International Nuclear Information System (INIS)

An investigation of the Ll x-#gamma# angular correlations following the decay of "2"0"7Bi is done by using a Si(Li) semiconductor counter as L x-ray detector. Coincidence measurements at five different angles were made between the 570-keV #gamma# ray (gated in the movable counter) and the Ll x spectrum (displayed in a multichannel analyzer).

International Nuclear Information System (INIS)

Time-differential magnetic moment measurements on the first-excited Isup(#pi#)=2"+ states in "2"0Ne and "2"4Mg with mean lives of 1.0 and 2.1 ps, respectively are described. The lifetime of the latter state was determined simultaneously. A special detection geometry was designed to improve the experimental #gamma#-ray anisotropy measured with finite-size detectors. For "2"0Ne also a time-integral measurement with charge-state separation was performed. The necessary electronics circuitry built to perform these complicated measurements and the plunger assembly with laser interferometer are also described. A magnetic moment measurement of "2"2Ne(2_1"+) with tau=5.0 ps and transient field measurements at low and high recoil velocities are reported. A discussion of possible extensions of the techniques are given. (Auth.).

International Nuclear Information System (INIS)

The wavefunction of a positron in ReO is calculated using the augmented-plane-wave method. Due to the loosely-packed structure of ReO_3, the ground-state GAMMA_1 wavefunction exhibits a marked anisotropy particularly around the oxygen ions, and a large fraction of a positron is distributed in the interstitial region. Experimental results of the positron annihilation 2#gamma#-correlations and the positron annihilation rates in ReO_3 are discussed based on the positron wavefunction. (orig.).

Energy Technology Data Exchange (ETDEWEB)

We report the experimental and theoretical results on the anisotropies in the magnetic properties and x-ray absorption spectra of single-crystal LiFePO4. A mean-field theory is developed to explain the observed strong anisotropies in Lande g-factor, paramagnetic Curie temperature, and effective moment for LiFePO4 single crystals. The values of the in-plane nearest- and next-nearest-neighbor spin exchange (J1 and J2), interplane spin exchange (J{perpendicular}), and single-ion anisotropy (D), obtained recently from neutron scattering measurements, are used for calculating the Curie temperatures with the formulas derived from the mean-field Hamiltonian. It is found that the calculated Curie temperatures match well with that obtained by fitting the magnetic susceptibility curves to the modified Curie-Weiss law. For the polarized Fe K-edge x-ray absorption spectra of single-crystal LiFePO4, a different ...

International Nuclear Information System (INIS)

In the paramagnetic region T > 178 K the paramagnetic susceptibility, chi, of Dy was measured as a function of temperature and orientation of the applied magnetic field with respect to the c-axis. For magnetic fields parallel and perpendicular to the c-axis the temperature dependence of chi can be represented by Curie-Weiss laws whereas for arbitrary orientations significant deviations from a Curie-Weiss behaviour were found. The measured anisotropy of the paramagnetic Curie temperatures and of the Curie-Weiss constants is shown to depend mainly on the magnetocrystalline energy and an anisotropic g-factor. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

We present methods to measure the beam polarizations and the luminosity of [gamma][gamma] colliders at TeV energy scale. The beam polarizations of a [gamma][gamma] collider can easily be monitored by comparing the numbers of events of the processes [gamma][gamma] [yields] l[sup +]l[sup -] and [gamma][gamma] [yields] W[sup +] W[sup -], where l means e or [mu]. The luminosity of a [gamma][gamma] collider is also measurable by the event rate of W boson pair productions and the light lepton pair productions. (orig.)

International Nuclear Information System (INIS)

The angular #gamma##gamma#-correlations for nuclei of Sr even-even isotopes with a=8 82, 84, 86, 88 were measured. Multipole structurs of #gamma#-transtion series and th coefficients multipole mixing were determined.

International Nuclear Information System (INIS)

We summarize the predictions of different models for total #gamma##gamma# cross-sections. The experimentally observed rise of #sigma#_#gamma#_#gamma# with s radical _#gamma#_#gamma#, faster than that for #sigma#_p_-_b_a_r_p, #sigma#_#gamma#_p is in agreement with the predictions of the Eikonalized Minijet Models as opposed to those of the Regge-Pomeron models. We then show that a measurement of #sigma#_#gamma#_#gamma# with an accuracy of < or approx. 8-9% (6-7%) is necessary to distinguish among different Regge-Pomeron type models (the different parameterisations of the EMM models) and a precision of < or approx. 20% is required to distinguish the predictions of the EMMs and of those models which treat 'photon like a proton', for the energy range 300< s radical_#gamma#_#gamma# <500 GeV. We further show that the difference in ...

International Nuclear Information System (INIS)

The paramagnetic susceptibility of single crystals of dysprosium-yttirum alloys is measured in the basal plane and along the hexagonal axis. It is shown that the susceptibility of the alloys obeys the Curie-Weiss law, the effective magnetic moments allong the different directions being the same and the paramagnetic Curie temperatures being different. The difference between the paramagnetic Curie temperatures in the basal plane and along the hexagonal axis is independent of the dysprosium concentration in the alloy. As a comparison with the theoretical models of magnetic anisotropy shows, this is an indication that the magnetic anisotropy of dysprosium - yttrium alloys is of a single-ion nature.

Science.gov (United States)

Nonparabolicity of the heavy hole band in diamond-like semiconductors, which occurs within the framework of the three band model with the perturbation from the other bands taken into account according to the Loewdin procedure, is studied. A direct dependence of nonparabolicity on the band anisotropy (caused by the different effect of Gamma/sub 15c/ and Gamma/sub 12c/ bands) and the inverse dependence on the magnitude of the spin-orbit splittiing is established. A connection between the effective mass of heavy holes and their energy is obtained, which is valid for the majority of diamond-like semiconductors, except for materials with a very strong nonparabolicity of the band of silicon type

International Nuclear Information System (INIS)

The cross sections of neutral tensor mesons T=a_2, f, f', ... production in the exclusive #gamma##gamma##->#TT' or semiexclusive #gamma##gamma##->#TX processes (three gluon exchange) in the semihard region s>>vertical stroketvertical stroke>1 GeV"2 are calculated. The relation of investigated processes to the problem of perturbative Odderon is discussed. The possibility of measurements at LEP and at a future #gamma##gamma#-colliders is discussed too. (orig.).

International Nuclear Information System (INIS)

A #gamma##gamma# collider would extend and complement the physics capability of a linear collider; e.g. it would be suitable for direct measurement of the partial decay width of a Higgs boson into two gamma quanta. This paper discusses choice of laser parameters, luminosity optimization, electron and laser parameters for a gamma- gamma collider as a second interaction region for the Next Linear Collider, laser path, and the lasers. It is concluded that a gamma- gamma collider is technically feasible; however it will require a significant investment in preparatory R ampersand D.

Energy Technology Data Exchange (ETDEWEB)

In the framework of the equivalence theorem the one-loop helicity amplitudes and cross section for the double Higgs production process {gamma}{gamma}{yields}HH are calculated. It is shown that the cross section is measurable at TeV {gamma}{gamma} colliders and is marginally sensitive to the triple-Higgs variation. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The cross sections of neutral tensor mesons T=a{sub 2}, f, f', ... production in the exclusive {gamma}{gamma}{yields}TT' or semiexclusive {gamma}{gamma}{yields}TX processes (three gluon exchange) in the semihard region s>>vertical stroketvertical stroke>1 GeV{sup 2} are calculated. The relation of investigated processes to the problem of perturbative Odderon is discussed. The possibility of measurements at LEP and at a future {gamma}{gamma}-colliders is discussed too. (orig.).

International Nuclear Information System (INIS)

Measurements are made on the principal magnetic susceptibilities and anisotropies of praseodymium selenate octahydrate single crystals in the temperature range 90 to 300 K. Although the effective magnetic moment is close to the free ion value, the anisotropy is quite high at room temperature. A least sequares fit of the Curie-Weiss law to the observed average susceptibility yields -36.5 K as the paramagnetic Curie temperature. An analysis of the results with a crystal field (CF) of D_4 symmetry, explains the observed results quite well. The CF and the spin-orbit interaction matrix is block diagonalized in the complete 33 dimensional basis of the "3H term in order to obtain the Stark energies and their eigenstates. Intermediate coupling effects are also considered. The ground state being a singlet, the g-factors are absent. Some predictions on the electronic heat capacity and the electronic quadrupole splitting are made in ...

Energy Technology Data Exchange (ETDEWEB)

A procedure and software have been developed to transform the area distribution of the residual surface heights available from the measurement with the Micromap interferometric microscope into a two-dimensional (2D) power spectral density (PSD) distribution of the surface height. The procedure incorporates correction of one of the spectral distortions of the PSD measurement. The distortion appears as a shape difference between the tangential and sagittal PSD spectra deduced from the 2D PSD distribution for an isotropic surface. A detailed investigation of the origin of the anisotropy was performed, and a mathematical model was developed and used to correct the distortion. The correction employs a modulation transfer function (MTF) of the detector deduced analytically based on an experimentally confirmed assumption about the origin of the anisotropy due to the asymmetry of the read-out process of the ...

International Nuclear Information System (INIS)

We investigate the sparticle production processes e#gamma# #-># e tilde(Z tilde)_1 and #gamma##gamma# #-># (f tilde)(f tilde and bar) at high energy e#gamma# and #gamma##gamma# colliders in the framework of the minimal supersymmetric standard model (MSSM). It will be shown that the e#gamma# colliders would be more suitable in searching for the heavy selectrons than ee colliders because of the low mass threshold of the process e#gamma# #-># (e tilde)(Z tilde)_1. We show that the standard background processes e#gamma# #-># #nu#W and eZ can be suppressed in terms of initial beam polarization as well as the kinematical cuts on the energy and angle of the final electron. Moreover, it will be argued that the experimental measurements of the cross sections for the processes e#gamma# #-># (e ...

CERN Document Server

The decay modes $\\jpsi\\ar\\gamma\\pi^0, \\gamma\\eta$ and $\\gamma\\etap$ are analyzed using a data sample of 58 million $\\jpsi$ decays collected with the BESII detector at BEPC. The branching fractions are determined to be: $Br(\\jpsi\\ar\\gamma\\pi^0)=(3.13^{+0.65}_{-0.44})\\times10^{-5}$, $Br(\\jpsi\\ar\\gamma\\eta)=(11.23\\pm0.89)\\times10^{-4}$, and $Br(\\jpsi\\ar\\gamma\\etap)=(5.55\\pm0.44)\\times10^{-3}$, where the errors are combined statistical and systematic errors. The ratio of partial widths $\\Gamma(\\jpsi\\ar\\gamma\\etap)/\\Gamma(\\jpsi\\ar\\gamma\\eta)$ is measured to be $4.94\\pm0.40$, and the singlet-octet pseudoscalar mixing angle of $\\eta-\\etap$ system is determined to be $\\theta_{P}=(-22.08\\pm0.81)^{\\circ}$.

International Nuclear Information System (INIS)

In 1998, research began at Idaho National Engineering and Environmental Laboratory to investigate the application of "6Li and "7Li isotopes to the measurement of neutron and gamma radiation. Various size pairs of "6Li and "7Li based detectors were exposed to mixed neutron and gamma radiation. Experiments demonstrated that these detectors could be used to measure low level neutron radiation in the presence of high level gamma radiation. (author)

International Nuclear Information System (INIS)

"1"0"1Mo is one of the key nuclides in diagnosing fission burn-up. However, it's difficult to measure its nuclear decay data due to its short half-life. Present study concerns in the measurements of #gamma#-ray emission probabilities, P_#gamma#, of "1"0"1Mo and "1"0"1Tc using the balance of scheme method and the entire process recording. The P_#gamma# of "1"0"1Mo by the entire process recording is about 5% lower than that by using the balance of scheme method. The P_#gamma# of "1"0"1Tc using the two methods agree each other very well. So, it seems the #gamma#-ray emission probabilities as well as measurement method still need study further for "1"0"1Mo. (authors)

Energy Technology Data Exchange (ETDEWEB)

We investigate the semihard production of neutral pseudoscalar and tensor mesons in high-energy [gamma][gamma] collisions (M=P=[pi][sup 0], [eta], [eta]' or M=T=a[sub 2], f[sub 2], f[sub 2]'). We deal with the exclusive [gamma][gamma][yields]MM' or semi-exclusive [gamma][gamma][yields]MX reactions (X is the hadron jet with not too large mass). The considered transfer momenta are small in comparison with the photon energies and they are large in comparison with the confinement scale. The amplitudes of these processes are determined by the odderon exchange, i.e. three-gluon exchange in the lowest order of perturbative QCD. The cross sections are calculated in this approximation. The possibility of measurements at LEP and at future [gamma][gamma] colliders is discussed. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The working group reviewed the main difficulties foreseen in doing physics at a gamma-gamma collider. They discussed the requirements for the detector, calculated some of the signal and background rates, compared methods of measuring luminosity, looked at how to get the laser beams in, investigated ways of sweeping aside the electrons and considered ways of disposing of the used beams. No overwhelming obstacles were found but important questions still need to be answered. ((orig.)).

CERN Document Server

Using $\\gamma \\gamma J/\\psi, J/\\psi \\ra e^+ e^-$ and $\\mu^+ \\mu^-$ events from a sample of $14.0\\times 10^6$ $\\psip$ decays collected with the BESII detector, the branching fractions for $\\psip\\ra \\pi^0\\J$, $\\eta\\J$, and $\\psi(2S)\\ar\\gamma\\chi_{c1},\\gamma\\chi_{c2}\\ar\\gamma\\gamma\\jpsi$ are measured to be $B(\\psip\\ra \\pi^0\\J) = (1.43\\pm0.14\\pm0.13)\\times 10^{-3}$, $B(\\psip\\ra \\eta\\J) = (2.98\\pm0.09\\pm0.23)%$, $B(\\psi(2S)\\ar\\gamma\\chi_{c1}\\ar\\gamma\\gamma\\jpsi) = (2.81\\pm0.05\\pm 0.23)%$, and $B(\\psi(2S)\\ar\\gamma\\chi_{c2}\\ar\\gamma\\gamma\\jpsi) = (1.62\\pm0.04\\pm 0.12)%$.

Energy Technology Data Exchange (ETDEWEB)

The {rvec n} + p {yields} d + {gamma} experiment under construction at LANSCE studies the weak interaction between neutrons and protons. The experiments will measure the directional dependence of the parity-violating {gamma}-ray asymmetry, A{sub {gamma}}, in the polarized cold neutron capture by para-hydrogen. The goal is to measure A{sub {gamma}} with uncertainty of 0.5 x 10{sup -8}, 10% of its predicted value. A{sub {gamma}} primarily isolates the {Delta}I = 1 component of the hadronic weak interaction and thus will determine the long-range weak pion-nucleon coupling constant H{sub {pi}}{sup 1}. The experiment is carefully designed for the LANSCE pulsed spallation neutron source to achieve the proposed statistical precision and to control systematic errors. We discuss the experiment and its status.

International Nuclear Information System (INIS)

Reflectance anisotropy spectroscopy (RAS) has been used, together with scanning tunnelling spectroscopy (STS), to investigate the optical and electronic properties of nanodots formed by depositing Ag on the Si(111)-3 x 1-Ag surface. One-dimensional (1D) arrays of nanodots were grown on a single-domain (3 x 1)-Ag surface and the anisotropic optical response in the 0.5-5 eV range measured by RAS. Aligned, elongated Ag islands were also grown on this surface to compare their properties with those of the nanodots. STS of the Ag islands showed distinct metallic behaviour, whereas the nanodots revealed a bandgap of #approx#0.6 eV, indicating that the surface of the dots has a non-metallic character, similar to that of the Si(111)-3 x 1-Ag surface. RAS also showed substantial differences between the structures, with a large infrared anisotropy for the metallic Ag islands consistent with anisotropic Drude-like intraband ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

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.

International Nuclear Information System (INIS)

We present the effects of heavy CP-even (H) and CP-odd (A) Higgs bosons on the production cross section of the process #gamma##gamma##->#tt at the energy around the mass poles of the Higgs bosons. It is found that interference between H and A with small mass gap, as well as the ones between Higgs bosons and continuum, contributes to the cross section, if the photon beams are polarized and if we observe the helicity of the top quarks. It is demonstrated in the framework of the minimal supersymmetric extension of the standard model that the H and A contributions can be sizable at future #gamma##gamma# colliders for small values of tan #beta#. The methods to measure the CP-parity of the Higgs boson are also presented. The statistical significance of detecting the Higgs signals and measuring the Higgs CP-parity is evaluated. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The NPDGamma Experiment measures the parity-violating correlation A{sub {Gamma}Y} between neutron spin and photon momentum in the reaction {rvec n} + p {yields} d + {gamma}. Knowledge of A{sub {Gamma}Y} and other parity-violating observables in few-body nuclear systems will provide constraints for a parameterized description of {Delta}S = 0 parity-violating phenomena free from complications of nuclear structure. The NPDGamma experiment uses a polarized cold pulsed neutron beam, a liquid parahydrogen target, and a cylindrical array of 48 CsI(Tl) scintillation detectors operated in current mode to search for the asymmetry. NPDGamma recently completed the first phase of the program to measure A{sub {Gamma}Y} at the Los Alamos Neutron Science Center with the preliminary result A{sub {Gamma}Y} = (-1.2 {+-} 2.1(stat.) {+-} 0.1(sys.)) x 10{sup -7}, ...

Energy Technology Data Exchange (ETDEWEB)

The work in the past year has primarily involved four areas of magnetic thin films: amorphous rare earth-transition metal alloys, epitaxial CoPt{sub 3} and Ni-Pt alloy thin films, amorphous rare earth doped Si (a new class of dilute magnetic semiconductor with large negative magnetoresistance which the authors have discovered), and exchange-coupled antiferromagnetic insulators. In the amorphous alloys, they made a systematic study of the effects of local anisotropy, macroscopic (perpendicular) anisotropy, and exchange constant on the fundamental (and practical) properties of these magnetic alloys, as originally described in the grant proposal. The work on the epitaxial Co-Pt (and more recently Ni-Pt) alloys was originally undertaken as a comparison study to the amorphous alloys. Crystalline Co-Pt alloys have many striking similarities to the amorphous rare earth-transition metal alloys: perpendicular magnetic anisotropy, ...

Energy Technology Data Exchange (ETDEWEB)

The dd{yields}{sup 4}He{eta} reaction has been investigated near threshold using the ANKE facility at COSY-Juelich. Both total and differential cross-sections have been measured at two excess energies, Q=2.6 MeV and 7.7 MeV, with a subthreshold measurement being undertaken at Q=-2.6 MeV to study the physical background. While consistent with isotropy at the lower energy, the angular distribution reveals a pronounced anisotropy at the higher one, indicating the presence of higher partial waves. Options for the decomposition into partial amplitudes and their consequences for the determination of the s-wave {eta}{alpha} scattering length are discussed. (orig.)

International Nuclear Information System (INIS)

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)

Certain problems of gamma-absorption method of measuring the thickness of layers in multi-layer items are analyzed. Two examples of solving the above-mentioned problems have been considered. One of them deals with a two-layer item, its integral thickness being known or measured in advance, the second example is referred to a two-layer item with unknown integral value

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.

International Nuclear Information System (INIS)

This article introduces the composition, monitoring methods and working principles of environmental #gamma# dose rate continuous monitoring system at Guangdong Daya Bay Nuclear Power Station. The #gamma# dose rate monitoring status after modification of measurement conditions is introduced too.

Energy Technology Data Exchange (ETDEWEB)

The detection efficiency of gamma scanning system in irradiated materials examination facility has been measured. Gamma-ray sources used in this experiment are Cs-Co standard sources a PWR spent fuel rod in which {sup 134}Cs and {sup 154}Eu peaks are clearly identified in the energy region of 500 to 1,600 keV. The distance between source and detector is about 1.6 m. A slit type collimator with 3 mm-width window and 30 mm-thick lead block are installed between source and detector. The detector is a HPGe detector. This equipment is mainly used in gamma scanning of irradiated nuclear fuel. The measured detection efficiency seems to be 1.89 x 10{sup -6} % for 1 MeV gamma-ray. With these results the activities of unknown sources could be measured. This results are expected to be used in the measurement of the absolute ...

Energy Technology Data Exchange (ETDEWEB)

We review some interesting virtual effects from the minimal supersymmetric model (MSSM) at {gamma}{gamma} colliders. We conclude that in the research respects, such as supersymmetric particle pair production, CP-violation and electroweak-like one-loop corrections in top quark pair production, the FCNC in the R{sub p}-violating MSSM, linear collider (LC) operating in photon-photon collision mode provides powerful facilities in the measurements of new physics objects. For a precise and thorough study of the new physics, the investigation of the supersymmetric quantum effects is necessary. (author)

Energy Technology Data Exchange (ETDEWEB)

Short communication.

International Nuclear Information System (INIS)

Short communication.

CERN Document Server

The full theory and the semiclassical description of loop quantum cosmology (LQC) have been studied in the Friedmann-Robertson-Walker and Bianchi I models. As an extension to include both anisotropy and intrinsic curvature, this paper investigates the cosmological model of Kantowski-Sachs spacetime with a free massless scalar field at the level of phenomenological dynamics with the LQC discreteness corrections. The LQC corrections are implemented in two different improved quantization schemes. In both schemes, the big bang and big crunch singularities of the classical solution are resolved and replaced by the big bounces when the area or volume scale factor approaches the critical values in the Planck regime measured by the reference of the scalar field momentum. Symmetries of scaling are also noted and suggest that the fundamental spatial scale (area gap) may give rise to a temporal scale. The bouncing scenarios are in an analogous fashion of ...

International Nuclear Information System (INIS)

Stellar rotation velocities and velocity dispersions along three slit positions in M31 have been measured, and three-dimensional velocity and velocity dispersion fields are obtained in order to search for a central black hole. Synthetic apparent spectra are constructed to eliminate problems with the reaction of the Fourier quotient program to stellar population mixes. Models are constructed to explore parameter space. The large velocities and velocity gradients that are found imply that the total mass-to-light ratio rises sharply at r of 0.5 arcsec or less to values greater than 100. This is much larger than normal for old stellar populations. Velocity anisotropies are not a major uncertainty because of the rapid rotation. There is thus strong evidence for a dark central mass, probably a supermassive black hole. 48 references.

CERN Document Server

The next decade promises an observational revolution which will change cosmology forever. The precise measurement of the angular anisotropy of the cosmic microwave background should specify to a few percent all of the parameters of the cosmological model which effect astrophysics. The growth of structure will then be determined (but not yet observed) until gravitational collapse becomes highly non-linear and stars, galaxies and active galactic nuclei (AGN) form. These processes are hard to model with basic physics because they are complex and allow a rich variety of expression. Instead observations will determine when the first stars and quasars formed, and how and when galaxies assembled. If we can reconcile the numerous contradictions which characterize the subject today, cosmology will become a mature subject, founded on the agreement between detailed, inclusive and realistic models, which make precise predictions, and the wealth of new data ...

International Nuclear Information System (INIS)

In this report, I surveyed physics potential of the #gamma##gamma# option of a linear e"+e"- collider with the following questions in mind: What new discovery can be expected at a #gamma##gamma# collider in addition to what will be learned at its 'parent' e"+e"- linear collider? By taking account of the hard energy spectrum and polarization of colliding photons, produced by Compton back-scattering of laser light off incoming e"- beams, we find that a #gamma##gamma# collider is most powerful when new physics appears in the neutral spin-zero channel at an invariant mass below about 80% of the c.m. energy of the colliding e"-e"- system. If a light Higgs boson exists, its properties can be studied in detail, and if its heavier partners or a heavy Higgs boson exists in the above mass range, they may be discovered at a #gamma##gamma# collider. CP property of the scalar sector can be explored in detail by ...

International Nuclear Information System (INIS)

A Monte Carlo simulation of the vacuum Bianchi type-IX (mixmaster) cosmology yields a significant correlation between large universe volume and high anisotropy. An analog of the model's chaotic classical behavior is seen in the break up of the universe wave function at large volume into fingers in the corners of the minisuperspace anisotropy potential.

UK PubMed Central (United Kingdom)

BackgroundFourier Transform Infrared Imaging (FTIRI) is used to investigate the amide anisotropies at different surfaces of a three-dimensional cartilage or tendon block. With the...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

An indoor survey in order to estimate the population exposure in five towns of an Italian Region is presented. A particular methodology for the campaign was planned and is being applied. Gamma spectrometry of building materials, exposure rate measurements indoors and outdoors and radon concentration measurements indoors were taken with different techniques. A correlation was found between mean gamma exposure rate and mean radon concentration in the houses investigated. An evaluation of mean effective dose equivalents for the inhabitants of the five towns is reported.

CERN Document Server

By fitting the R values between 3.7 and 5.0 GeV measured by the BES collaboration, the upper limit of the electron width of the newly discovered resonance Y(4260) is determined to be 240 eV at 90% C.L., together with the BABAR measurement on the product of Gamma_{ee} and BR(Y(4260) --> pi+pi- J/psi), this implies a large decay width of Y(4260) --> pi+pi- J/psi final states.

Energy Technology Data Exchange (ETDEWEB)

In the investigations reported here, a helium-jet/tape-transport system was used for the rapid transfer of fission products to a low-background environment where their aggregate beta and gamma-ray spectra were measured as a function of delay time after neutron induced fission of {sup 235}U, {sup 238}U and {sup 239}Pu. Beta and gamma-ray energy distributions have been deduced for delay times as short as 0.2 s and extending out to 100,000s. Instrumentation development during the initial phase of the project included: (1) assembly and characterization of a NaI(Tl) spectrometer for determining aggregate gamma-ray energy distributions, (2) development and characterization of a beta spectrometer (having excellent gamma-ray rejection) for measuring aggregate beta-particle energy distributions, (3) assembly and characterization of a Compton-suppressed HPGe spectrometer ...

Energy Technology Data Exchange (ETDEWEB)

In 1959, the Test Manager's Committee to Establish Fallout Doses calculated estimated external gamma exposure at populated locations based upon measurements of external gamma-exposure rate. Using these calculations and estimates of population, we have tabulated the collective estimated external gamma exposures for communities within established fallout patterns. The total collective estimated external gamma exposure is 85,000 person-R. The greatest collective exposures occurred in three general areas: Saint George, Utah; Ely, Nevada; and Las Vegas, Nevada. Three events, HARRY (May 19, 1953), BEE (March 22, 1955), and SMOKY (August 31, 1957), accounted for over half of the total collective estimated external gamma exposure. The bases of the calculational models for external gamma exposure of ''infinite ...

International Nuclear Information System (INIS)

The wave function of the Bianchi type-IX universe with small anisotropy is calculated using the Hartle-Hawking prescription.

International Nuclear Information System (INIS)

The spherical harmonic analysis of cosmic ray neutron data from the worldwide network neutron monitor stations during the years 1966 to 1969 was carried out. The second zonal harmonic component obtained from the analysis corresponds to the Pole-Equator anisotropy of the cosmic ray neutron intensity. Such an anisotropy makes a semiannual variation. In addition to this, it is shown that the Pole-Equator anisotropy makes a variation depending on the interplanetary magnetic field (IMF) sector polarities around the passages of the IMF sector boundary. A mechanism to interpret these results is also discussed.

Energy Technology Data Exchange (ETDEWEB)

In the future, the demand for energy is predicted to grow and more countries plan to utilize nuclear energy as their source of electric energy. This gives rise to many important issues connected to nuclear energy, such as finding methods that can verify that the spent nuclear fuel has been handled safely and used in ordinary power producing cycles as stated by the operators. Gamma ray spectroscopy is one method used for identification and verification of spent nuclear fuel. In the specific gamma ray spectroscopy method called gamma scanning the gamma radiation from the fission products Cs-137, Cs-134 and Eu-154 are measured in a spent fuel assembly. From the results, conclusions can be drawn about the fuels characteristics. This degree project examines the possibilities of using alternative measuring approaches when using the gamma scanning ...

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)

The #gamma# rays following the #beta# decays of "8"8Kr and "8"8Rb have been studied, using both large volume Ge(Li) detectors for singles and coincidence measurements and anti-Compton spectrometry for singles measurements. Level schemes for "8"8Rb and "8"8Sr were constructed from the data and 74 of 81 #gamma# rays observed in the decay of "8"8Kr were placed in the "8"8Rb level scheme with 23 excited states. For the decay of "8"8Rb, all of the observed 27 #gamma# rays have been placed in the (well known) level structure of "8"8Sr. Spin and parity assignments have been deduced from #beta#-decay logft values and #gamma#-ray transition patterns. Possible shell model interpretations are presented for the level schemes.

Energy Technology Data Exchange (ETDEWEB)

The proton beam has an advantage of the sharp dose falloff in dose distribution called Bragg peak while conventional radiation therapy modalities such as photons exhibit considerable amount of exit dose. To take advantage of this property it is important to know the exact location of the distal dose falloff. An error can cause overdose to the normal tissue or underdose to the tumor volume. The only way of finding out the dose distribution in-situ in particle therapy is to measure the gammas produced by nuclear reactions with tissue materials. Two kinds of gammas can be used: one is prompt gamma and the other is coincident gamma from the positron-emission isotopes. We chose to detect prompt gammas, and developed a prompt gamma scanning system (PGS). The proton beams of the proton therapy facility at National Cancer Center were used. The ...

International Nuclear Information System (INIS)

Stellar rotation and velocity-dispersion measurements are presented for the bulge components of the SBO galaxies NGC 1023, 2859, 2950, 4340, 4371, and 7743. The kinematics of nine SB bulges with data available are compared with bulges of unbarred galaxies studied by Kormendy and Illingworth. All of the SB bulges are found to rotate at least as rapidly as oblate-spheroid dynamical models which are flattened by rotation. This result confirms the conclusion of Kormendy and Illingworth that bulges rotate very rapidly. Six SB bulges found by Kormendy and Koo to be triaxial rotate even more rapidly than the oblate models. In this respect, they resemble published n-body models of bars. That is, triaxial bulges are dynamically like bars and unlike elliptical galaxies, which are also believed to be triaxial, but which rotate slowly. Measured velocity anisotropies are found to be consistent with these conclusions. Two ordinary bulges ...

Energy Technology Data Exchange (ETDEWEB)

A algorithm was developed to determine the characteristic parameters of PWR spent fuel, such as burnup, cooling time and initial enrichment of {sup 235}U by use of gamma-ray activity ratios of {sup 134}Cs/{sup 137}Cs, {sup 154}Eu/{sup 137}Cs and {sup 106}Ru/{sup 137}Cs from the high resolution gamma-ray spectroscopy and ORIGEN-S calculations. For the verification of the method developed, gamma-ray measurements of Kori-1 and Kori-2 nuclear fuel rods were carried out using HPGe gamma ray scanning system. As a results, it is revealed that the measured values are in a good agreement with the operator declared values within the about {+-} 5% errors. Besides, the under-water burnup measuring device has been designed to measure the gamma-ray from the PWR spent fuel assembly. This device will be set up in ...

Energy Technology Data Exchange (ETDEWEB)

We examine the virtual effects of Kaluza-Klein (KK) states on Higgs physics in universal extra dimension models. We study the partial widths {Lambda}{sub h{yields}gg}, {Lambda}{sub h{yields}{gamma}{gamma}}, and {Lambda}{sub h{yields}{gamma}Z}, which are relevant for Higgs production and detection in future collider experiments. These interactions occur at one loop in the Standard Model, as do the KK contributions. We find that the deviations induced by the KK exchanges can be significant; for one extra dimension, the gg {yields} h production rate is increased by 10% - 85% for the mass of the first KK state in the range 500 {approx}> m{sub 1} {approx}> 1500 GeV, a region untested by current direct search and precision measurement constraints. The h {yields} {gamma}{gamma} decay width is decreased by {approx}< 20% in the same mass range. For two or more universal extra dimensions the ...

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 the GALPROP model everywhere except for the Cygnus region (l ...

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.

International Nuclear Information System (INIS)

Power density measurements in the critical facility RA-8 are presented. These measurements were the first systematic use of the reactor. A measurement system was designed, built and proved for this goal. Power profiles are showed and the results are compared with calculated values. (author)

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.)

International Nuclear Information System (INIS)

In Sweden, spent nuclear fuel will be encapsulated and placed in a deep geological repository. In this procedure, reliable and accurate spent fuel data such as discharge burnup, cooling time and residual heat must be available. The gamma scanning method was proposed in earlier work as a fast and reliable method for the experimental determination of such spent fuel data. This thesis is focused on the recent achievements in the development of a pilot gamma scanning system and its application in measuring spent fuel residual heat. The achievements include the development of dedicated spectroscopic data-acquisition and analysis software and the use of a specially designed calorimeter for calibrating the gamma scanning system. The pilot system is described, including an evaluation of the performance of the spectrum analysis software. Also described are the gamma-scanning ...

Energy Technology Data Exchange (ETDEWEB)

The work reported here concerns the evolution of the shape of a coherent, cubic precipitate as it grows by coarsening. The work was motivated by the need to explain recent experimental observations that show that cuboidal ..gamma.. Ni/sub 3/Al precipitates in Ni-Al alloys resist coarsening and decompose into doublets of parallel rectangular plates and octets of small cubes. The theoretical model assumes a precipitate of cubic phase with negative elastic anisotropy, and neglects any difference between the elastic constants of the precipitate and the matrix. The elastic energy of the precipitate is then calculated as a function of its morphology, including the possibility of decomposition into doublets or octets of discrete particles. The results show that a cuboidal precipitate with (100) faces and edge length, 2a, is metastable with respect to transition to a doublet of discrete plates, with dimensions a x 2a x 2a, that are separated by the ...

International Nuclear Information System (INIS)

Possibility for using a sodium iodide scintillator as a reference signal source is considered. Experimental data on studying the performance of a gamma thickness gage with an additional scintillator are given. Results of experimental investigations of a thickness gage dummy proved practical expediency of the principle being considered. It is established, in particular, that the device is ready to operate without warm-up with a constant sensitivity, the deviation not exceeding 0.5%, in the ambient temperature range of 15-25 deg C.

International Nuclear Information System (INIS)

The distribution of mass, charge and angular momentum transfer among the products of 54-Fe (255 MeV) ions collisions with the 106 Cd target have been studied. The energy level schemes for 92-Mo, 60-Ni, 96-Ru and 56-Fe are presented. The production yields of different isotopes were also measured. 1 ref., 14 figs.

Energy Technology Data Exchange (ETDEWEB)

New measurements of relative gamma-ray emission probabilities in the decay of [sup 101]Mo and [sup 101]Tc 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)

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.).

CERN Document Server

We propose a method to determine the cosmic mass density Omega from redshift-space distortions induced by large-scale flows in the presence of nonlinear clustering. Nonlinear structures in redshift space such as fingers of God can contaminate distortions from linear flows on scales as large as several times the small-scale pairwise velocity dispersion sigma_v. Following Peacock & Dodds (1994), we work in the Fourier domain and propose a model to describe the anisotropy in the redshift-space power spectrum; tests with high-resolution numerical data demonstrate that the model is robust for both mass and biased galaxy halos on translinear scales and above. On the basis of this model, we propose an estimator of the linear growth parameter beta = Omega^0.6/b, where b measures bias, derived from sampling functions which are tuned to eliminate distortions from nonlinear clustering. The measure is tested on the numerical data ...

Energy Technology Data Exchange (ETDEWEB)

The NIS-6 group at Los Alamos National Laboratory pioneered the development of Tomographic Gamma Scanning and continue to improve its utility in real measurement situations. Building on this experience we report the development of a state of the art TGS system suitable for industrial applications. The image reconstruction and visualization software has been integrated into the familiar Canberra NDA2000 software suite which also handles all other aspects of the data acquisition and management. In this paper we describe the salient design and performance parameters of the system. The application of gamma-ray tomography to safeguards for improved assay accuracy and knowledge confirmation is discussed. In particular we compare and contrast the relative merits of this TGS and a traditional Segmented Gamma Scanner and illustrate how the 3-D visualization of the TGS image can provide valuable additional ...

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 rays from discrete celestial sources.

International Nuclear Information System (INIS)

The energy level schemes of "1"5"2Gd and "1"5"2Sm have been established on the basis of single #gamma#-spectra, and #gamma#-#gamma# coincidence measurements. Ge(Li) detectors were used to study the gamma spectra produced in the EC/#beta#"+ and #beta#"- decays of "1"5"2Eu to "1"5"2Sm and "1"5"2Gd, respectively. Thirteen new transitions are reported and data from eleven coincidence gates enabled five new levels to be suggested. Relative intensities and log ft values were calculated and spin/parities deduced. Comparisons are made with new predictions of the Interacting Boson Model. (orig.).

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.

International Nuclear Information System (INIS)

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 ...

International Nuclear Information System (INIS)

Terminal-differential algorithm for identification of local nonhomogeneities in items under control is developed on the basis of measurements of X-ray or gamma-radiation weakening. The algorithm may be applied by developing radiation schemes of nondestructive control, identifying inadmissible inclusions in the object under study

International Nuclear Information System (INIS)

In the execution of disposal of low and intermediate level radioactive wastes, it is important to evaluate accurately the kind and quantity of each radionuclide in the wastes. For such an evaluation, correlation of non-gamma-emitting nuclides based on gamma-emitting nuclides is recommended and regarded as a partial method. This method necessitates a completion of a highly accurate and reliable nondestructive assay system of gamma-emitting nuclides for partical use. In 1992, in support of the new waste disposal program in Hungary, Paks NPP initiated a waste characterization program to determine the radiological properties of its rad wastes. A segmented gamma scanning system has been set up to measure the gamma-emitting nuclides in 2000 litre low level drums following in-drum compaction. In the framework of the program a radiochemical analysis sub-program was ...

International Nuclear Information System (INIS)

An experimental study was performed in order to study the nuclear structure in odd--odd In isotopes. Low lying nuclear energy levels in "1"1"0In and "1"1"2In were determined from de-excitation #gamma#-rays produced with "1"0"7AG(#alpha#,n#gamma#)"1"1"0In, "1"0"8Pd("6Li,4n#gamma#)"1"1"0In, "1"0"9Ag(#alpha#,n#gamma#)"1"1"2In and "1"1"0Pd("6Li,4n#gamma#)"1"1"2In reactions. In addition, the "1"1"4In energy level structure was investigated with the "1"1"0Pd("7Li,3n#gamma#)"1"1"4In reaction. Properties of de-excitation #gamma#-rays were determined from #gamma#--#gamma# coincidence excitation and angular distribution measurements conducted with Ge(Li) and Ge(intr.) #gamma#-ray detectors. A sequence of intraconnected levels in each of "1"1"0 "1"1"2 "1"1"4In were assigned to the ...

International Nuclear Information System (INIS)

In clinical applications, it is very important to accurately determine the range of a proton beam in a patient. Recently, a prototype prompt-gamma scanning system, called a prompt-gamma scanner (PGS), has been constructed at Hanyang University in Korea with the collaboration of the Korean national cancer center (NCC), based on a series of Monte Carlo simulations. The PGS system is composed of a prompt-gamma collimator, a CsI(Tl) scintillation detector, a multi-channel analyzer (MCA), a precision movement system, and an integrated readout system. The prompt-gamma collimator is designed to effectively shield high-energy neutrons from the proton beam passage and subsequent capture gammas. The PGS system can be used to scan the distribution of the prompt gammas in the patient from the proton beam passage. The distribution of the prompt gammas ...

International Nuclear Information System (INIS)

We have measured the neutron capture and fission cross section of "2"3"3U at the neutron time-of-flight facility n-TOF at CERN in the energy range from 1 eV to 1 MeV with high accuracy by using a high performance 4#pi# BaF_2 Total Absorption Calorimeter (TAC) as a detection device. The method, based on the shape analysis of the TAC energy response, allowing to disentangle between #gamma#'s originating from fission and capture will be presented as well as the first very preliminary results. (authors)

International Nuclear Information System (INIS)

Empirical formulae are proposed for the description of relation between optimum energies minimizing the mean-weighted error of gamma absorption measurement of the thickness of layers in two-layer products with the thickness of every layer from 30 up to 150 mm by carbon. Error of informational parameter approximation with the application of tables does not exceed 10% in case of non-accurate assessment of layers thickness not exceeding 2.5%. Generalized equation is derived which binds main parameters of the task and permits to choose optimum energies with the accuracy sufficient for practical purposes

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.

Energy Technology Data Exchange (ETDEWEB)

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 ...

Energy Technology Data Exchange (ETDEWEB)

Two methods for measuring indoor radon concentrations using activated charcoal have been tested. The first method is the well-known technique with direct gamma-measurements on the exposed canister after the sampling period. The other method uses a thermoluminescence dosemeter placed in the charcoal canister, giving an integrated value of the radon concentration.

International Nuclear Information System (INIS)

Measurement of fission and activation products in the soil or over a plane grass land of a nuclear power station environment is required to find out the long term changes. The inventory of radionuclides in the soil is routinely determined by soil sampling, processing and gamma spectrometry in the laboratory. The method although is proven and accurate is time consuming and largely dependent on homogenous distribution. Therefore, an alternative and rapid method of in-situ gamma spectrometry using portable devices was standardized to determine the concentration of radionuclides in soil, for regular environmental monitoring as well as during emergency condition. The paper presents the methodology, ready to use factors and compares the results of a few measurements made in the environment of Tarapur Atomic Power Station by both in-situ and laboratory methods. (author)

Energy Technology Data Exchange (ETDEWEB)

Short communication.

International Nuclear Information System (INIS)

The possibility to transform the future linear e"+e"-colliders into the #gamma#e and #gamma##gamma# colliders with approximately the same energies and luminosities was shown earlier. Their properties are compared from the point of view of possible physical investigations on them. 10 refs.; 1 tab.

Science.gov (United States)

of the determinant of the parameter covariance matrix for each ... parameter covariance matrix, as obtained from the Markov chains. The basic set ...

Energy Technology Data Exchange (ETDEWEB)

Superparamagnetic MFe{sub 2}{sup 3+}O{sub 4} (M=Mn{sup 2+}, Fe{sup 2+} and Co{sup 2+}) inverse spinel ferrite (ISF) nanoparticles with narrow size distribution having average diameters of 6-8 nm were synthesized by a diol reduction of organic metals and the surface was modified to be hydrophilic by coating with succimer. Magnetic resonance imaging (MRI) contrast enhancement by dipolar coupling defined interactions between the synthesized ISFs and protons in the bulk water was investigated with initial susceptibility, magnetization and anisotropy of the succimer-coated ISFs. The relaxivity ratios, r{sub 2}/r{sub 1}, for MnFe{sub 2}O{sub 4}, Fe{sub 3}O{sub 4} and CoFe{sub 2}O{sub 4} were measured to be 12.2, 23.1 and 62.3, respectively, which demonstrate the potential usefulness of these magnetic nanoparticles as T{sub 2} contrast agents for MRI.

Energy Technology Data Exchange (ETDEWEB)

The temperature dependence of T/sub 1/ spin-lattice relaxation time on /sup 51/V, /sup 69/Ga, /sup 71/Ga and Knight shift on /sup 51/V and /sup 29/Si nuclei in polycrystalline V/sub 3/Si, V/sub 3/Ga, V/sub 3/Ge and in the monocrystal V/sub 3/Si in normal state is investigated. For V/sub 3/Si and V/sub 3/Ga a rapid growth (T/sub 1/T)/sup -1/ is observed with temperature decrease while for V/sub 3/Ge the maximum (T/sub 1/T)/sup -1/ at T approximately equal to 60 K has been found. The temperature dependence peculiarities have been discussed on the basis of theoretical models available and zone structure calculations for A-15 compounds. The T/sub 1/ anisotropy and possibility of its experimental discovery are considered. Anisotropic contribution in (T/sub 1/T)/sup -1/ and contributions of d states of different symmetries into the electron state density at the Fermi level are estimated for V/sub 3/Si from T/sub 1/ measurements.

CERN Document Server

The measurement of the brightness temperature fluctuations of neutral hydrogen 21 cm lines from the Epoch of Reionisation (EoR) is expected to be a powerful tool for revealing the reionisation process. We study the 21 cm cross-correlation with Cosmic Microwave Background (CMB) temperature anisotropies, focusing on the effect of the patchy reionisation. We calculate, up to second order, the angular power spectrum of the cross-correlation between 21 cm fluctuations and the CMB kinetic Sunyaev-Zel'dovich effect (kSZ) from the EoR, using an analytical reionisation model. We show that the kSZ and the 21 cm fluctuations are anti-correlated on the scale corresponding to the typical size of an ionised bubble at the observed redshift of the 21 cm fluctuations. The amplitude of the angular power spectrum of the cross-correlation depends on the fluctuations of the ionised fraction. Especially, in a highly inhomogeneous reionisation model, the amplitude ...

Energy Technology Data Exchange (ETDEWEB)

The magnetic properties of a single crystal of SmNiSn with the orthorhombic {epsilon}-TiNiSi-type crystal structure have been investigated by magnetic susceptibility, magnetization and electrical resistivity measurements from 1.5 K to room temperature. Two anomalies have been found in the magnetic susceptibility, indicating an antiferromagnetic phase transition at T{sub N}=9.4 K and a second transition at 4.4 K. A large magnetic anisotropy has been found at low temperatures in the temperature and field dependencies of magnetic susceptibility and magnetization. Below 80 K, the easy axis of the magnetization is the c-axis. At T=2.0 K, the c-axis magnetization curve exhibits metamagnetic-like behavior at H{sub c}=42 kOe and reaches 0.54 emu/g at H=55 kOe, whereas for the a- and b-axis the magnetization is linear and smaller. The paramagnetic susceptibilities do not follow the Curie-Weiss law suggesting a large van Vleck contribution of the Sm ...

International Nuclear Information System (INIS)

These experiments were performed on the Isocele separator, on-line with the Orsay synchrocyclotron; thulium isotopes were produced by bombarding natural erbium targets with 150nA beam of 157MeV protons. Two Ge(Li) detectors, with resolution of 2.3 and 2.5keV at 1332keV used for #gamma#-ray measurements; conversion electron spectra were measured using a Si(Li) detector. #gamma# spectra, #gamma#-#gamma# coincidence and conversion electron measurements were sufficient to build the flow energy level schemes of the transitional "1"5"8Er and "1"5"6Er nuclei. On both nuclei several quasi rotational bands have been identified. These results are compared with other even erbium isotopes and with the neighboring N=88 and 90 isotones. Comparisons with predictions issued from some classical models are also performed: "1"5"8Er appears as a deformed nucleus very similar to ...

Energy Technology Data Exchange (ETDEWEB)

The in-plane resistivity, in-plane absolute thermopower, and upper critical field measurements are reported for single-crystal samples of YNi{sub 2}B{sub 2}C and LuNi{sub 2}B{sub 2}C superconductors. The in-plane resistivity shows metallic behavior and varies approximately linearly with temperature near room temperature (RT) but shows nearly quadratic behavior in temperature at low temperatures. The YNi{sub 2}B{sub 2}C and LuNi{sub 2}B{sub 2}C single-crystal samples exhibit large transverse magnetoresistance ({approx}6{endash}8{percent} at 45 kOe) in the ab plane. The absolute thermopower S(T) is negative from RT to the superconducting transition temperature T{sub c}. Its magnitude at RT is a few times of the value for a typical good metal. S(T) is approximately linear in temperature between {approx}150 K and RT. Extrapolation to T=0 gives large intercepts (few {mu}V/K) for both samples suggesting the presence of a much larger {open_quotes}knee{close_quotes} than ...

Energy Technology Data Exchange (ETDEWEB)

The young open cluster Berkeley 87 was predicted to be associated with the COS B {gamma}-ray source 2CG 075+00 on the basis of the experimental evidence of the presence of a shock front around the Wolf - Rayet star ST3 placed in the inner part of the cluster. The CGRO phase-1 data confirm this identification. Protons accelerated at the shock boundary can produce {pi} deg. via p-p interactions and then {gamma}-rays. With the measured flux F{sub {gamma}} (E > 100 MeV) {approx_equal} 9x10{sup -7} ph cm{sup -2} s{sup -1} and the power-law proton spectrum with spectral index {gamma} = 2, the cosmic-ray-energy-density in the inner part ({approx} 0.8 pc radius) of Berk 87 is about 100 times greater than that in the vicinity of the Earth. We have calculated {gamma}-ray spectra expected from the decay of {pi}{sup d}eg. produced in p-p interactions. The spectra ...

International Nuclear Information System (INIS)

The University of Virginia's real-time neutron radiography facility was characterized by measurement of the total neutron flux, gold/cadmium ratio, neutron/gamma ratio, and the effective collimar length-to-aperture diameter (L/D) ratio. The real-time neutron imaging system and collimator were further characterized by measuring the modulation transfer function (MTF) of the system. The collimator effectiveness was measured by using the MTF to determine the ''unparallelism'' of the neutron beam. The computer-based image processing system allowed rapid calculation of the MTF and the collimator effectiveness. The results of these measurements, using no collimator and a simple tube collimator, demonstrated the method's ability to determine the effective L/D ratio. The MTF measurement scheme provided a fast, reliable, and reproducible means of monitoring any changes in ...

International Nuclear Information System (INIS)

A combined application of several microtechniques is presented and discussed with the Ti/TiO_2 and Zr/ZrO_2-systems as an example. All measurements were carried out on single grains of technical materials in order to detect and quantify the effect of substrate microstructure on the properties of anodic passive films formed potentiodynamically in 0.5 M H_2SO_4 (dU/dt = 20 mVs"-"1). Anisotropy-micro-ellipsometry (AME) was employed to determine the crystallographic orientation of the substrate grains along with passive film thickness and crystallinity in dependence on the anodization potential. Both the isotropic (amorphous) TiO_2- and the anisotropic (crystalline) ZrO_2-films exhibit a systematic dependence of film thickness on the grain orientation. Local LASER-scanning photocurrent measurements (#lambda#=257 nm) on the same grains likewise show a heterogeneity of the photoelectrochemical reactivity in all cases. This is ...

British Library Electronic Table of Contents (United Kingdom)

Summary Objective- Gamma-glutamyltransferase (GGT) has been reported to be useful in predicting cardiovascular disease. Arterial stiffness measured by brachial-ankle pulse wave velocity (baPWV) is not only a marker of vascular damage but a significant predictor of cardiovascular events. Gender difference has been reported in the association between GGT and baPWV. We assessed, therefore, the association between GGT and baPWV in a large population and determined whether there was gender difference. Design- This cross-sectional study was conducted at the Asan Medical Centre, Seoul, Republic of Korea. Subjects and measurements- Serum GGT, baPWV and conventional risk factors were measured in 10 988 apparently healthy subjects (7248 men, 3740 women) who participated in a routine health screening...

CERN Document Server

We compute QCD corrections to the production of a ttbar pair in association with a hard photon at the Tevatron and the LHC. This process allows a direct measurement of the top quark electromagnetic couplings that, at the moment, are only loosely constrained. We include top quark decays, treating them in the narrow width approximation, and retain spin correlations of final-state particles. Photon radiation off top quark decay products is included in our calculation and yields a significant contribution to the cross-section. We study next-to-leading order QCD corrections to the ppbar -> ttbar+gamma process at the Tevatron for the selection criteria used in a recent measurement by the CDF collaboration. We also discuss the impact of QCD corrections to the pp -> ttbar+gamma process on the measurement of the top quark electric charge at the 14 TeV LHC.

Energy Technology Data Exchange (ETDEWEB)

The production of three vector bosons in {gamma} {gamma} collisions studying the reactions {gamma} + {gamma} {yields} W{sup +} + W{sup -} + Z{sup 0} and {gamma} + {gamma} {yields} W{sup +} + W{sup -} + {gamma}. 12 refs., 4 figs., 2 tabs.

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 ...

Energy Technology Data Exchange (ETDEWEB)

Two aspects of the deformation behavior of magnesium sheets are the subject of this paper. First it will give a mechanical characterization of a commercial magnesium with a focus on the anisotropy and the possible microstructural causes of this behavior. The rolling process will be part of the second aspect. The aim is to show the influence of the parameters on the microstructure and texture and how this could affect the anisotropy in the rolled sheets. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Energy Technology Data Exchange (ETDEWEB)

Magnetic field, thickness and magnetic forming effect on general mode and quantitative parameters of the domain structure (DS) of ferrite-garnet (EuEr)/sub 3/(FeGa)/sub 5/O/sub 12/ monocrystalline plates (111) is investigated. Field interval of circle (cone) and ring domain stability is determined. It is shown that DS of ferrite-garnet crystals with uniaxial an6sotropy has some peculiarities, that can be explained by cubic anisotropy effect.

Energy Technology Data Exchange (ETDEWEB)

The measurements of the L X-ray intensity ratio I(L{alpha})/I(L{beta}), I(L{alpha})/I(L{gamma}), I(L{alpha})/I(L{iota}), I(L{beta})/I(L{gamma}) and I(L{iota})/I(L{gamma}) for elements Dy, Ho, Yb, W, Hg, Tl and Pb were experimentally determined both by photon excitation, in which 59.5 keV {gamma}-rays from a filtered radioisotope {sup 241}Am was used, and by the radioactive decay of {sup 160}Tb, {sup 160}Er, {sup 173}Lu, {sup 182}Re, {sup 201}Tl, {sup 203}Pb and {sup 207}Bi. L 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 calculated theoretical values. Theoretical values of the I(L{alpha}/L{beta}), I(L{alpha}/L{gamma}), I(L{alpha}/L{iota}), I(L{beta}/L{gamma}) and I(L{iota}/L{gamma}) intensity ratios were calculated using theoretically ...

International Nuclear Information System (INIS)

Development of food preservation and processing techniques by radiation was performed. Gamma irradiation at 2-10 kGy is considered to be an effective method to control pathogenic bacteria in species including Escherichia coli O157:H7. Gamma irradiation at 5 kGy completely eliminated pathogenic bacteria in beef. Gamma irradiation at such doses and subsequent storage at less than 4 deg C could ensure hygienic quality and prolong the microbiological shelf-life resulting from the reduction of spoilage microorganisms. Gamma irradiation on pre-rigor beef shortens the aging-period, improves tenderness and enhances the beef quality. And, a new beef processing method using gamma irradiation, such as in the low salt sausage and hygienic beef patty was developed. Safety tests of gamma-irradiated meats(beefs: 0-5 kGy; porks: 0-30 kGy) in areas such as genotoxicity, acute ...

International Nuclear Information System (INIS)

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, ...

International Nuclear Information System (INIS)

The plans for the CERN LHC heavy ion program in 2010 are for collisions of lead ions during the month of November at an energy about half of the final 5.5 TeV/nucleon. The advanced preparations are mostly for extrapolations of the measurements at the maximum energy previously available, Au + Au at 0.2 TeV/nucleon. Because of the large increase in energy, surprises can be expected. One new feature made possible by the increased energy and the excellent muon energy resolution of CMS will be the study of the yields of the excited states of the upsilon meson as a function of angle and centrality. Although the main emphasis will be on the QGP formed by the overlapping parts of the Pb ions, the spectator parts and the electromagnetic field outside of the ions, #gamma#-Pb and #gamma##gamma#, are also important.

Energy Technology Data Exchange (ETDEWEB)

The energy level schemes of /sup 192/Os and /sup 192/Pt have been established on the basis of ..gamma..-..gamma.. coincidence studies using a dual parameter data collection system. Ge(Li) detectors were employed to study the gamma spectra produced in the E.C. and ..beta../sup -/ decays of /sup 192/Ir to /sup 192/Os and /sup 192/Pt, respectively. Thirteen new transitions and three new levels at 1146.95, 1237.35 and 1913.76 keV are suggested. Relative intensities from singles measurements, branching ratios, ..cap alpha..(K) and log ft values were calculated and multipolarities, spins and parities deduced. Comparisons are made with predictions of the Interacting Boson Model calculated on the basis of an O(6) to SU(3) transition.

CERN Document Server

Using about $226\\times 10^6$ $\\jpsi$ events and $106\\times 10^6$ $\\psi^{\\prime}$ events collected with the BESIII detector at the BEPCII $e^+e^-$ collider, the Dalitz plot of $\\etap \\to \\eta \\pi^+ \\pi^-$ decay is studied, the direct measurement of $a^{0}_{0}(980)-f_{0}(980)$ mixing is performed, $X(2120)$ and $X(2370)$ are observed in the $\\pi^+\\pi^-\\eta^\\prime$ invariant mass spectrum, $\\psi^{\\prime}\\to\\gamma\\pi^0$ and $\\psi^{\\prime}\\to\\gamma\\eta$ are observed for the first time, and the decays $\\chi_{cJ}\\to\\gamma V$ ($V=\\phi$, $\\rho^0$, $\\omega$) are studied.

Energy Technology Data Exchange (ETDEWEB)

The HEU and LEU fuel elements used in the ORR whole-core demonstration were gamma-scanned to determine the axial distribution of the {sup 140}La and {sup 137}Cs activities. Analysis of this data is now complete. From the {sup 140}La activity distributions cycle-averaged powers were determined while the {sup 137}Cs data provided a measure of the final {sup 235}U burnup in the fuel elements. A method for calculating correction factors for activity gradients transverse to the fuel element axis is presented and is applied to the first mixed core used in the demonstration during the gradual transition to an all LEU core. Results based on the gamma-scanning of the LEU fuel followers are also presented. Improved burnup calculations against which the experimental results are to be compared are now in progress. 7 refs., 21 figs., 3 tabs.

Energy Technology Data Exchange (ETDEWEB)

At future {gamma} {gamma} colliders a massive production of tt-bar pairs is possible. This would allow a detailed investigation of the interactions involving the top quark. The authors propose some correlations which are sensitive to tt-bar final state interactions and compute the QCD and standard model Higgs boson contributions to these correlation. QCD-induced transverse polarization of top quarks is found to be sizeable and measurable at a high-energy e{sup +} e{sup -} collider with an integrated luminosity of 10(fb){sup -1} which is converted into a photon collider by backscattering of laser photons. 16 refs.

International Nuclear Information System (INIS)

A new acquisition and evaluation procedure has been introduced for the measurement of time-dependent processes in gamma-ray spectrometry, in order to extract more information, including half-lives, from the data recorded during acquisition and to enable a more comprehensive analysis of the results. These advanced, off-line data evaluation techniques improve the selectivity and the background subtraction and make it possible to estimate the important analytical parameters (e.g., half-lives) more accurately than with the usual decay curve fitting method. (author)

International Nuclear Information System (INIS)

We report on measurements of radiation hardness of the plastic scintillating fiber SCSF-81. Fibers were irradiated with "6"0Co #gamma#-rays and fast neutrons up to 105 Gy and up to 5 x 1013 n/cm"2, respectively. Deterioration of the attenuation length of the scintillating fiber was studied. Some significant deterioration was observed at the integrated dose of about 1 x 103 Gy and at the integrated neutron flux (neutron fluence) of about 1 x 1012 n/cm"2 for #gamma#-ray and neutron irradiation, respectively. (author).

Energy Technology Data Exchange (ETDEWEB)

Wood-plastic composites (WPC) have been prepared with five low-grade woods, native to Syria, using three monomer systems; acrylamide, butylmethacrylate, and styrene, with methanol as the swelling solvent. Polymerization was induced at various radiation doses (10, 20, and 30 kGy) at a dose rate of 3.5 kGy/h using a {sup 60}Co gamma radiation source. Some physical properties of WPC, namely polymer loading and compression strength have been measured. The polymer loading decreases approximately with increasing density of the wood species used.

International Nuclear Information System (INIS)

Wood-plastic composites (WPC) have been prepared with five low-grade woods, native to Syria, using three monomer systems; acrylamide, butylmethacrylate, and styrene, with methanol as the swelling solvent. Polymerization was induced at various radiation doses (10, 20, and 30 kGy) at a dose rate of 3.5 kGy/h using a "6"0Co gamma radiation source. Some physical properties of WPC, namely polymer loading and compression strength have been measured. The polymer loading decreases approximately with increasing density of the wood species used. (author)

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

\\lhcb is one of the four major experiments at the Large Hadron Collider (\\lhc) at CERN. It is custom built to look for CP violation and New Physics in rare decays of heavy flavour hadrons, like the B and D systems. Rare decays that occur via loop diagrams provide a way to probe New Physics at energy scales much higher than can be probed by direct production in experiments. In this article, the \\lhcb prospects for such measurements with exclusive decays of the type $B \\to \\Xs \\gamma$ and $B \\to X_{s} l^{+} l^{-}$ are presented.

Energy Technology Data Exchange (ETDEWEB)

Applying a total energy absorption {gamma}-ray detector composed of 12 bricks (5x5 cm{sup 2}, 7.5 cm thick) of Bi{sub 4}Ge{sub 3}O{sub 12}(BGO) scintillators, the absolute measurement of capture cross sections for Au and Sb has been made in an energy region between 0.01 eV and 10 eV using the linac time-of-flight method. Incident thermal neutron flux was absolutely determined by using the BGO detection system with a Sm sample. To extend the neutron flux measurement from the thermal neutron region to higher neutron energy, the {sup 10}B(n, {alpha} {gamma}) reaction was applied. Absolute capture yield for the relevant capture sample was obtained by the saturated capture yield at a large resonance of the sample. Gold was selected to investigate the application of the BGO detection system to the absolute measurement of the capture cross sections, since the {sup 197}Au(n, ...

International Nuclear Information System (INIS)

The research performed during this reporting period (9/1/84 to 8/31/85) resulted in: (1) publication of three papers; (2) presentation of an invited paper to the conference on ''Neutron-Nucleus Collisions: A Probe of Nuclear Structure''; (3) presentation of three contributed papers at APS meetings; and (4) preparation of three manuscripts, two of which are in the process of internal review at the Oak Ridge National Laboratory and are included with this report, and the third is being typed as this report is being written. The publications and papers deal with topics in both nuclear structure and astrophysics. Our efforts to study the systematic behavior of the optical model potential in the energy region just above neutron binding has been made substantially more reliable with the publication of a paper which discusses the accuracy of the methods used to average the measured scattering matrix. In the area of stellar nucleosynthesis, comparison of our model ...

International Nuclear Information System (INIS)

Measurements of gamma-ray spectra, following the thermal neutron fission of "2"3"5U have been made using a high purity germanium detector at the University of Massachusetts Lowell (UML) Van de Graaff facility. The gamma spectra were measured at delay times ranging from 0.2 s to nearly 10000 s following the rapid transfer of the fission fragments with a helium-jet system. On the basis of the known gamma transitions, forty isotopes have been identified and studied. By measuring the relative intensities of these transitions, the relative yields of the various precursor nuclides have been calculated. The results are compared with the recommended values listed in the ENDF/B-VI fission product data base (for the lifetimes and the relative yields) and those published in the Nuclear Data Sheets (for the beta branching ratios). This information is particularly useful for ...

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 ...

CERN Document Server

Polarization measurements in the X-ray and gamma-ray energy range can provide crucial information on massive compact objects such as black holes and neutron stars. The Polarized Gamma-ray Observer (PoGO) is a new balloon-borne instrument designed to measure polarization from astrophysical objects in the 30-100 keV range, under development by an international collaboration with members from United States, Japan, Sweden and France. To examine PoGO's capability, a beam test of a simplified prototype detector array was conducted at the Argonne National Laboratory Advanced Photon Source. The detector array consisted of seven plastic scintillators, and was irradiated by polarized photon beams at 60, 73, and 83 keV. The data showed a clear polarization signal, with a measured modulation factor of $0.42 \\pm 0.01$. This was successfully reproduced at the 10% level by the computer simulation ...

Energy Technology Data Exchange (ETDEWEB)

In Sweden there is a demand for a method of measuring radon in dwellings with high accuracy and at a low cost. A method of determining radon concentration (Bq.m/sup -3/) in dwellings has been developed at the Swedish National Testing Institute. A plastic canister containing activated charcoal has been tested in a radon chamber (volume 20 m/sup 3/) to determine the effects of relative humidity, temperature and exposure time. The activated charcoal in the canister adsorbs radon from the air surrounding the canister. The radon concentration is determined by counting the gamma rays from the decay of radon and daughters. The theory and preliminary results from calibrations and field measurements are reported.

CERN Document Server

First measurements of inclusive Z production cross sections in muon and electron decay channels at 7 TeV are presented for proton-proton collisions in the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC). The comparison of the kinematic quantities as well as the studies of selection efficiencies demonstrate a good agreement between simulated events and current data. The measured inclusive cross section for Z($\\gamma^{*}$) production agrees with NNLO QCD cross section calculations and current parton distribution functions.

International Nuclear Information System (INIS)

The nuclei "8"1Zr and "8"5Mo with T_z=1/2 have been reinvestigated via their #beta#-delayed proton emissions with p-#gamma# coincidence measurement. The half-life of "8"1Zr has been measured to be 5.3#+-#0.5 s, which agrees with one of the two previous values. For "8"5Mo, the measured half-life is 3.2#+-#0.2 s, which revises the previous value. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The proton beam has a unique advantage over the electron and photon beams in that it can give very high radiation dose to the tumor volume, while effectively sparing the neighboring healthy tissue and organs. For the clinical application of the proton beam, it is very important to confirm the location of the proton beam in the patient, preferentially during the treatment. It has been suggested that the range of the proton beam in the patient can be determined by measuring prompt gammas from the proton beam passage. Recently, a prototype prompt-gamma scanning system has been constructed and tested using experimental and therapeutic proton beams. The measurement results for the proton beams of 70 . 230 MeV showed that a clear correlation exists between the distribution of the prompt gammas and the proton beam range. The scanning method, however, is not suitable for the upcoming ...

International Nuclear Information System (INIS)

In this experiment, we measured the detection efficiency of gamma-scanning system of Irradiated Materials Examination Facility (IMEF) in Korea Atomic Energy Research Institute(KAERI) for the spent PWR fuel and activity known sources with high activity. We measured the absolute detection efficiency of gamma scanning system of IMEF to the "1"3"7Cs-source with 10.4 GBq and "6"0Co source with 25.9 GBq High-activity sources as standard sources, and a fuel burned in the KORI -1 reactor of the Kori Nuclear power plant. In analyzing, we used three peeks those were the 661.64 keV peak form "1"3"7 Cs 1173.23 and 1332.51 keV"6"0 Co sources, and 14 peaks of "1"3"4Cs and "1"5"4Eu on the spent fuel gamma spectrum which are in the energy range from 500 to 1,600 keV. We find second order equations for detection efficiency by using our experimental results. The equation show that the detection ...

CERN Document Server

We discuss the minimum requirements for a neutrino beta beam if theta_13 is discovered by an upcoming reactor experiment, such as Double Chooz or Daya Bay. We require that both neutrino mass hierarchy and leptonic CP violation can be measured to competitive precisions with a single-baseline experiment in the entire remaining theta_13 range. We find that for very high isotope production rates, such as they might be possible using a production ring, a (B,Li) beta beam with a gamma as low as 60 could already be sufficient to perform all of these measurements. If only the often used nominal source luminosities can be achieved, for example, a (Ne,He) beta beam from Fermilab to a possibly existing water Cherenkov detector at Homestake with gamma \\sim 190-350 (depending on the Double Chooz best-fit) could outperform practically any other beam technology including wide-band beam and neutrino factory.

Energy Technology Data Exchange (ETDEWEB)

Mass and charge distributions of products from fission of sup(242m)Am induced by thermal neutrons have been investigated by means of the semiconductor spectrometry of ..gamma.. radiation from a mixture of non-separated fragment nuclei. Specimens of the fissible material have been irradiated in the vertical experimental channel of the research reactor then the measurements have been performed with calibrated semiconductor detectors. Three experiments with substantially different irradiation times have been performed to expand the nomenclature of the investigated fission products. The spectra of ..gamma.. radiation from the mixture of fission products, and time dependences of the counting rates at the total absorption peaks have been handled with computers. The obtained yields are compared with data of previous investigations performed with different experimental methods, as well as with the calculated one.

Energy Technology Data Exchange (ETDEWEB)

X-ray photoelectron spectroscopy measurements indicate that the Ce{sup 3+} like fraction in {gamma}-Al{sub 2}O{sub 3} supported CeO{sub 2} can be decreased by the incorporation of La{sup 3+}. If La{sup 3+} is incorporated into the {gamma}-Al{sub 2}O{sub 3} before CeO{sub 2} is added, a higher CeO{sub 2} dispersion and a greater range of reversible reducibility of the CeO{sub 2} may also be obtained. These changes offer potential for improvement in the oxygen storage capacity provided by CeO{sub 2} in three-way catalysts. The actual effect of La{sup 3+} incorporation on the activity and durability of a Pt catalyst is assessed by a combination of temperature programmed reduction and flow reactor measurements.

Energy Technology Data Exchange (ETDEWEB)

The authors study the processes {gamma}e {r{underscore}arrow} {gamma}e and {gamma}{gamma} {r{underscore}arrow} {gamma}{gamma}, in the context of the proposal for Weak Scale Quantum Gravity (WSQG) with large extra dimensions. With an ultraviolet cutoff M{sub S} {approximately} 1 TeV for the effective gravity theory, the cross sections obtained for these processes at the Next Linear Collider (NLC), with the e{gamma} an {gamma}{gamma} options, deviate from the predictions of the Standard Model significantly. The results suggest that, for typical proposed NLC energies and luminosities, the predictions of WSQG can be tested in the range 1 TeV {approx{underscore}lt} M{sub S} {approx{underscore}lt} 10 TeV, making e{gamma} an {gamma}{gamma} colliders important tools for probing WSQG.

International Nuclear Information System (INIS)

For the first time a comprehensive level and decay scheme has been obtained for a T=(5/2) nucleus in the s-d shell ("2"7Na) by using a radioactive beam and target. Particle-#gamma# and p-#gamma#-#gamma# coincidences were measured following the "1"4C("1"4C,p#gamma#)"2"7Na reaction at E_l_a_b=22 MeV. The results do not support an inversion of the 2s_1_/_2 and 1d_5_/_2 orbitals, as previously proposed for T_z#>=#3, but they do suggest an increased N=16 gap between the 2s_1_/_2 and 1d_3_/_2 orbitals due to the neutron excess. A consistent interpretation of the level scheme in terms of the s-d shell model using the USD Hamiltonian is possible below 4 MeV, but differences increase at higher excitation energies. Another interpretation is that the influences of both the p_1_/_2 and f_7_/_2 intruder orbitals increase simultaneously with increasing T, an effect not included in the USD Hamiltonian.

Energy Technology Data Exchange (ETDEWEB)

Concerning the gamma emitters, the only analysis on soils put in evidence the presence of cesium-137 ({sup 137}Cs), that does not come from the cyclotron functioning but from past man action as the Chernobylsk accident and the nuclear weapon tests in atmosphere. Independently of the functioning of the installation, we observe an increase of the ambient gamma radiation only near radioactive waste storage. It results of the storage of the former cyclotron elements. The induced increase is moderated because at 5 meters the values do not exceed the background noise. In relation with the functioning of the installation an increase of the ambient gamma radiation is noticed. Two causes are to considered: the release of radionuclides in atmosphere with gaseous effluents and the radiance of radiation sources inside the building. After the stopping of the installation (48 h at least), no increase of gamma ...

CERN Document Server

In this work we develop a new propagation model for the Galactic cosmic rays based on the GALPROP code, including contributions from dark matter annihilation. The model predicts compatible Galactic diffuse $\\gamma$ ray spectra with EGRET data in all sky regions. It also gives consistent results of the diffuse $\\gamma$ ray longitude and latitude distributions. Further the results for B/C, $^{10}$Be/$^9$Be, proton, electron and antiproton spectra are also consistent with cosmic ray measurements. In the model we have taken a universal proton spectrum throughout the Galaxy without introducing large fluctuation for the proton energy loss is negligible. The dark matter annihilation signals are `boosted' after taking the contribution from subhalos into account. Another interesting feature of the model is that it gives better description of the diffuse $\\gamma$ rays when taking the source distribution ...

International Nuclear Information System (INIS)

The evolution of Bianchi type-I and type-IX universes for a theory of gravity with an #epsilon#R"2 term added to the usual Lagrangian is considered. As in the spatially flat Robertson-Walker case considered previously by others, inflation is found to occur. For any amount of initial anisotropy, the anisotropy decays quickly relative to the length of the inflationary epoch, and the amount of expansion is enhanced by the anisotropy. The exceptions are Bianchi type-IX universes near or at isotropy. In these cases a wide range of initial parameters causes the universe to recollapse, thus reducing the phase space in which inflation can occur. The diagonal metric is shown to be the most general form in the R"2 theory for both Bianchi type-I universes with a perfect fluid and vacuum Bianchi type-IX models.

Energy Technology Data Exchange (ETDEWEB)

Within the framework of the Bianchi type-IX homogeneous space, we set up a system of coupled equations for the cosmic scale factors, scalar field, and radiative energy density. At the tree level, the equations are written in a self-consistent, Hartree-Fock form. For phi/sup 4/ theory, the system of nine first-order differential equations is solved numerically for a varying ratio of the energy of anisotropy to the vacuum energy. As the vacuum energy increases, there appears to be less reheating, since the energy of anisotropy is more efficiently converted into isotropic expansion. If the energy of anisotropy is large enough, the inflationary phase is prevented. In this case, a series of cosmological phase transitions will take place each time the square of the effective mass changes its sign.

Energy Technology Data Exchange (ETDEWEB)

Car weight corresponds directly to fuel consumption and driving performance. So in order to improve the fuel efficiency and performance of a car the weight has to be reduced. Magnesium as a light metal offers a wide range of weight saving opportunities, especially Magnesium wrought alloys with their improved mechanical properties have a high potential for structural applications. Mechanical properties in terms of their quality and anisotropy are dependent on the microstructure of the material and can be characterized by their degree of inhomogeneity, their grain size distribution and their crystallographic texture. Therefore the orientation distribution of grains, the grain size, its size distribution, the chemical composition (precipitates) itself influence the mechanical parameters and their anisotropy. In this presentation first results of mechanical anisotropy are given: differences in yield stress, r-values and their ...

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 ...

Energy Technology Data Exchange (ETDEWEB)

TiH{sub 2} and TiD{sub 2} thick targets were bombarded with 100 to 200 keV protons or deuterons. Evidence for nuclear reactions was obtained by means of a surface barrier particle detector. Deuteron irradiation of TiD{sub 2} produced these observations: copious {approx}2.5 MeV neutrons and {approx}3 MeV protons from direct D-D reactions; gamma rays from p,{gamma} and n,{gamma} reactions; {approx}14 MeV protons from the secondary d({sup 3}He, p){alpha} reaction; and a signal between {approx}6-12 MeV that Kasagi et al. has tentatively identified as protons from the fusion of three deuterium nuclei. However, this signal has in it a strong interference signal from either neutrons or gamma rays that directly deposit energy in the detector. This interference spectra was measured by placing a thick absorber in front of the detector that stops up to 20 MeV protons, but not ...

International Nuclear Information System (INIS)

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

International Nuclear Information System (INIS)

Three possibilities to observe the Higgs-top interaction at future #gamma##gamma#-colliders are discussed: a) associated Higss production via the #gamma##gamma##->#tanti tH reaction, b) Higgs obliged radiative correction to the #gamma##gamma##->#tanti t channel, c) Higgs resonance production via #gamma##gamma##->#H#->#ZZ. The results obtained show windows of the Higss mass where the Yukawa interaction of the Higss with the top quark can be studied at #gamma##gamma#-colliders. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The first meeting on e{gamma}/{gamma}{gamma} colliders was held on September 28 and 29, 1993, at the National Laboratory for High Energy Physics. After general remarks were delivered, lectures were given on QED in intense laser field, photon linear collider, laser focusing, luminosity distribution in the e{gamma}/{gamma}{gamma} colliders, QCD correction for {gamma}{gamma}{yields}H, radiation correction for e{gamma}/{nu}W process, SUSY particle production at the e{gamma} and {gamma} gamma colliders, formation of e{sup *} in e{gamma} collision, and general remarks on the theory. Discussion was carried out on `Where are we going from here?` In this book, the gists of the lectures are collected. (K.I.).

Science.gov (United States)

The gadolinium isotopes are interesting for reactor applications as well as for medicine and astrophysics. The gadolinium isotopes have some of the largest neutron capture cross sections. As a consequence they are used in the control rod in reactor fuel assembly. From the basic science point of view, there are seven stable isotopes of gadolinium with varying degrees of deformation. Therefore they provide a good testing ground for the study of deformation dependent structure such as the scissors mode. Decay gamma rays following neutron capture on Gd isotopes are detected by the DANCE array, which is located at flight path 14 at the Lujan Neutron Scattering Center at Los Alamos National Laboratory. The high segmentation and close packing of the detector array enable gamma-ray multiplicity measurements. The calorimetric properties of the DANCE array coupled with the neutron time-of-flight technique enables one to gate on a ...

Energy Technology Data Exchange (ETDEWEB)

This report describes the preliminary thermalhydraulic analysis of HTR-10 steady state full power initial core to provide a benchmark calculation of VHTGR(Very High-Temperature Gas-Cooled Reactors) safety analysis code of GAMMA(GAs Multicomponent Mixture Analysis). The input data of GAMMA code are produced for the models of fluid block, wall block, radiation heat transfer and each component material properties in HTR-10 reactor. The temperature and flow distributions of HTR-10 steady state 10 MW{sub th} full power initial core are calculated by GAMMA code with boundary conditions of total reactor inlet flow rate of 4.32 kg/s, inlet temperature of 250 .deg. C, inlet pressure of 3 MPa, outlet pressure of 2.992 MPa and the fixed temperature at RCCS water cooling tube of 50 .deg C. The calculation results are compared with the measured solid material temperatures at 22 fixed instrumentation positions in ...

International Nuclear Information System (INIS)

This paper reports on Monte Carlo path integral simulations of a Bianchi Type IX cosmology which yield a wave function which reflects the known chaotic dynamics of the classical system and predicts a significant probability for a correlation between large universe volume and large anisotropy.

Science.gov (United States)

To calibrate channels A1 to A4 for particles with Z >= 1, tests were done on the IBIS accelerator at AERE, Harwell, which gave protons up to 3 MeV. ...

Science.gov (United States)

Using bremsstrahlung, the resonance fluorescence yield has been measured for the 1.836-MeV 2/sup +//sub 1/ level in /sup 88/Sr. The observed yield corresponds to a level width GAMMA = 2.94 +- 0.15 meV.

International Nuclear Information System (INIS)

The nuclear shapes of transitional Mo isotopes are calculated by means of a model based on the cranking approximation and the Strutinksy method. The recent experimental results of the high-spin spectroscopy and lifetime measurement of "8"7Mo are studied in detail and explained by the evolution of the #gamma#-deformation with the quasiparticle configurations. The shape calculations with the modified-harmonic-oscillator potential give a critical neutron number N #>=# 47 for the spherical shape of the Mo isotopes. (orig.).

International Nuclear Information System (INIS)

The spectrometric methods and equipment for "2"0"1Pb and "2"0"1Tl activity control in the prepared thallium chloride in industrial production are described. Estimation of thallium-201 activity is carried out in accord with the square of summary photopeak caused by #gamma#-quanta at 167 keV energy. Attenuation is paid to spectrometer calibration. 5 refs.; 2 figs.; 2 tabs.

International Nuclear Information System (INIS)

Airborne lead particulates collected on a membrane filter were determined by the nondestructive X-ray fluorescence method. The gamma/X radionuclide source "2"4"1Am/Ag and a scintillation detector with a NaI/Tl crystal were used for the excitation and detection, respectively, of L X-rays of Pb. One can say, with reference to the obtained results, that the sensitivity and accuracy of the measurement is more than adequate for monitoring the Pb level in air. (author).

Energy Technology Data Exchange (ETDEWEB)

Energy spectra of the Bragg reflection of the Moessbauer ..gamma..-radiation from the /sup 57/Fe/sub 3/BO/sub 6/ weakly ferromagnetic monocrystal are studied. A strong effect of the interference transitions in iron nuclei, being in non-equivalent positions, on the spectra form is revealed. The measurement results are compared with theoretical calculations.

Energy Technology Data Exchange (ETDEWEB)

Radiation degradation of polycarbonate (PC) and polybutylene terephthalate (PBT) used as cable connector was evaluated using DSC, TGA, and mechanical properties. Glass transition temperature, melting temperature, 5% weight loss temperature, elongation at break, and tensile strength measurements were carried out for each of {gamma}-ray irradiated samples. In the results of those analyses, PC has radiation resistance better than PBT as a cable connector material.

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)

The first radon soil gas survey in Serbia, using passive detectors (SSNTD, CR-39), was carried out in June 2005 at field sites in Niska Banja town. The aim of the survey was to identify risk zones characterised by high levels of this radioactive gas. Radon measurements were made at the depth of 50 cm, in the ground according to a systematic grid pattern. Furthermore, at all 48 measurement points, the surface gamma dose rates in the air was also measured at the same locations and soil samples were collected for gamma spectrometric analysis for the radionuclides "2"2"6Ra, "2"2"8Th and "4"0K. Radon concentrations were found to range from 1270 to 155000Bqm"-"3 with an average of 33765Bqm"-"3 and a median value of 12626Bqm"-"3. The geometrical mean value and geometrical standard deviation were calculated as 16160Bqm"-"3 and 3.5Bqm"-"3, respectively. Gamma dose rate ...

International Nuclear Information System (INIS)

To dispose the radioactive waste drums, the waste form's integrity and the nuclides inventories must be assured according to the national and site waste acceptance criteria. Because they might be would gravely affected the performance objectives of disposal site. Our national regulation for the waste inventory related to 'Radioactive Waste Acceptance Criteria' requires that the activities of 13 nuclides and gross #alpha# must be measured and the 95 % of nuclides incorporated in the drum must be identified. It is very difficult to measure the radioactivity with accuracy from the regulated waste drum(200L), and have a large error in the analysis results. In present, there are two system, SGS (Segmented Gamma Scanning System) and TGS (Tomographic Gamma Scanning System) for the analysis of radionuclides from the waste drums. In general, it is known that the accuracy of TGS is below 20 % and that of SGS is ...

International Nuclear Information System (INIS)

Safety studies related to the disposal of low- and intermediate waste indicate that the long term risk is determined by the presence of long-lived nuclides such as "1"4C, "5"9Ni, "6"3Ni, "9"9Tc, "1"2"9I and the transuranium elements. As most of these nuclides are difficult to measure, the correlation between these critical nuclides and some other easily measurable key nuclides such as "6"0Co and "1"3"7Cs has been investigated for typical waste streams of Paks Nuclear Power Plant (Hungary) and scaling factors have been proposed. An automated gamma-scanning monitor has been purchased and calibrated to determine the gamma-emitting radionuclides. Radiochemical methods have been developed to determine significant difficult-to-measure radionuclides. The radionuclides of interest have been "3H, "1"4C, "9"0Sr, "5"5Fe, "5"9Ni, "9"9Tc, "1"2"9I and TRUs. The measurements ...

International Nuclear Information System (INIS)

The Gamma Physics (GaP) program of physical phenomena investigation is proposed on #gamma#p, #gamma#e and #gamma##gamma# colliders at TeV energies. The program contains specialized software (CompHEP system) created for automation of particle interaction processes calculations in the framework of various gauge models. Preliminary physical results are presented (heavy quark production, W, Z production, supersymmetry etc.), and further software development is suggested. (R.P.) 22 refs., 8 figs., 4 tabs.

Energy Technology Data Exchange (ETDEWEB)

It is noted that the existence of cosmic-ray semidiurnal anisotropy of interplanetary origin has generally been attributed to the symmetrically rising density gradients perpendicular to the solar equatorial plane. An increase in the magnitude of the semidiurnal anisotropy of cosmic rays during the years 1973-1975 by a factor of 2 is in theory expected to be associated with larger magnitudes of the heliolatitudinal density gradients. The distribution of cosmic-ray intensity in the heliolatitude range + or - 7.25 deg obtained using the data of the Deep River neutron monitor is shown not to support the density gradient hypothesis. The presence of symmetrical gradients at higher heliolatitudes, however, cannot be ruled out.

CERN Document Server

The intrinsic decay rate of orthopositronium formed in SiO/sub 2/ powder is measured using the direct 2 gamma correction method such that the time dependence of the pick-off annihilation rate is precisely determined. The decay rate of orthopositronium is found to be 7.0396+or-0.0012(stat.)+or-0.0011(sys.)/ mu s/sup -1/, which is consistent with our previous measurements with about twice the accuracy. Results agree well with the O( alpha /sup 2/) QED prediction, and also with a result reported very recently using nanoporous film.

Energy Technology Data Exchange (ETDEWEB)

This paper presents calculations of the {sup 252}Cf-source-driven noise analysis measurements for subcritical highly enriched uranium metal cylinders using the Monte Carlo code MCNP-DSP. This code directly calculates the noise analysis data from the {sup 252}Cf- source-driven noise analysis method for both neutron and gamma ray detectors. Direct calculation of experimental observables by the Monte Carlo method allows for the benchmarking of the calculational model and the cross sections and for determining the bias in the calculation.

Energy Technology Data Exchange (ETDEWEB)

Neutron capture cross sections of actinides are of great relevance for the Transmutation of Nuclear Waste in Accelerator Driven Systems (ADS) and Generation-IV reactors. The neutron capture cross sections of {sup 237}Np and {sup 240}Pu in the range of 1 eV to 2 keV were measured at the n-TOF facility with a Total Absorption Calorimeter. The data have been analyzed with the SAMMY code. The corresponding covariance matrices have been generated. The final cross sections are presented and compared to the previously existing ones.The n-TOF {sup 237}Np {sigma}(n,{gamma}) is in agreement with the evaluated data files below 300 eV and its is lower by 10 to 15% up to 2 keV. This discrepancy with the evaluated data files is also observed in the capture cross section derived from the transmission measurements of Gressier et al. In the case of the {sup 240}Pu {sigma}(n,{gamma}), the n-TOF ...

Energy Technology Data Exchange (ETDEWEB)

Measurements are presented of indoor radon levels made in a prototype house constructed partly of bauxite waste (red mud) and partly of conventional materials. The mud used contains higher than the average amounts of {sup 226}Ra and {sup 232}Th found in local building materials. The rates of exhalation of radon from the material used in the construction of the house are measured and employed with measured air change rates to make estimates of the average contribution of the various materials to the measured radon levels indoors. There is fairly good agreement between the two. The increment of radon related dose equivalents above background are also estimated and these are combined with previously determined gamma dose equivalents and used as a basis for assessing the acceptability of the practice of using red mud as a building material. (author)

International Nuclear Information System (INIS)

A miniature device is described for measuring integral potential alpha energy concentration of radon daughter products (Csub(Rn)) for personnel and stationary dosimetry. The measuring apparatus consists of an air sampler, filters and TLD detectors. CaSO_4:Dy-teflon pellets were used as the detectors which registrate #gamma# radiation as well. The TLD-effect dependence on the potential alpha energy, as well as the fading of the detectors at 20-60 deg C after 170 hrs operation are presentd. The fading up to 40 deg C has been found to be negligible. The dosimeter may be used to measure Csub(Rh) starting with the 10"5 MeVxh/1 threshold, the accuracy being not worse than +-30%.

Energy Technology Data Exchange (ETDEWEB)

Short communication

International Nuclear Information System (INIS)

We study the signals for composite vector leptoquarks in e"+e- colliders (CERN e"+e- collider LEP II, Next Linear Collider, and CERN Linear Collider) through their effects on the production of jet pairs, as well as their single and pair productions. We also analyze their production in #gamma#e and #gamma##gamma# collisions.

International Nuclear Information System (INIS)

The dependence of the efficiency of a coaxial IGC-30 Ge detector on the direction of gamma quanta entry, their energy and the distance from the source is examined. A set of point sources QCR-2 (Amersham, UK) has been used which is arranged consecutively in two perpendicular planes passing through the detector axis, at a distance of 0.1 - 1.3 m (pace 0.1) from its geometric centre for 16 different angles in every plane. Dependence curves of the efficiency on the angle of gamma-quanta hits are obtained for energies 60, 81, 122, 356, 662, 834, 1173 and 1332 keV. Changes in efficiency connected with spatial dividing ability are found out. Using the least squares' method the expected spatial distribution of efficiency is examined with a level of authenticity P > 0.9. The possible causes for the efficiency change and its possible effect on the measurements' precision are discussed. (author).

Energy Technology Data Exchange (ETDEWEB)

The current status of rare B decays is reviewed based on recent observation of the penguin-diagram decay B {yields} K{sup *}{gamma} at CLEO. Rare B decays provide valuable information on the Standard Model parameters, and also could be a source of direct CP violation. It is emphasized that new physics beyond the Standard Model can appear in rare B decays, in some cases more drastically than in the CP Asymmetry of the B system. Inclusive measurement of the radiative transition b {yields} s{gamma} is promising. Hadronic penguin modes are very close to being observed at CLEO, and a discovery might be just around the corner. (author). 48 refs., 6 figs., 4 tabs.

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 ...

Energy Technology Data Exchange (ETDEWEB)

Fuel elements used in the ORR whole-core LEU fuel demonstration have been gamma-scanned to determine axial distributions of UZLa and TXCs fission product activities. This data has been analyzed to determine cycle-averaged fuel element powers, residual STVU masses, and burnups of discharged fuel elements. Methods used to analyze the data are discussed and results are presented for the LEU fuel elements. Measured and calculates fuel element powers agree to within 5%, residual STVU masses to within 2%, and burnups to within 3%. These results are somewhat preliminary and await improved burnup calculations and independent calibration data to be based on the destructive analyses of a number of irradiated fuel elements. 4 refs., 7 figs., 3 tabs.

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)

Irradiation processing of food in the prepackaged form may affect chemical and physical properties of the plastic packaging materials. The effect of #gamma#-irradiation doses (2.5-10.0 kGy) on polypropylene (PP)-based retortable food packaging materials, were investigated using Fourier transform infrared (FTIR) spectroscopic analysis, which revealed the changes happening to these materials after irradiation. The mechanical properties decreased with irradiation while oxygen transmission rate (OTR) was not affected significantly. Colour measurement indicated that Nylon 6 containing multilayer films became yellowish after irradiation. Thermal characterization revealed the changes in percentage crystallinity.

Energy Technology Data Exchange (ETDEWEB)

The effective fraction of delayed photoneutrons ({beta}{sup ph}) has been theoretically defined and experimentally determined in various different configurations of the LWR-PROTEUS critical facility. The peculiarity lies in the fact that the reactor has D{sub 2}O in only one of the four fuelled zones, thus D({gamma},n)H reactions take place mainly in this region. The work is divided into three parts. The first part is devoted to the description of the LWR-PROTEUS facility and to the measurements of {beta}{sup ph}. These experimental values are derived from standard inverse-kinetics analysis of neutron flux decay experiments for each of seven different configurations, with nine additional groups of neutron precursors to account for photoneutron effects. In the second part, the coupled neutron and gamma Boltzmann equations are reduced to exact point kinetics equations using the photon infinite-velocity approximation, and then ...

International Nuclear Information System (INIS)

There are several on-going projects of e"+e"- colliders. If they are constructed, we can convert them into photon-photon (#gamma#-#gamma#) colliders by converting electron beams into #gamma# beams, irradiating laser beams just before the interaction point. In this report we discuss the technical issues on the accelerator.