Download or read book Characterization of a Neutron Imaging Platform Utilizing a Compact Electronic Neutron Generator for Evaluation of Analog and Digital Neutron Imaging Methods and Techniques written by Michael James Taylor and published by . This book was released on 2019 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unlike X-Rays that interact strongly with the electron cloud surrounding atoms, neutrons interact very weakly with these electrons, but quite strongly with the nucleus of the atom. X-Rays follow a nearly linear trend of decreasing transmission as the atomic number of the element increases. Neutrons follow no such behavior and certain isotopes of elements such as lithium, boron, cadmium, and gadolinium interact very strongly with neutrons, unlike dense elements such as lead or tungsten. This gives neutrons a unique probing capability where X-Rays do not suffice. Neutron imaging is widely used in the commercial sector for munitions and critical aerospace component inspection as well as in the research realm for biological forensics, cultural heritage providence studies, and capturing repetitive processes such as cyclical fluid motion in rotating motors. Current neutron sources are typically nuclear reactors and spallation sources that provide incredibly high neutron yields and flux for the images, leading to reduced image times and/or high spatial resolution as well as new imaging techniques such as computed tomography, polarized neutron imaging, and phase contrast imaging. However, such sources are very expensive, require thorough regulatory oversight, and pose biological hazards from spent nuclear materials. Smaller sources such as sealed tube deuterium-deuterium or deuterium-tritium sources can allow for in-field inspection at a fraction of the cost of a reactor, but don't necessarily provide fast image acquisitions or adequate image quality. This thesis explores a system that is intended to fill the space between weak portable devices and strong, costly, immobile ones. An accelerator-based neutron generator has been designed and manufactured by Phoenix LLC in Madison, WI. This system operates on the principle of deuterium-deuterium fusion, which releases a free 2.45MeV (nominal) neutron in the fusion process. The system can be installed and commissioned in different locations throughout its lifetime and provides for in-field or commercial inspection of components. It has a neutron yield several orders of magnitude higher than sealed-tube neutron sources. The goal herein was to: enhance the performance of the neutron generator through careful beamline design from the source to the target to obtain the maximum neutron yield, optimize the geometry of the neutron moderator and collimator to maximize the imaging metrics of a thermalized and collimated neutron beam free of background gamma and fast neutron radiation contamination, and find efficient neutron detector solutions that can capture high-quality neutron images. Monte Carlo simulations were extensively employed for these optimization efforts. The system has been shown to produce high quality neutron radiographs in terms of contrast, noise, and resolution, using many different techniques for imaging. Many materials were explored for moderation and shielding, and many neutron detectors were researched and experimented with to demonstrate advantages and disadvantages for their use on the Phoenix neutron imaging system. Sample images will be shown and discussed including conventional radiography using medical, industrial, and photographic film, 2-dimension digital imaging using pixelated cameras such as Charge Coupled Devices (CCD), Complementary Metal Oxide Semiconductors (CMOS), amorphous Silicon (aSi), and Computed Radiography (CR). Neutron Computed Tomography (nCT) is demonstrated as a 3-dimensional imaging technique as well. Case studies will be discussed and options for further optimization for collimator, moderator, and detector designs will be outlined. Recommendations for future research will be discussed in the final chapter.

Download or read book Development of a Compact Neutron Generator to be Used For Associated Particle Imaging Utilizing a RF Driven Ion Source written by Ying Wu and published by . This book was released on 2009 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ion source development plays an important role for improving and advancing the neutron generator technology used for active interrogation techniques employed by the Department of Homeland Security. Active neutron interrogation using compact neutron generators has been around since the late 1950's for use in oil well logging. However, since the September 11th, 2001 terrorists attack, much attention has been paid to the field of active neutron interrogation for detecting hidden explosives and special nuclear materials (SNM) in cargo and luggage containers through the development of effective and efficient radioactive sources and detectors. In particular, the Associated Particle Imaging (API) method for detecting and imaging explosives is of great interest New compact neutron generators will help to enhance the capabilities of existing threat detection systems and promote the development of cutting-edge detection technologies. The work performed in this thesis includes the testing of various ion source configurations and the development and characterization of an inductively coupled radio frequency (RF) ion source for use in compact neutron generators. These ion source designs have been investigated for the purpose of D-T neutron generation for explosive detection via the Associated Particle Imaging (API) technique. API makes use of the 3.5 MeV alpha particles that are produced simultaneously with the 14 MeV neutrons in the deuterium-tritium (2D(3T, n)4) fusion reaction to determine the direction of the neutrons and to reduce background noise. The Associated Particle Imaging neutron generator required a beam spot of 1-mm or less in diameter at the target in order to achieve the necessary spatial image resolution. For portable neutron generators used in API, the ion source and target cannot be water-cooled and the power deposited on the target must be low. By increasing the atomic ion fraction, the ion beam can be used more efficiently to generate neutrons, resulting in a lower beam power requirement and an increased lifetime of the alpha detector inside the acceleration column. Various source configurations, antenna design, and permanent magnet placement have been investigated so as to develop an ion source which could provide high monatomic deuterium species and high current density at relatively low RF powers (less than 200 W). In this work, an RF ion source was developed that uses an external, planar, spiral antenna at 13.56 MHz with a quartz source body and side multi-cusp magnets to generate hydrogen isotope plasmas with high mono-atomic ion species (> 80%) while consuming only 150 watts of power and operating under 10 mTorr of gas pressure. A single acceleration gap with a secondary electron suppression electrode are used in the tube. Experimental measurements of the ion source plasma parameters including ion current density, atomic ion fraction, ignition and operating pressures, electron temperature, and electron density are presented along with a discussion on the ion optics and engineering challenges. It is shown that the measured neutron yield for the developed D-D neutron generator was 2 x 105 n/s, which scales to 8 x 107 n/s for D-T operation. In addition, initial measurements of the neutron generator performance including the beam spot size, associated particle detection, and neutron tube (without pumping) operation will be discussed. Some suggestions for future improvement are also presented in this dissertation.

Download or read book Design Development Characterization and Application of a New Neutron Imaging Facility at the Penn State Breazeale Reactor written by Alibek Kenges and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron imaging is a powerful tool in the field of non-destructive testing that utilizes unique attenuation properties of neutrons allowing through-images of some high-density objects. The Radiation Science and Engineering Center (RSEC) has had a neutron imaging facility for the last several decades. With the installation of a new core moderator assembly and new beam ports at the RSEC -- the Penn State Breazeale Reactor (PSBR) in 2018, a dedicated neutron beam port became available for a new neutron imaging facility at RSEC (RSEC -- NIF). The initial design of the beam port designated for the RSEC -- NIF was of divergent type that needed to be upgraded by means of collimator components and filters. After a thorough investigation of existing neutron imaging facilities around the world, it has been decided to collimate the beam port with convergent and divergent collimators and to filter the gamma and neutron content with the single crystal bismuth and sapphire filters. A set of system characterization experiments were conducted at the RSEC -- NIF that confirmed the system's correspondence to a Category I facility by ASTM standards. In addition to that, the collimation ratio of the new system was measured following the procedures given in the ASTM protocols and resulted in the effective L/D ratio value between 107 and 115. The thermal flux across the exit surface from the beam port at the biological shield was measured to be equal to 5.4E+06 n/cm^2-s at 1MWth reactor power. The application of the RSEC -- NIF's capabilities in neutron radiography (NR) and tomography (NT) techniques were demonstrated imaging different types of environmental samples for the presence and visualization of microplastic particles. Preliminary results of NT experiments conducted at the RSEC -- NIF have shown that this technique can be used as an intermediary step to visualize the content and spatial distribution of microplastics in the sand columns. Additionally, the NR capabilities of the RSEC -- NIF were utilized to visualize the microplastic particles in the sediment samples and used water filters. All obtained results and the continuation of research in this direction can potentially shed some light in the general research of microplastic transport mechanisms in different terrestrial and aquatic ecosystems.

Download or read book Neutron Generators for Analytical Purposes written by and published by . This book was released on 2012 with total page 162 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 Characteristics of a RF Driven Ion Source for a Neutron Generator Used For Associated Particle Imaging written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present recent work on a prototype compact neutron generator for associated particle imaging (API). API uses alpha particles that are produced simultaneously with neutrons in the deuterium-tritium (2D(3T, n)4 alpha) fusion reaction to determine the direction of the neutrons upon exiting the reaction. This method determines the spatial position of each neutron interaction and requires the neutrons to be generated from a small spot in order to achieve high spatial resolution. The ion source for API is designed to produce a focused ion beam with a beam spot diameter of 1-mm or less on the target. We use an axial type neutron generator with a predicted neutron yield of 108 n/s for a 50 muA D/T ion beam current accelerated to 80 kV. The generator utilizes a RF planar spiral antenna at 13.56 MHz to create a highly efficient inductively-coupled plasma at the ion source. Experimental results show that beams with an atomic ion fraction of over 80percent can be obtained while utilizing only 100 watts of RF power in the ion source. A single acceleration gap with a secondary electron suppression electrode is used in the tube. Experimental results, such as the current density, atomic ion fraction, electron temperature, and electron density, from ion source testing will be discussed.

Download or read book Recent Advancements in X Ray and Neutron Imaging of Dynamic Processes in Earth Sciences written by Lucia Mancini and published by Frontiers Media SA. This book was released on 2020-12-01 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

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 Characterization of Deuteron Deuteron Neutron Generators written by Cory Scott Waltz and published by . This book was released on 2016 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: A facility based on a next-generation, high-flux D-D neutron generator (HFNG) was commissioned at the University of California Berkeley. The characterization of the HFNG is presented in the following study. The current generator design produces near mono-energetic 2.45 MeV neutrons at outputs of 10^8 n/s. Calculations provided show that future conditioning at higher currents and voltages will allow for a production rate over 10^10 n/s. Characteristics that affect the operational stability include the suppression of the target-emitted back streaming electrons, target sputtering and cooling, and ion beam optics. Suppression of secondary electrons resulting from the deuterium beam striking the target was achieved via the implementation of an electrostatic shroud with a voltage offset of greater than -400 V relative to the target. Ion beam optics analysis resulted in the creation of a defocussing extraction nozzle, allowing for cooler target temperatures and a more compact design. To calculate the target temperatures, a finite difference method (FDM) solver incorporating the additional heat removal effects of subcooled boiling was developed. Validation of the energy balance results from the finite difference method calculations showed the iterative solver converged to heat removal results within about 3% of the expected value. Testing of the extraction nozzle at 1.43 mA and 100 kV determined that overheating of the target did not occur as the measured neutron flux of the generator was near predicted values. Many factors, including the target stopping power, deuterium atomic species, and target loading ratio, affect the flux distribution of the HFNG neutron generator. A detailed analysis to understand these factors effects is presented. Comparison of the calculated flux of the neutron generator using deuteron depth implantation data, neutron flux distribution data, and deuterium atomic species data matched the experimentally calculated flux determined from indium foil irradiations. An overview of experiments using the HFNG, including medical isotope cross section measurements, geochronology, delayed gamma measurements from uranium fission, and single event upset of cpu's is discussed. Future work should focus on the reduction of beam induced arcing between the shroud and the vacuum chamber. Investigation of insulator charge build-up, as well as electrical flash-over of insulators should be explored. The reduction of beam induced arcing will allow for larger beam currents and acceleration voltages, therefore increasing the neutron flux.

Download or read book Development of a Neutron Diffraction System and Neutron Imaging System for Beamport Characterization written by Troy Casey Unruh and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor neutron detector design, fabrication and testing are all performed at Kansas State University (KSU). The most prevalent neutron detectors built by the KSU Semiconductor Materials And Radiological Technologies Laboratory (SMART Lab) are comprised of silicon diodes with [superscript]6LiF as a neutron converter material. Neutron response testing and calibration of the detectors is performed in a neutron detector test facility. The facility utilizes diffraction with a pyrolytic graphite (PG) monochromator to produce a diffracted neutron beam at the northwest beamport of the KSU Training Research Isotope production General Atomics (TRIGA) Mark-II nuclear reactor. A 2-D neutron beam monitor can also be used in conjunction with the test facility for active calibrations. Described in the following work are the design, construction and operation of a neutron detector test facility and a 2-D neutron detection array. The diffracted neutron beam at the detector test facility has been characterized to yield a neutron beam with an average Gaussian energy of 0.0253 eV. The diffracted beam yields a flux of 1.2x10[superscript]4 neutrons/cm[superscript]2/s at 100 kW of reactor power. The PG monochromator is diffracting on the (002) plane that has been positioned at a Bragg angle of 15.5 degrees. The 2-D neutron detection array has been characterized for uniform pixel response and uniform neutron detection efficiency. The 2-D 5x5 array of neutron detectors with a neutron detection efficiency of approximately 0.5 percent has been used as a beam monitor when performing detector testing. The amplifier circuits for the 5x5 array were designed at the KSU Electronics Design Lab (EDL) and were coupled to a LabVIEW field-programmable gate array that is read out by a custom LabVIEW virtual instrument. The virtual instrument has been calibrated to produce a pixel response that varies by less than two percent from pixel to pixel. The array has been used for imaging and active monitoring of the diffracted neutron beam at the detector test facility. The following work is part of on-going research to develop various types of solid state semiconductor neutron detectors.

Download or read book Al Adab Fi Al Kuwayt Khilal Nisf Qarn 1950 200 written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Utilization of Small Accelerator Neutron Generators for Neutron Radiography written by G. BREYNAT and published by . This book was released on 1969 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Compact Neutron Generator Using a Field Ionization Source written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Field ionization as a means to create ions for compact and rugged neutron sources is pursued. Arrays of carbon nano- bers promise the high eld-enhancement factors required for efficient field ionization. We report on the fabrication of arrays of field emitters with a density up to 106 tips/cm2 and measure their performance characteristics using electron field emission. The critical issue of uniformity is discussed, as are efforts towards coating the nano-fibers to enhance their lifetime and surface properties.

Download or read book Neutron Radiography System Design and Characterization written by Hisao Kobayashi and published by . This book was released on 1996 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Neutron Radiography System Design and Characterization Proceedings written by Hisao Kobayashi and published by . This book was released on 1996 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Method for Intercalibrating of Neutron Sources with Different Spectra written by A. Wattenberg and published by . This book was released on 1950 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Active Interrogation Using Electronic Neutron Generators for Nuclear Safeguards Applications written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Active interrogation, a measurement technique which uses a radiation source to probe materials and generate unique signatures useful for characterizing those materials, is a powerful tool for assaying special nuclear material. The most commonly used technique for performing active interrogation is to use an electronic neutron generator as the probe radiation source. Exploiting the unique operating characteristics of these devices, including their monoenergetic neutron emissions and their ability to operate in pulsed modes, presents a number of options for performing prompt and delayed signature analyses using both photon and neutron sensors. A review of literature in this area shows multiple applications of the active neutron interrogation technique for performing nuclear nonproliferation measurements. Some examples include measuring the plutonium content of spent fuel, assaying plutonium residue in spent fuel hull claddings, assaying plutonium in aqueous fuel reprocessing process streams, and assaying nuclear fuel reprocessing facility waste streams to detect and quantify fissile material. This paper discusses the historical use of this technique and examines its context within the scope and challenges of next-generation nuclear fuel cycles and advanced concept nuclear fuel cycle facilities.

Download or read book Three New Nondestructive Evaluation Tools Based on High Flux Neutron Sources written by and published by . This book was released on 1997 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nondestructive evaluation methods and systems based on specific attributes of neutron interactions with materials are being developed. The special attributes of neutrons are low attenuation in most engineering materials, strong interaction with low Z elements, and epithermal neutron absorption resonances. The three methods under development at ORNL include neutron based tomography and radiography; through thickness, nondestructive texture mapping; and internal, noninvasive temperature measurement. All three techniques require high flux sources such as the High Flux Isotope Reactor, a steady state source, or the Oak Ridge Electron Linear Accelerator, a pulsed neutron source. Neutrons are quite penetrating in most engineering materials and thus can be useful to detect internal flaws and features. Hydrogen atoms, such as in a hydrocarbon fuel, lubricant, or a metal hydride, are relatively opaque to neutron transmission and thus neutron based tomography/radiography is ideal to image their presence. Texture, the nonrandom orientation of crystalline grains within materials, can be mapped nondestructively using neutron diffraction methods. Epithermal neutron resonance absorption is being studied as a noncontacting temperature sensor. This paper highlights the underlying physics of the methods, progress in development, and the potential benefits for science and industry of the three facilities.