WorldWideScience

Sample records for applying gamma spectroscopy

  1. Modulation gamma resonance spectroscopy

    International Nuclear Information System (INIS)

    Possibility to control dynamic processes in a matter through gamma-resonance modulation by high-frequency external variable fields in excess of inverse lifetimes of the Moessbauer nuclei excited states, that is, within the megahertz frequency range lies in the heart of the modulation gamma-resonance spectroscopy. Through the use of the gamma-resonance process theoretical analysis methods and of the equation solution method for the density matrix with the secondary quantization of gamma-radiation field one attacks the problems dealing with the effect of both variable fields and relaxation on gamma-resonance. One has studied the gamma-radiation ultrasound modulation stages. One points out a peculiar role of the gamma-magnetic resonance effect in modulation gamma resonance spectroscopy formation. One forecasts development of the modulation gamma-resonance spectroscopy into the nonlinear gamma-resonance spectroscopy

  2. High resolution gamma-ray spectroscopy applied to bulk sample analysis

    International Nuclear Information System (INIS)

    A high resolution Ge(Li) gamma-ray spectrometer has been installed and made operational for use in routine bulk sample analysis by the Bendix Field Engineering Corporation (BFEC) geochemical analysis department. The Ge(Li) spectrometer provides bulk sample analyses for potassium, uranium, and thorium that are superior to those obtained by the BFEC sodium iodide spectrometer. The near term analysis scheme permits a direct assay for uranium that corrects for bulk sample self-absorption effects and is independent of the uranium/radium disequilibrium condition of the sample. A more complete analysis scheme has been developed that fully utilizes the gamma-ray data provided by the Ge(Li) spectrometer and that more properly accounts for the sample self-absorption effect. This new analysis scheme should be implemented on the BFEC Ge(Li) spectrometer at the earliest date

  3. Simultaneous beta and gamma spectroscopy

    Science.gov (United States)

    Farsoni, Abdollah T.; Hamby, David M.

    2010-03-23

    A phoswich radiation detector for simultaneous spectroscopy of beta rays and gamma rays includes three scintillators with different decay time characteristics. Two of the three scintillators are used for beta detection and the third scintillator is used for gamma detection. A pulse induced by an interaction of radiation with the detector is digitally analyzed to classify the type of event as beta, gamma, or unknown. A pulse is classified as a beta event if the pulse originated from just the first scintillator alone or from just the first and the second scintillator. A pulse from just the third scintillator is recorded as gamma event. Other pulses are rejected as unknown events.

  4. Gamma spectroscopy vials standardization

    International Nuclear Information System (INIS)

    Three types of plastic vials were defined by GTR 5 (Radioprotection Instrumentation Committee) according to the needs of laboratories of measuring by gamma spectrometry. A transparent (SG 50 T) or opaque (SG 50 N) vial of 50 cm3 for the range of activities more than 2,5.10-3 Bq/cm3. A transparent (SG 500 T) or opaque (SG 500 N) vial of 500 cm3 for low activities (at least 5.10-4 Bq/cm3), but with the possibility of using theses samples in existing automatic runs. A transparent (SG 3000 T) vial of 3000 cm3 allowing to obtain the minimum level of activity (at least 10-4 Bq/cm3), owing to the shape which envelopes the detector. The LMRI can supply straight standards in SG 50 N and SG 500 N vials. The moulds of these vials are the property of the CEA which insures the continuity of production

  5. Planetary gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    The chemical composition of a planet can be inferred from the gamma rays escaping from its surface and can be used to study its origin and evolution. The measured intensities of certain gamma rays of specific energies can be used to determine the abundances of a number of elements. The major sources of these gamma-ray lines are the decay of natural radionuclides, reactions induced by energetic galactic-cosmic-ray particles, capture of low energy neutrons, and solar-proton-induced radioactivities. The fluxes of the more intense gamma-ray lines emitted from 30 elements were calculated using current nuclear data and existing models. The source strengths for neutron-capture reactions were modified from those previously used. The fluxes emitted from a surface of average lunar composition are reported for 288 gamma-ray lines. These theoretical fluxes have been used elsewhere to convert the data from the Apollo gamma-ray spectrometers to elemental abundances and can be used with results from future missions to map the concentrations of a number of elements over a planet's surface. Detection sensitivities for these elements are examined and applications of gamma-ray spectroscopy for future orbiters to Mars and other solar-system objects are discussed

  6. Planetary gamma-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Reedy, R.C.

    1978-01-01

    The chemical composition of a planet can be inferred from the gamma rays escaping from its surface and can be used to study its origin and evolution. The measured intensities of certain gamma rays of specific energies can be used to determine the abundances of a number of elements. The major sources of these gamma-ray lines are the decay of natural radionuclides, reactions induced by energetic galactic-cosmic-ray particles, capture of low energy neutrons, and solar-proton-induced radioactivities. The fluxes of the more intense gamma-ray lines emitted from 30 elements were calculated using current nuclear data and existing models. The source strengths for neutron-capture reactions were modified from those previously used. The fluxes emitted from a surface of average lunar composition are reported for 288 gamma-ray lines. These theoretical fluxes have been used elsewhere to convert the data from the Apollo gamma-ray spectrometers to elemental abundances and can be used with results from future missions to map the concentrations of a number of elements over a planet's surface. Detection sensitivities for these elements are examined and applications of gamma-ray spectroscopy for future orbiters to Mars and other solar-system objects are discussed.

  7. Gamma spectroscopy in hypernuclei

    International Nuclear Information System (INIS)

    We have started a project of high-resolution hypernuclear γ-spectroscopy using a recently-constructed germanium detector system (Hyperball). In the first experiment (KEK E419), we observed two γ transitions in Λ7Li, the spin-flip M1(3/2+ → 1/2+) at 691.7 ± 0.65stat ± 1.0sys keV and the E2(5/2+ → 1/2+) at 2050.4 ± 0.4stat ± 0.7sys keV. The former gives unambiguous information on the strength of the ΛN spin-spin interaction. B(E2) of the latter transition was measured to be 3.6 ± 0.5stat-0.4+0.5sys e2fm4. In the second experiment (BNL E930), we observed the E2(5/2+, 3/2+ → 1/2+) transitions of Λ9Be at around 3.05 MeV, which suggests a small ΛN spin-orbit interaction. Such studies for various p-shell Λ hypernuclei are being continued to determine all the ΛN spin-dependent interactions. Intense beams at JHF 50 GeV PS allow us γ-spectroscopy of heavier hypernuclei, neutron rich hypernuclei, and double Λ hypernuclei, etc. (author)

  8. Mathematical efficiency calibration in gamma spectroscopy

    CERN Document Server

    Kaminski, S; Wilhelm, C

    2003-01-01

    Mathematical efficiency calibration with the LabSOCS software was introduced for two detectors in the measurement laboratory of the Central Safety Department of Forschungszentrum Karlsruhe. In the present contribution, conventional efficiency calibration of gamma spectroscopy systems and mathematical efficiency calibration with LabSOCS are compared with respect to their performance, uncertainties, expenses, and results. It is reported about the experience gained, and the advantages and disadvantages of both methods of efficiency calibration are listed. The results allow the conclusion to be drawn that mathematical efficiency calibration is a real alternative to conventional efficiency calibration of gamma spectroscopy systems as obtained by measurements of mixed gamma ray standard sources.

  9. Simultaneous beta/gamma digital spectroscopy

    Science.gov (United States)

    Farsoni, Abdollah T.

    A state-of-the-art radiation detection system for simultaneous spectroscopy of beta-particles and gamma-rays has been developed. The system utilizes a triple-layer phoswich detector and a customized Digital Pulse Processor (DPP) built in our laboratory. The DPP board was designed to digitally capture the analog signal pulses and, following several digital preprocessing steps, transfer valid pulses to the host computer for further digital processing. A MATLAB algorithm was developed to digitally discriminate beta and gamma events and reconstruct separate beta and gamma-ray energy spectra with minimum crosstalk. The spectrometer proved to be an effective tool for recording separate beta and gamma-ray spectra from mixed radiation fields. The system as a beta-gamma spectrometer will have broad-ranging applications in nuclear non-proliferation, radioactive waste management, worker safety, systems reliability, dose assessment, and risk analysis.

  10. Nuclear forensics using gamma-ray spectroscopy

    CERN Document Server

    Norman, Eric B

    2016-01-01

    Much of George Dracoulis's research career was devoted to utilizing gamma-ray spectroscopy in fundamental studies in nuclear physics. This same technology is useful in a wide range of applications in the area of nuclear forensics. Over the past several years, our research group has made use of both high- and low- resolution gamma ray spectrometers to: identify the first sample of plutonium large enough to be weighed; determine the yield of the Trinity nuclear explosion; measure fission fragment yields as a function of target nucleus and neutron energy; and observe fallout in the U. S. from the Fukushima nuclear reactor accident.

  11. Very high count rate gamma spectroscopy

    International Nuclear Information System (INIS)

    Recent improvements in the electronics that amplify and analyze gamma photon-induced pulses have made it possible for HPGe coaxial detectors to accept input rates of one-million, one-MeV gamma photons-per-second and still provide the spectroscopist with spectra that can be analyzed. Data are presented that illustrate peak area variances and changes in counting uncertainty statistics due to the greatly extended count rate range. Software algorithms are presented that allow gain shift and peak resolution to be adjusted automatically on a sample-by-sample basis. Relationships are developed between integrated count rate and the variances of full energy photon peak area and counting uncertainty when using the real time correction mode of pulse processing. Finally, the results of integrating hardware and software into a system are used to illustrate that quantitative gamma spectroscopy over counting rates of one- to one-million counts-per-second are achievable

  12. Gamma spectroscopy in water cooled reactors

    International Nuclear Information System (INIS)

    Gamma spectroscopy analysis of spent fuels in power reactors; study of two typical cases: determination of the power distribution by the mean of the activity of a low periodic element (Lanthanum 140) and determination of the burnup absolute rate by examining the ratio of Cesium 134 and Cesium 137 activities. Measures were realized on fuel solutions and on fuel assemblies. Development of a power distribution map of the assemblies and comparison with the results of a three dimensional calculation of core evolution

  13. Handbook of Applied Solid State Spectroscopy

    CERN Document Server

    Vij, D. R

    2006-01-01

    Solid-State spectroscopy is a burgeoning field with applications in many branches of science, including physics, chemistry, biosciences, surface science, and materials science. Handbook of Applied Solid-State Spectroscopy brings together in one volume information about various spectroscopic techniques that is currently scattered in the literature of these disciplines. This concise yet comprehensive volume covers theory and applications of a broad range of spectroscopies, including NMR, NQR, EPR/ESR, ENDOR, scanning tunneling, acoustic resonance, FTIR, auger electron emission, x-ray photoelectron emission, luminescence, and optical polarization, and more. Emphasis is placed on fundamentals and current methods and procedures, together with the latest applications and developments in the field.

  14. Correlation spectroscopy applied to glycerol polyester spectra

    Science.gov (United States)

    The recent development of glycerol polyesters for use as controlled release matrix materials in the nutraceuticals and pharmaceuticals industries presented a unique opportunity to apply correlation spectroscopy. In a typical formulation the glycerol is reacted with a polyfunctional acid such as citr...

  15. Quantitative gamma spectroscopy at very high counting rates

    International Nuclear Information System (INIS)

    Loss-free net peak areas at variable input rates of more than 690,000 c/s have been obtained by means of a high-rate gamma spectroscopy system with real-time compensation of counting losses, thus providing evidence for the feasibility of quantitative gamma spectroscopy at counting rates not attained until now. (orig.)

  16. Gamma-ray spectroscopy on irradiated fuel rods

    International Nuclear Information System (INIS)

    The recording of gamma-ray spectra along an irradiated fuel rod allows the fission products to be qualitatively and quantitatively examined. Among all nondestructive examinations performed on irradiated fuel rods by gamma-ray spectroscopy, the most comprehensive one is the average burnup measurement, which is quantitative. Moreover, burnup measurements by means of gamma-ray spectroscopy are less time-consuming and waste-generating than burnup measurements by radiochemical, destructive methods. This work presents the theoretical foundations and experimental techniques necessary to measure, using nondestructive gamma-ray spectroscopy, the average burnup of irradiated fuel rods in a laboratory equipped with hot cells. (author)

  17. Albedo method applied to coupled neutron-gamma shielding radiations

    International Nuclear Information System (INIS)

    The Albedo Theory was applied in order to develop an one-group algorithm for coupled neutron-gamma shielding calculations. The configuration analyzed consists of multilayered plane systems, where a incident neutron current generates gamma radiation through neutron-gamma reactions. The results obtained by Albedo Method and ANISN code have shown excellent agreement. (author)

  18. Applied spectroscopy and the science of nanomaterials

    CERN Document Server

    2015-01-01

    This book focuses on several areas of intense topical interest related to applied spectroscopy and the science of nanomaterials. The eleven chapters in the book cover the following areas of interest relating to applied spectroscopy and nanoscience: ·         Raman spectroscopic characterization, modeling and simulation studies of carbon nanotubes, ·         Characterization of plasma discharges using laser optogalvanic spectroscopy, ·         Fluorescence anisotropy in understanding protein conformational disorder and aggregation, ·         Nuclear magnetic resonance spectroscopy in nanomedicine, ·         Calculation of Van der Waals interactions at the nanoscale, ·         Theory and simulation associated with adsorption of gases in nanomaterials, ·         Atom-precise metal nanoclusters, ·         Plasmonic properties of metallic nanostructures, two-dimensional materials, and their composites, ·         Applications of graphe...

  19. Fluorescence spectroscopy applied to orange trees

    Science.gov (United States)

    Marcassa, L. G.; Gasparoto, M. C. G.; Belasque, J., Jr.; Lins, E. C.; Dias Nunes, F.; Bagnato, V. S.

    2006-05-01

    In this work, we have applied laser-induced fluorescence spectroscopy to investigate biological processes in orange trees (Citrus aurantium L.). We have chosen to investigate water stress and Citrus Canker, which is a disease caused by the Xanthomonas axonopodis pv. citri bacteria. The fluorescence spectroscopy was investigated by using as an excitation source a 442-nm 15-mW HeCd gas multimode discharge laser and a 532-nm 10-mW Nd3+:YAG laser. The stress manifestation was detected by the variation of fluorescence ratios of the leaves at different wavelengths. The fluorescence ratios present a significant variation, showing the possibility to observe water stress by fluorescence spectrum. The Citrus Canker’s contaminated leaves were discriminated from the healthy leaves using a more complex analysis of the fluorescence spectra. However, we were unable to discriminate it from another disease, and new fluorescence experiments are planned for the future.

  20. Terahertz spectroscopy applied to food model systems

    DEFF Research Database (Denmark)

    Møller, Uffe

    Water plays a crucial role in the quality of food. Apart from the natural water content of a food product, the state of that water is very important. Water can be found integrated into the biological material or it can be added during production of the product. Currently it is difficult to differ...... differentiate between these types of water in subsequent quality controls. This thesis describes terahertz time-domain spectroscopy applied on aqueous food model systems, with particular focus on ethanol-water mixtures and confined water pools in inverse micelles....

  1. Gamma-ray spectroscopy with relativistic exotic heavy-ions

    Indian Academy of Sciences (India)

    Samit Mandal; J Gerl; H Geissel; K Hauschild; M Hellström; Z Janas; I Kojouharov; Y Kopatch; R C Lemmon; P Mayet; Z Podolyak; P H Regan; H Schaffner; C Schlegel; J Simpson; H J Wollersheim

    2001-07-01

    Feasibility of gamma-ray spectroscopy at relativistic energies with exotic heavy-ions and new generation of germanium detectors (segmented Clover) is discussed. An experiment with such detector array and radioactive is discussed.

  2. Coincidence summing in gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    A new technique has been developed to calculate coincidence-summing corrections in γ-ray spectroscopy. In this technique the general coincidence-summing equations were derived in matrix notation, which allowed extracting either the first-order correction (combinations of only two coincident γ-rays) or a full correction (all possible combinations of emitted γ-rays). Subsequently, it is shown how the technique can be applied to the determination of the source disintegration rate, γ-ray emission rates or peak efficiencies in the presence of coincidence summing. In particular, the technique has been applied to the determination of peak efficiencies of a germanium detector. The peak efficiencies were iterated self-consistently using the coincidence-summing equations. The above calculation showed that, in general, the full correction is necessary for complicated decay schemes. In addition, a method has been developed to determine the peak-to-total ratio for a germanium detector in the presence of an interfering γ-ray. (orig.)

  3. Gamma radiography applied to aircraft maintenance

    International Nuclear Information System (INIS)

    Gamma-radiography as used in aircraft maintenance was introduced in the 1960's and is almost entirely focussed on the jet engine. It is used to identify cracking, corrosion, distortion, distress, assembly, alignment and wear. The general arrangement of an axial flow engine will permit the placement of a radiographic source in the central shaft. The radiations emitted may be directed at an appropriate angle to the part examined to produce a radiographic image. The techniques presented here are used to monitor the condition of specific rotating and non-rotating components in the gas flow path of high by-pass jet engines. Conventional gamma radiography equipment is used. The source is almost always Iridium-192, of between 800-3000 GBq. It has effective energies of 400-600 kV and a half-life of about 75 days. Exposure control and positioning apparatus is the same as for other industrial radiography with rigid guide tubes to locate the source centrally within the engine. The use of this inspection technique is realised as lower maintenance expenses than would otherwise be possible for the equivalent level of reliability. 19 refs., 12 figs

  4. A system for simultaneous beta and gamma spectroscopy

    Science.gov (United States)

    Farsoni, A. T.; Hamby, D. M.

    2007-08-01

    A state-of-the-art radiation detection system for real-time and simultaneous spectroscopy of beta-particles and gamma-rays has been developed. The system utilizes a triple-layer phoswich detector and a customized Digital Pulse Processor (DPP) designed and built in our laboratory. The DPP board digitally captures the analog signal pulses and, following several digital preprocessing steps, transfers valid pulses to the host computer for further digital processing. A resolving algorithm also was developed to digitally discriminate beta and gamma events, and reconstruct separate beta and gamma-ray energy spectra with minimal crosstalk. The spectrometer has proven to be an effective tool for recording separate beta and gamma-ray spectra from mixed radiation fields. The system as a beta-gamma spectrometer will have broad-ranging applications in nuclear non-proliferation, radioactive waste management, worker safety, systems reliability, dose assessment, and risk analysis.

  5. Multigroup albedo method applied to gamma radiation shielding

    International Nuclear Information System (INIS)

    The Albedo method, when applied to shielding calculations, is characterized by following the radiation through the materials, determining the reflected, absorbed and transmitted fractions of the incident current, independently of flux calculations. The excellent results obtained to neutron shielding cases in which the diffusion approximation could be applied motivated this work, where the method was applied in order to develop a multigroup and multilayered algorithm. A gamma radiation shielding simulation was carried out to a system constituted by three infinite slabs of varied materials and six energy groups. The results obtained by Albedo Method were the same generated by ANISN, a consecrated deterministic nuclear code. Concludingly, this work demonstrates the validity of Albedo Method to gamma radiation shielding analysis through its agreement with the full Transport Equation. (author)

  6. Analytical applications of neutron capture gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    Prompt gamma-rays from thermal induced nuclear reactions have been used to estimate the boron, chlorine and phosphorus contents in industrial and reference materials. A neutron capture gamma-ray spectroscopy facility for analytical purposes using 252-Cf sources has been designed and calibrated. The facility is principally designed for the measurement of the prompt gamma-ray spectra obtained due to thermal neutron capture by means of the internal target geometry. The capture spectra were recorded using a high resolution Ge(Li) system. The designed facility and the system used in this work are described in detail. A weight of 50 to 100 gm of each sample in a power or liquid form encapsulated in a polyethene container was used. Sensitivity curves using different standard concentration values of B, Cl and P, were constructed. The concentration range was from 0.005 to 30%. (orig.)

  7. Gamma spectroscopy: from steady beams to radioactive beams

    International Nuclear Information System (INIS)

    The author gives an overview of his research works in the field of gamma spectroscopy. First, he recalls some results of experiments performed for the study of peculiar structures associated with different modes of nucleus rotation, and notably in the case of collective rotation of deformed and even super-deformed nuclei. Then, he details tools and methods used to experimentally determine the level scheme. The main characteristics of steady and radioactive beams are briefly presented, and their complementarities and differences are highlighted. Specific spectrometers and sensors are described. In a last chapter, the author discusses several research projects he is involved in, and more particularly the 'gamma tracking' which is the fundamental principle for gamma multi-sensors of the next generations

  8. A BGO scintillating bolometer for gamma and alpha spectroscopy

    OpenAIRE

    Cardani, Laura; Di Domizio, Sergio; Gironi, Luca

    2012-01-01

    A 891 g BGO scintillating bolometer has been tested at 10 mK in the underground Laboratori Nazionali del Gran Sasso (Italy). The discrimination capability, the radio-purity of the compound and the main features of the crystal have been studied in order to demonstrate the excellent performances obtained by operating a scintillating bolometer in the field of gamma and alpha spectroscopy. The sensitivity of this detector in the study of extremely low surface contaminations has been investigated.

  9. ESR spectroscopy dating of recently excavated archaeological bone samples from Kottapuram site using gamma irradiation

    International Nuclear Information System (INIS)

    The study of radiation defects created in biomaterials such as bones can be used in dating with importance to paleontology and archaeology. Electron Spin Resonance Spectroscopy is applied to estimate the age of bones excavated from the archaeological site at Kottapuram in Kerala state south India. Gamma irradiated samples were analyzed by ESR spectrometry in order to obtain the growth curve and showed ESR behavior. The age of the bone samples were determined. (author)

  10. {gamma}-ray spectroscopy of N = Z nuclei.

    Energy Technology Data Exchange (ETDEWEB)

    Lister, C. J.

    1999-09-10

    The use of {gamma}-ray spectroscopy to probe the properties of marginally bound nuclear states has evolved from being a curiosity a decade ago to being the mainstream use for these devices. The key to this success has been the development of ultra-sensitive channel selection techniques which allow the parentage of each emitted y-ray to be established. With these techniques, and the enhanced efficiency of the arrays themselves, the level of sensitivity for nuclear spectroscopy has increased by several orders of magnitude, in some special cases reaching the 10's nanobarns level, 1000 times more sensitive than was possible a decade ago. In this paper the author discusses some recent developments in light nuclear spectroscopy, on nuclei with N = Z, below mass 100. These examples have been chosen to compliment other presentations at this conference which have covered similar experiments in heavier nuclei.

  11. Developing a gamma spectroscopy system at the Savannah River Site

    International Nuclear Information System (INIS)

    This article presents details of a program begun at the Savannah River Site in 1990 to develop and improve the EMS gamma Spectroscopy system and develop it into a univerom, integrated and easily upgradable platform of Ethernet-based hardware and software. The program included implementing seven automated sample changers, numberous stand-alone detectors, and user friendly software designed to provide automated batch operation of data acquisition, review, and management while supporting the average of more than 10,000 samples annually to monitor radioactive waste effluents and contamination

  12. Gamma spectroscopy and optoelectronic imaging with hybrid photon detector

    CERN Document Server

    D'Ambrosio, C; Piedigrossi, D; Rosso, E; Cenceelli, V; De Notaristefani, F; Masini, Gérald; Puertolas, D; Cindolo, F; Mares, J A; Nikl, M; Abreu, M; Rato-Mendes, P; Sousa, P

    2003-01-01

    Hybrid Photon Detectors (HPD) detect light via photocathodes and accelerate the emitted photoelectrons by an electric field towards silicon PIN-anodes, where they are absorbed and generate electronic signals. We have developed two specific types of HPDs: (1) Hybrid photomultiplier tubes for photon counting and gamma spectroscopy; (2) Imaging silicon pixel array tubes for optoelectronic cameras. This paper will illustrate the main achievements, which we obtained in the last years, and will describe and discuss our present main R&D efforts, in particular, in the biomedical imaging field. (27 refs).

  13. Elastic properties of gamma-Pu by resonant ultrasound spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Migliori, Albert [Los Alamos National Laboratory; Betts, J [Los Alamos National Laboratory; Trugman, A [Los Alamos National Laboratory; Mielke, C H [Los Alamos National Laboratory; Mitchell, J N [Los Alamos National Laboratory; Ramos, M [Los Alamos National Laboratory; Stroe, I [WORXESTER, MA

    2009-01-01

    Despite intense experimental and theoretical work on Pu, there is still little understanding of the strange properties of this metal. We used resonant ultrasound spectroscopy method to investigate the elastic properties of pure polycrystalline Pu at high temperatures. Shear and longitudinal elastic moduli of the {gamma}-phase of Pu were determined simultaneously and the bulk modulus was computed from them. A smooth linear and large decrease of all elastic moduli with increasing temperature was observed. We calculated the Poisson ratio and found that it increases from 0.242 at 519K to 0.252 at 571K.

  14. A phoswich detector for simultaneous alpha–gamma spectroscopy

    International Nuclear Information System (INIS)

    Phoswich detectors are of value for radiation spectroscopy, especially in cases where a low-cost solution for a mixed radiation field is desired. Meanwhile, simultaneous spectroscopy of alpha particles and gamma-rays has many applications in quantification and distinguishing the alpha-emitting radionuclides which usually occur in the analysis of environmental solid samples. Here, we have developed a system for detection of radioactive actinides (e.g., 241Am) based on the alpha–gamma coincidence technique. The underlying concept, is to assemble two appropriately selected scintillators (i.e., a fast and a slow one) together with a discriminating unit for analysis of their data. Detailed Monte Carlo simulation procedure has been developed using the GEANT4 toolkit to design and find enough knowledge about the response of the system in the studied radiation field. Various comparisons were made between experimental and simulation data which showed appropriate agreement between them. The calibration was performed and the MDA was estimated as 60 mBq for the phoswich system

  15. A phoswich detector for simultaneous alpha–gamma spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Moghadam, S. Rajabi [Department of Radiation Application, Shahid Beheshti University G.C., Tehran (Iran, Islamic Republic of); Feghhi, S.A.H., E-mail: A_feghhi@sbu.ac.ir [Department of Radiation Application, Shahid Beheshti University G.C., Tehran (Iran, Islamic Republic of); Safari, M.J. [Amirkabir University of Technology, Department of Energy Engineering and Physics, Tehran (Iran, Islamic Republic of)

    2015-11-01

    Phoswich detectors are of value for radiation spectroscopy, especially in cases where a low-cost solution for a mixed radiation field is desired. Meanwhile, simultaneous spectroscopy of alpha particles and gamma-rays has many applications in quantification and distinguishing the alpha-emitting radionuclides which usually occur in the analysis of environmental solid samples. Here, we have developed a system for detection of radioactive actinides (e.g., {sup 241}Am) based on the alpha–gamma coincidence technique. The underlying concept, is to assemble two appropriately selected scintillators (i.e., a fast and a slow one) together with a discriminating unit for analysis of their data. Detailed Monte Carlo simulation procedure has been developed using the GEANT4 toolkit to design and find enough knowledge about the response of the system in the studied radiation field. Various comparisons were made between experimental and simulation data which showed appropriate agreement between them. The calibration was performed and the MDA was estimated as 60 mBq for the phoswich system.

  16. Large volume imaging arrays for gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    Cadmium zinc telluride (CZT, Cd1-xZnxTe) has proven to be an important material for the fabrication of room temperature nuclear detectors and spectrometers. The authors report for the first time on the characteristics of large volume (4 cm x 4 cm x 0.5 cm) cadmium zinc telluride gamma-ray imaging arrays produced by IMARAD Imaging Systems. These arrays are shown to possess high uniformity of response to gamma-photons in the energy range of about 50 to over 600 keV. High resolution photopeaks have been obtained without any pulse processing or compensation techniques. Excellent peak-to-valley ratios, goos efficiencies, and acceptable leakage currents have been measured. In addition measurements of the internal electric field indicate that the field is uniform and does not appear to be confined to only one region of the detector volume. Low temperature photoluminescence spectroscopy shows that the dominant peaks are different than those typically observed in high quality HPB material of the same composition obtained from other vendors. The authors believe that this material and the arrays that may be produced from it represent a significant step forward in the technology of room temperature semiconductor gamma and x-ray spectrometers

  17. Determination of planetary surfaces elemental composition by gamma and neutron spectroscopy

    International Nuclear Information System (INIS)

    Measuring the neutron and gamma ray fluxes produced by the interaction of galactic cosmic rays with planetary surfaces allow constraining the chemical composition of the upper tens of centimeters of material. Two different angles are proposed to study neutron and gamma spectroscopy: data processing and data interpretation. The present work is in line with two experiments, the Mars Odyssey Neutron Spectrometer (MONS) and the Selene Gamma Ray Spectrometer. A review of the processing operations applied to the MONS dataset is proposed. The resulting dataset is used to determine the depth of the hydrogen deposits below the Martian surface. In water depleted regions, neutron data allow constraining the concentration in elements likely to interact with neutrons. The confrontation of these results to those issued from the Gamma Ray Spectrometer onboard Mars Odyssey provides interesting insight on the geologic context of the Central Elysium Planitia region. These martian questions are followed by the study of the Selene gamma ray data. Although only preliminary processing has been done to date, qualitative lunar maps of major elements (Fe, Ca, Si, Ti, Mg, K, Th, U) have already been realized. (author)

  18. Neutron Capture Gamma-Ray Spectroscopy. Proceedings of the International Symposium on Neutron Capture Gamma-Ray Spectroscopy

    International Nuclear Information System (INIS)

    Experimental capabilities in the field of neutron capture gamma-ray spectroscopy have expanded greatly in the last few years; this has been due in large part to the advent of high-quality Ge(Li) detectors, improvements in electronic data processing, and improvements in bent-crystal spectrometers. Previously unsuspected phenomena, such as the '5. 5-MeV1 anomaly, have appeared and new research tools, such as neutron guide tubes, have been brought into use. Equally exciting developments have occurred in the theory of neutron capture. Complex spectra have yielded to analysis after account had been taken of such effects as vibration, rotation and Coriolis forces, and the theoretical prediction of capture spectra seems to be a future possibility. In view of the International Atomic Energy Agency's close interest in this subject and the need for an international exchange of ideas to analyse and study the latest developments, the organizers of the Symposium felt that work on neutron capture gamma-ray spectroscopy had achieved such valuable and significant results that the time had come for this information to be presented, examined and discussed internationally

  19. Accelerated ion beams for in-beam e-gamma spectroscopy

    NARCIS (Netherlands)

    Dionisio, JS; Vieu, C; Schuck, C; Meunier, R; Ledu, D; Lafoux, A; Lagrange, JM; Pautrat, M; Waast, B; Phillips, WR; Varley, BJ; Durell, JL; Dagnall, PG; Dorning, SJ; Jones, MA; Smith, AG; Bacelar, JCS; Rzaca-Urban, T; Folger, H; Vanhorenbeeck, J; Urban, W

    1998-01-01

    A few accelerated ion beam requirements for in-beam e-gamma spectroscopy are briefly reviewed as well as several features of the MP Tandem accelerator of IPN-Orsay and the accelerated ion-beam transport devices leading to the experimental area of in-beam e-gamma spectroscopy. In particular, the main

  20. Detection of contaminants along boreholes with prompt gamma spectroscopy

    International Nuclear Information System (INIS)

    Geophysical borehole logging techniques are used for estimating subsurface physical, chemical, geologic, and hydrologic parameters. Nuclear borehole logging techniques have advantages and disadvantages that tend to be complementary to those of physical sampling, and these in situ measurements can help address the drawbacks of physical sampling, including high costs, lengthy delays in obtaining results of analyses from laboratories, undersampling, sample-handling problems, and ambiguity in long-term monitoring. As part of an effort to reduce environmental restoration costs, we are evaluating in situ neutron-induced gamma-ray spectroscopy (multispectral) measurements in boreholes to map environmental contaminants. It has been known for some time that this technology is capable of identifying many elements, but earlier borehole equipment was not very sensitive

  1. Detection of contaminants along boreholes with prompt gamma spectroscopy

    International Nuclear Information System (INIS)

    Geophysical borehole logging techniques are used for estimating subsurface physical, chemical, geological, and hydrological parameters. Nuclear borehole logging techniques have advantages and disadvantages that tend to be complementary to those of physical sampling and these in situ measurements can help address the drawbacks of physical sampling, including high costs, lengthy delays in obtaining results of analyses from laboratories/under sampling, sample handling problems, and ambiguity in long-term monitoring. As part of an effort to reduce environmental restoration costs, we are evaluating in-situ neutron-induced gamma-ray spectroscopy (multispectral) measurements in boreholes to map environmental contaminants. It has been known for some time that this technology is capable of identifying many elements, but earlier borehole equipment was not very sensitive

  2. Measurement of plutonium isotopic composition by gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    The technology of the analysis of plutonium isotopic ratio is independent of the measurement geometry and applicable to samples of physical and chemical composition. Three standard plutonium samples were measured in the HPGe system. The results showed that CRM 136 and CRM 137 containing 238Pu(0.223%) and 238Pu(0.268%) were 18.4% and 14.2% error and CRM 138 of 238Pu(0.01%) was 76% error. However the analysis represented less than 1.6% and 9% error in the three standard samples of highly involved 239Pu and 240Pu. Therefore, gamma-ray spectroscopy is very effective in the plutonium isotope analysis, having greater than 10% in content

  3. Plutonium isotopic composition by gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    We discuss the general approach, computerized data analysis methods, and results of measurements to determine the isotopic composition of plutonium by gamma-ray spectroscopy. The simple techniques are designed to be applicable to samples of arbitrary size, geometry, chemical and isotopic composition that have attained 241Pu-237U equilibrium. The combination of the gamma spectroscopic measurement of isotopic composition coupled with calorimetric measurement of total sample power is shown to give a totally nondestructive determination of sample Pu mass with a precision of 0.6% for 1000-g samples of PuO2 with 12% 240Pu content. The precision of isotopic measurements depends upon many factors including sample size, sample geometry, and isotopic content. Typical ranges are found to be 238Pu, 239Pu, 0.1 to 0.5%; 240Pu, 2 to 5%; 241Pu, 0.3 to 0.7%; 242Pu (determined by isotopic correlation); and 241Am, 0.2 to 10%

  4. NMR spectroscopy applied to the eye: Drugs and metabolic studies

    Energy Technology Data Exchange (ETDEWEB)

    Saether, Oddbjoern

    2005-07-01

    NMR spectroscopy has been extensively applied in biomedical research during the last decades. It has proved to be an analytical tool of great value. From being mainly used in chemistry, technological developments have expanded the application of NMR spectroscopy to a great wealth of disciplines. With this method, biochemical information can be obtained by analysing tissue extracts. Moreover, NMR spectroscopy is increasingly employed for pharmacokinetic studies and analysis of biofluids. Technological progress has provided increased sensitivity and resolution in the spectra, which enable even more of the complexity of biological samples to be elucidated. With the implementation of high-resolution magic angle spinning (HR-MAS) NMR spectroscopy in biomedicine, intact tissue samples or biopsies can be investigated. Thus, NMR spectroscopy has an ever-increasing impact in metabolic screening of human samples and in animal models, and methods are also increasingly realised in vivo. The present work, NMR spectroscopy applied to eye research, consists of two main parts. Firstly, the feasibility to monitor fluorinated ophthalmic drugs directly in the eye was assessed. Secondly, HR-MAS H1 NMR spectroscopy was applied for metabolic profiling of the anterior eye segment, specifically to analyse metabolic changes in intact corneal and lenticular samples after cataractogenic insults. This work included metabonomics with the application of pattern recognition methods to analyse HR-MAS spectra of eye tissues. Optimisation strategies were explored for F19 NMR detection of fluorinated drugs in a phantom eye. S/N gains in F19 NMR spectroscopy were achieved by implementing time-share H1 decoupling at 2.35 T. The method is advantageous for compounds displaying broad spectral coupling patterns, though detection of drugs at concentrations encountered in the anterior eye segment after topical application was not feasible. Higher magnetic fields and technological improvements could enable

  5. NMR spectroscopy applied to the eye: Drugs and metabolic studies

    International Nuclear Information System (INIS)

    NMR spectroscopy has been extensively applied in biomedical research during the last decades. It has proved to be an analytical tool of great value. From being mainly used in chemistry, technological developments have expanded the application of NMR spectroscopy to a great wealth of disciplines. With this method, biochemical information can be obtained by analysing tissue extracts. Moreover, NMR spectroscopy is increasingly employed for pharmacokinetic studies and analysis of biofluids. Technological progress has provided increased sensitivity and resolution in the spectra, which enable even more of the complexity of biological samples to be elucidated. With the implementation of high-resolution magic angle spinning (HR-MAS) NMR spectroscopy in biomedicine, intact tissue samples or biopsies can be investigated. Thus, NMR spectroscopy has an ever-increasing impact in metabolic screening of human samples and in animal models, and methods are also increasingly realised in vivo. The present work, NMR spectroscopy applied to eye research, consists of two main parts. Firstly, the feasibility to monitor fluorinated ophthalmic drugs directly in the eye was assessed. Secondly, HR-MAS H1 NMR spectroscopy was applied for metabolic profiling of the anterior eye segment, specifically to analyse metabolic changes in intact corneal and lenticular samples after cataractogenic insults. This work included metabonomics with the application of pattern recognition methods to analyse HR-MAS spectra of eye tissues. Optimisation strategies were explored for F19 NMR detection of fluorinated drugs in a phantom eye. S/N gains in F19 NMR spectroscopy were achieved by implementing time-share H1 decoupling at 2.35 T. The method is advantageous for compounds displaying broad spectral coupling patterns, though detection of drugs at concentrations encountered in the anterior eye segment after topical application was not feasible. Higher magnetic fields and technological improvements could enable

  6. Gamma-ray spectroscopy of 120-130Te nuclei

    International Nuclear Information System (INIS)

    Complete text of publication follows. Structure of the even 120-130Te nuclei have been investigated with prompt gamma-ray spectroscopy following the 122-126,natTe(n,n'γ) reactions and the (α,2nγ)120,124,126Te reactions. Gamma-ray excitation functions, angular distributions, γγ-coincidences, and Doppler shifts have been measured. Level schemes have been constructed to approximately 3.3 MeV excitation energy, and spectroscopic information including level spins and parities, branching and multipole-mixing ratios, and lifetimes have been extracted. Three different types of structure are thought to play an important role in these low-lying excitations. These are: collective, two-particle, and 4p-2h intruder excitations. Because there are seven stable even-even Te nuclei, the evolution of these excitation modes over this wide range in neutron number is investigated. Level sequences and transition rates obtained from these measurements are compared to IBM-2 model calculations both with and without intruder-state mixing by Rikovska et al. (1), and to particle-vibrational coupling model calculations by Lopac (2). The IBM-2 model calculations with intruder mixing well reproduce the level energies in the low-mass Te; however, examination of the electromagnetic transition rates reveals that there is no clear improvement in the description of these nuclei by adding the intruder configurations. Additionally, no evidence of the 2+ mixed-symmetry strength is observed in the 23+ and 24+ levels in these nuclei. The particle-vibration model calculations appear to do a good job describing both the level scheme and the transition rates in the heavier nuclei investigated. (author)

  7. Rapid determination of soil contamination by helicopter gamma ray spectroscopy

    International Nuclear Information System (INIS)

    Specific aerial nuclide measurements of surface soil contamination were performed after the Chernobyl accident in the southern part of Germany. A helicopter equipped with a gamma ray spectroscopic system including a HPGe detector (50% relative efficiency) and 3 NaI(Tl)-detectors (volume 12 l) was used. A detailed description is given of the complete measuring system which can also be used for detection of gamma sources, e.g. radioactive fragments of nuclear powered satellites. At an altitude of 100 m, a soil contamination of several kBq/m2 for 134Cs and 137Cs can be measured for 60 s at a helicopter speed of 100 km/h. For detection of point gamma sources, the NaI(Tl)-detector was used. Assuming a line spacing of 300 m and a speed of 100 km/h, an area of about 30 km2 can be surveyed per hour. Thus 60Co-sources of some GBq activity can be detected. The system was practically applied for the first time for measuring the man-made radionuclides. The chosen distance between the routes was 10 km, and measuring time - 60 s for each spectrum corresponding to a flight path distance of about 2.2 km over which the average soil contamination was determined. The measured 137Cs values of up to 25 kBq/m2 are in good agreement with the results obtained by other methods (in-situ-spectrometry, measurements of soil samples). The aerial measuring system was also tested in the former USSR, in a region north of Chernobyl, with nuclide deposition values of up to 2 MBq/m2. 7 figs., 2 refs. (orig.)

  8. Decay Heat Measurements Using Total Absorption Gamma-ray Spectroscopy

    Science.gov (United States)

    Rice, S.; Valencia, E.; Algora, A.; Taín, J. L.; Regan, P. H.; Podolyák, Z.; Agramunt, J.; Gelletly, W.; Nichols, A. L.

    2012-09-01

    A knowledge of the decay heat emitted by thermal neutron-irradiated nuclear fuel is an important factor in ensuring safe reactor design and operation, spent fuel removal from the core, and subsequent storage prior to and after reprocessing, and waste disposal. Decay heat can be readily calculated from the nuclear decay properties of the fission products, actinides and their decay products as generated within the irradiated fuel. Much of the information comes from experiments performed with HPGe detectors, which often underestimate the beta feeding to states at high excitation energies. This inability to detect high-energy gamma emissions effectively results in the derivation of decay schemes that suffer from the pandemonium effect, although such a serious problem can be avoided through application of total absorption γ-ray spectroscopy (TAS). The beta decay of key radionuclei produced as a consequence of the neutron-induced fission of 235U and 239Pu are being re-assessed by means of this spectroscopic technique. A brief synopsis is given of the Valencia-Surrey (BaF2) TAS detector, and their method of operation, calibration and spectral analysis.

  9. CsI(Tl)-photodiode detectors for gamma-ray spectroscopy

    CERN Document Server

    Fioretto, E; Viesti, G; Cinausero, M; Zuin, L; Fabris, D; Lunardon, M; Nebbia, G; Prete, G

    2000-01-01

    We report on the performances of CsI(Tl)-photodiode detectors for gamma-ray spectroscopy applications. Light output yield and energy resolution have been measured for different crystals and read-out configurations.

  10. Photon-induced positron annihilation lifetime spectroscopy using ultrashort laser-Compton-scattered gamma-ray pulses

    Science.gov (United States)

    Taira, Y.; Toyokawa, H.; Kuroda, R.; Yamamoto, N.; Adachi, M.; Tanaka, S.; Katoh, M.

    2013-05-01

    High-energy ultrashort gamma-ray pulses can be generated via laser Compton scattering with 90° collisions at the UVSOR-II electron storage ring. As an applied study of ultrashort gamma-ray pulses, a new photon-induced positron annihilation lifetime spectroscopy approach has been developed. Ultrashort gamma-ray pulses with a maximum energy of 6.6 MeV and pulse width of 2.2 ps created positrons throughout bulk lead via pair production. Annihilation gamma rays were detected by a BaF2 scintillator mounted on a photomultiplier tube. A positron lifetime spectrum was obtained by measuring the time difference between the RF frequency of the electron storage ring and the detection time of the annihilation gamma rays. We calculated the response of the BaF2 scintillator and the time jitter caused by the variation in the total path length of the ultrashort gamma-ray pulses, annihilation gamma rays, and scintillation light using a Monte Carlo simulation code. The positron lifetime for bulk lead was successfully measured.

  11. Photon-induced positron annihilation lifetime spectroscopy using ultrashort laser-Compton-scattered gamma-ray pulses.

    Science.gov (United States)

    Taira, Y; Toyokawa, H; Kuroda, R; Yamamoto, N; Adachi, M; Tanaka, S; Katoh, M

    2013-05-01

    High-energy ultrashort gamma-ray pulses can be generated via laser Compton scattering with 90° collisions at the UVSOR-II electron storage ring. As an applied study of ultrashort gamma-ray pulses, a new photon-induced positron annihilation lifetime spectroscopy approach has been developed. Ultrashort gamma-ray pulses with a maximum energy of 6.6 MeV and pulse width of 2.2 ps created positrons throughout bulk lead via pair production. Annihilation gamma rays were detected by a BaF2 scintillator mounted on a photomultiplier tube. A positron lifetime spectrum was obtained by measuring the time difference between the RF frequency of the electron storage ring and the detection time of the annihilation gamma rays. We calculated the response of the BaF2 scintillator and the time jitter caused by the variation in the total path length of the ultrashort gamma-ray pulses, annihilation gamma rays, and scintillation light using a Monte Carlo simulation code. The positron lifetime for bulk lead was successfully measured. PMID:23742543

  12. Gamma-ray scatter methods applied to industrial measurement systems

    Energy Technology Data Exchange (ETDEWEB)

    Holstad, Marie Bueie

    2004-09-01

    Throughout the work presented in this dissertation it has been confirmed that the use of scattered gamma-radiation is a complex but useful tool in industrial measurement science. Scattered radiation has shown to be useful both when traditional measurement principles cannot be used (Chapter 4) and when more information about a system is needed than what is obtained with transmission measurements (Chapter 6). All three main projects (Chapters 4, 5 and 6) confirm that the sensitivity and accuracy of systems based on scattered gamma-radiation depends strongly on the geometry of the setup and that that presence of multiple scattered radiation makes the problems complex. Chapter 4 shows that multiple scattered gamma-radiation can be used for detection of changes in density where the dimensions are too large to use transmitted radiation. There is, however, an upper limit on the thickness of the absorbing medium also when scattered radiation is utilized. As seen in Chapter 5, multiple scattered gamma-radiation can in principle also be used in level gauges with very compact measurement geometries. The main challenges are the sensitivity to interfaces between materials with similar densities and low count rate. These challenges could not be overcome for level measurements in gravitational separator tanks. The results presented in Chapter 6 show that it is feasible to combine transmission and scatter measurements to characterize produced water in the oil and gas industry. (Author)

  13. Gamma-ray scatter methods applied to industrial measurement systems

    International Nuclear Information System (INIS)

    Throughout the work presented in this dissertation it has been confirmed that the use of scattered gamma-radiation is a complex but useful tool in industrial measurement science. Scattered radiation has shown to be useful both when traditional measurement principles cannot be used (Chapter 4) and when more information about a system is needed than what is obtained with transmission measurements (Chapter 6). All three main projects (Chapters 4, 5 and 6) confirm that the sensitivity and accuracy of systems based on scattered gamma-radiation depends strongly on the geometry of the setup and that that presence of multiple scattered radiation makes the problems complex. Chapter 4 shows that multiple scattered gamma-radiation can be used for detection of changes in density where the dimensions are too large to use transmitted radiation. There is, however, an upper limit on the thickness of the absorbing medium also when scattered radiation is utilized. As seen in Chapter 5, multiple scattered gamma-radiation can in principle also be used in level gauges with very compact measurement geometries. The main challenges are the sensitivity to interfaces between materials with similar densities and low count rate. These challenges could not be overcome for level measurements in gravitational separator tanks. The results presented in Chapter 6 show that it is feasible to combine transmission and scatter measurements to characterize produced water in the oil and gas industry. (Author)

  14. {gamma}-ray spectroscopy with a {sup 8}He beam

    Energy Technology Data Exchange (ETDEWEB)

    Podolyak, Zs. E-mail: z.podolyak@surrey.ac.uk; Walker, P.M.; Mach, H.; France, G. de; Sletten, G.; Azaiez, F.; Casandjian, J.M.; Cederwall, B.; Cullen, D.M.; Dombradi, Zs.; Dracoulis, G.D.; Fraile, L.M.; Franchoo, S.; Fynbo, H.; Gorska, M.; Kopatch, Y.; Lane, G.J.; Mandal, S.; Milechina, L.; Molnar, J.; O' Leary, C.; Plociennik, W.; Pucknell, V.; Raddon, P.; Redon, N.; Ruchowska, E.; Stanoiu, M.; Tengblad, O.; Wheldon, C.; Wood, R

    2003-10-01

    The {sup 8}He+{sup 208}Pb reaction was studied in the first experiment with the EXOGAM germanium detector array using beam delivered by the SPIRAL facility. {gamma}-rays from direct and fusion-evaporation reactions were observed with high resolution. {gamma}-{gamma} coincidence data were obtained at a beam intensity level of 10{sup 5} {sup 8}He particles per second. Specially designed absorbers and beam detectors could further reduce the background radiation by orders of magnitude.

  15. Delayed Gamma-Ray Spectroscopy for Non-Destructive Assay of Nuclear Materials

    International Nuclear Information System (INIS)

    High-energy, beta-delayed gamma-ray spectroscopy is a potential, non-destructive assay techniques for the independent verification of declared quantities of special nuclear materials at key stages of the fuel cycle and for directly assaying nuclear material inventories for spent fuel handling, interim storage, reprocessing facilities, repository sites, and final disposal. Other potential applications include determination of MOX fuel composition, characterization of nuclear waste packages, and challenges in homeland security and arms control verification. Experimental measurements were performed to evaluate fission fragment yields, to test methods for determining isotopic fractions, and to benchmark the modeling code package. Experimental measurement campaigns were carried out at the IAC using a photo-neutron source and at OSU using a thermal neutron beam from the TRIGA reactor to characterize the emission of high-energy delayed gamma rays from 235U, 239Pu, and 241Pu targets following neutron induced fission. Data were collected for pure and combined targets for several irradiation/spectroscopy cycle times ranging from 10/10 seconds to 15/30 minutes.The delayed gamma-ray signature of 241Pu, a significant fissile constituent in spent fuel, was measured and compared to 239Pu. The 241Pu/239Pu ratios varied between 0.5 and 1.2 for ten prominent lines in the 2700-3600 keV energy range. Such significant differences in relative peak intensities make it possible to determine relative fractions of these isotopes in a mixed sample. A method for determining fission product yields by fitting the energy and time dependence of the delayed gamma-ray emission was developed and demonstrated on a limited 235U data set. De-convolution methods for determining fissile fractions were developed and tested on the experimental data. The use of high count-rate LaBr3 detectors was investigated as a potential alternative to HPGe detectors. Modeling capabilities were added to an existing

  16. Delayed Gamma-Ray Spectroscopy for Non-Destructive Assay of Nuclear Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ludewigt, Bernhard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mozin, Vladimir [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Campbell, Luke [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Favalli, Andrea [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hunt, Alan W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Reedy, Edward T.E. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Seipel, Heather [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-06-01

    High-­energy, beta-delayed gamma-­ray spectroscopy is a potential, non-­destructive assay techniques for the independent verification of declared quantities of special nuclear materials at key stages of the fuel cycle and for directly assaying nuclear material inventories for spent fuel handling, interim storage, reprocessing facilities, repository sites, and final disposal. Other potential applications include determination of MOX fuel composition, characterization of nuclear waste packages, and challenges in homeland security and arms control verification. Experimental measurements were performed to evaluate fission fragment yields, to test methods for determining isotopic fractions, and to benchmark the modeling code package. Experimental measurement campaigns were carried out at the IAC using a photo-­neutron source and at OSU using a thermal neutron beam from the TRIGA reactor to characterize the emission of high-­energy delayed gamma rays from 235U, 239Pu, and 241Pu targets following neutron induced fission. Data were collected for pure and combined targets for several irradiation/spectroscopy cycle times ranging from 10/10 seconds to 15/30 minutes.The delayed gamma-ray signature of 241Pu, a significant fissile constituent in spent fuel, was measured and compared to 239Pu. The 241Pu/239Pu ratios varied between 0.5 and 1.2 for ten prominent lines in the 2700-­3600 keV energy range. Such significant differences in relative peak intensities make it possible to determine relative fractions of these isotopes in a mixed sample. A method for determining fission product yields by fitting the energy and time dependence of the delayed gamma-­ray emission was developed and demonstrated on a limited 235U data set. De-­convolution methods for determining fissile fractions were developed and tested on the experimental data. The use of high count-­rate LaBr3 detectors

  17. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1968-01-01

    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  18. Computers in activation analysis and gamma-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, B. S.; D' Agostino, M. D.; Yule, H. P. [eds.

    1979-01-01

    Seventy-three papers are included under the following session headings: analytical and mathematical methods for data analysis; software systems for ..gamma..-ray and x-ray spectrometry; ..gamma..-ray spectra treatment, peak evaluation; least squares; IAEA intercomparison of methods for processing spectra; computer and calculator utilization in spectrometer systems; and applications in safeguards, fuel scanning, and environmental monitoring. Separate abstracts were prepared for 72 of those papers. (DLC)

  19. The Northern Marshall Islands radiological survey: A quality control program for radiochemical and gamma spectroscopy analysis

    International Nuclear Information System (INIS)

    From 1979 to 1989, approximately 25,000 Post Northern Marshall Islands Radiological Survey (PNMIRS) samples were collected, and over 71,400 radiochemical and gamma spectroscopy analyses were performed to establish the concentration of 90Sr, 137Cs, 241Am, and plutonium isotopes in soil, vegetation, fish, and animals in the Northern Marshall Islands. While the Low Level Gamma Counting Facility (B379) in the Health and Ecological Assessment (HEA) division accounted for over 80% of all gamma spectroscopy analyses, approximately 4889 radiochemical and 5437 gamma spectroscopy analyses were performed on 4784 samples of soil, vegetation, terrestrial animal, and marine organisms by outside laboratories. Four laboratories were used by Lawrence Livermore National Laboratory (LLNL) to perform the radiochemical analyses: Thermo Analytical Norcal, Richmond, California (TMA); Nuclear Energy Services, North Carolina State University (NCSU); Laboratory of Radiation Ecology, University of Washington (LRE); and Health and Ecological Assessment (HEA) division, LLNL, Livermore, California. Additionally, LRE and NCSU were used to perform gamma spectroscopy analyses. The analytical precision and accuracy were monitored by including blind duplicates and natural matrix standards in each group of samples analyzed. On the basis of reported analytical values for duplicates and standards, 88% of the gamma and 87% of the radiochemical analyses in this survey were accepted. By laboratory, 93% of the radiochemical analyses by TMA; 88% of the gamma-ray spectrometry and 100% of the radiochemistry analyses by NCSU; 89% of the gamma spectroscopy and 87% of the radiochemistry analyses by LRE; and 90% of the radiochemistry analyses performed by HEA's radiochemistry department were accepted

  20. Neutron counting and gamma spectroscopy with PVT detectors.

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Dean James; Brusseau, Charles A.

    2011-06-01

    Radiation portals normally incorporate a dedicated neutron counter and a gamma-ray detector with at least some spectroscopic capability. This paper describes the design and presents characterization data for a detection system called PVT-NG, which uses large polyvinyl toluene (PVT) detectors to monitor both types of radiation. The detector material is surrounded by polyvinyl chloride (PVC), which emits high-energy gamma rays following neutron capture reactions. Assessments based on high-energy gamma rays are well suited for the detection of neutron sources, particularly in border security applications, because few isotopes in the normal stream of commerce have significant gamma ray yields above 3 MeV. Therefore, an increased count rate for high-energy gamma rays is a strong indicator for the presence of a neutron source. The sensitivity of the PVT-NG sensor to bare {sup 252}Cf is 1.9 counts per second per nanogram (cps/ng) and the sensitivity for {sup 252}Cf surrounded by 2.5 cm of polyethylene is 2.3 cps/ng. The PVT-NG sensor is a proof-of-principal sensor that was not fully optimized. The neutron detector sensitivity could be improved, for instance, by using additional moderator. The PVT-NG detectors and associated electronics are designed to provide improved resolution, gain stability, and performance at high-count rates relative to PVT detectors in typical radiation portals. As well as addressing the needs for neutron detection, these characteristics are also desirable for analysis of the gamma-ray spectra. Accurate isotope identification results were obtained despite the common impression that the absence of photopeaks makes data collected by PVT detectors unsuitable for spectroscopic analysis. The PVT detectors in the PVT-NG unit are used for both gamma-ray and neutron detection, so the sensitive volume exceeds the volume of the detection elements in portals that use dedicated components to detect each type of radiation.

  1. Determination of small contents of Zn, Pb and K in soil samples from Bielice Tatrzanskie by means of PIXE, AAS and gamma spectroscopy

    International Nuclear Information System (INIS)

    The aim of his work was the comparison of analytical techniques applied to determination of Pb, Zn and K in soil samples from Tatra mountains. The analyses were performed by three different analytical techniques such as: PIXE (proton Induced x-ray Emission) AAS (Atomic Absorption Spectroscopy) and gamma spectroscopy. The measurements done with those techniques allow to determine the content of Pb, Zn and K within statistical error proving correctness of those determinations. (author)

  2. Gamma Ray Spectroscopy with Scintillation Light in Liquid Xenon

    CERN Document Server

    Ni, K; Giboni, K L; Majewski, P; Yamashita, M

    2006-01-01

    Scintillation light from gamma ray irradiations in liquid xenon is detected by two Hamamatsu R9288 photomultiplier tubes (PMTs) immersed in the liquid. UV light reflector material, PTFE, is used to optimize the light collection efficiency. The detector gives a high light yield of 6 photoelectron per keV (pe/keV), which allows efficient detection of the 122 keV gamma-ray line from Co-57, with a good measured energy resolution at (8.8+/-0.6)% (sigma). The best achievable energy resolution from liquid xenon scintillation light is estimated to be around 6-8% (sigma) for gamma-ray with energy between 662 keV and 122 keV.

  3. A practical approach to handling the uncertainty analysis in gamma spectroscopy with the software's Gamma Vision and Genie

    International Nuclear Information System (INIS)

    Full text: The national Swedish network of laboratories in emergency response and preparedness should provide with fast and reliable measurements. That is why these results should be given with a measure of its quality, which is the measurement uncertainty, as has been stated in several international standards. Many gamma spectroscopy software packages contain advance algorithms for calculation of the activity and its measurement uncertainty. They even include elements of quality assurance and quality control. Despite of that, not all sources of uncertainty are always taken into account. The two most used analysis software packages in the Swedish network of laboratories in emergency response are Gamma Vision from Ortec and Genie (with and without APEX) from Canberra. The purpose of this paper is to present two groups of practical evaluations of uncertainty components for the same kind of gamma-spectroscopy analysis, one that would suit Gamma Vision users and other for Genie users, including the Labsocs tool. The main idea is to profit as much as possible of the software capabilities and semi-manually add the contribution of uncertainty sources that are not been taken into account. The reports from both the software packages are modified so as to reflect the contribution of all sources of uncertainty into the reported relative combined uncertainty. The examples of gamma spectroscopy analysis are for samples of the same matrix and the different geometries foreseen in the context of emergency response by the Swedish emergency network. Together with the evaluation of the uncertainty components a review on the uncertainty propagation and the assumptions taken in each of the software packages is presented. (author)

  4. A simple technique for gamma ray and cosmic ray spectroscopy using plastic scintillator

    Science.gov (United States)

    Nandan, Akhilesh P.; Rudra, Sharmili; Neog, Himangshu; Biswas, S.; Mahapatra, S.; Mohanty, B.; Samal, P. K.

    2016-07-01

    A new and simple technique has been developed using plastic scintillator detectors for gamma ray and cosmic ray spectroscopy without single channel analyzer (SCA) or multichannel analyzer (MCA). In these experiments only a leading edge discriminator (LED) and NIM scalers have been used. Energy calibration of gamma spectra in plastic scintillators has been done using Co60 and Cs137 sources. The details of the experimental technique, analysis procedure and experimental results have been presented in this paper.

  5. Determining gamma dose rates by field gamma spectroscopy in sedimentary media: Results of Monte Carlo simulations

    International Nuclear Information System (INIS)

    Field gamma spectrometers are widely used to determine gamma dose rates in sedimentary media. However the most widely used technique-the 'window technique'-is time consuming and introduces important statistical uncertainty in the determination of the radioelement contents, and finally on the gamma dose rate. The threshold technique directly relates the number of counts recorded above certain threshold energy to the gamma dose rate. Recently new experimental measurements further investigated this technique but it has not been tested in various sedimentary media. In this paper, numerical simulations using a specifically designed Geant4 code allow to test the sensitivity of this technique to changes of sediments nature, humidity content and disequilibrium in the U-series. Finally another threshold technique, relating the gamma dose rate to the energy per unit time deposited above another threshold energy, is investigated. It is shown than the latter has a number of advantages compared to the classical techniques. Experimental results testing this approach are presented.

  6. GRIPS - Gamma-Ray Imaging, Polarimetry and Spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Greiner, J.; Mannheim, K.; Hudec, René; Mészáros, A.

    2012-01-01

    Roč. 34, č. 2 (2012), s. 551-582. ISSN 0922-6435 Institutional research plan: CEZ:AV0Z10030501 Keywords : compton and pair creation telescope * gamma-ray bursts * nucleosynthesis Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 2.969, year: 2012

  7. Gamma-ray spectroscopy of neutron-rich products of heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, M.P.; Janssens, R.V.F.; Ahmad, I. [and others

    1995-08-01

    Thick-target {gamma}{gamma} coincidence techniques are being used to explore the spectroscopy of otherwise hard-to-reach neutron-rich products of deep-inelastic heavy ion reactions. Extensive {gamma}{gamma} coincidence measurements were performed at ATLAS using pulsed beams of {sup 80}Se, {sup 136}Xe, and {sup 238}U on lead-backed {sup 122,124}Sn targets with energies 10-15% above the Coulomb barrier. Gamma-ray coincidence intensities were used to map out yield distributions with A and Z for even-even product nuclei around the target and around the projectile. The main features of the yield patterns are understandable in terms of N/Z equilibration. We had the most success in studying the decays of yrast isomers. Thus far, more than thirty new {mu}s isomers in the Z = 50 region were found and characterized. Making isotopic assignments for previously unknown {gamma}-ray cascades proves to be one of the biggest problems. Our assignments were based (a) on rare overlaps with radioactivity data, (b) on the relative yields with different beams, and (c) on observed cross-coincidences between {gamma} rays from light and heavy reaction partners. However, the primary products of deep inelastic collisions often are sufficiently excited for subsequent neutron evaporation, so {gamma}{gamma} cross-coincidence results require careful interpretation.

  8. Gamma-irradiated ExtraVit M nutritive supplement studied by electron paramagnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Petrisor, Dina [Faculty of Physics, Babes-Bolyai University, 1A Kogalniceanu Street, 400084 Cluj-Napoca (Romania)], E-mail: dinapetrisor@yahoo.co.uk; Damian, Grigore; Simon, Simion [Faculty of Physics, Babes-Bolyai University, 1A Kogalniceanu Street, 400084 Cluj-Napoca (Romania)

    2008-04-15

    An unirradiated and {gamma}-irradiated nutritive supplement named ExtraVit M was studied by electron paramagnetic resonance (EPR) spectroscopy in order to detect stable paramagnetic species following improvement of hygienic quality by {gamma}-radiation. Free radicals were induced by {gamma}-radiation in the studied samples from low absorbed doses, showing a certain sensibility of these samples to the radiation treatment. The EPR spectrum of irradiated ExtraVit M is typical for drugs or nutritive supplements containing high levels of sugars, vitamin C and cellulose.

  9. Radiation detection system for portable gamma-ray spectroscopy

    Science.gov (United States)

    Rowland, Mark S.; Howard, Douglas E.; Wong, James L.; Jessup, James L.; Bianchini, Greg M.; Miller, Wayne O.

    2006-06-20

    A portable gamma ray detection apparatus having a gamma ray detector encapsulated by a compact isolation structure having at least two volumetrically-nested enclosures where at least one is a thermal shield. The enclosures are suspension-mounted to each other to successively encapsulate the detector without structural penetrations through the thermal shields. A low power cooler is also provided capable of cooling the detector to cryogenic temperatures without consuming cryogens, due to the heat load reduction by the isolation structure and the reduction in the power requirements of the cooler. The apparatus also includes a lightweight portable power source for supplying power to the apparatus, including to the cooler and the processing means, and reducing the weight of the apparatus to enable handheld operation or toting on a user's person.

  10. The ''RB'' reactor uranium fuel enrichment verification by gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    Gamma spectrometry analysis of natural and 2% enriched uranium metal fuel at the RB reactor was performed by germanium gamma spectrometer applying developed computer code ANA. Different samples of the RB reactor uranium fuel, placed at various distances from the Ge detector, were used during measurements. Gamma-ray self-absorption in the fuel material and the geometrical corrections were included in the calculation performed by computer code EFI based on a Monte Carlo method. Evaluated experimental data were used to determine branching ratio for the 1001 keV gamma line of 234mPa which is in equilibrium with 238U. Obtained results were in good agreement with the results of other authors. Applied gamma spectrometry method is used for examination of the fresh fuel composition and validation of isotopic enrichment of the 2% enriched uranium fuel at the RB reactor. (author)

  11. Quantification of 235 U and 226 Ra in soil samples by means of Gamma spectroscopy

    International Nuclear Information System (INIS)

    In this work it is presented the Gamma Spectroscopy method which is realized in the Environmental Radiological Surveillance Laboratory using the option of deconvolution of a commercial software for the quantification of 235 U and 226 Ra; also is presented the method for the 226 Ra correction activity. (Author)

  12. Simple data processing for gamma spectroscopy in activation analysis

    International Nuclear Information System (INIS)

    A data processing system was developed for multielement neutron activation analysis. It uses a desk-top programmable calculator that is operated off line. The processing is divided into two main programs. The first one detects the peaks of a series of gamma spectra with a 0.1-keV accuracy. The second program performs the integration of peaks selected by the operator, including those for which he wants a detection limit. Peak intensities corrected for decay and dead time are calculated. This system has many advantages: easy use, great versatility, large possibilities for manual control, and low cost

  13. Development of Magnetic Microcalorimeters for Gamma-Ray Spectroscopy

    Science.gov (United States)

    Le, L. N.; Hummatov, R.; Hall, J. A.; Cantor, R. C.; Boyd, S. T. P.

    2016-01-01

    Integrating the SQUIDs and sensing coils of magnetic microcalorimeters onto the same die is a promising approach for maximizing flux coupling and signal/noise. However, new challenges in microfabrication must be overcome, because the underlying SQUID devices are sensitive to chemical attack and elevated processing temperatures. In this report, we describe development and details of a microfabrication process for integrated SQUID/sensor gamma-ray magnetic microcalorimeters with electroformed gold absorbers, starting from a modified version of the STAR Cryoelectronics "Delta 1000" Josephson Junction process.

  14. Development of Magnetic Microcalorimeters for Gamma-Ray Spectroscopy

    Science.gov (United States)

    Le, L. N.; Hummatov, R.; Hall, J. A.; Cantor, R. C.; Boyd, S. T. P.

    2016-07-01

    Integrating the SQUIDs and sensing coils of magnetic microcalorimeters onto the same die is a promising approach for maximizing flux coupling and signal/noise. However, new challenges in microfabrication must be overcome, because the underlying SQUID devices are sensitive to chemical attack and elevated processing temperatures. In this report, we describe development and details of a microfabrication process for integrated SQUID/sensor gamma-ray magnetic microcalorimeters with electroformed gold absorbers, starting from a modified version of the STAR Cryoelectronics "Delta 1000" Josephson Junction process.

  15. A gamma-ray spectroscopy survey of Omani meteorites

    CERN Document Server

    Weber, Patrick; Tolba, Tamer; Vuilleumier, Jean-Luc

    2016-01-01

    The gamma-ray activities of 33 meteorite samples (30 ordinary chondrites, 1 Mars meteorite, 1 iron, 1 howardite) collected during Omani-Swiss meteorite search campaigns 2001-2008 were nondestructively measured using an ultra-low background gamma-ray detector. The results provide several types of information: Potassium and thorium concentrations were found to range within typical values for the meteorite types. Similar mean 26Al activities in groups of ordinary chondrites with a) weathering degrees W0-1 and low 14C terrestrial age and b) weathering degree W3-4 and high 14C terrestrial age are mostly consistent with activities observed in recent falls. The older group shows no significant depletion in 26Al. Among the least weathered samples two meteorite were found to contain clearly detectable 22Na indicating they are recent falls. Based on an estimate of the surface area searched, the corresponding fall rate is <120 events/106 km2*a, consistent with estimated fall rates. 12 samples from the large JaH 091 s...

  16. Optical spectroscopy of Be/gamma-ray binaries

    CERN Document Server

    Zamanov, R K; Marti, J; Latev, G Y; Nikolov, Y M; Bode, M F; Luque-Escamilla, P L

    2016-01-01

    We report optical spectroscopic observations of the gamma-ray binaries LSI+61303, MWC 656, MWC 148. The peak separation and equivalent widths of prominent emission lines (H-alpha, H-beta, H-gamma, HeI and FeII) are measured. We estimate the circumstellar disc size, compare it with separation between the components and discuss the disc truncation. We find that in LSI+61303 the compact object comes into contact with the outer parts of the circumstellar disc at periastron; in MWC 148 the compact object goes deeply into the disc during the periastron passage, and in MWC 656 the black hole is accreting from the outer parts of the circumstellar disc along the entire orbit. The interstellar extinction is estimated using interstellar lines and hydrogen column density. The rotation of the mass donors appears to be similar to the rotation of the mass donors in Be/X-ray binaries. We suggest that X-ray periodicity ~1 day deserves to be searched for.

  17. A segmented detector for airbone gamma ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Burgada, G.; Iovene, A.; Petrucci, S.; Tintori, C., E-mail: g.burgada@caen.it [Costruzioni Apparecchiature Elettroniche Nucleari S.p.A. (CAEN), Viareggio (Italy); Alvarez, M.A.G., E-mail: malvarez@if.usp.br [Universidade de Sao Paulo (IF/USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Baldoncini, M.; Xhixha, G.; Strati, V., E-mail: gerti.xhixha@unife.it [University of Ferrara, Department of Physics and Earth Sciences, Ferrara (Italy); Mantovani, F., E-mail: mantovani@fe.infn.it [Istituto Nazionale di Fisica Nucleare (INFN), Ferrara (Italy); Garosi, P.; Mou, L., E-mail: li.mou@libero.it [University of Siena (Italy); Alvarez, C. Rossi, E-mail: rossialvarez@pd.infn.it [Istituto Nazionale di Fisica Nucleare (INFN), Legnaro (Italy)

    2014-07-01

    The airborne gamma-ray spectrometry (AGRS) is widely acknowledged as a very efficient technique for large areas monitoring. The detector system mounted on a helicopter allows for an extensive survey in a single flight time, thus reducing the exposure risk for the operator. Results from AGRS techniques are exploited in many fields, from the geological research to the homeland security for the search of orphan radioactive sources, from the mining and hydrocarbon exploration to the construction industry. The new generation of compact digital data acquisition and online processing equipment allows for faster airborne survey campaigns, and enhances the flexibility of operations. In addition, the algorithm for the extrapolation of the nuclide concentrations from the acquired gamma spectra is a challenging step of the entire technique. We are going to present a new device for advanced AGRS measurements, with an innovative detector configuration and data processing algorithms for optimizing the source localization and the on-line response capabilities. The new compact structure makes the system easily portable by a single operator, and rapidly mountable on most common helicopters. Preliminary feasibility studies have been performed to test the mechanics and the hardware of the whole system, which is intended to work without any human attendance. The first flights are planned by the end of 2014, with the aim of detecting artificial point sources having intensities on the order of 10^8 Bq and natural enriched fields already monitored. (author)

  18. UV spectroscopy applied to stratospheric chemistry, methods and results

    Energy Technology Data Exchange (ETDEWEB)

    Karlsen, K.

    1996-03-01

    The publication from the Norwegian Institute for Air Research (NILU) deals with an investigation done on stratospheric chemistry by UV spectroscopy. The scientific goals are briefly discussed, and it gives the results from the measuring and analysing techniques used in the investigation. 6 refs., 11 figs.

  19. Instructions for calibrating gamma detectors using the Canberra-Nuclear Data Genie Gamma Spectroscopy System

    International Nuclear Information System (INIS)

    A straight forward protocol provides a way to guide the calibration of a gamma detector for a particular geometry and material. Several programs have used the Low Level Gamma Counting Facility of the Health and Ecological Assessment Division of the Lawrence Livermore National Laboratory to count a variety of large environmental samples contained in several unique geometries. The equipment and calibration requirements needed to analyze these types of samples are explained. This document describes the calibration protocol that has been developed and describes how it is used to calibrate the detectors

  20. Scanning electron microscopy and X-ray spectroscopy applied to mycelial phase of sporothrix schenckii

    Directory of Open Access Journals (Sweden)

    M. Thibaut

    1975-04-01

    Full Text Available Scanning electron microscopy applied to the mycelial phase of Sporothrix schenckii shows a matted mycelium with conidia of a regular pattern. X-Ray microanalysis applied in energy dispersive spectroscopy and also in wavelength dispersive spectroscopy reveals the presence of several elements of Mendeleef's classification.

  1. A high counting rate scintillation gamma spectrometer for Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    A scintillation gamma spectrometer stabilized by a feedback equipped with a reference light pulses source, a pulse generator (10 to 100 Hz) and a pile-up rejecter is proposed. The pile-up of light pulses on scintillation ones are eliminated by delaying the reference pulse start till the end of the scintillation pulse. If a scintillation pulse appears before the end of the reference pulse, the measured reference pulse amplitude value is ignored. The reference pulse amplitudes are measured by differential discriminator. If the reference light pulse amplitude is lower or higher than the discriminator window, the content of the up-down counter increases or decreases, respectively. A digital-to-analog converters produces an analogous signal, which controls the photomultiplier high voltage supply. The spectrometer operates at counting rates below 450 000 pulses/sec. (author)

  2. In-beam gamma-ray spectroscopy of 82Sr

    International Nuclear Information System (INIS)

    The reaction 70Ge(16O,2p2n)82Sr with E(16O) = 80 MeV was used to study the nucleus 82Sr. Measurements were made of the excitation functions, angular distributions, and γ-γ-t coincidences. From these measurements six new levels were placed in the level scheme of 82Sr at 2683.7, 3609.2, 4367.1, 5308.4, 6364.4, and 7827.8 keV. A gamma ray with a very high anisotropy [A2 = -1.05(7), A4 = 0.12(6)] feeds the (11-) level at 5914.5 keV. A new band based on the level at 3525.7 keV was identified. The sequence of transitions decaying down the negative parity band was reordered to 522-1005-876-694 keV

  3. In-beam gamma-ray spectroscopy of YSSr

    Energy Technology Data Exchange (ETDEWEB)

    Haskins, P.S.; Dunnam, F.E.; Coldwell, R.L.; Rester, A.C.; Piercey, R.B.; Muga, M.L.; Van Rinsvelt, H.A.; Smart, R.W.; Aarts, H.J.M.

    1985-12-01

    The reaction XGe( WO,2p2n)YSSr with E( WO) = 80 MeV was used to study the nucleus YSSr. Measurements were made of the excitation functions, angular distributions, and el-el-t coincidences. From these measurements six new levels were placed in the level scheme of YSSr at 2683.7, 3609.2, 4367.1, 5308.4, 6364.4, and 7827.8 keV. A gamma ray with a very high anisotropy (A2 = -1.05(7), A4 = 0.12(6)) feeds the (11 ) level at 5914.5 keV. A new band based on the level at 3525.7 keV was identified. The sequence of transitions decaying down the negative parity band was reordered to 522-1005-876-694 keV.

  4. Gamma spectroscopy analysis of archived Marshall Island soil samples

    International Nuclear Information System (INIS)

    Four samples of archival Marshall Islands soil were subjected to non-destructive, broad energy (17 keV-2.61 MeV) gamma-ray spectrometry analysis using a series of different high-resolution germanium detectors. These archival samples were collected in 1967 from different locations on Bikini Atoll and were contaminated with a range of fission and activation products, and other nuclear material from multiple weapons tests. Unlike samples collected recently, these samples have been stored in sealed containers and have been unaffected by approximately 50 years of weathering. Initial results show that the samples contained measurable but proportionally different concentrations of plutonium, 241Am, and 137Cs, and 60Co. (author)

  5. Prompt gamma ray-spectroscopy of N = 50 fission fragments

    International Nuclear Information System (INIS)

    Excited states in the nuclei 83As and 84,86Se have been studied via prompt γ-ray spectroscopy. The nuclei were produced by the proton-induced fission of a 238U target, at the accelerator of the University of Jyvaeskylae. The JUROGAM-II array was used to detect prompt γ-rays and a triple- coincidence analysis performed. A comparison of the N = 50 nuclei with shell-model calculations reproduces the low-lying states in 83As and 84Se well. The inclusion of particle-hole excitations is necessary to correctly describe the states above ∼3.5 MeV. (authors)

  6. New Approach to Ultrasonic Spectroscopy Applied to Flywheel Rotors

    Science.gov (United States)

    Harmon, Laura M.; Baaklini, George Y.

    2002-01-01

    Flywheel energy storage devices comprising multilayered composite rotor systems are being studied extensively for use in the International Space Station. A flywheel system includes the components necessary to store and discharge energy in a rotating mass. The rotor is the complete rotating assembly portion of the flywheel, which is composed primarily of a metallic hub and a composite rim. The rim may contain several concentric composite rings. This article summarizes current ultrasonic spectroscopy research of such composite rings and rims and a flat coupon, which was manufactured to mimic the manufacturing of the rings. Ultrasonic spectroscopy is a nondestructive evaluation (NDE) method for material characterization and defect detection. In the past, a wide bandwidth frequency spectrum created from a narrow ultrasonic signal was analyzed for amplitude and frequency changes. Tucker developed and patented a new approach to ultrasonic spectroscopy. The ultrasonic system employs a continuous swept-sine waveform and performs a fast Fourier transform on the frequency spectrum to create the spectrum resonance spacing domain, or fundamental resonant frequency. Ultrasonic responses from composite flywheel components were analyzed at Glenn to assess this NDE technique for the quality assurance of flywheel applications.

  7. Structure of neutron-deficient nuclei by gamma spectroscopy. Resume of Ph.D thesis

    International Nuclear Information System (INIS)

    This is an extended abstract of the Ph. D. thesis devoted to the experimental study by in-beam gamma spectroscopy of the neutron-deficient nuclei 111 Sb and 146 Nd. The experimental investigation of these nuclei implied the following measurements: 1. in-beam activations; 2. cross reactions; 3. excitation functions; 4. charged-particle - gamma; 5. neutron - gamma coincidences; 6. γ-γ coincidences; 7. lifetime determinations; 8. gated-angular distributions 9. angular correlations. Original contributions concerning lifetime determination through the time centroid shift method, interpretation of double angular correlations of gamma rays emitted from oriented sources and a quasi-complete program package for processing and interpretation of in-beam gamma spectroscopy data are given. The nuclear data and shape coexistence in the 111 Sb nucleus are reported for the first time. The nuclear level scheme of 146 Nd was greatly extended, reaching levels as high as E ∼ 7.5 MeV, and Jπ = (22+). Also in the case of this nucleus the coexistence of mirror symmetric and asymmetric states was evidenced. The data were interpreted both in the frame of deformed mean field model and IBA model. (M.I.C.). 5 Figs., 3 Tabs., 35 Refs

  8. Laser induced breakdown spectroscopy (LIBS) applied to plutonium analysis

    International Nuclear Information System (INIS)

    A Laser Induced Breakdown Spectroscopy (LIBS) system has been developed specifically for the quantitative analysis of gallium in plutonium dioxide in support of the MOX fuel development program. The advantage of this system is no sample preparation and the capability to analyze extremely small samples. Success in this application has prompted an expansion of the technique to other areas, including determination of plutonium isotopic ratios. This paper will present recent results for gallium content in PuO2 after processing via thermally induced gallium removal (TIGR). Data will also be presented for the determination of the plutonium 239/240 isotopic ratio

  9. Digital Signal Processing for Optimal Resolution in Gamma Ray Spectroscopy

    International Nuclear Information System (INIS)

    The work described in this paper is based on the digital processing of samples obtained by digitizing the signal pulse as it appears at the output of a γ ray measuring set-up. Consequently, we will discuss the design as well as the implementation on a DSP board, of the various used digital pulse processing techniques in order to provide the main functions required in a generic ''Gamma'' digital spectroscopic set-up. The first part will be devoted to the design of the digital IIR filter used to compensate the charge preamplifier's slow pole. It will be followed by a practical estimation of the power spectral density characterizing the electrical noise components present in the experiment under consideration. Thereafter, a very detailed attention will be given to the design of the digital optimal filter to be used for the charge measurements. After, we present also another FIR filter. This one deals with the digital estimation of the measurement's reference line in a manner to achieve the role of the classical Base Line Restorer. Finally, we will present the hardware implementation of the whole designed filters using the board: ''TMS320C6713-DSK'', which is a DSP kit developed by ''DIGITAL Spectrum''. (author)

  10. Identification of gamma-irradiated fruit juices by EPR spectroscopy

    International Nuclear Information System (INIS)

    The results of electron paramagnetic resonance (EPR) study on commercially available juices from various fruits and different fruit contents: 25%, 40%, 50%, and 100%, homemade juices, nectars and concentrated fruit syrups, before and after gamma-irradiation are reported. In order to remove water from non- and irradiated samples all juices and nectars were filtered; the solid residue was washed with alcohol and dried at room temperature. Only concentrated fruit syrups were dried for 60 min at 40 °C in a standard laboratory oven. All samples under study show a singlet EPR line with g=2.0025 before irradiation with exception of concentrated fruit syrups, which are EPR silent. Irradiation of juice samples gives rise to complex EPR spectra which gradually transferred to “cellulose-like” EPR spectrum from 25% to 100% fruit content. Concentrated fruit syrups show typical “sugar-like“ spectra due to added saccharides. All EPR spectra are characteristic and can prove radiation treatment. The fading kinetics of radiation-induced EPR signals were studied for a period of 60 days after irradiation. - Highlights: • The EPR analysis of juices, nectars and syrups proves that the sample has been irradiated. • Two sample preparation procedures were used. • The stability of the radiation induced EPR signals was studied over 2 months. • Application of European standards can be extended for irradiated juices and syrups

  11. Electrochemical impedance spectroscopy based-on interferon-gamma detection

    Science.gov (United States)

    Li, Guan-Wei; Kuo, Yi-Ching; Tsai, Pei-I.; Lee, Chih-Kung

    2014-03-01

    Tuberculosis (TB) is an ancient disease constituted a long-term menace to public health. According to World Health Organization (WHO), mycobacterium tuberculosis (MTB) infected nearly a third of people of the world. There is about one new TB occurrence every second. Interferon-gamma (IFN-γ) is associated with susceptibility to TB, and interferongamma release assays (IGRA) is considered to be the best alternative of tuberculin skin test (TST) for diagnosis of latent tuberculosis infection (LTBI). Although significant progress has been made with regard to the design of enzyme immunoassays for IFN-γ, adopting this assay is still labor-intensive and time-consuming. To alleviate these drawbacks, we used IFN-γ antibody to facilitate the detection of IFN-γ. An experimental verification on the performance of IGRA was done in this research. We developed two biosensor configurations, both of which possess high sensitivity, specificity, and rapid IFN-γ diagnoses. The first is the electrochemical method. The second is a circular polarization interferometry configuration, which incorporates two light beams with p-polarization and s-polarization states individually along a common path, a four photo-detector quadrature configuration to arrive at a phase modulated ellipsometer. With these two methods, interaction between IFN-γ antibody and IFN-γ were explored and presented in detail.

  12. Verification of gamma-spectroscopy programs. N42.14 and beyond

    International Nuclear Information System (INIS)

    The American National Standard 'Calibration and Use of Germanium Spectrometers for the Measurement of Gamma-Ray Emission Rates of Radionuclides' has been reissued as N42.14-1999. The performance tests in it can be used to make sure that a gamma-spectroscopy program is set up correctly. The same tests can also be used to verify the improvements made by program developers. However, sometimes the tests in this ANSI standard are not enough. To satisfy certain quality assurance requirements, it is necessary to demonstrate that the results are correct either by hand calculations or by comparing the results to known values. (author)

  13. Study concerning the possibility of gamma-spectroscopy method to determining the total potassium in soils

    International Nuclear Information System (INIS)

    The paper presents the results of scientific research related to development the specifically express-method for determining total potassium in podsolic soils from Belarus and chernozem from Moldova, based on the use of gamma-spectrometry. Determining the precise of the total content of potassium in the soils can be made directly in the field or laboratory by gamma-spectroscopy method using radiation detection of natural isotope 40K. The conversion coefficient for podsolic soils of Belarus is C=0,00395, for chernozem of Moldova - C=0,00337. (authors)

  14. Combined in-beam gamma-ray and conversion electron spectroscopy with radioactive ion beams

    Directory of Open Access Journals (Sweden)

    Konki J.

    2013-12-01

    Full Text Available In-beam gamma-ray and electron spectroscopy have been widely used as tools to study the broad variety of phenomena in nuclear structure. The SPEDE spectrometer is a new device to be used in conjunction with the MINIBALL germanium detector array to enable the detection of internal conversion electrons in coincidence with gamma rays from de-exciting nuclei in radioactive ion beam experiments at the upcoming HIE-ISOLDE facility at CERN, Switzerland. Geant4 simulations were carried out in order to optimise the design and segmentation of the silicon detector to achieve good energy resolution and performance.

  15. Total and partial cross sections of the $^{112}$Sn($\\alpha,\\gamma$)$^{116}$Te reaction measured via in-beam $\\gamma$-ray spectroscopy

    CERN Document Server

    Netterdon, L; Scholz, P; Zilges, A

    2015-01-01

    An extended database of experimental data is needed to address uncertainties of the nuclear-physics input parameters for Hauser-Feshbach calculations. Especially $\\alpha$+nucleus optical model potentials at low energies are not well known. The in-beam technique with an array of high-purity germanium (HPGe) detectors was successfully applied to the measurement of absolute cross sections of an ($\\alpha$,$\\gamma$) reaction on a heavy nucleus at sub-Coulomb energies. The total and partial cross-section values were measured by means of in-beam $\\gamma$-ray spectroscopy. Total and partial cross sections were measured at four different $\\alpha$-particle energies from $E_\\alpha = 10.5$ MeV to $E_\\alpha = 12$ MeV. The measured total cross-section values are in excellent agreement with previous results obtained with the activation technique, which proves the validity of the applied method. The experimental data was compared to Hauser-Feshbach calculations using the nuclear reaction code TALYS. A modified version of the...

  16. Positron annihilation spectroscopy applied to silicon-based materials

    CERN Document Server

    Taylor, J W

    2000-01-01

    deposition on silicon substrates has been examined. The systematic correlations observed between the nitrogen content of the films and both the fitted Doppler parameters and the positron diffusion lengths are discussed in detail. Profiling measurements of silicon nitride films deposited on silicon substrates and subsequently implanted with silicon ions at a range of fluences were also performed. For higher implantation doses, damage was seen to extend beyond the film layers and into the silicon substrates. Subsequent annealing of two of the samples was seen to have a significant influence on the nature of the films. Positron annihilation spectroscopy, in conjunction with a variable-energy positron beam, has been employed to probe non-destructively the surface and near-surface regions of a selection of technologically important silicon-based samples. By measuring the Doppler broadening of the 511 keV annihilation lineshape, information on the positrons' microenvironment prior to annihilation may be obtained. T...

  17. Investigation of electric quadrupole interaction in TiO2 by means of perturbed gamma-gamma angular correlation spectroscopy

    International Nuclear Information System (INIS)

    TiO2 has called attention in both basic research and technological applications as an energy converter in solar cells, photo catalyst for water purification, sunscreen material, drug detection, and other applications. In addition TiO2 is a candidate for use in medical devices, food preparation surfaces, air conditioning filters and sanitary ware surfaces.TiO2 has two crystalline phases: anatase and rutile. The structural properties and hyperfine interactions in TiO2 were investigated by perturbed gamma-gamma angular correlation (PAC) spectroscopy using 111 In and 181 Hf as probe nuclei. The PAC spectroscopy provides information on crystalline and electronic structure at an atomic scale. In the present work, PAC measurements on TiO2 were focused on the development of a methodology to prepare bulk samples, which have been characterized by conventional techniques such as x-ray diffraction, (XRD), scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The samples were prepared by the sol gel Pechini method. The resulting powders were annealed at different temperatures in a tubular furnace under nitrogen atmosphere. The PAC measurements were carried out at room temperature in air. The occupation fraction of the probe nuclei reached 50% when the sample was annealed at 1373K and after measured at room temperature.In this case the frequency measured in site 1 is in agreement with that found in literature for substitutional titanium site in rutile structure when 111In were used as probe nuclei. It was measured a frequency more closely to that was found in literature[7] for the case in which 181Hf were used as probe nuclei when the sample annealed at 1373 K and measured at 973 K. (author)

  18. Order statistics and energy-ordered histograms: an exploration into continuum gamma spectroscopy

    International Nuclear Information System (INIS)

    Full text: Let us consider the gamma rays emitted in a fusion-evaporation heavy ion collision. We have different ways to organize and analyze the detected gamma rays: coincidences, angular correlations, DCO, lineshapes, etc. With these methods a wide variety of phenomena mainly in the discrete regime has been investigated. On the opposite, the region of the continuum, though rich in new physics has been by far not as well examined experimentally. The reason for this situation is -in contrast to the discrete spectroscopy- a lack of experimental methods. An approach towards continuum gamma spectroscopy is the so called (H)-(k) technique [1]. Taking advantage of the fact that the gamma rays of an event-by-event detected gamma cascade can be off-line ordered according to their energies, the method of Energy-Ordered Spectra (EOS) was proposed [2] with the goal of picking up the gamma radiation emitted in defined regions of high intrinsic energy and spin. This procedure's success would allow the extension of discrete spectroscopy methods into continuum spectroscopy. Monte Carlo generated EOS show that a judicious comparison between them and experimental ones would allow to study the eventual variation of the level density parameter as a function of intrinsic excitation energy and/or spin [3] ,141. The same work showed that there is even an analytical way to obtain EOS from defined regions of the phase space E - I. The analytical approach comes from the application of the mathematical theory of Order Statistics [5]. This represents a clear improvement to comparisons with numerical simulations: the analytical (fitting) function involves a reduced number of parameters reflect- ing the specific physics under study whereas the large number of input values necessary in a gamma decay simulation does not allow straightforward interpretations. In the present work it is shown that the artificial discontinuities appearing in the previously [3] found fitting function can be avoided

  19. Delayed Gamma-Ray Spectroscopy for Non-Destructive Assay of Nuclear Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ludewigt, Bernhard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mozin, Vladimir [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Campbell, Luke [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Favalli, Andrea [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hunt, Alan W. [Idaho State Univ., Pocatello, ID (United States); Reedy, Edward T. [Idaho State Univ., Pocatello, ID (United States); Seipel, Heather A. [Idaho State Univ., Pocatello, ID (United States)

    2015-06-01

    Modeling capabilities were added to an existing framework and codes were adapted as needed for analyzing experiments and assessing application-specific assay concepts including simulation of measurements over many short irradiation/spectroscopy cycles. The code package was benchmarked against the data collected at the IAC for small targets and assembly-scale data collected at LANL. A study of delayed gamma-ray spectroscopy for nuclear safeguards was performed for a variety of assemblies in the extensive NGSI spent fuel library. The modeling results indicate that delayed gamma-ray responses can be collected from spent fuel assemblies with statistical quality sufficient for analyzing their isotopic composition using a 1011 n/s neutron generator and COTS detector instrumentation.

  20. Environmental radioactivity control by aerial gamma ray spectroscopy: performances and last developments

    International Nuclear Information System (INIS)

    In order to comply with new applications of Aerial Gamma Ray Spectroscopy a quantitative result must be given. The Ray Protection Service of Valduc began mathematical processing studies in order to obtain a better identification of radioelements as well as reduction of detection limits. The elaboration of a calibration methodology corresponding with device characteristics will permit the knowledge of count rate variations lows with experimental parameters and the calculation of gamma radioelements activity. Nevertheless the A.G.R.S characteristics made the interpretation of spectra difficult: distortion of spectra due to interactions of ray with matter, low count rate... Therefore the aim of measures analysis is the obtention of a quick and so exact as possible estimation of nature and activity of gamma radioelements. (authors). 15 figs., 1 ref

  1. A new FSA approach for in situ $\\gamma$-ray spectroscopy

    CERN Document Server

    Caciolli, A; Bezzon, G P; Broggini, C; Buso, G P; Callegari, I; Colonna, T; Fiorentini, G; Guastaldi, E; Mantovani, F; Massa, G; Menegazzo, R; Mou, L; Alvarez, C Rossi; Shyti, M; Zanon, A; Xhixha, G

    2011-01-01

    An increasing demand of environmental radioactivity monitoring comes both from the scientific community and from the society. This requires accurate, reliable and fast response preferably from portable radiation detectors. Thanks to recent improvements in the technology, $\\gamma$-spectroscopy with sodium iodide scintillators has been proved to be an excellent tool for in-situ measurements for the identification and quantitative determination of $\\gamma$-ray emitting radioisotopes, reducing time and costs. Both for geological and civil purposes not only $^{40}$K, $^{238}$U, and $^{232}$Th have to be measured, but there is also a growing interest to determine the abundances of anthropic elements, like $^{137}$Cs and $^{131}$I, which are used to monitor the effect of nuclear accidents or other human activities. The Full Spectrum Analysis (FSA) approach has been chosen to analyze the $\\gamma$-spectra. The Non Negative Least Square (NNLS) and the energy calibration adjustment have been implemented in this method f...

  2. Diffusing wave spectroscopy applied to material analysis and process control

    International Nuclear Information System (INIS)

    Diffusing Wave Spectroscopy (DWS) was studied as a method of laboratory analysis of sub-micron particles, and developed as a prospective in-line, industrial, process control sensor, capable of near real-time feedback. No sample pre-treatment was required and measurement was via a non-invasive, flexible, dip in probe. DWS relies on the concept of the diffusive migration of light, as opposed to the ballistic scatter model used in conventional dynamic light scattering. The specific requirements of the optoelectronic hardware, data analysis methods and light scattering model were studied experimentally and, where practical, theoretically resulting in a novel technique of analysis of particle suspensions and emulsions of volume fractions between 0.01 and 0.4. Operation at high concentrations made the technique oblivious to dust and contamination. A pure homodyne (autodyne) experimental arrangement described was resilient to environmental disturbances, unlike many other systems which utilise optical fibres or heterodyne operation. Pilot and subsequent prototype development led to a highly accurate method of size ranking, suitable for analysis of a wide range of suspensions and emulsions. The technique was shown to operate on real industrial samples with statistical variance as low as 0.3% with minimal software processing. Whilst the application studied was the analysis of TiO2 suspensions, a diverse range of materials including polystyrene beads, cell pastes and industrial cutting fluid emulsions were tested. Results suggest that, whilst all sizing should be comparative to suitable standards, concentration effects may be minimised and even completely modelled-out in many applications. Adhesion to the optical probe was initially a significant problem but was minimised after the evaluation and use of suitable non stick coating materials. Unexpected behaviour in the correlation in the region of short decay times led to consideration of the effects of rotational diffusion

  3. Monitoring of the interconversion of gamma-butyrolactone (GBL) to gamma hydroxybutyric acid (GHB) by Raman spectroscopy.

    Science.gov (United States)

    Munshi, Tasnim; Brewster, Victoria L; Edwards, Howell G M; Hargreaves, Michael D; Jilani, Shelina K; Scowen, Ian J

    2013-08-01

    Gamma-hydroxybutyric acid (GHB) is a drug-of-abuse that has recently become associated with drug-facilitated sexual assault, known as date rape. For this reason the drug is commonly found 'spiked' in alcoholic beverages. When GHB is in solution it may undergo conversion into the corresponding lactone, Gamma-butyrolactone (GBL). Studies have been carried out to determine the detection limits of GHB and GBL in various solutions by Raman spectroscopy and to monitor the interconversion of GHB and GBL in solution with different pH conditions and temperature. In this study, a portable Raman spectrometer was used to study the interconversion of GHB and GBL in water and ethanol solutions as a function of pH, time, and temperature. The aim of this was to determine the optimum pH range for conversion in order to relate this to the pH ranges that the drug is likely to be subjected to, first in spiked beverages and secondly after ingestion in the digestive system. The aim was also to identify a timescale for this conversion in relation to possible scenarios, for example if GHB takes a number of hours to convert to GBL, it is likely for the beverage to be ingested before esterification can take place. GHB and GBL were then spiked into a selection of beverages of known pH in order to study the stability of GHB and GBL in real systems. PMID:23225646

  4. Possibility of applying the gamma-gamma method to the in situ determination of uranium-ore densities

    International Nuclear Information System (INIS)

    The principles of the gamma-gamma method are reviewed. It is shown in particular that, under certain conditions, the method makes it possible to obtain a representative measurement of the electronic density. Chemical analyses have been carried out on samples obtained from uranium deposits. The results show that an exact correlation exists between the massive and electronic densities. It is possible to consider the possibility of measuring the density of uranium-containing rocks by the gamma-gamma method. (authors)

  5. Some results of Auger spectroscopy and emission spectroscopy applied to impregnated cathodes

    International Nuclear Information System (INIS)

    A study of impregnated cathodes using combined Auger spectroscopy and emission microscopy shows that a realistic pressures regions of thick-film coverage emit more strongly than monolayer regions. The presence of sulphur and phosphorus on the surface of dispenser cathodes has been correlated with poor emission. These contaminants may be removed by heating cathodes in oxygen, a process which increases substantially the emission available from poor cathodes. (orig.)

  6. Possibilities for applying gamma-spectrometry software ANGLE in isotope hydrology analytical procedures

    International Nuclear Information System (INIS)

    ANGLE software for gamma-spectrometry (semiconductor detector gamma-efficiency calculations, in particular) in its various forms has been in use for 15 years in numerous gamma-spectrometry laboratories all around. ANGLE is basically a semi-empirical model for efficiency calculations, which combines the advantages of both absolute and relative approach, while attempting to minimize their drawbacks. The physical model behind is the concept of the effective solid angle, which is calculated upon the input data on the geometrical and physical characteristics of (1) the source (including the container vessel), (2) the detector and (3) the counting arrangement (including intercepting layers between the latter two). It was shown earlier that only the simultaneous differential treatment of gamma-attenuation, geometry and detector response, as in ANGLE, is essentially justified for this type of calculations. The program can be applied to practically all counting situations encountered in laboratory practice: point, disc, cylindrical or Marinelli sources and any matrix composition. No standards are required, but a so called 'reference efficiency curve' should be obtained ('once for ever') by measuring a set of calibrated point sources. As a summary, ANGLE is characterized by (1) a very broad application range, (2) satisfactory accuracy (of the order of a few percent), (3) easy data manipulation (under WINDOWS), (4) short computation times, (5) flexibility in respect with input parameters and (6) suitability for didactical purposes. Possibilities for applying ANGLE in isotope hydrology analytical procedures (e.g. with radioactive tracers involved), are discussed. Tracer techniques are of particular interest for water resources management in Mediterranean karstic regions, typically abundant with precipitation in winter, but scarce with ground waters in summer - like is the case with east coast of Adriatic, including the coastal part of Montenegro. (author)

  7. Determination of nuclear fuel burnup by non-destructive gamma spectroscopy

    International Nuclear Information System (INIS)

    The determination of nuclear fuel burnup by the non-destructive gamma spectroscopy method is studied. A MTR (Materials Testing Reactor) -type fuel element is used in the measurement. The fuel element was removed from the reactor core in 1958 and, because of the long decay time, show only one peak in is gamma spectrum at 661.6 Kev. Corresponding to 137Cs. Measurements are made at 330 points of the element using a Nal detector and the final result revealed that the quantity of 235U consumed was 3.3 +- 0,8 milligram in the entire element. The effect of the migration of 137Cs in the element is neglected in view of the fact that it occurs only when the temperature is above 10000C, which is not the case in IEAR-1. (Author)

  8. Perspectives for neutron and gamma spectroscopy in high power laser driven experiments at ELI-NP

    Science.gov (United States)

    Negoita, F.; Gugiu, M.; Petrascu, H.; Petrone, C.; Pietreanu, D.; Fuchs, J.; Chen, S.; Higginson, D.; Vassura, L.; Hannachi, F.; Tarisien, M.; Versteegen, M.; Antici, P.; Balabanski, D.; Balascuta, S.; Cernaianu, M.; Dancus, I.; Gales, S.; Neagu, L.; Petcu, C.; Risca, M.; Toma, M.; Turcu, E.; Ursescu, D.

    2015-02-01

    The measurement of energy spectra of neutrons and gamma rays emitted by nuclei, together with charge particles spectroscopy, are the main tools for understanding nuclear phenomena occurring also in high power laser driven experiments. However, the large number of particles emitted in a very short time, in particular the strong X-rays flash produced in laser-target interaction, impose adaptation of technique currently used in nuclear physics experiment at accelerator based facilities. These aspects are discussed (Section 1) in the context of proposed studies at high power laser system of ELI-NP. Preliminary results from two experiments performed at Titan (LLNL) and ELFIE (LULI) facilities using plastic scintillators for neutron detection (Section 2) and LaBr3(Ce) scintillators for gamma detection (Section 3) are presented demonstrating the capabilities and the limitations of the employed methods. Possible improvements of these spectroscopic methods and their proposed implementation at ELI-NP will be discussed as well in the last section.

  9. Comparison of in situ and laboratory gamma spectroscopy of natural radionuclides in desert soil.

    Science.gov (United States)

    Benke, R R; Kearfott, K J

    1997-08-01

    In situ and laboratory gamma spectroscopy were used to characterize natural background levels of radiation in the soil at eight sites around the Yucca Mountain Range. The purpose of this practical field analysis was to determine if published empirical in situ calibration factors would yield accurate quantitative specific activities (Bq kg(-1)) in a desert environment. Corrections were made to the in situ calibration factors to account for the on-axis response of a detector with a thin beryllium end window. The in situ gamma spectroscopy results were compared to laboratory gamma spectroscopy of soil samples gathered from each site. Five natural radionuclides were considered: 40K, 214Pb, 214Bi, 208Tl, and 228Ac. The in situ determined specific activities were consistently within +/-15% of the laboratory soil sample results. A quantitative discussion of the factors contributing to the uncertainty in the in situ and laboratory results is included. Analysis on the specific activity data using statistical hypothesis tests determined that three nuclides, 214Pb, 214Bi, and 228Ac showed a weak site dependence while the other two nuclides, 40K and 208Tl, did not exhibit a site dependence. Differing radiation background levels from site to site along with in situ and laboratory uncertainties in excess of 10% are two factors that account for the weak site dependence. Despite the good correlation between data, it was recommended that the in situ detector be calibrated by a detector-specific Monte Carlo code which would accurately model more complex geometries and source distributions. PMID:9228170

  10. Study of radioactivity levels in detergent powders samples by gamma spectroscopy

    OpenAIRE

    Ali A. Abojassim; Hussain H. Abd; Dalal N. Hamed; Anmar A. Abdullah

    2014-01-01

    This study focuses on the evaluation of the natural radioactivity levels in ten samples of the detergent powders that available in Iraqi markets. We have determined the specific activities of uranium, thorium and potassium using gamma spectroscopy and calculation of radiation hazard indices. The results of the activities of radionuclides (238U, 232Th, 40K) for detergent powders samples, are found that the 238U specific activities were varied from (11.489 ± 2.089) Bq/kg to (36.062 ± 2.478) Bq/...

  11. Gamma-ray-spectroscopy following high-flux 14-MeV neutron activation

    International Nuclear Information System (INIS)

    The Rotating Target Neutron Source (RTNS-I), a high-intensity source of 14-MeV neutrons at the Lawrence Livermore National Laboratory (LLNL), has been used for applications in activation analysis, inertial-confinement-fusion diagnostic development, and fission decay-heat studies. The fast-neutron flux from the RTNS-I is at least 50 times the maximum fluxes available from typical neutron generators, making these applications possible. Facilities and procedures necessary for gamma-ray spectroscopy of samples irradiated at the RTNS-I were developed

  12. A Monte Carlo approach to food density corrections in gamma spectroscopy

    International Nuclear Information System (INIS)

    Evaluation of food products by gamma spectroscopy requires a correction for food density for many counting geometries and isotopes. An inexpensive method to develop these corrections has been developed by creating a detailed model of the HPGe crystal and counting geometry for the Monte Carlo transport code MCNP. The Monte Carlo code was then used to generate a series of efficiency curves for a wide range of sample densities. The method was validated by comparing the MCNP generated efficiency curves against those obtained from measurements of NIST traceable standards, and spiked food samples across a range of food densities. (author)

  13. Heavy ion deep inelastic collisions studied by discrete gamma ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Krolas, W. [The H. Niewodniczanski Inst. of Nuclear Physics, Cracow (Poland)

    1996-05-01

    The discrete gamma ray spectroscopy has been used as a tool to investigate the heavy ion collision. It has been shown that such experimental information supplemented by results of additional of-line radioactivity measurements is complete enough to reconstruct distributions of products of very complex nuclear reactions. Three experiments have been performed in which the {sup 208}Pb + {sup 64}Ni, {sup 130}Te + {sup 64}Ni and {sup 208}Pb + {sup 58}Ni systems have been created. The production cross sections of fragment isotopes have been determined and compared with existing model predictions 64 refs, 59 figs, 19 tabs

  14. Simulation and Characterization of Single Photon Detectors for Fluorescence Lifetime Spectroscopy and Gamma-ray Applications

    OpenAIRE

    Benetti, Michele

    2012-01-01

    Gamma-ray and Fluorescence Lifetime Spectroscopies are driving the development of non-imaging silicon photon sensors and, in this context, Silicon Photo-Multipliers (SiPM)s are leading the starring role. They are 2D array of optical diodes called Single Photon Avalanche Diodes (SPAD)s, and are normally fabricated with a dedicated silicon process. SPADs amplify the charge produced by the single absorbed photon in a way that recalls the avalanche amplification exploited in Photo-Multiplier Tube...

  15. Quantification by Raman spectroscopy of the gamma radiation effects in water purification

    International Nuclear Information System (INIS)

    The world problem about water pollution has been confronted by traditional methods such as: chlorination, filtration, etc. In this work is presented an alternative method, which consists in to radiate different concentrations of simulated polluted water (purified water + thinner) at different gamma radiation doses. The structural changes were analysed by Raman spectroscopy. Using a 52.5 Krad dose it was possible to eliminate all the thinner chemical linkages, which appear in the Raman spectra corresponding to the 87.5/12.5 water/thinner mixture. (Author)

  16. Gamma-ray-spectroscopy following high-flux 14-MeV neutron activation

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R.E.

    1981-10-12

    The Rotating Target Neutron Source (RTNS-I), a high-intensity source of 14-MeV neutrons at the Lawrence Livermore National Laboratory (LLNL), has been used for applications in activation analysis, inertial-confinement-fusion diagnostic development, and fission decay-heat studies. The fast-neutron flux from the RTNS-I is at least 50 times the maximum fluxes available from typical neutron generators, making these applications possible. Facilities and procedures necessary for gamma-ray spectroscopy of samples irradiated at the RTNS-I were developed.

  17. Detection of gamma-irradiated peanuts by ESR spectroscopy and GC analysis of hydrocarbons

    International Nuclear Information System (INIS)

    Peanuts were analyzed by electron spin resonance (ESR) spectroscopy and gas chromatography (GC) before and after gamma irradiation. Using European protocols, the validity and effectiveness of these two techniques were compared with regard to sample preparation, sample and solvent consumption and dose-response curves after irradiation. The results showed the possibility of using ESR and GC for distinguishing between irradiated and unirradiated peanuts. A radiation dose of 0.1 kGy could be detected by ESR but not by GC. The results also indicated that GC is an effective method for qualitative analysis of irradiated peanut, while ESR is suitable for the rapid detection of irradiated peanuts.

  18. Interaction between gamma radiation and toxicity of three insecticides applied to the blowfly Lucilia Cuprina

    International Nuclear Information System (INIS)

    Effect of gamma-radiation on the toxicity of D.D.T., Lindane and Dieldrin was studied using females of the blowfly Lucilia cuprina Wied. Variable doses of insecticides were applied on the 3-day old adult blowflies which emerged from irradiated pupae. The radiation doses were given 48 hours before emergence. The results indicated that pupal irradiation slightly increased the susceptibility of insects to the insecticides and in case of Dieldrin LD50 was reached quicker than other two compounds. It is suggested that the alteration in response may be due to an internal stimulus due to radiation which cannot be solely attributed to the loss of detoxification mechanism. (author)

  19. The transient gamma-ray spectrometer: A new high resolution detector for gamma-ray burst spectroscopy

    International Nuclear Information System (INIS)

    The Transient Gamma-Ray Spectrometer (TGRS) to be flown aboard the WIND spacecraft is primarily designed to perform high resolution spectroscopy of transient gamma-ray events, such as cosmic γ-ray bursts and solar flares, over the energy range 20 keV to 10 MeV with an expected spectroscopic resolution of E/δE = 500. The detector itself consists of a 215 cm3 high purity n-type Ge crystal kept at cryogenic temperatures by a passive radiative cooler. The geometric field of view defined by the cooler is 170 degrees. To avoid continuous triggers caused by soft solar events, a thin Be/Cu sun-shield around the sides of the cooler has been provided. A passive Mo/Pb occulter, which modulates signals from within ±5 degrees of the ecliptic plane at the spacecraft spin frequency, is used to identify and study solar flares, as well as emission from the galactic plane and center. Thus, in addition to transient event measurements, the instrument will allow the search for possible diffuse background lines and monitor the 511 keV positron annihilation radiation from the galactic center. In order to handle the typically large burst count rates which can be in excess of 100 kHz, burst data are stored directly in an on-board 2.75 Mbit burst memory with an absolute timing accuracy of ±1.5 ms after ground processing. This capacity is sufficient to store the entire spectral data set of all but the largest bursts. The experiment is scheduled to be launched on a Delta II launch vehicle from Cape Canaveral in the fall of 1993

  20. FY12 Final Report for PL10-Mod Separations-PD12: Electrochemically Modulated Separation of Plutonium from Dilute and Concentrated Dissolver Solutions for Analysis by Gamma Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, Sandra H.; Arrigo, Leah M.; Duckworth, Douglas C.; Cloutier, Janet M.; Breshears, Andrew T.; Schwantes, Jon M.

    2013-05-01

    Accurate and timely analysis of plutonium in spent nuclear fuel is critical in nuclear safeguards for detection of both protracted and rapid plutonium diversions. Gamma spectroscopy is a viable method for accurate and timely measurements of plutonium provided that the plutonium is well separated from the interfering fission and activation products present in spent nuclear fuel. Electrochemically modulated separation (EMS) is a method that has been used successfully to isolate picogram amounts of Pu from nitric acid matrices. With EMS, Pu adsorption may be turned “on” and “off” depending on the applied voltage, allowing for collection and stripping of Pu without the addition of chemical reagents. In this work, we have scaled up the EMS process to isolate microgram quantities of Pu from matrices encountered in spent nuclear fuel during reprocessing. Several challenges have been addressed including surface area limitations, radiolysis effects, electrochemical cell performance stability, and chemical interferences. After these challenges were resolved, 6 µg Pu was deposited in the electrochemical cell with approximately an 800-fold reduction of fission and activation product levels from a spent nuclear fuel sample. Modeling showed that these levels of Pu collection and interference reduction may not be sufficient for Pu detection by gamma spectroscopy. The main remaining challenges are to achieve a more complete Pu isolation and to deposit larger quantities of Pu for successful gamma analysis of Pu. If gamma analyses of Pu are successful, EMS will allow for accurate and timely on-site analysis for enhanced Pu safeguards.

  1. Use of in-situ gamma spectroscopy during nuclear power plant decommissioning - 59340

    International Nuclear Information System (INIS)

    Document available in abstract form only. Full text of publication follows: The Electric Power Research Institute (EPRI) is a non-profit research organization that supports the energy industry. The Nuclear Power Plant Decommissioning Technology Program conducts research and develops technology for the safe and efficient decommissioning of nuclear power plants. One of the key objectives of the EPRI Decommissioning Technology Program is to capture the good practices and lessons learned from plants currently undergoing decommissioning. Several major plant decommissioning programs have been successfully completed, so EPRI is documenting relevant experiences to aid future decommissioning activities, both in the United States and internationally. In-situ Gamma Spectroscopy is powerful technology with the potential for widespread application in nuclear power plant radiological surveys. Due to leakage and other events that may occur during nuclear power plant operations, soil, concrete and bedrock have the potential to become contaminated, and therefore must be characterized to demonstrate that they meet strict regulatory site release limits. The radiological surveys conducted during power plant decommissioning have historically been very labor intensive, time consuming and often extend decommissioning duration. The use of hand-held survey meters was typical during early decommissioning. As engineers gained experience, they often replaced the hand-held meters with advanced technologies such as the In-situ Gamma Spectroscopy instruments

  2. Gamma ray spectroscopy at high energy and high time resolution at JET.

    Science.gov (United States)

    Tardocchi, M; Proverbio, L I; Gorini, G; Grosso, G; Locatelli, M; Chugonov, I N; Gin, D B; Shevelev, A E; Murari, A; Kiptily, V G; Syme, B; Fernandes, A M; Pereira, R C; Sousa, J

    2008-10-01

    In fusion plasmas gamma ray emission is caused by reactions of fast particles, such as fusion alpha particles, with impurities. Gamma ray spectroscopy at JET has provided valuable diagnostic information on fast fuel as well as fusion product ions. Improvements of these measurements are needed to fully exploit the flux increase provided by future high power experiments at JET and ITER. Limiting aspects are, for instance, the count rate capability due to a high neutron/gamma background combined with slow detector response and a modest energy resolution due to the low light yield of the scintillators. This paper describes the solutions developed for achieving higher energy resolution, signal to background, and time resolution. The detector design is described based on the new BrLa3 scintillator crystal. The paper will focus on hardware development, including a photomultiplier tube capable of stable operation at counting rate as high as 1 MHz, the magnetic shielding, and the fast digital data acquisition system. PMID:19068513

  3. Use of Field High Resolution Gamma Spectroscopy during Decontamination and Decommissioning of Nuclear Facilities

    International Nuclear Information System (INIS)

    This paper describes the utilization and evolution of field high-resolution gamma spectroscopy (field-HRGS) during decontamination and decommissioning (D and D) of a nuclear facility; beginning with characterization of drummed and boxed radioactive waste for purpose of shipment and disposal, and ending with survey and analysis of radioactive material held-up in building fixtures and structures leading to improvements in radiation safety, environmental protection, waste disposal, and regulatory compliance. This technology also provides detailed documentation of regulatory compliant clean-up and disposal activities. Compared to other radiation detection technologies, HRGS provides the best gamma radionuclide identification capabilities for both naturally occurring radionuclides such as U-238, U-235, U-234, Th-232, Th-228, Ra-226 and their daughter products as well as other radionuclides (Pu-239, Am-241, Ba-133, Cs-137, Co-60, etc.) associated with human activities. No other technique can match the ability to quantify gamma radionuclides on an activity, mass, and concentration basis in the field as well as HRGS. HRGS is a powerful analytical tool often overlooked by industry in favor of other less costly and less complicated measurement techniques such as sodium iodide (NaI) or cadmium zinc telluride (CZT) survey. When used properly - in a coordinated effort during D and D operations, field-HRGS survey and analysis can provide large benefits in radiation and environmental protection, waste reduction, waste disposal, and regulatory compliance with anticipated lowering of risk and overall savings in cost. (authors)

  4. Experimental investigation of silicon photomultipliers as compact light readout systems for gamma-ray spectroscopy applications in fusion plasmas

    International Nuclear Information System (INIS)

    A matrix of Silicon Photo Multipliers has been developed for light readout from a large area 1 in. × 1 in. LaBr3 crystal. The system has been characterized in the laboratory and its performance compared to that of a conventional photo multiplier tube. A pulse duration of 100 ns was achieved, which opens up to spectroscopy applications at high counting rates. The energy resolution measured using radioactive sources extrapolates to 3%–4% in the energy range Eγ = 3–5 MeV, enabling gamma-ray spectroscopy measurements at good energy resolution. The results reported here are of relevance in view of the development of compact gamma-ray detectors with spectroscopy capabilities, such as an enhanced gamma-ray camera for high power fusion plasmas, where the use of photomultiplier is impeded by space limitation and sensitivity to magnetic fields

  5. Feasibility Study on Fiber-optic Radiation Sensor for Remote Gamma-ray Spectroscopy

    International Nuclear Information System (INIS)

    In this study, we fabricated a fiber-optic radiation sensor using an optical fiber and various scintillators. To select an adequate inorganic scintillator for the sensing probe of fiber-optic radiation sensor, 5 types of scintillators were evaluated. The spectra of gamma-rays emitted from a Na-22 radiation source were measured by using the manufactured sensors. As a result, the BGO was suitable for the sensing probe of fiber-optic radiation sensor due to its high scintillation output and exact photoelectric peak for the gamma-ray energy. The basic principle of radiation detection is to detect the signals caused by interactions between radiations and materials. There are various types of radiation detectors depending on types of radiation to be detected and physical quantities to be measured. As one of the radiation detectors, a fiber-optic radiation sensor using a scintillator and an optical fiber has two advantages such as no space restraint and remote sensing. Moreover, in nuclear environments, this kind of sensor has immunities for electromagnetic field, temperature, and pressure. Thus, the fiber-optic radiation sensor can be used in various fields including nondestructive inspection, radioactive waste management, nuclear safety, radiodiagnosis and radiation therapy. As a fundamental study of the fiber-optic radiation sensor for remote gamma-ray spectroscopy, in this study, we fabricated a fiber-optic radiation sensor using an optical fiber and various scintillators. To select an adequate inorganic scintillator for the sensing probe of fiber-optic radiation sensor, 5 types of scintillators were evaluated. The spectra of gamma-rays emitted from a Na-22 radiation source were measured by using the manufactured sensors

  6. Multigroup Albedo Method applied to coupled neutron-gamma radiations shielding

    International Nuclear Information System (INIS)

    Shielding calculations for neutron-gamma radiation are usually done by using the full Theory of Transport or the Monte Carlo Techniques. After some works based on the Albedo Method, the shielding calculations for neutron-gamma radiation have a reliable tool with great didactical value which shows its clarity and simplicity for the resolution of cases that involve neutrons and photon shielding in nonmultiplying media. The excellent results of these works have motivated the elaboration and the development of this study that will be presented in this dissertation. The balance of a neutronic current entering a shield of two layers considering the coupling neutron-gamma will be determined by the Albedo Method. The shield will be composed of a layer of iron and another one of manganese with 10 cm of thickness each. The arrays of the materials coefficients will be obtained from the ANISN code. ANISN is a one dimensional deterministic code that is based on transport equation. The final results obtained by the Albedo Method will be compared with the ANISN results for an order of angular quadrature S2. The angular quadrature S2 admits that the radiation has two routes in the same direction what better describes the Albedo Method behavior. The results obtained by using the Albedo Method show an excellent agreement with the values predicted by the adopted deterministic code ANISN. Due to the excellent results, the multigroup Albedo Method should be applied to the shielding calculations with multiple layers. In conclusion the multigroup Albedo Method has the great ability in solving shielding problems concerning to the Nuclear Engineering. (author)

  7. Isotopic ratios and effective power determined by gamma-ray spectroscopy vs mass spectroscopy for molten salt extraction residues

    International Nuclear Information System (INIS)

    Impure plutonium metal is routinely processed by molten salt extraction (MSE) to reduce the amount of americium in the metal product. Throughput at various facilities where similar processes are performed has made it essential to evaluate uncertainties and possible discrepancies in the analyses of these difficult MSE materials. In an effort to evaluate the plutonium isotopic ratios and americium concentrations obtained from gamma-ray spectral data analyzed by the computer code GRPAUT, measurements were made on ten MSE salts as received and after pulverization and blending. These results were then compared to the specific powers obtained from isotopic ratios determined by mass spectrometry on these same ten samples. Americium values ranged from a few thousand parts-per-million of total plutonium to greater than 50,000 ppM. Our results indicate a small discrepancy between specific powers as determined by GRPAUT on ''as received'' vs pulverized and blended MSE salts. The specific powers obtained via GRPAUT on the pulverized salts agree somewhat better with specific powers obtained from the mass spectroscopy data. This work may indicate that a small discrepancy exists in the specific powers by using GRPAUT on heterogeneous, high americium samples. 5 refs., 6 tabs

  8. Gamma large area silicon telescope: Applying SI strip detector technology to the detection of gamma rays in space

    Science.gov (United States)

    Atwood, W. B.; Bloom, E. D.; Godfrey, G. L.; Hertz, P. L.; Lin, Ying-Chi; Nolan, P. L.; Snyder, A. E.; Taylor, R. E.; Wood, K. S.; Michelson, P. F.

    1992-12-01

    The recent discoveries and excitement generated by EGRET (Energetic Gamma Ray Experiment Telescope) (presently operating on CGRO (Compton Gamma Ray Observatory)) has prompted an investigation into modern technologies ultimately leading to the next generation space based gamma ray telescope. The goal is to design a detector that would increase the data acquisition rate by almost two orders of magnitude beyond EGRET, while at the same time improving on the angular resolution, the energy measurement of reconstructed gamma rays and the triggering capability of the instrument. The proposed GLAST (Gamma Ray Large Area Silicon Telescope) instrument is based on silicon particle detectors that offer the advantages of no consumables, no gas volume, robust (versus fragile), long lived, and self triggering. The GLAST detector is roughly modeled after EGRET in that a tracking module precedes a calorimeter. The GLAST tracker has planes of cross strip (x, y) 300 micrometer match silicon detectors coupled to a thin radiator to measure the coordinates of converted electron-positron pairs. An angular resolution of 0.1 deg at high energy is possible (the low energy angular resolution 100 MeV would be about 2 deg, limited by multiple scattering). The increased depth of the GLAST calorimeter over EGRET's extends the energy range to about 300 GeV.

  9. 1H MR spectroscopy of mesial temporal lobe epilepsies treated with Gamma knife

    International Nuclear Information System (INIS)

    Proton MR spectroscopy was used to observe long-term post-irradiation metabolic changes in epileptogenic tissue and in the contralateral parts of the brain which are not available with conventional imaging methods. We studied these changes in the temporal lobe in six patients, following radiosurgery on the amygdala and hippocampus. 1H MR spectroscopy at 1.5 T with short and long echo times (TE=10 and 135 ms) were used together with standard MR imaging sequences (T1-, T2-weighted). The treatment was performed by Leksell Gamma Knife with a dose of 50 Gy to the center and a 50% isodose to the margin of the target, represented by the mean volume of approximately 7.5 ml. Magnetic resonance imaging and MR spectroscopy examinations were performed at least once per year for 3 years. The most significant changes in spectra were observed approximately 1 year after the irradiation when edema in irradiated area was observed and strong signal of lipids was identified. Later, edema and lipid signals disappeared and follow-up was characterized by a decrease of NAA, Cr, and Cho concentrations in the ipsilateral region of the brain to the irradiation (LCModel calculation from voxel of interest 3.8-4.5 ml positioned into the centrum of target volume). The concentration of NAA, Cr, and Cho after radiosurgery was significantly different from control values (p<0.05) and also from concentrations in the contralateral part of the brain (p<0.05). In the contralateral part, the concentration of NAA was significantly increased (p<0.05) (NAA: before treatment 8.81, after treatment 11.33 mM). No radiotoxic changes were observed in the contralateral part of the brain or behind the area of target volume. The MR spectroscopy findings precluded MRI observation and MRS results completed data about the development of radiotoxic changes in the target volume. (orig.)

  10. Dosimetry of electron and gamma radiation with alanine/ESR spectroscopy

    International Nuclear Information System (INIS)

    A new method for the preparation of alanine dosimeters was investigated. The absorbed dose response of these dosimeters was demonstrated for 10 MeV electron and 60Co gamma radiation in the range from 20 Gy to 1.1 kGy. Concentration of the irradiation-induced free radicals in the alanine was determined by ESR spectroscopy. In addition to measurements at ambient temperature, the alanine dosimeters were also subjected to thermal treatment during irradiation (up to about 50 deg. C) in order to assess their performance characteristics under extreme conditions which might arise in future technical applications. The results show that under normal conditions the alanine calibration curves are linear, whereas at higher temperatures the dosimeters require a correction of 0.3%/K for absorbed doses above 200 Gy. (author)

  11. Study of spin-temperature effects using energy-ordered continuum gamma-ray spectroscopy technique

    International Nuclear Information System (INIS)

    We have investigated a new continuum γ-ray spectroscopy technique which is based on the detection of all emitted γ rays in a 4π detector system, and ordering them according to their energies on an event-by-event basis. The technique allows determination of gamma strength functions, and rotational damping width as a function of spin and temperature. Thus, it opens up the possibility of studying the onset of motional narrowing, order-to-chaos transition, and the mapping of the evolution of nuclear collectivity with a spin and temperature. Application of the technique for preferential entry-state population, exit-channel selection, and feeding of the discrete states via selective pathways will be discussed. 20 refs., 4 figs

  12. Towards the definition of the optimum height of voluminous cylindrical sources in gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    We show that for cylindrical voluminous sources in gamma-ray spectroscopy the relative error of the spectral intensity of a low-energy spectral line, as the height of the source increases, saturates faster than the spectral intensity itself. This significantly reduces the quantity of the required sample material as compared to that based on the usual considerations of the spectral intensity only. We also demonstrate that there exists a weakly pronounced height of the source (the source size) which minimizes the relative error of the intensity of a given low-energy spectral line. Due to the smallness of the effect the benefit of introducing the concept of the truly optimum size of the source is more on a psychological side, one should feel easier using an optimum quantity of the source material than merely a sufficient one, as is otherwise the case

  13. Experimental study of the burned of nuclear fuel by the gamma spectroscopy method

    International Nuclear Information System (INIS)

    Accurate information on nuclear fuel burnup is of vital importance in reactor operation, fuel management and fuel-characteristics studies. Conventionally fuel management of the TRIGA III Reactor from the National Institute of Nuclear Research (ININ) is done through the thermal balance method (management) of the power generated during reactor operation, since it is known that with 1.24 grams of 235U is possible to generate a power or 1 MW per day during the reactor operation. On the other hand, it is possible to calculate the operation time in days during a power of 1 MW with the help of the data registered in logs. With the information just mentioned one can calculate the quantity of 235U consumed in the fuel during a complete period of irradiation. In order to compare and prove that the burnup values, calculated through the thermal balance method, are correct, the ININ implemented, for the first time, the gamma-ray spectroscopy method as an experimental technique to calculate the burnup of several fuel elements. Gamma-ray spectroscopy is a nondestructive method, so that the integrity of the fuel element is not affected which is of great importance. Since there is a direct relation between the activity of 137Cs contained in the fuel elements and a series of constants which are unique for the radioisotope and for the high resolution system, the problem just simplifies in measuring the 137Cs activities. Furthermore the 137Cs concentration equation was developed theoretically and I wrote a computer program (AMAVAL) in Fortran. The task of this program is to calculate the concentrations and the activity through the use of the equation just mentioned and the history of each fuel element. The purpose of this is to compare and validate the experimental activities with the theoretical ones for each fuel element. (Author)

  14. The recent developments in the technology of scintillator detectors for gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    The goal of this report is to review the recent developments in the use of high stopping power materials and solid state readout for scintillation gamma -ray spectroscopy as these techniques may give rise to a new generation of low powered portable instruments. The report is a bibliographical study based on papers published mainly these last five years. The main subject is preceded by a general introduction in which the principal characteristics of a scintillator gamma-ray spectrometer are discussed. The properties of some scintillator materials (NaI(T1), CsI(T1), CsI(Na), BGO, GSO(Ce) and CdWO4) are then briefly presented. In this section, a special emphasis has been given to BGO as this material has recently received much attention and is now well documented. Finally, the results obtained by measuring the intensity of the light generated in the crystal with three types of solid-state photodetectors (Si photodiodes, HgI2 photodetectors and avalanche Si photodiodes) are summarized

  15. Gamma-ray spectroscopy using CsI and silicon Pine photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Taehoon; Jeong, Sungyeop; Kwon, Soocheon [Sungwoo E and T, Seoul (Korea, Republic of)

    2010-07-01

    The Finger generally uses two detector modules which are parallel for each other. They are all scintillator coupled photodiode detectors and the thickness of coupled photodiode detectors and the thickness of each scintillator is designed to absorb about 80% of radiations entering the scintillator. In order to acquire more detail information and reduce the error of measuring the ratio, the sensitivity of each detector should be improved. In this study, we proposed a new idea to increase the sensitivity of each detector by using two parallel detector modules for gamma-ray radiography. The aim of this work was to evaluate the ability of the new detector to improve the signal to noise ration, and to establish the methodology for counting in the new detector module with coincidence spectroscopy circuit. For this purpose, we optimized the scintillator thickness for {sup 60}Co by the Monte Carlo simulation code and the characteristics of operation and noise tests were accomplished after Scintillator coupling. We fabricated the Pine photodiode coupled with crystal for the Finger. We performed experiments and analyzed the results concentrating on the characteristics of signal and noise with Pine photodiode and CSR to detect high energy gamma and dominant factors to minimize system noise were capacitance than dark current of photodiode. As a result of measurement using the two parallel detector modules in this study, the sensitivity was considerably improved. We proved that our detector system is reliable for Finger.

  16. Perspectives for neutron and gamma spectroscopy in high power laser driven experiments at ELI-NP

    Energy Technology Data Exchange (ETDEWEB)

    Negoita, F., E-mail: negoita@nipne.ro; Gugiu, M., E-mail: negoita@nipne.ro; Petrascu, H., E-mail: negoita@nipne.ro; Petrone, C., E-mail: negoita@nipne.ro; Pietreanu, D., E-mail: negoita@nipne.ro [IFIN-HH, Str. Reactorului nr. 30, 077125 Bucharest-Magurele (Romania); Fuchs, J.; Chen, S.; Higginson, D.; Vassura, L. [LULI, UMR 7605 CNRS-CEA-EcolePolytechnique-Universite Paris VI, 91128 Palaiseau (France); Hannachi, F.; Tarisien, M.; Versteegen, M. [Universite Bordeaux 1, CENBG, CNRS-IN2P3, Route du solarium, 33175 Gradignan (France); Antici, P. [LULI, UMR 7605 CNRS-CEA-EcolePolytechnique-Universite Paris VI, 91128 Palaiseau, France and Univ. Roma La Sapienza, Dipartimento SBAI, 00165 Rome (Italy); Balabanski, D.; Balascuta, S.; Cernaianu, M.; Dancus, I.; Gales, S.; Neagu, L.; Petcu, C. [ELI-NP, IFIN-HH, 077125 Bucharest-Magurele (Romania); and others

    2015-02-24

    The measurement of energy spectra of neutrons and gamma rays emitted by nuclei, together with charge particles spectroscopy, are the main tools for understanding nuclear phenomena occurring also in high power laser driven experiments. However, the large number of particles emitted in a very short time, in particular the strong X-rays flash produced in laser-target interaction, impose adaptation of technique currently used in nuclear physics experiment at accelerator based facilities. These aspects are discussed (Section 1) in the context of proposed studies at high power laser system of ELI-NP. Preliminary results from two experiments performed at Titan (LLNL) and ELFIE (LULI) facilities using plastic scintillators for neutron detection (Section 2) and LaBr{sub 3}(Ce) scintillators for gamma detection (Section 3) are presented demonstrating the capabilities and the limitations of the employed methods. Possible improvements of these spectroscopic methods and their proposed implementation at ELI-NP will be discussed as well in the last section.

  17. Gamma-ray imaging and spectroscopy system using room-temperature semiconductor detector elements

    International Nuclear Information System (INIS)

    We report on the design, construction, and testing of a gamma-ray imaging system with spectroscopic capabilities. The imaging system consists of an orthogonal strip detector made from either HgI2 or CdZnTe crystals. The detectors utilize an 8x8 orthogonal strip configuration with 64 effective pixels. Both HgI2 or CdZnTe detectors are 1 cm2 devices with a strip pitch of approximately 1.2 mm (producing pixels of 1.2 mm x 1.2 mm). The readout electronics consist of parallel channels of preamplifier, shaping amplifier, discriminators, and peak sensing ADC. The preamplifiers are configured in hybrid technology, and the rest of the electronics are implemented in NIM and CAMAC with control via a Power Macintosh computer. The software used to readout the instrument is capable of performing intensity measurements as well as spectroscopy on all 64 pixels of the device. We report on the performance of the system imaging gamma-rays in the 20-500 keV energy range and using a pin-hole collimator to form the image. (author)

  18. Implementation of neutron-induced gamma-ray spectroscopy in industrial applications

    International Nuclear Information System (INIS)

    Full text: Neutron based analytical techniques are commonly used in a wide variety of industrial applications, with new applications continually being found. As a result, despite popular concerns about the harmful health effects of radiation the number of these analysers is increasing. This is because neutron-induced gamma-ray techniques have the capability of combining elemental sensitivity with significant penetrating power, enabling non-intrusive and non-destructive bulk elemental measurements to be averaged over a large volume of material. Neutron induced gamma ray spectroscopy has been developed by several groups, including CSIRO Minerals, for on-line measurement of elemental composition in a range of industrial applications in vessels, pipes and on conveyor belts. Compared to those typically found in a scientific laboratory, conditions in industrial plants differ substantially in a number of ways, such as environmental variability, operator skill and training, and shielding requirements. As a result of these differences, equipment and techniques which are used as a matter of course in a laboratory often have to undergo major modification to render them suitable for use in an industrial context. This paper will discuss some of the factors that have to be considered when deciding such matters with particular emphasis on the implications of radiation safety requirements

  19. The determination of 134Cs and 22Na diffusion profiles in granodiorite using gamma spectroscopy

    International Nuclear Information System (INIS)

    Spent nuclear fuel repository safety evaluation today requires both laboratory and in situ field work in order to assess the parameters affecting the sorption and diffusion of radionuclides. Recent investigations at the Grimsel test site suggest that non-conservative errors in transport properties derived from laboratory scale experiments can lead to over-conservative estimates of matrix diffusion depths. As a result, the geosphere's capability to retain radionuclides may be underestimated. In this study the in situ diffusion and the sorption of 134Cs and 22Na into granodiorite were determined using gamma spectroscopy. Autoradiography was used to reveal the minerals into which the radionuclides were sorbed. A rock sample was obtained from the Grimsel underground in situ diffusion test site in Switzerland. In the in situ test, a solution containing several different radionuclides was circulated continuously in a packed-off injection hole for two years and three months in order to study diffusion of the radionuclides into the surrounding bedrock. The gamma measurements show that in the course of the experiment 134Cs diffused 2.5 cm and 22Na 10 cm into the rock matrix, respectively. Caesium was found to have sorbed on mafic minerals biotite and chlorite. Results of this study were used in order to calculate an in situ effective diffusion coefficient for caesium and sodium in Grimsel granodiorite. (author)

  20. Investigation of LaBr3:Ce probe for gamma-ray spectroscopy and dosimetry

    Science.gov (United States)

    Maghraby, Ahmed M.; Alzimami, K. S.; Alkhorayef, M. A.; Alsafi, K. G.; Ma, A.; Alfuraih, A. A.; Alghamdi, A. A.; Spyrou, N. M.

    2014-02-01

    The main thrust of this work is the investigation of performance of relatively new commercial LaBr3:Ce probe (Inspector 1000™ with LaBr3:Ce crystal) for gamma-ray spectroscopy and dosimetry measurements in comparison to LaCl3:Ce and NaI:Tl scintillators. The crystals were irradiated by a wide range of energies (57Co, 22Na, 18F, 137Cs and 60Co). The study involved recording of detected spectra and measurement of energy resolution, photopeak efficiency, internal radioactivity measurements as well as dose rate. The Monte Carlo package, Geant4 Application for Tomographic Emission (GATE) was used to validate the experiments. Overall results showed very good agreement between the measurements and the simulations. The LaBr3:Ce crystal has excellent energy resolution, energy resolutions of (3.37±0.05)% and (2.98±0.07)% for a 137Cs 662 keV and a 60Co 1332 keV gamma-ray point sources respectively, were recorded. The disadvantage of the lanthanum halide scintillators is their internal radioactivity. Inspector 1000™ with LaBr3:Ce scintillator has shown an accurate and quick dose measurements at Positron Emission Tomography (PET) Units which allows accurate assessment of the radiation dose received by staff members compared to the use of electronic personal dosimeters (EPD).

  1. High-precision gamma-ray spectroscopy for enhancing production and application of medical isotopes

    Science.gov (United States)

    McCutchan, E. A.; Sonzogni, A. A.; Smith, S. V.; Muench, L.; Nino, M.; Greene, J. P.; Carpenter, M. P.; Zhu, S.; Chillery, T.; Chowdhury, P.; Harding, R.; Lister, C. J.

    2015-10-01

    Nuclear medicine is a field which requires precise decay data for use in planning radionuclide production and in imaging and therapeutic applications. To address deficiencies in decay data, sources of medical isotopes were produced and purified at the Brookhaven Linear Isotope Producer (BLIP) then shipped to Argonne National Laboratory where high-precision, gamma-ray measurements were performed using Gammasphere. New decay schemes for a number of PET isotopes and the impact on dose calculations will be presented. To investigate the production of next-generation theranostic or radiotherapeutic isotopes, cross section measurements with high energy protons have also been explored at BLIP. The 100-200 MeV proton energy regime is relatively unexplored for isotope production, thus offering high discovery potential but at the same time a challenging analysis due to the large number of open channels at these energies. Results of cross sections deduced from Compton-suppressed, coincidence gamma-ray spectroscopy performed at Lowell will be presented, focusing on the production of platinum isotopes by irradiating natural platinum foils with 100 to 200 MeV protons. DOE Isotope Program is acknowledged for funding ST5001030. Work supported by the US DOE under Grant DE-FG02-94ER40848 and Contracts DE-AC02-98CH10946 and DE-AC02-06CH11357.

  2. Assessment of pollutants in manzala lake using gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    Multielemental analysis of water samples taken from the area of manzala lake in the east-north of river Nile delta of egypt, has been performed. Prompt gamma neutron activation analysis (PGNAA) technique is applied to determine the elemental concentrations. The samples have been irradiated by means of (PGNAA) facility using a Cf 252 isotopic neutron source with a total flux of 1.5 x 105 n cm2 s-1 for 300 min irradiation time. The evaluation of Cd, Gd, Sm, Pb, Zn, Co and Hg as trace elements in these samples is reported. 1 fig., 2 tabs

  3. Fifteenth international symposium on capture gamma-ray spectroscopy and related topics. CGS15. Book of abstracts

    International Nuclear Information System (INIS)

    The proceedings of the fifteenth international symposium on capture gamma-ray spectroscopy and related topics - CGS15 - includes abstract concerning the following topics: nuclear structure, nuclear reactions, nuclear astrophysics, techniques/reactions, nuclear data/reactions, statistical properties, fundamental properties, nuclear reactions/data.

  4. Quasi-optimum gamma and X spectroscopy based on real-time digital techniques

    CERN Document Server

    Pullia, Antonio; Ripamonti, G

    2000-01-01

    An adaptive, self-calibrated instrument for gamma- and X-ray digital spectroscopy is proposed and demonstrated. Most of the typical processing features (pole-zero cancellation, baseline restoration, and shaping) are digitally implemented and optimized. Initialization is performed through a software procedure, which makes the system particularly flexible and allows periodical adaptivity. It is shown that spectroscopy performances are achieved even while using low-cost, low-frequency (5 Ms/s), and relatively low-resolution (12-bit) AD converters. The ADC differential nonlinearity (DNL), for example, is improved of two orders of magnitude, as estimated over the Compton shoulder of a sup 6 sup 0 Co spectrum, owing to an equivalent built-in sliding-scale effect. Using the system with an high-purity germanium (HPGe) detector a resolution of 1.9 keV FWHM (1.6 per mille) is obtained on the 1.17 MeV spectral line of a sup 6 sup 0 Co source. An Integral Nonlinearity (INL) of 0.3 per mille is measured in the range from ...

  5. A miniature modular multichannel analyzer system for automated, low- resolution gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    Throughout the nuclear complex, the demand for measurements of nuclear materials holdup is increasing. Plant-wide campaigns to quantify holdup in ventilation ducts and holdup measurements in support of duct remediation are in progress at most DOE sites. Plans to satisfy more stringent requirements for holdup measurements are being developed. Facility decommissioning that accompanies downsizing the complex will require extensive holdup measurement efforts. In the early phases of planning for the modem complex, holdup measurements for new facilities are being specified at the facility design stage. Beyond the DOE, international inspection activities are relying, increasingly, on holdup measurements for verification. Developments in nondestructive assay technologies in the past decade have provided some support for measurements of this Mx. The user's requirements of ruggedness and reliability have been satisfied with compact gamma-ray detectors and spectroscopy instrumentation, but improvements are still needed in simplicity, portability, and speed. Current portable spectroscopy instruments require user sophistication as well as more than one person for transport between measurement locations. However, it is becoming clear that the real measurement need is the simultaneous operation of dozens of units, each by a single relatively unsophisticated user, to perform thousands of measurements per inventory period. The rapid and reliable conversion of measurement data to holdup quantities is essential

  6. Measurement uncertainty from In-Situ gamma spectroscopy of nonhomogeneous containers and from Laboratory Assay

    International Nuclear Information System (INIS)

    During a D and D or ER process containers of radioactive waste are normally generated. The activity can commonly be determined by gamma spectroscopy, but frequently the measurement conditions are not conducive to precise sample-detector geometries, and usually the radioactive material is not in a homogeneous distribution. What is the best method to accurately assay these containers - sampling followed by laboratory analysis, or in-situ spectroscopy? What is the uncertainty of the final result? To help answer these questions, the Canberra tool ISOCS Uncertainty Estimator [IUE] was used to mathematically simulate and evaluate several different measurement scenarios and to estimate the uncertainty of the measurement and the sampling process. Several representative containers and source distributions were mathematically defined and evaluated to determine the in-situ measurement uncertainty due to the sample non-uniformity. In the First example a typical field situation requiring the measurement of 200-liter drums was evaluated. A sensitivity analysis was done to show which parameters contributed the most to the uncertainty. Then an efficiency uncertainty calculation was performed. In the Second example, a group of 200-liter drums with various types of non-homogeneous distributions was created, and them measurements were simulated with different detector arrangements to see how the uncertainty varied. In the Third example, a truck filled with non-uniform soil was first measured with multiple in-situ detectors to determine the measurement uncertainty. Then composite samples were extracted and the sampling uncertainty computed for comparison to the field measurement uncertainty. (authors)

  7. Investigation of Depleted Uranium Contamination in the south parts of Qatar using Gamma ray spectroscopy and (ICP-MS)

    International Nuclear Information System (INIS)

    Before and during the second Gulf War training of the international forces in the Gulf region, depleted uranium (D U) emanations used in southern parts of Iraq and northern Kuwait and southern part of Saudi Arabia. These activities were led to the contamination of the region with D U. Because of the possibility of creeping D U particles to the south of Qatar.Twenty one sample of soil were collected from the south of Qatar near Saudi borders. The samples were analyzed by two method, inductively coupled plasma mass Spectrometry (ICP-MS) and Gamma ray spectroscopy. Since the isotopic abundance of uranium in D U is different than that in nature, the only evidence of D U contamination is the disruption of the natural isotopic abundance i,e 235U/238U. The measurement shows that the region is not contaminated with depleted uranium since the235U/238U ratio is nearly 0.00709 which is the ratio for natural uranium .Gamma ray spectroscopy methods are well known analytical methods for the determination of most long-lived radionuclides in environmental samples. ICP.MS technique is very sensitive, accurate, rapid and low cost techniques for the determination low level of many long-lived radionuclides, with small sample amount needed for the analysis. Its detection limits comparable to the Gamma ray spectroscopy methods and rapid analytical capacity. However no single analytical technique can be better than other. Each technique has its own strengths and weaknesses. In general, ICP.MS techniques are good complementary to the Gamma ray spectroscopy techniques for the determination of most of long-lived radionuclides .The results of ICP-MS are nearly the same and more accurate than the method of gamma ray spectroscopy which is not effected by the sampling, calibration and statistical error.

  8. Self-absorption corrections in gamma-ray spectrometry applied to norm industrial samples

    International Nuclear Information System (INIS)

    High resolution gamma spectrometry is a versatile non-destructive radiometric technique that makes simultaneous determination of several radionuclides possible with little sample preparation. However, application of self-absorption corrections is a must, especially in the low energy range, if one hopes to obtain correct values of activity concentrations. Usually, NORM samples feature a wide variety of densities and composition, as opposed to the standards used in efficiency calibration, which are often water-based solutions. For that reason self-absorption effects must be considered individually in every sample. In this work an experimental and a semi-empirical method of self-absorption correction were applied to NORM samples and compared with each other in order to establish best practice in relation to the circumstances of an individual laboratory. Following the experimental methodology, transmission measurements of absorption factors with point sources were carried out, while the semi-experimental methodology involved the application of the EFFTRAN code, based on the 'efficiency transfer' principle. Both methods were validated by applying them to a set of spiked NORM matrices coming from the TiO2 industry located in the south-west of Spain in order to determine the flow of several radionuclides from the Uranium and Thorium series though the production process. The main advantages and disadvantages of the two approaches used are highlighted, focusing on the low energy range (46-200 keV). EFFTRAN qualities are its ease of use, its short-run time and good performance with samples of a well-known composition, while the transmission technique can be applied almost under any circumstances, providing that a suitable set of point sources covering the energy range of interest is at hand. (authors)

  9. Applying natural gamma spectrometry to solution of oil and gas exploration problems

    International Nuclear Information System (INIS)

    In addition to a total radioactivity of rocks the multichannel spectral gamma-ray log (SGR) allows one to determine concentrations of natural radioactive elements K, U (Ra), and Th. This substantially improves the information content of gamma-ray log and allows one to solve complicated E and P problems, provides the reliability and unambiguity of geological interpretation, particularly under complicated geological conditions - in polymict sandstone, thin-layered formations, bitumen-saturated formations, etc. The instrumentation-methodical system of the multichannel SGRL tool MARKA-SGR was developed by the GEOKON company and was widely tested in the terrigeneous Devonian deposits of the Tatarstan and Bazhenian series of the Surgut arch. As known each mineral depending on its structure and sedimentation conditions contains a specific concentration of natural radioactive elements. In turn, the quality of reservoir rocks, their reaction with injected chemicals, and quality of cap rocks depend crucially on the content of specific minerals and their associations. To determine the elemental composition of rocks applied is a technology for estimating the component composition from a combination of well logs including the SGRL. This technology includes a number of petrophysical analyses, petrographic examinations included, and modeling of petrophysical relationships between particular components and geophysical characteristics of rocks. Based on such relationships one can interpret well logs more adequately and estimate the content of specific rock components. By way of example presented is application of this technology to the determining the contents of clay minerals in terrigenous Devonian deposits of Romashkin oil field, Tatarstan. In order to perform a petrophysical tuning of well log interpretation models we made standard core analyses, determined concentrations of K, U(Ra), and Th, made petrophysical examinations (structural X-ray analysis, scanning electron

  10. Design of high-linear CMOS circuit using a constant transconductance method for gamma-ray spectroscopy system

    International Nuclear Information System (INIS)

    We propose a novel circuit to be applied to the front-end integrated circuits of gamma-ray spectroscopy systems. Our circuit is designed as a type of current conveyor (ICON) employing a constant-gm (transconductance) method which can significantly improve the linearity in the amplified signals by using a large time constant and the time-invariant characteristics of an amplifier. The constant-gm method is obtained by a feedback control which keeps the transconductance of the input transistor constant. To verify the performance of the propose circuit, the time constant variations for the channel resistances are simulated with the TSMC 0.18μm transistor parameters using HSPICE, and then compared with those of a conventional ICON. As a result, the proposed ICON shows only 0.02% output linearity variation and 0.19% time constant variation for the input amplitude up to 100 mV. These are significantly small values compared to a conventional ICON's 1.39% and 19.43%, respectively, for the same conditions.

  11. Proceeding of the workshop on gamma-ray spectroscopy utilizing heavy-ion, photon and RI beams

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Masumi; Sugita, Michiaki; Hayakawa, Takehito [eds.

    1998-03-01

    Three time since 1992, we have held the symposia entitled `Joint Spectroscopy Experiments Utilizing JAERI Tandem-Booster Accelerator` at the Tokai Research Establishment. In the symposia, we have mainly discussed the plans of experiments to be done in this joint program. The joint program started in 1994. Several experiments have been made since and some new results have already come up. This symposium `Gamma-ray Spectroscopy utilizing heavy-ion, Photon and RI beams` was held at Tokai Research Establishment of JAERI. Because this symposium is the first occasion after the program started, the first purpose of the symposium is to present and discuss the experimental results so far obtained using the JAERI Tandem-Booster. The second purpose of the symposium is to discuss new possibilities of gamma-ray spectroscopy using new resources such as RI-beam and Photon-beam. The participants from RIKEN, Tohoku University and JAERI Neutron Science Research Center presented the future plans of experiments with RI-beam at each facility. Compared with these nuclear beams, photon beam provides a completely new tool for the {gamma}-ray spectroscopy, which is achieved by inverse Compton scattering between high-energy electron and laser beams. The 23 of the presented papers are indexed individually. (J.P.N.)

  12. New approach to the nuclear in beam {gamma} spectroscopy of neutron rich nuclei at N=20 using projectile fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Jimenez, M.J.; Saint-Laurent, M.G.; Achouri, L.; Daugas, J.M. [Grand Accelerateur National d`Ions Lourds, 14 - Caen (France); Belleguic, M.; Azaiez, F.; Bourgeois, C. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Stanoiu, M.; Borcea, C. [Institute of Atomic Physics, Bucharest (Romania); Angelique, J.C. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire] [and others

    1999-11-01

    The structure of nuclei far from stability around {sup 32}Mg have been recently investigated by means of a novel method. In-beam {gamma}-decay spectroscopy of a large number of exotic neutron-rich nuclei produced by projectile fragmentation of a {sup 36}S projectile has been performed, using coincidences between the recoil fragments collected at the focal plane of SPEG spectrometer and {gamma}-rays emitted at the target location. Preliminary results on both the population mechanism and the decay of excited states in nuclei around {sup 32}Mg are presented. (author) 24 refs.

  13. Internet accessible hot cell with gamma spectroscopy at the Missouri S and T nuclear reactor

    International Nuclear Information System (INIS)

    Highlights: → A dual-chambered internet-accessible heavily shielded facility has been built. → The facility allows distance users to analyze neutron irradiated samples remotely. → The Missouri S and T system uses computer automation with user feedback. → The system can analyze multiple samples and assist several researchers concurrently. - Abstract: A dual-chambered internet-accessible heavily shielded facility with pneumatic access to the University of Missouri Science and Technology (Missouri S and T) 200 kW Research Nuclear Reactor (MSTR) core has been built and is currently available for irradiation and analysis of samples. The facility allows authorized distance users engaged in collaborative activities with Missouri S and T to remotely manipulate and analyze neutron irradiated samples. The system consists of two shielded compartments, one for multiple sample storage, and the other dedicated exclusively for radiation measurements and spectroscopy. The second chamber has multiple detector ports, with graded shielding, and has the capability to support gamma spectroscopy using radiation detectors such as an HPGe detector. Both these chambers are connected though a rapid pneumatic system with access to the MSTR nuclear reactor core. This new internet-based system complements the MSTR's current bare pneumatic tube (BPT) and cadmium lined pneumatic tube (CPT) facilities. The total transportation time between the core and the hot cell, for samples weighing 10 g, irradiated in the MSTR core, is roughly 3.0 s. This work was funded by the DOE grant number DE-FG07-07ID14852 and expands the capabilities of teaching and research at the MSTR. It allows individuals who do not have on-site access to a nuclear reactor facility to remotely participate in research and educational activities.

  14. Measuring Radionuclides Concentration in Rice Field Soils Using Gamma Spectroscopy in Northern Iran

    Directory of Open Access Journals (Sweden)

    MZ Zareh

    2012-02-01

    Full Text Available Background: A few elements of soil are radioactive. Soil can transfer radionuclide into plants feeding human. Sometimes their levels are as high as to be concern of human healthy. Rice has an important share for Iranian foods especially in north of Iran. Therefore we decided to obtain radionuclides concentration emitting g rays in Lahijan City (Northern Iran rice fields using g spectroscopy.Methods: Twenty eight samples from rice field's soils and 12 samples from superficial soils were collected at a square of 10*10 m2 to get 2kg weight. To make dry samples were put into oven at 105oC for 24h. Then they were milled and 950 gr of each sample was transferred to Marinelli container with 1000cc volume, sealed and left for 40 days to get secular equilibrium. After measuring Ph, Electric conductivity and organic carbon, g spectroscopy was done to get sample gamma spectrum at 2000-6000 sec using HpGe detector.Results: It was found 226Ra activity in rice fields of 29.273±0.72 Bqkg-1 and city soil of 31.02±1.1 Bqkg-1 and also 232Th activity of 37.47±1.12 Bqkg-1 for rice fields' soils and 40.47±1.68 Bqkg-1 for city soil were in standard mode.Conclusion: 40K activities mean value according to UNSCEAR; 2000 was found a little greater than standard. A little value of 137Cs was found in Lahijan rice fields and city soils that could be as a result of Chernobyl accident. In except of 137Cs, for three other under studied city soil elements, activities were greater than that of rice fields.

  15. gamma-ray DBSCAN: a clustering algorithm applied to Fermi-LAT gamma-ray data. I. Detection performances with real and simulated data

    CERN Document Server

    Tramacere, A

    2012-01-01

    The Density Based Spatial Clustering of Applications with Noise (DBSCAN) is a topometric algorithm used to cluster spatial data that are affected by background noise. For the first time, we propose the use of this method for the detection of sources in gamma-ray astrophysical images obtained from the Fermi-LAT data, where each point corresponds to the arrival direction of a photon. We investigate the detection performance of the gamma-ray DBSCAN in terms of detection efficiency and rejection of spurious clusters, using a parametric approach, and exploring a large volume of the gamma-ray DBSCAN parameter space. By means of simulated data we statistically characterize the gamma-ray DBSCAN, finding signatures that differentiate purely random fields, from fields with sources. We define a significance level for the detected clusters, and we successfully test this significance with our simulated data. We apply the method to real data, and we find an excellent agreement with the results obtained with simulated data....

  16. Neutron Activation Analysis and High Resolution Gamma-Ray Spectrometry Applied to Areal Elemental Distribution Studies

    International Nuclear Information System (INIS)

    Schuiling (1967) applied both 'metallogenetic province' and continental drift principles to a study of the world-wide distribution of tin. A plot of tin deposit occurrences on the continents reconstituted as 'Pangeae' yielded 'tin belts' joining intercontinentally between the Americas, Africa and Europe. Discussions with Sir John Cockcroft and Sir Edward Bullard, in April 1967, led to this study of the applicability of automated, instrumental thermal neutron activation analysis techniques to large-scale areal elemental distribution determinations related to continental drift and to metallogenesis. The Enchanted Rock batholith, Llano, Texas, was selected as an initial area in which to apply this method on the basis of the availability of independent geochemical information concerning the pluton from Hutchinson (1956), Billings (1963) and Ragland (1968). Rock samples, including points from areas outside the batholith, were obtained at each of 16 sampling sites. One-gram rock samples were irradiated in a thermal neutron flux of ≈2 x 1012 n/cm2 s for 2 hours. Six trace elements (Hf, Ta, Co, Eu, Sc and La), and one minor element (Fe), were determined by gamma-ray spectrometry utilizing a 19 cm3 Ge(Li) detector and a 3200-channel analyser, and were areally mapped. The results indicate continuous trends in each trace element, through various rock types, over a distance of greater than 50 miles. The trace elements of pyrite, chalcopynte and sphalerite obtained from the Philippine Islands were measured in order to apply this procedure to minerals in a location where their areal extent has not previously been extensively studied. The methodology described above was repeated. A set of average element abundances in chalcopynte, pyrite and sphalerite is suggested on which to base the presence or absence of an element province or combined elements provinces. Preliminary results indicate the presence of a gold province in the northwestern part of Luzon Island. This technique

  17. Exact method for determining subsurface radioactivity depth profiles from gamma spectroscopy measurements

    CERN Document Server

    Van Siclen, Clinton DeW

    2011-01-01

    Subsurface radioactivity may be due to transport of radionuclides from a contaminated surface into the solid volume, as occurs for radioactive fallout deposited on soil, or from fast neutron activation of a solid volume, as occurs in concrete blocks used for radiation shielding. For purposes including fate and transport studies of radionuclides in the environment, decommissioning and decontamination of radiation facilities, and nuclear forensics, an in situ, nondestructive method for ascertaining the subsurface distribution of radioactivity is desired. The method developed here obtains a polynomial expression for the radioactivity depth profile, using a small set of gamma-ray count rates measured by a collimated detector directed towards the surface at a variety of angles with respect to the surface normal. To demonstrate its capabilities, this polynomial method is applied to the simple case where the radioactivity is maximal at the surface and decreases exponentially with depth below the surface, and to the ...

  18. Application of airborne gamma-ray spectrometry in soil/regolith mapping and applied geomorphology

    International Nuclear Information System (INIS)

    Gamma-ray spectrometric surveys are an important source of information for soil, regolith and geomorphological studies, as demonstrated by the interpretation of airborne surveys in Western Australia, central New South Wales and north Queensland. Gamma-rays emitted from the ground surface relate to the primary mineralogy and geochemistry of the bedrock, and the secondary weathered materials. Weathering modifies the distribution and concentration of radioelements from the original bedrock source. Once the radioelement response of bedrock and weathered materials is understood, the gamma-ray data can provide information on geomorphic processes and soil/regolith properties, including their mineralogy, texture, chemistry and style of weathering. This information can contribute significantly to an understanding of the weathering and geomorphic history of a region and, therefore, has the potential to be used in developing more effective land-management strategies and refining geochemical models in support of mineral exploration. Gamma-ray imagery is enhanced when combined with Landsat TM bands and digital elevation models (DEM). This synergy enables geochemical information derived from the gamma-ray data to be interpreted within a geomorphic framework. Draping gamma-ray images over DEMs as 3D landscape perspective views aids interpretation and allows the interpreter to visualise complex relationships between the gamma-ray response and landform features. 44 refs.,1 tab., 11 figs

  19. Gamma-radiography techniques applied to quality control of welds in water pipe lines

    International Nuclear Information System (INIS)

    Non-destructive testing of welds may be done by the gamma-radiography technique, in order to detect the presence or absence of discontinuities and defects in the bulk of deposited metal and near the base metal. Gamma-radiography allows the documentation of the test with a complete inspection record, which is a fact not common in other non-destructive testing methods. In the quality control of longitudinal or transversal welds in water pipe lines, two exposition techniques are used: double wall and panoramic exposition. Three different water pipe lines systems have analysed for weld defects, giving a total of 16,000 gamma-radiographies. The tests were made according to the criteria established by the ASME standard. The principal metallic discontinuites found in the weld were: porosity (32%), lack of penetration (29%), lack of fusion (20%), and slag inclusion (19%). The percentage of gamma-radiographies showing welds without defects was 39% (6168 gamma-radiographies). On the other hand, 53% (8502 gamma-radiographies) showed the presence of acceptable discontinuities and 8% (1330 gamma-radiographies) were rejected according to the ASME standards

  20. Applying light-emitting diodes with narrowband emission features in differential spectroscopy.

    Science.gov (United States)

    Sihler, Holger; Kern, Christoph; Pöhler, Denis; Platt, Ulrich

    2009-12-01

    LEDs are a promising new type of light source for differential optical absorption spectroscopy (DOAS). Varying differential structures in the emission spectrum of LEDs, however, display a potentially severe problem. We show that the structures, which originate from a Fabry-Pérot etalon, may be removed by tilting the emitter, which at the same time increases the radiant flux coupled into the subsequent optical system. The results of long-path DOAS measurements, where we apply our method on a blue LED for the suppression of periodic structures, are also presented. PMID:19953172

  1. Computerized system for data acquisition and processing for gamma and alpha spectroscopy analysis

    International Nuclear Information System (INIS)

    This paper describes the implantation of a computerized system for data acquisition and processing in real time for gamma and alpha spectroscopy analyses. The system is composed by a IBM-PC/XT compatible microcomputer and four multi-channel-analyzers (MCAs). The MCAs work concurrently and they are controlled by the microcomputer, that manages the data acquisition and manipulates the data to produce graphics and reports. For the communication between the MCAs and the microcomputer it was developed a special interface, which fits in one of the slots of the PC. The communication protocol was based in the microcomputer action, which enables the data transmission, byte-by-byte. The control software makes a polling in the input channels, acquires the available data and saves them in vectors in the main memory. At the end of a full spectrum transmission, the data are saved in a hard disk. It were developed faults detection and errors treatment routines in real time to preserve the data integrity. The language used for the control program was Turbo Pascal 5.0. (author)

  2. Concept of capture credit based on neutron-induced gamma ray spectroscopy

    International Nuclear Information System (INIS)

    Capture credit (CapC) based on neutron-induced gamma ray spectroscopy (NIGS) is proposed to confirm the subcriticality of fuel debris in which nuclear fuel and structural materials are co-melted or mixed. By NIGS, rates of some capture reactions can be measured in relation to fission reactions. By the ratio, we can credit the negative reactivity inserted by the capture reactions. The theory of CapC is described. In order to demonstrate the benefit to take CapC for storage of the fuel debris, numerical simulations are performed for a hypothetical array of canisters in which the fuel debris is stored. A procedure of CapC based on NIGS is also proposed, which consists of several technologies: (1) NIGS, (2) simulations of a response and an efficiency of the γ ray detection, and (3) unfolding of the γ ray pulse height spectrum to obtain reaction rates. Experimental studies of NIGS have been launched in Kyoto university critical assembly facility. NIGS is firstly studied for simulated fuel debris of a few kinds of mixture of stainless steel and uranium in subcritical systems. The measured γ ray pulse height spectra and preliminary analyses indicate that CapC based on NIGS is worth to be investigated further for the efficient storage of fuel debris. (author)

  3. Characterization of Solid Building Structures with NaI Gamma Spectroscopy

    International Nuclear Information System (INIS)

    This paper presents an in-situ gamma spectroscopy measurement setup, which utilizes a NaI detector for clearance measurements of concrete building structures. As such an apparatus can be operated at room temperature, large and costly supporting accessories are not required. This is a major improvement in comparison to existing approaches that work with semiconductor technology, e.g., high pure germanium detectors. The method under discussion allows to create versatile and handy measurement systems, which lower cost and time efforts, required for characterization measurements during the disassembly of nuclear power plants, considerably. This novel characterization method has been developed jointly by E.ON and the University Rostock to foster the dismantling activities of E.ON nuclear power plants. The regulatory acceptance for this method has been granted for the facility Nuclear Power Plant Isar (KKI) in July 2013. This paper details the method under discussion and how an acceptance has been reached, according to applicable legislation. Furthermore, a comparison with state of the art characterization methods plus experiences from the practical application of the method will be shown. (authors)

  4. Geochemical mapping of the Moon by orbital gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    Chemical compositions of the surfaces of the moon and certain planetary bodies can be determined by orbital γ-ray spectroscopy. The major sources of γ-ray lines (and of radionuclides) in the moon are the decay of the primordial radioelements (U, Th,and 40K) and nuclear reactions induced by the bombardment of the moon by cosmic-ray particles. The major cosmogenic γ-ray lines are produced by neutron nonelastic scattering and neutron capture reactions. The fluxes of γ-ray lines expected from the moon for each major source have been calculated. Gamma-rays from the moon were measured by γ-ray spectrometers during the Apollo 15 and 16 missions. The preliminary analysis of the data show that 0 and Si vary little over the moon's surface, that Mg, Fe, and Ti have higher concentrations in the maria than in the lunar highlands, and that the radioelements are significantly more abundant in and near the western nearside maria than in the rest of the moon. (U.S.)

  5. Stimulus generation technique for code simulation of FPGA based gamma spectroscopy system

    International Nuclear Information System (INIS)

    Full-text:The aim of this study is to develop a software that can systematically generate stimulus required for code simulation (functional and timing) of new digital processors in gamma spectroscopy system. Software must be able to produce stimulus that emulate ADC data of charge sensitive amplifier (CSA) output signal. Signal parameters such as pulse shape, amplitude, pulse width and count rate should be adjustable while allowing options such as pulse pile-up and random pulse events. To fulfill this objective, a pulse generator software PulseGEN has been developed. The software GUI is designed to operate in two modes, Single/Pile-Up Mode and Continuous Random Mode. Its ADC module simulates real-time ADC sampling. The output can be saved as input stimulus to test various functions of digital processors such as pulse height measurements, pile-up detection and correction, as well as random pulse detection and measurement that is similar to the actual real-time measurement. PulseGEN results have been compared and verified against commercial charge sensitive amplifier with NaI detector and NIM pulser. (author)

  6. Low background gamma spectroscopy and neutron activation analysis for Double Chooz

    International Nuclear Information System (INIS)

    To check the radiopurity of detector components of the reactor neutrino oscillation experiment Double Chooz, low background gamma spectroscopy measurements have been performed at the Garching underground lab using a 150% germanium counter surrounded by active and passive shielding systems. The active shielding consists of an anti-Compton veto and a muon veto. Upper limits on the activities of radioisotopes originating from the uranium and thorium decay chains, as well as potassium-40, can be given in the order of 10-10 g/g. An even higher sensitivity can be obtained by neutron activation analysis performed on the wavelength shifter PPO and the acrylics used for the detector tank. The samples were irradiated for ten minutes at the FRM2 with a thermal neutron flux of (1.63±0.05).1013 cm-2s-1. Thereafter, the spectra of the irradiated samples were recorded using the germanium counting system mentioned above, mainly focussing on the isotope potassium-42. The content of potassium-40 could be determined to be of the order of 10-11 g/g.

  7. A Multi-Contact, Low Capacitance HPGe Detector for High Rate Gamma Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cox, Christopher [XIA LLC, Hayward, CA (United States)

    2014-12-04

    The detection, identification and non-destructive assay of special nuclear materials and nuclear fission by-products are critically important activities in support of nuclear non-proliferation programs. Both national and international nuclear safeguard agencies recognize that current accounting methods for spent nuclear fuel are inadequate from a safeguards perspective. Radiation detection and analysis by gamma-ray spectroscopy is a key tool in this field, but no instrument exists that can deliver the required performance (energy resolution and detection sensitivity) in the presence of very high background count rates encountered in the nuclear safeguards arena. The work of this project addresses this critical need by developing a unique gamma-ray detector based on high purity germanium that has the previously unachievable property of operating in the 1 million counts-per-second range while achieving state-of-the-art energy resolution necessary to identify and analyze the isotopes of interest. The technical approach was to design and fabricate a germanium detector with multiple segmented electrodes coupled to multi-channel high rate spectroscopy electronics. Dividing the germanium detector’s signal electrode into smaller sections offers two advantages; firstly, the energy resolution of the detector is potentially improved, and secondly, the detector is able to operate at higher count rates. The design challenges included the following; determining the optimum electrode configuration to meet the stringent energy resolution and count rate requirements; determining the electronic noise (and therefore energy resolution) of the completed system after multiple signals are recombined; designing the germanium crystal housing and vacuum cryostat; and customizing electronics to perform the signal recombination function in real time. In this phase I work, commercial off-the-shelf electrostatic modeling software was used to develop the segmented germanium crystal geometry

  8. Digitized detection of gamma-ray signals concentrated in narrow time windows for transient positron annihilation lifetime spectroscopy

    International Nuclear Information System (INIS)

    A pulsed slow-positron beam generated by an electron linear accelerator was directly used for positron annihilation lifetime spectroscopy without any positron storage devices. A waveform digitizer was introduced to simultaneously capture multiple gamma-ray signals originating from positron annihilation events during a single accelerator pulse. The positron pulse was chopped and bunched with the chopper signals also sent to the waveform digitizer. Time differences between the annihilation gamma-ray and chopper peaks were calculated and accumulated as lifetime spectra in a computer. The developed technique indicated that positron annihilation lifetime spectroscopy can be performed in a 20 μs time window at a pulse repetition rate synchronous with the linear accelerator. Lifetime spectra of a Kapton sheet and a thermally grown SiO2 layer on Si were successfully measured. Synchronization of positron lifetime measurements with pulsed ion irradiation was demonstrated by this technique

  9. Self-absorption theory applied to rocket measurements of the nitric oxide (1, 0) gamma band in the daytime thermosphere

    Science.gov (United States)

    Eparvier, F. G.; Barth, C. A.

    1992-01-01

    Observations of the UV fluorescent emissions of the NO (1, 0) and (0, 1) gamma bands in the lower-thermospheric dayglow, made with a sounding rocket launched on March 7, 1989 from Poker Flat, Alaska, were analyzed. The resonant (1, 0) gamma band was found to be attenuated below an altitude of about 120 km. A self-absorption model based on Holstein transmission functions was developed for the resonant (1, 0) gamma band under varying conditions of slant column density and temperature and was applied for the conditions of the rocket flight. The results of the model agreed with the measured attenuation of the band, indicating the necessity of including self-absorption theory in the analysis of satellite and rocket limb data of NO.

  10. Sensitivity of whole human teeth to fast neutrons and gamma-rays estimated by L-band EPR spectroscopy

    International Nuclear Information System (INIS)

    This paper reports the first attempt to use L-band spectroscopy for estimating the sensitivity of whole teeth to fast neutrons and gamma-rays. Three teeth were successively irradiated first with fast neutrons with a wide energy spectrum (mean energy around 30 MeV) up to ∼160 Gy and then with gamma-rays up to ∼14 Gy. After each irradiation, L-band (∼1 GHz) EPR spectra of each whole tooth surrounded by the surface-coil resonator were recorded, yielding a single composite line principally due to CO2- and native radicals. The sensitivities are estimated by the slopes of the linear dose response curves of the dosimetric CO2- radicals. The ratios of the gamma/neutron sensitivities were found to be in the range 8-9 (±2) for the three teeth

  11. Designing and developing of data evaluation and analysis software applied to gamma-ray spectrometry

    International Nuclear Information System (INIS)

    This study is intended to design and develop software for gamma spectral data evaluation and analysis suitable for a variety of gamma-ray spectrometry systems. The software is written in Visual C++. It is designed to run under Microsoft Windows Operating System. The software is capable of covering all the necessary steps for spectral data evaluation and analysis of the collected data. These include peak search, energy calibration, gross and net peak area calculation, peak centroid determination and peak width calculation of the derived gamma-ray peaks. The software offers the ability to report qualitative and quantitative results. The analysis includes: Peak position identification (qualitative analysis) and calculating of its characteristics; Net peak area calculation by subtracting background; Radioactivity estimation (quantitative analysis) using comparison method for gamma peaks from any radioisotopes present during counting; Radioactivity estimation (quantitative analysis) after efficiency calibration; Counting uncertainties calculation; Limit of detection (LOD) estimation. (author)

  12. A gamma-ray detector array for joint spectroscopy experiments at the JAERI tandem-booster facility

    CERN Document Server

    Furuno, K; Komatsubara, T; Furutaka, K; Hayakawa, T; Kidera, M; Hatsukawa, Y; Matsuda, M; Mitarai, S; Shizuma, T; Saitoh, T R; Hashimoto, N; Kusakari, H; Sugawara, M; Morikawa, T

    1999-01-01

    A compact array for gamma-ray spectroscopy developed for the joint experiment at the Japan Atomic Energy Research Institute is described. It consists of an array of 11 Compton suppressed Ge detectors, a 4 pi silicon detector array for charged particle measurements, a position-sensitive silicon detector for experiments on Coulomb excitation and a conversion-electron spectrometer. The details of the detectors and new experimental results obtained with the compact array are also described.

  13. Characterization of dielectric barrier discharge in air applying current measurement, numerical simulation and emission spectroscopy

    CERN Document Server

    Rajasekaran, Priyadarshini; Awakowicz, Peter

    2012-01-01

    Dielectric barrier discharge (DBD) in air is characterized applying current measurement, numerical simulation and optical emission spectroscopy (OES). For OES, a non-calibrated spectrometer is used. This diagnostic method is applicable when cross-sectional area of the active plasma volume and current density can be determined. The nitrogen emission in the spectral range of 380 nm- 406 nm is used for OES diagnostics. Electric field in the active plasma volume is determined applying the measured spectrum, well-known Frank-Condon factors for nitrogen transitions and numerically- simulated electron distribution functions. The measured electric current density is used for determination of electron density in plasma. Using the determined plasma parameters, the dissociation rate of nitrogen and oxygen in active plasma volume are calculated, which can be used by simulation of the chemical kinetics.

  14. Quantification by Raman spectroscopy of the gamma radiation effects in water purification; Cuantificacion por espectroscopia Raman de los efectos de la radiacion gamma en la purificacion de agua

    Energy Technology Data Exchange (ETDEWEB)

    Perez C, V.M.; Santiago J, P.; Castano, V.M. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1999-07-01

    The world problem about water pollution has been confronted by traditional methods such as: chlorination, filtration, etc. In this work is presented an alternative method, which consists in to radiate different concentrations of simulated polluted water (purified water + thinner) at different gamma radiation doses. The structural changes were analysed by Raman spectroscopy. Using a 52.5 Krad dose it was possible to eliminate all the thinner chemical linkages, which appear in the Raman spectra corresponding to the 87.5/12.5 water/thinner mixture. (Author)

  15. Potential radionuclide emissions from stacks on the Hanford site, Part 2: Dose assessment methodology using portable low-resolution gamma spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, J.M. [Westinghouse Hanford Company, Richland, WA (United States)

    1995-02-01

    In September 1992, the Westinghouse Hanford Company began developing an in situ measurement method to assess gamma radiation emanating from high-efficiency particulate air filters using portable low-resolution gamma spectroscopy. The purpose of the new method was to assess radioactive exhaust stack air emissions from empirical data rather than from theoretical models and to determine the potential unabated dose to an offsite theoretical maximally exposed individual. In accordance with Title 40, Code of Federal Regulations, Part 61, Subpart H, {open_quotes}National Emission Standards for Hazardous Air Pollutants{close_quotes}, stacks that have the potential to emit {ge} 1 {mu}Sv y{sup {minus}1} (0.1 mrem y{sup {minus}1}) to the maximally exposed individual are considered {open_quotes}major{close_quotes} and must meet the continuous monitoring requirements. After the method was tested and verified, the U.S. Environmental Protection Agency, Region 10, approved its use in June 1993. Of the 125 stacks operated by the Westinghouse Hanford Company, 22 were targeted for evaluation by this method, and 15 were assessed. (The method could not be applied at seven stacks because of excessive background radiation or because no gamma emitting particles appear in the emission stream.) The most significant result from this study was the redesignation of the T Plant main stack. The stack was assessed as being {open_quotes}minor{close_quotes}, and it now only requires periodic confirmatory measurements and meets federally imposed sampling requirements.

  16. Conformational solution studies of neuropeptide gamma using CD and NMR spectroscopy.

    Science.gov (United States)

    Rodziewicz-Motowidło, Sylwia; Brzozowskl, Krzysztof; Legowska, Anna; Liwo, Adam; Silbering, Jerzy; Smoluch, Marek; Rolka, Krzysztof

    2002-05-01

    Neuropeptide gamma is one of the largest members of the tachykinin family of peptides, exhibiting strong agonistic activity towards the NK-2 tachykinin receptor. This peptide was synthesized by the solid-phase method using the Fmoc chemistry. Circular-dichroism spectroscopy (CD) investigations of this peptide were performed in phosphate buffer, in the presence of sodium dodecylsulphate (SDS) micelles and trifluoroethanol (TFE) solutions and in DMSO-d6 using the 2D NMR technique in conjunction with two different theoretical approaches. The first assumes multiconformational equilibrium of the peptide studied characterized by the values of statistical weights of low-energy conformations. These calculations were performed using three different force fields ECEPP/3, AMBER4.1 and CHARMM (implemented in the X-PLOR program). The second method incorporates interproton distance and dihedral angle constraints into the starting conformation using the Simulated Annealing algorithm (X-PLOR program). The CD experiments revealed that although the peptide studied is flexible in polar solvents, a tendency to adopt a helical structure was observed in the hydrophobic environment. The NMR data (NOE effects) indicate a helical or reverse structure in the Ile7-His12 fragment of the peptide studied in DMSO-d6 solution. The results obtained cannot be interpreted in terms of a single conformation. Most of the conformations obtained with the ECEPP/3 force field possess a high content of a helical structure. None of the conformers, obtained with the AMBER4.1 and CHARMM force fields, can be considered as the dominant one. In all conformations several beta-turns were detected and in some cases gamma-turns were also found. But in fact, it is rather difficult to select the position of the secondary element(s) present in the structure of NPgamma in solution. All conformers calculated with the X-PLOR program (with using NMR derived distance and torsion angle constraints) are stabilized by several

  17. Detection of explosive substances by tomographic inspection using neutron and gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    In recent years the detection and identification of hazardous materials has become increasingly important. This work discusses research and development of a technique which is capable of detecting and imaging hidden explosives. It is proposed to utilise neutron interrogation of the substances under investigation facilitating the detection of emitted gamma radiation and scattered neutrons. Pulsed fast neutron techniques are attractive because they can be used to determine the concentrations of the light elements (hydrogen, carbon, nitrogen, and oxygen) which can be the primary components of explosive materials. Using segmented High Purity Ge (HPGe) detectors and digital pulse processing [R.J. Cooper, G. Turk, A.J. Boston, H.C. Boston, J.R. Cresswell, A.R. Mather, P.J. Nolan, C.J. Hall, I. Lazarus, J. Simpson, A. Berry, T. Beveridge, J. Gillam, R.A. Lewis, in: Proceedings of the 7th International Conference on Position Sensitive Detectors, Nuclear Instruments and Methods A, in press; I. Lazarus, D.E. Appelbe, A. J. Boston, P.J. Coleman-Smith, J.R. Cresswell, M. Descovich, S.A.A. Gros, M. Lauer, J. Norman, C.J. Pearson, V.F.E. Pucknell, J.A. Sampson, G. Turk, J.J. Valiente-Dobon, IEEE Trans. Nucl. Sci., 51 (2004) 1353; R.J. Cooper, A.J. Boston, H.C. Boston, J.R. Cresswell, A.N. Grint, A.R. Mather, P.J. Nolan, D.P. Scraggs, G. Turk, C.J. Hall, I. Lazarus, A. Berry, T. Beveridge, J. Gillam, R.A. Lewis, in: Proceedings of the 11th International Symposium on Radiation Measurements and Application, 2006. ] the scatter path of incident photons can be reconstructed to determine the origin of the gamma-rays without the need for mechanical collimation by applying the Compton camera principle [V. Schonfelder, A. Hirner, K. Schneider, Nucl. Instr. and Meth. 107 (1973) 385; R.W. Todd, J.M. Nightingale, D.B. Everett, Nature 251 (1974) 132. ]. In addition, it is proposed to utilise the scattered neutrons which recoil from the materials being assayed, detecting them with a fast

  18. Gamma ray spectroscopy of soil samples from apple orchards in Lamingo dam and Vom area in Jos, Plateau State, Nigeria

    International Nuclear Information System (INIS)

    Five samples each were collected from the apple orchards in Lamingo dam and Vom area of Jos East and Jos South local government areas respectively. The samples were allowed to decay for three weeks to ensure efficiency in acquiring the radionuclides. The samples were analyzed using Gamma Ray spectroscopy. Barium- 204 with gamma activity energy level 1765.50keV was used to check the presence of Uranium-235 in the samples. The results showed that samples Lams 2,3,4 and Voms 1,4,5 had high gamma activity energy levels of 2436.356keV, l837.24keV 2928.37 keV and 1656.32keV, 1635.48keV, 2351.87keV respectively as compared to (204B). While Lams 1,5 and Voms 2,3 had relatively lower gamma activity energy levels of 1325.23KeV, 1272.73keV and 1462.61KeV, 1183.24keV respectively. The samples with high gamma activity energy levels imply that radionuclide in the form of 235U is present in trace amounts in the sampled areas. This can affect the output of apples cultivated in such areas as the chemical composition or structure of plants will be altered.

  19. Development of a Small-Sized, Flexible, and Insertable Fiber-Optic Radiation Sensor for Gamma-Ray Spectroscopy.

    Science.gov (United States)

    Yoo, Wook Jae; Shin, Sang Hun; Lee, Dong Eun; Jang, Kyoung Won; Cho, Seunghyun; Lee, Bongsoo

    2015-01-01

    We fabricated a small-sized, flexible, and insertable fiber-optic radiation sensor (FORS) that is composed of a sensing probe, a plastic optical fiber (POF), a photomultiplier tube (PMT)-amplifier system, and a multichannel analyzer (MCA) to obtain the energy spectra of radioactive isotopes. As an inorganic scintillator for gamma-ray spectroscopy, a cerium-doped lutetium yttrium orthosilicate (LYSO:Ce) crystal was used and two solid-disc type radioactive isotopes with the same dimensions, cesium-137 (Cs-137) and cobalt-60 (Co-60), were used as gamma-ray emitters. We first determined the length of the LYSO:Ce crystal considering the absorption of charged particle energy and measured the gamma-ray energy spectra using the FORS. The experimental results demonstrated that the proposed FORS can be used to discriminate species of radioactive isotopes by measuring their inherent energy spectra, even when gamma-ray emitters are mixed. The relationship between the measured photon counts of the FORS and the radioactivity of Cs-137 was subsequently obtained. The amount of scintillating light generated from the FORS increased by increasing the radioactivity of Cs-137. Finally, the performance of the fabricated FORS according to the length and diameter of the POF was also evaluated. Based on the results of this study, it is anticipated that a novel FORS can be developed to accurately measure the gamma-ray energy spectrum in inaccessible locations such as narrow areas and holes. PMID:26343667

  20. Development of a Small-Sized, Flexible, and Insertable Fiber-Optic Radiation Sensor for Gamma-Ray Spectroscopy

    Directory of Open Access Journals (Sweden)

    Wook Jae Yoo

    2015-08-01

    Full Text Available We fabricated a small-sized, flexible, and insertable fiber-optic radiation sensor (FORS that is composed of a sensing probe, a plastic optical fiber (POF, a photomultiplier tube (PMT-amplifier system, and a multichannel analyzer (MCA to obtain the energy spectra of radioactive isotopes. As an inorganic scintillator for gamma-ray spectroscopy, a cerium-doped lutetium yttrium orthosilicate (LYSO:Ce crystal was used and two solid-disc type radioactive isotopes with the same dimensions, cesium-137 (Cs-137 and cobalt-60 (Co-60, were used as gamma-ray emitters. We first determined the length of the LYSO:Ce crystal considering the absorption of charged particle energy and measured the gamma-ray energy spectra using the FORS. The experimental results demonstrated that the proposed FORS can be used to discriminate species of radioactive isotopes by measuring their inherent energy spectra, even when gamma-ray emitters are mixed. The relationship between the measured photon counts of the FORS and the radioactivity of Cs-137 was subsequently obtained. The amount of scintillating light generated from the FORS increased by increasing the radioactivity of Cs-137. Finally, the performance of the fabricated FORS according to the length and diameter of the POF was also evaluated. Based on the results of this study, it is anticipated that a novel FORS can be developed to accurately measure the gamma-ray energy spectrum in inaccessible locations such as narrow areas and holes.

  1. FaNGaS - Fast Neutron Gamma Spectroscopy instrument for prompt gamma signature of inelastic scattering reactions

    OpenAIRE

    Rossbach, Matthias; Mauerhofer, Eric

    2015-01-01

    The FaNGaS instrument has been developed and constructed at the Forschungszentrum Jülich GmbH for investigation of neutron inelastic scattering reactions using the fission neutron beam SR10 at the Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II)  operated by the Technische Universität München in Garching. Prompt emitted gamma rays from excited states of irradiated elements can be used for analytical purposes.

  2. Study of hyperfine interactions in pure and Mn-doped CeO2 nanoparticles by perturbed gamma-gamma angular perturbed spectroscopy using 111Cd and 140Ce as nuclei probe

    International Nuclear Information System (INIS)

    Full text: Cerium dioxide (CeO2) or ceria has played a crucial role in scientific research due to its extreme importance for the high-technology industry, so it has been widely studied and applied in various applications such as in automotive industry, medicine, oxygen sensors, protectors of the radiation and so on. A special case of our interest is that ceria is a good candidate to substitute SiO2 at electronic devices. In this work, a nuclear technique called Perturbed gamma-gamma Angular Correlation (PAC) was used to measure hyperfine interactions in nanostructured insulating CeO2 oxide doped with 3d transition metals that present magnetic moment. Ceria was doped with around 5 at. % Manganese (Mn), which introduce spin property for the charge carriers. It is important to remark that PAC spectroscopy uses a nuclear probe, which decays in gamma-gamma ray cascade. Here it was used 140La (140Ce) which decays through the gamma cascade 329-487 keV and 111In (111Cd) (171-245 keV) probe, both nuclear properties of the intermediate level are well known. 111Cd: t1/2 = 84.5 ns, quadrupolar moment (Q) is 0.83 b and dipolar moment μ 0.76 μN. And 140Ce: t1/2 = 3.4 ns, Q = 0.3 b and μ = 4.68 μN. Doped ceria samples were prepared by the Pechini sol-gel method from pure Ce and Mn elements. In this methodology metallic Ce and Mn are separately dissolved in nitric acid and then mixed. The obtained gel is then heated in air in a muffle furnace at 380 deg C during 10h. Radioactive probe nuclei 140La (140Ce) or 111In (111Cd) were introduced during the sample preparation. The obtained pure and doped CeO2 were annealed at 1100 deg C for 5h in N2. The PAC measurements were carried out in the temperature range from 15 K to 1175 K with a conventional slow-fast coincidence set-up with four conical Baf2 detectors. A small tubular furnace was used for heating the sample while a cryogenic system was used to cool. A comparative analysis was made for two probes nuclei used which showed that

  3. Study of radioactivity levels in detergent powders samples by gamma spectroscopy

    Directory of Open Access Journals (Sweden)

    Ali A. Abojassim

    2014-10-01

    Full Text Available This study focuses on the evaluation of the natural radioactivity levels in ten samples of the detergent powders that available in Iraqi markets. We have determined the specific activities of uranium, thorium and potassium using gamma spectroscopy and calculation of radiation hazard indices. The results of the activities of radionuclides (238U, 232Th, 40K for detergent powders samples, are found that the 238U specific activities were varied from (11.489 ± 2.089 Bq/kg to (36.062 ± 2.478 Bq/kg, while the 232th specific activities were varied from (1.411 ± 0.609 Bq/kg to (9.272 ± 1.642 Bq/kg and 40K were varied from (8.189 ± 2.339 Bq/kg to (91.888 ± 4.164 Bq/kg. These values are always lower than those of raw materials, what is explained by the conservation of radioactive material throughout the manufacturing process. The radium equivalent activity Raeq, the external hazard index Hex and the internal hazard index Hin dose due to natural radioactivity estimated below the regulatory standard recommended which are (370 Bq/kg, 1 and 1 according to OECD 1979 and ICRP 2000, allows us to show that Detergent powders samples products are not contaminated by radioactivity, are healthy and do not have harmful radiological impact on the consumer.

  4. Bridging the capability gap in in-situ and mobile gamma spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Varley, A.; Tyler, A.; Smith, L. [University of Stirling (United Kingdom); Davies, M. [NUVIA Limited (United Kingdom)

    2014-07-01

    Following its discovery at the end of the 19. Century, Radium ({sup 226}Ra and {sup 224}Ra) was quickly exploited for its radioactive properties, especially when combined with ZnS to produce luminescent paint. Radium has now become associated with contaminated land due to its extensive use by the military throughout Europe and the US during and after the 2. World War. A recent UK Government report (DECC, 2012) conservatively estimated that there are between 150-250 radium contaminated legacy sites across the UK and possibly as many as 1000. In situ and mobile gamma-ray spectroscopy has been used extensively to assay Naturally Occurring Radioactive Material (NORM) contaminated land. However, the detection of {sup 226}Ra contamination is inherently problematic, especially at depth, where spectral responses can appear very similar to background. The pattern recognition capabilities of an Artificial Neural Network (ANN) are being utilized with the aim of making contaminant identification faster. The ANN will be trained with in situ calibrated spectra and validated Monte Carlo simulations. To optimize the capabilities of an ANN, the requirement of a sensitive (high energy resolution) and high photon efficient detection system is paramount. This, up until recently, has presented a choice between the high-resolution HPGe and high-efficiency NaI detectors. Here we are exploring the latest detector technology, LaBr{sub 3}(Ce) scintillators, which offer a promising alternative. Together, this research is formulating a novel approach to improve the minimum detectable activity of {sup 226}Ra as a function of varying depth, activity and spatial distribution, whilst minimizing the effect of background. Document available in abstract form only. (authors)

  5. Development of a low noise readout ASIC for CZT detectors for gamma-ray spectroscopy applications

    International Nuclear Information System (INIS)

    A multi-channel readout ASIC for pixelated CZT detectors has been developed for gamma-ray spectroscopy applications. Each channel consists of a low noise dual-stage charge sensitive amplifier (CSA), a CR-(RC)4 semi-Gaussian shaper and a class-AB output buffer. The equivalent noise charge (ENC) of input PMOS transistor is optimized for 5 pF input capacitance and 1 μs peaking time using gm/ID design methodology. The gain can be adjusted from 100 mV/fC to 400 mV/fC and the peaking time can be adjusted from 1 μs to 4 μs. A 16-channel chip has been designed and fabricated in 0.35 μm 2P4M CMOS technology. The test results show that the chip works well and fully satisfies the design specifications. The ENC was measured to be 72 e + 26 e/pF at 1 μs peaking time and 86 e + 20 e/pF at 4 μs peaking time. The non-uniformity of the channel gain and ENC was less than ±12% and ±11% respectively for 16 channels in one chip. The chip was also tested with a pixelated CZT detector at room temperature. The measured energy resolution at 59.5 keV photopeak of 241Am and 122 keV photopeak of 57Co were 4.5% FWHM and 2.8% FWHM for the central area pixels, respectively.

  6. Gamma-ray spectrometry applied to agricultural soil in the northwest of the State of Rio de Janeiro

    International Nuclear Information System (INIS)

    The present work presents the use of gamma-ray spectrometry applied to precision agriculture in a sub-tropical area. Our dataset comprises measurements both in rock and residual soil. The soil dataset shows a reduction of 20% on U and Th and 10% on K, when compared to rock samples. This difference could be related to K supplementation associated to chemical fertilization. (author)

  7. Time-Resolved Spectroscopy of the 3 Brightest and Hardest Short Gamma-Ray Bursts Observed with the FGST Gamma-Ray Burst Monitor

    CERN Document Server

    Guiriec, Sylvain; Connaugthon, Valerie; Kara, Erin; Daigne, Frederic; Kouveliotou, Chryssa; van der Horst, Alexander J; Paciesas, William; Meegan, Charles A; Bhat, P N; Foley, Suzanne; Bissaldi, Elisabetta; Burgess, Michael; Chaplin, Vandiver; Diehl, Roland; Fishman, Gerald; Gibby, Melissa; Giles, Misty; Goldstein, Adam; Greiner, Jochen; Gruber, David; von Kienlin, Andreas; Kippen, Marc; McBreen, Sheila; Preece, Robert; Rau, Arne; Tierney, Dave; Wilson-Hodge, Colleen

    2010-01-01

    From July 2008 to October 2009, the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-ray Space Telescope (FGST) has detected 320 Gamma-Ray Bursts (GRBs). About 20% of these events are classified as short based on their T90 duration below 2 s. We present here for the first time time-resolved spectroscopy at timescales as short as 2 ms for the three brightest short GRBs observed with GBM. The time-integrated spectra of the events deviate from the Band function, indicating the existence of an additional spectral component, which can be fit by a power-law with index ~-1.5. The time-integrated Epeak values exceed 2 MeV for two of the bursts, and are well above the values observed in the brightest long GRBs. Their Epeak values and their low-energy power-law indices ({\\alpha}) confirm that short GRBs are harder than long ones. We find that short GRBs are very similar to long ones, but with light curves contracted in time and with harder spectra stretched towards higher energies. In our time-resolved spectrosco...

  8. Solved problems in analysis as applied to gamma, beta, Legendre and Bessel functions

    CERN Document Server

    Farrell, Orin J

    2013-01-01

    Nearly 200 problems, each with a detailed, worked-out solution, deal with the properties and applications of the gamma and beta functions, Legendre polynomials, and Bessel functions. The first two chapters examine gamma and beta functions, including applications to certain geometrical and physical problems such as heat-flow in a straight wire. The following two chapters treat Legendre polynomials, addressing applications to specific series expansions, steady-state heat-flow temperature distribution, gravitational potential of a circular lamina, and application of Gauss's mechanical quadrature

  9. Determination of isotopic ratios of uranium samples using passive gamma spectroscopy with multiple detectors

    International Nuclear Information System (INIS)

    Uranium samples of various enrichments have been passively counted on the University of Texas detector gamma-gamma coincidence system. By observing gamma rays emitted from 235U and its daughters compared to gamma rays emitted by 238U daughters and comparing the data to standards of known enrichments, a technique has been developed to take a uranium sample of unknown enrichment and passively count it to determine its uranium isotopic concentration. Because the gamma rays from 235U are generally in the low-energy regime, there is a strong susceptibility to background interferences, especially from the Compton background produced from higher energy gamma rays. Other interferences, such as those from the decay series of uranium also exist for 235U gamma rays. In this light, we have collected data using list-mode to produce two-dimensional gamma-gamma coincidence spectra, which allows us to gate the low-energy gamma rays from 235U with gamma rays that are in coincidence. In doing this, much of the low energy interferences are reduced, and one can analyze the 235U gamma rays with high precision. Because of the high density of uranium, self-shielding has significant effects especially in the low-energy regime. To correct for this attenuation the detector system has been modeled by MCNP and self-shielding factors have been calculated across the energy spectrum. A big advantage to this method is the capability of performing this analysis with small (<1 g) samples in a non-destructive and relatively inexpensive manner. If necessary, this analysis can be performed within 24 h if an urgent nuclear forensics scenario arises. (author)

  10. Study on Humic Acids of the Soil Applied with Corn Stalk by Spectroscopy Measurements

    Institute of Scientific and Technical Information of China (English)

    WU Jing-gui; WANG Ming-hui; JIANG Yi-mei; XU Yan

    2005-01-01

    Spectroscopy measurements (Fourier transform infrared differential spectroscopy, Carbon-13 nuclear magnetic resonance spectrometry, Matrix-assisted laser desorption/ionization-time of flight mass spectrometry) were performed to study the humic acids of the soil applied with corn stalk. The results showed that after incorporation of corn stalks into the soil, the soil humic acid (HA) changed significantly in different stages. During first 60 days, new HAs were formed by polymerization and seems to be similar to that of initial HAs from composting corn stalk, some little molecular organic matters also reacted with soil HAs and turned into parts of soil HAs. After 60 days of the corn stalk residue incorporation, new HAs were formed by polymerization of decomposed lignin molecules, some methylenes transformed into methyls and methoxyls since the 90th day. Application of corn stalk led to the increase of aliphatic components in soil HAs, the decrease in aromatic components of soil HAs and the suppression in oxidation degree of soil HAs. The average molecular weight of soil HAs also declined because of application of corn stalk.

  11. Laser induced photoacoustic spectroscopy applied to a study on coagulation processes of Tc(IV) colloid

    International Nuclear Information System (INIS)

    Quantitative determination of size and concentration of colloid particles in aqueous solutions was performed by laser induced photoacoustic spectroscopy (LPAS), and this technique was applied to a study on coagulation processes of Tc(IV) colloids. The intensity of photoacoustic signals from colloid particles (polystyrene, gold sols) was successfully calculated as a product of the number of particles and the absorption cross section per particle based on the Mie's light scattering theory. With this technique, the coagulation of Tc(IV) colloids prepared by the reduction of TcO4 with Sn(II) was observed. The observed growth rate of colloid particles was successfully analyzed by a newly developed collision model, in which both the distribution of the kinetic energy of particles and the potential barrier between the two particles played significant roles. (author)

  12. Using gamma distribution to determine half-life of rotenone, applied in freshwater

    International Nuclear Information System (INIS)

    Following the use of rotenone to eradicate invasive pest fish, a dynamic first-order kinetic model is usually used to determine the half-life and rate at which rotenone dissipated from the treated waterbody. In this study, we investigate the use of a stochastic gamma model for determining the half-life and rate at which rotenone dissipates from waterbodies. The first-order kinetic and gamma models produced similar values for the half-life (4.45 days and 5.33 days respectively) and days to complete dissipation (51.2 days and 52.48 days respectively). However, the gamma model fitted the data better and was more flexible than the first-order kinetic model, allowing us to use covariates and to predict a possible range for the half-life of rotenone. These benefits are particularly important when examining the influence that different environmental factors have on rotenone dissipation and when trying to predict the rate at which rotenone will dissipate during future operations. We therefore recommend that in future the gamma distribution model is used when calculating the half-life of rotenone in preference to the dynamic first-order kinetics model. - Highlights: • We investigated the use of the gamma model to calculate the half-life of rotenone. • Physical and environmental variables can be incorporated into the model. • A method for calculating the range around a mean half-life is presented. • The model is more flexible than the traditionally used first-order kinetic model

  13. Using gamma distribution to determine half-life of rotenone, applied in freshwater

    Energy Technology Data Exchange (ETDEWEB)

    Rohan, Maheswaran, E-mail: mrohan@aut.ac.nz [Department of Biostatistics and Epidemiology, Auckland University of Technology, Auckland (New Zealand); Fairweather, Alastair; Grainger, Natasha [Science and Capability, Department of Conservation, Hamilton (New Zealand)

    2015-09-15

    Following the use of rotenone to eradicate invasive pest fish, a dynamic first-order kinetic model is usually used to determine the half-life and rate at which rotenone dissipated from the treated waterbody. In this study, we investigate the use of a stochastic gamma model for determining the half-life and rate at which rotenone dissipates from waterbodies. The first-order kinetic and gamma models produced similar values for the half-life (4.45 days and 5.33 days respectively) and days to complete dissipation (51.2 days and 52.48 days respectively). However, the gamma model fitted the data better and was more flexible than the first-order kinetic model, allowing us to use covariates and to predict a possible range for the half-life of rotenone. These benefits are particularly important when examining the influence that different environmental factors have on rotenone dissipation and when trying to predict the rate at which rotenone will dissipate during future operations. We therefore recommend that in future the gamma distribution model is used when calculating the half-life of rotenone in preference to the dynamic first-order kinetics model. - Highlights: • We investigated the use of the gamma model to calculate the half-life of rotenone. • Physical and environmental variables can be incorporated into the model. • A method for calculating the range around a mean half-life is presented. • The model is more flexible than the traditionally used first-order kinetic model.

  14. Real time method and computer system for identifying radioactive materials from HPGe gamma-ray spectroscopy

    Science.gov (United States)

    Rowland, Mark S.; Howard, Douglas E.; Wong, James L.; Jessup, James L.; Bianchini, Greg M.; Miller, Wayne O.

    2007-10-23

    A real-time method and computer system for identifying radioactive materials which collects gamma count rates from a HPGe gamma-radiation detector to produce a high-resolution gamma-ray energy spectrum. A library of nuclear material definitions ("library definitions") is provided, with each uniquely associated with a nuclide or isotope material and each comprising at least one logic condition associated with a spectral parameter of a gamma-ray energy spectrum. The method determines whether the spectral parameters of said high-resolution gamma-ray energy spectrum satisfy all the logic conditions of any one of the library definitions, and subsequently uniquely identifies the material type as that nuclide or isotope material associated with the satisfied library definition. The method is iteratively repeated to update the spectrum and identification in real time.

  15. Analysis of coupled neutron-gamma radiations by the multigroup Albedo method applied to multilayered slab shieldings

    International Nuclear Information System (INIS)

    Full text: The principal nuclear design tools available to the shielding designer include diffusion approximation, transport theory, and Monte Carlo techniques. Full transport theory or Monte Carlo methods are routinely used for shielding analyses, where penetration investigations are more sensitive to directional aspects. However, the aim of this paper is to illustrate the coupled neutron-gamma Albedo method particularly as applied to problems of shielding analysis. The multigroup Albedo method is applied to coupled neutron-gamma radiations considering 'n' neutron energy groups and 'g' gamma energy groups to estimate the probabilities of transmission through, absorption in, and reflection from shieldings composed by multiple material layers, 'm' slabs, in which no fission occurs. In this study, these energy groups were selected in order to minimize upscattering effects of the radiation from lower energy groups to higher energy groups. However, neutrons of all energies are assumed to generate gammas of all energies. The reflection coefficient or Albedo is defined as the current of the reflected radiation divided by the incident radiation current. The absorption coefficient is defined as the rate at which radiation is lost by absorption per second divided by the amount of incident radiation per second. The transmission coefficient is defined as the current of the transmitted radiation divided by the incident radiation current. The interaction probabilities can be arranged in matrix form where the rows indicate the energy group of the incident radiation and the columns indicate the energy group of the radiation after interaction. Thus, each material has 3 sets of distinct matrices, for the interactions neutron-neutron (N-N), neutron-gamma (N-G) and gamma-gamma (G-G). Each set is composed by 3 matrices, giving a total of 9 matrices per material. The first matrix set is for scattering/downscattering of neutrons (N-N); the next set is for scattering/downscattering of

  16. [EEMD-ICA Applied in Signal Extraction in Functional Near-Infrared Spectroscopy].

    Science.gov (United States)

    Zha, Yu-tong; Liu, Guang-da; Zhou, Run-dong; Zhang, Xiao-feng; Niu, Jun-qi; Yu, Yong; Wang, Wei

    2015-10-01

    Currently, functional near-infrared spectroscopy (fNIRS) is widely used in the field of Neuroimaging. To solve the signal-noise frequency spectrum aliasing in non-linear and non-stationary fNIRS characteristic signal extraction, a new joint multi-resolution algorithm, EEMD-ICA, is proposed based on combining Independent Component Analysis with Ensemble Empirical Mode Decomposing. After functional brain imaging instrument detected the multi-channel and multi-wavelength NIR optical density signals, EEMD was performed to decompose measurement signals into multiple intrinsic mode function according to the signal frequency component. Then ICA was applied to extract the interest data from IMFs into ICs. Finally, reconstructed signals were obtained by accumulating the ICs set. EEMD-ICA was applied in de-noising Valsalva test signals which were considered as original signals and compared with Empirical Mode Decomposing and Ensemble Empirical Mode Decomposing to illustrate validity of this algorithm. It is proved that useful information loss during de-noising and invalidity of noise elimination are completely solved by EEMD-ICA. This algorithm is more optimized than other two de-noising methods in error parameters and signal-noise-ratio analysis. PMID:26904811

  17. Electro-thermal impedance spectroscopy applied to an open-cathode polymer electrolyte fuel cell

    Science.gov (United States)

    Engebretsen, Erik; Robinson, James B.; Obeisun, Oluwamayowa; Mason, Tom; Finegan, Donal; Hinds, Gareth; Shearing, Paul R.; Brett, Daniel J. L.

    2016-01-01

    The development of in-situ diagnostic techniques is critical to ensure safe and effective operation of polymer electrolyte fuel cell systems. Infrared thermal imaging is an established technique which has been extensively applied to fuel cells; however, the technique is limited to measuring surface temperatures and is prone to errors arising from emissivity variations and reflections. Here we demonstrate that electro-thermal impedance spectroscopy can be applied to enhance infrared thermal imaging and mitigate its limitations. An open-cathode polymer electrolyte fuel cell is used as a case study. The technique operates by imposing a periodic electrical stimulus to the fuel cell and measuring the consequent surface temperature response (phase and amplitude). In this way, the location of heat generation from within the component can be determined and the thermal conduction properties of the materials and structure between the point of heat generation and the point of measurement can be determined. By selectively 'locking-in' to a suitable modulation frequency, spatially resolved images of the relative amplitude between the current stimulus and temperature can be generated that provide complementary information to conventional temporal domain thermograms.

  18. A novel liquid-Xenon detector concept for combined fast-neutrons and gamma imaging and spectroscopy

    Science.gov (United States)

    Breskin, A.; Israelashvili, I.; Cortesi, M.; Arazi, L.; Shchemelinin, S.; Chechik, R.; Dangendorf, V.; Bromberger, B.; Vartsky, D.

    2012-06-01

    A new detector concept is presented for combined imaging and spectroscopy of fast-neutrons and gamma rays. It comprises a liquid-Xenon (LXe) converter and scintillator coupled to a UV-sensitive gaseous imaging photomultiplier (GPM). Radiation imaging is obtained by localization of the scintillation-light from LXe with the position-sensitive GPM. The latter comprises a cascade of Thick Gas Electron Multipliers (THGEM), where the first element is coated with a CsI UV-photocathode. We present the concept and provide first model-simulation results of the processes involved and the expected performances of a detector having a LXe-filled capillaries converter. The new detector concept has potential applications in combined fast-neutron and gamma-ray screening of hidden explosives and fissile materials with pulsed sources.

  19. Lu1-xI3:Cex--A Scintillator for gamma ray spectroscopy and time-of-flight PET

    Science.gov (United States)

    Shah, Kanai S.

    2009-03-17

    The present invention concerns very fast scintillator materials comprising lutetium iodide doped with Cerium Lu.sub.1-xI.sub.3:Ce.sub.x; LuI.sub.3:Ce). The LuI.sub.3 scintillator material has surprisingly good characteristics including high light output, high gamma ray stopping efficiency, fast response, low cost, good proportionality, and minimal afterglow that the material is useful for gamma ray spectroscopy, medical imaging, nuclear and high energy physics research, diffraction, non-destructive testing, nuclear treaty verification and safeguards, and geological exploration. The timing resolution of the scintillators of the present invention provide compositions capable of resolving the position of an annihilation event within a portion of a human body cross-section.

  20. Isotope identification of purified xenon and krypton by low- background gamma spectroscopy

    International Nuclear Information System (INIS)

    At the Nevada test site, environmental air samples are routinely analyzed for radioxenon and radiokrypton. These noble gases are separated and purified using a cryogenic gas-solid chromatography method developed by US EPA, Environmental Monitoring and Support Laboratory-Las Vegas. Each component is routinely counted by liquid scintillation. Routine counting is accomplished by liquid scintillation. Low-level gamma spectrometry is used to verify activity and/or identify isotopes present. If liquid scintillation results are observed above background, low-level gamma spectrometry identifies other gamma-emitters

  1. High-resolution gamma spectroscopy with whole-body and partial-body counters. Experience, recommendations. Report

    International Nuclear Information System (INIS)

    The application of high-resolution gamma spectroscopy with whole-body and partial-body counters shows a steadily rising upward trend over the last few years. This induced the ''Arbeitskreis Inkorporationsueberwachung'' of the association ''Fachverband fuer Strahlenschutz e.V.'' to organise a meeting for joint elaboration of a guide on recommended applications of this measuring technique, based on a review of existing experience and results. A key item on the agenda of the meeting was the comparative evaluation of the Ge semiconductor detector and the NaI solid scintillation detector. (orig./CB)

  2. Impedance Spectroscopy applied to the study of high dilutions of Lycopodium clavatum

    Directory of Open Access Journals (Sweden)

    Claudia Takano

    2011-09-01

    Full Text Available Introduction: The Impedance spectroscopy [1] is a technique mainly used to characterize the electrical behavior of solids or liquids samples. This particular technique involves placing the sample of material under investigation between two electrodes (capacitor plates, applying an AC voltage and observing the resulting response across the spectrum of impedance by plotting the real part (Z’ as a function of the imaginary part (Z” of the impedance. Alternatively, graphs of either the real or the imaginary parts of the impedance can be constructed as a function of the applied voltage frequency. Comparative measurements previously carried out by Miranda et al [2]. have demonstrated clear differences between the impedance values of high dilutions of lithium chloride (LiCl and the corresponding reference water samples (water which has undergone the same dinamization procedures but without the salt. In this paper the results obtained by applying the spectroscopy of impedance technique in high dilutions of Lycopodium clavatum - Lyc (from 15cH to 30 cH, in comparison to the reference waters, will be presented and discussed. Aims: The objective of this work is to measure the impedance components of both high dilutions of Lycopodium clavatum and reference water samples in the frequency range of 100Hz to 13Mhz, using a successful protocol of sample preparation which has already been used before2. Details of the experimental set-up can be found elsewhere[3]. Methodology: Thirty samples of Lyc solutions and thirty reference water samples were produced using the same preparation and measuring protocol. Both groups of liquid samples were measured for dynamizations ranging from 1cH to 30cH, in accordance to the Hahnemanian dynamization method and following the practice suggested by the Brazilian Homeopathic Pharmacopeia. The Lyc solutions were specifically compared to the reference water samples in the potencies of 15cH, 18c

  3. Feasibility of applying gamma irradiation as disinfestation technique on date fruits in respect to nutritional value that is affected by disinfesting gamma ray doses

    International Nuclear Information System (INIS)

    Infested and non-infested dry date fruits (Phonex dactylifera), Abrimi variety (9.2% moisture), with Ephestia cautella Walker were irradiated for 0, 15, 20 and 40 Krad gamma ray doses emitted from Co-60 source with 1.36 x 10-rad/h. as a dose rate. Irradiated fruits were stored at room temperature, at 20-250C and 85-95% R.H., in packages to avoid reinfestation. A dose of 20 Krad is 100 percent effective in preventing the emergency of eggs, larva, and pupae in fruits as reflected by zero per cent emergency count for live adults. Also, this dose was found to be lethal for adult stage of the insect. On the other hand, 2 Krad dose does not produce significant changes in the nutritional qualities of fruits, as measured by chemical analytical means for carbohydrates, protein and amino acids, directly after irradiation as well as at 2, 4 and 6 months storage. The triangular tests show that irradiation treatments even with 4 Krad exerted no determinal effect upon the sensory qualities of stored irradiated date fruits. These results point out the feasibility of applying gamma irradiation, 20 Krad, as disinfestation technique against Ephestia cautella Walker in dry date fruits without exerting any effect on the nutritional value

  4. X and low energy gamma ray spectroscopy for in vivo monitoring: technical evolution and requirements for future research

    International Nuclear Information System (INIS)

    X and low energy gamma ray spectroscopy for in-vivo monitoring: Technical evolution and requirements for future research. Whole body counting remains a major tool for individual monitoring for its fast response to assess the contamination of the lung after inhalation of radio-toxic compounds. Considering actinides such as 239Pu emitting associated X and low energy γrays, in spite of improved detection methods based on large volume germanium crystals, all investigations show detection limits much too high compared to annual limit of incorporation. Based on results obtained using germanium systems, it was shown that the improvement of lung monitoring requires the development of X spectroscopy systems with resolution comparable to germanium but operating at room temperature to allow a larger detection area better adjusted to the chest volume. Among possible materials, Si and CdTe semiconductors were identified as most promising ones. (authors)

  5. Spatial correlations applied to gamma/hadron discrimination in the ARGO-YBJ experiment

    International Nuclear Information System (INIS)

    Following recently proposed approaches on gamma/hadron separation, spatial correlations among secondary charged particles in extensive air showers have been studied for the case of the ARGO-YBJ experiment, which represents a particularly suited detector in this respect because of its “continuous-carpet” geometry. Two different types of statistics have been considered, namely the nearest-neighbor spacing distribution (NNSD) and the variance of the number of secondary particles at given distance. The results of this preliminary investigation are reported

  6. Benchmark Gamma Spectroscopy Measurements of Uranium Hexafluoride in Aluminmum Pipe with a Sodium Iodide Detector

    Energy Technology Data Exchange (ETDEWEB)

    March-Leuba, Jose A [ORNL; Uckan, Taner [ORNL; Gunning, John E [ORNL; Brukiewa, Patrick D [ORNL; Upadhyaya, Belle R [ORNL; Revis, Stephen M [ORNL

    2010-01-01

    The expected increased demand in fuel for nuclear power plants, combined with the fact that a significant portion of the current supply from the blend down of weapons-source material will soon be coming to an end, has led to the need for new sources of enriched uranium for nuclear fuel. As a result, a number of countries have announced plans, or are currently building, gaseous centrifuge enrichment plants (GCEPs) to supply this material. GCEPs have the potential to produce uranium at enrichments above the level necessary for nuclear fuel purposes-enrichments that make the uranium potentially usable for nuclear weapons. As a result, there is a critical need to monitor these facilities to ensure that nuclear material is not inappropriately enriched or diverted for unintended use. Significant advances have been made in instrument capability since the current International Atomic Energy Agency (IAEA) monitoring methods were developed. In numerous cases, advances have been made in other fields that have the potential, with modest development, to be applied in safeguards applications at enrichment facilities. A particular example of one of these advances is the flow and enrichment monitor (FEMO). (See Gunning, J. E. et al., 'FEMO: A Flow and Enrichment Monitor for Verifying Compliance with International Safeguards Requirements at a Gas Centrifuge Enrichment Facility,' Proceedings of the 8th International Conference on Facility Operations - Safeguards Interface. Portland, Oregon, March 30-April 4th, 2008.) The FEMO is a conceptual instrument capable of continuously measuring, unattended, the enrichment and mass flow of {sup 235}U in pipes at a GCEP, and consequently increase the probability that the potential production of HEU and/or diversion of fissile material will be detected. The FEMO requires no piping penetrations and can be installed on pipes containing the flow of uranium hexafluoride (UF{sub 6}) at a GCEP. This FEMO consists of separate parts, a flow

  7. Combined Electric, Electromagnetic and Gamma Spectrometric Methods Applied to the Pariquera-Açu Alkaline Complex

    Directory of Open Access Journals (Sweden)

    Elaine Maria Lopes Loureiro

    2011-08-01

    Full Text Available The Pariquera-Açu Alkaline Complex, located in the city of Pariquera-Açu (State of São Paulo, is one of the Brazilianalkaline complexes which has considerable mining potential. The combined use of several methods helped to determinepossible areas for exploration. Geophysical prospecting methods were used to assess the exploration potential of theseareas. The methods used in this study were gamma-spectrometry, induced polarization and electrical survey. Previousgeophysical studies were carried out to better understand the structural evolution of the complex and were not limited tothe study of the lithological variation. Gravimetric studies showed a zone of intense fenitization, which is consistent withalkaline complexes with carbonatites. A dipole-dipole survey conducted in the central part of the complex indicated thepresence in the subsurface of a resistive lithology with high chargeability. These factors, together with other studies onthe alkaline complex, suggest the presence of carbonatite in the area, which is corroborated by gamma spectrometry data,given the concentrations of Th (8 ppm and U (3.5 ppm and considering that the measurements were performed over a nonradioactivesedimentary cover.

  8. Double pulse laser induced breakdown spectroscopy applied to natural and artificial materials from cultural heritages

    International Nuclear Information System (INIS)

    The laser-induced breakdown spectroscopy (LIBS) is an applied physical technique that has shown in recent years its great potential for rapid qualitative analysis of materials. Thanks to the possibility to implement a portable instrument that perform LIBS analysis, this technique is revealed to be particularly useful for in situ analysis in the field of cultural heritages. The purpose of this work is to evaluate the potentiality of LIBS technique in the field of cultural heritages, with respect to the chemical characterization of complex matrix as calcareous and refractory materials for further quantitative analyses on cultural heritages. X-Ray Fluorescence (XRF) analyses were used as reference. Calibration curves of certified materials used as standards were obtained by XRF analyses. The LIBS measurements were performed with a new mobile instrument called Modi (Mobile Double pulse Instrument for LIBS Analysis). The XRF analyses were performed with a portable instrument ArtTAX. LIBS and XRF measurement were performed on both reference materials and samples (bricks and mortars) sampled in the ancient Greek-Roman Theatre of Taormina. Although LIBS measurements performed on reference materials have shown non linear response to concentrations, and so we were not able to obtain quantitative results, an integrated study of XRF and LIBS signals permitted us to distinguish among chemical features and degradation state of measured building materials.

  9. Double pulse laser induced breakdown spectroscopy applied to natural and artificial materials from cultural heritages

    Energy Technology Data Exchange (ETDEWEB)

    Brai, Maria; Gennaro, Gaetano [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze Ed.18, 90128 Palermo (Italy); Schillaci, Tiziano, E-mail: tschillaci@unipa.i [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze Ed.18, 90128 Palermo (Italy); Tranchina, Luigi [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze Ed.18, 90128 Palermo (Italy)

    2009-10-15

    The laser-induced breakdown spectroscopy (LIBS) is an applied physical technique that has shown in recent years its great potential for rapid qualitative analysis of materials. Thanks to the possibility to implement a portable instrument that perform LIBS analysis, this technique is revealed to be particularly useful for in situ analysis in the field of cultural heritages. The purpose of this work is to evaluate the potentiality of LIBS technique in the field of cultural heritages, with respect to the chemical characterization of complex matrix as calcareous and refractory materials for further quantitative analyses on cultural heritages. X-Ray Fluorescence (XRF) analyses were used as reference. Calibration curves of certified materials used as standards were obtained by XRF analyses. The LIBS measurements were performed with a new mobile instrument called Modi (Mobile Double pulse Instrument for LIBS Analysis). The XRF analyses were performed with a portable instrument ArtTAX. LIBS and XRF measurement were performed on both reference materials and samples (bricks and mortars) sampled in the ancient Greek-Roman Theatre of Taormina. Although LIBS measurements performed on reference materials have shown non linear response to concentrations, and so we were not able to obtain quantitative results, an integrated study of XRF and LIBS signals permitted us to distinguish among chemical features and degradation state of measured building materials.

  10. Application of gamma-ray spectroscopy to the differentiation between mobile and deposited fission products in pipes

    International Nuclear Information System (INIS)

    A method has been developed to differentiate between material flowing in pipes and deposited on the pipe walls. This has been applied to a study of fission product release from irradiated fuel under severe accident conditions. A collimation arrangement has been examined which provides good discrimination between gamma- radiation arising from flowing gases/aerosols and from stationary deposits. A systematic examination has been made of gamma- radiation obtained from gases and deposits in pipes of different diameter for a number of collimator configurations. A system of calibration has been developed based on Monte-Carlo modelling which has been found to be in broad agreement with measured values. This knowledge has been applied to the data obtained in a real-time measurement undertaken on the FALCON reactor safety facility at AEA Technology, Winfrith

  11. Transmission and signal loss in mask designs for a dual neutron and gamma imager applied to mobile standoff detection

    International Nuclear Information System (INIS)

    In order to design a next-generation, dual neutron and gamma imager for mobile standoff detection which uses coded aperture imaging as its primary detection modality, the following design parameters have been investigated for gamma and neutron radiation incident upon a hybrid, coded mask: (1) transmission through mask elements for various mask materials and thicknesses; and (2) signal attenuation in the mask versus angle of incidence. Each of these parameters directly affects detection significance, as quantified by the signal-to-noise ratio. The hybrid mask consists of two or three layers: organic material for fast neutron attenuation and scattering, Cd for slow neutron absorption (if applied), and one of three of the following photon or photon and slow neutron attenuating materials—Linotype alloy, CLYC, or CZT. In the MCNP model, a line source of gamma rays (100–2500 keV), fast neutrons (1000–10,000 keV) or thermal neutrons was positioned above the hybrid mask. The radiation penetrating the mask was simply tallied at the surface of an ideal detector, which was located below the surface of the last mask layer. The transmission was calculated as the ratio of the particles transmitted through the fixed aperture to the particles passing through the closed mask. In order to determine the performance of the mask considering relative motion between the source and detector, simulations were used to calculate the signal attenuation for incident radiation angles of 0 50°. The results showed that a hybrid mask can be designed to sufficiently reduce both transmission through the mask and signal loss at large angles of incidence, considering both gamma ray and fast neutron radiations. With properly selected material thicknesses, the signal loss of a hybrid mask, which is necessarily thicker than the mask required for either single mode imaging, is not a setback to the system's detection significance

  12. Study on sodium viewing technique applying sodium gamma-rays emission tomography. Verification of basic principle by analytical investigation

    International Nuclear Information System (INIS)

    To confirm structural integrity of a primary cooling system and in-vessel components in a sodium-cooled fast breeder reactor, monitoring and inspection technique applying Gamma-rays emitted from sodium are proposed. The basic principle is as follows. As radioisotope 24Na decays, photons are emitted and a fraction of these photons penetrate materials. If the number of these photons is counted by radiation detectors, an image of gamma-rays source is reconstructed by a computed tomography technique. In this report, Applicability and problems concerned with the technique are investigated. Main results are as follows: (1) To verify applicability, the technique was analytically investigated based on gamma-rays emitted from sodium coolant in a typical pipe of a primary cooling system. As a result, it was confirmed that the image of gamma-rays source could be reconstructed. (2) A required time to measure in a spatial resolution of about 1mm was investigated in the detection efficiency of 20%. The time was about 4 minutes per section by a thousand detectors in the typical pipe of a primary cooling system. And in a typical steam generator, the time was about 2 days per section by ten thousand detectors. (3) To realize a fluoroscopic inspection system, it is necessary that the principle should be verified by experimental researches. Main equipments of the system are a collimator, radiation detector, scanner, signal processing device and image processing device. As a spatial resolution is decide by the collimator, the shape must be evaluated by experimental researches and analytical investigation. (author)

  13. Radioactive Waste Characterization Strategies; Comparisons Between AK/PK, Dose to Curie Modeling, Gamma Spectroscopy, and Laboratory Analysis Methods- 12194

    International Nuclear Information System (INIS)

    In the coming fiscal years of potentially declining budgets, Department of Energy facilities such as the Los Alamos National Laboratory (LANL) will be looking to reduce the cost of radioactive waste characterization, management, and disposal processes. At the core of this cost reduction process will be choosing the most cost effective, efficient, and accurate methods of radioactive waste characterization. Central to every radioactive waste management program is an effective and accurate waste characterization program. Choosing between methods can determine what is classified as low level radioactive waste (LLRW), transuranic waste (TRU), waste that can be disposed of under an Authorized Release Limit (ARL), industrial waste, and waste that can be disposed of in municipal landfills. The cost benefits of an accurate radioactive waste characterization program cannot be overstated. In addition, inaccurate radioactive waste characterization of radioactive waste can result in the incorrect classification of radioactive waste leading to higher disposal costs, Department of Transportation (DOT) violations, Notice of Violations (NOVs) from Federal and State regulatory agencies, waste rejection from disposal facilities, loss of operational capabilities, and loss of disposal options. Any one of these events could result in the program that mischaracterized the waste losing its ability to perform it primary operational mission. Generators that produce radioactive waste have four characterization strategies at their disposal: - Acceptable Knowledge/Process Knowledge (AK/PK); - Indirect characterization using a software application or other dose to curie methodologies; - Non-Destructive Analysis (NDA) tools such as gamma spectroscopy; - Direct sampling (e.g. grab samples or Surface Contaminated Object smears) and laboratory analytical; Each method has specific advantages and disadvantages. This paper will evaluate each method detailing those advantages and disadvantages

  14. Gamma ray tracking with the AGATA demonstrator. A novel approach for in-beam spectroscopy

    International Nuclear Information System (INIS)

    The Advanced GAmma Tracking Array (AGATA) employs the novel method of γ-ray tracking (GRT), where all locations of energy depositions within the Ge crystal detector volume are used by computer algorithms to reconstruct the various simultaneous interactions of the measured radiation. The interaction positions are determined by Pulse Shape Analysis (PSA) algorithms that compare the measured and digitized signals with the information of a signal database comprising position dependent calculated sets of detector signals. The result of a detailed comparison between measured and calculated signals yields the position of each interaction point. The GRT algorithms rely on this precise position of the deposited energy as an input to reconstruct the initial γ-rays from the full sequence of the different interactions in the detector. Within this thesis a computer program library was developed, providing software routines to calculate the position dependent detector signals of the highly segmented HPGe detectors. The currently used signal databases of all AGATA detectors were generated by this software package and computer library. Part of the computing is based on individual detector properties which were deduced from detailed characterisation measurements. Details of the library, the used routines and the needed characteristics of the detector system are described, this includes a precise measurement of the crystal axis orientation of the AGATA HPGe crystals. The second part of this thesis is dealing with the analysis of one of the first in-beam experiments performed with the AGATA demonstrator setup at the LNL in Italy. The experiment aimed for a spectroscopic investigation of neutron rich actinides from Thorium to Plutonium produced after multi-nucleon transfer reactions. For this purpose a 136Xe beam with an energy of 1 GeV bombarded onto a 238U target. The fast beam like particles after the transfer reactions were identified by the magnetic spectrometer PRISMA. The

  15. Advanced performance and scalability of Si nanowire field-effect transistors analyzed using noise spectroscopy and gamma radiation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.; Vitusevich, S. A., E-mail: s.vitusevich@fz-juelich.de; Pud, S.; Offenhäusser, A. [Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich (Germany); Petrychuk, M. V. [Radiophysics Faculty, Shevchenko National University, Kiev (Ukraine); Danilchenko, B. A. [Institute of Physics, NASU, Kiev (Ukraine)

    2013-11-28

    High-quality Si nanowire field effect transistors (FETs) were fabricated using thermal nanoimprint and chemical wet etching technologies. FET structures of different lengths demonstrate high carrier mobility with values of about 750 cm{sup 2}/Vs and low volume densities of active traps in the dielectric layers of 5 × 10{sup 17} cm{sup −3} eV{sup −1}. We investigated the transport properties of these n-type channel structures using low-frequency noise spectroscopy before and after gamma radiation treatment. Before gamma irradiation, FET structures with lengths of less than 4 μm exhibited noise from contact regions with 1/(L{sup 2}) dependence for the relative 1/f noise. After gamma radiation, the spectra reflected the priority of channel noise with 1/L dependence for all samples. The transport characteristics show that the fabricated nanowire FETs improved scalability, decreased parameter scattering, and increased stability after treatment. The results demonstrate that these nanowire FETs are promising for nanoelectronic and biosensor applications due to the cost-efficient technology and advanced performance of FETs with improved stability and reliability.

  16. Spectroscopy of few-particle nuclei around magic {sup 132}Sn from fission product {gamma}-ray studies.

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, C. T.

    1998-07-29

    We are studying the yrast structure of very neutron-rich nuclei around doubly magic {sup 132}Sn by analyzing fission product {gamma}-ray data from a {sup 248}Cm source at Eurogam II. Yrast cascades in several few-valence-particle nuclei have been identified through {gamma}{gamma} cross coincidences with their complementary fission partners. Results for two-valence-particle nuclei {sup 132}Sb, {sup 134}Te, {sup 134}Sb and {sup 134}Sn provide empirical nucleon-nucleon interactions which, combined with single-particle energies already known in the one-particle nuclei, are essential for shell-model analysis in this region. Findings for the N = 82 nuclei {sup 134}Te and {sup 135}I have now been extended to the four-proton nucleus {sup 136}Xe. Results for the two-neutron nucleus {sup 134}Sn and the N = 83 isotones {sup 134}Sb, {sup 135}Te and {sup 135}I open up the spectroscopy of nuclei in the northeast quadrant above {sup 132}Sn.

  17. The Music of the Stars : Spectroscopy of Pulsations in gamma Doradus Stars

    Science.gov (United States)

    Brunsden, Emily

    2013-05-01

    p>The mysteries of the interior structures of stars are being tackled with asteroseismology. The observable parameters of the surface pulsations of stars inform us of the interior characteristics of numerous classes of stars. The main-sequence gamma Doradus stars, just a little hotter than the Sun, offer the potential of determining stellar structure right down to the core. To determine the structural profile of a star, the observed frequencies and a full geometric description must be determined. This is only possible with long-term spectroscopic monitoring and careful analysis of the pulsation signature in spectral lines. This work seeks to identify the pulsational geometry of several gamma Doradus stars and to identify areas of improvement for current observation, analysis and modelling techniques. More than 4500 spectra were gathered on five stars for this purpose. For three stars a successful multi-frequency and mode identification solution was determined and significant progress has been made towards the understanding of a binary system involving a gamma Doradus star. A hybrid gamma Doradus/nbsp;delta Scuti pulsator was also intensely monitored and results from this work raise important questions about the classification of this type of star. Current analysis techniques were found to be fit-for-purpose for pure gamma Doradus stars, but stars with complexities such as hybrid pulsations and/or fast rotation require future development of the current models./p>

  18. Feasibility study of performing high precision gamma spectroscopy of {lambda}{lambda} hypernuclei in the anti PANDA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Lorente, Alicia

    2010-09-30

    Hypernuclear research will be one of the main topics addressed by the anti PANDA experiment at the planned Facility for Antiproton and Ion Research anti FAIR. Thanks to the use of stored anti p beams, copious production of double {lambda} hypernuclei is expected at the anti PANDA experiment, which will enable high precision {gamma} spectroscopy of such nuclei for the first time. At anti PANDA excited states of {xi}{sup -} hypernuclei will be used as a basis for the formation of double {lambda} hypernuclei. For their detection, a devoted hypernuclear detector setup is planned. This setup consists of a primary nuclear target for the production of {xi}{sup -}+ anti {xi} pairs, a secondary active target for the hypernuclei formation and the identification of associated decay products and a germanium array detector to perform {gamma} spectroscopy. In the present work, the feasibility of performing high precision {gamma} spectroscopy of double {lambda} hypernuclei at the anti PANDA experiment has been studied by means of a Monte Carlo simulation. For this issue, the designing and simulation of the devoted detector setup as well as of the mechanism to produce double {lambda} hypernuclei have been optimized together with the performance of the whole system. In addition, the production yields of double hypernuclei in excitedparticle stable states have been evaluated within a statistical decay model. A strategy for the unique assignment of various newly observed {gamma}-transitions to specific double hypernuclei has been successfully implemented by combining the predicted energy spectra of each target with the measurement of two pion momenta from the subsequent weak decays of a double hypernucleus. Indeed, based on these Monte Carlo simulation, the analysis of the statistical decay of {sup 13}{sub {lambda}}{sub {lambda}}B has been performed. As result, three {gamma}-transitions associated to the double hypernuclei {sup 11}{sub {lambda}}{sub {lambda}}Be and to the single

  19. A gamma-ray therapeutic system applied to treatment of body tumors

    Institute of Scientific and Technical Information of China (English)

    HUANG Yu; DUAN Zheng-Cheng; ZHU Guo-Li; GONG Shi-Hua; LI Xiao-Ping

    2004-01-01

    In order to treat malignant tumors in human body, a stereotactic gamma-ray whole-body therapeutic system has been developed. This system is a typical large mechatronics treatment machine. In this paper, its main working principles and characteristics are introduced. This system comprises a special gallows frame with an open vertical structure, a changeable collimator device by which the size of convergence center can be chosen, and a 3D treatment couch. A computer brings the couch to target position automatically. Therefore precise and dynamic rotary converging therapy for tumors located anywhere in the body has been realized. The system's performance has been proved in practice, which includes good curative effect, reliable automation, and safe and secure operation.

  20. Studies of P(VDF-HFP) copolymer applied to gamma dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Liz, Otavio S.R.; Medeiros, Adriana S. [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Faria, Luiz O., E-mail: farialo@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    When polymeric materials are irradiated by ionizing radiation, the effects are roughly divided into two types, degradation (chain scission) and chain link (crosslinking). These effects are normally identified by spectroscopic analysis in the UV-Vis and Infrared region. Recently, the intensities of optical absorption in the ultraviolet visible region (273 nm) due to radio-induction of conjugated C = C bonds in P(VDF-TrFE) copolymers have been successfully used for high dose gamma dosimetry, for doses ranging from 0.1 to 200 kGy. In this context, there is now an interest to conduct a similar systematic investigation of another fluorinated copolymer of PVDF, the poly(fluorovinylidene-co-hexafluoropropylene) [P(VDF-HFP)], not only in the UV-VIS region but also in the near and mid-infrared region. The copolymer used was obtained by randomly adding 10% molar of [CF2- CF-CF3] monomers in the [CH2-CF2]n main chain of PVDF homopolymer. Preliminary results have shown that the irradiated copolymer has characteristic absorption bands originated by irradiation in the FTIR spectrum. It was found that the 1852 cm{sup -1} band, associated with C = O bonds, have a linear correlation with the absorbed dose for doses ranging from 10 to 750 kGy. The absorption band at 1729 cm{sup -1}, associated to chain oxidation (C = O), has shown a similar behavior and can be used to measure doses from 100 to 1000 kGy. These results indicate that the FTIR absorption bands of gamma irradiated P (VDF-HFP) have great potential to be used in high dose dosimetry, without the addition of dyes. (author)

  1. Study of dynamic behavior of EDTA molecule in solution using perturbed gamma-gamma angular correlation spectroscopy

    International Nuclear Information System (INIS)

    In this work, PAC spectroscopy has been used to obtain the hyperfine parameters in EDTA molecules in solutions with pH 4.3 and pH 10.5 both measured at 77 K and 295 K using 181Hf(181Ta) as probe nuclei. Both dynamic and static interactions were measured in aqueous solution, crystallized and re-hydrated samples in order to examine the motion and structure of EDTA-molecules. The hyperfine parameters, quadrupole interaction frequency (νQ), asymmetry (η), and the dynamic interaction frequency (λ) were obtained. The outcomes show that the rotational correlation time (τCR) is larger than the half-life of the intermediate state of probe nuclei. For samples with pH 4.3 and pH 10.5, it was observed an increase in νQ when the temperature decreases, as expected, and also a variation of η, which is an evidence of a change in the EDTA molecule structure. 181Hf is bound only to a single molecule site when the pH was 4.3, differently from the results for pH 10.5 sample, which showed two fractions with different νQ indicating the possibility of 181Hf being bonded to two different sites of the molecule. Measurements of the dehydrated sample presented different results leading us to conclude that the preparation procedure can causes alterations in the chemical bounds. Concluding, these results showed a systematic behavior of the 181Hf-EDTA, with the variation of pH from 4 to approximately 11, and they are important to the knowledge of the dynamic behavior of this molecule. (author)

  2. Gamma/neutron dose evaluation using Fricke gel and alanine gel dosimeters to be applied in boron neutron capture therapy

    International Nuclear Information System (INIS)

    Full text: Radiosurgery is a non-invasive surgery carried out by means of directed beams of ionizing radiation. This procedure was developed since there are many diseases for which conventional surgical treatment can not be applied, due to difficult or vital structures being damaged. Neutron radiation from nuclear reactors is used in a kind of radiosurgery called Boron Neutron Capture Therapy (BNCT) for the treatment of brain tumours which depends on the interaction of slow neutrons with 10B isotope injected in the tumour to produce alpha particles. Gel Dosimetry allows three-dimensional (3D) measurement of absorbed dose in tissueequivalent dosimeter phantoms. The measure technique is based on the transformation of ferrous ions (Fe2+) and ferric ions (Fe3+). The ferric ions concentration can be measured by spectrophotometry technique comparing the two wavelengths, 457 nm band that corresponds to ferrous ions concentration and 588 nm band that corresponds to ferric ions concentration. This work aims to study the gamma/neutron reactor dose relationship to be applied in BNCT using gel dosimeters. The Fricke Xylenol Gel (FXG) and Alanine Gel (AG) gel solutions produced at IPEN using gelatine 300 bloom were mixed with Na2B4O7 salt containing 19,9% of 10B isotope. This solutions were used to evaluate thermal and epithermal neutrons and gamma doses at an irradiation cell on BH3 of the IEA-R1 research reactor of IPEN

  3. Chemometric methods and near-infrared spectroscopy applied to bioenergy production

    International Nuclear Information System (INIS)

    The present work examines bioenergy production from different viewpoints. The three main objectives are: (1) to reveal the relation of technology, sustainability and economy in bioenergy processes; (2) to investigate spectroscopic methods as a tool for analytical monitoring of bioenergy processes; and (3) to develop new chemometric methods for advanced analysis of spectroscopic data. At the first stage, this thesis investigates the technological, ecological, and economic features of renewable-resource-based and de-centralized bioenergy production systems. In different scenarios, small-scale bioethanol production is combined with other technologies that provide renewable energy from residuals of the bioethanol process. The general aim is to substitute fossil energy conventionally used within the bioethanol process. The investigated technologies are biogas production and straw incineration. Agricultural aspects are introduced by sustainable crop rotation concepts that reconcile food, feed, and biofuel production. The sustainability of small-scale bioethanol production in the different scenarios is quantified by an ecological footprint method, the sustainable process index, SPI, and compared to conventional fuels. The main findings are: (i) small-scaled bioethanol production can be operated with 100 % renewable energy supply, (ii) the SPI of bioethanol can be reduced up to 92 % compared to conventional fuels, (iii) a complex trade-off between ecology-of-scale and economy-of-scale is necessary. At the second stage, this thesis approaches bioenergy production processes from an analytical perspective, and presents near-infrared spectroscopy (NIR) as promising method for fast process monitoring of bioethanol production and biomass characterization. In addition, new analytical methods are presented for a fast determination of the heating value of solid biomass fuel, based on IR and NIR spectroscopy. The main findings are that NIR spectroscopy and appropriate chemometric

  4. Gamma-ray spectroscopy and pulse shape discrimination with a plastic scintillator

    International Nuclear Information System (INIS)

    The scintillation properties of a novel plastic scintillator loaded with an organolead compound are presented. Under X-ray and gamma-ray excitation, emission is observed peaking at 435 nm. The scintillation light output is 9000 ph/MeV. An energy resolution (full width at half maximum over the peak position) of about 16% was observed for the 662 keV full absorption peak. Excellent pulse shape discrimination between neutrons and gamma-rays with a Figure of Merit of 2.6 at 1 MeVee was observed

  5. FTIR spectroscopy as an alternative tool for high gamma dose dosimetry using P(VDF-TrFE) fluorinated copolymers

    International Nuclear Information System (INIS)

    Poly(vinylidene fluoride) [PVDF] is a semicrystalline homopolymer and some of its fluorinated copolymer has demonstrated to have sensitiveness to high doses of ionizing radiation. We have recently proposed a semicrystalline fluorinated PVDF copolymer, the poly(vinylidene-trifluorethylene) [P(VDF-TrFE], as a candidate for measuring larger dose ranges. In fact, in these copolymers the optical absorption peak at 274 nm has been used to measure gamma doses ranging from 1.0 to 100.0 kGy and the melting latent heat, collected by differential scanning calorimetry (DSC), have been used to measure gamma doses from 1.0 to 1,000.0 kGy. In this paper, the infrared stretching vibration of radio-induced in-chain unsaturations (CH=CF) in P(VDF-TrFE) copolymers has been considered as an alternative tool for high dose dosimetric purposes. FTIR spectroscopic data revealed two optical absorption bands at 1754 cm-1 and 1854 cm-1 whose intensities are unambiguously related to gamma delivered doses ranging from 100.0 kGy to 1,000.0 kGy. Fading was evaluated one month after irradiation. The results indicate that the sample dose evaluation should be performed in the first two hours after being exposed to the radiation beam. The radio-induced formation of unsaturations was also investigated by ultraviolet and visible spectroscopy, which has confirmed the gradual increase of conjugated C=C bonds with the absorbed dose. Our results indicate that quantitative analysis of FTIR absorption bands is a useful tool to perform a product end-point dosimetry in radiation processing facilities that use high gamma dose irradiation. (author)

  6. Development of a detector based on Silicon Drift Detectors for gamma-ray spectroscopy and imaging applications

    International Nuclear Information System (INIS)

    This work deals with the development of a new gamma detector based on Silicon Drift Detectors (SDDs) to readout large LaBr3:Ce scintillators for gamma-ray spectroscopy and imaging applications. The research is supported by the European Space Agency through the Technology Research Programme (TRP) and by Istituto Nazionale di Fisica Nucleare (INFN) within the Gamma project. The SDDs, produced at Fondazione Bruno Kessler (FBK) semiconductor laboratories, are designed as monolithic arrays of 3 × 3 units, each one of an active area of 8 mm × 8 mm (overall area of 26 mm × 26 mm). The readout electronics and the architecture of the camera are briefly described and then first experimental results coupling the SDD array with a 1'' × 1'' LaBr3:Ce scintillator are reported. An energy resolution of 3% FWHM at 662 keV has been measured at -20°C, better than coupling the same scintillator with a photomultiplier tube. The same scintillator is also used to evaluate position sensitivity with a 1 mm collimated Cs-137 source. The main difficulty in determining the position of the gamma-ray interaction in the crystal is associated to the high thickness/diameter ratio of the crystal (1:1) and the use of reflectors on all lateral and top sides the crystal. This last choice enhances energy resolution but makes imaging capability more challenging because light is spread over all photodetectors. Preliminary results show that the camera is able to detect shifts in the measured signals, when the source is moved with steps of 5 mm. A modified version of the centroid method is finally implemented to evaluate the imaging capability of the system

  7. Development of a detector based on Silicon Drift Detectors for gamma-ray spectroscopy and imaging applications

    Science.gov (United States)

    Busca, P.; Butt, A. D.; Fiorini, C.; Marone, A.; Occhipinti, M.; Peloso, R.; Quaglia, R.; Bombelli, L.; Giacomini, G.; Piemonte, C.; Camera, F.; Giaz, A.; Million, B.; Nelms, N.; Shortt, B.

    2014-05-01

    This work deals with the development of a new gamma detector based on Silicon Drift Detectors (SDDs) to readout large LaBr3:Ce scintillators for gamma-ray spectroscopy and imaging applications. The research is supported by the European Space Agency through the Technology Research Programme (TRP) and by Istituto Nazionale di Fisica Nucleare (INFN) within the Gamma project. The SDDs, produced at Fondazione Bruno Kessler (FBK) semiconductor laboratories, are designed as monolithic arrays of 3 × 3 units, each one of an active area of 8 mm × 8 mm (overall area of 26 mm × 26 mm). The readout electronics and the architecture of the camera are briefly described and then first experimental results coupling the SDD array with a 1'' × 1'' LaBr3:Ce scintillator are reported. An energy resolution of 3% FWHM at 662 keV has been measured at -20°C, better than coupling the same scintillator with a photomultiplier tube. The same scintillator is also used to evaluate position sensitivity with a 1 mm collimated Cs-137 source. The main difficulty in determining the position of the gamma-ray interaction in the crystal is associated to the high thickness/diameter ratio of the crystal (1:1) and the use of reflectors on all lateral and top sides the crystal. This last choice enhances energy resolution but makes imaging capability more challenging because light is spread over all photodetectors. Preliminary results show that the camera is able to detect shifts in the measured signals, when the source is moved with steps of 5 mm. A modified version of the centroid method is finally implemented to evaluate the imaging capability of the system.

  8. Signal enhancement in collinear double-pulse laser-induced breakdown spectroscopy applied to different soils

    International Nuclear Information System (INIS)

    Laser-induced breakdown spectroscopy (LIBS) is a well-known consolidated analytical technique employed successfully for the qualitative and quantitative analysis of solid, liquid, gaseous and aerosol samples of very different nature and origin. Several techniques, such as dual-pulse excitation setup, have been used in order to improve LIBS's sensitivity. The purpose of this paper was to optimize the key parameters as excitation wavelength, delay time and interpulse, that influence the double pulse (DP) LIBS technique in the collinear beam geometry when applied to the analysis at atmospheric air pressure of soil samples of different origin and texture from extreme regions of Brazil. Additionally, a comparative study between conventional single pulse (SP) LIBS and DP LIBS was performed. An optimization of DP LIBS system, choosing the correct delay time between the two pulses, was performed allowing its use for different soil types and the use of different emission lines. In general, the collinear DP LIBS system improved the analytical performances of the technique by enhancing the intensity of emission lines of some elements up to about 5 times, when compared with conventional SP-LIBS, and reduced the continuum emission. Further, the IR laser provided the best performance in re-heating the plasma. - Highlights: • The correct choice of the delay time between the two pulses is crucial for the DP system. • An optimization of DP LIBS system was performed allowing its use for different soil and the use of different emission lines. • The DP LIBS system improved the analytical performances of the technique up to about 5 times, when compared with SP LIBS. • The IR laser provided the best performance in re-heating the plasma

  9. A new method in gamma-ray spectroscopy: A two crystal scintillation spectrometer with improved resolution

    NARCIS (Netherlands)

    Hoogenboom, A.M.

    1958-01-01

    A new method has been developed to measure the spectra of gamma radiation emitted in cascade disintegrations. Use is made of a two-crystal scintillation spectrometer and a gated multi-channel analysing device. The pulses produced by summing the outputs of the two crystal-photomultiplier combinations

  10. A preliminary intercomparison of gamma-ray spectroscopy on building materials

    NARCIS (Netherlands)

    Anagnostakis, M.J.; Bolzan, C.; De Felice, P.; Fazio, A.; Grisanti, G.; Risica, S.; Turtiainen, T.; van der Graaf, E.R.

    2004-01-01

    A preliminary intercomparison on gamma-ray spectrometry determination of natural radionuclides in building materials was carried out in 1999-2002. Samples measured were fly ash, sand and tuff. Laboratories used different experimental equipment and procedures. Corrections for blank, spectral interfer

  11. Dust extinction in high-z galaxies with gamma-ray burst afterglow spectroscopy

    DEFF Research Database (Denmark)

    Elíasdóttir, Á.; Fynbo, J. P. U.; Hjorth, J.;

    2009-01-01

    We report the clear detection of the 2175 Å dust absorption feature in the optical afterglow spectrum of the gamma-ray burst (GRB) GRB 070802 at a redshift of z = 2.45. This is the highest redshift for a detected 2175 Å dust bump to date, and it is the first clear detection of the 2175 Å bump in ...

  12. Delayed Gamma-Ray Spectroscopy for Non-Destructive Assay of Nuclear Materials

    Energy Technology Data Exchange (ETDEWEB)

    Ludewigt, Bernhard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mozin, Vladimir [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Campbell, Luke [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Favalli, Andrea [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hunt, Alan W. [Iowa State Univ., Ames, IA (United States); Reedy, Edward T.E. [Iowa State Univ., Ames, IA (United States); Seipel, Heather A. [Iowa State Univ., Ames, IA (United States)

    2015-09-28

    This project has been a collaborative effort of researchers from four National Laboratories, Lawrence Berkley National Laboratory (LBNL), Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Pacific Northwest National Laboratory (PNNL), and Idaho State University’s (ISU) Idaho Accelerator Center (IAC). Experimental measurements at the Oregon State University (OSU) were also supported. The research included two key components, a strong experimental campaign to characterize the delayed gamma-ray signatures of the isotopes of interests and of combined targets, and a closely linked modeling effort to assess system designs and applications. Experimental measurements were performed to evaluate fission fragment yields, to test methods for determining isotopic fractions, and to benchmark the modeling code package. Detailed signature knowledge is essential for analyzing the capabilities of the delayed gamma technique, optimizing measurement parameters, and specifying neutron source and gamma-ray detection system requirements. The research was divided into three tasks: experimental measurements, characterization of fission yields, and development of analysis methods (task 1), modeling in support of experiment design and analysis and for the assessment of applications (task 2), and high-rate gamma-ray detector studies (task 3).

  13. $\\beta$3p- spectroscopy and P-$\\gamma$ width determination in the decay of $^{31}$Ar

    CERN Multimedia

    We propose to perform a detailed study of the $\\beta$-decay of the dripline nucleus $^{31}$Ar. This will allow a detailed study of the $\\beta$-delayed 3p-decay as well as provide important information on the resonances of $^{30}$S and $^{29}$P, in particular the ratio between the P- and $\\gamma$- partial widths relevant for astrophysics.

  14. New method for summing effect corrections applied to environmental samples using gamma spectrometry

    International Nuclear Information System (INIS)

    The analysis by gamma spectrometry of low-level activity environmental samples requires the sample to be placed closest to the detector. In case of a radionuclide with a complex decay scheme, the summing effects due to photons emitted in cascade can bias drastically the activity calculation (from a few percent up to a few tens percent). The presented method enables the user to take into account the whole decay scheme, whatever the radionuclide under study, its number of energy level and decay mode. Despite the nuclear data related to the scheme, this method requires the knowledge of the full-energy peak efficiency curve as well as the total efficiency curve. Its originality relies on a recursive approach of the calculation. A complex decay scheme such as the one of Bi-214 is treated in less than one hour. The method was validated in the context of an international proficiency test, with correction factors up to 40%. A derived use of the method allows the analysis of a peak issued from the summation of photons for the activity determination of the considered radionuclide, especially in case of a well-type Germanium detector. This possibility can also lead to the validation of a detected radionuclide and even reduce the minimum detectable activity in case of multiple interferences. (author)

  15. Investigation of local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds using perturbed angular correlation gamma-gamma spectroscopy

    International Nuclear Information System (INIS)

    This work presents, from a microscopic point of view, a systematic study of the local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds through measurements of hyperfine interactions using the Perturbed Angular Correlation Gamma- Gamma Spectroscopy technique with 111In → 111Cd and 140La → 140Ce as probe nuclei. As the magnetism in these compounds originates from the 4f electrons of the rare-earth elements it is interesting to observe in a systematic study of RZn compounds the behavior of the magnetic hyperfine field with the variation of the number of 4f electrons in the R element. The use of probe nuclei 140La → 140Ce is interesting because Ce+3 ion posses one 4f electron which may contribute to the total hyperfine field, and the results showed anomalous behavior. The results for 111Cd probe showed that the temperature dependence of the magnetic hyperfine field follows the Brillouin function, and the magnetic hyperfine field decreases linearly with increase of the atomic number of rare earth when plotted as a function of the rare-earth J spin projection, showing that the main contribution to the magnetic hyperfine field in RZn compounds comes from the polarization of the conduction electrons. The results for the electric field gradient measured with 111Cd for all compounds showed a strong decrease with the atomic number of the rare-earth element. We have therefore assumed that the major contribution to the electric field gradient originates from the 4f electrons of the rare-earths. The measurements of the electric field gradient for GdCu with 111Cd, after temperature decreases and increases again showed that two different structures, CsCl-type cubic and FeB-type orthorhombic structures co-exist. Finally, it is the first time that measurements of hyperfine parameters have been carried out with theses two probe nuclei in the studied RZn. (author)

  16. Nuclear spectroscopy applied to the in-line 'ISOLDE' isotope separator

    CERN Document Server

    Knipper, A

    1981-01-01

    Reference is made to the CERN synchrocyclotron used on the 'ISOLDE' project for nuclear spectroscopy where radioactive isotopes are collected between 10 KeV and 10 MeV. Energy diagrams are presented and reference is made to a /sup 185//sub 77/Ir/sub 108/ system. Tests on argon samples are compared with those on potassium and on calcium. It is concluded that nuclear spectroscopy should have wide applications. (35 refs).

  17. Quantification of {sup 235} U and {sup 226} Ra in soil samples by means of Gamma spectroscopy; Cuantificacion de {sup 235} U y {sup 226} Ra en muestras de suelo por medio de espectrometria gamma

    Energy Technology Data Exchange (ETDEWEB)

    Quintero P, E.; Rojas M, V.P.; Montes M, F.R.; Gaso P, M.I.; Cervantes N, M.L. [Gerencia de Innovacion Tecnologica, A.P. 18-1027, C.P. 11801 Mexico D.F. (Mexico)

    2000-07-01

    In this work it is presented the Gamma Spectroscopy method which is realized in the Environmental Radiological Surveillance Laboratory using the option of deconvolution of a commercial software for the quantification of {sup 235} U and {sup 226} Ra; also is presented the method for the {sup 226} Ra correction activity. (Author)

  18. Determination of natural radioactive elements in Abo Zaabal, Egypt by means of gamma spectroscopy

    International Nuclear Information System (INIS)

    Highlights: ► We examined the radioactivity of different type samples from Abo Zaabaal Lake. ► We evaluated the natural nuclide gamma-ray activities and their annual dose rates. ► We evaluated the concentrations of 226Ra and its hazard indices. ► We assessed the absorbed dose in human. ► All results are within normal ranges. - Abstract: The natural nuclide gamma-ray activities and their respective annual effective dose rates, produced by 238U, 232Th, 40K and 226Ra, are determined for 10 different natural samples (soil–plant–water) from Abo Zaabaal Lake. This lake is located very close to the Egyptian reactors. The gamma spectra analysis indicates that the photo-gamma lines represent ten radioactive nuclides 234Th, 239Pu, 228Ac, 226Ra, 212Pb, 214Pb, 208Tl, 212Bi, 214Bi and 40K. These nuclides represent the daughters of the natural radioactive series 238U and 232Th with 40K. The mean activity concentration of 238U was found to be 6.57, 10.16 and 5.44 Bq kg−1 for (soil–plant–water); 8.46, 8.33 and 6.04 Bq kg−1 of 232Th, and 136.3, 216.8 and 119.2 Bq kg−1 of 40K respectively. The mean activity concentrations of 226Ra were obtained which help to evaluate the radiation hazard indices as radium equivalent, internal and external hazard indices. In addition, to assess the radiation risk to a biosystem, the annual effective dose rate, the absorbed dose in human and the absorbed dose outdoor are also evaluated.

  19. A cylindrical xenon ionization chamber detector for high resolution, room temperature gamma radiation spectroscopy

    International Nuclear Information System (INIS)

    A 0.75 l gridded cylindrical ionization chamber gamma radiation detector using highly purified xenon near the critical point as the detection medium is described. The detector operates at room temperature with a noise subtracted intrinsic energy resolution of 1.8% at 662 keV. The detector design and performance variables are discussed in comparison to previous planar and cylindrical xenon detectors. (orig.)

  20. STUDY CONCERNING THE POSSIBILITY OF GAMMA-SPECTROSCOPY METHOD TO DETERMINE THE TOTAL POTASSIUM IN SOILS

    Directory of Open Access Journals (Sweden)

    Tamara Leah

    2011-12-01

    Full Text Available It was proved the possibility of determination the total potassium in soils by gamma-spectroscopic method with subsequent calculation of total potassium content in according to value of 40K isotope (expressed in Becquerel, Bq, using the formula: К2О, % = С . А, where: C – conversion coefficient, A – activity of isotope 40K in soil, Bq/kg. Conversion coefficient for chernozems of Moldova – C=0,00337.

  1. In-situ gamma spectroscopy; An alternative method to evaluate external effective radiation dose

    International Nuclear Information System (INIS)

    Two types of approaches are possible to estimate radiation doses from environmental radiations:(1)Measure radiation fields in the place of interest and presume that people are exposed to the same field. (2) Actual measurement on the individual members of the population studied by the use of thermoluminescent dosimeters. (TLD). The latter approach though difficult is ideal. The objective of the present study was to investigate the possibility of using the first approach using in-situ gamma spectrometry as an alternative method to evaluate the external effective dose. The results obtained in this way provide a means of evaluating both approaches. Six houses were selected for this study from an area where an average radiation dose of 5.0 micro Sv per hour was measured using a hand held survey meter. In all study sites both TLD and in-situ measurements with portable HPGE detector were carried out. The detector was calibrated for field measurements and activity concentrations of the radionuclides identified in the gamma spectra were calculated. The calculated detector efficiency values for field measurements for 1461, 1764, and 2615 keV were 2.40, 2.03 and 1.44 respectively. External effective dose was calculated using the corresponding kerma rates for the analysed radionuclides. Evaluation of the effective dose by the two approaches are reasonably correlated (r sup 2=0.87) for dose measurements between 2.0 - 6.0 mSv. In-situ measurements gave higher values than the TL readings because in-situ data are more representative of the surrounding. This study suggests that in-situ gamma spectrometry permits rapid and efficient identification and quantification of gamma emitting radionuclides on surface and subsurface soil and can be used as an alternative rapid method to determine population doses from environmental radiations particularly in an event such as a radiation contamination. TL measurements provide only an integrated dose and would require an extended time period

  2. Applying a low energy HPGe detector gamma ray spectrometric technique for the evaluation of Pu/Am ratio in biological samples

    International Nuclear Information System (INIS)

    The estimation of Pu/241Am ratio in the biological samples is an important input for the assessment of internal dose received by the workers. The radiochemical separation of Pu isotopes and 241Am in a sample followed by alpha spectrometry is a widely used technique for the determination of Pu/241Am ratio. However, this method is time consuming and many times quick estimation is required. In this work, Pu/241Am ratio in the biological sample was estimated with HPGe detector based measurements using gamma/X-rays emitted by these radionuclides. These results were compared with those obtained from alpha spectroscopy of sample after radiochemical analysis and found to be in good agreement. - Highlights: • High resolution gamma ray spectroscopy technique with low energy HPGe detector is used for the measurement of Pu isotopes and 241Am in biological samples. • Results obtained with gamma ray spectroscopy compared well with the results obtained from radiochemical analysis of sample followed by α-spectroscopy. • Results of this study will be useful for assessment and medical management of Pu/241Am embedded in tissue of workers

  3. Spectroscopy of {sup 189,187}Pb from gamma-FMA coincidences

    Energy Technology Data Exchange (ETDEWEB)

    Janssens, R.V.F.; Davids, C.N.; Blumenthal, D. [and others

    1995-08-01

    The very neutron-deficient Pb isotopes are of much current interest because they exhibit shape coexistence between a spherical groundstate and a deformed prolate excited configuration located very low in excitation energy. Last year the nucleus {sup 186}Pb was studied at the FMA in an FMA-{gamma}-{gamma} coincidence experiment. The purpose of the present measurement was to delineate, for the first time, the groundstate and near groundstate excitations in the odd Pb isotopes {sup 189,187}Pb in order to identify the orbitals which have an important role in driving the nuclear shape. The experiment was performed only very recently at the FMA with 10 Compton-suppressed Ge detectors from the Argonne Notre Dame BGO Gamma-Ray facility. {sup 187}Pb was studied with the {sup 155}Gd({sup 36}Ar,4n) reaction at 179 MeV, while {sup 189}Pb was reached with the {sup 158}Gd({sup 36}Ar,5n) reaction at the same beam energy. The analysis just began. It can already be stated that transitions in both Pb isotopes were identified and that it should be possible to establish level schemes. The presence of possible isomeric states in {sup 189}Pb will be checked in a follow-up experiment planned in Canberra. A similar measurement on {sup 187}Pb appears very difficult because of the very small cross section involved.

  4. Continuous versus pulse neutron induced gamma spectroscopy for soil carbon analysis

    International Nuclear Information System (INIS)

    Neutron induced gamma spectra analysis (NGA) provides a means of measuring carbon in large soil volumes without destructive sampling. Calibration of the NGA system must account for system background and the interference of other nuclei on the carbon peak at 4.43 MeV. Accounting for these factors produced measurements in agreement with theoretical considerations. The continuous NGA mode was twice as fast and just as accurate as the pulse mode, thus this mode was preferable for routine soil carbon analysis. - Highlights: • Calibration of the neutron induced gamma analysis system must account for system background and the interference of other nuclei (mainly silicon-28) on the carbon peak at 4.43 MeV. • Spectra measured at a height of 250 cm above the ground could be considered the NGA system background spectrum. • The experimental cascade transition coefficient for silicon-28 (i.e. ratio of 4.50–1.78 MeV gamma ray intensities) agrees well with theoretical calculations. • The NGA continuous working mode halved the measurement time compared to the pulse working mode while retaining the same degree of accuracy

  5. Gamma-ray spectroscopy of Positron Annihilation in the Milky Way

    CERN Document Server

    Siegert, Thomas; Khachatryan, Gerasim; Krause, Martin G H; Guglielmetti, Fabrizia; Greiner, Jochen; Strong, Andrew W; Zhang, Xiaoling

    2015-01-01

    The annihilation of positrons in the Galaxy's interstellar medium produces characteristic gamma-rays with a line at 511 keV. This emission has been observed with the spectrometer SPI on INTEGRAL, confirming a puzzling morphology with bright emission from an extended bulge-like region, and faint disk emission. Most plausible sources of positrons are believed to be distributed throughout the disk of the Galaxy. We aim to constrain characteristic spectral shapes for different spatial components in the disk and bulge with the high-resolution gamma-ray spectrometer SPI, based on a new instrumental background method and detailed multi-component sky model fitting. We confirm the detection of the main extended components of characteristic annihilation gamma-ray signatures at 58$\\sigma$ significance in the line. The total Galactic line intensity amounts to $(2.7\\pm0.3)\\times10^{-3}~\\mathrm{ph~cm^{-2}~s^{-1}}$ for our assumed spatial model. We derive spectra for the bulge and disk, and a central point-like and at the p...

  6. Optimization of virtual Frisch-grid CdZnTe detector designs for imaging and spectroscopy of gamma rays

    Science.gov (United States)

    Bolotnikov, A. E.; Abdul-Jabbar, N. M.; Babalola, S.; Camarda, G. S.; Cui, Y.; Hossain, A.; Jackson, E.; Jackson, H.; James, J. R.; Luryi, A. L.; James, R. B.

    2007-09-01

    In the past, various virtual Frisch-grid designs have been proposed for cadmium zinc telluride (CZT) and other compound semiconductor detectors. These include three-terminal, semi-spherical, CAPture, Frisch-ring, capacitive Frisch-grid and pixel devices (along with their modifications). Among them, the Frisch-grid design employing a non-contacting ring extended over the entire side surfaces of parallelepiped-shaped CZT crystals is the most promising. The defect-free parallelepiped-shaped crystals with typical dimensions of 5x5x12 mm3 are easy to produce and can be arranged into large arrays used for imaging and gamma-ray spectroscopy. In this paper, we report on further advances of the virtual Frisch-grid detector design for the parallelepiped-shaped CZT crystals. Both the experimental testing and modelling results are described.

  7. High-resolution gamma-ray spectroscopy with a microwave-multiplexed transition-edge sensor array

    CERN Document Server

    Noroozian, Omid; Bennett, Douglas A; Brevik, Justus A; Fowler, Joseph W; Gao, Jiansong; Hilton, Gene C; Horansky, Robert D; Irwin, Kent D; Kang, Zhao; Schmidt, Daniel R; Vale, Leila R; Ullom, Joel N

    2013-01-01

    We demonstrate very high resolution photon spectroscopy with a microwave-multiplexed two-pixel transition-edge sensor (TES) array. We measured a $^{153}$Gd photon source and achieved an energy resolution of 63 eV full-width-at-half-maximum at 97 keV and an equivalent readout system noise of 86 pA/$\\sqrt{\\text{Hz}}$ at the TES. The readout circuit consists of superconducting microwave resonators coupled to radio-frequency superconducting-quantum-interference-devices (SQUID) and transduces changes in input current to changes in phase of a microwave signal. We use flux-ramp modulation to linearize the response and evade low-frequency noise. This demonstration establishes one path for the readout of cryogenic X-ray and gamma-ray sensor arrays with more than $10^3$ elements and spectral resolving powers $R=\\lambda/\\Delta\\lambda > 10^3$.

  8. OSIRIS-Gamma-ray spectroscopy software for on-site inspections under the Comprehensive Nuclear-Test-Ban Treaty

    Science.gov (United States)

    Caffrey, A. J.; Bowyer, T. W.; Egger, A. E.; Hall, J. C.; Kelly, S. M.; Krebs, K. M.; Kreek, S. A.; Jordan, D. V.; Milbrath, B. D.; Padgett, S. W.; Wharton, C. J.; Wimer, N. G.

    2015-06-01

    We have designed and tested software for the acquisition and analysis of high-resolution gamma-ray spectra during on-site inspections under the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The On-Site Inspection RadioIsotopic Spectroscopy-OSIRIS-software filters the spectral data to display only radioisotopic information relevant to CTBT on-site inspections, e.g.,131I. A set of over 100 fission-product spectra was employed for OSIRIS testing. These spectra were measured where possible, or generated by modeling. The test spectral compositions include non-nuclear-explosion scenarios, e.g., a severe nuclear reactor accident, and nuclear-explosion scenarios such as a vented underground nuclear test. Comparing its computer-based analyses to expert visual analyses of the test spectra, OSIRIS correctly identifies CTBT-relevant fission product isotopes at the 95% level or better.

  9. OPTIMIZATION OF VIRTUAL FRISCH-GRID CdZnTe DETECTOR DESIGNS FOR IMAGING AND SPECTROSCOPY OF GAMMA RAYS

    International Nuclear Information System (INIS)

    In the past, various virtual Frisch-grid designs have been proposed for cadmium zinc telluride (CZT) and other compound semiconductor detectors. These include three-terminal, semi-spherical, CAPture, Frisch-ring, capacitive Frisch-grid and pixel devices (along with their modifications). Among them, the Frisch-grid design employing a non-contacting ring extended over the entire side surfaces of parallelepiped-shaped CZT crystals is the most promising. The defect-free parallelepiped-shaped crystals with typical dimensions of 5x5∼12 mm3 are easy to produce and can be arranged into large arrays used for imaging and gamma-ray spectroscopy. In this paper, we report on further advances of the virtual Frisch-grid detector design for the parallelepiped-shaped CZT crystals. Both the experimental testing and modeling results are described

  10. Comparative study of radioprotective properties of serotin derivatives repeatedly applied before gamma irradiation

    International Nuclear Information System (INIS)

    In the experiments on albino mice, the phenomenon of desensitization has been studied by a specific activity and some pharmacologic properties of serotonin, mexamin and 5-acetyloxytryptamine, the time-intervals between injections of the preparations being 5, 30 and 60 minutes, 2, 3, 4, 6, 8 and 24 hours. A correlation has been found between changes in radioprotective and pharmacologic properties (as determined by the accumulation of the dye in the splenic tissue) after repeated administration of mexamin. The phenomenon of desensitization is probably dependent not only on the chemical nature and mechanism of action of the protectors but also on the conditions under which they are repeatedly applied

  11. Laser spectroscopy: Assessment of research needs for laser technologies applied to advanced spectroscopic methods

    International Nuclear Information System (INIS)

    This report is organized as follows. Section 2 summarizes the current program of DOE's Office of Health and Environmental Research (OHER) and provides some remarks on low laser science and technology could beneficially impact most of the research programs. Section 3 provides a brief global perspective on laser technology and attempts to define important trends in the field. Similarly, Section 4 provides a global perspective on laser spectroscopy and addresses important trends. Thus, Section 5 focuses on the trends in laser technology and spectroscopy which could impact the OHER mission in significant ways and contains the basis for recommendations made in the executive summary. For those with limited familiarity with laser technology and laser spectroscopy, reference is made to Appendix 1 for a list of abbreviations and acronyms. Appendix 2 can serve a useful review or tutorial for those who are not deeply involved with laser spectroscopy. Even those familiar with laser spectroscopy and laser technology may find it useful to know precisely what the authors of this document mean by certain specialized terms and expressions. Finally, a note on the style of referencing may be appropriate. Whenever possible a book or review articles is referenced as the preferred citation. However, we frequently found it useful to reference a number of individual papers of recent origin or those which were not conveniently found in the review articles

  12. A NIM (Nuclear Instrumentation Module) system conjugated with optional input for pHEMT amplifier for beta and gamma spectroscopy

    International Nuclear Information System (INIS)

    This work presents a high speed NIM module (Nuclear Instrumentation Module) to detect radiation, gamma and muons, as part of a system for natural radiation monitoring and of extraterrestrial origin. The subsystem developed consists of a preamplifier and an integrated SCA (Single Channel Analyzer), including power supplies of ± 12 and ± 24V with derivations of +3.6 and ± 5V. The single channel analyzer board, consisting of discrete logic components, operating in window modes, normal and integral. The pulse shaping block is made up of two voltage comparators working at 120 MHz with a response time > 60 ns and a logic anticoincidence system. The preamplifier promotes a noise reduction and introduces the impedance matching between the output of anode / diode photomultiplier tubes (PMTs) and subsequent equipment, providing an input impedance of 1MΩ and output impedance of 40 to 140Ω. The shaper amplifier is non-inverting and has variable input capacitance of 1000 pF. The upper and lower thresholds of the SCA are adjustable from 0 to ± 10V, and the equipment is compatible with various types of detectors, like PMTs coupled to sodium iodide crystals. For use with liquid scintillators and photodiodes with crystals (CsI: Tl) is proposed to include a preamplifier circuit pHEMT (pseudomorphic High Electron Mobility Transistor) integrated. Yet, the system presents the possibility of applications for various purposes of gamma spectroscopy and automatic detection of events producing of beta particles

  13. Low-energy gamma-ray spectroscopy using an X-ray-escape gated proportional counter

    DEFF Research Database (Denmark)

    Gregers Hansen, P.; Nielsen, H.L.; Williams, E.T.; Wilsky, K.

    1965-01-01

    The utility of a gas-filled proportional counter in low-energy γ spectroscopy is greatly increased if it is operated in coincidence with an escaping fluorescent X-ray. An apparatus, having an efficiency greater than 10% of singles, is described and several examples are given. An efficiency curve is...

  14. Spectroscopy

    CERN Document Server

    Walker, S

    1976-01-01

    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  15. High-sensitivity gamma spectroscopy for extended sources. Application to activity measurements on the human body, on glass, and on soil

    International Nuclear Information System (INIS)

    The measurement and location by gamma spectroscopy of human body internal contaminations at maximum permissible levels, and, in certain cases, at lower activities such as that due to 40K was investigated. The characteristics of the high-sensitivity apparatus used are given, and several assemblies using large-volume NaI(Tl) scintillators are described. The relatively light shielding required for natural radioactivity permitted construction of mobile assembly. Conditions of use are described, and the results are given. All gamma emitting elements were measured in 15 min at levels lower than the tolerance dose. Gamma spectroscopy was also used to determine fission products in the earth and to study radioactive elements in the presence of other emitters. (author)

  16. Gamma-ray spectroscopy applications in radiation control and environmental monitoring

    International Nuclear Information System (INIS)

    A method for stabilization of gamma-ray spectrometers energy calibration is proposed. It is based on recalibration of the spectrum by numerical filtration. The possibility of efficiency auto-calibration is considered in the case when a reference source with appropriate shape is unavailable. The method is tested by estimation of the effective thickness of a lead plate (self-absorption). Potential applications include the evaluation of surface pollution infiltration depth as well as the development of pure beta sources (e.g. Sr-90) using the registration of their Bremsstrahlung. 6 refs

  17. Combined in-beam electron and gamma-ray spectroscopy of (184,186)Hg

    CERN Document Server

    Scheck, M; Rahkila, P; Butler, P A; Larsen, A C; Sandzelius, M; Scholey, C; Carrol, R J; Papadakis, P; Jakobsson, U; Grahn, T; Joss, D T; Watkins, H V; Juutinen, S; Bree, N; Cox, D; Huyse, M; Uusitalo, J; Leino, M; Ruotsalainen, P; Nieminen, P; Srebrny, J; Van Duppen, P; Herzan, A; Greenlees, P T; Julin, R; Herzberg, R D; Hauschild, K; Pakarinen, J; Page, R D; Peura, P; Gaffney, L P; Kowalczyk, M; Rinta-Antila, S; Saren, J; Lopez-Martens, A; Sorri, J; Ketelhut, S

    2011-01-01

    By exploiting the SAGE spectrometer a simultaneous measurement of conversion electrons and gamma rays emitted in the de-excitation of excited levels in the neutron-deficient nuclei (184,186)Hg was performed. The light Hg isotopes under investigation were produced using the 4n channels of the fusion-evaporation reactions of (40)Ar and (148,150)Sm. The measured K- and L-conversion electron ratios confirmed the stretched E2 nature of several transitions of the yrast bands in (184,186)Hg. Additional information on the E0 component of the 2(2)(+) -> 2(1)(+) transition in (186)Hg was obtained.

  18. The nuclear data ND-6700 system for gamma spectroscopy at Winfrith

    International Nuclear Information System (INIS)

    The ND-6700 is a computerised counting system for measuring and recording emissions from a wide range of radioactive sources. This system as used at Winfrith consists of a central dedicated minicomputer, two terminals, two printers, and four detectors with associated counting electronics. Samples may be counted and the resulting gamma-ray spectra stored in a data file for subsequent analysis using the system's software. This report describes the ND-6700 system in detail, and provides a series of instructions for its operation and documentation for user written software. (UK)

  19. Evaluation of cross-sections for particle induced gamma-ray emission (PIGE) spectroscopy

    International Nuclear Information System (INIS)

    The extension of the cross-section evaluation procedure to PIGE data was investigated and the first results are reported. Two different cases were studied: the gamma emission accompanying inelastic scattering of protons, and the (p,γ)-reaction. The corresponding theoretical calculations were performed in the framework of R-matrix and DWBA for the (p,p′γ) reaction on 23Na, and using statistical model for the proton radiative capture by 52Cr. The possibility of achieving a close fit to the experimental data is demonstrated

  20. Time-resolved diffusing wave spectroscopy applied to dynamic heterogeneity imaging

    CERN Document Server

    Cheikh, M; Ettori, D; Tinet, E; Avrillier, S; Tualle, J M; Cheikh, Monia; Nghiem, Ha Lien; Ettori, Dominique; Tinet, Eric; Avrillier, Sigrid; Tualle, Jean-Michel

    2006-01-01

    We report in this paper what is to our knowledge the first observation of a time-resolved diffusing wave spectroscopy signal recorded by transillumination through a thick turbid medium: the DWS signal is measured for a fixed photon transit time, which opens the possibility of improving the spatial resolution. This technique could find biomedical applications, especially in mammography.

  1. 238U And 232Th Concentration In Rock Samples using Alpha Autoradiography and Gamma Spectroscopy Techniques

    International Nuclear Information System (INIS)

    The activity concentrations of uranium and thorium were measured for some rock samples selected from Dahab region in the south tip of Sinai. In order to detect any harmful radiation that would affect on the tourists and is becoming economic resource because Dahab have open fields of tourism in Egypt. The activity concentration of uranium and thorium in rocks samples was measured using two techniques. The first is .-autoradiography technique with LR-115 and CR-39 detectors and the second is gamma spectroscopic technique with NaI(Tl) detector. It was found that the average activity concentrations of uranium and thorium using .-autoradiography technique ranged from 6.41-49.31 Bqkg-1, 4.86- 40.87 Bqkg-1 respectively and by gamma detector are ranged from 6.70- 49.50 Bqkg-1, 4.47- 42.33 Bqkg-1 respectively. From the obtained data we can conclude that there is no radioactive healthy hazard for human and living beings in the area under investigation. It was found that there are no big differences between the calculated thorium to uranium ratios in both techniques

  2. Studies of natural radioactivity in cement products using gamma ray spectroscopy

    International Nuclear Information System (INIS)

    Evidence from our earlier study on several types of building materials has shown that cement contains a substantial amount of natural occurring radioactive materials. There are many brands of cement products available in Malaysia. Although the basic ingredients of cement are similar across brand, their proportion varies. In this study we have selected twelve brands of cement products which are analysed for natural radioactivity (U,Th,K) using gamma ray spectrometry. The gamma energies of interest are 583.1 keV, 609.3 keV and 1460 keV for nuclides 208Tl, 214Bi and 40K respectively. Our findings show a relatively high activity of 40K for all cement brands, ranging from 33 Bq/kg to as high as 3010 Bq/kg. Uranium activity ranges from 9Bq/kg to 672 Bq/kg while thorium activity was found range from 6Bq/kg to 94 Bq/kg. The radium equivalent activity is calculated for all brands and the values obtained range between 24 Bq/kg to 879 Bq/kg. Eight out of twelve products possess radium equivalent greater than 370 Bq/kg, a threshold limit for radiation dose equivalent to 1.5 mSv per annum. (author)

  3. Effects of applied stress and plastic strain on. gamma. r reversible. epsilon. martensitic transformation in high Mn alloy polyctystals. Ko Mn tetsu gokin takessho ni okeru. gamma. r reversible. epsilon. martensite hentai ni oyobosu gairyoku to hizumi no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Tomota, Y.; Piao, M.; Hasunuma, T.; Kimura, Y. (Ibaraki Univ., Ibaraki (Japan))

    1990-06-20

    The influences of applied stress and plastic strain on a transformation austenite ({gamma}) to hcp martensite ({epsilon}) were studied on Fe-16wt%Mn, Fe-24wt%Mn, and Fe-24%Mn-6%Si alloy, and a transformation mechanism and a shape memory phenomenon were more deeply examined. As the quenching structure of three kinds of the alloys consists of two phases of {gamma} and {epsilon}, the specimens were cooled after heated above the A {sub f} temperature to keep {gamma} single phase, and then the tensile tests were carried out. Positive temperature dependence was found under the 0.2% proof stress due to stress-induced {gamma}{yields} {epsilon} transformation in each of Fe-Mn alloy and Fe-24%Mn-6%Si alloy. When {gamma} phase of Fe-24%Mn alloy stabilized due to cyclic transformation was stretched at room temperature, the yield stress was remarkably lowered by the stress-induced {gamma}{r arrow}{epsilon} transformation. When the specimens were stretched at 523K under stress which was larger than the yield strength and then cooled, the elongation along the applied stress direction due to martensitic tranformation was recognized. A shape recovery was remarkable in Si content alloys. 22 refs., 5 figs.

  4. Limits of studying high-spin states by discrete-line gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    Recent (HI, xn) data on rotational Yb and Hf nuclei are used to describe the motivations and techniques for pushing discrete-line spectroscopy to the realm of the weakly populated yrast and non-yrast states. Three aspects of these studies are discussed: extraction of moments of inertia in different aligned bands, observation and understanding of high-frequency band crossings, and dependence of feeding patterns on nuclear structure

  5. Time resolving imaging spectroscopy applied to the analysis of plasmas generated by pulsed lasers

    Energy Technology Data Exchange (ETDEWEB)

    Alvira, F C; Bilmes, G M [Centro de Investigaciones Opticas (CONICET La Plata-CIC) CC 3, 1897, Gonnet, La Plata, Buenos Aires (Argentina); Ponce, L; Arronte, M, E-mail: fcalvira@ciop.unlp.edu.ar [CICATA-IPN, Unidad Altamira, Altamira 89600, Tamps (Mexico)

    2011-01-01

    Time resolved imaging spectroscopy were used to study the spatial and temporal evolution of LIBS (Laser Induced Breakdown Spectroscopy) plasmas generated in Cu substrates by laser pulses of different duration. Long laser pulses (microsecond) and short laser pulses (nanosecond) as well as multipulse emission were used for excitation. Analysis was made by using an imaging spectrometer with time resolved detection. Results show that the use of long laser excitation pulses produce emission spectra with the same signal to noise ratio, but with lower resolution than those produced with shorter ones. The different species generated in LIBS experiments as neutral or single ionized have a different spatial distribution inside the plasma. We demonstrated that using spatial discrimination procedures is possible to obtain spectra with the same signal to noise ratio than those obtained with a gating detector. In this case an appreciable advantage in cost reduction is obtained by replacing the gating detector by a cheap screen.

  6. Time resolving imaging spectroscopy applied to the analysis of plasmas generated by pulsed lasers

    International Nuclear Information System (INIS)

    Time resolved imaging spectroscopy were used to study the spatial and temporal evolution of LIBS (Laser Induced Breakdown Spectroscopy) plasmas generated in Cu substrates by laser pulses of different duration. Long laser pulses (microsecond) and short laser pulses (nanosecond) as well as multipulse emission were used for excitation. Analysis was made by using an imaging spectrometer with time resolved detection. Results show that the use of long laser excitation pulses produce emission spectra with the same signal to noise ratio, but with lower resolution than those produced with shorter ones. The different species generated in LIBS experiments as neutral or single ionized have a different spatial distribution inside the plasma. We demonstrated that using spatial discrimination procedures is possible to obtain spectra with the same signal to noise ratio than those obtained with a gating detector. In this case an appreciable advantage in cost reduction is obtained by replacing the gating detector by a cheap screen.

  7. 7Be analyses in seawater by low background gamma-spectroscopy

    International Nuclear Information System (INIS)

    Oceanographers use the cosmogenic radionuclide 7Be (T1/2 53 days) as a tracer for atmospheric input and a conservative tracer of mixing in the open ocean. This paper elucidates a method for improving the analysis of 7Be from seawater. The scavenging efficiency of Fe(OH)3 for each sample is measured by ICP-MS using stable 9Be as a yield monitor. Samples are gamma-counted in a large diameter (28 mm) well detector. The high purity germanium well detector is coupled with an active anti-coincidence cosmic guard to reduce the spectra background. The improved overall accuracy of the method and lower detection limit of the detector results in a lower volume of seawater needed for analyses. Results will be shown from a study of 7Be in the Sargasso Sea. (author)

  8. Development of a Reference Database for Particle-Induced Gamma-ray Emission spectroscopy

    Science.gov (United States)

    Dimitriou, P.; Becker, H.-W.; Bogdanović-Radović, I.; Chiari, M.; Goncharov, A.; Jesus, A. P.; Kakuee, O.; Kiss, A. Z.; Lagoyannis, A.; Räisänen, J.; Strivay, D.; Zucchiatti, A.

    2016-03-01

    Particle-Induced Gamma-ray Emission (PIGE) is a powerful analytical technique that exploits the interactions of rapid charged particles with nuclei located near a sample surface to determine the composition and structure of the surface regions of solids by measurement of characteristic prompt γ rays. The potential for depth profiling of this technique has long been recognized, however, the implementation has been limited owing to insufficient knowledge of the physical data and lack of suitable user-friendly computer codes for the applications. Although a considerable body of published data exists in the nuclear physics literature for nuclear reaction cross sections with γ rays in the exit channel, there is no up-to-date, comprehensive compilation specifically dedicated to IBA applications. A number of PIGE cross-section data had already been uploaded to the Ion Beam Analysis Nuclear Data Library (IBANDL)

  9. DuMond curved crystal spectrometer for in-beam X- and gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    An in-beam curved crystal spectrometer facility has been installed at the SIN variable energy cyclotron. The radius of curvature is 3.15 m. Using the (110) planes of different bent quartz laminas, diffraction peaks down to Δθ = 5 arcsec FWHM are obtained. The energy resolution is thus ΔE ≅ 0.01 E2/n, where n is the diffraction order, ΔE being expressed in eV and E in keV. The spectrometer has been constructed to cover an angular range of ±100. Transitions in the range 17 to about 350 keV have so far been observed. Measurements have been performed in conventional line source DuMond geometry and in slit geometry. The instrument is being used for the high-resolution observation of X- and gamma-rays induced by proton, helium- and oxygen-ion bombardment. (orig.)

  10. Calibration of a telescope for gamma spectroscopy using a new configuration of Ge (Li) diodes

    International Nuclear Information System (INIS)

    It was developed a telescope to measure gamma-rays in the energy interval 10-1500 KeV, using two Ge (Li) diodes of 40 cm3 each, coaxially mounted in the same cryostat and an anticoincidence NaI (Tl) shielding system. This new configuration allows a much better signal to noise ratio due to the lower diode operating in anticoincidence with the upper one; besides that, one has a high energy resolution ΔE241, Na22 and Eu152 are described. From the analysis of the data obtained in the sum coincidente mode, a minimum detectable flux at 511 KeV is estimated to be >or approx. 2x10-3 fotons cm-2 s-1, with a statistical significance of 3σ for 10 hours of observing time at 3mb of residual atmosfere. That is about the minimun line flux emmitted by the Galactic Center. (Author)

  11. gamma-ray DBSCAN: a clustering algorithm applied to Fermi-LAT gamma-ray data. I. Detection performances with real and simulated data

    OpenAIRE

    Tramacere, A.; Vecchio, C.

    2012-01-01

    The Density Based Spatial Clustering of Applications with Noise (DBSCAN) is a topometric algorithm used to cluster spatial data that are affected by background noise. For the first time, we propose the use of this method for the detection of sources in gamma-ray astrophysical images obtained from the Fermi-LAT data, where each point corresponds to the arrival direction of a photon. We investigate the detection performance of the gamma-ray DBSCAN in terms of detection efficiency and rejection ...

  12. Electron spin resonance (ESR) spectroscopy applied to radiation dosimetry and other fields

    International Nuclear Information System (INIS)

    A short introduction to the theory and practice of ESR spectroscopy is given. ESR alanine dosimetry for low and high LET (linear energy transfer) ionising radiation is described, indicating its advantages over traditional methods. Problems arising in the therapy dose range (below 5 Gy), and possible future developments, are mentioned. The application of ESR to the radiation processing of materials and foodstuffs, to geological dating, biology, molecular chemistry and to medicine is discussed. Some examples of chemical analyses are also presented. (orig.)

  13. In Situ Soft X-ray Spectroscopies Applied to Atmospheric Corrosion And Related Systems

    OpenAIRE

    Forsberg, Johan

    2009-01-01

    This thesis concerns the application of various soft x-ray spectroscopic methods (soft x-ray absorption, SXA, and emission, SXE) to complex, non-vacuum compatible systems, including liquids and multi-phase systems. The design, construction, and application of new instrumentation for in situ spectroscopy is described in detail. This includes sample holders using thin soft x-ray transparent membranes to enable measurements on systems completely isolated from vacuum, enabling flow of e.g. liquid...

  14. Studying phase structure of burned ferrous manganese ores by method of nuclear gamma-resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    B. Shayakhmetov

    2014-04-01

    Full Text Available In the given article there are presented the results of studying the phase structure of burned ferrous manganese ores of Zhomart and Zapadny Kamys deposits of by the method of Mossbauer spectroscopy. There is established a variety of iron location forms in the studied materials and their quantitative content that allows to define the degree of completing regenerative processes at magnetizing roasting, and also the processes of formation of solid solutions (Fe1-XMX3O4 and stabilization of Fe1-XO from eutectoid disintegration at cooling.

  15. Gamma-ray spectroscopy of 12ΛC via the (π+,K+) reaction

    International Nuclear Information System (INIS)

    A γ-ray spectroscopy experiment via the 12C(π+,K+) reaction was carried out at KEK-PS in 2005. The K6 beam line and Superconducting Kaon Spectrometer (SKS) were employed to obtain a missing mass spectrum for 12ΛC. An upgraded germanium detector array, Hyperball2, was introduced to detect γ rays emitted from hypernuclei in coincidence with the (π+,K+) reaction. As a result of further analysis, a γ-ray peak at 6048 keV (preliminary) was newly observed and assigned as the M1 transition from the 6-MeV excited state to the ground state

  16. Gamma and electron spectroscopy of transfermium isotopes at Dubna: Results and plans

    Indian Academy of Sciences (India)

    A Yeremin; O Malyshev; A Popeko; A Lopez-Martens; K Hauschild; O Dorvaux; S Saro; D Pantelica; S Mullin

    2010-07-01

    Detailed spectroscopic information of excited nuclear states in deformed transfermium nuclei is scarce. Most of the information available today has been obtained from investigations of fine-structure -decay. Although decay gives access to hindrance factors and lifetimes which are strongly correlated to shell/subshell closures and the presence of isomers, only the combined use of and conversion electron spectroscopy allows the precise determination of excitation energy, spin and parity of nuclear levels. In the years 2004–2009 using the GABRIELA set-up [Hauschild et al, Nucl. Instrum. Methods A560, 388 (2006)] at the focal plane of VASSILISSA separator [Malyshev et al, Nucl. Instrum. Methods A440, 86 (2000); A516, 529 (2004)] experiments with the aim of and electron spectroscopy of the isotopes from Fm to Lr, formed by complete fusion reactions with accelerated heavy ions were performed. In the following, the pre- liminary results of decay studies using - and - coincidences at the focal plane of the VASSILISSA recoil separator are presented. Accumulated experience allowed us to perform ion optical calculations and to design the new experimental set-up, which will collect the base and best parameters of the existing separators and complex detector systems used at the focal planes of these installations. In the near future it is planned to study neutron-rich isotopes of the Rf–Sg in the `hot’ fusion reactions with 22Ne incident projectiles and 242Pu, 243Am and 248Cm targets.

  17. The art of digital spectroscopy - a new tool in action

    International Nuclear Information System (INIS)

    A new generation of pulse processing electronics was successfully tested on-line and applied for the first time in particle and gamma-ray spectroscopy experiments. It is based on a digital signal processing (DSP) technology. (orig.)

  18. Time resolved spectroscopy of SGR J1550–5418 bursts detected with Fermi/gamma-ray burst monitor

    International Nuclear Information System (INIS)

    We report on a time-resolved spectroscopy of the 63 brightest bursts of SGR J1550–5418, detected with the Fermi/Gamma-ray Burst Monitor during its 2008-2009 intense bursting episode. We performed spectral analysis down to 4 ms timescales to characterize the spectral evolution of the bursts. Using a Comptonized model, we find that the peak energy, E peak, anti-correlates with flux, while the low-energy photon index remains constant at ∼ – 0.8 up to a flux limit F ≈ 10–5 erg s–1 cm–2. Above this flux value, the E peak–flux correlation changes sign, and the index positively correlates with the flux reaching ∼1 at the highest fluxes. Using a two blackbody model, we find that the areas and fluxes of the two emitting regions correlate positively. Further, we study here for the first time the evolution of the temperatures and areas as a function of flux. We find that the area–kT relation follows the lines of constant luminosity at the lowest fluxes, R 2∝kT –4, with a break at the higher fluxes (F > 10–5.5 erg s–1 cm–2). The area of the high-kT component increases with the flux while its temperature decreases, which we interpret as being due to an adiabatic cooling process. The area of the low-kT component, on the other hand, appears to saturate at the highest fluxes, toward R max ≈ 30 km. Assuming that crust quakes are responsible for soft gamma repeater (SGR) bursts and considering R max as the maximum radius of the emitting photon-pair plasma fireball, we relate this saturation radius to a minimum excitation radius of the magnetosphere, and we put a lower limit on the internal magnetic field of SGR J1550–5418, B int ≳ 4.5 × 1015 G.

  19. Time Resolved Spectroscopy of SGR J1550-5418 Bursts Detected with Fermi/Gamma-Ray Burst Monitor

    Science.gov (United States)

    Younes, G.; Kouveliotou, C.; van der Horst, A. J.; Baring, M. G.; Granot, J.; Watts, A. L.; Bhat, P. N.; Collazzi, A.; Gehrels, N.; Gorgone, N.; Göğüş, E.; Gruber, D.; Grunblatt, S.; Huppenkothen, D.; Kaneko, Y.; von Kienlin, A.; van der Klis, M.; Lin, L.; Mcenery, J.; van Putten, T.; Wijers, R. A. M. J.

    2014-04-01

    We report on a time-resolved spectroscopy of the 63 brightest bursts of SGR J1550-5418, detected with the Fermi/Gamma-ray Burst Monitor during its 2008-2009 intense bursting episode. We performed spectral analysis down to 4 ms timescales to characterize the spectral evolution of the bursts. Using a Comptonized model, we find that the peak energy, E peak, anti-correlates with flux, while the low-energy photon index remains constant at ~ - 0.8 up to a flux limit F ≈ 10-5 erg s-1 cm-2. Above this flux value, the E peak-flux correlation changes sign, and the index positively correlates with the flux reaching ~1 at the highest fluxes. Using a two blackbody model, we find that the areas and fluxes of the two emitting regions correlate positively. Further, we study here for the first time the evolution of the temperatures and areas as a function of flux. We find that the area-kT relation follows the lines of constant luminosity at the lowest fluxes, R 2vpropkT -4, with a break at the higher fluxes (F > 10-5.5 erg s-1 cm-2). The area of the high-kT component increases with the flux while its temperature decreases, which we interpret as being due to an adiabatic cooling process. The area of the low-kT component, on the other hand, appears to saturate at the highest fluxes, toward R max ≈ 30 km. Assuming that crust quakes are responsible for soft gamma repeater (SGR) bursts and considering R max as the maximum radius of the emitting photon-pair plasma fireball, we relate this saturation radius to a minimum excitation radius of the magnetosphere, and we put a lower limit on the internal magnetic field of SGR J1550-5418, B int >~ 4.5 × 1015 G.

  20. Determination of Spin State in Dinuclear Iron(II) Coordination Compounds Using Applied Field Moessbauer Spectroscopy

    International Nuclear Information System (INIS)

    So far there has been no direct method to determine the spin state of molecules in dinuclear iron(II) compounds. The molecular fractions of high spin (HS) and low spin (LS) species have been deduced from magnetic susceptibility and zero field Moessbauer spectroscopy data irrespective of whether they belong to LS-LS, LS-HS and HS-HS pairs. However, the distinction of pairs becomes possible if Moessbauer measurements are carried out in an external magnetic field. The proposed method opens new possibilities in the study of spin crossover phenomena in dinuclear compounds.

  1. Photoacoustic spectroscopy applied to the study of the influence of laser irradiation on corn seeds

    Science.gov (United States)

    Hernández Aguilar, C.; Carballo C., A.; Cruz-Orea, A.; Ivanov, R.; San Martín Martínez, E.; Michtchenko, A.

    2005-06-01

    In the present study we were interested in the effects of low intensity laser irradiation on hybrid corn seeds CL1 x CL4 when these seeds were exposed to different laser intensities and irradiation times. In order to observe qualitative differences in chlorophyll a and b optical absorption spectra of seedling’s leaves, whose seeds were irradiated and non irradiated, were obtained by using photoacoustic spectroscopy (PAS). A randomized complete blocks experimental design with three replications was used. The experimental unit included 10 seeds, from which we randomly choose three seedlings. The variance analysis (ANOVA) for both chlorophylls revealed significant (P treatments

  2. Near infrared spectroscopy applied to the rapid prediction of the floral origin and mineral content of honeys.

    Science.gov (United States)

    Escuredo, Olga; González-Martín, M Inmaculada; Rodríguez-Flores, M Shantal; Seijo, M Carmen

    2015-03-01

    Consumers demand to know the floral origins of honeys. Therefore, the use of simple and reliable techniques for differentiating among honeys by their origins is necessary. Multivariate statistical techniques and near infrared spectroscopy applied to palynological and mineral characteristics make it possible to differentiate among the types of honey collected from Northwestern Spain. Prediction models using a modified partial least squares regression for the main pollen types (Castanea, Eucalyptus, Rubus and Erica) in honeys and their mineral composition (potassium, calcium, magnesium and phosphorus) were established. Good multiple correlation coefficients (higher than 0.700) and acceptable standard errors of cross-validation were obtained. The ratio performance deviation exhibited a good prediction capacity for Rubus pollen and for Castanea pollen, whereas for minerals, for Eucalyptus pollen and for Erica pollen the ratio performance deviation was excellent. Near infrared spectroscopy was established as a rapid and effective tool to obtain equations of prediction that contribute to the honey typification. PMID:25306316

  3. Discrimination of Astyanax altiparanae (Characiformes, Characidae) populations by applying Fourier transform-infrared photoacoustic spectroscopy in the fish scales

    Science.gov (United States)

    de Almeida, F. S.; Santana, C. A.; Lima, D. M. V.; Andrade, L. H. C.; Súarez, Y. R.; Lima, S. M.

    2016-05-01

    Astyanax altiparanae fish species is considered very generalist and opportunist, occupying different types and sizes of environments. This characteristic turns it very appropriate as bioindicator or biomarked. Therefore, in this work, A. altiparanae fish species was used to identify populations by using the Fourier transform infrared spectroscopy directly in its scales. The discriminant analysis applied in the infrared spectra demonstrated a significant differentiation among the analyzed populations, with the first and second canonical roots explain together 100% of the data variation. The obtained results were correlated with environmental descriptors and diet of fishes, and a better agreement was obtained when spectroscopic data were compared with the composition of food present in the fish stomachs. However, this study indicates that the combination of infrared absorption spectroscopy with discriminant analysis is a very appropriate methodology to be used in fish scales as bioindicator for intraspecific study.

  4. Evaluation of the effect of gamma-ray irradiation on starch by near-infrared spectroscopy

    International Nuclear Information System (INIS)

    In order to evaluate the effect of gamma-ray irradiation on starch, near-infrared absorption spectra of four groups of starch samples, control, 10, 20 and 30 kGy irradiated, were measured. By the preliminary analysis, it was revealed that 1 702 and 2 100 nm were effective in predicting the irradiation dose on starch. On the other hand, samples were divided into calibration and validation set. The multi-regression analysis of the calibration set was carried out with adopting 1702 or 2100nm as the first wavelength, and the resulting calibration curves were named calibration A and B. Using these calibration curves, the irradiation dose of the validation set was predicted. Although the accuracy of the prediction was poor, it seemed that the non-irradiated and the irradiated samples could be discriminated by an appropriate borderline. Therefore, a new irradiation index was defined as non-irradiated = 0 and irradiated = 1. In the same way as the case of four groups, calibration C and D, in addition, calibration E, which using 1702 nm only, were developed and the irradiation index of the validation set was predicted. Although there were a few samples that could not be accurately predicted with calibration C and D, there was only one wrong discrimination with calibration E and its prediction accuracy was 96.2%

  5. Determination of radioisotopes in gamma-ray spectroscopy using abductive machine learning

    International Nuclear Information System (INIS)

    An algorithmic approach has been adopted for many years for identifying and quantifying radioisotopes in high-resolution gamma-ray spectra. Complexity of the technique, particularly when used with lower resolution detectors, warrants looking for machine-learning alternatives where intensive computations are required only during training, while actual sample analysis is greatly simplified. This should be advantageous in developing simple portable systems for fast online analysis of large numbers of samples, particularly in situations where accuracy can be traded off for speed and simplicity. Solutions based on neural networks have been reported in the literature. This paper describes the use of abductive networks which offer shorter training times and a simpler and more automated approach to model synthesis. The abductory induction mechanism (AIM) tool was used to build models for determining isotopes in both single- and multiple-isotope samples represented by spectra from an NaI(Tl) detector. Inspite of a 50-fold poorer resolution for the AIM spectral data, AIM results are adequate, with average errors ranging between 11.8% and 20.5% for a number of simulated multi-isotope cocktails. (orig.)

  6. SUPER-SABRE: an RSX-11M system for generalized gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    A system is described which provides generalized multi-user services for gamma-ray spectrometry with an existing laboratory computer. Purpose-built hardware is not employed. The current implementation is on a PDP11 computer under RSX-11M using commercial CAMAC units. The design, however, is not limited to specific hardware. Up to fourteen operators may use eight detectors or access an archive of many thousand spectra. An interactive command language is supplemented by a command file interpreter. A user may control data acquisition, manipulate, examine or analyze spectra. There is complete flexibility and independence in the use of terminals and other devices. SUPER-SABRE demonstrates particular features of computer-user interface design and provides test-bed facilities for analytical procedures within its software. It is capable of extension and modification to accommodate appropriate developments in computer technology. The current system is successfully employed in the measurement of environmental radioactivity, for radiation protection plant control and for neutron activation analysis

  7. Gamma spectroscopy for examination of light Ba isotopes after beta decay

    International Nuclear Information System (INIS)

    The low-spin states of the nuclei 126Ba, 128Ba, and 130Ba were observed in two β-decay experiments, both carried out with the OSIRIS cube, at the Cologne FN tandem accelerator. Both measurements are based on a cyclic measuring method. Lanthanum parent nuclei are created in an 'activation phase', and the gamma radiation of the barium daughter nuclei is measured after β-decay in a subsequent 'measuring phase', with the accelerator beam shut off. One significant result of both measurements is that the K=0 band could be identified for the first time in the nuclei studied. The spin could be determined in the 130Ba nucleus by an evaluation of the γγ-correlation data. As for the nuclei 126Ba and 128Ba, data in support of the spin hypothesis were found in the type of the occupying, or de-occupying, γ-transitions and in the predictions of the IBA-1 model. (orig./DG)

  8. High Resolution Chandra Spectroscopy of Gamma Cassiopeia (B0.5IVe)

    CERN Document Server

    Smith, M A; Gu, M F; Robinson, R D; Evans, N R; Schran, P G

    2004-01-01

    gamma Cas has long been famous for its unique hard X-ray characteristics. We report herein on a 53 ks Chandra HETGS observation of this target. An inspection of our spectrum shows that it is quite atypical for a massive star, with abnormally weak Fe XXV, XXVI lines, Ly-alpha lines of H-like species from Fe XVII, XXIII, XXIV, S XVI, Si XIV, Mg XII, Ne X, O VII, VIII, and N VII. Also, line ratios of the rif-triplet of for a few He-like ions XVII are consistent with the dominance of collisional atomic processes. Yet, the presence of Fe and Si fluorescence K features indicates that photoionization also occurs in nearby cold gas. The line profiles indicate a mean velocity at rest and a broadening of 500 km/s. A global fitting analysis of the line and continuum spectrum finds that there are 3-4 plasma emission components. The dominant hot (12 keV) component and has a Fe abundance of 0.22 solar. Some fraction of this component (10-30%) is heavily absorbed. The other 2-3 components, with temperatures 0.1, 0.4, 3 keV,...

  9. Lu.sub.1-xI.sub.3:Ce.sub.x-a scintillator for gamma-ray spectroscopy and time-of-flight pet

    Science.gov (United States)

    Shah, Kanai S.

    2008-02-12

    The present invention includes very fast scintillator materials including lutetium iodide doped with Cerium (Lu.sub.1-xI.sub.3:Ce.sub.x; LuI.sub.3:Ce). The LuI.sub.3 scintillator material has surprisingly good characteristics including high light output, high gamma-ray stopping efficiency, fast response, low cost, good proportionality, and minimal afterglow that the material is useful for gamma-ray spectroscopy, medical imaging, nuclear and high energy physics research, diffraction, non-destructive testing, nuclear treaty verification and safeguards, and geological exploration.

  10. Gamma-Irradiated seafoods: identification and dosimetry by electron paramagnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Electron paramagnetic resonance (EPR) spectroscopy was used to measure the production of free radicals induced by 60Co γ-rays in shrimp exoskeleton, mussel shells, and fish bones. The EPR spectrum for irradiated shrimp shell was dose dependent and appeared to be derived from more than one radical. The major component of the radiation-induced spectrum resulted from radical formation in chitin, assigned by comparison with irradiated N-acetyl-D-glucosamine. Other measurements include the total yield of radicals formed as a function of dose and the longevity of the radiation-induced EPR signal. Similar measurements were made for mussel shells and fish bones, and the results are compared and discussed. It was concluded that irradiated shrimp (with shell attached) could definitely be identified by this technique; however, precise determination of absorbed dose was less straightforward. Positive identification of irradiated fish bones was also clearly distinguishable, and dosimetry by EPR appeared to be feasible. (author)

  11. Application of a gamma spectroscopy system to the measurement of neutron cross sections necessary to the development of nuclear energy

    International Nuclear Information System (INIS)

    This work concerns the development of nuclear energy and nuclear waste management in particular. Two parts of this study can be distinguished. In the first part (theoretical), a thorium-plutonium fuel based on MOX and dedicated for PWR was investigated in order to transmute plutonium in a potentially low waste fuel cycle. It was shown that this type of fuel is not regenerative but could be used for a transition to the industrial thorium fuel cycle without building new reactors. Thanks to moderated neutron spectra and high loaded actinide mass in the core, U-233 is quickly created (∼300 kg/y) for a loss of about ∼1200 kg of fissile plutonium. In the second part (experimental), we have developed and built a new reaction chamber to measure neutron cross sections of actinides by alpha-gamma spectroscopy. This experimental device (in principle transportable) was commissioned in the high flux reactor of ILL Grenoble. Neutron flux was measured by gamma spectroscopy of irradiated Al and Co samples and was found to be of the order of 6,0. 1014 n.cm-2.s-1 (4%). By the irradiation of 11μg of Am-243 and Pu-242, corresponding capture cross sections were measured in the thermal neutron flux at 50 deg C. These are the results: 243Am(n,γ) 244fond.Am = 4,72±1,42b; 243Am(n,γ) 244totalAm = 74,8±3,25b; 242Pu (n,γ)243Pu = 22,7±1,09b. Uncertainties of the measurements are mostly due to the determination of the neutron flux, efficiency of the electronics and ambiguities related to the definition of the area under α-γ spectra. Although our measured cross sections deviate (by 10-30%) from the corresponding values widely used in evaluated data libraries such as ENDF, JEF and JENDL, in this work we have demonstrated the feasibility and principle of our experimental method. Furthermore, the value for the 243-americium capture cross-section is in very good agreement with the last two measurements done in 1975 and 1997. These facts allowed us to think of new experiments and their

  12. Gamma radiation roused lattice contraction effects investigated by Mössbauer spectroscopy in nanoparticle Mn–Zn ferrite

    International Nuclear Information System (INIS)

    Nanopowders of MnxZn1−xFe2O4 with x=0.4, 0.5 and 0.6 were synthesized using a combustion synthesis method. X-ray diffraction (XRD) patterns obtained on samples confirmed formation of monophasic cubic phase material. Lattice parameters and X-ray densities were obtained from rietvield refinement of the XRD patterns. All samples were radiated with gamma radiation with a dose of 200 Gy obtained from 60Co source. Structural and physical parameters, such as lattice constant, X-ray density and particle size, determined for as prepared samples (SA) and gamma irradiated samples (SR), showed extraordinary variations in their values. Saturation magnetizations (MS), remnant magnetization (MR) and coercive field (HC) for both sets of samples illustrated an enhancement in their values for SR samples. Investigations were carried out using Mössbauer spectroscopy to divulge structural and magnetic information of all samples. Room temperature Mössbauer spectra were fitted with five magnetic sextets and a symmetric paramagnetic doublet for the data obtained on samples except for x=0.4, SA sample. The presence of well defined doublets in the spectra of SA and SR samples is attributes of superparamagnetism, indicating the reduction in A–B superexchange interaction due to dilution of sub-lattice by Zn ions. Cation distribution at A site and B site, estimated from Mössbauer data exhibited amazing alterations which were highly stable. The variations in physical, structural and magnetic properties observed are attributed to change of Fe2+/Fe3+ and Mn+2/Mn+3 ratios in gamma-irradiated samples. - Highlights: • Nanoparticle MnxZn1−xFe2O4 (x=0.4,0.5,0.6) samples were prepared and γ-irradiated. • Reduction of lattice constant and particle size observed as the consequences of γ-exposure. • Preferred existence of Fe in +3 oxidation states. • Reduction in magnetic interaction between Fe ions due to Zn+2 dilutions. • Permanent nature of radiation induced changes

  13. [Applied Research in Grade Estimation of Surimi by Near Infrared Spectroscopy].

    Science.gov (United States)

    Wu, Hao; Chen, Wei-hua; Wang, Xi-chang; Liu, Yuan

    2015-05-01

    The feasibility of utilizing near infrared spectroscopy for estimating frozen and thawed white croaker surimi with different grades was presented in the research. First-derivative and standard normal variable transformation were used as pretreatment method, then principal component analysis was carried out on the processed datas. Establish grade estimation model on white croaker surimi with different grades by principal component analysis-mahalanobis distance pattern recognition method. Seven kinds of physicochemical indexes (moisture, protein, crude fat, salt-soluble protein, gel strength, water-holding ability and whiteness) of white croaker surimi with different grades were determinated. We came to the following conclusions. Firstly, white croaker surimi with three grade could be distinguished effectively by principal component analysis. Secondly, the model of grade estimation established by principal component analysis-mahalanobis distance pattern recognition method had better performance on frozen white croaker surimi than thawed ones, the former's comprehensive accuracy was 96. 3 % with the latter's is 83. 3%. Thirdly, the physicochemical indexes of white croaker surimi with different grades had some distinctions. The research indicated that near infrared spectroscopy could estimate the grade of white croaker surimi rapidly and nondestructively. PMID:26415435

  14. X-ray emission spectroscopy applied to glycine adsorbed on Cu(110): An atom and symmetry projected view

    Energy Technology Data Exchange (ETDEWEB)

    Hasselstroem, J.; Karis, O.; Weinelt, M. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    When a molecule is adsorbed on a metal surface by chemical bonding new electronic states are formed. For noble and transition metals these adsorption-induced states overlap with the much more intense metal d-valence band, making them difficult to probe by for instance direct photoemission. However, it has recently been shown that X-ray emission spectroscopy (XES) can be applied to adsorbate systems. Since the intermediate state involves a core hole, this technique has the power to project out the partial density of states around each atomic site. Both the excitation and deexcitation processes are in general governed by the dipole selection rules. For oriented system, it is hence possible to obtain a complete separation into 2p{sub x}, 2p{sub y} and 2p{sub z} contributions using angular resolved measurements. The authors have applied XES together with other core level spectroscopies to glycine adsorption on Cu(110). Glycine (NH{sub 2}CH{sub 2}COOH) is the smallest amino acid and very suitable to study by core level spectroscopy since it has several functional groups, all well separated in energy by chemical shifts. Its properties are futhermore of biological interest. In summary, the authors have shown that it is possible to apply XES to more complicated molecular adsorbates. The assignment of different electronic states is however not as straight forward as for simple diatomic molecules. For a complete understanding of the redistribution and formation of new electronic states associated with the surface chemical bond, experimental data must be compared to theoretical calculations.

  15. Lithium-Drifted Germanium Detectors for High Resolution Beta- and Gamma-Ray Spectroscopy

    International Nuclear Information System (INIS)

    Two types of germanium detectors have been fabricated using the lithium-ion drift technique. The first type have active volumes in excess of 6 cm3 and are primarily intended for high-energy (> 1.0 MeV) y-ray spectroscopy. The second type are large area, low capacity, windowless detectors intended for very high-resolution 6-ray and low-energy y-ray spectroscopy. Both types are operated in a vacuum at liquid nitrogen temperature (77°K). The large-volume detectors have areas greater than 6 cm2 with depletion depths in excess of 1 cm. The experimental resolution (FWHM) obtainable with these detectors is limited at low energies by the noise level of the pre-amplifier, while at high energies (>1MeV) the 1 imitation is due to amplifier instability. Typical resolutions are 3,6, and 12 keV for 0,122, 1,333and 5.0 MeV γ-rays respectively, while the photopeak efficiency ranges from approximately 75% at 122 keV to 1% at 1.333 MeV and 0. % at 5 MeV. At 5 MeV the pair-peak efficiency is ∼5%. Typical low-capacity detectors are slices (less than 5 mm thick) from the large volume detectors and have an area of 3 x 1 cm (the depletion depth). This gives a reduction in detector capacitance which results in a significant improvement in the resolution compared to that obtained with the large-volume detectors for a given pre-amplifier. At 0.122 and 1.333 MeV, resolutions of 1.9 keV and 4.1 keV respectively have been observed. Since these are essentially windowless detectors they make excellent small β-ray spectrometers. Typical resolution for the 625-keV K conversion electrons of 137Cs is less than 6 keV. These detectors are finding an increasingly wider application in both nuclear decay scheme work and in identifying the isotopic content of samples containing many isotopes. A more detailed evaluation of the properties and various applications of these two types of germanium detectors is described. (author)

  16. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

  17. Sensitive CH4 detection applying quantum cascade laser based optical feedback cavity-enhanced absorption spectroscopy.

    Science.gov (United States)

    Lang, N; Macherius, U; Wiese, M; Zimmermann, H; Röpcke, J; van Helden, J H

    2016-03-21

    We report on sensitive detection of atmospheric methane employing quantum cascade laser based optical feedback cavity-enhanced absorption spectroscopy (OF-CEAS). An instrument has been built utilizing a continuous-wave distributed feedback quantum cascade laser (cw-QCL) with a V-shaped cavity, a common arrangement that reduces feedback to the laser from non-resonant reflections. The spectrometer has a noise equivalent absorption coefficient of 3.6 × 10-9 cm-1 Hz-1/2 for a spectral scan of CH4 at 7.39 μm. From an Allan-Werle analysis a detection limit of 39 parts per trillion of CH4 at atmospheric pressure within 50 s acquisition time was found. PMID:27136874

  18. Fluorescence spectroscopy to study dissolved organic matter interactions with agrochemicals applied in Swiss vineyards.

    Science.gov (United States)

    Daouk, Silwan; Frege, Carla; Blanc, Nicolas; Mounier, Stéphane; Redon, Roland; Merdy, Patricia; Lucas, Yves; Pfeifer, Hans-Rudolf

    2015-06-01

    UV/Vis fluorescence spectroscopy was used to study the possible interactions of dissolved organic matter (DOM) with the herbicide glyphosate and copper-based fungicide used in vineyards. The study focused on the role of DOM in the transport of these micropollutants from parcels to surface waters (river, lake). Soil solution and river water samples were collected in the Lavaux vineyard area, western Switzerland. Their fluorescence excitation emission matrices (EEM) were decomposed using parallel factor (PARAFAC) analysis, and compared to their content in glyphosate and copper. PARAFAC analysis of EEM of both types of samples showed the contribution of protein-like and humic-like fluorophores. In soil water samples, complexes between fulvic-like and humic-like fluorophores of DOM, copper, and glyphosate were likely formed. In surface water, DOM-copper and glyphosate-copper interactions were observed, but not between glyphosate and DOM. PMID:25592914

  19. comparative studies on pyriproxyfen and fenoxycarb as juvenile hormones applied separately or combined with gamma radiation for controlling the mediterranean fruit fly, ceratitis capitata (Wied)

    International Nuclear Information System (INIS)

    Comparative studies on pyriproxyfen and fenoxycarb as juvenile hormones applied separately or combined with gamma radiation were carried out for controlling ceratitis capitata. Lc 50's of the two juvenile hormones, pyriproxfen and fenoxycarb, were determined against ceratitis capitata in treated diet by continuous contact of eggs and larvae using various concentrations. The Lc 50 were 32 and 140 ppm for pyriproxyfen and fenoxycarb, respectively. The resulting pupae were gamma irradiated with 90 Gy. Larval and pupal durations were insignificantly affected, pupation and adult emergence were significantly affected while adult survival was insignificantly affected when applying the two JH's. Applying pyriproxyfen alone insignificantly increased egg hatch at the concentrations used (12.5 and 25 ppm) while when fenoxycarb was applied alone egg hatch was significantly decreased at the concentration used (100 ppm). Applying both juvenile hormones each combined with gamma radiation significantly reduced egg hatch. Male mating competitiveness was significantly increased when applying pyriproxyfen at the concentration 25 Ppm. Results indicated that pyriproxyfen was more effective than fenoxycarb against the mediterranean fruit fly ceratitis capitata.1 figs., 3 tabs

  20. High spin gamma-ray coincidence spectroscopy with large detector arrays

    International Nuclear Information System (INIS)

    In-beam γ-ray spectroscopy has been used to study rapidly rotating nuclei in the rare-earth region. The experiments were performed using the high-resolution multi detector arrays ESSA30 and TESSA3 at the Nuclear Structure Facility, Daresbury Laboratories in Great Britain and the NORDBALL at the Niels Bohr Tandem Accelerator at Risoe in Denmark. The studied nuclei were produced using heavy-ion induced fusion-evaporation reactions. New techniques for the analysis of γ-γ correlation spectra were developed. These involves viewing the two-dimensional γ-γ spectrum as well as projection in both energy axes, determination of centroids and volumes of peaks and full two-dimensional Gauss fits of an arbitrarily shaped area. The data acquisition system of the NORDBALL multi detector array is presented. In two of the studied nuclei (167Lu and 163Tm) the strongly shape driving πh9/2[541]1/2- is studied. The shift to larger frequency of the neutron AB crossing in these decay sequences is not fully understood. The study of 171Re revealed a second backbend of the [402]5/2+ band. The observed bandcrossings are interpreted using the CSM and three-band mixing calculations. The study of 171,172W revealed five new bands and although these nuclei are expected to be stably deformed the small differences in the formation showed to be crucial in order to reproduce data well. (au)

  1. Neutron Spectroscopy of the Alpha and Gamma Forms of Nylon-6 Polymer

    Science.gov (United States)

    Papanek, Peter; Fischer, John E.; Murthy, N. S.

    1998-03-01

    The polyamide nylon-6 crystallizes in two different forms, α and γ, characterized by different chain conformations, and different arrangement of hydrogen bonds between chains. We have performed inelastic neutron scattering experiments to study the effects of H-bonding on lattice dynamics in both forms. Selectively deuterated and stretch oriented samples were used in order to identify the phonon modes and determine their polarization with respect to chain axes. Two complementary techniques, the filter-analyzer and time-of-flight (TOF) spectroscopy were employed. We have found that certain modes are similar in both α and γ fibers, however there are also significant differences in the 12--40 meV range, and in the frequencies of amide VI and amide VII modes. TOF spectra of both forms show broad low-frequency Boson peaks also at slightly different positions. The experimental results will be compared with semiempirical and ab initio calculations for a pair of chains at different relative orientations, and the relationship between the strength of H-bonds and amide vibrations will be discussed.

  2. Estimation of the absorbed dose in gamma irradiated food containing bone by electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    The use of electron spin resonance (ESR) spectroscopy to accurately evaluate the absorbed dose to radiationprocessed bones (and thus meats) is examined. The exposure of foodstuffs containing bone to a dose of ionizing radiation results in the formation of long lived free radicals which give rise to characteristics ESR signals. The yield of radicals was found to be proportional to absorbed dose. Additive re-irradiation of previously irradiated bone was used to estimate the absorbed dose in the irradiated chicken bone. Simple non-linear rational equation was found to fit to the data and yields good dose estimates for irradiated bone in the range of doses (1.0 - 5.0 kGy). Decay of the ESR signal intensity was monitored at different dose levels (2.0 and 7.0 kGy) up to 22 days. The absorbed dose in irradiated chicken (2.Om 3.0 and 6.0 kGy) was assessed at 2, 6 and 12 days after irradiation. Relatively good results were obtained when measurements were made within the following days (up to 12 days) after irradiation. The ability of the dose additive method to provide accurate dose assessments is tested here

  3. Impact of detector efficiency and energy resolution on gamma-ray background rejection in mobile spectroscopy and imaging systems

    International Nuclear Information System (INIS)

    The presence of gamma-ray background significantly reduces detection sensitivity when searching for radioactive sources in the field, and the systematic variability in the background will limit the size and energy resolution of systems that can be used effectively. An extensive survey of the background was performed using both sodium iodide and high-purity germanium. By using a bivariate negative binomial model for the measured counts, these measurements can be resampled to simulate the performance of a detector array of arbitrary size and resolution. The response of the system as it moved past a stationary source was modeled for spectroscopic and coded aperture imaging algorithms and used for source injection into the background. The performance of both techniques is shown for various sizes and resolutions, as well as the relative performance for sodium iodide and germanium. It was found that at smaller detector sizes or better energy resolution, spectroscopy has higher detection sensitivity than imaging, while imaging is better suited to larger or poorer resolution detectors

  4. Assessment of the toxicity level of gamma-irradiated snake (Naja naja oxiana) venom by photoacoustic spectroscopy

    International Nuclear Information System (INIS)

    Immunization is the only answer to the challenge of the diseases for which it is extremely difficult to institute timely and proper treatment following the inset. Various antigenic agents responsible for such diseases are used for the purpose of immunization to overcome this difficulty. To make safe use of the antigens it is required to reduce their toxicity level keeping the antigenicity intact and develop a suitable way to detect it. To ensure this, toxoids are produced from the toxic antigens by using different physical and chemical methods. Snake venoms are some important antigens which deserve more attention to be used for immunization because bites by poisonous snakes require instant treatment which is difficult to install. Toxoids used in the present study were produced by irradiating oxus cobra (Naja naja oxiana) venom under cobalt-60 gamma-ray source. The toxocity level of thus produced venom toxoid was assessed by photoacoustic (PA) spectroscopy. In support of the PA observations, optical absorption and fluorescence spectra of the venom in solution were also studied. Percentile change in PA signal intensity was taken as the parameter for toxocity level which was then correlated to the percentile residual toxocity of the venom obtained by direct method of injecting the venom in mice. Efforts were also made to find out the possible effects of the radiation on the venom. (author). 29 refs., 7 figs

  5. Impact of detector efficiency and energy resolution on gamma-ray background rejection in mobile spectroscopy and imaging systems

    Energy Technology Data Exchange (ETDEWEB)

    Aucott, Timothy J., E-mail: Timothy.Aucott@SRS.gov [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Bandstra, Mark S. [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Negut, Victor; Curtis, Joseph C. [University of California, Berkeley, Department of Nuclear Engineering, Berkeley, CA (United States); Meyer, Ross E.; Chivers, Daniel H. [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Vetter, Kai [University of California, Berkeley, Department of Nuclear Engineering, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States)

    2015-07-21

    The presence of gamma-ray background significantly reduces detection sensitivity when searching for radioactive sources in the field, and the systematic variability in the background will limit the size and energy resolution of systems that can be used effectively. An extensive survey of the background was performed using both sodium iodide and high-purity germanium. By using a bivariate negative binomial model for the measured counts, these measurements can be resampled to simulate the performance of a detector array of arbitrary size and resolution. The response of the system as it moved past a stationary source was modeled for spectroscopic and coded aperture imaging algorithms and used for source injection into the background. The performance of both techniques is shown for various sizes and resolutions, as well as the relative performance for sodium iodide and germanium. It was found that at smaller detector sizes or better energy resolution, spectroscopy has higher detection sensitivity than imaging, while imaging is better suited to larger or poorer resolution detectors.

  6. In situ Cell for Mossbauer Spectroscopy between 5 and 800 K in Applied Magnetic Fields

    DEFF Research Database (Denmark)

    Bødker, Franz; Mørup, Steen

    Mossbauer studies in large applied magnetic fields. The samples can also be separated from the gas-manifold for long term storage in a controlled enviroment and for studies by other experimental techniques such as magnetic measurements. The application of this system is illustrated by results of...

  7. Development of gamma spectroscopy employing NaI(Tl) detector 3 inch x 3 inch and readout electronic of flash-ADC/FPGA-based technology

    Energy Technology Data Exchange (ETDEWEB)

    Hai, Vo Hong [HCMC-National Univ., Hochiminh City (Viet Nam). Inst. of Nuclear Physics; Ton Duc Thang Univ., Ho Chi Minh City (Viet Nam). Div. of Nuclear Physics; Hung, Nguyen Quoc [HCMC-National Univ., Hochiminh City (Viet Nam). Inst. of Nuclear Physics; Khai, Bui Tuan [Osaka Univ. (Japan). Dept. of Physics

    2015-05-15

    n this article the development of a gamma spectroscopy system is described using a scintillation detector NaI(Tl) of 3 inch x 3 inch. The readout electronic for the spectroscopy is built from the fast analog-digital conversion of Flash Analog-Digital Converter (Flash-ADC) 250 MHz - 8 bits resolution, and the embedded Field-Programmable Gate Array (FPGA) technology. The embedded VHSIC Hardware Description Language (VHDL) code for FPGA is built in such a way that it works as a multi channel analyser (MCA) with 4096 Digital Charge Integration (DCI) channels. A pulse generator with frequency varying from Hz up to 12 kHz is used to evaluate the time response of the system. Two standard radioisotope sources of {sup 133}Ba and {sup 152}Eu with multi gamma energies ranging from several tens keV to MeV are used to evaluate the linearity and energy resolution of the system.

  8. Development of gamma spectroscopy employing NaI(Tl) detector 3 inch x 3 inch and readout electronic of flash-ADC/FPGA-based technology

    International Nuclear Information System (INIS)

    n this article the development of a gamma spectroscopy system is described using a scintillation detector NaI(Tl) of 3 inch x 3 inch. The readout electronic for the spectroscopy is built from the fast analog-digital conversion of Flash Analog-Digital Converter (Flash-ADC) 250 MHz - 8 bits resolution, and the embedded Field-Programmable Gate Array (FPGA) technology. The embedded VHSIC Hardware Description Language (VHDL) code for FPGA is built in such a way that it works as a multi channel analyser (MCA) with 4096 Digital Charge Integration (DCI) channels. A pulse generator with frequency varying from Hz up to 12 kHz is used to evaluate the time response of the system. Two standard radioisotope sources of 133Ba and 152Eu with multi gamma energies ranging from several tens keV to MeV are used to evaluate the linearity and energy resolution of the system.

  9. Transmission electron microscopy and energy dispersive x-ray spectroscopy studies of Pt-Re/[gamma]-Al[sub 2]O[sub 3] catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z.; Fryer, J.R.; Park, C.; Stirling, D.; Webb, G. (Univ. of Glasgow (United Kingdom))

    1994-08-01

    A series of Pt/[gamma]-Al[sub 2]O[sub 3], Re/[gamma]-Al[sub 2]O[sub 3], and Pt-Re/[gamma]-Al-O[sub 3] catalysts have been studied by transmission electron microscopy and energy dispersive X-ray spectroscopy. It has been shown that rhenium was not alloyed with platinum, but widely dispersed on the surface of alumina. Two types of platinum were found: (i) three-dimensional metallic particles, and (ii) small particles consisting of a few platinum atoms. Some aggregation of the platinum particles occurred during use of the catalysts in the reforming of octane. It is suggested that the interaction of rhenium with the alumina support and therefore the modification to the platinum play an essential role in promoting the enhanced stability and selectivity of these catalysts to cycloalkanes and aromatics in reforming reactions. 40 refs., 13 figs., 2 tabs.

  10. Investigation of hyperfine interactions in pure silicon and NTD silicon by means of perturbed angular {gamma}-{gamma} correlation spectroscopy; Investigacao de interacoes hiperfinas em silicio puro e silicio NTD pela tecnica de correlacao angular {gamma}-{gamma} perturbada

    Energy Technology Data Exchange (ETDEWEB)

    Cordeiro, Moacir Ribeiro

    2007-07-01

    III the present work, a microscopic investigation of hyperfine interactions in single crystal silicon samples was carried out by means of Perturbed Angular {gamma} -{gamma} correlation technique (PAC), which is based in hyperfine interactions. In order to achieve these measurements, it was used {sup 111} In {yields} {sup 111}Cd radioactive probe nuclei, which decay through the well known {gamma} cascade 171-245 keV with an intermediate level of 245 keV ( I 5{sup +}/2, Q = 0.83b, T{sub 1/2} = 84.5 ns). The samples were prepared using different probe nuclei insertion methods, making possible to increase our understanding on the impact generated by each of these techniques in PAC measurements. Ion implantation, diffusion and evaporation were carefully investigated giving emphasis on its characteristics and particularities. Then, it was made a study about the concentration of intrinsic defects as function of severe annealing processes. Finally, a comparative analysis was made for all these probe nuclei insertion methods. This work also accomplished PAC measurements in single crystal silicon doped with phosphorus by means of Neutron Transmutation Doping (NTD) method, carried out in a research nuclear reactor. The extremely high doping uniformity allied to the nonexistence of previous measurements in these materials emphasize the importance of the results obtained. These results are then compared with literature results for samples doped by conventional methods presenting the respective conclusions. (author)

  11. IR double-resonance spectroscopy applied to the 4-aminophenol(H2O)1 cluster

    Science.gov (United States)

    Gerhards, M.; Unterberg, C.

    2001-04-01

    The IR double-resonance techniques IR/R2PI (infrared/resonant 2-photon ionization), IR/PIRI (infrared-photo-induced Rydberg ionization) and IR-photodissociation spectroscopy are valuable tools to investigate structure, vibrations, and dynamical processes of neutral and ionic hydrogen-bonded clusters containing aromatic molecules. In this paper we report on the application of the IR double-resonance techniques to determine the NH and OH stretching vibrations of 4-aminophenol and 4-aminophenol(H2O)1, both in the neutral (S0) and ionic (D0) ground state. All vibrational frequencies obtained for 4-aminophenol and the cluster are compared with the values obtained from ab initio and DFT calculations. In the S0 state, a trans-linear arrangement of 4-aminophenol(H2O)1 is obtained containing an O-H..O hydrogen bond. In the D0 state an overlay of two spectra can be observed resulting from the trans-linear structure and a second structure which contains a N-H..O hydrogen bond. The observation of these two structures within the ion is an interesting example of a rearrangement reaction in the ionic state.

  12. Auger electron spectroscopy applied to inner shell ionization by fast charged particles

    International Nuclear Information System (INIS)

    Until recently, inner shell ionization by charged particle impact was studied almost exclusively through the use of x-ray spectroscopy. This method is limited in accuracy, however, for ionization of inner shells where the fluorescence yield is small. For K-shell ionization of elements with atomic number less than about ten the fluorescence yield can be considered negligible and Auger electron emission cross section provide direct information regarding the ionization cross section. The ionization cross sections determined in this way are accurate to approximately 20 percent whereas x-ray measurements may be uncertain by a factor of five or more due to uncertainties in fluorescence yields. In addition to ionization cross sections, Auger emission spectra provide information regarding multiple ionization, effects of molecular binding on inner shell ionization and, when coupled with x-ray measurements, provide fluorescence yields as a function of the final state of the target atom. These points will be illustrated for ionization by fast protons along with some results for heavier incident particles

  13. EPR spectroscopy applied to the study of the TEMPO mediated oxidation of nanocellulose.

    Science.gov (United States)

    Buffa, Juan M; Grela, María Alejandra; Aranguren, Mirta I; Mucci, Verónica

    2016-01-20

    Two different methods of pH control were used in the synthesis of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized cellulose nanocrystals (CNC) and the reaction kinetics and degree of oxidation were investigated. In method I the media pH was controlled by addition of NaOH solution. The effect of the oxidant concentration (sodium hypochloride, NaClO) on the final degree of oxidation and crystallinity of the samples was investigated. Conditions for obtaining an optimum balance between high crystallinity and degree of oxidation were selected from those results. In method II, pH was fixed by using a buffer solution. Electron spin resonance (ESR) spectroscopy offered direct information of the decay of TEMPO concentration under these conditions. The kinetics of the reaction was determined, finding a direct correlation between these results and those corresponding to the decay of the NaClO concentration and the advance of the CNC degree of oxidation. Differences found between the two methods were analyzed. PMID:26572408

  14. [Clustering analysis applied to near-infrared spectroscopy analysis of Chinese traditional medicine].

    Science.gov (United States)

    Liu, Mu-qing; Zhou, De-cheng; Xu, Xin-yuan; Sun, Yao-jie; Zhou, Xiao-li; Han, Lei

    2007-10-01

    The present article discusses the clustering analysis used in the near-infrared (NIR) spectroscopy analysis of Chinese traditional medicines, which provides a new method for the classification of Chinese traditional medicines. Samples selected purposely in the authors' research to measure their absorption spectra in seconds by a multi-channel NIR spectrometer developed in the authors' lab were safrole, eucalypt oil, laurel oil, turpentine, clove oil and three samples of costmary oil from different suppliers. The spectra in the range of 0.70-1.7 microm were measured with air as background and the results indicated that they are quite distinct. Qualitative mathematical model was set up and cluster analysis based on the spectra was carried out through different clustering methods for optimization, and came out the cluster correlation coefficient of 0.9742 in the authors' research. This indicated that cluster analysis of the group of samples is practicable. Also it is reasonable to get the result that the calculated classification of 8 samples was quite accorded with their characteristics, especially the three samples of costmary oil were in the closest classification of the clustering analysis. PMID:18306778

  15. Comparison of motion correction techniques applied to functional near-infrared spectroscopy data from children

    Science.gov (United States)

    Hu, Xiao-Su; Arredondo, Maria M.; Gomba, Megan; Confer, Nicole; DaSilva, Alexandre F.; Johnson, Timothy D.; Shalinsky, Mark; Kovelman, Ioulia

    2015-12-01

    Motion artifacts are the most significant sources of noise in the context of pediatric brain imaging designs and data analyses, especially in applications of functional near-infrared spectroscopy (fNIRS), in which it can completely affect the quality of the data acquired. Different methods have been developed to correct motion artifacts in fNIRS data, but the relative effectiveness of these methods for data from child and infant subjects (which is often found to be significantly noisier than adult data) remains largely unexplored. The issue is further complicated by the heterogeneity of fNIRS data artifacts. We compared the efficacy of the six most prevalent motion artifact correction techniques with fNIRS data acquired from children participating in a language acquisition task, including wavelet, spline interpolation, principal component analysis, moving average (MA), correlation-based signal improvement, and combination of wavelet and MA. The evaluation of five predefined metrics suggests that the MA and wavelet methods yield the best outcomes. These findings elucidate the varied nature of fNIRS data artifacts and the efficacy of artifact correction methods with pediatric populations, as well as help inform both the theory and practice of optical brain imaging analysis.

  16. UV-VIS Spectroscopy Applied to Stratospheric Chemistry, Methods and Results

    Energy Technology Data Exchange (ETDEWEB)

    Karlsen, K.

    1996-03-01

    This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Numerous observations and modeling have shown with a very high degree of certainty that the man-made emissions of chlorofluorocarbons (CFC) and halons are responsible for the Antarctica ozone hole. It is also evident that the ozone layer of the Northern Hemisphere has suffered a certain decline over the last 10-15 years, possibly because of CFC and halons. 20-30% of the observed reduction is ascribed to coupled chlorine and bromine chemistry via a catalytic cycle resulting in the net conversion of 2O{sub 3} to 3O{sub 2}. But the details are not fully understood. The author plans to assemble a UV-VIS spectrometer for measuring the species OClO and BrO and to compare and discuss measured diurnal variations of OClO and BrO with model calculations. The use of Differential Optical Absorption Spectroscopy (DOAS) is discussed and some results from late 1995 presented. 6 refs., 2 figs.

  17. The influence of ruthenium on the magnetic properties of gamma-Fe sub 2 O sub 3 (maghemite) studied by Moessbauer spectroscopy

    CERN Document Server

    Helgason, O; Berry, F J; Mosselmans, F

    2003-01-01

    Ruthenium-doped gamma-Fe sub 2 O sub 3 has been synthesized and examined by x-ray powder diffraction, XANES, EXAFS and by sup 5 sup 7 Fe Moessbauer spectroscopy. Ruthenium K-edge x-ray absorption spectroscopy shows that ruthenium adopts a fully occupied octahedral site in the spinel related gamma-Fe sub 2 O sub 3 structure as Ru sup 4 sup +. The sup 5 sup 7 Fe Moessbauer spectra recorded in the presence of a longitudinal magnetic field of 6 T confirmed the octahedral coordination of the tetravalent ions and canting angles for the Fe sup 3 sup + ions were determined as 24 deg. for those in octahedral sites and 33 deg. for those in tetrahedral sites. The sup 5 sup 7 Fe Moessbauer spectra recorded in situ from ruthenium-doped gamma-Fe sub 2 O sub 3 showed parameters typical of maghemite up to 600 K but with a magnetic hyperfine field distribution suggesting an inhomogeneous distribution of ruthenium within particles of varied size around about 15 nm. At 700 K a phase transition from gamma-Fe sub 2 O sub 3 to alp...

  18. Gravity-mode period spacings as seismic diagnostic for a sample of gamma Doradus stars from Kepler space photometry and high-resolution ground-based spectroscopy

    CERN Document Server

    Van Reeth, T; Aerts, C; Papics, P I; Triana, S A; Zwintz, K; Degroote, P; Debosscher, J; Bloemen, S; Schmid, V S; De Smedt, K; Fremat, Y; Fuentes, A S; Homan, W; Hrudkova, M; Karjalainen, R; Lombaert, R; Nemeth, P; Oestensen, R; Van De Steene, G; Vos, J; Raskin, G; Van Winckel, H

    2015-01-01

    Gamma Doradus stars (hereafter gamma Dor stars) are gravity-mode pulsators of spectral type A or F. Such modes probe the deep stellar interior, offering a detailed fingerprint of their structure. Four-year high-precision space-based Kepler photometry of gamma Dor stars has become available, allowing us to study these stars with unprecedented detail. We selected, analysed, and characterized a sample of 67 gamma Dor stars for which we have Kepler observations available. For all the targets in the sample we assembled high-resolution spectroscopy to confirm their F-type nature. We found fourteen binaries, among which four single-lined binaries, five double-lined binaries, two triple systems and three binaries with no detected radial velocity variations. We estimated the orbital parameters whenever possible. For the single stars and the single-lined binaries, fundamental parameter values were determined from spectroscopy. We searched for period spacing patterns in the photometric data and identified this diagnosti...

  19. Impact-collision ion scattering spectroscopy applied to the determination of atomic surface structure

    International Nuclear Information System (INIS)

    The technique of impact collision ion scattering spectroscopy (ICISS) was used to investigate the atomic structure and low energy ion scattering dynamics from various surfaces. A new formalism for calculating the three-dimensional cross section for an ion to scatter sequentially and classically from two atoms has been developed. This method can be used to assist in the interpretation of ICISS data in terms of quantitative surface-structure models. In an ICISS investigation of the Ag(110) surface, a surface flux peak analysis demonstrated that the surface was not a complete monolayer, but rather contained 10-15% random vacancies. Subsurface Li+ scattering results confirmed the oscillatory relaxation of the first two atomic layers of the surface, with Δ12 = -7.5% and Δ23 = 4.0%. Modeling of the neutralization mechanism for the He+ scattering gave a best fit time-dependent Auger neutralization time constant of 0.84 ± 0.08 fs. A neutralization study of 5 keV He+ ions scattered from Au adatoms on the Si(111)-√3 x √3-Au surface showed the He+ ICISS data contained false shadowing features that were actually the result of local neutralization effects. A detailed examination of the Si(111)-√3 x √3-Ag surface was also made. The 5 keV Li+ ICISS data gave evidence for Ag island formation at single monolayer coverages of silver, while the LEED, AES and LEIS data showed that at relatively high coverages of Ag (35 ML) small areas of √3 x √3 character were still present

  20. Time resolved spectroscopy of SGR J1550–5418 bursts detected with Fermi/gamma-ray burst monitor

    Energy Technology Data Exchange (ETDEWEB)

    Younes, G. [Universities Space Research Association, 6767 Old Madison Pike, Suite 450, Huntsville, AL 35806 (United States); Kouveliotou, C.; Collazzi, A. [Astrophysics Office, ZP 12, NASA-Marshall Space Flight Center, Huntsville, AL 35812 (United States); Van der Horst, A. J.; Watts, A. L.; Huppenkothen, D.; Van der Klis, M.; Van Putten, T. [Astronomical Institute " Anton Pannekoek," University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Granot, J. [Department of Natural Sciences, The Open University of Israel, 1 University Road, P.O. Box 808, Raánana 43537 (Israel); Bhat, P. N.; Gorgone, N. [University of Alabama in Huntsville CSPAR, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Gehrels, N.; Mcenery, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Göğüş, E.; Kaneko, Y.; Lin, L. [Sabancı University, Orhanlı-Tuzla, İstanbul 34956 (Turkey); Gruber, D.; Von Kienlin, A. [Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, Postfach 1312, D-85748 Garching (Germany); Grunblatt, S. [University of Hawaii at Manoa, 2500 Campus Road, Honolulu, HI 96822 (United States); and others

    2014-04-10

    We report on a time-resolved spectroscopy of the 63 brightest bursts of SGR J1550–5418, detected with the Fermi/Gamma-ray Burst Monitor during its 2008-2009 intense bursting episode. We performed spectral analysis down to 4 ms timescales to characterize the spectral evolution of the bursts. Using a Comptonized model, we find that the peak energy, E {sub peak}, anti-correlates with flux, while the low-energy photon index remains constant at ∼ – 0.8 up to a flux limit F ≈ 10{sup –5} erg s{sup –1} cm{sup –2}. Above this flux value, the E {sub peak}–flux correlation changes sign, and the index positively correlates with the flux reaching ∼1 at the highest fluxes. Using a two blackbody model, we find that the areas and fluxes of the two emitting regions correlate positively. Further, we study here for the first time the evolution of the temperatures and areas as a function of flux. We find that the area–kT relation follows the lines of constant luminosity at the lowest fluxes, R {sup 2}∝kT {sup –4}, with a break at the higher fluxes (F > 10{sup –5.5} erg s{sup –1} cm{sup –2}). The area of the high-kT component increases with the flux while its temperature decreases, which we interpret as being due to an adiabatic cooling process. The area of the low-kT component, on the other hand, appears to saturate at the highest fluxes, toward R {sub max} ≈ 30 km. Assuming that crust quakes are responsible for soft gamma repeater (SGR) bursts and considering R {sub max} as the maximum radius of the emitting photon-pair plasma fireball, we relate this saturation radius to a minimum excitation radius of the magnetosphere, and we put a lower limit on the internal magnetic field of SGR J1550–5418, B {sub int} ≳ 4.5 × 10{sup 15} G.

  1. Measurement of radium - 226 in rock phosphate used as low cost fertilizer using gamma spectroscopy

    International Nuclear Information System (INIS)

    This study was carried out to determine the concentration of radium - 226 in rock phosphate (used as low cost fertilizer), soil and plant. Two types of rock phosphates were examined, namely, Uro and kurun area in the Nuba mountains located in the western part of the sudan. The work included the determination of 226 Ra levels in soil after applying different concentration of rock phosphate in pot experiments. The plant used was Abu sabien a sorghum which used for the animal feed. 226 Ra in the soil using 20 g/pot (1000 kg/fed). of rock phosphate was found to be 88 and 104 Bq/kg for and 45 and 72 Bq/kg for kurun for season one and three respectively. As for the plant the concentration was found to be 1.2 and 1.4 Bq/kg for Uro and 0.4 and 0.6 Bq/kg for kurun for the first and third seasons respectively. The transfer factor of 226 Ra from soil to plant was estimated to be (0.01). The concentration of 226 Ra in the plant was found to be below the recommended values of contamination. 4 figs

  2. X-ray and Gamma-ray Spectroscopy of Solids under Pressure

    Energy Technology Data Exchange (ETDEWEB)

    None

    2000-03-01

    This report describes our recent synchrotrons x-ray absorption fine structure (XAFS) measurements on a number of systems that undergo pressure induced changes in local structure at high pressure. The reader should also refer to the accompanying renewal proposal for a more in-depth discussion of the general scope of this program, and its relevance to condensed matter science. We merely state that the methods here are aimed at using XAFS to probe the various phenomena that are caused by high pressure, especially including various structural, and/or electronic, changes or transitions. Our general technique is based upon a pressure cell which utilizes scintered boron carbide anvils, since diamond anvils generally produce Bragg glitches which spoil the high quality XAFS necessary for precision structural measurements. Sample pressure is determined at the beam-line by measuring and analyzing, via XAFS, the compression of some cubic material contained within the sample chamber. Recently we have extended this work to 77 K using helium gas for the applied force, rather than hydraulic oil. This report period has been productive. The increased flux available at the Stanford Synchrotrons Radiation Laboratory (SSRL) has permitted our going to smaller beams, on the order of 300 pm in diameter, for precision probing of the sample region. At the same time we have received ample amounts of beam time at SSRL, in part because of the high rating of our latest user proposal. We also were invited to share some of the beam time at the National Synchrotron Light Source (NSLS) assigned to the group of our collaborator, E. A. Stern. Below we describe in some detail our recent work. Some of the pending papers are reports on systems that have been under study for some time and have been described in past progress reports and, as such, need not be described again here.

  3. First Year PIDDP Report on gamma-ray and x-ray spectroscopy: X-ray remote sensing and in situ spectroscopy for planetary exploration missions and gamma-ray remote sensing and in situ spectroscopy for planetary exploration missions

    Science.gov (United States)

    Mahdavi, M.; Giboni, K. L.; Vajda, S.; Schweitzer, J. S.; Truax, J. A.

    1994-01-01

    Detectors that will be used for planetary missions must have their responses calibrated in a reproducible manner. In addition, it is important to characterize a detector system at uneven portions of its life cycle, for example after exposure to different amounts of radiation. A calibration and response characterization facility has been constructed at Schlumberger-Doll Research for all types of gamma- and x-ray detectors that may be used for planetary measurement. This facility is currently being tested. Initial use is expected for the MARS 94 detectors. The facility will then also be available for calibrating other detectors as well as arrays of detectors such as the NEAR detector with its central Nal(TI) crystal surrounded with a large BGO crystal. Cadmium telluride detectors are investigated for applications in space explorations. These detectors show an energy resolution of 5 keV for the 122 keV 57Co line. Earlier reported polarization effects are not observed. The detectors can be used at temperatures up to 100 C, although with reduced energy resolution. The thickness of standard detectors is limited to 2 mm. These detectors become fully efficient at bias voltages above 200 V. Initial results for a 1 cm thick detector show that the quality of the material is inferior to the thinner standard detectors and hole trapping affects the pulse height. A detailed characterization of the detector is in progress. Prototypes of photomultipliers based on a Channel Electron Multiplier (CEM) are being built to study their performance. Such photomultipliers promise better timing characteristics and a higher dynamic range while being more compact and of lower in weight.

  4. X-ray spectroscopy applied to radiation shielding calculation in mammography

    International Nuclear Information System (INIS)

    The protective shielding design of a mammography facility requires the knowledge of the scattered radiation by the patient and image receptor components. The shape and intensity of secondary x-ray beams depend on the kVp applied to the x-ray tube, target/filter combination, primary x-ray field size, and scattering angle. Currently, shielding calculations for mammography facilities are performed based on scatter fraction data for Mo/Mo target/filter, even though modern mammography equipment is designed with different anode/filter combinations. In this work we present scatter fraction data evaluated based on the x-ray spectra produced by a Mo/Mo, Mo/Rh and W/Rh target/filter, for 25, 30 and 35 kV tube voltages and scattering angles between 30 and 165 deg. Three mammography phantoms were irradiated and the scattered radiation was measured with a CdZnTe detector. The primary x-ray spectra were computed with a semiempirical model based on the air kerma and HVL measured with an ionization chamber. The results point out that the scatter fraction values are higher for W/Rh than for Mo/Mo and Mo/Rh, although the primary and scattered air kerma are lower for W/Rh than for Mo/Mo and Mo/Rh target/filter combinations. The scatter fractions computed in this work were applied in a shielding design calculation in order to evaluate shielding requirements for each of these target/filter combinations. Besides, shielding requirements have been evaluated converting the scattered air kerma from mGy/week to mSv/week adopting initially a conversion coefficient from air kerma to effective dose as 1 Sv/Gy and then a mean conversion coefficient specific for the x-ray beam considered. Results show that the thickest barrier should be provided for Mo/Mo target/filter combination. They also point out that the use of the conversion coefficient from air kerma to effective dose as 1 Sv/Gy is conservatively high in the mammography energy range and overestimate the barrier thickness

  5. FTIR-ATR spectroscopy applied to quality control of grape-derived spirits.

    Science.gov (United States)

    Anjos, Ofélia; Santos, António J A; Estevinho, Letícia M; Caldeira, Ilda

    2016-08-15

    The Fourier transform infrared (FTIR) spectroscopic method with attenuated total reflectance (ATR) was used for predicting the alcoholic strength, the methanol, acetaldehyde and fusel alcohols content of grape-derived spirits. FTIR-ATR spectrum in the mid-IR region (4000-400cm(-1)) was used for the quantitative estimation by applying partial least square (PLS) regression models and the results were correlated with those obtained from reference methods. In the developed method, a cross-validation with 50% of the samples was used for PLS analysis along with a validation test set with 50% of the remaining samples. Good correlation models with a great accuracy were obtained for methanol (r(2)=99.4; RPD=12.8), alcoholic strength (r(2)=97.2; RPD=6.0), acetaldehyde (r(2)=98.2; RPD=7.5) and fusel alcohols (r(2) from 97.4 to 94.1; RPD from 6.2 to 4.1). These results corroborate the hypothesis that FTIR-ATR is a useful technique for the quality control of grape-derived spirits, whose practical application may improve the efficiency and quickness of the current laboratory analysis. PMID:27006210

  6. Study of 16O-induced deep inelastic nuclear reactions on 27Al, 48Ti, and 58Ni by spectroscopy of the gamma radiation from the reaction products

    International Nuclear Information System (INIS)

    The present thesis deals with the spectroscopy of the gamma radiation from the reaction fragments after binary reactions in the systems 16O + 27Al, 48Ti, and 58Ni at incident energies from 90 to 100 MeV, i.e. far above the Coulomb threshold. ΔE-E telescopes, which were located at 350 to the beam direction, detected the projectile-like fragments and defined the reaction channel and the scattering plane. In coincidence to this the gamma quanta in a 120-cm3-Ge(Li)-diode and a 27 x 33-cm-NaI-spectrometer were observed. The gamma spectra are equal to those observed hitherto in fusion reactions except for the high energetic gamma lines from the ejectiles, which are raised from the gamma continuum of the heavy fragments. From the spectroscoped gamma radiation for the light as for the heavy fragments the excitation energy, the value of the fragment angular momentum, as well as the occupation of the magnetic sublevels could be determined. The hard projectile 16O transfers the dissipated energy and the angular momentum transferred by the spin of the fragments nearly completely into the residue nucleus. The probability for the observation of a ground state transition in one of the heavy fragments extends to (0.85 +- 0.10) per carbon ejectile in the system 16O + 48Ti. The residue nucleus distribution corresponds to that expected by the statistical model from the decay of the compound-nucleus 52Cr belonging to the ejectile 12C, the excitation energy of which corresponds to the reaction Q-value. (orig./HSI)

  7. Effect of gamma-rays on inherited sterility and sperm transfer in Ephestia kuehniella with genetic sexing applied

    Czech Academy of Sciences Publication Activity Database

    Marec, František; Koudelová, Jana

    1998-01-01

    Roč. 71, - (1998), s. 39. [ FAO /IAEA International Conference on area-wide control of insect pests integrating the sterile insect and related nuclear and other techniques. 28.05.1998-02.06.1998, Penang] Keywords : Ephestia kuehniela * gamma-rays Subject RIV: EB - Genetics ; Molecular Biology

  8. In situ gamma-spectroscopy. A technology for the integrated preparation of contamination registers for buildings and site areas

    International Nuclear Information System (INIS)

    In the context of decommissioning of nuclear facilities, the assigned buildings and site areas must be inspected for their contamination, in particular for free release by the nuclear authority. Whereas at least two different measuring techniques were required for that until now, RWE NUKEM has developed and qualified a single process for this task. Based on a 3D model of the facility, the location of measuring points, the measuring results and proposals for decontamination measures to be taken can be generated on base of a limited number of measurements. The process was industrially applied for the first time in the dismantling of a former fuel fabrication plant in Hanau, Germany. The measuring technique is applicable for the activity measurement of gamma-emitters, e.g. Co-60 and Cs-137, as well as alpha emitters, e.g. U-235 and Am-241, via related gamma lines. Thus the existing nuclide spectra of nuclear power stations, of Uranium processing facilities and other nuclear installations can be measured. The nuclides not being measured directly are usually calculated through nuclide vectors and detectable nuclides. The measuring system consists of one Ge-semiconductor detector, cooled with liquid Nitrogen. The measuring signals are routed via a pre and a main amplifier and an analogous/digital converter to the multi channel analyser and are analyzed by a PC. The paper gives as an application the decommissioning of a fuel fabrication plant. Site models are discussed as well as decommissioning process in two steps: Step 1 - Free release of building structures and Step 2 - Free release of the site. In conclusion, in situ measurements - supported by the soil sorting gate, Marinelli measurements and borehole sampling - have proven to be an effective approach for the free release of surface structures of the former fuel element fabrication plant at Hanau. These surfaces include inner walls of rooms as well as the outside surface of buildings and layers of soil. The

  9. Defect Measurements of CdZnTe Detectors Using I-DLTS, TCT, I-V and Gamma-ray Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gul,R.

    2008-08-11

    In this work we measured the crystal defect levels and tested the performance of CdZnTe detectors by diverse methodologies, viz., Current Deep Level Transient Spectroscopy (I-DLTS), Transient Current Technique (TCT), Current and Capacitance versus Voltage measurements (I-V and C-V), and gamma-ray spectroscopy. Two important characteristics of I-DLTS technique for advancing this research are (1) it is applicable for high-resistivity materials (>10{sup 6} {Omega}-cm), and, (2) the minimum temperature for measurements can be as low as 10 K. Such low-temperature capability is excellent for obtaining measurements at shallow levels. We acquired CdZnTe crystals grown by different techniques from two different vendors and characterized them for point defects and their response to photons. I-DLTS studies encompassed measuring the parameters of the defects, such as the energy levels in the band gap, the carrier capture cross-sections and their densities. The current induced by the laser-generated carriers and the charge collected (or number of electrons collected) were obtained using TCT that also provides the transport properties, such as the carrier life time and mobility of the detectors under study. The detector's electrical characteristics were explored, and its performance tested using I-V, C-V and gamma-ray spectroscopy.

  10. Characterization of low-pressure microwave and radio frequency discharges in oxygen applying optical emission spectroscopy and multipole resonance probe

    International Nuclear Information System (INIS)

    Optical emission spectroscopy (OES) and multipole resonance probe (MRP) are adopted to characterize low-pressure microwave (MW) and radio frequency (RF) discharges in oxygen. In this context, both discharges are usually applied for the deposition of permeation barrier SiOx films on plastic foils or the inner surface of plastic bottles. For technological reasons the MW excitation is modulated and a continuous wave (cw) RF bias is used. The RF voltage produces a stationary low-density plasma, whereas the high-density MW discharge is pulsed. For the optimization of deposition process and the quality of the deposited barrier films, plasma conditions are characterized using OES and MRP. To simplify the comparison of applied diagnostics, both MW and RF discharges are studied separately in cw mode. The OES and MRP diagnostic methods complement each other and provide reliable information about electron density and electron temperature. In the MW case, electron density amounts to ne = (1.25 ± 0.26) × 1017 m−3, and kTe to 1.93 ± 0.20 eV, in the RF case ne = (6.8 ± 1.8)×1015 m−3 and kTe = 2.6 ± 0.35 eV. The corresponding gas temperatures are 760±40 K and 440±20 K. (paper)

  11. Lu.sub.1-xI.sub.3:Ce.sub.x--a scintillator for gamma ray spectroscopy and time-of-flight PET

    Science.gov (United States)

    Shah, Kanai S.

    2007-02-06

    The present invention concerns very fast scintillator materials comprising lutetium iodide doped with Cerium (Lu.sub.1-xI.sub.3:Ce.sub.x; LuI.sub.3:Ce). The LuI.sub.3 scintillator material has surprisingly good characteristics including high light output, high gamma ray stopping efficiency, fast response, low cost, good proportionality, and minimal afterglow that the material is useful for gamma ray spectroscopy, medical imaging, nuclear and high energy physics research, diffraction, non-destructive testing, nuclear treaty verification and safeguards, and geological exploration. The timing resolution of the scintillators of the present invention provide compositions capable of resolving the position of an annihilation event within a portion of a human body cross-section.

  12. The efficiency calibration and development of environmental correction factors for an in situ high-resolution gamma spectroscopy well logging system

    International Nuclear Information System (INIS)

    A Gamma Spectroscopy Logging System (GSLS) has been developed to study sub-surface radionuclide contamination. Absolute efficiency calibration of the GSLS was performed using simple cylindrical borehole geometry. The calibration source incorporated naturally occurring radioactive material (NORM) that emitted photons ranging from 186-keV to 2,614-keV. More complex borehole geometries were modeled using commercially available shielding software. A linear relationship was found between increasing source thickness and relative photon fluence rates at the detector. Examination of varying porosity and moisture content showed that as porosity increases, relative photon fluence rates increase linearly for all energies. Attenuation effects due to iron, water, PVC, and concrete cylindrical shields were found to agree with previous studies. Regression analyses produced energy-dependent equations for efficiency corrections applicable to spectral gamma-ray well logs collected under non-standard borehole conditions

  13. Moessbauer spectroscopy study on the effect of infrared and gamma radiation on the structure of minerals. Part of a coordinated programme on development of methods for application of Moessbauer spectroscopy in mineralogy, soil sciences and the study of ceramics

    International Nuclear Information System (INIS)

    A number of fundamental and applied problems were studied by Moessbauer spectroscopy. (a) The observation of Moessbauer spectra in iron silacate deerite with respect to the structure of this mineral was interpreted by charge transfer between iron ions, and correlated with thermally activated electron delocalisation. (b) The studies of local coals showed the suitability of Moessbauer spectroscopy in control of the desulpherisation process. (c) A simple method to use Moessbauer measurement to determine the obstructions in water pipes was developed

  14. Feasibility study of applying gamma-irradiation combined with certain growth regulators on some qualitative characters and yield of onion

    International Nuclear Information System (INIS)

    Two field experiments were carried out during 1982/1983 and 1983/1984 growing seasons at experimental farm, ain shams university , faculty of agriculture at shalakan, to study effect of gamma - irradiation and growth regulators in improving quality and yield of onion. every experiment included eighteen treatments which were the combination of three irradiation doses and three levels of spraying with indoleacetic acid (IAA) or gibberellic acid (GA3) as well as two stages of spraying numbers of growth regulators,, and the treatment were as following: 1) Gamma - ray doses: allium cepa variety behairy seeds were irradiated with gamma -rays at the doses of 0.0, 6.5 and 13.0 K.rad using 60 Co at nuclear research center in the atomic energy authority at inshas. the irradiated seeds sown in the nursery at 1st october and 1st november and the seedlings were transplanted in the field at 14 th january, and 1st febreury, in both first and second growing seasons respectively. 2) growth regulators levels: the onion plants developed from irradiated and unirradiated seeds were sprayed with IAA in the concentrations of 0.0, 25 and 50 ppm and GA3 in the concentrations of 0.0, 100 and 200 ppm using berelex in the form of water soluble tablets

  15. Summary Report on the 2. Research Coordination Meeting on Development of a Reference Database for Particle-Induced Gamma Ray Emission (PIGE) Spectroscopy

    International Nuclear Information System (INIS)

    The Second Research Coordination Meeting (RCM) of the IAEA Coordinated Research Project (CRP) on 'Development of a Reference Database for Particle-Induced Gamma-ray Emission (PIGE) Spectroscopy' was held at the IAEA, Vienna, from 8 - 12 October 2012. A summary of the participants' presentations is given as well as background information and recommendations concerning the methodology for the remaining part of the CRP. The feasibility of performing evaluations and developing computer codes to implement the PIGE database was discussed. A list of pending measurements was produced and the monitoring, compilation and assessment of these data was assigned to participants. (author)

  16. Studies on the rubber phase stability in gamma irradiated polystyrene-SBR blends by using FT-IR and Raman spectroscopy

    International Nuclear Information System (INIS)

    Improvement in the impact properties of polystyrene-SBR blends produced by different concentrations and types of styrene-butadiene rubber (SBR) was studied. The samples were gamma irradiated at different doses to achieve good adhesion, and consequently good stability, between the rubbery phase and the polystyrene matrix, producing an improvement in the impact properties. The results show that the best Izod impact was obtained for a blend with 10% SBR and with a dose of 100 kGy. Several samples with 0%, 3%, 5% and 10% of SBR were prepared and characterized by FT-IR and FT-Raman spectroscopies

  17. Summary report of the first research coordination meeting on development of a reference database for particle-induced gamma ray emission (PIGE) spectroscopy

    International Nuclear Information System (INIS)

    The First Research Coordination Meeting (RCM) of the IAEA Coordinated Research Project (CRP) on 'Development of a Reference Database for Particle-Induced Gamma-ray Emission (PIGE) Spectroscopy' was held at the IAEA, Vienna, from 16-20 May 2011. A summary of the participants' presentations is given as well as background information, objectives and recommendations concerning approach and methodology. The extension of the IBANDL database format to include PIGE data was discussed. The different tasks to achieve the CRP objectives were assigned to participants. A list of priority measurements was produced and the individual sets of measurements assigned to participants. (author)

  18. The SMARTS Multi-epoch Optical Spectroscopy Atlas (SAMOSA): Using Emission Line Variability to Probe the Location of the Blazar Gamma-emitting Region

    CERN Document Server

    Isler, Jedidah C; Bailyn, C; Smith, P S; Coppi, P; Brady, M; Macpherson, E; Hasan, I; Buxton, M

    2015-01-01

    We present multi-epoch optical spectroscopy of seven southern Fermi-monitored blazars from 2008 - 2013 using the Small and Medium Aperture Research Telescope System (SMARTS), with supplemental spectroscopy and polarization data from the Steward Observatory. We find that the emission lines are much less variable than the continuum; 4 of 7 blazars had no detectable emission line variability over the 5 years. This is consistent with photoionization primarily by an accretion disk, allowing us to use the lines as a probe of disk activity. Comparing optical emission line flux with Fermi $\\gamma$-ray flux and optical polarized flux, we investigate whether relativistic jet variability is related to the accretion flow. In general, we see no such dependence, suggesting the jet variability is likely caused by internal processes like turbulence or shock acceleration rather than a variable accretion rate. However, three sources showed statistically significant emission line flares in close temporal proximity to very large...

  19. The use of in situ gamma spectroscopy to study radionuclides contributing to dose rate at 540 MWe pressurised heavy water reactors

    International Nuclear Information System (INIS)

    Tarapur Atomic Power Station Unit-3 and 4 are twin reactors of 540 MWe capacity each. Unit-4 and Unit-3 operated for about 1030 and 910 effective full power days (EFPD) respectively. With the reactor operation, radiation field on reactor system equipments mainly on PHT system, Moderator system and spent fuel transfer system increases due to deposition of fission and activation product. These dose rates significantly contribute to the external exposure and stations collective dose in maintenance activities during reactor outages. In situ gamma spectroscopy has been successfully used at TAPS 3 and 4 operating nuclear facility to identify the radionuclide contributing to the dose rates for incorporating the corrective measures to control these sources and limit the exposures to ALARA. In situ gamma spectroscopy offers advantages over the traditional method of extracting a representative sample, transporting it to a laboratory, and then preparing the sample for counting. Some samples are physically difficult to obtain (material inside pipes, tanks, strainers, filters, very radioactive samples like resin beads, pressurized cover gases, heavy water sample collection). Since in situ spectroscopy is a non-contact process, and since the sample doesn't need to be physically extracted, these problems are minimized. In situ spectroscopy can give near-instantaneous results, and therefore allow prompt decisions to be made while the equipment is in the field. The availability of nuclide-specific information rather than just gross count or dose-rate information can allow better decisions to be made by the plant Health Physicist and plant management to define the optimum amount of personnel protection for the job. Reliable knowledge of exactly what radio nuclides are present, where they are located, will allow the job to be planned better. This better knowledge should lead to a safer operation, lower dose, lower risk of things going wrong, lower cost, and a quicker finish. Today

  20. A modified algorithm for continuous wave near infrared spectroscopy applied to in-vivo animal experiments and on human skin

    Science.gov (United States)

    Klaessens, John H. G. M.; Hopman, Jeroen C. W.; Liem, K. Djien; de Roode, Rowland; Verdaasdonk, Rudolf M.; Thijssen, Johan M.

    2008-02-01

    Continuous wave Near Infrared Spectroscopy is a well known non invasive technique for measuring changes in tissue oxygenation. Absorption changes (ΔO2Hb and ΔHHb) are calculated from the light attenuations using the modified Lambert Beer equation. Generally, the concentration changes are calculated relative to the concentration at a starting point in time (delta time method). It is also possible, under certain assumptions, to calculate the concentrations by subtracting the equations at different wavelengths (delta wavelength method). We derived a new algorithm and will show the possibilities and limitations. In the delta wavelength method, the assumption is that the oxygen independent attenuation term will be eliminated from the formula even if its value changes in time, we verified the results with the classical delta time method using extinction coefficients from different literature sources for the wavelengths 767nm, 850nm and 905nm. The different methods of calculating concentration changes were applied to the data collected from animal experiments. The animals (lambs) were in a stable normoxic condition; stepwise they were made hypoxic and thereafter they returned to normoxic condition. The two algorithms were also applied for measuring two dimensional blood oxygen saturation changes in human skin tissue. The different oxygen saturation levels were induced by alterations in the respiration and by temporary arm clamping. The new delta wavelength method yielded in a steady state measurement the same changes in oxy and deoxy hemoglobin as the classical delta time method. The advantage of the new method is the independence of eventual variation of the oxygen independent attenuations in time.

  1. {gamma}-spectroscopy and radioactive beams: search for highly deformed exotic nuclei; Detection {gamma} et faisceaux radioactifs: recherche de noyaux exotiques tres deformes

    Energy Technology Data Exchange (ETDEWEB)

    Rosse, B

    2006-07-15

    This work is devoted to the search for highly deformed nuclei under extreme conditions of isospin, located near the proton drip-line, around A {approx} 130. The experiment was performed at GANIL (Caen) with the SPIRAL radioactive beam facility. The nuclei of interest were produced by fusion-evaporation reactions induced by the neutron deficient Kr{sup 76} radioactive beam (T1/2 = 14.8 h). {gamma}-rays were detected by the EXOGAM array, composed of 11 segmented germanium clover detectors, for which a new segment calibration method has been developed. To extract fusion-evaporation events of a overwhelming background due to the radioactivity of the beam, the EXOGAM array was coupled with the light charged particle detector DIAMANT and the high acceptance VAMOS spectrometer. The latter was used for the first time to detect fusion-evaporation residues. The detailed data analysis allowed us to demonstrate that the EXOGAM + DIAMANT + VAMOS coupling is operational and essential to investigate the structure of these nuclei. Furthermore, the first {gamma} transition was observed in the very exotic odd-odd Pm{sup 130} nucleus. The results have been interpreted with static and dynamic self-consistent microscopic calculations in collaboration with the Theoretical Physicists of the IPN Lyon. (author)

  2. Study of gamma radiation effect on natural polymer of extracted peat humic/humate to apply in agriculture

    International Nuclear Information System (INIS)

    Study of gamma radiation effects on the natural polymer such as humic/ humate, which was extracted from the peat, has been carried out. The parameters effect on the extraction yield of humic such as alkali concentration and ratio of NaOH and KOH mixture; dilution; extraction temperature and extraction time have been evaluated. The studied results indicated that the optimal parameters of extracting process of humic/humate have been investigated as follows: concentration of alkali is 2% with ratio of NaOH:KOH (1:1); at temperature 65 oC for 2 ninehrs, extraction yield is 76%. Under action of ionizing radiation like gamma Co-60, humic/humate is occurring crosslinking and degradation reactions in which depends on the absorbed dose and irradiation conditions. The optimal dose for degradation of humic in powder form was 500 kGy while in 9% solution that was only 150 kGy. The molecular weight of the original humic was 7,427 Da and after irradiation of 150 kGy that was reduced and reached the value of 5,384 Da, the dissolubility of irradiated humic increases 1.8 times compared with the original. The other characters of product such as functional group exchange (IR spectra), the viscosity of solution of irradiated humic have been investigated as well. The product is promising in good application in future. (author)

  3. High accuracy/high precision determination of 235U in nondestructive assay standards by gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    High precision gamma spectrometry measurements have been made on five sets of five uranium isotope abundance reference materials for nondestructive assay (NDA). These sets are intended for international safeguards use as primary reference materials for the determination of the 235U abundance in homogeneous uranium bulk material by gamma spectrometry. The measurements are to determine the counting rate uniformity of the 235U 185.7 keV gamma as well as the 235U isotope abundance for each sample. Since the samples are packaged such that the U3O8 is infinitely thick for the 185.7 keV gamma, the measured counting rate is not dependent on the material density. In addition, the activity observed by the detector is colimated to simulate calibration conditions used to measure bulk material in the field. The results of this study indicate that accuracy of 235U determination via gamma spectrometry, in the range of few hundredths of a percent (2sigma), is achievable. The main requirement for achieving this level of accuracy is a set of standards whose 235U isotope abundance are known to within 0.01% (2sigma)

  4. a Quantitative Method for Analyzing Radioactive Nuclides in Infinite Composite Materials Using High-Resolution Gamma-Ray Spectroscopy.

    Science.gov (United States)

    Day, John Henry, Jr.

    1982-03-01

    A theory is formulated in which the concentration of a radionuclide uniformly distributed throughout an infinite medium is related to the photopeak count rate of a signature gamma ray acquired by a detector within the medium. The mass fraction of the i('th) radionuclide in the medium is given by f(,i) = W(,i)(psi)(,i) (E)/(lamda)(,i)I(,I)(E)K(E); where (psi)(,i)(E) and I(,i)(E) are the observed photopeak count rate and absolute intensity for a gamma-ray emission of energy E. (lamda)(,i) and W(,i) are the decay constant and isotopic mass, respectively. It is shown that the function K(E) is a source volume integration over(' )(epsilon)(E,R)B(E,R)exp( -(SIGMA)(mu)(E)r(R))/(VBAR)R(VBAR)('2) which depends on gamma-ray energy only. Values of the narrow-beam attenuation coefficient (mu) are known for many materials. However, several laboratory experiments are performed in order to obtain data from which to empirically determine the detector response function (epsilon)(E,R)(' )and the gamma-ray build -up-factor(' )B(E,R). Special experimental instrumentation for analyzing radionuclides in infinite composite materials using high -resolution gamma-ray spectrometry is introduced. A probe is constructed which contains a coaxial high-purity germanium crystal to detect the gamma rays, a cryostat to cool the crystal and electronic circuitry to process the signal from the detector. Laboratory models of natural formations are prepared using high-grade radioactive samples diluted with silicon dioxide to obtain the desired concentrations. Each model is sampled to obtain X-ray fluorescence, delayed neutron and fluorimetric analysis from independent laboratories to compare with results using the method presented in this work.

  5. Monte Carlo simulation of the response functions of CdTe detectors to be applied in x-ray spectroscopy

    International Nuclear Information System (INIS)

    In this work, the energy response functions of a CdTe detector were obtained by Monte Carlo (MC) simulation in the energy range from 5 to 160 keV, using the PENELOPE code. In the response calculations the carrier transport features and the detector resolution were included. The computed energy response function was validated through comparison with experimental results obtained with 241Am and 152Eu sources. In order to investigate the influence of the correction by the detector response at diagnostic energy range, x-ray spectra were measured using a CdTe detector (model XR-100T, Amptek), and then corrected by the energy response of the detector using the stripping procedure. Results showed that the CdTe exhibits good energy response at low energies (below 40 keV), showing only small distortions on the measured spectra. For energies below about 80 keV, the contribution of the escape of Cd- and Te-K x-rays produce significant distortions on the measured x-ray spectra. For higher energies, the most important correction is the detector efficiency and the carrier trapping effects. The results showed that, after correction by the energy response, the measured spectra are in good agreement with those provided by a theoretical model of the literature. Finally, our results showed that the detailed knowledge of the response function and a proper correction procedure are fundamental for achieving more accurate spectra from which quality parameters (i.e., half-value layer and homogeneity coefficient) can be determined. - Highlights: • The response function of a CdTe detector was determined by Monte Carlo simulation. • The simulation takes into account all interaction process, the carrier transport and the Gaussian resolution. • The influence of different effects of spectral distortion was investigated. • CdTe detector was applied for x-ray spectroscopy. • The proper correction procedure is needed to achieve realistic x-ray spectra

  6. Coupled multi-group neutron photon transport for the simulation of high-resolution gamma-ray spectroscopy applications

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Kimberly A. [Georgia Inst. of Technology, Atlanta, GA (United States)

    2009-08-01

    The accurate and efficient simulation of coupled neutron-photon problems is necessary for several important radiation detection applications. Examples include the detection of nuclear threats concealed in cargo containers and prompt gamma neutron activation analysis for nondestructive determination of elemental composition of unknown samples.

  7. On-line gamma spectroscopy system for observation of the cover gas of KNK II, description and instruction

    International Nuclear Information System (INIS)

    To get more information about the further evolution of defected fuel pins in the sodium cooled fast reactor KNK II, an on-line measuring system to observe the cover gas activity was developed. A computerized gamma-spectroscope evaluates on-line some significant photo-peaks. The paper describes the hardware and software and gives an instruction manual for this system

  8. Gamma radiation applied to extend the shelf-life of lamb meat vacuum packed and stored under refrigeration

    International Nuclear Information System (INIS)

    The State of Sao Paulo has experienced in recent years a significant increase in production, supply and consumption of lamb meat. With the current trend of demand for products of greater convenience, with speed and ease preparation, there is the need to invest in the market supply of refrigerated lamb cuts. Accordingly, irradiation with ionizing energy could be a viable alternative for the marketing of refrigerated cuts of lamb meat. The aim of this work was to study the application of different doses of gamma radiation in order to extend the stability of lamb meat vacuum packed and stored under refrigeration. For this, first a preliminary experiment was conducted aiming to determine parameters such as irradiation dose and storage time. The lamb loins (Longissimus dorsi) were vacuum packed, irradiated with doses of 1,0, 3,0 and 5,0 kGy and stored under refrigeration in cooling chamber at 1 °C. According to the results, a dose of 3,0 kGy may be indicated as the maximum dose of irradiation. After establishing these parameters, the final experiment began, and for that, the lamb loin samples were vacuum packaged and irradiated with doses zero (control), 1,5 kGy and 3,0 kGy and stored under refrigeration at 1 °C. In predetermined periods (zero, 14, 28, 42 and 56 days) microbiological and physical chemical analysis were carried out. Also, a sensory acceptance test was conducted, with 63 consumers, which evaluated aroma, texture, juiciness, flavor and overall quality attributes. All data were statistically evaluated using contrasts between means, with a significance level of 5%. The results obtained for microbiological testing of all samples were absence of Salmonella sp. and sporadic counts of coliforms at 45 °C and Staphylococcus aureus (<10 (est) CFU/g). For other microbiological analysis there were significant effects (p <0,05) of treatment, and time. However, for the physicochemical characteristics, there were only differences (p <0,05) of time from zero to 28

  9. Decomposition Of Continuum GAMMA Ray Spectra For Point Sources By Using Gold Algorithm

    International Nuclear Information System (INIS)

    In this work, we try for decomposition of continuum gamma ray spectra using Gold algorithm. The problem is applied for the gamma spectra of Co-60, Cs-137 and Eu-152 point source for HPGe GC2018 gamma spectroscopy. The results show that the convergence speed is faster than results for using MLEM algorithm and the largest difference of the peak area ratios before and after unfolding from P/T values decreases 15%. (author)

  10. Investigation of hyperfine interactions in DNA and antibody of different lineages of mice infected by T. cruzi by perturbed gamma-gamma angular correlation spectroscopy

    International Nuclear Information System (INIS)

    In the present work perturbed angular correlation (PAC) spectroscopy was used to measured electric quadrupole interactions in DNA biomolecules of different mice lineages (A/J, C57BL/6, B6AF1, BXA1 e BXA2), samples of different isotypes of immunoglobulin G (IgG1, IgG2a e IgG2b) and active portions of complete and fragmented immunoglobulin responsible by the immune response. Electric quadrupole interactions were also measured in DNA nitrogenous bases (adenine, cytosine, guanine, thymine). PAC measurements were performed using 111In → 111Cd; 111mCd → 111Cd; 111Ag → 111Cd; e 181Hf → 181Ta as probe nuclei, and carried out at room temperature and liquid nitrogen temperature, in order to investigate dynamic and static hyperfine interactions, respectively. The biomolecule samples were directly marked with the radioactive parent nuclei, whose atom link to a certain site in the biomolecules. The biological materials as well as the probe nuclei were chosen to investigate the possibility to use PAC spectroscopy to measure hyperfine parameters at nuclei from metallic elements bound to biomolecules (including the use of different probe nuclei produced in the decay of parent nuclei of four different metals) and also to study the behavior of different biomolecules by means of the measured hyperfine parameters. Results show differences in the hyperfine interactions of probe nuclei bound to the studied biomolecules. Such differences were observed by variations in the hyperfine parameters, which depend on the type of biomolecule and the results also show that the probe nuclei atom bound to the molecule in some cases and in others do not. (author)

  11. Elemental analysis of water and soil environmental samples in Tabuk area by neutron capture gamma-ray spectroscopy techniques

    International Nuclear Information System (INIS)

    The prompt and delayed gamma-rays due to neutron capture in the nuclei of the constituent elements of three soil samples and one drinking water sample have been measured. The 252Cf and 226Ra/Be isotopic neutron sources are used for neutron irradiation. Also, the hyper pure germanium detection system is used. The soil samples were from Astra, Tadco and El-Gammaz farms, while the water sample was taken from Tabuk city. In case of prompt gamma-ray analysis, a total of 16 elements were identified and the concentration percentage values by weight were calculated for: C, Na, Mg, Al, Si, S, Cl,, Ca, Ti, Cr, Mn, Fe, Co, Zn, Sr ad Pb elements. A comparative study between the results obtained in this work and the results obtained by ICP-MS and EDX-Ray techniques for the same samples is given

  12. A mobile measuring device for the determination of radionuclides in surface waters by in-situ gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    A mobile measuring device to determine radionuclides in surface waters by in-situ gamma-ray spectrometry is presented. Important data (full width at half maximum (FWHM), calibration factors and photopeak efficiency) are reported. The detection limits obtained under realistic conditions demonstrate that this mobile measuring device is appropriate for the detection and evaluation of radionuclides in surface waters in the event of accidents as well as for performing methodical studies using selected radiotracers. (orig.)

  13. Development of a technique for the on line determination of uranium in solution by gamma ray spectroscopy

    International Nuclear Information System (INIS)

    A technique based on gamma ray spectrometry has been developed for the continuous monitoring of uranium in the solution form. Simulated container and support system was designed and fabricated for the development of an efficiency calibration curve and to find the detection limit for the estimation of uranium using 185.7 keV (235U) gamma ray. The system was calibrated for its counting efficiency using HPGe detector system, in a standard source mount to detector geometry. The sensitivity of the detection system and counting time for low-level estimation of uranium has also been established. The detection limit of the monitor is ∼10 mg of uranium per litre of the solution. In order to correct for the density variation of the solution experiment was carried to study the variation of count rate of 185.7 ke V gamma ray of 235U as a function of the density of the solution. This report gives the details of the development of a continuous monitor for the determination of uranium in the solution streams. (author)

  14. 7T Proton Magnetic Resonance Spectroscopy of Gamma-Aminobutyric Acid, Glutamate, and Glutamine Reveals Altered Concentrations in Patients With Schizophrenia and Healthy Siblings

    DEFF Research Database (Denmark)

    Thakkar, Katharine N; Rösler, Lara; Wijnen, Jannie P;

    2016-01-01

    BACKGROUND: The N-methyl-D-aspartate receptor hypofunction model of schizophrenia predicts dysfunction in both glutamatergic and gamma-aminobutyric acidergic (GABAergic) transmission. We addressed this hypothesis by measuring GABA, glutamate, glutamine, and the sum of glutamine plus glutamate...... concentrations in vivo in patients with schizophrenia using proton magnetic resonance spectroscopy at 7T, which allows separation of metabolites that would otherwise overlap at lower field strengths. In addition, we investigated whether altered levels of GABA, glutamate, glutamine, and the sum of glutamine plus......, and 24 healthy nonrelatives. Glutamate, glutamine, and GABA were measured cortically and subcortically in bilateral basal ganglia and occipital cortex. RESULTS: Patients with schizophrenia had reduced cortical GABA compared with healthy relatives and the combined sample of healthy relatives and...

  15. The effects of A single dose of gamma-rays applied on the head on behavior of rats in Morris's water maze and in the open field test

    International Nuclear Information System (INIS)

    The effects of a sublethal dose of gamma-rays applied on the head on selected behavioral parameters were investigated in this study. Adult male Sprague-Dowley rats (n=9) were irradiated with a single dose of 20 Gy of gamma-rays from a 60Co radiation source. The irradiated animals as well as sham-irradiated controls were tested daily in Morris water maze (MWM) (2 sessions per day) and in the open field test. The ability of spatial learning given by latency time to find the hidden platform was followed in MWM. The horizontal and vertical locomotion, the number of crossings of the center of the field and the washing behavior were recorded during an 8-minute test in the open field. The results obtained show, that radiation didn't altered significantly the dynamic of learning in MWM during the experiment. The level of horizontal and vertical locomotory activity in open field was lower in irradiated group in comparison with controls. The number of the crossings of the field's center, related to the level of anxiozity of animals was non-significantly lower in irradiated animals, whereas no differences in number of washing between both groups were detected. The results point to differences in radiosensitivity in various behavioral parameters in rats, maybe due to different level of their control and coordination in CNS. (authors)

  16. Instrumentation for Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    The indigenous efforts in instrumentation for Moessbauer spectroscopy are reviewed. After a brief recapitulation of early developments in this field, the current status is described. Instrumentation for Moessbauer spectroscopy involves various aspects such as, velocity transducer, preparation of the radioactive source in proper host matrix, gamma-ray detectors, electron detectors in the case of conversion electron Moessbauer spectroscopy, data acquisition system, temperature variation facility such as cryostats and furnaces, externally applied magnetic field, etc. While the review attempts to cover most of these aspects, the constituents of a basic modern Moessbauer spectrometer, viz. a constant accelerator Moessbauer drive, a top loading type liquid helium cryostat and an inexpensive microprocessor based data acquisition system are discussed in detail. Developments in personal computer based systems are also indicated. (author). 10 figs., 61 refs

  17. Fully automated radiochemical preparation system for gamma-spectroscopy on fission products and the study of the intruder and vibrational levels in 83Se

    International Nuclear Information System (INIS)

    AUTOBATCH was developed to provide a usable source of short-lived neutron-rich nuclides through chemical preparation of the sample from fission products for detailed gamma-ray spectroscopy, which would complement the output of on-line isotope separators. With AUTOBATCH the gamma rays following the β- decay of 83As were studied to determine the ground state spin and parity of 83As to be 5/2-; the absolute intensity of the β- branch from 83As to 83Se/sup m/ to be 0.3%; the absolute intensity of the ground state β- branch from 83Se/sup m/ to 83Br to be 39%; the halflife of the 5/21+ level to be 3.2 ns; and the structure of 83Se49. Results are used to show that the intruder structure which had been previously observed in the odd mass 49In isotopes could be observed in the N = 49 isotones. The observed structure is discussed in terms of the unified model calculations of Heyde which has been used to describe the intruder structure in the indium nuclei. The intruder structure is most strongly developed, not at core mid-shell, 89Zr49, but rather at core mid-sub-shell 83Se. This difference is qualitatively understood to be due to the blocking of collectivity by the Z = 40 subshell closure which prevents the intruder structure from occurring in 87Sr49 and 89Zr49

  18. Optical-NIR spectroscopy of the puzzling gamma-ray source 3FGL 1603.9-4903/PMN J1603-4904 with X-shooter

    CERN Document Server

    Goldoni, P; Boisson, C; Mueller, C; Dauser, T; Jung, I; Krauss, F; Lenain, J -P; Sol, H

    2015-01-01

    The Fermi/LAT instrument has detected about two thousands Extragalactic High Energy (E > 100 MeV) gamma-ray sources. One of the brightest is 3FGL 1603.9-4903, associated to the radio source PMN J1603-4904. Its nature is not yet clear, it could be either a very peculiar BL Lac or a CSO (Compact Symmetric Object) radio source, considered as the early stage of a radio galaxy. The latter, if confirmed, would be the first detection in gamma-rays for this class of objects. Recently a redshift z=0.18 +/- 0.01 has been claimed on the basis of the detection of a single X-ray line at 5.44 +/- 0.05 keV interpreted as a 6.4 keV (rest frame) fluorescent line. We aim to investigate the nature of 3FGL 1603.9-4903/PMN J1603-4904 using optical to NIR spectroscopy. We observed PMN J1603-4904 with the UV-NIR VLT/X-shooter spectrograph for two hours. We extracted spectra in the VIS and NIR range that we calibrated in flux and corrected for telluric absorption and we systematically searched for absorption and emission features. T...

  19. Measuring the activity of neutron-activation detectors using gamma-spectroscopy technique in the presence of positron decay

    International Nuclear Information System (INIS)

    The present paper is of methodical character and is aimed at drawing experimentators' attention to the systematic error sources occurring on positron-decay nuclide activity measuring with gamma spectrometric method. The paper deals with summing in the detection unit the signals from the measured photons with energy Eph to those from annihilation radiation photons. Summation results in decrease of the area under the total energy absorption peak for measured photons and, as the consequence, in decrease of the sample external radiation measured value

  20. The development of photoemission spectroscopy and its application to the study of semiconductor interfaces Observations on the interplay between basic and applied research (Welch Memorial Lecture)

    Science.gov (United States)

    Spicer, W. E.

    1985-01-01

    A sketch is given of the development of photoemission electron spectroscopy (PES) with emphasis on the author's own experience. Emphasis is placed: (1) on the period between 1958-1970; (2) on the various developments which were required for PES to emerge; and (3) on the strong interactions between applied/fundamental and knowledge/empirically based research. A more detailed discussion is given of the recent (1975-present) application of PES to study the interfaces of III-V semiconductors.

  1. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy and Artificial Neural Networks Applied to Differentiate Escherichia coli papG+/papG- Strains

    OpenAIRE

    Łukasz Lechowicz; Wioletta Adamus-Białek; Wiesław Kaca

    2013-01-01

    Fimbriae are an important pathogenic factor of Escherichia coli during development of urinary tract infections. Here, we describe a new method for identification of Escherichia coli papG+ from papG- strains using the attenuated total reflectance Fourier transform infrared Spectroscopy (ATR FT-IR). We applied artificial neural networks to the analysis of the ATR FT-IR results. These methods allowed to discriminate E. coli papG+ from papG- strains with accuracy of 99%.

  2. Optical simulations for the S3 project - Super separator spectrometer - gamma-electron coincidence spectroscopy of a transfermium nucleus: the 251Md101

    International Nuclear Information System (INIS)

    In analogy with the atomic closed shells giving rise to the stability and high ionisation energies of noble gases, nuclear physics also has its magic numbers of protons and neutrons which enhance nuclear structure stability. Knowledge of the structure of doubly-magic nuclei, both proton and neutron numbers, is crucial to parameterize theoretical models. The discovery of the next and ultimate magic numbers will provide a strong constraint on the many predictions. These two numbers are like the centre coordinates of an area of enhanced stability of the nuclear chart, well known as 'island of stability'. These superheavy nuclei only exist due to pure quantum shell effects. My thesis work deals with two distinct, but complementary, aspects of fundamental physics with the common goal of studying these extreme mass nuclei structure. The first part corresponds to the development of a next generation instrument for nuclear physics to allow synthesis and spectroscopy studies of superheavy nuclei: the Super Separator Spectrometer S3. This project will be installed at SPIRAL2 (GANIL) and has been approved by the French Research National Agency (ANR) within the EQUIPEX framework. It has been designed to take advantage of the high intensity heavy ion beam from the LINAC, giving access to a wide range of physical programs. The second part corresponds to the preparation, realisation and analysis of an experiment on 251-Mendelevium in which the very first prompt gamma-electron coincidence spectroscopy was performed for a transfermium nuclei. (author)

  3. Beta dose rates derived from gamma spectroscopy and low beta anticoincident system of various environmental materials, mainly of archaeological origin

    International Nuclear Information System (INIS)

    Beta dose-rates (BDR) have been derived from tephras, pumices and pottery of archaeological origin. The BDRs were obtained from two counting systems: (1) gamma spectrometry through appropriate conversion of gamma activity to U, Th, 40K concentration values, and (2) by counting total beta, using a gas-flow sample detector in an anticoincidence mode of counting. Assuming radioactive equilibrium in the U and Th series, the two methods of obtaining BDRs are compared. The degree of disequilibrium, the calibration, and radon escape are critically considered. The employment of either method to swift BDR measurements for the TL dating is discussed. The radioactivity measurements of tephras were used also to provenance those, as Santorini volcano might had not been the only eruption in the Aegean in the 2nd mill. B.C., it might have experienced more than one eruptive phase. BDRs in the samples ranged from 13 to about 470 mrads/year and the agreement between the two methods were in general satisfactory. 12 refs.; 2 figs.; 2 tabs

  4. First-year Results of Broadband Spectroscopy of the Brightest Fermi-GBM Gamma-Ray Bursts

    CERN Document Server

    Bissaldi, Elisabetta; Kouveliotou, Chryssa; Briggs, Michael S; Connaughton, Valerie; Greiner, Jochen; Gruber, David; Lichti, Giselher; Bhat, P N; Burgess, J Michael; Chaplin, Vandiver; Diehl, Roland; Fishman, Gerald J; Fitzpatrick, Gerard; Foley, Suzanne; Gibby, Melissa; Giles, Misty; Goldstein, Adam; Guiriec, Sylvain; van der Horst, Alexander J; Kippen, Marc; Lin, Lin; McBreen, Sheila; Meegan, Charles A; Paciesas, William S; Preece, Robert D; Rau, Arne; Tierney, Dave; Wilson-Hodge, Colleen

    2011-01-01

    We present here our results of the temporal and spectral analysis of a sample of 52 bright and hard gamma-ray bursts (GRBs) observed with the Fermi Gamma-ray Burst Monitor (GBM) during its first year of operation (July 2008-July 2009). Our sample was selected from a total of 253 GBM GRBs based on each event peak count rate measured between 0.2 and 40MeV. The final sample comprised 34 long and 18 short GRBs. These numbers show that the GBM sample contains a much larger fraction of short GRBs, than the CGRO/BATSE data set, which we explain as the result of our (different) selection criteria and the improved GBM trigger algorithms, which favor collection of short, bright GRBs over BATSE. A first by-product of our selection methodology is the determination of a detection threshold from the GBM data alone, above which GRBs most likely will be detected in the MeV/GeV range with the Large Area Telescope (LAT) onboard Fermi. This predictor will be very useful for future multiwavelength GRB follow ups with ground and ...

  5. A study of reversible gamma-induced structural transformations in vitreous Ge23.5Sb11.8S64.7 by high-resolution X-ray photoelectron spectroscopy.

    Science.gov (United States)

    Kovalskiy, Andriy; Jain, Himanshu; Miller, Alfred C; Golovchak, Roman Ya; Shpotyuk, Oleh I

    2006-11-16

    The structural origin of reversible gamma-induced effects in vitreous Ge(23.5)Sb(11.8)S(64.7) has been investigated by high-resolution X-ray photoelectron spectroscopy (XPS). The changes in valence band spectrum from gamma-irradiation suggest a decrease of sulfur lone pair electron concentration accompanied by changes in bonding states of S and Ge. The appearance of additional doublets in the core-level XPS spectra of Ge, Sb, and S atoms for gamma-irradiated sample is described by the formation of over- and under-coordinated charged defect pairs (Ge(3)(-)-S(3)(+)) as a result of radiation treatment. The results verify the switching of Ge-S covalent bonds into S-S bonds as the main microstructural mechanism for gamma-induced optical effects in this glass. PMID:17092046

  6. Separation of vinca alkaloid enantiomers by capillary electrophoresis applying cyclodextrin derivatives and characterization of cyclodextrin complexes by nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Sohajda, Tamás; Varga, Erzsébet; Iványi, Róbert; Fejos, Ida; Szente, Lajos; Noszál, Béla; Béni, Szabolcs

    2010-12-15

    In this work, the enantiomeric separation of three vinca alkaloid enantiomers (vincamine, vinpocetine and vincadifformine) has been investigated in an aqueous capillary electrophoresis (CE) system using cyclodextrins (CDs). The investigated CDs were the native alpha-, beta-, and gamma-CDs and their hydroxypropylated, randomly methylated, carboxymethylated and sulfobutylated derivatives. The first part of this study consisted of the determination of the apparent averaged complex stability constants with the selected CDs. Several parameters, such as the nature and the concentration of the CD, were studied and were found to have a significant effect on the enantiomeric resolution for all studied compounds. All three vinca alkaloids were successfully enantioseparated with CDs where different migration orders were observed in case of several CDs depending on the cavity size or substituent of the host. Chiral separation and determination of the stability constants were also performed with NMR spectroscopy which confirmed the CE results. Averaged stoichiometries of the complexes were determined using the Job plot method resulting in a 1:1 complex irrespective of the alkaloid enantiomers or cyclodextrin derivative. The structures of the inclusion complexes were elucidated using 2D ROESY NMR spectroscopy. On the basis of NMR results reversal of enantiomer migration order was clarified in various cases. PMID:20724093

  7. Nuclear spectroscopy

    CERN Document Server

    Ajzenberg-Selove, Fay

    1960-01-01

    Nuclear Spectroscopy, Part A deals with the experimental and theoretical techniques involved in nuclear spectroscopy.This book discusses the interactions of charged particles with matter, gaseous ionization detectors, and particular mass attenuation coefficients. The magnetic gamma-ray spectrometers for photo or internal-conversion electrons, general characteristics of cross-section variation with energy, and measurement of fast neutron spectra are also elaborated. This text likewise covers the elastic scattering of photons by nuclei and measurement of widths of gamma-radiating levels.This pub

  8. Luminescence spectroscopy applied to a study of the curing process of diglycidyl-ether of bisphenol-A (DGEBA)

    OpenAIRE

    Rita de Cássia Mendonça Sales; Deborah Dibbern Brunelli

    2005-01-01

    This work involved the application of luminescence spectroscopy under steady-state conditions to study the curing process of the epoxy resin diglycidyl-ether of bisphenol-A (DGEBA) using the curing agents 4,4'-diaminodiphenylmethane (DDM) and 4,4'-diaminodiphenylsulfone (DDS). Two fluorescence methods were employed: the intrinsic method related to the polymeric matrix and the extrinsic method, using the molecular probe 9-anthroic acid (9-AA). Stoichiometric mixtures, with and without 9-AA, we...

  9. Luminescence spectroscopy and microscopy applied to study gem materials: a case study of C centre containing diamonds

    Science.gov (United States)

    Hainschwang, Thomas; Karampelas, Stefanos; Fritsch, Emmanuel; Notari, Franck

    2013-06-01

    The methods of luminescence spectroscopy and microscopy are widely used for the analysis of gem materials. This paper gives an overview of the most important applications of the analysis of laser and UV excited luminescence by spectroscopy and visually by microscopy with emphasis on diamond, and specifically natural type Ib diamond, little studied so far. Luminescence based techniques are paramount to the gemmological analysis of diamond, in order to determine whether it is natural, treated or synthetic. The great sensitivity of luminescence helps detect some emitting centres that are undetectable by any other analytical method. Hence, especially for diamond, luminescence is an enabling technology, as illustrated by its pioneering use of imagery for the separation of natural and synthetic diamond, and of spectroscopy for the detection of High Pressure-High Temperature treatment. For all other gemstones the applications are at the moment less numerous, but nevertheless they remain highly important. They provide quickly information on the identification of a gem material, and its treatment. Besides the study of broad band emissions caused by various colour centres, the typical PL-causing trace elements (amongst others) are chromium, manganese, uranium and rare earth elements. In pearls the study of broad band luminescence can be useful, and particularly the study of pink to red porphyrin luminescence in pearls from certain species such as Pinctada and Pteria and others can help identify the pearl-producing mollusc, or if a pearl has been dyed or not. Type Ib diamonds are representative of the importance and complexity of the analysis of luminescence by microscopy and spectroscopy. They show a wide range of sometimes very complex emissions that result in luminescence colours from green to yellow to orange or red. These emissions show generally very inhomogeneous distribution. They are caused by a range of defects, however only a few of them are well characterized.

  10. Structural investigation on gamma-irradiated polyacrylamide hydrogels using small-angle neutron scattering and ultraviolet–visible spectroscopy

    Indian Academy of Sciences (India)

    Sivananatham M; Tata B V R; Aswal V K

    2016-03-01

    Small-angle neutron scattering (SANS) and ultraviolet (UV)–visible spectroscopictechniques are used to investigate the microstructural changes in polyacrylamide (PAAm) hydrogels on gamma irradiation. SANS measurements have revealed the presence of inhomogeneities in nanometre scale and reduction of their size with increase in dose. Analysis of SANS data alsorevealed the increase in the correlation length with increase in dose. The extinction coefficient obtained from the UV–visible spectroscopic studies exhibited $\\lambda^{−\\beta}$ dependence between 500 and 700 nm and is understood to arise from the existence of scatterers (inhomogeneities) in submicron scale in PAAm hydrogels. The increase in value of exponent $\\beta$ with increase in dose indicates that the size of scatterers decrease with increase in dose.

  11. OSIRIS—Gamma-ray spectroscopy software for on-site inspections under the Comprehensive Nuclear-Test-Ban Treaty

    International Nuclear Information System (INIS)

    We have designed and tested software for the acquisition and analysis of high-resolution gamma-ray spectra during on-site inspections under the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The On-Site Inspection RadioIsotopic Spectroscopy—OSIRIS—software filters the spectral data to display only radioisotopic information relevant to CTBT on-site inspections, e.g.,131I. A set of over 100 fission-product spectra was employed for OSIRIS testing. These spectra were measured where possible, or generated by modeling. The test spectral compositions include non-nuclear-explosion scenarios, e.g., a severe nuclear reactor accident, and nuclear-explosion scenarios such as a vented underground nuclear test. Comparing its computer-based analyses to expert visual analyses of the test spectra, OSIRIS correctly identifies CTBT-relevant fission product isotopes at the 95% level or better

  12. OSIRIS—Gamma-ray spectroscopy software for on-site inspections under the Comprehensive Nuclear-Test-Ban Treaty

    Energy Technology Data Exchange (ETDEWEB)

    Caffrey, A.J., E-mail: Gus.Caffrey@inl.gov [Idaho National Laboratory, Idaho Falls, ID (United States); Bowyer, T.W. [Pacific Northwest National Laboratory, Richland, WA (United States); Egger, A.E. [Idaho National Laboratory, Idaho Falls, ID (United States); Hall, J.C. [Pacific Northwest National Laboratory, Richland, WA (United States); Kelly, S.M.; Krebs, K.M. [Idaho National Laboratory, Idaho Falls, ID (United States); Kreek, S.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Jordan, D.V.; Milbrath, B.D. [Pacific Northwest National Laboratory, Richland, WA (United States); Padgett, S.W. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Wharton, C.J. [Idaho National Laboratory, Idaho Falls, ID (United States); Wimer, N.G. [Lawrence Livermore National Laboratory, Livermore, CA (United States)

    2015-06-01

    We have designed and tested software for the acquisition and analysis of high-resolution gamma-ray spectra during on-site inspections under the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The On-Site Inspection RadioIsotopic Spectroscopy—OSIRIS—software filters the spectral data to display only radioisotopic information relevant to CTBT on-site inspections, e.g.,{sup 131}I. A set of over 100 fission-product spectra was employed for OSIRIS testing. These spectra were measured where possible, or generated by modeling. The test spectral compositions include non-nuclear-explosion scenarios, e.g., a severe nuclear reactor accident, and nuclear-explosion scenarios such as a vented underground nuclear test. Comparing its computer-based analyses to expert visual analyses of the test spectra, OSIRIS correctly identifies CTBT-relevant fission product isotopes at the 95% level or better.

  13. Observation of Spin-Dependent Charge Symmetry Breaking in $\\Lambda N$ Interaction: Gamma-Ray Spectroscopy of $^4_{\\Lambda }$He

    CERN Document Server

    Yamamoto, T O; Akazawa, Y; Amano, N; Aoki, K; Botta, E; Chiga, N; Ekawa, H; Evtoukhovitch, P; Feliciello, A; Fujita, M; Gogami, T; Hasegawa, S; Hayakawa, S H; Hayakawa, T; Honda, R; Hosomi, K; Hwang, S H; Ichige, N; Ichikawa, Y; Ikeda, M; Imai, K; Ishimoto, S; Kanatsuki, S; Kim, M H; Kim, S H; Kinbara, S; Koike, T; Lee, J Y; Marcello, S; Miwa, K; Moon, T; Nagae, T; Nagao, S; Nakada, Y; Nakagawa, M; Ogura, Y; Sakaguchi, A; Sako, H; Sasaki, Y; Sato, S; Shiozaki, T; Shirotori, K; Sugimura, H; Suto, S; Suzuki, S; Takahashi, T; Tamura, H; Tanabe, K; Tanida, K; Tsamalaidze, Z; Ukai, M; Yamamoto, Y; Yang, S B

    2015-01-01

    The energy spacing between the ground-state spin doublet of $^4_\\Lambda $He(1$^+$,0$^+$) was determined to be $1406 \\pm 2 \\pm 2$ keV, by measuring $\\gamma$ rays for the $1^+ \\to 0^+$ transition with a high efficiency germanium detector array in coincidence with the $^4$He$(K^-,\\pi^-)$ $^4_\\Lambda $He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus $^4_\\Lambda $H, the present result clearly indicates the existence of charge symmetry breaking (CSB) in $\\Lambda N$ interaction. It is also found that the CSB effect is large in the $0^+$ ground state but is by one order of magnitude smaller in the $1^+$ excited state, demonstrating that the $\\Lambda N$ CSB interaction has spin dependence.

  14. FIRST-YEAR RESULTS OF BROADBAND SPECTROSCOPY OF THE BRIGHTEST FERMI-GBM GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    We present our results of the temporal and spectral analysis of a sample of 52 bright and hard gamma-ray bursts (GRBs) observed with the Fermi Gamma-ray Burst Monitor (GBM) during its first year of operation (2008 July-2009 July).Our sample was selected from a total of 253 GBM GRBs based on the event peak count rate measured between 0.2 and 40 MeV. The final sample comprised of 34 long and 18 short GRBs. These numbers show that the GBM sample contains a much larger fraction of short GRBs than the CGRO/BATSE data set, which we explain as the result of our (different) selection criteria, which favor collection of short, bright GRBs over BATSE. A first by-product of our selection methodology is the determination of a detection threshold from the GBM data alone, above which GRBs most likely will be detected in the MeV/GeV range with the Large Area Telescope on board Fermi. This predictor will be very useful for future multi-wavelength GRB follow-ups with ground- and space-based observatories. Further, we have estimated the burst durations up to 10 MeV and for the first time expanded the duration-energy relationship in the GRB light curves to high energies. We confirm that GRB durations decline with energy as a power law with index approximately -0.4, as was found earlier with the BATSE data and we also notice evidence of a possible cutoff or break at higher energies. Finally, we performed time-integrated spectral analysis of all 52 bursts and compared their spectral parameters with those obtained with the larger data sample of the BATSE data. We find that the two parameter data sets are similar and confirm that short GRBs are in general harder than longer ones.

  15. Measurement of (n,xn) reaction cross-sections using prompt {gamma} spectroscopy at neutron beams with high instantaneous flux; Mesure de sections efficaces de reaction (n,xn) par spectroscopie {gamma} prompte aupres d'un faisceau a tres haut flux instantane

    Energy Technology Data Exchange (ETDEWEB)

    Lukic, S

    2004-10-15

    The work presented in this thesis is situated in the context of the GEDEON program of neutron cross-section measurements. This program is motivated by the perspectives recently opened by projects of nuclear waste treatment and energy production. There is an obvious lack of experimental data on (n,xn) reactions in the databases, especially in the case of very radioactive isotopes. An important technique to measure cross-sections of these reactions is the prompt {gamma}-ray spectroscopy at white pulsed neutron beams with very high instantaneous flux. In this work, inelastic scattering and (n,xn) reactions cross-section measurements were performed on a lead sample from threshold to 20 MeV by prompt {gamma}-ray spectroscopy at the white neutron beam generated by GELINA facility in Geel, Belgium. Digital methods were developed to treat HPGe CLOVER detector signals and separate {gamma}-rays induced by the fastest neutrons from those belonging to the flash. Partial cross-sections for the production of several transitions in natural lead were measured and analyzed using theoretical calculations in order to separate the contributions of different reactions leading to the same residual isotope. Total cross-sections of the reactions in question were estimated. The results were compared to the TALYSS code theoretical calculations, as well as to other experimental results. This experiment has served to validate the method and it opens the way to measure (n,xn) reactions cross-sections with high instantaneous neutron flux on actinides, particularly the U{sup 233}(n,2n) reaction which is important for the thorium cycle. (author)

  16. Fourier transformation methods in the field of gamma spectrometry

    Indian Academy of Sciences (India)

    A Abdel-Hafiez

    2006-09-01

    The basic principles of a new version of Fourier transformation is presented. This new version was applied to solve some main problems such as smoothing, and denoising in gamma spectroscopy. The mathematical procedures were first tested by simulated data and then by actual experimental data.

  17. Application of time-series analysis to induced gamma ray spectroscopy logs from two Cold Lake heavy-oil observation wells

    International Nuclear Information System (INIS)

    This paper reports on induced gamma ray spectroscopy (IGRS) logs from two cyclic-steam-stimulation observation wells in Cold Lake that were analyzed to determine the vertical resolution and repeatability of data derived from gamma rays of inelastic and capture neutron reactions. Time-series analysis, a technique that uses the Fourier representation of the log data, was used to quantify the vertical resolution and the signal/noise characteristics of various IGRS log curves and to compute the coherence vs. spatial frequency of data collected on multiple IGRS passes. The coherence function ranges from 1.0 for perfect repeatability to 0.0 for incoherent noise. Because no real variations in the measured data were expected for the 12- to 24-hour data-collection period, andy deviation of the coherence function from 1.0 is attributed to incoherent noise. Generally, coherence is high at low frequencies (large vertical scales) and low at high frequencies (small vertical scales). By noting the frequency at which the coherence level decreases to the expected value of random noise, we can quantify the vertical resolution of a log curve. Data analysis from these wells indicates that both the vertical resolution and repeatability of individual capture and inelastic curves differ. We found that the H-yield and capture curves have the highest vertical resolution (∼0.3m) and the best signal/noise ratios (FSN ∼ 30:1). In contrast, the capture Ca and Si yields are of significantly lower quality (FSN ∼2:1). Only a small difference exist between the vertical resolution of the inelastic C (1.0 m) and O (1.3 m) yields, but the FSN of the O yield is only one-half that of the C yield. Fortunately, the vertical resolution and the repeatability of the C/O ratio, FCO, are determined primarily by the quality of the inelastic C data

  18. Calibration of a telescope for gamma spectroscopy using a new configuration of two Ge(Li) diodes

    International Nuclear Information System (INIS)

    It was developed a telescope to measure gamma-rays in the energy interval 10-1500 KeV, using two Ge(Li) diodes of 40 cm3 each, coaxially mounted in the same cryostat and an anticoincidence Nal(Tl) shielding system. This new configuration allows a much better signal to noise ratio due to the lower diode operating in anticoincidence with the upper one; besides that, one has a high energy resolution (ΔE 241, Na22 and Eu152 are described. From the analysis of the data obtained in the sum coincidence mode, a minimum detectable flux at 511 KeV is estimated to be -3 fotons cm-2 s-1, with a statistical significance of 3σ for 10 hours of observing time at 3 mb of residual atmosphere. This is about the minimum line flux emitted by the Galactic Center. The measurement of the flux at this line would confirm the time variability observed by Riegler and collaborators using data obtained through HEAO-3 satellite. (Author)

  19. Pu300: A Tool for Measurement of Plutonium Age for Arms Control Transparency via Gamma-Ray Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Archer, D E; Luke, S J; Parker, W

    2000-04-19

    Pu300 has particular application in the Arms Control Transparency arena, where very sensitive material is often the subject of tests and measurements. In Arms Control Transparency projects, we attempt to measure attributes of material removed from a nuclear weapon without revealing sensitive information about the material. The measured attribute can either be reported directly or compared against a threshold value. The set of attributes that are measured can be used as a fingerprint for the material. One such attribute for plutonium is material age. Age, in this sense, is defined as the amount of time that has passed since americium separation. The Pu300 system consists of a coaxial HPGe detector and a Canberra Inspector multichannel analyzer. The Inspector allows the high resolution spectral information to be limited by adjusting upper and lower level discriminators so only the information between 330keV and 350keV is collected. The fits of the peaks in the gamma-ray spectrum are fed into a physics code to give an age of the material measured. The physics code is based on the buildup of {sup 241}Am from the decay of {sup 241}Pu.

  20. A digital Compton suppression spectroscopy without gamma-ray coincidence-summing loss using list-mode multispectral data acquisition

    International Nuclear Information System (INIS)

    The study demonstrates the advantages of an innovative list-mode multispectral data acquisition system that allows simultaneous creation of several different single, summed, coincident and anticoincident spectra with a single measurement. One of the consequences of list-mode data file offline processing is a reconstructed spectrum with Compton continuum suppression and without any full-energy peak efficiency deduction owing to true coincidence summing. The spectrometer is designed to read out analogue signal from preamplifier of gamma-ray detectors and to digitalize it using DGF/Pixie-4 software and card package (XIA LLC). This is realized by converting an Ortec Compton suppression data acquisition system into an all-digital spectrometer. Instead of using its timing electronic chain to determine the coincidence event, the analog signals from primary and guard detectors were connected directly into the Pixie-4 card for pulse height and time coincident measurement by individually logging and time stamping each electronic pulse. The data acquired in list-mode included coincidence and anticoincidence events consisting of records of energy and timestamp from primary and guard detectors. Every event was stored in a text file for offline processing and spectral reconstruction. A sophisticated computer simulation was also created with the goals of obtaining a better understanding of the experimental results and calculating efficiency. (author)

  1. Measurement of cross-sections of yttrium (n,xn) threshold reactions by means of gamma spectroscopy

    CERN Document Server

    Chudoba, Petr; Wagner, V; Vrzalova, J; Svoboda, O; Majerle, M; Stefanik, M; Suchopar, M; Kugler, A; Bielewicz, M; Strugalska-Gola, E; Szuta, M; Hervas, D; Herman, T; Geier, B

    2014-01-01

    Neutron activation and gamma spectrometry are usable also f or the determination of cross-sections of different neutron reactions. We have studied the cross-sections of yttrium (n, x n) threshold reactions using quasi-monoenergetic neutron source based on the reaction on 7 Li target at Nuclear Physics Institute of ASCR in Rez. Yttrium (n, x n) threshold reactions are suitable candidates for fast neutron field measurement by activation detectors. Fast neutron field monitoring is necessary already today at a wide range of accelerator facilities and will gain on importance in future fast reactors of generation IV, accelerator transmutation systems or fusion reactors. The knowledge of the cross-sections is crucial for such purpose. Unfortunately, the cross-section is sufficiently known only for 89 Y(n,2n) 88 Y reaction. For higher orders of reactions there are almost no experimental data. Special attention was paid to t he 89 Y(n,3n) 87 Y reaction. The cross-sections of both 89 Y(n,2n) 88 Y and 89 Y(n,3n) 87 Y re...

  2. Feasibility study of performing high precision gamma spectroscopy of ΛΛ hypernuclei in the anti PANDA experiment

    International Nuclear Information System (INIS)

    Hypernuclear research will be one of the main topics addressed by the anti PANDA experiment at the planned Facility for Antiproton and Ion Research anti FAIR. Thanks to the use of stored anti p beams, copious production of double Λ hypernuclei is expected at the anti PANDA experiment, which will enable high precision γ spectroscopy of such nuclei for the first time. At anti PANDA excited states of Ξ- hypernuclei will be used as a basis for the formation of double Λ hypernuclei. For their detection, a devoted hypernuclear detector setup is planned. This setup consists of a primary nuclear target for the production of Ξ-+ anti Ξ pairs, a secondary active target for the hypernuclei formation and the identification of associated decay products and a germanium array detector to perform γ spectroscopy. In the present work, the feasibility of performing high precision γ spectroscopy of double Λ hypernuclei at the anti PANDA experiment has been studied by means of a Monte Carlo simulation. For this issue, the designing and simulation of the devoted detector setup as well as of the mechanism to produce double Λ hypernuclei have been optimized together with the performance of the whole system. In addition, the production yields of double hypernuclei in excitedparticle stable states have been evaluated within a statistical decay model. A strategy for the unique assignment of various newly observed γ-transitions to specific double hypernuclei has been successfully implemented by combining the predicted energy spectra of each target with the measurement of two pion momenta from the subsequent weak decays of a double hypernucleus. Indeed, based on these Monte Carlo simulation, the analysis of the statistical decay of 13ΛΛB has been performed. As result, three γ-transitions associated to the double hypernuclei 11ΛΛBe and to the single hyperfragments 4ΛH and 9ΛBe, have been well identified. For the background handling a method based on time measurement has also

  3. Study of neutron-rich nuclei structure around the N=28 shell closure using the in-beam gamma spectroscopy technique

    International Nuclear Information System (INIS)

    For a few years now, a loss of magicity in neutron-rich nuclei near the neutron drip-line at N=28 has been suggested and observed. Deformation in these nuclei has been observed. The deformation was explained in S isotopes as being due to a moderate reduction of the N=28 shell closure together with a proton induced collectivity originating from the near degeneracy of the proton d3/2 and s1/2 orbitals. As a consequence, the observed deformation seems to result from a subtle interplay between neutron and proton excitations. Since the proton configuration in the Si isotopes is expected to be more stable due to the Z=14 sub-shell gap, 42Si was considered as a key nucleus in order to distinguish the different effects responsible for the structural changes observed at N=28. Even if it is at the limits of our technical possibilities, an in-beam gamma-spectroscopy experiment using two-step fragmentation and one or several nucleons knockout reaction mechanisms was performed at GANIL. The measurement of the energy of the first excited state in 42Si, combined with the observation of 38,40Si and the spectroscopy of 41,43P, has given evidence for the loss of magicity at N=28 far from stability. Modifications of the effective interaction used in modern shell model calculations have been completed following this investigation, increasing its predictive character. This study confirms the role of the tensor force and the density dependence of the spin-orbit interaction in the collapse of the N=28 shell closure. (author)

  4. In-beam {gamma}-ray spectroscopy of two-step fragmentation reactions at relativistic energies. The case of {sup 36}Ca

    Energy Technology Data Exchange (ETDEWEB)

    Doornenbal, P.

    2007-10-23

    A two-step fragmentation experiment has been performed at GSI with the RISING setup. It combines the fragment separator FRS, which allows for the production of radioactive heavy ions at relativistic energies, with a high resolution {gamma}-spectrometer. This combination offers unique possibilities for nuclear structure investigations like the test of shell model predictions far from stability. Within the present work the question if the N=14(16) shell stabilisation in Z=8 oxygen isotopes and the N=20 shell quenching in {sup 32}Mg are symmetric with respect to the isospin projection quantum number Tz has been addressed. New {gamma}-ray decays were found in the neutron deficient {sup 36}Ca and {sup 36}K by impinging a radioactive ion beam of {sup 37}Ca on a secondary {sup 9}Be target. The fragmentation products were selected with the calorimeter telescope CATE and the emitted {gamma}-rays were measured with Ge Cluster, MINIBALL, and BaF{sub 2} HECTOR detectors. For {sup 36}Ca the 2{sub 1}{sup +}{yields}0{sub g.s.}{sup +} transition energy was determined to be 3015(16) keV, which is the heaviest T=2 nucleus from which {gamma}-spectroscopic information has been obtained so far. A comparison between the experimental 2{sub 1}{sup +} energies of {sup 36}Ca and its mirror nucleus {sup 36}S yielded a mirror energy difference of {delta}E{sub M}=-276(16) keV. In order to understand the large {delta}E{sub M} value, the experimental single-particle energies from the A=17, T=1/2 mirror nuclei were taken and applied onto modified isospin symmetric USD interactions in shell model calculations. These calculations were in agreement with the experimental result and showed that the experimental single-particle energies may account empirically for the one body part of Thomas-Ehrman and/or Coulomb effects. A method to extract the lifetime of excited states in fragmentation reactions was investigated. Therefore, the dependence between the lifetime of an excited state and the average de

  5. Luminescence spectroscopy applied to a study of the curing process of diglycidyl-ether of bisphenol-A (DGEBA

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Mendonça Sales

    2005-09-01

    Full Text Available This work involved the application of luminescence spectroscopy under steady-state conditions to study the curing process of the epoxy resin diglycidyl-ether of bisphenol-A (DGEBA using the curing agents 4,4'-diaminodiphenylmethane (DDM and 4,4'-diaminodiphenylsulfone (DDS. Two fluorescence methods were employed: the intrinsic method related to the polymeric matrix and the extrinsic method, using the molecular probe 9-anthroic acid (9-AA. Stoichiometric mixtures, with and without 9-AA, were heated to 120 °C at a 5 °C/min heating rate. These samples were then cured at 120 °C for a further 2 hours and allowed to cool to room temperature for 20 minutes. The results obtained by the two methods indicate that the cross-linking reaction can be monitored by analyzing the spectral changes of the emission bands of DGEBA, curing agents and 9-AA.

  6. Monte Carlo simulation algorithm for pileup effect of pulses in gamma spectroscopy and pileup distortion calculation on 137Cs pulse height spectrum in NaI(Tl detector

    Directory of Open Access Journals (Sweden)

    AA Mowlavi

    2011-12-01

    Full Text Available  In this paper, an algorithm base on Monte Carlo simulation for pileup effect in gamma spectrum of a detection system is presented whose its code was written in FORTRAN language. The code can be run in paralayzable and nonparalazable mode to obtain the pileup distortion and value of pulses pileup for any detection system. The result show, that the computed spectrum of 137Cs is in good agreement with the experimental spectrum in NaI(Tl detector. The free of pileup free spectrum and sub-spectra with different degrees of pulses of pileup are calculated. Also, we can apply it to different sources and detectors for pileup correction.

  7. $\\gamma$ -spectroscopy of n-rich $^{95,96}$Rb nuclei by the incomplete fusion reaction of $^{94}$Kr on $^{7}$Li

    CERN Multimedia

    We propose an experiment with MINIBALL coupled to T-REX to investigate n-rich $^{95,96}$Rb nuclei by the incomplete fusion reaction of $^{94}$Kr on $^{7}$Li. The nuclei of interest will be populated by transfer of a triton into $^{94}$Kr, forming the excited $^{97}$Rb nucleus, followed by the emission of an alpha particle, which will be detected in the Si telescopes of T-REX. The $^{97}$Rb product will evaporate 1 or 2 (with the highest probability) neutrons leading to $^{96}$Rb or $^{95}$Rb, respectively. The aim of the experiment is twofold: \\\\ i) to perform a $\\gamma$- spectroscopy study of $^{95,96}$Rb nuclei with N=58,59, the structure of which is of particular interest in investigating the transition towards stable deformation at N=60, \\\\ ii) to acquire experience in using incomplete fusion reactions with the weakly bound $^{7}$Li target, in order to perform, at a later stage with HIE-ISOLDE, similar measurements induced by n-rich radioactive beams of Sn and Hg, for which at least 5 MeV/nucleon are need...

  8. Characterization and Identification of Gamma-Irradiated Kimchi Cabbage and Broccoli by Electron Spin Resonance Spectroscopy using Different Sample Pre-treatments

    International Nuclear Information System (INIS)

    Electron spin resonance (ESR) spectroscopy of gamma-irradiated fresh broccoli and kimchi cabbage was conducted to identify their irradiation history. Different pretreatments, such as freeze-drying (FD), oven-drying (OD), alcoholic-drying (ALD), and water-washing and alcoholic-drying (WAD) were used to lower the moisture contents of the samples prior to ESR analysis. The non-irradiated samples exhibited a single central signal (g0 = 2.0007) with clear effect of Mn2+, especially in kimchi cabbage. Upon irradiation, there was an increase in the intensity of the central signal, and two side peaks, mutually spaced at 6 mT, were also observed. These side peaks with g1 (left) = 2.023 and g2 (right) = 1.985 were attributed to radiation-induced cellulose radicals. Leaf and stem in broccoli, and root and stem in kimchi cabbage provided good ESR signal responses upon irradiation. The signal noise was reduced in case of ALD and WAD pretreatments, particularly due to Mn2+ signals. The ALD treatment was found most feasible to detect the improved ESR spectra in the irradiated samples. (author)

  9. Optimum method to determine radioactivity in large tracts of land. In-situ gamma spectroscopy or sampling followed by laboratory measurement

    International Nuclear Information System (INIS)

    In the process of decommissioning contaminated facilities, and in the conduct of normal operations involving radioactive material, it is frequently required to show that large areas of land are not contaminated, or if contaminated that the amount is below an acceptable level. However, it is quite rare for the radioactivity in the soil to be uniformly distributed. Rather it is generally in a few isolated and probably unknown locations. One way to ascertain the status of the land concentration is to take soil samples for subsequent measurement in the laboratory. Another way is to use in-situ gamma spectroscopy. In both cases, the non-uniform distribution of radioactivity can greatly compromise the accuracy of the assay, and makes uncertainty estimates much more complicated than simple propagation of counting statistics. This paper examines the process of determining the best way to estimate the activity on the tract of land, and gives quantitative estimates of measurement uncertainty for various conditions of radioactivity. When the distribution of radioactivity in the soil is not homogeneous, the sampling uncertainty is likely to be larger than the in-situ measurement uncertainty. (author)

  10. X-ray and {Gamma}-ray spectroscopy of solids under pressure. Annual technical progress report, November 1996--October 1997

    Energy Technology Data Exchange (ETDEWEB)

    Ingalls, R.L.

    1997-04-30

    This report describes our recent synchrotron x-ray absorption fine structure (XAFS) measurements on a number of systems that undergo pressure induced changes in local structure at high pressure. Our general technique is based upon a pressure cell which utilizes scintered boron carbide anvils, since diamond anvils generally produce Bragg glitches which spoil the high quality EXAFS necessary for precision structural measurements. Sample pressure is determined at the beam-line by measuring and analyzing, via XAFS, the compression of some cubic material contained within the sample chamber. Recently we have extended this work to 77 K using helium gas for the applied force, rather than hydraulic oil.

  11. Gamma ray spectroscopy employing divalent europium-doped alkaline earth halides and digital readout for accurate histogramming

    Energy Technology Data Exchange (ETDEWEB)

    Cherepy, Nerine Jane; Payne, Stephen Anthony; Drury, Owen B.; Sturm, Benjamin W.

    2016-02-09

    According to one embodiment, a scintillator radiation detector system includes a scintillator, and a processing device for processing pulse traces corresponding to light pulses from the scintillator, where the processing device is configured to: process each pulse trace over at least two temporal windows and to use pulse digitization to improve energy resolution of the system. According to another embodiment, a scintillator radiation detector system includes a processing device configured to: fit digitized scintillation waveforms to an algorithm, perform a direct integration of fit parameters, process multiple integration windows for each digitized scintillation waveform to determine a correction factor, and apply the correction factor to each digitized scintillation waveform.

  12. IR double-resonance spectroscopy applied to the 4-aminophenol(H{sub 2}O){sub 1} cluster

    Energy Technology Data Exchange (ETDEWEB)

    Gerhards, M.; Unterberg, C. [Duesseldorf Univ. (Germany). Inst. fuer Physikalische Chemie und Elektrochemie

    2001-03-01

    The IR double-resonance techniques IR/R2PI (infrared/resonant 2-photon ionization), IR/PIRI (infrared-photo-induced Rydberg ionization) and IR-photodissociation spectroscopy are valuable tools to investigate structure, vibrations, and dynamical processes of neutral and ionic hydrogen-bonded clusters containing aromatic molecules. In this paper we report on the application of the IR double-resonance techniques to determine the NH and OH stretching vibrations of 4-aminophenol and 4-aminophenol(H{sub 2}O){sub 1}, both in the neutral (S{sub 0}) and ionic (D{sub 0}) ground state. All vibrational frequencies obtained for 4-aminophenol and the cluster are compared with the values obtained from ab initio and DFT calculations. In the S{sub 0} state, a trans-linear arrangement of 4-aminophenol(H{sub 2}O){sub 1} is obtained containing an O-H. O hydrogen bond. In the D{sub 0} state an overlay of two spectra can be observed resulting from the trans-linear structure and a second structure which contains a N-H. O hydrogen bond. The observation of these two structures within the ion is an interesting example of a rearrangement reaction in the ionic state. (orig.)

  13. Laser Raman spectroscopy and omegatron mass spectrometry applied to investigations of the radiochemical reactions between methane and tritium

    International Nuclear Information System (INIS)

    This paper reports that the radiochemical reactions between methane and tritium were vicariously chosen for the evaluation of an omegatron type mass spectrometer and a laser Raman spectrometer in view of their analytical application in tritium systems. Assessment of the omegatron was extended beyond previous work on the quantitative analysis of all hydrogen isotopes and stable helium isotopes to include the determination of tritiated hydrocarbons. As opposed to mass spectrometry, laser Raman spectroscopy is an absolute method, which in principle is applicable to all polyatomic gases. For the employment in tritium systems an uhv-tight stainless steel gas cell using windows mounted in CF flanges with a flatness better than 1 lambda was constructed and tested. The Raman spectra of H2, HD and D2 were measured and the pure rotation and rotation vibration branches assigned. The fundamental vibrations of methane and deuterated methanes have also been identified. First kinetic data on the β-radiation induced exchange reaction between tritium and methane have been obtained with an omegatron

  14. [Multi-spectroscopy applied to study on a late neolithic colored stone from Yuhui Site in Huaihe Basin].

    Science.gov (United States)

    Wang, Hai-gang; Jin, Zheng-yao; Xie, Zhi; Fan, An-chuan; Yan, Li-feng; Zhu, Bing-quan; Wang, Ji-huai

    2013-09-01

    The unearthing of a large number of red-yellow colored stones in Yuhui Site, Bengbu city, Anhui province of China, which was the only site of Longshan culture appointed by "Origin of the Chinese Civilization Project" in the Huaihe River basin, has drawn a widespread attention in archaeology. The present research was undertaken to examine elements, mineral composition and thermal history of one red-yellow color stone in different positions, classified according to specialized colors, by means of synchrotron radiation X-ray fluorescence (SR-XRF), X-ray diffraction (XRD), laser Raman spectroscopy (LRS), electron probe micro-analysis (EPMA) and thermoluminescence (TL). The results show that the main body of the color stone is limonite with a large amount of quartz inclusion. The yellow substances on the surface layer of the color stone were identified as goethite (alpha-FeOOH), and the red ones as red ochre (alpha-Fe2O3+clay+silica). The internal yellow brown substances inside the stone are mainly aphanitic goethite with a number of chromites and manganese dioxide, and also with small quantity of barite and bismuth. And the color stones are without historical firing treatment. These kinds of special polymetallic ores with unique nature and complex geologic history, which were unearthed in the late neolithic site with large numbers, may be closely related to some kind of primitive religious beliefs and special sacrificial practices. PMID:24369621

  15. Fast label-free detection of Legionella spp. in biofilms by applying immunomagnetic beads and Raman spectroscopy.

    Science.gov (United States)

    Kusić, Dragana; Rösch, Petra; Popp, Jürgen

    2016-03-01

    Legionellae colonize biofilms, can form a biofilm by itself and multiply intracellularly within the protozoa commonly found in water distribution systems. Approximately half of the known species are pathogenic and have been connected to severe multisystem Legionnaires' disease. The detection methods for Legionella spp. in water samples are still based on cultivation, which is time consuming due to the slow growth of this bacterium. Here, we developed a cultivation-independent, label-free and fast detection method for legionellae in a biofilm matrix based on the Raman spectroscopic analysis of isolated single cells via immunomagnetic separation (IMS). A database comprising the Raman spectra of single bacterial cells captured and separated from the biofilms formed by each species was used to build the identification method based on a support vector machine (SVM) discriminative classifier. The complete method allows the detection of Legionella spp. in 100 min. Cross-reactivity of Legionella spp. specific immunomagnetic beads to the other studied genera was tested, where only small cell amounts of Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli compared to the initial number of cells were isolated by the immunobeads. Nevertheless, the Raman spectra collected from isolated non-targeted bacteria were well-discriminated from the Raman spectra collected from isolated Legionella cells, whereby the Raman spectra of the independent dataset of Legionella strains were assigned with an accuracy of 98.6%. In addition, Raman spectroscopy was also used to differentiate between isolated Legionella species. PMID:26915495

  16. Deep-inelastic heavy-ion collisions at the Tandem accelerator in Orsay - Gamma spectroscopy of fp-shell neutron-rich nuclei with the ORGAM germanium array detector

    International Nuclear Information System (INIS)

    The work presented here aimed at producing neutron rich fp shell nuclei through heavy ion collisions at the Tandem accelerator of IPN, and to study them using gamma spectroscopy. For this purpose, a germanium gamma array called ORGAM, and dedicated to high resolution gamma spectroscopy, was set up at the Tandem accelerator. During the year 2008/2009, the individual germanium detectors were tested and repaired, as well as their ancillary anti-Compton shielding. At the same time, the liquid nitrogen auto-fill system was improved for better reliability. The array was finally set up on a beam line of the accelerator.The first experiment using the ORGAM array was performed in July 2009. This experiment aimed to study fully damped deep-inelastic collisions between a 36S beam accelerated to 154 MeV, and a 70Zn target. An additional charged particle detection system was used to detect interesting fragments emitted at backward angles. It was not possible to separate these fragments from the background induced by backscattered ions from the beam. Nevertheless, the study of gamma-gamma coincidences detected with the ORGAM array allowed to identify gamma cascades de-exciting nuclei potentially produced through the mechanism of interest. Data accumulated during another experiment performed at the tandem accelerator in 2005 were analyzed. Fusion-evaporation reaction between a 25 MeV, 14C beam focused on a 48Ca target produced the 57Cr and 59Mn nuclei, whose energy spectra were established up to 3 MeV. We attempted to study theoretically odd Chromium isotopes with a simple model based on the intermediate coupling scheme. This model, which does not take into account correlations between valence nucleons, described in satisfactory way the semi-magic + 1 neutron, 53Cr, but failed to do so for mid-shell nuclei 55Cr and 57Cr. (author)

  17. Evaluation of the standard normal variate method for Laser-Induced Breakdown Spectroscopy data treatment applied to the discrimination of painting layers

    Science.gov (United States)

    Syvilay, D.; Wilkie-Chancellier, N.; Trichereau, B.; Texier, A.; Martinez, L.; Serfaty, S.; Detalle, V.

    2015-12-01

    Nowadays, Laser-Induced Breakdown Spectroscopy (LIBS) is frequently used for in situ analyses to identify pigments from mural paintings. Nonetheless, in situ analyses require a robust instrumentation in order to face to hard experimental conditions. This may imply variation of fluencies and thus inducing variation of LIBS signal, which degrades spectra and then results. Usually, to overcome these experimental errors, LIBS signal is processed. Signal processing methods most commonly used are the baseline subtraction and the normalization by using a spectral line. However, the latter suggests that this chosen element is a constant component of the material, which may not be the case in paint layers organized in stratigraphic layers. For this reason, it is sometimes difficult to apply this normalization. In this study, another normalization will be carried out to throw off these signal variations. Standard normal variate (SNV) is a normalization designed for these conditions. It is sometimes implemented in Diffuse Reflectance Infrared Fourier Transform Spectroscopy and in Raman Spectroscopy but rarely in LIBS. The SNV transformation is not newly applied on LIBS data, but for the first time the effect of SNV on LIBS spectra was evaluated in details (energy of laser, shot by shot, quantification). The aim of this paper is the quick visualization of the different layers of a stratigraphic painting sample by simple data representations (3D or 2D) after SNV normalization. In this investigation, we showed the potential power of SNV transformation to overcome undesired LIBS signal variations but also its limit of application. This method appears as a promising way to normalize LIBS data, which may be interesting for in-situ depth analyses.

  18. Predicting the origin of soil evidence: High throughput eukaryote sequencing and MIR spectroscopy applied to a crime scene scenario.

    Science.gov (United States)

    Young, Jennifer M; Weyrich, Laura S; Breen, James; Macdonald, Lynne M; Cooper, Alan

    2015-06-01

    Soil can serve as powerful trace evidence in forensic casework, because it is highly individualistic and can be characterised using a number of techniques. Complex soil matrixes can support a vast number of organisms that can provide a site-specific signal for use in forensic soil discrimination. Previous DNA fingerprinting techniques rely on variations in fragment length to distinguish between soil profiles and focus solely on microbial communities. However, the recent development of high throughput sequencing (HTS) has the potential to provide a more detailed picture of the soil community by accessing non-culturable microorganisms and by identifying specific bacteria, fungi, and plants within soil. To demonstrate the application of HTS to forensic soil analysis, 18S ribosomal RNA profiles of six forensic mock crime scene samples were compared to those collected from seven reference locations across South Australia. Our results demonstrate the utility of non-bacterial DNA to discriminate between different sites, and were able to link a soil to a particular location. In addition, HTS complemented traditional Mid Infrared (MIR) spectroscopy soil profiling, but was able to provide statistically stronger discriminatory power at a finer scale. Through the design of an experimental case scenario, we highlight the considerations and potential limitations of this method in forensic casework. We show that HTS analysis of soil eukaryotes was robust to environmental variation, e.g. rainfall and temperature, transfer effects, storage effects and spatial variation. In addition, this study utilises novel analytical methodologies to interpret results for investigative purposes and provides prediction statistics to support soil DNA analysis for evidential stages of a case. PMID:25839677

  19. Two-dimensional correlation infrared spectroscopy applied to analyzing and identifying the Radix paeoniae Alba medicinal materials

    Science.gov (United States)

    Liu, Yan; Jun-quan, Wang; Shun-hang, Liu; Sun, Su-Qin

    2008-07-01

    In this paper, we employed Fourier transformation infrared spectroscopy (FTIR) and two-dimensional correlation (2D) technique to analyzing and comparing the Radix paeoniae Alba medicinal materials that provided by Good Agricultural Practice (GAP) base, the market, and China pharmaceutical biological analysis institute whose medicinal material acts as a control group. We compared the infrared spectra of the three samples, and found that they are very similar to each other, the only difference is that the control group has a strong absorbing peak at 1634 cm -1, and the sample from GAP base and suppliers have the same absorbing peak shape at 1627 cm -1 and 1625 cm -1, respectively. The comparison of three second derivative spectra indicating that the characteristic peak of the R. paeoniae Alba that from the base and the market have a one-to-one relationship with that of the control group, but at the range of 900-1200 cm -1 they have different absorbing peaks. More comparisons of 2D IR spectra were done, and the result shows that at the range of 1060-1320 cm -1, the samples from GAP has a high similarity with the control group, but the samples from the suppliers have a distinct difference with the control group. Combining the infrared spectra, second derivative spectra and 2D IR spectra, the samples of the GAP base has a strong relativity with the control group, and the productions from the suppliers have a weak relativity. Comparing with the single index quantitative analysis served by classical Liquid Chromatograph, this method is simple, fast and accurate.

  20. Alpha and gamma spectrometry applied to the study of U and Th series radioactive disequilibrium in the phosphates from Abrolhos Archipelago (Brazil offshore)

    International Nuclear Information System (INIS)

    This paper presents the results of uranium and thorium measurements made in aluminium and iron phosphates that occur in the Abrolhos Archipelago (offshore Brazil) by instrumental neutron activation analysis. The U concentrations were also indirectly determined from the gamma-ray activity of 234 Th, 214 Pb and 214 Bi, while those of Th were obtained from the 228 Ca, 212 Pb, 212 Bi and 208 T1 gamma-ray emitters. In both cases it was assumed that 238 U and 232 Th series are in radioactive secular equilibrium. The comparison between the results obtained by neutron activation and gamma-ray spectrometry show radioactive secular equilibrium in the analysed samples. (author)

  1. Optical emission spectroscopy of microwave-plasmas at atmospheric pressure applied to the growth of organosilicon and organotitanium nanopowders

    Science.gov (United States)

    Kilicaslan, A.; Levasseur, O.; Roy-Garofano, V.; Profili, J.; Moisan, M.; Côté, C.; Sarkissian, A.; Stafford, L.

    2014-03-01

    An atmospheric-pressure plasma sustained by an electromagnetic surface wave (SW) in the microwave regime combined with a bubbler/flash evaporator for the injection of liquid precursors was used to produce organosilicon and organotitanium nanopowders. Following the addition of hexamethyldisiloxane (HMDSO) vapors in the nominally pure argon plasma, optical emission spectra revealed the apparition of strong C2 molecular bands along with Si and Balmer H emission lines. Such features were not observed in our atmospheric-pressure Ar/HMDSO discharges controlled by dielectric barriers, indicating that microwave plasmas are characterized by much higher fragmentation levels of the precursors due to much higher electron densities. Emission spectra from the Ar/HMDSO SW plasma further showed a high-intensity continuum, the intensity of which decreased with time as powders started to form on the discharge tube walls. In presence of titanium isopropoxide (TTIP) vapors in the nominally pure Ar plasma, the emission was dominated by Ar and Ti lines, with no trace of carbon and no continuum. Fourier-Transform Infrared (FTIR) Spectroscopy of the powders formed in Ar/HMDSO plasmas showed very strong Si-(CH3)x and O-Si-(CH3)x bands, which is consistent with the formation of silicon oxycarbide. Transmission Electron Microscopy (TEM) further showed tube and sheet-like nanofeatures as well as larger structures consisting of agglomerated primary clusters. On the other hand, introduction of O2 in Ar/HMDSO plasmas produced only round-like nanoparticles with strong Si-O-Si bands and no trace of carbon, consistent with the formation of SiOx. The average size of the silica nanoparticles was 50 nm. FTIR spectra of powders formed in Ar/TTIP plasmas showed strong Ti-O signals, even without the addition of O2 in the gas phase. Corresponding TEM analysis showed nano- and agglomerated features comparable to those obtained in Ar/HMDSO although the average size of the titanate nanoparticles was smaller

  2. Optical emission spectroscopy of microwave-plasmas at atmospheric pressure applied to the growth of organosilicon and organotitanium nanopowders

    Energy Technology Data Exchange (ETDEWEB)

    Kilicaslan, A.; Levasseur, O.; Roy-Garofano, V.; Profili, J.; Moisan, M.; Stafford, L., E-mail: luc.stafford@umontreal.ca [Département de Physique, Université de Montréal, Montréal, Québec H3C 3J7 (Canada); Côté, C.; Sarkissian, A. [Plasmionique Inc., Varennes, Québec J3X 1S2 (Canada)

    2014-03-21

    An atmospheric-pressure plasma sustained by an electromagnetic surface wave (SW) in the microwave regime combined with a bubbler/flash evaporator for the injection of liquid precursors was used to produce organosilicon and organotitanium nanopowders. Following the addition of hexamethyldisiloxane (HMDSO) vapors in the nominally pure argon plasma, optical emission spectra revealed the apparition of strong C{sub 2} molecular bands along with Si and Balmer H emission lines. Such features were not observed in our atmospheric-pressure Ar/HMDSO discharges controlled by dielectric barriers, indicating that microwave plasmas are characterized by much higher fragmentation levels of the precursors due to much higher electron densities. Emission spectra from the Ar/HMDSO SW plasma further showed a high-intensity continuum, the intensity of which decreased with time as powders started to form on the discharge tube walls. In presence of titanium isopropoxide (TTIP) vapors in the nominally pure Ar plasma, the emission was dominated by Ar and Ti lines, with no trace of carbon and no continuum. Fourier-Transform Infrared (FTIR) Spectroscopy of the powders formed in Ar/HMDSO plasmas showed very strong Si-(CH{sub 3}){sub x} and O-Si-(CH{sub 3}){sub x} bands, which is consistent with the formation of silicon oxycarbide. Transmission Electron Microscopy (TEM) further showed tube and sheet-like nanofeatures as well as larger structures consisting of agglomerated primary clusters. On the other hand, introduction of O{sub 2} in Ar/HMDSO plasmas produced only round-like nanoparticles with strong Si-O-Si bands and no trace of carbon, consistent with the formation of SiO{sub x}. The average size of the silica nanoparticles was 50 nm. FTIR spectra of powders formed in Ar/TTIP plasmas showed strong Ti-O signals, even without the addition of O{sub 2} in the gas phase. Corresponding TEM analysis showed nano- and agglomerated features comparable to those obtained in Ar/HMDSO although the

  3. Near-infrared spectroscopy combined with equidistant combination partial least squares applied to multi-index analysis of corn

    Science.gov (United States)

    Lyu, Ning; Chen, Jiemei; Pan, Tao; Yao, Lijun; Han, Yun; Yu, Jing

    2016-05-01

    Development of small, dedicated, reagentless, and low-cost spectrometer has broad application prospects in large-scale agriculture. An appropriate wavelength selection method is a key, albeit difficult, technical aspect. A novel wavelength selection method, named equidistant combination partial least squares (EC-PLS), was applied for wavenumber selection for near-infrared analysis of crude protein, moisture, and crude fat in corn. Based on the EC-PLS, a model set that includes various models equivalent to the optimal model was proposed to select independent and joint-analyses models. The independent analysis models for crude protein, moisture, and crude fat contained only 16, 12, and 22 wavenumbers, whereas the joint-analyses model for the three indicators contained only 27 wavenumbers. Random validation samples excluded from the modeling process were used to validate the four selected models. For the independent analysis models, the validation root mean square errors (V_SEP), validation correlation coefficients (V_RP), and relative validation root mean square errors (V_RSEP) of prediction were 0.271%, 0.946, and 2.8% for crude protein, 0.275%, 0.936, and 2.6% for moisture, and 0.183%, 0.924, and 4.5% for crude fat, respectively. For the joint-analyses model, the V_SEP, V_RP, and V_RSEP were 0.302%, 0.934, and 3.2% for crude protein, 0.280%, 0.935, and 2.7% for moisture, and 0.228%, 0.910, and 5.6% for crude fat, respectively. The results indicated good validation effects and low complexity. Thus, the established models were simple and efficient. The proposed wavenumber selection method provided also valuable reference for designing small dedicated spectrometer for corn. Moreover, the methodological framework and optimization algorithm are universal, such that they can be applied to other fields.

  4. Radioimmunoassay (RIA), radioreceptorassay (RRA) and atomic absorption spectroscopy (AAS) applied to studies on animal nutrition and health

    International Nuclear Information System (INIS)

    In 1990, our group began working in the development of a sensitive method to measure the active principle (1,25 dihydroxy-vitamin D3-glycoside) of Solanum glaucophyllum, a plant that grows wild in our country causing calcinosis of breeding cattle. RIA and RRA have been applied to determine this glycoside in the aqueous extracts of the plant leaves and the free vitamin D metabolite in animal plasma samples, respectively. AAS was also used to determine calcium, together with phosphorus determined by colorimetric methods, in blood and tissues of experimental animals in order to study the relationship between the active principle kinetics and its effects. More recently, this plant has been proposed as a source of vitamin D activity (VDA) that might contribute with environment care improving calcium and phosphorus utilization by animals. Our group is by now, as a first step, studying the effects of different diet levels of calcium (Ca) and phosphorus (P) [covering the range between commercial recommendations and half of NRC requirements (1994)], as well as different sources of those minerals, upon productive, nutritional, skeletal and biochemical parameters, in a series of experiments covering either a part or the entire breeding cycle of broilers. We think that the high levels of vitamin D3 employed in commercial farms (4 times NRC recommendations) could enable birds fed on basal diets to enhance the synthesis of the active metabolite of the vitamin in order to overcome partially these minerals deficiency. These methods of analysis have been applied successfully in our research projects contributing to the improvement of animal health and production and our approach has been considered adequate for the study of this additive and therefore has been required by the private industry of foreign countries. (author)

  5. Impedance spectroscopy applied to the fast wounding dynamics of an electrical wound-healing assay in mammalian cells

    International Nuclear Information System (INIS)

    Electrical wound-healing assays are often used as a means to study in vitro cell migration and proliferation. In such analysis, a cell monolayer that sits on a small electrode is electrically wounded and its spectral impedance is then continuously measured in order to monitor the healing process. The relatively slow dynamics of the cell healing have been extensively studied, while those of the much faster wounding phase have not yet been investigated. An analysis of the electrical properties of a particular cell type during this phase could give extra information about the changes in the cell membrane due to the application of the wounding current, and could also be useful to optimize the wounding regime for different cell types. The main issue when trying to register information about these dynamics is that the traditional measurement scheme employed in typical wound-healing assays doesn’t allow the simultaneous application of the wounding signal and measurement of the system’s impedance. In this paper, we overcome this limitation by implementing a measurement strategy consisting of cycles of fast alternating low- and high-voltage signals applied on electrodes covered with mammalian cells. This approach is capable of registering the fast impedance changes during the transient regime corresponding to the cell wounding process. Furthermore, these quasi-simultaneous high- and low-voltage measurements can be compared in order to obtain an empirical correlation between both quantities. (paper)

  6. High-sensitivity gamma spectroscopy for extended sources. Application to activity measurements on the human body, on glass, and on soil; Spectrographie gamma a grande sensibilite pour sources etendues. Application a la mesure de l'activite du corps humain, du verre et du sol

    Energy Technology Data Exchange (ETDEWEB)

    Jouve, B

    1962-07-01

    The measurement and location by gamma spectroscopy of human body internal contaminations at maximum permissible levels, and, in certain cases, at lower activities such as that due to {sup 40}K was investigated. The characteristics of the high-sensitivity apparatus used are given, and several assemblies using large-volume NaI(Tl) scintillators are described. The relatively light shielding required for natural radioactivity permitted construction of mobile assembly. Conditions of use are described, and the results are given. All gamma emitting elements were measured in 15 min at levels lower than the tolerance dose. Gamma spectroscopy was also used to determine fission products in the earth and to study radioactive elements in the presence of other emitters. (author) [French] La spectrographie gamma du corps humain permet la mesure et la localisation des contaminations internes au niveau des doses de tolerance et, dans certains cas, celle d'activites plus faibles comme la radioactivite naturelle due principalement au potassium 40. Les caracteristiques des appareils a grande sensibilite permettant ces mesures sont exposees et on decrit plusieurs realisations originales utilisant un scintillateur NaI(Tl) de grand volume. L'epaisseur du blindage a ete limitee a 5 cm de plomb, ainsi, pour une protection suffisante contre les rayonnements ambiants, les appareils sont relativement legers et l'une des realisations a pu etre installee dans un laboratoire mobile. Les conditions d'utilisation (mouvement propre, etalonnage) et les resultats obtenus sont donnes; tous les radioelements emetteurs gamma sont mesurables en 15 minutes a un niveau inferieur a la dose de tolerance. On presente enfin des applications a la spectrographie gamma d'echantillons volumineux (poudres ou liquides) et de tres faible activite: elles interessent des domaines tres varies comme, par exemple, la geophysique (etude des retombees radioactives) ou l'industrie chimique

  7. Gamma-Ray Interactions for Reachback Analysts

    Energy Technology Data Exchange (ETDEWEB)

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Myers, Steven Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-02

    This presentation is a part of the DHS LSS spectroscopy training course and presents an overview of the following concepts: identification and measurement of gamma rays; use of gamma counts and energies in research.

  8. Investigation of hyperfine parameters of semiconductor oxides SnO2 and TiO2 pure and doped with 3d transition methods using spectroscopy of perturbed gamma-gamma angular correlation

    International Nuclear Information System (INIS)

    This study aimed the use of nuclear technique Perturbed γ-γ Angular Correlation Spectroscopy (PAC) to measure the hyperfine interactions in thin films and powder samples of SnO2 and TiO2 pure and doped with transition metals to obtain a systematic investigation of defects and magnetism from an atomic point of view with the main motivation the application in spintronics. The work also focused on the preparation and characterization of samples by conventional techniques such as X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and magnetization measurements. Pure samples of the films were measured by the systematic variation of thermal treatment and applied magnetic field. These measurements were performed in HISKP at the University of Bonn (Rheinische Friedrich-Wilhelms-Universität Bonn) using 111In(111Cd) or 181Hf (181Ta); at IPEN, in turn, these measurements were performed after the diffusion of the same probe nuclei. Another part of PAC measurements were carried out using 111mCd(111Cd) and 117Cd (117In) in Isotope Mass Separator On-Line (ISOLDE) at Centre Européen Recherche Nucléaire (CERN). The measurements were performed from 8 K to 1173 K. After comparing results from macroscopic techniques with those from PAC, it was concluded that there is a correlation between the defects, magnetism and the mobility of charge carriers in semiconductors studied here. A step forward in the search for semiconductors, whose magnetic ordering allows its use in electronics based on spin. Some results have been published, including results obtained at the University of Bonn for the sandwich doctorate period [1-7]. (author)

  9. In-beam gamma-ray spectroscopy of neutron-rich nuclei using fragmentation of radioactive beams and half-lives measurements of excited levels in nuclei closed to {sup 68}Ni; Spectroscopie {gamma} en ligne de noyaux legers riches en neutrons produits par fragmentation de faisceau radioactif et mesures de temps de vie des niveaux excites dans des noyaux proches de {sup 68}Ni

    Energy Technology Data Exchange (ETDEWEB)

    Stanoiu, M.A

    2003-01-01

    This thesis deals with studies of nuclei far from the valley of stability produced at GANIL by projectile fragmentation at intermediate energies. It consists of two parts. The first one is dedicated to the study of very light exotic nuclei around N=14. This is the first time that online {gamma}-ray spectroscopy combined with the projectile fragmentation was used with radioactive incident beams at GANIL. The advantages and the limitations of this method were established. 40 different nuclei have been produced and studied at the same time. A strong dependence of the population of excited states on the type of projectile was observed. New information was obtained on the structure of the isotopes B{sup 14,15}, C{sup 17,18,19,20}, N{sup 18,19,20,21,22}, O{sup 22,23,24}, F{sup 24,25,26} and Ne{sup 29}. The level schemes obtained from this study have been compared with shell-model predictions. In particular, the energy of 1588(20) keV found for the first 2{sup +} excited state in C{sup 20}, as well as the non-existence of a bound state in O{sup 24}, show that the proton-neutron interaction plays an important role in the structure of these nuclei. In the second part, an experiment is presented concerning the neutron-rich isomer nuclei around Ni{sup 68} produced by the LISE spectrometer. The fast-timing method was applied for the first time for the study of nuclei produced by projectile fragmentation. Subnanosecond half-lives of several levels in Ni{sup 67,69,90} and Cu{sup 71,72} were measured simultaneously and with high precision. These results have allowed us to test the shell model predictions for several E2 transitions and their associated B(E2) transition probabilities. (author)

  10. Gamma-ray spectrometry applied to agricultural soil in the northwest of the State of Rio de Janeiro; Gamaespectrometria aplicada em solo agricola no noroeste do Estado do Rio de Janeiro

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Andrea Cristina Lima dos; Nascimento, Carlos Tadeu Carvalho do [Instituto de Geociencias, Universidade de Brasilia, DF (Brazil); Menezes, Paulo de Tarso Luiz, E-mail: andrealima@unb.br, E-mail: carlostadeu@unb.br, E-mail: ptarsomenezes@pq.cnpq.br [Faculdade de Geologia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    2008-04-15

    The present work presents the use of gamma-ray spectrometry applied to precision agriculture in a sub-tropical area. Our dataset comprises measurements both in rock and residual soil. The soil dataset shows a reduction of 20% on U and Th and 10% on K, when compared to rock samples. This difference could be related to K supplementation associated to chemical fertilization. (author)

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

    OpenAIRE

    Belley, Matthew D.; Segars, William Paul; Kapadia, Anuj J.

    2014-01-01

    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.

  12. Study of neutron-rich nuclei structure around the N=28 shell closure using the in-beam gamma spectroscopy technique; Etude de la structure des noyaux riches en neutrons autour de la fermeture de couches N=28 par spectroscopie gamma en ligne

    Energy Technology Data Exchange (ETDEWEB)

    Bastin, B

    2007-10-15

    For a few years now, a loss of magicity in neutron-rich nuclei near the neutron drip-line at N=28 has been suggested and observed. Deformation in these nuclei has been observed. The deformation was explained in S isotopes as being due to a moderate reduction of the N=28 shell closure together with a proton induced collectivity originating from the near degeneracy of the proton d3/2 and s1/2 orbitals. As a consequence, the observed deformation seems to result from a subtle interplay between neutron and proton excitations. Since the proton configuration in the Si isotopes is expected to be more stable due to the Z=14 sub-shell gap, {sup 42}Si was considered as a key nucleus in order to distinguish the different effects responsible for the structural changes observed at N=28. Even if it is at the limits of our technical possibilities, an in-beam gamma-spectroscopy experiment using two-step fragmentation and one or several nucleons knockout reaction mechanisms was performed at GANIL. The measurement of the energy of the first excited state in {sup 42}Si, combined with the observation of {sup 38,40}Si and the spectroscopy of {sup 41,43}P, has given evidence for the loss of magicity at N=28 far from stability. Modifications of the effective interaction used in modern shell model calculations have been completed following this investigation, increasing its predictive character. This study confirms the role of the tensor force and the density dependence of the spin-orbit interaction in the collapse of the N=28 shell closure. (author)

  13. Report on research in progress in the nuclear spectroscopy area : reactions and structure

    Energy Technology Data Exchange (ETDEWEB)

    Helene, O.A.M.; Borello-Lewin, T.; Seale, W.A. (Sao Paulo Univ. (Brazil). Inst. de Fisica); Saxena, R.N. (Instituto de Pesquisas Energeticas e Nucleares, Sao Paulo (Brazil))

    1982-09-01

    Research on nuclear spectroscopy which are being done by several groups in Brazil are reported. Works, both experimental and theoretical, are divided in particle and gamma spectroscopy and the former has also gamma-gamma angular correlation.

  14. Report on research in progress in the nuclear spectroscopy area : reactions and structure

    International Nuclear Information System (INIS)

    Research on nuclear spectroscopy which are being done by several groups in Brazil are reported. Works, both experimental and theoretical, are divided in particle and gamma spectroscopy and the former has also gamma-gamma angular correlation. (L.C.)

  15. A new radionuclear method for the measurement of the flow of intraocular fluid applying a paperstripe saturated with 22NaCl and a gamma-chamber

    International Nuclear Information System (INIS)

    The first results of this new method are reported. A paperstripe saturated with 22NaCl is put on the cornea and the change of scintillation is measured with a gamma-chamber. The non-invasive method may be of significance in the diagnosis of glaucoma and may be used for the evaluation of glaucoma treatment. (author)

  16. Development of a method for direct gamma-spectroscopy measurements of the gamma-radioactivity of natural waters. Part of a coordinated programme on radiological and environmental protection studies in the Danube river catchment area

    International Nuclear Information System (INIS)

    In the present paper the possibilities of the direct gamma spectrometry in natural waters are discussed. The methods of theoretical and experimental determination of the detector-system sensibility are suggested. Gamma-field spectra taken in natural basins in Bulgaria are given. It is recommended to use the suggested methods in the design of a system for a continuous automatic control of the natural waters radiation purity

  17. Radiological impact of a municipal solid waste landfill on soil and groundwater using 2-D resistivity tomography and gamma ray spectroscopy

    International Nuclear Information System (INIS)

    The radiological impacts of a municipal solid waste landfill on soil and groundwater in Port Harcourt municipality was investigated by integrating 2-D resistivity imaging and gamma-ray spectroscopy. The objective of the study is to determine the lateral and vertical limits of leachate contamination, and to estimate the radioactivity concentrations in soil and groundwater. Results show that the soil and ground water have been contaminated by landfill emissions and radioactive materials throughout the landfill area. The distribution of the contamination is uneven and spotty, both horizontally and vertically, and has penetrated to depths exceeding 31m into the ground water aquifer. The primary contaminants found in the site were leachate, landfill gases, and 40K, 226Ra, and 228Ra radionuclides. The mean absorbed dose rates of 31.98nGy/hr, 10.51nGy/hr and 6.98nGy/hr, and mean dose rate equivalents of 0.28mSv/yr, 0.09mSv/yr and 0.06mSv/yr were obtained for the soil, leachate and water samples, respectively. The mean absorbed and equivalent dose rates in the soil and water samples are greater than their controls, suggesting that the landfill area is contaminated. These results are comparable to those reported for other waste sites in the area and lower than the maximum permitted limits for the general public of 1mSv/yr and 0.1mSv/yr for soil and water, respectively. These therefore, have no immediate radiological health burden on the inhabitants who depend on the soil and groundwater for their crops and potable water supply, except for the effects of disease causing micro-organism and non-methane volatile organic compounds (VOCs) from the leachate. However, with continuous consumption of crop products and intake of groundwater, increase in the activity concentration and dose rates of these radionuclides may occur over time, with adverse effects on humans.

  18. Gamma sterilization

    International Nuclear Information System (INIS)

    The lethal action of gamma radiation is based on the disruption of DNA molecules. The sensitivity of (micro)organisms towards radiation varies. In industrial sterilization generally a radiation dose of 25 kGy is applied. Industrial radiation facilities consist of a radiation source, a biological shield and an automatic transport system. Radiation penetrates from all directions into the product and at all positions approximately the same dose is received. The only variable parameter is the velocity of the transport, which in turn determines the total dose received by the product. A number of provisions ensure that the product receives the correct treatment. Some materials show dose-dependent changes resulting from a radiation treatment. Several manufacturers of plastics offer radiation-stable compositions. Hospitals and other users of an irradiation facility have to ensure that the product they offer for gamma sterilization, can stand a treatment. 6 refs.; 2 figs.; 2 tabs

  19. The Effect of Different Gamma Radiation Doses Applied on Tokak 157/37 Barley (Hordeum vulgare and Karahan 99 Wheat (Triticum aestivum on M1 Generation

    Directory of Open Access Journals (Sweden)

    Yeşim KARA

    2015-01-01

    Full Text Available In this research study, the dose of different gamma radiation on seed germination of Hordeum vulgare TOKAK 157/37 barley kind and KARAHAN 99 wheatTriticum aestivum, and the mechanisms of the dose required to maximize the rate and percentage of germination and increased growth of root, seedling, TAEK was conducted in Ankara. The moisture rate has been %11, the barley and wheat seeds whose germination per cent is 98 % has been irradiated with 9 different doses between 0-600Gy in the centre of 60Co which has 1.92 kGy/h powers. The objective of that work was to evaluate determine the efficient gamma radiation dose and to determine the physiological effects and the action of the processing for gamma radiation in plant kinds. At the laboratory experiment it has been seen that the percentage of germination of rising radiation doses has no effect on M1 generation, but after diminishing of root length and seedling height with rising radiation doses it has been determined that the growth of the first leaf has stopped on the 14th day and this event has been given importance statistically for TOKAK 157/37 barley kind, 50 % efficient dose has been determined as ED50 485 Gy, for KARAHAN 99 wheat kind, 50 % efficient dose has been determined as ED50 370 Gy.

  20. Moessbauer gamma echo

    International Nuclear Information System (INIS)

    By applying stepwise phase modulation of recoilless gamma radiation in a coincidence experiment, constructive interference is produced in transmission geometry between the source and the absorber fields. The resulting regenerated decay signal is called a gamma echo. Here it is demonstrated that during the decay of the 14.4 keV state of 57Fe multiple echo signals can be generated. (orig.)

  1. Multivariate curve resolution applied to in situ X-ray absorption spectroscopy data: An efficient tool for data processing and analysis

    International Nuclear Information System (INIS)

    Highlights: • Use of MCR algorithms to extract component spectra of different kinetic evolution. • Obtaining components and concentration profiles without use of reference spectra. • Automatic extraction of meaningful component profiles from large XAS datasets. - Abstract: Large datasets containing many spectra commonly associated with in situ or operando experiments call for new data treatment strategies as conventional scan by scan data analysis methods have become a time-consuming bottleneck. Several convenient automated data processing procedures like least square fitting of reference spectra exist but are based on assumptions. Here we present the application of multivariate curve resolution (MCR) as a blind-source separation method to efficiently process a large data set of an in situ X-ray absorption spectroscopy experiment where the sample undergoes a periodic concentration perturbation. MCR was applied to data from a reversible reduction–oxidation reaction of a rhenium promoted cobalt Fischer–Tropsch synthesis catalyst. The MCR algorithm was capable of extracting in a highly automated manner the component spectra with a different kinetic evolution together with their respective concentration profiles without the use of reference spectra. The modulative nature of our experiments allows for averaging of a number of identical periods and hence an increase in the signal to noise ratio (S/N) which is efficiently exploited by MCR. The practical and added value of the approach in extracting information from large and complex datasets, typical for in situ and operando studies, is highlighted

  2. Impact of metal ions in porphyrin-based applied materials for visible-light photocatalysis: key information from ultrafast electronic spectroscopy.

    Science.gov (United States)

    Kar, Prasenjit; Sardar, Samim; Alarousu, Erkki; Sun, Jingya; Seddigi, Zaki S; Ahmed, Saleh A; Danish, Ekram Y; Mohammed, Omar F; Pal, Samir Kumar

    2014-08-11

    Protoporphyrin IX-zinc oxide (PP-ZnO) nanohybrids have been synthesized for applications in photocatalytic devices. High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and steady-state infrared, absorption, and emission spectroscopies have been used to analyze the structural details and optical properties of these nanohybrids. Time-resolved fluorescence and transient absorption techniques have been applied to study the ultrafast dynamic events that are key to photocatalytic activities. The photocatalytic efficiency under visible-light irradiation in the presence of naturally abundant iron(III) and copper(II) ions has been found to be significantly retarded in the former case, but enhanced in the latter case. More importantly, femtosecond (fs) transient absorption data have clearly demonstrated that the residence of photoexcited electrons from the sensitizer PP in the centrally located iron moiety hinders ground-state bleach recovery of the sensitizer, affecting the overall photocatalytic rate of the nanohybrid. The presence of copper(II) ions, on the other hand, offers additional stability against photobleaching and eventually enhances the efficiency of photocatalysis. In addition, we have also explored the role of UV light in the efficiency of photocatalysis and have rationalized our observations from femtosecond- to picosecond-resolved studies. PMID:25044047

  3. Impact of metal ions in porphyrin-based applied materials for visible-light photocatalysis: Key information from ultrafast electronic spectroscopy

    KAUST Repository

    Kar, Prasenjit

    2014-07-10

    ProtoporphyrinIX-zinc oxide (PP-ZnO) nanohybrids have been synthesized for applications in photocatalytic devices. High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and steady-state infrared, absorption, and emission spectroscopies have been used to analyze the structural details and optical properties of these nanohybrids. Time-resolved fluorescence and transient absorption techniques have been applied to study the ultrafast dynamic events that are key to photocatalytic activities. The photocatalytic efficiency under visible-light irradiation in the presence of naturally abundant iron(III) and copper(II) ions has been found to be significantly retarded in the former case, but enhanced in the latter case. More importantly, femtosecond (fs) transient absorption data have clearly demonstrated that the residence of photoexcited electrons from the sensitizer PP in the centrally located iron moiety hinders ground-state bleach recovery of the sensitizer, affecting the overall photocatalytic rate of the nanohybrid. The presence of copper(II) ions, on the other hand, offers additional stability against photobleaching and eventually enhances the efficiency of photocatalysis. In addition, we have also explored the role of UV light in the efficiency of photocatalysis and have rationalized our observations from femtosecond- to picosecond-resolved studies. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Low-resolution Spectroscopy of Gamma-ray Burst Optical Afterglows: Biases in the Swift Sample and Characterization of the Absorbers

    Science.gov (United States)

    Fynbo, J. P. U.; Jakobsson, P.; Prochaska, J. X.; Malesani, D.; Ledoux, C.; de Ugarte Postigo, A.; Nardini, M.; Vreeswijk, P. M.; Wiersema, K.; Hjorth, J.; Sollerman, J.; Chen, H.-W.; Thöne, C. C.; Björnsson, G.; Bloom, J. S.; Castro-Tirado, A. J.; Christensen, L.; De Cia, A.; Fruchter, A. S.; Gorosabel, J.; Graham, J. F.; Jaunsen, A. O.; Jensen, B. L.; Kann, D. A.; Kouveliotou, C.; Levan, A. J.; Maund, J.; Masetti, N.; Milvang-Jensen, B.; Palazzi, E.; Perley, D. A.; Pian, E.; Rol, E.; Schady, P.; Starling, R. L. C.; Tanvir, N. R.; Watson, D. J.; Xu, D.; Augusteijn, T.; Grundahl, F.; Telting, J.; Quirion, P.-O.

    2009-12-01

    We present a sample of 77 optical afterglows (OAs) of Swift detected gamma-ray bursts (GRBs) for which spectroscopic follow-up observations have been secured. Our first objective is to measure the redshifts of the bursts. For the majority (90%) of the afterglows, the redshifts have been determined from the spectra. We provide line lists and equivalent widths (EWs) for all detected lines redward of Lyα covered by the spectra. In addition to the GRB absorption systems, these lists include line strengths for a total of 33 intervening absorption systems. We discuss to what extent the current sample of Swift bursts with OA spectroscopy is a biased subsample of all Swift detected GRBs. For that purpose we define an X-ray-selected statistical sample of Swift bursts with optimal conditions for ground-based follow-up from the period 2005 March to 2008 September; 146 bursts fulfill our sample criteria. We derive the redshift distribution for the statistical (X-ray selected) sample and conclude that less than 18% of Swift bursts can be at z > 7. We compare the high-energy properties (e.g., γ-ray (15-350 keV) fluence and duration, X-ray flux, and excess absorption) for three subsamples of bursts in the statistical sample: (1) bursts with redshifts measured from OA spectroscopy; (2) bursts with detected optical and/or near-IR afterglow, but no afterglow-based redshift; and (3) bursts with no detection of the OA. The bursts in group (1) have slightly higher γ-ray fluences and higher X-ray fluxes and significantly less excess X-ray absorption than bursts in the other two groups. In addition, the fractions of dark bursts, defined as bursts with an optical to X-ray slope βOX 39% in group (3). For the full sample, the dark burst fraction is constrained to be in the range 25%-42%. From this we conclude that the sample of GRBs with OA spectroscopy is not representative for all Swift bursts, most likely due to a bias against the most dusty sight lines. This should be taken into

  5. The neutron-gamma Feynman variance to mean approach: gamma detection and total neutron-gamma detection (theory and practice)

    OpenAIRE

    Chernikova, Dina; Axell, Kåre; Avdic, Senada; Pázsit, Imre; Nordlund, Anders

    2014-01-01

    Two versions of the neutron-gamma variance to mean (Feynman-alpha method or Feynman-Y function) formula for either gamma detection only or total neutron-gamma detection, respectively, are derived and compared in this paper. The new formulas have a particular importance for detectors of either gamma photons or detectors sensitive to both neutron and gamma radiation. If applied to a plastic or liquid scintillation detector, the total neutron-gamma detection Feynman-Y expression corresponds to a...

  6. The Effect of Different Gamma Radiation Doses Applied on Tokak 157/37 Barley (Hordeum vulgare) and Karahan 99 Wheat (Triticum aestivum) on M1 Generation

    OpenAIRE

    Kara, Yeşim; Zeynep ERGÜN; Havser ERTEM VAİZOĞULLAR

    2015-01-01

    In this research study, the dose of different gamma radiation on seed germination of Hordeum vulgare TOKAK 157/37 barley kind and KARAHAN 99 wheatTriticum aestivum, and the mechanisms of the dose required to maximize the rate and percentage of germination and increased growth of root, seedling, TAEK was conducted in Ankara. The moisture rate has been %11, the barley and wheat seeds whose germination per cent is 98 % has been irradiated with 9 different doses between 0-600Gy in the centre of 6...

  7. Study of the dehydration process of melanterite under heat treatment and gamma irradiation effects using Moessbauer spectroscopy and thermal analysis measurements

    International Nuclear Information System (INIS)

    Thermal analysis measurements were performed on melanterite, FeS O4. 7 H2 O, with low heating rate at the dehydration temperature range from 340 degree k up to 420 degree K. These measurements showed different decomposition mechanism after gamma irradiation. Moessbauer effect (M E) measurements were carried out on heated melanterite. The change of the values of the Moessbauer parameters indicated the appearance of different hydrates of ferrous sulfate. The activation energy for dehydration was calculated before and after gamma irradiation. A correlation between the irradiation dose and the corresponding thermal energy required for water dehydration is proposed. 6 figs., 1 tab

  8. Crystal growth and thermoluminescence response of NaZr2(PO4)3 at high gamma radiation doses

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •NaZr2(PO4)3 exposed to gamma doses of 10, 30 and 50 MGy. •Gamma radiation produced growth of the crystal size of the NZP. •Morphology changes were reversible by heating. •Linear relationship between the thermoluminescence and the applied gamma dose. •This property could be useful for high-level gamma dosimetry. -- Abstract: This work describes the synthesis and characterization of NaZr2(PO4)3. The stability of this material under high doses of gamma radiation was investigated in the range of 10–50 MGy. Samples of unaltered and gamma irradiated NaZr2(PO4)3 were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermoluminescence. The results showed that while functional groups were not affected by the gamma irradiation, morphology changes were observed with increasing doses of gamma irradiation. The morphology of the non-irradiated compound is agglomerated flakes; however, irradiation at 10 MGy splits the flakes inducing the formation of well-defined cubes. Gamma irradiation induced the crystal size of the NaZr2(PO4)3 to grow. The heat treatment (973 K) of samples irradiated at 50 MGy resulted in the recovery of the original morphology. Furthermore, the thermoluminescence analysis of the irradiated compound is reported

  9. Environmental monitoring (operational period) of the uranium enrichment facility Almirante Alvaro Alberto. Quadrimonthly report of gamma spectroscopy measurements: march to june 1988

    International Nuclear Information System (INIS)

    In this report we present the assessment of the environmental monitoring radiation levels during the operation period of the Uranium Enrichment Facility Almirante Alvaro Alberto from March to July 1988. The purpose was achieved by sampling and analyzing using gamma spectrometry, water and terrestrial and biological indicators. (author)

  10. Study On The Gamma Irradiation Method For Formation Of Biodegradable films Applied In Packaging And Preservation Of Some Preliminary Processed Agricultural Products

    International Nuclear Information System (INIS)

    In this study, the different compositions of starch and polyvinyl alcohol (PVA) were irradiated by gamma radiation for preparation of biodegradable packaging films. The intact and smooth films were formed by irradiation treatment. The gelation of the starch-based films was significantly enhanced by radiation cross linking. Gel fractions of the irradiated films increased with the increasing of radiation dose from 5 to 15 kGy, whereas their enzymatic degradation rate and water vapor transmission rate decreased. The mechanical properties of these cross linked films were also measured and compared to PE films with the same dimension. The results indicated that the radiation treatment has induced the cross linking between starch and PVA and thus improved the functional properties of the conventional starch-based films. (author)

  11. Application of a gamma spectroscopy system to the measurement of neutron cross sections necessary to the development of nuclear energy; Mise au point d'un systeme de spectroscopie pour mesurer des sections efficaces neutroniques applicables a un possible developpement du nucleaire comme source d'energie

    Energy Technology Data Exchange (ETDEWEB)

    Deruelle, O

    2002-09-01

    This work concerns the development of nuclear energy and nuclear waste management in particular. Two parts of this study can be distinguished. In the first part (theoretical), a thorium-plutonium fuel based on MOX and dedicated for PWR was investigated in order to transmute plutonium in a potentially low waste fuel cycle. It was shown that this type of fuel is not regenerative but could be used for a transition to the industrial thorium fuel cycle without building new reactors. Thanks to moderated neutron spectra and high loaded actinide mass in the core, U-233 is quickly created ({approx}300 kg/y) for a loss of about {approx}1200 kg of fissile plutonium. In the second part (experimental), we have developed and built a new reaction chamber to measure neutron cross sections of actinides by alpha-gamma spectroscopy. This experimental device (in principle transportable) was commissioned in the high flux reactor of ILL Grenoble. Neutron flux was measured by gamma spectroscopy of irradiated Al and Co samples and was found to be of the order of 6,0. 10{sup 14} n.cm{sup -2}.s{sup -1} (4%). By the irradiation of 11{mu}g of Am-243 and Pu-242, corresponding capture cross sections were measured in the thermal neutron flux at 50 deg C. These are the results: {sup 243}Am(n,{gamma}) {sup 244fond.}Am = 4,72{+-}1,42b; {sup 243}Am(n,{gamma}) {sup 244total}Am = 74,8{+-}3,25b; {sup 242}Pu (n,{gamma}){sup 243}Pu = 22,7{+-}1,09b. Uncertainties of the measurements are mostly due to the determination of the neutron flux, efficiency of the electronics and ambiguities related to the definition of the area under {alpha}-{gamma} spectra. Although our measured cross sections deviate (by 10-30%) from the corresponding values widely used in evaluated data libraries such as ENDF, JEF and JENDL, in this work we have demonstrated the feasibility and principle of our experimental method. Furthermore, the value for the 243-americium capture cross-section is in very good agreement with the last two

  12. ESR identification of gamma-irradiated albendazole

    Science.gov (United States)

    Çolak, Seyda

    2010-01-01

    The use of ionizing radiation for sterilization of pharmaceuticals is a well-established technology. In the present work, the spectroscopic and kinetic features of the radicals induced in gamma-irradiated solid albendazole samples is investigated at different temperatures in the dose range of 3-34 kGy by electron spin resonance (ESR) spectroscopy. Irradiation with gamma radiation produced two different radical species in albendazole. They were fairly stable at room temperature but relatively unstable above room temperature, giving rise to an unresolved ESR spectrum consisting of three resonance peaks centered at g=2.0057. Decay activation energies of the contributing radical species were calculated to be 47.8 (±13.5) and 50.5 (±9.7) kJ/mol using the signal intensity decay data derived from annealing studies performed at high temperatures. A linear function of the applied dose was found to best describe the experimental dose-response data. Albendazole does not present the characteristics of good dosimetric materials. However, the discrimination of irradiated albendazole from its unirradiated form was possible even 6 months after storage in normal conditions. Based on these findings, it is concluded that albendazole and albendazole-containing drugs can be safely sterilized by gamma radiation and that ESR spectroscopy could be successfully used as a potential technique for monitoring their radiosterilization.

  13. Chemical spectroscopy

    International Nuclear Information System (INIS)

    The purpose of chemical spectroscopy with neutrons is to utilize the dependence of neutron scattering cross-sections on isotope and on momentum transfer (which probes the spatial extent of the excitation) to understand fundamental and applied aspects of the dynamics of molecules and fluids. Chemical spectroscopy is divided into three energy ranges: vibrational spectroscopy, 25-500 MeV, for which much of the work is done on Be-filter analyzer instruments; low energy spectroscopy, less than 25 MeV; and high resolution spectroscopy, less than 1 MeV, which typically is performed on backscattering spectrometers. Representative examples of measurements of the Q-depenence of vibrational spectra, higher energy resolution as well as extension of the Q-range to lower values at high energy transfers, and provisions of higher sensitivities in vibrational spectroscopy are discussed. High resolution, high sensitivity, and polarization analysis studies in low energy spectroscopy are discussed. Applications of very high resolution spectroscopy are also discussed

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

    Energy Technology Data Exchange (ETDEWEB)

    Belley, Matthew D. [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)

    2014-06-15

    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

  15. Nuclear resonance vibrational spectroscopy applied to [Fe(OEP)(NO)] : the vibrational assignments of five-coordinate ferrous heme-nitrosyls and implications for electronic structure.

    Energy Technology Data Exchange (ETDEWEB)

    Lehnert, N.; Galinato, M. I.; Paulat, F.; Richter-Addo, G. B.; Sturhahn, W.; Xu, N.; Zhao, J. (X-Ray Science Division); (Univ. of Michigan); (Univ. of Oklahoma)

    2010-01-01

    This study presents Nuclear Resonance Vibrational Spectroscopy (NRVS) data on the five-coordinate (5C) ferrous heme-nitrosyl complex [Fe(OEP)(NO)] (1, OEP{sup 2-} = octaethylporphyrinato dianion) and the corresponding {sup 15}N{sup 18}O labeled complex. The obtained spectra identify two isotope sensitive features at 522 and 388 cm{sup -1}, which shift to 508 and 381 cm{sup -1}, respectively, upon isotope labeling. These features are assigned to the Fe-NO stretch v(Fe-NO) and the in-plane Fe-N-O bending mode {delta}{sub ip}(Fe-N-O), the latter has been unambiguously assigned for the first time for 1. The obtained NRVS data were simulated using our quantum chemistry centered normal coordinate analysis (QCC-NCA). Since complex 1 can potentially exist in 12 different conformations involving the FeNO and peripheral ethyl orientations, extended density functional theory (DFT) calculations and QCC-NCA simulations were performed to determine how these conformations affect the NRVS properties of [Fe(OEP)NO]. These results show that the properties and force constants of the FeNO unit are hardly affected by the conformational changes involving the ethyl substituents. On the other hand, the NRVS-active porphyrin-based vibrations around 340-360, 300-320, and 250-270 cm{sup -1} are sensitive to the conformational changes. The spectroscopic changes observed in these regions are due to selective mechanical couplings of one component of Eu-type (in ideal D4h symmetry) porphyrin-based vibrations with the in-plane Fe-N-O bending mode. This leads to the observed variations in Fe(OEP) core mode energies and NRVS intensities without affecting the properties of the FeNO unit. The QCC-NCA simulated NRVS spectra of 1 show excellent agreement with experiment, and indicate that conformer F is likely present in the samples of this complex investigated here. The observed porphyrin-based vibrations in the NRVS spectra of 1 are also assigned based on the QCC-NCA results. The obtained force

  16. Gamma-ray spectroscopy for investigation of the co-existence of deformed and spherical states in the magic nucleus of 114Sn

    International Nuclear Information System (INIS)

    The term diagram of the 50114Sn64 magic nucleus could be enlarged by 77 newly identified gamma transitions and 47 novel energy levels identified by way of a gamma-gamma coincidence measurement using the OSIRIS hexahedral spectrometer and by means of the high-spin reaction of 100Mo(18O,4n)114Sn at an injection energy of E(18O) = 70 MeV. Spins up to an excitation energy of ∝ 11.2 MeV and up to a maximum spin of 23 h have been occupied. For identification of the multipolarities of low-intensity γ-transitions which deplete the high-spin states, γγ-angular correlations have been evaluated, and 26 energy levels could be clearly assigned for the first time to measured spin values. For an interpretation of further nuclear structural states of 114Sn theoretical calculation have been made based on the shell model of nucleus. (orig./DG)

  17. Applying the High-Temperature TL in LiF:Mg,Ti to Mixed Thermal Neutron-Gamma Dosimetry - a Review

    International Nuclear Information System (INIS)

    In a recent review article on the subject of High Temperature TL (HTTL) characteristics, criticized the attempts to use the two peak method in mixed field neutron-gamma ray dosimetry, promoting their firm conviction, as also published in an earlier survey by that this issue is unworthy to be investigated. Although it should have been a review, the article concentrates in the corresponding section only on one of our publications on the subject , trying to prove their view through our highly problematic results, as they define it. The ''problematics'' will be dealt with in specific future publications, but in order to present a realistic and balanced range of views on this issue, a comprehensive review of the results published on this topic is to be given. Many works deal with mixed field dosimetric application of the two-peak method, but for the sake of clarity we will concentrate only on the applications of 6LiF for thermal neutron fields, as presented in our publications(

  18. A NIM (Nuclear Instrumentation Module) system conjugated with optional input for pHEMT amplifier for beta and gamma spectroscopy; Um sistema de modulos NIM conjugados com entrada opcional por amplificador pHEMT para espectroscopia beta e gama

    Energy Technology Data Exchange (ETDEWEB)

    Konrad, Barbara; Lüdke, Everton, E-mail: barbarakonradmev@gmail.com, E-mail: eludke@smail.ufsm.br [Universidade Federal de Santa Maria (LAE/UFSM), RS (Brazil). Lab. de Astrofisica e Eletronica

    2014-07-01

    This work presents a high speed NIM module (Nuclear Instrumentation Module) to detect radiation, gamma and muons, as part of a system for natural radiation monitoring and of extraterrestrial origin. The subsystem developed consists of a preamplifier and an integrated SCA (Single Channel Analyzer), including power supplies of ± 12 and ± 24V with derivations of +3.6 and ± 5V. The single channel analyzer board, consisting of discrete logic components, operating in window modes, normal and integral. The pulse shaping block is made up of two voltage comparators working at 120 MHz with a response time > 60 ns and a logic anticoincidence system. The preamplifier promotes a noise reduction and introduces the impedance matching between the output of anode / diode photomultiplier tubes (PMTs) and subsequent equipment, providing an input impedance of 1MΩ and output impedance of 40 to 140Ω. The shaper amplifier is non-inverting and has variable input capacitance of 1000 pF. The upper and lower thresholds of the SCA are adjustable from 0 to ± 10V, and the equipment is compatible with various types of detectors, like PMTs coupled to sodium iodide crystals. For use with liquid scintillators and photodiodes with crystals (CsI: Tl) is proposed to include a preamplifier circuit pHEMT (pseudomorphic High Electron Mobility Transistor) integrated. Yet, the system presents the possibility of applications for various purposes of gamma spectroscopy and automatic detection of events producing of beta particles.

  19. Determination of Counting Time for the Small Amount of Cesium-137 in Milk Powder and Parboiled Rice Samples by Using Gamma-Ray Spectroscopy

    International Nuclear Information System (INIS)

    Full text: Cesium-137 concentrations in milk powder (n=6) and parboiled rice (n=1) contained in Marinelli beaker (1 liter) were determined using two sets of High Purity Germanium gamma spectrometry systems. Correlation graphs between counting time and Minimum Detectable Concentration (MDC) were obtained by varying and increasing counting time (1000 seconds) when identical samples were repeatedly measured. The counting time ranged from 1000 to 50000 seconds. From the correlation graphs, mathematic equations were generated and used to estimate both appropriate sample counting time and MDC. The result showed that MDCs were not significantly different when the samples were measured at 15000 seconds or even longer

  20. A study of the radiation chemistry of poly(chlorotrifluoroethylene) by ESR spectroscopy[Poly(chlorotrifluoroethylene); {gamma}-radiolysis; ESR study; Radicals; G-values

    Energy Technology Data Exchange (ETDEWEB)

    Hill, D.J.T. E-mail: hill@chemistry.uq.edu.au; Thurecht, K.J.; Whittaker, A.K

    2003-12-01

    The ESR spectra of poly(chlorotrifluoroethylene) were recorded following {gamma}-radiolysis under vacuum at room temperature and 77 K. The very broad spectrum at 77 K revealed little fine structure with which to identity the radicals formed upon irradiation, but subsequent photobleaching and annealing studies, together with radiolytic studies at higher temperatures, afforded scope for making radical assignments. Both main-chain radicals and a range of chain-end radicals have been identified. The G-values for radical formation were 1.55, 0.36 and 0.32 at 77 K, 273 K and room temperature, respectively.

  1. Probing the wind-wind collision in Gamma Velorum with high-resolution Chandra X-ray spectroscopy: evidence for sudden radiative braking and non-equilibrium ionization

    OpenAIRE

    Henley, D. B.; Stevens, I. R.; Pittard, J. M.

    2004-01-01

    We present a new analysis of an archived Chandra HETGS X-ray spectrum of the WR+O colliding wind binary Gamma Velorum. The spectrum is dominated by emission lines from astrophysically abundant elements: Ne, Mg, Si, S and Fe. From a combination of broad-band spectral analysis and an analysis of line flux ratios we infer a wide range of temperatures in the X-ray emitting plasma (~4-40 MK). As in the previously published analysis, we find the X-ray emission lines are essentially unshifted, with ...

  2. Gamma spectrometry of infinite 4Π geometry

    International Nuclear Information System (INIS)

    Owing to the weak absorption og gamma radiation by matter, gamma-ray spectrometry may be applied to samples of great volume. A very interesting case is that of the gamma-ray spectrometry applied with 4Π geometry around the detector on a sample assumed to be of infinite extension. The determination of suitable efficiencies allows this method to be quantitative. (author)

  3. High-precision gamma-ray spectroscopy of 82Rb and 72As, two important medical isotopes used in positron emission tomography

    Science.gov (United States)

    Nino, Michael; McCutchan, E.; Smith, S.; Sonzogni, A.; Muench, L.; Greene, J.; Carpenter, M.; Zhu, S.; Lister, C.

    2015-10-01

    Both 82Rb and 72As are very important medical isotopes used in imaging procedures, yet their full decay schemes were last studied decades ago using low-sensitivity detection systems; high quality decay data is necessary to determine the total dose received by the patient, the background in imaging technologies, and shielding requirements in production facilities. To improve the decay data of these two isotopes, sources were produced at the Brookhaven Linac Isotope Producer (BLIP) and then the Gammasphere array, consisting of 89 Compton-suppressed HPGe detectors, at Argonne National Laboratory was used to analyze the gamma-ray emissions from the daughter nuclei 82 Kr and 72 Ge. Gamma-ray singles and coincidence information were recorded and analyzed using Radware Gf3m software. Significant revisions were made to the level schemes including the observation of many new transitions and levels as well as a reduction in uncertainty on measured γ-ray intensities and deduced β-feedings. The new decay schemes as well as their impact on dose calculations will be presented. DOE Isotope Program is acknowledged for funding ST5001030. Work supported by the U.S. DOE under Grant No. DE-FG02-94ER40848 and Contract Nos. DE-AC02-98CH10946 and DE-AC02-06CH11357 and by the Science Undergraduate Laboratory Internships Program (SULI).

  4. Gamma-thermoluminescence dating (GAMMA-TL)

    International Nuclear Information System (INIS)

    The experimental simplification of the TL dating method is one of the CRIAA Laboratory research fields in physics applied to archaeology. For radiochemical homogeneous systems GAMMA-TL allows a significant simplification for the measurement of the natural dose-rate I while preserving an accuracy as good as the one of classical TL dating within certain limiting circumstances. For instance, in the case of large heated structures determination of I reduces to Isub(γ) on site measurement and to k determination. The annual dose-rate is then given by I = GAMMA(k)Isub (γ) with GAMMA(k) = 12.17 k + 2.72. However, it is necessary to test the hypothesis that radioactivity in the structure is homogeneous. For this purpose high resolution γ spectrometry is used as a routine laboratory technique applied to several similar samples of structure. The comparison between the natural γ-ray criteria for the GAMMA-TL method, since for constant conditions, γ-ray intensities must be identical from one sample to another. We are now investigating structures of known age in order to find within what limits the GAMMA-TL can be used. (author)

  5. Evaluation of Software to Nondestructively Quantify Uranium and Plutonium Samples via Gamma Ray Spectroscopy at the Joint Research Center in Ispra, Italy

    International Nuclear Information System (INIS)

    In March, 2001 at the Joint Research Center in Ispra Italy, an evaluation measurement exercise was undertaken by the Inst. de Radioprotection et de Surete nucleaire (IRSN), for the evaluation of software used for the nondestructive analysis of special nuclear material held by the Joint Research Center. Staff of IRSN and ORTEC measured and analyzed well-characterized uranium and plutonium samples at the JRC PERLA facility, Ispra. Three of the codes evaluated were GammaVision (Version 5.1), 1 ISOTOPIC (Version 2.0.6.2), 2 and PC/FRAM (Version 2.3). 3 GammaVision was used to determine the primary activities relative to a certified calibration point source. ISOTOPIC used modeling to compute correction factors for attenuation and geometry to determine gram quantities of each nuclide following the GammaVision analysis. PC/FRAM was used to determine isotopic ratios or weight percent of the plutonium isotopes. Information from this exercise was used to determine accuracy estimates for inspection teams who would use these methods to measure and analyze uranium and plutonium samples of similar composition at French nuclear sites. Samples selected by the Joint Research Center were measured and analyzed as unknowns. Average uncertainties were determined for homogenous material consisting of UO2, U3O8, PuO2 and MOX (mixed oxides of uranium and plutonium). Several nonhomogeneous samples were prepared in order to simulate containers of radioactive waste. The GammaVision measurement system was calibrated using a traceable 152Eu point source. Geometry corrections were then performed to relate the item being measured to the point source. Isotopic used these results and modeled the actual sample to realistically reflect the volume and attenuation characteristics. ISOTOPIC possesses a 'fine-tune' adjustment: which assumes that activity calculated from individual lines of nuclides with multiple gamma rays must be the same if the correction factors for density, weight fraction uranium

  6. X-ray remote sensing and in-situ spectroscopy for planetary exploration missions and gamma-ray remote sensing and in-situ spectroscopy for planetary exploration missions

    Science.gov (United States)

    Mahdavi, M.; Giboni, K. L.; Vajda, S.; Schweitzer, J.

    1994-01-01

    Detectors that will be used for planetary missions must have their responses calibrated in a reproducible manner. A calibration facility is being constructed at Schlumberger-Doll Research for gamma and x ray detectors. With this facility the detector response can be determined in an invariant and reproducible fashion. Initial use of the facility is expected for the MARS94 detectors. Work is continuing to better understand the rare earth oxyorthosilicates and to define their characteristics. This will allow a better use of these scintillators for planetary missions. In a survey of scintillating materials two scintillators were identified as promising candidates besides GSO, LSO, and YSO. These are CdWO4 and CsI(Tl). It will be investigated if a detector with a better overall performance can be assembled with various photon converters. Considerable progress was achieved in photomultiplier design. The length of an 1 inch diameter PMT could be reduced from 4.2 to 2.5 inches without performance degradation. This technology is being employed in the gamma ray detector for the NEAR project. A further weight and size reduction of the detector package can be achieved with miniaturized integrated power supplies.

  7. Laser spectroscopy used in nuclear physics; La spectroscopie laser appliquee a la physique nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Le Blanc, F

    2001-04-05

    The study of nuclear shapes is a basic topic since it constitutes an excellent ground for testing and validating nuclear models. Measurements of the electron quadrupolar moment, of the nuclear charge radius and of the magnetic dipolar moment shed light on the nuclear deformation. Laser spectroscopy is a specific tool for such measurements, it is based on the interaction of the nucleus with the surrounding electron cloud (hyperfine structure), it is then an external approach of the shape of the nucleus whereas the classical nuclear spectroscopy ({alpha}, {beta} or {gamma}) gives information on the deformation from the inside of the nucleus. The author describes 2 techniques of laser spectroscopy: the colinear spectroscopy directly applied to a beam issued from an isotope separator and the resonant ionization spectroscopy linked with atom desorption that allows the study of particular nuclei. In order to illustrate both methods some effective measurements are presented: - the colinear spectroscopy has allowed the achievement of the complete description of the isomeric state (T = 31 years) of hafnium-178; - The experiment Complis has revealed an unexpected even-odd zigzag effect on very neutron-deficient platinum isotopes; and - the comparison of 2 isotopes of gold and platinum with their isomers has shown that the inversion of 2 levels of neutron, that was found out by nuclear spectroscopy, is in fact a consequence of a change in the nuclear shape. (A.C.)

  8. High spatial resolution measurements of NO2 applying Topographic Target Light scattering-Differential Optical Absorption Spectroscopy (ToTaL-DOAS)

    OpenAIRE

    Wagner, T; U. Platt; Frins, E.

    2008-01-01

    International audience Tomographic Target Light scattering ? Differential Optical Absorption Spectroscopy (ToTaL-DOAS), also called Target-DOAS, is a novel experimental procedure to retrieve trace gas concentrations present in the low atmosphere. Scattered sunlight (partially or totally) reflected from natural or artificial targets of similar albedo located at different distances is analyzed to retrieve the concentration of different trace gases like NO2, SO2 and others. We report high spa...

  9. High spatial resolution measurements of NO2 applying Topographic Target Light scattering-Differential Optical Absorption Spectroscopy (ToTaL-DOAS)

    OpenAIRE

    Frins, E.; U. Platt; Wagner, T

    2008-01-01

    Topographic Target Light scattering – Differential Optical Absorption Spectroscopy (ToTaL-DOAS), also called Target-DOAS, is a novel experimental procedure to retrieve trace gas concentrations present in the low atmosphere. Scattered sunlight (diffuse or specular) reflected from natural or artificial targets located at different distances are analyzed to retrieve the spatial distribution of the concentration of different trace gases like NO2, SO2 and others. We report high s...

  10. Proton response of CEPA4: A novel LaBr3(Ce)–LaCl3(Ce) phoswich array for high-energy gamma and proton spectroscopy

    International Nuclear Information System (INIS)

    A new phoswich array, for the detection of high-energy protons and gamma rays from nuclear reactions, has been built. This new detector consists of four individual closely packed scintillator detectors, each of them made of 4 cm of LaBr3(Ce) and 6 cm of LaCl3(Ce) in phoswich configuration (optically coupled and with a common readout). In this paper we report on the results of a beam test performed at the Bronowice Cyclotron Centre (CCB) in Krakow, showing the response of this versatile instrument to high energy protons (70–230 MeV). Furthermore, for the first time we prove that we can reconstruct the original energy of fast protons (E>200MeV) which pass through the total length of the crystal while still retaining a good energy resolution

  11. Investigation of the beta strength function at high energy: Gamma-ray spectroscopy of the decay of 5.3-s 84As to 84Se

    International Nuclear Information System (INIS)

    We have investigated the beta strength function up to approximately 8.6 MeV for the system 84As(β-)84Se. We find that it is not possible to satisfactorily describe Ssub(β) by a statistical model. From the 84As decay scheme we deduce an experimental beta strength function. Additional information on the beta transition intensity is obtained from the gross coincidence spectra of individual gamma rays. In total these data suggest that the experimental beta strength function above 6.8 MeV is significantly lower than that calculated using a statistical model. Features in the gross coincidence spectra also suggest that a significant bump appears in the experimental beta strength function at approximately 6.5 MeV. (orig.)

  12. Design of a large-area CsI(Tl) photo-diode array for explosives detection by neutron-activation gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    A design for a large area, position-sensitive gamma-ray spectrometer for use in imaging explosive materials is described. The design has been optimised for use in the energy range from 2 to 12 MeV. At 5 MeV, the spectral resolution of each CsI(Tl)-photodiode pixel is better than 3% FWHM. The multi-element detector system, when used in conjunction with a coded-aperture mask, is able to provide a 'multi-colour' image of the scene when illuminated by a neutron source. The feasibility of using such a system to identify the unique elemental composition and location of the explosive materials is discussed

  13. Formation of fine palladium particles from palladium sulfate aqueous solution by gamma-ray irradiation as observed by electronic absorption spectroscopy and dynamic light scattering

    International Nuclear Information System (INIS)

    To find a way of probing the coagulation of metal particles formed by the irradiation of metallic ion solution without surfactant, palladium sulfate aqueous solution was irradiated with gamma rays (11.2kGy/h, 10kGy) and turbidity change of the solution after irradiation was followed by optical density at 700nm using a UV-visible spectrophotometer. The particle diameter distribution was monitored by dynamic light scattering. The results indicate that the turbidity decreased monotonously, and that there are major peaks in the distributions, one with diameters in the 400-800nm region and the other with diameters in the 1500-2500nm. The density of the particles seems to be smaller than that of bulk palladium metal. Similar experiments were carried out on palladium-silver sulfate solution. (author)

  14. Optogalvanic spectroscopy

    International Nuclear Information System (INIS)

    Laser induced optogalvanic spectroscopy in a hollow cathode-produced plasma has been used to resolve the isotopic structure of some absorption lines in uranium. We have shown that the optogalvanic signal associated with any isotope can be related to the concentration of that isotope in a multi-isotopic sample. From the results we have obtained, optogalvanic spectroscopy of sputtered samples appears to be an interesting approach to the isotopic analysis of both natural and enriched uranium and could easily be applied to the analysis of other fissile elements, such as the plutonium isotopes

  15. Nuclear gamma resonance absorption (Moessbauer) spectroscopy as an archaeometric technique to assess chemical states of iron in a Tupiguarani ceramic artifact from Corinto, Minas Gerais, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Floresta, D.L.; Ardisson, J.D., E-mail: denise.floresta@ifmg.edu.br, E-mail: jdr@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Fagundes, M.; Fabris, J.D., E-mail: marcelo.fagundes@ufvjm.edu.br, E-mail: jdfabris@ufmg.edu.br [Universidade Federal dos Vales do Jequitinhonha e Mucuri (LAEP/UFVJM), Diamantina, MG (Brazil). Lab. de Arqueologia e Estudos da Paisagem

    2013-07-01

    Archaeological ceramics of Tupiguarani Tradition are found in many parts throughout the Brazilian territory and have many similarities. Fragments of Tupiguarani pottery found in the archaeological site known as Beltrao, in the municipality of Corinto, state of Minas Gerais, were identified and collected by researchers of the LAEP/UFVJM, in Diamantina, also in Minas Gerais. A selected fragment of about 15 mm-thick, with a color gradation across the ceramic wall ranging from red, on one side, grayish in the middle and orange on the opposite side, was transversely cut and a series of subsamples of powdered materials were collected from different depths across the wall, in layer segments of ∼3 mm, from the orange side. These powdered subsamples were analyzed with X-ray fluorescence and diffraction spectroscopy and {sup 57}Fe Moessbauer spectroscopy at room temperature (298 K) and at 80 K. According to the XRF results, the elementary composition does not clearly vary with the depth in the sample. The powder XRD analysis revealed the occurrence mainly of quartz and muscovite. Results of {sup 57}Fe Moessbauer spectroscopy reveal that hematite is the magnetically ordered phase. An Fe{sup 2+} component appears for the grayish subsample. According to these results, the red subsample seems to be the external part of the pottery, representing the side that had direct contact with fire used to burn the precursor clay in air for this primitive ceramics preparation. The grayish middle layer is probably due to burning clay mixed with some ashes containing residual carbon, under milder temperature than on the external . (author)

  16. Low-Resolution Spectroscopy of Gamma-ray Burst Optical Afterglows: Biases in the Swift Sample and Characterization of the Absorbers

    CERN Document Server

    Fynbo, J P U; Prochaska, J X; Malesani, D; Ledoux, C; Postigo, A de Ugarte; Nardini, M; Vreeswijk, P M; Hjorth, J; Sollerman, J; Chen, H -W; Thoene, C C; Bjoernsson, G; Bloom, J S; Castro-Tirado, A J; Christensen, L; De Cia, A; Gorosabel, J U; Jaunsen, A; Jensen, B L; Levan, A; Maund, J; Masetti, N; Milvang-Jensen, B; Palazzi, E; Perley, D A; Pian, E; Rol, E; Schady, P; Starling, R; Tanvir, N; Watson, D J; Wiersema, K; Xu, D; Augusteijn, T; Grundahl, F; Telting, J; Quirion, P -O

    2009-01-01

    (Abridged). We present a sample of 77 optical afterglows (OAs) of Swift detected GRBs for which spectroscopic follow-up observations have been secured. We provide linelists and equivalent widths for all detected lines redward of Ly-alpha. We discuss to what extent the current sample of Swift bursts with OA spectroscopy is a biased subsample of all Swift detected GRBs. For that purpose we define an X-ray selected sample of Swift bursts with optimal conditions for ground-based follow up from the period March 2005 to September 2008; 146 bursts fulfill our sample criteria. We derive the redshift distribution for this sample and conclude that less than 19% of Swift bursts are at z>7. We compare the high energy properties for three sub-samples of bursts in the sample: i) bursts with redshifts measured from OA spectroscopy, ii) bursts with detected OA, but no OA-based redshift, and iii) bursts with no detection of the OA. The bursts in group i) have significantly less excess X-ray absorption than bursts in the other...

  17. A digital multi-channel spectroscopy system with 100 MHz flash ADC module for the GENIUS-TF and GENIUS projects

    OpenAIRE

    Kihm, T.; Bobrakov, V. F.; Klapdor-Kleingrothaus, H. V.

    2003-01-01

    In this paper we will present the first results of applying a digital processing technology in low-level gamma spectroscopy with HPGE detectors. An experimental gamma spectrometer using Flash ADC module is built and tested. The test system is now under development and shows major advantages over the traditional analog technologies. It will be installed for the GENIUS-TF and GENIUS projects in Gran-Sasso in early 2003.

  18. A digital multi-channel spectroscopy system with 100 MHz flash ADC module for the GENIUS-TF and GENIUS projects

    International Nuclear Information System (INIS)

    In this paper we present the first results of applying a digital processing technology in low-level gamma spectroscopy with HPGE detectors. An experimental gamma spectrometer using Flash ADC module is built and tested. The test system is now under development and shows major advantages over the traditional analog technologies. It will be installed for the GENIUS-TF and GENIUS projects in Gran-Sasso in early 2003

  19. Soft X-ray Transmission Spectroscopy of Warm/Hot Intergalactic Medium: Mock Observation of Gamma-Ray Burst X-ray Afterglow

    CERN Document Server

    Kawahara, H; Sasaki, S; Suto, Y; Kawai, N; Mitsuda, K; Ohashi, T; Yamasaki, N; Kawahara, Hajime; Yoshikawa, Kohji; Sasaki, Shin; Suto, Yasushi; Kawai, Nobuyuki; Mitsuda, Kazuhisa; Ohashi, Takaya; Yamasaki, Noriko

    2005-01-01

    We discuss the detectability of Warm/Hot Intergalactic medium (WHIM) via the absorption lines toward bright gamma-ray burst (GRB) afterglows with future X-ray satellite missions like XEUS. We create mock absorption spectra for bright GRB afterglows ($\\sim 40$ per year over the entire sky) using a light-cone output of a cosmological hydrodynamic simulation. We assume that WHIM is under collisional and photo-ionization equilibrium. If we adopt the constant metallicity of $Z=0.1Z_\\odot$, approximately one O{\\sc vii} absorption line system with $>3\\sigma$ will be detected on average along a random line-of-sight up to $z=0.3$ if XEUS starts observing within a couple of hours after the GRB alert. However the above number is very sensitive to the adopted, and currently unknown, metallicity of the WHIM. We also discuss a feasibility of a follow-up observation for the emission line counterpart with a small dedicated X-ray mission like DIOS (Diffuse Intergalactic Oxygen Surveyor) and reliability of the estimate of the ...

  20. Spectroscopy of $^{19}$Ne for the thermonuclear $^{15}$O($\\alpha,\\gamma$)$^{19}$Ne and $^{18}$F($p,\\alpha$)$^{15}$O reaction rates

    CERN Document Server

    Parikh, A; de Séréville, N; Wimmer, K; Faestermann, T; Hertenberger, R; Seiler, D; Wirth, H -F; Adsley, P; Fulton, B R; Hammache, F; Kiener, J; Stefan, I

    2015-01-01

    Uncertainties in the thermonuclear rates of the $^{15}$O($\\alpha,\\gamma$)$^{19}$Ne and $^{18}$F($p,\\alpha$)$^{15}$O reactions affect model predictions of light curves from type I X-ray bursts and the amount of the observable radioisotope $^{18}$F produced in classical novae, respectively. To address these uncertainties, we have studied the nuclear structure of $^{19}$Ne over $E_{x} = 4.0 - 5.1$ MeV and $6.1 - 7.3$ MeV using the $^{19}$F($^{3}$He,t)$^{19}$Ne reaction. We find the $J^{\\pi}$ values of the 4.14 and 4.20 MeV levels to be consistent with $9/2^{-}$ and $7/2^{-}$ respectively, in contrast to previous assumptions. We confirm the recently observed triplet of states around 6.4 MeV, and find evidence that the state at 6.29 MeV, just below the proton threshold, is either broad or a doublet. Our data also suggest that predicted but yet unobserved levels may exist near the 6.86 MeV state. Higher resolution experiments are urgently needed to further clarify the structure of $^{19}$Ne around the proton thresh...

  1. Probing the wind-wind collision in Gamma Velorum with high-resolution Chandra X-ray spectroscopy: evidence for sudden radiative braking and non-equilibrium ionization

    CERN Document Server

    Henley, D B; Pittard, J M

    2004-01-01

    We present a new analysis of an archived Chandra HETGS X-ray spectrum of the WR+O colliding wind binary Gamma Velorum. The spectrum is dominated by emission lines from astrophysically abundant elements: Ne, Mg, Si, S and Fe. From a combination of broad-band spectral analysis and an analysis of line flux ratios we infer a wide range of temperatures in the X-ray emitting plasma (~4-40 MK). As in the previously published analysis, we find the X-ray emission lines are essentially unshifted, with a mean FWHM of 1240 +/- 30 km/s. Calculations of line profiles based on hydrodynamical simulations of the wind-wind collision predict lines that are blueshifted by a few hundred km/s. The lack of any observed shift in the lines may be evidence of a large shock-cone opening half-angle (> 85 degrees), and we suggest this may be evidence of sudden radiative braking. From the R and G ratios measured from He-like forbidden-intercombination-resonance triplets we find evidence that the Mg XI emission originates from hotter gas c...

  2. Cu(I), Ag(I), Cd(II), and Pb(II) binding to biomolecules studied by perturbed angular correlation of $\\gamma$-rays (PAC) spectroscopy

    CERN Multimedia

    Metal ions display diverse functions in biological systems and are essential components in both protein and nucleic acid structure and function, and in control of biochemical reaction paths and signalling. Similarly, metal ions may be used to control structure and function of synthetic biomolecules, and thus be a tool in the design of molecules with a desired function. In this project we address a variety of questions concerning both the function of metal ions in natural systems, in synthetic biomolecules, and the toxic effect of some metal ions. All projects involve other experimental techniques such as NMR, EXAFS, UV-Vis, fluorescence, and CD spectroscopies providing complementary data, as well as interpretation of the experimental data by quantum mechanical calculations of spectroscopic properties. The isotopes to be employed in the proposal are the following: $^{111m}$Cd, $^{111}$Ag, $^{199}$mHg, $^{204m}$Pb, $^{61}$Cu, $^{68m}$Cu

  3. Progress of infrared spectroscopy and near-infrared spectroscopy applied to food analysis%红外及近红外光谱技术在食品分析检验中的应用进展

    Institute of Scientific and Technical Information of China (English)

    刘嘉俊

    2009-01-01

    红外及近红外波谱技术,是利用物质对红外光区的电磁辐射的选择性吸收来进行结构分析及定性和定量分析,具有快速,方便,样品用量少,不损坏样品等优点.%Infrared spectroscopy and near-infraredspectroscopy has been widely used in the internal quality inspection of food products. The principle is to use ele-ments in the sample contained near-infrared spectral re-gions of the strongest absorption of different wavelengths,and the absorption of organic ingredients and the strength of a linear relationship between the quantitative and qualitative analysis. The advantage is fast, convenient and less sample consumption, non-destructive.

  4. Exploring the "Island of Inversion" by in-beam gamma-ray spectroscopy of the neutron-rich sodium isotopes 31,32,33Na

    CERN Document Server

    Doornenbal, P; Kobayashi, N; Aoi, N; Takeuchi, S; Li, K; Takeshita, E; Togano, Y; Wang, H; Deguchi, S; Kawada, Y; Kondo, Y; Motobayashi, T; Nakamura, T; Satou, Y; Tanaka, K N; Sakurai, H

    2010-01-01

    The structure of the neutron rich sodium isotopes 31,32,33Na was investigated by means of in-beam gammaray spectroscopy following one-neutron knockout and inelastic scattering of radioactive beams provided by the RIKEN Radioactive Ion Beam Factory. The secondary beams were selected and separated by the fragment separator BigRIPS and incident at ~240 meV/u on a natural carbon (secondary) target, which was surrounded by the DALI2 array to detect coincident de-excitation gammarays. Scattered particles were identified by the spectrometer ZeroDegree. In 31Na, a new decay gammaray was observed in coincidence with the known (5/2+)-> 3/2(+) transition, while for 32,33Na excited states are reported for the first time. From a comparison to state-of-the-art shell model calculations it is concluded that the newly observed excited state in 31Na belongs to a rotational band formed by a 2p2h intruder configuration within the "Island of Inversion".

  5. Investigation of (235)U, (226)Ra, (232)Th, (40)K, (137)Cs, and heavy metal concentrations in Anzali international wetland using high-resolution gamma-ray spectrometry and atomic absorption spectroscopy.

    Science.gov (United States)

    Zare, Mohammad Reza; Kamali, Mahdi; Fallahi Kapourchali, Maryam; Bagheri, Hashem; Khoram Bagheri, Mahdi; Abedini, Ali; Pakzad, Hamid Reza

    2016-02-01

    Measurements of natural radioactivity levels and heavy metals in sediment and soil samples of the Anzali international wetland were carried out by two HPGe-gamma ray spectrometry and atomic absorption spectroscopy techniques. The concentrations of (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs in sediment samples ranged between 1.05 ± 0.51-5.81 ± 0.61, 18.06 ± 0.63-33.36 ± .0.34, 17.57 ± 0.38-45.84 ± 6.23, 371.88 ± 6.36-652.28 ± 11.60, and 0.43 ± 0.06-63.35 ± 0.94 Bq/kg, while in the soil samples they vary between 2.36-5.97, 22.71-38.37, 29.27-42.89, 472.66-533, and 1.05-9.60 Bq/kg for (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. Present results are compared with the available literature data and also with the world average values. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. Heavy metal concentrations were found to decrease in order as Fe > Mn > Sr > Zn > Cu > Cr > Ni > Pb > Co > Cd. These measurements will serve as background reference levels for the Anzali wetland. PMID:26490904

  6. Ultrasonography X gamma radiography

    International Nuclear Information System (INIS)

    The accumulated experience in the last ten years of substitution to essays by gamma radiography to essay by ultrasonography, starting of the systematic comparison and tabulation of the results obtained by both essays applied in welding joints, in field, in steel pipelines of the SABESP. (V.R.B.)

  7. A NEARBY GAMMA-RAY BURST HOST PROTOTYPE FOR z ∼ 7 LYMAN-BREAK GALAXIES: SPITZER-IRS AND X-SHOOTER SPECTROSCOPY OF THE HOST GALAXY OF GRB 031203

    International Nuclear Information System (INIS)

    Gamma-ray burst (GRB) host galaxies have been studied extensively in optical photometry and spectroscopy. Here we present the first mid-infrared spectrum of a GRB host, HG 031203. It is one of the nearest GRB hosts at z = 0.1055, allowing both low- and high-resolution spectroscopy with the Spitzer Infrared Spectrograph (IRS). Medium-resolution UV to K-band spectroscopy with the X-shooter spectrograph on the Very Large Telescope is also presented, along with Spitzer IRAC and MIPS photometry, as well as radio and submillimeter observations. These data allow us to construct a UV to radio spectral energy distribution with almost complete spectroscopic coverage from 0.3 to 35 μm of a GRB host galaxy for the first time, potentially valuable as a template for future model comparisons. The IRS spectra show strong, high-ionization fine structure line emission indicative of a hard radiation field in the galaxy—in particular the [S IV]/[S III] and [Ne III]/[Ne II] ratios—suggestive of strong ongoing star formation and a very young stellar population. The absence of any polycyclic aromatic hydrocarbon emission supports these conclusions, as does the probable hot peak dust temperature, making HG 031203 similar to the prototypical blue compact dwarf galaxy (BCD), II Zw 40. The selection of HG 031203 via the presence of a GRB suggests that it might be a useful analog of very young star-forming galaxies in the early universe, and hints that local BCDs may be used as more reliable analogs of star formation in the early universe than typical local starbursts. We look at the current debate on the ages of the dominant stellar populations in z ∼ 7 and z ∼ 8 galaxies in this context. The nebular line emission is so strong in HG 031203 that at z ∼ 7, it can reproduce the spectral energy distributions of z-band dropout galaxies with elevated IRAC 3.6 and 4.5 μm fluxes without the need to invoke a 4000 Å break. Indeed, photometry of HG 031203 shows elevation of the broadband V

  8. Photometry and spectroscopy of GRB 060526: a detailed study of the afterglow and host galaxy of a z = 3.2 gamma-ray burst

    Science.gov (United States)

    Thöne, C. C.; Kann, D. A.; Jóhannesson, G.; Selj, J. H.; Jaunsen, A. O.; Fynbo, J. P. U.; Akerlof, C. W.; Baliyan, K. S.; Bartolini, C.; Bikmaev, I. F.; Bloom, J. S.; Burenin, R. A.; Cobb, B. E.; Covino, S.; Curran, P. A.; Dahle, H.; Ferrero, A.; Foley, S.; French, J.; Fruchter, A. S.; Ganesh, S.; Graham, J. F.; Greco, G.; Guarnieri, A.; Hanlon, L.; Hjorth, J.; Ibrahimov, M.; Israel, G. L.; Jakobsson, P.; Jelínek, M.; Jensen, B. L.; Jørgensen, U. G.; Khamitov, I. M.; Koch, T. S.; Levan, A. J.; Malesani, D.; Masetti, N.; Meehan, S.; Melady, G.; Nanni, D.; Näränen, J.; Pakstiene, E.; Pavlinsky, M. N.; Perley, D. A.; Piccioni, A.; Pizzichini, G.; Pozanenko, A.; Roming, P. W. A.; Rujopakarn, W.; Rumyantsev, V.; Rykoff, E. S.; Sharapov, D.; Starr, D.; Sunyaev, R. A.; Swan, H.; Tanvir, N. R.; Terra, F.; de Ugarte Postigo, A.; Vreeswijk, P. M.; Wilson, A. C.; Yost, S. A.; Yuan, F.

    2010-11-01

    Aims: With this paper we want to investigate the highly variable afterglow light curve and environment of gamma-ray burst (GRB) 060526 at z = 3.221. Methods: We present one of the largest photometric datasets ever obtained for a GRB afterglow, consisting of multi-color photometric data from the ultraviolet to the near infrared. The data set contains 412 data points in total to which we add additional data from the literature. Furthermore, we present low-resolution high signal-to-noise spectra of the afterglow. The afterglow light curve is modeled with both an analytical model using broken power law fits and with a broad-band numerical model which includes energy injections. The absorption lines detected in the spectra are used to derive column densities using a multi-ion single-component curve-of-growth analysis from which we derive the metallicity of the host of GRB 060526. Results: The temporal behaviour of the afterglow follows a double broken power law with breaks at t = 0.090 ± 0.005 and t = 2.401 ± 0.061 days. It shows deviations from the smooth set of power laws that can be modeled by additional energy injections from the central engine, although some significant microvariability remains. The broadband spectral-energy distribution of the afterglow shows no significant extinction along the line of sight. The metallicity derived from S ii and Fe ii of [S/H] = -0.57 ± 0.25 and [Fe/H] = -1.09 ± 0.24 is relatively high for a galaxy at that redshift but comparable to the metallicity of other GRB hosts at similar redshifts. At the position of the afterglow, no host is detected to F775W(AB) = 28.5 mag with the HST, implying an absolute magnitude of the host M(1500 Å) > -18.3 mag which is fainter than most long-duration hosts, although the GRB may be associated with a faint galaxy at a distance of 11 kpc. Based in part on observations obtained with the European Southern Observatory's Very Large Telescope under proposals 077.D-0661 (PI: Vreeswijk) and 177.A-0591

  9. Study of natural and man-made radioactivity levels in coastal sediment collected from the Kelani river outfall by gamma spectroscopy

    International Nuclear Information System (INIS)

    In Sri Lanka, there is hardly any threat of nuclear contamination of the local environment from within the country at present. However this environment could be exposed to nuclear contamination via the disposal of nuclear waste in the Indian Ocean or via any nuclear accident of civil or military nature in the world. From a radiation protection point of view; it is valuable as a reference term to determine the levels of artificial radioactivity from such activities. As such, establishment of baseline data on environmental radioactivity levels is necessary. Therefore it is appropriate to identify radionuclides present in the environment and to study the spatial and temporal behaviour of the concentration levels of radionuclides which are of major concern. In the present study an estuary was chosen as the study area and a detailed study of the specific activities of U sup 238, Th sup 232 and K sup 40 in this sediment was performed. Forty-three sediment samples were collected from the near-shore region of Kelani river estuary at Colombo city in 1997 and analysed by gamma-spectrometry employing high resolution HPGE detector system. The specific activities at secular equilibrium conditions ranged from 29-60 B q per kg for U sup 238, 53-117 Bq per kg for Th sup 232 and 289-550 Bq per kg for K sup 40 on a dry weight basis. The values for K sup 40 and U sup 238 obtained in the present study are comparable with the values reported by other researchers. However the values obtained for Th sup 232 in the present study appear to be greater than the thorium content commonly found in stream sediments. The effect of heavy rainfall on the radionuclide concentrations was investigated and a variability was not found for the nuclides studied. A correlation coefficient of 0.49 was determined at 99 percent significance level for Th sup 232 and U sup 238 concentration data, indicating poor correlation. The activity ratio of Th sup 232/ U sup 238 was greater than unity for almost all

  10. High spatial resolution measurements of NO2 applying Topographic Target Light scattering-Differential Optical Absorption Spectroscopy (ToTaL-DOAS

    Directory of Open Access Journals (Sweden)

    T. Wagner

    2008-06-01

    Full Text Available Tomographic Target Light scattering – Differential Optical Absorption Spectroscopy (ToTaL-DOAS, also called Target-DOAS, is a novel experimental procedure to retrieve trace gas concentrations present in the low atmosphere. Scattered sunlight (partially or totally reflected from natural or artificial targets of similar albedo located at different distances is analyzed to retrieve the concentration of different trace gases like NO2, SO2 and others. We report high spatial resolution measurements of NO2 mixing ratios in the city of Montevideo (Uruguay observing three buildings as targets with a Mini-DOAS instrument. Our instrument was 146 m apart from the first building, 196 m from the second and 286 m from the third one. All three buildings are located along a main Avenue. We obtain temporal variation of NO2 mixing ratios between 30 ppb and 65 ppb (±2 ppb. Our measurements demonstrate that ToTaL-DOAS measurements can be made over very short distances. In polluted air masses, the retrieved absorption signal was found to be strong enough to allow measurements over distances in the range of several ten meters, and achieve a spatial resolution of 50 m approximately.

  11. New analytical methods for materials characterization using the techniques of nuclear activation reactions induced by thermal neutrons and accelerated ion beams, coupled to gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    data from nuclear activation reactions. In the theoretical part of the thesis (Chapter 2) an explanation for the 'critical' phenomena discussed in the CPAA literature was advanced. In Chapters 3-4, new analytical formulae were derived, based on new nuclear parameters (z0, z), which are similar to the known (k0, k) parameters for the NAA field. A new, absolute standardization method, without any reference standard was also described. Chapter 5 presents new, original applications for determining the energy of the accelerated ion beams and thickness of thin materials, while the Chapter 6 describes two practical methods for optimizing the experiments: the Unitary (CPAA-NAA) analytical method based on the new parameters (z0, z), and the Optographic Method based on the specific evolution of each radionuclide. A new concept of the software for processing the experimental data from nuclear activation was developed for CPAA and NAA, and a database of the specific nuclear data was constructed (Chapter 7) by using the 'Fox-Pro' operating system. The experimental CPAA setup (Chapter 8) was a newly constructed reaction vacuum chamber based on the author's design, which allowed an accurate control of the electrical charge transferred to the target and reproducibility of irradiation; the analysis of the gamma-ray spectra from both types of irradiation was carried out by a spectrometer with a high resolution HPGe detector. In conclusion (Chapter 9) this thesis is significant for the field of analysis by nuclear activation (CPAA, and NAA) due to the original contributions to the theoretical, methodological, experimental and specific software and calculation methods. (author)

  12. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes

    Energy Technology Data Exchange (ETDEWEB)

    Wiesinger, R. [Institute of Science and Technology in Art, Academy of Fine Arts, 1010 Vienna (Austria); Schade, U. [Helmholtz-Zentrum für Materialien und Energy GmbH, Elektronenspeicherring BESSY II, 12489 Berlin (Germany); Kleber, Ch. [Centre for Electrochemical Surface Technology, 2700 Wiener Neustadt (Austria); Schreiner, M. [Institute of Science and Technology in Art, Academy of Fine Arts, 1010 Vienna (Austria); Institute for Chemical Technologies and Analytics, Vienna University of Technology, 1060 Vienna (Austria)

    2014-06-15

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  13. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes

    Science.gov (United States)

    Wiesinger, R.; Schade, U.; Kleber, Ch.; Schreiner, M.

    2014-06-01

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  14. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes

    International Nuclear Information System (INIS)

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations

  15. Measuring the Luminosity of a gamma gamma Collider with gamma gamma -> l+ l- gamma Events

    OpenAIRE

    Makarenko, V.; Moenig, K.; Shishkina, T.

    2003-01-01

    The process gamma gamma -> l+ l- is highly suppressed when the total angular momentum of the two colliding photons is zero so that it cannot be used for luminosity determination. This configuration, however is needed for Higgs production at a photon collider. It will be shown that the process gamma gamma -> l+ l- gamma can be used in this case to measure the luminosity of a collider with a precision that is good enough not to limit the error on the partial decay width Gamma(H -> gamma gamma).

  16. Original implementation of Electrochemical Impedance Spectroscopy (EIS) in symmetric cells: Evaluation of post-mortem protocols applied to characterize electrode materials for Li-ion batteries

    Science.gov (United States)

    Gordon, Isabel Jiménez; Genies, Sylvie; Si Larbi, Gregory; Boulineau, Adrien; Daniel, Lise; Alias, Mélanie

    2016-03-01

    Understanding ageing mechanisms of Li-ion batteries is essential for further optimizations. To determine performance loss causes, post-mortem analyses are commonly applied. For each type of post-mortem test, different sample preparation protocols are adopted. However, reports on the reliability of these protocols are rare. Herein, Li-ion pouch cells with LiNi1/3Mn1/3Co1/3O2 - polyvinylidene fluoride positive electrode, graphite-carboxymethyl cellulose-styrene rubber negative electrode and LiPF6 - carbonate solvents mixture electrolyte, are opened and electrodes are recovered following a specified protocol. Negative and positive symmetric cells are assembled and their impedances are recorded. A signal analysis is applied to reconstruct the Li-ion pouch cell impedance from the symmetric cells, then comparison against the pouch cell true impedance allows the evaluation of the sample preparation protocols. The results are endorsed by Transmission Electronic Microscopy (TEM) and Gas Chromatography - Mass Spectrometry (GC-MS) analyses. Carbonate solvents used to remove the salt impacts slightly the surface properties of both electrodes. Drying electrodes under vacuum at 25 °C produces an impedance increase, particularly very marked for the positive electrode. Drying at 50 °C under vacuum or/and exposition to the anhydrous room atmosphere is very detrimental.

  17. Two-dimensional low resolution Raman spectroscopy applied to fast discrimination of microorganisms that cause pharyngitis: A whole-organism fingerprinting approach

    Science.gov (United States)

    Mello, Cesar; Severi, Eza; Coelho, Lucinda; Marangoni, Antônio; Dezuane, Christiane; Ricci, Emiliane; Ribeiro, Diórginis; Poppi, Ronei Jesus

    2008-07-01

    The discrimination of the bacteria that cause pharyngitis through classical-microbiological methods is very efficient in the great majority of the cases. However, the high cost of chemicals and the time spent for such identifications, about four days, could generate serious consequences for the patients. Thus, the search for low cost spectroscopic methods which would allow a fast and reagentless discrimination of these microorganisms is extremely relevant. In this work, the main microorganisms that cause pharyngitis: S. aureus, S. pyogenes and Neisseria gonorrhoeae were studied. For each of the microorganisms 60 different dispersions were prepared using physiological solution as solvent and its Raman spectra were recorded. The 1D spectra obtained were similar, making it very difficult to differentiate the microorganisms. However, applying the 2D correlation method, it was possible to identify the microorganisms evaluated using the synchronous spectrum as "whole-organism fingerprinting" in a reduced time interval (˜10 h).

  18. An application of the coincidence Doppler spectroscopy for substances of chemical interest: phthalocyanine and acetylacetonate complexes

    CERN Document Server

    Ito, Y

    2000-01-01

    Coincidence Doppler spectroscopy, which is particularly powerful when one is concerned with high momentum components of positron annihilation gamma-rays, has been applied to two different kinds of organo-metallic ligands: metal phthalocyanines and metal acetylacetonates. The energy (momentum) profiles of the annihilation gamma-rays were the same for metal phthalocyanines indicating that positron and/or positronium are not interacting with the metal ions. However, the profiles for the metal acetylacetonates evidently showed a dependence on the kind of metal ions. Discussion is made on the features of positron interaction which are different for phthalocyanines and acetylacetonates.

  19. Local environments and lithium adsorption on the iron oxyhydroxides lepidocrocite (gamma-FeOOH) and goethite (alpha-FeOOH): A 2H-2 and 7Li solid-state MAS NMR study

    DEFF Research Database (Denmark)

    Nielsen, Ulla Gro; Grey, Clare P.; Paik, Jonkim

    2008-01-01

    2H and 7LiMAS NMR spectroscopy techniques were applied to study the local surface and bulk environments of iron oxyhydroxide lepiclocrocite (gamma-FeOOH). 2H variable-temperature (VT) MAS NMR experiments were performed, showing the presence of short-range, strong antiferromagnetic correlations, e...

  20. Laser induced breakdown spectroscopy (LIBS) applied to stratigrafic elemental analysis and optical coherence tomography (OCT) to damage determination of cultural heritage Brazilian coins

    Science.gov (United States)

    M. Amaral, Marcello; Raele, Marcus P.; Z. de Freitas, Anderson; Zahn, Guilherme S.; Samad, Ricardo E.; D. Vieira, Nilson, Jr.; G. Tarelho, Luiz V.

    2009-07-01

    This work presents a compositional characterization of 1939's Thousand "Réis" and 1945's One "Cruzeiro" Brazilian coins, forged on aluminum bronze alloy. The coins were irradiated by a Q-switched Nd:YAG laser with 4 ns pulse width and energy of 25mJ emitting at 1064nm reaching 3.1010Wcm-2 (assured condition for stoichiometric ablation), forming a plasma in a small fraction of the coin. Plasma emission was collected by an optical fiber system connected to an Echelle spectrometer. The capability of LIBS to remove small fraction of material was exploited and the coins were analyzed ablating layer by layer from patina to the bulk. The experimental conditions to assure reproductivity were determined by evaluation of three plasma paramethers: ionization temperature using Saha-Boltzmann plot, excitation temperature using Boltzmann plot, plasma density using Saha-Boltzmann plot and Stark broadening. The Calibration-Free LIBS technique was applied to both coins and the analytical determination of elemental composition was employed. In order to confirm the Edict Law elemental composition the results were corroborated by Neutron Activation Analysis (NAA). In both cases the results determined by CF-LIBS agreed to with the Edict Law and NAA determination. Besides the major components for the bronze alloy some other impurities were observed. Finally, in order to determine the coin damage made by the laser, the OCT (Optical Coherence Tomography) technique was used. After tree pulses of laser 54μg of coin material were removed reaching 120μm in depth.

  1. General Remarks about mossbauer spectroscopy

    International Nuclear Information System (INIS)

    More than forty years have passed since the discovery of Mossbauer effect; one of the most brilliant findings in modern physics. This effect proved itself to be the powerful tool in almost all disciplines of the natural sciences and technology. Its unique feature is that it gives the possibility to get the results which cannot be obtained by any other physical methods. Mossbauer effect has been used as a key to unlock some basic physical, chemical and biological phenomena, as a guide for finding the new ways of solving applied scientific and technical problems of electronics, metallurgy, civil engineering, and even fine arts and archaeology. Very few scientific techniques can claim entry into as many countries as Mossbauer spectroscopy. Due to its wide application in an education and research processes the community of Mossbauer spectroscopists extends to almost 100 different countries. Laboratory equipment necessary for conducting gamma resonance spectroscopy, do not require large investments, premises, personnel. The spectrometer is rather small in size and could be installed on the ordinary laboratory table. That is why Mossbauer effect is widely used at numerous Universities all over the world as an universal instrument for tuition and research

  2. Physico-chemical behavior of ultra high molecular weight polyethylene gamma-irradiated

    International Nuclear Information System (INIS)

    Ultra high molecular weight polyethylene (UHMWPE) has been used in several applications, due to its excellent engineering properties. Since 70' that UHMWPE is applied in medical devices specially in orthopedic implants. The use of gamma irradiation has become the preferred method for sterilizing medical products. It is well known that the exposure to gamma rays introduces structural changes that may alter the polymer performance. In the present work, a commercial grade UHMWPE was exposed to gamma radiation at room temperature in the air. The effect of the irradiation on the physico-chemical behavior of a commercial UHMWPE was investigated by gel determination, infrared spectroscopy analysis and thermal analysis (TGA and DSC). The experimental data show changes in the physico-chemical behavior of UHMWPE. The results are presented and discussed. (author)

  3. Study of the N=28 shell closure by one neutron transfer reaction: astrophysical application and {beta}-{gamma} spectroscopy of neutron rich nuclei around N=32/34 and N=40; Etude de la fermeture de couche N=28 autour du noyau {sub 18}{sup 46}Ar{sub 28} par reaction de transfert d'un neutron: application a l'astrophysique et Spectroscopie {beta}-{gamma} de noyaux riches en neutrons de N=32/34 et N=40

    Energy Technology Data Exchange (ETDEWEB)

    Gaudefroy, L

    2005-09-15

    The study of the N=28 shell closure has been presented as well as its astrophysical implications. Moreover the structure of neutron rich nuclei around N=32/34 and 40 was studied. The N=28 shell closure has been studied trough the one neutron transfer reaction on {sup 44,46}Ar nuclei. Excitation energies of states in {sup 45,47}Ar nuclei have been obtained, as well as their angular momenta and spectroscopic factors. These results were used to show that N=28 is still a good magic number in the argon isotopic chain. We interpreted the evolution of the spin-orbit partner gaps in terms of the tensor monopolar proton-neutron interaction. Thanks to this latter, we showed it is not necessary to summon up a reduction of the intensity of the spin-orbit force in order to explain this evolution in N=29 isotopes from calcium to argon chains. The neutron capture rates on {sup 44,46}Ar have been determined thanks to the results of the transfer reaction. Their influence on the nucleosynthesis of {sup 46,48}Ca was studied. We proposed stellar conditions to account for the abnormal isotopic ratio observed in the Allende meteorite concerning {sup 46,48}Ca isotopes. The beta decay and gamma spectroscopy of neutron rich nuclei in the scandium to cobalt region has been studied. We showed that beta decay process is dominated by the {nu}f{sub 5/2} {yields} {pi}f{sub 7/2} Gamow-Teller transition. Moreover, we demonstrated that the {nu}g{sub 9/2} hinders this process in the studied nuclei, and influences their structure, by implying the existence of isomers. Our results show that N=34 is not a magic number in the titanium chain and the superior ones. (author)

  4. Investigation of local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds using perturbed angular correlation gamma-gamma spectroscopy; Investigacao do magnetismo local em compostos intermetalicos do tipo RZn (R = Ce, Gd, Tb, Dy) e GdCu pela espectroscopia de correlacao angular gama-gama perturbada

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Brianna Bosch dos

    2010-07-01

    This work presents, from a microscopic point of view, a systematic study of the local magnetism in RZn (R = Ce, Gd, Tb, Dy) and GdCu intermetallic compounds through measurements of hyperfine interactions using the Perturbed Angular Correlation Gamma- Gamma Spectroscopy technique with {sup 111}In {yields} {sup 111}Cd and {sup 140}La {yields} {sup 140}Ce as probe nuclei. As the magnetism in these compounds originates from the 4f electrons of the rare-earth elements it is interesting to observe in a systematic study of RZn compounds the behavior of the magnetic hyperfine field with the variation of the number of 4f electrons in the R element. The use of probe nuclei {sup 140}La {yields} {sup 140}Ce is interesting because Ce{sup +3} ion posses one 4f electron which may contribute to the total hyperfine field, and the results showed anomalous behavior. The results for {sup 111}Cd probe showed that the temperature dependence of the magnetic hyperfine field follows the Brillouin function, and the magnetic hyperfine field decreases linearly with increase of the atomic number of rare earth when plotted as a function of the rare-earth J spin projection, showing that the main contribution to the magnetic hyperfine field in RZn compounds comes from the polarization of the conduction electrons. The results for the electric field gradient measured with {sup 111}Cd for all compounds showed a strong decrease with the atomic number of the rare-earth element. We have therefore assumed that the major contribution to the electric field gradient originates from the 4f electrons of the rare-earths. The measurements of the electric field gradient for GdCu with {sup 111}Cd, after temperature decreases and increases again showed that two different structures, CsCl-type cubic and FeB-type orthorhombic structures co-exist. Finally, it is the first time that measurements of hyperfine parameters have been carried out with theses two probe nuclei in the studied RZn. (author)

  5. The neutron–gamma Feynman variance to mean approach: Gamma detection and total neutron–gamma detection (theory and practice)

    Energy Technology Data Exchange (ETDEWEB)

    Chernikova, Dina, E-mail: dina@nephy.chalmers.se [Chalmers University of Technology, Department of Applied Physics, Nuclear Engineering, Fysikgården 4, SE-412 96 Göteborg (Sweden); Axell, Kåre [Chalmers University of Technology, Department of Applied Physics, Nuclear Engineering, Fysikgården 4, SE-412 96 Göteborg (Sweden); Swedish Radiation Safety Authority, SE-171 16 Stockholm (Sweden); Avdic, Senada [University of Tuzla, Department of Physics, 75000 Tuzla, Bosnia and Herzegovina (Bosnia and Herzegovina); Pázsit, Imre; Nordlund, Anders [Chalmers University of Technology, Department of Applied Physics, Nuclear Engineering, Fysikgården 4, SE-412 96 Göteborg (Sweden); Allard, Stefan [Chalmers University of Technology, Department of Chemical and Biological Engineering, Nuclear Chemistry and Industrial Materials Recycling, Kemivagen 4, SE-412 96 Göteborg (Sweden)

    2015-05-11

    Two versions of the neutron–gamma variance to mean (Feynman-alpha method or Feynman-Y function) formula for either gamma detection only or total neutron–gamma detection, respectively, are derived and compared in this paper. The new formulas have particular importance for detectors of either gamma photons or detectors sensitive to both neutron and gamma radiation. If applied to a plastic or liquid scintillation detector, the total neutron–gamma detection Feynman-Y expression corresponds to a situation where no discrimination is made between neutrons and gamma particles. The gamma variance to mean formulas are useful when a detector of only gamma radiation is used or when working with a combined neutron–gamma detector at high count rates. The theoretical derivation is based on the Chapman–Kolmogorov equation with the inclusion of general reactions and corresponding intensities for neutrons and gammas, but with the inclusion of prompt reactions only. A one energy group approximation is considered. The comparison of the two different theories is made by using reaction intensities obtained in MCNPX simulations with a simplified geometry for two scintillation detectors and a {sup 252}Cf-source. In addition, the variance to mean ratios, neutron, gamma and total neutron–gamma are evaluated experimentally for a weak {sup 252}Cf neutron–gamma source, a {sup 137}Cs random gamma source and a {sup 22}Na correlated gamma source. Due to the focus being on the possibility of using neutron–gamma variance to mean theories for both reactor and safeguards applications, we limited the present study to the general analytical expressions for Feynman-alpha formulas.

  6. The neutron–gamma Feynman variance to mean approach: Gamma detection and total neutron–gamma detection (theory and practice)

    International Nuclear Information System (INIS)

    Two versions of the neutron–gamma variance to mean (Feynman-alpha method or Feynman-Y function) formula for either gamma detection only or total neutron–gamma detection, respectively, are derived and compared in this paper. The new formulas have particular importance for detectors of either gamma photons or detectors sensitive to both neutron and gamma radiation. If applied to a plastic or liquid scintillation detector, the total neutron–gamma detection Feynman-Y expression corresponds to a situation where no discrimination is made between neutrons and gamma particles. The gamma variance to mean formulas are useful when a detector of only gamma radiation is used or when working with a combined neutron–gamma detector at high count rates. The theoretical derivation is based on the Chapman–Kolmogorov equation with the inclusion of general reactions and corresponding intensities for neutrons and gammas, but with the inclusion of prompt reactions only. A one energy group approximation is considered. The comparison of the two different theories is made by using reaction intensities obtained in MCNPX simulations with a simplified geometry for two scintillation detectors and a 252Cf-source. In addition, the variance to mean ratios, neutron, gamma and total neutron–gamma are evaluated experimentally for a weak 252Cf neutron–gamma source, a 137Cs random gamma source and a 22Na correlated gamma source. Due to the focus being on the possibility of using neutron–gamma variance to mean theories for both reactor and safeguards applications, we limited the present study to the general analytical expressions for Feynman-alpha formulas

  7. Verification of gamma-spectroscopy programs

    International Nuclear Information System (INIS)

    The newly revised ANSI N42.141,2 has provided analysis software developers with a set of well defined, consistend and unbiased procedures designed to evaluate the accuracy and limitations of peak search and peak area analysis programs. This work uses two of the procedures outlined in this standard to evaluate five peak analysis algorithms currently in use in Canberra and Nuclear Data software packages. The first procedure examines a program's behavior as the centroid separation and peak height ratio of a doublet are varied. A previous review of these data3 demonstrated significant peak area inaccuracies at peak separations at or below 1.5 FWHM. We will discuss improvements made to some of these programs and the impact on the doublet results. The second procedure examines a program's behavior as the Compton continuum beneath a fixed peak area is increased. For the same five algorithms we will discuss the dependence of peak area on Compton continuum and also explore the limits of peak detectability. (author) 4 refs.; 3 figs

  8. Development of gamma spectrometer using silicon photomultiplier (SiPM)

    International Nuclear Information System (INIS)

    Gamma spectroscopy is used to determine the identity and quantity of gamma-emitters in nuclear physics, geochemistry and astrophysics. The scintillation detectors are being used as a gamma spectrometer generally, because of their higher gamma-ray detection efficiency and cheaper price than germanium semi-conductor detectors. A typical scintillation detector is composed of a scintillator, a window, and a photodetector. The photomultiplier (PM) tube has been the most widely used as a photodetector because of its advantages like high sensitivity, high signal-to-noise ratio, and wide dynamic range. Recently, the Silicon Photomultiplier (SiPM) is being studied as a substitute of PM tube. The SiPM has almost same performance compared to PM tube but it has additional advantages; low operating voltage, small volume, and cheap production cost. In this research, the gamma spectrometer using SiPM instead of PM tube is developed. The use of SiPM as a photodetector makes the gamma spectrometer smaller, cheaper, easier to use. For photon transport and collection from the large area scintillator to the small area SiPM, a light guide is applied in this gamma spectrometer system. Before fabrication of light guide, DETECT simulation is performed to study and prospect characteristics of light guide structure. And actual light guides are fabricated on the basis of this simulation result. Poly(methyl methacrylate) (PMMA) is chosen as material of light guide, 5 sample light guides are fabricated in different lengths and coatings. As a scintillator crystal, same NaI(Tl) crystal is chosen. For measurement and analysis of gamma spectrometer system, 3 gamma spectrometer systems are composed: PM tube-based system, PM tube-based system with the light guide, SiPM-based system with the light guide. Through comparison between the results of each gamma spectrometer, the performances of gamma spectrometer system are analyzed by each component. Measurement results of the second system is well

  9. Fusion-Fission process and gamma spectroscopy of binary products in light heavy ion collisions (40 {<=} A{sub CN} {<=} 60); Processus de fusion-fission et spectroscopie gamma des produits binaires dans les collisions entre ions lourds legers (40 {<=} A{sub NC} {<=} 60)

    Energy Technology Data Exchange (ETDEWEB)

    Nouicer, Rachid [Institut de Recherche Subatomique, CNRS-IN2P3 - Universite Louis Pasteur, 67 - Strasbourg (France)

    1997-11-21

    During the work on which this Thesis is based, the significant role of the Fusion-Fission Asymmetric mechanism in light heavy ion collisions (A{sub NC} {<=} 60) has been emphasized. The Spin Dis-alignment in the oblate-oblate system has supplied evidence for the first time for the Butterfly mode in a resonant-like reaction. These two aspects, one macroscopic and the other more closely related to microscopic effects are certainly different from a conceptual point of view but are quite complementary for a global understanding of dinuclear systems. In the first part, inclusive and exclusive measurements of the {sup 35}Cl + {sup 12}C and {sup 35}Cl + {sup 24}Mg reaction have been performed at 8 MeV/nucleon in the Saclay experiment. These measurements have permitted us to verify the origin of products which have given rise of the asymmetric fusion-fission mechanism and which have demonstrated that the three-body process in this energy range is very weak. In the second part the {sup 28}Si + {sup 28}Si reaction has been performed at the resonance energy E{sub lab}> = 111.6 MeV at Strasbourg with the Eurogam phase II multi-detector array and VIVITRON accelerator. An angular momentum J{sup {pi}} 38{sup +} for inelastic and mutual channels of the {sup 28}Si + {sup 28}Si exit channel has been measured and has supplied evidence for a spin dis-alignment which has been interpreted in the framework of a molecular model by Butterfly motion. The spectroscopic study of {sup 32}S nucleus, has revealed the occurrence of a new {gamma}-ray transition 0{sup +}(8507.8 keV) {yields} 2{sub 1}{sup +}(2230.2 keV). (author) 105 refs., 116 figs., 26 tabs.

  10. Gamma camera

    International Nuclear Information System (INIS)

    The design of a collimation system for a gamma camera for use in nuclear medicine is described. When used with a 2-dimensional position sensitive radiation detector, the novel system can produce superior images than conventional cameras. The optimal thickness and positions of the collimators are derived mathematically. (U.K.)

  11. Gamma-ray methods

    International Nuclear Information System (INIS)

    Bulk analysis techniques using gamma radiation are described. The methods include gamma-ray induced reactions, selective gamma-ray scattering and methods which rely on natural radioactivity. The gamma-ray resonance scattering technique can be used for the determination of copper and nickel in bulk samples and drill cores. The application of gamma-gamma methods to iron ore analysis is outlined

  12. Antihydrogen Experiment Gravity Interferometry Spectroscopy

    CERN Multimedia

    Gerber, S; Tietje, I C; Allkofer, Y R; Trezzi, D; Dassa, L; Rienacker, B; Khalidova, O; Ferrari, G; Krasnicky, D; Perini, D; Cerchiari, G; Belov, A; Boscolo, I; Sacerdoti, M G; Ferragut, R O; Nedelec, P; Testera, G; Hinterberger, A; Al-qaradawi, I; Malbrunot, C L S; Brusa, R S; Prelz, F; Manuzio, G; Riccardi, C; Fontana, A; Genova, P; Haider, S; Haug, F; Merkt, F; Turbabin, A; Castelli, F; Doser, M; Penasa, L; Gninenko, S; Cataneo, F; Zenoni, A; Cabaret, L; Comparat, D P; Zmeskal, J; Scampoli, P; Dudarev, A; Kellerbauer, A G; Lagomarsino, V E; Mariazzi, S; Fesel, J V; Nesteruk, K P; Eisel, W T; Carraro, C; Zavatarelli, S M

    The AEGIS experiment (Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy) has the aim of carrying out the first measurement of the gravitational interaction of antimatter to a precision of 1%, by applying techniques from atomic physics, laser spectroscopy and interferometry to a beam of antihydrogen atoms. A further goal of the experiment is to carry out spectroscopy of the antihydrogen atoms in flight.

  13. Gamma irradiation effect on the chemical composition and the antioxidant activity of Ipomoea batatas L.

    Science.gov (United States)

    Tahir, D.; Halide, H.; Wahab, A. W.; Kurniawan, D.

    2014-09-01

    The chemical composition and antioxidant activity of Ipomoea batatas L. (sweet potato) were studied by x-ray fluorescence (XRF) spectroscopy, Fourier transform infrared spectroscopy, and by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. The irradiation treatment was performed by using Cs-137 as a gamma sources in experimental equipment. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. The amount of chemical composition was changed and resulting new chemical for absorbed dose 40 mSv. Interestingly, it was found that gamma irradiation significantly increased the antioxidant activity, as measured by DPPH radical scavenging capacity. The antioxidant activity of Ipomoea batatas L. extract was dramatically increased in the non-irradiated sample to the sample irradiated at 40 mSv. These results indicate that gamma irradiation of Ipomoea batatas L. extract can enhance its antioxidant activity through the formation of a new chemical compound. Based on these results, increased antioxidant activity of Ipomoea batatas L. extracts by gamma rays can be applied to various industries, especially cosmetics, foodstuffs, and pharmaceuticals.

  14. Gamma irradiation effect on the chemical composition and the antioxidant activity of Ipomoea batatas L

    Energy Technology Data Exchange (ETDEWEB)

    Tahir, D., E-mail: dtahir@fmipa.unhas.ac.id; Halide, H., E-mail: dtahir@fmipa.unhas.ac.id; Kurniawan, D. [Department of Physics, Hasanuddin University, Makassar 90245 (Indonesia); Wahab, A. W. [Department of Chemistry, Hasanuddin University, Makassar 90245 (Indonesia)

    2014-09-25

    The chemical composition and antioxidant activity of Ipomoea batatas L. (sweet potato) were studied by x-ray fluorescence (XRF) spectroscopy, Fourier transform infrared spectroscopy, and by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. The irradiation treatment was performed by using Cs-137 as a gamma sources in experimental equipment. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. The amount of chemical composition was changed and resulting new chemical for absorbed dose 40 mSv. Interestingly, it was found that gamma irradiation significantly increased the antioxidant activity, as measured by DPPH radical scavenging capacity. The antioxidant activity of Ipomoea batatas L. extract was dramatically increased in the non-irradiated sample to the sample irradiated at 40 mSv. These results indicate that gamma irradiation of Ipomoea batatas L. extract can enhance its antioxidant activity through the formation of a new chemical compound. Based on these results, increased antioxidant activity of Ipomoea batatas L. extracts by gamma rays can be applied to various industries, especially cosmetics, foodstuffs, and pharmaceuticals.

  15. Gamma irradiation effect on the chemical composition and the antioxidant activity of Ipomoea batatas L

    International Nuclear Information System (INIS)

    The chemical composition and antioxidant activity of Ipomoea batatas L. (sweet potato) were studied by x-ray fluorescence (XRF) spectroscopy, Fourier transform infrared spectroscopy, and by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity. The irradiation treatment was performed by using Cs-137 as a gamma sources in experimental equipment. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. The amount of chemical composition was changed and resulting new chemical for absorbed dose 40 mSv. Interestingly, it was found that gamma irradiation significantly increased the antioxidant activity, as measured by DPPH radical scavenging capacity. The antioxidant activity of Ipomoea batatas L. extract was dramatically increased in the non-irradiated sample to the sample irradiated at 40 mSv. These results indicate that gamma irradiation of Ipomoea batatas L. extract can enhance its antioxidant activity through the formation of a new chemical compound. Based on these results, increased antioxidant activity of Ipomoea batatas L. extracts by gamma rays can be applied to various industries, especially cosmetics, foodstuffs, and pharmaceuticals

  16. Applications of transient Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Transient effects in Moessbauer spectroscopy were generated by sweeping the frequency or switching the phase of recoilless gamma radiation. From a sinusoidal frequency sweep a separation of source and absorber contributions to the experimental linewidth was obtained. With phase switching exceptionally large effects were observed. The experimental results were obtained mainly using the 67Zn resonance. (Auth.)

  17. NMR spectroscopy

    International Nuclear Information System (INIS)

    The book reviews the applications of NMR-spectroscopy in medicine and biology. The first chapter of about 40 pages summarizes the history of development and explains the chemical and physical fundamentals of this new and non-invasive method in an easily comprehensible manner. The other chapters summarize diagnostic results obtained with this method in organs and tissues, so that the reader will find a systematic overview of the available findings obtained in the various organ systems. It must be noted, however, that ongoing research work and new insight quite naturally will necessitate corrections to be done, as is the case here with some biochemical interpretations which would need adjustment to latest research results. NMR-spectroscopy is able to measure very fine energy differences on the molecular level, and thus offers insight into metabolic processes, with the advantage that there is no need of applying ionizing radiation in order to qualitatively or quantitatively analyse the metabolic processes in the various organ systems. (orig./DG) With 40 figs., 4 tabs

  18. GARCH Gamma

    OpenAIRE

    Robert F. Engle; Joshua V. Rosenberg

    1995-01-01

    This paper addresses the issue of hedging option positions when the underlying asset exhibits stochastic volatility. By parameterizing the volatility process as GARCH, and utilizing risk- neutral valuation, we estimate hedging parameters (delta and gamma) using Monte-Carlo simulation. We estimate hedging parameters for options on the Standard and Poor's 500 index, a bond futures index, a weighted foreign exchange rate index, and an oil futures index. We find that Black-Scholes and GARCH delta...

  19. Gamma teletopography

    International Nuclear Information System (INIS)

    The mapping of gamma sources radiation emission in a nuclear plant is an important safety point. A remote gamma ray mapping process was developed in SPS/CEA/SACLAY. It uses the ''pinhole camera'' principle, precursor of photography. It mainly consists of a radiation proof box, with a small orifice, containing sensitive emulsions at the opposite. A first conventional photographic type emulsion photographs the area. A second photographic emulsion shows up the gamma radiations. The superim position of the two shots gives immediate informations of the precise location of each source of radiation in the observed area. To make easier the presentation and to improve the accuracy of the results for radiation levels mapping, the obtained films are digitally processed. The processing assigns a colours scale to the various levels of observed radiations. Taking account physical data and standard parameters, it gets possible to estimate the dose rate. The device is portable. Its compactness and fully independent nature make it suitable for use anywhere. It can be adapted to a remote automatic handling system, robot... so as to avoid all operator exposure when the local dose rate is too high

  20. In-beam spectroscopy of 231Pa

    International Nuclear Information System (INIS)

    Information on energy levels and on E2 and M1 matrix elements in 231Pa has been obtained using conversion-electron and gamma-ray spectroscopy following the 232Th(p, 2p)231Pa reaction and Coulomb excitation of the radioactive target 231Pa by 4He and 32S ions. The results are analyzed in the framework of the rotational model, applied to the rotational band built on the 1/2-[530] Nilsson state whose 3/2- member forms the ground state of this nucleus. The deviations of the level energies from the rigidrotor values can be described by Coriolis couplings. The analysis of the Coulomb-excitation process shows that a constant set of rotational parameters Q0, gR, gK, and b can fairly well account for the measured line intensities. (orig.)