Energy Technology Data Exchange (ETDEWEB)

A number of concrete culverts used to retrievably store drummed, dry, radioactive waste at the Savannah River Site (SRS), were suspected of containing ambiguous quantities of transuranic (TRU) nuclides. These culverts were assayed in place for Pu-239 content using thermal and fast neutron counting techniques. High resolution gamma-ray spectroscopy on 17 culverts, having neutron emission rates several times higher than expected, showed characteristic gamma-ray signatures of neutron emitters other than Pu-239 (e.g., Pu-238, Pu/Be, or Am/Be neutron sources). This study confirmed the Pu-239 content of the culverts with anomalous neutron rates and established limits on the Pu-239 mass in each of the 17 suspect culverts by in-field, non-intrusive gamma-ray measurements.

Energy Technology Data Exchange (ETDEWEB)

Massive particle candidates for dark matter provide a potentially observable signature by virtue of their annihilations in the galactic halo at a known but model-dependent rate. Possible signatures are described, including cosmic ray antiproton and gamma-ray production. (orig.).

Science.gov (United States)

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors investigated the evolution and radiation characteristics of individual neutron stars and stellar systems. The work concentrated on phenomena where new techniques and observations are dramatically enlarging the understanding of stellar phenomena. Part of this project was a study of x-ray and gamma-ray emission from neutron stars and other compact objects. This effort included calculating the thermal x-ray emission from young neutron stars, deriving the radio and gamma-ray emission from active pulsars and modeling intense gamma-ray bursts in distant galaxies. They also measured periodic optical and infrared fluctuations from rotating neutron stars and search for high-energy TeV gamma ...

Energy Technology Data Exchange (ETDEWEB)

Diffuse {gamma}-ray emission produced by the interaction of cosmic-ray particles with matter and radiation in the Galaxy can be used to probe the distribution of cosmic rays and their sources in different regions of the Galaxy. With its large field of view and long observation time, the Milagro Gamma Ray Observatory is an ideal instrument for surveying large regions of the Northern Hemisphere sky and for detecting diffuse {gamma}-ray emission at very high energies. Here, the spatial distribution and the flux of the diffuse {gamma}-ray emission in the TeV energy range with a median energy of 15 TeV for Galactic longitudes between 30{sup o} and 110{sup o} and between 136{sup o} and 216{sup o} and for Galactic latitudes between -10{sup o} and 10{sup o} are determined. The measured fluxes are consistent with predictions of ...

CERN Document Server

If the first (PopIII) stars were very massive, their final fate is to collapse into very massive black holes. Once a proto-black hole has formed into the stellar core, accretion continues through a disk. It is widely accepted, although not confirmed, that magnetic fields drive an energetic jet which produces a burst of TeV neutrinos by photon-meson interaction, and eventually breaks out of the stellar envelope appearing as a Gamma Ray Burst (GRB). Based on recent numerical simulations and neutrino emission models, we predict the expected neutrino diffuse flux from these PopIII GRBs and compare it with the capabilities of present and planned detectors as AMANDA and IceCube. If beamed into 1% of the sky, we find that the rate of PopIII GRBs is $\\le 4 \\times 10^6$ yr$^{-1}$. High energy neutrinos from PopIII GRBs could dominate the overall flux in two energy bands [$10^4 - 10^5$] GeV and [$10^5 - 10^6$] ...

CERN Document Server

Some models for quantum gravity (QG) violate Lorentz invariance and predict an energy dependence of the speed of light, leading to a dispersion of high-energy gamma-ray signals that travel over cosmological distances. Limits on the dispersion from short-duration substructures observed in gamma-rays emitted by gamma-ray bursts (GRBs) at cosmological distances have provided interesting bounds on Lorentz invariance violation (LIV). Recent observations of unprecedentedly fast flares in the very-high energy gamma-ray emission of the active galactic nuclei (AGNs) Mkn 501 in 2005 and PKS 2155-304 in 2006 resulted in the most constraining limits on LIV from light-travel observations, approaching the Planck mass scale, at which QG effects are assumed to become important. I review the current status of LIV searches using GRBs and AGN flare events, and discuss limitations of light-travel time ...

International Nuclear Information System (INIS)

New measurements of relative gamma-ray emission probabilities in the decay of "1"0"1Mo and "1"0"1Tc are reported. Previously published conversion-electron data have been used along with the gamma-ray data to formulate self-consistent decay schemes. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Because the number of neutrons and gamma rays and the energy spectrum of particles from spontaneous fission are well characterized for {sup 252}Cf, it can be used as a timed source of fission neutrons and gamma rays. The first such usage incorporated a {sup 252}Cf source into gas scintillators. This paper describes a timed source of neutrons and gamma rays made by depositing {sup 252}Cf on one electrode of a parallel plate ionization chamber that can then be used for determining detection-system characteristics. The emission time of neutrons from spontaneous fission has also been determined by recording the emission time of prompt gamma rays from a {sup 252}Cf source (not incorporated into a detector) adjacent to the surface of a solid or liquid scintillator. This well ...

Energy Technology Data Exchange (ETDEWEB)

An imaging detector for {gamma}-rays ({approx equal}1 MeV) based on minicell MWPCs with converters and a position resolution of {Delta}x=0.5 mm has been developed and tested. Very high rate capability (>10{sup 8}/cm{sup 2} s) and a special readout for suppression of scattered radiation are implemented allowing to enhance the measured contrast. The relevant physical processes are discussed and first pictures are presented. (orig.).

International Nuclear Information System (INIS)

The inverse Compton scattering between positron bunches and the Free Electron Laser (FEL) of the SuperAco storage ring generates a collimated and tunable gamma-ray beam. The use of the FEL instead of a conventional laser, automatically provides the transverse alignment and synchronisation of the electron and optical beams. The Super-ACO FEL is operated in the 300-430 nm range at 800 MeV with a high repetition rate (8 MHz) and an average transmitted power of 300 mW at 350 nm. High energy gamma rays of 35 MeV are produced with a rate of 1.5 10 7 photons/second and good monocromaticity (about 10%). Applications of the SuperAco FEL installation for diamond irradiation and biological studies are envisaged. (author)

CERN Document Server

We calculate the structure of accretion disks around Kerr black holes for accretion rates 0.001 - 10 M_sun/s. Such disks are plausible candidates for the central engine of gamma-ray bursts. Our disk model is fully relativistic and treats accurately microphysics of the accreting matter: neutrino emissivity, opacity, electron degeneracy, and nuclear composition. The neutrino-cooled disk forms above a critical accretion rate that depends on the black hole spin. The disk has the ``ignition'' radius r_ign where neutrino flux rises dramatically, cooling becomes efficient, and the proton-to-nucleon ratio Y_e drops. Other characteristic radii are r_alpha where most of alpha-particles are disintegrated, r_nu where the disk becomes neutrino-opaque, and r_trap where neutrinos get trapped and advected into the black hole. We find r_alpha, r_ign, r_nu, r_trap and show their dependence on the accretion ...

CERN Document Server

Primordial black holes are unique probes of cosmology, general relativity, quantum gravity and non standard particle physics. They can be considered as the ultimate particle accelerator in their last (explosive) moments since they are supposed to reach, very briefly, the Planck temperature. Upper limits on the primordial black hole number density of mass $M_{\\star} = 5 10^{14}$ g, the Hawking mass (born in the big-bang terminating their life presently), is determined comparing their predicted cumulative $\\gamma$-ray emission, galaxy-wise, to the one observed by the EGRET satellite, once corrected for non thermal $\\gamma$-ray background emission induced by cosmic ray protons and electrons interacting with light and matter in the Milky Way. A model with free gas emissivities is used to map the Galaxy in the 100 MeV photon range, where the peak of the primordial black hole ...

International Nuclear Information System (INIS)

Pregnant rats in 11d and 16d of their pregnancy were given one-off whole body exposure by "1"3"7Cs #gamma# rays to 0.2, 0.4, 0.9 and 2.0 Gy, respectively. Changes were observed in conditioned drinking response and cerebrum hippocampi cone cell number of the baby rats exposed to the #gamma# rays in different periods of their embryo development. As a result, that pregnant rats exposed to "1"3"7Cs #gamma# rays in different pregnant periods may induce significant decrease in cerebrum hippocampi cone cell number and achieving rate of conditioned drinking response of the babies. The dose-response relationship can be described by Y=a-b log_1_0D. The achieving rate of conditioned drinking response were significantly correlated to cerebrum hippocampi cone cell number in the babies, and the achieving rate of ...

CERN Document Server

In a recent paper by Hooper and Goodenough, data from the Fermi Gamma Ray Telescope was analyzed and an excess of gamma rays was found in the emission spectrum from the Galactic Center Region. Hooper and Goodenough show that the excess can be well explained by 7-10 GeV annihilating dark matter with a power law density profile if the dark matter annihilates predominantly to tau pairs. In this paper we present such a dark matter model by extending the MSSM to include four Higgs doublets and one scalar singlet. A Z2 symmetry is imposed that enforces a Yukawa structure so that the up quarks, down quarks, and leptons each receive mass from a distinct doublet. This leads to an enhanced coupling of scalars to leptons and allows the model to naturally achieve the required phenomenology in order to explain the gamma ray excess. Our model yields the ...

Energy Technology Data Exchange (ETDEWEB)

A theoretical model is developed to explain variations in airborne gamma-ray measurements over a calibration range near Ottawa, Ontario. The gamma-ray flux from potassium and the thorium decay series showed an expected decrease with increasing soil moisture. However, the gamma-ray flux from the uranium decay series was highest in the spring when the ground was water-saturated and even covered with snow. These results are explained through the build-up of radon and its associated gamma-ray-emitting decay products in the clay soil of the calibration range with increasing soil moisture. Similar results were found from airborne measurements over other clay soils. However, measurements over sandy soils showed that the count rates from all three radio elements increased with decreasing soil moisture. This difference between soil types was attributed to the lower radon emanation of the ...

CERN Document Server

The WIDeField telescope for Gamma-ray burst Early Timing (WIDGET) is used for a fully automated, ultra-wide-field survey aimed at detecting the prompt optical emission associated with Gamma-ray Bursts (GRBs). WIDGET surveys the HETE-2 and Swift/BAT pointing directions covering a total field of view of 62 degree x 62 degree every 10 secounds using an unfiltered system. This monitoring survey allows exploration of the optical emission before the gamma-ray trigger. The unfiltered magnitude is well converted to the SDSS r' system at a 0.1 mag level. Since 2004, WIDGET has made a total of ten simultaneous and one pre-trigger GRB observations. The efficiency of synchronized observation with HETE-2 is four times better than that of Swift. There has been no bright optical emission similar to that from GRB 080319B. The statistical analysis implies that GRB080319B is a ...

CERN Document Server

In a recent study of a search for enhancements from the galactic center with muons at sea level using the TUPI muon telescope, we have found several ground level enhancements (GLEs) as very sharp peaks above the count rate background. This paper reports a consistent analysis of two GLEs observed in December 2003 and detected after an up-grade of the data acquisition system, which includes a noise filter and which allows us to verify that the GLEs are not mere background fluctuations. The main target of this study is a search for the origin of the GLEs. The results show that one of them has a strong correlation with a solar flare, while the other has an unknown origin, because there is neither a satellite report of a solar flare, nor prompt X-ray emission, and nor a excess of nuclei during the raster scan where the GLE was observed. Even so, two possibilities are analyzed: the solar flare hypothesis and the gamma ...

CERN Document Server

The nature of the hard X-ray source XSSJ12270-4859 is still unclear though it was claimed to be a magnetic Cataclysmic Variable. We here present a broad-band X-ray and gamma ray study based on a recent XMM-Newton observation and archival INTEGRAL and RXTE data. From the Fermi/LAT 1-year point source catalogue, we tentatively associate XSSJ12270-4859 with 1FGLJ1227.9-4852, a source of high energy gamma rays with emission up to 10GeV. We complement the study with UV photometry from XMM-Newton and ground-based optical and near-IR photometry. The X-ray emission is highly variable showing flares and intensity dips. The X-ray flares consist of flare-dip pairs. Flares are also detected in the UV range but not the dips. Aperiodic dipping behaviour is also observed during X-ray quiescence but not in the UV. The 0.2-100keV spectrum is featureless and described by a power ...

CERN Document Server

We discuss optimal detection of fast radio transients from astrophysical objects while taking into account the effects of propagation through intervening ionized media, including dispersion, scattering and scintillation.Our analysis applies to the giant-pulse phenomenon exhibited by some pulsars, for which we show examples, and to radio pulses from other astrophysical sources, such as prompt radio emission from gamma-ray burst sources and modulated signals from extra-terrestrial civilizations.

International Nuclear Information System (INIS)

Conversion electron studies of medium-heavy to heavy nuclear mass systems are important where the internal conversion process begins to dominate over gamma-ray emission. The use of a segmented detector array sensitive to conversion electrons has been used to study multiple conversion electron cascades from nuclear transitions. The application of the silicon array for conversion electron detection (SACRED) for in-beam measurements has successfully been implemented. (orig.). With 2 figs.

CERN Document Server

The central engine of Gamma Ray Bursts is hidden from direct probing with photons mainly due to the high densities involved. Inferences on their properties are thus made from their cosmological setting, energetics, low-energy counterparts and variability. If GRBs are powered by hypercritical accretion onto compact objects, on small spatial scales the flow will exhibit fluctuations, which could in principle be reflected in the power output of the central engine and ultimately in the high energy prompt emission. Here we address this issue by characterizing the variability in neutrino cooled accretion flows through local shearing box simulations with magnetic fields, and then convolving them on a global scale with large scale dynamical simulations of accretion disks. The resulting signature is characteristic, and sensitive to the details of the cooling mechanism, providing in principle a discriminant for GRB central engine ...

Science.gov (United States)

We present an estimate of the Gamma Ray Bursts which should be expected from metal-free, elusive first generation of stars known as PopulationIII (PopIII). We derive the GRB rate from these stars from the Stellar Formation Rate obtained in several Reionization scenarios available in the literature. In all of the analyzed models we find that GRBs from PopIII are subdominant with respect to the ''standard'' (PopII) ones up to z {approx} 10.

CERN Document Server

We construct models for gamma-ray bursts where the emission comes from internal shocks in a relativistic wind with a highly non uniform distribution of the Lorentz factor. We follow the evolution of the wind using a very simplified approach where a large number of layers interact by direct collisions but where all pressure waves have been suppressed. We suppose that the magnetic field and the electron Lorentz factor reach large equipartition values in the shocks. Synchrotron photons emitted by the relativistic electrons have a typical energy in the gamma-ray range in the observer frame. Synthetic bursts are constructed as the sum of the contributions from all the internal elementary shocks and their temporal and spectral properties are compared to the observations. We reproduce the diversity of burst profiles, the ``FRED'' shape of individual pulses and the short time scale variability. Synthetic bursts also satisfy the ...

Energy Technology Data Exchange (ETDEWEB)

Characterization of high temperature superconducting film and bulk samples has been carried out using 2 MeV [alpha]-particle Rutherford backscattering, 2.4 MeV proton elastic scattering, 2.4 MeV proton-induced x-ray emission, 9 MeV proton induced [gamma]-ray emission and 100 MeV iodine elastic recoil detection analysis techniques. The objective was to compare different ion beam based techniques for: (i) compositional analysis; and (ii) consistency of the results obtained for samples prepared using similar preparation methodology. (author).

International Nuclear Information System (INIS)

Radiation modification on liquid retention properties of native cassava starch, gelatinized at 85"0C, by graft copolymerization with acrylonitrile was carried out by mutual irradiation to #gamma#-rays. A thin aluminium foil was used to cover the inner wall of the reaction vessel so that the extent of homo polymer could be reduced to be less than 1.6% with a distilled water retention value of 665 g/g of the dry weight of the saponified grafted product. Confirmations of graft copolymerization and saponification reactions were made by the infrared spectrophotometric technique. The combined effect of radiation parameters in terms of an irradiation time and a dose rate to the same total dose on the extent of grafting reaction expressed in terms of grafting parameters which directly influenced liquid retention values was evaluated in conjunction with statistical analysis.

International Nuclear Information System (INIS)

Changing cream pearls into bluish-grey by #gamma# ray irradiation is a technique in coloring of pearls. Irradiated pearls are similar in color to cultured blue pearls. The pearl layers hardly change their color but the nuclei change into dark brown by irradiation. Visible light (500 - 700 nm) penetrating the pearl layer is absorbed by dark brown nucleus. The intensity of reflecting light between 400 and 500 nm at pearl surface, therefore, becomes stronger than that between 500 and 700 nm; therefore color of irradiated pearls look bluish-grey. The density of bluish-grey color increases with increasing absorbed doses, but their luster at surface diminishes owing to the deterioration of the pearl layer by prolonged irradiation; high doses irradiation should be avoided. Irradiated pearls show no substantial fading of their color in a year and the rate of the fading is found to be lower than that for cultured blue pearls. ...

International Nuclear Information System (INIS)

We study the spectral evolution of pulsar wind nebulae (PWNe) taking into account the energy injected when they are young. We model the evolution of the magnetic field inside a uniformly expanding PWN. Considering time-dependent injection from the pulsar and coolings by radiative and adiabatic losses, we solve the evolution of the particle distribution function. The model is calibrated by fitting the calculated spectrum to the observations of the Crab Nebula at an age of a thousand years. The spectral evolution of the Crab Nebula in our model shows that the flux ratio of TeV #gamma#-rays to X-rays increases with time, which implies that old PWNe are faint in X-rays, but not in TeV #gamma#-rays. The increase of this ratio is because the magnetic field decreases with time and is not because the X-ray emitting particles are cooled more rapidly than the TeV #gamma#-ray emitting particles. Our spectral evolution model matches ...

Energy Technology Data Exchange (ETDEWEB)

The themal neutron sensitivities of SEI and Toshiba FD-P10-7 radiophotoluminescent silver activated metaphosphate glass dosimeters have been measured and studied theoretically. The graphite thermal neutron column attached to the AEEW reactor NESTOR was utilised as a source of thermal neutrons with minimal fast neutron and gamma-ray contamination. Both the neutron removal and gamma correction measurement techniques were applied and these gave consistent results. It was found that the thermal neutron sensitivity of the Toshiba dosimeters is comparable to the most neutron intensitive thermoluminescent materials available. Because of their larger size and higher silver concentration, however, SEI dosimeters are an order of magnitude more neutron sensitive. The neutron sensitivity of FD-7 glass has not been reported previously, whereas in the case of SEI glass, there exists a modest body of previous work on dosimeters of nominally identical composition. The present ...

International Nuclear Information System (INIS)

A high resolution Compton telescope has been identified by the Gamma Ray Astronomy Program Working Group (GRAPWG) as the highest priority major mission in gamma ray astrophysics following GLAST. This mission should provide 25-100 times improved sensitivity, relative to CGRO and INTEGRAL, for MeV gamma ray lines. It must have good performance for narrow and broad lines and for discrete and diffuse emissions. Several instrumental approaches are being pursued to achieve these goals. We discuss issues relating to this mission including alternative detector concepts, instrumental configurations, and background reduction techniques. We have pursued the development of position-sensitive solid-state detectors (Ge, Si) for a high spectral resolution Compton telescope mission. A #approx#1 m2 germanium Compton telescope of position-sensitive germanium ...

International Nuclear Information System (INIS)

An aerial radiological survey was performed from 11 to 20 March 1982 over a 260-square-kilometer area centered on the Grand Gulf Nuclear Station at Port Gibson, Mississippi (the station was not yet in operation at the time of the survey). All gamma ray data were collected by flying east-west lines spaced 152 meters apart at an altitude 91 meters above ground level. Processed data showed that all gamma rays detected within the survey area were those expected from naturally occurring terrestrial background emitters. Count rates obtained from the aerial platform were converted to exposure rates at 1 meter above the ground and are presented in the form of an isoradiation contour map. The observed exposure rates were between 5 and 13 microroentgens per hour (#mu#R/h), with most of the area ranging from 9 to 10 #mu#R/h. These values include an ...

International Nuclear Information System (INIS)

The present study was designed to assess the radioprotective effects of amifostine on ovarian follicles. Three week-old female mice with or without pretreatment of amifostine were irradiated with 6.42 Gy of #gamma# -ray. Ovaries were collected 0 and 6h after irradiation. DNA fragmentation pattern and expression of genes and activity of proteins related with apoptosis were investigated by means of RT-PCR and Western blot. Proliferation of granulosa cells was reduced and incidence rate of follicular atresia was increased in ovarian follicles in #gamma# -ray irradiated mice compared to those in control or amifostine-treated group. DNA fragmentation was increased in time-dependent manner in granulosa cells of all irradiated groups. However, no difference between amifostine pre-treated group and irradiated groups was found and the expression of p53 as tumor suppressor gene and Bax as one ...

Energy Technology Data Exchange (ETDEWEB)

The rates of hydrogen release from simulated high-level liquid waste (SHLLW) during irradiation of {sup 60}Co {gamma}-rays have been studied using a laboratory-scale apparatus. The SHLLW used was made up of 28 different metal elements, the concentrations of which were determined from a computed data (ORIGEN-2) for a Purex spent fuel (burn-up of 4.5 GWd/t, cooling time of 4 years) except for those of corrosion products (Fe, Cr and Ni) and of chemical process additive (P). The nitrate ion concentration of the SHLLW was 4.97 M. The G-value of hydrogen release was 0.0164 for stirred conditions, but for nonstirred conditions with dose rate : 2.8 kGy/h and with the SHLLW solution height more than 8 cm, the following relation was found between the G-value and the solution height (d cm); G(H{sub 2}) = 0.100 d{sup -1.6}. The G-values of oxygen and nitrogen releases were also determined. (author)

International Nuclear Information System (INIS)

An aerial radiological survey was conducted over the Department of Energy's Hanford Site near Richland, Washington, during the period 5 July through 26 August 1988. The survey was expanded, and additional flights were conducted to the east of the site and along the banks of the Columbia River down to McNary Dam near Umatilla. The survey was flown at altitude of 61 meters (200 feet) by a helicopter containing 17 liters (eight 2 in. x 4 in. x 16 in.) of sodium iodide detectors. Gamma ray data were collected over the survey area by flying north-south lines spaced 122 meters (400 feet) apart. The processed data indicated that detected radioisotopes and their associated gamma ray exposure rates were generally consistent with those expected from normal background emitters and man-made fission/activation products resulting from activities at the site. External exposure ...

International Nuclear Information System (INIS)

The emission of #alpha# particles in coincidence with the most deeply inelastic heavy-ion reactions has been studied for "1"8"1Ta + "1"6"5Ho at 1354 MeV laboratory energy and /sup nat/Ag + "8"4Kr at 664 MeV. #alpha# particle energy spectra and angular distributions, in coincidence with a projectile-like fragment, were acquired both in the reaction plane and out of the reaction plane at a fixed in-plane angle. The in-plane data for both systems are employed to show that the bulk of the #alpha# particles in coincidence with the deep-inelastic exit channel can be explained by evaporation from the fully accelerated fragments. Average velocity diagrams, #alpha#-particle energy spectra as a function of angle in several rest frames, and #alpha#-particle angular distributions are presented. The out-of-plane #alpha# particle angular distributions and the #gamma#-ray multiplicities are used to study the transfer and partitioning of angular momentum ...

CERN Document Server

The true nature of the progenitor to GRBs remains elusive; one characteristic that would constrain our understanding of the GRB mechanism considerably is gamma-ray polarimetry measurements of the initial burst flux. We present a method that interprets the prompt GRB flux as it Compton scatters off the Earth's atmosphere, based on detailed modelling of both the Earth's atmosphere and the orbiting detectors. The BATSE mission aboard the \\textit{CGRO} monitored the whole sky in the 20 keV - 1 MeV energy band continuously from April 1991 until June 2000. We present the BATSE Albedo Polarimetry System (BAPS), and show that GRB 930131 and GRB 960924 provide evidence of polarisation in their prompt flux that is consistent with degrees of polarisation of $\\Pi>35$% and $\\Pi>50$% respectively. While the evidence of polarisation is strong, the method is unable to strongly constrain the degree of polarisation beyond a systematics based estimation. Hence the ...

Energy Technology Data Exchange (ETDEWEB)

The goal of this DOE-supported exhibition is to demystify Einstein`s formula E = mc{sup 2} by illustrating the interchangeability of matter (m) and energy (E), c{sup 2} being the exchange rate. The exhibition has two major parts, {open_quotes}matter into energy{close_quotes} and {open_quotes}energy into matter{close_quotes}, plus a video to connect them. {open_quotes}Matter into energy{close_quotes} has now been completed and has been placed on the museum floor. Positrons from a {sup 22}Na source are annihilated to produce gamma rays that are caught in NaI detectors. The viewer can alter the alignment of the detectors and observe the consequences for the rates of single and coincident counts. The viewer can also observe the effects of placing absorbers in front of the counters. Prototype explanatory graphics were placed around the exhibit and those will probably be changed after we have some experience ...

Energy Technology Data Exchange (ETDEWEB)

Proton induced X-ray emission (PIXE) and proton induced {gamma}-ray emission (PIGE) techniques are employed for the determination of essential and trace elements in some commonly used medicinal plants of north east India. Light elements such as Na, Mg, Al and P are determined by PIGE while medium Z elements such as K, Ca, Mn, Fe, Cu, Zn, Rb and Sr are determined by PIXE. Analysis is performed on pellets (thick targets) prepared using powders of the specimens which, in turn, are obtained following a series of processing steps. Plant based biological certified reference materials (CRMs) served as standards for quantification. These elements are found to be present in varying concentrations in the studied plants, with the contents of Mn and Zn being notably large in certain specimens. Medicinal properties possessed by these plants have been correlated with their elemental distribution.

Energy Technology Data Exchange (ETDEWEB)

Natural rubber latexes were vulcanized by ..gamma..-rays with two polyfunctional monomers, neopentylglycol diacrylate (A-NPG) and dimethacrylate (NPG). In comparison with A-NPG, NPG was more soluble in rubber particles, but it was less effective as an accelerating agent for the vulcanization because of the smaller rate of polymerization. On the other hand, the colloidal stability of the latex containing A-NPG was low because it was localized on the surface of rubber particles due to its poor solubility to the particles. The solubility of A-NPG was improved by adding A-NPG with solvents. The maximum tensile strength of the irradiated latex film was 350 kg/cm/sup 2/ at 3 Mrad.

Energy Technology Data Exchange (ETDEWEB)

Methylmethacrylate polymerisation in the presence of 4 wt% butadiene-acrylonitrile rubber was carried out at fixed dose-rate and temperature. The effect of irradiation was investigated with respect to the mechanical and dynamic-mechanical properties in the solid state. A general increase of the 'compatibilisation' on irradiation is obtained. In fact both rubber and polymethylmethacrylate glass transition temperatures, determined through dynamic-mechanical analysis, reveal the presence of strong interactions between the components. Furthermore an improvement of the mechanical tensile properties of the blends is observed when irradiation is continued after polymerisation, at least until a certain absorbed dose.

British Library Electronic Table of Contents (United Kingdom)

Purpose Study the radiolysis of solid-state metoclopramide hydrochloride at various absorbed doses. Elucidate the structure of the degradation products to gain information on the radiolysis mechanisms. Methods Solid-state metoclopramide samples were irradiated at several doses with gamma rays and high-energy electrons to evaluate the influence of the dose rate. High-performance liquid chromatography with a diode array detector was used to measure the chemical potency as a function of the absorbed dose and to quantify the degradation products. The characterization of degradation products was performed by liquid chromatography/atmospheric pressure chemical ionization/tandem mass spectrometry. Results The degradation of solid-state metoclopramide after irradiation was negligible. No qualitati...

CERN Document Server

Context: The colliding-wind binary Eta Car exhibits soft X-ray thermal emission that varies strongly around periastron, and non-thermal emission seen in hard X-rays and gamma-rays. Aims: To definitively identify Eta Car as the source of the hard X-ray emission, to examine how changes in the 2-10 keV band influence changes in the hard X-ray band, and to understand more clearly the mechanisms producing the non-thermal emission using new INTEGRAL observations obtained close to periastron. Methods: A Chandra observation encompassing the ISGRI error circle was analysed, and all other soft X-ray sources (including the outer shell of Eta Car itself) were discarded as likely counter-parts. New hard X-ray images of Eta Car were studied close to periastron, and compared to previous observations far from periastron. Results: The INTEGRAL component, when represented by a power law (with a ...

Science.gov (United States)

The research sponsored by this grant was conducted in two fields of high-energy astrophysics:

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

This patent describes a {gamma}-ray detector. It comprises: a dislocation-free single crystal having an input surface and a transmission surface at opposite ends thereof; an active shield surrounding the crystal and functioning as an anticoincidence counter; and {gamma}-ray detector means disposed adjacent the transmission surface of the crystal for receiving and detecting {gamma}-rays of a predetermined wavelength incident on the input surface of the crystal at a specific Bragg angle and transmitted through the crystal.

Energy Technology Data Exchange (ETDEWEB)

A thermal-resistant radiation sensing system using optical fiber has been developed. The system is for monitoring progress of chemical decontamination and able to measure the gamma-ray level in a hot solution of decontamination chemicals in situ. Our sensor head makes use of thermal-resistant NaI (T1) and it is connected to an optical fiber bundle. Scintillation photons pass from the NaI (T1) into the end of the bundle. This part of the system can withstand temperatures of over 100degC. At the far end of the optical fiber bundle, the scintillation photons are converted into fluorescent photons using a wavelength-shifting fiber. These photons are transferred to a distant photomultiplier tube through two thin transparent optical fibers. Furthermore, we propose a self-compensation technique for the dependence of scintillator sensitivity on. This compensation method is based on the correlation between temperature, sensitivity, and scintillation decay time. We have ...

International Nuclear Information System (INIS)

A pilot project was started in 1977 over the Lake Superior basin to measure water storage on the land area using aerial gamma-ray spectrometry to provide hydrologic information for forecasting inflow to the lake. Two airborne surveys were made, respectively in November 1977 and March 1978 which provided estimates of the increase in snow water equivalent between these surveys. The basin is located on the Canadian Shield and consequently, the gamma radiation count rate is quite variable. The airborne results are compared with ground measurements on selected flight lines and show generally good agreement. Two equipment calibrations in the Ottawa area provided inconsistent parameter values which are consequently also reflected in the results over the Lake Superior basin. The project has demonstrated to-date that the technique can be developed into an operational system for measuring snow cover water equivalent of this vast and remote area by using ...

Energy Technology Data Exchange (ETDEWEB)

A method of detecting explosives in a vehicle includes providing a first rack on one side of the vehicle, the rack including a neutron generator and a plurality of gamma ray detectors; providing a second rack on another side of the vehicle, the second rack including a neutron generator and a plurality of gamma ray detectors; providing a control system, remote from the first and second racks, coupled to the neutron generators and gamma ray detectors; using the control system, causing the neutron generators to generate neutrons; and performing gamma ray spectroscopy on spectra read by the gamma ray detectors to look for a signature indicative of presence of an explosive. Various apparatus and other methods are also provided.

Energy Technology Data Exchange (ETDEWEB)

A method of detecting explosives in a vehicle includes providing a first rack on one side of the vehicle, the rack including a neutron generator and a plurality of gamma ray detectors; providing a second rack on another side of the vehicle, the second rack including a neutron generator and a plurality of gamma ray detectors; providing a control system, remote from the first and second racks, coupled to the neutron generators and gamma ray detectors; using the control system, causing the neutron generators to generate neutrons; and performing gamma ray spectroscopy on spectra read by the gamma ray detectors to look for a signature indicative of presence of an explosive. Various apparatus and other methods are also provided.

Energy Technology Data Exchange (ETDEWEB)

Over the last several years considerable concern has been expressed regarding the potential detrimental effects of radon and radon progeny on our health. The complex nature of the radon decay scheme, which involves the emission of a variety of radiations including several [alpha] particles, [beta] particles, and [gamma]-rays, does not lend itself to clear delineation of the biological effects of the [alpha] particles alone. Polonium-210, the terminal radionuclide of the radon decay series, is useful for this purpose because it has a relatively long shelf-life ([tau][sub 1/2] = 138 d), and it only emits a single 5.3 MeV [alpha] particle in its decay to stable [sup 206]Pb. Accordingly, it has been used extensively in radiobiological studies with incorporated radionuclides. The radionuclide [sup 210]Po is produced in a reactor from [sup 209]Bi. (Author).

International Nuclear Information System (INIS)

Nuclear shape changes can bring about rapid changes in nuclear properties. That such vibrational #-># symmetric rotor #-># asymmetric nucleus changes may be present in the A approximately 100 region is suggested by rapid, low-energy level density changes and unexpected #beta#-decay rate changes in several series of odd-odd and odd-mass fisions product nuclei. In order to define the nature of these nuclei we have performed measurements on a series of nuclei using JOSEF and Lohengrin mass separators, fast-chemistry, and n-capture #gamma#-ray techniques. Here we summarize the several features we find.

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The radiation control carried out in Atomic Energy Research Institute, Kinki University, for the reactor installation and the tracer/accelerator facilities from April, 1981, to March, 1982, is described. The reactor was operated for total 1057.1 hours at the maximum heat output of 1 W. The persons subject to radiation protection as of April, 1981, were 126 persons in all, including 23 in radiation work and 11 in X-ray work, etc. The contents of this report are as follows: personnel monitoring (health examination, the control of individual exposure dose); laboratory monitoring (the measurement of area dose rate, radioactive concentration in air and water, and surface contamination density); field monitoring (environmental ..gamma..-ray dose rate, radioactive concentration in environmental samples); the use of unsealed radioisotopes, etc.

International Nuclear Information System (INIS)

This study was undertaken at El-sahafa village, sharkia governorate, during two successive seasons (1988 and 1989) to investigate the effect of four gamma irradiation doses (0,10,20 and 40 Gy), three rates of each of superphosphate (0,100 and 200 Kg/fad.) and gypsum (0,500 and 1000 kg/fad.), as well as, three concentrations of gibberellic acid (0,50 and 100 ppm) on growth, yield and seed quality of solid and inter cropped sesame (Giza 32 cv.) and peanut (Giza 5 cv.) in one inter cropping pattern (3:3). Three separate experiments were carried out where the first one was devoted for gamma irradiation and the second for superphosphate and gypsum fertilization while the third was devoted for gibberellic acid treatment

International Nuclear Information System (INIS)

This paper first introduces the calculating method of radium specific activity to determine the radon emanation rate of tailing of uranium mine No. 794, the method needs two parameters: radon emanation coefficient and radon diffusion coefficient. According to the measured results of parameters and the contrast between radium specific activity of indoor chemical analysis of field sample and field gamma-ray spectra, the authors discuss the variation rules and characteristics of radon emanation coefficient and radon diffusion coefficient, and the best climate and seasons for measuring these parameters in northern China, and finally summarize the characteristics of this method through analyzing measured results. (authors)

Science.gov (United States)

A computer-based beam dosimetry measurement system for boron neutron capture therapy provides accurate, sensitive, and rapid readout and recording of all beam dose components, epithermal and thermal neutron flux, and gamma-ray dose rate. This dosimetric system includes input from the characterization of the epithermal neutron beam developed at the Massachusetts Institute of Technology, actual BPA pharmacokinetic data from a specific human subject being irradiated, output of MacNCTPLAN, a treatment planning system developed by the authors group, and input from the five on-line beam detectors. The purpose of this system and associated readout systems is to ensure that the desired dose is delivered to the subject within acceptable dose tolerances, e.g., {+-}5% of the target dose, and that any perturbations in the neutron beam that may occur during irradiation can be rapidly evaluated and the appropriate measures taken.

Energy Technology Data Exchange (ETDEWEB)

The mass and charge distributions in an unseparated mix of fission product nuclei from thermal-neutron fission of /sup 242m/Am were studied through semiconductor gamma-ray spectrometry. Samples of the fissionable material under study were irradiated in a vertical irradiation tube of the MIFI IRT research reactor. Following irradiation, measurements were made on aperture-calibrated semiconductor detectors. For broader identification of fission fragment nuclides three experiments were conducted that differed substantially in irradiation duration. The spectrum of gamma radiation from the mix of fission products and the time dependences of count rate at total absorption peaks were analyzed on SM-4 and Iskra-226 computers. The values of yields obtained were compared with data of investigations conducted earlier with other experimental methods, and also with the results of calculations.

International Nuclear Information System (INIS)

The excitation functions of the reactions "9"8Mo(d,p)"9"9Mo and "1"0"0Mo(d,p)"1"0"1Mo have been determined by irradiation of stacked foils with deuterons of energies less than 13 MeV and non-destructive determination of the absolute activity of the Mo radioisotopes by semiconductor #gamma#-ray spectrometry. From the excitation functions, the thick-target yields and the saturation production rates of "9"9Mo and "1"0"1Mo for deuteron energies of 13.0 MeV and 11.7 MeV have been calculated. Implications for the production of "9"9Mo for generators of sup(99m)Tc are discussed. (author).

Energy Technology Data Exchange (ETDEWEB)

To study CdZnTe as a high energy resolution gamma ray detector with a novel new design, and to build a detector array from the new detector design

Energy Technology Data Exchange (ETDEWEB)

We summarize some initial results in our investigation of the nuclear physics issues of gamma-ray lasers. We describe what is known thus far from existing experimental data and illustrate how theoretical models may be employed for systematic searches of candidate nuclei.

International Nuclear Information System (INIS)

... electrophoresis fission products gamma radiation gamma spectra half-life

Science.gov (United States)

Black holes have been predicted since the 1940's from solutions of Einstein's general relativity

Energy Technology Data Exchange (ETDEWEB)

The quantitative estimation of various trace element concentrations in medicinal plants is necessary for determining their effectiveness in treating various diseases and for understanding their pharmacological action. Elemental concentrations of some selected medicinal plants of north east India was measured by proton induced X-ray emission (PIXE) and proton induced {gamma}-ray emission (PIGE) techniques. PIXE measurements were carried out using 2.4 MeV collimated protons from the 3 MV tandetron accelerator of NCCCM, Hyderabad (India) while the PIGE measurements were carried out using 3 MeV protons from the same accelerator in the same laboratory. Accuracy and precision of the techniques were assured by analyzing certified reference materials in the same experimental conditions. Various elements of biological importance in man's metabolism were found to be present in varying concentrations in the studied medicinal ...

Energy Technology Data Exchange (ETDEWEB)

The structural variations of amorphous metals, such as Pd/sub 80/Si/sub 20/, with irradiation of helium ion, neutron, and gamma ray have been mainly pursued by the method of X-ray diffraction and thermal analysis. It should be noticed that the amorphous metals show a radiation resistance, that is, no remarkable structural changes under helium ion, neutron, and gamma ray irradiation.

Energy Technology Data Exchange (ETDEWEB)

A recently developed neutron diagnostic probe system has the potential to satisfy a significant number of van-mobile and fixed- portal requirements for nondestructive verification of sealed munitions and detection of contraband explosives and drugs. The probe is based on a unique associated-particle sealed-tube neutron generator (APSTNG) that interrogates the object of interest with a low-intensity beam of 14-MeV neutrons generated from the deuterium-tritium reaction and that detects the alpha-particle associated with each neutron. Gamma-ray spectra of resulting neutron inelastic scattering and fission reactions identify nuclides associated with all major chemicals in chemical warfare agents, explosives, and drugs, as well as many pollutants and fissile and fertile special nuclear material. Flight times determined from determined from detection times of the gamma-rays and alpha-particles yield a separate tomographic image of each identified ...

Energy Technology Data Exchange (ETDEWEB)

The energy and intensity of gamma rays as seen in thermal neutron capture are presented. Only those (n,..cap alpha..), E = thermal, reactions for which the residual nucleus mass number is greater than or equal to 45 are included. These correspond to evaluations published in Nuclear Data Sheets. The publication source data are contained in the Evaluated Nuclear Structure Data File (ENSDF). The data presented here do not involve any additional evaluation. Appendix I lists all the residual nuclides for which the data are included here. Appendix II gives a cumulated index to A-chain evaluations including the year of publication. The capture gamma ray data are given in two tables - the Table 1 is the list of all gamma rays seen in (n,..gamma..) reaction given in the order of increasing energy; the Table II lists the gamma ...

Energy Technology Data Exchange (ETDEWEB)

A complete code based on the finite element method (FEM) is used to study the attenuation of gamma rays, of source energy 9 MeV, in simple homogeneous lead and water systems. The results are compared, in tables and graphs, with those produced by a Monte Carlo method of solution. In the comparison, particular attention is paid to the annihilation gamma rays generated by the pair production process, to energy deposition, and to the leakage spectra. A model, multilayer, slab shield, having a fission neutron source impinging on the left-hand face, is also solved by the FEM code, using data from a coupled neutron/gamma ray cross section library. The resulting neutron and gamma ray flux distributions, and the leakage spectra, are shown graphically. (author).

International Nuclear Information System (INIS)

Pregnant Swiss albino mice of 18 days post conception were exposed to 0.80 Gy, 0.40 Gy and 0.20 Gy of gamma rays from a Cobalt-60 source at different dose rates (.0584 Gy/min and .00091 Gy/min). Post irradiation variations in the cell population of crypts and villus of jejunum were studied in the F_1-generation at 1 day, 3 day and 1,2,4,6 and 12 weeks of post-partum age. In all the exposure groups at 1 day post-partum age, crypts show a decrease in total cells, mitotic figures and goblet cells on one hand and an increase in PNNC on the other hand in comparison to coeval controls. At this interval a decrease in the number of total cells as well as goblet cells/villus column was also noticeable. Dead cells which were prominently seen in crypts were totally absent in villi. The first signs of recovery can be observed on day 3 p.p. when total cell population, mitotic activity and goblet cells of crypt registered an increase ...

International Nuclear Information System (INIS)

Conditions for radiation induced grafting with butyl acrylate dispersed in water emulsion onto chrome-tanned pig skins have been worked out for #gamma#-rays and electron beam irradiations. The highest yield of grafting was observed at monomer concentration approximately 25% (w/w), dose equal to 25 kGy and dose rate not exceeding 10 MGy/h. At these conditions the yield of grafting attained a value approximately 25% and content of homopolymer in the leather amounted to 6%. The efficiency of monomer to polymer conversion decreases when the concentration of monomer in emulsion and dose rate increases. Yield of homopolymer is independent of the dose rate. An explanation of the observed relations has been proposed. The physical and used properties of grafted leathers were tested. Radiation processed leathers were found superior to samples finished by traditional methods. One has to point to better tolerance ...

International Nuclear Information System (INIS)

Calculations have been made to determine the production of "1"8"8W from "1"8"6W in several US fission reactor systems, e.g., Fast Flux Test Facility (FFTF), the High Flux Isotope Reactor (HFIR), and the Advanced Test Reactor (ATR). Important input to these calculations are the cross-section parameters for "1"8"6W, "1"8"7W, and "1"8"8W. Only two values have been measured for "1"8"7W and none for "1"8"8W. Consequently, results from integral measurements play a crucial role in determining the "1"8"7W and "1"8"8W values. This has been studied for irradiations in the FFTF and the Oregon State Univ. (OSU) research reactor. Short irradiation of enriched "1"8"6W in both the FFTF and the OSU reactors have produced #mu#Ci/g quantities of "1"8"8W/"1"8"8Re. Measurements were made of the "1"8"8W gamma ray emission. These results were incorporated with other available data to provide more accurate "1"8"8W calculations in fission reactor ...

International Nuclear Information System (INIS)

The energy resolution of small NaI(Tl), CsI(Tl), BGO, GSO, YAP and LSO crystals has been studied using 16 mm diameter large area avalanche photodiodes (LAAPD) and a 52 mm diameter photomultiplier. The best result of 4.8% for 662 keV #gamma#-rays from a "1"3"7Cs source was obtained with a 9 mm in diameter by 9 mm high CsI(Tl) scintillator coupled to an LAAPD. Measuring the number of primary electron-hole pairs produced in the LAAPD and photoelectrons in the photomultiplier, as well as the noise contribution of the LAAPD, allowed a quantitative discussion of the results. The energy resolutions measured with LAAPDs are comparable to, or significantly better (at certain emission wavelengths) than, those obtained with the photomultiplier. At energies above 100 keV the energy resolution measured with the majority of crystals and the LAAPD was weakly affected by the photodiode noise contribution. The advantages and limitations of LAAPDs in energy ...

International Nuclear Information System (INIS)

An aerial radiological survey was conducted from August 10-16, 1993, over a 78-square-kilometer (30-square-mile) area of the Portsmouth Gaseous Diffusion Plant and surrounding area located near Portsmouth, Ohio. The survey was performed at a nominal altitude of 46 meters (150 feet) with a line spacing of 76 meters (250 feet). A contour map of the terrestrial gamma exposure rate extrapolated to 1 meter above ground level was prepared and overlaid on a set of United States Geological Survey topographic maps of the area and an aerial photograph of the plant. The terrestrial gamma exposure rates varied from about 7 to 14 microroentgens per hour at 1 meter above the ground. Protactinium-234m was observed at six sites within the boundaries of the plant. At a seventh site, only uranium-235 was observed. No other man-made, gamma ray-emitting radioactive material was present in a detectable quantity, either on ...

International Nuclear Information System (INIS)

(Jun 1972). United States Woolson, WA Las Vegas, Nev. 18 Jun 1972.

International Nuclear Information System (INIS)

Gamma-ray spectrometric analysis was employed to determine the nuclides formed in thorium by neutron irradiation. Thorium sample was irradiated by neutron from a pure thermal neutron field, neutron field of Cd ratio of about 4, and epithermal neutron field, respectively. The former irradiation was carried out in a thermal neutron column provided for medical uses of neutrons, and the latters were done in the F-ring position of TRIGA II research reactor of Musashi Institute of Technology. The gamma-ray spectra were obtained and analyzed by employing a fully automatic gamma-ray analysis system named ''GAMA: giant frog:-SYSTEM'' developped by Musashi Institute of Technology. The formation of Pa-233 (U-233) was discussed quantitatively with respect to the difference of the neutron field. (author).

Science.gov (United States)

A series of experiments is to be made during the acceptance test program of the Fast Flux Test Facility (FFTF) to measure the gamma ray characteristics of the Fast Test Reactor (FTR) and to establish the performance characteristics of the reactor shield. These measurements are a part of the FFTF Reactor Characterization Program (RCP). Detailed plans have been developed for these experiments. During the initial phase of the Characteristics Program, which will be carried out in the In-Reactor Thimble (IRT), both active and passive measurement methods will be employed to obtain as much information concerning the gamma ray environment as is practical. More limited active gamma ray measurements also will be made in the Vibration Open Test Assembly (VOTA).

International Nuclear Information System (INIS)

This paper presents the analytical results of alcohols, esters and organic acids in sweet potato wine irradiated by #gamma#-rays. (author).

Energy Technology Data Exchange (ETDEWEB)

A plutonium gamma-ray analysis system that operates on MS-DOS-based computers has been developed for the International Atomic Energy Agency (IAEA) to perform in-field analysis of plutonium gamma-ray spectra for plutonium isotopics. The program titled IAEAPU consists of three separate applications: a data-transfer application for transferring spectral data from a CICERO multichannel analyzer to a binary data file, a data-analysis application to analyze plutonium gamma-ray spectra, for plutonium isotopic ratios and weight percents of total plutonium, and a data-quality assurance application to check spectral data for proper data-acquisition setup and performance. Volume 3 contains the software listings for these applications.

Energy Technology Data Exchange (ETDEWEB)

Samples of nylon 66 rods were irradiated using a cobalt-60 gamma ray source at a dose rate of 0.25 Mrad h[sup -1] in air at room temperature to a maximum dose of 500 Mrad. The linear coefficient of thermal expansion ([alpha]) was measured using a three-terminal capacitance technique reported previously. The variation of [alpha] with temperature between 10 K and 340 K was investigated for an unirradiated sample and two samples irradiated to 300 Mrad and 500 Mrad. In the range 10K to 160K, [alpha] is almost invariant with radiation dose and there is little difference between the values for the unirradiated and the 300 Mrad irradiated samples above 160 K. The sample irradiated to 500 Mrad does show a 6% increase in [alpha] over the other samples in the higher temperature range. All samples show an increase overall in the value of [alpha] with temperature. The melting point of each sample was also determined and was shown to ...

International Nuclear Information System (INIS)

This report briefly describes the studies on the mechanism of in vivo DNA repairing by the author in Research Reactor Institute, Kyoto Univ. for the past 30 years. First, the ability of UV radiation to induce transformation was investigated with viral DNA. The formation of thymine-thymine dimer was found harmful to organisms and such dimers were removable by UV-radiation at a low frequency. The mutability was determined in three different E.coli strains with mutator gene, mutT, mutS or mutL. The ability to excise 8-oxoguanin developed in primer DNA was deficient in mutT and miss-pairing left after DNA replication could not be recovered in mutL and mutS strains. Further, DNA repairing mechanism was investigated in other microorganisms; single-strand cleavage caused by exposure to BNCB radiation (boron-neutron-captured beam) could not be repaired in E. coli. Whereas for Deinococcus radiodurans, of which survival rate was not decreased by ...

International Nuclear Information System (INIS)

The survivability of the final optic, which must sit in the line of sight of high-energy neutrons and gamma rays, is a key issue for any laser-driven inertial fusion energy (IFE) concept. Previous work has concentrated on the use of reflective optics. Here, we introduce and analyze the use of a transmissive final optic for the IFE application. Our experimental work has been conducted at a range of doses and dose rates, including those comparable to the conditions at the IFE final optic. The experimental work, in conjunction with detailed analysis, suggests that a thin, fused silica Fresnel lens may be an attractive option when used at a wavelength of 351 nm. Our measurements and molecular dynamics simulations provide convincing evidence that the radiation damage, which leads to optical absorption, not only saturates but that a 'radiation annealing' effect is observed. A system-level description is provided, including ...

International Nuclear Information System (INIS)

The absolute cross sections of "2"3Na(p,n)"2"3Mg, "2"7Al(p,n)"2"7Si and "3"0Si(#alpha#,n)"3"3S reactions were measured in the incident energy range of 5.05 to 5.80, 5.80 to 6.25 and 3.975 to 6.235 MeV respectively using a spherically shaped 4#pi# neutron detector. In the energy range 5.80 to 7.80 and 6.235 to 11.30 MeV the absolute cross sections of "2"3Na(p,n)"2"3Mg and "3"0Si-(#alpha#,n)"3"3S reactions were determined by optical model calculations. The cross sections of the inverse reactions "2"3Mg(n,p)"2"3Na and "3"3S(n,#alpha#)"3"0Si were also calculated by the same method for the neutron energy range of 10 keV to 7.50 MeV for each reaction. The cross section of the latter reaction in the neutron energy range of 10 keV to 840 keV was also determined from its inverse reaction "3"0Si(#alpha#,n)"3"3S by the application of the detailed balance theorem. The reactions for which the cross sections were determined are of importance in stellar evolution and nucleosynthesis in stars. The ...

International Nuclear Information System (INIS)

Samples of vynil-benzene and vinyl acetate were irradiated with gamma rays from a sup(60)Co source. Viscosity analysis performed by using the method of Stokes showed an increase in the viscosity of the materials up to the total solidification for increased doses of gamma rays. This result characterized the formation of macromolecules of two thermal plastics, the poly (vinyl-benzene) and the poly (vinyl acetate). (author).

International Nuclear Information System (INIS)

A time coincidence long baseline (250 km) cosmic ray detection system has been developed to search for bursts of high energy #gamma#-rays (E_0>= 10"1"3 eV) of extra-terrestrial origin. The system design incorporates the possibility of simultaneous observation over a variety of time scales between 1 #mu#s and 10 s. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

Neutron and gamma ray energy spectra were measured using an NE-213 scintillator at depths of 7.2, 15.2, and 22.2 cm in a tissue-equivalent phantom which was uniformly irradiated on one face by deuterium--tritium (DT) neutrons. Coupled neutron--gamma ray multigroup discrete-ordinates calculations were performed using semi-infinite slab geometry. These calculations were used to supplement the measured spectra below 1 MeV. Similar calculations were performed to study the perturbation in the phantom due to the detector. The measured and calculated spectra were used to determine the kerma distributions for neutrons and gamma rays at each location. The gamma radiation was determined to contribute more than 10% of the total dose at each depth. The calculated kerma also reveals that a knowledge of the gamma ray spectra below 1 ...

International Nuclear Information System (INIS)

several authors tried to drive codes to construct nuclear level scheme of nuclei using a set of measured gamma -ray transitions and known energy levels, Ritz combination principle proved to be useful in constructing a more complete decay scheme. In this thesis the energy level schemes of some nuclei have been investigated by the measurements of the gamma - ray energies and use of Ritz combination code. The nuclei under investigation are "110m Ag (253 d)"110 Cd and "166m Ho (1200 yr) "166 E r. On the basis of the suggested level at 2249.02 keV by the Ritz code new positions of the two gamma-ray transitions at 677.5 and 706.6 KeV are found in decay scheme of "110m Ag. Also by this code, new position for the 994.84 KeV gamma-ray transition were established to depopulate the level at 1075.2 KeV.

International Nuclear Information System (INIS)

M shell x-ray production cross sections in thick targets of Pb, Th and U by K x-rays of Rb, Nb and Mo respectively have been measured. As the incident K x-ray energies are above the L_3 edge but below L_2 edge energies of the respective target elements under reference, the M x-rays are produced not only due to direct interaction of incident photons with M shell electrons but also due to the shift of the L_3 subshell vacancies to the M shell. The experiment has been performed using a double reflection geometrical setup with a 1 Curie"2"4"1Am gamma ray source and a Si (Li) x-ray spectrometer. The measured values have been compared with those calculated using known values of M and L_3 subshell photoionisation cross sections and fluorescence yields etc., wherever possible. The component of the percentage contribution due to shift of L_3 subshell vacancies to M shell to the total M shell x-ray emission were evaluated and it is ...

Energy Technology Data Exchange (ETDEWEB)

In order to evaluate the effectiveness of some decontamination agents against skin contamination of {sup 60}Co and {sup 137}Cs, the experiments were carried out in this study. In the experiments, pig skin was used instead of human skin, {sup 60}CoCl{sub 2} and {sup 137}CsCl were used the liquid sources of skin contamination. To examine the effectiveness of decontamination agents, skin decontamination was tried using soup, EDTA, DAERICON which was developed for decontamination of radionuclides on the surface of building structure, and new decontamination agents such as IOCON, TRICON, and CHARCON, which were developed in this study. The absorption of radionuclides through the skin was evaluated by the gamma-ray detection on the surface of sample skin after radionuclides were penetrated into the skin during 16 hour soiling time. The results of this absorption experiment indicated that 11.5% and 3.2% of initial amounts of {sup 137}Cs and {sup 60}Co, respectively, were ...

International Nuclear Information System (INIS)

The High Flux Isotope Reactor (HFIR) located at Oak Ridge National Laboratory is one of the world's most powerful research reactors. In 1996, one year after the demise of the Advanced Neutron Source Project, the U.S. Department of Energy embarked on an aggressive program to upgrade the neutron scattering facilities at the HFIR. These upgrades, which are now in progress, include the installation of larger beam tubes, a high-performance hydrogen cold source, and additional neutron guides and neutron scattering instruments. An extensive analysis effort was performed over the past 4 yr to support the design of the modified beamlines and new user facilities and to assess the impact of the upgrades on the integrity of the existing reactor system. The results of three of these analyses are summarized here. Specifically, results are presented for analyses related to the design of the new cold neutron source (CNS), the assessment of beam tube changes on the anticipated pressure vessel lifetime, ...

Energy Technology Data Exchange (ETDEWEB)

The measurement of level in the liquid nitrogen vessel has been carried out by the weight conversion method using weigher or by putting directly a stick in the vessel. On a large CE tank, the pressure difference was read by manometer. These methods can not be used when the vessel does not put on the weigher or the pipe for manometer is stopped. We noticed the interaction between radiation ({gamma}-ray) and substance and applied it to determine the liquid nitrogen level. The results proved it the easy method for measurement of the level in the large CE tank. Cesium 137 ({gamma}-ray energy: 662 keV) was used as the radiation source. {gamma}-ray transmission dose was determined by GM survey meter. The liquid nitrogen level could be determined by using the change of the transmission dose with amount of liquid nitrogen. (S.Y.)

Energy Technology Data Exchange (ETDEWEB)

Measurements of {gamma}-ray, {gamma}{gamma}-coincidence and internal conversion electron spectra from the {sup 106}Cd({alpha},n{gamma}){sup 109}Sn reaction were carried out at 15-20 MeV {alpha}-particle bombarding energies with Ge(HP) {gamma}-ray and superconducting magnetic lens plus Si(Li) electron spectrometers. The energies, relative intensities, internal conversion coefficients and coincidence relations of the {sup 109}Sn transitions were determined, and a more complete, consistent level scheme has been deduced. Spin and parity values have been determined from the internal conversion coefficients, the bombarding-energy dependence of the side-feeding intensities of the states and the available {gamma}-ray angular distribution data. The level scheme was interpreted in the framework of the quasi-particle shell model.

Energy Technology Data Exchange (ETDEWEB)

The effects of group structures and weighting functions on neutron penetration through a thick Na-Fe geometry are studied. The recommended broad-group (61-neutron/23-gamma-ray) and few-group (22-neutron/10-gamma-ray) structures are tailored to the sodium and iron resonances, windows, and capture gamma-ray spectra. The best weighting functions are shown to be fine-group fluxes selected from a few key locations in the geometry. These group structures and weighting functions, relative to existing group structures and conventional weighting functions, improve the accuracy of the computed 61-neutron-group Bonner ball responses by up to one hundred percent and of the computed 22-neutron-group results by up to six hundred percent.

Energy Technology Data Exchange (ETDEWEB)

Fugitive dust emissions from stockpiles in the open storage yards of industrial zones and the subsequent atmospheric dust dispersion have brought about many ecological and economical problems. This paper introduces a new approach to reduce pollutant emissions by simply changing pile configuration and without affecting the operational activity on these parks. Flow around piles of different geometries and for various wind conditions was studied using previously validated Computational Fluid Dynamic (CFD) simulations. Different pile height scenarios were investigated corresponding to a constant material volume and a fixed angle of repose under various wind magnitudes. The results obtained were integrated in order to evaluate the rate of dust emissions for the various configurations considered. It was found that, for the range of wind conditions and pile dimensions tested, an optimal geometry exists which ...

Energy Technology Data Exchange (ETDEWEB)

Investigations were conducted on the range of emission rates of NO, NO[sub 2], CO and hydrocarbons, and the thermal efficiencies produced by each burner on three production cookers, supplied by different Australian manufacturers. It was found that the emissions and efficiencies were markedly affected by (1) the thermal input, both with and without a load on the burner, and (2) the load-height to flame-length ratio, with a load on the burner. The effect of hydrocarbon leakage into the secondary/dilution air was investigated, to explain the observed correlation of hydrocarbon emission rate with dilution air flow. The hydrocarbons were found to arise from two sources: -leakage from the stabilisation ports at the base of the burner, which was found to be significant at the higher thermal input; -incomplete combustion of the fuel in the premix, which was the dominant source of ...

Science.gov (United States)

A finite three-dimensional layer-by-layer photonic crystal with planar defects in a layer is shown to drastically modify the spontaneous emission rate of an embedded dipole. Finite-difference time-domain calculations with one quarter symmetric boundary condition and perfectly matched layer demonstrate the strong enhancement effects induced by the cavity resonance of defect modes and band-edge resonant modes. Simulation shows that the emission spectra are quite different when the position or polarization of the dipole is changed. Moreover, the extraction efficiency is calculated to observe the percentage of light leakage through a substrate.

Energy Technology Data Exchange (ETDEWEB)

Microcapsules consisting of alginate and hyaluronic acid that can be decomposed by radiation are currently under development. In this study, the composition of the microcapsule material was optimized by changing the amounts of alginate and hyaluronic acid. Solutions of 0.025%, 0.05%, 0.1%, 0.2%, or 0.4% (wt./vol.) hyaluronic acid were mixed into a 0.2% alginate solution. To these mixtures, carboplatin (0.2 mmol) was added and the resulting material was used for the capsule preparation. The capsules were prepared by spraying the material into a CaCl{sub 2} solution (0.34 mol/l) using a microatomizer. These capsules were irradiated by a single dose of 2, 5, or 10 Gy {sup 60}Co {gamma}-ray radiation. Immediately after irradiation, the releasing of core content of microcapsule was determined, using a micro particle induced X-ray emission (PIXE) camera. The average diameter of the microcapsules was 22.3 {+-} 3.3 {mu}m, and that of the liquid core ...

Energy Technology Data Exchange (ETDEWEB)

Proton induced X-ray and {gamma}-ray emission (PIXE/PIGE) have been used to analyze major and trace elements in a suite of 140 core samples from around of the Jim`s Find South gold anomaly in the Tanami desert, located in heavily weathered terrain. Simultaneous analyses were obtained for 30 elements, ranging in atomic number from {sup 3}Li to {sup 90}Th. The method was chosen because of its speed and the wide range of determination, its flexibility, precision and low detection limits. The regolith powder samples were treated by hot aqua regia before making them into pills. The PIXE/PIGE data of the acid insoluble residue give three factor analysis clusters. The first cluster comprises the elements F, Al, K, V, Mn, Fe, Ga, Rb, W and Au and is essentially related to sericitic wallrock alteration. The second cluster consists of Ti, As, Y, Zr, and Nb and is largely related to resistant minerals. The third cluster consists of Na, Ca and Sr and is ...

Energy Technology Data Exchange (ETDEWEB)

In large samples, the {gamma}-ray count rate of a prompt gamma neutron activation analysis system is a multi-variable function of the elemental dry composition, density, water content and thickness of the material. The experimental calibration curves require tremendous laboratory work, using a great number of standards with well-known compositions. Although a Monte Carlo simulation study does not avoid the experimental calibration work, it reduces the number of experimental calibration standards. This paper is part of a feasibility study for a PGNAA system for on-line continuous characterisation of cement raw material conveyed on a belt (Oliveira, C., Salgado, J. and Carvalho, F. G. (1997) Optimisation of PGNAA instrument design for cement raw materials using the MCNP code. J. Radioanal. Nucl. Chem. 216(2), 191-198; Oliveira, C., Salgado, J., Goncalves, I. F., Carvalho, F. G. and Leitao, F. (1997a) A Monte Carlo study of the influence of ...

International Nuclear Information System (INIS)

The radioactive decay of "2"0"3Bi is studied. A level scheme is proposed for "2"0"3Pb on the basis of #gamma#-ray and electron spectra and #gamma#-#gamma# coincidence measurements. The experimental data are compared with theoretical results obtained in a three quasiparticle approximation. (Auth.).

International Nuclear Information System (INIS)

Detailed level and decay schemes and the experimental reaction and decay data on which they are based are presented for nuclei with mass number A = 242; the experimental data are evaluated. Adopted values for level and #gamma#-ray energies, #gamma#-intensities, as well as other nuclear properties are given.

International Nuclear Information System (INIS)

Several configurations of moderating and shielding materials have been designed and measured on the LVR-15 reactor for boron neutron capture therapy (BNCT) purposes. To determine the neutron and gamma ray space-energy distributions in the cylindrical geometry, the two-dimensional code DOT with the coupled neutron-gamma data library DLC-36 was used. The experimental verification of the beam parameters was performed in the LVR-15 reactor thermal column empty space with layers of graphite, aluminium, alumina, lead and bismuth. Attention was paid to establishing techniques and instrumentation for monitoring the neutron and gamma ray dose and beam quality. The thermal and epithermal flux densities were measured by activation foils, the neutron spectrum was determined with a Bonner spectrometer and gamma ray background with a scintillation spectrometer. The ...

International Nuclear Information System (INIS)

Reliable values of x-ray and gamma-ray attenuation coefficients of elements and compounds are required in spectrometry as well as in many other scientific, engineering and medical disciplines involving photon radiation

International Nuclear Information System (INIS)

Bulgarian ... Orig. Title Vliyanie na gama-lychite vyrkhu spirokheti ot vida Borrelia anserina, Sakharoff, 1891. Chast 2. Promeni v antigenniya stroezh.

Energy Technology Data Exchange (ETDEWEB)

An analyser for detecting explosives has at least one neutron source and a plurality of gamma ray detectors. An article to be analysed is moved adjacent the source and detectors and is subjected to neutrons which generate gamma rays from any nitrogen in the article. The gamma rays are detected and analysed to determine the nitrogen concentration within the article. In order to achieve an area of uniform detection there are a plurality of detectors equidistant both from the or each source and from the article to be analysed. In order to avoid a decrease in sensitivity away from the source(s) and detectors there may be a second opposing array of source(s) and detectors on the opposite side of the article. For greatest uniformity of detection, a source in one array opposes a detector in the other array and vice versa. Transmission of radiation from the analyser is ...

Science.gov (United States)

Probing Neutron Star Evolution with Gamma Rays Online Source: Click to View PDF File [PDF Size: 217 KB] Author: Wijers, Ralph A. M. J. ...

DEFF Research Database (Denmark)

The objectives of this study were to characterize the changes of VOC material emission profiles over time and develop a method to account for such changes in order to enhance a source identification technique that is based on the measurements of mixed air samples and the emission signatures of individual building materials determined by PTRMS. Source models, including powerlaw model, doubleexponential decay model and mechanistic diffusion model, were employed to track the change of individual material emission signatures by PTRMS over a ninemonth period. Samples of nine typical building materials were tested individually for nine months and later in combination to obtain actual mixture emissions. VOC emissions from each material were measured in a 50liter smallscale chamber. Chamber air was sampled by PTRMS over a 28day period to determine their emission ...

Energy Technology Data Exchange (ETDEWEB)

Natural radioactivity found in rocks and its evaluation been frequently used for studies of environmental geochemistry, particularly those of detection and control of pollutants and the consequent changes in environment after antropic interferences. In this work natural radioactivity in forty nine soil samples in the basin of Buquira river, at the Northeast region of Sao Paulo State, has been analysed and measured with a Ge-HP gamma ray spectrometer. A table with the most relevant results found in rocks is shown and discussed. (author)

International Nuclear Information System (INIS)

Two experiments are currently underway to measure the single-particle weak mixing matrix element for the 1064 KeV transition in "2"0"7Pb. One experiment measures the circular polarization of the 1064 KeV gamma ray emitted from an unpolarized source, while the other experiment measures the forward-backward asymmetry of gamma rays emitted from a polarized source. Analysis of the first set of polarized source data yields an upper limit of 46 eV for the single-particle weak mixing matrix element. copyright 1995 American Institute of Physics.

Energy Technology Data Exchange (ETDEWEB)

Energy conservation and local energy deposition are investigated in the context of coupled-particle (i.e., neutrons, gamma rays, and charged particles) transport analysis. For charged particles, the concept of group splitting the 1 = 0 transfer matrix to ensure both particle and energy conservation is introduced. Although these procedures are more complex than those found in the usual neutron or coupled-neutron gamma-ray problem, they yield a consistent approach for the calculation of local energy deposition.

Energy Technology Data Exchange (ETDEWEB)

The proposed short wavelength coherent light source driven by the SLAC 3 km linac might be used to induce transitions between nuclear isomeric states. If an isotope were found with energetically adjacent isomeric states, one short-lived and one long-lived, and it were possible to separate and concentrate the long-lived species, and other nuclear and solid-state parameters were favorable, it might be possible to convert sufficient population to the short-lived state to realize [gamma]-ray lasing. Even if the x-ray intensity were insufficient, study of such driven transitions would be quite valuable.

Energy Technology Data Exchange (ETDEWEB)

DOE/NNSA and IRSN collaborated on a study of gamma-ray instruments and analysis methods used to perform isotopic measurements of special nuclear materials. The two agencies agreed to collaborate on the project in response to inconsistencies that were found in the various versions of software and hardware used to determine the isotopic abundances of uranium and plutonium. IRSN used software developed internally to test the MGA and FRAM isotopic analysis codes for criteria used to stop data acquisition. The stop-criterion test revealed several unusual behaviors in both the MGA and FRAM software codes.

International Nuclear Information System (INIS)

There is an urgent need to improve the reliability of screening cargo containers for illicit nuclear material that may be hidden there for terrorist purposes. A screening system is described for detection of fissionable material hidden in maritime cargo containers. The system makes use of a low intensity neutron beam for producing fission; and the detection of the abundant high-energy #gamma# rays emitted in the #beta#-decay of short-lived fission products and #beta#-delayed neutrons. The abundance of the delayed #gamma# rays is almost an order of magnitude larger than that of the delayed neutrons normally used to detect fission and they are emitted on about the same time scale as the delayed neutrons, i.e., #approx#1 min. The energy and temporal distributions of the delayed #gamma# rays provide a unique signature of fission. Because of their high energy, these ...

CERN Document Server

Neutrino emission drives neutron star cooling for the first several hundreds of years after its birth. Given the low energy ($\\sim$ keV) nature of this process, one expects very few nonstandard particle physics contributions which could affect this rate. Requiring that any new physics contributions involve light degrees of freedom, one of the likely candidates which can affect the cooling process would be a nonzero magnetic moment for the neutrino. To illustrate, we compute the emission rate for neutrino pair bremsstrahlung in neutron-neutron scattering through photon-neutrino magnetic moment coupling. We also present analogous differential rates for neutrino scattering off nucleons and electrons that determine neutrino opacities in supernovae. Employing current upper bounds from collider experiments on the tau magnetic moment, we find that the neutrino ...

Energy Technology Data Exchange (ETDEWEB)

There are two types of ionization chamber using magnetically levitated electrode: one is that by Tanaka et al. and the other, by authors'. The latter lacks the sensitivity relative to the former and thereby to solve the problem, authors made an improvement so that the electrode charge could be readout by noncontact after the leviated electrode was electrified by noncontact for an interval. This new type ionization chamber made it possible to measure the quite low dose radiation with stability and high sensitivity. Actually, the electrode was suspended by the teflon thread fixed on the steel cup levitated magnetically in the ionization chamber of which wall was covered by Al and equipped with an electrostatic charger for the electrode by noncontact. After measurement, the electrode was moved in the Faraday cage placed under the chamber to readout the voltage. For operation conditions of the apparatus, observation was done on the relationship between ionization current by {sup ...

International Nuclear Information System (INIS)

Apricot fruits usually harvested relatively mature but hard enough to withstand-post harvest handling through the marketing chain. These fruits have considerably lower edible quality than tree-ripened fruit. Fruit quality can be improved by delaying harvest least until physiological maturation is completed on the tree (Bonghi et al. 1999) Apricots containing 11% soluble solids concentration, or higher are in high demand by consumers, as fruit have developed considerable taste, aroma and handling for long distance markets. (Kader, 1999). These fruit will be highly perishable, so rapid cold storage to the lowest safe temperature and supplementary treatments (Mc Donald et al, 1999) such as irradiation with the recommend doses (Sillano et al, 1994) or pre-storage heat treatments will be necessary to retard ripening (mainly softening) during 1-2 weeks post harvest life necessary for distribution to distant markets (Mc Donald et al 1999). Therefore, one can conclude that spraying Canino ...

Energy Technology Data Exchange (ETDEWEB)

Two neutron emesis experiments were conducted at the Armed Forces Radiobiology Research Institute (AFRRI). In both experiments (described as Phase I and Phase II) the radiation dose required to cause emesis in 50% of subjects (ED50) was determined for both neutron reactor and gamma reactor source radiation. Emesis onset, offset and duration times post-exposure are reported. Neutrons were maximized from the reactor by passing the beam through a 15.25 cm (6 in.) thick lead wall to filter out gamma photons. Gamma rays were maximized by thermalizing neutrons in 30.5 cm (12 in.) of water, then absorbing the thermal neutrons in a gadolinium-cadmium shield. In Phase I, 28 dogs were exposed to radiation: 12 were exposed to gamma photons at the rate of 0.69 Gy/min and 16 were exposed to neutrons at 1.2 Gy/min. In Phase II, 58 dogs in 3 groups were exposed to radiation: 19 were exposed in the gamma group at 0.75 Gy/min, 20 were ...

International Nuclear Information System (INIS)

A next generation e"+-e"- linear collider in the TeV range can be converted into a #gamma#-#gamma# collider by converting it to e"--e"- operation and then generating #gamma#-rays via Compton backscattering with optical beams. This provides unique access to some areas of fundamental physics as well as highly desirable redundancy to the collisions. The required optical beam (with a wavelength of about 1 micron) must have very high peak power, (about 1 TW) as well as average power (about 10 kW). To achieve a 1 : 1 conversion from an electron to #gamma#-quantum, each micropulse must contain about one Joule and must be about one picosecond long, the micropulse peak power being about one Terawatt. To match the electron beam pulse structure, a macropulse consists of a sequence of about one hundred micropulses separated by about one nanosecond, and the macropulses am repeated at a rate of about 100 Hz. Thus, the time average power is about 10 kW ...

Energy Technology Data Exchange (ETDEWEB)

For Stage II of the European Dioxin Project the following objectives were set: - Amendment of existing emission data collected for most relevant emission sources in order to reduce uncertainties of emission estimates. Collecting first emission data from countries not yet performing dioxin emission measurement programs. Extending the inventory of dioxin emissions to ambient air produced in Stage I by a complementary study on emissions to land and water. Extending the regional scope of data collection to countries in Central Europe. The report of Stage II of the European Dioxin Project is presented in 3 Volumes. Volume 1 contains an overview on the background and approach of different activities carried out and on the results obtained. These results are put into a broader view regarding the dioxin reduction measures in Europe leading to ...

CERN Document Server

The problem of spectra formation in hydrodynamic approach to A+A collisions is discussed. It is analyzed in terms of the two different objects: distribution and emission functions. We show that though the process of particle liberation, described by the emission function, is, usually, continuous in time, the observable spectra can be also expressed by means of the Landau/Cooper-Frye prescription. We argue that such an approximate duality results from some symmetry properties that systems in A+A collisions reach to the end of hydrodynamic evolution and reduction of the collision rate at post hydrodynamic stage

International Nuclear Information System (INIS)

Heavy-duty trucks and buses are substantial contributors to the atmospheric oxides of nitrogen (NO_x) inventory, but prediction of their emissions in real use remains inchoate. Continuous emissions of NO_x were recorded from Chassis dynamometer testing of eight vehicles using a variety of transient cycles, including the Central Business District schedule. NO_x data were treated to account for sampling time lag and presented against instantaneous vehicle axle power. Data were repeatable from run to run and test schedule, but vehicle type and test cycle both influenced the instantaneous emissions rates. However, the resulting correlations may be used for mobile source NO_x contribution estimation when combined with vehicle activity data. The emissions data were also presented as NO_x/CO_2, which are valuable for comparison with remote sensing emissions data. The ...

Energy Technology Data Exchange (ETDEWEB)

Personnel radiation monitoring is essential to the operation of any nuclear facility and work in this area continues to strive for an accurate determination of personnel dose. In particular recent attention has been focused upon the need to improve the accuracy of neutron dosimetry, mainly because of their high Relative Biological Effectiveness. In this work the feasibility of using the NE-213 liquid scintillation detector as an efficient neutron/..gamma.. ray radiation monitor is demonstrated. Derivative method spectrum unfolding used in MATXUF for on-line analysis of fast neutron spectra has also been applied to real time ..gamma.. spectrum unfolding (MATXUF2), making possible simultaneous on-line monitoring of both fast neutrons and gammas. To eliminate the negative fluxes in the unfolded ..gamma.. spectra created by the photopeak-Compton edge combination in the plateau portion of the knee response, correcting equations using a linearized ...

Science.gov (United States)

Personnel radiation monitoring is essential to the operation of any nuclear facility and work in this area continues to strive for an accurate determination of personnel dose. In particular recent attention has been focused upon the need to improve the accuracy of neutron dosimetry, mainly because of their high Relative Biological Effectiveness. In this work the feasibility of using the NE-213 liquid scintillation detector as an efficient neutron/gamma ray radiation monitor is demonstrated. Derivative method spectrum unfolding used in MATXUF for on-line analysis of fast neutron spectra has also been applied to real time gamma spectrum unfolding (MATXUF2), making possible simultaneous on-line monitoring of both fast neutrons and gammas. To eliminate the negative fluxes in the unfolded gamma spectra created by the photopeak-compton edge combination in the plateau portion of the knee response, correcting equations using a linearized approximation ...

British Library Electronic Table of Contents (United Kingdom)

Carbon monoxide (CO) and carbon dioxide (CO2) emissions during a spontaneous heating event in a coal mine are important gases to monitor for detecting the spontaneous heating at an early stage. However, in underground coal mines, the CO and CO2 concentrations and their related fire ratios may be affected by mine ventilation. In this study, CO and CO2 emissions from spontaneous heating of a U.S. coal sample were evaluated in an isothermal oven under different airflow ventilation rates ranging from 100 to 500cm^3/min. Laboratory experiments were conducted at oven temperatures of 70, 90, and 100^oC. The temperature at the center of the coal sample was continually monitored, while the CO, CO2, and oxygen (O2) concentrations of the exit gas were continually measured. The results indicate that C...

Energy Technology Data Exchange (ETDEWEB)

A gamma-ray spectrometer (GRS) has been built and delivered to the Mercury MESSENGER spacecraft which launched on August 3, 2004, from Cape Canaveral, Florida. The GRS, a part of seven scientific instruments on board MESSENGER, is based on a coaxial high-purity germanium detector. Gamma-ray detectors based on germanium have the advantage of providing excellent energy resolution, which is critical to achieving the science goals of the mission. However, germanium has the disadvantage that it must operate at cryogenic temperatures (typically {approx}80 K). This requirement is easy to satisfy in the laboratory but difficult near Mercury, which has an extremely hot thermal radiation environment. To cool the detector, a Stirling cycle mechanical cooler is employed. In addition, radiation and conduction techniques a are used to reduce the GRS heat load. Before delivering the flight sensor, a complete thermal prototype was built and tested. The results ...

CERN Document Server

The bright gamma-ray burst GRB050525a has been detected with the Swift observatory, providing unique multiwavelength coverage from the very earliest phases of the burst. The X-ray and optical/UV afterglow decay light curves both exhibit a steeper slope ~0.15 days after the burst, indicative of a jet break. The timing of the jet break combined with the total gamma-ray energy of the burst constrains the opening angle of the jet to be 2.5 degrees. We derive an empirical `time-lag' redshift from the BAT data of z_hat = 0.69 +/- 0.02, in good agreement with the spectroscopic redshift of 0.61. Prior to the jet break, the X-ray data can be modelled by a simple power law with index alpha = -1.2. However after 300s the X-ray flux brightens by about 30% compared to the power-law fit. The optical/UV data have a more complex decay, with evidence of a rapidly falling reverse shock component that dominates in the first minute or so, giving way to a flatter ...

International Nuclear Information System (INIS)

In conducting aircraft surveys for uranium, it is found that temperature inversions can give spurious results because they promote accumulation of radon gas in the atmosphere. The "2"1"4Bi (daughter product of radon) gamma-rays detected from the atmosphere-borne radon are difficult to separate from the "2"1"4Bi gamma-rays originating from the ground, and providing a signature for uranium deposits. The purpose of the present study was to examine the feasibility of making remote temperature soundings of the atmosphere below a low-flying aircraft (140 m or less above ground) by the inversion of radiance measurements taken in the 15-micron carbon dioxide absorption band. Such measurements would identify those temperature inversion conditions possibly leading to an unacceptably large background of gamma-rays from the atmospheric radon. Thus, the incidence of spurious aerial survey data could be greatly reduced. An atmospheric ...

CERN Document Server

AMS is a particle detector designed to perform high precision measurements of the cosmic rays fluxes with the main goals of searching for anti-nuclei, as remnants of primordial anti-matter, and of measuring the faintest components of the cosmic flux, anti- protons, positrons and high energy photons. To fulfill the requirements of large acceptance, long exposure time and excellent particle identification needed to achieve the intended results, AMS will operate in space as an attached payload to the International Space Station (ISS), being the first full featured particle physics experiment to operate in the Earth orbit. The AMS-02 accurate measurements of cosmic-ray nuclei, protons, antiprotons, electrons and positrons will be completed by high energy gamma rays detection. The experiment will detect gamma-rays, either by reconstructing e+e? pairs generated by photons converted upstream the tracker (conversion mode), or based ...

International Nuclear Information System (INIS)

A programme has been initiated by the Coordinating Office for Monitoring of enhanced natural radioactivity of the Federal Office for Radiation Protection to investigate different kinds of sample materials with enhanced naturally occurring radioactivity (NORM) such as scales from oilfield and naturally gasfield pipes, blast furnace sludge and sinter dust from the production of pig iron, as well as bauxit and red mud from the production of aluminium oxide. The aim of these investigations is to find proper preparation and measuring methods which allow, in particular, a sample treatment with optimised effort combined with a reliable determination of the specific activities of the dominating radionuclides. Of particular interest is the method of gamma-ray spectrometry, since this method has been used for most of our studies of sample materials. Due to different compositions of calibration and NORM-samples, e.g. different densities, and the analysis of low-energy ...

Energy Technology Data Exchange (ETDEWEB)

Yet designed to measure charged component of the cosmic rays, the foreseen Alpha Magnetic Spectrometer (AMS-02) could also release {gamma}-ray studies, in the energy range from GeV to TeV, using the tracker system, for {gamma}-rays converted in e{sup +}e{sup -} pair, and the electromagnetic calorimeter. In the first part of the thesis are described the calibrations and the performances of the engineering model of the calorimeter, obtained from the analysis of data taken during a test-beam performed at CERN in July 2002. In the second part of the thesis, the AMS-02 discovery potential for {gamma}-astrophysics is presented. While exposure maps of the {gamma}--sky are computed for one year of data taking with the {gamma}--detectors, the acceptance of the calorimeter is obtained from Monte-Carlo simulations. The AMS-02 potential is then estimated for signals from the Vela pulsar and for some supersymmetric signals from the Galactic Center. (author)

CERN Document Server

Gamma-Ray Bursts (GRBs) are thought to originate at cosmological distances from the most powerful explosions in the Universe. If GRBs are not beamed then the distribution of their number as a function of gamma-ray flux implies that they occur once per (0.3-40) million years per bright galaxy and that they deposit >10^{53} ergs into their surrounding interstellar medium. The blast wave generated by a GRB explosion would be washed out by interstellar turbulence only after tens of millions of years when it finally slows down to a velocity of 10 km/s. This rather long lifetime implies that there could be up to several tens of active GRB remnants in each galaxy at any given time. For many years, radio observations have revealed the enigmatic presence of expanding neutral-hydrogen (HI) supershells of kpc radius in the Milky Way and in other nearby galaxies. The properties of some supershells cannot be easily explained in terms of conventional ...

Energy Technology Data Exchange (ETDEWEB)

Methane (CH{sub 4}) produced microbially in sediments of marshes is emitted to the atmosphere primarily by flowing through and out of emergent aquatic plants. The magnitude of such emission rates and factors controlling those rates are not well understood. We evaluated CH{sub 4} emission from the widely distributed aquatic emergent plant cattail (Typha latifolia L.) in several wetlands in the United States using a field gas-exchange system that concurrently estimated stomatal aperture (i.e., conductance) on the surface of leaves and net photosynthesis. We compared gas exchange among plants of different age and from sites with different soil and atmospheric conditions. The mean rate of CH{sub 4} emission was 0.22{mu}mol m{sup -2} [leaf] s{sup -1}, which is 940 mg CH{sub 4} m{sup -2} d{sup -1} on a ground-area basis, with individual rates ...

Energy Technology Data Exchange (ETDEWEB)

We estimate the TeV {gamma}-ray fluxes expected from the population of young pulsars in terms of the self-consistent time-dependent hadronic-leptonic model for the high-energy processes inside the pulsar wind nebulae (PWNe). This radiation model is based on the hypothesis of Arons and collaborators who postulate that leptons are accelerated inside the nebulae as a result of resonant scattering on heavy nuclei, which in turn are accelerated in the pulsar wind region or the pulsar inner magnetosphere. Our aim is to find out which PWNe on the northern hemisphere are the best candidates for detection at energies above 60 GeV and 200 GeV by the next generation of low-threshold Cherenkov telescopes.

International Nuclear Information System (INIS)

A new structure of GaAs MESFET with high radiation tolerance is proposed. Changes in electrical parameters of a GaAs MESFET as a function of total #gamma#-ray dose have been found to be caused mainly by a decrease in the effective carrier concentration in an active layer. The authors have designed a new structure from a simulation based on an empirical relationship between the changes of the effective carrier concentration and the total #gamma#-ray dose. It has been successfully demonstrated by utilizing a highly-doped thin active layer (4 x 10"1"8 cm"-"3, 100 Angstrom) grown by OMVPE. This MESFET can withstand a dose ten times higher [1 x 10"9 rads(GaAs)] than a conventional one can.

Energy Technology Data Exchange (ETDEWEB)

We studied the effects of small, <20 {micro}m, Te inclusions on the energy resolution of CdZnTe gamma-ray detectors using a highly collimated X-ray beam and gamma-rays, and modeled them via a simplified geometrical approach. Previous reports demonstrated that Te inclusions of about a few microns in diameter degraded the charge-transport properties and uniformity of CdZnTe detectors. The goal of this work was to understand the extent to which randomly distributed Te-rich inclusions affect the energy resolution of CZT detectors, and to define new steps to overcome their deleterious effects. We used a phenomenological model, which depends on several adjustable parameters, to reproduce the experimentally measured effects of inclusions on energy resolution. We also were able to hound the materials-related problem and predict the enhancement in performance expected by reducing the size and number of Te inclusions within the crystals.

CERN Document Server

Dark Matter annihilation (DMA) may yield an excess of gamma rays and antimatter particles, like antiprotons and positrons, above the background from cosmic ray interactions. The excess of diffuse Galactic Gamma Rays from EGRET shows all the features expected from DMA. The new precise measurements of the antiproton and positron fractions from PAMELA are compared with the EGRET excess. It is shown that the charged particles are strongly dependent on the propagation model used. The usual propagation models with isotropic propagation models are incompatible with the recently observed convection in our Galaxy. Convection leads to an order of magnitude uncertainty in the yield of charged particles from DMA, since even a rather small convection will let drift the charged particles in the halo to outer space. It is shown that such anisotropic propagation models including convection prefer a contribution from ...

CERN Document Server

This paper presents a review of the history, motivation and current status of high energy neutrino telescopes. Many years after these detectors were first conceived, the operation of kilometer-cubed scale detectors is finally on the horizon at both the South Pole and in the Mediterranean Sea. These new detectors will perhaps provide us the first view of high energy astrophysical objects with a new messenger particle and provide us with our first real glimpse of the distant universe at energies above those accessible by gamma-ray instruments. Some of the topics that can be addressed by these new instruments include the origin of cosmic rays, the nature of dark matter, and the mechanisms at work in high energy astrophysical objects such as gamma-ray bursts, active galactic nuclei, pulsar wind nebula and supernova remnants.

International Nuclear Information System (INIS)

Excited states in the T_z=(1/2) nucleus "8"5Mo have been observed for the first time with the reaction "5"8Ni("3"2S,#alpha#n#gamma#) at 105 MeV. #gamma#-ray transitions in this nucleus have been assigned unambiguously by combining the information from the GASP #gamma#-ray array, the ISIS silicon ball, and the n-Ring neutron detector. Two band structures have been observed in this nucleus; they continue the smooth evolution of the known bands from the lighter N=43 isotones and have been tentatively assigned spins and parity on this basis. After reaching a maximum of collectivity at "8"3Zr, the trend with increasing mass is reversed, showing a smaller collectivity at "8"5Mo. The rotational behavior of the observed bands is discussed on the basis of the projected shell model calculations.

International Nuclear Information System (INIS)

Neutron capture #gamma#-ray spectra have been measured at 11 average neutron energies from 10 to 530 keV in /sup 88/Sr using a 20 x 15 cm NaI detector with time-of-flight discrimination of background events. The partial radiation widths and the calculated partial valence widths are compared for the strong p-wave resonances at 287 and 321 keV and found to be highly correlated. At these energies, the spectra are dominated by strong transitions to low-lying single particle states, in confirmation of the role of valence capture in the 3p region. However, the data do not support this mechanism at <508> keV.

International Nuclear Information System (INIS)

The effect of exposure to gamma rays on LPO contents in liver, spleen and kidney of mice and the anti-lipid-peroxidation of preparations of chinonin, tannic acid and squalene were reported. All these preparations were given by intragastric perfusion. For LPO, a modified method of TBA spectrophotometry was used for determination. The results show that LPO contents in tissues increased 72 h after whole-body exposure of mice to gamma rays, that in range of 0-4 Gy, there was a linear relationship between radiation doses and LPO contents, and that all three preparations were effective in reduction of the LPO content in liver, spleen and kidney of mice, with chinonin (at dose of 0.35 mg/mouse#centre dot#day) being more effective than tannic acid (at dose of 15 mg/mouse#centre dot#day) and squalene (at dose of 0.6 mg/mouse#centre dot#day).

International Nuclear Information System (INIS)

Recently, foods are often exposed to radiation under packed states with various wrapping materials. In this study, the effects of #gamma#-ray radiation were investigated on the additives in wrapping materials on the market. 10 - 50 kGy #gamma# radiation was irradiated to samples under sealed condition in a glass-ware. Polyethylene bag and wrapping film, polypropylene wrapping film, cup and sheet, and polystyrene cup were used as samples. And the additives in these materials were analyzed by GC/MS to evaluate the radiation effects on them. The irradiation was found to induce rapid degradation of antioxidants, especially, Irgafos 168. Some fatty acid amides used as a lubricant and a plasticizer, DBP were also reduced, but not aliphatic hydrocarbons. However, all polystyrene products used in this study included no additives. The contents of styrene dimer and trimer in those wrapping materials were not changed by #gamma#-irradiation. (M.N.)

Energy Technology Data Exchange (ETDEWEB)

The alpha particle induced fission of {sup 209}Bi has been investigated for E{sub {alpha}} = 55.7 and 58.6 MeV using gamma ray spectrometry. The cross sections for the production of fission products have been determined. The mass distributions have been found to be broad with a peak near mass 104. The charge distribution has been studied at the same particle energies. The fractional cumulative yields of {sup 97}Zr, {sup 99}Mo, {sup 101}Mo, {sup 112}Pd and {sup 117m}Cd have been determined using gamma ray spectrometry. The width of charge distribution is broad. (orig.).

International Nuclear Information System (INIS)

Since the commissioning of the first 10 strings of the AMANDA neutrino telescope, more than nine years of data has been collected. The proof of principle of high-energy neutrino detection in ice is established. No positive signal of an extra-terrestrial high-energy neutrino flux have been found so far. However, the most stringent upper limits to the flux of cosmic neutrinos-respectively, diffuse, point like or associated with gamma-ray bursts-have been presented. A sample of 3329 up-going muon tracks, representing the largest statistics ever of high-energy neutrino induced events, has been collected between 2000 and 2003. A coincidence of neutrino with an anomalous high-energy gamma-ray flare has been observed from the direction of the Blazar 1ES1959+650-although the observation were not conclusive. Selected results of data taken with the AMANDA detector are here reported.

International Nuclear Information System (INIS)

A large area Bragg curve spectroscopy (BCS) detector and a position sensitive parallel grid avalanche counter have been developed to study heavy ion reactions, such as inelastic excitations and few nucleon transfer reactions near the Coulomb barrier. Reasonably good resolutions have been achieved for energy, atomic number and angle. A theoretical investigation on the mass dependence of the Bragg peak signal from the BCS detector, shows that there is a negligible mass dependence related to the geometry of the detector. The mass number of the heavy ions which cannot be obtained by the above method, has been identified by detecting the corresponding characteristic gamma rays from the product nuclei with two large solid angle gamma ray detectors. (orig.).

International Nuclear Information System (INIS)

This paper deals with estimating aircraft landing and take-off (LTO) emissions (HC, CO, NO_x, SO_2) at 40 Turkish airports including the biggest airports, i.e. Ataturk International Airport (AIA) in Istanbul, Antalya Airport in Antalya and Esenboga Airport in Ankara in 2001. The calculation model is based on flight data recorded by the State Airports Authority. The flight data include the type and number of aircraft, number of passengers, amount of cargo etc., which depend on day-time and date. For the emission calculations the International Civil Aviation Organization (ICAO)-Engine emission data bank, which includes minimum and maximum values for both fuel flow rates and emissions factors, is used. By using first the minimum and then the maximum values from the data bank, two estimations of aircraft LTO emissions at Turkish airports are calculated: i.e. minimum ...

Energy Technology Data Exchange (ETDEWEB)

The radionuclide characteristics of light-water-reactor (LWR) spent fuel play key roles in the design and licensing activities for radioactive waste transportation systems, interim storage facilities, and the final repository site. Several areas of analysis require detailed information concerning the time-dependent behavior of radioactive nuclides including (1) neutron/gamma-ray sources for shielding studies, (2) fissile/absorber concentrations for criticality safety determinations, (3) residual decay heat predictions for thermal considerations, and (4) curie and/or radiological toxicity levels for materials assumed to be released into the ground/environment after long periods of time. The crucial nature of the radionuclide predictions over both short and long periods of time has resulted in an increased emphasis on thorough validation for radionuclide generation/depletion codes. Current radionuclide generation/depletion codes have the capability to follow the ...

International Nuclear Information System (INIS)

Data of thermally stimulated luminescence (TSL) of single (Cu), double (Cu, Mn) and triple (Cu, Mn, Gd) activated SrS phosphors, which throws light on the nature and distribution of deeper traps have been presented. The samples are prepared by Bhawalkar's method and excited by UV 365 nm and #gamma#-rays to study the phenomenon. (author). 8 refs., 2 figs., 1 tab.

Energy Technology Data Exchange (ETDEWEB)

High-spin states in {sup 202}Pb and {sup 203}Pb have been investigated by in-beam {gamma}-ray spectroscopy following the reaction {sup 198}Pt({sup 9}Be,xn). A search for magnetic rotational bands in these isotopes confirmed one of the two bands previously assigned to {sup 202}Pb and revealed a new band in this isotope. No evidence for magnetic rotation has been found in {sup 203}Pb. (orig.)

DEFF Research Database (Denmark)

In 1995 the exercise RESUME-95 (Rapid Environmental Surveying Using Mobile Equipment) took place in Finland. Groups from 8 European countries joined the exercise. The methods used were airborne gamma-ray measurements, car-borne measurements and in situ stationary measurements. The results of the measurements are analyses aiming at disclosing similarities and differences between groups and measuring techniques.

International Nuclear Information System (INIS)

This review briefly describes current efforts to develop superradiant sources of coherent radiation for the sub-nanometer range of wavelenghs, using nuclear rather than the atomic or molecular transitions that are stimulated in existing lasers. First the radiative (including Raman) interactions of nuclei with those of atoms and molecules are compared; then the present status of research on the fundamental problems involved in stimulating nuclear gamma radiation is described. (author). 20 refs.; 2 figs.

International Nuclear Information System (INIS)

Detailed level schemes, decay schemes, and the experimental data on which they are based are presented for all nuclei with mass numbers A -- 216, 220, 224, and 228. The experimental data are evaluated; inconsistencies and discrepancies are noted; and adopted values for level and #gamma#-ray energies, #gamma# intensities, as well as for other nuclear properties are given.

International Nuclear Information System (INIS)

Juvenile trees of kalmia derived from shoot tip culture, and seedlings of kobus were irradiated with #gamma#-rays. In kalmia, two mutation lines were obtained which had narrowlong leaves. In kobus two mutation lines were obtained. One mutation line has flowers with 7 to 13 petals. Another mutation line has yellow-green variegated leaves. (author).

International Nuclear Information System (INIS)

The gamma scanning system which is installed in IMEF is the equipment obtaining the gamma ray spectrum from irradiated fuels. This equipment could afford the useful data relating spent fuels like as burn-up measurements. We describe the specifications of the equipment and its accessories, and also described its operation procedure so that an operator can use this report as the operation procedure. (author). 1 tab., 11 figs., 11 refs.

Energy Technology Data Exchange (ETDEWEB)

Natural radioactive materials were used for detector calibration. We found that KCl is a very suitable material for this purpose. The efficiency curve shape was derived by using {gamma} ray lines of {sup 214}Bi normalised using a known quantity of KCl in the same geometry. The best fit was found by the least squares method. The summing correction coefficients for {sup 214}Bi are determined. (orig.).

Science.gov (United States)

Thesis. Five-particle shell-model calculations, using a spin-dependent potential, were performed for the nucleus /sup 101/Tc. The effects of varying the single-particle energy differences and the strengths of the spin-dependent and pairing terms are discussed. The isobars /sup 101/Mo and /sup 101/Tc were chemically separated to enable the detailed study of their decay schemes. As a result, 184 gamma rays were observed in the decay of /sup 101/Mo, and 169 of them were assigned to 45 levels in /sup 101/Tc. In the decay of /sup 101/Tc, 27 gamma rays were observed, and 26 of them were assigned to 11 levels in /sup 101/Ru. In a study of the decays of /sup 142/Xe and /sup 142/Cs the TRI STAN on-line isotope separator was used to separate the 142 mass chain produced in /sup 235/U fission with /sup 142/2Xe as the emanating and accelerated nuclide. Isobaric separation of /sup ...

International Nuclear Information System (INIS)

The crabbing of an incident photon beam from a laser, and the electron beam with which it interacts at the conversion point, is shown to have the same efficiency as in head-on Compton scattering, but with the advantages of a crossing geometry. The resulting #gamma#-ray beam is also crabbed, which allows for a crossing collision point, while maintaining the luminosity at the same value it would have in a head-on collision.

International Nuclear Information System (INIS)

The crabbing of an incident photon beam from a laser, and the electron beam with which it interacts at the conversion point, is shown to have the same efficiency as in head-on Compton scattering, but with the advantages of a crossing geometry. The resulting #gamma#-ray beam is also crabbed, which allows for a crossing collision point, while maintaining the luminosity at the same value it would have in a head-on collision. ((orig.)).

International Nuclear Information System (INIS)

We studied the solvent extraction behavior of astatine and found the anomalous behavior of this element similar to radioiodine. Astatine was extracted into CS_2 from acidic solution over a wide range of carrier iodine concentration. The distribution ratios of astatine were determined by measuring the #gamma#-ray from 210 At with a NaI(Tl) detector. A drastic change was observed around at 10"-"4 mol/l as in the case of 131 l. This tendency is well explained by the kinematics of the chemical reactions concerned. (author).

International Nuclear Information System (INIS)

A comparison of maximum likelihood (or chi-square) and Bayesian peak fitting techniques shows that the latter can reduce peak intensity uncertainties by a factor of up to ten in the case of closely separated doublets, leading to greatly improved doublet resolution. The need for laboratories to demonstrate the reliability of their chosen peak fitting techniques and measures of peak intensity is also demonstrated. (orig.).

International Nuclear Information System (INIS)

Afterheat represents an important consideration in design of conceptual fusion power reactors, particularly during normal or unplanned shutdown. Afterheat calculations have been undertaken for various generic designs, but with special reference to the Culham DEMO reactor. These calculations have included the redistribution of heating by gamma ray transport. Selected temperature response calculations have been undertaken. (author).

International Nuclear Information System (INIS)

The "8"8Y decay has been studied with the aim to discover emission of monohromatic positrons (MP). The "8"8Sr(d,2N) reaction was used for production of "8"8Y (#beta#"+, Tsub(1/2)=106.6 days) nuclides. The prismatic beta spectrometer has been used to measure spectra of electrons and positrons. No MPs have been found. The resulting upper bound for their emission rate turned out to be lower than theoretically expected one.

Science.gov (United States)

The major purpose of the work described in this report was to use diffusion modeling techniques to calculate the impact on ambient air quality of SO2 emissions from the ASARCO copper smelter in Tacoma, Washington for the existing smelter configuration (51-percent constant emissions control) and for 20 alternative smelter configurations with varying degrees of constant emissions control. The accuracy of the modeling techniques was established by the close correspondence obtained between calculated and observed short-term ground-level SO2 concentrations for 20 selected historical cases, when high hourly SO2 concentrations were measured in the area surrounding the smelter, as well as by the close agreement between calculated and observed annual average concentrations for 1972. The results of the model calculations show that the maximum allowable constant SO2 emission rate consistent ...

British Library Electronic Table of Contents (United Kingdom)

The fossil fuel consumption and pollutant emissions in a coal fired fluidized bed boiler could be reduced by biomass pyrolysis gas reburning. The influence of three kinds of biomass pyrolysis gases on the emission of N2O in a laboratory scale fluidized bed was investigated using the mechanism of GRI3.0 in this paper. The results showed that: the effect of sawdust pyrolysis gas reburning on N2O was more significant than that of rice husk and orange peel under the same conditions; the increase of initial oxygen content from 1% to 8% in flue gas would restrain the decomposition of N2O; the N2O decomposition was enhanced by increasing reaction temperature from 1073.15 K to 1323.15 K, and the decomposition rate may reach 99% at 1223.15 K.

Energy Technology Data Exchange (ETDEWEB)

In the present thesis, the shell structure in exotic nuclei has been investigated. The focus of the work was on finding new experimental data in neutron-rich Cr and proton-rich Ca isotopes. The investigation of light Ca isotopes concentrated on the nucleus {sup 36}Ca which was produced in a knockout reaction from a radioactive {sup 37}Ca beam. For {sup 36}Ca, the excitation energy of the first 2{sup +} state has been measured for the first time. Furthermore, momentum distributions were analyzed using a Monte-Carlo simulation of the knockout reaction. This analysis yielded the contributions of neutrons from individual orbitals to the total knockout cross section. In principle, these may be used to calculate spectroscopic factors, but such a calculation is hampered by difficulties of present knockout-reaction models in predicting precise single-particle cross sections. The measured branching ratio to the ground and excited states, on the other hand, is close to the predicted value. A ...

International Nuclear Information System (INIS)

Experiments have been conducted to study the effect of injection pressure on the combustion process and exhaust emissions of a direct injection diesel engine fueled with Orange Skin Powder Diesel Solution (OSPDS). Earlier investigation by the authors revealed that 30% OSPDS was optimum for better performance and emissions. In the present investigation the injection pressure was varied with 30% OSPDS and the combustion, performance and emissions characteristics were compared with those of diesel fuel. The different injection pressures studied were 215 bar, 235 bar and 255 bar. The results showed that the cylinder pressure with 30% OSPDS at 235 bar fuel injection pressure, was higher than that of diesel fuel as well as at other injection pressures. Similarly, the ignition delay was longer and with shorter combustion duration with 30% OSPDS at 235 bar injection pressure. The brake thermal efficiency was better at 235 bar than ...

Energy Technology Data Exchange (ETDEWEB)

Urea-formaldehyde resin bonded particle board, medium density fiberboard and plywood paneling are used as flooring, wall paneling, for cabinet work and in furniture, and are present in almost every office, home and public building. If large quantities of these products are used in poorly ventilated spaces, high manufacturing quality control is necessary to avoid problems of latent formaldehyde release. Indoor air formaldehyde concentrations depend on the nature of the product, the product surface to air volume (loading) factor, temperature, humidity, age and product emission rates. Standard test methods are now available for measuring product emission rates that make it possible to predict the performance of UF-bonded pressed wood materials if use conditions and environmental parameters are known. Recent modifications in adhesive and board manufacturing parameters have made it possible to reduce ...

Energy Technology Data Exchange (ETDEWEB)

To determine the diagnostic accuracy of iofetamine hydrochloride I 123 (IMP) with single photon emission computed tomography in Alzheimer's disease, we studied 58 patients with AD and 15 age-matched healthy control subjects. We used a qualitative method to assess regional IMP uptake in the entire brain and to rate image data sets as normal or abnormal without knowledge of subjects'clinical classification. The sensitivity and specificity of IMP with single photon emission computed tomography in AD were 88% and 87%, respectively. In 15 patients with mild cognitive deficits (Blessed Dementia Scale score, less than or equal to 10), sensitivity was 80%. With the use of a semiquantitative measure of regional cortical IMP uptake, the parietal lobes were the most functionally impaired in AD and the most strongly associated with the patients' Blessed Dementia Scale scores. These results indicated that IMP ...

Energy Technology Data Exchange (ETDEWEB)

An experimental investigation of premixed methane-air combustion within the one-dimensional porous ceramic burners for various burner configurations is presented. The burner is nonhomogeneous because of different pore size ceramic block used in different section of the burner. Therefore, the thermophysical and transport properties are nonuniform along the burner core length. The burners are constructed of partially stabilized zirconia. The CO and NO{sub x} emissions, flame speed, and flame stability are examined and compared at lean equivalence ratios for five different burner configurations. The sandwich-structured burner has very favorable flame stabilizing characteristic due to the radiation reflecting region. While the combustion proceeds at faster rate than other burner configurations, the radiation reflecting region and the exit surface have low temperature. Thus the NO{sub x} emission can be kept at the same low ...

Energy Technology Data Exchange (ETDEWEB)

The authors summarize EUVE's contribution to the study of the boundary layer emission of high accretion-rate nonmagnetic cataclysmic variables, especially the dwarf novae SS Cyg, U Gem, VW Hyi, and OY Car in outburst. They discuss the optical and EUV light curves of dwarf nova outbursts, the quasi-coherent oscillations of the EUV flux of SS Cyg, the EUV spectra of dwarf novae, and the future of EUV observations of cataclysmic variables.

International Nuclear Information System (INIS)

The decay of "1"0"1Mo to levels in "1"0"1Tc has been studied using the three-parameter (#gamma#-#gamma#-t) coincidence system of HpGe-HpGe detectors. According to the coincidence data, the decay scheme was modified. The positions of 221.80, 318.00, 377.90, 452.50, 515.42, 1011.05 and 1759.72 keV transitions have been arranged again, the transition positions of 104.70, 105.95 and 774.15 keV gamma-rays have been assigned for the first time, the positions of 169.00, 590.91, 980.52 and 1431.68 keV transitions have been reconfirmed, the 1508.01 keV gamma-ray was observed simultaneously for the first time and its transition position has been assigned. The #beta#-intensities and the values of log ft of most levels were calculated. (author)

Energy Technology Data Exchange (ETDEWEB)

Hard X-ray/gamma-ray spectrometers aboard two interplanetary spacecraft, Ulysses and Pioneer Venus Orbiter (PVO), and two near-Earth spacecraft, Yohkoh and Compton Gamma Ray Observatory (GRO/BATSE), are currently in operation. A unique set of circumstances have permitted the observation of the 15 November 1991 (2238 UT) flare by all the four instruments. This intense flare (GOES class X 1.5) was associated with the bright (3B) H-alpha flare located on the disk (S13, W19) in the active region 6919. At the time of the flare, the Ulysses and PVO spacecraft were located respectively 101[degree] and 52[degree] west of the Sun-Earth line. Thus the view angles for the PVO and Ulysses instruments were quite different from those of the near-Earth instruments on GRO and Yohkoh. The preliminary photon energy spectra observed by the four instruments at different times during the flare will be presented and their implications regarding ...

CERN Document Server

Cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) have been regarded as promising semiconductor materials for hard X-ray and Gamma-ray detection. The high atomic number of the materials (Z_{Cd} =48, Z_{Te} =52) gives a high quantum efficiency in comparison with Si. The large band-gap energy (Eg ~ 1.5 eV) allows us to operate the detector at room temperature. However, a considerable amount of charge loss in these detectors produces a reduced energy resolution. This problem arises due to the low mobility and short lifetime of holes. Recently, significant improvements have been achieved to improve the spectral properties based on the advances in the production of crystals and in the design of electrodes. In this overview talk, we summarize (1) advantages and disadvantages of CdTe and CdZnTe semiconductor detectors and (2) technique for improving energy resolution and photopeak efficiencies. Applications of these imaging detectors in future hard X-ray and ...

International Nuclear Information System (INIS)

Oxygen-16 induced fission studies of "2"0"9Bi have been carried out at particle energies of 89.5 MeV using gamma ray spectrometry. The cross sections for the production of fission products have been determined. The yield distribution of fission products has been found to be broad (FWHM #approx =# mass units) with a peak near mass #approx =# 108. The charge distribution in the "1"6O ion induced fission of "2"0"9Bi has also been studied at particle energy of 89.5 MeV. The relative cumulative yields of "9"2Sr, "9"7Zr, "9"9Mo, "1"0"1Mo, "1"1"2Pd and "1"1"7"mCd have been determined using gamma ray spectrometry. The width of charge distribution has been found to be broad. (orig.).

CERN Document Server

The main LHC superconducting magnets (dipoles and quadrupoles) use Rutherford type cables, stabilized electrically and thermally with copper profiles. The portions of cables are connected to each other by a soft soldering technique (Sn96Ag4) with an overlapping length corresponding to one pitch of the superconducting strands. The splice constitutes a "composite" structure with the interchanging layers of Sn96Ag4 and NbTi superconductor, located inside a Cu cage. In order to ensure a high level of reliability (failure probability not exceeding 10-8) for some 10000 connections in the LHC, a non-destructive technique to check the quantity of solder in the joint is foreseen. The technique is based on a gamma ray source (241Am) and the detection is position-sensitive in the transmission mode. Scintillating detectors of gamma rays are used and their accumulated length corresponds to the length of the ...

International Nuclear Information System (INIS)

Molar extinction coefficients of some commonly used solvents (ethanol (C_2H_5OH), methanol (CH_3OH), propanol (C_3H_7OH), butanol (C_4H_9OH), water (H_2O), toluene (C_7H_8), benzene (C_6H_6), carbontetrachloride (CCl_4), acetonitrile (C_4H_3N), chlorobenzene (C_6H_5Cl), diethylether (C_4H_1O) and dioxane (C_4H_8O_2)) have been determined by a well-collimated narrow beam transmission geometry at 279, 356, 662, 1173, 1252 and 1332 keV #gamma# rays. The total #gamma# ray interaction cross sections of these solvents have also been determined. A good agreement has been obtained between the experimental results with the theoretical values evaluated through XCOM calculations.

Energy Technology Data Exchange (ETDEWEB)

The measurements of the K X-ray intensity ratio I(K{alpha} {sub 2}/K{alpha} {sub 1}), I(K{beta} {sub 1}/K{alpha} {sub 1}) and I(K{beta}/K{alpha}) for elements V, Mn, Zn, Tc, Ru, Cd, Xe, Ba, Cs, Hg and Rn were experimentally determined both by photon excitation, in which 59.5 keV {gamma}-rays from a {sup 241}Am and 123.6 keV {gamma}-rays from a {sup 60}Co were used, and following the radioactive decay of {sup 51}Cr, {sup 55}Fe, {sup 67}Ga, {sup 99}Tc, {sup 111}In, {sup 131}I, {sup 133}Ba, {sup 133}Xe, {sup 137}Cs, {sup 201}Tl and {sup 226}Ra. K X-rays emitted by samples were counted by a Si(Li) detector with resolution 160 eV at 5.9 keV. Obtained values were compared with the theoretical values. It was observed that present values agree with the previous theoretical and other experimental results.

International Nuclear Information System (INIS)

Seven types of shellfish were irradiated by gamma ray at doses of 0, 3 and 6 kGy. Pulse photo-stimulated luminescence (PPSL) and thermoluminescence (TL) methods were employed to detect the radiation treatment. The screening of irradiation was carried out by the PPSL method followed by identification using the TL technique. Most of the irradiated shellfish were screened out correctly and only a few showed photon counts a bit higher than the lower threshold value by much lower than the upper threshold value. The TL method was employed using minerals isolated from all the control and irradiated shellfish samples by density gradient treatment. Three parameters, integrated intensities of first glow curves (TL1), ratios of first to that of second glow curves (TL1/TL2), and the shapes of maxima of first glow curves, were utilized for the identification of gamma ray treatment of shellfish. (author)

International Nuclear Information System (INIS)

A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of International Thermonuclear Experimental Reactor (ITER). In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiation resistance of the material, because the material is exposed to severe environments such as high radiation field and low temperature of 4 K. Especially, it is important to estimate the amount of gases evolved from the insulating material by irradiation, because the gases affect on the purifying system of liquid helium in the superconducting coil system. In this work, the gas evolution from the laminated material by gamma ray irradiation at liquid nitrogen temperature (77 K) was investigated, and the difference of gas evolution behavior due to difference of composition in the epoxy resin was discussed. It was found that the main gases ...

International Nuclear Information System (INIS)

The 9.50 GHz electron paramagnetic resonance (EPR) spectra of unirradiated and "6"0Co #gamma#-ray irradiated cardamom (Elettaria cardamomum L. Maton, Zingiberaceae), ginger ((Zingiber officinale Rosc., Zingiberaceae), and saffron (Crocus sativus L., Iridaceae) have been investigated at room temperature. All unirradiated spices presented a weak resonance line with g-factors around free-electron ones. After #gamma#-ray irradiation at an absorbed dose of up to 11.3 kGy, the presence of EPR spectra whose amplitude increase monotonously with the absorbed dose has been noticed with all spices. A 100 "oC isothermal annealing of 11.3 kGy irradiated samples has shown a differential reduction of amplitude of various components that compose initial spectra, but even after 3.6 h of thermal treatment, the remaining amplitude represents no less then 30% of the initial ones. The same peculiarities have been noticed after 83 days storage at room temperature ...

Energy Technology Data Exchange (ETDEWEB)

The molar of guinea pigs was irradiated with /sup 60/Co-..gamma.. ray for daily observations of the manifestation of disturbed tooth formation by microradiography and the time registration by tetracycline-labelling. Irradiation first injured young blast cells of the dentin in the growth phase, dental pulp cells, and cells of the enamel. The portion composed of injured cells formed a depressed ''constriction'' from the dental pulp side toward the border between the enamel and dentin. The cells of the enamel injured by irradiation in the growth phase later formed a very thin irregular stroma. In contrast, cells in the differentiation or subsequent phase at the time of irradiation and cells probably having started to grow after irradiation proceeded with formation of a normal stroma and calcification. No uniform relation was obtained between the histological staining of the organic stroma of normal or abnormal ...

International Nuclear Information System (INIS)

A method that employs simultaneous neutron and #gamma#-ray diffraction techniques is proposed for accurate measurements of strains with or without an applied electric field (0-100 kV m"-"1). Instead of an absolute determination of the position of the neutron Bragg peak, a relative measurement of the neutron and #gamma# peak positions is used and allows a determination of the lattice-parameter changes with an accuracy of within 2 x 10"-"6. This technique avoids systematic errors originating in sample rotations by taking advantage of a reference directly related to the crystal lattice. The method appears to be particularly important for crystals that exhibit structural phase transitions, as demonstrated by the measurement of the strain U_x_x in KH_2PO_4 crystals as a function of temperature and applied electric field. In this case the errors would amount to #+-#20%. The results demonstrate the need to re-examine the theory previously proposed by Uesu, Tanaka and ...

Energy Technology Data Exchange (ETDEWEB)

The flux of cosmic ray antiprotons with kinetic energies between /approximately/1 and 15 GeV is /approximately/5 times greater than the flux predicted on the basis of the leaky-box model. This excess is attributed to secondary antineutron production in compact sources. Because the antineutrons are not confined by the magnetic field of the compact source, they leave the interaction site, decay in interstellar space and account for the apparent excess cosmic ray antiproton flux. The escape and decay of neutrons produced in association with the antineutrons is a source of cosmic ray protons. Observations of the angular variation of the intensity and spectral shape of 100 MeV ..gamma..-rays produced by neutron-decay protons in the reaction p + p ..-->.. ..pi../sup 0/ ..-->.. 2..gamma.. could reveal compact-source cosmic ray production sites. COS-B observations of spectral hardening near point sources, and future high-resolution observations of galactic point ...

CERN Document Server

Recent data from CREAM seem to confirm early suggestions that primary cosmic ray spectra at few TeV/nucleon are harder than in the 10-100 GeV range. Also, helium and heavier nuclei spectra appear systematically harder than the proton fluxes at corresponding energies. We note here that if the measurements reflect intrinsic features in the interstellar fluxes, appreciable modifications are expected in the sub-TeV range for the secondary yields, such as antiprotons and diffuse gamma-rays. Presently, this effect represents a systematic error in the extraction of astrophysical parameters as well as for background estimates for indirect dark matter searches. We find that the spectral modifications are appreciable above 100 GeV, and can be responsible for ~30% effects for antiprotons at energies close to 1 TeV or for gamma's at energies close to 300 GeV, compared to currently considered predictions based on simple extrapolation of input fluxes from low energy data.

International Nuclear Information System (INIS)

Using acrylic-group containing isocyanates together with methyl methacrylate as impregnating mixture and gamma rays for curing wood-plastic composites have been produced, which show high-dimensional stability and toughness (low brittleness) compared to commonly used wood-plastics. The syntheses of proper acrylic-group containing isocyanates are as well described as the properties of the produced composites, made from maple wood. Also the direct use of the initial compounds, necessary for the syntheses, resulted in products of similar properties. These wood-plastic composites are to be suggested for the production of high-class products, e.g. wood-wind instruments. (author).