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as for direct energy conversion in specialized direct electrical energy conversion plants. Figure 1. An energetic (~163KeV) proton and a 11boron nucleus fuse ...

UK PubMed Central (United Kingdom)

This paper describes the problems and solutions in using 18 MeV linear accelerator, with minimum 6 MeV electron capability, for total skin irradiation for mycosis fungoides. The 6 MeV electron energy...Full Text Available

International Nuclear Information System (INIS)

We describe the continued development of a portable, real-time neutron spectrometer. The spectrometer is composed of two distinct detector systems: a Helium 3 gas filled proportional counter for the lower neutron energy interval between 20 KeV and 2 MeV and a bulk silicon solid state detector for the higher energy interval between 2 MeV and 500 MeV. Modeling and experimental results with mono-energetic neutron beams are reported.

International Nuclear Information System (INIS)

The spectral energy-dependence of the radiation-induced ESR signal has been studied in ovine cortical bone. Crushed bone samples were irradiated using photon beams with effective energies in the range from 0.06 to 6 MeV, and electron beams with mean energies in the range from 2 to 10 MeV. The photon and electron data were normalized to a dose to bone of 50 Gy and the results are reported as response relative to the ESR signal for photon irradiation at 1.25 MeV ("6"0Co). The photon irradiation results show that the ESR response is greatest at low energies with a relative value of 1.2 at 0.06 MeV. The relative response decreases, as the energy increases, to approximately 0.85 in the region of 2 to 3 MeV. These variations in the relative ESR responses are significantly less than the ...

International Nuclear Information System (INIS)

The giant resonance regions of "9"0Zr, "1"1"6Sn, "1"4"4Sm and "2"0"8Pb were investigated using 240 MeV #alpha# particle scattering at small angles including 0 deg. E1 strengths corresponding to 91#+-#11%, 89#+-#10%, 105#+-#12% and 95#+-#13% of the isoscalar E1 energy-weighted sum rule were identified between 18#<=#E_x#<=#31 MeV, 16#<=#E_x#<=#30 MeV, 15#<=#E_x#<=#27 MeV and 15#<=#E_x#<=#25 MeV with centroid energies of 24.8#+-#0.4 MeV, 22.5#+-#0.3 MeV, 21.6#+-#0.3 MeV and 19.3#+-#0.3 MeV and rms widths of 3.2#+-#0.2 MeV, 3.5#+-#0.2 MeV, 3.2#+-#0.2 MeV and 2.5#+-#0.2 MeV for "9"0Zr, "1"1"6Sn, "1"4"4Sm and "2"0"8Pb, respectively. Parameters obtained for ...

International Nuclear Information System (INIS)

We measured neutron time-of-flight spectra from 90 MeV protons and 140 MeV alpha particles bombarding thin targets of Al, Ni, Zr, and Bi at laboratory angles between 20_0 and 135_0. The low-energy (5 to 45 MeV) portions of the spectra were measured with 5 cm diameter by 5 cm deep NE-213 counters at 1 m flight paths with n-#betta# pulse-shape discrimination. The high-energy (35 to 150 MeV) portions of the spectra were measured with 12.7 cm diameter by 10.2 cm deep NE-102 counters at flight paths of 2.0 to 5.0 m. The proton-induced measured neutron spectra reveal three distinct energy regions: a low-energy evaporation region, a high-energy region dominated by the quasifree scattering process, and an intermediate-energy region dominated by multistep, preequilibrium processes. In the ...

Energy Technology Data Exchange (ETDEWEB)

Depth dose distributions for protons in the energy range from 2 to 600 MeV have been calculated by Monte Carlo and analytical methods. The dependence on energy of Maximum Dose Equivalent (MDE), quality factor and isotropic factor recommended for practical use are presented. The problems connected with regulation of maximum permissible proton fluxes are discussed. (author).

International Nuclear Information System (INIS)

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

International Nuclear Information System (INIS)

Cell death after irradiation occurs by apoptosis in certain cell populations in tissues. The phenomenon also occurs after high linear energy transfer (LET) irradiation, and the relative biological effectiveness (RBE) is 3 to 4 (with respect to low-LET radiation and apoptosis in intestinal crypts) for neutrons with energies of 14 MeV and up to 600 MeV. It is thought that p53 plays a role in the phenomenon, as radiation-induced apoptosis is not observed in p53-null animals. (orig.).

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A detector has been developed and used to measure dose distributions versus linear energy transfer to thin gas targets in spherical geometry from fast neutron irradiation of tissue-equivalent plastic and carbon. The detector is a hemispherical proportional counter with a Cs(T1) scintillator at the center of the hemisphere. The coincidence of the proportional counter signals constrain the measurements to charged particles traversing the radius of the hemisphere. The charged particle energy deposition distributions are directly measured for a known pathlength. The A-150 kerma factor was measured at a neutron energy of 14.8 MeV and is in agreement with tabulated values. The carbon kerma factor measurements are less than the tabulated value at 14.8 MeV. The alpha-particle production in carbon was measured for neutron energies from 14.1 to 14.8 ...

International Nuclear Information System (INIS)

This study investigated dose to bone tissue in electron beam therapy. Measurements were made using films and thermoluminescent dosimeters in a polystyrene phantom containing bone inhomogeneity for 15-MeV, 12-MeV, and 9-MeV electron beams. An increase in dose of approximately 18%, 12%, and 11%, for the three electron energies respectively, relative to the dose in polystyrene, was found for bone material having an electron density (relative to water) of 1.73. Measurements were also made using films for 15- and 9-Mev electrons in a phantom with a mandibular bone and teeth. A dose enhancement in bone of approximately 10% and 7%, respectively, for the two energies was found in the phantom where the electron density of bone was about 1.60. These results suggest that injury to bone is possible in those clinical situations where high doses of electrons are used for ...

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The production of the {lambda}- and {sigma}{sup 0}-hyperons has been measured via the pp{yields}pK{sup +}{lambda}/{sigma}{sup 0} reaction at the internal COSY-11 facility in the excess energy range between 14 and 60 MeV. The transition of the {lambda}/{sigma}{sup 0} cross-section ratio from about 28 at Q{<=}13 MeV to the high-energy level of about 2.5 is covered by the data showing a strong decrease of the ratio between 10 and 20 MeV excess energy. Effects from the final-state interactions in the p-{sigma}{sup 0} channel seem to be much smaller than in the p-{lambda} channel. Estimates of the effective range parameters are given for the N{lambda} and the N{sigma} systems. (orig.)

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A comprehensive Scanning Tunneling Microscopy (STM) study of submonolayer nucleation and growth of 2D islands in Ag/Ag(100) homoepitaxy for temperature between 295K and 370K is presented. The initial stages of multilayer kinetic roughening is also studied. Analysis of an appropriate model for metal (100) homoepitaxy, produces estimates of 350 meV for the terrace diffusion barrier, 400 meV for the adatom bond energy, and 25 meV for the additional Ehrlich-Schwoebel step-edge barrier.

International Nuclear Information System (INIS)

The (p,n) cross section on "8"8Sr was measured for proton energies between 5.75 and 11 MeV. Overall resolution was sufficient to separate the "8"8Y ground state (J/sup #pi#/ = 4"-), the first excited state (J/sup #pi#/ = 5"-) at 0.232 MeV, and the second excited state (J/sup #pi#/ = 1"+) at 0.393 MeV. A Legendre polynomial fit was made to the angular distributions and the resulting integrated cross sections are shown. 1 figure.

Energy Technology Data Exchange (ETDEWEB)

In a (p,p') study of /sup 88/Sr at Esub(p) = 201 MeV both a large resonance centered at 9.4 MeV excitation energy and the known 1/sup +/ state at 3.486 MeV are excited. Several discrete states are observed in the resonance. The cross section of the whole resonance is 27% of a simple particle-hole prediction. The strength of the low-lying 1/sup +/ state is only about 15% of that calculated from a wave function including core-polarization contributions, whereas (e,e') scattering finds about 50%.

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For the purpose of optimizing the process of co-implantation of MeV Si ions to reduce boron transient enhanced diffusion and boron-enhanced diffusion in Si, multiple MeV implantations and annealing at different temperatures have been performed. A slight improvement on the suppression of B diffusion is observed by adding a low temperature annealing step after the MeV implantation. No differences in B diffusion are observed when the Si doses are increased from 1 x 10{sup 15} to 1 x 10{sup 16} cm{sup -2}. This dose independent behavior is speculated to be a quasi-steady state of vacancy cluster evaporation.

International Nuclear Information System (INIS)

We measured differential cross sections and vector analyzing powers for the "4"8Ca(d,n)"4"9Sc reaction at 79 MeV. An overall energy resolution of about 325 keV was achieved, and data were extracted for states up to 3.4 MeV of excitation. Both distorted-wave Born approximation and Johnson-Soper adiabatic approximation calculations were performed; in general, the Johnson-Soper adiabatic approximation calculations provide a better description of the data, and yield reasonable spectroscopic factors.

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Differential elastic and inelastic neutron-scattering cross sections of elemental iron are measured from 4.5 to 10 MeV in increments of {approx}0.5 MeV. The measurements are made at >or{approx}40 scattering angles distributed between {approx}17 and 160 , with emphasis on elastic scattering and inelastic scattering due to the excitation of the yrast 2{sup +} state. The measured data is combined with earlier lower-energy results from this laboratory, with recent high-precision {approx}9.5-15 MeV results from the Physikalisch. Technische Bundesanstalt and with selected values from the literature to provide a detailed neutron-scattering data base extending from {approx}1.5 to 26 MeV. This data is interpreted in the context of spherical-optical and coupled-channels (vibrational and rotational) models, and the physical implications are discussed. Deformation, coupling, asymmetry and ...

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Nuclear reaction cross-sections for stable strontium and cesium isotopes, which were calculated by different approaches, are compared to available experimental data. Neutron and proton induced reaction cross-sections for the long-lived radionuclides [sup 90]Sr and [sup 137]Cs have been calculated in the energy range from 1 MeV to 10 GeV. Recommendations concerning cross-section calculations for strontium and cesium isotopes at intermediate and high energies are given. (orig.)

International Nuclear Information System (INIS)

The method of treatment of uteral cancer by the brake irradiation of 25 MeV betatrone using original devices which promote forming therapeutic figured bunches is presented. The binding of the protective blocks with a special adjusting frame within the aperture of the diaphragm provided for low relative entering dose which is the advantage of high energy irradiation bunch. The use of the forming devices makes it possible to practice individual treatment and decrease the levels of irradiation doses for intact organs and tissues.

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.

CERN Document Server

PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antinuclei with a precision of the order of $10^{-8}$). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, $15^{th}$ 2006 in a $350\\times 600 km$ orbit with an inclination of 70 degrees. In this work we describe the scientific objectives and the performance of PAMELA in its first two years of operation. Data on protons of trapped, secondary and galactic nature - as well as measurements of the December $13^{th}$ 2006 Solar Particle Event - are also provided.

International Nuclear Information System (INIS)

Elastic scattering of 22 MeV alpha particles by "2"3Na, sup(24-25-26)Mg, "2"7Al and "2"8Si has been measured between 24"0 and 174"0 lab. Partial angular distributions, from 120"0 to 174"0, were also measured at incident energies of 18.4 and 20.7 MeV for "2"4Mg, and 18.9 and 20.5 MeV for "2"8Si. The most striking feature of the data is the large angle behaviour: spin-zero nuclei display more pronounced backward oscillations and the cross section rises more steeply towards 180"0 for 4n nuclei than for the others. (Z.M.).

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We have developed an energy-extension method of a Bragg curve counter (BCC) at the high-energy end for the measurements of double-differential cross-sections (DDXs) of fragment productions induced by tens of MeV protons. In this method, we estimate the incident energies of the fragments penetrating a BCC on the basis of the energy loss and atomic number (Z). We applied this method to the DDX measurements of the {sup nat}C(p, Li) and {sup nat}C(p, Be) reactions induced by 70 MeV protons. The validity of this method has been confirmed by comparing the DDXs of beryllium with theoretical predictions of the PHITS code and the two-body kinematics. This method improves the energy acceptance of the BCC for light fragments twice as wide as that of a conventional method without remodeling of the BCC and any loss of the original advantages.

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We have measured the K-shell ionization probability Psub(K) across the isobaric analog resonances in the elastic channel of the reactions /sup 88/Sr(p, p/sub 0/)/sup 88/Sr at 5.06 MeV and /sup 86/Sr(p, p/sub 0/)/sup 86/Sr at 6.02 MeV. The dependence of Psub(K) on the beam energy for two scattering angles 90/sup 0/ and 155/sup 0/ is analysed in the framework of the theory developed by Anholt et al. taking into account the effect of compound-nucleus scattering. A compound elastic cross section (dsigma/d..cap omega..)sub(CE)=40+-10 mb/se at the peak of the resonance is deduced in the reaction /sup 88/Sr+p at 5.06 MeV, while the experimental results agree with a negligible value of (dsigma/d..cap omega..)sub(CE) for the resonance in /sup 86/Sr+p at 6.02 MeV.

International Nuclear Information System (INIS)

Neutron-hole states in /sup 87/Sr were studied by means of the /sup 88/Sr("3He,#alpha#)/sup 87/Sr reaction at 36 MeV. Angular distribution measurements were carried out from 3"0 to 41"0 (lab) and analyzed with the zero-range distorted-wave Born approximation method. Spectroscopic factors have been determined for about 50 discrete levels in /sup 87/Sr located below 6 MeV excitation energy and for the three lowest isobaric analog states 2p(3/2, 1f(5/2, and 2p(1/2 observed around 11 MeV. Many l = 1 and l = 3 discrete levels are observed in the 3--6 MeV excitation energy range. In addition, a large part of the 1f-2p strength is found to lie in the higher-lying continuum up to 13 MeV (about 10% and 40% for the l = 1 and 3 contributions, respectively). The distribution of the 1f-2p neutron-hole strength is compared to previous data on neighboring ...

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The giant resonance region in several nuclei in A {>=} 90 have been re-measured using 240 MeV {alpha} particle scattering with a detector provides that both horizontal and vertical angles. Slice analyses with multipole fits were performed and strength due to both low and high energy components of the isoscalar giant dipole resonance (ISGDR) was identified. E1 strengths for the high energy component corresponding to 70{+-}15%,68{+-}15% and 67{+-}14% of the isoscalar E1 energy-weighted sum rule were identified, with centroid energies of 26.3{+-}0.6 MeV, 24.7{+-}0.6 MeV and 21.7{+-}0.6 MeV for {sup 90}Zr, {sup 144}Sm and {sup 208}Pb, respectively. The centroid of the high energy component of the strength distribution is in closer agreement with the microscopic prediction generated using ...

CERN Document Server

Evaluation of nuclear data has been performed for sup 2 sup 3 sup 7 Np, sup 2 sup 4 sup 1 Am, sup 2 sup 4 sup 2 sup g Am and sup 2 sup 4 sup 2 sup m Am. Neutron data were obtained at energies from 20 to 250 MeV and combined with JENDL-3.3 data at 20 MeV. Evaluation of the proton data has been done from 1 to 250 MeV. The coupled channel optical model was used to obtain angular distributions for elastic and inelastic scattering and transmission coefficients. Pre-equilibrium exciton model and Hauser-Feshbach statistical model were used to describe neutron and charged particles emission from excited nuclei. These evaluation is the first work for producing full sets of evaluated file up to 250 MeV for sup 2 sup 3 sup 7 Np and Americium isotopes.

International Nuclear Information System (INIS)

1982. p. 4.3-4.6. Israel Eisen, Y. Engler, G. Ovadia, E. Shamai, Y. Israel

CERN Document Server

The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray antiproton flux and the antiproton-to-proton flux ratio which extends previously published measurements down to 60 MeV and up to 180 GeV in kinetic energy. During 850 days of data acquisition approximately 1500 antiprotons were observed. The measurements are consistent with purely secondary production of antiprotons in the galaxy. More precise secondary production models are required for a complete interpretation of the results.

Energy Technology Data Exchange (ETDEWEB)

We have measured the K-shell ionization probability across the 6.06-MeV resonance in /sup 88/Sr(p,p/sub 0/) where the resonance width is large compared to the energy transferred to the electron. The results are found to agree quantitatively with the theory developed by Blair and Anholt. The effect of the time delay on the ionization probability, introduced by the nuclear scattering at the resonance energy, is discussed.

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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.)

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The differential cross sections for neutron emission in the reactions {sup 115}In(p,xn), {sup 115}In(d,xn), and {sup 113}Cd({alpha},xn) are measured and analyzed for proton energies 11.2 and 22.2 MeV, deuteron energy 22.3 MeV, and {alpha}-particle energies 26.8 and 45.2 MeV, respectively. The parameters of the nuclear-level density in the Fermi-gas model with negative energy shift are determined for the {sup 113}Sn, {sup 114}Sn, {sup 115}Sn, and {sup 116}Sn nuclei over a wide range of excitation energies. Analysis is performed in a statistical model that uses the Hauser-Feshbach mathematical formalism to describe multistage processes. It is shown that, as excitation energy increases, the parameter of the level density for these nuclei first decreases (this behavior is consistent with the predictions ...

International Nuclear Information System (INIS)

The experiment on the determination of the tensor polarization of the residual nucleus is described for the reaction "6Li (#alpha#, #alpha#') "6Li. It is based on the unique connection of polarization tensors t_l_m of the residual nucleus for the reaction (#alpha#, #alpha#') and the angular correlation function W (#omega#_1, #omega#_2) for #alpha#'-particle and decay product of this nucleus, where #omega#_1, #omega#_2 are motion directions of #alpha#'-particle and decay product. The angular correlations of #alpha#'-particle and deuteron are measured for the "6Li (#alpha#, #alpha#', d)"4He reaction on the 27.2 MeV #alpha#-particle beam. The recording system consists of six silicon detectors and provides the energy resolution about 0.8 MeV and the angular resolution #+-# 3 deg. The polarization tensors of the residual nucleus "6Li (2.185 MeV, 3"+) are determined as the result of measuring the angular ...

International Nuclear Information System (INIS)

Ksub(#beta#)/Ksub(#alpha#) X-ray intensity ratios have been measured for various elements between Z = 29 and Z = 79 for incident proton energies of 23.6, 32.1 and 43.6 MeV. The results yield no evidence for a variation in ratio with particle energy. (orig.).

International Nuclear Information System (INIS)

By using Bragg curve spectroscopy, one can measure atomic number and energy of high energy heavy ions stopping in a gas-filled ionization chamber with longitudinal electric field. In this paper, we report on the results obtained with an isobutane filled detector. An energy resolution of 0.8% fwhm and a Z resolution of 2.7% fwhm were achieved for elastically scattered 300 MeV "4"0Ar ions. We study the Bragg peak amplitude dependence on the energy of the incoming ions, a dependence presumably due to the Frisch grid screening inefficiency. The corrected Bragg peak spectrum of inelastically scattered 300 MeV "4"0Ar ions exhibits a satisfactory Z separation around Z = 18. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Neutron time-of flight spectra were measured from 90 MeV protons and 140 MeV alpha-particle bombardment of Al, Ni, Zr, and Bi at laboratory angles between 20/sup 0/ and 130/sup 0/. The proton induced neutron spectra reveal three distinct energy regions; a low energy evaporation region, a high-energy region dominated by quasi-free scattering processes and an intermediate-energy region dominated by multi-step, pre-equilibrium processes. In the latter two regions, the spectra show strong angular dependence. The alpha-induced neutron spectra show these same distinct energy regions plus an exponential fall-off above the beam energy per nucleon. The high-energy portions of the forward-angle neutron and proton cross sections are in ratios consistent with the assumption that single nucleon-nucleon scattering ...

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TiH{sub 2} and TiD{sub 2} thick targets were bombarded with 100 to 200 keV protons. Evidence for nuclear reactions was obtained by means of a surface barrier particle detector. Proton irradiation of TiD{sub 2} produced the following observations: {alpha} particle emission identified as (p, {alpha}) reactions from {sup 11}B and {sup 7}Li impurities in the target at ppm concentrations; and {approx}3 MeV proton and {approx}1 MeV triton emission from secondary D-D reactions caused by elastic scattering of the primary proton with a target deuteron. A 3.9 MeV {alpha} particle peak measured by others was not observed. (author)

International Nuclear Information System (INIS)

Using U-120 cyclotron in the course of correlation experiment one studied mechanisms of excitation and decay of "1"2C nucleus states resulting from irradiation of deuterium-polyethylene target by 27.2 MeV energy #alpha#-particle beam via recording of #alpha#-#alpha#-coincidence simultaneously with investigations of #alpha# + d-interactions. Production of "1"2C excited states decaying with the escape of #alpha#-particle and "8Be nucleus in the ground and the excited states is the basic mechanism of the studied #alpha# + "1"2C interaction

International Nuclear Information System (INIS)

The lifetime of the circulating electron beam in the Naval Research Laboratory modified betatron has been increased by more than 2 orders of magnitude with the addition of strong focusing windings to the device. The injected beam consistently spirals from the injector to the minor axis and is trapped. The #approx#0.5-kA trapped electron ring has been accelerated above 10 MeV from the injection energy of 0.5 to 0.6 MeV. The beam acceleration has been confirmed not only by the x-ray attenuation technique but also with the detection of photoneutrons.

International Nuclear Information System (INIS)

The charge distribution in the alpha particle induced fission of "2"0"9Bi has been studied at alpha particle energy of 55.7 MeV and 58.6 MeV. The fractional cumulative yields of "9"7Zr, "9"9Mo, "1"0"1Mo and "1"1"2Pd have been determined using gamma ray spectrometry. The charge distribution have been found to be broad. (author). 4 refs., 1 ta b.

Energy Technology Data Exchange (ETDEWEB)

The interaction between a lower hybrid wave and a fusion alpha particle displaces the alpha particle simultaneously in space and energy. This results in coupled diffusion. Diffusion of alphas down the density gradient could lead to their transferring energy to the wave. This could, in turn, put energy into current drive. Here we calculate numerical solutions for the alpha energy transfer and study a range of conditions that are favourable for wave amplification from alpha energy. We find that it is possible for fusion alpha particles to transfer a large fraction of their energy to the lower hybrid wave. The numerical calculation shows that the net energy transfer is not sensitive to the value of the diffusion coefficient over a wide range of practical values. An extension of this idea, the use of a lossy boundary to enhance the ...

Energy Technology Data Exchange (ETDEWEB)

The interaction between a lower hybrid wave and a fusion alpha particle displaces the alpha particle simultaneously in space and energy. This results in coupled diffusion. Diffusion of alphas down the density gradient could lead to their transferring energy to the wave. This could, in turn, put energy into current drive. An initial analytic study was done by Fisch and Rax. Here the authors calculate numerical solutions for the alpha energy transfer and study a range of conditions that are favorable for wave amplification from alpha energy. They find that it is possible for fusion alpha particles to transfer a large fraction of their energy to the lower hybrid wave. The numerical calculation shows that the net energy transfer is not sensitive to the value of the diffusion coefficient over a wide range of practical values. An extension of this ...

International Nuclear Information System (INIS)

Elastic scattering of 27.2 MeV #alpha# particles on "4"0Ca has been investigated. Differential cross sections have been measured in the angular range from 10 deg to 175 deg in the lab. system. The theoretical analysis has proceeded from the proposition that the results of a calculation based on the optical model in the range of small angles (less than 20 deg for "4"0Ca) are independent of parameters and shape of the potential employed. Elastic scattering of #alpha# particles at angles up to 50 deg has been calculated using three sets of the optical potential parameters in the energy range 23.37-28.92 MeV. In the range of small angles a rather similar behaviour of the calculated curves can be observed whereas in the range of medium and large angles these curves behave very differently. The success in the reproduction of the angular distributions for the entire energy range is indicative of the weak ...

International Nuclear Information System (INIS)

Data from Monte Carlo transport codes are used to model radiobiological effects. We previously reported the Fourier analysis of ionization data generated by simulating a 500-keV proton traversing water. Here, we extend Fourier analysis to energy transfer data of another radiation type, a 14-MeV #alpha#-particle. A radiobiological model based on this frequency-domain analysis views cell as an information processing system . It lends itself naturally to traditional engineering analyses. One engineering principle-the output response of a linear system to random signal-is applied here to explain the fact that there is measurable difference in the magnitude of the biological effectiveness when a given biological system is irradiated with two different radiation types of the same Linear Energy Transfer (LET).

International Nuclear Information System (INIS)

Measurements of alpha spectra in the (n, #alpha#) reactions induced on /sup 90,91/Zr at 14.3 and 18.15 MeV incident neutron energy are presented. A microscopic calculation of these spectra has been made using both pick-up and knock-on theories, and in both cases only one overall normalizing factor, which is the same for the two target nuclei and incident energies and all the considered transitions, appears as a free parameter in the calculation. Pick-up calculations provide a very satisfactory reproduction of the data. Knock-on calculations reproduce many qualitative features of the measured spectra, but do not allow a fully satisfactory reproduction of them. While the results obtained do not exclude knock-on contributions to these reactions, their presence is not established.

International Nuclear Information System (INIS)

An internuclear cascade-evaporation code is used to model energy deposition in thin slabs of silicon. This model shows that protons produce a significant number of events with effective Linear Energy Transfer (LET) greater than 8 MeV cm"2/mg and demonstrates that proton testing of microelectronic components can be an effective way to screen devices for low earth orbit susceptibility to heavy ions.

International Nuclear Information System (INIS)

Dissipation of energy of #beta#"--radiation in polyvinylchloride (PVC) was analyzed. Change of PVC properties at irradiation by beta beams with energy 2,32 MeV was characterized using potentials of inter- and intramolecular interactions as well as Born potential. Correlation between some micro- and macroproperties of PVC was detected and ways of their controlled correction were proposed. (authors)

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Ratio of the fissile isomers and prompt fissions yields has been measured in processes of neutron capture by /sup 241/Am and /sup 243/Am nuclei in the neutron energy interval from 0.2 up to 1.3 MeV. The present data and the previous results suggest that the fission Am isomers are spin structure isomers rather than shape isomers.

CERN Document Server

PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antimatter with a precision of the order of $10^{-8}$). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, 15 2006 in a $350\\times 600 km$ orbit with an inclination of 70 degrees. The detector is composed of a series of scintillator counters arranged at the extremities of a permanent magnet spectrometer to provide charge, Time-of-Flight and rigidity information. Lepton/hadron identification is performed by a Silicon-Tungsten calorimeter and a Neutron detector placed at the bottom of the device. An Anticounter system is ...

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A nuclear resonance fluorescence experiment on {sup 88}Sr has been performed with bremsstrahlung of 6.7 MeV endpoint energy. The {gamma}-ray linear polarisation has been measured with a EUROBALL CLUSTER detector used as a Compton polarimeter. The results indicate positive parity for the J=1 state at 4.742 MeV in {sup 88}Sr, in contrast to the previous interpretation as a 1{sup -} two-phonon (2{sup +}{sub 1} x 3{sup -}{sub 1}) state and in conflict with the predictions of the quasiparticle-phonon model. On the basis of such calculations the 1{sup +} state at 3.486 MeV may be considered as the 1{sup +}{sub 1} one-phonon state and the very strong 1{sup +}{sub 1}{yields}0{sup +}{sub 1} deexcitation as proton spin-flip 2p{sub 1/2}{yields}2p{sub 3/2} transition. (orig.)

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A technique capable of measuring the electron energy fluence spectra in a scattering medium was designed. These measurements were performed by setting a bremsstrahlung conversion target on the surface of a phantom, at an intermediate depth, and at a depth equal to electron mean range. The bremsstrahlung produced by the deceleration of electrons in the target was passed through an air channel in the phantom and passed forward by a pinhole collimator into a Na(Tl) detector. The measured pulse height data were unfolded to correct for the distortion of the spectrometer system by using the FORIST unfolding code. The unfolded bremsstrahlung spectra represent the electron energy fluence spectra convolution with the bremsstrahlung produced in the target. To generate the electron energy fluence spectra, the unfolded bremsstrahlung spectra were deconvoluted by using the MAZE2 unfolding code. CYLTRAN, a coupled electron-photon Monte ...

Energy Technology Data Exchange (ETDEWEB)

The literature of radiation damage measurements on cadmium zinc telluride (CZT), cadmium telluride (CT), and mercuric iodide (HgI{sub 2}) is reviewed and in the case of CZT supplemented by new alpha particle data. CZT strip detectors exposed to intermediate energy (1.3 MeV) proton fluences exhibit increased interstrip leakage after 10{sup 10} p/cm{sup 2} and significant bulk leakage after 10{sup 12} p/cm{sup 2}. CZT exposed to 200 MeV protons shows a two-fold loss in energy resolution after a fluence of 5 {times} 10{sup 9} p/cm{sup 2} in thick (3 mm) planar devices but little effect in 2 mm devices. No energy resolution effects were noted from moderated fission spectrum of neutrons after fluences up to 10{sup 10} n/cm{sup 2}, although activation was evident. Exposures of CZT to 5 MeV alpha particle at fluences up to 1.5 {times} 10{sup 10} {alpha}/cm{sup 2} ...

International Nuclear Information System (INIS)

Excitation functions (#alpha#,3n) and (#alpha#,4n) for "2"0"9Bi have been measured up to 60 MeV #alpha#-particle energy. The excitation functions are measured at 15#alpha#-particle energies by a stack foil technique in two steps. Excitation functions for the above two reactions have been reported for the first time in the energy range from 40 to 60 MeV. The measured experimental values are compared with the geometry-dependent hybrid (GDH) model in which the emission of particles prior to the equilibrium decay is taken into account whenever the interaction of projectile with the target nucleus is considered. It is found that the compound nucleus decay mechanism alone is unable to explain the experimental trend of our data. The initial exciton number 4 with different configurations has been tested and it is concluded that the configuration (2n + 2p + 0h) gives the best fit to the ...

International Nuclear Information System (INIS)

The influence of high energy electron (23 MeV) irradiation on the electrical characteristics of p-channel polysilicon thin film transistors (PSTFTs) was studied. The channel 220 nm thick LPCVD (low pressure chemical vapor deposition) deposited polysilicon layer was phosphorus doped by ion implantation. A 45 nm thick, thermally grown, SiO_2 layer served as gate dielectric. A self-alignment technology for boron doping of the source and drain regions was used. 200 nm thick polysilicon film was deposited as a gate electrode. The obtained p-channel PSTFTs were irradiated with different high energy electron doses. Leakage currents through the gate oxide and transfer characteristics of the transistors were measured. A software model describing the field enhancement and the non-uniform current distribution at textured polysilicon/oxide interface was developed. In order to assess the irradiation-stimulated changes of gate oxide ...

Energy Technology Data Exchange (ETDEWEB)

A Bragg curve counter equipped with an internal production target was developed for the measurements of double-differential cross-sections of fragment production induced by neutrons at energies of tens of MeV. The internal target permitted a large detection solid angle and thus the registration of processes at low production rates. In this specific geometry, the detection solid angle depends on the emission angle and the range of the particle. Therefore the energy, atomic number, and angle of trajectory of the particle have to be taken into account for the determination of the solid angle. For the selection of events with tracks confined within a defined cylindrical volume around the detector axis, a segmented anode was applied. The double-differential cross-sections for neutron-induced production of lithium, beryllium, and boron fragments from a carbon target were measured at 0 deg. for 65 MeV ...

Energy Technology Data Exchange (ETDEWEB)

The neutron-induced fission cross-section of {sup 233}U has been measured at the CERN n-TOF facility relative to the standard fission cross-section of {sup 235}U between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against {alpha} -particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the n-TOF facility result in data with uncertainties of {approx} 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the {sup 233}U (n,f) cross-section and, consequently, the design of energy systems based on the Th/U cycle. (orig.)

International Nuclear Information System (INIS)

The MCNPE-BO and MCNP4 Monte Carlo electron-photon codes were used to calculate the dose equivalent per unit fluence at various depths in tissue-equivalent slab phantoms for broad parallel beams of monoenergetic electrons with energies from 50 keV to 10 MeV. The study was carried out in the framework of the activities of a ICRP/ICRU Joint Task Group with the support of EURADOS WG4 (Numerical Dosimetry). Some preliminary results and comparisons as well as a general discussion on the performances of the codes are presented, demonstrating quite a satisfactory agreement among the results obtained using the two codes and those of other authors. (author).

Energy Technology Data Exchange (ETDEWEB)

Lifetime observations on a group of 358 rhesus monkeys indicate that life expectancy loss from exposure to protons in the energy range encountered in the Van Allen belts and solar proton events is influenced primarily by the dose rather than the energy of radiation. After 24 years, life expectancy losses from similar surface doses of low-LET (138-2300 MeV) and high-LET (32-55 MeV) protons are not significantly different, but the high-LET protons are associated with more deaths in the early years, while the low-LET protons contribute more to mortality in later years. In males, the most significant cause of life shortening is nonleukemia cancers.

Energy Technology Data Exchange (ETDEWEB)

Three electronic personal dosimeters (EPD-N) manufactured by Siemens, serial numbers 0635, 0658, and 0683, were tested at the Radiation Calibration Laboratory for an evaluation of their response to neutron, gamma and x-ray radiation. Designed to provide real-time neutron and photon dosimetry, the EPD-N is capable of estimating and displaying neutron and gamma dose components separately for a range of energies from 50 keV to 7 MeV for photon and 0.025 eV to > 10 MeV for neutron. All tests were conducted using the factory calibrations. A technical representative of the manufacturer indicated that site-specific calibrations are required as factory settings are calibrated for the lowest neutron energy limit of 0.025 eV. This raises concerns about the reliability of these devices in measuring neutrons when calibrations are made for a specific site radiological characterization then used at another ...

International Nuclear Information System (INIS)

Ionizing radiations that differ in number, size, and distribution of energy deposition events might be expected to cause different effects for the same absorbed dose. Furthermore, microdosimetry calculations suggest that large variations in biological effectiveness might be expected for internally deposited alpha-emitting radionuclides for the same absorbed dose, depending upon the specific activity and spatial distribution of the sources in tissue. The study described in this article was designed to demonstrate these phenomena in vitro. Cultured Chinese hamster ovary (CHO-K1 BH4) cells were exposed in vitro to inert, insoluble ceramic microspheres in zirconium dioxide labeled with "2"3"9Pu. The average exit energy of the 5.15 MeV alpha particle was calculated to be 4.3 MeV. Exposure times varied from four to seven hours to achieve the desired dose level.

International Nuclear Information System (INIS)

The "2"3"3U(n, f) cross-section has been measured at n_TOF in a wide energy range with a dedicated fission ionization chamber. We report here the results from 0.30 meV to 1 MeV neutron energy. The "2"3"3U(n, f) cross-section has been determined relative to a reference sample of "2"3"5U(n, f) measured simultaneously with the same detector. The very high instantaneous neutron flux and the intrinsically low background of the n TOF installation result in an accuracy around 3% in the whole energy range, while the energy resolution of the neutron beam allows for an accurate description of the fission cross-section by means of R-matrix analysis over a wide energy range. The present data provide the basis for a more precise evaluation of the "2"3"3U fission cross-section, and for improving the reliability of databases needed for the design of new ...

Energy Technology Data Exchange (ETDEWEB)

Cross sections for some electro- and photoinduced spallation reactions on {sup 27}Al and {sup 51}V are measured in the energy region 130 MeV to 580 MeV with the activation method. Comparisons are made with calculations based on the Dalitz formalism for virtual photon spectra, and Monte Carlo calculations based on a cascade evaporation model, respectively. By use of Bremsstrahlung with end-point energies from threshold to 750 MeV, the yields for photo- production of{pi}{sup -}leading to ground and isomeric states in {sup 197}Hg are measured with the activation method. The activity from the Hg-isotopes were measured after a chemical separation of Hg from the target material. The yields and isomeric ratios are compared with impulse approximation calculations. For the photoproduction of {sup 195m}Hg and {sup 192}Hg from {sup 197}Au, the yields were measured. The experimental mean cross ...

International Nuclear Information System (INIS)

A mixture of aminoacids was irradiated by a scattered proton beam, its energy varying from 4 to 6.6 MeV, by doses up to 5 x 10"1"1 proton/cm"2 for studying the potentiality of abiogenic synthesis of biologically important compounds in space. It was ascertained that increase in the radiation dose and reduction of proton energy involve increase in effectiveness both of destruction of the initial aminoacid (tryptophan, tyrosine, glycine) and synthesis of the relevant dipeptide. Essential influence of mineral substrate on abiogenic synthesis of natural nucleotides under the action of diverse energy sources was pointed out

International Nuclear Information System (INIS)

The #pi#g_9_/_2 band structure in "1"2"1Cs is obtained. The experiment was performed at the HI-13 MV tandem accelerator of China Institute of Atomic Energy. The excited states of "1"2"1Cs were populated via the reaction "1"1"2Sn("1"2C, p2n). The #gamma#-#gamma# coincidence data were taken with five BGO-AC HpGe detectors at beam energy of 60 Mev. The energy-level schemes of "1"2"1Cs is presented.

Energy Technology Data Exchange (ETDEWEB)

In an ionization chamber with the electric field parallel to the particle trajectories, the time dependence of the anode signal contains all the information about the energy and the nuclear charge of the ionizing particle. By proper pulse shaping with a long and a short time constant the total ionization charge and the ionization charge integrated around the Bragg maximum, respectively, can be obtained. The former signal is proportional to the total energy, whereas the latter allows the nuclear charge to be deduced directly. An energy resolution of 0.4% and a Z resolution ..delta..Z/Z = 1/82 was achieved for 130 MeV /sup 32/S ions and argon-methane as the stopping medium.

International Nuclear Information System (INIS)

Technique, allowing to investigate straggling zone (full braking) from high-energy charged particles in detail, is described. Experimental results on investigation of efective structure, created in polycrystalline molybdenum (99.97%) within 29 MeV alpha-particles straggling zone for fluences from 3.8x10"1"9 up to 3.7x10"2"1 #alpha#/m"2 by methods of microhardness (H_#mu#, X-ray structural analysis (#DELTA#a/a) and transparent electron microscopy (TEM), are presented. It is determined, that for doses from 3.8x10"2"0 #alpha#/m"2 and higher, at #approx#6 MeV energy, molybdenum ''softening'' is observed, H_#mu# curve within straggling zone is well described by alloyage calculated profile. #DELTA#a/a measurements within straggling zone are well described by damage profile. TEM-investigations have shown the developed defective structure even within molybdenum ''softening'' range.

International Nuclear Information System (INIS)

The /sup 40/Ca(p,n)/sup 40/Sc reaction was studied at 134 MeV. Neutron energy spectra were measured by the time-of-flight technique with resolutions of 220 keV at angles from 0"0 to 41"0 and 415 keV out to 62"0. The 2"-,3"-,4"-,5"- band of states based on the (f/sub 7/2/,d/sub 3/2//sup -1/) 1p1h structure was observed at low excitation energies, in good agreement with known analog states in /sup 40/Ca and /sup 40/K. The shapes of the cross-section and analyzing-power angular distributions are in good agreement with distorted-wave impulse-approximation calculations using simple 1p1h (Tamm-Dancoff approximation) shell-model wave functions. A relatively strong transition to a state at E/sub x/ = 2.3 MeV with L = 3 is identified tentatively as a 4"- state with the predominant 1p1h structure (1f/sub 7/2/,2s/sub 1/2//sup -1/).

International Nuclear Information System (INIS)

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

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In the case of total skin electron therapy without the beam guide, the electron beam is scattered just outside the gantry exit, dose uniformity in the field is broken, and dose is spread outside the light field. The aims of this study were to measure the mean energy of the off-axis incident electron beam without the beam guide and to establish a reference for the clinical situation. For the measurement, a 4 MeV electron beam was selected among several energies from the linear accelerator. A scintillating fiber beam energy monitor measured the mean energy of the incident electron beam. This energy monitor is a small, light-weight piece of equipment composed of a wedge absorber, scintillation fiber, and photodiode. We found the relationship between electron energy and the indicated value of the energy monitor by means of ...

Energy Technology Data Exchange (ETDEWEB)

We have developed a Bragg curve counter (BCC) equipped with an active cathode to extend the energy acceptance to lower energies than for a conventional BCC to measure differential cross-sections of fragment production reactions induced by tens of MeV protons. The signal from the active cathode providing the timing signal of fragment incidence and the time difference signal between the cathode and anode gives information on the fragment range in the BCC on the basis of electron drift time. Utilization of the range information made possible identification of fragments less than 0.5 MeV/u that is lower than the identification threshold of a conventional BCC technique. After investigations on fundamental properties of a newly constructed BCC using heavy ion beams and alpha-particles, this method was applied successfully to a fragment production measurement for 70 MeV proton-induced reactions on carbon. With ...

Science.gov (United States)

The experimental device for generation of undulator radiation in terahertz wavelength region by use of undulator with ferromagnets is created. The device is based on a beam of a microtron with the energy 7.5 MeV. The radiation wavelength is 200 mu. Registered spontaneous radiation has a power 10{sup -6} W at a current of a beam 2 mA in a pulse. With the optical resonator, in a mode, the amplification of 6% is received, that in sometimes is more than the expected value. This effect is explained as a result of partial coherence of radiation.

International Nuclear Information System (INIS)

The thermal stability of diffusion barriers is explored on the basis of Bi films at different expedients of deriving of films. The examinations were conducted on the electrostatic accelerator at KNU of name Karazin V.N. under conditions of an isothermal bakeout directly under a proton beam of 1,85 MeV energy.

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A new article identification method based on the measurement of Bragg-curve centroids using a gas-filled ionization chamber has been improved for detection of low-energy particles around 1 MeV per nucleon by introducing a nonuniform distribution of resistance on the anode electrode. Almost the same quality of Z-resolutions as in the conventional ..delta..E-E method could be obtained up to Z=19.

International Nuclear Information System (INIS)

Projectilelike fragments following the 80 MeV "1"6O+"2"7Al reaction have been detected using a Bragg-curve spectroscopy ionization chamber (BCS-IC). The atomic number is deduced from the Bragg-peak amplitude. Nitrogen isotopes are clearly resolved using either range or energy loss data. This is the first application of the BCS method for complete ion identification in a heavy-ion-induced reaction.

Science.gov (United States)

A {sup 92}Mo beam with an energy of {ital E}/{ital A}=70 MeV has been used to produce new isotopes near the proton drip line. The Michigan State University National Superconducting Cyclotron Laboratory A1200 fragment separator was used to detect the new isotopes {sup 78}Y, {sup 82}Nb, {sup 85}Mo, {sup 86}Tc, and {sup 89,90}Ru.

Energy Technology Data Exchange (ETDEWEB)

Following a recent refurbishment of the NPL Thermal Neutron Facility, the spectrum of the epithermal and fast neutron component of the beam produced by the thermal column of this facility was measured over the energy range from thermal to 20 MeV using a Bonner sphere spectrometry system. The effect of the presence of epithermal and fast neutrons on the measured response of commonly-used thermal neutron dosemeters was calculated. (author)

Energy Technology Data Exchange (ETDEWEB)

Characterization of the electron beam's properties will be a major task after the upgrade of the Los Alamos Free-Electron Laser (FEL) Facility with a photoelectric injector (PEI) and increased acceleration capability to 40 MeV. Adjustments to the previous diagnostics package that address the lower beam emittance, higher energy, and wakefield source reduction issues will be discussed. 6 refs., 8 figs., 1 tab.

Energy Technology Data Exchange (ETDEWEB)

The MiniBooNE Collaboration reports first results of a search for {upsilon}{sub e} appearance in a {upsilon}{sub {mu}} beam. With two largely independent analyses, we observe no significant excess of events above background for reconstructed neutrino energies above 475 MeV. The data are consistent with no oscillations within a two neutrino appearance-only oscillation model.

Energy Technology Data Exchange (ETDEWEB)

A concept of direct energy recovery system applying an alternating or rotating magnetic field is proposed for a negative-ion-based neutral beam injection system (NNB) to heat a plasma and/or drive a plasma current in a fusion reactor. Nearly same amounts of residual positive and negative hydrogen-isotope ion beams with beam energy of {approx}1 MeV are produced in an NNB using a gas neutralizing cell. Consequently, a recovered energy is obtained directly in the form of ac electric power, if these positive- and negative-ion beams are alternated or rotated and introduced to two or more recovery electrodes in turn by an alternating or rotating magnetic field. This concept will greatly reduce a technological difficulty in regeneration of a recovered electric energy with such a very high voltage. (author).

International Nuclear Information System (INIS)

The "2"3"3U(n,f) cross section has been measured at the white neutron source n_TOF in a wide energy range with a dedicated fission ionization chamber. We report here the results from #approx#30 meV to 1 MeV neutron energy. The "2"3"3U(n,f) cross section has been determined relative to a reference sample of "2"3"5U(n,f) measured simultaneously with the same detector. The very high instantaneous neutron flux and the intrinsically low background of the n_TOF installation result in an accuracy around 3% in the whole energy range, while the energy resolution of the neutron beam allows for an accurate description of the fission cross section by means of R-matrix analysis over a wide energy range. The results are, in general, in good agreement with the most recent high-accuracy measurement of this fission cross section, over the more limited range ...

Energy Technology Data Exchange (ETDEWEB)

An opportunity to study the system {sup 22}Ne+{sup 208}Pb in the proximity of the Coulomb barrier with the PRISMACLARA apparatus was given by a test of the PIAVE-ALPI accelerator in mid-December 2005. The {sup 22}Ne projectiles, having the kinetic energy of 131 MeV, collided with a {sup 208}Pb target 300 {mu}g/cm{sup 2} thick. (The beam was run for {approx}20 hours with a current of {approx}6 particle-nA). The reaction products, mainly originated by scattering or transfer processes, were detected by the PRISMA spectrometer (positioned in the proximity of the grazing angle, {approx}70 degrees), coupled to the CLARA array of germanium detectors.

Energy Technology Data Exchange (ETDEWEB)

A new method of determining the nuclear level density is presented. This method is based on the statistical analysis of the partial width fluctuations appearing in an excitation function of the radiative proton capture. The method was applied in the case of the /sup 88/Sr(p,..gamma..sub(..omega..))/sup 89/Y and /sup 89/Y(p,..gamma..sub(..omega..))/sup 90/Zr reactions. The density of levels with spin I/sup -/ in /sup 90/Zr and the densities of levels with spins 1/2/sup +/ and 3/2/sup +/ in /sup 89/Y at excitation energies from 10.9 to 11.6 MeV and from 9.3 to 10.8 MeV respectively, were determined with an uncertainty of about 35%.

International Nuclear Information System (INIS)

K-shell x-ray production cross sections and K#beta#/K#alpha# ratios have been measured for thin targets of Ti, V, Cr, Fe, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, and Y for 0.5- to 2.5-MeV alpha particles. The experimental values are compared to the nonrelativistic plane-wave Born approximation (PWBA), the binary-encounter approximation, and the PWBA with binding energy and Coulomb deflection corrections. The PWBA with corrections provides the best agreement with the experimental cross sections.

International Nuclear Information System (INIS)

Shadow effect was used for investigating damage of uranium dioxide monocrystal. The dependence of shadow minimum parameters on fluence of "2"2Ne ions with 172 MeV energy was followed when detecting fission fragments. Ion dose responsible for sufficient microdamage of lattice structure, included into the classification of heavy ion damage effect on monocrystals was determined. The problem of radiation intensity effect on the character of occurred damages was studied. It was established that macroscopic sample failure, caused by generation of considerable mechanical stresses in monocrystal under beam effect could be observed along with microdamages of lattice structure at ion flux density >10"1"2 cm"-"2Xs"-"1.

International Nuclear Information System (INIS)

The "1"2C induced fission of "2"0"9Bi at particle energy of 84.2 MeV has been studied using gamma ray spectrometry. The cross sections for the production of fission products have been determined. The charge distribution has also been studied and the relative fractional cumulative yields of "9"2Y, "9"7Zr, "9"9Mo, "1"0"1Mo, "1"0"5Rh, "1"1"2Pd and "1"1"7"mCd determined. The yield distribution of fission products has been found to be broad (FWHM #approx =# 18) with a peak near mass #approx =# 105. (author). 7 refs., 2 tabs.

International Nuclear Information System (INIS)

The alpha particle induced fission of "2"0"9Bi has been investigated for E_#alpha# = 55.7 and 58.6 MeV using gamma ray spectrometry. The cross sections for the production of fission products have been determined. The mass distributions have been found to be broad with a peak near mass 104. The charge distribution has been studied at the same particle energies. The fractional cumulative yields of "9"7Zr, "9"9Mo, "1"0"1Mo, "1"1"2Pd and "1"1"7"mCd have been determined using gamma ray spectrometry. The width of charge distribution is broad. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Both travelers were members of a nine-person US delegation that participated in an international workshop on accelerator-based 14 MeV neutron sources for fusion materials research hosted by the University of Tokyo. Presentations made at the workshop reviewed the technology developed by the FMIT Project, advances in accelerator technology, and proposed concepts for neutron sources. One traveler then participated in the initial meeting of the IEA Working Group on High Energy, High Flux Neutron Sources in which efforts were begun to evaluate and compare proposed neutron sources; the Fourth FFTF/MOTA Experimenters' Workshop which covered planning and coordination of the US-Japan collaboration using the FFTF reactor to irradiate fusion reactor materials; and held discussions with several JAERI personnel on the US-Japan collaboration on fusion reactor materials.

International Nuclear Information System (INIS)

As part of a general study of personnel neutron dosimetry systems, three British and two German TL albedo dosimeters were compared. They range from simple albedo devices to multi-element devices which detect combinations of incident and albedo neutrons. They were exposed to beams of mono-energetic neutrons, a thermal neutron column and a "2"5"2Cf source. The variation in response with neutron energy above 0.1 MeV was similar for all dosimeters. The resuls show that in general multi-component dosimeters fo not provide enough information to deduce the effective energy of incident neutrons. The choice of single or multi-element dosimeters for particular types of environment is discussed. The Harvey dosimeter has the most acceptable thermal neutron response of the simpler devices. For neutron energies below 0.5 MeV its response varies roughly as the cosine of the angle of incidence but ...

Energy Technology Data Exchange (ETDEWEB)

A technique has been developed for high resolution alpha particle spectroscopy from track length determination in CR-39 plastic. On individual tracks an energy resolution deltaE close to the range straggling limit is obtainable. For 6 MeV alpha-particle deltaE is proportional 35 keV on individual particles and for groups of particles deltaE proportional 20 keV can be achieved using certain data selection criteria. At 100 keV on individual particles deltaE is proportional 20 keV. The analysis requires 1) a knowledge of the track-etch rate (Vsub(T))-range relationship and 2) a theoretical understanding of alpha-particle track structure in CR-39 as a function of particle energy, dip angle and degree of etching. The structure of alpha-particle etched tracks in CR-39 is described and two methods of analysis discussed. Examples are given of the resolution attainable on tracks of alpha-particles as natural decay ...

Energy Technology Data Exchange (ETDEWEB)

An add-on multileaf collimator for electrons (eMLC) has been developed that provides computer-controlled beam collimation and isocentric dose delivery. The design parameters result from the design study by Gauer et al (2006 Phys. Med. Biol. 51 5987-6003) and were configured such that a compact and light-weight eMLC with motorized leaves can be industrially manufactured and stably mounted on a conventional linear accelerator. In the present study, the efficiency of an initial computer-controlled prototype was examined according to the design goals and the performance of energy- and intensity-modulated treatment techniques. This study concentrates on the attachment and gantry stability as well as the dosimetric characteristics of central-axis and off-axis dose, field size dependence, collimator scatter, field abutment, radiation leakage and the setting of the accelerator jaws. To provide isocentric irradiation, the eMLC can be placed either 16 or 28 cm above the ...

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)

Energy Technology Data Exchange (ETDEWEB)

The nuclear data activity at AERE, Savar is briefly presented in this paper. Major thrust is on the customization of cross section libraries for general purpose reactor and shielding calculations. The processing codes that are available are NJOY91.91, some AMPX-Modules and the modules in SCALE-PC. Recent measurements on cross section data over the energy range 13-15 MeV at the Institute of Nuclear science and Technology have been reviewed. Measurements and calculations are based on the determination of excitation functions of neutron induced reactions on the elements and isotopes of FRT-relevant structural materials. (author).

International Nuclear Information System (INIS)

Based on the single-particle levels given by Nilsson, the intrinsic and effective (with collective effects) level density parameters as a function of the excitation energy for the "1"8"6Os, "1'8"7Ir, "1"8"9Os and "1"9"3Au deformation nuclei have been calculated in the range of the excitation energy up to 150 MeV. The calculated fission probabilities P_f (U) are consistent satisfactorily with the experimental data when a nonadiabatic estimation of the collective effects was used to calculated the nuclear level density parameters.

International Nuclear Information System (INIS)

Bases of the algorithm for assessing the reinforcement status in reinforced concrete products by gamma-absorption method are presented. Analytical equations are obtained for estimation of error of the parameter characterizing the degree of reinforcement destruction. It is recommended to use high-energy Bremsstrahlung sources-betatrons of 4-10 MeV maximum energy for testing products of 500-600 mm thick. Linear radiation attenuation factor (LAF) of concrete in estimated equation is replaced by effective LAF of concrete, and LAF of reinforcement and corrosion materials - by differential LAF. Corresponding LAF of nonevident form in the algorithm is assessed by the results of processing of direct-shadow radiographs of defectometers

International Nuclear Information System (INIS)

Nucleosynthesis and energy production in stellar environments depend critically on nuclear reaction cross sections. Reactions induced by alpha particles are important in the helium burning stage of stars, novae, and supernovae events. They involve light to medium weight nuclei up to about Z=32, and center-of-mass energies up to about 20 MeV. We are working on a project to compile and evaluate cross section data for alpha-induced reactions. These data will eventually be used to derive #alpha#-nucleus potential parameters. (author)

Energy Technology Data Exchange (ETDEWEB)

The Fermilab Linac Upgrade is planned to increase the energy of the H- linac from 200 to 400 MeV. This is intended to reduce the incoherent space-charge tuneshift at injection into the 8 GeV Booster which can limit either the brightness or the total intensity of the beam. The Linac Upgrade will be achieved by replacing the last four 201.25 MHz drift-tube tanks which accelerate the beam from 116 to 200 MeV, with seven 805 MHz side-coupled cavity modules operating at an average axial field of abut 7.5 MV/m. This will allow acceleration to 400 MeV in the existing Linac enclosure. Each accelerator module will be driven with a klystron-based rf power supply. A prototype rf modulator has been built and tested at Fermilab, and a prototype 12 MW klystron is being fabricated by Litton Electron Devices. Fabrication of production accelerator modules is in progress. 8 figs., 4 tabs.

Energy Technology Data Exchange (ETDEWEB)

Portal localization images for high-energy electron beam therapy are necessary to confirm the treatment field by comparing them with a simulation image obtained before treatment or portal verification images after treatment. In this study, portal localization images were acquired using the computed radiography (CR) system and bremsstrahlung X-rays generated in the electron beam irradiations. All images obtained with phantom and the irradiations of in the electron energy of 8, 10, 12 and 15 MeV were feasible for clinical use. The CR system used in this study included general diagnostic imaging cassette and storage phosphor plate, but none of other special devices. The system can usually supply portal localization images, which maintains the quality assurance of high-energy electron beam therapy. (author)

Energy Technology Data Exchange (ETDEWEB)

The primary E1, M1 and E2 ..gamma..-radiation in /sup 87,88,89/Sr observed after thermal neutron capture was compared with the predictions of single particle and giant resonance models. The nuclei feature a wide range of neutron binding energies between 6.3 and 11.1 MeV, which makes a 5.5 MeV spectrum of primary transition energies available for investigation. The (n, ..gamma..) reaction was used to estimate the parameters of the spin-flip M1 giant resonance in strontium. The total energy weighted M1 strength of this resonance exceeds the results of shell model and random phase approximation calculations for /sup 90/Zr by a factor of 3-4. The E1 strengths were found to agree with the established giant dipole resonance model. The few data on primary E2 transitions do not allow to differentiate between the giant quadrupole resonance and the single particle models.

International Nuclear Information System (INIS)

The high-spin structure of the Z=77 nucleus "1"8"7Ir has been studied using the fusion-evaporation reaction "1"8"6W("7Li6n) at a beam energy of 59 MeV. The excitation scheme of this nucleus has been extended by more than 110 new states, including extensions of all previously established rotational bands. The band crossing region of the h_9_/_2 negative-parity yrast band has been revised and new intrinsic high-K states have been identified. In particular, a 29/2"- isomeric state [T_1_/_2=1.8(5)#mu#s] at an excitation energy of 2487 keV has been observed for the first time, and on top of it, a rich level scheme reaching up to spin (59/2"-) and excitation energies around 7 MeV has been established.

International Nuclear Information System (INIS)

Elise is a heavy ion induction linear accelerator that will demonstrate beam manipulations required in a driver for inertial fusion energy. With a line charge density similar to that of heavy ion drivers, Elise will accelerate a #>=# 1 gs beam pulse of K"+ ions from an initial energy of 2 MeV to a final energy #>=# 5 MeV. In the present design, the Elise electrostatic quadrupoles (ESQ) will have a 2.33 cm radius aperture operating at #+-#59 kV. The half-lattice periods range from 21 cm to 31 cm. The entire machine will be approximately 30 m long, half of that is the induction accelerator and the remaining half is the injector (including the Marx generator) and the matching section. Elise will be built in a way that allows future expansion into the full ILSE configuration, therefore it will have an array of four ESQ focusing channels capable of transporting up to a total of 3.2 ...

Energy Technology Data Exchange (ETDEWEB)

Technologies producing high power negative ion beams have been highly developed in these years at JAERI for use in neutral beam injectors for heating the thermonuclear fusion plasmas. At present, it is possible to produce multi-ampere H-/D- ion beams quasi-continuously at energies more than a few hundred keV with a good beam optics of beamlet divergence of a few milli-radian. Based on these technologies, two R and D projects have been initiated; one is to develop a 22A/500keV/10s D- ion source for the neutral beam injector for JT-60U, and the other is to develop a 1A/1MeV/60s H- ion source to demonstrate high current negative ion acceleration up to the energy of 1MeV, the energy required for the neutral beam injector for International Thermonuclear Experimental Reactor (ITER). (author).

Energy Technology Data Exchange (ETDEWEB)

A balloon-borne instrument has measured the cosmic-ray antiproton flux between 130 and 320 MeV and searched for antihelium between 130 and 370 MeV per nuclear. These particles were selected from the background of normal-matter cosmic rays by combining a selective trigger with a detailed spark chamber visualization of each recorded event. Antiprotons are identified by their characteristic annihilatin radiation. Residue from background processes meeting the selection criteria is small. The observed 14 antiprotons yield a measured differential flux of 1.7 +- 0.5 x 10/sup -4/ antiprotons m/sup -2/ sr/sup -1/ s/sup -1/ MeV/sup -1/ at the top of the atmosphere. The corresponding antiproton/proton ratio is 2.2 +- 0.6 x 10/sup -4/,, only slightly smaller than the ratio observed by other experiments at higher energies. Thus the antiprotons have a spectral shape similar to the protons, at least down to about 100 ...

International Nuclear Information System (INIS)

Results of an experimental study of the interaction of 140 MeV alpha particles with _9_0Zr nuclei resulting in fragmentation of the alpha particle are reported. The experimental observations of the study are analyzed and are found to show that alpha particle breakup reactions leading to at least 4-body final states, composed of two charged alpha particle fragments, contribute significantly to the singles yield of charged fragments observed at a fixed forward angle. The conclusions are based on coincidence measurements where one charged fragment is detected at a small forward angle which remains fixed, while the second charged fragment is detected at a series of coplanar secondary angles. The largest coincidence charged particle yield for the multiparticle final state events results from _9_0Zr(#alpha#,pp)X reactions, where both of the measured protons have energy distributions similar to the proton singles energy ...

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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 have been normalized to the observed flux of Berk 87 by using different input proton ...

International Nuclear Information System (INIS)

The quenched chiral logarithms are examined on a 163x28 lattice with Iwasaki gauge action and overlap fermions. The pion decay constant fpi is used to set the lattice spacing, a = 0.200(3) fm. With pion mass as low as #approx#180 MeV, we see the quenched chiral logarithms clearly in mpi2/m and fP, the pseudoscalar decay constant. The authors analyze the data to determine how low the pion mass needs to be in order for the quenched one-loop chiral perturbation theory (chiPT) to apply. With the constrained curve-fitting method, they are able to extract the quenched chiral logarithmic parameter delta together with other low-energy parameters. Only for mpi<=300 MeV do we obtain a consistent and stable fit with a constant delta which they determine to be 0.24(3)(4) (at the chiral scale Lambdachi = 0.8 GeV). By comparing to the 123x28 lattice, they estimate the finite volume effect to be about 2.7% for the smallest pion mass. ...

International Nuclear Information System (INIS)

A new formulation of meson self-energies is introduced for #sigma#,#omega#,#pi#,#rho#,#delta#, and #eta# mesons on the basis of the particle-hole-antiparticle representation. We have studied the difference between the meson self-energy (MSE) of this representation and the MSE of the traditional density-Feynman (DF) representation. It is shown that the new formulation describes exactly the physical processes such as particle-hole excitations or particle-antiparticle excitations, and that, on the other hand, the meson self-energy based on the DF representation includes unphysical components. By numerical calculations, the meson self-energies describing the particle-hole excitations are shown to be close to each other for most of the meson self-energy in low momentum (R<500 MeV) and low energy (R_0<200 MeV). This fact ...

Energy Technology Data Exchange (ETDEWEB)

Research preformed consisted of: (1) publication of an experimental paper for the n + {sup 40}Ar high resolution total cross section and submission of a theoretical paper dealing with the prediction of the average parameters deduced from the the data; (2) preliminary R-matrix analysis of the neutron total cross section data for the n + {sup 208}Pb systems, up to an energy of 1.7 MeV; (3) completed the analysis of neutron total cross section of data for n + {sup 54}Fe up to energy of 500 keV, with j{sup {pi}} values confirmed, in most cases, by differential scattering data; (4) analysis of total cross section data for the n + {sup 88}Sr system up to an energy of 175 keV; (5) development of a graphical interface for the code RFUNC, used to calculate the differential scattering cross sections, for comparison with measurements.

Energy Technology Data Exchange (ETDEWEB)

The advance in laser-plasma acceleration techniques pushes the regime of the resulting accelerated particles to higher energies and intensities. In particular the upcoming experiments with the FLAME laser at LNF will enter the GeV regime with almost 1nC of electrons. From the current status of understanding of the acceleration mechanism, relatively large angular and energy spreads are expected. There is therefore the need to develop a device capable to measure the energy of electrons over three orders of magnitude (few MeV to few GeV) under still unknown angular divergences. Within the PlasmonX experiment at LNF a spectrometer is being constructed to perform these measurements. It is made of an electro-magnet and a screen made of scintillating fibers for the measurement of the trajectories of the particles. The large range of operation, the huge number of particles and the need to focus the divergence ...

International Nuclear Information System (INIS)

The half-value thicknesses, linear and mass attenuation coefficients of biological samples such as bone, muscle, fat and water have been measured at 140, 364 and 662keV ?-ray energies by using the ATOMLABTM-930 medical spectrometer. The ?-rays were obtained from 99mTc, 131I and 137Cs ?-ray point sources. Also theoretical calculations have been performed in order to obtain the half-value thicknesses and, mass and linear attenuation coefficients at photon energies 0.001keV-20MeV for bone, muscle and water samples. The calculated value and the experimental results of this work and the other results in literature are found to be in good agreement.

CERN Document Server

Monte Carlo calculations using the codes PENELOPE and GEANT4 have been performed to characterize the dosimetric properties of monoenergetic photon point sources in water. The dose rate in water has been calculated for energies of interest in brachytherapy, ranging between 10 keV and 2 MeV. A comparison of the results obtained using the two codes with the available data calculated with other Monte Carlo codes is carried out. A chi2-like statistical test is proposed for these comparisons. PENELOPE and GEANT4 show a reasonable agreement for all energies analyzed and distances to the source larger than 1 cm. Significant differences are found at distances from the source up to 1 cm. A similar situation occurs between PENELOPE and EGS4.

Energy Technology Data Exchange (ETDEWEB)

Prompt fission neutron spectrum measurements at the University of Massachusetts Lowell 5.5 MV Van de Graaff accelerator laboratory require that the neutron detector efficiency be well known over a neutron energy range of 100 keV to 20 MeV. The efficiency of the detector, has been determined for energies greater than 5.0 MeV using the Weapons Neutron Research (WNR) white neutron source at the Los Alamos Meson Physics Facility (LAMPF) in a pulsed beam, time-of-flight (TOF) experiment. Carbon matched polyethylene and graphite scatterers were used to obtain a hydrogen spectrum. The detector efficiency was determined using the well known H(n,n) scattering cross section. Results are compared to the detector efficiency calculation program SCINFUL available from the Radiation Shielding Information Center at Oak Ridge National Laboratory.

Energy Technology Data Exchange (ETDEWEB)

Coded imaging techniques using thick, micro-Fresnel zone plates as coded apertures have been used to image x-ray emissions (2-20 keV) and 3.5 MeV Alpha particle emissions from laser driven micro-implosions. Image resolution in these experiments was 3-8 ..mu..m. Extension of this coded imaging capability to higher energy x-rays (approx. 100 keV) and more penetrating charged particles (e.g. approx. 15 MeV protons) requires the fabrication of very thick (50-200 ..mu..m), high aspect ratio (10:1), gold Fresnel zone plates with narrow linewidths (5-25 ..mu..m) for use as coded aperatures. A reactive ion etch technique in oxygen has been used to produce thick zone plate patterns in polymer films. The polymer patterns serve as electroplating molds for the subsequent fabrication of the free-standing gold zone plate structures.

Science.gov (United States)

Least-squares analyses were performed on a set of atomic masses using standard and generalized senaiempirical mass laws. Presumably because of errors in the assured form of the standand mass law, its least-squares coefficients can be determined at best to an accuracy of about 10%, and masses are predicted with an uncertainty of several Mev/c/sup 2/. The standard mass law was generalized by addition of shell effect and deformation terms. While the least-squares fitting of the generalized mass law is better than for the standard mass law, it is still not possible to predict atomic masses to an accuracy better than a few Mev/c/sup 2/. The nuclear deformations and the well depth . of the nuclear interaction obtained from the additional mass-law terms are in reasonable agreement with more accurate determinations by other methods. A similar statement applies to the nuclear radius constant as obtained from the ...

CERN Document Server

A calorimetric-time-of-flight (CTOF) technique was used for real-time, high-precision measurement of neutron spectrum at the angle of 175 degrees from the initial proton beam direction, which hits a face plane of a cylindrical iron target of 20 cm in diameter and 25 cm thick. A comparison was performed between the neutron spectra predicted by the MARS and the MCNPX code systems and measured by experiments for 0.4-, 0.6-, 0.8-, 1.0-, and 1.2-GeV protons.

International Nuclear Information System (INIS)

Compositions (oligomers with suitable properties and Al, Fe, Cu, Ta, W powders) were hardured by the flux of accelerated electrons at 10 mA beam current and 1.5 MeV energy. Dielectric and mechanical properties of metal-filled polymeric compositions as well as their radioply sicl properties in SHF-range are studied. It is shown that the produced compositions belong tot he absorbing protective materials in which the protection effect is mainly achieved through the absorption losses. 6 refs.; 3 tabs.

Energy Technology Data Exchange (ETDEWEB)

The first measurement of the pn{yields}d{omega} total cross-section has been achieved at mean excess energies Q{approx}28 and 57 MeV by using a deuterium cluster-jet target. The momentum of the fast deuteron was measured in the ANKE spectrometer at COSY-Juelich and that of the slow ''spectator'' proton (p{sub sp}) from the pd{yields}p{sub sp}d{omega} reaction in a silicon telescope placed close to the target. The cross-sections lie above those measured for pp{yields}pp{omega} but seem to be below theoretical predictions. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The ongoing upgrade of the Los Alamos Free-Electron Laser (FEL) Facility involves the addition of a photoelectric injector (PEI) and acceleration capability to about 40 MeV. The electron-beam and high-speed diagnostics provide key measurements of charge, beam position and profile, divergence emittance, energy (centroid, spread, slew, and extraction efficiency), micropulse duration, and phase stability. Preliminary results on the facility include optical transition radiation interferometer measurements of divergence (1 to 2 mrad), FEL extraction efficiency (0.6 {plus minus} 0.2%), and drive laser phase stability (< 2 ps (rms)). 10 refs.

Energy Technology Data Exchange (ETDEWEB)

The High Exposure Facility is a collimated high-level gamma irradiator that is located in the basement of the 318 building. It was custom developed by PNNL back in 1982 to meet the needs for high range radiological instrument calibrations and dosimeter irradiations. At the time no commercially available product existed that could create exposure rates up to 20,000 R/h. This document is intended to pass on the design criteria that was employed to create this unique facility, while maintaining compliance with ANSI N543-1974, "General Safety Standard for Installations Using Non-Medical X-Ray and Sealed Gamma-Ray Sources, Energies up to 10 MeV."

British Library Electronic Table of Contents (United Kingdom)

In Korea, the Proton Engineering Frontier Project (PEFP) is building a proton linear accelerator facility with energy up to 100MeV and a beam current of 20mA. In this study, a radiation field after shutdown in the accelerator facility of the PEFP was evaluated for the purpose of the radiation shielding by using MCNPX code. A facility modeling was performed for the accelerator tunnel building, accelerator chain, target rooms and beam experiment hall. And radiation source terms were evaluated in the facility. With this facility, model and radiation source terms, the concentration of 41Ar was evaluated and the cooling time satisfying regulation in Korea was calculated.

International Nuclear Information System (INIS)

The wide-angle spectra of the 134-MeV (p,n) reaction on "4"8Ca, "5"4Fe, "8"8Sr, and "2"0"8Pb are each dominated by the excitation of a single state at low excitation energy. These excitations correspond to the ''0h#omega#'' stretched states and are seen to be fragmented much less than ''1h#omega#'' stretched states in medium- and heavy-mass nuclei. The normalization factors required for comparison with distorted-wave impulse-approximation calculations are >0.50 and indicate that these are the purest particle-hole states known in these nuclei.

International Nuclear Information System (INIS)

PEFP(Proton Engineering Frontier Project) is developing beamlines for various application fields by using the high current 100MeV proton linear accelerator. Beamlines were characterized and categorized by the beam energy, average currents, and irradiation conditions. Among these beamlines the TR104 is designed for the basic science and the research of the aerospace. Before the construction and installation of beamlines, we try to practice and prepare the detail process of installation by the precedent study of TR104 beamline in KAERI site. By this work installation process was checked and confirmed for the same condition of the PEFP site

International Nuclear Information System (INIS)

We have developed a new type personal dosemeter by using a B-10 doped silicon p-n junction detector with a polyethylene radiator and a polyethylene moderator. The purpose of this study was to develop a real time neutron dosemeter with a nearly flat response in the energy range from thermal to 15 MeV and low angular dependence to the incident neutron direction. The neutron response of the dosemeter was obtained with the Monte Carlo calculation and the monoenergetic neutron experiment in a free air field and also under a condition attached on a phantom.

Energy Technology Data Exchange (ETDEWEB)

Energy and angular double differential cross-section data of fragments by tens of MeV neutron or proton are important to evaluate dosimetry and radiation effect in devices or instruments, since fragments cause a large local ionization. Up to now, experimental data of the fragment production are very scarce due to experimental difficulties of fragment detection. A bragg curve spectrometer (BCS) for fragment measurement is a gridded-ionization chamber that identify fragments on the basis of the difference of Bragg peak value. The BCS was fabricated to adopt for fragment measurement in neutron-induced reactions and tested with a charged-particle beam and then applied to a neutron field successfully. The structure of BCS is a cylindrical gridded ionization chamber, and filled with a Ar + 10% CH{sub 4} gas at a pressure of 2.7 x 10{sup 4} Pa. To confirm the performance of BCS, the following tests were performed: 1) the saturation property by using ...

Energy Technology Data Exchange (ETDEWEB)

The cross section for np{yields}d{gamma} is calculated at energies relevant to big-bang nucleosynthesis using the recently developed effective field theory that describes the two-nucleon sector. The E1 amplitude is computed up to N{sup 3}LO and depends only upon nucleon-nucleon phase shift data. In contrast, the M1 contribution is computed up to next-to-leading order, and the four-nucleon-one-magnetic-photon counterterm that enters is determined by the cross section for cold neutron capture. The uncertainty in the calculation for nucleon energies up to E{approx}1 MeV is estimated to be (less-or-similar sign)4%. (c) 1999 The American Physical Society.

International Nuclear Information System (INIS)

Stage III and stage IV recovery have been investigated resistometrically following 6.1 MeV alpha-particle irradiation at 4.2 K. The activation energy associated with stage III shows a gradual increase from 0.35 +- 0.02 eV to 0.39 +- 0.02 eV. Stage IV (155 to 180 K) is associated with an activation energy of 0.46 +- 0.03 eV. The present results are compared with those obtained after electron and neutron irradiation. The stage III recovery kinetics are interpreted in terms of the Goesele-Seeger theory for interstitial migration in highly anisotropic hexagonal metals. Stage IV is ascribed to monovacancy migration. (author).

Energy Technology Data Exchange (ETDEWEB)

Making use of a back-to-back type double fission chamber and a lead slowing-down spectrometer driven by a 46 MeV electron linear accelerator, the fission cross sections of Am-241, Am-242m and Am-243 have been measured relative to that of U-235 from 0.1 eV to 10 keV with the energy resolution of about 40 % full width at half maximum. Each of the measured result has been compared with (1) the evaluated nuclear data in ENDF/B-VI and JENDL-3.2, and (2) the existing experimental data, whose evaluated and measured data were broadened by the energy resolution function of the spectrometer.

Energy Technology Data Exchange (ETDEWEB)

A new class of low aspect ratio toroidal hybrid stellarators is found using more general plasma confinement optimization criterion than quasi-symmetrization. The plasma current profile and shape of the outer magnetic flux surface are used as control variables to achieve near constancy of the longitudinal invariant J* on internal flux surfaces (quasi-omnigeneity), in addition to a number of other desirable physics target properties. We find that a range of compact (small aspect ratio A), high {beta} (ratio of thermal energy to magnetic field energy), low plasma current devices exist which have significantly improved confinement both for thermal as well as energetic (collisionless) particle components. With reasonable increases in magnetic field and geometric size, such devices can also be scaled to confine 3.5 MeV alpha particle orbits.

Energy Technology Data Exchange (ETDEWEB)

A passive dosemeter, based on a Makrofol ED track detector covered with aluminized Mylar, enclosed in diffusion chamber, has been used for radon concentration studies. Detectors have been irradiated, using a {sup 241}Am source, at different energies and fluences in order to obtain the electrochemical etching conditions that allow the optimum registration of alpha particles having energies over 3 MeV. Thirty dosemeters have been sent to the UK National Radiation Protection Board (NRPB) Radon Environmental Chamber for calibration. The sensitivity of the dosemeter has been calculated. Several dosemeters have also been exposed in houses and dwellings in the Barcelona and Madrid areas for monitoring. Values for radon concentration in the areas under study are presented. (author).

Energy Technology Data Exchange (ETDEWEB)

Pd/n-Si and Pd/n-GaAs devices have been irradiated from high energy ({approx}100 MeV) heavy ions of Au{sup 7+} (gold) and Si{sup 7+} (silicon) to study the irradiation effects in these junction devices on semiconductor substrates. The devices have been characterized from I-V and C-V studies for electronic flow characterization. It has been found that the devices become high resistive on the irradiation and the substrates change the conductivity type from n- to p- on the irradiation of fluence of {approx}10{sup 12}-10{sup 13} ions/cm{sup 2}. The change in conductivity type has been understood as a result of creation of deep acceptors on the irradiation.

International Nuclear Information System (INIS)

We have investigated the diffusion of Sb in Si in the presence of defects injected by high-energy implantation of Si ions at room temperature. MeV ion implantation increases the concentrations of vacancies, which induce transient-enhanced diffusion of Sb deposited in Si. We observed a significant enhancement of Sb diffusion. Secondary ions mass spectroscopy has been performed on the implanted samples before and after annealing. Rutherford-backscattering spectrometry has been used to characterize the high-energy implantation damage. By fitting diffusion profiles to a linear diffusive model, information about atomic scale diffusion of Sb, i.e. the generation rate of mobile state Sb and its mean migration length were extracted.

CERN Document Server

CR-39 detectors have been exposed to a 5.9-MeV antiproton beam using the low energy antiproton ring (LEAR) facility at CERN. At this energy, tracks of antiprotons appear in a CR-39 detector after 135 min of etching in 6 M NaOH at 70C. Fluence of the antiproton beam has been determined using track density. We have also found tracks in the etched CR-39 detector at different depths (250-500 mum). These tracks have resulted from the annihilation of antiprotons with the constituents (H, C and O) of the CR-39 detector. The goal of the experiment is to develop a simple and low-cost method to study properties of antiparticles and those formed after annihilation of these particles with the target matter.

International Nuclear Information System (INIS)

Measurements are made of the isomeric ratio for the (n,2n) and (#betta#,n) reactions on the neutron-deficient nuclei _9_2Mo, _9_0Zr, _8_6Sr and _7_4Se. A method is developed for calculating the isomeric ratio for a low excitation energy of the residual nucleus. The good agreement found between experimental results and calculations for the (#betta#,n) reaction confirms the choices of residual nucleus characteristics, transmission coefficients of neutrons emitted etc. used in the calculations. The results of a study of the (n,2n) reaction were used to find the spin dependences of nuclear level density in the excitation energy region approx. 14 MeV. (author).

International Nuclear Information System (INIS)

Potassium atoms in selected high-lying np Rydberg states (80 #<=# n #<=# 400) are being used as a tool to examine electron-polar molecule collisions at ultra-low energies (#approx#80 #mu#eV - 1 meV). This energy regime has not been investigated previously and is of interest because the corresponding electron de Broglie wavelength is large, #approx#1300 - 330 Angstrom, and because the collision time is comparable to the period of molecular rotation. A variety of target molecules has been studied, including simple rotors such as HF, and more complex species such as NH_3, CH_3I, CH_2Br_2 and C_6H_5NO_2. These targets encompass a range of dipole moments and rotational behavior, but analysis of the data shows that in each case the cross section #sigma#(#epsilon#) for rotationally-inelastic electron-polar molecule scattering varies approximately as 1/#epsilon# where #epsilon# is the electron energy. ...

Energy Technology Data Exchange (ETDEWEB)

Delayed-neutron (DN) energy spectra following thermal neutron induced fission of /sup 239/Pu as a function of time after fission have been measured, using the beta-neutron time-of-flight (TOF) spectrometer at the University of Lowell. Thermal/epithermal neutrons were produced on the 5.5-MV Van de Graaff accelerator using the /sup 7/Li(p,n)/sup 7/Be reaction. Time spectra over the neutron energy range of 0.01-4.0 MeV were measured for seven different time intervals after fission, each interval containing varying contributions from the six delayed neutrons groups. The DN energy spectra following induced thermal fission of /sup 239/Pu are compared to those resulting from induced thermal fission of /sup 235/U for each of the seven delay time intervals. Decomposition of the measured spectra into six-group DN spectra was accomplished employing an iterative least-squares method, incorporating a constraint ...

Energy Technology Data Exchange (ETDEWEB)

The compositions of passive films formed on Fe-17Fr-13Ni (at. %) and Fe-18.5Cr-14Ni-1.5Mo (100) single crystals have been determined and the structure of the alloy under the film has been investigated. The alloys were passivated in 0.05M H{sub 2}SO{sub 4} at 250 mV/SHE for 30 min. The oxygen content was measured by nuclear microanalysis using the {sup 16}O(d,p) {sup 17}O* reaction. The oxygen content in the passive film is similar for the two alloys and equal to (12{plus minus}2) 10{sup 15} O/cm{sup 2}. The cationic compositions of the passive films have been determined by {sup 4}He channeling at two incident beam energies: 0.8 and 2.0 MeV. For the two alloys studied, a total cation content of (5{plus minus}2)10{sup 15} at/cm{sup 2} is found in the passive films. The corresponding thickness is about 12 A. There is an excess of oxygen, which can be attributed to the presence of hydroxyls and sulfate. A strong chromium enrichment is found in the ...

International Nuclear Information System (INIS)

Increasing frequency of skin cancer, mycosis fungoides, Kaposi sarcoma etc, it need to treatment dose planning for total skin electron beam (TSEB) therapy. Appropriate treatment planning for TSEB therapy is needed to give homogeneous dose distribution throughout the entire skin surface. The energy of 6 MeV electron from the 18 MeV medical linear accelerator was adapted for superficial total skin electron beam therapy. The energy of the electron beam was reduced to 4.2 MeV by a 0.5cmx90cmx180cm acryl screen placed in a feet front of the patient. Six dual field beam was adapted for total skin irradiation to encompass the entire body surface from head to toe simultaneously. The patients were treated behind the acryl screen plate acted as a beam scatterer and contained a parallel-plate shallow ion chamber for dosimetry and beam monitoring. During treatment, the patient was placed in six ...

International Nuclear Information System (INIS)

During the last decade, new radiopharmaceutical have been introduced for brain imaging. The marked differences of these tracers in tissue specificity within the brain and their increasing use for diagnostic studies support the need for a more anthropomorphic model of the human brain and head. Brain and head models developed in the past have been only simplistic representations of this anatomic region. For example, the brain within the phantom of MIRD Pamphlet No. 5 Revised is modeled simply as a single ellipsoid of tissue With no differentiation of its internal structures. To address this need, the MIRD Committee established a Task Group in 1992 to construct a more detailed brain model to include the cerebral cortex, the white matter, the cerebellum, the thalamus, the caudate nucleus, the lentiform nucleus, the cerebral spinal fluid, the lateral ventricles, and the third ventricle. This brain model has been included within a slightly modified version of the head model developed by ...

Energy Technology Data Exchange (ETDEWEB)

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

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.

International Nuclear Information System (INIS)

The differential recoil cross sections of H have been determined for 1.5-3.0 MeV He"+ incidence. In order to obtain precise data, we have performed simultaneous detection and spectrum simulation of recoiled H and backscattered He. In addition, a careful cross check has been made by secondary ion mass spectrometry (SIMS). The present results have revealed a pronounced contribution from a nuclear short-range interaction. The He"+ energy and recoil angle dependence of the H recoil cross sections are well reproduced by adding the nuclear term, which is simply derived from effective range theory. Our computer simulation program of elastic recoil combined with Rutherford backscattering spectra makes it possible to determine the depth distributions of H together with other elements absolutely, without any ambiguities. The present elastic recoil analysis is employed to determine the H composition of amorphous Si(H) films deposited on Si wafers. An ...

International Nuclear Information System (INIS)

The optoelectronic compounds of GaAs and ZnSe are difficult to analyze by PIXE (particle-induced X-ray emission) due to the strong absorption of the As and Se K_#alpha# X-rays. As part of a program to investigate optoelectronic materials using ion beam techniques, we have explored the possibility of using the high sensitivity of PIXE to check these materials for stoichiometry and dopant concentrations. The K_#alpha# X-ray intensity ratios of Ga to As and Zn to Se have been investigated using H beams of 0.5 to 2.5 MeV and He beams of 1.0 to 2.5 MeV. The variation in the X-ray intensity ratio with beam energy and target thickness is modelled in terms of the cross section for X-ray production and the absorption coefficients of the X-rays in the target. The results of this model show the experimental conditions that must be satisfied in order that the X-ray intensity ratios are not strongly affected by X-ray absorption; and ...

Energy Technology Data Exchange (ETDEWEB)

Thin Fe and Ta layers of 30-45 nm thickness, deposited via magnetron sputtering on Si (1 0 0) substrates, were bombarded at room temperature with 100 keV Ar{sup 1+} or Ar{sup 8+} or with 250 keV Xe{sup 1+} or Xe{sup 19+} ions in order to test the influence of the ion charge state on the surface sputtering and interface mixing. The samples were characterized by means of Rutherford backscattering at 0.9-3.0 MeV {alpha}-particle energy, time-of-flight elastic recoil detection analysis with a 53 MeV {sup 127}I{sup 10+} beam and atomic force microscopy. No influence of the charge state on the sputtering and athermal mixing rate was observed in the case of the Ta/Si system. However, in the case of the Fe/Si system, the ion charge was observed to have an influence on the mixing rate.

International Nuclear Information System (INIS)

There is an increasing interest in using radioisotopes of rare earth elements for internal radiotherapy and for imaging in nuclear medicine. "1"7"7Lu is one of the promising radionuclides. This article reports on the first measurements of the excitation function for the production of "1"7"7Lu with proton-beam energies up to 17 MeV on natural hafnium targets. The experimental cross sections for the reaction "n"a"tHf(p,x)"1"7"7Lu were obtained by the activation of a stacked-foil target and subsequent gamma spectrometry. Theoretical cross sections were calculated up to 35 MeV with the EMPIRE nuclear reaction model code. The measured and calculated cross sections were used for deriving the thick-target yields and for estimating the production of other nuclides than "1"7"7Lu. Measured production cross sections of "1"7"5","1"7"6","1"7"7","1"7"8Ta on the same target are also presented.

Energy Technology Data Exchange (ETDEWEB)

The personal neutron dosimetry becomes more important with the increasing use of nuclear and accelerator facilities. The solid state track detector, film badge and thermo-luminescent dosimeter have widely been used as passive-type personal neutron dosimeters, but the real-time neutron dosimeter is strongly needed. A real time personal dosimeter which could give neutron dose equivalent over wide energy range from thermal to 10 odd MeV by using two neutron sensors has been developed by our group. For practical commercial product, some changes from these prototype sensors have recently been done by Fuji Electric Co. Ltd. The purpose of this work is the final performance test of the dosimeter just before sale. We checked again about the sensitivity in the monoenergetic neutron field from 8 keV to 15 MeV and in the neutron fields around a few accelerator facilities. (author)

International Nuclear Information System (INIS)

The "2"0 "2"1 "2"2Ne("6Li, d)"2"4 "2"5 "2"6Mg reactions have been studied at a bombarding energy of 32 MeV. Alpha particle spectroscopic strengths have been extracted for several low-lying levels by a finite-range distorted wave analysis. These are compared with theoretical predictions. The agreement is good both for relative strengths to different levels within a nucleus and for ground-state strengths relative to the "1"6O("6Li, d) result. Strengths calculated using eigenfunctions determined in large shell-model computations agree well with pure symmetry SU(3) predictions. The "2"1Ne("6Li, d) angular distributions for transitions to the ground-state band of "2"5Mg are characterized by the lower of the two L-transfers allowed for populating each level. For the 3"+(5.24 MeV) unnatural parity level in "2"4Mg, a two-step calculation gives a better account of the data than does a compound nuclear calculation. (Auth.).

International Nuclear Information System (INIS)

Cross sections for (n,2n) (n,p) (n,#alpha#), and (n,d*)"1 reactions have been measured on ruthenium isotopes at the neutron energies of 13.5 to 14.8 MeV using the activation technique in combination with high-resolution gamma-ray spectroscopy. Data are reported for the following reactions: "1"0"4Ru(n,2n)"1"0"3Ru, "9"8Ru(n,2n)"9"7Ru, "9"6Ru(n,2n)"9"5Ru, "9"6Ru(n,p)"9"6Tc"g, "9"6Ru(n,p)"9"6Tc"m, "1"0"4Ru(n,p)"1"0"4Tc, "1"0"2Ru(n,p)"1"0"2Tc"m, "1"0"4Ru(n,#alpha#)"1"0"1Mo, "1"0"2Ru(n,#alpha#)"9"9Mo, "9"6Ru(n,#alpha#)"9"3Mo"m, and "9"6Ru(n,d*)"9"5Tc"m. Results were discussed and compared with the previous works.

International Nuclear Information System (INIS)

Complete energy spectra and angular distributions of the light charged particles (A < or = 4) were measured for the bombardment of "2"7Al, "5"8Ni, "9"0Zr, "2"0"9Bi, and "2"3"2Th with 140 MeV #alpha# particles. The spectral shapes of a given emitted particle are very similar for all target nuclei except in the region of the evaporation peak. The slopes of the energy spectra in the forward direction become steeper as the mass of the observed particle decreases and vary very rapidly with angles. The experimental data can be characterized by compound nuclear evaporation processes at low energies, or at backward angles, and by direct reactions, nonequilibrium components and projectile breakup processes at high energies and forward angles. The breakup cross section for #alpha# particles is found to be appreciable. The total yield of light charged particles is approximately a factor ...

International Nuclear Information System (INIS)

Two-dimensional calculations are performed to obtain the conversion efficiency of traveling wave direct energy convertor adopted in a conceptual design of field reversed configuration D-"3He fusion reactor ARTEMIS. For fusion-born 14.67MeV protons, the efficiency obtained is very small compared with that from one-dimensional analysis. This is because the effective electric field for deceleration of the proton is smaller due to distortion of potentials near girds used to excite the traveling wave and because some fractions of the incident proton beams are inevitably lost to the grids with high energy. To increase the efficiency, the potentials may have to be increased. It seems from the two-dimensional analysis performed here that the conversion efficiency obtainable is less than about 60% with the maximum potential of about 6MV, while the corresponding values from the one-dimensional analysis are about 80% and 1.5MV, ...

International Nuclear Information System (INIS)

A high power Free-Electron Laser (FEL) has lased at a wavelength of 22 #mu#m at the Japan Atomic Energy Research Institute (JAERI). The maximum power on a macro-pulse average is 1.7 kW, and it corresponds to an FEL energy of 160 #mu#J/micro-pulse. Extraction efficiency from the electron beam to the FEL radiation was measured to be 5.3% by an energy analyzer, when the maximum FEL power was coupled out. The rms wavelength spread was measured to be 4.6% at the same time. The extraction efficiency, in general, has a maximum value near the zero detuning length of an optical cavity, where (in contrast) the single-pass gain becomes smallest. A high peak current and a long macro-pulse duration are therefore indispensable for realizing high efficiency. The electron beam energy is 16.5 MeV, and the average current is 5.3 mA at a micro-pulse repetition rate of 10.4 MHz. The macro-pulse ...

International Nuclear Information System (INIS)

... functions intermediate structure isobaric analogs level widths mev range

International Nuclear Information System (INIS)

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

Energy Technology Data Exchange (ETDEWEB)

The excitation function of the {sup 64}Ni({alpha},p){sup 67}Cu reaction was measured from threshold up to 24 MeV in order to investigate the possibility of production of the {beta}{sup -}-emitting therapeutic radioisotope {sup 67}Cu (T{sub 1/2}=61.9 h). Two stacks of thin metallic self-supporting foils of {sup 64}Ni (enrichment 77.8%) prepared by electrolytic deposition were irradiated by {alpha}-particle beams. The radioactivity was determined via HPGe detector {gamma}-ray spectrometry. Some {sup 67}Ga activity (which emits the same {gamma}-rays as {sup 67}Cu), formed via the {sup nat}Cu({alpha},x){sup 67}Ga process on trace copper impurity in the Ni foils, was also observed. Corrections were done for {sup 67}Ga activity contribution and for the {sup 67}Cu activity escape fraction from the thin Ni-foil. The maximum cross section of the {sup 64}Ni({alpha},p){sup 67}Cu reaction amounts to 34 mb at 22 MeV. The experimental results were compared ...

Energy Technology Data Exchange (ETDEWEB)

It has often been proposed that track diameter in etched detectors can be used for energy spectrometry. To test this proposition, the relationship between track diameter and energy of alpha particles, in the range 0.1-5.5 MeV, incident on CR-39 was studied. Two sets of detectors were irradiated by a collimated normally-incident beam of {alpha}-particles of different energies, using an Am-241 source. Different foils of the first set were etched for variable lengths of time in such a way that, in each case, the etchant reached the end of the latent track. Foils in the second set were etched for a fixed 'short' time of 2 h, for all {alpha}-energies. The linear rate of energy loss as well as the residual range of {alpha}-particles was determined by using Henke and Benton's computer program. It is found that, for 'short' ...

International Nuclear Information System (INIS)

The studies using phantoms confirmed that the reduction of electron beam energy and minimization of X-ray contamination could be achieved when electron beam was interposed by an acrylic plate placed 20 cm anterior to a patient. Four patients of mycosis fungoides were treated with 8 MeV electron beam of a linear accelerator at UOEH Hospital from October 1981 to December 1986. Two of them were treated with this technique by placing 2 cm thick acrylic plate anterior to the patients and satisfactory results were obtained. Cutaneous lesions subsided remarkably with the dosage of 2000 cGy given in 2 months. Leucopenia due to bone marrow suppression was mild and the patients tolerated the treatment well. (author).

Energy Technology Data Exchange (ETDEWEB)

In April and May of 1999 the Berkeley Gas-filled Separator was used to search for the production and decay of element 118 from the {sup 86}Kr + {sup 208}Pb reaction, according to Smolanczuk's predictions of relatively large production rates. Three decay chains, each consisting of an implanted heavy ion, followed by a rapid (ms) succession of high-energy (>10 MeV) alpha-particle decays were detected. These chains are consistent with the production and decay of element 118 with mass number 293. These results a) show experimental evidence for the existence of shell-stabilized superheavy elements, b) provide experimental values for refinement of nuclear mass models in the superheavy element region, and, most importantly, c) present a new' reaction pathway for the production of superheavy elements. (author)

International Nuclear Information System (INIS)

The neutron-rich Mn isotopes from A=59 to 63 have been studied through multi-nucleon transfer reactions by bombarding a "2"3"8U target with a beam of "7"0Zn at an energy of E_l_a_b=460 MeV. Prompt #gamma# rays measured by the CLARA array have been identified unambiguously for each nucleus, using coincidence relationships with ions detected in the high-acceptance magnetic spectrometer PRISMA. The new data extends the knowledge of the low-lying level structure of Mn isotopes, which is discussed in terms of the systematics of the region. Results are compared with large-scale shell-model calculations using different effective interactions and valence spaces.

International Nuclear Information System (INIS)

Results of experimental investigation into radiation electromagnetic effect (REM) in samples of germanium crystals under approximately 40 MeV #alpha#-particle irradiation in a cyclotron are presented. A high level of excitation, volumetric character of generation of non-equilibrium carriers and formation of defects as well as the form of their spatial distribution are shown to result in some peculiarities of the EMF of the REM effect on the particle flux, fluence and sample parameters. Agreement of theoretical calculations, conducted with account of specificity of #alpha#-particle interaction with a crystal, and experimental data is obtained. It is revealed that the REM effect can be applied in obtaining data on spatial distribution of non-equilibrium carrier concentrations along the particle trajectory in the crystal.

International Nuclear Information System (INIS)

The newly discovered oxypnictide family of superconductors show very high critical temperatures of up to 55 K. Whilst there is growing evidence that suggests a nodal order parameter, point contact Andreev reflection spectroscopy can provide crucial information such as the gap value and possibly the number of energy gaps involved. For the oxygen deficient NdFeAsO_0_._8_5 with a T_c of 45.5 K, we show that there is clearly a gap value at 4.2 K that is of the order of 7 meV, consistent with previous studies on oxypnictides with lower T_c. In addition, taking the spectra as a function of gold tip contact pressure reveals important changes in the spectra which may be indicative of more complex physics underlying this structure. (rapid communication)

International Nuclear Information System (INIS)

We present the design, analysis, and results of the high brightness electron beam experiments currently under investigation at Sandia National Laboratories. The anticipated beam parameters are the following: energy 12 MeV, current 35 endash 40 kA, rms radius 0.5 mm, and pulse duration 40 ns full width at half-maximum. The accelerator is SABRE, a pulsed linear inductive voltage adder modified to higher impedance, and the electron source is a magnetically immersed foilless electron diode. 20 endash 30 T solenoidal magnets are required to insulate the diode and contain the beam to its extremely small-sized (1 mm) envelope. These experiments are designed to push the technology to produce the highest possible electron current in a submillimeter radius beam. Design, numerical simulations, and experimental results are presented. copyright 1997 American Institute of Physics.

International Nuclear Information System (INIS)

The effect of high energy neutron (E greater than 1 MeV) irradiation at 60"0C on the superconducting critical temperature, T/sub c/, the upper critical field, H/sub c2/, the lattice parameter, a_0, and the degree of Long Range Order has been measured for Nb and V based A-15 superconducting compounds. Large reductions in T/sub c/"0 and H/sub c2/ are observed for fluences up to 5.0 x 10"1"9 n/cm"2. For Nb_3Al, a_0 increases and the degree of Long Range Order is significantly reduced as T/sub c/ is depressed. Results are discussed in terms of atomic ordering in the A-15 structure.

Energy Technology Data Exchange (ETDEWEB)

At Los Alamos, we are building a free-electron laser (FEL) for industrial, medical, and research applications. This FEL, which will incorporate many of the new technologies developed over the last decade, will be compact in size, robust, and user-friendly. Electrons produced by a photocathode will be accelerated to 20 MeV by a high-brightness accelerator and transported using permanent-magnet quadrupoles and dipoles. They will form an electron beam with an excellent instantaneous beam quality of 10 {pi} mm mrad in transverse emittance and 0.3% in energy spread at a peak current up to 300 A. Including operation at higher harmonics, the laser wavelength extends form 3.7 {mu}m to 0.4 {mu}m. In this paper, we will describe the project and the programs to date. 10 refs., 10 figs., 1 tab.

International Nuclear Information System (INIS)

It has recently been shown that the superconducting properties of Nb-base A-15 compounds, A_3B, are severely degraded when exposed to high-energy (E>1 MeV) neutron irradiation at ambient reactor temperatures. In each case, superconducting transition temperatures, Tsub(c), and the Bragg Williams order parameters, S, were observed to decrease steadily with irradiations in excess of 10"1"8 nvt. During irradiation the A-15 structure is retained and subsequent isothermal annealing restores almost completely the compound's original Tsub(c) value. In this letter a correlation between B atom diameter and the recovery rates of Tsub(c) for the irradiated materials Nb_3Ge, Nb_3Ga, Nb_3Al and Nb_3Sn is reported. (Auth.).

International Nuclear Information System (INIS)

N-type crystalline Si (100) implanted with 5 keV B ions was subsequently irradiated with MeV Si, O and F ions. The B atom profiles were measured by means of secondary ion mass spectrometer after the treatment of rapid thermal annealing. The results show that the transient enhanced diffusion of B atoms is effectively limited by the post-implantation of high energy ions at high dose. At the same irradiation conditions, it is found that the existence of a SiO_2 layer in the near surface of Si is even more effective in suppressing the transient enhanced diffusion of the doped B atoms. The results are qualitatively discussed in combination with the analyses of RBS/c measurements and calculation of the DICADA code

Energy Technology Data Exchange (ETDEWEB)

In this paper, the design of large thin PIN detector with a membrane stress avoidance configuration is proposed, and the related device fabrication process is developed. Ultra-thin PIN detector {approx} 1.13 cm{sup 2} in area is fabricated on a thin ( {approx} 35{mu}m) silicon membrane, and characterized. Detector performance improvement has been successfully demonstrated. With the membrane stress avoidance design, the improved detector exhibits a leakage of 6nA, which is at least 5 times lower than that of detector of identical junction area. The new detector features a full depleted capacitance of 110 pF, and a FWHM of 40.86 keV energy resolution for 5.486 MeV alpha particle spectrography.

International Nuclear Information System (INIS)

Comparisons of calculated neutron yield distributions from #alpha#-particle induced reactions on thick targets are made with measured data to analyze the initial reaction process in the framework of the exciton (hybrid) model code ALICE91 (M. Blann, Lawrence Livermore National Laboratory Report UCID 19614, 1982). We have considered two reaction mechanisms: dissolution of the #alpha# in the nuclear field, and preequilibrium processes initiated by #alpha#-nucleon collisions. Both these processes seem to contribute to the emitted neutron spectra in varying proportions depending on the incident #alpha# energy and possibly on the target nucleus. Contributions from other processes appear to be non-negligible.

British Library Electronic Table of Contents (United Kingdom)

Abstract We suggest a simple scheme for automatically determining the width parameter of smearing methods of the Brillouin zone integration in electronic structure calculation. The scheme retains one free parameter that at any time can be eliminated by choosing a denser k-space mesh until the desired accuracy is obtained. The tests are carried out in the context of Methfessel-Paxton smearing. This adaptive Gaussian smearing (AGS) is easily implemented, variational with respect to partial occupancies and free from spurious occupancies that are negative or larger than one. Its convergence properties are similar to those obtained with the modified tetrahedron method for energy resolution of -0.1 meV. 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011

Science.gov (United States)

The /sup 86,88/Sr(d, /sup 3/He)/sup 85,87/Rb reactions were studied at energy of 28 MeV and angular distributions were obtained for all observed states. Spectroseopic factors were extracted from distorted-wave Born-approximation calculations of the cross sections. These spectroacopic factors, and those from the /sup 86,88/Sr(/sup 3/He, d)/sup 87,89/ Y reactions, mixing in the ground state of /sup 88/Sr is inferred. The two g/sub (9/2) neutro n ton orbital populations in /sup 86/Sr. (auth)

Energy Technology Data Exchange (ETDEWEB)

Several reactions producing odd-Z transactinide compound nuclei were studiedwith the 88-Inch Cyclotron and the Berkeley Gas-Filled Separator at the LawrenceBerkeley National Laboratory. The goal was to produce the same compound nucleus ator near the same excitation energy with similar values of angular momentum via differentnuclear reactions. In doing so, it can be determined if there is a preference in entrancechannel, because under these experimental conditions the survival portion of Swiatecki, Siwek-Wilcznska, and Wilczynski's"Fusion By Diffusion" model is nearly identical forthe two reactions. Additionally, because the same compound nucleus is produced, theexit channel is the same. Four compound nuclei were examined in this study: 258Db, 262Bh, 266Mt, and 272Rg. These nuclei were produced by using very similar heavy-ion induced-fusion reactions which differ only by one proton in the projectile or target nucleus (e.g.: 50Ti + 209Bi vs. ...

International Nuclear Information System (INIS)

Inelastic scattering of #alpha#-particles in 22-24 MeV energy range on "1"8o o, "1"9f, "2"0Ne, "2"2Ne nuclei is investigated. Measurements of excitation functions were conducted for the beam of Leningrad University cyclo otron at several angles in 15-165 deg range of laboratory system with 2.5 deg spacing. The error of determining absolute cross sections equals +-20% for "2"2Ne and +-12% for other nuclei. Angular distributions have the differaction character, are similar in form for all nuclei, the values of differential cross- -sections don't exceed the rutherford values. The dependence of integral cross-sections on the energy of level excitation is similar to the exponential d dependence of cross-sections of production of the given element isotopes on the gergy difference of masses of final nuclear products in the reactions of deeply inelastic transfers with heavy ions. The observed isotopic effect in the value of ...

International Nuclear Information System (INIS)

The #gamma#-ray spectrum emitted after thermal neutron capture in "8"7Sr was studied at the ILL high flux reactor with pair- and intrinsic Ge-spectrometers. 661 transitions were assigned to the reaction "8"7Sr(n,#gamma#)"8"8Sr and 205 of them were placed into a "8"8Sr level scheme of 47 levels. This represents 88% of the observed intensity. The level energies were determined with a precision of better than 22 ppm; the neutron binding energy was determined as 11 112.69 (22) keV. To aid the analysis high resolution particle spectra of the reaction "8"7Sr(d,p)"8"8Sr were measured at 20 MeV deuteron energy with the Munich Q3D spectrometer. 85 states were observed with this reaction. The data helped to establish newly found levels and to differentiate between primary and secondary transitions in the (n,#gamma#) data. The observed level densities and primary transition strengths are compared with statistical ...

Energy Technology Data Exchange (ETDEWEB)

We have performed inelastic neutron scattering (INS) experiments on CeRh{sub 3}B{sub 2} at various temperatures to obtain direct information on the crystal electric field (CEF) in this compound, which exhibits some very peculiar magnetic properties for a Ce system: it is ferromagnetic with an unusually high Curie temperature (115 K), which contrasts with a strongly reduced and anisotropic magnetization (0.4 {mu}{sub B}/fu within the c-plane of the hexagonal structure). Measurements with high incident energies show only one well defined magnetic excitation around 150 meV, its exact position varying with the temperature. These results, combined with our previous data of magnetization and magnetic form factor, have permitted us to determine the CEF energy level scheme taking into account the two J multiplets of the Ce{sup 3+} ion. Information on the ground state (quasielastic contribution and ground state moment) has also been ...

Energy Technology Data Exchange (ETDEWEB)

A G-matrix, derived from a meson-exchange potential in nuclear matter, is applied to finite, semi-magic nuclei. For the open shell the broken-pair model, which can accommodate many single-particle levels, is used. The excitations of the closed shell are treated as particle-hole states. Energy spectra and electromagnetic transition densities are calculated for /sup 88/Sr and /sup 58/Ni. The energies of the non-collective states are well described. Pairing correlations in the ground state have almost the correct strength in a multishell model space. To improve the energies of the collective 2/sup +/ and 3/sup -/ states the inclusion of core-polarisation effects in the force is required. Transition charge densities for collective states become strongly surface-peaked by core-polarisation effects, as is observed in experiments. The effects of pairing correlations and core polarisation on the magnetic form factor of the 3.486 ...

International Nuclear Information System (INIS)

The National Bureau of Standards' (NBS) CW racetrack microtron (RTM) will be utilized as a driver for a free electron laser (FEL) oscillator. The NBS RTM possesses many exceptional properties of value for the FEL: i) CW operation, ii) energy from 20-185 MeV, iii) small energy spread and emittance, iv) excellent energy stability, and v) high average power. The 1-D FEL gain formula predicts that the FEL would oscillate at the fundamental approximately from 0.25 #mu#m to 10 #mu#m when up-grading the peak current to #>=# 2 A. In this paper, the authors present 3-D self-consistent numerical results including several realistic effects, such as emittance, betatron oscillations, diffraction and refraction. The results indicate that the design value of the transverse emittance is small enough that it does not degrade the FEL performance for intermediate to long wavelengths, and only slightly degrades the ...

Energy Technology Data Exchange (ETDEWEB)

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International Nuclear Information System (INIS)

... 3 reactions mev range 10-100 neutron spectra neutrons nuclear reaction