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Prompt gamma neutron activation analysis. Prompt gamma neutron activation analysis PGNAA is a technique for the analysis of elements present in solid, liquid and gaseous samples by measuring the capture gamma rays emitted from the sample during neutron irradiation.
The technique is complementary to conventional neutron activation analysis NAA as it can be used in number of cases where NAA fails. Though the technique was first used in sixties, the advantage of the technique was first highlighted by Lindstrom and Anderson.
PGNAA is increasingly being used as a rapid, instrumental, nondestructive and multielement analysis technique. A monograph and several excellent reviews on this topic have appeared recently. In this review, an attempt has been made to bring out the essential aspects of the technique, experimental arrangement and instrumentation involved, and areas of application.
Some of the results will also be presented. In this study, principle of prompt gamma neutron activation analysis has been used as a technique to determine the elements in the sample. Concrete with size of 10x10x10 cm 3 and 15x15x15 cm 3 were analysed as sample.
When neutrons enter and interact with elements in the concrete, the neutron capture reaction will occur and produce characteristic prompt gamma ray of the elements. The preliminary result of this study demonstrate the major element in the concrete was determined such as Si, Mg, Ca, Al, Fe and H as well as others element, such as Cl by analysis the gamma ray lines respectively.
The potential and the capability of neutron induced prompt gamma as tool for multi elemental analysis qualitatively to identify the elements present in the concrete sample discussed. Prompt gamma -ray activation analysis PGAA.
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Prompt Gamma Ray Spectroscopy for process monitoring. Prompt Gamma Ray Spectroscopy PGRS is a very powerful analytical technique able to measure many metallic, contamination problem elements. The technique involves measurement of gamma rays that are emitted by nuclei upon capturing a neutron.
This method is sensitive not only to the target element but also to the particular isotope of that element. Plsger is capable of measuring dissolved metal ions in a flowing system. Due to high penetrating plagee of gamma radiation, high efficiency gamma ray detectors can be placed in an appropriate geometry to maximize sensitivity, providing real-time monitoring with low detection level capabilities.
Gamma -Ray Burst Prompt Correlations. Directory sikvia Open Access Journals Sweden. Full Text Available The mechanism responsible for the prompt emission of gamma -ray bursts GRBs is still a debated issue. The prompt phase-related GRB correlations can allow discriminating among the most plausible theoretical models explaining this emission.
We present an overview of the observational two-parameter correlations, their physical interpretations, and their use as redshift estimators and possibly as cosmological tools.
However, GRBs spanning several orders of magnitude in their energetics are far from being standard candles.
We describe the advances in the prompt correlation research in the past decades, with particular focus paid to the discoveries in the last 20 years. Development of prompt gamma activation analysis. Application of prompt gamma -activation analysis to some environmental samples and NBS’s standard reference materials were examined, using NBS reactor and the technique developed by the nuclear chemistry group of the University of Maryland.
Neutron moderation effects were measured in bulk soil samples through prompt gamma ray measurements from water and benzene contaminated soil samples using 14 MeV neutron inelastic scattering. Since neutron moderation effects strongly depend upon hydrogen concentration of the sample, for comparison purposes, moderation effects were studied from samples containing different hydrogen concentrations.
The soil samples with different hydrogen concentration were prepared by mixing soil with water as well as benzene in different weight proportions. Then, the effects of increasing water and benzene concentrations on the yields of hydrogen, carbon and silicon prompt gamma rays were measured. Moderation effects are more pronounced in soil samples mixed with water as compared to those from soil samples mixed with benzene.
Results of the study will be presented. A link between prompt optical and prompt gamma -ray emission in gamma -ray bursts. The prompt optical emission that arrives with the gamma -rays from a cosmic gamma -ray burst GRB is a signature of the engine powering the burst, the properties of the ultra-relativistic ejecta of the explosion, and the ejecta’s interactions with the surroundings.
Until now, only GRB had been detected at optical wavelengths during the burst phase. Its prompt optical emission was variable and uncorrelated with the prompt gamma -ray emission, suggesting that the optical emission was generated by a reverse shock arising from the ejecta’s collision with surrounding material. Here we report prompt optical emission from GRB a. It is variable and correlated with the prompt gamma -rays, indicating a common origin for the optical light and the gamma -rays.
Within the context of the standard fireball model of GRBs, we attribute this new optical component to internal shocks driven into the burst ejecta by variations of the inner engine.
The correlated optical emission is a direct probe of the jet isolated from the medium.
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The timing of the uncorrelated optical emission is strongly dependent on the nature of the medium. New possibilities in prompt gamma ray spectrometry. Prompt gamma ray spectrometry has been used as an analytical tool for many years. The high level of background noise does, however, remain a major problem with this technique. From simple theoretical consideration, conditions particle, energy were determined to reduce significantly the background noise under irradiation.
Alpha particles of 3. Some fifty elements were studied, of which 24 gave interesting results. The detection limits obtained for a sample of niobium were as follows: Numerous applications may be envisaged in the geo- and cosmo-sciences.
Estimation of neutron energy distributions from prompt gamma emissions. A technique of estimating the incident neutron energy distribution from emitted prompt gamma intensities from a system exposed to neutrons is presented. The emitted prompt gamma intensities or the measured photo peaks in a gamma detector are related to the incident neutron energy distribution through a convolution of the response of the system generating the prompt gammas to mono-energetic neutrons.
The emitted five prompt gamma peaks from hydrogen, boron, carbon and lead can be utilized to unfold the incident neutron energy distribution as an under-determined deconvolution problem. Feasibility of the proposed technique is demonstrated theoretically using the Monte Carlo calculated response matrix and intensities of emitted prompt gammas from the Pb-covered BHDPE-HDPE system in the case of several incident neutron spectra spanning different energy ranges.
Bulk density calculations from prompt gamma ray yield. The gamma ray yield from a Prompt Gamma ray Neutron Activation Analysis PGNAA setup is a linear function of element concentration and neutron flux in a the sample with constant bulk density.
If the sample bulk density varies as well, then the element concentration and the neutron flux has a nonlinear correlation with the gamma ray yield . The measurement of gamma ray yield non-linearity from samples and a standard can be used to estimate the bulk density of the samples.
Due to different bulk densities of the blended cement samples, the measured gamma ray yields have nonlinear correlation with calcium and silicon concentration of the samples. The non-linearity in the yield was observed to increase with gamma rays energy and element concentration. The bulk densities of the cement samples were calculated from ratio of gamma ray yield from blended cement and that from a Portland cement standard.
The calculated bulk densities have good agreement with the published data. The result of this study will be presented. Application of prompt gamma -ray activation analysis.
This technical report is written for the promotion to utilization of prompt gamma -ray activation analysis facility to be installed in HANARO reactor.
It is described for a practical aspects including experiment and equipments, methodology, current status of the research and silcia and its dilvia. Proton current measurements using the prompt gamma ray diagnostic technique. In these measurements, the proton beam was allowed to strike cylindrical thick lithium metal targets. The positron activity of the copper sample was easily measured using coincidence counting techniques.
The number silviw 62 Cu atoms produced per proton incident on a thick Li metal target was determined with separate calibration runs performed on the Sandia 2.
The time history of the prompt gamma production was measured using six EGG NPM scintillator photomultiplier combinations shielded by The use of six scintillator photomultiplier combinations was necessary to increase the statistical precision of the data. The normalization of the prompt gamma time history data with the total time integrated proton-current measurement yielded the absolute time resolved proton current on target.
Data from runs performed on the Sandia Proto I accelerator will be presented. Prompt gamma -ray imaging for small animals. Small animal imaging is recognized as a powerful discovery tool for small animal modeling of human diseases, which is providing an important clue to complete understanding of disease mechanisms and is helping researchers develop and test new treatments. A new imaging modality called prompt gamma -ray imaging PGI has been identified and investigated primarily by Monte Carlo simulation.
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Currently it is suggested for use on small animals. This new technique could greatly enhance and extend the present capabilities of PET and SPECT imaging from ingested radioisotopes to the imaging of selected non-radioactive elements, such as Gd, Cd, Hg, and B, and has the great potential to be used in Neutron Cancer Therapy to monitor neutron distribution and neutron-capture agent distribution.
This approach consists of irradiating small animals in the thermal neutron beam of a nuclear reactor to produce prompt gamma rays from the elements in the sample by the radiative capture n, gamma reaction.
These prompt gamma rays are emitted in energies that are characteristic of each element and they are also produced in characteristic coincident chains. After measuring these prompt gamma rays by surrounding spectrometry array, the distribution of each element of interest in the sample is reconstructed from the mapping of each detected signature gamma ray by either electronic collimations or mechanical collimations. In addition, the transmitted neutrons from the beam can be simultaneously used for very sensitive anatomical imaging, which provides the registration for the elemental distributions obtained from PGI.
The recent observations by the Fermi satellite of GRB C are then reviewed, and their implications for such models are discussed, together with its interesting determination of a bulk Lorentz factor, and the highest lower limit on the quantum gravity energy scale so far. In the context of particle therapy, particle range verification is a major challenge for the quality assurance of the treatment.
One approach is the measurement of the prompt gamma rays resulting from the tissue irradiation. A Compton camera based on several planes of position sensitive gamma ray detectors, together with an imaging algorithm, is expected to reconstruct the prompt gamma ray emission density profile, which is correlated with the dose distribution. Their spectrum has similarities with the one expected from prompt gamma rays in the clinical case, and these are also bunched with the accelerator frequency.
The time correlation between the pulsed prompt photons and the measured signals was used for background discrimination, achieving a time resolution of 3 ns 2 ns FWHM for the CZT LSO detector. A time-walk correction was applied for the LSO detector and improved its resolution to 1 ns.
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In conclusion, the detectors are suitable for time-resolved background discrimination in pulsed clinical particle accelerators. Ongoing tasks are the test of the imaging algorithms and the quantitative comparison with simulations. Further experiments will be performed at proton accelerators. Prompt gamma -ray analysis of steel slag in concrete. Blast furnace slag BFS is added to Portland cement concrete to increase its durability, particularly its corrosion resistance.
Monitoring the concentration of BFS in concrete for quality control purposes is desired.