Absolute measurements of weak neutron fluxes were achieved by activated manganese. A scintillation gamma counter calibrated to 4- pi beta-gamma coincidences was used for measuring the absolute activity of Mn/sup 56/. (R.V.J.)

The determination of absolute neutron fluxes by white beam activation of thick gold foils in conjunction with spectral analysis by time-of-flight monitors is described. A numerical integration procedure is presented and the method applied to determining t...

... total and thermal neutron flux of the US Naval Postgraduate School's AGN-201 reactor was determined by neutron activation of thin gold foils. ...

The theoretical principles of neutron density measurements by the activation method are briefly shown. The experimental method consisting in phosphorus activation followed by absolute measurement of its activity in liquid scintillator is described. Some results of measurements in the ...

... source in water and in two aluminum and water mixtures. ... By use of experimentally determined counting efficiencies, absolute saturation activities ...

The Environmental Science Division at Lawrence Livermore Laboratory has in use a system of absolute Instrumental Neutron Activation Analysis (INAA). Basically, absolute INAA is dependent upon the absolute measurement of the disintegration rates of the nuclides produced by ...

... Accession Number : AD0616613. Title : AN ABSOLUTE MEASUREMENT OF THERMAL NEUTRON ALBEDO FOR SEVERAL MATERIALS. ...

The recently completed OMEGA 64 upgrade at the Lab for Laser Energetics (LLE) at the University of Rochester required a recalibration of the DD neutron absolute yield detector. Measurement of DD neutron absolute yield is crucial to determining fuel densities. The method used to measure absolute ...

The neutron emission rate or a Ra- alpha -Be source of the National Research Council was measured by moderating the neutrons in manganese sulfate solution surrounding the source. Some of the thermal neutrons captured in the bath produce manganese-56, and the neutron emission rate is found from an ...

The absolute measurement of neutron emission rate from the whole plasma is a very important diagnostics as a fusion power monitor in fusion experimental devices with D-T or D-T operations. Here measurement techniques of time-resolved and time-integrated absolute neutron emission on the present tokamaks and ITER are ...

The absolute measurement of neutron emission rate from the whole plasma is a very important diagnostics as a fusion power monitor in fusion experimental devices with D-T or D-T operations. Here measurement techniques of time-resolved and time-integrated absolute neutron emission on the present tokamaks and ITER are ...

The experimental procedure which permit the evaluation of the contribution to the neutron flux originated by neutrons with energy lower than 14 MeV during the application of the absolute method when the irradiation geometry ca not be considered as an scat...

Accuracy of 10% is demanded to the absolute fusion measurement on ITER. To achieve this accuracy, a functional combination of several types of neutron measurement subsystem, cross calibration among them, and in situ calibration are needed. Neutron transport calculation shows the suitable calibration source is a DT/DD ...

Accuracy of 10% is demanded to the absolute fusion measurement on ITER. To achieve this accuracy, a functional combination of several types of neutron measurement subsystem, cross calibration among them, and in situ calibration are needed. Neutron transport calculation shows the suitable calibration source is a DT/DD ...

The utilization of the probe activation method for neutron flux measurements is described. The physical basis and the practical methods for the absolute measurements of thermal, resonance, and fast fluxes are explained and illustrated. The performance of such measurements on the Munich Research Reactor is described. ...

The Absolute Neutron Activation Analysis (ANAA) technique was used to determine element concentrations of Cl and Na in blood of healthy group (male and female blood donators), select from Blood Banks at Sao Paulo city, to provide information which can help in diagnosis of patients. This study permitted to perform a discussion about the ...

... Title : STUDY OF THE ABSOLUTE FLUX AND ENERGY SPECTRUM OF COSMIC RAY NEUTRONS IN THE ATMOSPHERE. ...

An absolute calibration of a radium-beryllium neutron source showed the strength to be 1.45 x 10/sup 7/ neutrons/ second. The calibration technique consisted in neutron absorption by a manganese solution with subsequent measurement of the beta activity of the solution. Equations were ...

Neutron diagnostics have been developed for MTF on the field reversed configuration heating experiment (FRCHX) to detect both DD and DT neutrons. We are working with time-integrated activation counting systems for absolute measurements of neutron yields, in the range of 10^6-10^13 ...

A non-destructive method for determination of neutron exposure and constituent concentrations in an object, such as reactor pressure vessel, is based on the observation of characteristic gamma-rays emitted by activation products in the object by using a unique continuous gamma-ray spectrometer. The spectrometer views the object through appropriate ...

The density of neutrons in a standard pile was determined between the zero-energy and the cut-off energy of 1 mm thick cadmium unit using a gold detector. Its absolute activity was measured using a 4 pi beta counter calibrated for 4 pi beta, gamma coincid...

Activation methods for determining the neutron spectral and spatial distributions in swimming-pool research reactors are outlined, The activation cross sections for several nuclides are tabulated in order to compare their usefulness in the flux activation methods. (T.F.H.)

Deuterium-tritium (D-T) neutron generators are used for elemental composition analysis and medical applications. Often composition is determined by examining elemental ratios in which the knowledge of the neutron flux is unnecessary. However, the absolute value of the neutron flux is required when t...

The absolute intensities of 36 ?-rays in the energy range of 292-8579 keV from neutron capture in chlorine were remeasured at the Budapest cold neutron prompt gamma activation analysis facility. The 1% level of accuracy of the nitrogen standard was practically achieved for the relative intensity of most of the 36Cl ...

The absolute neutron yield of the 14 MeV Frascati neutron generator (FNG) is routinely measured by means of the associated alpha-particle method with a silicon surface barrier detector (SSD). This paper describes the work carried out to characterize the neutron source in terms of absolute ...

D T neutron generators are used for elemental composition analysis and medical applications. Often composition is determined by examining elemental ratios in which the knowledge of the neutron flux is unnecessary. However, the absolute value of the neutron flux is required when the generator is used for ...

The interaction of thermal neutrons with a coin shaped detector is discussed in terms of the reaction rate in an infinite sheet of pure absorber irradiated in a void by an isotropic, Maxwell distribution of thermal neutrons. A coincidence method for the evaluation of the decay rate of the neutron induced ...

Over the past year, the cross section project at the University of Michigan has continued activities in two major areas. In the Neutron Experimental Bay, we have been employing a 150 kV Cockcroft-Walton accelerator as a 14 MeV neutron generator in the mea...

Precision measurements of neutron beta decay parameters address basic questions in nuclear and particle physics, astrophysics, and cosmology. As a basic semileptonic decay system, the free neutron plays an important role in understanding the physics of the weak interaction, and improving the precision of the neutron lifetime is ...

Neutron activation cross sections were measured at 195 kev (50 kev energy spread) for about 30 isotopes, bY absolute gamma counting. Absolute calibration was effected by determining the RdTh-D/sub 2/O neutron source strength with a flat response 4 pi graphite sphere ...

For the absolute estimation of the resonance neutron flux by the activation of resonance probes, it is necessary to know the neutron self- screening in the probe in thick probes and in beta counting to know the magnitude of the beta self-absorption. For the determination of these magnitudes a function is ...

Delayed neutrons are emitted by excited nuclei formed in beta decay of fission products called delayed neutron precursors. About 1% of the total neutrons released in fission are delayed neutrons; however, this small fraction plays an important role in nuclear reactor control. The delayed ...

The thermal neutron fluence rate is determined by the gold activation method. The absolute activity of the irradiated gold foil is measured by a 4??-? coincidence counter. Using this method, corrections for the detection of conversion electrons and gamma rays by a 4?? counter are very important to obtain accurate ...

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 ...

This paper reports on the Frascati Tokamak Upgrade (FTU) neutron activation system has been calibrated using indium foils and a {sup 252}Cf spontaneous fission neutron source located at several positions within the tokamak. The same experimental arrangements have been simulated with the MCNP Monte Carlo neutron and ...

For the purpose of the power calibration test of the Japanese Research Reactor No. 1, absolute measurements of thermal neutron flux in the core of the reactor were carried out using the method of neutron-induced activity of gold foils. The induced activities of Au/sup 198/ were measured ...

Gamma spectral analysis of irradiated material can be used to determine absolute disintegration rates for specific radionuclides. These data, together with measured values for the thermal and epithermal neutron fluxes, and irradiation, cooling and counting time values, are all the experimental information required to do absolute ...

... Accession Number : ADA074711. Title : Absolute Calibration of a Uranium - 238 Fast-Neutron Detector. Descriptive Note : Technical note,. ...

Most photoneutron sources used at present contain beryllium as the target material, more rarely deuterium. The photon sources are obtained by activation of suitable materials, such as antimony, in a reactor. For determination of the neutron yield the photoneutrons are compared with absolutely calibrated ...

The thermal neutron flux depression in a diffusing medium by an absorbing foil has been treated in numerous papers. The results are re-examined in an attempt to find a uniform and physically meaningful representation of the 'activation correction'. This quantity can be split up into a combination of probabilities. Thus, it is ...

Iodine has been determined in Norwegian cheese by combination of neutron activation and subsequent separation of radioiodine ( exp 128 I) by selective retention on Dowex 2-X8 anion exchange resin. Iodine may be detected down to 5ng in terms of absolute am...

Instrumental neutron activation analysis was used to determine the elemental concentrations in water and air solids samples collected on Nucleopore and Whatman filters from the Walker Branch Watershed. The results from this study show that the trace element concentrations removed by water from the watershed vary seasonally, as well as ...

A Ra- Be neutron source with a graphite moderator was used for the preparation of a reference standard for thermal neutron fluxes. The work involved the measurement of the spatial distribution of the slowing-down density on the basis of the activation of In foils along the principal axis of the graphite prism for determining ...

Three standard reference materials, flyash, soil, and ASI 4340 steel, were analyzed by a method of absolute instrumental neutron activation analysis (INAA). Two different light water pool-type reactors were used to produce equivalent analytical results even though the epithermal to thermal flux ratio in one reactor was higher than that ...

Absolute cross sections for pion-induced neutron knockout reactions and some more complex reactions on $sup 14$N, $sup 16$O, $sup 19$F and $sup 31$P were determined by activation at 190 MeV. Results are consistent with existing spallation models as modified by the recent final-state interaction theory of Sternheim and Silbar. ...

... Title : NEUTRON DOSIMETRY, SPECTROMETRY, AND NEUTRON ACTIVATION ANALYSIS. Descriptive Note : Final rept. ...

For the absolute measurement of the thermal neutron flux inside a nuclear reactor, a test specimen, e.g., a gold foil, is fluxed within a cartridge. The cartridge is movable inside a tube under the influence of pneumatic pressure, so that the cartridge is brought into position inside the reactor and held in this position by pressure against a stop ...

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 different types of ...

The most accurate absolutely calibrated measurement of the total yield of neutrons from experiments on the National Ignition Facility will be from activation of threshold nuclear reactions. The high-yield neutron activation system is being designed to provide high-accuracy (similar to the ...

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 ...

Prompt gamma-ray neutron activation analysis of 10B concentrations in biological samples was carried out using a germanium detector and single crystal silicon filtered neutron beams from the TRIGA-II reactor. The 10B concentrations of biological samples such as tumors, tissues, blood and cultured cells were estimated from calibration ...

A system has been established for determining the total body contents of calcium, phosphorus, sodium, chlorine and nitrogen by neutron activation analysis using sealed-tube neutron generators and a shadow-shield whole-body counter. The system was calibrated using three anthropomorphic phantoms of different sizes, filled with various ...

Determination of thermal to fast neutron flux ratio (f(fast)) and fast neutron flux (?(fast)) is required for fast neutron reactions, fast neutron activation analysis, and for correcting interference reactions. The f(fast) and subsequently ?(fast) were determined using the ...

The absolute sensitivity of a gamma-ray line following thermal or epithermal neutron activation is expressed as a product of four terms, namely, the intrinsic, irradiation, decay and measurement factors. The total absolute sensitivity is the sum of the absolute sensitivities due to thermal and ...

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 ...

Neutron yields were determined by measuring the activities produced in the INEL manganese bath. Of the three fission methods used, the neutron-fission coincidence method was found to be the most consistent and reliable. The value of /sup 252/Cf anti ..nu.. obtained by these measurements was 3.764. (RWR)

During the initial deuterium-tritium experiments on TFTR, neutron emission was measured with {sup 235}U and {sup 238}U fission chambers, silicon surface barrier diodes, spatially collimated {sup 4}He proportional counters and ZnS scintillators, and a variety of elemental activation foils. The activation foils, {sup 4}He counters and ...

... (Author). Descriptors : (*NEUTRON CROSS SECTIONS, *NEUTRON ACTIVATION), NEUTRON FLUX, NEUTRON SPECTRUM, FOILS(MATERIALS ...

A p-7Li quasi-monoenergetic neutron field for activation experiment has been developed at energies between 18 and 38 MeV. The absolute neutron intensity was accurately determined from the number of 7Be nuclei produced in the 7Li target which is equal to the number of the monoenergetic peak ...

Seven important body elements, C, N, Ca, P, K, Na, and Cl, can be measured with great precision and accuracy in the in vivo neutron activation facilities at Brookhaven National Laboratory. The facilities include the delayed-gamma neutron activation, the prompt-gamma neutron ...

Using Indium activation foils, the toroidal and poloidal neutron emission patterns were determined for PLT plasmas which include ICRF and neutral beam heating. The activities produced the /sup 115/In (n,n') /sup 115m/In reaction were determined by counting the 336 keV ..gamma.. line of the /sup 115m/In decay. This ...

... INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS FOR IODINE IN SEAWEEDS. ... FOR DETERMINING IODINE IN SEAWEED BY NEUTRON ...

In the present study a method used to normalize a collimated 14.7 MeV neutron beam is introduced. It combined a measurement of the fast neutron scalar flux passing through the collimator, using a copper foil activation, with a neutron transport calculation of the foil activation per unit source ...

The absolute neutron emission of a 100 mc Ra- alpha -Be and a 25 c Po- alpha -Be source was measured. The emitted neutron was moderated and absorbed in a manganese sulfate solution From a part of the solution the manganese was precipitated and after drying the activity was measured with calibrated gamma ...

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$ ...

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...

Absolutely calibrated measurements of the neutron yield are important for the evaluation of the plasma performance such as the fusion gain Q in DD operating tokamaks. Total neutron yield is measured with (sup 235)U and (sup 238)U fission chambers and (sup...

The International Thermonuclear Experimental Reactor will require highly accurate measurements of fusion power production in time, space, and energy. Spectrometers in the neutron camera could do it all, but experience has taught us that multiple methods with redundancy and complementary uncertainties are needed. Previously, conceptual designs have been presented for ...

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 ...

Accurate determinations of fusion neutron yields on the TFTR require that the neutron detectors be absolutely calibrated in-situ, using neutron sources of known strengths. For such calibrations, numerical simulations of neutron transport can be powerful t...

The gamma radiation of Sn/sup 116/ appearing as a result of the 54 min BETA transition of In/sup 116m/ was used for activation measurements. The free measurements of the gamma ratiation from eigen absorption in the foil permitted the effect of the neutron absorption in the foil to be detected, while in the measurement of the BETA ...

Cross sections for several nuclear reactions induced by 14-Mev neutrons were measured by the activation method. The number of activated atoms was determined by absolute beta-counting. Corrections for finite sample thicknesses were determined experimentally in every case. Cross sections for the following reactions ...

The last few years have witnessed considerable progress in the use of polarized neutron beam techniques for the study of condensed matter physics. Among the methods actively pursued at present are neutron spin echo as pioneered by Mezei for ultra high resolution and the energy integrated magnetic scattering measurement technique ...

This work aimed to determine the irradiator thermal (under-cadmium) and fast (over-cadmium) neutron fluxes, of the Nuclear Experimental Laboratory of the Nuclear Engineering Center (CNEN-IPEN, S�o Paulo, Brazil), and the possibility of this irradiator use for Neutron Activation Analysis (NAA), by the absolute ...

Fast neutron contamination in photon beams in the 20 MV range have been reported in recent years. In order to determine if the variations were due mainly to differences in measurement procedures, or inherent in the design of the accelerators, three different 18-MV (BJR) photon beams were compared using identical analytical techniques. The units studied were a Philips SL/75-20 ...

The performance of diagnostic systems are limited by their weakest constituents, including their calibration issues. Neutron diagnostics are notorious for problems encountered while determining their absolute calibrations, due mainly to the nature of the neutron transport problem. In order to facilitate the determination of an accurate ...

A procedure is described for the determination of sodium in natural silicate minerals by pile neutron activation and counting the induced gamma radiation in the irradiated specimen without chemical processing. An integral scintillation counter set to accept all gamma -rays with energies above 2.6 Mev is used for radioactivity measurement. ...

The determination of potassium in natural silicate minerals by pile neutron activation and by counting the induced beta radiation in the irradiated specimen without chemi cal processing is described. An end-window proportional counter and aluminum absorbers are used for radioactivity measurement. Precision and absolute ...

This report describes how cobalt wire may be used for the absolute integration of thermal neutron density over any period of time up to several years. Thermal neutron densities in B.E.P.O. have been measured by irradiating together cobalt wires and sodium carbonate. The absolute values of the thermal ...

Formulae permitting to determine the rates of parent nuclei production reactions in activation conditions in nonstationary flux, based on activation of daughter nuclei, are derived. An expression for decay correction while measuring the daughter nuclei ac...

... SUCH AS COPPER ACTIVATION FOR 14 MEV NEUTRONS, AND TRACK ... WAS CONCLUDED THAT FAST-NEUTRON RADIOGRAPHY WITH ...

... Descriptors : *COMPUTER PROGRAMS), *NEUTRON ACTIVATION), (*NEUTRON FLUX, (*NEUTRON SPECTRUM, DETERMINATION), (*FOILS ...

The flux density at the sample position of GLEEP is calculated from the activation produced in gold and in manganese-nickel foils. The 4 pi BETA - gamma coincidence technique is shown to be applicable to the absolute measurement of Mn/sup 56/ in foils in spite of the complexity of the decay scheme. The flux density is estimated at 1.663 x ...

An accurate knowledge of neutron-induced ?-ray production cross sections is important in enabling the determination of absolute cross sections from relative measurements of ?-ray yields. Such data have a variety of uses, for example, in determining reaction cross sections for activation of materials used as integral ...

The DT program at the Tokamak Fusion Test Reactor (TFTR) created requirements on 14 MeV neutron measurements to measure from 10{sup 6} n/cm{sup 2} (for triton burnup and Ohmic tritium plasmas) to {gt}10{sup 12} n/cm{sup 2} (characteristic of {gt}10 MW DT plasmas) with an accuracy of 7% (one-sigma).1 To maintain an absolute calibration over this dynamic ...

... Descriptors : *Neutron detectors, *Neutron activation, Calibration, Measurement, Neutron flux, Neutron spectrum, Dosage, Radioactive isotopes ...

There are three primary goals for the Neutron Activation system for ITER: maintain a robust relative measure of fusion power with stability and high dynamic range (7 orders of magnitude); allow an absolute calibration of fusion power (energy); and provide a flexible and reliable system for materials testing. The nature of the ...

The beta decay of the free neutron is the archetypical semileptonic weak nuclear reaction. According to the Standard Model it is a mixed vector/axial vector current process characterized by two coupling strengths: g{sub a} and g{sub v}, the axial and vector coupling coefficients. As a consequence of this, precise measurements of the absolute decay rate and ...

This paper aims to evaluate the performance of the source description of the THOR BNCT beam via different measurement techniques in different phantoms. The measurement included (1) the absolute reaction rate measurement of a set of triple activation foils, (2) the neutron and gamma-ray dose rates measured using the paired ionization ...

An apparatus for making absolute measurement of the thermal neutron flux in the core of the EL-3 reactor at Saclay by means of activation detectors is described. The apparatus consists of a pneumatic transfer system provided with solenoid valves whose sequence of operation is electronically controlled according to a ...