Download or read book Development of High Efficiency Neutron Detectors written by and published by . This book was released on 1993 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have designed a novel neutron detector system using conventional 3He detector tubes and composites of polyethylene, and graphite. At this time the design consists entirely of MCNP simulations of different detector configurations and materials. These detectors are applicable to low-level passive and active neutron assay systems such as the passive add-a-source and the 252Cf shuffler. Monte Carlo simulations of these neutron detector designs achieved efficiencies of over 35% for assay chambers that can accommodate 55-gal. drums. Only slight increases in the number of detector tubes and helium pressure are required. The detectors also have reduced die-away times. Potential applications are coincident and multiplicity neutron counting for waste disposal and safeguards. We will present the general design philosophy, underlying physics, calculation mechanics, and results.

Download or read book The Theory and Practice of Scintillation Counting written by J. B. Birks and published by Elsevier. This book was released on 2013-10-22 with total page 685 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Theory and Practice of Scintillation Counting is a comprehensive account of the theory and practice of scintillation counting. This text covers the study of the scintillation process, which is concerned with the interactions of radiation and matter; the design of the scintillation counter; and the wide range of applications of scintillation counters in pure and applied science. The book is easy to read despite the complex nature of the subject it attempts to discuss. It is organized such that the first five chapters illustrate the fundamental concepts of scintillation counting. Chapters 6 to 10 detail the properties and applications of organic scintillators, while the next four chapters discuss inorganic scintillators. The last two chapters provide a review of some outstanding problems and a postscript. Nuclear physicists, radiation technologists, and postgraduate students of nuclear physics will find the book a good reference material.

Download or read book Development of A Self Biased High Efficiency Solid State Neutron Detector for MPACT Applications written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron detection is an important aspect of materials protection, accounting, and control for transmutation (MPACT). Currently He-3 filled thermal neutron detectors are utilized in many applications; these detectors require high-voltage bias for operation, which complicates the system when multiple detectors are used. In addition, due to recent increase in homeland security activity and the nuclear renaissance, there is a shortage of He-3, and these detectors become more expensive. Instead, cheap solid-state detectors that can be mass produced like any other computer chips will be developed. The new detector does not require a bias for operation, has low gamma sensitivity, and a fast response. The detection system is based on a honeycomb-like silicon device, which is filled with B-10 as the neutron converter; while a silicon p-n diode (i.e., solar cell type device) formed on the thin silicon wall of the honeycomb structure detects the energetic charged particles emitted from the B-10 conversion layer. Such a detector has ~40% calculated thermal neutron detection efficiency with an overall detector thickness of about 200?m. Stacking of these devices allows over 90% thermal neutron detection efficiency. The goal of the proposed research is to develop a high-efficiency, low-noise, self-powered solid-state neutron detector system based on the promising results of the existing research program. A prototype of this solid-state neutron detector system with sufficient detector size (up to 8-inch diam., but still portable and inexpensive) and integrated with interface electronics (e.g., preamplifier) will be designed, fabricated, and tested as a coincidence counter for MPACT applications. All fabrications proposed are based on silicon-compatible processing; thus, an extremely cheap detector system could be massively produced like any other silicon chips. Such detectors will revolutionize current neutron detection systems by providing a solid-state alternative to traditional gas-based neutron detectors.

Download or read book Development of a High efficiency Neutron Counter Using Novel Materials written by and published by . This book was released on 1997 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron detection efficiency is an important figure of merit for waste assay applications that must measure small quantities of material. It is also important for neutron coincidence counting and multiplicity counting because the detection of double- and triple-correlated events scales as the detection efficiency squared and cubed, respectively. Conventional thermal neutron detection systems typically employ 3He detector tubes embedded in polyethylene. The polyethylene moderates the neutrons so they can be detected by the 3He tubes. However, the hydrogen in the moderator also absorbs neutrons and reduces the diffusion length. We have extensively explored alternate designs that use both polyethylene and other industrial plastics with lower concentrations of hydrogen. In MCNP studies, we have achieved higher detection efficiency by using both polyethylene and other plastics in a hybrid design. In this paper we will present the design of a nominal 30%-efficient, 200-liter neutron counter that uses a hybrid design. We will show comparison results of this design compared to a standard polyethylene design. Finally, this counter has been constructed and tested, and was used in the Los Alamos waste assay course. We will show comparisons of the experimental results from this counter to the MCNP predictions.

Download or read book Radiation Detection for Nuclear Physics written by David Gareth Jenkins and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Radiation detection is key to experimental nuclear physics as well as underpinning a wide range of applications in nuclear decommissioning, homeland security and medical imaging. This book presents the state-of-the-art in radiation detection of light and heavy ions, beta particles, gamma rays and neutrons. The underpinning physics of different detector technologies is presented, and their performance is compared and contrasted. Detector technology likely to be encountered in contemporary international laboratories is also emphasized. There is a strong focus on experimental design and mapping detector technology to the needs of a particular measurement problem. This book will be invaluable to PhD students in experimental nuclear physics and nuclear technology, as well as undergraduate students encountering projects based on radiation detection for the first time. Part of IOP Series in Nuclear Spectroscopy and Nuclear Structure." -- Prové de l'editor.

Download or read book Development of a High count rate Neutron Detector with Position Sensitivity and High Efficiency written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: While the neutron scattering community is bombarded with hints of new technologies that may deliver detectors with high-count-rate capability, high efficiency, gamma-ray insensitivity, and high resolution across large areas, only the time-tested, gas-filled [sup 3]He and scintillation detectors are in widespread use. Future spallation sources with higher fluxes simply must exploit some of the advanced detector schemes that are as yet unproved as production systems. Technologies indicating promise as neutron detectors include pixel arrays of amorphous silicon, silicon microstrips, microstrips with gas, and new scintillation materials. This project sought to study the competing neutron detector technologies and determine which or what combination will lead to a production detector system well suited for use at a high-intensity neutron scattering source.

Download or read book High Dose Neutron Detector Development Using 10B Coated Cells written by and published by . This book was released on 2016 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: During FY16 the boron-lined parallel-plate technology was optimized to fully benefit from its fast timing characteristics in order to enhance its high count rate capability. To facilitate high count rate capability, a novel fast amplifier with timing and operating properties matched to the detector characteristics was developed and implemented in the 8" boron plate detector that was purchased from PDT. Each of the 6 sealed-cells was connected to a fast amplifier with corresponding List mode readout from each amplifier. The FY16 work focused on improvements in the boron-10 coating materials and procedures at PDT to significantly improve the neutron detection efficiency. An improvement in the efficiency of a factor of 1.5 was achieved without increasing the metal backing area for the boron coating. This improvement has allowed us to operate the detector in gamma-ray backgrounds that are four orders of magnitude higher than was previously possible while maintaining a relatively high counting efficiency for neutrons. This improvement in the gamma-ray rejection is a key factor in the development of the high dose neutron detector.

Download or read book Development of a Solid State Neutron Detector for SNAP 10A written by A. Chesavage and published by . This book was released on 1966 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dual side Etched Microstructured Semiconductor Neutron Detectors written by Ryan G. Fronk and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest in high-efficiency replacements for thin-film-coated thermal neutron detectors led to the development of single-sided microstructured semiconductor neutron detectors (MSNDs). MSNDs are designed with micro-sized trench structures that are etched into a vertically-oriented pvn-junction diode, and backfilled with a neutron converting material, such as 6LiF. Neutrons absorbed by the converting material produce a pair of charged-particle reaction products that can be measured by the diode substrate. MSNDs have higher neutron-absorption and reaction-product counting efficiencies than their thin-film-coated counterparts, resulting in up to a 10x increase in intrinsic thermal neutron detection efficiency. The detection efficiency for a single-sided MSND is reduced by neutron streaming paths between the conversion-material filled regions that consequently allow neutrons to pass undetected through the detector. Previously, the highest reported intrinsic thermal neutron detection efficiency for a single MSND was approximately 30%. Methods for double-stacking and aligning MSNDs to reduce neutron streaming produced devices with an intrinsic thermal neutron detection efficiency of 42%. Presented here is a new type of MSND that features a complementary second set of trenches that are etched into the back-side of the detector substrate. These dual-sided microstructured semiconductor neutron detectors (DS-MSNDs) have the ability to absorb and detect neutrons that stream through the front-side, effectively doubling the detection efficiency of a single-sided device. DS-MSND sensors are theoretically capable of achieving greater than 80% intrinsic thermal neutron detection efficiency for a 1-mm thick device. Prototype DS-MSNDs with diffused pvp-junction operated at 0-V applied bias have achieved 53.54±0.61%, exceeding that of the single-sided MSNDs and double-stacked MSNDs to represent a new record for detection efficiency for such solid-state devices.

Download or read book Neutron Detectors for Scattering Applications written by Yacouba Diawara and published by Springer Nature. This book was released on 2023-08-04 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the most common neutron detectors used in neutron scattering facilities and all of those in use at Oak Ridge National Lab. It starts describing the facilities, instruments and the critical detector parameters needed by various instruments. Then the key components of the 3He-based linear position-sensitive detectors as well as on their electronics, which require particular attention to signal processing and noise reduction, are introduced. One chapter is dedicated to the 3He alternatives where scintillators play a critical role. It also covers emerging neutron detection technologies including semiconductors, vacuum-based devices and their associated readouts, which will be required in the future for high rate and high-resolution neutron detectors. The authors explain the logic behind the choice of materials as well as the various constraints that neutron detectors must respect to be useful. Some of these constraints, such as efficiency and gamma-ray sensitivity are common to all neutron counters while others, like timing resolution, dynamic range, and peak counting rate, depend on the applications. The book guides experts, the nuclear science community, and young scholars through the physical processes and the required electronics in a way that is accessible for those not professionally involved in designing detector’s components and electronic circuits.

Download or read book High Precision Thermal Neutron Detectors written by and published by . This book was released on 1994 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-dimensional position sensitive detectors are indispensable in neutron diffraction experiments for determination of molecular and crystal structures in biology, solid-state physics and polymer chemistry. Some performance characteristics of these detectors are elementary and obvious, such as the position resolution, number of resolution elements, neutron detection efficiency, counting rate and sensitivity to gamma-ray background. High performance detectors are distinguished by more subtle characteristics such as the stability of the response (efficiency) versus position, stability of the recorded neutron positions, dynamic range, blooming or halo effects. While relatively few of them are needed around the world, these high performance devices are sophisticated and fairly complex; their development requires very specialized efforts. In this context, we describe here a program of detector development, based on 3He filled proportional chambers, which has been underway for some years at Brookhaven. Fundamental approaches and practical considerations are outlined that have resulted in a series of high performance detectors with the best known position resolution, position stability, uniformity of reliability over time of this type.

Download or read book Advanced Dual sided Microstructured Semiconductor Neutron Detectors and Instrumentation written by Taylor R. Ochs and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dual-Sided Microstructured Semiconductor Neutron Detectors (DS-MSNDs) have been developed as a viable alternative to expensive 3He for thermal-neutron detection. DS-MSNDs were designed as an advancement on single-sided MSNDs which comprise high-aspect ratio trenches backfilled with 6LiF neutron conversion material etched deep into silicon pvn-junction diodes. Neutrons react in the conversion material, which produces energetic charged-particle reaction products that are measured in the adjacent silicon microfeatures. Single-sided MSNDs have been produced with an intrinsic thermal-neutron detection efficiency of 30-35% for normally incident neutrons, and the key limiting factor in detection efficiency is neutron free streaming paths through the neutron insensitive silicon fins. The DS-MSND incorporates a second set of 6LiF-backfilled trenches etched on the back-side of a thicker silicon diode that are offset from the front-side trenches to eliminate the neutron free streaming paths. Monte Carlo simulations show DS-MSNDs only 1.5-mm thick are theoretically capable of 80% intrinsic thermal-neutron detection efficiency, which could directly match commonly available 3He detectors. This work describes the design of DS-MSNDs including electric field modeling and microfeature geometry optimization with MCNP simulations, and fabrication process improvements implemented that elevate the state-of-the-art. The previous world record for intrinsic thermal-neutron detection efficiency for semiconductor neutron detectors was 53.5 ± 0.6%. Advancements in deep-trench etching and 6LiF backfilling methods presented herein have increased the current record intrinsic-thermal neutron detection efficiency to 69.3 ± 1.5%. Several prototype detector systems were fabricated implementing DS-MSND and MSND technology to aid in search and localization of special nuclear material. Drop-in replacements for small-diameter, high-pressure 3He detectors, and the DS-MSND-based HeRep Mk IV measured 80% to 115% of the count rate of a similarly sized 10-atm 3He detector based on the detector and source moderation configuration. Additionally, modular neutron detectors were developed for use in a high-sensitivity, low profile, wearable neutron detector for covert or overt source detection missions by warfighters, first responders, or law enforcement personnel. Additionally, MCNP simulations show the wearable detectors have potential to as operate as high-accuracy, real-time, neutron dose meters. The DS-MSND-based detector systems with on-board electronics offer a low-cost, low-power, compact, high sensitivity, alternative to 3He neutron detection.

Download or read book Roadmap for High Efficiency Solid State Neutron Detectors written by T. Wang and published by . This book was released on 2005 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid-state thermal neutron detectors are generally fabricated in a planar configuration by coating a layer of neutron-to-alpha converter material onto a semiconductor. The as-created alpha particles in the material are expected to impinge the semiconductor and create electron-hole pairs which provide the electrical signal. These devices are limited in efficiency to a range near (2-5%)/cm{sup 2} due to the conflicting thickness requirements of the converter layer. In this case, the layer is required to be thick enough to capture the incoming neutron flux while at the same time adequately thin to allow the alpha particles to reach the semiconductor. A three dimensional matrix structure has great potential to satisfy these two requirements in one device. Such structures can be realized by using PIN diode pillar elements to extend in the third dimension with the converter material filling the rest of the matrix. Our strategy to fabricate this structure is based on both ''top-down'' and ''bottom-up'' approaches. The ''top down'' approach employs high-density plasma etching techniques, while the ''bottom up'' approach draws on the growth of nanowires by chemical vapor deposition. From our simulations for structures with pillar diameters from 2 {micro}m down to 100 nm, the detector efficiency is expected to increase with a decrease in pillar size. Moreover, in the optimized configuration, the detector efficiency could be higher than 75%/cm{sup 2}. Finally, the road map for the relationship between detector diameter and efficiency will be outlined.

Download or read book The Development of 3He Neutron Detectors for Applications in High Level Gamma ray Backgrounds written by Howard O. Menlove and published by . This book was released on 1995 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Nuclear Radiation Detectors written by S. S. Kapoor and published by New Age International. This book was released on 1986-04 with total page 252 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.