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1

Synchronized dynamic dose reconstruction  

SciTech Connect

Variations in target volume position between and during treatment fractions can lead to measurable differences in the dose distribution delivered to each patient. Current methods to estimate the ongoing cumulative delivered dose distribution make idealized assumptions about individual patient motion based on average motions observed in a population of patients. In the delivery of intensity modulated radiation therapy (IMRT) with a multi-leaf collimator (MLC), errors are introduced in both the implementation and delivery processes. In addition, target motion and MLC motion can lead to dosimetric errors from interplay effects. All of these effects may be of clinical importance. Here we present a method to compute delivered dose distributions for each treatment beam and fraction, which explicitly incorporates synchronized real-time patient motion data and real-time fluence and machine configuration data. This synchronized dynamic dose reconstruction method properly accounts for the two primary classes of errors that arise from delivering IMRT with an MLC: (a) Interplay errors between target volume motion and MLC motion, and (b) Implementation errors, such as dropped segments, dose over/under shoot, faulty leaf motors, tongue-and-groove effect, rounded leaf ends, and communications delays. These reconstructed dose fractions can then be combined to produce high-quality determinations of the dose distribution actually received to date, from which individualized adaptive treatment strategies can be determined.

Litzenberg, Dale W.; Hadley, Scott W.; Tyagi, Neelam; Balter, James M.; Ten Haken, Randall K.; Chetty, Indrin J. [University of Michigan, Ann Arbor, Michigan 48109 (United States)

2007-01-15T23:59:59.000Z

2

Neutron dose equivalent meter  

DOE Patents (OSTI)

A neutron dose equivalent detector for measuring neutron dose capable of accurately responding to neutron energies according to published fluence to dose curves. The neutron dose equivalent meter has an inner sphere of polyethylene, with a middle shell overlying the inner sphere, the middle shell comprising RTV.RTM. silicone (organosiloxane) loaded with boron. An outer shell overlies the middle shell and comprises polyethylene loaded with tungsten. The neutron dose equivalent meter defines a channel through the outer shell, the middle shell, and the inner sphere for accepting a neutron counter tube. The outer shell is loaded with tungsten to provide neutron generation, increasing the neutron dose equivalent meter's response sensitivity above 8 MeV.

Olsher, Richard H. (Los Alamos, NM); Hsu, Hsiao-Hua (Los Alamos, NM); Casson, William H. (Los Alamos, NM); Vasilik, Dennis G. (Los Alamos, NM); Kleck, Jeffrey H. (Menlo Park, CA); Beverding, Anthony (Foster City, CA)

1996-01-01T23:59:59.000Z

3

Hanford Environmental Dose Reconstruction Project Monthly Report  

SciTech Connect

This monthly report summarizes the technical progress and project status for the Hanford Environmental Dose Reconstruction (HEDR) Project being conducted at the Pacific Northwest Laboratory (PNL) under the direction of a Technical Steering Panel (TSP). The TSP is composed of experts in numerous technical fields related to this project and represents the interests of the public. The objective of the Hanford Environmental Dose Reconstruction Project is to estimate the radiation doses that populations could have received from nuclear operations at Hanford since 1944. The project is being managed and conducted by the Pacific Northwest Laboratory (PNL) under the direction of an independent Technical Steering Panel (TSP). The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed, from release to impact on humans (dose estimates): source terms, environmental transport, environmental monitoring data, demographics, agriculture, food habits, and environmental pathways and dose estimates. 3 figs., 3 tabs.

Finch, S.M. (comp.)

1990-10-01T23:59:59.000Z

4

Hanford Environmental Dose Reconstruction Project monthly report  

SciTech Connect

The objective of the Hanford Environmental Dose Reconstruction MDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The TSP consists of experts in envirorunental pathways. epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering. radiation dosimetry. and cultural anthropology. Included are appointed members representing the states of Oregon, Washington, and Idaho, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact on humans (dose estimates): Source Terms; Environmental Transport; Environmental Monitoring Data Demography, Food Consumption, and Agriculture; and Environmental Pathways and Dose Estimates.

McMakin, A.H., Cannon, S.D.; Finch, S.M. (comps.) [comps.

1992-09-01T23:59:59.000Z

5

Dose-equivalent neutron dosimeter  

DOE Patents (OSTI)

A neutron dosimeter is disclosed which provides a single measurement indicating the amount of potential biological damage resulting from the neutron exposure of the wearer, for a wide range of neutron energies. The dosimeter includes a detecting sheet of track etch detecting material such as a carbonate plastic, for detecting higher energy neutrons, and a radiator layer contaning conversion material such as /sup 6/Li and /sup 10/B lying adjacent to the detecting sheet for converting moderate energy neutrons to alpha particles that produce tracks in the adjacent detecting sheet.

Griffith, R.V.; Hankins, D.E.; Tomasino, L.; Gomaa, M.A.M.

1981-01-07T23:59:59.000Z

6

Oak Ridge Dose Reconstruction Project Summary Report; Reports of the Oak Ridge Dose Reconstruction, Vol. 7  

SciTech Connect

In the early 1990s, concern about the Oak Ridge Reservation's past releases of contaminants to the environment prompted Tennessee's public health officials to pursue an in-depth study of potential off-site health effects at Oak Ridge. This study, the Oak Ridge dose reconstruction, was supported by an agreement between the U.S. Department of Energy (DOE) and the State of Tennessee, and was overseen by a 12-member panel of individuals appointed by Tennessee's Commissioner of Health. The panel requested that the principal investigator for the project prepare the following report, ''Oak Ridge Dose Reconstruction Project Summary Report,'' to serve the following purposes: (1) summarize in a single, less technical report, the methods and results of the various investigations that comprised the Phase II of the dose reconstruction; (2) describe the systematic searching of classified and unclassified historical records that was a vital component of the project; and (3) summarize the less detailed, screening-level assessments that were performed to evaluate the potential health significance of a number of materials, such a uranium, whose priority did not require a complete dose reconstruction effort. This report describes each major step of the dose reconstruction study: (1) the review of thousands of historical records to obtain information relating to past operations at each facility; (2) estimation of the quantity and timing of releases of radioiodines from X-10, of mercury from Y-12, of PCB's from all facilities, and of cesium-137 and other radionuclides from White Oak Creek; (3) evaluation of the routes taken by these contaminants through the environment to nearby populations; and (4) estimation of doses and health risks to exposed groups. Calculations found the highest excess cancer risks for a female born in 1952 who drank goat milk; the highest non-cancer health risk was for children in a farm family exposed to PCBs in and near East Fork Poplar Creek. More detailed dose and risk estimates, and associated uncertainties, are presented in several technical reports. One way to easily locate them in OSTI's Information Bridge is by searching the ''report number field'' for the number DOE/OR/21981*. The asterisk placed after the base number will enable the search to list all of the related reports in this series.

Thomas E. Widner; et. al.

1999-07-01T23:59:59.000Z

7

Software requirements specification for the Hanford Environmental Dose Reconstruction Project air pathway environmental accumulation and dose codes  

SciTech Connect

This report describes the general software requirements for the Hanford Reservation Dose reconstruction Project.

Not Available

1992-12-28T23:59:59.000Z

8

Multigroup neutron dose calculations for proton therapy  

SciTech Connect

We have developed tools for the preparation of coupled multigroup proton/neutron cross section libraries. Our method is to use NJOY to process evaluated nuclear data files for incident particles below 150 MeV and MCNPX to produce data for higher energies. We modified the XSEX3 program of the MCNPX code system to produce Legendre expansions of scattering matrices generated by sampling the physics models that are comparable to the output of the GROUPR routine of NJOY. Our code combines the low and high energy scattering data with user input stopping powers and energy deposition cross sections that we also calculated using MCNPX. Our code also calculates momentum transfer coefficients for the library and optionally applies an energy straggling model to the scattering cross sections and stopping powers. The motivation was initially for deterministic solution of space radiation shielding calculations using Attila, but noting that proton therapy treatment planning may neglect secondary neutron dose assessments because of difficulty and expense, we have also investigated the feasibility of multi group methods for this application. We have shown that multigroup MCNPX solutions for secondary neutron dose compare well with continuous energy solutions and are obtainable with less than half computational cost. This efficiency comparison neglects the cost of preparing the library data, but this becomes negligible when distributed over many multi group calculations. Our deterministic calculations illustrate recognized obstacles that may have to be overcome before discrete ordinates methods can be efficient alternatives for proton therapy neutron dose calculations.

Kelsey Iv, Charles T [Los Alamos National Laboratory; Prinja, Anil K [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

9

Errors and Uncertainties in Dose Reconstruction for Radiation Effects Research  

SciTech Connect

Dose reconstruction for studies of the health effects of ionizing radiation have been carried out for many decades. Major studies have included Japanese bomb survivors, atomic veterans, downwinders of the Nevada Test Site and Hanford, underground uranium miners, and populations of nuclear workers. For such studies to be credible, significant effort must be put into applying the best science to reconstructing unbiased absorbed doses to tissues and organs as a function of time. In many cases, more and more sophisticated dose reconstruction methods have been developed as studies progressed. For the example of the Japanese bomb survivors, the dose surrogate “distance from the hypocenter” was replaced by slant range, and then by TD65 doses, DS86 doses, and more recently DS02 doses. Over the years, it has become increasingly clear that an equal level of effort must be expended on the quantitative assessment of uncertainty in such doses, and to reducing and managing uncertainty. In this context, this paper reviews difficulties in terminology, explores the nature of Berkson and classical uncertainties in dose reconstruction through examples, and proposes a path forward for Joint Coordinating Committee for Radiation Effects Research (JCCRER) Project 2.4 that requires a reasonably small level of effort for DOSES-2008.

Strom, Daniel J.

2008-04-14T23:59:59.000Z

10

Quantifying dose to the reconstructed breast: Can we adequately treat?  

SciTech Connect

To evaluate how immediate reconstruction (IR) impacts postmastectomy radiotherapy (PMRT) dose distributions to the reconstructed breast (RB), internal mammary nodes (IMN), heart, and lungs using quantifiable dosimetric end points. 3D conformal plans were developed for 20 IR patients, 10 autologous reconstruction (AR), and 10 expander-implant (EI) reconstruction. For each reconstruction type, 5 right- and 5 left-sided reconstructions were selected. Two plans were created for each patient, 1 with RB coverage alone and 1 with RB + IMN coverage. Left-sided EI plans without IMN coverage had higher heart Dmean than left-sided AR plans (2.97 and 0.84 Gy, p = 0.03). Otherwise, results did not vary by reconstruction type and all remaining metrics were evaluated using a combined AR and EI dataset. RB coverage was adequate regardless of laterality or IMN coverage (Dmean 50.61 Gy, D95 45.76 Gy). When included, IMN Dmean and D95 were 49.57 and 40.96 Gy, respectively. Mean heart doses increased with left-sided treatment plans and IMN inclusion. Right-sided treatment plans and IMN inclusion increased mean lung V{sub 20}. Using standard field arrangements and 3D planning, we observed excellent coverage of the RB and IMN, regardless of laterality or reconstruction type. Our results demonstrate that adequate doses can be delivered to the RB with or without IMN coverage.

Chung, Eugene; Marsh, Robin B.; Griffith, Kent A.; Moran, Jean M. [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Pierce, Lori J., E-mail: ljpierce@umich.edu [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States)

2013-04-01T23:59:59.000Z

11

SRS Dose Reconstruction Report August 2006 EXECUTIVE SUMMARY  

E-Print Network (OSTI)

1954 to 1992, first by EI duPont de Nemours and Company (Dupont) for the U.S. Atomic Energy Commission (AEC), and later by Westinghouse Savannah River Company for DOE (1). SRS operated five reactors and two). ii #12;SRS Dose Reconstruction Report August 2006 Phase I of the study was a search of SRS to find

12

Phase 1 of the Hanford Environmental Dose Reconstruction Project  

SciTech Connect

For more than 40 years, the US government made plutonium for nuclear weapons at the Hanford Site in southeastern Washington State. Radioactive materials were released to both the air and water from Hanford. People could have been exposed to these materials, called radionuclides. The Hanford Environmental Dose Reconstruction (HEDR) Project is a multi-year scientific study to estimate the radiation doses the public may have received as a results of these releases. The study began in 1988. During the first phase, scientists began to develop and test methods for reconstructing the radiation doses. To do this, scientists found or reconstructed information about the amount and type of radionuclides that were released from Hadford facilities, where they traveled in environment, and how they reached people. Information about the people who could have been exposed was also found or reconstructed. Scientists then developed a computer model that can estimate doses from radiation exposure received many years ago. All the information that had been gathered was fed into the computer model. Then scientists did a test run'' to see whether the model was working properly. As part of its test run,'' scientists asked the computer model to generate two types of preliminary results: amounts of radionuclides in the environment (air, soil, pasture grass, food, and milk) and preliminary doses people could have received from all the routes of radiation exposure, called exposure pathways. Preliminary dose estimates were made for categories of people who shared certain characteristics and for the Phase 1 population as a whole. 26 refs., 48 figs.

Not Available

1990-07-20T23:59:59.000Z

13

Neutron source reconstruction from pinhole imaging at National Ignition Facility  

SciTech Connect

The neutron imaging system at the National Ignition Facility (NIF) is an important diagnostic tool for measuring the two-dimensional size and shape of the neutrons produced in the burning deuterium-tritium plasma during the ignition stage of inertial confinement fusion (ICF) implosions at NIF. Since the neutron source is small (?100 ?m) and neutrons are deeply penetrating (>3 cm) in all materials, the apertures used to achieve the desired 10-?m resolution are 20-cm long, single-sided tapers in gold. These apertures, which have triangular cross sections, produce distortions in the image, and the extended nature of the pinhole results in a non-stationary or spatially varying point spread function across the pinhole field of view. In this work, we have used iterative Maximum Likelihood techniques to remove the non-stationary distortions introduced by the aperture to reconstruct the underlying neutron source distributions. We present the detailed algorithms used for these reconstructions, the stopping criteria used and reconstructed sources from data collected at NIF with a discussion of the neutron imaging performance in light of other diagnostics.

Volegov, P.; Danly, C. R.; Grim, G. P.; Guler, N.; Merrill, F. E.; Wilde, C. H.; Wilson, D. C. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States); Fittinghoff, D. N.; Izumi, N.; Ma, T.; Warrick, A. L. [Livermore National Laboratory, Livermore, California 94550 (United States)] [Livermore National Laboratory, Livermore, California 94550 (United States)

2014-02-15T23:59:59.000Z

14

Decision management for the Hanford Environmental Dose Reconstruction Project  

SciTech Connect

The Hanford Environmental Dose Reconstruction (HEDR) Project is in the process of developing estimates for the radiation doses that individuals and population groups may have received as a result of past activities at the Hanford Reservation in Eastern Washington. A formal decision-aiding methodology has been developed to assist the HEDR Project in making significant and defensible decisions regarding how this study will be conducted. These decisions relate primarily to policy (e.g., the appropriate level of public participation in the study) and specific technical aspects (e.g., the appropriate domain and depth of the study), and may have significant consequences with respect to technical results, costs, and public acceptability.

Roberds, W.J.; Haerer, H.A. (Golder Associates, Inc., Redmond, WA (United States)); Winterfeldt, D.V. (Decision Insights, Laguna Beach, CA (United States))

1992-04-01T23:59:59.000Z

15

Photon doses in NPL standard neutron fields  

Science Journals Connector (OSTI)

......to 10 MeV according to the manufacturer's handbooks(2, 3). The EPD-Mk2 handbook states that the neutron response of the photon-sensitive element is 2 %. The EPD-N2 handbook does not give a value for the neutron response of......

N. J. Roberts; N. A. Horwood; C. J. McKay

2014-10-01T23:59:59.000Z

16

Photon doses in NPL standard neutron fields  

Science Journals Connector (OSTI)

......tubes and electronic personal...tubes and electronic personal...manufacturer's handbooks(2, 3...handbook does not give...neutron-photon-electron calculations were made...Scientific. Electronic personal dosemeter handbook, issue 9......

N. J. Roberts; N. A. Horwood; C. J. McKay

2014-10-01T23:59:59.000Z

17

Numerical characterization of a tomographic system for online dose measurements in Boron Neutron Capture Therapy  

SciTech Connect

A tomographic system for online dose measurements in Boron Neutron Capture Therapy (BNCT) based on the measurement of a specific 478 keV {gamma}-ray emitted after the neutron capture in boron is being developed. In the present work we study by means of Monte Carlo numerical simulations the effects of the finite spatial resolution and the limited number of counts, i. e. the statistical noise, on the reconstructed image contrast of numerical phantoms. These phantoms, of simple geometry, mimic the tumor (specific) and the normal tissue (non specific) boron concentrations. The simulated projection data were reconstructed using the expectation-maximization maximum-likelihood algorithm. These studies will help in the improvement of BNCT dosimetry.

Minsky, D. M.; Valda, A. A.; Somacal, H. [Escuela de Ciencia y Tecnologia (UNSAM), San Martin, Buenos Aires (Argentina); Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Burlon, A. A. [Escuela de Ciencia y Tecnologia (UNSAM), San Martin, Buenos Aires (Argentina); Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Fundacion J.B. Sauberan (Argentina); Kreiner, A. J. [Escuela de Ciencia y Tecnologia (UNSAM), San Martin, Buenos Aires (Argentina); Dpto. de Fisica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Buenos Aires (Argentina); CONICET (Argentina)

2007-02-12T23:59:59.000Z

18

Oak Ridge Dose Reconstruction annual report for calendar year 1997  

SciTech Connect

Calendar year 1997 was the third full year of work on the Oak Ridge Dose Reconstruction. Activities are summarized on the following individual project tasks: Task 1 -- Investigation of radioiodine releases from X-10 radioactive lanthanum processing; Task 2 -- Investigation of mercury releases from Y-12 lithium enrichment; Task 3 -- Investigation of PCBs in the environment near Oak Ridge; Task 4 -- Investigation of radionuclides released from White Oak Creek to the Clinch River; Task 5 -- Systematic searching of records repositories; Task 6 -- Evaluation of the quality of uranium monitoring data and a screening evaluation of potential off-site health risks; and Task 7 -- Performance of screening for additional materials not evaluated in the feasibility study.

NONE

1998-09-01T23:59:59.000Z

19

Solar modulation parameter for cosmic rays since 1936 reconstructed from groundbased neutron  

E-Print Network (OSTI)

Solar modulation parameter for cosmic rays since 1936 reconstructed from groundbased neutron the world network of sea level neutron monitors and covers the period since April 1964. The part between February 1951 and March 1964 is based on data from one to two mountain neutron monitors of IGY type

Usoskin, Ilya G.

20

Ground-water contribution to dose from past Hanford Operations. Hanford Environmental Dose Reconstruction Project  

SciTech Connect

The Hanford Environmental Dose Reconstruction (HEDR) Project is being conducted to estimate radiation doses that populations and individuals could have received from Hanford Site operations from 1944 to the present. Four possible pathways by which radionuclides migrating in ground water on the Hanford Site could have reached the public have been identified: (1) through contaminated ground water migrating to the Columbia River; (2) through wells on or adjacent to the Hanford Site; (3) through wells next to the Columbia River downstream of Hanford that draw some or all of their water from the river (riparian wells); and (4) through atmospheric deposition resulting in contamination of a small watershed that, in turn, results in contamination of a shallow well or spring by transport in the ground water. These four pathways make up the ``ground-water pathway,`` which is the subject of this study. Assessment of the ground-water pathway was performed by (1) reviewing the existing extensive literature on ground water and ground-water monitoring at Hanford and (2) performing calculations to estimate radionuclide concentrations where no monitoring data were collected. Radiation doses that would result from exposure to these radionuclides were calculated.

Freshley, M.D.; Thorne, P.D.

1992-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Development of Real-Time Measurement of Effective Dose for High Dose Rate Neutron Fields  

SciTech Connect

Studies of the effects of low doses of ionizing radiation require sources of radiation which are well characterized in terms of the dose and the quality of the radiation. One of the best measures of the quality of neutron irradiation is the dose mean lineal energy. At very low dose rates this can be determined by measuring individual energy deposition events, and calculating the dose mean of the event size. However, at the dose rates that are normally required for biology experiments, the individual events can not be separated by radiation detectors. However, the total energy deposited in a specified time interval can be measured. This total energy has a random variation which depends on the size of the individual events, so the dose mean lineal energy can be calculated from the variance of repeated measurements of the energy deposited in a fixed time. We have developed a specialized charge integration circuit for the measurement of the charge produced in a small ion chamber in typical neutron irradiation experiments. We have also developed 4.3 mm diameter ion chambers with both tissue equivalent and carbon walls for the purpose of measuring dose mean lineal energy due to all radiations and due to all radiations except neutrons, respectively. By adjusting the gas pressure in the ion chamber, it can be made to simulate tissue volumes from a few nanometers to a few millimeters in diameter. The charge is integrated for 0.1 seconds, and the resulting pulse height is recorded by a multi channel analyzer. The system has been used in a variety of photon and neutron radiation fields, and measured values of dose and dose mean lineal energy are consistent with values extrapolated from measurements made by other techniques at much lower dose rates. It is expected that this technique will prove to be much more reliable than extrapolations from measurements made at low dose rates because these low dose rate exposures generally do not accurately reproduce the attenuation and scattering environment of the actual radiation exposure.

L. A. Braby; W. D. Reece; W. H. Hsu

2003-08-29T23:59:59.000Z

22

Searching Effective Parameters for Low-Dose CT Reconstruction by Ant Colony Optimization  

E-Print Network (OSTI)

, Eric Papenhausen and Klaus Mueller Abstract-- Low-dose Computed Tomography (CT) has been gaining. To cope with the limited data collected at 30% of standard radiation, low-dose CT reconstruction algorithms generally require several iterations of forward projection, back-projection and regularization

Mueller, Klaus

23

Quantifying the Impact of Immediate Reconstruction in Postmastectomy Radiation: A Large, Dose-Volume Histogram-Based Analysis  

SciTech Connect

Purpose: To assess the impact of immediate breast reconstruction on postmastectomy radiation (PMRT) using dose-volume histogram (DVH) data. Methods and Materials: Two hundred forty-seven women underwent PMRT at our center, 196 with implant reconstruction and 51 without reconstruction. Patients with reconstruction were treated with tangential photons, and patients without reconstruction were treated with en-face electron fields and customized bolus. Twenty percent of patients received internal mammary node (IMN) treatment. The DVH data were compared between groups. Ipsilateral lung parameters included V20 (% volume receiving 20 Gy), V40 (% volume receiving 40 Gy), mean dose, and maximum dose. Heart parameters included V25 (% volume receiving 25 Gy), mean dose, and maximum dose. IMN coverage was assessed when applicable. Chest wall coverage was assessed in patients with reconstruction. Propensity-matched analysis adjusted for potential confounders of laterality and IMN treatment. Results: Reconstruction was associated with lower lung V20, mean dose, and maximum dose compared with no reconstruction (all P<.0001). These associations persisted on propensity-matched analysis (all P<.0001). Heart doses were similar between groups (P=NS). Ninety percent of patients with reconstruction had excellent chest wall coverage (D95 >98%). IMN coverage was superior in patients with reconstruction (D95 >92.0 vs 75.7%, P<.001). IMN treatment significantly increased lung and heart parameters in patients with reconstruction (all P<.05) but minimally affected those without reconstruction (all P>.05). Among IMN-treated patients, only lower lung V20 in those without reconstruction persisted (P=.022), and mean and maximum heart doses were higher than in patients without reconstruction (P=.006, P=.015, respectively). Conclusions: Implant reconstruction does not compromise the technical quality of PMRT when the IMNs are untreated. Treatment technique, not reconstruction, is the primary determinant of target coverage and normal tissue doses.

Ohri, Nisha [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Cordeiro, Peter G. [Department of Plastic Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Plastic Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Keam, Jennifer [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Ballangrud, Ase [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Shi Weiji; Zhang Zhigang [Department of Biostatistics and Epidemiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Biostatistics and Epidemiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Nerbun, Claire T.; Woch, Katherine M.; Stein, Nicholas F.; Zhou Ying [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); McCormick, Beryl; Powell, Simon N. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Ho, Alice Y., E-mail: HoA1234@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

2012-10-01T23:59:59.000Z

24

Cation disorder in high dose neutron irradiated spinel  

SciTech Connect

The crystal structures of MgAl{sub 2}O{sub 4} spinel single crystals irradiated to high neutron fluences (>5{center_dot}10{sup 26} n/m{sup 2} (E{sub n}>0.1 MeV)), were examined by neutron diffraction. Crystal structure refinement of the highest dose sample indicated that the average scattering strength of the tetrahedral crystal sites decreased by {approximately}20% while increasing by {approximately}8% on octahedral sites. Since the neutron scattering length for Mg is considerably larger than for Al, this result is consistent with site exchange between Mg{sup 2+} ions on tetrahedral sites and Al{sup 3+} ions on octahedral sites. Least squares refinements also indicated that in all irradiated samples, at least 35% of Mg{sup 2+} and Al{sup 3+} ions in the crystal experienced disordering replacements. This retained dpa on the cation sublattices is the largest retained damage ever measured in an irradiated spinel material.

Sickafus, K.E.; Larson, A.C.; Yu, N.; Nastasi, M. [Los Alamos National Lab., NM (United States); Hollenberg, G.W.; Garner, F.A. [Pacific Northwest Lab., Richland, WA (United States); Bradt, R.C. [Univ. of Nevada, Reno, NV (United States)

1994-06-01T23:59:59.000Z

25

Cation disorder in high-dose, neutron-irradiated spinel  

SciTech Connect

The objective of this effort is to determine whether MgAl{sub 2}O{sub 4} spinel is a suitable ceramic for fusion applications. Here, the crystal structures of MgAl{sub 2}O{sub 4} spinel single crystals irradiated to high neutron fluences [>5{center_dot}10{sup 26} n/m{sup 2} (E{sub n} > 0.1 MeV)] were examined by neutron diffraction. Crystal structure refinement of the highest dose sample indicated that the average scattering strength of the tetrahedral crystal sites decreased by {approximately} 20% while increasing by {approximately} 8% on octahedral sites. Since the neutron scattering length for Mg is considerably larger than for Al, this results is consistent with site exchange between Mg{sup 2+} ions on tetrahedral sites and Al{sup 3+} ions on octahedral sites. Least-squares refinements also indicated that, in all irradiated samples, at least 35% of Mg{sup 2+} and Al{sup 3+} ions in the crystal experienced disordering replacements. This retained dpa on the cation sublattices is the largest retained damage ever measured in an irradiated spinel material.

Sickafus, K.E.; Larson, A.C.; Yu, N.; Nastasi, M. [Los Alamos National Lab., NM (United States); Hollenberg, G.W.; Garner, F.A. [Pacific Northwest Lab., Richland, WA (United States); Bradt, R.C. [Univ. of Nevada, Reno, NV (United States)

1994-08-01T23:59:59.000Z

26

DOSE RATES FROM NEUTRON ACTIVATION OF FUSION REACTOR COMPONENTS  

E-Print Network (OSTI)

NEUTRON ACTIVATION OF FUSION REACTOR C01WONENTS LawrenceNeutron Activation of Fusion Reactor Components Lawrence

Ruby, Lawrence

2014-01-01T23:59:59.000Z

27

A method of dose reconstruction for moving targets compatible with dynamic treatments  

SciTech Connect

Purpose: To develop a method that allows a commercial treatment planning system (TPS) to perform accurate dose reconstruction for rigidly moving targets and to validate the method in phantom measurements for a range of treatments including intensity modulated radiation therapy (IMRT), volumetric arc therapy (VMAT), and dynamic multileaf collimator (DMLC) tracking. Methods: An in-house computer program was developed to manipulate Dicom treatment plans exported from a TPS (Eclipse, Varian Medical Systems) such that target motion during treatment delivery was incorporated into the plans. For each treatment, a motion including plan was generated by dividing the intratreatment target motion into 1 mm position bins and construct sub-beams that represented the parts of the treatment that were delivered, while the target was located within each position bin. For each sub-beam, the target shift was modeled by a corresponding isocenter shift. The motion incorporating Dicom plans were reimported into the TPS, where dose calculation resulted in motion including target dose distributions. For experimental validation of the dose reconstruction a thorax phantom with a moveable lung equivalent rod with a tumor insert of solid water was first CT scanned. The tumor insert was delineated as a gross tumor volume (GTV), and a planning target volume (PTV) was formed by adding margins. A conformal plan, two IMRT plans (step-and-shoot and sliding windows), and a VMAT plan were generated giving minimum target doses of 95% (GTV) and 67% (PTV) of the prescription dose (3 Gy). Two conformal fields with MLC leaves perpendicular and parallel to the tumor motion, respectively, were generated for DMLC tracking. All treatment plans were delivered to the thorax phantom without tumor motion and with a sinusoidal tumor motion. The two conformal fields were delivered with and without portal image guided DMLC tracking based on an embedded gold marker. The target dose distribution was measured with a radiochromic film in the moving rod and compared with the reconstructed doses using gamma tests. Results: Considerable interplay effects between machine motion and target motion were observed for the treatments without tracking. For nontracking experiments, the mean 2 mm/2% gamma pass rate over all investigated scenarios was 99.6% between calculated and measured doses. For tracking experiments, the mean gamma pass rate was 99.4%. Conclusions: A method for accurate dose reconstruction for moving targets with dynamic treatments was developed and experimentally validated in a variety of delivery scenarios. The method is suitable for integration into TPSs, e.g., for reconstruction of the dose delivered to moving tumors or calculation of target doses delivered with DMLC tracking.

Rugaard Poulsen, Per; Lykkegaard Schmidt, Mai; Keall, Paul; Schjodt Worm, Esben; Fledelius, Walther; Hoffmann, Lone [Department of Oncology, Aarhus University Hospital, Norrebrogade 44, 8000 Aarhus C, Institute of Clinical Medicine, Aarhus University, Brendstrupgaardsvej 100, 8200 Aarhus N (Denmark); Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C (Denmark); Radiation Physics Laboratory, Sydney Medical School, University of Sydney, NSW 2006 (Australia); Department of Oncology, Aarhus University Hospital, Norrebrogade 44, 8000 Aarhus C, Department of Medical Physics, Aarhus University Hospital, Norrebrogade 44, 8000 Aarhus C (Denmark); Department of Oncology, Aarhus University Hospital, Norrebrogade 44, 8000 Aarhus C (Denmark); Department of Medical Physics, Aarhus University Hospital, Norrebrogade 44, 8000 Aarhus C (Denmark)

2012-10-15T23:59:59.000Z

28

Impact of the Revised 10 CFR 835 on the Neutron Dose Rates at LLNL  

SciTech Connect

In June 2007, 10 CFR 835 [1] was revised to include new radiation weighting factors for neutrons, updated dosimetric models, and dose terms consistent with the newer ICRP recommendations. A significant aspect of the revised 10 CFR 835 is the adoption of the recommendations outlined in ICRP-60 [2]. The recommended new quantities demand a review of much of the basic data used in protection against exposure to sources of ionizing radiation. The International Commission on Radiation Units and Measurements has defined a number of quantities for use in personnel and area monitoring [3,4,5] including the ambient dose equivalent H*(d) to be used for area monitoring and instrument calibrations. These quantities are used in ICRP-60 and ICRP-74. This report deals only with the changes in the ambient dose equivalent and ambient dose rate equivalent for neutrons as a result of the implementation of the revised 10 CFR 835. In the report, the terms neutron dose and neutron dose rate will be used for convenience for ambient neutron dose and ambient neutron dose rate unless otherwise stated. This report provides a qualitative and quantitative estimate of how much the neutron dose rates at LLNL will change with the implementation of the revised 10 CFR 835. Neutron spectra and dose rates from selected locations at the LLNL were measured with a high resolution spectroscopic neutron dose rate system (ROSPEC) as well as with a standard neutron rem meter (a.k.a., a remball). The spectra obtained at these locations compare well with the spectra from the Radiation Calibration Laboratory's (RCL) bare californium source that is currently used to calibrate neutron dose rate instruments. The measurements obtained from the high resolution neutron spectrometer and dose meter ROSPEC and the NRD dose meter compare within the range of {+-}25%. When the new radiation weighting factors are adopted with the implementation of the revised 10 CFR 835, the measured dose rates will increase by up to 22%. The health physicists should consider this increase for any areas that have dose rates near a posting limit, such as near the 100 mrem/hr for a high radiation area, as this increase in measured dose rate may result in some changes to postings and consequent radiological controls.

Radev, R

2009-01-13T23:59:59.000Z

29

Image reconstruction and the effect on dose calculation for hip prostheses  

SciTech Connect

High atomic number inserts, such as hip prostheses and dental fillings, cause streak artifacts on computed tomography (CT) images when filtered back-projection (FBP) methods are used. These streak artifacts severely degrade our ability to differentiate the tumor volume. Also, incorrect Hounsfield numbers yield incorrect electron density information that may lead to erroneous dose calculations, and, as a result, compromise clinical outcomes. The aim of this research was to evaluate the dosimetric consequences of artifacts during radiotherapy planning of a prostate patient containing a hip prosthesis. The CT numbers corresponding to an iron prosthesis were inserted into the right femoral head of an existing CT image set. This artifact-free image was used as the standard image set. CT projections through the image set formed the sinogram, from which filtered back projection and iterative deblurring methods were used to create reconstructed image sets. These reconstructed image sets contained artifacts. Prostate treatment plans were then calculated using a Monte Carlo system for the standard and reconstructed CT image sets. Close to the prosthesis, the CT numbers between the reconstructed and standard image sets differed substantially. However, because the CT number differences covered only a small area, the dose distributions on the reconstructed and standard image sets were not significantly different. The dose-volume histograms for the prostate, rectum, and bladder were virtually identical. Our results indicate that even though CT image artifacts restrict our ability to differentiate tumors and critical structures, the dose distributions for a prostate plan containing a hip prosthesis, calculated on both artifact-free image sets and image sets containing artifacts, are not significantly different.

Keall, Paul J.; Chock, Leah B.; Jeraj, Robert; Siebers, Jeffrey V.; Mohan, Radhe

2003-06-30T23:59:59.000Z

30

Columbia River Pathway Dosimetry Report, 1944-1992. Hanford Environmental Dose Reconstruction Project  

SciTech Connect

The purpose of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation dose that individuals could have received as a result of radionuclide emissions since 1944 from the Hanford Site. One objective of the HEDR Project is to estimate doses to individuals who were exposed to the radionuclides released to the Columbia River (the river pathway). This report documents the last in a series of dose calculations conducted on the Columbia River pathway. The report summarizes the technical approach used to estimate radiation doses to three classes of representative individuals who may have used the Columbia River as a source of drinking water, food, or for recreational or occupational purposes. In addition, the report briefly explains the approaches used to estimate the radioactivity released to the river, the development of the parameters used to model the uptake and movement of radioactive materials in aquatic systems such as the Columbia River, and the method of calculating the Columbia River`s transport of radioactive materials. Potential Columbia River doses have been determined for representative individuals since the initiation of site activities in 1944. For this report, dose calculations were performed using conceptual models and computer codes developed for the purpose of estimating doses. All doses were estimated for representative individuals who share similar characteristics with segments of the general population.

Farris, W.T.; Napier, B.A.; Simpson, J.C.; Snyder, S.F.; Shipler, D.B.

1994-04-01T23:59:59.000Z

31

VMAT QA: Measurement-guided 4D dose reconstruction on a patient  

SciTech Connect

Purpose: To develop and validate a volume-modulated arc therapy (VMAT) quality assurance (QA) tool that takes as input a time-resolved, low-density ({approx}10 mm) cylindrical surface dose map from a commercial helical diode array, and outputs a high density, volumetric, time-resolved dose matrix on an arbitrary patient dataset. This first validation study is limited to a homogeneous 'patient.'Methods: A VMAT treatment is delivered to a diode array phantom (ARCCHECK, Sun Nuclear Corp., Melbourne, FL). 3DVH software (Sun Nuclear) derives the high-density volumetric dose using measurement-guided dose reconstruction (MGDR). MGDR cylindrical phantom results are then used to perturb the three-dimensional (3D) treatment planning dose on the patient dataset, producing a semiempirical volumetric dose grid. Four-dimensional (4D) dose reconstruction on the patient is also possible by morphing individual sub-beam doses instead of the composite. For conventional (3D) dose comparison two methods were developed, using the four plans (Multi-Target, C-shape, Mock Prostate, and Head and Neck), including their structures and objectives, from the AAPM TG-119 report. First, 3DVH and treatment planning system (TPS) cumulative point doses were compared to ion chamber in a cube water-equivalent phantom ('patient'). The shape of the phantom is different from the ARCCHECK and furthermore the targets were placed asymmetrically. Second, coronal and sagittal absolute film dose distributions in the cube were compared with 3DVH and TPS. For time-resolved (4D) comparisons, three tests were performed. First, volumetric dose differences were calculated between the 3D MGDR and cumulative time-resolved patient (4D MGDR) dose at the end of delivery, where they ideally should be identical. Second, time-resolved (10 Hz sampling rate) ion chamber doses were compared to cumulative point dose vs time curves from 4D MGDR. Finally, accelerator output was varied to assess the linearity of the 4D MGDR with global fluence change. Results: Across four TG-119 plans, the average PTV point dose difference in the cube between 3DVH and ion chamber is 0.1 {+-} 1.0%. Average film vs TPS {gamma}-analysis passing rates are 83.0%, 91.1%, and 98.4% for 1%/2 mm, 2%/2 mm, and 3%/3 mm threshold combinations, respectively, while average film vs 3DVH {gamma}-analysis passing rates are 88.6%, 96.1%, and 99.5% for the same respective criteria. 4D MGDR was also sufficiently accurate. First, for 99.5% voxels in each case, the doses from 3D and 4D MGDR at the end of delivery agree within 0.5%local dose-error/1 mm distance. Moreover, all failing voxels are confined to the edge of the cylindrical reconstruction volume. Second, dose vs time curves track between the ion chamber and 4D MGDR within 1%. Finally, 4D MGDR dose changes linearly with the accelerator output: the difference between cumulative ion chamber and MGDR dose changed by no more than 1% (randomly) with the output variation range of 10%. Conclusions: Even for a well-commissioned TPS, comparison metrics show better agreement on average to MGDR than to TPS on the arbitrary-shaped measurable 'patient.' The method requires no more accelerator time than standard QA, while producing more clinically relevant information. Validation in a heterogeneous thoracic phantom is under way, as is the ultimate application of 4D MGDR to virtual motion studies.

Nelms, Benjamin E.; Opp, Daniel; Robinson, Joshua; Wolf, Theresa K.; Zhang, Geoffrey; Moros, Eduardo; Feygelman, Vladimir [Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612 (United States); Department of Physics, University of South Florida, Tampa, Florida 33612 (United States); Live Oak Technologies LLC, Kirkwood, Missouri 63122 (United States); Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612 (United States)

2012-07-15T23:59:59.000Z

32

3D Reconstruction of Intricate Archean Microbial Structures Using Neutron Computed Tomography and Serial SectioningIN43B-0331 Abstract Project Goals  

E-Print Network (OSTI)

Tomography and Serial SectioningIN43B-0331 Abstract Project Goals Background Methods Neutron Computed using both serial sectioning and neutron computed tomography (NCT). Reconstruction techniques vary mechanisms for ancient microbial communities Neutron Computed Tomography Serial Sectioning Samples were

Hamann, Bernd

33

FY 1991 project plan for the Hanford Environmental Dose Reconstruction Project, Phase 2  

SciTech Connect

Phase 1 of the Hanford Environmental Dose Reconstruction Project was designed to develop and demonstrate a method for estimating radiation doses people may have received from Hanford Site operations since 1944. The method researchers developed relied on a variety of measured and reconstructed data as input to a modular computer model that generates dose estimates and their uncertainties. As part of Phase 1, researchers used the reconstructed data and computer model to calculate preliminary dose estimates for populations in a limited geographical area and time period. Phase 2, now under way, is designed to evaluate the Phase 1 data and model and improve them to calculate more accurate and precise dose estimates. Phase 2 will also be used to obtain preliminary estimates of two categories of doses: for Native American tribes and for individuals included in the pilot phase of the Hanford Thyroid Disease Study (HTDS). TSP Directive 90-1 required HEDR staff to develop Phase 2 task plans for TSP approval. Draft task plans for Phase 2 were submitted to the TSP at the October 11--12, 1990 public meeting, and, after discussions of each activity and associated budget needs, the TSP directed HEDR staff to proceed with a slate of specific project activities for FY 1991 of Phase 2. This project plan contains detailed information about those activities. Phase 2 is expected to last 15--18 months. In mid-FY 1991, project activities and budget will be reevaluated to determine whether technical needs or priorities have changed. Separate from, but related to, this project plan, will be an integrated plan for the remainder of the project. HEDR staff will work with the TSP to map out a strategy that clearly describes end products'' for the project and the work necessary to complete them. This level of planning will provide a framework within which project decisions in Phases 2, 3, and 4 can be made.

Not Available

1991-02-01T23:59:59.000Z

34

Calculation of Ambient (H*(10)) and Personal (Hp(10)) Dose Equivalent from a 252Cf Neutron Source  

SciTech Connect

The purpose of this calculation is to calculate the neutron dose factors for the Sr-Cf-3000 neutron source that is located in the 318 low scatter room (LSR). The dose factors were based on the dose conversion factors published in ICRP-21 Appendix 6, and the Ambient dose equivalent (H*(10)) and Personal dose equivalent (Hp(10)) dose factors published in ICRP Publication 74.

Traub, Richard J.

2010-03-26T23:59:59.000Z

35

A Fast local Reconstruction algorithm by selective backprojection for Low-Dose in Dental Computed Tomography  

E-Print Network (OSTI)

High radiation dose in computed tomography (CT) scans increases the lifetime risk of cancer, which become a major clinical concern. The backprojection-filtration (BPF) algorithm could reduce radiation dose by reconstructing images from truncated data in a short scan. In dental CT, it could reduce radiation dose for the teeth by using the projection acquired in a short scan, and could avoid irradiation to other part by using truncated projection. However, the limit of integration for backprojection varies per PI-line, resulting in low calculation efficiency and poor parallel performance. Recently, a tent BPF (T-BPF) has been proposed to improve calculation efficiency by rearranging projection. However, the memory-consuming data rebinning process is included. Accordingly, the chose-BPF (C-BPF) algorithm is proposed in this paper. In this algorithm, the derivative of projection is backprojected to the points whose x coordinate is less than that of the source focal spot to obtain the differentiated backprojection...

Bin, Yan; Yu, Han; Feng, Zhang; Chao, Wang Xian; Lei, Li

2013-01-01T23:59:59.000Z

36

Air pathway report: Phase I of the Hanford Environmental Dose Reconstruction Project  

SciTech Connect

Phase 1 of the air-pathway portion of the Hanford Environmental Dose Reconstruction (HEDR) Project sought to determine whether dose estimates could be calculated for populations in the 10 counties nearest the Hanford Site from atmospheric releases of iodine-131 from the site from 1944--1947. Phase 1 demonstrated the following: HEDR-calculated source-term estimates of iodine-131 releases to the atmosphere were within 20% of previously published estimates; calculated vegetation concentrations of iodine-131 agree well with previously published measurements; the highest of the Phase 1 preliminary dose estimates to the thyroid are consistent with independent, previously published estimates of doses to maximally exposed individuals; and, relatively crude, previously published measurements of thyroid burdens for Hanford workers are in the range of average burdens that the HEDR model estimated for similar reference individuals'' for the period 1944--1947. Preliminary median dose estimates summed over the year 1945--1947 for the primary pathway, air-pasture-cow-milk-thyroid, ranged from low median values of 0.006 rad for upwind adults who obtained milk from backyard cows not on pasture to high median values of 68.0 rad for downwind infants who drank milk from pasture-fed cows. Extremes of the estimated range are a low of essentially zero to upwind adults and a high of almost 3000 rem to downwind infants. 37 refs., 37 figs., 2 tabs.

Not Available

1991-07-01T23:59:59.000Z

37

Individualized 3D Reconstruction of Normal Tissue Dose for Patients With Long-term Follow-up: A Step Toward Understanding Dose Risk for Late Toxicity  

SciTech Connect

Purpose: Understanding the relationship between normal tissue dose and delayed radiation toxicity is an important component of developing more effective radiation therapy. Late outcome data are generally available only for patients who have undergone 2-dimensional (2D) treatment plans. The purpose of this study was to evaluate the accuracy of 3D normal tissue dosimetry derived from reconstructed 2D treatment plans in Hodgkin's lymphoma (HL) patients. Methods and Materials: Three-dimensional lung, heart, and breast volumes were reconstructed from 2D planning radiographs for HL patients who received mediastinal radiation therapy. For each organ, a reference 3D organ was modified with patient-specific structural information, using deformable image processing software. Radiation therapy plans were reconstructed by applying treatment parameters obtained from patient records to the reconstructed 3D volumes. For each reconstructed organ mean dose (D{sub mean}) and volumes covered by at least 5 Gy (V{sub 5}) and 20Gy (V{sub 20}) were calculated. This process was performed for 15 patients who had both 2D and 3D planning data available to compare the reconstructed normal tissue doses with those derived from the primary CT planning data and also for 10 historically treated patients with only 2D imaging available. Results: For patients with 3D planning data, the normal tissue doses could be reconstructed accurately using 2D planning data. Median differences in D{sub mean} between reconstructed and actual plans were 0.18 Gy (lungs), -0.15 Gy (heart), and 0.30 Gy (breasts). Median difference in V{sub 5} and V{sub 20} were less than 2% for each organ. Reconstructed 3D dosimetry was substantially higher in historical mantle-field treatments than contemporary involved-field mediastinal treatments: average D{sub mean} values were 15.2 Gy vs 10.6 Gy (lungs), 27.0 Gy vs 14.3 Gy (heart), and 8.0 Gy vs 3.2 Gy (breasts). Conclusions: Three-dimensional reconstruction of absorbed dose to organs at risk can be estimated accurately many years after exposure by using limited 2D data. Compared to contemporary involved-field treatments, normal tissue doses were significantly higher in historical mantle-field treatments. These methods build capacity to quantify the relationship between 3D normal tissue dose and observed late effects.

Ng, Angela [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada)] [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Brock, Kristy K.; Sharpe, Michael B. [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada) [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Moseley, Joanne L. [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada)] [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Craig, Tim [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada) [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Hodgson, David C., E-mail: David.Hodgson@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada)

2012-11-15T23:59:59.000Z

38

Microsoft Word - Y12NeutronDoseFinalDraft.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

2 - Neutron Radiation 2 - Neutron Radiation G.D. Kerr 1 , E.L. Frome 2 , W.G. Tankersley 3 , and J.P. Watkins 3 ORAU Technical Report # 2004-1406 1 Kerr Consulting Company 2 Computer Science and Mathematics Division, Oak Ridge National Laboratory 3 Center for Epidemiologic Research, Oak Ridge Associated Universities This work was done under Contract No. 200-2002-00593 with the National Institute for Occupational Safety and Health. 2 Table of Contents List of Figures .................................................................................................................3 List of Tables ..................................................................................................................4 Acknowledgement ..........................................................................................................5

39

Estimation of low-level neutron dose-equivalent rate by using extrapolation method for a curie level Am–Be neutron source  

Science Journals Connector (OSTI)

Abstract Neutron radiation protection is an important research area because of the strong radiation biological effect of neutron field. The radiation dose of neutron is closely related to the neutron energy, and the connected relationship is a complex function of energy. For the low-level neutron radiation field (e.g. the Am–Be source), the commonly used commercial neutron dosimeter cannot always reflect the low-level dose rate, which is restricted by its own sensitivity limit and measuring range. In this paper, the intensity distribution of neutron field caused by a curie level Am–Be neutron source was investigated by measuring the count rates obtained through a 3He proportional counter at different locations around the source. The results indicate that the count rates outside of the source room are negligible compared with the count rates measured in the source room. In the source room, 3He proportional counter and neutron dosimeter were used to measure the count rates and dose rates respectively at different distances to the source. The results indicate that both the count rates and dose rates decrease exponentially with the increasing distance, and the dose rates measured by a commercial dosimeter are in good agreement with the results calculated by the Geant4 simulation within the inherent errors recommended by ICRP and IEC. Further studies presented in this paper indicate that the low-level neutron dose equivalent rates in the source room increase exponentially with the increasing low-energy neutron count rates when the source is lifted from the shield with different radiation intensities. Based on this relationship as well as the count rates measured at larger distance to the source, the dose rates can be calculated approximately by the extrapolation method. This principle can be used to estimate the low level neutron dose values in the source room which cannot be measured directly by a commercial dosimeter.

Gang Li; Jiayun Xu; Jie Zhang

2015-01-01T23:59:59.000Z

40

Measurement of routinely encountered neutron field doses using portable survey instruments and a Bonner multisphere system  

E-Print Network (OSTI)

against two 10 Ci PuBe neutron sources. Measurements were m de at a research reactor facility and a cyclotron facility using a Victoreen 4BBA portable survey instrument, a Ludlum Mode1 15 portable survey instrument and a Bonner multisphere system. Data... Detector Response as a Function of Neutron Energy Page Figure 2. Plot of BON25G Spectral Output Figure 3, Flux-to-Dose Rate Conversion Factors for Neutrons . . . . 8 Figure 4. Data Measurement Locations at NSC 13 Figure 5. Data Measurement Locations...

Davis, Donald Reed

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Boron Neutron Capture Therapy (BNCT) Dose Calculation using Geometrical Factors Spherical Interface for Glioblastoma Multiforme  

SciTech Connect

Boron Neutron Capture Therapy (BNCT) is a cancer therapy by utilizing thermal neutron to produce alpha particles and lithium nuclei. The superiority of BNCT is that the radiation effects could be limited only for the tumor cells. BNCT radiation dose depends on the distribution of boron in the tumor. Absorbed dose to the cells from the reaction 10B (n, {alpha}) 7Li was calculated near interface medium containing boron and boron-free region. The method considers the contribution of the alpha particle and recoiled lithium particle to the absorbed dose and the variation of Linear Energy Transfer (LET) charged particles energy. Geometrical factor data of boron distribution for the spherical surface is used to calculate the energy absorbed in the tumor cells, brain and scalp for case Glioblastoma Multiforme. The result shows that the optimal dose in tumor is obtained for boron concentrations of 22.1 mg {sup 10}B/g blood.

Zasneda, Sabriani; Widita, Rena [Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha No. 10 Bandung, 40132 (Indonesia)

2010-06-22T23:59:59.000Z

42

Radionuclide neutron sources in calibration laboratory—neutron and gamma doses and their changes in time  

Science Journals Connector (OSTI)

......radiation require the determination of this component...been applied for the determination of neutron ambient...equivalent rate and for the determination of neutron and gamma...nominal decay of the main isotope. After 15-20 y...blocks, enclosing the boron or helium proportional......

K. Józefowicz; N. Golnik; P. Tulik; M. Zielczynski

2007-08-01T23:59:59.000Z

43

ACDOS2: an improved neutron-induced dose rate code  

SciTech Connect

To calculate the expected dose rate from fusion reactors as a function of geometry, composition, and time after shutdown a computer code, ACDOS2, was written, which utilizes up-to-date libraries of cross-sections and radioisotope decay data. ACDOS2 is in ANSI FORTRAN IV, in order to make it readily adaptable elsewhere.

Lagache, J.C.

1981-06-01T23:59:59.000Z

44

Data model description for the DESCARTES and CIDER codes. Hanford Environmental Dose Reconstruction Project  

SciTech Connect

The primary objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation dose that individuals could have received as a result of emissions since 1944 from the US Department of Energy`s (DOE) Hanford Site near Richland, Washington. One of the major objectives of the HEDR Project is to develop several computer codes to model the airborne releases. transport and envirorunental accumulation of radionuclides resulting from Hanford operations from 1944 through 1972. In July 1992, the HEDR Project Manager determined that the computer codes being developed (DESCARTES, calculation of environmental accumulation from airborne releases, and CIDER, dose calculations from environmental accumulation) were not sufficient to create accurate models. A team of HEDR staff members developed a plan to assure that computer codes would meet HEDR Project goals. The plan consists of five tasks: (1) code requirements definition. (2) scoping studies, (3) design specifications, (4) benchmarking, and (5) data modeling. This report defines the data requirements for the DESCARTES and CIDER codes.

Miley, T.B.; Ouderkirk, S.J.; Nichols, W.E.; Eslinger, P.W.

1993-01-01T23:59:59.000Z

45

Measurements of gamma dose and thermal neutron fluence in phantoms exposed to a BNCT epithermal beam with TLD-700  

Science Journals Connector (OSTI)

......epithermal neutron beam for boron neutron capture therapy...separation. INTRODUCTION Boron neutron capture therapy...accumulation of the isotope 10B in tumour tissue...necessary and that for the determination of the ratio R n, a...Carrara M., Borroni M. Determination of gamma dose and thermal......

G. Gambarini; D. Magni; V. Regazzoni; M. Borroni; M. Carrara; E. Pignoli; J. Burian; M. Marek; V. Klupak; L. Viererbl

2014-10-01T23:59:59.000Z

46

Secondary neutron doses in proton therapy treatments of ocular melanoma and craniopharyngioma  

Science Journals Connector (OSTI)

......as the non-treated eye, the healthy brain tissue etc. and these should be taken...Non-treated eye 11.42 10.64 121.5 Brain 4.55 8.09 36.8 Thyroid 3.33 8...neutron absorbed doses received by the brain (1.5 microGy Gy1) and three times lower......

J. Farah; R. Sayah; F. Martinetti; L. Donadille; V. Lacoste; J. Hérault; S. Delacroix; C. Nauraye; I. Vabre; C. Lee; W. E. Bolch; I. Clairand

2014-10-01T23:59:59.000Z

47

Clinical implementation of a digital tomosynthesis-based seed reconstruction algorithm for intraoperative postimplant dose evaluation in low dose rate prostate brachytherapy  

SciTech Connect

Purpose: The low dose rate brachytherapy procedure would benefit from an intraoperative postimplant dosimetry verification technique to identify possible suboptimal dose coverage and suggest a potential reimplantation. The main objective of this project is to develop an efficient, operator-free, intraoperative seed detection technique using the imaging modalities available in a low dose rate brachytherapy treatment room. Methods: This intraoperative detection allows a complete dosimetry calculation that can be performed right after an I-125 prostate seed implantation, while the patient is still under anesthesia. To accomplish this, a digital tomosynthesis-based algorithm was developed. This automatic filtered reconstruction of the 3D volume requires seven projections acquired over a total angle of 60 deg. with an isocentric imaging system. Results: A phantom study was performed to validate the technique that was used in a retrospective clinical study involving 23 patients. In the patient study, the automatic tomosynthesis-based reconstruction yielded seed detection rates of 96.7% and 2.6% false positives. The seed localization error obtained with a phantom study is 0.4{+-}0.4 mm. The average time needed for reconstruction is below 1 min. The reconstruction algorithm also provides the seed orientation with an uncertainty of 10 deg. {+-}8 deg. The seed detection algorithm presented here is reliable and was efficiently used in the clinic. Conclusions: When combined with an appropriate coregistration technique to identify the organs in the seed coordinate system, this algorithm will offer new possibilities for a next generation of clinical brachytherapy systems.

Brunet-Benkhoucha, Malik; Verhaegen, Frank; Lassalle, Stephanie; Beliveau-Nadeau, Dominic; Reniers, Brigitte; Donath, David; Taussky, Daniel; Carrier, Jean-Francois [Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada) and Departement de Radio-Oncologie, Centre Hospitalier de l'Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada); Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada) and Department of Radiation Oncology (MAASTRO), GROW Research Institute, University Medical Centre Maastricht, Maastricht (Netherlands); Departement de Radio-Oncologie, Centre Hospitalier de l'Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada); Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada) and Department of Radiation Oncology (MAASTRO), GROW Research Institute, University Medical Centre Maastricht, Maastricht (Netherlands); Departement de Radio-Oncologie, Centre Hospitalier de l'Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada); Departement de Radio-Oncologie, Centre Hospitalier de l'Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada) and CRCHUM, Centre Hospitalier de l'Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada)

2009-11-15T23:59:59.000Z

48

Measurements of neutron dose equivalent for a proton therapy center using uniform scanning proton beams  

SciTech Connect

Purpose: Neutron exposure is of concern in proton therapy, and varies with beam delivery technique, nozzle design, and treatment conditions. Uniform scanning is an emerging treatment technique in proton therapy, but neutron exposure for this technique has not been fully studied. The purpose of this study is to investigate the neutron dose equivalent per therapeutic dose, H/D, under various treatment conditions for uniform scanning beams employed at our proton therapy center. Methods: Using a wide energy neutron dose equivalent detector (SWENDI-II, ThermoScientific, MA), the authors measured H/D at 50 cm lateral to the isocenter as a function of proton range, modulation width, beam scanning area, collimated field size, and snout position. They also studied the influence of other factors on neutron dose equivalent, such as aperture material, the presence of a compensator, and measurement locations. They measured H/D for various treatment sites using patient-specific treatment parameters. Finally, they compared H/D values for various beam delivery techniques at various facilities under similar conditions. Results: H/D increased rapidly with proton range and modulation width, varying from about 0.2 mSv/Gy for a 5 cm range and 2 cm modulation width beam to 2.7 mSv/Gy for a 30 cm range and 30 cm modulation width beam when 18 Multiplication-Sign 18 cm{sup 2} uniform scanning beams were used. H/D increased linearly with the beam scanning area, and decreased slowly with aperture size and snout retraction. The presence of a compensator reduced the H/D slightly compared with that without a compensator present. Aperture material and compensator material also have an influence on neutron dose equivalent, but the influence is relatively small. H/D varied from about 0.5 mSv/Gy for a brain tumor treatment to about 3.5 mSv/Gy for a pelvic case. Conclusions: This study presents H/D as a function of various treatment parameters for uniform scanning proton beams. For similar treatment conditions, the H/D value per uncollimated beam size for uniform scanning beams was slightly lower than that from a passive scattering beam and higher than that from a pencil beam scanning beam, within a factor of 2. Minimizing beam scanning area could effectively reduce neutron dose equivalent for uniform scanning beams, down to the level close to pencil beam scanning.

Zheng Yuanshui; Liu Yaxi; Zeidan, Omar; Schreuder, Andries Niek; Keole, Sameer [ProCure Proton Therapy Center, 5901 West Memorial Road, Oklahoma City, Oklahoma 73142 (United States); INTEGRIS Cancer Insititute, 5911 West Memorial Road, Oklahoma City, Oklahoma 73142 (United States); ProCure Proton Therapy Center, 5901 West Memorial Road, Oklahoma City, Oklahoma 73142 (United States); ProCure Treatment Centers, 420 North Walnut Street, Bloomington, Indiana 47404 (United States); ProCure Proton Therapy Center, 5901 West Memorial Road, Oklahoma City, Oklahoma 73142 (United States)

2012-06-15T23:59:59.000Z

49

Overview of vegetation monitoring data, 1952--1983. Hanford Environmental Dose Reconstruction Project  

SciTech Connect

This report is a result of the Hanford Environmental Dose Reconstruction (HEDR) Project. The goal of the HEDR Project is to estimate the radiation dose that individuals could have received from emissions since 1944 at the Hanford Site near Richland, Washington. Members of the HEDR Project`s Environmental Monitoring Data Task have developed databases of historical environmental measurements of such emissions. The HEDR Project is conducted by Battelle, Pacific Northwest Laboratories. This report is the third in a series that documents the information available on measurements of iodine-131 concentrations in vegetation. The first two reports provide the data for 1945--1951. This report provides an overview of the historical documents, which contain vegetation data for 1952--1983. The overview is organized according to the documents available for any given year. Each section, covering one year, contains a discussion of the media sampled, the sampling locations, significant events if there were any, emission quantities, constituents measured, and a list of the documents with complete reference information. Because the emissions which affected vegetation were significantly less after 1951, the vegetation monitoring data after that date have not been used in the HEDR Project. However, access to these data may be of interest to the public. This overview is, therefore, being published.

Duncan, J.P.

1994-03-01T23:59:59.000Z

50

Neutron/gamma dose separation by the multiple-ion-chamber technique  

SciTech Connect

Many mixed n/..gamma.. dosimetry systems rely on two dosimeters, one composed of a tissue-equivalent material and the other made from a non-hydrogenous material. The paired chamber technique works well in fields of neutron radiation nearly identical in spectral composition to that in which the dosimeters were calibrated. However, this technique is drastically compromised in phantom due to the degradation of the neutron spectrum. The three-dosimeter technique allows for the fall-off in neutron sensitivity of the two non-hydrogenous dosimeters. Precise and physically meaningful results were obtained with this technique with a D-T source in air and in phantom and with simultaneous D-T neutron and /sup 60/Co gamma ray irradiation in air. The MORSE-CG coupled n/..gamma.. three-dimensional Monte Carlo code was employed to calculate neutron and gamma doses in a water phantom. Gamma doses calculated in phantom with this code were generally lower than corresponding ion chamber measurements. This can be explained by the departure of irradiation conditions from ideal narrow-beam geometry. 97 references.

Goetsch, S.J.

1983-01-01T23:59:59.000Z

51

Radionuclide neutron sources in calibration laboratory—neutron and gamma doses and their changes in time  

Science Journals Connector (OSTI)

......oxfordjournals.org August 2007 research-article POSTER Presentations Radionuclide neutron sources in calibration...This work was partially supported by the Ministry of Science and Higher Education of Poland; grant No 2P05 D06530. REFERENCES 1 ISO......

K. Józefowicz; N. Golnik; P. Tulik; M. Zielczynski

2007-08-01T23:59:59.000Z

52

Alanine and TLD coupled detectors for fast neutron dose measurements in neutron capture therapy (NCT)  

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......the gamma rays in the reactor is different from that...Sesonske, A. Nuclear Reactor Engineering (Van Nostrand...column of the Tapiro reactor (ENEA-Casaccia RC...hence the precision and reliability of the fast neutron...Design Equipment Failure Analysis Gamma Rays therapeutic......

A. Cecilia; S. Baccaro; A. Cemmi; V. Colli; G. Gambarini; G. Rosi; L. Scolari

2004-08-01T23:59:59.000Z

53

SU?E?T?559: Quality Assurance Utilizing 3D Dose Reconstruction for Stereotactic Lung Body Radiotherapy  

Science Journals Connector (OSTI)

Purpose: Quality assurance for static field stereotactic lung body radiotherapy(SBRT) can present a clinical challenge when using manual calculations film or 2D detector arrays. For both methods verifying the effect of summation from multiple field entry points and patient heterogeneity is extremely difficult if not impossible. To address these concerns reconstructed 3D dose maps from planar measurements were used to evaluate 41 static field lungSBRT plans and compared against the treatment planning system Eclipse. Methods: IBA's Compass software with Matrixx hardware and Sun Nuclear's 3DVH software with MapCheck hardware were used to create 3D dose maps. For the Compass software data used to commission the treatment planning system was used to commission Compass' collapsed cone calculation engine and found to have good agreement for standardized fields in solid water. Plans were then analyzed using both the forward dose calculation engine and backprojected measurements. Results: Compared to Eclipse Compass forward calculated a difference in mean PTV dose for plans ranging from ?0.10 to +4.24%. Compass backprojected measurements showed a difference in mean PTV dose from +0.19 to +5.98% compared to Eclipse and ?3.52 to +3.33% compared to Compass' forward calculation. 3DVH backprojected measurements showed a difference in mean PTV dose from ?4.14 to 1.17% compared to Eclipse. Point measurements using an equivalent path length and field size scaling calculated an average field difference ranging from ? 4.25 to +5.23%. Conclusion: In our dataset point calculations predicted dose to the mean PTV approximately as well as an independent forward calculation using a collapsed cone algorithm backprojection using a sophisticated algorithm and backprojection using dose error perturbation kernels. However 3D reconstructed dose maps indicated drops in target coverage and increase to organs at risk that could be considered clinically relevant.

J Durgin; D Zhang; M Weldon; N Gupta

2011-01-01T23:59:59.000Z

54

Measurement of neutron dose equivalent outside and inside of the treatment vault of GRID therapy  

SciTech Connect

Purpose: To evaluate the neutron and photon dose equivalent rates at the treatment vault entrance (H{sub n,D} and H{sub G}), and to study the secondary radiation to the patient in GRID therapy. The radiation activation on the grid was studied.Methods: A Varian Clinac 23EX accelerator was working at 18 MV mode with a grid manufactured by .decimal, Inc. The H{sub n,D} and H{sub G} were measured using an Andersson–Braun neutron REM meter, and a Geiger Müller counter. The radiation activation on the grid was measured after the irradiation with an ion chamber ?-ray survey meter. The secondary radiation dose equivalent to patient was evaluated by etched track detectors and OSL detectors on a RANDO{sup ®} phantom.Results: Within the measurement uncertainty, there is no significant difference between the H{sub n,D} and H{sub G} with and without a grid. However, the neutron dose equivalent to the patient with the grid is, on average, 35.3% lower than that without the grid when using the same field size and the same amount of monitor unit. The photon dose equivalent to the patient with the grid is, on average, 44.9% lower. The measured average half-life of the radiation activation in the grid is 12.0 (±0.9) min. The activation can be categorized into a fast decay component and a slow decay component with half-lives of 3.4 (±1.6) min and 15.3 (±4.0) min, respectively. There was no detectable radioactive contamination found on the surface of the grid through a wipe test.Conclusions: This work indicates that there is no significant change of the H{sub n,D} and H{sub G} in GRID therapy, compared with a conventional external beam therapy. However, the neutron and scattered photon dose equivalent to the patient decrease dramatically with the grid and can be clinical irrelevant. Meanwhile, the users of a grid should be aware of the possible high dose to the radiation worker from the radiation activation on the surface of the grid. A delay in handling the grid after the beam delivery is suggested.

Wang, Xudong; Charlton, Michael A.; Esquivel, Carlos; Eng, Tony Y.; Li, Ying; Papanikolaou, Nikos [University of Texas Health Science Center, San Antonio, Texas 78229 (United States)] [University of Texas Health Science Center, San Antonio, Texas 78229 (United States)

2013-09-15T23:59:59.000Z

55

SU?E?T?348: Measurement?Guided 4D VMAT Dose Reconstruction on an Arbitrary Homogeneous Dataset  

Science Journals Connector (OSTI)

Purpose: To develop and validate a VMAT QA tool that takes as input a 2D low?density (?10 mm) empirical dose map from a commercial helical diode array and outputs a high density volumetric time?resolved (4D) dose matrix on an arbitrary patient dataset. At first the method validation is limited to a homogeneous ‘patient’. Methods: A VMAT treatment is delivered to a diode array (ArcCHECK Sun Nuclear Corp. Melbourne FL). 3DVH software (Sun Nuclear) derives the high?density volumetric dose using measurement?guided dose reconstruction (MGDR). MGDR cylindrical phantom results are then used to perturb the 3D TPS dose on the patient dataset producing a semi?empirical volumetric dose grid. Four?dimensional dose reconstruction on the patient is also possible by morphing the sub?beam instead of composite dose. For validation TG?119 structures and objectives were used. 3DVH and TPS cumulative point doses were compared to ion chamber in a cube water?equivalent phantom (‘patient’). The shape of the phantom is different from the ArcCHECK and the targets were placed asymmetrically. Ion chamber dose sampled at 10Hz was compared to time?resolved 3DVH point doses. Coronal and sagittal absolute film dose distributions in the cube were compared with 3DVH and TPS. Results: Across four TG?119 plans the average PTV point dose difference in the cube between 3DVH and ion chamber is 0.0±0.9%. Average film vs. 3DVH gamma analysis passing rates are 88.6 96.1 and 99.5% for 1%/2mm 2%/2mm and 3%/3mm criteria respectively. 4D MGDR was also sufficiently accurate. Conclusions: Even for a well?commissioned TPS comparison metrics show on average better agreement between MGDR and measurement compared to MGDR and TPS on the arbitrary?shaped phantom (‘patient’). The method requires no more accelerator time than standard QA while producing more clinically relevant information. Validation in a heterogeneous thoracic phantom is under way as is ultimate application to virtual motion studies. Supported in part by a grant from Sun Nuclear Corp.

D Opp; J Robinson; B Nelms; G Zhang; V Feygelman

2012-01-01T23:59:59.000Z

56

Reconstruction of individual thyroid doses to the Ukrainian subjects enrolled in the Chernobyl Tissue Bank  

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......movements over the radioactively contaminated area, diet composition and amount of foodstuffs being consumed). To reconstruct...IAEA-TECDOC-857. 48 Nosk B. S. , Prister B. S., Loboda M. V. Agrochemical and agroecological state of soils in Ukraine. (1994......

I. Likhtarov; G. Thomas; L. Kovgan; S. Masiuk; M. Chepurny; O. Ivanova; V. Gerasymenko; M. Tronko; T. Bogdanova; A. Bouville

2013-10-01T23:59:59.000Z

57

Three-dimensional heart dose reconstruction to estimate normal tissue complication probability after breast irradiation using portal dosimetry  

SciTech Connect

Irradiation of the heart is one of the major concerns during radiotherapy of breast cancer. Three-dimensional (3D) treatment planning would therefore be useful but cannot always be performed for left-sided breast treatments, because CT data may not be available. However, even if 3D dose calculations are available and an estimate of the normal tissue damage can be made, uncertainties in patient positioning may significantly influence the heart dose during treatment. Therefore, 3D reconstruction of the actual heart dose during breast cancer treatment using electronic imaging portal device (EPID) dosimetry has been investigated. A previously described method to reconstruct the dose in the patient from treatment portal images at the radiological midsurface was used in combination with a simple geometrical model of the irradiated heart volume to enable calculation of dose-volume histograms (DVHs), to independently verify this aspect of the treatment without using 3D data from a planning CT scan. To investigate the accuracy of our method, the DVHs obtained with full 3D treatment planning system (TPS) calculations and those obtained after resampling the TPS dose in the radiological midsurface were compared for fifteen breast cancer patients for whom CT data were available. In addition, EPID dosimetry as well as 3D dose calculations using our TPS, film dosimetry, and ionization chamber measurements were performed in an anthropomorphic phantom. It was found that the dose reconstructed using EPID dosimetry and the dose calculated with the TPS agreed within 1.5% in the lung/heart region. The dose-volume histograms obtained with EPID dosimetry were used to estimate the normal tissue complication probability (NTCP) for late excess cardiac mortality. Although the accuracy of these NTCP calculations might be limited due to the uncertainty in the NTCP model, in combination with our portal dosimetry approach it allows incorporation of the actual heart dose. For the anthropomorphic phantom, and for fifteen patients for whom CT data were available to test our method, the average difference between the NTCP values obtained with our method and those resulting from the dose distributions calculated with the TPS was 0.1% {+-}0.3% (1 SD). Most NTCP values were 1%-2% lower than those obtained using the method described by Hurkmans et al. [Radiother. Oncol. 62, 163-171 (2002)], using the maximum heart distance determined from a simulator image as a single pre-treatment parameter. A similar difference between the two methods was found for twelve patients using in vivo EPID dosimetry; the average NTCP value obtained with EPID dosimetry was 0.9%, whereas an average NTCP value of 2.2% was derived using the method of Hurkmans et al. The results obtained in this study show that EPID dosimetry is well suited for in vivo verification of the heart dose during breast cancer treatment, and can be used to estimate the NTCP for late excess cardiac mortality. To the best of our knowledge, this is the first study using portal dosimetry to calculate a DVH and NTCP of an organ at risk.

Louwe, R. J. W.; Wendling, M.; Herk, M. B. van; Mijnheer, B. J. [Department of Radiation Oncology, Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands)

2007-04-15T23:59:59.000Z

58

Assessment of dedicated low-dose cardiac micro-CT reconstruction algorithms using the left ventricular volume of small rodents as a performance measure  

SciTech Connect

Purpose: Phase-correlated microcomputed tomography (micro-CT) imaging plays an important role in the assessment of mouse models of cardiovascular diseases and the determination of functional parameters as the left ventricular volume. As the current gold standard, the phase-correlated Feldkamp reconstruction (PCF), shows poor performance in case of low dose scans, more sophisticated reconstruction algorithms have been proposed to enable low-dose imaging. In this study, the authors focus on the McKinnon-Bates (MKB) algorithm, the low dose phase-correlated (LDPC) reconstruction, and the high-dimensional total variation minimization reconstruction (HDTV) and investigate their potential to accurately determine the left ventricular volume at different dose levels from 50 to 500 mGy. The results were verified in phantom studies of a five-dimensional (5D) mathematical mouse phantom. Methods: Micro-CT data of eight mice, each administered with an x-ray dose of 500 mGy, were acquired, retrospectively gated for cardiac and respiratory motion and reconstructed using PCF, MKB, LDPC, and HDTV. Dose levels down to 50 mGy were simulated by using only a fraction of the projections. Contrast-to-noise ratio (CNR) was evaluated as a measure of image quality. Left ventricular volume was determined using different segmentation algorithms (Otsu, level sets, region growing). Forward projections of the 5D mouse phantom were performed to simulate a micro-CT scan. The simulated data were processed the same way as the real mouse data sets. Results: Compared to the conventional PCF reconstruction, the MKB, LDPC, and HDTV algorithm yield images of increased quality in terms of CNR. While the MKB reconstruction only provides small improvements, a significant increase of the CNR is observed in LDPC and HDTV reconstructions. The phantom studies demonstrate that left ventricular volumes can be determined accurately at 500 mGy. For lower dose levels which were simulated for real mouse data sets, the HDTV algorithm shows the best performance. At 50 mGy, the deviation from the reference obtained at 500 mGy were less than 4%. Also the LDPC algorithm provides reasonable results with deviation less than 10% at 50 mGy while PCF and MKB reconstruction show larger deviations even at higher dose levels. Conclusions: LDPC and HDTV increase CNR and allow for quantitative evaluations even at dose levels as low as 50 mGy. The left ventricular volumes exemplarily illustrate that cardiac parameters can be accurately estimated at lowest dose levels if sophisticated algorithms are used. This allows to reduce dose by a factor of 10 compared to today's gold standard and opens new options for longitudinal studies of the heart.

Maier, Joscha, E-mail: joscha.maier@dkfz.de [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)] [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Sawall, Stefan; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen (Germany)] [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen (Germany)

2014-05-15T23:59:59.000Z

59

Selected Hanford reactor and separations operating data for 1960--1964. Hanford Environmental Dose Reconstruction Project  

SciTech Connect

The purpose of this letter report is to reconstruct from available information that data which can be used to develop daily reactor operating history for 1960--1964. The information needed for source team calculations (as determined by the Source Terms Task Leader) were extracted and included in this report. The data on the amount of uranium dissolved by the separations plants (expressed both as tons and as MW) is also included in this compilation.

Gydesen, S.P.

1992-09-01T23:59:59.000Z

60

Measurements of gamma dose and thermal neutron fluence in phantoms exposed to a BNCT epithermal beam with TLD-700  

Science Journals Connector (OSTI)

......parameters utilised for the analysis of TLD-700 chips...after exposure (a) at reactor and (b) at the 60Co...beam of the LVR-15 reactor, dedicated to BNCT...Pirola L. Study of reliability of TLFs for the photon dose mapping in reactor neutron fields for BNCT......

G. Gambarini; D. Magni; V. Regazzoni; M. Borroni; M. Carrara; E. Pignoli; J. Burian; M. Marek; V. Klupak; L. Viererbl

2014-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

SAVANNAH RIVER SITE (SRS) Phase II of the SRS Dose Reconstruction Project  

E-Print Network (OSTI)

, and Augusta, Georgia. Beginning in 1953, the Du Pont Company produced plutonium and tritium at the Savannah radioactive materials and chemicals, to air and water. Some people living near the SRS during these past and support, waste management and environmental remediation facilities are still operating.) THE SRS DOSE

62

Letter report: Population estimates by age, sex and race for 10-county study area. Hanford Environmental Dose Reconstruction Project  

SciTech Connect

The Hanford Environmental Does Reconstruction (HEDR) Project was established to estimate radiation doses that people could have received from nuclear operations at the Hanford Site since 1944. To identify groups that may have received doses, population estimates containing age, race, and sex detail for ten counties in Washington and Oregon for the years 1940 to 1980 were prepared by the Demographics Laboratory under a subcontract with the Pacific Northwest Laboratory (PNL). A data base of population information was developed from census reports and published and unpublished collections from the Washington State Office of Financial Management and Center for Population Research. Three estimation methods were then explored: the cohort-component model, cohort interpolation, and age-group interpolation. The estimates generated through cohort and age-group interpolation are considered adequate for initial use in the HEDR Project. Results are presented in two forms: (1) county populations by sex and single year of age and (2) county populations by sex and race for age groupings. These results are made available to the HEDR Project for further refinement into population estimates by county census divisions.

Pittenger, D.B.

1992-02-01T23:59:59.000Z

63

Literature and data review for the surface-water pathway: Columbia River and adjacent coastal areas. Hanford Environmental Dose Reconstruction Project  

SciTech Connect

As part of the Hanford Environmental Dose Reconstruction Project, Pacific Northwest Laboratory reviewed literature and data on radionuclide concentrations and distribution in the water, sediment, and biota of the Columbia River and adjacent coastal areas. Over 600 documents were reviewed including Hanford reports, reports by offsite agencies, journal articles, and graduate theses. Certain radionuclide concentration data were used in preliminary estimates of individual dose for the 1964--1966 time period. This report summarizes the literature and database review and the results of the preliminary dose estimates.

Walters, W.H.; Dirkes, R.L.; Napier, B.A.

1992-04-01T23:59:59.000Z

64

Assessment of individual organ doses in a realistic human phantom from neutron and gamma stimulated spectroscopy of the breast and liver  

SciTech Connect

Purpose: Understanding the radiation dose to a patient is essential when considering the use of an ionizing diagnostic imaging test for clinical diagnosis and screening. Using Monte Carlo simulations, the authors estimated the three-dimensional organ-dose distribution from neutron and gamma irradiation of the male liver, female liver, and female breasts for neutron- and gamma-stimulated spectroscopic imaging. Methods: Monte Carlo simulations were developed using the Geant4 GATE application and a voxelized XCAT human phantom. A male and a female whole body XCAT phantom was voxelized into 256 × 256 × 600 voxels (3.125 × 3.125 × 3.125 mm{sup 3}). A monoenergetic rectangular beam of 5.0 MeV neutrons or 7.0 MeV photons was made incident on a 2 cm thick slice of the phantom. The beam was rotated at eight different angles around the phantom ranging from 0° to 180°. Absorbed dose was calculated for each individual organ in the body and dose volume histograms were computed to analyze the absolute and relative doses in each organ. Results: The neutron irradiations of the liver showed the highest organ dose absorption in the liver, with appreciably lower doses in other proximal organs. The dose distribution within the irradiated slice exhibited substantial attenuation with increasing depth along the beam path, attenuating to ?15% of the maximum value at the beam exit side. The gamma irradiation of the liver imparted the highest organ dose to the stomach wall. The dose distribution from the gammas showed a region of dose buildup at the beam entrance, followed by a relatively uniform dose distribution to all of the deep tissue structures, attenuating to ?75% of the maximum value at the beam exit side. For the breast scans, both the neutron and gamma irradiation registered maximum organ doses in the breasts, with all other organs receiving less than 1% of the breast dose. Effective doses ranged from 0.22 to 0.37 mSv for the neutron scans and 41 to 66 mSv for the gamma scans. Conclusions: Neutron and gamma irradiation of a primary target organ was found to impart the majority of the total dose to the primary target organ (and other large organs) within the beam plane and considerably lower dose to proximal organs outside of the beam. These results also indicate that despite the use of a highly scattering particle such as a neutron, the dose from neutron stimulated emission computed tomography scans is on par with other clinical imaging techniques such as x-ray computed tomography (x-ray CT). Given the high nonuniformity in the dose across an organ during the neutron scan, care must be taken when computing average doses from neutron irradiations. The effective doses from neutron scanning were found to be comparable to x-ray CT. Further technique modifications are needed to reduce the effective dose levels from the gamma scans.

Belley, Matthew D. [Medical Physics Graduate Program, Duke University, Durham 27705, North Carolina (United States)] [Medical Physics Graduate Program, Duke University, Durham 27705, North Carolina (United States); Segars, William Paul; Kapadia, Anuj J., E-mail: anuj.kapadia@duke.edu [Medical Physics Graduate Program, Duke University, Durham, North Carolina and Department of Radiology, Carl E. Ravin Advanced Imaging Laboratories, Duke University Medical Center, Durham 27710, North Carolina (United States)

2014-06-15T23:59:59.000Z

65

Estimation of the contribution of photon radiation for measurement of the exposure dose rate of neutron sources based on 252Cf  

Science Journals Connector (OSTI)

A method for the estimation of the contribution of photon radiation to the detector readings for measurement of the exposure dose rate and the equivalent activity of neutron ... screens and filters is considered....

N. F. Demchenko; R. N. Minvaliev; V. I. Shipilov…

2012-06-01T23:59:59.000Z

66

Estimation of neutron-equivalent dose in organs of patients undergoing radiotherapy by the use of a novel online digital detector  

Science Journals Connector (OSTI)

Neutron peripheral contamination in patients undergoing high-energy photon radiotherapy is considered as a risk factor for secondary cancer induction. Organ-specific neutron-equivalent dose estimation is therefore essential for a reasonable assessment of these associated risks. This work aimed to develop a method to estimate neutron-equivalent doses in multiple organs of radiotherapy patients. The method involved the convolution, at 16 reference points in an anthropomorphic phantom, of the normalized Monte Carlo neutron fluence energy spectra with the kerma and energy-dependent radiation weighting factor. This was then scaled with the total neutron fluence measured with passive detectors, at the same reference points, in order to obtain the equivalent doses in organs. The latter were correlated with the readings of a neutron digital detector located inside the treatment room during phantom irradiation. This digital detector, designed and developed by our group, integrates the thermal neutron fluence. The correlation model, applied to the digital detector readings during patient irradiation, enables the online estimation of neutron-equivalent doses in organs. The model takes into account the specific irradiation site, the field parameters (energy, field size, angle incidence, etc) and the installation (linac and bunker geometry). This method, which is suitable for routine clinical use, will help to systematically generate the dosimetric data essential for the improvement of current risk-estimation models.

F Sánchez-Doblado; C Domingo; F Gómez; B Sánchez-Nieto; J L Muñiz; M J García-Fusté; M R Expósito; R Barquero; G Hartmann; J A Terrón; J Pena; R Méndez; F Gutiérrez; F X Guerre; J Roselló; L Núñez; L Brualla-González; F Manchado; A Lorente; E Gallego; R Capote; D Planes; J I Lagares; X González-Soto; F Sansaloni; R Colmenares; K Amgarou; E Morales; R Bedogni; J P Cano; F Fernández

2012-01-01T23:59:59.000Z

67

Feasibility of boron neutron capture therapy (BNCT) for malignant pleural mesothelioma from a viewpoint of dose distribution analysis  

SciTech Connect

Purpose: To investigate the feasibility of boron neutron capture therapy (BNCT) for malignant pleural mesothelioma (MPM) from a viewpoint of dose distribution analysis using Simulation Environment for Radiotherapy Applications (SERA), a currently available BNCT treatment planning system. Methods and Materials: The BNCT treatment plans were constructed for 3 patients with MPM using the SERA system, with 2 opposed anterior-posterior beams. The {sup 1}B concentrations in the tumor and normal lung in this study were assumed to be 84 and 24 ppm, respectively, and were derived from data observed in clinical trials. The maximum, mean, and minimum doses to the tumors and the normal lung were assessed for each plan. The doses delivered to 5% and 95% of the tumor volume, D{sub 05} and D{sub 95}, were adopted as the representative dose for the maximum and minimum dose, respectively. Results: When the D{sub 05} to the normal ipsilateral lung was 5 Gy-Eq, the D{sub 95} and mean doses delivered to the normal lung were 2.2-3.6 and 3.5-4.2 Gy-Eq, respectively. The mean doses delivered to the tumors were 22.4-27.2 Gy-Eq. The D{sub 05} and D{sub 95} doses to the tumors were 9.6-15.0 and 31.5-39.5 Gy-Eq, respectively. Conclusions: From a viewpoint of the dose-distribution analysis, BNCT has the possibility to be a promising treatment for MPM patients who are inoperable because of age and other medical illnesses.

Suzuki, Minoru [Particle Oncology Research Center, Osaka (Japan)]. E-mail: msuzuki@rri.kyoto-u.ac.jp; Sakurai, Yoshinori [Division of Medical Physics, Department of Radiation Life Science, Research Reactor Institute, Kyoto University, Osaka (Japan); Masunaga, Shinichiro [Particle Oncology Research Center, Osaka (Japan); Kinashi, Yuko [Particle Oncology Research Center, Osaka (Japan); Nagata, Kenji [Particle Oncology Research Center, Osaka (Japan); Maruhashi, Akira [Division of Medical Physics, Department of Radiation Life Science, Research Reactor Institute, Kyoto University, Osaka (Japan); Ono, Koji [Particle Oncology Research Center, Osaka (Japan)

2006-12-01T23:59:59.000Z

68

Use of international data sets to evaluate and validate pathway assessment models applicable to exposure and dose reconstruction at DOE facilities. Progress report, August 1993--January 1994  

SciTech Connect

This project, ``Use of International Data Sets to Evaluate and Validate Pathway Assessment Models Applicable to Exposure and Dose Reconstruction at DOE Facilities,`` grew out of several activities being conducted by the Principal Investigator Dr. F Owen Hoffman. One activity was originally part of the Chernobyl Studies Project and began as Task 7.1D, ``Internal Dose From Direct Contamination of Terrestrial Food Sources.`` The objective of Task 7.1D was to (1) establish a collaborative US USSR effort to improve and validate our methods of forecasting doses and dose commitments from the direct contamination of food sources, and (2) perform experiments and validation studies to improve our ability to predict rapidly and accurately the long-term internal dose from the contamination of agricultural soil. The latter was to include the consideration of remedial measures to block contamination of food grown on contaminated soil. The current objective of this project is to evaluate and validate pathway-assessment models applicable to exposure and dose reconstruction at DOE facilities through use of international data sets. This project incorporates the activity of Task 7.1D into a multinational effort to evaluate data used for the prediction of radionuclide transfer through agricultural and aquatic systems to humans. It also includes participation in two multinational studies, BIOMOVS (BIOspheric MOdel Validation Study) with the Swedish National Institute for Radiation Protection and VAMP (VAlidation of Model Predictions) with the International Atomic Energy Agency, that address testing the performance of models of radionuclide transport through foodchains.

Hendrickson, S.M. [ed.] [Lawrence Livermore National Lab., CA (United States)] [ed.; Lawrence Livermore National Lab., CA (United States); Hoffman, F.O. [Senes Oak Ridge, Inc., TN (United States). Center for Risk Analysis] [Senes Oak Ridge, Inc., TN (United States). Center for Risk Analysis

1994-03-01T23:59:59.000Z

69

Development of microstructure and irradiation hardening of Zircaloy during low dose neutron irradiation at nominally 358 C  

SciTech Connect

Wrought Zircaloy-2 and Zircaloy-4 were neutron irradiated at nominally 358 C in the high flux isotope reactor (HFIR) at relatively low neutron fluences between 5.8 1022 and 2.9 1025 n/m2 (E > 1 MeV). The irradiation hardening and change in microstructure were characterized following irradiation using tensile testing and examinations of microstructure using Analytical Electron Microscopy (AEM). Small increments of dose (0.0058, 0.11, 0.55, 1.08, and 2.93 1025 n/m2) were used in the range where the saturation of irradiation hardening is typically observed so that the role of microstructure evolution and hai loop formation on irradiation hardening could be correlated. An incubation dose between 5.8 1023 and 1.1 1024 n/m2 was needed for loop nucleation to occur that resulted in irradiation hardening. Increases in yield strength were consistent with previous results in this temperature regime, and as expected less irradiation hardening and lower hai loop number density values than those generally reported in literature for irradiations at 260 326 C were observed. Unlike previous lower temperature data, there is evidence in this study that the irradiation hardening can decrease with dose over certain ranges of fluence. Irradiation induced voids were observed in very low numbers in the Zircaloy-2 materials at the highest fluence.

Cockeram, Brian V [Bechtel-Bettis, Inc.; Smith, Richard W [Bechtel-Bettis, Inc.; Leonard, Keith J [ORNL; Byun, Thak Sang [ORNL; Snead, Lance Lewis [ORNL

2011-01-01T23:59:59.000Z

70

Evaluation of the neutron spectrum and dose assessment around the venus reactor  

Science Journals Connector (OSTI)

......concrete wall. Figure 1. MCNPX geometry input front view y 0 (left) and top view...measurement places are represented in the MCNPX input file (Figure 1). A first series of...Statistical Monte Carlo Method Neutrons Nuclear Fusion Nuclear Reactors Radiation Dosage Radiation......

Michèle Coeck; Fernand Vermeersch; Filip Vanhavere

2005-12-20T23:59:59.000Z

71

WHOLE-BODY DOSE EVALUATION WITH AN ADAPTIVE TREATMENT PLANNING SYSTEM FOR BORON NEUTRON CAPTURE THERAPY  

Science Journals Connector (OSTI)

......thoracoabdominal organ dose during BNCT for a brain tumour and maxillary sinus tumour was 50-360...for various organs during BNCT BNCT for a brain tumour The authors evaluated the undesirable...various organs during BNCT irradiation of a brain tumour, using a whole-body phantom......

Kenta Takada; Hiroaki Kumada; Tomonori Isobe; Toshiyuki Terunuma; Satoshi Kamizawa; Hideyuki Sakurai; Takeji Sakae; Akira Matsumura

2014-12-01T23:59:59.000Z

72

A comparison of neutron dose measurement techniques at the K500 Superconducting Cyclotron facility  

E-Print Network (OSTI)

encountered in accelerator environments. On the forefront, previous work at the Health Physics Research Reactor (HPRR) at Oak Ridge National Laboratory (ORNL) has focused on intercomparisons of dosimeter response in a reactor environment (Swaja et al. 1985..., theoretically, the differential TLD method (using the Li and Li chips') allows for measurements of 0. 1 mSv of neutrons in a gamma field of 2 mSv. The ORNL study cited in the introduction revealed that the TLD albedo dosimeters provided the best overall...

Ford, Michael Scott

1989-01-01T23:59:59.000Z

73

DQS Advisor: A visual interface and knowledge-based system to balance dose, quality, and reconstruction speed in iterative  

E-Print Network (OSTI)

the limited projection data collected at reduced X-ray radiation is challenging, and iterative algorithms have concerns with regards to the X-ray dose delivered to the patient, low-dose Computed Tomography (CT) has and K Mueller Visual Analytic and Imaging Lab, Computer Science Department, Stony Brook University, NY

Mueller, Klaus

74

Dose point kernel for boron-11 decay and the cellular S values in boron neutron capture therapy  

Science Journals Connector (OSTI)

The study of the radiobiology of boronneutron capture therapy is based on the cellular level dosimetry of boron-10’s thermal neutron capture reaction B 10 ( n ? ) Li 7 in which one 1.47 MeV helium-4 ion and one 0.84 MeV lithium-7 ion are spawned. Because of the chemical preference of boron-10 carrier molecules the dose is heterogeneously distributed in cells. In the present work the (scaled) dose point kernel of boron-11 decay called B 11 -DPK was calculated by GEANT4Monte Carlo simulation code. The DPK curve drops suddenly at the radius of 4.26 ? m the continuous slowing down approximation (CSDA) range of a lithium-7 ion. Then after a slight ascending the curve decreases to near zero when the radius goes beyond 8.20 ? m which is the CSDA range of a 1.47 MeV helium-4 ion. With the DPK data S values for nuclei and cells with the boron-10 on the cell surface are calculated for different combinations of cell and nucleus sizes. The S value for a cell radius of 10 ? m and a nucleus radius of 5 ? m is slightly larger than the value published by Tung et al. [Appl. Radiat. Isot.61 739–743 (2004)]. This result is potentially more accurate than the published value since it includes the contribution of a lithium-7 ion as well as the alpha particle.

Yunzhi Ma; JinPeng Geng; Song Gao; Shanglian Bao

2006-01-01T23:59:59.000Z

75

Calculation of extremity neutron fluence-to-dose equivalent conversion factors  

E-Print Network (OSTI)

) Figure 4. Comparison of NCRP 38 and Siebert and Schuhmacher quality factors. Table 2. PNNL dose equivalent averaged quality factors (Q). * Phantom Finger Wrist 30 cm ICRU sphere Composition PMMA PMMA Tissue-and-bone Tissue-and-bone PMMA PMMA... Tissue-and-bone Tissue-and-bone PM MA PMMA (???) 'Adapted from reference 53. Source Bare Cf Moderated Cf Bare Cf Moderated Cf Bare Cf Moderated Cf Bare Cf Moderated Cf Bare Cf Moderated Cf 9. 2 9. 7 9. 2 9. 7 9. 4 9. 7 9. 4 9. 7 10...

Wood-Zika, Annmarie Ruth

1997-01-01T23:59:59.000Z

76

Determination of Radionuclides Induced by Fast Neutrons from the JCO Criticality Accident in Tokai-mura, Japan for Estimating Neutron Doses  

Science Journals Connector (OSTI)

......the g-ray spectrum of the mesh...sections14) with fission neutrons or thermal neutrons...threshold energies for all of...60 Co were induced by (n...Non-destructive -ray spectrum for the mesh...thresh- old energy of the 60...half-lives of neutron-induced radionuclides...abundance) / MeV Fission/ m barn Thermal/ barn......

Sadao Kojima; Tetsuji Imanaka; Jitsuya Takada; Toshiaki Mitsugashira; Takashi Nakanishi; Riki Seki; Muneharu Kondo; Ken-Ichi Sasaki; Tadashi Saito; Yoshiaki Yamaguchi; Michiaki Furukawa

2001-09-01T23:59:59.000Z

77

Dose reconstruction for an occupational cohort at the Savannah River nuclear facility: evaluation of a hybrid method  

Science Journals Connector (OSTI)

......tritium dose estimation methods, including International...workers at a nuclear fuels production facility. Am. J...evaluation of a hybrid method. | The Savannah River...radioactive isotope of hydrogen. The purpose of the...matrix. The proposed method is unique in that along......

Ghassan Hamra; Leena A. Nylander-French; David Richardson

2008-08-01T23:59:59.000Z

78

Dose reconstruction for an occupational cohort at the Savannah River nuclear facility: evaluation of a hybrid method  

Science Journals Connector (OSTI)

......reprocessing of reactor fuels(19). However...type and number of reactors operating at SRS...dose. Statistical analysis The proportion of...her coworker. The reliability of this estimation...Statistical Nuclear Reactors statistics & numerical...methods Tritium analysis United States...

Ghassan Hamra; Leena A. Nylander-French; David Richardson

2008-08-01T23:59:59.000Z

79

Reconstructing the neutron-star equation of state with gravitational-wave detectors from a realistic population of inspiralling binary neutron stars  

E-Print Network (OSTI)

Gravitational-wave observations of inspiralling binary neutron star systems can be used to measure the neutron-star equation of state (EOS) through the tidally induced shift in the waveform phase that depends on the tidal deformability parameter $\\lambda$. Previous work has shown that $\\lambda$, a function of the neutron-star EOS and mass, is measurable by Advanced LIGO for a single event when including tidal information up to the merger frequency. In this work, we describe a method for stacking measurements of $\\lambda$ from multiple inspiral events to measure the EOS. We use Markov chain Monte Carlo simulations to estimate the parameters of a 4-parameter piecewise polytrope EOS that matches theoretical EOS models to a few percent. We find that, for "realistic" event rates ($\\sim 40$ binary neutron star inspiral events per year with signal-to-noise ratio $> 8$ in a single Advanced LIGO detector), combining a year of gravitational-wave data from a three-detector network with the constraints from causality and recent high mass neutron-star measurements, the EOS above nuclear density can be measured to better than a factor of two in pressure in most cases. We also find that in the mass range $1M_\\odot$--$2M_\\odot$, the neutron-star radius can be measured to better than $\\pm 1$ km and the tidal deformability can be measured to better than $\\pm 1 \\times 10^{36}$ g cm$^2$ s$^2$ (10%--50% depending on the EOS and mass). The overwhelming majority of this information comes from the loudest $\\sim 5$ events. Current uncertainties in the post-Newtonian waveform model, however, lead to systematic errors in the EOS measurement that are as large as the statistical errors, and more accurate waveform models are needed to minimize this error.

Benjamin D. Lackey; Leslie Wade

2014-10-31T23:59:59.000Z

80

Direction distribution of ambient neutron dose equivalent from 20 MeV protons incident on thick Be and Cu targets  

Science Journals Connector (OSTI)

......takes into account neutrons of energy greater than about...instrument responds down to thermal energy. The deviation of...distribution such as a fission neutron spectrum. Figure 3. The neutron...section from proton-induced reactions on Cu and......

C. Sunil; A. A. Shanbhag; M. Nandy; M. Maiti; T. Bandyopadhyay; P. K. Sarkar

2009-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
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81

A semi-experimental nodal synthesis method for the on-line reconstruction of three-dimensional neutron flux-shapes and reactivity  

SciTech Connect

The safety and optimal performance of large, commercial, light-water reactors require the knowledge at all time of the neutron-flux distribution in the core. In principle, this information can be obtained by solving the time-dependent neutron diffusion equations. However, this approach is complicated and very expensive. Sufficiently accurate, real-time calculations (time scale of approximately one second) are not yet possible on desktop computers, even with fast-running, nodal kinetics codes. A semi-experimental, nodal synthesis method which avoids the solution of the time-dependent, neutron diffusion equations is described. The essential idea of this method is to approximate instantaneous nodal group-fluxes by a linear combination of K, precomputed, three-dimensional, static expansion-functions. The time-dependent coefficients of the combination are found from the requirement that the reconstructed flux-distribution agree in a least-squares sense with the readings of J ({ge}K) fixed, prompt-responding neutron-detectors. Possible numerical difficulties with the least-squares solution of the ill-conditioned, J-by-K system of equations are brought under complete control by the use of a singular-value-decomposition technique. This procedure amounts to the rearrangement of the original, linear combination of K expansion functions into an equivalent more convenient, linear combination of R ({le}K) orthogonalized modes'' of decreasing magnitude. Exceedingly small modes are zeroed to eliminate any risk of roundoff-error amplification, and to assure consistency with the limited accuracy of the data. Additional modes are zeroed when it is desirable to limit the sensitivity of the results to measurement noise.

Jacqmin, R.P.

1991-12-10T23:59:59.000Z

82

A semi-experimental nodal synthesis method for the on-line reconstruction of three-dimensional neutron flux-shapes and reactivity. Final report  

SciTech Connect

The safety and optimal performance of large, commercial, light-water reactors require the knowledge at all time of the neutron-flux distribution in the core. In principle, this information can be obtained by solving the time-dependent neutron diffusion equations. However, this approach is complicated and very expensive. Sufficiently accurate, real-time calculations (time scale of approximately one second) are not yet possible on desktop computers, even with fast-running, nodal kinetics codes. A semi-experimental, nodal synthesis method which avoids the solution of the time-dependent, neutron diffusion equations is described. The essential idea of this method is to approximate instantaneous nodal group-fluxes by a linear combination of K, precomputed, three-dimensional, static expansion-functions. The time-dependent coefficients of the combination are found from the requirement that the reconstructed flux-distribution agree in a least-squares sense with the readings of J ({ge}K) fixed, prompt-responding neutron-detectors. Possible numerical difficulties with the least-squares solution of the ill-conditioned, J-by-K system of equations are brought under complete control by the use of a singular-value-decomposition technique. This procedure amounts to the rearrangement of the original, linear combination of K expansion functions into an equivalent more convenient, linear combination of R ({le}K) orthogonalized ``modes`` of decreasing magnitude. Exceedingly small modes are zeroed to eliminate any risk of roundoff-error amplification, and to assure consistency with the limited accuracy of the data. Additional modes are zeroed when it is desirable to limit the sensitivity of the results to measurement noise.

Jacqmin, R.P.

1991-12-10T23:59:59.000Z

83

Letter report: References for radioactive releases to the atmosphere from Hanford operations, 1944--1957. Hanford Environmental Dose Reconstruction Project  

SciTech Connect

A search was made for published documents related to discharges of radioactive material from Hanford Site facilities to the atmosphere from 1944--1957. The purpose was to list documents that contain data that might be useful in developing a source term for airborne releases. The source term for the radionuclide that contributes most to dose, ioidine-131, is a separate effort. Other source terms will be developed later. This tabulation of published summaries of atmospheric release data shows the type of measurements that were being made from 1944--1957 and the magnitude of the discharges to the atmosphere. In the early years, very little data were collected that related to specific radionuclides. However, most of the key radionuclides were known to be present in effluents from occasional specific radionuclide analyses. 2 refs.

Hall, R.B.

1991-11-01T23:59:59.000Z

84

Measurement of neutron spectra for determining dose equivalent rates at the Texas A&M University Nuclear Science Center  

E-Print Network (OSTI)

. Also, placement of the detector in a low flux neutron environment adjacent to the area to be characterized could be utilized. These recommendations are reasonable for measurements taken at commercial power plants in areas where personnel exposure... reactions in this region, He 3 10 proportional counters have been proposed by Brackenbush (Br84) to measure neutron spectra up to 1 MeV. The He detector is surrounded by a thermal neutron absorber to maximize the sensitivity at the low end...

Sanza, Bruce Jerome

2012-06-07T23:59:59.000Z

85

Relation Between Tolerance Dose of Skin and Boron-10 Concentration in Neutron Capture Therapy for Cutaneous Melanoma  

Science Journals Connector (OSTI)

In boron neutron capture therapy of cutaneous melanoma1, damage to scalp, facial skin and eyes must be strictly avoided. Two basic irradiation conditions follow: (1) ...

Tooru Kobayashi; Keiji Kanda; Yowri Ujeno…

1992-01-01T23:59:59.000Z

86

Boron neutron capture therapy (BNCT) for liver metastasis in an experimental model: dose–response at five-week follow-up based on retrospective dose assessment in individual rats  

SciTech Connect

Boron neutron capture therapy (BNCT) was proposed for untreatable colorectal liver metastases. Employing an experimental model of liver metastases in rats, we recently demonstrated that BNCT mediated by boronophenylalanine (BPA-BNCT) at 13 Gy prescribed to tumor is therapeutically useful at 3-week follow-up. The aim of the present study was to evaluate dose–response at 5-week follow-up, based on retrospective dose assessment in individual rats. BDIX rats were inoculated with syngeneic colon cancer cells DHD/K12/TRb. Tumor-bearing animals were divided into three groups: BPA-BNCT (n = 19), Beam only (n = 8) and Sham (n = 7) (matched manipulation, no treatment). For each rat, neutron flux was measured in situ and boron content was measured in a pre-irradiation blood sample for retrospective individual dose assessment. For statistical analysis (ANOVA), individual data for the BPA-BNCT group were pooled according to absorbed tumor dose, BPA-BNCT I: 4.5–8.9 Gy and BPA-BNCT II: 9.2–16 Gy. At 5 weeks post-irradiation, the tumor surface area post-treatment/pre-treatment ratio was 12.2 +/- 6.6 for Sham, 7.8 +/- 4.1 for Beam only, 4.4 +/- 5.6 for BPA-BNCT I and 0.45 +/- 0.20 for BPA-BNCT II; tumor nodule weight was 750 +/- 480 mg for Sham, 960 +/- 620 mg for Beam only, 380 +/- 720 mg for BPA-BNCT I and 7.3 +/- 5.9 mg for BPA-BNCT II. The BPA-BNCT II group exhibited statistically significant tumor control with no contributory liver toxicity. Potential threshold doses for tumor response and significant tumor control were established at 6.1 and 9.2 Gy, respectively.

Emiliano C. C. Pozzi; Veronica A. Trivilin; Lucas L. Colombo; Andrea Monti Hughes; Silvia I. Thorp; Jorge E. Cardoso; Marcel A. Garabalino; Ana J. Molinari; Elisa M. Heber; Paula Curotto; Marcelo Miller; Maria E. Itoiz; Romina F. Aromando; David W. Nigg; Amanda E. Schwint

2013-11-01T23:59:59.000Z

87

Dose reconstruction for the Urals population. Joint Coordinating Committee on Radiation Effects Research, Project 1.1 -- Final report  

SciTech Connect

This work is being carried out as a feasibility study to determine if a long-term course of work can be implemented to assess the long-term risks of radiation exposure delivered at low to moderate dose rates to the populations living in the vicinity of the Mayak Industrial Association (MIA). This work was authorized and conducted under the auspices of the US-Russian Joint Coordinating Committee on Radiation Effects Research (JCCRER) and its Executive Committee (EC). The MIA was the first Russian site for the production and separation of plutonium. This plant began operation in 1948, and during its early days there were technological failures that resulted in the release of large amounts of waste into the rather small Techa River. There were also gaseous releases of radioiodines and other radionuclides during the early days of operation. In addition, there was an accidental explosion in a waste storage tank in 1957 that resulted in a significant release. The Techa River Cohort has been studied for several years by scientists from the Urals Research Centre for Radiation Medicine and an increase in both leukemia and solid tumors has been noted.

Degteva, M.O. [Urals Research Center for Radiation Medicine, Chelyabinsk (Russian Federation)] [Urals Research Center for Radiation Medicine, Chelyabinsk (Russian Federation); Drozhko, E. [Branch 1 of Moscow Biophysics Inst., Ozersk (Russian Federation)] [Branch 1 of Moscow Biophysics Inst., Ozersk (Russian Federation); Anspaugh, L.R. [Lawrence Livermore National Lab., CA (United States)] [Lawrence Livermore National Lab., CA (United States); Napier, B.A. [Pacific Northwest National Lab., Richland, WA (United States)] [Pacific Northwest National Lab., Richland, WA (United States); Bouville, A.C. [National Cancer Inst., Bethesda, MD (United States)] [National Cancer Inst., Bethesda, MD (United States); Miller, C.W. [Centers for Disease Control and Prevention, Atlanta, GA (United States)] [Centers for Disease Control and Prevention, Atlanta, GA (United States)

1996-02-01T23:59:59.000Z

88

Dose and Dose-rate Effects of X rays and Fission Neutrons on Lymphocyte Apoptosis in p53(+/+) and p53(-/-) Mice  

Science Journals Connector (OSTI)

......p53 accumulation was not observed in similarly treated ATM-defective (AT) fibroblasts; moreover, when AT fibroblasts were treated...low-level radiation, i.e., mutagenesis, teratogenesis and car- cinogenesis, are dose-rate dependent events. All of the......

Kazuo Fujikawa; Yukinori Hasegawa; Shinya Matsuzawa; Akihiro Fukunaga; Tetsuo Itoh; Sohei Kondo

2000-06-01T23:59:59.000Z

89

Measurement of cosmic-ray neutron dose onboard a polar route flight from New York to Seoul  

Science Journals Connector (OSTI)

......neutrons with the energies 15 MeV. The...departed from New York/John F. Kennedy...flight from New York to Seoul; the...broad range of energy from thermal...D. High-energy response of...flight from New York to Seoul......

Hiroshi Yasuda; Jaejin Lee; Kazuaki Yajima; Jung A. Hwang; Kazuo Sakai

2011-07-01T23:59:59.000Z

90

Impact of intra-arterial administration of boron compounds on dose-volume histograms in boron neutron capture therapy for recurrent head-and-neck tumors  

SciTech Connect

Purpose: To analyze the dose-volume histogram (DVH) of head-and-neck tumors treated with boron neutron capture therapy (BNCT) and to determine the advantage of the intra-arterial (IA) route over the intravenous (IV) route as a drug delivery system for BNCT. Methods and Materials: Fifteen BNCTs for 12 patients with recurrent head-and-neck tumors were included in the present study. Eight irradiations were done after IV administration of boronophenylalanine and seven after IA administration. The maximal, mean, and minimal doses given to the gross tumor volume were assessed using a BNCT planning system. Results: The results are reported as median values with the interquartile range. In the IA group, the maximal, mean, and minimal dose given to the gross tumor volume was 68.7 Gy-Eq (range, 38.8-79.9), 45.0 Gy-Eq (range, 25.1-51.0), and 13.8 Gy-Eq (range, 4.8-25.3), respectively. In the IV group, the maximal, mean, and minimal dose given to the gross tumor volume was 24.2 Gy-Eq (range, 21.5-29.9), 16.4 Gy-Eq (range, 14.5-20.2), and 7.8 Gy-Eq (range, 6.8-9.5), respectively. Within 1-3 months after BNCT, the responses were assessed. Of the 6 patients in the IV group, 2 had a partial response, 3 no change, and 1 had progressive disease. Of 4 patients in the IA group, 1 achieved a complete response and 3 a partial response. Conclusion: Intra-arterial administration of boronophenylalanine is a promising drug delivery system for head-and-neck BNCT.

Suzuki, Minoru [Particle Oncology Research Center, Research Reactor Institute, Kyoto University, Osaka (Japan)]. E-mail: msuzuki@rri.kyoto-u.ac.jp; Sakurai, Yoshinori [Division of Medical Physics, Department of Radiation Life Science, Research Reactor Institute, Kyoto University, Osaka (Japan); Nagata, Kenji [Particle Oncology Research Center, Research Reactor Institute, Kyoto University, Osaka (Japan); Kinashi, Yuko [Particle Oncology Research Center, Research Reactor Institute, Kyoto University, Osaka (Japan); Masunaga, Shinichiro [Particle Oncology Research Center, Research Reactor Institute, Kyoto University, Osaka (Japan); Ono, Koji [Particle Oncology Research Center, Research Reactor Institute, Kyoto University, Osaka (Japan); Maruhashi, Akira [Division of Medical Physics, Department of Radiation Life Science, Research Reactor Institute, Kyoto University, Osaka (Japan); Kato, Ituro [Department of Oral and Maxillofacial Surgery II, Osaka University Graduate School of Dentistry, Osaka (Japan); Fuwa, Nobukazu [Department of Radiation Oncology, Aichi Cancer Center, Aichi (Japan); Hiratsuka, Junichi [Department of Radiation Oncology, Kawasaki Medical School, Okayama (Japan); Imahori, Yoshio [Cancer Intelligence Care Systems, Inc., Tokyo (Japan)

2006-12-01T23:59:59.000Z

91

High energy neutron dosimeter  

DOE Patents (OSTI)

A device for measuring dose equivalents in neutron radiation fields is described. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning. 2 figures.

Rai, K.S.F.

1994-01-11T23:59:59.000Z

92

Proton recoil scintillator neutron rem meter  

DOE Patents (OSTI)

A neutron rem meter utilizing proton recoil and thermal neutron scintillators to provide neutron detection and dose measurement. In using both fast scintillators and a thermal neutron scintillator the meter provides a wide range of sensitivity, uniform directional response, and uniform dose response. The scintillators output light to a photomultiplier tube that produces an electrical signal to an external neutron counter.

Olsher, Richard H. (Los Alamos, NM); Seagraves, David T. (Los Alamos, NM)

2003-01-01T23:59:59.000Z

93

Irradiation hardening in unalloyed and ODS molybdenum during low dose neutron irradiation at 300 and 600?C  

SciTech Connect

Unalloyed molybdenum and oxide dispersion strengthened (ODS) molybdenum were irradiated at 300 C and 600 C in HFIR to neutron fluences of 0.2, 2.1, and 24.3 x 10{sup 24} n/m{sup 2} (E > 0.1 MeV). The size and number density of voids and loops as well as the measured irradiation hardening and electrical resistivity were found to increase sub-linearly with fluence. This supports the idea that the formation of the extended defects that produce irradiation hardening in molybdenum is the result of a nucleation and growth process rather than the formation of sessile defects directly from the displacement damage cascades. This conclusion is further supported by molecular dynamics (MD) simulations of cascade damage. The unalloyed molybdenum had a low impurity interstitial content with less irradiation hardening and lower change in electrical resistivity than is observed for ODS Mo. This result suggests that high-purity can result in slightly improved resistance to irradiation embrittlement in molybdenum at low fluences.

Snead, Lance Lewis [ORNL; Byun, Thak Sang [ORNL; Leonard, Keith J [ORNL; Smith, Richard W [Bechtel-Bettis, Inc.; Cockeram, Brian V [Bechtel-Bettis, Inc.

2008-01-01T23:59:59.000Z

94

Translocation analysis by the FISH-painting method for retrospective dose reconstruction in individuals exposed to ionizing radiation 10 years after exposure  

Science Journals Connector (OSTI)

Fluorescence in situ hybridization (FISH) is a powerful method largely used for detecting chromosomal rearrangements, translocations in particular, which are important biomarkers for dose assessment in case of human exposure to ionizing radiation. To test the possibility of using the translocation analysis by FISH-painting method in retrospective dose assessment, we carried out in vitro experiments in irradiated human lymphocytes, in parallel with the analysis of translocations in lymphocytes from 10 individuals, who were exposed to 137cesium in the Goiânia (Brazil) accident (samples collected 10 years after exposure). The in vitro dose–response curve for the genomic translocation frequencies (FGs) fits a linear quadratic model, according to the equation: Y=0.0243X2+0.0556X. The FG values were also calculated for the individuals exposed to 137cesium, ranging from 0.58 to 5.91 per 100 cells, and the doses were estimated and compared with the results obtained by dicentric analysis soon after the accident, taking the opportunity to test the validity of translocation analysis in retrospective biodosimetry. A tentative of retrospective dosimetry was performed, indicating that the method is feasible only for low level exposure (below 0.5 Gy), while for higher doses there is a need to apply appropriate correction factors, which take into consideration mainly the persistence of chromosomal translocations along with time, and the influence of endogenous and exogenous factors determining the inter-individual variability in the cellular responses to radiation.

Marjori L. Camparoto; Adriana T. Ramalho; Adayapalam T. Natarajan; Maria P. Curado; Elza T. Sakamoto-Hojo

2003-01-01T23:59:59.000Z

95

NEUTRON PRODUCTION BY NEUTRAL BEAM SOURCES  

E-Print Network (OSTI)

HORSE Code—A Hultigroup Neutron and Gamma-Say Honte CarloR. Smith, "A Tantalus Fast Neutron Integrator," UCRL-17051.FiS- 9 Neutron dose during 3 months of typical TSUI

Berkner, K.H.

2010-01-01T23:59:59.000Z

96

Approach for calculating population doses using the CIDER computer code  

SciTech Connect

This report describes an approach for calculating radiation doses for the Hanford Environmental Dose Reconstruction Project. The approach utilizes the CIDER computer code.

Shipler, D.B.

1993-04-29T23:59:59.000Z

97

Use of international data sets to evaluate and validate pathway assessment models applicable to exposure and dose reconstruction at DOE facilities. Monthly progress reports and final report, October--December 1994  

SciTech Connect

The objective of Task 7.lD was to (1) establish a collaborative US-USSR effort to improve and validate our methods of forecasting doses and dose commitments from the direct contamination of food sources, and (2) perform experiments and validation studies to improve our ability to predict rapidly and accurately the long-term internal dose from the contamination of agricultural soil. At early times following an accident, the direct contamination of pasture and food stuffs, particularly leafy vegetation and grain, can be of great importance. This situation has been modeled extensively. However, models employed then to predict the deposition, retention and transport of radionuclides in terrestrial environments employed concepts and data bases that were more than a decade old. The extent to which these models have been tested with independent data sets was limited. The data gathered in the former-USSR (and elsewhere throughout the Northern Hemisphere) offered a unique opportunity to test model predictions of wet and dry deposition, agricultural foodchain bioaccumulation, and short- and long-term retention, redistribution, and resuspension of radionuclides from a variety of natural and artificial surfaces. The current objective of this project is to evaluate and validate pathway-assessment models applicable to exposure and dose reconstruction at DOE facilities through use of international data sets. This project incorporates the activity of Task 7.lD into a multinational effort to evaluate models and data used for the prediction of radionuclide transfer through agricultural and aquatic systems to humans. It also includes participation in two studies, BIOMOVS (BIOspheric MOdel Validation Study) with the Swedish National Institute for Radiation Protection and VAMP (VAlidation of Model Predictions) with the International Atomic Energy Agency, that address testing the performance of models of radionuclide transport through foodchains.

Hoffman, F.O. [Senes Oak Ridge, Inc., TN (United States). Center for Risk Analysis

1995-04-01T23:59:59.000Z

98

A PC-Based Computer Program for the Estimation of the Radiation Dose in in Vitro and in Vivo Boron Neutron Capture Irradiation Experiments  

Science Journals Connector (OSTI)

In Boron Neutron Capture Therapy (BNCT) microdosimetry of charged particle radiation depends on total boron concentration and intracellular boron distribution. Due to the inhomogeneity of boron distribution in...

Ruud Verrijk; Rene Huiskamp; Adrian C. Begg

1993-01-01T23:59:59.000Z

99

Portable neutron spectrometer and dosimeter  

DOE Patents (OSTI)

The disclosure relates to a battery operated neutron spectrometer/dosimeter utilizing a microprocessor, a built-in tissue equivalent LET neutron detector, and a 128-channel pulse height analyzer with integral liquid crystal display. The apparatus calculates doses and dose rates from neutrons incident on the detector and displays a spectrum of rad or rem as a function of keV per micron of equivalent tissue and also calculates and displays accumulated dose in millirads and millirem as well as neutron dose rates in millirads per hour and millirem per hour.

Waechter, David A. (Los Alamos, NM); Erkkila, Bruce H. (Los Alamos, NM); Vasilik, Dennis G. (Los Alamos, NM)

1985-01-01T23:59:59.000Z

100

Prospectively ECG-triggered high-pitch coronary angiography with third-generation dual-source CT at 70 kVp tube voltage: Feasibility, image quality, radiation dose, and effect of iterative reconstruction  

Science Journals Connector (OSTI)

AbstractBackground Low tube voltage reduces radiation exposure in coronary CT angiography (CTA). Using 70 kVp tube potential has so far not been possible because CT systems were unable to provide sufficiently high tube current with low voltage. Objective We evaluated feasibility, image quality (IQ), and radiation dose of coronary CTA using a third-generation dual-source CT system capable of producing 450 mAs tube current at 70 kVp tube voltage. Methods Coronary CTA was performed in 26 consecutive patients with suspected coronary artery disease, selected for body weight pitch spiral acquisition was used. Filtered back projection (FBP) and iterative reconstruction (IR) algorithms were applied. IQ was assessed using a 4-point rating scale (1 = excellent, 4 = nondiagnostic) and objective parameters. Results Mean age was 62 ± 9 years (46% males; mean body mass index, 27.7 ± 3.8 kg/m2; mean heart rate, 54 ± 5 beats/min). Mean dose-length product was 20.6 ± 1.9 mGy × cm; mean estimated effective radiation dose was 0.3 ± 0.03 mSv. Diagnostic IQ was found in 365 of 367 (FBP) and 366 of 367 (IR) segments (P nonsignificant). IQ was rated “excellent” in 53% (FBP) and 86% (IR) segments (P = .001) and “nondiagnostic” in 2 (FBP) and 1 segment (IR) (P nonsignificant). Mean IQ score was lesser in FBP vs IR (1.5 ± 0.4 vs 1.1 ± 0.2; P pitch spiral acquisition and 70 kVp tube voltage is feasible and provides both robust IQ and very low radiation exposure.

Michaela M. Hell; Daniel Bittner; Annika Schuhbaeck; Gerd Muschiol; Michael Brand; Michael Lell; Michael Uder; Stephan Achenbach; Mohamed Marwan

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Prediction of proton and neutron absorbed-dose distributions in proton beam radiation therapy using Monte Carlo n-particle transport code (MCNPX)  

E-Print Network (OSTI)

The objective of this research was to develop a complex MCNPX model of the human head to predict absorbed dose distributions during proton therapy of ocular tumors. Absorbed dose distributions using the complex geometry were compared to a simple...

Massingill, Brian Edward

2009-05-15T23:59:59.000Z

102

Iraq Reconstruction.  

E-Print Network (OSTI)

??The invasion planning, execution and ongoing reconstruction operations in Iraq are extremely complex. Using research, personal experience and experience of deployed members, this paper documents… (more)

Bradley, Judah C.

2006-01-01T23:59:59.000Z

103

Boron Neutron Capture Therapy for Murine Malignant Gliomas  

Science Journals Connector (OSTI)

...and epithermal neutron component comprised approximately 5% of the total dose; the majority (~80%) came from the boron-10 reaction and the rest from photons and thermal neutrons (data not shown). All subsequently described BNCT doses are...

Stephen C. Saris; Guido R. Solares; David E. Wazer; Guillermo Cano; Sarah E. Kerley; Melita A. Joyce; Lester S. Adelman; Otto K. Harling; Hywel Madoc-Jones; Robert G. Zamenhof

1992-09-01T23:59:59.000Z

104

Fast neutron Damage Studies on NdFeB Materials  

E-Print Network (OSTI)

used in the SLAC Photon and Neutron Fields”, SLAC-PUB-8517,SLAC-PUB-11219 May2005 Fast Neutron Damage Studies on NdFeBrst mea- surements of fast neutron, stepped doses at the UC

2005-01-01T23:59:59.000Z

105

Cylindrical Detector and Preamplifier Design for Detecting Neutrons  

E-Print Network (OSTI)

neutrons because the recoil protons do not cross the detectors. Proportional counters simulating different site-sizes can be used to get a better neutron dose equivalent measurement since the range and stopping power of protons generated by neutrons...

Xia, Zhenghua

2010-01-14T23:59:59.000Z

106

E-Print Network 3.0 - ascending dose study Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

by Summary: -regularized reconstruction (PSRR) method was proposed to reduce radiation dose and applied to lung perfusion studies. Normal... and ultra-low-dose lung computed...

107

Short and long-term exposure of CNS cell lines to BPA-f a radiosensitizer for Boron Neutron Capture Therapy: safety dose evaluation by a battery of cytotoxicity tests  

Science Journals Connector (OSTI)

Despite the current clinical use of boronophenylalanine-fructose (BPA-f), as radiosensitizer, in BNCT application for brain tumors, still remains to be determined the safety dose of this agent. We evaluated the potential risk of primary BPA-f toxicity before neutronic irradiation at different concentrations (0–100 ?g Beq/ml) after short- and long-term exposure (4–48 h and 7–10 days), using a battery of tests (i.e. MTT assay, calcein-AM/Propidium Iodide staining, clonogenic test) in CNS cell models (D384 and SH-SY5Y), and non-neuronal primary human fibroblasts (F26). MTT data showed: (i) no cytotoxic effects after short-term exposure (4 h) to any of BPA-f concentrations tested in all cell models; (ii) dose- and time-dependent mitochondrial activity impairment in D384 and SH-SY5Y cells only (with 60% and 40% cell death in D384 and SH-SY5Y, respectively, after 48 h exposure to BPA-f 100 ?g Beq/ml). By Calcein-AM/PI staining, BPA-f treatment was specific toward SH-SY5Y cells only: a dose-dependent cell density reduction was observed, with a more pronounced effect after 48 h exposure (15–40% at doses ranging 20–100 ?g Beq/ml). Clonogenic data revealed dose-dependent decrease of cell proliferative capacity in all cell lines, still the SH-SY5Y cells were the most sensitive ones: the lowest dose (20 ?g Beq/ml) produced 90% cell decrease. These results indicate dose- and time-dependent cytotoxic effects of BPA-f, with CNS cells showing a lower tolerance compared to fibroblasts. Long-term exposure to BPA-f compromised the proliferative capacity regardless of cell model type (cell sensitivity being SH-SY5Y > D384 > F26). In short-time exposure, BPA-f exhibits a safe dosage up to 40 ?g Beq/ml for the viability of CNS cell lines.

U. De Simone; L. Manzo; C. Ferrari; J. Bakeine; C. Locatelli; T. Coccini

2013-01-01T23:59:59.000Z

108

EPR dosimetry in a mixed neutron and gamma radiation field  

Science Journals Connector (OSTI)

......radicals induced by ionizing...of radio-induced free radicals...Mura, the neutron dose component...neutrons of energy comparable to fission spectrum(15...component of thermal neutron in the SILENE...34 for fission neutrons...shape line spectrum modification...SILENE neutron energies. Nevertheless......

F. Trompier; P. Fattibene; D. Tikunov; A. Bartolotta; A. Carosi; M. C. Doca

2004-08-01T23:59:59.000Z

109

Neutron reflectometry  

Science Journals Connector (OSTI)

Neutron reflectivity is a powerful tool for the ... chapter include: the theory of elastic specular neutron diffraction; polarized neutron reflectivity; surface roughness; experimental methodology; resolution in ...

G. S. Smith; C. F. Majkrzak

2004-01-01T23:59:59.000Z

110

Neutron-Neutron Interaction  

Science Journals Connector (OSTI)

The present status of the problem of charge dependence is discussed. The information about the neutron-neutron interaction derived from the two-neutron system, three-nucleon systems, final-state interactions in multiparticle reactions, and peripheral processes is critically evaluated. The experimental data indicate the breakdown of charge independence by about 3-5%. Evidence concerning the violation of charge symmetry is inconclusive, but it seems that most of the data are consistent with the assumption that charge symmetry is satisfied within 0.5-1%. The most suitable studies which might improve the knowledge of the neutron-neutron forces are indicated.

IVO ŠLAUS

1967-07-01T23:59:59.000Z

111

Smoothing Wavelet Reconstruction  

E-Print Network (OSTI)

EdgeXchild and processEdgeYchild ................................ 36 Figure 15. Reconstructing Stanford Bunny ...................................................................... 37 Figure 16. Reconstructing EPFL Aquarius... ...................................................................... 38 Figure 17. Reconstructing Stanford Bunny (front) .......................................................... 41 Figure 18. Reconstructing Stanford Bunny (back) ........................................................... 41 Figure 19...

Garg, Deepak

2013-04-23T23:59:59.000Z

112

RELATIVE ATTENUATION CHARACTERISTICS OF SOME SHIELDING MATERIALS FOR PuB NEUTRONS  

E-Print Network (OSTI)

for the Neutron Conversion Factors," Health Physics Flux-to~to dose-equivalent conversion factors are those taken fromsion factors " The conversion factors for neutrons

Bringham, P.S.

2010-01-01T23:59:59.000Z

113

Secondary neutrons in clinical proton radiotherapy: A charged issue  

E-Print Network (OSTI)

-body neutron dose, due to interactions of the protons with the scattering and collimating beam elements radiotherapy; Secondary neutrons; Second cancers; Passive scattering The development of hospital-based proton on establishing the neutron doses involved [7­20], there is still no agree- ment about whether these scattered

Brenner, David Jonathan

114

NEUTRON FLUX DENSITY AND SECONDARY-PARTICLE ENERGY SPECTRA AT THE 184-INCH SYNCHROCYCLOTRON MEDICAL FACILITY  

E-Print Network (OSTI)

Mischke, R. E. 1973a. Neutron-nucleus total and inelasticproduction of high-energy neutrons by stripping. Phys. Rev.1975. Dose rate due to neutrons around the alpha- Health

Smith, A.R.

2010-01-01T23:59:59.000Z

115

A new technique for beta attenuation studies in neutron activation foils using 4?- coincidence system  

Science Journals Connector (OSTI)

......low flux neutron measurements...low flux neutron measurements...Characteristics of the neutron activation...Resonance energy (eV) Resonance...46 barn (fission spectrum averaged...dose, the induced activity...irradiated in the thermal column of......

Deepa Sathian; M. P. Chougaonkar; Y. S. Mayya

2010-12-01T23:59:59.000Z

116

Neutron Polarimetry  

Science Journals Connector (OSTI)

8 July 1993 research-article Neutron Polarimetry P. Jane Brown J. Bruce Forsyth Francis Tasset Zero-field neutron polarimetry is a technique which has...polarization analysis to be carried out in a neutron scattering experiment. The incident...

1993-01-01T23:59:59.000Z

117

Field-size dependence of doses of therapeutic carbon beams  

SciTech Connect

To estimate the physical dose at the center of spread-out Bragg peaks (SOBP) for various conditions of the irradiation system, a semiempirical approach was applied. The dose at the center of the SOBP depends on the field size because of large-angle scattering particles in the water phantom. For a small field of 5x5 cm{sup 2}, the dose was reduced to 99.2%, 97.5%, and 96.5% of the dose used for the open field in the case of 290, 350, and 400 MeV/n carbon beams, respectively. Based on the three-Gaussian form of the lateral dose distributions of the carbon pencil beam, which has previously been shown to be effective for describing scattered carbon beams, we reconstructed the dose distributions of the SOBP beam. The reconstructed lateral dose distribution reproduced the measured lateral dose distributions very well. The field-size dependencies calculated using the reconstructed lateral dose distribution of the therapeutic carbon beam agreed with the measured dose dependency very well. The reconstructed beam was also used for irregularly shaped fields. The resultant dose distribution agreed with the measured dose distribution. The reconstructed beams were found to be applicable to the treatment-planning system.

Kusano, Yohsuke; Kanai, Tatsuaki; Yonai, Shunsuke; Komori, Masataka; Ikeda, Noritoshi; Tachikawa, Yuji; Ito, Atsushi; Uchida, Hirohisa [Tokai University Unified Graduate School, Graduate School of Science and Technology, 1117 Kitakaname, Hiratsuka, Kanagawa 259-1207, Japan and Accelerator Engineering Co., 2-13-1 Konakadai, Inage-ku, Chiba 263-0043 (Japan); Department of Accelerator Physics and Medical Physics, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba 263-8555 (Japan); Medical Physics Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba 263-8555 (Japan); Department of Accelerator Physics and Medical Physics, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba, Chiba 263-8555 (Japan); Accelerator Engineering Co., 2-13-1 Konakadai, Inage-ku, Chiba 263-0043 (Japan); Department of Energy Science and Engineering, School of Engineering, Tokai University, 1117 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan)

2007-10-15T23:59:59.000Z

118

Design and Simulation of a Boron-loaded Neutron Spectrometer  

E-Print Network (OSTI)

The measurement of the distribution of kinetic energy carried by neutron particles is of interest to the health physics and radiation protection industry. Neutron particle spectral fluence is essential to the calculation of absorbed dose, equivalent...

Martin, Thomas

2012-10-19T23:59:59.000Z

119

Neutron Production, Neutron Facilities and Neutron Instrumentation  

Science Journals Connector (OSTI)

...Mexico, 87545, U.S.A, e-mail: sven@lanl.gov Hans-Georg Priesmeyer Geesthacht Neutron Scattering Facility, GKSS Research Center, 21502 Geesthacht, Germany, e-mail: hans-georg.priesmeyer@gkss.de NEUTRON GENERATION The...

Sven C. Vogel; Hans-Georg Priesmeyer

120

Neutron Reflectivity  

Science Journals Connector (OSTI)

Neutron Reflectivity ... This article is part of the Neutron Reflectivity special issue. ... The articles in this special issue on neutron reflectivity cover a broad range of the applications of this technique and the related X-ray and neutron scattering experiments of SAXS, SANS, GISAXS, and GISANS. ...

Jeffrey Penfold

2009-03-31T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

About Neutrons  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Basics Neutron Basics A neutron is one of the fundamental particles that make up matter. This uncharged particle exists in the nucleus of a typical atom, along with its positively charged counterpart, the proton. Protons and neutrons each have about the same mass, and both can exist as free particles away from the nucleus. In the universe, neutrons are abundant, making up more than half of all visible matter. Find Out What a Neutron Is Youtube icon Properties of Neutrons How Can Neutrons Be Used for Research? Image of glucose movement in plants Neutron imaging techniques have been able to determine the precise movement of glucose in plants. This knowledge can help scientists better understand how biomass can be efficiently converted into fuel. Neutrons have many properties that make them ideal for certain types of

122

Observation of Neutron Skyshine from an Accelerator Based Neutron Source  

SciTech Connect

A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >10{sup 11} n{center_dot}s{sup -1}. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

Franklyn, C. B. [Radiation Science Department, Necsa, PO Box 582, Pretoria 0001 (South Africa)

2011-12-13T23:59:59.000Z

123

Dose imaging with gel-dosemeter layers: optical analysis and dedicated software  

Science Journals Connector (OSTI)

......Fricke-gel dosimetry in boron neutron capture therapy...all dose components in boron neutron capture therapy...Three-dimensional determination of absorbed dose by spectrophotometric...gel matrix of suitable isotopes does not sensibly alter...improving its suitability to boron neutron capture therapy......

G. Gambarini; M. Carrara; S. Gay; S. Tomatis

2006-09-01T23:59:59.000Z

124

E-Print Network 3.0 - assigning dose based Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Yu, Ph... -regularized reconstruction (PSRR) method was proposed to reduce radiation dose and applied to lung perfusion ... Source: Virginia Tech - Wake Forest University School...

125

Neutron-Neutron Scattering Length  

Science Journals Connector (OSTI)

The final-state interaction of the two neutrons from the reaction ?-+d?2n+? has a pronounced and distinctive effect on the momentum spectrum of the outgoing particles. In particular, the neutron spectrum is sharply peaked in the neighborhood of 2 Mev, with a shape that is quite sensitive to the strength of the nn interaction. In the region of this peak, the relative neutron-neutron momentum is so small that the nn interaction is completely characterized by its scattering length. Hence it is proposed that a measurement of the shape of the neutron spectrum from this reaction may provide a convenient means of measuring the neutron-neutron scattering length. Neutron spectra are calculated in an impulse approximation, for several assumed values of the scattering length. It appears from their shapes that, in this way, present neutron-detection techniques should be capable of determining the scattering length to within 25%.

Kirk W. McVoy

1961-03-01T23:59:59.000Z

126

Dose Limits  

Energy.gov (U.S. Department of Energy (DOE))

Dose Limits ERAD (Question Posted to ERAD in May 2012) Who do you define as a member of the public for the onsite MEI? This question implies that there may be more than one maximally exposed individual (MEI), one on-site and one off-site, when demonstrating compliance with the Public Dose Limit of DOE Order 458.1. Although all potential MEIs should be considered and documented, as well as the calculated doses and pathways considered, the intent of DOE Order 458.1 is in fact to ultimately identify only one MEI, a theoretical individual who could be either on-site or off-site.

127

Personnel electronic neutron dosimeter  

DOE Patents (OSTI)

A personnel electronic dosimeter includes a neutron-proton and neutron-alpha converter for providing an electrical signal having a magnitude proportional to the energy of a detected proton or alpha particle produced from the converter, a pulse generator circuit for generating a pulse having a duration controlled by the weighed effect of the amplitude of the electrical signal, an oscillator enabled by the pulse for generating a train of clock pulses for a time dependent upon the pulse length, a counter for counting the clock pulses, and an indicator for providing a direct reading and aural alarm when the count indicates that the wearer has been exposed to a selected level of neutron dose equivalent.

Falk, Roger B. (Lafayette, CO); Tyree, William H. (Boulder, CO)

1984-12-18T23:59:59.000Z

128

Personnel electronic neutron dosimeter  

DOE Patents (OSTI)

A personnel electronic dosimeter includes a neutron-proton and neutron-alpha converter for providing an electrical signal having a magnitude proportional to the energy of a detected proton or alpha particle produced from the converter, a pulse generator circuit for generating a pulse having a duration controlled by the weighed effect of the amplitude of the electrical signal, an oscillator enabled by the pulse for generating a train of clock pulses for a time dependent upon the pulse length, a counter for counting the clock pulses, and an indicator for providing a direct reading and aural alarm when the count indicates that the wearer has been exposed to a selected level of neutron dose equivalent.

Falk, R.B.; Tyree, W.H.

1982-03-03T23:59:59.000Z

129

Neutron skins and neutron stars  

SciTech Connect

The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ('PREX') at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in {sup 208}Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron beams may impact the physics of neutron stars.

Piekarewicz, J. [Department of Physics, Florida State University, Tallahassee, FL 32306-4350 (United States)

2013-11-07T23:59:59.000Z

130

Boron neutron capture enhancement of fast neutron radiotherapy  

Science Journals Connector (OSTI)

Clinical trials have revealed a therapeutic advantage for fast neutron radiation over conventional photon radiation for salivary gland cancer prostate cancer sarcoma and a subgroup of lung cancer. Conversely fast neutron treatment of high grade astrocytic brain tumors [glioblastoma multiforme (GBM)] resulted in tumor sterilization but also caused significant brain injury such that no therapeutic gain was attained. This effect was important however in that photon radiation and other conventional treatments have not demonstrated sterilization of GBM at any dose. Recent laboratory studies demonstrated that the hospital-based fast neutron beam from the University of Washington cyclotron has a thermal neutron component that may be used in a boron-10 neutron capture (BNC) reaction to enhance cell kill. The degree of enhancement was approximately 10 fold and was dependent upon the boron-10 concentration the boron-10 carrier agent and the fast neutron dose per fraction. The results of these experiments will be discussed in the context of creating a therapeutic window for treatment of glioblastoma using BNC-enhanced fast neutron radiation in a clinically tolerable regimen.

K. J. Stelzer; G. E. Laramore; R. Risler; L. Wiens; T. W. Griffin

1997-01-01T23:59:59.000Z

131

Neutron scattering  

Science Journals Connector (OSTI)

... likely to be able to contribute to many different branches of chemistry and secondly because neutron ...neutronscattering ...

A. J. Leadbetter

1977-12-01T23:59:59.000Z

132

Characterization of a neutron calibration range  

E-Print Network (OSTI)

sealed Rossi chamber, an Andersson-Braun type neutron rem counter, and CR-390 material track etch dosimeters. The theoretical dose equivalent rate, neglecting scattering, was calculated for the purpose of ensuring that the measurements obtained were...

Menchaca, Daniel Isidoro

2012-06-07T23:59:59.000Z

133

Computer simulation of neutron capture therapy.  

E-Print Network (OSTI)

Analytical methods are developed to simulate on a large digital computer the production and use of reactor neutron beams f or boron capture therapy of brain tumors. The simulation accounts for radiation dose distributions ...

Olson, Arne Peter

1967-01-01T23:59:59.000Z

134

Computer simulation of neutron capture therapy  

E-Print Network (OSTI)

Analytical methods are developed to simulate on a large digital computer the production and use of reactor neutron beams f or boron capture therapy of brain tumors. The simulation accounts for radiation dose distributions ...

Olson, Arne Peter

1967-01-01T23:59:59.000Z

135

Neutron guide  

DOE Patents (OSTI)

A neutron guide in which lengths of cylindrical glass tubing have rectangular glass plates properly dimensioned to allow insertion into the cylindrical glass tubing so that a sealed geometrically precise polygonal cross-section is formed in the cylindrical glass tubing. The neutron guide provides easier alignment between adjacent sections than do the neutron guides of the prior art.

Greene, Geoffrey L. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

136

Neutron Diffraction  

Science Journals Connector (OSTI)

22 February 1949 research-article Neutron Diffraction G. E. Bacon J. Thewlis The problem of neutron diffraction by crystals is treated by analogy...deals with a comparison between X-ray and neutron diffraction and it is shown that quantitatively...

1949-01-01T23:59:59.000Z

137

A toolkit for epithermal neutron beam characterisation in BNCT  

Science Journals Connector (OSTI)

......neutron fluence spectra calculated...function of neutron energy, data from...USA (new fission converter...free-beam spectrum and dose...beam and neutron and gamma...water phantom thermal and epithermal...The MnRR is induced basically......

Iiro Auterinen; Tom Serén; Jouni Uusi-Simola; Antti Kosunen; Sauli Savolainen

2004-08-01T23:59:59.000Z

138

Neutron skins and neutron stars  

Science Journals Connector (OSTI)

Background: The neutron skin of a heavy nucleus as well as many neutron-star properties are highly sensitive to the poorly constrained density dependence of the symmetry energy.Purpose: To provide for the first time meaningful theoretical errors and to assess the degree of correlation between the neutron-skin thickness of 208Pb and several neutron-star properties.Methods: A proper covariance analysis based on the predictions of an accurately calibrated relativistic functional “FSUGold” is used to quantify theoretical errors and correlation coefficients.Results: We find correlation coefficients of nearly 1 (or ?1) between the neutron-skin thickness of 208Pb and a host of observables of relevance to the structure, dynamics, and composition of neutron stars.Conclusions: We suggest that a follow-up Lead Radius Experiment (PREX) measurement, ideally with a 0.5% accuracy, could significantly constrain the equation of state of neutron-star matter.

F. J. Fattoyev and J. Piekarewicz

2012-07-05T23:59:59.000Z

139

Neutron Scattering Tutorials | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Scattering Tutorials SHARE Neutron Scattering Tutorials The following lectures were presented at the 2011 and 2010 National School on Neutron & X-Ray Scattering. This...

140

Neutron detector  

DOE Patents (OSTI)

A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

Stephan, Andrew C. (Knoxville, TN); Jardret; Vincent D. (Powell, TN)

2011-04-05T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Neutron Scattering  

Science Journals Connector (OSTI)

... Magnetic Neutron Diffraction By Yurii A. Izyumov and Ruslan P. Ozerov. Translated from the Russian. ... York; Heydon: London, June 1970.) 350s; $37.50; 150 DM.

G. L. SQUIRES

1970-12-05T23:59:59.000Z

142

3D heart reconstruction.  

E-Print Network (OSTI)

??The purpose of this thesis was to achieve a 3D reconstruction of the four heart chambers using 2D echocardiographic images. A level set algorithm based… (more)

Roxo, Diogo

2011-01-01T23:59:59.000Z

143

Neutron activation analysis  

Science Journals Connector (OSTI)

Neutron activation analysis ... Describes the science and techniques of neutron activation analysis. ...

H. R. Lukens

1967-01-01T23:59:59.000Z

144

Experimental setup for the determination of the correction factors of the neutron doseratemeters in fast neutron fields  

SciTech Connect

The use of the U-120 Cyclotron of the IFIN-HH allowed to perform a testing bench with fast neutrons in order to determine the correction factors of the doseratemeters dedicated to neutron measurement. This paper deals with researchers performed in order to develop the irradiation facility testing the fast neutrons flux generated at the Cyclotron. This facility is presented, together with the results obtain in determining the correction factor for a doseratemeter dedicated to the neutron dose equivalent rate measurement.

Iliescu, Elena; Bercea, Sorin; Dudu, Dorin; Celarel, Aurelia [National Institute of R and D for Physics and Nuclear Engineering-Horia Hulubei, Reactorului 30 St, P.O.BOX MG-6,Magurele, cod 077125 (Romania)

2013-12-16T23:59:59.000Z

145

Oak Ridge Health Studies Phase 1 report, Volume 2: Part A, Dose Reconstruction Feasibility Study. Tasks 1 and 2, A summary of historical activities on the Oak Ridge Reservation with emphasis on information concerning off-site emissions of hazardous materials  

SciTech Connect

The Phase I feasibility study has focused on determining the availability of information for estimating exposures of the public to chemicals and radionuclides released as a result of historical operation of the facilities at the Oak Ridge Reservation (ORR). The estimation of such past exposures is frequently called dose reconstruction. The initial project tasks, Tasks 1 and 2 were designed to identify and collect information that documents the history of activities at the ORR that resulted in the release of contamination and to characterize the availability of data that could be used to estimate the magnitude of the contaminant releases or public exposures. A history of operations that are likely to have generated off-site releases has been documented as a result of Task 1 activities. The activities required to perform this task involved the extensive review of historical operation records and interviews with present and past employees as well as other knowledgeable individuals. The investigation process is documented in this report. The Task 1 investigations have led to the documentation of an overview of the activities that have taken place at each of the major complexes, including routine operations, waste management practices, special projects, and accidents and incidents. Historical activities that appear to warrant the highest priority in any further investigations were identified based on their likely association with off-site emissions of hazardous materials as indicated by the documentation reviewed or information obtained in interviews.

Bruce, G.M.; Buddenbaum, J.E.; Lamb, J.K.; Widner, T.E.

1993-09-01T23:59:59.000Z

146

Lithium-6 filter for a fission converter-based Boron Neutron Capture Therapy irradiation facility beam  

E-Print Network (OSTI)

(cont.) A storage system was designed to contain the lithium-6 filter safely when it is not in use. A mixed field dosimetry method was used to measure the photon, thermal neutron and fast neutron dose. The measured advantage ...

Gao, Wei, Ph. D.

2005-01-01T23:59:59.000Z

147

Neutron Microscope  

Science Journals Connector (OSTI)

We report successful operation of a neutron microscope using ultracold neutrons at the high-flux reactor at Grenoble. A sharp, achromatic image of an object slit was obtained at a magnification of 50. The measured resolution of 0.1 mm was limited mainly by the available beam intensity, not by aberrations.

P. Herrmann; K. -A. Steinhauser; R. Gähler; A. Steyerl; W. Mampe

1985-05-06T23:59:59.000Z

148

Neutron scattering  

Science Journals Connector (OSTI)

... statements that the EMBL outstation in Grenoble "[has an] uncertain future" and that "neutrons have not turned out to be particularly useful for biologists" in Peter Newmark's ... on the European Molecular Biology Laboratory (Nature 338, 724; 1989) require some comment.Neutron ...

S. CUSACK; B. JACROT; R. LEBERMAN; R. MAY; P. TlMMINS; G. ZACCAI

1989-06-01T23:59:59.000Z

149

Neutron Polarization  

Science Journals Connector (OSTI)

The production of polarized neutrons in magnetized iron has been studied, using the intense neutron beams available at the Argonne heavy water pile. The theoretical work of Halpern et al., used as a guide in the experiments, has been checked in many respects, with the exception that the polarization cross section p has a measured value of 3.15 barns compared to the theoretical 1 barn. The application of neutron polarization to the measurement of the approach to saturation in ferromagnets is described and preliminary results are reported.

D. J. Hughes; J. R. Wallace; R. H. Holtzman

1948-06-01T23:59:59.000Z

150

Thermal neutron detection system  

DOE Patents (OSTI)

According to the present invention, a system for measuring a thermal neutron emission from a neutron source, has a reflector/moderator proximate the neutron source that reflects and moderates neutrons from the neutron source. The reflector/moderator further directs thermal neutrons toward an unmoderated thermal neutron detector.

Peurrung, Anthony J. (Richland, WA); Stromswold, David C. (West Richland, WA)

2000-01-01T23:59:59.000Z

151

Enhancement of absolute neutron dosimetry by activation technique  

Science Journals Connector (OSTI)

In this work, an activation technique was used for absolute neutron dosimetry. Induced gamma within two activation foils (115In and 197Au) was detected by (5 × 5) sodium iodide (NaI) crystal. Thermal neutron irradiation was performed using the thermal neutron irradiation facility at the National Institute for Standards (NIS). Two gamma lines of 416.9 keV and 411.8 keV from 115In and 198Au, respectively, were chosen for the estimation of the neutron fluence. Gamma lines of 416.8 keV and 1293.56 keV from 115In were used to assure the obtained values of neutron fluence. Absolute neutron dose was calculated utilising the measured neutron fluence. Estimated neutron dose was found to be 1.50 mSv/h. The calculated dose by activation technique was verified by neutron rem meter NM2. Enhancement of neutron fluence was performed by adding Perspex sheets behind the activation foils to produce multiple scattering on the foils, and hence resulting in increasing the capability of accurate estimation of low neutron fluence.

A.R. El-Sersy; N.E. Khaled; S.A. Eman

2012-01-01T23:59:59.000Z

152

Neutron Checkup  

Science Journals Connector (OSTI)

Neutron activation analysis is yet another technique in the arsenal of diagnostic methods that physicians can draw on to examine the health of their patients. The University of Washington's school of medicine in Seattle is the first facility in the ...

1969-11-10T23:59:59.000Z

153

Neutron Reflectometry  

Science Journals Connector (OSTI)

Neutron reflectometry is a relatively new technique [1,2]. In the last years, it has been extensively used for solving soft matter problems like polymer mixing [3,4] or the structure of liquids at the surface [5,

Claude Fermon; Frédéric Ott; Alain Menelle

1999-01-01T23:59:59.000Z

154

Neutron Tomography and Space  

E-Print Network (OSTI)

Kevin Shields, “Optimization of neutron tomography for rapidNEUTRON TOMOGRAPHY AND SPACE Hal Egbert, Ronald Walker, R.industrial applications[1]. Neutron Computed Tomography was

Egbert, Hal; Walker, Ronald; Flocchini, R.

2007-01-01T23:59:59.000Z

155

Neutron range spectrometer  

DOE Patents (OSTI)

A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are colliminated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. 1 fig.

Manglos, S.H.

1988-03-10T23:59:59.000Z

156

Design of a boron neutron capture enhanced fast neutron therapy assembly  

SciTech Connect

The use of boron neutron capture to boost tumor dose in fast neutron therapy has been investigated at several fast neutron therapy centers worldwide. This treatment is termed boron neutron capture enhanced fast neutron therapy (BNCEFNT). It is a combination of boron neutron capture therapy (BNCT) and fast neutron therapy (FNT). It is believed that BNCEFNT may be useful in the treatment of some radioresistant brain tumors, such as glioblastoma multiform (GBM). A boron neutron capture enhanced fast neutron therapy assembly has been designed for the Fermilab Neutron Therapy Facility (NTF). This assembly uses a tungsten filter and collimator near the patient's head, with a graphite reflector surrounding the head to significantly increase the dose due to boron neutron capture reactions. The assembly was designed using Monte Carlo radiation transport code MCNP version 5 for a standard 20x20 cm{sup 2} treatment beam. The calculated boron dose enhancement at 5.7-cm depth in a water-filled head phantom in the assembly with a 5x5 cm{sup 2} collimation was 21.9% per 100-ppm {sup 10}B for a 5.0-cm tungsten filter and 29.8% for a 8.5-cm tungsten filter. The corresponding dose rate for the 5.0-cm and 8.5-cm thick filters were 0.221 and 0.127 Gy/min, respectively; about 48.5% and 27.9% of the dose rate of the standard 10x10 cm{sup 2} fast neutron treatment beam. To validate the design calculations, a simplified BNCEFNT assembly was built using four lead bricks to form a 5x5 cm{sup 2} collimator. Five 1.0-cm thick 20x20 cm{sup 2} tungsten plates were used to obtain different filter thicknesses and graphite bricks/blocks were used to form a reflector. Measurements of the dose enhancement of the simplified assembly in a water-filled head phantom were performed using a pair of tissue-equivalent ion chambers. One of the ion chambers is loaded with 1000-ppm natural boron (184-ppm {sup 10}B) to measure dose due to boron neutron capture. The measured dose enhancement at 5.0-cm depth in the head phantom for the 5.0-cm thick tungsten filter is (16.6 {+-} 1.8)%, which agrees well with the MCNP simulation of the simplified BNCEFNT assembly, (16.4 {+-} 0.5)%. The error in the calculated dose enhancement only considers the statistical uncertainties. The total dose rate measured at 5.0-cm depth using the non-borated ion chamber is (0.765 {+-} 0.076) Gy/MU, about 61% of the fast neutron standard dose rate (1.255Gy/MU) at 5.0-cm depth for the standard 10x10 cm{sup 2} treatment beam. The increased doses to other organs due to the use of the BNCEFNT assembly were calculated using MCNP5 and a MIRD phantom. The activities of the activation products produced in the BNCEFNT assembly after neutron beam delivery were computed. The photon ambient dose rate due to the radioactive activation products was also estimated.

Wang, Zhonglu; /Georgia Tech; ,

2006-08-01T23:59:59.000Z

157

Internal Dose Estimates from  

E-Print Network (OSTI)

Appendix F Internal Dose Estimates from NTS Fallout F-1 #12;Radiation Dose to the Population;TABLE OF CONTENTS Page F- Part I. Estimates of Dose...........................................................................................40 Comparison to dose estimates from global fallout

158

A study on the optimum fast neutron flux for Boron Neutron Capture Therapy of deep-seated tumors  

Science Journals Connector (OSTI)

Abstract High-energy neutrons, named fast neutrons which have a number of undesirable biological effects on tissue, are a challenging problem in beam designing for Boron Neutron Capture Therapy, BNCT. In spite of this fact, there is not a widely accepted criterion to guide the beam designer to determine the appropriate contribution of fast neutrons in the spectrum. Although a number of researchers have proposed a target value for the ratio of fast neutron flux to epithermal neutron flux, it can be shown that this criterion may not provide the optimum treatment condition. This simulation study deals with the determination of the optimum contribution of fast neutron flux in the beam for BNCT of deep-seated tumors. Since the dose due to these high-energy neutrons damages shallow tissues, delivered dose to skin is considered as a measure for determining the acceptability of the designed beam. To serve this purpose, various beam shaping assemblies that result in different contribution of fast neutron flux are designed. The performances of the neutron beams corresponding to such configurations are assessed in a simulated head phantom. It is shown that the previously used criterion, which suggests a limit value for the contribution of fast neutrons in beam, does not necessarily provide the optimum condition. Accordingly, it is important to specify other complementary limits considering the energy of fast neutrons. By analyzing various neutron spectra, two limits on fast neutron flux are proposed and their validity is investigated. The results show that considering these limits together with the widely accepted IAEA criteria makes it possible to have a more realistic assessment of sufficiency of the designed beam. Satisfying these criteria not only leads to reduction of delivered dose to skin, but also increases the advantage depth in tissue and delivered dose to tumor during the treatment time. The Monte Carlo Code, MCNP-X, is used to perform these simulations.

Fatemeh S. Rasouli; S. Farhad Masoudi

2015-01-01T23:59:59.000Z

159

Neutron source in the MCNPX shielding calculating for electron accelerator driven facility  

SciTech Connect

Argonne National Laboratory (ANL) of USA and Kharkov Inst. of Physics and Technology (KIPT) of Ukraine have been collaborating on the design development of an experimental neutron source facility. It is an accelerator driven system (ADS) utilizing a subcritical assembly driven by electron accelerator. The facility will be utilized for performing basic and applied nuclear researches, producing medical isotopes, and training young nuclear specialists. Monte Carlo code MCNPX has been utilized as a design tool due to its capability to transport electrons, photons, and neutrons at high energies. However the facility shielding calculations with MCNPX need enormous computational resources and the small neutron yield per electron makes sampling difficulty for the Monte Carlo calculations. A method, based on generating and utilizing neutron source file, was proposed and tested. This method reduces significantly the required computer resources and improves the statistics of the calculated neutron dose outside the shield boundary. However the statistical errors introduced by generating the neutron source were not directly represented in the results, questioning the validity of this methodology, because an insufficiently sampled neutron source can cause error on the calculated neutron dose. This paper presents a procedure for the validation of the generated neutron source file. The impact of neutron source statistic on the neutron dose is examined by calculating the neutron dose as a function of the number of electron particles used for generating the neutron source files. When the value of the calculated neutron dose converges, it means the neutron source has scored sufficient records and statistic does not have apparent impact on the calculated neutron dose. In this way, the validity of neutron source and the shield analyses could be verified. (authors)

Zhong, Z.; Gohar, Y. [Nuclear Engineering Div., Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

2012-07-01T23:59:59.000Z

160

Reconstruction algorithms for MRI  

E-Print Network (OSTI)

This dissertation presents image reconstruction algorithms for Magnetic Resonance Imaging (MRI) that aims to increase the imaging efficiency. Algorithms that reduce imaging time without sacrificing the image quality and ...

Bilgic?, Berkin

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
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161

Overview of Image Reconstruction  

SciTech Connect

Image reconstruction (or computerized tomography, etc.) is any process whereby a function, f, on Rn is estimated from empirical data pertaining to its integrals, ∫f(x) dx, for some collection of hyperplanes of dimension k < n. The paper begins with background information on how image reconstruction problems have arisen in practice, and describes some of the application areas of past or current interest; these include radioastronomy, optics, radiology and nuclear medicine, electron microscopy, acoustical imaging, geophysical tomography, nondestructive testing, and NMR zeugmatography. Then the various reconstruction algorithms are discussed in five classes: summation, or simple back-projection; convolution, or filtered back-projection; Fourier and other functional transforms; orthogonal function series expansion; and iterative methods. Certain more technical mathematical aspects of image reconstruction are considered from the standpoint of uniqueness, consistency, and stability of solution. The paper concludes by presenting certain open problems. 73 references. (RWR)

Marr, R.B.

1980-04-01T23:59:59.000Z

162

An external dose reconstruction involving a radiological dispersal device  

E-Print Network (OSTI)

emergency situation. In response, the Department of Homeland Security has published Protective Action Guides (DHS 2006) to help minimize these exposures and associated risks. This research attempts to provide some additional radiological exposure knowledge...

Hearnsberger, David Wayne

2007-04-25T23:59:59.000Z

163

Accelerator-based neutron brachytherapy  

Science Journals Connector (OSTI)

The development and evaluation of a new approach to neutronbrachytherapy is described. This approach accelerator-based fast neutronbrachytherapy involves the interstitial or intracavity insertion of a narrow evacuated accelerator beam tube such that its tip containing the neutron-producing target is placed in or near the tumor.Tumorirradiation via brachytherapy should result in a reduction in the healthy tissue complication rate observed when poorly collimated and/or low energy external neutron beam are used for treatment. Use of a variable energy accelerator provides an advantage over isotopesources for neutronbrachytherapy in that the neutron beam can be turned on and off and the neutronenergy spectrum varied for different treatment applications. A prototype accelerator-based fast neutronbrachytherapy device 10 cm long and 6 mm outer diameter has been constructed and evaluated in terms of its dosimetric output treatment time and practical feasibility. The prototype device is a tube-in-tube design with cooling water running between the inner and outer tubes to cool a beryllium target located at the tip of the inner tube. Cooling experiments were performed and coupled with Monte Carlo simulations to determine treatment times as a function of heat load for various neutron-producing reactions. Using the 9 Be (d n) 10 B reaction at E d =1.5 MeV 66 RBE-Gy (12 Gy physical dose) can be delivered to the boundary of a 4.5-cm-diam treatment volume in 8 min at a heat load of 130 W. Other reactions offer similar treatment times at somewhat higher bombarding energies and also show higher potential for dose enhancement with the boron-10 neutron capture reaction due to their softer neutron spectra. Dose distributions in a water phantom were measured with the prototype brachytherapy tube using the dual-ion chamber technique for the 9 Be (d n) 10 B reaction at E d =1.5 MeV. The measurements and simulations agree within uncertainties and demonstrate that fast neutrons contribute more than 90% of the dose to the target volume.

Haijun Song; Jacquelyn C. Yanch; Robert E. Klinkowstein

2002-01-01T23:59:59.000Z

164

Neutron Repulsion  

E-Print Network (OSTI)

Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding how: a.) The Sun generates and releases neutrinos, energy and solar-wind hydrogen and helium; b.) An inhabitable planet formed and life evolved around an ordinary-looking star; c.) Continuous climate change - induced by cyclic changes in gravitational interactions of the Sun's energetic core with planets - has favored survival by adaptation.

Oliver K. Manuel

2011-02-08T23:59:59.000Z

165

Fast-Neutron Handbook  

Science Journals Connector (OSTI)

... FAST neutron physics, in the present context, concerns the study of interactions of atomic nuclei with neutrons ...

J. H. MONTAGUE

1961-06-10T23:59:59.000Z

166

Technical Reports Ultra-low Dose Lung CT Perfusion Regularized by  

E-Print Network (OSTI)

­regularized reconstruction (PSRR) method was proposed to reduce radiation dose and applied to lung perfusion studies. Normal and ultra-low-dose lung computed tomographic perfusion studies were compared in terms of the estimation in radiation dose is achievable using PSRR without compromising quantitative computed tomographic measurements

Virginia Tech

167

Neutron Scattering User Program | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

User Program SHARE Neutron Scattering Can Benefit Your Research Neutron scattering has applications in almost every technical and scientific field, from biology and chemistry to...

168

Neutron Polarization  

Science Journals Connector (OSTI)

Experiments for the determination of the polarization cross section p of iron with monochromatic and non-monochromatic neutrons are described. The absolute value of p as well as its dependence on the neutron velocity is found to be in good agreement with the recent calculations of Steinberger and Wick and also with other experiments. For a complex neutron spectrum originating from a paraffin moderator p¯ is found to be (2.35±0.1)×10-24 cm2 in agreement with previous investigations. It is shown that the larger value of 3.15×10-24 cm2 found by Hughes, Wallace, and Holtzman must be due to spectral differences. The approach of the magnetization of iron towards saturation is also investigated.

J. Fleeman; D. B. Nicodemus; H. H. Staub

1949-12-15T23:59:59.000Z

169

Computational aspects of treatment planning for neutron capture therapy  

E-Print Network (OSTI)

Boron Neutron Capture Therapy (BNCT) is a biochemically targeted form of binary radiation therapy that has the potential to deliver radiation to cancers with cellular dose selectivity. Accurate and efficient treatment ...

Albritton, James Raymond, 1977-

2010-01-01T23:59:59.000Z

170

Commissioning of intensity modulated neutron radiotherapy (IMNRT)  

SciTech Connect

Purpose: Intensity modulated neutron radiotherapy (IMNRT) has been developed using inhouse treatment planning and delivery systems at the Karmanos Cancer Center/Wayne State University Fast Neutron Therapy facility. The process of commissioning IMNRT for clinical use is presented here. Results of commissioning tests are provided including validation measurements using representative patient plans as well as those from the TG-119 test suite. Methods: IMNRT plans were created using the Varian Eclipse optimization algorithm and an inhouse planning system for calculation of neutron dose distributions. Tissue equivalent ionization chambers and an ionization chamber array were used for point dose and planar dose distribution comparisons with calculated values. Validation plans were delivered to water and virtual water phantoms using TG-119 measurement points and evaluation techniques. Photon and neutron doses were evaluated both inside and outside the target volume for a typical IMNRT plan to determine effects of intensity modulation on the photon dose component. Monitor unit linearity and effects of beam current and gantry angle on output were investigated, and an independent validation of neutron dosimetry was obtained. Results: While IMNRT plan quality is superior to conventional fast neutron therapy plans for clinical sites such as prostate and head and neck, it is inferior to photon IMRT for most TG-119 planning goals, particularly for complex cases. This results significantly from current limitations on the number of segments. Measured and calculated doses for 11 representative plans (six prostate/five head and neck) agreed to within -0.8 {+-} 1.4% and 5.0 {+-} 6.0% within and outside the target, respectively. Nearly all (22/24) ion chamber point measurements in the two phantom arrangements were within the respective confidence intervals for the quantity [(measured-planned)/prescription dose] derived in TG-119. Mean differences for all measurements were 0.5% (max = 7.0%) and 1.4% (max = 4.1%) in water and virtual water, respectively. The mean gamma pass rate for all cases was 92.8% (min = 88.6%). These pass rates are lower than typically achieved with photon IMRT, warranting development of a planar dosimetry system designed specifically for IMNRT and/or the improvement of neutron beam modeling in the penumbral region. The fractional photon dose component did not change significantly in a typical IMNRT plan versus a conventional fast neutron therapy plan, and IMNRT delivery is not expected to significantly alter the RBE. All other commissioning results were considered satisfactory for clinical implementation of IMNRT, including the external neutron dose validation, which agreed with the predicted neutron dose to within 1%. Conclusions: IMNRT has been successfully commissioned for clinical use. While current plan quality is inferior to photon IMRT, it is superior to conventional fast neutron therapy. Ion chamber validation results for IMNRT commissioning are also comparable to those typically achieved with photon IMRT. Gamma pass rates for planar dose distributions are lower than typically observed for photon IMRT but may be improved with improved planar dosimetry equipment and beam modeling techniques. In the meantime, patient-specific quality assurance measurements should rely more heavily on point dose measurements with tissue equivalent ionization chambers. No significant technical impediments are anticipated in the clinical implementation of IMNRT as described here.

Burmeister, Jay; Snyder, Michael [Karmanos Cancer Center, Wayne State University School of Medicine, Detroit, Michigan 48201 (United States); Spink, Robyn; Liang Liang; Bossenberger, Todd; Halford, Robert [Karmanos Cancer Center, Detroit, Michigan 48201 (United States); Brandon, John [Michigan State University, East Lansing, Michigan 48201 (United States); Delauter, Jonathan [Wayne State University School of Medicine, Detroit, Michigan 48201 (United States)

2013-02-15T23:59:59.000Z

171

The Neutron  

Science Journals Connector (OSTI)

The writers point out that the postulation of the existence of the "neutron," a combination of an electron and a proton, of small size and low energy would be very useful in explaining a number of atomic and cosmic phenomena. They find that a mathematical treatment based on existing theory leads to indications of such a state but no definite proof.

R. M. Langer and N. Rosen

1931-06-15T23:59:59.000Z

172

NEUTRON ELECTRIC-DIPOLE MOMENT, ULTRACOLD NEUTRONS  

E-Print Network (OSTI)

NEUTRON ELECTRIC-DIPOLE MOMENT, ULTRACOLD NEUTRONS AND POLARIZED 3He R. GOLUB~and Steve K REPORTS (Review Section of Physics Letters) 237, No. 1(1994)1--62. PHYSICS REPORTS North-Holland Neutron electric-dipole moment, ultracold neutrons and polarized 3He R. Goluba and Steve K. Lamoreauxb a

173

Radiation Dose Estimates from  

E-Print Network (OSTI)

Summary: Radiation Dose Estimates from Hanford Radioactive Material Releases to the Air- tantly, what radiation dose people may have received. An independent Technical Steering Panel (TSP, additionalProjectworkcouldresultin revisions of these dose estimates. April 21, 1994 Companion

174

Response of a lithium gadolinium borate scintillator in monoenergetic neutron fields  

Science Journals Connector (OSTI)

......MeV in 18 energy groups...unfolded neutron spectrum using fluence-to-dose...different neutron-producing...particle beam energies to produce...6). The Thermal Neutron Facility...by a 235U fission chamber calibrated...gamma-ray-induced events......

A. M. Williams; P. A. Beeley; N. M. Spyrou

2004-08-01T23:59:59.000Z

175

Neutron reflecting supermirror structure  

DOE Patents (OSTI)

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. 2 figs.

Wood, J.L.

1992-12-01T23:59:59.000Z

176

Neutron reflecting supermirror structure  

DOE Patents (OSTI)

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources.

Wood, James L. (Drayton Plains, MI)

1992-01-01T23:59:59.000Z

177

Neutron Scattering Facilities 1982  

NLE Websites -- All DOE Office Websites (Extended Search)

NEUTRON SOURCES NEUTRON SOURCES Types of Sources U.S. Sources Available for Users Plans for the Future The Neutron Scattering Society of America (NSSA) SNS/ANL School on Neutron and x-Ray Scattering, June 2011 Jim Rhyne Lujan Neutron Scattering Center Los Alamos National Lab. What do we need to do neutron scattering? * Neutron Source - produces neutrons * Diffractometer or Spectrometer - Allows neutrons to interact with sample - Sorts out discrete wavelengths by monochromator (reactor) or by time of flight (pulse source) - Detectors pick up neutrons scattered from sample * Analysis methods to determine material properties * Brain power to interpret results Sources of neutrons for scattering * Nuclear Reactor - Neutrons produced from fission of 235 U - Fission spectrum neutrons

178

Neutron Polarization  

Science Journals Connector (OSTI)

The neutron polarization cross section of iron has been measured as a function of energy from 0.7 to 3.3A by two methods: using the single transmission effect in a block of polycrystalline iron at energies selected by a quartz crystal monochromator; and using a single crystal of magnetized magnetite to analyze the beam emerging from the iron polarizer, the magnetite crystal itself serving as monochromator. The measured values are compared with those of other observers and the theoretically expected values. These are found to agree fairly well within the limits of accuracy of the measurements and existing knowledge of the wave function of the iron 3d shell. The two techniques were used also to determine the average polarization (32 percent) as seen by a 1v detector in a beam of reactor neutrons emerging from a 4-cm thick polarizing block of iron. Problems and techniques associated with the measurement of the average polarization of a continuous spectrum are discussed. A simplified experimental treatment of the problem of beam "hardening" is described. A description is given of the use of the magnetic resonance method in conjunction with a single-crystal magnetite analyzer for the measurement of neutron polarization.

C. P. Stanford; T. E. Stephenson; L. W. Cochran; S. Bernstein

1954-04-15T23:59:59.000Z

179

Neutron Gas  

Science Journals Connector (OSTI)

We assume that the neutron-neutron potential is well-behaved and velocity-dependent. We can then apply perturbation theory to find the energy per particle of a neutron gas, in the range of Fermi wave numbers 0.5

J. S. Levinger and L. M. Simmons

1961-11-01T23:59:59.000Z

180

Internal Dose Estimates from  

E-Print Network (OSTI)

Appendix H Internal Dose Estimates from Global Fallout H-1 #12;Radiation Dose to the Population. 263-MQ-008090 September 30, 2000 H-2 #12;Radiation Dose to the Population of the Continental United Site Part I. Estimates of Dose Lynn R. Anspaugh Lynn R. Anspaugh, Consulting Salt Lake City, UT Report

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


181

Development of a fast neutron therapy beam placement film technique  

E-Print Network (OSTI)

the treatment dose is delivered. It was requested by those radiotherapists who will hopefully utilize the TAMVEC fast-neutron therapy beam, however, that sn "on-line" placement check film be made to doubly insure proper tumor positioning. The research... is achieved, the measured intensity, I(x, E) of the unscat- tered neutrons is given by Equation 1. I(x, E) I (x, E) exp [-u(E)x] Equation 1 0 where I (x, E) = INCIDENT NEUTRON INTENSITY, neutrons/cm /sec 2 p(E) = LINEAR ATTENUATION COEFFICIENT, cm x...

Baron, Robert Layton

2012-06-07T23:59:59.000Z

182

Publications | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Publications SHARE Publications The Neutron Science publications system contains peer-reviewed publications based on research conducted at ORNL's Neutron Science facilities or...

183

Neutron Scattering Facilities  

Science Journals Connector (OSTI)

The past history, present performance and future prospects for neutron scattering facilities will be discussed. Special features of neutron scattering techniques applicable to biological problems will be ... . Th...

D. L. Price

1996-01-01T23:59:59.000Z

184

Calculations of neutron spectra after neutron–neutron scattering  

Science Journals Connector (OSTI)

A direct neutron–neutron scattering length, ann, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of ann will not only help resolve conflicting results of ann by indirect means, but also in comparison to the proton–proton scattering length, app, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrum—Maxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermal–thermal and thermal–epithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.

B E Crawford; S L Stephenson; C R Howell; G E Mitchell; W Tornow; W I Furman; E V Lychagin; A Yu Muzichka; G V Nekhaev; A V Strelkov; E I Sharapov; V N Shvetsov

2004-01-01T23:59:59.000Z

185

Spallation Neutron Source | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Spallation Neutron Source SNS site, Spring 2012 The 80-acre SNS site is located on the east end of the ORNL campus and is about a three-minute drive from her sister neutron...

186

Visualization of a changing dose field.  

SciTech Connect

To help visualize the results of dose modeling for nuclear materials processing opcrations, we have developed an integrated model that uses a simple dosc calculation tool to obtain estimates of the dose field in a complex geomctry and then post-process the data to produce a video of the now time-dependent data. We generate two-dimensional radiation fields within an existing physical cnvironment and then analyze them using three-dimensional visualization techniques. The radiation fields are generated for both neutrons and photons. Standard monoenergetic diffusion theory is used to estimate the neutron dosc fields. The photon dose is estimated using a point-kernel formalism, with photon shielding effects and buildup taken into account. The radiation field dynamics are analyzed by interleaving individual 3D graphic 'snapshots' into a smoothed, lime dependent, video-based display. In-the-room workers are 'seen' in the radiation fields via a graphical, 3D fly-through rendering of the room. Worker dose levels can reveal surprising dependencies on operational source placement, source types, worker alignment, shielding alignments, and indirect operations from external workers.

Helm, T. M (Terry M.); Kornreich, D. E. (Drew E.)

2002-01-01T23:59:59.000Z

187

Neutron insensitive depolymerization of polyacrylamide for californium-252 photon dosimetry  

SciTech Connect

A photon dosimeter based on degradation of polyacrylamide (PAA) in dilute aqueous solution has been found to be insensitive to neutrons from Cf-252, independent of photon energy from 34 keV/sub eff/ to 1.33 MeV, and useful over a dose range of 1 to 100 Gy. Because this dilute polymer solution is virtually 100% water, it is nearly tissue equivalent for photon absorption as well as neutron scatter and attenuation. Radiation response was determined by measuring decreases in viscosity three days after irradiation. The measured response is dose rate independent from 10 to over 300 Gy/h but increases rapidly at lower dose rates. Long-term, radiation-induced viscosity changes were also observed. The many advantages of this tissue equivalent system for photon/neutron dosimetry suggest the need for further studies of the observed over-response at low dose rates.

Moyers, M.F.; Beach, J.L.

1982-09-01T23:59:59.000Z

188

Science | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Science Neutron Science Neutron Scattering Science Neutrons are one of the fundamental particles that make up matter and have properties that make them ideal for certain types of research. In the universe, neutrons are abundant, making up more than half of all visible matter. Neutron scattering provides information about the positions, motions, and magnetic properties of solids. When a beam of neutrons is aimed at a sample, many neutrons will pass through the material. But some will interact directly with atomic nuclei and "bounce" away at an angle, like colliding balls in a game of pool. This behavior is called neutron diffraction, or neutron scattering. Using detectors, scientists can count scattered neutrons, measure their energies and the angles at which they scatter, and map their final position

189

Neutron lifetime measured with stored ultracold neutrons  

Science Journals Connector (OSTI)

The neutron lifetime has been measured by counting the neutrons remaining in a fluid-walled bottle as a function of the duration of storage. Losses of neutrons caused by the wall reflections are eliminated by varying the bottle volume-to-surface ratio. The result obtained is ??=887.6±3 s.

W. Mampe; P. Ageron; C. Bates; J. M. Pendlebury; A. Steyerl

1989-08-07T23:59:59.000Z

190

Neutron-Neutron Quasifree Scattering  

Science Journals Connector (OSTI)

The reaction D(n ,2n)p has been measured at Einc=14.1 MeV, ?n (3)=?n(4)=30?, ?=180?, and the results are compared with the predictions of two separable-potential models. Neutron-proton and proton-proton quasifree scattering from nucleon + deuteron reactions at 14 MeV are also compared with the predictions of the same models. The upper limit of 2 mb/sr2 is determined for the reaction D(n,n?)d.

Ivo Slaus; J. W. Sunier; G. Thompson; J. C. Young; J. W. Verba; D. J. Margaziotis; P. Doherty; R. T. Cahill

1971-03-29T23:59:59.000Z

191

Accelerator shield design of KIPT neutron source facility  

SciTech Connect

Argonne National Laboratory (ANL) of the United States and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the design development of a neutron source facility at KIPT utilizing an electron-accelerator-driven subcritical assembly. Electron beam power is 100 kW, using 100 MeV electrons. The facility is designed to perform basic and applied nuclear research, produce medical isotopes, and train young nuclear specialists. The biological shield of the accelerator building is designed to reduce the biological dose to less than 0.5-mrem/hr during operation. The main source of the biological dose is the photons and the neutrons generated by interactions of leaked electrons from the electron gun and accelerator sections with the surrounding concrete and accelerator materials. The Monte Carlo code MCNPX serves as the calculation tool for the shield design, due to its capability to transport electrons, photons, and neutrons coupled problems. The direct photon dose can be tallied by MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is less than 0.01 neutron per electron. This causes difficulties for Monte Carlo analyses and consumes tremendous computation time for tallying with acceptable statistics the neutron dose outside the shield boundary. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were developed for the study. The generated neutrons are banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron and secondary photon doses. The weight windows variance reduction technique is utilized for both neutron and photon dose calculations. Two shielding materials, i.e., heavy concrete and ordinary concrete, were considered for the shield design. The main goal is to maintain the total dose outside the shield boundary at less than 0.5-mrem/hr. The shield configuration and parameters of the accelerator building have been determined and are presented in this paper. (authors)

Zhong, Z.; Gohar, Y. [Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States)

2013-07-01T23:59:59.000Z

192

Neutron reflecting supermirror structure  

DOE Patents (OSTI)

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. One layer of each set of bilayers consist of titanium, and the second layer of each set of bilayers consist of an alloy of nickel with carbon interstitially present in the nickel alloy.

Wood, James L. (Drayton Plains, MI)

1992-01-01T23:59:59.000Z

193

Direct Measurement of Neutron?Neutron Scattering  

Science Journals Connector (OSTI)

In order to resolve long?standing discrepancies in indirect measurements of the neutron?neutron scattering length ann and contribute to solving the problem of the charge symmetry of the nuclear force the collaboration DIANNA (Direct Investigation of ann Association) plans to measure the neutron?neutron scattering cross section ? nn . The key issue of our approach is the use of the through?channel in the Russia reactor YAGUAR with a peak neutron flux of 1018 /cm2/s. The proposed experimental setup is described. Results of calculations are presented to connect ? nn with the nn?collision detector count rate and the neutron flux density in the reactor channel. Measurements of the thermal neutron fields inside polyethylene converters show excellent prospects for the realization of the direct nn?experiment.

E. I. Sharapov; C. D. Bowman; B. E. Crawford; W. I. Furman; C. R. Howell; B. G. Levakov; V. I. Litvin; W. I. Lychagin; A. E. Lyzhin; E. P. Magda; G. E. Mitchell; G. V. Muzichka; G. V. Nekhaev; Yu. V. Safronov; V. N. Shvetsov; S. L. Stephenson; A. V. Strelkov; W. Tornow

2003-01-01T23:59:59.000Z

194

Activation of Soil and Chemical Reagents Exposed to the Neutrons Released by the JCO Criticality Accident in Tokai-mura  

Science Journals Connector (OSTI)

......hours) of fission neutrons to the environment...release of fission products. To evaluate the neutron doses to residents...of neutron-induced radionuclides...the apparent thermal S56 Y. MURATA...fluence and its energy spectrum. By using......

Yoshimasa Murata; Toshiharu Muroyama; Yoshiko Kawabata; Masayoshi Yamamoto; Kazuhisa Komura

2001-09-01T23:59:59.000Z

195

Radiation dose reduction and image enhancement in biological imaging through equally-sloped tomography  

E-Print Network (OSTI)

Iterative reconstruction algorithm Radiation dose reduction Image enhancement Computed tomography a b s t r-dose data acquisi- tion schemes have made it possible to record multiple projections quickly without-energy electrons (Henderson, 1995), which limits the number of projections that can be acquired. Furthermore

Miao, Jianwei "John"

196

Neutron issues in the JANUS mouse program  

SciTech Connect

Over the last 25 years, the JANUS program in the Biological and Medical Research Division at Argonne National Laboratory (ANL) has compiled a database on the response of both sexes of an F{sub 1} hybrid mouse, the B6CF{sub 1} (C57BL/6 x BALB/c), to external whole- body irradiation by {sup 60}Co {gamma}-rays and fission neutrons. Three basic patterns of exposure for both neutrons and {gamma}-rays have been investigated: single exposures, 24 equal once-weekly exposures, and 60 equal once-weekly exposures. All irradiations were terminated at predetermined total doses, with dose calculated in centigrays at the midline of the mouse. Three endpoints will be discussed in this paper: (1) life shortening, (2) a point estimate for cumulative mortality, and (3) the hazard function. Life shortening is used as an analysis endpoint because it summarizes, in a single index, the integrated effect of all injuries accumulated by an organism. Histopathological analyses of the mice used in the ANL studies have indicated that 85% of the deaths were caused by neoplasms. Connective tissue tumors were the dominant tumor in the B6CF{sub 1} mouse, with tumors of lymphoreticular origin accounting for approximately 80% of this class. The latter two endpoints will therefore be used to describe the life table experience of mice dying from the lymphoreticular class of tumors. Dose-response models will be applied to the three endpoints in order to describe the response function for neutron exposures, evaluate the effect of dose range and pattern of exposure on the response function for neutrons, and provide a set of neutron relative biological effectiveness (RBE) values of the ANL database. 25 refs.

Carnes, B.A.; Grahn, D.

1990-01-01T23:59:59.000Z

197

Neutron-Mirror-Neutron Oscillations in a Trap  

E-Print Network (OSTI)

We calculate the rate of neutron-mirror-neutron oscillations for ultracold neutrons trapped in a storage vessel. Recent experimental bounds on the oscillation time are discussed.

B. Kerbikov; O. Lychkovskiy

2008-04-03T23:59:59.000Z

198

Neutron–mirror-neutron oscillations in a trap  

Science Journals Connector (OSTI)

We calculate the rate of neutron–mirror-neutron oscillations for ultracold neutrons trapped in a storage vessel. Recent experimental bounds on the oscillation time are discussed.

B. Kerbikov and O. Lychkovskiy

2008-06-27T23:59:59.000Z

199

Manuel Lujan Jr. Neutron Scattering Center Los Alamos Neutron...  

NLE Websites -- All DOE Office Websites (Extended Search)

2013 LANSCE School on Neutron Scattering Geosciences & Materials in Extreme Environments Manuel Lujan Jr. Neutron Scattering Center Los Alamos Neutron Science Center Los Alamos...

200

Neutron crystallography aids drug design  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron crystallography aids drug design Neutron crystallography aids drug design Researchers have used neutron crystallography for the first time to determine the structure of a...

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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201

Los Alamos Neutron Science Center  

NLE Websites -- All DOE Office Websites (Extended Search)

LINAC Outreach Affiliations Visiting LANSCE Facilities Isotope Production Facility Lujan Neutron Scattering Center MaRIE Proton Radiography Ultracold Neutrons Weapons Neutron...

202

Neutron range spectrometer  

DOE Patents (OSTI)

A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are collimnated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. The computer solves the following equation in the analysis: ##EQU1## where: N(x).DELTA.x=the number of neutron interactions measured between a position x and x+.DELTA.x, A.sub.i (E.sub.i).DELTA.E.sub.i =the number of incident neutrons with energy between E.sub.i and E.sub.i +.DELTA.E.sub.i, and C=C(E.sub.i)=N .sigma.(E.sub.i) where N=the number density of absorbing atoms in the position sensitive counter means and .sigma. (E.sub.i)=the average cross section of the absorbing interaction between E.sub.i and E.sub.i +.DELTA.E.sub.i.

Manglos, Stephen H. (East Syracuse, NY)

1989-06-06T23:59:59.000Z

203

Neutron Generator as a Neutron Source for BNCT  

Science Journals Connector (OSTI)

A neutron generator was investigated for a neutron source for BNCT. Neutron generators have some obvious advantages over nuclear reactors for this purpose. The neutron source is the reaction D(d,n)3He. Moderation...

Gad Shani; Lev Tsvang; Semion Rozin; Michael Quastel

1996-01-01T23:59:59.000Z

204

Neutron producing target for accelerator based neutron source for  

E-Print Network (OSTI)

247 Neutron producing target for accelerator based neutron source for NCT V. Belov1 , S. Fadeev1, Russia Summary Neutron producing targets for novel accelerator based neutron source [1, 2] are presented Neutron producing target is one of the main elements of proposed accelerator based facility for neutron

Taskaev, Sergey Yur'evich

205

Doses to patients from photoneutrons emitted in a medical linear accelerator  

Science Journals Connector (OSTI)

......Center, Khartoum, PO Box 846, Sudan 2 Faculty of Science and Technology...Khartoum, PO Box 12702, Sudan 3 ICTP, Strada Costiera 11...Khartoum, Khartoum, PO Box 321, Sudan This study of doses to patients...sizes and they noticed that the thermal neutron dose equivalent contributes......

M. K. Saeed; O. Moustafa; O. A. Yasin; C. Tuniz; F. I. Habbani

2009-02-01T23:59:59.000Z

206

Neutron interactions with biological tissue. Final report  

SciTech Connect

This program was aimed at creating a quantitative physical description, at the micrometer and nanometer levels, of the physical interactions of neutrons with tissue through the ejected secondary charged particles. The authors used theoretical calculations whose input includes neutron cross section data; range, stopping power, ion yield, and straggling information; and geometrical properties. Outputs are initial and slowing-down spectra of charged particles, kerma factors, average values of quality factors, microdosimetric spectra, and integral microdosimetric parameters such as {bar y}{sub F}, {bar y}{sub D}, y{sup *}. Since it has become apparent that nanometer site sizes are also relevant to radiobiological effects, the calculations of event size spectra and their parameters were extended to these smaller diameters. This information is basic to radiological physics, radiation biology, radiation protection of workers, and standards for neutron dose measurement.

NONE

1998-02-17T23:59:59.000Z

207

Reconstruction on Si(100) surfaces  

Science Journals Connector (OSTI)

We have observed several reconstructions on a Si(100) surface with different annealing procedures. The observed reconstructed phases are the coexistence of the (2×2) phase and the (2×8) phase after high-temperature (?950 K) annealing followed by quenching, and the half-order streak with the presence of the (2×1) phase after low-temperature (?950 K) annealing. The phase transition from the metastable (2×2) and (2×8) phases to the stable half-order streak is reversible upon annealing temperature and cooling rate. The distribution of kinks and missing dimer defects is expected to be the main cause of these reconstructions.

Young Joo Lee; Sehun Kim; Chi-Sun Hwang; C. Lee; Chanyong Hwang

1994-10-15T23:59:59.000Z

208

Measurements of fast neutrons by bubble detectors  

SciTech Connect

Neutron bubble detectors have been studied using Am-Be and D-D neuron sources, which give limited energy information. The Bubble Detector Spectrometer (BDS) have six different energy thresholds ranging from 10 KeV to 10 Mev. The number of bubbles obtained in each measurement is related to the dose (standardized response R) equivalent neutrons through sensitivity (b / {mu}Sv) and also with the neutron flux (neutrons per unit area) through a relationship that provided by the manufacturer. Bubble detectors were used with six different answers (0.11 b/ {mu}Sv, 0093 b/{mu}Sv, 0.14 b/{mu}Sv, 0.17 b/{mu}Sv, 0051 b/{mu}Sv). To test the response of the detectors (BDS) radiate a set of six of them with different energy threshold, with a source of Am-Be, placing them at a distance of one meter from it for a few minutes. Also, exposed to dense plasma focus Fuego Nuevo II (FN-II FPD) of ICN-UNAM, apparatus which produces fusion plasma, generating neutrons by nuclear reactions of neutrons whose energy emitting is 2.45 MeV. In this case the detectors were placed at a distance of 50 cm from the pinch at 90 Degree-Sign this was done for a certain number of shots. In both cases, the standard response is reported (Dose in {mu}Sv) for each of the six detectors representing an energy range, this response is given by the expression R{sub i}= B{sub i} / S{sub i} where B{sub i} is the number of bubbles formed in each and the detector sensitivity (S{sub i}) is given for each detector in (b / {mu}Sv). Also, reported for both cases, the detected neutron flux (n cm{sup -2}), by a given ratio and the response involves both standardized R, as the average cross section sigma. The results obtained have been compared with the spectrum of Am-Be source. From these measurements it can be concluded that with a combination of bubble detectors, with different responses is possible to measure the equivalent dose in a range of 10 to 100 {mu}Sv fields mixed neutron and gamma, and pulsed generated fusion devices.

Castillo, F.; Martinez, H. [Laboratorio de Espectroscopia, Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62251, Cuernavaca Morelos (Mexico); Leal, B. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, 04510, Ciudad Universitaria, Mexico D. F. (Mexico); Rangel, J. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, 04510, Ciudad Universitaria, Mexico D. F (Mexico); Reyes, P. G. [Facultad de Ciencias, Universidad Autonoma del Estado de Mexico, Instituto Literario 100, Col. Centro, 50000, Toluca Estado de Mexico (Mexico)

2013-07-03T23:59:59.000Z

209

Treatment Planning for Accelerator-Based Boron Neutron Capture Therapy  

SciTech Connect

Glioblastoma multiforme and metastatic melanoma are frequent brain tumors in adults and presently still incurable diseases. Boron Neutron Capture Therapy (BNCT) is a promising alternative for this kind of pathologies. Accelerators have been proposed for BNCT as a way to circumvent the problem of siting reactors in hospitals and for their relative simplicity and lower cost among other advantages. Considerable effort is going into the development of accelerator-based BNCT neutron sources in Argentina. Epithermal neutron beams will be produced through appropriate proton-induced nuclear reactions and optimized beam shaping assemblies. Using these sources, computational dose distributions were evaluated in a real patient with diagnosed glioblastoma treated with BNCT. The simulated irradiation was delivered in order to optimize dose to the tumors within the normal tissue constraints. Using Monte Carlo radiation transport calculations, dose distributions were generated for brain, skin and tumor. Also, the dosimetry was studied by computing cumulative dose-volume histograms for volumes of interest. The results suggest acceptable skin average dose and a significant dose delivered to tumor with low average whole brain dose for irradiation times less than 60 minutes, indicating a good performance of an accelerator-based BNCT treatment.

Herrera, Maria S.; Gonzalez, Sara J. [Comision National de Energia Atomica and CONICET, Buenos Aires (Argentina); Minsky, Daniel M.; Kreiner, Andres J. [Comision National de Energia Atomica and CONICET, Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, UNSAM, Buenos Aires (Argentina)

2010-08-04T23:59:59.000Z

210

Instruments | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

NScD Careers NScD Careers Supporting Organizations Neutron Science Home | Science & Discovery | Neutron Science | Instruments SHARE Instruments at SNS and HFIR SNS Instrument Name HFIR Instrument Name 1B NOMAD - Nanoscale-Ordered Materials Diffractometer CG-1 Development Beam Line 2 BASIS - Backscattering Spectrometer CG-1D IMAGING - Neutron Imaging Prototype Facility 3 SNAP - Spallation Neutrons and Pressure Diffractometer CG-2 GP-SANS - General-Purpose Small-Angle Neutron Scattering Diffractometer 4A MR - Magnetism Reflectometer CG-3 Bio-SANS - Biological Small-Angle Neutron Scattering Instrument 4B LR - Liquids Reflectometer CG-4C CTAX - Cold Neutron Triple-Axis Spectrometer 5 CNCS - Cold Neutron Chopper Spectrometer HB-1 PTAX - Polarized Triple-Axis Spectrometer

211

Pulsed-neutron monochromator  

DOE Patents (OSTI)

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The waves are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

Mook, H.A. Jr.

1984-01-01T23:59:59.000Z

212

The Harwell Neutron Project  

Science Journals Connector (OSTI)

... 2 cm. thick, placed on three sides of the neutron booster. A layer of boron-10 metal placed between these tanks and the uranium-235 core prevents return of slow neutrons ...

M. J. POOLE; E. R. RAE

1960-01-30T23:59:59.000Z

213

Pulsed-neutron monochromator  

DOE Patents (OSTI)

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The wave are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

Mook, Jr., Herbert A. (Oak Ridge, TN)

1985-01-01T23:59:59.000Z

214

Neutrons - 88-Inch Cyclotron  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutrons Neutron beams are available at the 88-Inch Cyclotron. Available energies range of from 8 to 30 MeV, with fluxes of up to 1E8 neutronscm2sec. For more information,...

215

Thermal Neutron Scattering  

Science Journals Connector (OSTI)

... of its title. It is not for the nuclear physicist, nor even for the neutron physicist, but for the student of solids and liquids. "Thermal ... physicist, but for the student of solids and liquids. "Thermal neutron ...

G. E. BACON

1968-11-09T23:59:59.000Z

216

Neutron activation analysis  

Science Journals Connector (OSTI)

Neutron activation analysis (NAA) is an that relies on the measurement of ?-rays emitted from a sample that was irradiated by neutrons. The rate at which ?-rays are emitted from an element in a sample is dir...

James R. Budahn

1998-01-01T23:59:59.000Z

217

Ultrafast neutron detector  

DOE Patents (OSTI)

A neutron detector of very high temporal resolution is described. It may be used to measure distributions of neutrons produced by fusion reactions that persist for times as short as about 50 picoseconds.

Wang, C.L.

1985-06-19T23:59:59.000Z

218

Neutron dosimetry in boron neutron capture therapy using aqueous solutions of lithium acetate  

Science Journals Connector (OSTI)

This paper presents the development of a dosimetry method, based on liquid scintillation (LS) counting of the tritium that is produced in aqueous solutions of lithium acetate, for the determination of the boron and nitrogen absorbed doses in-phantom in BNCT. The dosimeter is passive, integrating, approximately tissue equivalent, and insensitive to gamma rays and the elastic scattering of fast neutrons. The dosimetry method exhibits a response which is proportional to the boron and nitrogen absorbed doses and which can be calibrated to NIST standard solutions of water spiked with tritium. For 0.2 g of lithium acetate dissolved in a milliliter of water, the measured sensitivity is (1.73±0.04)×10?9 cpm per unit of thermal neutron fluence (in neutrons/cm2). For the LS analyzer that was used, the background signal was 12.84±0.02 cpm, yielding a thermal neutron fluence threshold for this detection method of approximately 7×109 neutrons/cm2.

L.J. Rakovan; T.E. Blue; A.L. Vest

1998-01-01T23:59:59.000Z

219

ACDOS2: AN IMPROVED NEUTRON-INDUCED DOSE RATE CODE  

E-Print Network (OSTI)

o! *cr t i n i «,5iiE-*t . ;aoc*02 icnn;i .ni'. -n fJ-EIHIPSM'M . -^'.vT^nj 2Vlf6l . *aoc»oi il % I f 7 I P .J^BT'Q?

Lagache, J-C.

2010-01-01T23:59:59.000Z

220

ACDOS2: AN IMPROVED NEUTRON-INDUCED DOSE RATE CODE  

E-Print Network (OSTI)

of copper. From the "chart of nuclides', 9th edition, 1966:molyb­ denum from the "chart of nuclides" 9th edition, 1966,

Lagache, J-C.

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Neutron computed tomography  

E-Print Network (OSTI)

to make the Donner Algorithms run. TABLE OF CONTEliiTS CHAPTF. . R I NEI. TRON RADIOGRAPHY . I. 1 Background . I. 2 Theory . l. 3 Neutron Beam Characterization I. 4 Image Detectors . COMPI'TED TOMOGRAPHY . Il I Background . II. 2 Notation II. 3... data which is generated by rays traveling (and being attenuated) in straight lines. However in neutron radiography, what is measured is, to most extents, the levels of neutrons which are not attenuated. Neutrons are particles. They scatter...

Russell, Clifford Marlow

2012-06-07T23:59:59.000Z

222

Neutron scattering and ribosomes  

Science Journals Connector (OSTI)

... the complexity of intra-ribosomal interactions. This is however by no means the case with neutron ...neutronscattering ...

Richard Brimacombe

1977-06-23T23:59:59.000Z

223

Development of a gamma ray telescope for online synovial dosimetry in boron neutron capture synovectomy  

E-Print Network (OSTI)

Boron Neutron Capture Synovectomy (BNCS) is a novel application of the ¹?B(n,?) reaction for potential treatment of rheumatoid arthritis. During BNCS clinical trials, real-time knowledge of boron dose delivered to the ...

Jiang, Hongyu, 1971-

2003-01-01T23:59:59.000Z

224

The investigation of spices by use of instrumental neutron activation analysis  

E-Print Network (OSTI)

contaminants. For this research, instrumental neutron-activation analysis (INAA) was used to determine the activities of U-235 fission products in common spices. Using this information, the concentrations of natural uranium in these spices and the doses...

Wise, Jatara Rob

2008-10-10T23:59:59.000Z

225

More about neutron - mirror neutron oscillation  

E-Print Network (OSTI)

It was pointed out recently that oscillation of the neutron $n$ into mirror neutron $n'$, a sterile twin of the neutron with exactly the same mass, could be a very fast process with the the baryon number violation, even faster than the neutron decay itself. This process is sensitive to the magnetic fields and it could be observed by comparing the neutron lose rates in the UCN storage chambers for different magnetic backgrounds. We calculate the probability of $n-n'$ oscillation in the case when a mirror magnetic field $\\vec{B}'$ is non-zero and show that in this case it can be suppressed or resonantly enhanced by applying the ordinary magnetic field $\\vec{B}$, depending on its strength and on its orientation with respect to $\\vec{B}'$. The recent experimental data, under this hypothesis, still allow the $n-n'$ oscillation time order 1 s or even smaller. Moreover, they indicate that the neutron losses are sensitive to the orientation of the magnetic field. %at about $3\\sigma$ level. If these hints will be confirmed in the future experiments, this would point to the presence of the mirror magnetic field on the Earth of the order of 0.1 G, or some equivalent spin-dependent force of the other origin that makes a difference between the neutron and mirror neutron states.

Zurab Berezhiani

2008-04-13T23:59:59.000Z

226

Neutron removal cross section as a measure of neutron skin  

Science Journals Connector (OSTI)

We study the relation between neutron removal cross section (?-N) and neutron skin thickness for finite neutron-rich nuclei using the statistical abrasion ablation model. Different sizes of neutron skin are obtained by adjusting the diffuseness parameter of neutrons in the Fermi distribution. It is demonstrated that there is a good linear correlation between ?-N and the neutron skin thickness for neutron-rich nuclei. Further analysis suggests that the relative increase of neutron removal cross section could be used as a quantitative measure for neutron skin thickness in neutron-rich nuclei.

D. Q. Fang (???); Y. G. Ma (???); X. Z. Cai (???); W. D. Tian (???); H. W. Wang (???)

2010-04-07T23:59:59.000Z

227

Carrier doping into boron nanobelts by neutron transmutation  

SciTech Connect

We report the effects of a neutron-capture reaction of isotope {sup 10}B on the structure and electrical transport of {sup 10}B-enriched single-crystalline boron nanobelts. Partial amorphization, particularly at the surface of the nanobelt, was observed after thermal neutron irradiation with a dose of 2x10{sup 19} cm{sup -2}. Carrier doping into the nanobelts by neutron transmutation is expected after postannealing. The change in conductance is discussed based on the distribution of localized states in the band gap of {alpha}-tetragonal boron.

Kirihara, Kazuhiro; Shimizu, Yoshiki; Sasaki, Takeshi; Koshizaki, Naoto [Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565 (Japan); Yamada, Yoichi [Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Esaka, Fumitaka [Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Yamamoto, Hiroyuki; Shamoto, Shin-ichi [Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Kimura, Kaoru [Department of Advanced Materials Science, The University of Tokyo, Kashiwa, Chiba 277-8561 (Japan)

2010-11-22T23:59:59.000Z

228

External Dose Estimates from  

E-Print Network (OSTI)

Appendix G External Dose Estimates from Global Fallout G-1 #12;External Radiation Exposure-MQ-003539 March 15, 2000 G-2 #12;Abstract This report provides estimates of the external radiation-62. Estimates are given on a county by county basis for each month from 1953-1972. The average population dose

229

External Dose Estimates from  

E-Print Network (OSTI)

Appendix E External Dose Estimates from NTS Fallout E-1 #12;External Radiation Exposure. 1, 1999) E-2 #12;Abstract This report provides estimates of the external radiation exposure of this report to: "Prepare crude estimates of the doses from external irradiation received by the American

230

The neutron warhead decision  

Science Journals Connector (OSTI)

The neutron warhead decision ... Nuclear war moved a step closer last week with the U.S.'s decision to move ahead with production of so-called neutron warheads for use on short-range missiles and in artillery shells. ... And neutron weapons would be almost as effective on ... ...

MICHAEL HEYLIN

1981-08-17T23:59:59.000Z

231

Digital Pygmalion Accurate 3D reconstruction  

E-Print Network (OSTI)

;Overview · Accurate 3D reconstruction from uncalibrated cameras (motion and lighting) · Multi-view stereo - 3D shape from uncalibrated images (review) · Multi-view photometric stereo with uncalibrated lights reconstruction of streets #12;Trumpington Street Data #12;3D reconstruction #12;Reconstruction texture mapped #12

Cipolla, Roberto

232

Principles of neutron reflection  

SciTech Connect

Neutron reflection is perhaps the most developed branch of slow neutrons optics, which in itself is a direct consequence of the undulatory nature of the neutron. After reviewing the basic types of interactions (nuclear and magnetic) between neutrons and matter, the formalism is introduced to calculate the reflectivity from a sample composed of stacked flat layers and, inversely, to calculate the stacking from reflectivity measurements. Finally, a brief survey of the applications of neutron reflection is given, both in technology and in fundamental research. 32 refs., 6 figs.

Felcher, G.P.

1988-08-01T23:59:59.000Z

233

On neutron numbers and atomic masses  

Science Journals Connector (OSTI)

On neutron numbers and atomic masses ... Assigning neutron numbers, correct neutron numbers, and atomic masses and nucleon numbers. ...

R. Heyrovská

1992-01-01T23:59:59.000Z

234

Spallation Neutron Source, SNS  

NLE Websites -- All DOE Office Websites (Extended Search)

Spallation Neutron Source Spallation Neutron Source Providing the most intense pulsed neutron beams in the world... Accumulator Ring Commissioning Latest Step for Spallation Neutron Source The Spallation Neutron Source, located at Oak Ridge National Laboratory, has passed another milestone on the way to completion this year--the commissioning of the proton accumulator ring. Brookhaven led the design and construction of the accumulator ring, which will allow an order of magnitude more beam power than any other facility in the world. The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built in Oak Ridge, Tennessee, by the U.S. Department of Energy. The figure on the right shows a schematic of the accumulator ring and transport beam lines that are being designed and built by Brookhaven

235

The Neutron Lifetime  

E-Print Network (OSTI)

The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and the simplest example of nuclear beta decay. The nucleon vector and axial vector weak coupling constants G_V and G_A determine the neutron lifetime as well as the strengths of weak interaction processes involving free neutrons and protons that are important in astrophysics, cosmology, solar physics and neutrino detection. In combination with a neutron decay angular correlation measurement, the neutron lifetime can be used to determine the first element of the CKM matrix Vud. Unfortunately the two main experimental methods for measuring the neutron lifetime currently disagree by almost 4 sigma. I will present a brief review of the status of the neutron lifetime and prospects for the future.

Wietfeldt, F E

2014-01-01T23:59:59.000Z

236

The Neutron Lifetime  

E-Print Network (OSTI)

The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and the simplest example of nuclear beta decay. The nucleon vector and axial vector weak coupling constants G_V and G_A determine the neutron lifetime as well as the strengths of weak interaction processes involving free neutrons and protons that are important in astrophysics, cosmology, solar physics and neutrino detection. In combination with a neutron decay angular correlation measurement, the neutron lifetime can be used to determine the first element of the CKM matrix Vud. Unfortunately the two main experimental methods for measuring the neutron lifetime currently disagree by almost 4 sigma. I will present a brief review of the status of the neutron lifetime and prospects for the future.

F. E. Wietfeldt

2014-11-13T23:59:59.000Z

237

Neutron radiation can activate K-ras via a point mutation in codon 146 and induces a different spectrum of ras mutations than does gamma radiation.  

Science Journals Connector (OSTI)

research-article Research Article Neutron radiation can activate K-ras via a point...School of Medicine, New York 10016. Neutron radiation is known to produce tumors in...RF/J mice by a single acute dose of neutron irradiation. Activated ras genes were...

S R Sloan; E W Newcomb; A Pellicer

1990-01-01T23:59:59.000Z

238

Imaging and Neutrons - IAN 2006 - Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

SNS Home Saturday, January 11, 2014 SNS Home Saturday, January 11, 2014 Go IAN 2006 Imaging and Neutrons 2006 October 23-25, 2006 Iran Thomas Auditorium Central Laboratory and Office Building Spallation Neutron Source Oak Ridge National Laboratory, Oak Ridge, TN Who Should Attend Synopsis Goals and Expected Outcomes Application Areas Techniques International Advisory Committee Local Organizing Committee Agenda with Presentations NEW Confirmed Speakers Frequently Asked Questions - FAQ Satellite Workshop - Progress in Electron Volt Neutron Spectroscopy eV Worshop Agenda presentations NEW Lodging, Transportation, Bus Schedule Location Directions and Map Registration CLOSED Abstracts, Posters, Contributed Talks Scholarships Sponsors Vendors May Attend Relevant Reports Important Dates Weather Attractions

239

Boron thermal/epithermal neutron capture therapy  

SciTech Connect

The development of various particle beams for radiotherapy represents an attempt to improve dose distribution, and to provide high LET radiations which are less sensitive to ambient physical and radiobiological factors such as oxygen tension, cell cycle, and dose rate. In general, a compromise is necessary as effective RBE is reduced in order to spread the dose distribution over the anticipated tumor volume. The approach of delivering stable non-toxic isotopes to tumor, and then activating these atoms subsequently via an external radiation beam has mator advantages; problems associated with high uptake of these isotopes in competing cell pools are obviated, and the general tumor volume can be included in the treatment field of the activating beam. As long as the normal tissues supporting tumor show a low uptake of the isotope to be activated, and as long as the range of the reaction products is short, dose will be restricted to tumor, with a consequent high therapeutic ratio. Neutron Capture Therapy (NCT) is generally carried out by activating boron-10 with low energy neutrons. The range of the high LET, low OER particles from the /sup 10/B(n, ..cap alpha..)/sup 7/Li reaction is approx. 10..mu.., or one cell diameter, a situation that is optimal for cell killing. Significant advantages may be gained by using the NCT procedure in conjunction with improved tissue penetration provided with epithermal or filtered beams, and new compounds showing physiological binding to tumor.

Fairchild, R.G.

1982-01-01T23:59:59.000Z

240

Characterization of the Neutron Fields in the Lawrence Livermore National Laboratory (LLNL) Radiation Calibration Laboratory Low Scatter Calibration Facility  

SciTech Connect

In June 2007, the Department of Energy (DOE) revised its rule on Occupational Radiation Protection, Part 10 CFR 835. A significant aspect of the revision was the adoption of the recommendations outlined in International Commission on Radiological Protection (ICRP) Report 60 (ICRP-60), including new radiation weighting factors for neutrons, updated internal dosimetric models, and dose terms consistent with the newer ICRP recommendations. ICRP-60 uses the quantities defined by the International Commission on Radiation Units and Measurements (ICRU) for personnel and area monitoring including the ambient dose equivalent H*(d). A Joint Task Group of ICRU and ICRP has developed various fluence-to-dose conversion coefficients which are published in ICRP-74 for both protection and operational quantities. In February 2008, Lawrence Livermore National Laboratory (LLNL) replaced its old pneumatic transport neutron irradiation system in the Radiation Calibration Laboratory (RCL) Low Scatter Calibration Facility (B255, Room 183A) with a Hopewell Designs irradiator model N40. The exposure tube for the Hopewell system is located close to, but not in exactly the same position as the exposure tube for the pneumatic system. Additionally, the sources for the Hopewell system are stored in Room 183A where, prior to the change, they were stored in a separate room (Room 183C). The new source configuration and revision of the 10 CFR 835 radiation weighting factors necessitate a re-evaluation of the neutron dose rates in B255 Room 183A. This report deals only with the changes in the operational quantities ambient dose equivalent and ambient dose rate equivalent for neutrons as a result of the implementation of the revised 10 CFR 835. In the report, the terms 'neutron dose' and 'neutron dose rate' will be used for convenience for ambient neutron dose equivalent and ambient neutron dose rate equivalent unless otherwise stated.

Radev, R

2009-09-04T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Characteristics of the Neutron Irradiation Facilities of the PSI Calibration Laboratory  

SciTech Connect

The neutron radiation fields of the Calibration Laboratory at Paul Scherrer Institute (PSI) are traceable to the national standards of the Physikalisch-Technische Bundesanstalt (PTB) in Germany. A Berthold LB6411 neutron dose rate meter for neutron radiation is used as a secondary standard. Recently, a thorough characterization of the neutron irradiation fields of the {sup 241}Am-Be and {sup 252}Cf sources by means of reference measurements and a detailed MCNPX simulation of the irradiation facility has been initiated. In this work, the characteristics of the neutron radiation fields are summarized and presented together with model equations and an uncertainty analysis. MCNPX results are shown for the {sup 241}Am-Be source. A comparison of measured and simulated data shows an excellent agreement. From the simulation, valuable information about the neutron fields like the contribution of scattered neutrons in the fields and the energy spectra could be obtained.

Hoedlmoser, H.; Schuler, Ch.; Butterweck, G.; Mayer, S. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)

2011-12-13T23:59:59.000Z

242

Estimation of internal radiation dose from both immediate releases and continued  

Science Journals Connector (OSTI)

A brief description is provided of the basic concepts related to 'internal dose' and how it differs from doses that result from radioactive materials and direct radiation outside of the body. The principles of radiation dose reconstruction, as applied to both internal and external doses, are discussed on the basis of a recent publication prepared by the US National Council on Radiation Protection and Measurements. Finally, ideas are introduced related to residual radioactive contamination in the environment that has resulted from the releases from damaged reactors and also to the management of wastes that may be generated in both regional cleanup and decommissioning of the Fukushima nuclear power plant.

Bruce Napier

2012-01-01T23:59:59.000Z

243

Neutron imaging of alkali metal heat pipes  

SciTech Connect

High-temperature heat pipes are two-phase, capillary driven heat transfer devices capable of passively providing high thermal fluxes. Such a device using a liquid-metal coolant can be used as a solution for successful thermal management on hypersonic flight vehicles. Imaging of the liquid-metal coolant inside will provide valuable information in characterizing the detailed heat and mass transport. Neutron imaging possesses an inherent advantage from the fact that neutrons penetrate the heat pipe metal walls with very little attenuation, but are significantly attenuated by the liquid metal contained inside. Using the BT-2 beam line at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, preliminary efforts have been conducted on a nickel-sodium heat pipe. The contrast between the attenuated beam and the background is calculated to be approximately 3%. This low contrast requires sacrifice in spatial or temporal resolution so efforts have since been concentrated on lithium (Li) which has a substantially larger neutron attenuation cross section. Using the CG-1D beam line at the High Flux Isotope Reactor (HFIR) of Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, the first neutron images of high-temperature molybdenum (Mo)-Li heat pipes have been achieved. The relatively high neutron cross section of Li allows for the visualization of the Li working fluid inside the heat pipes. The evaporator region of a gravity assisted cylindrical heat pipe prototype 25 cm long was imaged from start-up to steady state operation up to approximately 900 C. In each corner of the square bore inside, the capillary action raises the Li meniscus above the bulk Li pool in the evaporator region. As the operational temperature changes, the meniscus shapes and the bulk meniscus height also changes. Furthermore, a three-dimensional tomographic image is also reconstructed from the total of 128 projection images taken 1.4o apart in which the Li had already cooled and solidified.

Kihm, Ken [University of Tennessee, Knoxville (UTK); Kirchoff, Eric [University of Tennessee, Knoxville (UTK); Golden, Matt [University of Tennessee, Knoxville (UTK); Rosenfeld, J. [Thermacore Inc.; Rawal, S. [Lockheed Martin Space Systems Company; Pratt, D. [United States Air Force Research Laboratory, Wright-Patterson Air Force Base; Bilheux, Hassina Z [ORNL; Walker, Lakeisha MH [ORNL; Voisin, Sophie [ORNL; Hussey, Dan [NIST Center for Neutron Research (NCRN), Gaithersburg, MD

2013-01-01T23:59:59.000Z

244

Cold neutron research facility at the Budapest Neutron Centre  

Science Journals Connector (OSTI)

The new cold neutron research facility has been routinely operated at the Budapest Neutron Centre (BNC) since February 2001. This ... of equipment consists of a liquid hydrogen cold neutron source, an optimised s...

L. Rosta

2002-12-01T23:59:59.000Z

245

Measurement of Thermal Neutron Flux in Photo-Neutron Source  

Science Journals Connector (OSTI)

The Photo-Neutron Source (PNS) project is a study ... design, simulation and construction an accelerator based neutron source for Boron Neutron Capture Therapy (BNCT). The system uses ... medical linear accelerat...

A. Taheri; A. Torkamani; A. Pazirandeh…

2013-01-01T23:59:59.000Z

246

ORISE: Dose modeling and assessments  

NLE Websites -- All DOE Office Websites (Extended Search)

have participated include: Derivation of DCGLs for the Curtis Bay and Hammond depots Vermont Yankee Nuclear Power Station dose assessment study Radium timepiece dose modeling...

247

Neutron sources and applications  

SciTech Connect

Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

Price, D.L. [ed.] [Argonne National Lab., IL (United States); Rush, J.J. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1994-01-01T23:59:59.000Z

248

Method to determine the position-dependant metal correction factor for dose-rate equivalent laser testing of semiconductor devices  

DOE Patents (OSTI)

A method reconstructs the charge collection from regions beneath opaque metallization of a semiconductor device, as determined from focused laser charge collection response images, and thereby derives a dose-rate dependent correction factor for subsequent broad-area, dose-rate equivalent, laser measurements. The position- and dose-rate dependencies of the charge-collection magnitude of the device are determined empirically and can be combined with a digital reconstruction methodology to derive an accurate metal-correction factor that permits subsequent absolute dose-rate response measurements to be derived from laser measurements alone. Broad-area laser dose-rate testing can thereby be used to accurately determine the peak transient current, dose-rate response of semiconductor devices to penetrating electron, gamma- and x-ray irradiation.

Horn, Kevin M.

2013-07-09T23:59:59.000Z

249

Spallation Neutron Source  

NLE Websites -- All DOE Office Websites (Extended Search)

D/gim D/gim Spallation Neutron Source SNS is an accelerator-based neutron source. This one-of-a-kind facility pro- vides the most intense pulsed neutron beams in the world. When ramped up to its full beam power of 1.4 MW, SNS will be eight times more powerful than today's best facility. It will give researchers more detailed snapshots of the smallest samples of physical and biological materials than ever before

250

Utirik Atoll Dose Assessment  

SciTech Connect

On March 1, 1954, radioactive fallout from the nuclear test at Bikini Atoll code-named BRAVO was deposited on Utirik Atoll which lies about 187 km (300 miles) east of Bikini Atoll. The residents of Utirik were evacuated three days after the fallout started and returned to their atoll in May 1954. In this report we provide a final dose assessment for current conditions at the atoll based on extensive data generated from samples collected in 1993 and 1994. The estimated population average maximum annual effective dose using a diet including imported foods is 0.037 mSv y{sup -1} (3.7 mrem y{sup -1}). The 95% confidence limits are within a factor of three of their population average value. The population average integrated effective dose over 30-, 50-, and 70-y is 0.84 mSv (84, mrem), 1.2 mSv (120 mrem), and 1.4 mSv (140 mrem), respectively. The 95% confidence limits on the population-average value post 1998, i.e., the 30-, 50-, and 70-y integral doses, are within a factor of two of the mean value and are independent of time, t, for t > 5 y. Cesium-137 ({sup 137}Cs) is the radionuclide that contributes most of this dose, mostly through the terrestrial food chain and secondarily from external gamma exposure. The dose from weapons-related radionuclides is very low and of no consequence to the health of the population. The annual background doses in the U. S. and Europe are 3.0 mSv (300 mrem), and 2.4 mSv (240 mrem), respectively. The annual background dose in the Marshall Islands is estimated to be 1.4 mSv (140 mrem). The total estimated combined Marshall Islands background dose plus the weapons-related dose is about 1.5 mSv y{sup -1} (150 mrem y{sup -1}) which can be directly compared to the annual background effective dose of 3.0 mSv y{sup -1} (300 mrem y{sup -1}) for the U. S. and 2.4 mSv y{sup -1} (240 mrem y{sup -1}) for Europe. Moreover, the doses listed in this report are based only on the radiological decay of {sup 137}Cs (30.1 y half-life) and other radionuclides. However, we continually see {sup 137}Cs in the groundwater at all contaminated atolls; the turnover time of the groundwater is about 5 y. The {sup 137}Cs can only get to the groundwater by leaching through the soil column when a portion of the soluble fraction of {sup 137}Cs inventory in the soil is transported to the groundwater when rainfall is heavy enough to cause recharge of the aquifer. This process is causing a loss of {sup 137}Cs out of the root zone of the plants that provides an environmental loss constant ({lambda}{sub env}) in addition to radiological decay {lambda}{sub rad}. Consequently, there is an effective rate of loss, {lambda}{sub eff} = {lambda}{sub rad} + {lambda}{sub env} that is the sum of the radiological and environmental-loss decay constants. We have had, and continue to have, a vigorous program to determine the rate of the environmental loss process. What we do know at this time is that the loss of {sup 137}Cs over time is greater than the estimate based on radiological decay only, and that the actual dose received by the Utirik people over 30-, 50-, or 70-y will be less than those presented in this report.

Robison, W.L.; Conrado, C.L.; Bogen, K.T

1999-10-06T23:59:59.000Z

251

Dose factor entry and display tool for BNCT radiotherapy  

DOE Patents (OSTI)

A system for use in Boron Neutron Capture Therapy (BNCT) radiotherapy planning where a biological distribution is calculated using a combination of conversion factors and a previously calculated physical distribution. Conversion factors are presented in a graphical spreadsheet so that a planner can easily view and modify the conversion factors. For radiotherapy in multi-component modalities, such as Fast-Neutron and BNCT, it is necessary to combine each conversion factor component to form an effective dose which is used in radiotherapy planning and evaluation. The Dose Factor Entry and Display System is designed to facilitate planner entry of appropriate conversion factors in a straightforward manner for each component. The effective isodose is then immediately computed and displayed over the appropriate background (e.g. digitized image).

Wessol, Daniel E. (Bozeman, MT); Wheeler, Floyd J. (Idaho Falls, ID); Cook, Jeremy L. (Greeley, CO)

1999-01-01T23:59:59.000Z

252

Mammary Neoplasia in the Rat following High-Energy Neutron Irradiation  

Science Journals Connector (OSTI)

...traversed by more than 1 secondary par tide, generally a proton. At the doses of...constant over a wide range of neutron energies. The value of b would vary depending upon the relative proportion of high linear-energy-transfer radiation pen unit of dose...

James L. Montour; Richard C. Hard, Jr.; and Roger E. Flora

1977-08-01T23:59:59.000Z

253

Industry - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Industry banner Industry banner Neutron scattering research has applications in practically every field, and neutron research at ORNL is leading to productive partnerships with the industrial and business communities. We welcome proposals for all types of research, including those involving proprietary work. Recent studies have led to discoveries with potential applications in fields such as medicine, energy, and various metals technologies. For more information, please see our recent research highlights. Research Collaborations Industry-Driven Research Benefits Plastics Manufacturing Corning uses VULCAN to test limits of ceramic material for car emission controls, filtration devices Neutrons Probe Inner Workings of Batteries Industry and Neutron Science: Working To Make a Match

254

Neutron wave packet tomography  

E-Print Network (OSTI)

A tomographic technique is introduced in order to determine the quantum state of the center of mass motion of neutrons. An experiment is proposed and numerically analyzed.

G. Badurek; P. Facchi; Y. Hasegawa; Z. Hradil; S. Pascazio; H. Rauch; J. Rehacek; T. Yoneda

2005-03-29T23:59:59.000Z

255

Neutron Science Forum | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

environment for discussion, innovation, and dissemination of information within the neutron scattering community as well as engaging closely related disciplines through...

256

Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

User Office User Program Manager Laura Morris Edwards 865.574.2966 ORNL study uses neutron scattering, supercomputing to demystify forces at play in biofuel production Full...

257

Polarizability of the Neutron  

Science Journals Connector (OSTI)

Experiments on scattering of low-energy neutrons by heavy elements may give information concerning the electric polarizability of the neutron. The relation of the electric polarizability to the low-energy neutron scattering data is developed. One pertinent experiment is discussed and from this an upper bound on the polarizability is obtained. This upper bound to the polarizability ? is an order of magnitude larger than the meson-theoretic estimate of ?. If the value of ? is as small as is predicted by meson theory, or by an analysis of the pion photoproduction data, then it is unlikely to be observed in neutron scattering experiments of the presently achievable accuracy.

R. M. Thaler

1959-05-01T23:59:59.000Z

258

Neutron superfluidity and unusual nuclear shapes in neutron stars crusts  

Science Journals Connector (OSTI)

We calculate in the frame-work of a semiclassical model the neutron superfluidity in the crust of neutron stars, accounting for the presence of unusual....

G. Lazzari; F. V. De Blasio

1994-01-01T23:59:59.000Z

259

Neutron capture cross sections for neutron-rich isotopes  

Science Journals Connector (OSTI)

Average continuum (Hauser-Feshbach) and resonance (Breit-Wigner) neutron capture rates for neutron-rich isotopes, determined on the basis of...

B. Leist; W. Ziegert; M. Wiescher…

1985-01-01T23:59:59.000Z

260

Neutron Diffraction Studies of Proteins  

Science Journals Connector (OSTI)

20 November 1980 research-article Neutron Diffraction Studies of Proteins G. A. Bentley S. A. Mason Neutrons interact differently with protein crystals...hydrogen or deuterium atoms diffract neutrons relatively more strongly, but in addition...

1980-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Neutron and Nuclear Science News  

NLE Websites -- All DOE Office Websites (Extended Search)

News Recent news and events related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science News Links Neutron and Nuclear Science News Media Links Profiles Events at...

262

Neutron Scattering Methods in Chemistry  

Science Journals Connector (OSTI)

Starting with basic properties of the neutron, this chapter reviews the most important neutron scattering methods that provide valuable information for a ... wide, from standard methods of crystallography to neutron

L. Pusztai

2011-01-01T23:59:59.000Z

263

Dose masking feature for BNCT radiotherapy planning  

DOE Patents (OSTI)

A system for displaying an accurate model of isodoses to be used in radiotherapy so that appropriate planning can be performed prior to actual treatment on a patient. The nature of the simulation of the radiotherapy planning for BNCT and Fast Neutron Therapy, etc., requires that the doses be computed in the entire volume. The "entire volume" includes the patient and beam geometries as well as the air spaces in between. Isodoses derived from the computed doses will therefore extend into the air regions between the patient and beam geometries and thus depict the unrealistic possibility that radiation deposition occurs in regions containing no physical media. This problem is solved by computing the doses for the entire geometry and then masking the physical and air regions along with the isodose contours superimposed over the patient image at the corresponding plane. The user is thus able to mask out (remove) the contour lines from the unwanted areas of the image by selecting the appropriate contour masking region from the raster image.

Cook, Jeremy L. (Greeley, CO); Wessol, Daniel E. (Bozeman, MT); Wheeler, Floyd J. (Idaho Falls, ID)

2000-01-01T23:59:59.000Z

264

Dose Reduction Techniques  

SciTech Connect

As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program.

WAGGONER, L.O.

2000-05-16T23:59:59.000Z

265

3D Equilibrium Reconstruction for  

E-Print Network (OSTI)

,dipole jplasma Bexternal M. Drevlak et al. Nuclear Fusion 45 (2005) H.J Gardner, Nuclear Fusion 30 1417? Equilibrium Model Synthetic Signals Input Parameters Currents Vacuum Fields Pressure, etc. These need; pf = p0 + h Equilibrium is defined by a set of input parameters (p0). Reconstruction seeks to find

Columbia University

266

Santo Antonio de Tanna story and reconstruction  

E-Print Network (OSTI)

of the research goals presented on this abstract – the reconstruction of a Portuguese frigate, Santo Antonio de Tanná, from its submerged remains. This thesis focuses on the mechanisms of reconstructing the ship, including the thought process, new computer tools...

Fraga, Tiago Miguel

2009-05-15T23:59:59.000Z

267

Muon Reconstruction and Identification in CMS  

SciTech Connect

We present the design strategies and status of the CMS muon reconstruction and identification identification software. Muon reconstruction and identification is accomplished through a variety of complementary algorithms. The CMS muon reconstruction software is based on a Kalman filter technique and reconstructs muons in the standalone muon system, using information from all three types of muon detectors, and links the resulting muon tracks with tracks reconstructed in the silicon tracker. In addition, a muon identification algorithm has been developed which tries to identify muons with high efficiency while maintaining a low probability of misidentification. The muon identification algorithm is complementary by design to the muon reconstruction algorithm that starts track reconstruction in the muon detectors. The identification algorithm accepts reconstructed tracks from the inner tracker and attempts to quantify the muon compatibility for each track using associated calorimeter and muon detector hit information. The performance status is based on detailed detector simulations as well as initial studies using cosmic muon data.

Everett, A. [Purdue University, West Lafayette, IN, 47906 (United States)

2010-02-10T23:59:59.000Z

268

Neutron Diffraction @ TOPAZ  

NLE Websites -- All DOE Office Websites (Extended Search)

Topaz Guide Bender Topaz Guide Bender Neutron Diffraction @ TOPAZ Workshop on Single Crystal Neutron Diffraction picture 2 September 29 - October 1, 2011 * Spallation Neutron Source * Oak Ridge National Laboratory * Oak Ridge TN, USA TOPAZ 2011 Home Contacts Agenda and Important Deadlines Registration and Payment filler Workshop summary and purpose A workshop on single crystal neutron diffraction will be held at the Spallation Neutron Source at the Oak Ridge National Laboratory (ORNL). It will present invited and contributed talks to showcase cutting edge science and examples where neutron diffraction can make significant contributions; and provide training in neutron structure analysis and sample screening for the preparation of instrument beam-time proposals. TOPAZ is a high resolution wavelength-resolved Laue diffractometer with a versatile sample environment. Commissioning user experiments have demonstrated successfully the instrument capability for structural study of a vitamin B12 derivative, ion distribution in Li-ion battery materials, order and disorder in shape memory intermetallics, magnetic phase transition in multiferroic single crystal and functional thin films. The workshop is directed towards experienced neutron diffraction users and new users alike and encourages members to highlight their research and interest in structure analysis and investigation. The workshop will give opportunity to bring your own single crystal and screen sample quality and scattering power on TOPAZ @ room temperature, to evaluate data collection time and quality for an anticipated experiment. Finally, an opportunity to compose a proposal for neutron beam time (http://neutrons.ornl.gov/users/proposals.shtml) with staff will be provided in the framework of the workshop. The workshop format is well suited for researchers to contribute by showcasing their research and bring their research group or graduate student, who would like to test a single crystal sample. User access training for the ORNL neutron scattering facility will be included. It will be valid for future experiments.

269

Neutron activation experiments in radiochemistry  

Science Journals Connector (OSTI)

Neutron activation experiments in radiochemistry ... Describes experimentation involving the neutron activation of a variety of samples irradiated in a subcritical reactor and a paraffin-moderated source. ...

Karl S. Vorres

1960-01-01T23:59:59.000Z

270

Neutron Stars and Fractal Dimensionality  

E-Print Network (OSTI)

We argue that the material inside Neutron stars behaves anomalously with fractal statistics and that in principle, we could induce mini Neutron stars, with the release of energy.

Burra G. Sidharth

2008-05-06T23:59:59.000Z

271

A history of the neutron  

Science Journals Connector (OSTI)

A history of the neutron ... Describes some of the individuals and the work they did leading to the discovery of the neutron. ...

Vasilis Lavrakas

1952-01-01T23:59:59.000Z

272

Neutron and Nuclear Science Publications  

NLE Websites -- All DOE Office Websites (Extended Search)

Publications Recent publications related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science Publications Chi-Nu Publications DANCE Publications GEANIE...

273

Neutron and Nuclear Science News  

NLE Websites -- All DOE Office Websites (Extended Search)

News Recent news and events related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science News Nuclear science observations and opportunities at the Los Alamos...

274

Neutron Science Research Areas | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Home | Science & Discovery | Neutron Science | Research Areas SHARE Research Areas Neutron scattering research at ORNL covers four broad research areas: biology and soft...

275

LANSCE School on Neutron Scattering:  

NLE Websites -- All DOE Office Websites (Extended Search)

11 th LANSCE School on Neutron Scattering: Materials at the Mesoscale Lujan Center Los Alamos Neutron Science Center Los Alamos National Laboratory lansce.lanl.govneutronschool...

276

Advances in specular neutron reflectometry  

Science Journals Connector (OSTI)

Specular neutron reflectometry provides a depth profile of the scattering ... material. To date, numerous productive applications of neutron reflectometry have been demonstrated. With the new development ... stil...

C.F. Majkrzak; N.F. Berk

2002-12-01T23:59:59.000Z

277

Category:Neutron Log | Open Energy Information  

Open Energy Info (EERE)

Neutron Log page? For detailed information on Neutron Log, click here. Category:Neutron Log Add.png Add a new Neutron Log Technique Pages in category "Neutron Log" This category...

278

8, 40994116, 2008 Reconstruction of the  

E-Print Network (OSTI)

ACPD 8, 4099­4116, 2008 Reconstruction of the solar UV irradiance from LYRA data T. Egorova et al.0 License. Atmospheric Chemistry and Physics Discussions Reconstruction of the solar spectral UV irradiance on behalf of the European Geosciences Union. 4099 #12;ACPD 8, 4099­4116, 2008 Reconstruction of the solar UV

Boyer, Edmond

279

Neutron Capture Therapy  

Science Journals Connector (OSTI)

... . Only those elements which have a high thermal-neutron capture cross-section, such as boron-10, lithium-6, and uranium-235, are useful. This suggestion was first put forward ... was first put forward in 1936 by Locher. The utilization of thermal neutron capture by boron-10 for the treatment of human-brain tumours, chiefly glioblastoma multiforme, has been under investigation ...

1961-09-23T23:59:59.000Z

280

Neutron capture therapies  

DOE Patents (OSTI)

In one embodiment there is provided an application of the .sup.10 B(n,.alpha.).sup.7 Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

Yanch, Jacquelyn C. (Cambridge, MA); Shefer, Ruth E. (Newton, MA); Klinkowstein, Robert E. (Winchester, MA)

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Neutron calibration facilities  

Science Journals Connector (OSTI)

......shut down. A recent development for a thermal neutron calibration field is a neutron guide used at the research reactor GKSS Geesthacht(35). The result is a high-intensity thermal beam providing a flux of up to 106 s1 with a field size of about 2.5 2......

H. Schuhmacher

2004-08-01T23:59:59.000Z

282

Neutron Scattering Software  

NLE Websites -- All DOE Office Websites (Extended Search)

Software Software A new portal for neutron scattering has just been established at neutronsources.org. The information contained here in the Neutron Scattering Web has been transferred to the new site. We will leave the current content here for archival purposes but no new content will be added. We encourage everyone interested in neutron scattering to take full advantage of this exciting new resource for our community. Neutronsources.org Data Formats NeXus: Neutron and X-ray Data Format Crystallographic Binary Format (CBF/imgCIF) Hierarchical Data Format (HDF) Data Analysis and Visualization Data Analysis for Neutron Scattering Experiments (DANSE): distributed data analysis project Large Array Manipulation Program (LAMP): IDL-based data analysis and visualization

283

Industry - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Industry and Neutron Science Industry and Neutron Science Industry and Neutron Science: Working To Make a Match "In fundamental research, we want to know everything. Industry wants to know enough to answer a question." Research Contact: Mike Crawford September 2011, Written by Deborah Counce Mike Crawford and Souleymane Diallo Mike Crawford of Dupont (right) and Souleymane Diallo, instrument scientist for the Backscattering Spectrometer at SNS, prepare a material sample for an experiment on the instrument. Industrial users are starting to eye the potential of neutron science for solving problems that can't be solved in any other way. At the same time, the SNS and HFIR neutron science facilities at ORNL are exploring ways to woo such users and to make a match of it, to the benefit of both.

284

Pocked surface neutron detector  

DOE Patents (OSTI)

The detection efficiency, or sensitivity, of a neutron detector material such as of Si, SiC, amorphous Si, GaAs, or diamond is substantially increased by forming one or more cavities, or holes, in its surface. A neutron reactive material such as of elemental, or any compound of, .sup.10 B, .sup.6 Li, .sup.6 LiF, U, or Gd is deposited on the surface of the detector material so as to be disposed within the cavities therein. The portions of the neutron reactive material extending into the detector material substantially increase the probability of an energetic neutron reaction product in the form of a charged particle being directed into and detected by the neutron detector material.

McGregor, Douglas (Whitmore Lake, MI); Klann, Raymond (Bolingbrook, IL)

2003-04-08T23:59:59.000Z

285

Structure of the Neutron  

Science Journals Connector (OSTI)

In an earlier paper, the contribution of the meson current to the electromagnetic structure of the nucleon was calculated by use of the dispersion relations for pion-nucleon scattering. Here the contribution of the nucleon current to the electromagnetic structure of the neutron is obtained analogously by use of the dispersion relations for neutron-proton scattering. Only the contribution from the one-pion and two-pion states of nucleon-nucleon scattering is considered. It is found that both states reduce the neutron-electron potential, i.e., leads to a smaller charge radius of the neutron. The contribution from the deuteron state is shown to be negligible. The resulting mean-square radii of the neutron, including the contributions of both meson and nucleon current, are (0.23×10-13cm)2 for the charge distribution and (0.41×10-13cm)2 for the magnetic moment distribution with f2=0.08.

Katsumi Tanaka

1959-01-15T23:59:59.000Z

286

THERMAL NEUTRON BACKSCATTER IMAGING.  

SciTech Connect

Objects of various shapes, with some appreciable hydrogen content, were exposed to fast neutrons from a pulsed D-T generator, resulting in a partially-moderated spectrum of backscattered neutrons. The thermal component of the backscatter was used to form images of the objects by means of a coded aperture thermal neutron imaging system. Timing signals from the neutron generator were used to gate the detection system so as to record only events consistent with thermal neutrons traveling the distance between the target and the detector. It was shown that this time-of-flight method provided a significant improvement in image contrast compared to counting all events detected by the position-sensitive {sup 3}He proportional chamber used in the imager. The technique may have application in the detection and shape-determination of land mines, particularly non-metallic types.

VANIER,P.; FORMAN,L.; HUNTER,S.; HARRIS,E.; SMITH,G.

2004-10-16T23:59:59.000Z

287

Displacement damage induce degradation of COTS array \\{CCDs\\} irradiated by neutron beams from a nuclear reactor  

Science Journals Connector (OSTI)

Abstract The experiments of displacement damage effects on COTS array charge coupled devices (CCDs) induced by neutron irradiation from a nuclear reactor are presented. The charge transfer inefficiency (CTI), saturation output signal voltage (VS), dynamic range (DR), dark signal, and camera imaging quality versus neutron fluence are investigated. The degradation mechanisms of the \\{CCDs\\} irradiated by reactor neutron beams are also analyzed. The CTI increase due to neutron displacement damage appears to be proportional to displacement damage dose. The experiments show that VS degradation induced by neutron irradiation is much less than that induced by gamma irradiation. The dark images from the \\{CCDs\\} irradiated by neutrons are given to investigate dark signal degradation. The degradation forms and mechanisms of the camera imaging quality are very different between the reactor neutron displacement damage and the gamma total ionization dose damage. The three samples were exposed by 1 MeV neutron-equivalent fluences of 1×1011, 5×1011, and 1×1012 n/cm2, respectively. A sample was exposed by 1 MeV neutron-equivalent fluences up to 2×1013 n/cm2, and the CCD is a functional failure after irradiation.

Wang Zujun; Chen Wei; Xiao Zhigang; Liu Minbo; Huang Shaoyan; He Baoping; Luo Tongding

2014-01-01T23:59:59.000Z

288

SINGLE CRYSTAL NEUTRON DIFFRACTION.  

SciTech Connect

Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

KOETZLE,T.F.

2001-03-13T23:59:59.000Z

289

Calculation of radiation therapy dose using all particle Monte Carlo transport  

DOE Patents (OSTI)

The actual radiation dose absorbed in the body is calculated using three-dimensional Monte Carlo transport. Neutrons, protons, deuterons, tritons, helium-3, alpha particles, photons, electrons, and positrons are transported in a completely coupled manner, using this Monte Carlo All-Particle Method (MCAPM). The major elements of the invention include: computer hardware, user description of the patient, description of the radiation source, physical databases, Monte Carlo transport, and output of dose distributions. This facilitated the estimation of dose distributions on a Cartesian grid for neutrons, photons, electrons, positrons, and heavy charged-particles incident on any biological target, with resolutions ranging from microns to centimeters. Calculations can be extended to estimate dose distributions on general-geometry (non-Cartesian) grids for biological and/or non-biological media.

Chandler, William P. (Tracy, CA); Hartmann-Siantar, Christine L. (San Ramon, CA); Rathkopf, James A. (Livermore, CA)

1999-01-01T23:59:59.000Z

290

Neutron LifetimeNeutron Lifetime IUCF Colloquium April 13,  

E-Print Network (OSTI)

Neutron LifetimeNeutron Lifetime IUCF Colloquium April 13, 2007 Albert Steyerl Department 940 878.5±0.8 885.7±0.8 new result neutronlifetime(),s year world average Neutron lifetime data #12 world average Neutron lifetime data A. Serebrov et al. 2005Storage of ultra-cold neutrons878.5 ±±±± 0

Steyerl, Albert

291

Effect of electronic reconstruction on cuprate-manganite spin switches.  

SciTech Connect

We examine the anomalous inverse spin switch behavior in La{sub 0.7}Ca{sub 0.3}MnO{sub 3}(LCMO)/YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO)/LCMO trilayers by combined transport studies and polarized neutron reflectometry. Measuring magnetization profiles and magnetoresistance in an in-plane rotating magnetic field, we prove that, contrary to many accepted theoretical scenarios, the relative orientation between the two LCMO's magnetizations is not sufficient to determine the magnetoresistance. Rather the field dependence of magnetoresistance is explained by the interplay between the applied magnetic field and the (exponential tail of the) induced exchange field in YBCO, the latter originating from the electronic reconstruction at the LCMO/YBCO interfaces.

Liu, Y.; Visani, C.; Nemes, N. M.; Fitzsimmons, M. R.; Zhu, L. Y.; Tornos, J.; Zhernenkov, M.; Hoffmann, A.; Leon, C.; Santamaria, J.; te Velthuis, S. G. E. (Materials Science Division); (Universidad Complutense de Madrid); (LANL)

2012-01-01T23:59:59.000Z

292

Development of the JAERI computational dosimetry system (JCDS) for boron neutron capture therapy. Cooperative research  

E-Print Network (OSTI)

The Neutron Beam Facility at JRR-4 enables us to carry out boron neutron capture therapy with epithermal neutron beam. In order to make treatment plans for performing the epithermal neutron beam BNCT, it is necessary to estimate radiation doses in a patient's head in advance. The JAERI Computational Dosimetry System (JCDS), which can estimate distributions of radiation doses in a patient's head by simulating in order to support the treatment planning for epithermal neutron beam BNCT, was developed. JCDS is a software that creates a 3-dimentional head model of a patient by using CT and MRI images, and that generates a input data file automatically for calculation of neutron flux and gamma-ray dose distributions in the brain with the Monte Carlo code MCNP, and that displays these dose distributions on the head model for dosimetry by using the MCNP calculation results. JCDS has any advantages as follows; By using CT data and MRI data which are medical images, a detail three-dimensional model of patient's head is...

Kumada, H; Matsumura, A; Nakagawa, Y; Nose, T; Torii, Y; Uchiyama, J; Yamamoto, K; Yamamoto, T

2003-01-01T23:59:59.000Z

293

Hyperons in neutron stars  

E-Print Network (OSTI)

Using the Dirac-Brueckner-Hartree-Fock approach, the properties of neutron-star matter including hyperons are investigated. In the calculation, we consider both time and space components of the vector self-energies of baryons as well as the scalar ones. Furthermore, the effect of negative-energy states of baryons is partly taken into account. We obtain the maximum neutron-star mass of $2.08\\,M_{\\odot}$, which is consistent with the recently observed, massive neutron stars. We discuss a universal, repulsive three-body force for hyperons in matter.

Katayama, Tetsuya

2015-01-01T23:59:59.000Z

294

Toward IMRT 2D dose modeling using artificial neural networks: A feasibility study  

SciTech Connect

Purpose: To investigate the feasibility of artificial neural networks (ANN) to reconstruct dose maps for intensity modulated radiation treatment (IMRT) fields compared with those of the treatment planning system (TPS). Methods: An artificial feed forward neural network and the back-propagation learning algorithm have been used to replicate dose calculations of IMRT fields obtained from PINNACLE{sup 3} v9.0. The ANN was trained with fluence and dose maps of IMRT fields for 6 MV x-rays, which were obtained from the amorphous silicon (a-Si) electronic portal imaging device of Novalis TX. Those fluence distributions were imported to the TPS and the dose maps were calculated on the horizontal midpoint plane of a water equivalent homogeneous cylindrical virtual phantom. Each exported 2D dose distribution from the TPS was classified into two clusters of high and low dose regions, respectively, based on the K-means algorithm and the Euclidian metric in the fluence-dose domain. The data of each cluster were divided into two sets for the training and validation phase of the ANN, respectively. After the completion of the ANN training phase, 2D dose maps were reconstructed by the ANN and isodose distributions were created. The dose maps reconstructed by ANN were evaluated and compared with the TPS, where the mean absolute deviation of the dose and the {gamma}-index were used. Results: A good agreement between the doses calculated from the TPS and the trained ANN was achieved. In particular, an average relative dosimetric difference of 4.6% and an average {gamma}-index passing rate of 93% were obtained for low dose regions, and a dosimetric difference of 2.3% and an average {gamma}-index passing rate of 97% for high dose region. Conclusions: An artificial neural network has been developed to convert fluence maps to corresponding dose maps. The feasibility and potential of an artificial neural network to replicate complex convolution kernels in the TPS for IMRT dose calculations have been demonstrated.

Kalantzis, Georgios; Vasquez-Quino, Luis A.; Zalman, Travis; Pratx, Guillem; Lei, Yu [Radiation Oncology Department, University of Texas, Health Science Center San Antonio, Texas 78229 and Radiation Oncology Department, Stanford University School of Medicine, Stanford, California 94305 (United States); Radiation Oncology Department, University of Texas, Health Science Center San Antonio, Texas 78229 (United States); Radiation Oncology Department, Stanford University School of Medicine, Stanford, California 94305 (United States); Radiation Oncology Department, University of Texas, Health Science Center San Antonio, Texas 78229 (United States)

2011-10-15T23:59:59.000Z

295

An evaluation of stray neutron interference with routine thermoluminescent dosimetry  

E-Print Network (OSTI)

and measured characteristics of the neutron calibration ran e Source- Detector Distance Scattered Fraction of Direct Flux Calculated Flux Density (n/Sec-cm2) Measured Normalized cps cps 80 cm 90 cm 100 cm 120 cm 200 cm 609 cm 0. 076 0. 093... be appropriate. The gamma dose rate was measured with a standard beta/gamma survey meter (Victoreen 440) and found to be approximately 10 MRad/hr in both positions 1 and 2. 26 RESULTS AND DISCUSSION Rem-meter calibration The calculated neutron flux density...

Bliss, John Lawrence

2012-06-07T23:59:59.000Z

296

Industry - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

PartTec PartTec ORNL, PartTec Inc. Licensing Agreement ORNL and PartTec sign licensing agreement (Front) ORNL Deputy Director for Science & Technology Thomas Zacharia and PartTec CEO Herschel Workman. (Back) Bruce Hannan (SNS), PartTec production manager Craig Kline, Rick Riedel (SNS), Jason Hodges (SNS) and Ron Cooper (SNS). The SNS guys were on the development team. Representatives from Oak Ridge National Laboratory and PartTec, an Indiana-based firm, formally signed a licensing agreement Thursday, Aug. 12, to market an advanced neutron detector system developed for the Spallation Neutron Source. The Shifting Scintillator Neutron Detector can determine the time and position of captured neutrons, which enables researchers to obtain very accurate time-of-flight measurements.

297

Education | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Education banner Education banner Sunil Sinha A Chat with Sunil Sinha, Distinguished Professor of Physics at the University of California-San Diego and speaker at the recent CNMS-SNS Research Forum more... The purpose of the Spallation Neutron Source and the High Flux Isotope Reactor is to facilitate neutron scattering as an integral tool for scientific research and technological development across many scientific and engineering domains within the scientific, academic,and industrial communities. Coupled with this role is a recognized need to inspire, educate, and facilitate the next generation of users and hence foster enhanced use of the unique neutron scattering facilities at ORNL. This is the central theme of the education activities within the Neutron Sciences Directorate (NScD).

298

ORNL Neutron Sciences Instruments  

NLE Websites -- All DOE Office Websites (Extended Search)

Instruments banner Instruments banner ORNL Neutron Sciences Instruments SNS and HFIR provide researchers with two complementary world-class suites of neutron scattering instruments and beam lines. All the instruments are supported by a variety of sample environments and data analysis and visualization capabilities. Before submitting a proposal for a specific instrument, please contact the appropriate instrument scientist to make sure your research is feasible for that instrument. Instruments Currently Available to Users SNS Beam Line Instrument Name HFIR Beam Line Instrument Name 1B NOMAD Nanoscale-Ordered Materials Diffractometer CG-1 Development Beam Line 2 BASIS Backscattering Spectrometer CG-1D IMAGING Neutron Imaging Prototype Facility 3 SNAP Spallation Neutrons and Pressure Diffractometer CG-2 GP-SANS

299

Pulsed Neutron Powder Diffraction  

Science Journals Connector (OSTI)

The nature and scope of powder diffraction with a white, pulsed beam of neutrons is discussed. Analysis of the data by the Rietveld profile technique is described in brief, and a range of applications in solid...

A. K. Cheetham

1988-01-01T23:59:59.000Z

300

Neutron Science Center  

NLE Websites -- All DOE Office Websites (Extended Search)

to have rare opportunity to tour Neutron Science Center May 10, 2011 LANL Rosenfest will celebrate life of LANSCE founder Louis Rosen and offer tour LOS ALAMOS, New Mexico, May 10,...

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Shifting scintillator neutron detector  

DOE Patents (OSTI)

Provided are sensors and methods for detecting thermal neutrons. Provided is an apparatus having a scintillator for absorbing a neutron, the scintillator having a back side for discharging a scintillation light of a first wavelength in response to the absorbed neutron, an array of wavelength-shifting fibers proximate to the back side of the scintillator for shifting the scintillation light of the first wavelength to light of a second wavelength, the wavelength-shifting fibers being disposed in a two-dimensional pattern and defining a plurality of scattering plane pixels where the wavelength-shifting fibers overlap, a plurality of photomultiplier tubes, in coded optical communication with the wavelength-shifting fibers, for converting the light of the second wavelength to an electronic signal, and a processor for processing the electronic signal to identify one of the plurality of scattering plane pixels as indicative of a position within the scintillator where the neutron was absorbed.

Clonts, Lloyd G; Cooper, Ronald G; Crow, Jr., Morris Lowell; Hannah, Bruce W; Hodges, Jason P; Richards, John D; Riedel, Richard A

2014-03-04T23:59:59.000Z

302

Scattering of Slow Neutrons  

Science Journals Connector (OSTI)

1 September 1937 research-article Scattering of Slow Neutrons M. Goldhaber G. H. Briggs The Royal Society is collaborating with JSTOR to digitize, preserve, and extend access to Proceedings...

1937-01-01T23:59:59.000Z

303

Neutron Diffraction Texture Analysis  

Science Journals Connector (OSTI)

...conducted at Chalk River (Canada), Geesthacht (Germany), LLB (France) and NIST...deformed limestone that was measured at Geesthacht with this method. It is also possible...with monochromatic neutrons at GKSS, Geesthacht. Equal area projection, linear contours...

Hans-Rudolf Wenk

304

Neutron stars - thermal emitters  

E-Print Network (OSTI)

Confronting theoretical models with observations of thermal radiation emitted by neutron stars is one of the most important ways to understand the properties of both, superdense matter in the interiors of the neutron stars and dense magnetized plasmas in their outer layers. Here we review the theory of thermal emission from the surface layers of strongly magnetized neutron stars, and the main properties of the observational data. In particular, we focus on the nearby sources for which a clear thermal component has been detected, without being contaminated by other emission processes (magnetosphere, accretion, nebulae). We also discuss the applications of the modern theoretical models of the formation of spectra of strongly magnetized neutron stars to the observed thermally emitting objects.

Potekhin, A Y; Pons, J A

2014-01-01T23:59:59.000Z

305

Clifford G. Shull, Neutron Diffraction, Hydrogen Atoms, and Neutron  

Office of Scientific and Technical Information (OSTI)

Clifford Shull, Neutron Diffraction, and Neutron Scattering Clifford Shull, Neutron Diffraction, and Neutron Scattering Resources with Additional Information Clifford G. Shull was awarded the 1994 Nobel Prize in Physics "for the development of the neutron diffraction technique". 'Professor Shull's prize was awarded for his pioneering work in neutron scattering, a technique that reveals where atoms are within a material like ricocheting bullets reveal where obstacles are in the dark. Clifford Shull Photo Courtesy of Oak Ridge National Laboratory When a beam of neutrons is directed at a given material, the neutrons bounce off, or are scattered by, atoms in the sample being investigated. The neutrons' directions change, depending on the location of the atoms they hit, and a diffraction pattern of the atoms' positions can then be obtained.

306

Iterative methods for dose reduction and image enhancement in tomography  

DOE Patents (OSTI)

A system and method for creating a three dimensional cross sectional image of an object by the reconstruction of its projections that have been iteratively refined through modification in object space and Fourier space is disclosed. The invention provides systems and methods for use with any tomographic imaging system that reconstructs an object from its projections. In one embodiment, the invention presents a method to eliminate interpolations present in conventional tomography. The method has been experimentally shown to provide higher resolution and improved image quality parameters over existing approaches. A primary benefit of the method is radiation dose reduction since the invention can produce an image of a desired quality with a fewer number projections than seen with conventional methods.

Miao, Jianwei; Fahimian, Benjamin Pooya

2012-09-18T23:59:59.000Z

307

Data Analysis & Visualization | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Data Analysis and Visualization SHARE Neutron Data Analysis and Visualization As the data sets generated by the increasingly powerful neutron scattering instruments at HFIR...

308

Science Education Programs | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

with Neutrons Graduate & Post-doctoral Programs Student & Teacher Programs Science Forum Neutron Scattering Tutorials Kids' Corner NScD Careers Supporting Organizations Neutron...

309

Fast Pulsing Neutron Generators for Security Application  

E-Print Network (OSTI)

FAST PULSING NEUTRON GENERATORS FOR SECURITY APPLICATION* Q.time/fast pulsing neutron generator is needed primarily forA compact neutron generator, currently being developed in

Ji, Q.

2010-01-01T23:59:59.000Z

310

Leading neutron spectra  

E-Print Network (OSTI)

It is shown that the observation of the spectra of leading neutrons from proton beams can be a good probe of absorptive and migration effects. We quantify how these effects modify the Reggeized pion-exchange description of the measurements of leading neutrons at HERA. We are able to obtain a satisfactory description of all the features of these data. We also briefly discuss the corresponding data for leading baryons produced in hadron-hadron collisions.

A. B. Kaidalov; V. A. Khoze; A. D. Martin; M. G. Ryskin

2006-02-23T23:59:59.000Z

311

MAGNETIC NEUTRON SCATTERING  

SciTech Connect

Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern science, ranging from large-scale structures and dynamics of polymers and biological systems, to electronic properties of today's technological materials. Neutron scattering developed into a vast field, encompassing many different experimental techniques aimed at exploring different aspects of matter's atomic structure and dynamics. Modern magnetic neutron scattering includes several specialized techniques designed for specific studies and/or particular classes of materials. Among these are magnetic reflectometry aimed at investigating surfaces, interfaces, and multilayers, small-angle scattering for the large-scale structures, such as a vortex lattice in a superconductor, and neutron spin-echo spectroscopy for glasses and polymers. Each of these techniques and many others offer exciting opportunities for examining magnetism and warrant extensive reviews, but the aim of this chapter is not to survey how different neutron-scattering methods are used to examine magnetic properties of different materials. Here, we concentrate on reviewing the basics of the magnetic neutron scattering, and on the recent developments in applying one of the oldest methods, the triple axis spectroscopy, that still is among the most extensively used ones. The developments discussed here are new and have not been coherently reviewed. Chapter 2 of this book reviews magnetic small-angle scattering, and modern techniques of neutron magnetic reflectometry are discussed in Chapter 3.

ZALIZNYAK,I.A.; LEE,S.H.

2004-07-30T23:59:59.000Z

312

Neutron Radii in Nuclei and the Neutron Equation of State  

Science Journals Connector (OSTI)

The root-mean-square radius for neutrons in nuclei is investigated in the Skyrme Hartree-Fock model. The main source of theoretical variation comes from the exchange part of the density-dependent interaction which can be related to a basic property of the neutron equation of state. A precise measurement of the neutron radius in 208Pb would place an important new constraint on the equation of state for neutron matter. The Friedman-Pandharipande neutron equation of state would lead to a very precise value of 0.16±0.02 fm for the difference between the neutron and the proton root-mean-square radius in 208Pb.

B. Alex Brown

2000-12-18T23:59:59.000Z

313

Multibody Models for Vehicle Accident Reconstruction  

Science Journals Connector (OSTI)

Simplified multibody models can be used to reconstruct accidents involving complex dynamics, particularly, in the first stages of accident investigation, accidents involving motorcycles and pedestrians [1], [2].

Ricardo J. F. Portal; João M. P. Dias

2006-01-01T23:59:59.000Z

314

Circuit reconstruction tools today Stephen J Smith  

E-Print Network (OSTI)

Circuit reconstruction tools today Stephen J Smith To understand how a brain processes information, Stanford University School of Medicine, Stanford, CA 94305, United States Corresponding author: Smith

Born, Richard

315

Neutron-Neutron Scattering at Low Energies  

Science Journals Connector (OSTI)

This paper investigates the information contained in a neutron-neutron scattering experiment at low energies which could be performed by colliding beams coming from an underground nuclear explosion. The significance of such an experiment is discussed from the point of view of a check on charge symmetry and charge independence, and it is found that because of the electromagnetic complications in proton-proton scattering, and because of the proton-neutron mass difference, the knowledge of neutron-neutron scattering would be of considerable value. The functional form of the experimental data which is most convenient for analysis and the approximate relative magnitude of the terms is investigated, and it is concluded that for the kind of experiment which is envisaged (measuring cross sections to 10% from 20 keV to 2 MeV) only two parameters should be kept in the effective-range expansion. The connection between the number and distribution of energies at which the cross section is measured and the error on the individual measurements, on the one hand, and the accuracy of the effective-range parameters deduced from the experiments, on the other, is given explicitly and is found also to depend on the absolute magnitude of the scattering length. The results show that ten 10% measurements, suitably distributed between 20 keV and 2 MeV, can determine the sign of the scattering length to four standard deviations, the magnitude of the effective range to 50-70%, and the magnitude of the scattering length to about 3%. Finally, the relationship between the variation of the effective-range parameters and the corresponding variation in the parameters of the scattering potential is studied, and it is found that, while this relationship is strongly shape-dependent, a small change in the potential parameters, in any case, results in a large change in the scattering length, but a small one in the effective range. Numerical relationships show that, even in the worst case, the variation in the scattering length is about eight times the variation in the potential parameter. It is concluded that a 10% experiment at 20 energies between 20 keV and 2 MeV would be able to get information on the potential parameters sufficiently accurately so that charge-dependent or charge-symmetry violating effects could be detected.

Michael J. Moravcsik

1964-11-09T23:59:59.000Z

316

Methodology for reconstruction of historical food consumption estimates  

SciTech Connect

This report was written to provide the food consumption methodology to be used in the Hanford Environmental Dose Reconstruction (HDER) Project beyond Phase I (which ended in July 1990). In Phase I (Callaway 1992), baseline food consumption estimates (grams per day) for 10 primary food types in the original 10-county study region were derived from the 1977--1978 National Food Consumption Survey (USDA 1983). The baseline estimates were multiplied by the 1945:1977 ratios to produce consumption estimates for 1945. This ratio backcasting method used in Phase I to project consumption estimates from 1977 back to 1945 will be refined using additional USDA data to improve and document the acceptability of the ratios for deriving backcast consumption estimates. The number of food types and population groups will be expanded to provide more disaggregated estimates of food consumption. Food consumption estimates will be developed for 1945, 1951, and 1957. A database of individual diets will be created from which daily diets will be randomly selected for use in the dose model to calculate doses for reference individuals.

Anderson, D.M.

1992-05-01T23:59:59.000Z

317

Neutron degeneracy and plasma physics effects on radiative neutron captures in neutron star crust  

Science Journals Connector (OSTI)

We consider the astrophysical reaction rates for radiative neutron capture reactions (n,?) in the crust of a neutron star. The presence of degenerate neutrons at high densities (mainly in the inner crust) can drastically affect the reaction rates. Standard rates assuming a Maxwell-Boltzmann distribution for neutrons can underestimate the rates by several orders of magnitude. We derive simple analytical expressions for reaction rates at a variety of conditions with account for neutron degeneracy. We also discuss the plasma effects on the outgoing radiative transition channel in neutron radiative capture reactions and show that these effects can also increase the reaction rates by a few orders of magnitude. In addition, using detailed balance, we analyze the effects of neutron degeneracy and plasma physics on reverse (?,n) photodisintegration. We discuss the dependence of the reaction rates on temperature and neutron chemical potential and outline the efficiency of these reactions in the neutron star crust.

P. S. Shternin; M. Beard; M. Wiescher; D. G. Yakovlev

2012-07-24T23:59:59.000Z

318

Neutron-deuteron breakup reaction as a tool for studying neutron-neutron interactions  

SciTech Connect

An analysis of the most recent data on the reaction nd {yields} pnn revealed a serious discrepancy between theoretical predictions and cross sections measured for this reaction in various configurations where the role of neutron-neutron interactions is important. In view of this, it seems necessary both to develop theoretical approaches and to obtain new experimental data. For this purpose, a setup for studying the neutron-deuteron breakup reaction was created at the Institute for Nuclear Research on the basis of the neutron beam in the RADEX channel and deuterium targets. This facility makes it possible to perform experiments over a broad region of primary-neutron energies (10-60 MeV) and in various (final-state interaction, quasifree scattering, and spatial-star) configurations. Preliminary results of the respective experiment were obtained for configurations of final-state neutron-neutron interaction and quasifree neutron-neutron scattering.

Konobeevski, E. S., E-mail: konobeev@inr.ru; Zuyev, S. V.; Mordovskoy, M. V.; Potashev, S. I.; Sharapov, I. M. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)] [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)

2013-11-15T23:59:59.000Z

319

Neutron lifetime measurements using gravitationally trapped ultracold neutrons  

E-Print Network (OSTI)

Our experiment using gravitationally trapped ultracold neutrons (UCN) to measure the neutron lifetime is reviewed. Ultracold neutrons were trapped in a material bottle covered with perfluoropolyether. The neutron lifetime was deduced from comparison of UCN losses in the traps with different surface-to-volume ratios. The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. In this experiment, the UCN storage time is brought closer to the neutron lifetime than in any experiments before:the probability of UCN losses from the trap was only 1% of that for neutron beta decay. The neutron lifetime obtained,878.5+/-0.7stat+/-0.3sys s, is the most accurate experimental measurement to date.

A. P. Serebrov; V. E. Varlamov; A. G. Kharitonov; A. K. Fomin; Yu. N. Pokotilovski; P. Geltenbort; I. A. Krasnoschekova; M. S. Lasakov; R. R. Taldaev; A. V. Vassiljev; O. M. Zherebtsov

2007-02-06T23:59:59.000Z

320

Novel neutron focusing mirrors for compact neutron sources  

E-Print Network (OSTI)

We demonstrated neutron beam focusing and neutron imaging using axisymmetric optics, based on pairs of confocal ellipsoid and hyperboloid mirrors. Such systems, known as Wolter mirrors, are commonly used in x-ray telescopes. ...

Gubarev, M.V.

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321

Neutron skin of nuclei near the neutron drip line  

Science Journals Connector (OSTI)

Performing Skyrme-type deformed Hartree-Fock calculations, the possible presence of neutron skin in nuclei towards neutron drip line is studied. The thickness of the neutron skin is found to be nearly constant in all directions if it is measured perpendicular to the surface, and in a given nucleus the number of neutrons being inside of the neutron skin is almost independent of the deformation (namely, spherical shape or normal deformation or superdeformation). In the region of medium-heavy nuclei our calculation shows the presence of a series of neutron-rich nuclei, in which a neutron skin is present and yet the neutron one-particle spectra are far from those in a harmonic oscillator (plus spin-orbit) potential.

I. Hamamoto and X. Z. Zhang

1995-11-01T23:59:59.000Z

322

Neutron lifetime measurements using gravitationally trapped ultracold neutrons  

SciTech Connect

Our experiment using gravitationally trapped ultracold neutrons (UCN) to measure the neutron lifetime is reviewed. Ultracold neutrons were trapped in a material bottle covered with perfluoropolyether. The neutron lifetime was deduced from comparison of UCN losses in the traps with different surface-to-volume ratios. The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. In this experiment, the UCN storage time is brought closer to the neutron lifetime than in any experiments before: the probability of UCN losses from the trap was only 1% of that for neutron {beta} decay. The neutron lifetime obtained, 878.5{+-}0.7{sub stat}{+-}0.3{sub sys} s, is the most accurate experimental measurement to date.

Serebrov, A. P.; Varlamov, V. E.; Kharitonov, A. G.; Fomin, A. K.; Krasnoschekova, I. A.; Lasakov, M. S.; Taldaev, R. R.; Vassiljev, A. V.; Zherebtsov, O. M. [Petersburg Nuclear Physics Institute, Russian Academy of Sciences, RU-188300 Gatchina, Leningrad District (Russian Federation); Pokotilovski, Yu. N. [Joint Institute for Nuclear Research, RU-141980 Dubna, Moscow Region (Russian Federation); Geltenbort, P. [Institut Max von Laue Paul Langevin, Boite Postal 156, F-38042 Grenoble Cedex 9 (France)

2008-09-15T23:59:59.000Z

323

Neutron Scattering Instrumentation for Biology at Spallation Neutron Sources  

Science Journals Connector (OSTI)

Conventional wisdom holds that since biological entities are large, they must be studied with cold neutrons, a domain in which reactor sources of neutrons are often supposed to be pre-eminent. ... fact, the curre...

Roger Pynn

1996-01-01T23:59:59.000Z

324

Electron-neutron scattering and transport properties of neutron stars  

E-Print Network (OSTI)

We show that electrons can couple to the neutron excitations in neutron stars and find that this can limit their contribution to the transport properties of dense matter, especially the shear viscosity. The coupling between electrons and neutrons is induced by protons in the core, and by ions in the crust. We calculate the effective electron-neutron interaction for the kinematics of relevance to the scattering of degenerate electrons at high density. We use this interaction to calculate the electron thermal conductivity, electrical conductivity, and shear viscosity in the neutron star inner crust, and in the core where we consider both normal and superfluid phases of neutron-rich matter. In some cases, particularly when protons are superconducting and neutrons are in their normal phase, we find that electron-neutron scattering can be more important than the other scattering mechanisms considered previously.

Bertoni, Bridget; Rrapaj, Ermal

2014-01-01T23:59:59.000Z

325

Low Dose Radiation  

NLE Websites -- All DOE Office Websites (Extended Search)

Ancient Salt Beds Ancient Salt Beds Repository Science Renewable Energy The WIPP Underground may be ideal to study effects of Very Low Dose Rates on Biological Systems Low Background Radiation Experiment We're all bathing in it. It's in the food we eat, the water we drink, the soil we tread and even the air we breathe. It's background radiation, it's everywhere and we can't get away from it. But what would happen if you somehow "pulled the plug" on natural background radiation? Would organisms suffer or thrive if they grew up without their constant exposure to background radiation? That's what a consortium of scientists conducting an experiment at the Waste Isolation Pilot Plant aim to find out. Despite being an underground repository for transuranic radioactive waste,

326

Standardized radiological dose evaluations  

SciTech Connect

Following the end of the Cold War, the mission of Rocky Flats Environmental Technology Site changed from production of nuclear weapons to cleanup. Authorization baseis documents for the facilities, primarily the Final Safety Analysis Reports, are being replaced with new ones in which accident scenarios are sorted into coarse bins of consequence and frequency, similar to the approach of DOE-STD-3011-94. Because this binning does not require high precision, a standardized approach for radiological dose evaluations is taken for all the facilities at the site. This is done through a standard calculation ``template`` for use by all safety analysts preparing the new documents. This report describes this template and its use.

Peterson, V.L.; Stahlnecker, E.

1996-05-01T23:59:59.000Z

327

Improved proton computed tomography by dual modality image reconstruction  

SciTech Connect

Purpose: Proton computed tomography (CT) is a promising image modality for improving the stopping power estimates and dose calculations for particle therapy. However, the finite range of about 33 cm of water of most commercial proton therapy systems limits the sites that can be scanned from a full 360° rotation. In this paper the authors propose a method to overcome the problem using a dual modality reconstruction (DMR) combining the proton data with a cone-beam x-ray prior. Methods: A Catphan 600 phantom was scanned using a cone beam x-ray CT scanner. A digital replica of the phantom was created in the Monte Carlo code Geant4 and a 360° proton CT scan was simulated, storing the entrance and exit position and momentum vector of every proton. Proton CT images were reconstructed using a varying number of angles from the scan. The proton CT images were reconstructed using a constrained nonlinear conjugate gradient algorithm, minimizing total variation and the x-ray CT prior while remaining consistent with the proton projection data. The proton histories were reconstructed along curved cubic-spline paths. Results: The spatial resolution of the cone beam CT prior was retained for the fully sampled case and the 90° interval case, with the MTF = 0.5 (modulation transfer function) ranging from 5.22 to 5.65?linepairs/cm. In the 45° interval case, the MTF = 0.5 dropped to 3.91?linepairs/cm For the fully sampled DMR, the maximal root mean square (RMS) error was 0.006 in units of relative stopping power. For the limited angle cases the maximal RMS error was 0.18, an almost five-fold improvement over the cone beam CT estimate. Conclusions: Dual modality reconstruction yields the high spatial resolution of cone beam x-ray CT while maintaining the improved stopping power estimation of proton CT. In the case of limited angles, the use of prior image proton CT greatly improves the resolution and stopping power estimate, but does not fully achieve the quality of a 360° proton CT scan.

Hansen, David C., E-mail: dch@ki.au.dk; Bassler, Niels [Experimental Clinical Oncology, Aarhus University, 8000 Aarhus C (Denmark)] [Experimental Clinical Oncology, Aarhus University, 8000 Aarhus C (Denmark); Petersen, Jørgen Breede Baltzer [Medical Physics, Aarhus University Hospital, 8000 Aarhus C (Denmark)] [Medical Physics, Aarhus University Hospital, 8000 Aarhus C (Denmark); Sørensen, Thomas Sangild [Computer Science, Aarhus University, 8000 Aarhus C, Denmark and Clinical Medicine, Aarhus University, 8200 Aarhus N (Denmark)] [Computer Science, Aarhus University, 8000 Aarhus C, Denmark and Clinical Medicine, Aarhus University, 8200 Aarhus N (Denmark)

2014-03-15T23:59:59.000Z

328

The neutron identified: Sir James Chadwick  

Science Journals Connector (OSTI)

The neutron identified: Sir James Chadwick ... Uses source material to describe the discovery of the neutron by James Chadwick. ...

Alfred B. Garrett

1962-01-01T23:59:59.000Z

329

Portable Neutron Sensors for Emergency Response Operations  

SciTech Connect

This slide-show presents neutron measurement work, including design, use and performance of different neutron detection systems.

Mukhopadhyay, S., Maurer, R., Detweiler, R.

2012-06-22T23:59:59.000Z

330

Neutron shielding and activation of the MASTU device and surrounds  

E-Print Network (OSTI)

A significant functional upgrade is planned for the Mega Ampere Spherical Tokamak (MAST) device, located at Culham in the UK, including the implementation of a notably greater neutral beam injection power. This upgrade will cause the emission of a substantially increased intensity of neutron radiation for a substantially increased amount of time upon operation of the device. Existing shielding and activation precautions are shown to prove insufficient in some regards, and recommendations for improvements are made, including the following areas: shielding doors to MAST shielded facility enclosure (known as "the blockhouse"); north access tunnel; blockhouse roof; west cabling duct. In addition, some specific neutronic dose rate questions are addressed and answered; those discussed here relate to shielding penetrations and dose rate reflected from the air above the device ("skyshine").

Taylor, David; Turner, Andrew; Davis, Andrew

2014-01-01T23:59:59.000Z

331

GROUND-WATER CONTRIBUTION TO DOSE FROM PAST HANFORD OPERATIONS  

SciTech Connect

The Hanford Environmental Dose Reconstruction (HEOR) Project is being conducted to estimate radiation doses that populations and individuals could have received from Hanford Site operations from 1944 to the present. Four possible pathways by which radionuclides originating in ground water on the Hanford Site could have reached the public have been identified: 1) through contaminated ground water migrating to the Columbia River; 2) through wells on or adjacent to the Hanford Site; 3) through wells that draw some or all of their water from the Columbia River (riparian wells); and 4) through atmospheric deposition resulting in the contamination of a small watershed that, in turn, results in contamination of a shallow well or spring. These four pathways make up the "ground-water pathway ," which is the subject of this study. The objective of the study was to assess the extent to which the groundwater pathway contributed to radiation doses that populations or individuals may have received from past operations at Hanford. The assessment presented in this report was performed by 1) reviewing the extensive ?literature on ground water and ground-water monitoring at Hanford and 2) performing simple calculations to estimate radionuclide concentrations in ground water and the Columbia River resulting from ground-water discharge. Radiation doses that would result from exposure to this ground water and surface water were calculated. The study conclusion is that the ground-water pathways did not contribute significantly to dose. Compared with background radiation in the TriCities {300 mrem/yr), estimated doses are small: 0.02 mrem/yr effective dose equivalent from discharge of contaminated ground water to the Columbia River; 1 mrem/yr effective dose equivalent from Hanford Site wells; 11 mrem/yr effective dose equivalent from riparian wells; and 1 mrem/yr effective dose equivalent from the watershed. Because the estimated doses are so small, the recommendation is that further work on the ground-water pathway be limited to tracking ongoing ground-water studies at the Hanford Site.

Freshley, M. D.; Thorne, P. D.

1992-01-01T23:59:59.000Z

332

Intensity modulated neutron radiotherapy optimization by photon proxy  

SciTech Connect

Purpose: Introducing intensity modulation into neutron radiotherapy (IMNRT) planning has the potential to mitigate some normal tissue complications seen in past neutron trials. While the hardware to deliver IMNRT plans has been in use for several years, until recently the IMNRT planning process has been cumbersome and of lower fidelity than conventional photon plans. Our in-house planning system used to calculate neutron therapy plans allows beam weight optimization of forward planned segments, but does not provide inverse optimization capabilities. Commercial treatment planning systems provide inverse optimization capabilities, but currently cannot model our neutron beam. Methods: We have developed a methodology and software suite to make use of the robust optimization in our commercial planning system while still using our in-house planning system to calculate final neutron dose distributions. Optimized multileaf collimator (MLC) leaf positions for segments designed in the commercial system using a 4 MV photon proxy beam are translated into static neutron ports that can be represented within our in-house treatment planning system. The true neutron dose distribution is calculated in the in-house system and then exported back through the MATLAB software into the commercial treatment planning system for evaluation. Results: The planning process produces optimized IMNRT plans that reduce dose to normal tissue structures as compared to 3D conformal plans using static MLC apertures. The process involves standard planning techniques using a commercially available treatment planning system, and is not significantly more complex than conventional IMRT planning. Using a photon proxy in a commercial optimization algorithm produces IMNRT plans that are more conformal than those previously designed at our center and take much less time to create. Conclusions: The planning process presented here allows for the optimization of IMNRT plans by a commercial treatment planning optimization algorithm, potentially allowing IMNRT to achieve similar conformality in treatment as photon IMRT. The only remaining requirements for the delivery of very highly modulated neutron treatments are incremental improvements upon already implemented hardware systems that should be readily achievable.

Snyder, Michael; Hammoud, Ahmad; Bossenberger, Todd; Spink, Robyn; Burmeister, Jay [Karmanos Cancer Center, Wayne State University School of Medicine, Detroit, Michigan 48201 (United States)

2012-08-15T23:59:59.000Z

333

Neutron scattering above 25 MeV with monoenergetic neutrons  

Science Journals Connector (OSTI)

Technical problems encountered in measuring elastic and inelastic neutron scattering at kinetic energies well above 25 MeV are considered by extrapolating from experience with lower energy neutrons. It is concluded that all of the techniques required for a high?quality systematic study of neutron scattering—with the notable exception of a suitable accelerator facility—are at hand.

Roger W. Finlay

1985-01-01T23:59:59.000Z

334

Sandia Neutron Detector Is Based on Polyacetylene  

Science Journals Connector (OSTI)

Sandia Neutron Detector Is Based on Polyacetylene ... It also might form the basis of an electrically readable dosimeter that records neutron flux (measured as neutrons per square centimeter) as well as a detector that could provide a cross-sectional image of neutron flux with high spatial resolution. ... Hence, most neutron detectors use a converter material that converts the neutrons to charged particles. ...

RUDY BAUM

1987-02-09T23:59:59.000Z

335

Neutron Science | More Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

ORNL's long history of neutron science began in the 1940s with the pioneering neutron scattering studies of Ernest Wollan and Clifford Shull. Shull was co-recipient of...

336

High flux compact neutron generators  

E-Print Network (OSTI)

High Flux Compact Neutron Generators ‡ J. Reijonen §,1 , T-Compact high flux neutron generators are developed at thevoltage feed through of the generator is shown in Fig. 4.

Reijonen, J.; Lou, T.-P.; Tolmachoff, B.; Leung, K.-N.; Verbeke, J.; Vujic, J.

2001-01-01T23:59:59.000Z

337

Neutron Scattering Conference Archive  

NLE Websites -- All DOE Office Websites (Extended Search)

Conference Archive Conference Archive A new portal for neutron scattering has just been established at neutronsources.org. The information contained here in the Neutron Scattering Web has been transferred to the new site. We will leave the current content here for archival purposes but no new content will be added. We encourage everyone interested in neutron scattering to take full advantage of this exciting new resource for our community. Neutronsources.org 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 2000 June 12-14, 2000 Workshop on "New Opportunities for Better User Group Software (NOBUGS III)" Location Daresbury Laboratory, Cheshire, UK Contact Mark Enderby, Daresbury Laboratory Email M.J.Enderby@dl.ac.uk URL http://nobugs.dl.ac.uk/

338

Industry - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Former User Group Chair Enthusiastic About Relevance of Neutron Scattering Former User Group Chair Enthusiastic About Relevance of Neutron Scattering to Industrial Research Former User Group Chair Mike Crawford Mike Crawford, DuPont Research and Development. The drive is intensifying to encourage research partnerships between Neutron Sciences and private industry. Such partnerships, a long-term strategic goal set by the DOE's Basic Energy Sciences Advisory Committee, will deliver industry and its technological problems to SNS and HFIR, where joint laboratory-industry teams can use the unparalleled resources available here to resolve them. "SNS is a tremendous facility. It has the potential to have a couple of thousand user visits a year and, if they build another target station in the future, you're probably talking about 4000 user visits a year,"

339

Contacts | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Points of Contact Science Points of Contact Name Research Area Doug Abernathy Wide Angular-Range Chopper Spectrometer (ARCS). Atomic-scale dynamics at thermal and epithermal energies Ke An Engineering Materials Diffractometer (VULCAN). Residual stress, deformation mechanism of materials, phase transitions/transformation, and in situ/operando neutron diffraction in material systems (e.g., working batteries). John Ankner Liquids Reflectometer (LR). Density profiles normal to the surface at liquid surfaces and liquid interfaces Bryan Chakoumakos Nuclear and magnetic crystal structure systematics and structure-property relationships among inorganic materials, powder and single-crystal neutron and x-ray diffraction methods Leighton Coates Macromolecular Neutron Diffractometer (MaNDi). Protein crystallography, biological structure and function

340

Cooling of neutron stars  

Science Journals Connector (OSTI)

On the basis of current physical understanding, it is impossible to predict with confidence the interior constitution of neutron stars. Cooling of neutron stars provides a possible way of discriminating among possible states of matter within them. In the standard picture of cooling by neutrino emission developed over the past quarter of a century, neutron stars are expected to cool relatively slowly if their cores are made up of nucleons, and to cool faster if matter is in an exotic state, such as a pion condensate, a kaon condensate, or quark matter. This view has recently been called into question by the discovery of a number of other processes that could lead to copious neutrino emission and rapid cooling.

C. J. Pethick

1992-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Ultrafast neutron detector  

DOE Patents (OSTI)

The invention comprises a neutron detector (50) of very high temporal resolution that is particularly well suited for measuring the fusion reaction neutrons produced by laser-driven inertial confinement fusion targets. The detector comprises a biased two-conductor traveling-wave transmission line (54, 56, 58, 68) having a uranium cathode (60) and a phosphor anode (62) as respective parts of the two conductors. A charge line and Auston switch assembly (70, 72, 74) launch an electric field pulse along the transmission line. Neutrons striking the uranium cathode at a location where the field pulse is passing, are enabled to strike the phosphor anode and produce light that is recorded on photographic film (64). The transmission line may be variously configured to achieve specific experimental goals.

Wang, Ching L. (Livermore, CA)

1987-01-01T23:59:59.000Z

342

Cavity Field Reconstruction at Finite Temperature  

E-Print Network (OSTI)

We present a scheme to reconstruct the quantum state of a field preparedinside a lossy cavity at finite temperature. Quantum coherences are normallydestroyed by the interaction with an environment, but we show that it ispossible to recover complete information about the initial state (beforeinteraction with its environment), making possible to reconstruct any$s$-parametrized quasiprobability distribution, in particular, the Wignerfunction.

Moya-Cessa, H; Tombesi, P; Roversi, J A

2000-01-01T23:59:59.000Z

343

Forward Rasterization: A Reconstruction Algorithm for  

E-Print Network (OSTI)

-buffer sample- selection method, designed to ensure that the set of selected samples covers every visibleForward Rasterization: A Reconstruction Algorithm for Image-Based Rendering TROl-019 May 29, 2001: A RECONSTRUCTION ALGORITHM FOR IMAGE-BASED RENDERING by Voicu Sebastian Popescu A dissertation submitted

North Carolina at Chapel Hill, University of

344

Spectrum Sensing and Reconstruction for Cognitive Radio  

E-Print Network (OSTI)

Spectrum Sensing and Reconstruction for Cognitive Radio Amanpreet S Saini, Zhen Hu, Robert Qiu with spectrum sensing and spectrum reconstruction under the umbrella of cognitive radio which is the smart radio to explore and exploit the free spectrum. Spectrum analyzer is used to emulate cognitive radio to do spectrum

Qiu, Robert Caiming

345

Muon reconstruction with AMANDA Christopher Wiebusch  

E-Print Network (OSTI)

Muon reconstruction with AMANDA Christopher Wiebusch DESY IfH Platanenallee 6, 15738 Zeuthen, Germany Abstract This document describes the method of muon track reconstruction in AMANDA. #12; 1 particles such as muons. Clearly identified up­going muon tracks are a key signature for charged current

Wiebusch, Christopher

346

General Geometry CT Reconstruction Alexei Ramotar  

E-Print Network (OSTI)

, reconstruction, Filtered Back Projection Submitted to IPCV'06 Abstract We present an efficient and accurate acquired by a parallel-beam CT scanner. Once in that form, Filtered Back Projection can be used to perform technology that uses many small x-ray images to reconstruct a view of the internal structures of an object

Orchard, Jeffery J.

347

Fast Globally Convergent Reconstruction in Emission Tomography  

E-Print Network (OSTI)

considerable speedup by using only a subset of the projection data per sub- iteration. However, OSEM1 Fast Globally Convergent Reconstruction in Emission Tomography Using COSEM, an Incremental EM globally convergent incremental EM algorithms for reconstruction in emission tomography, COSEM- ML

Rangarajan, Anand

348

Compact D-D Neutron Source-Driven Subcritical Multiplier and Beam-Shaping Assembly for Boron Neutron Capture Therapy  

SciTech Connect

This work assesses the feasibility of using a small, safe, and inexpensive keff 0.98 subcritical fission assembly [subcritical neutron multiplier (SCM)] to amplify the treatment neutron beam intensity attainable from a compact deuterium-deuterium (D-D) fusion neutron source delivering [approximately]1012 n/s. The objective is to reduce the treatment time for deep-seated brain tumors to [approximately]1 h. The paper describes the optimal SCM design and two optimal beam-shaping assemblies (BSAs) - one designed to maximize the dose rate and the other designed to maximize the total dose that can be delivered to a deep-seated tumor. The neutron beam intensity amplification achieved with the optimized SCM and BSA results in an increase in the treatment dose rate by a factor of 18: from 0.56 Gy/h without the SCM to 10.1 Gy/h. The entire SCM is encased in an aluminum structure. The total amount of 20% enriched uranium required for the SCM is 8.5 kg, and the cost (not including fabrication) is estimated to be less than $60,000. The SCM power level is estimated at 400 W when driven by a 1012 n/s D-D neutron source. This translates into consumption of only [approximately]0.6% of the initially loaded 235U atoms during 50 years of continuous operation and implies that the SCM could operate continuously for the entire lifetime of the facility without refueling. Cooling the SCM does not pose a challenge; it may be accomplished by natural circulation as the maximum heat flux is only 0.034 W/cm2.

Francesco Ganda; Jasmina Vujic; Ehud Greenspan; Ka-Ngo Leung

2010-12-01T23:59:59.000Z

349

Corrosion resistant neutron absorbing coatings  

DOE Patents (OSTI)

A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

Choi, Jor-Shan (El Cerrito, CA); Farmer, Joseph C. (Tracy, CA); Lee, Chuck K. (Hayward, CA); Walker, Jeffrey (Gaithersburg, MD); Russell, Paige (Las Vegas, NV); Kirkwood, Jon (Saint Leonard, MD); Yang, Nancy (Lafayette, CA); Champagne, Victor (Oxford, PA)

2012-05-29T23:59:59.000Z

350

Corrosion resistant neutron absorbing coatings  

DOE Patents (OSTI)

A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

Choi, Jor-Shan; Farmer, Joseph C; Lee, Chuck K; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

2013-11-12T23:59:59.000Z

351

Passive Neutron Detection at Borders  

SciTech Connect

Radiation portal monitor systems have been deployed to screen for illicit trafficking of radioactive materials at international border crossings. This report reviews some of the neutron detection requirements and capabilities of passive detection systems used for such applications. Simulations show the effects of cargo materials on neutron spectra, different detector geometries, using a large-array of neutron detectors, and the effects of backgrounds including “ship effect” neutrons.

Kouzes, Richard T.; Siciliano, Edward R.; Ely, James H.; Keller, Paul E.; McConn, Ronald J.

2008-03-01T23:59:59.000Z

352

Neutron phase echo  

Science Journals Connector (OSTI)

The coherent overlap of the waves traversing the two legs of a perfect-crystal neutron interferometer is altered by a material with a neutron-nuclear optical potential. The fringe visibility is limited by the longitudinal coherence length. The loss of interference contrast caused by a slab of material of positive optical potential can be restored by placing another slab of material with a negative optical potential in the same leg of the interferometer. This paper describes the observation and detailed characterization of this quantum-mechanical phenomenon, which we call the phase-echo effect.

R. Clothier; H. Kaiser; S. A. Werner; H. Rauch; H. Wölwitsch

1991-11-01T23:59:59.000Z

353

Inelastic Neutron Scattering Instrumentation  

Science Journals Connector (OSTI)

Abstract Inelastic neutron scattering spectroscopy spans an enormous energy range, which is equivalent to a wide range of timescales. It is convenient to divide the whole energy range into three sectors, while recognising that there is significant overlap between them. In the lowest energy range, ± 10 meV the applications are principally quasielastic scattering and tunneling spectroscopy. The second range, 0–1000 meV covers the regions of vibrational spectroscopy and magnetic excitations. The highest range above 1000 meV is the province of neutron Compton scattering. The instrumentation used in each of these energy regimes is described.

S.F. Parker

2014-01-01T23:59:59.000Z

354

Equilibrium Reconstruction on the Large Helical Device  

SciTech Connect

Equilibrium reconstruction is commonly applied to axisymmetric toroidal devices. Recent advances in computational power and equilibrium codes have allowed for reconstructions of three-dimensional fields in stellarators and heliotrons. We present the first reconstructions of finite beta discharges in the Large Helical Device (LHD). The plasma boundary and magnetic axis are constrained by the pressure profile from Thomson scattering. This results in a calculation of plasma beta without a-priori assumptions of the equipartition of energy between species. Saddle loop arrays place additional constraints on the equilibrium. These reconstruction utilize STELLOPT, which calls VMEC. The VMEC equilibrium code assumes good nested flux surfaces. Reconstructed magnetic fields are fed into the PIES code which relaxes this constraint allowing for the examination of the effect of islands and stochastic regions on the magnetic measurements.

Samuel A. Lazerson, D. Gates, D. Monticello, H. Neilson, N. Pomphrey, A. Reiman S. Sakakibara, and Y. Suzuki

2012-07-27T23:59:59.000Z

355

Calcium sensitivity determinations by neutron activation analysis as applied to bone  

E-Print Network (OSTI)

. ated, eliminating a total body dose. But primarily, the ettuipment used is greatly reduced in size and cost froa~ praY. . ou" roric?u. in' a poa tai~lc neutron aource (againat t', u uacs of a cyclo' ton) aad on1 y onu acinti llatf on cry tnl...PII(IILiL'1 of r il 'lto. l Iir, 'L 'v;il'(i(i', N ~ ? - (1-e ) &5 Nc& i a e(5uation 1 N ? null&'~er of radioactive atoms present at end of irradiation (atoms) - neutron flux (neutrons/cm 'sec) 2. N . - total nuAer of orig" nal atoms (atoms) 1 ? decay...

Blasdel, Michael John

2012-06-07T23:59:59.000Z

356

Neutron Bombardment of Counting Diamonds  

Science Journals Connector (OSTI)

21 February 1956 research-article Neutron Bombardment of Counting Diamonds A. H...Examination was also made of the effect of neutron bombardment on pulse-height distribution...additional charge traps produced by the neutrons. The layered crystal texture disclosed...

1956-01-01T23:59:59.000Z

357

NOTES ON NEUTRON DEPTH PROFILING  

E-Print Network (OSTI)

NOTES ON NEUTRON DEPTH PROFILING by J.K. Shultis Department of Mechanical and Nuclear Engineering College of Engineering Kansas State University Manhattan, Kansas 66506 Dec. 2003 #12;Notes on Neutron Depth Profiling J. Kenneth Shultis December 2003 1 Introduction The purpose of neutron depth profiling

Shultis, J. Kenneth

358

Neutron - Mirror Neutron Oscillations: How Fast Might They Be?  

E-Print Network (OSTI)

We discuss the phenomenological implications of the neutron (n) oscillation into the mirror neutron (n'), a hypothetical particle exactly degenerate in mass with the neutron but sterile to normal matter. We show that the present experimental data allow a maximal n-n' oscillation in vacuum with a characteristic time $\\tau$ much shorter than the neutron lifetime, in fact as small as 1 sec. This phenomenon may manifest in neutron disappearance and regeneration experiments perfectly accessible to present experimental capabilities and may also have interesting astrophysical consequences, in particular for the propagation of ultra high energy cosmic rays.

Zurab Berezhiani; Luis Bento

2005-07-03T23:59:59.000Z

359

Scission neutron emission and prompt fission neutron spectrum  

E-Print Network (OSTI)

The mass, energy and angular integrated spectra of prompt fission neutrons for sup 2 sup 3 sup 5 U induced fission in the energy range from thermal to 5 MeV were analyzed. It allows assume that about 0.362+-0.025 neutrons per fission are emitted due to another mechanism then neutron emission from excited fragments after full acceleration. The spectrum of scission neutrons consists of two components with average energy 0.98 MeV and 2.74 MeV. The share of scission neutrons and their spectrum shape estimated in this work does not contradict to results of differential experiments analyzed in previous papers.

Kornilov, N V

2001-01-01T23:59:59.000Z

360

Apparent Neutron Emissions from Polyethylene Capsules during Neutron Activation and Delayed Neutron Counting  

Science Journals Connector (OSTI)

At Imperial College uranium is determined at very low levels in environmental samples by delayed neutron counting. High density polyethylene capsules are used ... transfer system, from the reactor, to the neutron

R. Benzing; N. M. Baghini; B. A. Bennett…

2000-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Low Dose Radiation Program: 2010 Low Dose Radiation Research Program  

NLE Websites -- All DOE Office Websites (Extended Search)

Low Dose Radiation Research Program Investigators' Workshop Low Dose Radiation Research Program Investigators' Workshop »» Event Slide Show More than 150 people attended this year's workshop, held April 12-14 at the Renaissance M Street Hotel in Washington, D.C. In addition to 34 plenary talks and more than 70 poster presentations made by the program investigators, participants heard guest speakers from the National Cancer Institute and from sister low-dose programs in Europe and Japan. Remarks from DOE Dr. Anna Palmisano, Associate Director, Office of Science, Director for Biological and Environmental Research (BER), welcomed the meeting participants, thanked Low Dose Radiation Research Program Manager Dr. Noelle Metting for her leadership, and acknowledged the importance of the Low Dose Program to DOE because of its unique focus and important role. She

362

SciTech Connect: 2010 Neutron Review: ORNL Neutron Sciences Progress...  

Office of Scientific and Technical Information (OSTI)

117; GREENHOUSE GASES; HEAVY ION ACCELERATORS; HELIUM 3; HFIR REACTOR; IRON; JINR; MAGNETIC FIELDS; NEUTRON DETECTORS; NEUTRON SOURCES; NEUTRONS; ORNL; RELIABILITY;...

363

Neutron Absorbing Alloys  

DOE Patents (OSTI)

The present invention is drawn to new classes of advanced neutron absorbing structural materials for use in spent nuclear fuel applications requiring structural strength, weldability, and long term corrosion resistance. Particularly, an austenitic stainless steel alloy containing gadolinium and less than 5% of a ferrite content is disclosed. Additionally, a nickel-based alloy containing gadolinium and greater than 50% nickel is also disclosed.

Mizia, Ronald E. (Idaho Falls, ID); Shaber, Eric L. (Idaho Falls, ID); DuPont, John N. (Whitehall, PA); Robino, Charles V. (Albuquerque, NM); Williams, David B. (Bethlehem, PA)

2004-05-04T23:59:59.000Z

364

Proton-Neutron Scattering  

Science Journals Connector (OSTI)

Using Glauber multiple-scattering theory, the missing-mass spectrum for protons scattered off a deuterium target is computed. The relatively clean separation of the single- and double-scattering peaks offers the possibility of determining the high-energy proton-neutron differential cross section.

N. Straumann and C. Wilkin

1970-03-02T23:59:59.000Z

365

Optimization of neutron source  

SciTech Connect

I consider here the optimization of the two component neutron source, allowing beam species and energy to vary. A simple model is developed, based on the earlier publications, that permits the optimum to be obtained simply. The two component plasma, with one species of hot ion (D{sup +} or T{sup +}) and the complementary species of cold ion, is easy to analyze in the case of a spatially uniform cold plasma, as to good approximation the total number of hot ions is important but not their spatial distribution. Consequently, the optimization can ignore spatial effects. The problem of a plasma with both types of hot ions and cold ions is rather more difficult, as the neutron production by hot-hot interactions is sensitive to their spatial distributions. Consequently, consideration of this problem will be delayed to a future memorandum. The basic model is that used in the published articles on the two-component, beam-plasma mirror source. I integrate the Fokker-Planck equation analytically, obtaining good agreement with previous numerical results. This simplifies the optimization, by providing a functional form for the neutron production. The primary result is expressed in terms of the power efficiency: watts of neutrons/watts of primary power. The latter includes the positive ion neutralization efficiency. At 150 keV, the present model obtains an efficiency of 0.66%, compared with 0.53% of the earlier calculation.

Hooper, E.B.

1993-11-09T23:59:59.000Z

366

Solid state neutron detector array  

DOE Patents (OSTI)

A neutron detector array is capable of measuring a wide range of neutron fluxes. The array includes multiple semiconductor neutron detectors. Each detector has a semiconductor active region that is resistant to radiation damage. In one embodiment, the array preferably has a relatively small size, making it possible to place the array in confined locations. The ability of the array to detect a wide range of neutron fluxes is highly advantageous for many applications such as detecting neutron flux during start up, ramp up and full power of nuclear reactors.

Seidel, John G. (Pittsburgh, PA); Ruddy, Frank H. (Monroeville, PA); Brandt, Charles D. (Mount Lebanon, PA); Dulloo, Abdul R. (Pittsburgh, PA); Lott, Randy G. (Pittsburgh, PA); Sirianni, Ernest (Monroeville, PA); Wilson, Randall O. (Greensburg, PA)

1999-01-01T23:59:59.000Z

367

Ramsey Experiments Using Neutron Beams  

Science Journals Connector (OSTI)

Abstract Ramsey's technique of separated oscillatory fields adapted to cold neutron beams is a very sensitive method to probe for spin- dependent interactions of neutrons with magnetic and pseudomagnetic fields. In the last couple of years several distinctive experiments using this technique have been performed, e.g. to determine the incoherent neutron scattering length of the deuteron, to perform polarized neutron imaging of magnetic fields and samples, and lately, to search for new light spin-1 bosons. Here, some of these results are reviewed and possible future measurements with respect to a pulsed neutron source are presented.

Florian M. Piegsa

2014-01-01T23:59:59.000Z

368

SNS | Spallation Neutron Source | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

SNS SNS Instruments Working with SNS Contact Us User Program Manager Laura Morris Edwards 865.574.2966 Spallation Neutron Source Home | User Facilities | SNS SNS | Spallation Neutron Source SHARE SNS is an accelerator-based neutron source in Oak Ridge, Tennessee, USA. This one-of-a-kind facility provides the most intense pulsed neutron beams in the world for scientific research and industrial development. The 80-acre SNS site is located on Chestnut Ridge and is part of Oak Ridge National Laboratory. Although most people don't know it, neutron scattering research has a lot to do with our everyday lives. For example, things like medicine, food, electronics, and cars and airplanes have all been improved by neutron scattering research. Neutron research also helps scientists improve materials used in a

369

Estimation of thyroid doses received by the population of Belarus as a result of the Chernobyl accident  

SciTech Connect

Within weeks of the Chernobyl accident ABOUT 300,000 measurements of human thyroidal iodine-131 content were conducted in the more contaminated areas of Belarus. Results of these and other measurements form the basis of thyroid-dose reconstruction for the residents. For Class 1 (measured dose), individual doses are estimated directly from measured thyroidal iodine content plus information on life style and dietary habits. Such estimates are available for about 130,000 individuals from Gomel and Mogilev Oblasts and Minsk City. For Class 2 (passport doses), every settlement with a sufficient number of residents with measured doses, individual thyroid-dose distributions were determined for several age groups and levels of milk consumption. A population of about 2.7 million resides in the passport settlements.

Gavrilin, Y.; Khrouch, V.; Shinkarev, S. [Institut Biofiziki, Moscow (Russian Federation); Drozdovitch, V.; Minenko, V.; Shemyakina, E. [Institute of Radiation Medicine, Minsk (Belarus); Bouville, A. [National Cancer Inst., Rockville, MD (United States); Anspaugh, L. [Lawrence Livermore National Lab., CA (United States)

1996-02-01T23:59:59.000Z

370

Neutron drops and neutron pairing energy  

Science Journals Connector (OSTI)

The ground state energy of a six-neutron drop is computed with variational and Green’s function Monte Carlo methods using the Argonne v18 two-nucleon and the Urbana three-nucleon potentials. Combined with earlier results from investigations of the drops 8n and 7n, this energy gives a 1p-shell pairing energy of (1.8±0.4) MeV. The generalized Skyrme effective interaction discussed in the earlier work is applied to these nuclei by calculating, for the open-shell drops 7n and 6n, the matrix elements of the Skyrme t matrix directly for the states involved. The pairing energy obtained is 1.50 MeV, in reasonable agreement with the accurate calculations.

A. Smerzi; D. G. Ravenhall; V. R. Pandharipande

1997-11-01T23:59:59.000Z

371

Search for neutron - mirror neutron oscillations in a laboratory experiment with ultracold neutrons  

E-Print Network (OSTI)

Mirror matter is considered as a candidate for dark matter. In connection with this an experimental search for neutron - mirror neutron (nn') transitions has been carried out using storage of ultracold neutrons in a trap with different magnetic fields. As a result, a new limit for the neutron - mirror neutron oscillation time has been obtained, tau_osc >= 448 s (90% C.L.), assuming that there is no mirror magnetic field larger than 100 nT. Besides a first attempt to obtain some restriction for mirror magnetic field has been done.

A. P. Serebrov; E. B. Aleksandrov; N. A. Dovator; S. P. Dmitriev; A. K. Fomin; P. Geltenbort; A. G. Kharitonov; I. A. Krasnoschekova; M. S. Lasakov; A. N. Murashkin; G. E. Shmelev; V. E. Varlamov; A. V. Vassiljev; O. M. Zherebtsov; O. Zimmer

2008-09-29T23:59:59.000Z

372

Impact of Internal Metallic Ports in Temporary Tissue Expanders on Postmastectomy Radiation Dose Distribution  

SciTech Connect

Purpose: Temporary tissue expanders (TTE) with an internal magnetic metal port (IMP) have been increasingly used for breast reconstruction in post-mastectomy patients who receive radiation therapy (XRT). We evaluated XRT plans of patients with IMP to determine its effect on XRT dose distribution. Methods and Materials: Original treatment plans with CT simulation scans of 24 consecutive patients who received XRT (ORI), planned without heterogeneity corrections, to a reconstructed breast containing an IMP were used. Two additional treatment plans were then generated: one treatment plan with the IMP assigned the electron density of the rare earth magnet, nickel plated neodymium-iron-boron (HET), and a second treatment plan with the IMP assigned a CT value of 1 to simulate a homogeneous breast without an IMP (BRS). All plans were prescribed 50 Gy to the reconstructed breast (CTV). Results: CTV coverage by 50 Gy was significantly lower in the HET (mean 87.7% CTV) than in either the ORI (mean 99.7% CTV, P<.001) or BRS plans (mean 95.0% CTV, P<.001). The effect of the port was more pronounced on CT slices containing the IMP with prescription dose coverage of the CTV being less in the HET than in either ORI (mean difference 33.6%, P<.01) or BRS plans (mean difference 30.1%, P<.001). HET had a less homogeneous and conformal dose distribution than BRS or ORI. Conclusion: IMPs increase dose heterogeneity and reduce dose to the breast CTV through attenuation of the beam. For optimal XRT treatment, heterogeneity corrections should be used in XRT planning for patients with TTE with IMP, as the IMP impacts dose distribution.

Chen, Susie A.; Ogunleye, Tomiwa; Dhabbaan, Anees [Department of Radiation Oncology, Winship Cancer Institute, Emory University, Atlanta, Georgia (United States)] [Department of Radiation Oncology, Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Huang, Eugene H. [North Coast Cancer Care, Sandusky, Ohio (United States)] [North Coast Cancer Care, Sandusky, Ohio (United States); Losken, Albert [Division of Plastic Surgery and Reconstructive Surgery, Department of Surgery, Emory University, Atlanta, Georgia (United States)] [Division of Plastic Surgery and Reconstructive Surgery, Department of Surgery, Emory University, Atlanta, Georgia (United States); Gabram, Sheryl [Division of Surgical Oncology, Department of Surgery, Emory University, Atlanta, Georgia (United States)] [Division of Surgical Oncology, Department of Surgery, Emory University, Atlanta, Georgia (United States); Davis, Lawrence [Department of Radiation Oncology, Winship Cancer Institute, Emory University, Atlanta, Georgia (United States)] [Department of Radiation Oncology, Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Torres, Mylin A., E-mail: matorre@emory.edu [Department of Radiation Oncology, Winship Cancer Institute, Emory University, Atlanta, Georgia (United States)

2013-03-01T23:59:59.000Z

373

Low Dose Radiation Research Program: Low-Dose Dose-Response of  

NLE Websites -- All DOE Office Websites (Extended Search)

Low-Dose Dose-Response of Proliferating Human Cells Exposed to Low Low-Dose Dose-Response of Proliferating Human Cells Exposed to Low Dose Rate g-Radiation. Authors: Louise Enns,1 Michael Weinfeld,1 Albert Murtha,1 and Kenneth Bogen2 Institutions: 1Cross Cancer Institute and 2Lawrence Livermore National Laboratory. Clinical and environmental exposure to ionizing radiation rarely exceeds 200 cGy. To examine cell proliferation at early times (up to 5 days) post-irradiation, we are utilizing an assay in which single cells encapsulated within ~30- to 70-µm-diameter agarose gel microdrops (GMDs) are exposed and cultured for 4 days at 37°C, then analyzed by flow cytometry (FC). Clonogenic proliferation is measured as the fraction of occupied GMDs containing multicellular microcolonies after 4 days in culture. This assay was applied to human A549 lung cells exposed to gamma

374

Parallel Lumigraph Reconstruction PeterPike Sloan  

E-Print Network (OSTI)

Lake City, UT 84112 hansen@cs.utah.edu Abstract This paper presents three techniques for reconstructing/1056 Redmond WA 98052 ppsloan@microsoft.com Charles Hansen Dept of Computer Science University of Utah Salt

Utah, University of

375

Precision Muon Reconstruction in Double Chooz  

E-Print Network (OSTI)

We describe a muon track reconstruction algorithm for the reactor anti-neutrino experiment Double Chooz. The Double Chooz detector consists of two optically isolated volumes of liquid scintillator viewed by PMTs, and an Outer Veto above these made of crossed scintillator strips. Muons are reconstructed by their Outer Veto hit positions along with timing information from the other two detector volumes. All muons are fit under the hypothesis that they are through-going and ultrarelativistic. If the energy depositions suggest that the muon may have stopped, the reconstruction fits also for this hypothesis and chooses between the two via the relative goodness-of-fit. In the ideal case of a through-going muon intersecting the center of the detector, the resolution is ~40 mm in each transverse dimension. High quality muon reconstruction is an important tool for reducing the impact of the cosmogenic isotope background in Double Chooz.

Abe, Y; Barriere, J C; Baussan, E; Bekman, I; Bergevin, M; Bezerra, T J C; Bezrukov, L; Blucher, E; Buck, C; Busenitz, J; Cabrera, A; Caden, E; Camilleri, L; Carr, R; Cerrada, M; Chang, P -J; Chauveau, E; Chimenti, P; Collin, A P; Conover, E; Conrad, J M; Crespo-Anadón, J I; Crum, K; Cucoanes, A; Damon, E; Dawson, J V; Dietrich, D; Djurcic, Z; Dracos, M; Elnimr, M; Etenko, A; Fallot, M; von Feilitzsch, F; Felde, J; Fernandes, S M; Fischer, V; Franco, D; Franke, M; Furuta, H; Gil-Botella, I; Giot, L; Göger-Neff, M; Gonzalez, L F G; Goodenough, L; Goodman, M C; Grant, C; Haag, N; Hara, T; Haser, J; Hofmann, M; Horton-Smith, G A; Hourlier, A; Ishitsuka, M; Jochum, J; Jollet, C; Kaether, F; Kalousis, L N; Kamyshkov, Y; Kaplan, D M; Kawasaki, T; Kemp, E; de Kerret, H; Kryn, D; Kuze, M; Lachenmaier, T; Lane, C E; Lasserre, T; Letourneau, A; Lhuillier, D; Lima, H P; Lindner, M; no, J M López-Casta; LoSecco, J M; Lubsandorzhiev, B; Lucht, S; Maeda, J; Mariani, C; Maricic, J; Martino, J; Matsubara, T; Mention, G; Meregaglia, A; Miletic, T; Milincic, R; Minotti, A; Nagasaka, Y; Nikitenko, Y; Novella, P; Obolensky, M; Oberauer, L; Onillon, A; Osborn, A; Palomares, C; Pepe, I M; Perasso, S; Pfahler, P; Porta, A; Pronost, G; Reichenbacher, J; Reinhold, B; Röhling, M; Roncin, R; Roth, S; Rybolt, B; Sakamoto, Y; Santorelli, R; Schilithz, A C; Schönert, S; Schoppmann, S; Shaevitz, M H; Sharankova, R; Shimojima, S; Sibille, V; Sinev, V; Skorokhvatov, M; Smith, E; Spitz, J; Stahl, A; Stancu, I; Stokes, L F F; Strait, M; Stüken, A; Suekane, F; Sukhotin, S; Sumiyoshi, T; Sun, Y; Svoboda, R; Terao, K; Tonazzo, A; Thi, H H Trinh; Valdiviesso, G; Vassilopoulos, N; Veyssiere, C; Vivier, M; Wagner, S; Watanabe, H; Wiebusch, C; Winslow, L; Wurm, M; Yang, G; Yermia, F; Zimmer, V

2014-01-01T23:59:59.000Z

376

Neutrino energy reconstruction problems and neutrino oscillations  

E-Print Network (OSTI)

We discuss the accuracy of the usual procedure for neutrino energy reconstruction which is based on the quasielastic kinematics. Our results are described in terms of a probability distribution for a real neutrino energy value. Several factors are responsible of the deviations from the reconstructed value. The main one is the multinucleon component of the neutrino interaction which in the case of Cherenkov detectors enters as a quasielastic cross section, increasing the mean neutrino energy which can differ appreciably from the reconstructed value. As an application we derive, for excess electron events attributed to the conversion of muon neutrinos, the true neutrino energy distribution based on the experimental one which is given in terms of the reconstructed value. The result is a reshaping effect. For MiniBooNE the low energy peak is suppressed and shifted at higher energies, which may influence the interpretation in terms of oscillation. For T2K at the Super Kamiokande far detector the reshaping translat...

Martini, M; Chanfray, G

2012-01-01T23:59:59.000Z

377

HDRMC, an accelerated Monte Carlo dose calculator for high dose rate brachytherapy with CT-compatible applicators  

SciTech Connect

Purpose: To present a new accelerated Monte Carlo code for CT-based dose calculations in high dose rate (HDR) brachytherapy. The new code (HDRMC) accounts for both tissue and nontissue heterogeneities (applicator and contrast medium). Methods: HDRMC uses a fast ray-tracing technique and detailed physics algorithms to transport photons through a 3D mesh of voxels representing the patient anatomy with applicator and contrast medium included. A precalculated phase space file for the{sup 192}Ir source is used as source term. HDRM is calibrated to calculated absolute dose for real plans. A postprocessing technique is used to include the exact density and composition of nontissue heterogeneities in the 3D phantom. Dwell positions and angular orientations of the source are reconstructed using data from the treatment planning system (TPS). Structure contours are also imported from the TPS to recalculate dose-volume histograms. Results: HDRMC was first benchmarked against the MCNP5 code for a single source in homogenous water and for a loaded gynecologic applicator in water. The accuracy of the voxel-based applicator model used in HDRMC was also verified by comparing 3D dose distributions and dose-volume parameters obtained using 1-mm{sup 3} versus 2-mm{sup 3} phantom resolutions. HDRMC can calculate the 3D dose distribution for a typical HDR cervix case with 2-mm resolution in 5 min on a single CPU. Examples of heterogeneity effects for two clinical cases (cervix and esophagus) were demonstrated using HDRMC. The neglect of tissue heterogeneity for the esophageal case leads to the overestimate of CTV D90, CTV D100, and spinal cord maximum dose by 3.2%, 3.9%, and 3.6%, respectively. Conclusions: A fast Monte Carlo code for CT-based dose calculations which does not require a prebuilt applicator model is developed for those HDR brachytherapy treatments that use CT-compatible applicators. Tissue and nontissue heterogeneities should be taken into account in modern HDR brachytherapy planning.

Chibani, Omar, E-mail: omar.chibani@fccc.edu; C-M Ma, Charlie [Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States)] [Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111 (United States)

2014-05-15T23:59:59.000Z

378

Santo Antonio de Tanna? story and reconstruction  

E-Print Network (OSTI)

SANTO ANTONIO DE TANNÁ: STORY AND RECONSTRUCTION A Thesis by TIAGO MIGUEL FRAGA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF ARTS... December 2007 Major Subject: Anthropology SANTO ANTONIO DE TANNÁ: STORY AND RECONSTRUCTION A Thesis by TIAGO MIGUEL FRAGA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment...

Fraga, Tiago Miguel

2008-10-10T23:59:59.000Z

379

First neutron generation in the BINP accelerator based neutron source  

Science Journals Connector (OSTI)

Pilot innovative facility for neutron capture therapy was built at Budker Institute of Nuclear Physics, Novosibirsk. This facility is based on a compact vacuum insulation tandem accelerator designed to produce proton current up to 10 mA. Epithermal neutrons are proposed to be generated by 1.915 MeV protons bombarding a lithium target using 7Li(p,n)7Be threshold reaction. The results of the first experiments on neutron generation are reported and discussed.

B. Bayanov; A. Burdakov; V. Chudaev; A. Ivanov; S. Konstantinov; A. Kuznetsov; A. Makarov; G. Malyshkin; K. Mekler; I. Sorokin; Yu. Sulyaev; S. Taskaev

2009-01-01T23:59:59.000Z

380

Protein crystallography with spallation neutrons: the user facility at Los Alamos Neutron Science Center  

Science Journals Connector (OSTI)

The protein crystallography user facility at the neutron spallation source run by Los Alamos Neutron Science Center is described.

Langan, P.

2004-01-17T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Neutron electric polarizability  

E-Print Network (OSTI)

We use the background field method to extract the "connected" piece of the neutron electric polarizability. We present results for quenched simulations using both clover and Wilson fermions and discuss our experience in extracting the mass shifts and the challenges we encountered when we lowered the quark mass. For the neutron we find that as the pion mass is lowered below $500\\MeV$, the polarizability starts rising in agreement with predictions from chiral perturbation theory. For our lowest pion mass, $m_\\pi=320\\MeV$, we find that $\\alpha_n = 3.8(1.3)\\times 10^{-4}\\fm^3$, which is still only one third of the experimental value. We also present results for the neutral pion; we find that its polarizability turns negative for pion masses smaller than $500\\MeV$ which is puzzling.

Andrei Alexandru; Frank X. Lee

2009-11-13T23:59:59.000Z

382

Artificial Production of Neutrons  

Science Journals Connector (OSTI)

A porcelain vacuum tube capable of producing currents of positive ions up to 30 microamperes and with energies up to 106 electron-volts has been constructed and used for artificial disintegration experiments. Neutrons have been produced by bombarding beryllium with helium ions, and by bombarding lithium and beryllium with the ions of the heavy isotope of hydrogen. The curve obtained for the efficiency of production of neutrons by helium ions as a function of voltage is in agreement with the curve obtained by a downward extrapolation of curves known from work with polonium ?-particles. The present paper is mainly a discussion of the apparatus and methods of measurement, since brief reports of the results have already been presented.

H. R. Crane; C. C. Lauritsen; A. Soltan

1934-04-15T23:59:59.000Z

383

Coherence of neutron fields  

Science Journals Connector (OSTI)

Glauber's definition of quantum coherence is used for neutron fields under the assumption that the complete occupation number space is a direct product of Fermi subspaces. As a result, completely coherent microfields are obtained which define a density operator in full analogy to Glauber's P representation of boson fields. For better physical significance, a transformation from the P representation to a momentum representation is performed. It is proved that the second-order coherence function in this representation is equivalent to Wolf's second-order coherence function of a classical Dirac field. Finally, the results of the theory are used to calculate explicitly the second-order coherence function and the coherence time of an ideally collimated neutron beam.

E. Ledinegg and E. Schachinger

1983-05-01T23:59:59.000Z

384

Fast neutron imaging device and method  

DOE Patents (OSTI)

A fast neutron imaging apparatus and method of constructing fast neutron radiography images, the apparatus including a neutron source and a detector that provides event-by-event acquisition of position and energy deposition, and optionally timing and pulse shape for each individual neutron event detected by the detector. The method for constructing fast neutron radiography images utilizes the apparatus of the invention.

Popov, Vladimir; Degtiarenko, Pavel; Musatov, Igor V.

2014-02-11T23:59:59.000Z

385

Spallation Neutron Sources Around the World  

E-Print Network (OSTI)

Spallation Neutron Sources Around the World Bernie Riemer Thanks to others for the many shamelessly Laboratory #12;2 Managed by UT-Battelle for the U.S. Department of Energy Spallation Neutron Source Facilities Spallation Neutron Source Facilities Serve Neutron Science Programs · Neutron beams to suites

McDonald, Kirk

386

Di-neutron correlation in light neutron-rich nuclei  

E-Print Network (OSTI)

Using a three-body model with density-dependent contact interaction, we discuss the root mean square distance between the two valence neutrons in $^{11}$Li nuclues as a function of the center of mass of the neutrons relative to the core nucleus $^9$Li. We show that the mean distance takes a pronounced minimum around the surface of the nucleus, indicating a strong surface di-neutron correlation. We demonstrate that the pairing correlation plays an essential role in this behavior. We also discuss the di-neutron structure in the $^8$He nucleus.

K. Hagino; H. Sagawa; P. Schuck

2008-12-03T23:59:59.000Z

387

REVIEW OF NON-NEUTRON AND NEUTRON NUCLEAR DATA, 2004.  

SciTech Connect

Review articles are in preparation for the 2004 edition of the CRC Handbook of Chemistry and Physics dealing with the evaluation of both non-neutron and neutron nuclear data. Data on the discovery of element 110, Darmstadtium, and element 111 have been officially accepted, while data on element 11 8 have been withdrawn. Data to be presented include revised values for very short-lived nuclides, long-lived nuclides and beta-beta decay measurements. There has been a reassessment of the spontaneous fission (sf) half-lives, which distinguishes between sf decay half-lives and cluster decay half-lives and with cluster-fission decay. New measurements of isotopic abundance values for many elements will be discussed with an emphasis on the minor isotopes of interest for use in neutron activation analysis measurements. Neutron resonance integrals will be discussed emphasizing the differences between the calculated values obtained from the analytical integration over neutron resonances and the measured values in a neutron reactor-spectrum, which does not quite conform to the assumed 1/E neutron energy spectrum. The method used to determine the neutron resonance integral from measurement, using neutron activation analysis, will be discussed.

HOLDEN, N.E.

2004-09-26T23:59:59.000Z

388

Review of Non?Neutron and Neutron Nuclear Data, 2004  

Science Journals Connector (OSTI)

Review articles are in preparation for the 2004 edition of the CRC Handbook of Chemistry and Physics dealing with the evaluation of both non?neutron and neutron nuclear data. Data on the discovery of element 110 Darmstadtium and element 111 have been officially accepted while data on element 118 have been withdrawn. Data to be presented include revised values for very short?lived nuclides long?lived nuclides and beta?beta decay measurements. There has been a reassessment of the spontaneous fission (sf) half?lives which distinguishes between sf decay half?lives and cluster decay half?lives and with cluster?fission decay. New measurements of isotopic abundance values for many elements will be discussed with an emphasis on the minor isotopes of interest for use in neutron activation analysis measurements. Neutron resonance integrals will be discussed emphasizing the differences between the calculated values obtained from the analytical integration over neutron resonances and the measured values in a neutron reactor?spectrum which does not quite conform to the assumed 1/E neutron energy spectrum. The method used to determine the neutron resonance integral from measurement using neutron activation analysis will be discussed.

Norman E. Holden

2005-01-01T23:59:59.000Z

389

Hubble Sees a Neutron Star Alone in Space Nearest Known Neutron Star  

E-Print Network (OSTI)

Hubble Sees a Neutron Star Alone in Space Nearest Known Neutron Star #12;Birth of a Neutron Star In the core, nuclei are smashed into protons & neutrons; the protons combine with electrons to make neutrons & neutrinos. The birth temperature of a neutron star is ~5Ã?1011 K, but neutrino emission cools it to `only

Barnes, Joshua Edward

390

Microdosimetric considerations in the use of the boron neutron capture reaction in radiation therapy  

Science Journals Connector (OSTI)

This thesis attempts to further the understanding of the dosimetric and microdosimetric aspects of the boronneutron capture reaction (BNCR) in two distinct radiation therapy modalities the conventional BNCT and boronneutron capture enhanced fast neutron therapy (BNCEFNT). The absorbed dose in these two modalities consists of contributions from gamma rays neutrons and the neutron capture reactions in tissue including the BNCR. The use of low pressure tissue equivalent proportional counters for the dual purpose of dosimetry and microdosimetry of the complex radiation fields used in BNCT and BNCEFNT has been thoroughly investigated. Commercially obtained paired 1/2? Rossi type LET counters (with and without boron-10 in the A-150 TEP wall) were used in this work. The counters were dose calibrated by positioning the proton edge in the measured spectra at a lineal energy of 150 keV/micrometer. Using this paired counter technique the gamma neutron and BNCR dose components in different radiation fields were resolved. Experimental results indicate that this technique is well suited for the dosimetry of BNCT and BNCEFNT fields. The uncertainties in these dose measurements are smaller than or comparable to those achieved using conventional techniques. The microdosimetric spectra measured by the proportional counters have been found to be useful for evaluating the quality of these radiation fields.

Chandrasekhar Kota

1997-01-01T23:59:59.000Z

391

Neutron diffraction study of decaborane  

Science Journals Connector (OSTI)

Neutron diffraction study of decaborane ... The Molecular Structure of (PSH+)(nido-7,8-C2B9H12-) Determined by Neutron Diffraction (PS = Proton Sponge, 1,8-Bis(dimethylamino)naphthalene) ... The Molecular Structure of (PSH+)(nido-7,8-C2B9H12-) Determined by Neutron Diffraction (PS = Proton Sponge, 1,8-Bis(dimethylamino)naphthalene) ...

Armin Tippe; Walter C. Hamilton

1969-03-01T23:59:59.000Z

392

Neutron Imaging by Boric Acid  

E-Print Network (OSTI)

In this paper a new type of passive neutron detector based on the already existing one, CR39, is described. Its operation was verified by three different neutron sources: an Americium-Beryllium (Am241-Be) source; a TRIGA type nuclear reactor; and a fast neutron reactor called TAPIRO. The obtained results, reported here, positively confirm its operation and the accountability of the new developed detecting technique.

Fabio Cardone; Giovanni Cherubini; Walter Perconti; Andrea Petrucci; Alberto Rosada

2013-02-22T23:59:59.000Z

393

Los Alamos Neutron Science Center  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Science Center gets capacity boost December 2, 2010 Los Alamos National Security funds upgrade to key facility LOS ALAMOS, New Mexico, December 2, 2010-The National Nuclear...

394

Neutron diffraction by perfect crystals  

Science Journals Connector (OSTI)

The dynamical theory of neutron diffraction has been formulated to include the reflected waves from the boundaries of a crystal. This formulation allows a unified treatment of the neutron optical and diffraction phenomena in crystals. It is shown that the neutron propagation in the crystal is determined by two structure factors characterizing the lattice: the total structure factor and the structure factor of the neutron-spin-neutron-orbit interaction. Diffraction by a parallel crystal plate has been studied in considerable detail. It has been found that for a definite neutron-spin orientation, the diffracted and transmitted beams are modulated by six terms periodic in the thickness of the crystal. The period of the dominant term, in this Pendellösung fringe structure, has been calculated in several cases of experimental importance. If the glancing angle of incidence substantially exceeds the critical angle for total reflection, the results are identical with those obtained by a simple extension, to the neutron case, of the x-ray dynamical theory. The diffraction by a magnetized crystal has been examined in some detail and it is shown that measurement of the Pendellösung periods for the two neutron-spin orientations may be used to determine both the nuclear and magnetic neutron scattering amplitude.

C. Stassis and J. A. Oberteuffer

1974-12-15T23:59:59.000Z

395

CHRPR Neutron Board Replacement Manual  

SciTech Connect

This document will walk through the steps to exchange the neutron channel boards with gamma channel boards in the CHRPR box.

Erikson, Rebecca L.; Myjak, Mitchell J.

2013-03-31T23:59:59.000Z

396

Supporting Organizations | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

support the researchers and maintain the instruments used across all of our neutron science research: Biology and Soft Matter Division The Biology and Soft Matter...

397

LANSCE | Lujan Neutron Scattering Center  

NLE Websites -- All DOE Office Websites (Extended Search)

Lujan Center Data Management Lujan Neutron Scattering Center Logo The Lujan Center within LANSCE utilizes a pulsed source and has a complement of 15 instruments. It maintains a...

398

Scattering of Neutrons by Lead  

Science Journals Connector (OSTI)

... THE University of Cambridge cyclotron and neutron velocity selector have been used for studying the ... velocity selector have been used for studying the scattering of ...

R. LATHAM; J. M. CASSELS

1948-02-21T23:59:59.000Z

399

Combined neutron reflectometry and rheology  

Science Journals Connector (OSTI)

Neutron reflectometry is combined with rheology in order to reveal the near surface structure of liquids and polymers under well defined deformation.

Wolff, M.

2013-10-26T23:59:59.000Z

400

Inelastic neutron scattering study on bioprotectant systems  

Science Journals Connector (OSTI)

...22 December 2005 Inelastic neutron scattering study on bioprotectant systems...UK We collected inelastic neutron scattering (INS) spectra of homologous...vibrational properties|neutron scattering| 1. Introduction In recent...

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Neutron scattering from adsorbed polymer layers  

Science Journals Connector (OSTI)

Neutron scattering from adsorbed polymer layers ... Small-Angle Neutron Scattering Study of Cyclic Poly(ethylene glycol) Adsorption on Colloidal Particles ... Small-Angle Neutron Scattering Study of Cyclic Poly(ethylene glycol) Adsorption on Colloidal Particles ...

Terence Cosgrove; Timothy G. Heath; Keith Ryan; Trevor L. Crowley

1987-11-01T23:59:59.000Z

402

Protein structures by spallation neutron crystallography  

Science Journals Connector (OSTI)

The capabilities of the Protein Crystallography Station at Los Alamos Neutron Science Center for determining protein structures by spallation neutron crystallography are illustrated, and the methodological and technological advances that are emerging from the Macromolecular Neutron Crystallography consortium are described.

Langan, P.

2008-04-18T23:59:59.000Z

403

Inelastic Neutron Scattering from Glass Formers  

Science Journals Connector (OSTI)

......research-article Articles Inelastic Neutron Scattering from Glass Formers U. Buchenau...transition. Coherent inelastic neutron scattering data indicate a mixture of...Supplement No. 126, 1997 Inelastic Neutron Scattering from Glass Formers U. BUCHENAU......

U. Buchenau

1997-01-01T23:59:59.000Z

404

Quasiclassical Approximation for Slow Neutron Scattering  

Science Journals Connector (OSTI)

......Approximation for Slow Neutron Scattering Takeo Nishigori Department...formula for the differential scattering cross section of a slow neutron is derived along the line...of Spherical Rotors and Neutron Scattering Juichiro Hama and Tuto......

Takeo Nishigori

1970-06-01T23:59:59.000Z

405

Neutron scattering in concrete and wood  

Science Journals Connector (OSTI)

......Article Computational techniques Neutron scattering in concrete and wood A. Facure...library were used to simulate the neutron scattering in barriers of conventional...of the barrier thickness on neutron scattering factors is also being studied......

A. Facure; A. X. Silva; R. C. Falcão; V. R. Crispim

2006-09-01T23:59:59.000Z

406

Neutron-deuteron breakup and quasielastic scattering  

E-Print Network (OSTI)

Quasielastic scattering and deuteron breakup in the 200 MeV region is studied by impinging a pulsed neutron beam on a deuterium target at the Weapons Neutron Research facility at the Los Alamos Neutron Science Center. The ...

Ohlson, Alice Elisabeth

2009-01-01T23:59:59.000Z

407

Neutron Scattering in ORNL'S Calibration Facility  

Science Journals Connector (OSTI)

......Dosimetry Article Neutron Scattering in ORNL'S Calibration...C. Francis Room scattering corrections for several common neutron detectors in a new...and enclosed room scattering situations are compared...good. A personnel neutron spectrometer was......

J.C. Liu; C.S. Sims; W.H. Casson; H. Murakami; C. Francis

1991-01-01T23:59:59.000Z

408

Neutron Generators for Spent Fuel Assay  

E-Print Network (OSTI)

13, 2010. [11] D-D Neutron Generator Development at LBNL, J.12] High-yield DT Neutron Generator, B.A. Ludewigt et al. ,a Compact High-Yield Neutron Generator, O. Waldmann and B.

Ludewigt, Bernhard A

2011-01-01T23:59:59.000Z

409

NEUTRON EMISSION IN RELATIVISTIC NUCLEAR COLLISIONS  

E-Print Network (OSTI)

Figure Captions Figure l. Neutron-to-proton ratio at 30° labapparent anomalies in the neutron-to-proton fragment ratio.3 proton data. Figure 2. Neutron-to-proton ratio R 1 , Solid

Stevenson, J.D.

2013-01-01T23:59:59.000Z

410

PRACTICAL NEUTRON DOSIMETRY AT HIGH ENERGIES  

E-Print Network (OSTI)

and Chupp, E. L. "Cosmic Ray Neutron Energy Spectrum." Phys.Study of Cosmic-Ray Neutrons." National Aero­ nautics andStudy of Cosmic-Ray Neutrons: Mid-Latitude Flights." Health

McCaslin, J.B.

2010-01-01T23:59:59.000Z

411

Neutron Generators for Spent Fuel Assay  

E-Print Network (OSTI)

of a High Fluence Neutron Source for NondestructiveAugust 8-13, 2010. [11] D-D Neutron Generator Development at2005. [12] High-yield DT Neutron Generator, B.A. Ludewigt et

Ludewigt, Bernhard A

2011-01-01T23:59:59.000Z

412

Neutron Activation Analysis of Archaeological Artefacts  

Science Journals Connector (OSTI)

17 December 1970 research-article Neutron Activation Analysis of Archaeological...have been determined by non-destructive neutron activation analysis. Examples are given...1971065519 applications archaeology neutron activation analysis radioactivity 1969...

1970-01-01T23:59:59.000Z

413

Extracting buried twists with polarized neutron reflectometry  

Science Journals Connector (OSTI)

Polarized neutron reflectometry can extract the depth-dependent magnetization of ... the surface. Measuring the reflectivity first with neutrons glancing off the front surface and again with neutrons glancing off...

K.V. O’Donovan; J.A. Borchers; C.F. Majkrzak; O. Hellwig…

2002-12-01T23:59:59.000Z

414

Simultaneous usage of pinhole and penumbral apertures for imaging small scale neutron sources from inertial confinement fusion experiments  

SciTech Connect

Inertial confinement fusion experiments at the National Ignition Facility are designed to understand the basic principles of creating self-sustaining fusion reactions by laser driven compression of deuterium-tritium (DT) filled cryogenic plastic capsules. The neutron imaging diagnostic provides information on the distribution of the central fusion reaction region and the surrounding DT fuel by observing neutron images in two different energy bands for primary (13-17 MeV) and down-scattered (6-12 MeV) neutrons. From this, the final shape and size of the compressed capsule can be estimated and the symmetry of the compression can be inferred. These experiments provide small sources with high yield neutron flux. An aperture design that includes an array of pinholes and penumbral apertures has provided the opportunity to image the same source with two different techniques. This allows for an evaluation of these different aperture designs and reconstruction algorithms.

Guler, N.; Volegov, P.; Danly, C. R.; Grim, G. P.; Merrill, F. E.; Wilde, C. H. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States)

2012-10-15T23:59:59.000Z

415

Ground-water contribution to dose from past Hanford Operations  

SciTech Connect

The Hanford Environmental Dose Reconstruction (HEDR) Project is being conducted to estimate radiation doses that populations and individuals could have received from Hanford Site operations from 1944 to the present. Four possible pathways by which radionuclides migrating in ground water on the Hanford Site could have reached the public have been identified: (1) through contaminated ground water migrating to the Columbia River; (2) through wells on or adjacent to the Hanford Site; (3) through wells next to the Columbia River downstream of Hanford that draw some or all of their water from the river (riparian wells); and (4) through atmospheric deposition resulting in contamination of a small watershed that, in turn, results in contamination of a shallow well or spring by transport in the ground water. These four pathways make up the ground-water pathway,'' which is the subject of this study. Assessment of the ground-water pathway was performed by (1) reviewing the existing extensive literature on ground water and ground-water monitoring at Hanford and (2) performing calculations to estimate radionuclide concentrations where no monitoring data were collected. Radiation doses that would result from exposure to these radionuclides were calculated.

Freshley, M.D.; Thorne, P.D.

1992-08-01T23:59:59.000Z

416

Measuring the Neutron Lifetime Using Magnetically Trapped Neutrons  

E-Print Network (OSTI)

The neutron beta-decay lifetime plays an important role both in understanding weak interactions within the framework of the Standard Model and in theoretical predictions of the primordial abundance of 4He in Big Bang Nucleosynthesis. In previous work, we successfully demonstrated the trapping of ultracold neutrons (UCN) in a conservative potential magnetic trap. A major upgrade of the apparatus is nearing completion at the National Institute of Standards and Technology Center for Neutron Research (NCNR). In our approach, a beam of 0.89 nm neutrons is incident on a superfluid 4He target within the minimum field region of an Ioffe-type magnetic trap. A fraction of the neutrons is downscattered in the helium to energies <200 neV, and those in the appropriate spin state become trapped. The inverse process is suppressed by the low phonon density of helium at temperatures less than 200 mK, allowing the neutron to travel undisturbed. When the neutron decays the energetic electron ionizes the helium, producing scintillation light that is detected using photomultiplier tubes. Statistical limitations of the previous apparatus will be alleviated by significant increases in field strength and trap volume resulting in twenty times more trapped neutrons.

C. M. O'Shaughnessy; R. Golub; K. W. Schelhammer; C. M. Swank; P. -N. Seo; P. R. Huffman; S. N. Dzhosyuk; C. E. H. Mattoni; L. Yang; J. M. Doyle; K. J. Coakley; A. K. Thompson; H. P. Mumm; S. K. Lamoreaux; G. Yang

2009-03-31T23:59:59.000Z

417

Low-Energy Neutron-Neutron Scattering Parameters  

Science Journals Connector (OSTI)

A precise evaluation of the spectrum in the reaction ?-+D?2n+?, including final-state interactions is presented with a view of determining the neutron-neutron scattering length. Approximations of previous calculations are examined and avoided where their effect is found to be significant. Sufficiently accurate experiments should be capable of distinguishing this parameter to an error of 1 F.

Myron Bander

1964-06-08T23:59:59.000Z

418

Neutron scattering from ?-Ce at epithermal neutron energies  

Science Journals Connector (OSTI)

Neutron scattering data, using neutrons of incident energies as high as 2...?-Ce and ?-Ce-like systems such as CeRh2, CeNi2, CeFe2, CeRu2, and many others that point clearly to the substantially localized 4f elec...

A. P. Murani

2008-10-01T23:59:59.000Z

419

Slow neutron leakage spectra from spallation neutron sources  

SciTech Connect

An efficient technique is described for Monte Carlo simulation of neutron beam spectra from target-moderator-reflector assemblies typical of pulsed spallation neutron sources. The technique involves the scoring of the transport-theoretical probability that a neutron will emerge from the moderator surface in the direction of interest, at each collision. An angle-biasing probability is also introduced which further enhances efficiency in simple problems. These modifications were introduced into the VIM low energy neutron transport code, representing the spatial and energy distributions of the source neutrons approximately as those of evaporation neutrons generated through the spallation process by protons of various energies. The intensity of slow neutrons leaking from various reflected moderators was studied for various neutron source arrangements. These include computations relating to early measurements on a mockup-assembly, a brief survey of moderator materials and sizes, and a survey of the effects of varying source and moderator configurations with a practical, liquid metal cooled uranium source Wing and slab, i.e., tangential and radial moderator arrangements, and Be vs CH/sub 2/ reflectors are compared. Results are also presented for several complicated geometries which more closely represent realistic arrangements for a practical source, and for a subcritical fission multiplier such as might be driven by an electron linac. An adaptation of the code was developed to enable time dependent calculations, and investigated the effects of the reflector, decoupling and void liner materials on the pulse shape.

Das, S.G.; Carpenter, J.M.; Prael, R.E.

1980-02-01T23:59:59.000Z

420

Quasifree photoproduction of $?$ mesons off protons and neutrons  

E-Print Network (OSTI)

Differential and total cross sections for the quasifree reactions $\\gamma p\\rightarrow\\eta p$ and $\\gamma n\\rightarrow\\eta n$ have been determined at the MAMI-C electron accelerator using a liquid deuterium target. Photons were produced via bremsstrahlung from the 1.5 GeV incident electron beam and energy-tagged with the Glasgow photon tagger. Decay photons of the neutral decay modes $\\eta\\rightarrow 2\\gamma$ and $\\eta\\rightarrow 3\\pi^0 \\rightarrow 6\\gamma$ and coincident recoil nucleons were detected in a combined setup of the Crystal Ball and the TAPS calorimeters. The $\\eta$-production cross sections were measured in coincidence with recoil protons, recoil neutrons, and in an inclusive mode without a condition on recoil nucleons, which allowed a check of the internal consistency of the data. The effects from nuclear Fermi motion were removed by a kinematic reconstruction of the final-state invariant mass and possible nuclear effects on the quasifree cross section were investigated by a comparison of free and quasifree proton data. The results, which represent a significant improvement in statistical quality compared to previous measurements, agree with the known neutron-to-proton cross-section ratio in the peak of the $S_{11}(1535)$ resonance and confirm a peak in the neutron cross section, which is absent for the proton, at a center-of-mass energy $W = (1670\\pm 5)$ MeV with an intrinsic width of $\\Gamma\\approx 30$ MeV.

A2 Collaboration; D. Werthmüller; L. Witthauer; I. Keshelashvili; P. Aguar-Bartolomé; J. Ahrens; J. R. M. Annand; H. J. Arends; K. Bantawa; R. Beck; V. Bekrenev; A. Braghieri; D. Branford; W. J. Briscoe; J. Brudvik; S. Cherepnya; S. Costanza; B. Demissie; M. Dieterle; E. J. Downie; P. Drexler; L. V. Fil'kov; A. Fix; D. I. Glazier; D. Hamilton; E. Heid; D. Hornidge; D. Howdle; G. M. Huber; I. Jaegle; O. Jahn; T. C. Jude; A. Käser; V. L. Kashevarov; R. Kondratiev; M. Korolija; S. P. Kruglov; B. Krusche; A. Kulbardis; V. Lisin; K. Livingston; I. J. D. MacGregor; Y. Maghrbi; J. Mancell; D. M. Manley; Z. Marinides; M. Martinez; J. C. McGeorge; E. F. McNicoll; V. Metag; D. G. Middleton; A. Mushkarenkov; B. M. K. Nefkens; A. Nikolaev; R. Novotny; M. Oberle; M. Ostrick; P. B. Otte; B. Oussena; P. Pedroni; F. Pheron; A. Polonski; S. N. Prakhov; J. Robinson; G. Rosner; T. Rostomyan; S. Schumann; M. H. Sikora; D. Sober; A. Starostin; I. Supek; M. Thiel; A. Thomas; M. Unverzagt; D. P. Watts

2014-07-25T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Spallation Neutron Source The Spallation Neutron Source (SNS)  

NLE Websites -- All DOE Office Websites (Extended Search)

F/gim F/gim Spallation Neutron Source The Spallation Neutron Source (SNS) gives researchers more detailed informa- tion on the structure and dynamics of physical and biological materials than ever before possible. This accelerator- based facility provides the most intense pulsed neutron beams in the world. Scien- tists are able to count scattered neutrons, measure their energies and the angles at which they scatter, and map their final positions. SNS enables measurements of greater sensitivity, higher speed, higher resolution, and in more complex sample environments than have been possible at existing neutron facilities. Future Growth SNS was designed from the outset to accommodate a second target station, effectively doubling the capacity of the

422

Neutron halo effect on direct neutron capture and photodisintegration  

Science Journals Connector (OSTI)

A novel effect of the neutron halo formation is presented for the direct radiative neutron capture where a p-wave neutron is captured into an s orbit with neutron halo by emitting an E1 ? ray. As an example, an enormous enhancement is demonstrated for the cross section of C12(n,?)13C(1/2+) at low energy in excellent agreement with a recent experiment. The S factor of the final state is evaluated. The inverse process, i.e., photo disintegration is discussed for an example of Be11. A sharp but nonresonant peak near the threshold is obtained as a result of the neutron halo in its anomalous ground state.

T. Otsuka; M. Ishihara; N. Fukunishi; T. Nakamura; M. Yokoyama

1994-05-01T23:59:59.000Z

423

Neutron structure effects in the deuteron and one neutron halos  

E-Print Network (OSTI)

Although the neutron (n) does not carry a total electric charge, its charge and magnetization distributions represented in momentum space by the electromagnetic form factors, $F_1^{(n)} (q^2)$ and $F_2^{(n)} (q^2)$, lead to an electromagnetic potential of the neutron. Using this fact, we calculate the electromagnetic corrections to the binding energy, $B_d$, of the deuteron and a one neutron halo nucleus (11Be), by evaluating the neutron-proton and the neutron-charged core (10Be) potential, respectively. The correction to $B_d$ (~9 keV) is comparable to that arising due to the inclusion of the $\\Delta$-isobar component in the deuteron wave function. In the case of the more loosely bound halo nucleus, 11Be, the correction is close to about 2 keV.

M. Nowakowski; N. G. Kelkar; T. Mart

2005-11-28T23:59:59.000Z

424

Neutron structure effects in the deuteron and one neutron halos  

Science Journals Connector (OSTI)

Although the neutron (n) does not carry a total electric charge, its charge and magnetization distributions represented in momentum space by the electromagnetic form factors, F1(n)(q2) and F2(n)(q2), lead to an electromagnetic potential of the neutron. Using this fact, we calculate the electromagnetic corrections to the binding energy, Bd, of the deuteron and a one-neutron halo nucleus (Be11) by evaluating the neutron-proton and the neutron-charged core (Be10) potential, respectively. The correction to Bd (?9 keV) is comparable to that arising due to the inclusion of the ?-isobar component in the deuteron wave function. In the case of the more loosely bound halo nucleus, Be11, the correction is close to about 2 keV.

M. Nowakowski; N. G. Kelkar; T. Mart

2006-08-28T23:59:59.000Z

425

Neutron beam imaging at neutron spectrometers at Dhruva  

SciTech Connect

A low efficiency, 2-Dimensional Position Sensitive Neutron Detector based on delay line position encoding is developed. It is designed to handle beam flux of 10{sup 6}-10{sup 7} n/cm{sup 2}/s and for monitoring intensity profiles of neutron beams. The present detector can be mounted in transmission mode, as the hardware allows maximum neutron transmission in sensitive region. Position resolution of 1.2 mm in X and Y directions, is obtained. Online monitoring of beam images and intensity profile of various neutron scattering spectrometers at Dhruva are presented. It shows better dynamic range of intensity over commercial neutron camera and is also time effective over the traditionally used photographic method.

Desai, Shraddha S.; Rao, Mala N. [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

2012-06-05T23:59:59.000Z

426

Electroweak bremsstrahlung from neutron-neutron scattering  

Science Journals Connector (OSTI)

Background: Nucleon-nucleon (NN) bremsstrahlung processes NN? (nn?, np?, and pp?) have been extensively investigated. Neutrino-pair bremsstrahlung processes from nucleon-nucleon scattering NN??¯ (nn??¯, np??¯, and pp??¯) have recently attracted attention in studies of neutrino emission in neutron stars. The calculated NN??¯ cross sections (or emissivities) are found to be sensitive to the two-nucleon dynamical model used in the calculations. Purpose and Method: A realistic one-boson-exchange (ROBE) model for NN interactions is used to construct the electroweak bremsstrahlung amplitudes using the well-known nucleon electromagnetic and weak interaction vertices. The constructed nn? and nn??¯ amplitudes are investigated by applying them to calculate nn? and nn??¯ cross sections, respectively. Results: (i) The 190-MeV ROBE nn? cross sections agree well with those calculated using the TuTts amplitude, but they are in disagreement with those calculated using the Low amplitude. (ii) The calculated nn??¯ cross sections using the ROBE amplitude at the neutrino-pair energy ? = 1 MeV are in quantitative agreement with those calculated by Timmermans et al. [Phys. Rev. C 65, 064007 (2002)], who used the leading-order term of the soft neutrino-pair bremsstrahlung amplitude. Conclusions: The nn? amplitude in the ROBE approach, which obeys the soft-photon theorem, has a predictive power similar to that of the TuTts amplitude. The nn??¯ amplitude in the ROBE approach, which is consistent with the soft neutrino-pair bremsstrahlung theorem, has a predictive power similar to that of the soft neutrino-pair bremsstrahlung amplitude of Timmermans et al. in the low neutrino-pair energy region.

Yi Li; M. K. Liou; W. M. Schreiber

2009-09-22T23:59:59.000Z

427

Christmas burst reveals neutron star collision  

NLE Websites -- All DOE Office Websites (Extended Search)

Christmas burst reveals neutron star collision Christmas burst reveals neutron star collision Called the Christmas Burst, GRB 101225A was freakishly lengthy and it produced...

428

High energy neutron Computed Tomography developed  

NLE Websites -- All DOE Office Websites (Extended Search)

objects. May 9, 2014 Neutron tomography horizontal "slice" of a tungsten and polyethylene test object containing tungsten carbide BBs. Neutron tomography horizontal "slice"...

429

Search for: "neutron scattering" | DOE PAGES  

Office of Scientific and Technical Information (OSTI)

neutron scattering" Find + Advanced Search Advanced Search All Fields: "neutron scattering" Title: Full Text: Bibliographic Data: Creator Author: Name Name ORCID Type: All...

430

Scattering of Fast Neutrons by Boron  

Science Journals Connector (OSTI)

The cross section of boron for the scattering of fast neutrons through angles greater than 30° was measured at neutron energies between 0.2 and 3 Mev.

H. H. Barschall; M. E. Battat; W. C. Bright

1946-10-01T23:59:59.000Z

431

Neutron Imaging of Advanced Engine Technologies  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

the development process * Spallation Neutron Source (SNS) - Most intense pulsed neutron beams in the world; energy selective - Multi-laboratory effort funded by DOE Office of...

432

NEUTRON: a program for computing phonon extinction rules of inelastic neutron scattering and thermal diffuse scattering experiments  

Science Journals Connector (OSTI)

NEUTRON is a program for the determination of phonon extinction rules in inelastic neutron scattering experiments.

Kirov, A.K.

2003-07-19T23:59:59.000Z

433

Jet Reconstruction in Heavy Ion Collisions  

E-Print Network (OSTI)

Measurements of strong suppression of inclusive hadron distributions and di-hadron correlations at high $p_{T}$, while providing evidence for partonic energy loss, also suffer from geometric biases due to the competition of energy loss and fragmentation. The measurements of fully reconstructed jets is expected to lack these biases as the energy flow is measured independently of the fragmentation details. In this article, we review the recent results from the heavy ion collisions collected by the STAR experiment at RHIC on direct jet reconstruction utilizing the modern sequential recombination and cone jet reconstruction algorithms together with their background subtraction techniques. In order to assess the jet reconstruction biases a comparison with the jet cross section measurement in $\\sqrt{s}=200$ GeV p+p collisions scaled by the number of binary nucleon-nucleon collisions to account for nuclear geometric effects is performed. Comparison of the inclusive jet cross section obtained in central Au+Au events with that in $p+p$ collisions, published previously by STAR, suggests that unbiased jet reconstruction in the complex heavy ion environment indeed may be possible.

Sevil Salur

2009-05-12T23:59:59.000Z

434

Neutrons from high?energy x?ray medical accelerators: An estimate of risk to the radiotherapy patient  

Science Journals Connector (OSTI)

The problem of neutrons produced by many of the high?energy x?ray therapy machines (10 MV and above) is reviewed and the possible risk their presence poses to radiotherapy patients is estimated. A review of the regulatory background containing a summary of the recommendations of the U. S. Council of State Governments (USCSG) and of the International Electro?Technical Commission (IEC) as well as an indication that recommendations will be forthcoming from the National Council on Radiation Protection (NCRP) and the International Commission of Radiological Protection (ICRP) is presented. The neutrons in question are produced by high?energy photons(x rays) incident on the various materials of the target flattening filter collimators and other essential components of the equipment. The neutron yield (per treatmentdose) increases rapidly as the megavoltage is increased from 10 to 20 MV but remains approximately constant above this. Measurements and calculations of the quantity quality and spatial distribution of these neutrons and their concomitant dose are summarized. Values of the neutrondose are presented as entrance dose midline dose (10?cm depth) and integral dose both within and outside of the treatment volume. These values are much less than the unavoidable photondoses which are largely responsible for treatment side effects. For typical equipment the average neutron integral dose from accelerator?produced neutrons is about 4–7 g?cGy (per treatment cGy) depending on the treatment plan. This translates into an average dose of neutrons [averaged over the body of a typical 70?kg (154 1b) patient] of 0.06–0.10 cGy for a treatment of 1000 cGy. Using these neutrondoses and the best available neutron risk coefficients it is estimated that 50×10? 6 fatal malignancies per year due to the neutrons may follow a typical treatment course of 5000 rads of 25?MV x rays. This is only about 1/60th of the average incidence of malignancies for the general population. Thus the cancer risk to the radiotherapy patient from accelerator?produced neutrons poses an additional risk to the patient that is negligible in comparison.

Ravinder Nath; Edward R. Epp; John S. Laughlin; William P. Swanson; Victor P. Bond

1984-01-01T23:59:59.000Z

435

Superconductivity | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Research Highlights Research Highlights Superconductivity Neutron diffraction reveals semiconducting phase and contributes to new understanding of iron-based superconductors Contact: Huibo Cao New VULCAN tests of Japanese cable for US ITER's central magnet system (2012) Contact: Ke An ARCS maps collaborative magnetic spin behavior in iron telluride (2011) Published Work: "Unconventional Temperature Enhanced Magnetism in Fe1:1Te" Contact: Igor Zaliznyak Doug Scalapino discusses "common thread" linking unconventional superconducting materials (2011) Contact: Douglas Scalapino Materials Engineering Research at SNS Helps International Collaboration on Fusion Energy Scientists and engineers at ORNL are working with the ITER Organization and the Japanese Atomic Energy Agency to resolve issues with a critical

436

The Neutron EDM Experiment  

E-Print Network (OSTI)

The neutron EDM experiment has played an important part over many decades in shaping and constraining numerous models of CP violation. This review article discusses some of the techniques used to calculate EDMs under various theoretical scenarios, and highlights some of the implications of EDM limits upon such models. A pedagogical introduction is given to the experimental techniques employed in the recently completed ILL experiment, including a brief discussion of the dominant systematic uncertainties. A new and much more sensitive version of the experiment, which is currently under development, is also outlined.

P. G. Harris

2007-09-19T23:59:59.000Z

437

On Magnetized Neutron Stars  

E-Print Network (OSTI)

In this work we review the formalism normally used in the literature about the effects of density-dependent magnetic fields on the properties of neutron stars, expose some ambiguities that arise and propose a way to solve the related problem. Our approach uses a different prescription for the calculation of the pressure based on the chaotic field formalism for the stress tensor and also a different way of introducing a variable magnetic field, which depends on the energy density rather than on the baryonic density.

Lopes, Luiz L

2014-01-01T23:59:59.000Z

438

Operation Redwing. Project 2. 52. Neutron-induced soil radioactivity  

SciTech Connect

Soil samples were exposed to neutron radiation from Shot Cherokee to help establish the importance of neutron-induced residual gamma radiation. After exposure and recovery, the samples had no detectable activity because the slant range to the nearest sample was nearly 3.5 miles, due to an error in bomb drop. After this failure, an experiment was designed in the field for Shot Yuma in order that induced-activity data could be obtained for a soil other than Nevada Test Site soil. Samples of sodium, manganese, and coral sand from Site Sally were exposed above and below the surface at a slant range of 120 yards. The difference between the effects of pure fission and fission-fusion neutron spectra on induced activity in soil was not measured, since the soil samples on Shot Cehrokee were not activated. However, a method for predicting neutron-induced gamma-radiation intensities was tested for coral soil on Shot Yuma. Predicted values were within + or - 50% of induced dose rates inferred from field measurements.

Cowan, M.

1985-09-01T23:59:59.000Z

439

Neutron-Proton Exchange Demonstrated  

Science Journals Connector (OSTI)

Neutron-Proton Exchange Demonstrated ... EVIDENCE of the exchange of charge between protons and neutrons has recently been obtained from studies in the high power cyclotron, according to Ernest O. Lawrence, professor of physics at the University of California a* Berkeley. ...

1947-11-03T23:59:59.000Z

440

Physics of Neutron Star Crusts  

E-Print Network (OSTI)

The physics of neutron star crusts is vast, involving many different research fields, from nuclear and condensed matter physics to general relativity. This review summarizes the progress, which has been achieved over the last few years, in modeling neutron star crusts, both at the microscopic and macroscopic levels. The confrontation of these theoretical models with observations is also briefly discussed.

N. Chamel; P. Haensel

2008-12-20T23:59:59.000Z

Note: This page contains sample records for the topic "neutron dose reconstruction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Incoherent Neutron Scattering by Polycrystals  

Science Journals Connector (OSTI)

General expressions are given for the first terms in the expansion in powers of the neutron to nuclear mass ratio of the total cross section for incoherent scattering of neutrons by polycrystals. Special limiting cases of these expressions had been published earlier.

G. Placzek

1957-02-15T23:59:59.000Z

442

Neutron Technologies for Bioenergy Research  

SciTech Connect

Neutron scattering is a powerful technique that can be used to probe the structures and dynamics of complex systems. It can provide a fundamental understanding of the processes involved in the production of biofuels from lignocellulosic biomass. A variety of neutron scattering technologies are available to elucidate both the organization and deconstruction of this complex composite material and the associations and morphology of the component polymers and the enzymes acting on them, across multiple length scales ranging from Angstroms to micrometers and time scales from microseconds to picoseconds. Unlike most other experimental techniques, neutron scattering is uniquely sensitive to hydrogen (and its isotope deuterium), an atom abundantly present throughout biomass and a key effector in many biological, chemical, and industrial processes for producing biofuels. Sensitivity to hydrogen, the ability to replace hydrogen with deuterium to alter scattering levels, the fact that neutrons cause little or no direct radiation damage, and the ability of neutrons to exchange thermal energies with materials, provide neutron scattering technologies with unique capabilities for bioenergy research. Further, neutrons are highly penetrating, making it possible to employ sample environments that are not suitable for other techniques. The true power of neutron scattering is realized when it is combined with computer simulation and modeling and contrast variation techniques enabled through selective deuterium labeling.

Langan, Paul [ORNL

2012-01-01T23:59:59.000Z

443

Coherence lengths and neutron optics  

Science Journals Connector (OSTI)

The dynamical diffraction of divergent beams and its application to neutron interferometry are considered. The coherence properties of thermal neutrons are studied, and it is shown that the extreme anisotropy of dynamically diffracted wave packets should be included in the discussion of coherence lengths. Finally, the mechanism leading to a nondispersive phase shift is investigated.

D. Petrascheck

1987-05-01T23:59:59.000Z

444

Neutron imaging for geothermal energy systems  

SciTech Connect

Geothermal systems extract heat energy from the interior of the earth using a working fluid, typically water. Three components are required for a commercially viable geothermal system: heat, fluid, and permeability. Current commercial electricity production using geothermal energy occurs where the three main components exist naturally. These are called hydrothermal systems. In the US, there is an estimated 30 GW of base load electrical power potential for hydrothermal sites. Next generation geothermal systems, named Enhanced Geothermal Systems (EGS), have an estimated potential of 4500 GW. EGSs lack in-situ fluid, permeability or both. As such, the heat exchange system must be developed or engineered within the rock. The envisioned method for producing permeability in the EGS reservoir is hydraulic fracturing, which is rarely practiced in the geothermal industry, and not well understood for the rocks typically present in geothermal reservoirs. High costs associated with trial and error learning in the field have led to an effort to characterize fluid flow and fracturing mechanisms in the laboratory to better understand how to design and manage EGS reservoirs. Neutron radiography has been investigated for potential use in this characterization. An environmental chamber has been developed that is suitable for reproduction of EGS pressures and temperatures and has been tested for both flow and precipitations studies with success for air/liquid interface imaging and 3D reconstruction of precipitation within the core.

Bingham, Philip R [ORNL; Anovitz, Lawrence {Larry} M [ORNL; Polsky, Yarom [ORNL

2013-01-01T23:59:59.000Z

445

Kinetic equilibrium reconstruction on EAST tokamak  

Science Journals Connector (OSTI)

Plasma equilibrium is an important basis for tokamak plasma research. The equilibrium reconstructed from experimental diagnostics is a key element for experiments analysis and for theory study. The kinetic equilibrium has the profiles information (current or safety factor profile, kinetic pressure profile), which are key issues for some studies of physics. With the constraints of magnetic measurements, pressure profile and edge current profile, we achieved the first reconstructed kinetic equilibrium on EAST tokamak. The pressure and edge current profiles are based on the diagnostics and theoretical bootstrap current model. The kinetic equilibrium has the pedestal structure for H-mode plasma, which the magnetic reconstruction missed. This improved equilibrium is an important basis for some experimental analysis and theory studies on EAST.

G Q Li; Q L Ren; J P Qian; L L Lao; S Y Ding; Y J Chen; Z X Liu; B Lu; Q Zang

2013-01-01T23:59:59.000Z

446

Multi-threaded Event Reconstruction with JANA  

SciTech Connect

The C++ reconstruction framework JANA has been written to support the next generation of Nuclear Physics experiments at Jefferson Lab in anticipation of the 12GeV upgrade. The JANA framework was designed to allow multi-threaded event processing with a minimal impact on developers of reconstruction software. As we enter the multi-core (and soon many-core) era, thread-enabled code will become essential to utilizing the full processor power available without invoking the logistical overhead of managing many individual processes. Event-based reconstruction lends itself naturally to mutli-threaded processing. Emphasis will be placed on the multi-threading features of the framework. Test results of the scaling of event processing rates with number of threads are presented.

David Lawrence

2007-09-01T23:59:59.000Z

447

Robust statistical reconstruction for charged particle tomography  

DOE Patents (OSTI)

Systems and methods for charged particle detection including statistical reconstruction of object volume scattering density profiles from charged particle tomographic data to determine the probability distribution of charged particle scattering using a statistical multiple scattering model and determine a substantially maximum likelihood estimate of object volume scattering density using expectation maximization (ML/EM) algorithm to reconstruct the object volume scattering density. The presence of and/or type of object occupying the volume of interest can be identified from the reconstructed volume scattering density profile. The charged particle tomographic data can be cosmic ray muon tomographic data from a muon tracker for scanning packages, containers, vehicles or cargo. The method can be implemented using a computer program which is executable on a computer.

2013-10-08T23:59:59.000Z

448

7 - Estimation of Radiation Doses  

Science Journals Connector (OSTI)

Abstract Radiation doses to the Japanese population from inhalation of contaminated air, external irradiation, terrestrial and marine food contamination are estimated and compared with other sources of anthropogenic (global fallout, Chernobyl accident), natural (radionuclides in food, cosmic radiation) and medical applications (X-ray tests, CT-tests, etc.) of ionizing radiation. The estimated doses from inhalation, ingestion of terrestrial and marine food, and radiation exposure from radioactive clouds and deposited radionuclides were generally below the levels which could cause health damage of the Japanese population, as well as of the world population. The estimated total radiation doses to fish and shellfish in coastal waters during the largest radionuclide releases were by a factor of 10 lower than the baseline safe level postulated for the marine organisms, therefore no harmful effects are expected for the marine ecosystem as well.

Pavel P. Povinec; Katsumi Hirose; Michio Aoyama

2013-01-01T23:59:59.000Z

449

Neutron Log | Open Energy Information  

Open Energy Info (EERE)

Neutron Log Neutron Log Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Neutron Log Details Activities (4) Areas (4) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Downhole Techniques Exploration Sub Group: Well Log Techniques Parent Exploration Technique: Well Log Techniques Information Provided by Technique Lithology: if used in conjunction with other logs, this technique can provide information on the rock type and the porosity Stratigraphic/Structural: Corelation of rock units Hydrological: Estimate of formation porosity Thermal: Dictionary.png Neutron Log: The neutron log responds primarily to the amount of hydrogen in the formation which is contained in oil, natural gas, and water. The amount of hydrogen can be used to identify zones of higher porosity.

450

Scattering of Neutrons by Deuterons  

Science Journals Connector (OSTI)

The elastic scattering of neutrons by deuterons is considered for energies small enough so that only the l=0 part of the incident wave is different from the corresponding part of a plane wave. The Breit-Feenberg Hamiltonian is used, assuming the same potential between all pairs of particles. Any possible polarization of the deuteron by the neutron is neglected, although the individual particles in the deuteron are taken into account by an approximate method. This method is capable of including exchange between the two neutrons. When the exchange term is included, the theory gives a cross section for thermal neutrons two to three times greater than observed; the cross section for 2.5 Mev neutrons is slightly greater than observed.

L. I. Schiff

1937-08-01T23:59:59.000Z

451

Bilateral implant reconstruction does not affect the quality of postmastectomy radiation therapy  

SciTech Connect

To determine if the presence of bilateral implants, in addition to other anatomic and treatment-related variables, affects coverage of the target volume and dose to the heart and lung in patients receiving postmastectomy radiation therapy (PMRT). A total of 197 consecutive women with breast cancer underwent mastectomy and immediate tissue expander (TE) placement, with or without exchange for a permanent implant (PI) before radiation therapy at our center. PMRT was delivered with 2 tangential beams + supraclavicular lymph node field (50 Gy). Patients were grouped by implant number: 51% unilateral (100) and 49% bilateral (97). The planning target volume (PTV) (defined as implant + chest wall + nodes), heart, and ipsilateral lung were contoured and the following parameters were abstracted from dose-volume histogram (DVH) data: PTV D{sub 95%} > 98%, Lung V{sub 20}Gy > 30%, and Heart V{sub 25}Gy > 5%. Univariate (UVA) and multivariate analyses (MVA) were performed to determine the association of variables with these parameters. The 2 groups were well balanced for implant type and volume, internal mammary node (IMN) treatment, and laterality. In the entire cohort, 90% had PTV D{sub 95%} > 98%, indicating excellent coverage of the chest wall. Of the patients, 27% had high lung doses (V{sub 20}Gy > 30%) and 16% had high heart doses (V{sub 25}Gy > 5%). No significant factors were associated with suboptimal PTV coverage. On MVA, IMN treatment was found to be highly associated with high lung and heart doses (both p < 0.0001), but implant number was not (p = 0.54). In patients with bilateral implants, IMN treatment was the only predictor of dose to the contralateral implant (p = 0.001). In conclusion, bilateral implants do not compromise coverage of the target volume or increase lung and heart dose in patients receiving PMRT. The most important predictor of high lung and heart doses in patients with implant-based reconstruction, whether unilateral or bilateral, is treatment of the IMNs. Refinement of radiation techniques in reconstructed patients who require comprehensive nodal irradiation is warranted.

Ho, Alice Y., E-mail: hoa1234@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Patel, Nisha [Drexel University College of Medicine, Philadelphia, PA (United States); Ohri, Nisha [Department of Radiation Oncology, Mount Sinai School of Medicine, New York, NY (United States); Morrow, Monica [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Mehrara, Babak J.; Disa, Joseph J.; Cordeiro, Peter G. [Department of Plastic Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Shi, Weiji; Zhang, Zhigang [Department of Biostatistics and Epidemiology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Gelblum, Daphna [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Nerbun, Claire T.; Woch, Katherine M.; Ballangrud, Ase [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); McCormick, Beryl; Powell, Simon N. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

2014-04-01T23:59:59.000Z

452

Measuring the Neutron Lifetime Using Magnetically Trapped Neutrons  

E-Print Network (OSTI)

The neutron beta-decay lifetime plays an important role both in understanding weak interactions within the framework of the Standard Model and in theoretical predictions of the primordial abundance of 4He in Big Bang Nucleosynthesis. In previous work, we successfully demonstrated the trapping of ultracold neutrons (UCN) in a conservative potential magnetic trap. A major upgrade of the apparatus is nearing completion at the National Institute of Standards and Technology Center for Neutron Research (NCNR). In our approach, a beam of 0.89 nm neutrons is incident on a superfluid 4He target within the minimum field region of an Ioffe-type magnetic trap. A fraction of the neutrons is downscattered in the helium to energies <200 neV, and those in the appropriate spin state become trapped. The inverse process is suppressed by the low phonon density of helium at temperatures less than 200 mK, allowing the neutron to travel undisturbed. When the neutron decays the energetic electron ionizes the helium, producing sci...

O'Shaughnessy, C M; Schelhammer, K W; Swank, C M; Seo, P -N; Huffman, P R; Dzhosyuk, S N; Mattoni, C E H; Yang, L; Doyle, J M; Coakley, K J; Thompson, A K; Mumm, H P; Lamoreaux, S K; Yang, G

2009-01-01T23:59:59.000Z

453

Effect of neutron orbitals on the nuclear shape in neutron-deficient and neutron-rich zirconium nuclei  

Science Journals Connector (OSTI)

The neutron-deficient and neutron-rich zirconium nuclei are studied using statistical theory. The deformation dependence of occupation numbers of the neutron orbitals in these nuclei near the Fermi level is investigated. The preference of the neutrons to occupy or vacate a particular orbital is found to contribute a particular shape to the nucleus.

N. Arunachalam; S. Veeraraghavan; A. Mohamed Akbar

1997-08-01T23:59:59.000Z

454

Bioassay and dose measurement in UV disinfection.  

Science Journals Connector (OSTI)

...reactors. Bioassay and dose measurement in UV disinfection...determined as a function of UV dose to prepare a standard...Sewage Spores, Bacterial radiation effects Sterilization...Microbiology Bioassay and Dose Measurement in UV Disinfection...meth- ods of UV dose estimation used in previous studies...

R G Qualls; J D Johnson

1983-03-01T23:59:59.000Z

455

The Neutron-Hydrogen Mass Difference and the Neutron Mass  

Science Journals Connector (OSTI)

Data in the literature leading to the neutron-hydrogen mass difference and the neutron mass are summarized. The disintegration energy of the deuteron together with the HH-D mass spectroscopic doublet separation apparently yields the best value of n-H=0.755±0.016 Mev and a neutron mass of 1.008,941±0.000,02 mass units. Other transmutation-radioactivity cycles check this value. Several inconsistencies in these data and their possible explanation are pointed out. Experiments of interest for improvement in accuracy and reliability of these values are noted.

W. E. Stephens

1947-01-01T23:59:59.000Z

456

Low Dose Radiation Research Program: Glossary  

NLE Websites -- All DOE Office Websites (Extended Search)

Glossary Glossary A B C D E F G H I J K L M N O P Q R S T U V W X Y Z We welcome updates to the glossary. Please send them to Low Dose. A α=β Ratio: A measure of the curvature of the cell survival curve and a measure of the sensitivity of a tissue or tumor to dose fractionation. The dose at which the linear and quadratic components of cell killing are equal. Abscopal Effect: The radiation response in tissue at a distance from the irradiated site invoked by local irradiation. Absorbed Dose Rate: Absorbed dose divided by the time it takes to deliver that dose. High dose rates are usually more damaging to humans and animals than low-dose rates. This is because repair of damage is more efficient when the dose rate is low. Absorbed Dose: The amount of energy deposited in any substance by ionizing

457

RADIATION DOSE FROM CIGARETTE TOBACCO  

Science Journals Connector (OSTI)

The radioactivity in tobacco leaves collected from 15 different regions of Greece before cigarette production was studied in order to estimate the effective dose from cigarette tobacco due to the naturally occurring primordial radionuclides such as 226 Ra and 210 Pb of the uranium series and 228 Ra of the thorium series and/or man?made produced radionuclides such as 137 Cs of Chernobyl origin. Gamma?ray spectrometry was applied using Ge planar and coaxial type detectors of high resolution and high efficiency. It was concluded that the annual effective dose due to inhalation for adults (smokers) for 226 Ra varied from 42.5 to 178.6?? Sv ? y ?1 (average 79.7?? Sv ? y ?1 ) while for 228 Ra from 19.3 to 116.0?? Sv ? y ?1 (average 67.1?? Sv ? y ?1 ) and for 210 Pb from 47.0 to 134.9?? Sv ? y ?1 (average 104.7?? Sv ? y ?1 ) that is the same order of magnitude for each radionuclide. The sum of the effective dose of the three natural radionuclides varied from 151.9 to 401.3?? Sv ? y ?1 (average 251.5?? Sv ? y ?1 ). The annual effective dose from 137 Cs of Chernobyl origin was three orders of magnitude lower as it varied from 70.4 to 410.4? nSv ? y ?1 (average 199.3? nSv ? y ?1 ).

C. Papastefanou

2008-01-01T23:59:59.000Z

458

Neutron capture therapy with deep tissue penetration using capillary neutron focusing  

DOE Patents (OSTI)

An improved method for delivering thermal neutrons to a subsurface cancer or tumor which has been first doped with a dopant having a high cross section for neutron capture. The improvement is the use of a guide tube in cooperation with a capillary neutron focusing apparatus, or neutron focusing lens, for directing neutrons to the tumor, and thereby avoiding damage to surrounding tissue.

Peurrung, Anthony J. (Richland, WA)

1997-01-01T23:59:59.000Z

459

First neutron generation in the BINP accelerator based neutron source B. Bayanova  

E-Print Network (OSTI)

First neutron generation in the BINP accelerator based neutron source B. Bayanova , A. Burdakova c l e i n f o Keywords: Epithermal neutrons Lithium target Neutron capture therapy Tandem accelerator a b s t r a c t Pilot innovative facility for neutron capture therapy was built at Budker

Taskaev, Sergey Yur'evich

460

neutron density. The neutron density (nn) of the source was modeled by solving the simul-  

E-Print Network (OSTI)

neutron density. The neutron density (nn) of the source was modeled by solving the simul- taneousT is the thermal neutron velocity, l is the decay constant, Ns is the s-process abun- dance, bs� is the maxwellian-averaged neutron capture cross-section, and t0 is the average neutron exposure (21). The branching decay of 186Re

West, Stuart

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461

A neutron producing target for BINP accelerator-based neutron source B. Bayanova  

E-Print Network (OSTI)

A neutron producing target for BINP accelerator-based neutron source B. Bayanova , E. Kashaeva b l e i n f o Keywords: Target Lithium Neutron capture therapy Epithermal neutrons a b s t r a c t An innovative accelerator-based neutron source for BNCT has just started operation at the Budker Institute

Taskaev, Sergey Yur'evich

462

The World Neutron Monitor Network as a tool for the study of solar neutrons  

E-Print Network (OSTI)

The World Neutron Monitor Network as a tool for the study of solar neutrons I. G. Usoskin1 , G. A Neutron Monitor Network to detect high-energy solar neutrons is dis- cussed in detail. It is shown that the existing network can be used for the routine detection of intense sporadic solar-neutron events whenever

Paris-Sud XI, Université de

463

Neutron Reflectometers -a bibliography Adrian R. Rennie  

E-Print Network (OSTI)

Neutron Reflectometers - a bibliography Adrian R. Rennie Background A short catalogue of neutron on the evolution of the design of neutron reflectometers. The papers listed in the bibliography are restricted "Gravity Diffractometer" for Ultracold-Neutron Optics' Nuclear Instruments and Methods, 179, (1981), 393

Rennie, Adrian

464

GPUs Neutron Sensitivity Dependence on Data Type  

Science Journals Connector (OSTI)

Graphics Processing Units are very prone to be corrupted by neutrons. Experimental results obtained irradiating the GPU with high energy neutrons show that the input data type has a strong influence on the neutron-induced error-rate of the executed algorithms. ... Keywords: Data types, GPU, Neutron radiation testing, Precision, Reliability

P. Rech, C. Frost, L. Carro

2014-06-01T23:59:59.000Z

465

[sup 3]He neutron detector performance in mixed neutron gamma environments  

SciTech Connect

A test program of the performance of 3He neutron proportional detectors with varying gas pressures, and their response to lligh level gamma-ray exposure in a mixed neutrodgamma environment, ha$ been performed Our intent was to identie the optimal gas pressure to reduce the gamma-ray sensitivity of these detectors. These detectors were manufxtured using materials to minimize their gamma response. Earlier work focused on 3He fill pressures of four atmospheres and above, whereas the present work focuses on a wider range of pressures. Tests have shown that reducing the .filling pressure will M e r increase the gamma-ray dose range in which the detectors can be operated.

Johnson, N. H. (Nathan H.); Beddingfield, D. H. (David H.)

2002-01-01T23:59:59.000Z

466

SUN (re)construction | Open Energy Information  

Open Energy Info (EERE)

SUN (re)construction SUN (re)construction Jump to: navigation, search Logo: SUN (re)construction Name SUN (re)construction Address 1351 Harker Avenue Place Palo Alto, California Zip 94301 Sector Efficiency Product Zero-net and grid-neutral buildings Year founded 2009 Number of employees 1-10 Phone number 805.679.3616 Website http://www.sunreconstruction.c Coordinates 37.446933°, -122.141049° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":37.446933,"lon":-122.141049,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

467

Money Reconstructed: Argentina and Brazil after Hyperinflation  

E-Print Network (OSTI)

Money Reconstructed: Argentina and Brazil after Hyperinflation Jérôme Sgard (Sciences Po / CERI high inflation, money's dual function as a unit of account and a unit of payment are split attempt to rebuild a single, national money. Whereas returning to peso pricing on domestic markets proved

Paris-Sud XI, Université de

468

Wood River Levee Reconstruction, Madison County, IL  

E-Print Network (OSTI)

Wood River Levee Reconstruction, Madison County, IL 25 October 2006 Abstract: The recommended plan provides for flood damage reduction and restores the original degree of protection of the Wood River Levee-federal sponsor is the Wood River Drainage and Levee District. The Wood River Levee System was authorized

US Army Corps of Engineers