... Title : STUDY OF THE ABSOLUTE FLUX AND ENERGY SPECTRUM OF COSMIC RAY NEUTRONS IN THE ATMOSPHERE. ...
DTIC Science & Technology
A method for determination of absolute intensities of gamma-transitions in neutron resonances is developed. It is based on comparing two time-of-flight spectra measured simultaneously: spectrum of capture in the isotope under study and spectrum of neutron...
National Technical Information Service (NTIS)
... source in water and in two aluminum and water mixtures. ... By use of experimentally determined counting efficiencies, absolute saturation activities ...
... Descriptors : (*THERMAL NEUTRONS, NEUTRON SPECTRUM), (*NEUTRON SPECTRUM, THERMAL NEUTRONS), GASES, NEUTRON ...
The neutron spectrum was measured using a combination of foil detectors. The absolute thermal flux was measured with gold foils using a beta-gamma coincidence counting technique; the epithermal spectrum was measured by taking cadmium ratios with three dif...
It was possible to derive and correlate the following baryon properties: (a) absolute values of the magnetic moments, (b) electric and magnetic form factors of proton and neutron, (c) mass spectrum, and (d) decay rates, in a relativistic theory based on t...
... Descriptors : , (*NEUTRON SPECTRUM, REFLECTION), (*THERMAL NEUTRONS, NEUTRON SPECTRUM), CORRECTIONS, WAVE ...
The intensity and spectrum of neutrons leaking out of the earth's atmosphere are calculated by a multigroup diffusion code as a function of latitude and solar cycle. The absolute intensity is obtained from normalization of the calculated flux to measured values in the atmosphere. The calculated ...
Energy Citations Database
The measurement of the reactor resonance neutron flux in the keV range was discussed. A method was given for the study of the neutron spectrum which is based on the preliminary filtration of the flux by the /sup 10/B absorber. The measurement results were reported. The experimental data obtained indicated the deviation of ...
The parameter of an analytical expression for the fast neutron spectrum is determined. The fast neutron spectra in various location of the TR-1 (Cekmece Nuclear Research and Training Reactor) are obtained. Threshold detectors In exp 115 , Ni exp 58 , AL e...
... Accession Number : AD0616613. Title : AN ABSOLUTE MEASUREMENT OF THERMAL NEUTRON ALBEDO FOR SEVERAL MATERIALS. ...
... (Author). Descriptors : (*NEUTRON SPECTRUM, IRON), NEUTRON FLUX, NEUTRON DETECTORS, NEUTRON CROSS SECTIONS, NUMERICAL ...
A new type of neutron spectrometer, called a Magnetic Recoil Spectrometer (MRS), has been built and activated at OMEGA for measurements of the absolute neutron spectrum in the range 6 to 28 MeV, from which ?R, Ti , and Yn can be determined. The entire spectrum is measured simultaneously, so the ...
NASA Astrophysics Data System (ADS)
Nuclear research emulsions (NRE) have been used to characterize the neutron spectrum emitted by the Little-Boy replica. NRE were irradiated at the Little-Boy surface as well as approximately 2m from the center of the Little-Boy replica using polar angles ...
neutron spectrum are presented. In addition, measuring R at the National Ignition Facility (NIF) [G to ignited implosions. To accomplish this, we are also developing an MRS for the NIF. As much of the research and development and instrument optimization of the MRS at OMEGA is directly applicable to the MRS at the NIF
E-print Network
In connection with upgradation of PARR-1 from 9 to 10 MW, the effects of enhanced power on various neutronic parameters have been investigated. These include: neutron energy spectrum, absolute and relative flux, control rod of worth and shutdown margin, f...
In connection with upgrading of PARR-1 from 9 to 10 MW, the effects of enhanced power on various neutronic parameters have been investigated. These include: neutron energy spectrum, absolute and relative flux, control rod worth and shutdown margin, fissio...
... Descriptors : (*NITROGEN, *NEUTRON TRANSPORT THEORY), LIQUEFIED GASES, FAST NEUTRONS, NEUTRON SPECTRUM, NEUTRON ...
The significant sources of photoneutrons within a linear-accelerator treatment head are identified and absolute estimates of neutron production per treatment dose are given for typical components. Measured data obtained at a variety of accelerator installations are presented and compared with these calculations. It is found that the high-Z materials within ...
DOE Information Bridge
A technique for the measurement of neutron spectra which is independent of neutron direction has been studied. The technique consists of measuring all proton tracks in a known volume of type C2 Ilford emulsion, in which shrinkage has been reduced by treating the plates with rosin. By a suitable differentiation of the proton ...
... Descriptors : , CRYSTALS, DETERMINATION, ENERGY, FAST NEUTRONS, NEUTRON FLUX, NEUTRON SPECTRUM, NEUTRONS, NUCLEAR ...
... (Author). Descriptors : (*NEUTRON CROSS SECTIONS, *NEUTRON ACTIVATION), NEUTRON FLUX, NEUTRON SPECTRUM, FOILS(MATERIALS ...
A new type of neutron spectrometer, called a Magnetic Recoil Spectrometer (MRS), has been built and implemented at the OMEGA laser facility [T. R. Boehly. D. L. Brown, R. S. Craxton et al., Opt. Commun. 133, 495 (1997)] for absolute measurements of the neutron spectrum in the range 6 to 30 MeV, from which fuel ...
A neutron spectrometer, called a magnetic recoil spectrometer (MRS), has been built and implemented at the OMEGA laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] for absolute measurements of the neutron spectrum in the range of 6-30 MeV, from which fuel areal density (rhoR), ion temperature ...
PubMed
A neutron spectrometer, called a magnetic recoil spectrometer (MRS), has been built and implemented at the OMEGA laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] for absolute measurements of the neutron spectrum in the range of 6-30 MeV, from which fuel areal density (?R), ion temperature (Ti), ...
Proper assembly of capsule mass, as manifested through evolution of fuel areal density (?R), is fundamentally important for achieving hot-spot ignition planned at the National Ignition Facility (NIF). Experimental information about ?R and ?R asymmetries, Ti and yield is therefore essential for understanding how this assembly occurs. To obtain this information, a neutron ...
The experimental data given in AERE-R 4173 were reevaluated and the absolute value of alpha /sub O/ for Pu/aup 239/ was found to be 0.356 plus or minus 0.013. A number of alphas for a reactor spectrum and for 2200 m/sec neutrons were re-calculated, and some additional possible systematic errors were considered. (auth)
In an effort to characterize the moderators at the Manuel Lujan Center spallation neutron source, Los Alamos, USA, we measured the thermal spectrum and the absolute thermal flux on several of the beamlines. In a second step, we then compared these measurements to results gained from Monte Carlo transport calculations which simulated ...
Absolute absorption cross sections have been measured for exp 232 Th and exp 197 Au for exp 252 Cf spontaneous fission neutrons. Irradiations were performed in an exceptionally low mass source-foil arrangement, providing a ''pure'' spectrum with few corre...
... Accession Number : AD0444592. Title : NEUTRON SPECTRUM OF AN AM-241-BE (ALPHA, NEUTRON) SOURCE. Corporate ...
... Title : THE TRANSPORT OF NEUTRONS THROUGH THE ATMOSPHERE ... energy spectrum per initial neutron as a function of transport time for a ...
... (Author). Descriptors : (*CRYSTAL STRUCTURE, *NEUTRON DIFFRACTION), (*NEUTRON SPECTRUM, INELASTIC SCATTERING), INFRARED ...
... REACTIONS, NEUTRON CROSS SECTIONS, NEUTRON SPECTRUM, PHOTONUCLEAR REACTIONS, CALIFORNIUM, POLONIUM, RADIUM. ...
... Descriptors : *COMPUTER PROGRAMS), *NEUTRON ACTIVATION), (*NEUTRON FLUX, (*NEUTRON SPECTRUM, DETERMINATION), (*FOILS ...
The yields of neutrons produced in photonuclear reactions by a bremsstrahlung-photon-spectrum are analyzed in terms of the multiplicity of neutron production. Approximating the neutron multiplicity as proportional to the photon energy, we derive the integrated photonuclear cross section from the experimental ...
With the help of a time-of-flight spectrometer, the thermal neutron spectrum of a horizontal canal of the WWR-S Reactor was determined. The measured distribution corresponds to a Maxwell function of the form F(t) = at/sup -4/ expSTA-- (t/sub 0//t)/sup 2/!, in which t represents the neutron time of fiight and t/sub 0/ = 1481 ...
We have measured the absolute intensity, and the energy spectrum, and the pulse shapes as function of neutron energy for the IPNS liquid CH/sub 4/ F moderator, at 108 K. We have fitted the spectrum, corrected for attenuation by aluminum in the beam, using a new cutoff function and fitted the pulse shapes to a new ...
... also provides a slowing down spectrum of ... NEUTRON AGE, NEUTRON TRANSPORT THEORY, NEUTRON TRANSPORT THEORY ...
... at the time of these measurements the neutron spectrum is ... by Hess et al (1959) for neutrons of E ... An anomalous increase in the flux of neutrons of E ...
The mass-yield distribution for the neutron-induced fission of /sup 238/U by degraded fission spectrum neutrons with an average energy of 1.52 MeV has been measured radiochemically for 26 mass chains in the region A = 89 to 153. Germanium-lithium gamma-ray spectroscopy coupled with beta-particle counting techniques was used to ...
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 ...
Neutron energy spectra in an 88 cm diameter, 88 cm long lithium tank were measured with the Ben Gurion University experimental setup. In this setup, the lithium tank is separated from the D-T neutron generator by a 120 cm thick paraffin wall with a 6 cm diameter collimator through it, along the axis of the neutron generator and the ...
A 100-mg /sup 252/Cf neutron activation analysis facility is used routinely at the Savannah River Laboratory for multielement analysis of many solid and liquid samples. An absolute analysis technique converts counting data directly to elemental concentration without the use of classical comparative standards and flux monitors. With the totally automated ...
This method covers procedures for determining the energy-fluence spectra of neutron sources used in radiation-hardness testing of electronic semiconductor devices. The type of sources specifically covered by this method are prompt critical assemblies, such as Godiva- or Triga-type reactors, used in either a steady-state or fast-pulse mode. This method is not applicable to ...
The method covers procedures for determining the energy-fluence spectra of neutron sources used in radiation-hardness testing of electronic semiconductor devices. The type of sources specifically covered by this method are prompt critical assemblies, such as Godiva- to Triga-type reactors, used in either a steady-state or fast-pulse mode. The method is not applicable to power ...
The procedures and status of the absolute measurement of the neutron capture cross sections for exp 115 In and exp 232 Th are described. Work on the exp 239 Pu fission fragment anisotropy and absolute measurement of the fast neutron fission cross section ...
An examination of the standard methods of determining the fission cross section shows that the principle sources of error are uncertainties in the spectrum of the incident neutrons, the energy dependence of the cross sections of the material being studied, the thickness of the fission foil, and the value of some reference cross section. A new ...
Prompt fission neutron spectrum measurements at the University of Massachusetts Lowell 5.5 MV Van de Graaff accelerator laboratory require that the neutron detector efficiency be well known over a neutron energy range of 100 keV to 20 MeV. The efficiency of the detector, has been determined for energies greater ...
A preliminary report on the photographic neutron experiment was written Feb. 1, 1951. Since neither the philosophy of the experiment nor the method of carrying it out underwent significant changes after January 1951, the preliminary report is reproduced here as the first three chapters of this report. Chapter 4 outlines the changes which were introduced as well as the expanded ...
The main emphasis of the program are studies of the structure of neutron-rich nuclei and rare electron capture processes. Research topics discussed are: (1) search for a 17 keV neutrino in internal bremsstrahlung spectrum of (sup 125)I; (2) absolute inten...
Measurements at low power are described, the results of which form the basis for the experimentation with reactors of the swimming-pool type. They concern the reactivity changes which occur in the lowering of the regulating rods and in the loading of fuel elements in the reactor. The local dependence of the thermal, epithermal, and fast flux is also considered. The fluxes were measured ...
Absolute measurements of the capture cross section of Rh, Tm, Ir natural, Au, exp 203 Tl, exp 205 Tl and Tl natural were carried out using the integrated spectrum method in the 0.5 to 3.0 MeV neutron energy range. The cross sections are deduced from the c...
-diagnostic techniques. � We are currently developing another MRS on the NIF for simultaneous t f R i t t (T ) d i at the NIF. � We have now reached the point where we can start to doing physics ith th MRS t OMEGAwith at OMEGA and the NIF � Introduction - MRS principle [Efficiency (MRS) and Resolution (EMRS)] � The MRS
A new and improved correction for accidental coincidences has been devised. Comparison of results based on earlier formulations are provided. The differences between the new expression and the frequently used older formulations indicate possible systematically significant discrepancies in some reported experiments, for example, absolute determinations of the ...
... Accession Number : ADA074711. Title : Absolute Calibration of a Uranium - 238 Fast-Neutron Detector. Descriptive Note : Technical note,. ...
... Title : The Energy Spectrum of Leakage Neutrons from a Homogeneous Reactor,. ... monitoring of a possible accidental critical reaction at K-25. ...
... Title : THE ABSORPTION SPECTRUM OF NEUTRON-IRRADIATED SILICON IN THE NEAR INFRARED. Descriptive Note : Journal article,. ...
... neutron distribution. The fast spectrum retains essentially the fission shape with a slight dip in the 3- to 5-MeV range. The ...
Measurements were carried out by the time-of-flight method. In processing the measured distributions, the authors took account of the background of scattered neutrons and gamma quanta as well as delayed fission gamma quanta. At the second stage of the data processing, the authors introduced the correction for the difference of the realistic spectrometer response function from ...
The energies and absolute intensities of prominent peaks in the 0-600 kev region of the gamma-ray spectrum following thermal neutron capture have been measured with a single NaI(Tl) scintillation spectrometer. The elements investigated were rhodium, silver, cadmium, indium, antimony, tellurium, iodine, samarium, europium, gadolinium, ...
The energies and absolute intensities of prominent peaks in the 0-600 kev region of the gamma-ray spectrum following thermal neutron capture have been measured with a single NaI(T1) scintillation spectrometer. The elements investigated were rhodium, silver, cadmium, indium, antimony, tellurium, iodine, samarium, europium, ...
... Descriptors : *Neutron detectors, *Neutron activation, Calibration, Measurement, Neutron flux, Neutron spectrum, Dosage, Radioactive isotopes ...
The cross-sections of the 14N(n,?) 15N and 19F(n,?) 20F reactions were measured by ?-spectroscopy method with the target placed at the end of a neutron guide of the WWR-M reactor (PNPI, Gatchina). The neutron spectrum was measured by the TOF method. The maximum of the spectrum is located at 0.028(2) eV and FWHM is ...
Neutron energy spectra from the T-T fusion reaction were measured by imploding plastic capsules filled with high-purity tritium gas (99.76%). The experiments were performed on the 60-beam, 30-kJ OMEGA Laser Facility at the University of Rochester's Laboratory for Laser Energetics. The neutron spectra were measured using an absolutely ...
The prompt ?-ray spectrum resulting from capture of 2-keV neutrons in natural lead samples was measured using the 2-keV neutron beam facility of the Materials Testing Reactor. Primary capture ?-ray lines resulting from neutron capture in both 204Pb and 207Pb were observed in this spectrum. From ...
We give sufficient conditions for the presence of the absolutely continuous spectrum of a Schroedinger operator on a regular rooted tree without loops (also called regular Bethe lattice or Cayley tree)
... and to measure the spectrum and distribution of terrestrial neutrons ... launches in four attempts; and made neutron background measurements almost ...
The results of a collaborative study to define both the neutron flux and the spectrum more precisely
NASA Technical Reports Server (NTRS)
... Descriptors : *NEUTRON FLUX, *NEUTRON SPECTRUM, MATHEMATICAL MODELS, MEASUREMENT, SCATTERING, COMPUTER ...
A method is proposed to determine the absolute activities of thick $sup 60$Co, $sup 46$Sc, $sup 24$Na, and $sup 58$Co probes which are often used as activation detectors for neutron flux, fluency and spectrum measurements. In this method, activity can be measured by a 4$pi$$beta$-$gamma$ coincidence measurement without an ...
A set of {sup 60} counting standards was prepared using 0.010-in. diameter cobalt wires. Their activities were from 0.212 to 728 {mu}C with a relative accuracy of +-2%, and an absolute accuracy of +-4%. The effective thermal-neutron activation cross section to be used with 0.010-in. diameter cobalt wire for BEPO irradiations was determined by direct ...
... of neutrons from the TRIGA Mark F ... width of the reactor pulse was ... Descriptors : *RESEARCH REACTORS, *NEUTRON SPECTRUM, *NUCLEAR ...
... Descriptors : *NEUTRON FLUX, *NEUTRON SPECTRUM, *NUCLEAR RADIATION SPECTROSCOPY, DETERMINATION, FOILS(MATERIALS ...
... the energy spectrum of neutrons transported from a given ... PROGRAMMING, *ATMOSPHERES, *NEUTRON TRANSPORT THEORY, INTEGRALS ...
... Intro- .duction to the Theory of Neutron Diffusion ... "Fission Neutron Spectrum of ... "Slowing Down of Neutrons by Hydrogenous Moderators." Journal of ...
... Title : THE EXCITATION SPECTRUM OF EPOXY RESINS; NEUTRON DIFFRACTION, SPECIFIC HEAT AND THERMAL CONDUCTIVITY AT LOW ...
... Accession Number : ADA538851. Title : Characterization of the Energy Spectrum at the Indiana University Neutron Source. ...
The depth profile of 152Eu activity induced in a large granite stone pillar by Hiroshima atomic bomb neutrons was calculated by a Monte Carlo N-Particle Transport Code (MCNP). The pillar was on the Motoyasu Bridge, located at a distance of 132 m (WSW) from the hypocenter. It was a square column with a horizontal sectional size of 82.5 cm x 82.5 cm and height of 179 cm. ...
We produced carrier-free, nearly isotopically pure 193Irm from thermal-neutron irradiation of 192Os. From studies of the conversion-electron spectrum, the photon spectrum, and the absolute counting rates, we determined the absolute K, L1, L2, L3, M1, M3, M5, N, and O+P conversion coefficients ...
The spectrum adjustment procedure was extended to simultaneous neutron and gamma spectrum adjustment, and the feasibility of this technique is demonstrated in the analysis of HFIR dosimetry experiments. Conditions in which gamma rays may contribute consid...
Measurements of discrete gamma-ray spectra from neutron-induced reactions on a Be0 sample have been performed using the broad-spectrum neutron spallation source of the WNR facility at LANSCE. Incident neutron energies were determined by the time-of-flight technique. Two high-purity Ge detectors were used to detect ...
