High Energy and Thermal Neutrons Sensitivity of Google Tensor Processing Units

2022 ◽  
pp. 1-1
Author(s):  
Rubens Luiz Rech ◽  
Sujit Malde ◽  
Carlo Cazzaniga ◽  
Maria Kastriotou ◽  
Manon Letiche ◽  
...  
Keyword(s):  
High Energy ◽  
Thermal Neutrons

Soft errors in SRAM devices induced by high energy neutrons, thermal neutrons and alpha particles

2003 ◽  
Author(s):  
H. Kobayashi ◽  
K. Shiraishi ◽  
H. Tsuchiya ◽  
M. Motoyoshi ◽  
H. Usuki ◽  
...  
Keyword(s):  
Soft Errors ◽  
High Energy ◽  
Alpha Particles ◽  
Thermal Neutrons

The Thermal Neutron Decay Time Log

1970 ◽  
Vol 10 (04) ◽  
pp. 365-379 ◽  
Author(s):  
J.S. Wahl ◽  
W.B. Nelligan ◽  
A.H. Frentrop ◽  
C.W. Johnstone ◽  
R.J. Schwartz
Keyword(s):  
Thermal Neutron ◽  
Time Constant ◽  
Decay Time ◽  
High Energy ◽  
Decay Time Constant ◽  
Neutron Decay ◽  
Fast Neutrons ◽  
Neutron Density ◽  
Thermal Neutrons ◽  
Open Hole

Abstract Thermal Neutron Decay Time (TDT) logging tools in 3-3/8 and 1-11/16-in. diameters have been developed for detection and evaluation of water saturation in cased holes. These tools utilize a system of movable and expandable detection time-gates which are automatically adjusted as the log is being run. The two principal detection gates are positioned in time after the neutron burst according to an optimization criterion. An additional gate, delayed until most of the decay has taken place, permits correction for background. This place, permits correction for background. This Scale Factor gating method provides, in each bed, a thermal-decay-time measurement of maximum statistical precision consistent with removal of borehole effects present in the early part of the decay period Increased reliability is afforded by use of digital techniques. Thermal neutron decay time tools employ capture-gamma-ray detection. This choice was based on an extensive series of experiments made to compare gamma-ray detection and direct detection of thermal neutrons. Measurements of thermal neutron decay time constant are affected by local changes in neutron density in the vicinity of the sonde, caused by flow of neutrons by diffusion from one medium to another. The measured decay time constant (T meas) of neutron density at any point may differ, therefore, from the intrinsic decay time constant (T int) produced by absorption alone. The basic physics of neutron diffusion and absorption is reviewed. When the borehole and the formation have different decay time constants and diffusion coefficients, diffusion couples the two regions. Consideration of such effects sheds light on the conditions required for reduction of borehole effects on measured values of the decay time constant. The choice of source-detector spacing is affected. and, for accurate quantitative interpretation, departure curves are required. Departure curves are presented showing the effects of varying cement thickness, casing diameter. and casing fluids Illustrative log examples are shown. Introduction The Thermal Neutron Decay Time (TDT) log provides a determination of the time constant for provides a determination of the time constant for the decay of thermal neutrons in the formation. Hence, it reflects primarily the neutron absorptive properties of the formation. These properties are properties of the formation. These properties are useful in formation evaluation. The most important area of application is in logging cased hole. Because chlorine is by far the strongest thermal neutron absorber of the common earth elements, the TDT log responds largely to the amount of NaCl present in the formation water. As a result, this present in the formation water. As a result, this log resembles the usual open-hole resistivity logs and is easily correlatable with them. When information on lithology and porosity is known or is provided by open-hole logs, a log of neutron provided by open-hole logs, a log of neutron absorption properties permits the solution of a wide variety of problems: saturation determination, oil-water contact location, detection of gas behind casing, etc. Measurements of the thermal neutron decay time constant are made by first irradiating the formation with a pulse of high-energy neutrons from a neutron generator in the sonde, and then, a short time after the neutron source is turned off, determining the rate at which the thermal neutron population decreases. After each neutron burst, the high-energy neutrons are quickly slowed down to thermal velocities by successive collisions with the nuclei of elements in the formation and borehole. The relative number of thermal neutrons remaining in the formation is measured during detection intervals which follow each burst. Between each burst and the beginning of the first detection interval is a delay time which permits the originally fast neutrons to reach thermal permits the originally fast neutrons to reach thermal energy and allows "early" borehole effects to subside. SPEJ p. 365

Fullerite Nano-materials as a Moderator in Neutron Irradiators with Radium Sources: Feasibility and Advantages

2021 ◽  
Vol 14 (2) ◽  
pp. 169-176
Keyword(s):  
Neutron Flux ◽  
Nuclear Reactors ◽  
High Energy ◽  
Thermal Neutrons ◽  
Nano Materials ◽  
Additional Advantage ◽  
Nano Material ◽  
Mcnp5 Code ◽  
Simulation Results ◽  
First Time

Abstract: In this study, the feasibility of using fullerite nano-materials as a moderator in 226Ra-Be neutron irradiators has been theoretically investigated, for the first time. Thermal, intermediate and rapid neutron flux in irradiation channels was calculated using the MCNP5 code when a fullerite nano-material was used as a moderator. The simulation results were then compared with other simulation results performed when paraffin was used as a moderator. The comparison showed that using fullerite instead of paraffin as a moderator results in an increase in the total number of irradiation neutrons by more than twice in average (240 %) for each direction inside the irradiator. This increase is distributed as follows: 27.84 %, 87.84 % and 124.32 % thermal, intermediate and rapid neutrons, respectively. The previous distribution indicates a significant increase in the intermediate and fast neutron flux. This is considered as an additional advantage of using the 226Ra-Be neutron irradiator with a fullerite moderator. The irradiator can then be used not only to irradiate the materials whose irradiation requires thermal neutrons, but also those that require medium- to high-energy neutrons. Keywords: Neutronic irradiator, Ra-Be radiation source, Cadmium, Neutron flux, MCNP5-beta code. PACS: Neutrons diffusion and moderation, 28.20.Gd, Moderators (nuclear reactors), 28.41.Pa.

scholarly journals High-Accuracy Relative Biological Effectiveness Values Following Low-Dose Thermal Neutron Exposures Support Bimodal Quality Factor Response with Neutron Energy

2022 ◽  
Vol 23 (2) ◽  
pp. 878
Author(s):  
Laura C. Paterson ◽  
Amy Festarini ◽  
Marilyne Stuart ◽  
Fawaz Ali ◽  
Christie Costello ◽  
...  
Keyword(s):  
Dna Damage ◽  
Thermal Neutron ◽  
Quality Factor ◽  
Neutron Energy ◽  
Relative Biological Effectiveness ◽  
High Energy ◽  
Weighting Factor ◽  
Radiological Protection ◽  
Thermal Neutrons ◽  
Biological Effectiveness

Theoretical evaluations indicate the radiation weighting factor for thermal neutrons differs from the current International Commission on Radiological Protection (ICRP) recommended value of 2.5, which has radiation protection implications for high-energy radiotherapy, inside spacecraft, on the lunar or Martian surface, and in nuclear reactor workplaces. We examined the relative biological effectiveness (RBE) of DNA damage generated by thermal neutrons compared to gamma radiation. Whole blood was irradiated by 64 meV thermal neutrons from the National Research Universal reactor. DNA damage and erroneous DNA double-strand break repair was evaluated by dicentric chromosome assay (DCA) and cytokinesis-block micronucleus (CBMN) assay with low doses ranging 6–85 mGy. Linear dose responses were observed. Significant DNA aberration clustering was found indicative of high ionizing density radiation. When the dose contribution of both the 14N(n,p)14C and 1H(n,γ)2H capture reactions were considered, the DCA and the CBMN assays generated similar maximum RBE values of 11.3 ± 1.6 and 9.0 ± 1.1, respectively. Consequently, thermal neutron RBE is approximately four times higher than the current ICRP radiation weighting factor value of 2.5. This lends support to bimodal peaks in the quality factor for RBE neutron energy response, underlining the importance of radiological protection against thermal neutron exposures.

scholarly journals Autonomous Neutron Facility for Detecting Fissile Nuclear Materials

2020 ◽  
Keyword(s):  
High Energy ◽  
Fast Neutrons ◽  
Nuclear Materials ◽  
Thermal Neutrons ◽  
Destructive Testing ◽  
Special Equipment ◽  
High Energy Part ◽  
Energy Part ◽  
Neutron Facility ◽  
Non Destructive

The prospect of creating an autonomous neutron facility for the detection of fissile nuclear materials in samples, including those in confined volume, is discussed. It is proposed to obtain a reference field of thermal neutrons on the basis of a polyethylene moderator ball and a portable fast neutrons source, developed at NRC “Accelerator” NSC KIPT based of a continuous electrostatic accelerator of deuterons. The developed source of thermal neutrons is planned to be used to activate small objects and goods in order to identify substances prohibited for movement containing to find 233U, 235U and 239Pu in their composition. The prompt finding of fissile elements will indicate about an attempt to transport them illegally. A more thorough inspection can be carried out using special equipment after the detention of suspicious goods, citizens or vehicles. The possibility of detecting prompt fission neutrons is considered not only in the traditional way using a polyethylene moderator and proportional 3He detector, but also without application of any moderator using oxide or semiconductor scintillators. For detection fissile materials the method based on using the high-energy part of the γ-spectrum of fission fragments (greater than 4900 keV), as well, as the approach applied in the passive non-destructive analysis by the γ-line with Eg = 185.7 keV from 235U, are substantiated. It is shown that the proposed facility for the detection of fissile nuclear materials is able to determine the presence of isotopes 233U, 235U and 239Pu in tested objects and goods with the using non-destructive testing method.

scholarly journals Hybrid halide perovskite neutron detectors

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pavao Andričević ◽  
Gábor Náfrádi ◽  
Márton Kollár ◽  
Bálint Náfrádi ◽  
Steven Lilley ◽  
...  
Keyword(s):  
Homeland Security ◽  
Radiation Transport ◽  
High Energy ◽  
Thermal Neutrons ◽  
Detection Mechanism ◽  
Practical Applications ◽  
Security Issues ◽  
Γ Rays ◽  
Halide Perovskite ◽  
Borated Polyethylene

AbstractInterest in fast and easy detection of high-energy radiation (x-, γ-rays and neutrons) is closely related to numerous practical applications ranging from biomedicine and industry to homeland security issues. In this regard, crystals of hybrid halide perovskite have proven to be excellent detectors of x- and γ-rays, offering exceptionally high sensitivities in parallel to the ease of design and handling. Here, we demonstrate that by assembling a methylammonium lead tri-bromide perovskite single crystal (CH3NH3PbBr3 SC) with a Gadolinium (Gd) foil, one can very efficiently detect a flux of thermal neutrons. The neutrons absorbed by the Gd foil turn into γ-rays, which photo-generate charge carriers in the CH3NH3PbBr3 SC. The induced photo-carriers contribute to the electric current, which can easily be measured, providing information on the radiation intensity of thermal neutrons. The dependence on the beam size, bias voltage and the converting distance is investigated. To ensure stable and efficient charge extraction, the perovskite SCs were equipped with carbon electrodes. Furthermore, other types of conversion layers were also tested, including borated polyethylene sheets as well as Gd grains and Gd2O3 pellets directly engulfed into the SCs. Monte Carlo N-Particle (MCNP) radiation transport code calculations quantitatively confirmed the detection mechanism herein proposed.

Study of changes of thermal neutrons intensity of lithospheric origin for the diagnostics and forecast of earthquakes

2020 ◽  
Author(s):  
Valentina Antonova ◽  
Sergey Kryukov ◽  
Vadim Lutsenko ◽  
Andrey Malimbaev
Keyword(s):  
Neutron Flux ◽  
Thermal Neutron ◽  
Thermal Neutron Flux ◽  
Spectral Composition ◽  
Background Level ◽  
High Energy ◽  
Tien Shan ◽  
Necessary Condition ◽  
High Mountain ◽  
Thermal Neutrons

<p>Studies of variations in the intensity of thermal (epithermal) neutrons at the high-mountain station of cosmic rays near the fracture of the earth's crust (3340 m above sea level, Northern Tien- Shan) showed the promising of using them for the diagnosis and forecast of earthquakes in seismically active regions. A method is proposed for distinguishing features of changes in the intensity of thermal neutrons of lithospheric origin against the background of variations caused by solar and atmospheric disturbance sources. However, a necessary condition for this is the synchronous registration of high-energy neutrons of galactic origin.</p><p>It is known that neutrons in the Earth’s atmosphere arise mainly as a result of the interaction of primary cosmic radiation with the nuclei of air atoms. Statistical analysis of neutron measurements during effective solar events (coronal mass ejections), changes of atmospheric pressure confirmed the genetic relationship of thermal neutrons near the Earth's surface with high-energy neutrons of galactic origin and the similarity of the spectral composition of their variations. The difference is observed only in the range (2·10<sup>-7</sup>÷2·10<sup>-6</sup>)Hz. Variations with the period of 29.5 days (synodic lunar month), due to the gravitational influence of the moon, are present throughout the 12-year period of research of thermal neutrons. The amplitude and its changes were determined by the method of complex demodulation. The periodicity of 29.5 days is absent in the spectrum of high-energy neutrons variations.</p><p> Analysis of experimental data during of seismic activity showed the frequent breakdown of the correlation between the intensity of thermal and high-energy neutrons. The cause of this phenomenon is the additional thermal neutron flux of the lithospheric origin, which appears under these conditions. Simple statistical processing of measured parameters makes it possible to exclude variations of interplanetary and atmospheric origin in the intensity of thermal neutrons and to isolate changes caused by seismic processes.</p><p> We used this method for analysis of thermal neutrons intensity during earthquakes with intensity ≥ 3b in the vicinity of Almaty which took place in 2007-2018. The catalog includes 30 events. The increase of thermal neutrons flux was observed for ~ 60% of events. However, before the earthquake the increase of thermal neutron flux is only observed for ~ 25-30% of events. The amplitude of the additional thermal neutron flux of the lithospheric origin is equal to 5-7% of the background level. Sometimes it reaches values of 10-12%.</p><p>The analysis of our catalog of earthquakes in the vicinity of Almaty also showed that 70% of these events occurred during the full moon or new moon (+/- 2 days).</p>

scholarly journals Investigation of Texture Gradients of Semi-Finished Products by Neutrons and Photons

2011 ◽  
Vol 702-703 ◽  
pp. 499-506 ◽  
Author(s):  
Heinz Guenter Brokmeier ◽  
Christian Randau ◽  
Wei Min Gan ◽  
Michael Hofmann ◽  
Thomas Lippmann ◽  
...  
Keyword(s):  
Materials Science ◽  
Sheet Thickness ◽  
High Energy ◽  
Texture Gradient ◽  
Thermal Neutrons ◽  
Robot System ◽  
Sample Rotation ◽  
Beam Port ◽  
Gauge Volume ◽  
Set Up

Texture gradients are present in most samples, which are due to materials processing. Standard methods to evaluate texture gradients are based on the cut of samples, such as the X-ray investigation of surface textures against the texture inside a sheet. Bulk textures itself averaging over the whole sheet thickness are analysed by thermal neutrons. Both thermal neutrons and photons with high energies allow investigations non-destructively. The beam port Stress-Spec at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II) at Garching/Germany is equipped with a robot system based on a RX160 Stäubli robot, a Laser Tracker and a heavy basement. Samples up to 30kg can be investigated. Main restrictions are the available neutron flux, the detector efficiency and the detector size. Thus, the gauge volume is restricted to 1x1x1mm for ideal scattering conditions to measure in acceptable time scale. Photons with up to 200keV are known as high brilliant and high intense beam with similar penetration power than thermal neutrons. A typical set up of a high energy beamline for texture gradient investigations works without an Eulerian cradle so that restrictions in handling large sample are of less importance. The HZG materials science beamlines at Doris III and Petra III (Harwi-II@DorisIII and HEMS@PetraIII) are equipped with massif units for sample rotation and x-, y- and z- scanning for samples and additional equipments up to 200kg. Compared to thermal neutrons, which work with wavelengths between 1Å-2.5Å, the wavelength of high energy photons is small (0.05Å – 0.20Å). That leads on one hand to low scattering angles (1° - 10°) and on the other hand to an anisotropic ellipsoidal gauge volume. The local resolution of the synchrotron beam is much better than for thermal neutrons. In both methods corrections for constant gauge volume during pole figure scanning and for anisotropic absorption are of great importance.

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