Download or read book Advanced Microstructured Semiconductor Neutron Detectors written by Steven Lawrence Bellinger and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The microstructured semiconductor neutron detector (MSND) was investigated and previous designs were improved and optimized. In the present work, fabrication techniques have been refined and improved to produce three-dimensional microstructured semiconductor neutron detectors with reduced leakage current, reduced capacitance, highly anisotropic deep etched trenches, and increased signal-to-noise ratios. As a result of these improvements, new MSND detection systems function with better gamma-ray discrimination and are easier to fabricate than previous designs. In addition to the microstructured diode fabrication improvement, a superior batch processing backfill-method for 6LiF neutron reactive material, resulting in a nearly-solid backfill, was developed. This method incorporates a LiF nano-sizing process and a centrifugal batch process for backfilling the nanoparticle LiF material. To better transition the MSND detector to commercialization, the fabrication process was studied and enhanced to better facilitate low cost and batch process MSND production. The research and development of the MSND technology described in this work includes fabrication of variant microstructured diode designs, which have been simulated through MSND physics models to predict performance and neutron detection efficiency, and testing the operational performance of these designs in regards to neutron detection efficiency, gamma-ray rejection, and silicon fabrication methodology. The highest thermal-neutron detection efficiency reported to date for a solid-state semiconductor detector is presented in this work. MSNDs show excellent neutron to gamma-ray (n/[gamma]) rejection ratios, which are on the order of 106, without significant loss in thermal-neutron detection efficiency. Individually, the MSND is intrinsically highly sensitive to thermal neutrons, but not extrinsically sensitive because of their small size. To improve upon this, individual MSNDs were tiled together into a 6x6-element array on a single silicon chip. Individual elements of the array were tested for thermal-neutron detection efficiency and for the n/[gamma] reject ratio. Overall, because of the inadequacies and costs of other neutron detection systems, the MSND is the premier technology for many neutron detection applications.

Download or read book An Advanced Microstructured Semiconductor Radiation Detector for Neutron Imaging and Oil Well Logging written by Sanchit Sharma and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this dissertation will serve as an essential tool for modern nuclear engineers to perform radiation transport with import of complex computer aided design (CAD) models efficiently. Performing radiation transport with complex CAD geometries and obtaining accurate detector response functions has been a major challenge. For micro-structured semiconductor detectors, results obtained from radiation transport alone are not enough to provide a clear picture of expected performance. Hence, the work presented in this dissertation is divided into two major research areas (RAs). RA 1 describes methods for sensor response modelling with hybrid Geant4 geometries consisting of both conventional C++ based models and complex CAD based models in a single simulation. This RA will address the methods developed for radiation transport models and benchmarking experimental detector responses. Additionally, this RA will further discuss how these models were later utilized for finalizing design parameters of a semiconductor radiation detection system (Timepix3 coupled with Dual-Sided Microstructured Semiconductor Neutron Detector). Multiple bugs were identified in Geant4 source code as a result of the work presented in RA 1. RA 2 of this dissertation will provide detailed analysis of the existing boundary conditions of the DS-MSND and MSND detectors. Finite Element Analysis based semiconductor physics modeling was performed to investigate various parameters of the Si-SiO2 interface. The radiation transport models were developed for simulating the Kansas State University Materials Interrogation (KSUMI) test facility that was set up to enable bulk-material irradiation experiments that replicate similar oil-well logging scenarios. These experiments were conducted with an aim to address the problem of replacement of conventional radioisotope sources commonly used in oil-well logging industries. An exploration tool similar to an oil-well logging tool was used to conduct experiments with water and sand as testing materials. The facility includes a 2500-gallon concrete test chamber to be filled with testing material with an aluminum pipe going horizontally through it, permitting placement of a neutron source and radiation sensors. A machine-based 14.1 MeV deuterium-tritium neutron source was used to irradiate the 2500-gallon testing material. Experiments were performed with tap water and sand as bulk testing materials. Irradiation was performed for one hour and results were obtained from a BF3/3He neutron sensor, a BF3 neutron sensor, and two NaI gamma sensors placed at different locations within the exploration tool. Geant4, a Monte-Carlo based toolkit, was deployed on a high-performance computing system to simulate the entire experiment in order to benchmark the experimental responses obtained from the photon and neutron sensors. The facility was modeled in detail with accurate dimensions and material compositions. Materials such as tap water, high-density polyethylene, and aluminum metal were modeled with thermal neutron scattering cross-sections. The reference physics list QGSP_BIC_HP along with G4NDL and S([alpha],[beta]) cross-sections were found to be appropriate for simulation of neutron interrogation experiments with neutron energies lower than 20 MeV. The experimental results obtained were successful in characterizing the bulk testing materials, and results obtained from Geant4 were found to be in good agreement with the experimental results in most cases. The source code developed for the above method was then utilized to design the physical parameters for an X-DS-MSND system. These detectors have the benefit of doubling neutron detection efficiency as compared to single-sided devices (X-MSND) by staggering 6LiF-filled trenches between the top and bottom surface of a silicon diode. This produces a more complex electric field distribution and depletion characteristics in the diode and creates an indirect path for signal carrier transport between device electrodes. Geant4 was extensively utilized for radiation transport and interaction modeling, and Allpix Squared was used for mobile charge carrier transport and total charge collection. The results of this simulation work provided an estimate of charge cluster shape and intensity for a pixel array configuration corresponding to Timepix3 read-out system. In addition, imaging performance for transmission radiography was demonstrated with a simple two-dimensional shape in a Gaussian beam of thermal neutrons. The simulated neutron detection efficiency was 57.6%. It was discovered that the Allpix Squared is not optimal for simulation of complex boundary conditions and charge carrier transport inside the DS-MSND. To understand the behavior of charge carriers in the presence of a complex electric field and boundary conditions, a simpler non-conformally doped MSND geometry was fabricated and analyzed. This sensor geometry produced a complex electric field distribution and depletion characteristics within the diode. The fixed oxide charge present at the trench walls and its effects on the depletion characteristics and electric field were analyzed. The capacitance-voltage and current-voltage curve characterizations were performed for these prototypes and compared with the COMSOL Multiphysics simulations. An 241Am alpha particle source was further utilized to perform spectral analysis. Geant4 was utilized for radiation transport, interaction modeling, and benchmarking the spectral data. The results of this simulation work provided a reasonable confidence in capability to obtain and benchmark electric fields and spectral data for complex micro-structured semiconductor radiation detectors. Further, COMSOL Multiphysics was used to account for time-dependent charge carrier motion and detector response for these boundary conditions. As a result of work presented in RA 1 and RA 2, important features in the MSND/DS-MSND geometry were discovered that could significantly impact the device's performance. These features were incorporated in the updated Monte-Carlo model of the DS-MSND sensor. Simulated response of the updated DS-MSND sensor as a replacement of BF3/3He was then analyzed for the oil-well logging irradiation environment using Geant4 simulations. The results obtained from these simulations establish DS-MSND as a strong contender for replacing BF3/3He sensors for oil well logging experiments.

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 Simulation and Validation of Charge Carrier Drift in Pixelated Microstructured Semiconductor Neutron Detectors written by Diego Laramore and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A semiconductor neutron imaging device is proposed (X-MSND) based on high efficiency, Micro-structured Semiconductor Neutron Detector (MSNDs) bump bonded onto a Timepix pixelated readout chip. The device serves as a combined neutron and photon imager with a 256x256 pixel array, using per-pixel time-over-threshold (ToT) energy deposition. The X-MSND design has produced thermal neutron detection efficiency of 14%, significantly greater than the theoretical maximum of less than 5% for planar devices. Simulated pixel clusters showed similar qualitative characteristics as planar neutron sensitive Timepix hybrid detectors. A workflow for simulating the semiconductor physics, ionization by radiation, and charge carrier transport for micro-structured sensors in general has been devised and described in this work. The simulation workflow began by steady state initial conditions of the X-MSND PIN diode sensor at full bias using COMSOL Multiphysics. This simulation step served the combined purpose of providing the necessary electric field solutions used in charge transport, and provided necessary design and operating parameters for device fabrication. Radiation transport code Geant4 was used to simulate the radiation detection characteristics of the sensor: thermal neutron detection efficiency, energy deposition per detection event, and the location of the ionized charge cloud per interaction are all calculated at this step. Dassault SolidWorks was used to generate Computer-Assisted Drafting (CAD) models of the full micro-structured device geometry, which was then converted and imported into a format that can be interpreted by Geant4 for the radiation transport. Geant4 can then interface directly with a modified version of Allpix^2 to perform charge carrier drift over the entire X-MSND geometry. Fabricated X-MSND devices were tested and evaluated at Kansas State University (KSU), and were found capable of producing high quality radiographs with both X-rays and neutrons. The fabrication of functioning X-MSND/Timepix assemblies was a collaborative effort among several research groups at KSU, domestic and international industrial partners, and international research groups. Fabrication of the X-MSND sensors was performed largely by Radiation Detection Technologies, Inc., with parametric design support from the Radiological System Integration Laboratory (RSIL) and Radiological Engineering Analysis Laboratory (REAL). The processes used in the production of X-MSND sensors are conventional micro-electro-mechanical system (MEMS) photolithography techniques; spin-on deposition and ultraviolet development of photoresist, metal lift-off, and wet etching of silicon are all used over the course of fabrication, and are described in detail. The Electronics Design Laboratory (EDL) of Kansas State University assisted in the design of custom printed circuit boards to which the X-MSND/Timepix assemblies are mounted. External to facilities located at KSU, various industrial manufacturing partners who specialize in Very Large Scale Integration (VLSI) and micro-fabrication assembly processes were also contracted to perform the specialized assembly processes required in assembling the full X-MSND/Timepix systems.

Download or read book Advanced Materials for Radiation Detection written by Krzysztof (Kris) Iniewski and published by Springer Nature. This book was released on 2021-08-05 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers readers an overview of some of the most recent advances in the field of advanced materials used for gamma and X-ray imaging. Coverage includes both technology and applications, with an in-depth review of the research topics from leading specialists in the field. Emphasis is on high-Z materials like CdTe, CZT and GaAs, as well as perovskite crystals, since they offer the best implementation possibilities for direct conversion X-ray detectors. Authors discuss material challenges, detector operation physics and technology and readout integrated circuits required to detect signals processes by high-Z sensors.

Download or read book Scalable Low cost Large area Micro structured Thermal Neutron Detectors written by Siddartha Srinivasan Nandagopala Krishnan and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Pillar Structured Thermal Neutron Detector written by and published by . This book was released on 2008 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work describes an innovative solid state device structure that leverages advanced semiconductor fabrication technology to produce an efficient device for thermal neutron detection which we have coined the 'Pillar Detector'. State-of-the-art thermal neutron detectors have shortcomings in simultaneously achieving high efficiency, low operating voltage while maintaining adequate fieldability performance. By using a three dimensional silicon PIN diode pillar array filled with isotopic 1°boron (1°B), a high efficiency device is theoretically possible. Here we review the design considerations for going from a 2-D to 3-D device and discuss the materials trade-offs. The relationship between the geometrical features and efficiency within our 3-D device is investigated by Monte Carlo radiation transport method coupled with finite element drift-diffusion carrier transport simulations. To benchmark our simulations and validate the predicted efficiency scaling, experimental results of a prototype device are illustrated. The fabricated pillar structures reported in this work are composed of 2 [mu]m diameter silicon pillars with a 2 [mu]m spacing and pillar height of 12 [mu]m. The pillar detector with a 12 [mu]m height achieved a thermal neutron detection efficiency of 7.3% at a reverse bias of -2 V.

Download or read book Study of Transport Behavior and Conversion Efficiency in Pillar Structured Neutron Detectors written by and published by . This book was released on 2007 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Room temperature, high efficiency and scalable radiation detectors can be realized by manipulating materials at the micro scale. With micro-semiconductor-pillars, we will advance the thermal neutron detection efficiency of semiconductor detectors to over 70% with 50 mm in detector thickness. New material science, new transport behavior, neutron to alpha conversion dynamics and their relationship with neutron detection will be discovered with the proposed structures.

Download or read book Application and Development of Microstructured Solid state Neutron Detectors written by Adam D. Weltz and published by . This book was released on 2017 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling and Simulation of Neutron Detectors for the Transient Reactor Test Facility written by Wenkai Fu and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Transient REActor Test (TREAT) facility was restarted and will be used to test accident-tolerant fuels to improve nuclear reactor safety. In this work, alternative neutron detectors for use in core and with the hodoscope at the TREAT facility were modeled and simulated using different computational tools to understand the underlying physics. The Hornyak button scintillation detector used in the original TREAT hodoscope to detect fast neutrons and its variants were evaluated using Geant4 to simulate the coupled nuclear and optical physics. The Hornyak-button model predicted an intrinsic efficiency of 0.35% for mono-directional fission neutrons and strong gamma-induced Cherenkov noise, which agree relatively well with the reported experimental observations. The proposed variants use silicon photomultipliers to reduce Cherenkov noise and have optimized layered or homogenized scintillation volumes. The layered and homogenized variants with 5-cm length were predicted to achieve neutron-detection efficiencies of 3.3% and 1.3%, respectively, at a signal-to-noise ratio of 100. Another candidate devices for the hodoscope are the actinide and hydrogenous microstructured semiconductor neutron detectors (MSNDs) evaluated using Geant4 and MCNP. With a sufficient rejection of the gamma noises, the U235 -filled and the hydrogenous MSNDs were predicted to yield neutron-detection efficiencies of 1.2% and 2.5%, respectively, at the length of 2 cm. The micro-pocket fission detectors (MPFDs) were developed to detect in-core neutrons, and the electron collection process in such devices was evaluated using Garfield++-based computational routine. The high-performance Garfield++ application was developed using the built-in, optimized element-search techniques and a hydrid MPI and OpenMP parallelization scheme. The preliminary results indicated that the averaged deposited energy per fission fragment was 7.15 MeV, and the induced current occured within 400 ns.

Download or read book Soft Computing Theories and Applications written by Millie Pant and published by Springer Nature. This book was released on 2020-02-24 with total page 1452 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book focuses on soft computing and its applications to solve real-world problems in different domains, ranging from medicine and health care, to supply chain management, image processing and cryptanalysis. It includes high-quality papers presented at the International Conference on Soft Computing: Theories and Applications (SoCTA 2018), organized by Dr. B. R. Ambedkar National Institute of Technology, Jalandhar, Punjab, India. Offering significant insights into soft computing for teachers and researchers alike, the book inspires more researchers to work in the field of soft computing.

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 Semiconductor Neutron Detectors written by Ian Suttie and published by . This book was released on 1967* with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Landgoederen en wandelterreinen in Nederland written by and published by . This book was released on 1946 with total page 176 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 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Fabrication and Investigation of Nanomaterials for Industrial Applications written by Sivashankar Krishnamoorthy and published by Springer Nature. This book was released on with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Neutron Detectors written by International Atomic Energy Agency and published by . This book was released on 1966 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: A child speculates about sleeping next to various animals in various places other than one's own, and most desirable, warm bed.