: fission cross sections, fission fragment yields, neutron and gamma emission from fission and key nuclear technologies and applications where fission plays an important role. It addresses both fundamental aspects of the fission process and fission-based technologies including combining quantitative and microscopic modeling.
Download or read book A Standardization of the Hurst Radsan Neutron Detector written by A. H. Redmond and published by . This book was released on 1962 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fast Neutron Detection with a Neutron Scatter Camera written by and published by . This book was released on 2011 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Literature Search on Neutron Detectors written by Frances L. Sachs and published by . This book was released on 1951 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book State Of The Art Of Neutrino Physics The A Tutorial For Graduate Students And Young Researchers written by Antonio Ereditato and published by World Scientific. This book was released on 2018-03-23 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: The neutrino is the most fascinating elementary particle due to its elusive nature and outstanding properties that have attracted the interest of generations of physicists since 1930, when it was first postulated by Wolfgang Pauli as a 'desperate remedy' to explain the apparent energy violation in the beta decay. Many fundamental discoveries in particle physics had the neutrino involved in one way or another. To date, neutrino physics is still one of the hottest topics of modern particle physics. Key experiments and significant theoretical developments have contributed in building up what we can call now the Standard Model of Neutrino Physics.The aim of the book is to provide graduate students and young researchers a comprehensive tutorial in modern neutrino physics, specially tailored with emphasis on the educational aspects. It provides an overview of the basics and of recent achievements in the field, from both experimental and theoretical points of view.
