Consequences of a 17-keV neutrino

International Nuclear Information System (INIS)

Caldwell, D.O.; Langacker, P.

1991-01-01

If the controversial 17-keV neutrino exists, laboratory, astrophysical and cosmological bounds, unless significantly weakened, require that (1) it be a Majorana neutrino and mainly ν τ ; (2) it not be the dark matter of the universe, although its existence would rule out dominant hot dark matter; (3) the ν μ be a heavy Majorana neutrino of mass 17 keV or in the range 170--270 keV; and (4) the Mikheyev-Smirnov-Wolfenstein solution to the solar-neutrino problem involve ν e conversion to a light sterile [SU(2)-singlet] neutrino

A comparative study of inelastic scattering models at energy levels ranging from 0.5 keV to 10 keV

Energy Technology Data Exchange (ETDEWEB)

Hu, Chia-Yu [Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan (China); Lin, Chun-Hung, E-mail: chlin@mail.ncku.edu.tw [Department of Photonics, National Cheng Kung University, Tainan 701, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China)

2017-03-01

Six models, including a single-scattering model, four hybrid models, and one dielectric function model, were evaluated using Monte Carlo simulations for aluminum and copper at incident beam energies ranging from 0.5 keV to 10 keV. The inelastic mean free path, mean energy loss per unit path length, and backscattering coefficients obtained by these models are compared and discussed to understand the merits of the various models. ANOVA (analysis of variance) statistical models were used to quantify the effects of inelastic cross section and energy loss models on the basis of the simulated results deviation from the experimental data for the inelastic mean free path, the mean energy loss per unit path length, and the backscattering coefficient, as well as their correlations. This work in this study is believed to be the first application of ANOVA models towards evaluating inelastic electron beam scattering models. This approach is an improvement over the traditional approach which involves only visual estimation of the difference between the experimental data and simulated results. The data suggests that the optimization of the effective electron number per atom, binding energy, and cut-off energy of an inelastic model for different materials at different beam energies is more important than the selection of inelastic models for Monte Carlo electron scattering simulation. During the simulations, parameters in the equations should be tuned according to different materials for different beam energies rather than merely employing default parameters for an arbitrary material. Energy loss models and cross-section formulas are not the main factors influencing energy loss. Comparison of the deviation of the simulated results from the experimental data shows a significant correlation (p < 0.05) between the backscattering coefficient and energy loss per unit path length. The inclusion of backscattering electrons generated by both primary and secondary electrons for

Using the Medipix3 detector for direct electron imaging in the range 60 keV to 200 keV in electron microscopy

Science.gov (United States)

Mir, J. A.; Plackett, R.; Shipsey, I.; dos Santos, J. M. F.

2017-11-01

Hybrid pixel sensor technology such as the Medipix3 represents a unique tool for electron imaging. We have investigated its performance as a direct imaging detector using a Transmission Electron Microscope (TEM) which incorporated a Medipix3 detector with a 300 μm thick silicon layer compromising of 256×256 pixels at 55 μm pixel pitch. We present results taken with the Medipix3 in Single Pixel Mode (SPM) with electron beam energies in the range, 60-200 keV . Measurements of the Modulation Transfer Function (MTF) and the Detective Quantum Efficiency (DQE) were investigated. At a given beam energy, the MTF data was acquired by deploying the established knife edge technique. Similarly, the experimental data required to determine DQE was obtained by acquiring a stack of images of a focused beam and of free space (flatfield) to determine the Noise Power Spectrum (NPS).

Development of a flat-field spectrometer with a wideband Ni/C multilayer grating in the 1–3.5 keV range

Energy Technology Data Exchange (ETDEWEB)

Imazono, Takashi [Quantum Beam Science Center, Japan Atomic Energy Agency, 8-1-7, Umemidai, Kizugawa, Kyoto 619-0216 (Japan)

2016-07-27

To develop a flat-field spectrometer with coverage of the 1–3.5 keV range, a wideband Ni/C multilayer grating was invented. The multilayer consists of two kinds of layer structures. One is a conventional periodic multilayer of thickness D{sub 1} = 5.6 nm, Ni thickness ratio to the multilayer period γ{sub 1} = 0.5 and the number of layers N{sub 1} = 79. Both the first and last layers are Ni. The other is a C/Ni bilayer of D{sub 2} = 8.4 nm, γ{sub 2} = 0.53 and N{sub 2} = 2. The first layer is C and then Ni. The aperiodic multilayer from the topmost C/Ni bilayer was coated on a laminar-type grating having an effective grating constant of 1/2400 mm, groove depth of 2.8 nm, and duty ratio (land width/groove period) of 0.5. In a preliminary experiment, the diffraction efficiency was in excess of 0.8% in the energy range of 2.1-3.3 keV and the maximum of 5.4% at 3.1 keV at a constant angle of incidence of 88.54°, which is considerably higher than that of an Au-coated grating before deposition of the multilayer.

Neutron fluence and energy reconstruction with the IRSN recoil detector μ-TPC at 27 keV, 144 keV and 565 keV

Energy Technology Data Exchange (ETDEWEB)

Maire, D.; Lebreton, L.; Richer, J.P. [IRSN, PRP-HOM, SDE, LMDN, 13115 Saint Paul-Lez-Durance (France); Bosson, G.; Bourrion, O.; Guillaudin, O.; Riffard, Q.; Santos, D. [CNRS/IN2P3-UJF-INPG, LPSC, 38000 Grenoble (France)

2015-07-01

The French Institute for Radioprotection and Nuclear Safety (IRSN), associated to the French Metrology Institute (LNE), is developing a time projection chamber using a Micromegas anode: μ-TPC. This work is carried out in collaboration with the Laboratory of Subatomic Physics and Cosmology (LPSC). The aim is to characterize with a primary procedure the energy distribution of neutron fluence in the energy range 8 keV - 1 MeV. The time projection chambers are gaseous detectors, which are able to measure charged particles energy and to reconstruct their track if a pixelated anode is used. In our case, the gas is used as a (n, p) converter in order to detect neutrons down to few keV. Coming from elastic collisions with neutrons, recoil protons lose a part of their kinetic energy by ionizing the gas. The ionization electrons are drifted toward a pixelated anode (2D projection), read at 50 MHz by a self-triggered electronic system to obtain the third track dimension. The neutron energy is reconstructed event by event thanks to proton scattering angle and proton energy measurements. The scattering angle is deduced from the 3D track. The proton energy is obtained by charge collection measurements, knowing the ionization quenching factor (i.e. the part of proton kinetic energy lost by ionizing the gas). The fluence is calculated thanks to the detected events number and the simulated detector response. The μ-TPC is a new reliable detector which enables to measure energy distribution of the neutron fluence without deconvolution or neutron calibration contrary to usual gaseous counters. The μ-TPC is still being developed and measurements have been carried out at the AMANDE facility, with neutrons energies going from 8 keV to 565 keV. After the context and the μ-TPC working principle presentation, measurements of the neutron energy and fluence at 27.2 keV, 144 keV and 565 keV are shown and compared to the complete detector simulation. This work shows the first direct

Measurement of the mass energy-absorption coefficient of air for x-rays in the range from 3 to 60 keV.

Science.gov (United States)

Buhr, H; Büermann, L; Gerlach, M; Krumrey, M; Rabus, H

2012-12-21

For the first time the absolute photon mass energy-absorption coefficient of air in the energy range of 10 to 60 keV has been measured with relative standard uncertainties below 1%, considerably smaller than those of up to 2% assumed for calculated data. For monochromatized synchrotron radiation from the electron storage ring BESSY II both the radiant power and the fraction of power deposited in dry air were measured using a cryogenic electrical substitution radiometer and a free air ionization chamber, respectively. The measured absorption coefficients were compared with state-of-the art calculations and showed an average deviation of 2% from calculations by Seltzer. However, they agree within 1% with data calculated earlier by Hubbell. In the course of this work, an improvement of the data analysis of a previous experimental determination of the mass energy-absorption coefficient of air in the range of 3 to 10 keV was found to be possible and corrected values of this preceding study are given.

Measurement of the 232Th neutron capture cross section in the region 5 keV-150 keV

International Nuclear Information System (INIS)

Lobo, Georges; Corvi, Franco; Schillebeeckx, Peter; Brusegan, Antonio; Mutti, Paolo; Janeva, Natalia

2002-01-01

The average capture cross-section of 232 Th has been measured at the 14.37 m flight path of GELINA, IRMM-Geel, in the energy range from 5 to 150 keV. The capture events were detected by two C 6 D 6 liquid scintillators and the neutron flux was measured with a 10 B-loaded ionisation chamber. The data, corrected with the pulse-height weighting technique, have been normalised to the well-isolated and nearly saturated 232 Th (n, γ) resonances at 21.8 eV and 23.5 eV. Below 15 keV neutron energy, we do not observe the discrepancies, up to 40%, with the evaluated ENDF/B-VI data as reported by Wisshak et al.. Between 5 and 80 keV our results are about 10% systematically above the ENDF/B-VI data and approach the evaluated data between 80 and 100 keV. (author)

Measurement of multilayer reflectivities from 8 keV to 130 keV

DEFF Research Database (Denmark)

Hoeghoej, P.; Joensen, K. D.; Christensen, Finn Erland

1993-01-01

This paper presents measurements of specular and non-specular reflectivities of a W/Si multilayer with period d=135.1 A. Angular dispersive measurements were performed at 8.05 keY and 59.3 keY, while energy dispersive measurements were made in the range of 17 keV to 130 keY. At an incidence angle...

Development and characterization of semiconductor ion detectors for plasma diagnostics in the range over 0.3 keV

Science.gov (United States)

Cho, T.; Sakamoto, Y.; Hirata, M.; Kohagura, J.; Makino, K.; Kanke, S.; Takahashi, K.; Okamura, T.; Nakashima, Y.; Yatsu, K.; Tamano, T.; Miyoshi, S.

1997-01-01

For the purpose of plasma-ion-energy analyses in a wide-energy range from a few hundred eV to hundreds of keV, upgraded semiconductor detectors are newly fabricated and characterized using a test-ion-beam line from 0.3 to 12 keV. In particular, the detectable lowest-ion energy is drastically improved at least down to 0.3 keV; this energy is one to two orders-of-magnitude better than those for commercially available Si-surface-barrier diodes employed for previous plasma-ion diagnostics. A signal-to-noise ratio of two to three orders-of-magnitude better than that for usual metal-collector detectors is demonstrated for the compact-sized semiconductor along with the availability of the use under conditions of a good vacuum and a strong-magnetic field. Such characteristics are achieved due to the improving methods of the optimization of the thicknesses of a Si dead layer and a SiO2 layer, as well as the nitrogen-doping technique near the depletion layer along with minimizing impurity concentrations in Si. Such an upgraded capability of an extremely low-energy-ion detection with the low-noise characteristics enlarges research regimes of plasma-ion behavior using semiconductor detectors not only in the divertor regions of tokamaks but in wider spectra of open-field plasma devices including tandem mirrors. An application of the semiconductor ion detector for plasma-ion diagnostics is demonstrated in a specially designed ion-spectrometer structure.

Characterizations of MCP performance in the hard x-ray range (6–25 keV)

Energy Technology Data Exchange (ETDEWEB)

Wu, Ming, E-mail: minwu@sandia.gov; Rochau, Greg [Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States); Moy, Ken [Special Technology Laboratories, NSTec, Santa Barbara, California 93111-2335 (United States); Kruschwitz, Craig [National Security Technologies, LLC, Los Alamos Operations, Los Alamos, New Mexico 87544 (United States)

2014-11-15

MCP detector performance at hard x-ray energies from 6 to 25 keV was recently investigated using NSLS beamline X15A at BNL. Measurements were made with an NSTec Gen-II (H-CA-65) framing camera, based on a Photonis MCP with ∼10 μm in diameter pores, ∼12 μm center-center spacing, an L/D ratio of 46, and a bias angle of 8°. The MCP characterizations were focused on (1) energy and angle dependent sensitivity, (2) energy and angle dependent spatial resolution, (3) energy dependent gain performance, and (4) energy dependent dynamic range. These measurement corroborated simulation results using a Monte Carlo model that included hard x-ray interactions and the subsequent electron cascade in the MCP.

Charge-transfer cross sections of ground state He+ ions in collisions with He atoms and simple molecules in the energy range below 4.0 keV

International Nuclear Information System (INIS)

Kusakabe, Toshio; Kitamuro, Satoshi; Nakai, Yohta; Tawara, Hiroyuki; Sasao, Mamiko

2012-01-01

Charge-transfer cross sections of the ground state He + ions in collisions with He atoms and simple molecules (H 2 , D 2 , N 2 , CO and CO 2 ) have been measured in the energy range of 0.20 to 4.0 keV with the initial growth rate method. Since previously published experimental data are scattered in the low energy region, the present observations would provide reasonably reliable cross section data below 4 keV. The charge transfer accompanied by dissociation of product molecular ion can be dominant at low energies for molecular targets. In He + + D 2 collisions, any isotope effect was not observed over the present energy range, compared to H 2 molecule. (author)

Sputtering of Thick Deuterium Films by KeV Electrons

DEFF Research Database (Denmark)

Thestrup Nielsen, Birgitte; Svendsen, Winnie Edith; Schou, Jørgen

1994-01-01

Sputtering of thick films of solid deuterium up to several μm by keV electrons is reported for the first time. The sputtering yield increases within a narrow range of thicknesses around 1.6 μm by about 2 orders of magnitude for 1.5 keV electrons. A similar behavior has not been observed for ion...

Interaction between Solid Nitrogen and 1-3-keV Electrons

DEFF Research Database (Denmark)

Schou, Jørgen; Sørensen, H.

1978-01-01

V. At 3 keV, the SEE coefficient is 12 times that for solid deuterium. This is attributed partly to the larger production rate for low-energy electrons in nitrogen and partly to the larger escape probability for these electrons. Moreover, measurements were made of the electron-reflection coefficient, both......Experimental studies were made of the interaction between solid nitrogen and beams of 1-2-keV electrons. The projected range for the electrons was measured by means of the mirror-substrate method (gold substrate), giving the result 9.02×1016 E1.75 molecules/cm2 with the energy given in ke...... for solid nitrogen and for the carbon substrate. For nitrogen, it varied from 0.17 el/el at 1 keV to 0.13 el/el at 3 keV, and for carbon it varied from 0.13 to 0.12. The observations are discussed and comparisons made with other theoretical and experimental results. The agreement ranges from good to fair...

Testing and Comparison of Imaging Detectors for Electrons in the Energy Range 10-20 keV

Science.gov (United States)

Matheson, J.; Moldovan, G.; Kirkland, A.; Allinson, N.; Abrahams, J. P.

2017-11-01

Interest in direct detectors for low-energy electrons has increased markedly in recent years. Detection of electrons in the energy range up to low tens of keV is important in techniques such as photoelectron emission microscopy (PEEM) and electron backscatter diffraction (EBSD) on scanning electron microscopes (SEMs). The PEEM technique is used both in the laboratory and on synchrotron light sources worldwide. The ubiquity of SEMs means that there is a very large market for EBSD detectors for materials studies. Currently, the most widely used detectors in these applications are based on indirect detection of incident electrons. Examples include scintillators or microchannel plates (MCPs), coupled to CCD cameras. Such approaches result in blurring in scintillators/phosphors, distortions in optical systems, and inefficiencies due the limited active area of MCPs. In principle, these difficulties can be overcome using direct detection in a semiconductor device. Growing out of a feasibility study into the use of a direct detector for use on an XPEEM, we have built at Rutherford Appleton Laboratory a system to illuminate detectors with an electron beam of energy up to 20 keV . We describe this system in detail. It has been used to measure the performance of a custom back-thinned monolithic active pixel sensor (MAPS), a detector based on the Medipix2 chip, and a commercial detector based on MCPs. We present a selection of the results from these measurements and compare and contrast different detector types.

Characterization of the PILATUS photon-counting pixel detector for X-ray energies from 1.75 keV to 60 keV

International Nuclear Information System (INIS)

Donath, T; Brandstetter, S; Commichau, S; Hofer, P; Lüthi, B; Schneebeli, M; Schulze-Briese, C; Cibik, L; Krumrey, M; Marggraf, S; Müller, P; Wernecke, J

2013-01-01

The PILATUS detector module was characterized in the PTB laboratory at BESSY II comparing modules with 320 μm thick and newly developed 450 μm and 1000 μm thick silicon sensors. Measurements were carried out over a wide energy range, in-vacuum from 1.75 keV to 8.8 keV and in air from 8 keV to 60 keV. The quantum efficiency (QE) was measured as a function of energy and the spatial resolution was measured at several photon energies both in terms of the modulation transfer function (MTF) from edge profile measurements and by directly measuring the point spread function (PSF) of a single pixel in a raster scan with a pinhole beam. Independent of the sensor thickness, the measured MTF and PSF come close to those for an ideal pixel detector with the pixel size of the PILATUS detector (172 × 172 μm 2 ). The measured QE follows the values predicted by calculation. Thicker sensors significantly enhance the QE of the PILATUS detectors for energies above 10 keV without impairing the spatial resolution and noise-free detection. In-vacuum operation of the PILATUS detector is possible at energies as low as 1.75 keV.

Characterization of the PILATUS photon-counting pixel detector for X-ray energies from 1.75 keV to 60 keV

Science.gov (United States)

Donath, T.; Brandstetter, S.; Cibik, L.; Commichau, S.; Hofer, P.; Krumrey, M.; Lüthi, B.; Marggraf, S.; Müller, P.; Schneebeli, M.; Schulze-Briese, C.; Wernecke, J.

2013-03-01

The PILATUS detector module was characterized in the PTB laboratory at BESSY II comparing modules with 320 μm thick and newly developed 450 μm and 1000 μm thick silicon sensors. Measurements were carried out over a wide energy range, in-vacuum from 1.75 keV to 8.8 keV and in air from 8 keV to 60 keV. The quantum efficiency (QE) was measured as a function of energy and the spatial resolution was measured at several photon energies both in terms of the modulation transfer function (MTF) from edge profile measurements and by directly measuring the point spread function (PSF) of a single pixel in a raster scan with a pinhole beam. Independent of the sensor thickness, the measured MTF and PSF come close to those for an ideal pixel detector with the pixel size of the PILATUS detector (172 × 172 μm2). The measured QE follows the values predicted by calculation. Thicker sensors significantly enhance the QE of the PILATUS detectors for energies above 10 keV without impairing the spatial resolution and noise-free detection. In-vacuum operation of the PILATUS detector is possible at energies as low as 1.75 keV.

The detection of hard x-rays (10-140 KeV) by channel plate electron multipliers

International Nuclear Information System (INIS)

Bateman, J.E.

1976-12-01

Results are presented indicating that hard X-rays in the energy range 10 to 50 keV can be detected with good efficiency (5 to 10%) in channel plate electron multipliers (CPEM). From 50 keV to 140 keV the detection efficiency lies in the range 1 to 2%. A simple physical model is developed which indicates that not only can good detection efficiency be obtained but that very good X-ray imaging is possible. The model predicts that with further development, a wideband, hard X-ray detector can be realised with a detection efficiency in the range 5 to 20% and spatial response better than 10 lp/mm in the energy range 10 to 140 keV. (author)

Characteristic K-shell x-ray production by protons below 500 keV

International Nuclear Information System (INIS)

Wheeler, R.M.; Chaturvedi, R.P.; Zander, A.R.

1974-01-01

The total thick target yield of K-shell x-rays produced in Ni by incident protons over the energy range 90 to 415 keV was measured. Similar measurements with 130 to 415 keV protons were made for Ti, Mn, Fe, Cu, and Zn. The East Texas State University 150 keV Cockcroft--Walton accelerator was used to study Ni K-shell x-rays produced by 90 to 150 keV protons. The remaining data were taken with the SUNY College at Cortland 400 keV Van de Graaff generator. The characteristic x-rays were measured with high resolution Si(Li) detectors. Using the most recent values of K-shell fluorescent yields, x-ray ionization cross sections were calculated and compared to theoretical predictions based on the binary encounter approximation (BEA) model. It was found that even though the data were lower than those expected by the BEA theory, they lie on a universal curve. A comprehensive summary of x-ray ionization cross section references covering the proton energy range up to 500 keV is also included. Possible applications of low energy accelerators (E/sub p/ less than or equal to 500 keV) for further experimental work is discussed

Construction, calibration and testing of a ionization chamber for exposure measurement of X and gamma rays in the energy range from 40 keV up to 1250KEV

International Nuclear Information System (INIS)

Campos, Carlos A.A. Lima

1982-01-01

An unsealed thimble ionization chamber with connecting cable was designed, manufactured and tested at the IRD/CNEN, for exposure or exposure rate measurement of X or gamma rays in the energy range from 40 keV up to Cobalt-60. Recommendations given by IEC,TC-62(1974) were used as acceptance tests of the ionization chamber for use as a tertiary standard (field class instruments) in radiation therapy. In addition, intercomparison with commercially available chambers of reference class type were carried out in respect to field size dependence, energy dependence, short and long term stability.The results of those tests indicated the usefulness of the developed ionization chamber as a tertiary standard. (author)

Neutron capture resonances in 56Fe and 58Fe in the energy range from 10 to 100 keV

International Nuclear Information System (INIS)

Kaeppeler, F.; Wisshak, K.; Hong, L.D.

1982-11-01

The neutron capture cross section of 56 Fe and 58 Fe has been measured in the energy range from 10 to 250 keV relative to the gold standard. A pulsed 3 MV Van de Graaff accelerator and the 7 Li(p, n) reaction served as a neutron source. Capture gamma rays were detected by two C 6 D 6 detectors, which were operated in coincidence and anticoincidence mode. Two-dimensional data acquisition allowed to apply the pulse height weighting technique off-line. The samples were located at a flight path of 60 cm. The total time resolution was 1.2 ns thus allowing for an energy resolution of 2 ns/m. The experimental set-up was optimized with respect to low background and low neutron sensitivity. The additional flight path of 4 cm from the sample to the detector was sufficient to discriminate capture of sample scattered neutrons by the additional time of flight. In this way reliable results were obtained even for the strong s-wave resonances of both isotopes. The experimental capture yield was analyzed with the FANAC code. The energy resolution allowed to extract resonance parameters in the energy range from 10 to 100 keV. The individual systematic uncertainties of the experimental method are discussed in detail. They were found to range between 5 and 10% while the statistical uncertainty is 3-5% for most of the resonances. A comparison to the results of other authors exhibits in case of 56 Fe systematic differences of 7-11%. For 58 Fe the present results differ up to 50% from the only other measurement for this isotope. (orig.) [de

Adjustment of a goniometer for X-rays optics calibration in the spectral range 1.5-20 KeV

International Nuclear Information System (INIS)

Legistre, S.

1992-10-01

The aim of this memoir is the adjustment of a (θ, 2θ) goniometer coupled to X-rays source to calibrate mirrors (single layers like C, Ni, Au, etc... and multilayers like C/W, Si/W, etc...) in the spectral range 1.5 - 20 keV. For each kind of tested optics the adjustment of the goniometer include the procedure alignment of the different components (X-ray source, collimation slits, optics, detectors) and the first reflectivity measurements. Those measurements are compared those realized at LURE, using synchrotron radiation provided by SUPER ACO storage ring, and to a theoretical simulation

Facilities and techniques for x-ray diagnostic calibration in the 100-eV to 100-keV energy range

International Nuclear Information System (INIS)

Gaines, J.L.; Wittmayer, F.J.

1986-01-01

The Lawrence Livermore National Laboratory (LLNL) has been a pioneer in the field of x-ray diagnostic calibration for more than 20 years. The authors built steady state x-ray sources capable of supplying fluorescent lines of high spectral purity in the 100-eV to 100-keV energy range, and these sources have been used in the calibration of x-ray detectors, mirrors, crystals, filters, and film. This paper discusses their calibration philosophy and techniques, and describes some of the x-ray sources. Examples of actual calibration data are presented as well

Facilities and Techniques for X-Ray Diagnostic Calibration in the 100-eV to 100-keV Energy Range

Science.gov (United States)

Gaines, J. L.; Wittmayer, F. J.

1986-08-01

The Lawrence Livermore National Laboratory (LLNL) has been a pioneer in the field of x-ray diagnostic calibration for more than 20 years. We have built steady state x-ray sources capable of supplying fluorescent lines of high spectral purity in the 100-eV to 100-keV energy range, and these sources have been used in the calibration of x-ray detectors, mirrors, crystals, filters, and film. This paper discusses our calibration philosophy and techniques, and describes some of our x-ray sources. Examples of actual calibration data are presented as well.

Facilities and techniques for x-ray diagnostic calibration in the 100-eV to 100-keV energy range

International Nuclear Information System (INIS)

Gaines, J.L.; Wittmayer, F.J.

1986-06-01

The Lawrence Livermore National Laboratory (LLNL) has been a pioneer in the field of x-ray diagnostic calibration for more than 20 years. We have built steady state x-ray sources capable of supplying fluorescent lines of high spectral purity in the 100-eV to 100-keV energy range, and these sources have been used in the calibration of x-ray detectors, mirrors, crystals, filters, and film. This paper discusses our calibration philosophy and techniques, and describes some of our x-ray sources. Examples of actual calibration data are presented as well

W/SiC X-ray multilayers optimized for use above 100 keV

DEFF Research Database (Denmark)

Windt, D.L.; Dongey, S.; Hailey, C.J.

2002-01-01

-derived optical constants, which we determined from reflectance-vs-incidence angle measurements also made using synchrotron radiation, in the range E=120 - 180 keV. We describe our experimental investigation in detail, compare the new W/SiC multilayers with both W/Si and W/B4C films that have been studied......We have developed a new depth-graded multilayer system comprising W and SiC layers, suitable for use as hard X-ray reflective coatings operating in the energy range 100 - 200 keV. Grazing incidence X-ray reflectance at E=8 keV was used to characterize the interface widths, as well as the temporal...... and thermal stability in both periodic and depth-graded W/SiC structures, while synchrotron radiation was used to measure the hard X-ray reflectance of a depth-graded multilayer designed specifically for use in the range Esimilar to150 - 170 keV. We have modeled the hard X-ray reflectance using newly...

W/SiC x-ray multilayers optimized for use above 100 keV

DEFF Research Database (Denmark)

Windt, D.L.; Donguy, S.; Hailey, C.J.

2003-01-01

optical constants, which we determined from reflectance versus incidence angle measurements also made using synchrotron radiation, in the range E = 120-180 keV. We describe our experimental investigation in detail, compare the new W/SiC multilayers with both W/Si and W/B4C films that have been studied......We have developed a new depth-graded multilayer system comprising W and SiC layers, suitable for use as hard x-ray reflective coatings operating in the energy range 100-200 keV. Grazing-incidence x-ray reflectance at E = 8 keV was used to characterize the interface widths, as well as the temporal...... and thermal stability in both periodic and depth-graded W/SiC structures, whereas synchrotron radiation was used to measure the hard x-ray reflectance of a depth-graded multilayer designed specifically for use in, the range Esimilar to150-170 keV. We have modeled the hard x-ray reflectance using newly derived...

Calibration of a dePangher long counter from 2 keV to 19 MeV

Energy Technology Data Exchange (ETDEWEB)

Slaughter, D R; Rueppel, D W [California Univ., Livermore (USA). Lawrence Livermore Lab.

1977-09-01

The authors have measured the sensitivity of a dePangher precision long counter (PLC) relative to /sup 7/Li(p,n), T(p,n), and T(d,n) differential cross sections over the neutron energy range 10 keV-19 MeV. Absolute sensitivity at 2 keV is also measured, using a scandium filtered beam at a reactor. Results obtained with errors in the range 5-30% are consistent with the assumption of a nearly constant sensitivity over the range 2 keV-6 MeV, but exhibit a reduction above 12 MeV.

Radiation scattering back to the plasma by the tokamak inner wall in the energy range 50-500 keV during lower hybrid current drive

International Nuclear Information System (INIS)

Peysson, Y.

1990-10-01

We describe the wall reflectivity by the ratio between the number of photons emerging from the wall and the number entering - and determine the proportion of the reflected contribution to the detected radiations. Various emission profiles and plasma positions in the tokamak chamber have been considered. The contribution of multiple reflections has also be investigated. The wall reflectivity can lead to spurious conclusions for a peaked radial profile in the vicinity of the plasma edge. The next step is devoted to the resolution of the radiation transport equation in solid matter. As an heterogeneous medium is considered - carbon tiles brazed on an iron bulk -, the solution is determined by a numerical Monte-Carlo method. The reflectivity is greatly enhanced by a carbon layer between 50 keV and 150 keV, even for a thickness of one centimeter. The reflectivity is then nearly independent of the energy of the entering photons up to 500 KeV, and lies between 0.15 and 0.4 from a perpendicular to a nearly tangential incidence. Angular corrections have also been considered. Finally, a fully description of the X-ray reflectivity in the high energy range has been performed, taking account of the toroidal geometry and the exact solution of the radiation transport equation. Comparison between theoretical and experimental results obtained with the Tore-Supra high energy X-ray spectrometer has been done. A strong reflectivity effect is observed for the more peripheral line of sight when the plasma emission profile is peaked. There is a good agreement for the total number of detected photons with an energy greater than 100 keV The measured energy spectrum lies up to 200 keV when the photon energy spectrum of the plasma determined from the central chords extends up to 500 keV. A procedure to determine the energy threshold above which the photon energy spectrum is free of the reflected contribution is proposed

Optimization of whole-body simulator for photon emitters in the energy range 100 to 3000 KeV

International Nuclear Information System (INIS)

Dantas, Bernardo M.; Rosales, Geovana O.

1996-01-01

The calibration of the detection system for the in vivo determination of uniformly distributed radionuclides emitting photons in the energy range of 100 to 300 KeV requires the use of phantoms with dimensions close to the human body, in which known amounts of radionuclides are added. After the measurement of those phantoms, the calibration curves, channel x energy and energy x efficiency, are constructed. This type of phantom has been continuously optimized at the IRD-CNEN whole body counter with the objective of approximating its characteristics as close as possible to the standard man proposed in the ICRP 23. Furthermore, it has been tried to obtain a safe structure in terms of leakage and also of low cost. (author)

Pu241 cross-sections below 1 keV

International Nuclear Information System (INIS)

Doherty, G.

1966-12-01

Early in 1965 a new data file (DFN 40) for Pu241 covering the energy range 10 - 4 eV to 15 MeV was prepared for the UKAEA Nuclear Data Library. The data above 1 keV are described by Douglas (AWRE 0-101/64) and the data below 1 keV are set out in this report. During the past year a number of additional measurements have been reported for Pu241 and a brief summary of these measurements and their implications for the data on the file are given. (author)

Solar neutrino flux at keV energies

Science.gov (United States)

Vitagliano, Edoardo; Redondo, Javier; Raffelt, Georg

2017-12-01

We calculate the solar neutrino and antineutrino flux in the keV energy range. The dominant thermal source processes are photo production (γ e→ e νbar nu), bremsstrahlung (e+Ze→ Ze+e+νbar nu), plasmon decay (γ→νbar nu), and νbar nu emission in free-bound and bound-bound transitions of partially ionized elements heavier than hydrogen and helium. These latter processes dominate in the energy range of a few keV and thus carry information about the solar metallicity. To calculate their rate we use libraries of monochromatic photon radiative opacities in analogy to a previous calculation of solar axion emission. Our overall flux spectrum and many details differ significantly from previous works. While this low-energy flux is not measurable with present-day technology, it could become a significant background for future direct searches for keV-mass sterile neutrino dark matter.

Linear attenuation coefficients of tissues from 1 keV to 150 keV

Science.gov (United States)

Böke, Aysun

2014-09-01

The linear attenuation coefficients and three interaction processes have been computed for liver, kidney, muscle, fat and for a range of x-ray energies from 1 keV to 150 keV. Molecular photoelectric absorption cross sections were calculated from atomic cross section data. Total coherent (Rayleigh) and incoherent (Compton) scattering cross sections were obtained by numerical integration over combinations of F2m(x) with the Thomson formula and Sm(x) with the Klein-Nishina formula, respectively. For the coherent (Rayleigh) scattering cross section calculations, molecular form factors were obtained from recent experimental data in the literature for values of xelements involved in tissue composition is 5 for liver, 47 for kidney, 44 for muscle and 3 for fat. The results are compared with previously published experimental and theoretical linear attenuation coefficients. In general, good agreement is obtained. The molecular form factors and scattering functions and cross sections are incorporated into a Monte Carlo program. The energy distributions of x-ray photons scattered from tissues have been simulated and the results are presented.

Single-electron capture for 2-8 keV incident energy and direct scattering at 6 keV in He2+-He collisions

International Nuclear Information System (INIS)

Bordenave-Montesquieu, D.; Dagnac, R.

1992-01-01

We studied the single-electron capture as well as the direct processes occurring when a He 2+ ion is scattered by a He target. Doubly differential cross sections were measured for single-electron capture with a collision energy ranging from 2 to 8 keV and a scattering angle varying from 10' to 3 o 30' (laboratory frame). Single-electron capture into excited states of He + was found to be the dominant process, confirming a previous experimental study. Elastic scattering and ionization differential cross sections were measured for E = 6 keV. (Author)

Double excitation of helium in collisions with proton and antiproton impact in the energy range 50-500 keV

International Nuclear Information System (INIS)

Purkait, M.

2009-01-01

Double-electron excitation processes of helium atoms by proton and antiproton impact have been theoretically investigated using the four-body formalism of boundary corrected continuum intermediate state (BCCIS-4B) approximation in the energy range of 50-500 keV. In this formalism, the presence of the projectile in the exit channels is described by distorting the final bound state wave functions with coulomb waves (associated with the projectile-electron interactions). The results are in good agreement with the other theoretical and experimental results. Reasonably better agreements have been found in the intermediate and high energy regions. Contributions to the cross section of the different magnetic sub-shells are also analysed.

Measurement of photon mass attenuation coefficients of plutonium from 60 to 2615 keV

International Nuclear Information System (INIS)

Rettschlag, M.; Berndt, R.; Mortreau, P.

2007-01-01

Measurements have been made to determine plutonium photon mass attenuation coefficients by using a collimated-beam transmission method in the energy range from 60 to 2615 keV. These experimental results were compared with previous experimental and theoretical data. Good agreements are observed in the 240-800 keV energy range, whereas differences up to maximum 10% are observed out of these limits

Calibration efficiency of HPGe detector in the 50-1800 KeV energy range; Calibracao em eficiencia de um detector HPGe na faixa de energias 50 - 1800KeV

Energy Technology Data Exchange (ETDEWEB)

Venturini, Luzia [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Servico de Monitoracao Ambiental

1996-07-01

This paper describes the efficiency of an HPGe detector in the 50 - 1800 keV energy range, for two geometries for water measurements: Marinelli breaker (850 ml) and a polyethylene flask (100 ml). The experimental data were corrected for the summing effect and fitted to a continuous, differentiable and energy dependent function given by 1n({epsilon})=b{sub 0}+b{sub 1}.1n(E/E{sub 0})+ {beta}.1n(E/E{sub 0}){sup 2}, where {beta} = b{sub 2} if E>E{sub 0} and {beta} =a{sub 2} if E {<=}E{sub 0}; {epsilon} = the full absorption peak efficiency; E is the gamma-ray energy and {l_brace}b{sub 0}, b{sub 1}, b{sub 2}, a{sub 2}, E{sub 0} {r_brace} is the parameter set to be fitted. (author)

Attenuation coefficients for fibrous self-compacting concrete in the energy range of 50-3000 keV

Energy Technology Data Exchange (ETDEWEB)

Bento, W.V.; Magalhaes, L.A.M.; Conti, C.C., E-mail: ccconti@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-04-01

The fibrous self-compacting concrete is a high performance concrete with uniformly distributed iron fibers. Transmission measurements, with {sup 137}Cs and {sup 60}Co sources were performed for the attenuation coefficients determination for both ordinary and fibrous self-compacting concretes. The results were compared to each other and to the values found in the literature for ordinary concrete. The mass attenuation coefficient for the fibrous self-compacting concrete showed to be higher than those for ordinary concrete of about 5%, depending on the gamma energy. However, it should be noted that the density of fibrous self-compacting concrete is higher than ordinary concrete, 2.4 g/cm{sup 3} and 1.9 g/cm{sup 3} respectively, increasing still further the difference in mass attenuation coefficient. In addition to that, by using Monte Carlo simulations, with MCNP5 Monte Carlo computer code, the data was extended to the 50-3000 keV gamma energy range. (author)

Attenuation coefficients for fibrous self-compacting concrete in the energy range of 50-3000 keV

International Nuclear Information System (INIS)

Bento, W.V.; Magalhaes, L.A.M.; Conti, C.C.

2017-01-01

The fibrous self-compacting concrete is a high performance concrete with uniformly distributed iron fibers. Transmission measurements, with "1"3"7Cs and "6"0Co sources were performed for the attenuation coefficients determination for both ordinary and fibrous self-compacting concretes. The results were compared to each other and to the values found in the literature for ordinary concrete. The mass attenuation coefficient for the fibrous self-compacting concrete showed to be higher than those for ordinary concrete of about 5%, depending on the gamma energy. However, it should be noted that the density of fibrous self-compacting concrete is higher than ordinary concrete, 2.4 g/cm"3 and 1.9 g/cm"3 respectively, increasing still further the difference in mass attenuation coefficient. In addition to that, by using Monte Carlo simulations, with MCNP5 Monte Carlo computer code, the data was extended to the 50-3000 keV gamma energy range. (author)

Computer simulation of range and damage distributions of 0.5 to 8 keV helium ions in crystalline and amorphous niobium

International Nuclear Information System (INIS)

Maderlechner, G.

1976-03-01

The binary collision cascade simulation program MARLOWE is used to study the influence of the crystal lattice, electronic energy loss and crystal temperature on the range and damage distributions of 0.5 to 8 keV He ions penetrating into a Nb target. If the ions enter the crystal parallel to the close-packed direction, the penetration depth profiles show temperature dependent channeling and dechanneling effects. The range distributions in amorphous Nb agree generally with Lindhard's transport theory if surface effects are taken into account. The damage distributions are nearly independent of the electronic energy loss models. The number of vacancies per incident ion increases linearly with the mean nuclear energy loss of the ion in amorphous as well as in crystalline Nb. (orig./GSCH) [de

Further measurements of K shell photoelectric cross sections for some elements in the range 26<=Z<=41 at 74 keV. [74. 409 keV

Energy Technology Data Exchange (ETDEWEB)

Arora, S K; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Dept. of Physics

1978-12-01

K shell photoelectric cross sections in elements Fe, Ni, Cu, Zn, As, Se, Br, Sr, Zr and Nb have been measured at 74.409 keV. The targets were irradiated with x radiation and gamma radiation beams. In confirmation with the earlier results, the present results also show fairly good agreement with theory.

Radiation blistering of Nb implanted sequentially with helium ions of different energies (3-500 keV)

International Nuclear Information System (INIS)

Guseva, M.I.; Gusev, V.; Krasulin, U.L.; Martinenko, U.V.; Das, S.K.; Kaminsky, M.S.

1976-01-01

Cold rolled, polycrystalline niobium samples were irradiated at room temperature with 4 He + ions sequentially at 14 different energies over an energy range from 3 keV--500 keV in steps of 50 keV. The dose for each energy was chosen to give an approximately uniform concentration of helium between the implant depths corresponding to 3 keV and 500 keV. In one set of experiments the irradiations were started at the Kurchatov Institute with 3 keV 4 He + ions and extended up to 80 keV in several steps. Subsequently, the same target area was irradiated with 4 He + ions at Argonne National Laboratory (ANL) starting at 100 keV and increased to 500 keV in steps of 50 keV. Another set of irradiations were started at ANL with 500 keV 4 He + ions and continued with decreasing ion energies to 100 keV. Subsequently, the same area was irradiated at the Kurchatov Institute starting at 80 keV and continued with decreasing ion energies to 3 keV. Both sets of irradiations were completed for two different total doses, 0.5 C cm -2 and 1.0 C cm -2

Single-electron capture for 2-8 keV incident energy and direct scattering at 6 keV in He[sup 2+]-He collisions

Energy Technology Data Exchange (ETDEWEB)

Bordenave-Montesquieu, D.; Dagnac, R. (Toulouse-3 Univ., 31 (France). Centre de Physique Atomique)

1992-06-14

We studied the single-electron capture as well as the direct processes occurring when a He[sup 2+] ion is scattered by a He target. Doubly differential cross sections were measured for single-electron capture with a collision energy ranging from 2 to 8 keV and a scattering angle varying from 10' to 3[sup o]30' (laboratory frame). Single-electron capture into excited states of He[sup +] was found to be the dominant process, confirming a previous experimental study. Elastic scattering and ionization differential cross sections were measured for E = 6 keV. (Author).

Neutron radiative capture by the 241Am nucleus in the energy range 1 keV-20 MeV

International Nuclear Information System (INIS)

Zolotarev, K.I.; Ignatyuk, A.V.; Tolstikov, V.A.; Tertychnyj, G.Ya.

1998-01-01

Production of high actinides leads to many technological problems in the nuclear power. The 241 Am(n,γ) 242 Am reaction is one of the sources of high actinide buildup. So a knowledge of the radiative capture cross-section of 241 Am for neutron energies up to 20 MeV is of considerable important for present day fission reactors and future advanced reactors. The main goal of this paper is the evaluation of the excitation function for the reaction 241 Am(n,γ) 242 Am in the energy range 1 keV-20 MeV. The evaluation was done on the basis of analysed experimental data, data from theoretical model calculations and systematic predictions for 14.5 MeV and 20 MeV. Data from the present evaluation are compared with the cross-section values given in the evaluations carried out earlier. (author)

Multilayer supermirrors: broadband reflection coatings for the 15- to 100-keV range

DEFF Research Database (Denmark)

Joensen, K. D.; Gorenstein, P.; Christensen, Finn Erland

1994-01-01

reflectivity for X-rays. For hard X-rays (>= 15 keV), the absorption, however, is low enough that it is possible to design supermirrors with 10 - 70% reflectivity in a band approximately equals 3 times the width of the total reflection regime. Supermirrors of W/Si and Ni/C have been successfully fabricated...... and characterized. The measured X-ray reflectivities are well accounted for by the standard dynamical theories of multilayer reflection. Hard X-ray applications that could benefit from X-ray supermirror coatings include focusing and imaging instrumentation for astrophysics, and collimating and focusing device...

A new spectroscopic imager for X-rays from 0.5 keV to 150 keV combining a pnCCD and a columnar CsI(Tl) scintillator

Science.gov (United States)

Schlosser, D. M.; Hartmann, R.; Kalok, D.; Bechteler, A.; Abboud, A.; Shokr, M.; Çonka, T.; Pietsch, U.; Strüder, L.

2017-04-01

By combining a low noise fully depleted pnCCD detector with a columnar CsI(Tl) scintillator an energy dispersive spatial resolving detector can be realized with a high quantum efficiency in the range from below 0.5 keV to above 150 keV. The used scintillator system increases the pulse height of gamma-rays converted in the CsI(Tl), due to focusing properties of the columnar scintillator structure by reducing the event size in indirect detection mode (conversion in the scintillator). In case of direct detection (conversion in the silicon of the pnCCD) the relative energy resolution is 0.7% at 122 keV (FWHM = 850 eV) and the spatial resolution is less than 75 μm. In case of indirect detection the relative energy resolution, integrated over all event sizes is about 9% at 122 keV with an expected spatial precision of below 75 μm.

Test facility for the development of 150-keV, multi-megawatt neutral beam systems

International Nuclear Information System (INIS)

Haughian, W.; Baker, W.R.; Biagi, L.A.; Hopkins, D.B.

1975-11-01

The next generation of CTR experiments, such as the Tokamak Fusion Test Reactor (TFTR), will require neutral-beam injection systems that produce multi-megawatt, 120-keV deuterium-beam pulses of 0.5-second duration. Since present injection systems are operating in the 10- to 40-keV range, an intensive development effort is in progress to meet a 150-keV requirement. The vacuum system and power supplies that make up a test facility to be used in the development of these injectors are described

Cusp shape studies in H+→He collision in the energy range 75-1400 keV: experiment and theory

International Nuclear Information System (INIS)

Zavodszky, P.A.; Gulyas, L.; Sarkadi, L.; Vajnai, T.; Szabo, G.; Ricz, S.; Palinkas, J.; Berenyi, D.

1994-01-01

The aim of the present study was to measure the double differential cross section (DDCS) for the electron ejection as a function of electron energy at 0 observation angle in H + →He collisions. Having in mind that the experimental and theoretical shape parameters of the DDCS known in the literature are rather scattered, we made a systematic study in the projectile energy range 75-1400 keV. The total electron yield and the shape parameters of the DDCS were determined and compared with the corresponding values from 2nd order OBK, CDW and CDW-EIS theories. A further aim of this work was to check whether the velocity of the projectile and that of the electrons at the maximum of the cusp peak are indeed equal. (orig.)

A low background-rate detector for ions in the 5 to 50 keV energy range to be used for radioisotope dating with a small cyclotron

International Nuclear Information System (INIS)

Friedman, P.G.

1986-01-01

Accelerator mass spectrometry in tandem Van de Graaff accelerators has proven successful for radioisotope dating small samples. We are developing a 20 cm diameter 30 to 40 keV cyclotron dedicated to high-sensitivity radioisotope dating, initially for 14 C. At this energy, range and dE/dx methods of particle identification are impossible. Thus arises the difficult problem of reliably detecting 30 to 40 keV 14 C at 10 -2 counts/sec in the high background environment of the cyclotron, where lower energy ions, electrons, and photons bombard the detector at much higher rates. We have developed and tested an inexpensive, generally useful ion detector that allows dark-count rates below 10 -4 counts/sec and excellent background suppression. With the cyclotron tuned near the 13 CH background peak, to the frequency for 14 C, the detector suppresses the background to 6 x 10 -4 counts/sec. For each 14 C ion the detectors grazing-incidence Al 2 O 3 conversion dynode emits about 20 secondary electrons, which are independently multiplied in separate pores of a microchannel plate. The output signal is proportional to the number of secondary electrons, allowing pulse-height discrimination of background. We have successfully tested the detector with positive 12 C, 23 Na, 39 K, 41 K, 85 Rb, 87 Rb, and 133 Cs at 5 to 40 keV, and with 36 keV negative 12 C and 13 CH. It should detect ions and neutrals of all species, at energies above 5 keV, with good efficiency and excellent background discrimination. Counting efficiency and background discrimination improve with higher ion energy. The detector can be operated at least up to 2 x 10 -7 Torr and be repeatedly exposed to air. The maximum rate is 10/sup 6.4/ ions/sec in pulse counting mode and 10/sup 9.7/ ions/sec in current integrating mode

Heliospheric Neutral Atom Spectra Between 0.01 and 6 keV fom IBEX

Science.gov (United States)

Fuselier, S. A.; Allegrini, F.; Bzowski, M.; Funsten, H. O.; Ghielmetti, A. G.; Gloeckler, G.; Heirtzler, D.; Janzen, P.; Kubiak, M.; Kucharek, H.;

Spatial distribution of upstream magnetospheric ≥50 keV ions

Directory of Open Access Journals (Sweden)

G. C. Anagnostopoulos

2000-01-01

Full Text Available We present for the first time a statistical study of \\geq50 keV ion events of a magnetospheric origin upstream from Earth's bow shock. The statistical analysis of the 50-220 keV ion events observed by the IMP-8 spacecraft shows: (1 a dawn-dusk asymmetry in ion distributions, with most events and lower intensities upstream from the quasi-parallel pre-dawn side (4 LT-6 LT of the bow shock, (2 highest ion fluxes upstream from the nose/dusk side of the bow shock under an almost radial interplanetary magnetic field (IMF configuration, and (3 a positive correlation of the ion intensities with the solar wind speed and the index of geomagnetic index Kp, with an average solar wind speed as high as 620 km s-1 and values of the index Kp > 2. The statistical results are consistent with (1 preferential leakage of ~50 keV magnetospheric ions from the dusk magnetopause, (2 nearly scatter free motion of ~50 keV ions within the magnetosheath, and (3 final escape of magnetospheric ions from the quasi-parallel dawn side of the bow shock. An additional statistical analysis of higher energy (290-500 keV upstream ion events also shows a dawn-dusk asymmetry in the occurrence frequency of these events, with the occurrence frequency ranging between ~16%-~34% in the upstream region.Key words. Interplanetary physics (energetic particles; planetary bow shocks

Spatial distribution of upstream magnetospheric ≥50 keV ions

Directory of Open Access Journals (Sweden)

G. Kaliabetsos

Full Text Available We present for the first time a statistical study of geq50 keV ion events of a magnetospheric origin upstream from Earth's bow shock. The statistical analysis of the 50-220 keV ion events observed by the IMP-8 spacecraft shows: (1 a dawn-dusk asymmetry in ion distributions, with most events and lower intensities upstream from the quasi-parallel pre-dawn side (4 LT-6 LT of the bow shock, (2 highest ion fluxes upstream from the nose/dusk side of the bow shock under an almost radial interplanetary magnetic field (IMF configuration, and (3 a positive correlation of the ion intensities with the solar wind speed and the index of geomagnetic index Kp, with an average solar wind speed as high as 620 km s-1 and values of the index Kp > 2. The statistical results are consistent with (1 preferential leakage of ~50 keV magnetospheric ions from the dusk magnetopause, (2 nearly scatter free motion of ~50 keV ions within the magnetosheath, and (3 final escape of magnetospheric ions from the quasi-parallel dawn side of the bow shock. An additional statistical analysis of higher energy (290-500 keV upstream ion events also shows a dawn-dusk asymmetry in the occurrence frequency of these events, with the occurrence frequency ranging between ~16%-~34% in the upstream region.Key words. Interplanetary physics (energetic particles; planetary bow shocks

Characteristics of > 290 keV magnetosheath ions

Directory of Open Access Journals (Sweden)

A. Rigas

Full Text Available We performed a statistical analysis of 290-500 keV ion data obtained by IMP-8 during the years 1982-1988 within the earth's magnetosheath and analysed in detail some time periods withdistinct ion bursts. These studies reveal the following characteristics for magnetosheath 290-500 keV energetic ions: (a the occurrence frequency and the flux of ions increase with increasing geomagnetic activity as indicated by the Kp index; the occurrence frequency was found to be as high as P > 42% for Kp > 2, (b the occurrence frequency in the dusk magnetosheath was found to be slightly dependent on the local time and ranged between ~30% and ~46% for all Kp values; the highest occurrence frequency was detected near the dusk magnetopause (21 LT, (c the high energy ion bursts display a dawn-dusk asymmetry in their maximum fluxes, with higher fluxes appearing in the dusk magnetosheath, and (d the observations in the dusk magnetosheath suggest that there exist intensity gradients of energetic ions from the bow shock toward the magnetopause. The statistical results are consistent with the concept that leakage of magnetospheric ions from the dusk magnetopause is a semi-permanent physical process often providing the magnetosheath with high energy (290-500 keV ions.Key words. Magnetospheric physics (magnetosheath; planetary magnetospheres. Space plasma physics (shock waves.

Contribution to the study of nuclear structure using neutron total cross-section measurements between 400 and 1200 keV: isolated resonances and intermediate structure; Contribution a l'etude de la structure nucleaire par des mesures de sections efficaces neutroniques entre 400 keV et 1200 keV. Resonances isolees et structure intermediaire

Energy Technology Data Exchange (ETDEWEB)

Cabe, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-06-15

The neutron total cross sections have been measured over the energy range 400 keV - 1200 keV for fluorine, aluminium, silicon, phosphorus, vanadium, chromium, manganese, iron, nickel, cobalt and lead with an energy spread of 3 keV. The neutrons were produced by the T (p,n) {sup 3}He reaction, the proton beam was supplied by a 2 MeV Van de Graaff. The structure in {sup 56}Fe has been studied in a more detailed way by measuring six angular distributions in the above range and the elastic scattering excitation curves at four angles. The measurements have made it possible to show the existence of the compound nucleus, as well as the presence of an intermediate structure in certain nuclei. (author) [French] Nous avons mesure les sections efficaces totales neutroniques entre 400 keV et 1200 keV du fluor, de l'aluminium, du silicium, du phosphore, du vanadium, du chrome, du manganese, du fer, du nickel, du cobalt et du plomb avec une dispersion en energie de 3 keV. Les neutrons etaient produits a l'aide de la reaction T (p,n) {sup 3}He, les protons etant acceleres par un Van de Graaff 2 MeV. Nous presentons de plus quatre courbes d'excitation de la diffusion elastique des neutrons sur le fer ainsi que six distributions angulaires. Ces mesures ont permis de mettre en evidence un certain nombres de resonances du noyau compose, ainsi que la presence d'une structure intermediaire dans. certains noyaux. (auteur)

Characterisation of a monolithic active pixel sensor for electron detection in the energy range 10-20 keV

International Nuclear Information System (INIS)

Matheson, J.; Moldovan, G.; Clark, A.; Prydderch, M.; Turchetta, R.; Derbyshire, G.; Kirkland, A.; Allinson, N.

2009-01-01

As part of a feasibility study into the use of novel electron detectors for X-ray photoelectron emission microscopes (XPEEM), we have characterised the imaging performance of a back-illuminated monolithic active pixel sensor (MAPS) operating under both integrating and counting modes for electrons in the energy range 10-20 keV. For integrating mode, we present the detective quantum efficiency (DQE), which shows marked improvements over conventional indirect detectors based on microchannel plates. We also present the modulation transfer function (MTF) and noise power spectrum (NPS), again demonstrating significantly improved performance. For counting mode, we present the quantum efficiency (QE) as a function of incident electron energy. We have evaluated the charge collection efficiency (CCE) and we thereby demonstrate the presence of a ∼200 nm thick dead layer that is linked with reduced CCE at low electron energies. Based on our findings, we believe that the MAPS technology is well matched to future XPEEM instruments using aberration correction.

Measurement of L-shell photoelectric cross sections in high Z elements at 37 and 74 keV

Energy Technology Data Exchange (ETDEWEB)

Allawadhi, K L; Ghumman, B S; Sood, B S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

1977-05-01

L-shell photoelectric cross section measurements have been made at 36.818 and 74.409 keV for four elements in the range 81<=Z<=92. The measurements at 74.409 keV are found to agree with theory, within experimental uncertainties, but the experimental values at 36.818 keV are found to be higher than the theoretical predictions. The possible reasons for the observed discrepancy are discussed.

Charge-transfer cross sections of H+ ions in collisions with noble gas atoms in the energy range below 4.0 keV

International Nuclear Information System (INIS)

Kusakabe, Toshio; Sakaue, Hiroyuki A.; Tawara, Hiroyuki

2011-01-01

Charge-transfer cross sections in collisions of H + ions with the ground state He, Ar, Kr, and Xe atoms have been measured in the energy range below 4.0 keV with the initial growth rate method. These observed cross sections are also compared with previously published experimental data and theoretical predictions. In the He and Ar targets, it is found that some previous experimental data deviate significantly from the present observed cross sections as the collision energy decreases. It has been found that in the Kr and Xe targets, the energy dependence of the present observed cross sections behaves as “near-resonant” charge transfer. (author)

FIRST INTEGRAL OBSERVATIONS OF V404 CYGNI DURING THE 2015 OUTBURST: SPECTRAL BEHAVIOR IN THE 20–650 KeV ENERGY RANGE

Energy Technology Data Exchange (ETDEWEB)

Roques, Jean-Pierre; Jourdain, Elisabeth [Université Toulouse, UPS-OMP, CNRS, IRAP, 9 Av. Roche, BP 44346, F-31028 Toulouse (France); Bazzano, Angela; Fiocchi, Mariateresa; Natalucci, Lorenzo; Ubertini, Pietro [Istituto di Astrofisica e Planetologia Spaziali, INAF, Via Fosso del Cavaliere 100, I-00133 Roma, Italy (Italy)

2015-11-01

In 2015 June, the source V404 Cygni (= GS2023+38) underwent an extraordinary outburst. We present the results obtained during the first revolution dedicated to this target by the INTEGRAL mission and focus on the spectral behavior in the hard X-ray domain, using both SPI and IBIS instruments. The source exhibits extreme variability and reaches fluxes of several tens of Crab. However, the emission between 20 and 650 keV can be understood in terms of two main components, varying on all the observable timescales, similar to what is observed in the persistent black hole system Cyg X-1. The low-energy component (up to ∼200 keV) presents a rather unusual shape, probably due to the intrinsic source variability. Nonetheless, a satisfactory description is obtained with a Comptonization model, if an unusually hot population of seed photons (kT{sub 0} ∼ 7 keV) is introduced. Above this first component, a clear excess extending up to 400–600 keV leads us to investigate a scenario where an additional (cutoff) power law could correspond to the contribution of the jet synchrotron emission, as proposed in Cyg X-1. A search for an annihilation feature did not provide any firm detection, with an upper limit of 2 × 10{sup −4} ph cm{sup −2} s{sup −1} (2σ) for a narrow line centered at 511 keV, on the averaged obtained spectrum.

Measurement of 2-5 keV x-ray emission from laser-target interactions by using fluor-MCP and CsI-XRD detectors

International Nuclear Information System (INIS)

Lee, P.H.Y.; Tirsell, K.G.; Leipelt, G.R.; Laird, W.B.

1981-01-01

For inertial confinement fusion plasma diagnostics, x-ray diode (XRD) detectors using conventional cathodes are not sensitive enough to measure x-rays above approx. 1.5 keV. However, for laser driver fusion targets, x-rays in the range of 2 to 5 keV are important because of their mobility in the target. We have successfully used fluor-microchannel plate (MCP) detectors to obtain absolute x-ray measurements in the 2 to 5 keV range. Recent data obtained from experiments on the Shiva laser system are presented. In addition, designs for a variety of channels in the range using fluor-MCP and CsI-XRD's above 1.5 keV will be discussed

X-ray intensity fluctuation spectroscopy in the energy range from 1 to 4 keV

Energy Technology Data Exchange (ETDEWEB)

Retsch, C.C.

2001-06-01

X-ray intensity fluctuation spectroscopy was developed in the energy range of 1 to 4 keV and was used to study complex sample structures and dynamics in a liquid-crystal - aerosil dispersion. The advantages of a focusing versus a nonfocusing setup were explored, and the effects of using X-ray energies near absorption edges were investigated to enhance the capabilities of the method. It was found that even though excellent real space resolution and an increase in flux density can be gained from a Fresnel zone plate focusing setup, this usually comes at the expense of speckle contrast. At absorption edges, the speckle contrast is dominated by the imaginary part of the sample's index of refraction and therefore varies in a way similar to the total transmitted intensity. Employing these results, the dynamics of a dispersion of low-density silica aerosil in octylcyanobiphenyl (8CB) were studied. It was found that the known cross-over behavior of 8CB - aerosil samples towards the 3d-XY universality class should be understood as the coupling of the aerosil-gel dynamics to the dynamics of the director fluctuations in the liquid-crystal. This work indicates that the aerosil-gel mimics and dampens these director fluctuations and thus, by suppressing the director fluctuations, achieves a pure 3d-XY system. (orig.)

Experimental time resolved measurement of fluence and energy spectra of photons emitted by a pulsed X-ray generator in the range 5-300 keV

International Nuclear Information System (INIS)

Vie, M.; Baboulet, J.P.

1989-01-01

We have developed: - A sensor to measure locally X ray fluence rate amplitude and variation versus time during X ray pulses, - A spectrometer based on ROSS method to measure absolute X ray spectrum versus time during X ray pulses. This metrology is used to characterise single shot X ray pulsed sources emitting photons in the range of 5 to 300 keV. Fluence domain is between 10 -9 and 5 10 -4 J. cm -2 with a few nanoseconds time resolution [fr

Electron bremsstrahlung spectrum, 1--500 keV

International Nuclear Information System (INIS)

Lee, C.M.; Kissel, L.; Pratt, R.H.; Tseng, H.K.

1976-01-01

Numerical data are obtained for the electron bremsstrahlung energy spectrum resulting from incident electrons of kinetic energy 1--500 keV, under the assumption that the process is described as a single-electron transition in a relativistic self-consistent screened potential, using partial-wave expansions. Comparisons with simpler analytical approximations show that these are at best of qualitative validity in this energy range. Our data are used to construct more complete tables of the spectrum by interpolation

Effective atomic numbers for photon energy absorption of essential amino acids in the energy range 1 keV to 20 MeV

International Nuclear Information System (INIS)

Manohara, S.R.; Hanagodimath, S.M.

2007-01-01

Effective atomic numbers for photon energy-absorption (Z PEAeff ) of essential amino acids histidine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine have been calculated by a direct method in the energy region of 1 keV to 20 MeV. The Z PEAeff values have been found to change with energy and composition of the amino acids. The variations of mass energy-absorption coefficient, effective atomic number for photon interaction (Z PIeff ) and Z PEAeff with energy are shown graphically. Significant differences exist between Z PIeff and the Z PEAeff in the energy region of 8-100 keV for histidine and threonine; 6-100 keV for leucine, lysine, tryptophan, phenylalanine and valine; 15-400 keV for methionine. The effect of absorption edge on effective atomic numbers and the possibility of defining two set values of these parameters at the K-absorption edge of high-Z element present in the amino acids are discussed. The reasons for using Z PEAeff rather than the commonly used Z PIeff in medical radiation dosimetry for the calculation of absorbed dose in radiation therapy are also discussed

Synthesis of gold and silver nanoparticles by electron irradiation at 5-15 keV energy

Energy Technology Data Exchange (ETDEWEB)

Mahapatra, S K; Bogle, K A; Dhole, S D; Bhoraskar, V N [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Pune-411007 (India)

2007-04-04

Thin coatings ({approx}10 {mu}m) made from a mixture of polyvinyl alcohol (PVA) and HAuCl{sub 4} or PVA and AgNO{sub 3} on quartz plates were irradiated with 5-15 keV electrons, at room temperature. The electron energy was varied from coating to coating in the range of 5-15 keV, but electron fluence was kept constant at {approx}10{sup 15} e cm{sup -2}. Samples were characterized by the UV-vis, XRD, SEM and TEM techniques. The plasmon absorption peaks at {approx}511 and {approx}442 nm confirmed the formation of gold and silver nanoparticles in the respective electron-irradiated coatings. The XRD, SEM and TEM measurements reveal that the average size of the particles could be tailored in the range of 130-50 nm for gold and from 150-40 nm for silver by varying the electron energy in the range of 5-15 keV. These particles of gold and silver embedded in the polymer could also be separated by dissolving the coatings in distilled water.

Formation of H(2s) atoms by excitation in 10-100 keV H+-H collisions

International Nuclear Information System (INIS)

Higgins, D.P.; Geddes, J.; Gilbody, H.B.

1996-01-01

Cross sections for 2s excitation of H atoms in 10-100 keV H + -H collisions have been determined using a modulated crossed-beam technique. The measurements have been based on observations of the Lyman alpha radiation emitted during electric-field-induced decay of the metastable H(2s) collision products. The results extend the range of the 5-26 keV cross sections measured by Morgan and co-workers to intermediate energies where theoretical predictions based on close-coupling methods are known to be strongly dependent on the choice of the expansion basis. The present cross sections pass through a broad maximum at about 40 keV. Over the range 5-100 keV the available experimental data exhibit an undulatory structure similar to that predicted by some close-coupling calculations but good quantitative agreement is very limited. Close-coupling calculations which employ large basis sets and include a large number of projectile states at the expense of target states are shown to agree less satisfactorily with experiment than those which include only the dominant 1s capture projectile channel. (Author)

Neutron Capture Gamma Ray Cross Sections for Ta, Ag, In and Au between 30 and 175 keV

Energy Technology Data Exchange (ETDEWEB)

Hellstroem, J; Beshai, S

1971-11-15

A new detector has been used to determine neutron capture gamma ray cross sections for Ta, Ag, In and Au. The results are listed and discussed together with associated problems. The energy range from 30 keV to 175 keV is considered

Neutron Capture Gamma Ray Cross Sections for Ta, Ag, In and Au between 30 and 175 keV

International Nuclear Information System (INIS)

Hellstroem, J.; Beshai, S.

1971-11-01

A new detector has been used to determine neutron capture gamma ray cross sections for Ta, Ag, In and Au. The results are listed and discussed together with associated problems. The energy range from 30 keV to 175 keV is considered

Study of Radiation Shielding Properties of selected Tropical Wood Species for X-rays in the 50-150 keV Range

Directory of Open Access Journals (Sweden)

S. Aggrey-Smith

2016-03-01

Full Text Available This paper compares the attenuation coefficients of 20 tropical hard wood species based on their linear and mass attenuation and half value layer (HVL properties for X-rays of energy 50–150 keV using a narrow collimated beam from a Cs-137 source. The narrow collimated beam method made corrections from multiple and small-angle scatterings of photons unnecessary. The attenuation depended on the chemical composition and densities of the wood species. The linear attenuation coefficients of wood species at 50–150 keV were highest for Pterygota macrocarpa (4.53 m−1 and lowest for Antiaris africana (1.24 m−1; the mass attenuation coefficient was highest for Triplochiton scleroxylon (17.62 m2/kg and lowest for Nesogordonia papaverifera (2.27 m2/kg.The HVL was highest for Antiaris africana (0.27 m and lowest for Pterygota macrocarpa (0.149 m. Pterygota macrocarpa of about 0.36 m thickness could serve as a more affordable radiation shielding material against secondary scatter and leakage radiations in place of lead, copper or concrete for low X-ray radiations up to 150 keV.

The 65 keV resonance in the {sup 17}O(p,alpha){sup 14}N thermonuclear reaction

Energy Technology Data Exchange (ETDEWEB)

Sergi, M.L. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Catania (Italy); Spitaleri, C. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Coc, A. [CSNSM, UMR 8609, CNRS/IN2P3and Universite Paris Sud 11, Batiment 104, 91405 Orsay Campus (France); Mukhamedzhanov, A. [Cyclotron Institute, Texas A and M University, College Station, TX 77843 (United States); Burjan, S.V. [Nuclear Physics Institute of ASCR Rez near Prague (Czech Republic); Gulino, M. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Hammache, F. [IPN, IN2P3-CNRS et Universite de Paris-Sud 11, 91406 Orsay Cedex (France); Hons, Z. [Nuclear Physics Institute of ASCR Rez near Prague (Czech Republic); Irgaziev, B. [GIK Institute of Engineering Sciences and Technology Topi District Swabi NWFP (Pakistan); Kiss, G.G. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Kroha, V. [Nuclear Physics Institute of ASCR Rez near Prague (Czech Republic); La Cognata, M. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, Catania (Italy); Lamia, L.; Pizzone, R.G. [Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Universita di Catania, Catania (Italy); Sereville, N. de [IPN, IN2P3-CNRS et Universite de Paris-Sud 11, 91406 Orsay Cedex (France); Somorjai, E. [ATOMKI, Debrecen (Hungary)

2010-03-01

The indirect measurement of {sup 17}O(p,alpha){sup 14}N cross section was performed by means of the Trojan Horse Method. This approach allowed to investigate the ultra-low energy range (E{sub c.m.}=0-300 keV) relevant for several astrophysics environments, where two resonant levels of {sup 18}F at E{sub c.m.}{sup R}=65 keV and E{sub c.m.}{sup R}=183 keV play a significant role in the reaction rate determination.

Neutron-capture cross-section measurement for 163Dy In the neutron energy range from 15 to 75 keV

International Nuclear Information System (INIS)

Kim, Hyun Duk; Jung, Eui Jung; Ahn, Jung Keun; Lee, Dae Won; Kim, Guin Yun; Ro, Tae Ik; Min, Young Ki; Igashira, Masayuki; Ohsaki, Toshiro; Mizuno, Satoshi

2002-01-01

The neutron-capture cross-section of 163 Dy were measured in the neutron energy range from 15 to 75 keV at the 3-MV Pelletron accelerator of the Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology. Pulsed neutrons were produced from the 7 Li(p,n) 7 Be reaction by bombarding a metallic lithium target with the 1.903-MeV proton beam. The incident neutron spectra were measured by means of a neutron time-of-flight method with a 6 Li-glass detector. Capture γ-rays were detected with a large anti-Compton NaI(Tl) spectrometer. A pulse-height weighting technique was applied to the capture γ-ray pulse-height spectra to obtain capture yields. The neutron capture cross-section were determined relative to the standard capture cross-sections of 197 Au. The present results were compared with the previous measurements and the evaluated values of ENDF/B-VI

Neutron capture and fission cross section of Americium-243 in the energy range from 5 to 250 keV

International Nuclear Information System (INIS)

Wisshak, K.; Kaeppeler, F.

1983-04-01

The neutron capture and subthreshold fission cross section of 243 Am was measured in the energy range from 5 to 250 keV using 197 Au and 235 U as the respective standards. Neutrons were produced via the 7 Li(p,n) and the T(p,n) reaction with the Karlsruhe 3-MV pulsed Van de Graaff accelerator. Capture events were detected by two MoxonRae detectors with graphite and bismuthgraphite converters, respectively. Fission events were registered by a NE-213 liquid scintillator with pulse-shape discriminator equipment. Flight paths as short as 50-70 mm were used to obtain optimum signal-to-background ratio. After correction for the different efficiency of the individual converter materials the capture cross section could be determined with a total uncertainty of 3-6%. The respective values for the fission cross section are 8-12%. The results are compared to predictions of recent evaluations, which in some cases are severely discrepant. (orig.)

INTEGRAL observations of the cosmic X-ray background in the 5-100 keV range via occultation by the Earth

DEFF Research Database (Denmark)

Churazov, E.; Sunyaev, R.; Revnivtsev, M.

2007-01-01

by the Earth atmosphere and the Earth auroral emission. Results. The spectrum of the cosmic X-ray background in the energy band 5-100 keV is obtained. The shape of the spectrum is consistent with that obtained previously by the HEAO-1 observatory, while the normalization is similar to 10% higher....... This difference in normalization can ( at least partly) be traced to the different assumptions on the absolute flux from the Crab Nebulae. The increase relative to the earlier adopted value of the absolute flux of the CXB near the energy of maximum luminosity (20-50 keV) has direct implications for the energy...

The Context for IMAP: Voyager and INCA Observations of the Heliosheath at E > 5 keV

Science.gov (United States)

Krimigis, Stamatios M.

2016-04-01

The basic premise of the proposed Interstellar Mapping and Acceleration Probe (IMAP) is detailed scientific understanding of the Heliosheath (HS) and beyond, a region of space explored in situ by Voyager 1 (V1) since 2004, Voyager 2 (V2) since 2007, and remotely via energetic neutral atoms (ENA) by the Cassini/INCA (Ion and Neutral CAmera) since 2003 and IBEX since 2009. The IMAP instrumentation proposed for this purpose combines and extends the IBEX and INCA ENA energy ranges (0.3- 20 keV and 3-200 keV, for low and high energy, respectively). All three missions-Voyagers, Cassini/INCA, and IBEX- have made discovery-class measurements in the HS, the Voyagers providing in situ ion intensities at E > 30 keV, while INCA images ENA in the range 5 INCA ENA allows for the possibility of observing the intensity and time evolution of ions in the HS, thought to give rise to the ENAs via charge-exchange, and the resultant ENA images in the inner heliosphere and their spatial and/or temporal variability. Unfortunately, no such "ground truth" ion measurements are possible at Voyager in the ENA energy range imaged by IBEX. Some of the key findings from the Voyager and Cassini/INCA measurements are as follows: (1) The HS contains a hot plasma population that carries a substantial part (30-50 %) of the total pressure at E > 5 keV, the rest residing below that range, resulting in a beta (particle/magnetic pressure) always > 1, typically >10. (2) The width of the HS in the direction of V1 is ~ 30 AU, but is thought to be larger (40-70 AU) in the southern ecliptic where V2 currently travels.. (3) The ENA intensities at E > 5 keV exhibit a correlation with the solar cycle (SC) over the period 2003 to 2015, with minimum intensities in the anti-nose direction observed ~ 1.5 yrs after solar minimum followed by a recovery thereafter. (4) The in situ ion measurements at V2 within the HS also show a similar SC dependence. The totality of the observations, together with the near

Nucleosynthesis confronts an unstable inert 17 keV state

International Nuclear Information System (INIS)

Enqvist, K.; Kainulainen, K.; Thomson, M.

1991-01-01

We study the cosmological consequences of an inert 17 keV state mixing with the electron neutrino. We find that the nucleosynthesis upper bound on the primordial helium abundance prohibits the existence of such a state, unless its lifetime falls into the range 6x10 -4 s vac -2 s. In this range the decay occurs after the chemical decoupling of the electron neutrinos and before the beginning of the nucleosynthesis, with the result that the predicted helium abundance can be lower than what it would be in the standard scenario. (orig.)

Study on the aligned uranium-235 nuclear decay in the neutron energy range of 1.7 eV - 2.15 keV

International Nuclear Information System (INIS)

Danelyan, L.S.; Zakharov, Yu.V.; Zykov, V.M.; Mostovoj, V.I.; Stolyarov, V.A.; Biryukov, S.A.; Zysina, N.Yu.; Osochnikov, A.A.; Svettsov, A.V.

1983-01-01

Using a time-of-flight neutron spectrometer comparative measurements of intensity of fission reaction on the aligned and non-oriented uranium-235 nuclei have been performed in order to identify the resonances caused by p-neutron capture as well as to determine the p-neutron contribution to the fission cross section in the region of unresolved resonances. In some isolated resonances differences in cross sections on aligned and non-oriented nuclei of about 10% have been observed which can permit to assi.on them to p-resonances. In the region of unresolved resonances in the 0.15-2.15 keV neutron energy range to the accuracy +-1% no changes in the fission cross section during the nuclear alignment have been observ

ORNL 150 keV neutral beam test facility

International Nuclear Information System (INIS)

Gardner, W.L.; Kim, J.; Menon, M.M.; Schilling, G.

1977-01-01

The 150 keV neutral beam test facility provides for the testing and development of neutral beam injectors and beam systems of the class that will be needed for the Tokamak Fusion Test Reactor (TFTR) and The Next Step (TNS). The test facility can simulate a complete beam line injection system and can provide a wide range of experimental operating conditions. Herein is offered a general description of the facility's capabilities and a discussion of present system performance

Study of the double charge-changing collision cross-sections of H+, D+, Li+ ions with organic molecules in the energy range 10-50 keV

International Nuclear Information System (INIS)

Farrokhi, S.

1966-01-01

The variation of the double charge-changing collision cross-sections of H + , D + , Li + ions with organic molecules (CH 4 , C 2 H 6 , C 3 H 8 , C 4 H 10 ) in the energy range 10-50 keV has been studied. Several maximums for σ 1-1 = f(E) have been shown. Their existence should be explained by the different possibilities of dissociating the target-molecules. The position of the maximums, for the H + → H - and D + → D - reactions is in good agreement with that defined by the Massey adiabatic relation. (author) [fr

Calculation of absorption parameters for selected narcotic drugs in the energy range from 1 keV to 100 GeV

Science.gov (United States)

Akman, Ferdi; Kaçal, Mustafa Recep; Akdemir, Fatma; Araz, Aslı; Turhan, Mehmet Fatih; Durak, Rıdvan

2017-04-01

The total mass attenuation coefficients (μ/ρ), total molecular (σt,m), atomic (σt,a) and electronic (σt,e) cross sections, effective atomic numbers (Zeff) and electron density (NE) were computed in the wide energy region from 1 keV to 100 GeV for the selected narcotic drugs such as morphine, heroin, cocaine, ecstasy and cannabis. The changes of μ/ρ, σt,m, σt,a, σt,e, Zeff and NE with photon energy for total photon interaction shows the dominance of different interaction process in different energy regions. The variations of μ/ρ, σt,m, σt,a, σt,e, Zeff and NE depend on the atom number, photon energy and chemical composition of narcotic drugs. Also, these parameters change with number of elements, the range of atomic numbers in narcotic drugs and total molecular weight. These data can be useful in the field of forensic sciences and medical diagnostic.

Recent results for /sup 58/Ni and /sup 56/Fe at ORELA. [Widths, J,. pi. ]. EVEL WIDTHS; LEVEL WIDTHS; PARITY; SPIN; ANGULAR DISTRIBUTION; FAST NEUTRONS; KEV RANGE 100-1000; MEV RANGE 01-10

Energy Technology Data Exchange (ETDEWEB)

Perey, F.G.; Chapman, G.T.; Kinney, W.E.; Perey, C.M.

1977-12-01

Transmission and capture data from /sup 58/Ni were analyzed up to 120 keV and are reported. High-resolution scattering measurements for Fe are discussed, and the determination of the J/sup ..pi../ value for most resonances seen in transmission data up to 400 keV is given, including an attempt at evaluation of the resonances of /sup 56/Fe on the basis of recently published data. 4 figures, 3 tables.

Sputtering of thin and intermediately thick films of solid deuterium by keV electrons

DEFF Research Database (Denmark)

Svendsen, Winnie Edith; Thestrup Nielsen, Birgitte; Schou, Jørgen

1995-01-01

Sputtering of films of solid deuterium by keV electrons was studied in a cryogenic set-up. The sputtering yield shows a minimum yield of about 4 D2/electron for 1.5 and 2 keV electrons at a thickness slightly larger than the average projected range of the electrons. We suggest that the yield around...... the minimum represents the value closest to a bulk-yield induced by electron bombardment. It may also include contributions from the mechanisms that enhance the yield for thin and very thick films....

Studies on keV and eV electrons in solids

International Nuclear Information System (INIS)

Schou, J.

1979-10-01

The interaction between keV or eV electrons and solids was studied. The results presented mostly concern problems in connection with electron irradiation of solids, but to some extent they also include ion-induced secondary electron emission. The experiments were mainly performed on solidified gases using 1 - 3 keV electrons. The projected range of electrons was determined in solid hydrogen, deuterium and nitrogen. The true secondary electron emission coefficient and the electron reflection coefficient of solid hydrogen, deuterium and nitrogen were measured. The escape depth of the true secondary electrons in nitrogen was determined. The angular dependence of both the reflection coefficient and the true secondary electron emission coefficient of solid hydrogen and deuterium was investigated. Both ion- and electron-induced secondary electron emission were treated theoretically on the basis of ionization cascade theory. (Auth.)

Calibration of hard x-ray (15 - 50 keV) optics at the MPE test facility PANTER

Science.gov (United States)

Bräuninger, Heinrich; Burkert, Wolfgang; Hartner, Gisela D.; Citterio, Oberto; Ghigo, Mauro; Mazzoleni, Francesco; Pareschi, Giovanni; Spiga, Daniele

2004-02-01

The Max-Planck-Institut für extraterrestrische Physik (MPE) in Garching, Germany, operates the large X-ray beam line facility PANTER for testing astronomical systems. At PANTER a number of telescopes like EXOSAT, ROSAT, SAX, JET-X, ABRIXAS, XMM and SWIFT operating in the soft energy range (0.02 - 15 keV) have been successfully calibrated. In the present paper we report on an important upgrade recently implemented that enables the calibration of hard X-ray optics (from 15 up to 50 keV). Currently hard X-ray optics based on single and multilayer coating are being developed for several future X-ray missions. The hard X-ray calibrations at PANTER are carried out by a high energy source based on an electron gun and several anodes, able to cover the energy range from 4.5 up to 50 keV. It provides fluxes up to 104 counts/sec/cm2 at the instrument chamber with a stability better than 1%. As detector a pn-CCD camera operating between 0.2 and 50 keV and a collecting area of 36 cm2 is used. Taking into account the high energy resolution of the CCD (145 eV at 6 keV), a very easy way to operate the facility in hard X-ray is in energy-dispersive mode (i.e. with a broad-band beam). A double crystal monochromator is also available providing energies up to 20 keV. In this paper we present the first results obtained by using PANTER for hard X-ray characterizations, performed on prototype multilayer optics developed by the Osservatorio Astronomico di Brera (OAB), Milano, Italy, and the Harvard-Smithsonian Center for Astrophysics (CfA), Cambridge, MA, USA.

A New Observation of the Quiet Sun Soft X-ray (0.5-5 keV) Spectrum

Science.gov (United States)

Caspi, Amir; Woods, Thomas N.; Stone, Jordan

2013-03-01

The solar corona is the brightest source of X-rays in the solar system, and the X-ray emission is highly variable with solar activity. While this is particularly true during solar flares, when emission can be enhanced by many orders of magnitude up to gamma-ray energies, even the so-called "quiet Sun" is bright in soft X-rays (SXRs), as the 1-2 MK ambient plasma of the corona emits significant thermal bremsstrahlung up to 5 keV. However, the actual solar SXR (0.5-5 keV) spectrum is not well known, particularly during quiet periods, as, with few exceptions, this energy range has not been systematically studied in many years. Previous observations include ultra-high-resolution but very narrow-band spectra from crystral spectrometers (e.g. Yohkoh/BCS), or integrated broadband irradiances from photometers (e.g. GOES/XRS, TIMED/XPS, etc.) that lack detailed spectral information. In recent years, broadband measurements with fair energy resolution ( 0.5-0.7 keV FWHM) were made by SphinX on CORONAS-Photon and XRS on MESSENGER, although they did not extend below 1 keV. We present observations of the quiet Sun SXR emission obtained using a new SXR spectrometer flown on the third SDO/EVE underflight calibration rocket (NASA 36.286). The commercial off-the-shelf Amptek X123 silicon drift detector, with an 8-micron Be window and custom aperture, measured the solar SXR emission from 0.5 to >10 keV with 0.15 keV FWHM resolution (though, due to hardware limitations, with only 0.12 keV binning) and 2-sec cadence over 5 minutes on 23 June 2012. Despite the rising solar cycle, activity on 23 June 2012 was abnormally low, with no visible active regions and GOES XRS emission near 2010 levels; we measured no solar counts above 4 keV during the observation period. We compare our X123 measurements with spectra and broadband irradiances from other instruments, including the SphinX observations during the deep solar minimum of 2009, and with upper limits of >3 keV quiet Sun emission

Contribution to time resolved X-ray fluence and differential spectra measurement method improvement in 5-200 KeV range. Application to pulsed emission sources

International Nuclear Information System (INIS)

Vie, M.

1983-09-01

Two types of sensors have been developed to measure locally the time-resolved fluence and differential energetic spectrum of pulsed X-ray in the energy range 5 to 200 keV. Rise time of these sensors is very short (10 ns) in order to permit time-resolved measurements. Fluence sensors have been developed by putting filters in front of detector in order to make sensor response independent of X-ray energy and proportional to X-ray fluence. The energetic differential spectrum was calculated by way of a method similar to the ROSS method but using filters separated within a pair defining adjacent spectral width. A detailed analysis of uncertainties affecting calculated fluence and spectrum has been done [fr

Comparison of measured and calculated 238U capture self-indication ratios from 4 to 10 keV

International Nuclear Information System (INIS)

Perez, R.B.; de Saussure, G.; Yang, J.T.; Munoz-Cobos, J.L.; Todd, J.H.

1983-01-01

From 4 keV to 149 keV the 238 U cross sections are represented in ENDF/B-V by unresolved-resonance parameters (URP). The purpose of this representation is to enable the calculation of resonance self-protection as a function of temperature and dilution. Since the URPs are not defined unambiguously by the cross-section data, it is important that the unresolved representation be tested with appropriate experiments, such as capture self-indication ratio (SIR) measurements. In this paper we compare 238 U capture SIR measurements in the 4- to 10-keV energy range with calculations done with ENDF/B-V and with recently published resolved resonance parameters

High accuracy experimental determination of copper and zinc mass attenuation coefficients in the 100 eV to 30 keV photon energy range

Science.gov (United States)

Ménesguen, Y.; Gerlach, M.; Pollakowski, B.; Unterumsberger, R.; Haschke, M.; Beckhoff, B.; Lépy, M.-C.

2016-02-01

The knowledge of atomic fundamental parameters such as mass attenuation coefficients with low uncertainties, is of decisive importance in elemental quantification using x-ray fluorescence analysis techniques. Several databases are accessible and frequently used within a large community of users. These compilations are most often in good agreement for photon energies in the hard x-ray ranges. However, they significantly differ for low photon energies and around the absorption edges of any element. In a joint cooperation of the metrology institutes of France and Germany, mass attenuation coefficients of copper and zinc were determined experimentally in the photon energy range from 100 eV to 30 keV by independent approaches using monochromatized synchrotron radiation at SOLEIL (France) and BESSY II (Germany), respectively. The application of high-accuracy experimental techniques resulted in mass attenuation coefficient datasets determined with low uncertainties that are directly compared to existing databases. The novel datasets are expected to enhance the reliability of mass attenuation coefficients.

Identification of an isomer in 110Ag at 1-keV excitation energy

International Nuclear Information System (INIS)

Clark, D.D.; Kostroun, V.O.; Siems, N.E.

1975-01-01

The existence of a new isomeric state in 110 Ag at approx. 1 keV excitation has been established in two experiments using a new instrument, the inner-shell-vacancy (ISV) detector. In the first experiment, a transition with a half-life of 660 plus-or-minus 40 ns was observed to follow the well-known 116-keV M4 transition that depopulates the 6 + 250-day isomeric level in 110 Ag; the energy of the new transition was deduced to be 109 Ag(n, γ) 110 Ag reaction to follow γ transitions previously assigned by others to populate a 1-keV excited state. The two results indicate the existence of a 2 - 660-ns isomer at 1.11 keV. Under the assumption that the newly observed transition is from a 2 - 1.11-keV state to the 1 + ground state, its hindrance factor with respect to the Moszkowski estimate is approx. 2.6 times 10 3 . Possible chemical-state perturbations of the measured half-life are estimated to be much smaller than the measurement error. In both experiments the approx. 1-keV transition was detected with the ISV detector, a new device based on the well-established atomic effect that within approx. 10 -14 s after the formation of an inner shell vacancy an atom will undergo a multiple loss of []lectrons ranging from several to 20 or more, the number being a function of Z and subshell. The emitted electrons, which are very soft, are collected with an accelerating and focusing electrostatic lens and detected with a plastic scintillator and a photomultiplier tube. Nuclear transitions that cause ISVs can thus be sensed. Experiments are described that show the detector is fast, sensitive, selective, and efficient in responding to ISVs.

Steady State Sputtering Yields and Surface Compositions of Depleted Uranium and Uranium Carbide bombarded by 30 keV Gallium or 16 keV Cesium Ions.

Energy Technology Data Exchange (ETDEWEB)

Siekhaus, W. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Teslich, N. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Weber, P. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2014-10-23

Depleted uranium that included carbide inclusions was sputtered with 30-keV gallium ions or 16-kev cesium ions to depths much greater than the ions’ range, i.e. using steady-state sputtering. The recession of both the uranium’s and uranium carbide’s surfaces and the ion corresponding fluences were used to determine the steady-state target sputtering yields of both uranium and uranium carbide, i.e. 6.3 atoms of uranium and 2.4 units of uranium carbide eroded per gallium ion, and 9.9 uranium atoms and 3.65 units of uranium carbide eroded by cesium ions. The steady state surface composition resulting from the simultaneous gallium or cesium implantation and sputter-erosion of uranium and uranium carbide were calculated to be U₈₆Ga₁₄, (UC)₇₀Ga₃₀ and U₈₁Cs₉, (UC)₇₉Cs₂₁, respectively.

Angular distribution of thick-target bremsstrahlung produced by electrons with initial energies ranging from 10 to 20 keV incident on Ag

Energy Technology Data Exchange (ETDEWEB)

Gonzales, D.; Cavness, B.; Williams, S. [Department of Physics, Angelo State University, San Angelo, Texas 76909 (United States)

2011-11-15

Experimental results are presented comparing the intensities of the bremsstrahlung produced by electrons with initial energies ranging from 10 to 20 keV incident on a thick Ag target, measured at forward angles in the range of 0 degree sign to 55 degree sign . When the data are corrected for attenuation due to photon absorption within the target, the results indicate that the detected radiation is distributed anisotropically only at photon energies k that are approximately equal to the initial energy of the incident electrons E{sub 0}. The results of our experiments suggest that, as k/E{sub 0}{yields} 0, the detected radiation essentially becomes isotropic due primarily to the scattering of electrons within the target. A comparison to the theory of Kissel et al.[At. Data Nucl. Data Tables 28, 381 (1983)] suggests that the angular distribution of bremsstrahlung emitted by electrons incident on thick targets is similar to the angular distribution of bremsstrahlung emitted by electrons incident on free-atom targets only when k/E{sub 0}{approx_equal} 1. The experimental data also are in approximate agreement with the angular distribution predictions of the Monte Carlo program penelope.

Measurement of high-energy (10–60 keV) x-ray spectral line widths with eV accuracy

Energy Technology Data Exchange (ETDEWEB)

Seely, J. F., E-mail: seelyjf@gmail.com; Feldman, U. [Artep Inc., 2922 Excelsior Springs Court, Ellicott City, Maryland 21042 (United States); Glover, J. L.; Hudson, L. T.; Ralchenko, Y.; Henins, Albert [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Pereira, N. [Ecopulse Inc., P. O. Box 528, Springfield, Virginia 22152 (United States); Di Stefano, C. A.; Kuranz, C. C.; Drake, R. P. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Chen, Hui; Williams, G. J.; Park, J. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

2014-11-15

A high resolution crystal spectrometer utilizing a crystal in transmission geometry has been developed and experimentally optimized to measure the widths of emission lines in the 10–60 keV energy range with eV accuracy. The spectrometer achieves high spectral resolution by utilizing crystal planes with small lattice spacings (down to 2d = 0.099 nm), a large crystal bending radius and Rowland circle diameter (965 mm), and an image plate detector with high spatial resolution (60 μm in the case of the Fuji TR image plate). High resolution W L-shell and K-shell laboratory test spectra in the 10–60 keV range and Ho K-shell spectra near 47 keV recorded at the LLNL Titan laser facility are presented. The Ho K-shell spectra are the highest resolution hard x-ray spectra recorded from a solid target irradiated by a high-intensity laser.

Biophysical interpretation of the response of Chinese hamster cells to 24 keV neutrons

International Nuclear Information System (INIS)

Holt, P.D.

1988-01-01

The response of V79 Chinese hamster cells to a 24 keV neutron spectrum has been compared with data for the response of V79 cells to a range of higher neutron energies (up to 15 MeV). The linear energy transfer (LET) distributions of the neutron spectra were calculated and the expected responses of the cells to the different spectra were calculated using published track-segment data on the response of V79 cells to charged particles with various LET values. The response of the cells to 24 keV neutrons was predicted satisfactorily by the LET distribution, in spite of the fact that the maximum range of the recoil protons is only 0.5 μm. The response was not correctly predicted by the microdosimetric parameter y-bar D * evaluated in a 1 μm diameter sphere. (author)

The ASDEX 100 keV neutral lithium beam diagnostic gun

International Nuclear Information System (INIS)

McCormick, K.; Kick, M.

1983-04-01

The neutral lithium beam gun intended for measurement of the poloidal magnetic field and of the density gradient in the scrape-off layer of ASDEX is described, and test results over a beam energy range of 27-100 keV are presented. In the gun, lithium ions are extracted from a solid emitter (#betta#-Eurcryptite) in a Pierce-type configuration, accelerated and focused in a two-tube immersion lens, and neutralized in a charge-exchange cell using sodium. The beam can be pulsed from less than one to several seconds, depending on experimental needs. At a distance of 165 cm from the gun the neutral beam equivalent current is typically greater than 1 mA (0.16 mA) for a beam energy of 100 keV (27 keV), the beam FWHM being about 8-9 mm. It is found that to produce a particular beam with a certain ratio must be maintained between the extraction and total beam voltages, this relationship depending in turn on the emitter-extractor separation. The principal features which distinguish the ASDEX gun from that employed on W7a are the greater compactness - all the active elements, i.e. emitter, extractor, lens, deflection plates and neutralizer, are contained with 57 cm - and the vacuum vessel, which simultaneously serves as the magnetic shielding. (orig.)

Studies on the bombardment of condensed molecular gases at liquid-He temperatures by keV electrons and light ions

International Nuclear Information System (INIS)

Boergesen, P.

1982-09-01

Films of solid H 2 , D 2 and N 2 were irradiated with keV electrons and ions. Stopping cross sections and ranges of 0.3-10 keV/amu light ions in solid H 2 and D 2 are in good agreement with experimental and theoretical data on gaseous targets. In contrast, both stopping cross section and range measurements in solid N 2 suggest that the stopping here is only about half of that in N 2 -gas. This ''phase-effect'' is further supported by secondary emission measurements. Secondary electron emission coefficients for 2-10 keV H 1 + , H 2 + , H 3 + , D 3 + , D 2 H + , 4 He + , 14 N + and 20 Ne + incident on solids H 2 , D 2 and N 2 are in reasonable agreement with previous results for electron-incidence. The rather large erosion yields for 1-3 keV electrons incident on solid D 2 depend strongly on target thickness (for thin films), but weakly on energy. Bulk yields for 2 keV electrons were approximately 8 H 2 /electron, approximately 4 D 2 /electron and approximately 0.5 N 2 /electron. Secondary ion emission during ion bombardment seems to be predominantly reflected projectiles in the case of N 2 -targets, while it may be explained as sputtered particles from H 2 - and D 2 -targets. Preliminary results on the erosion of solid H 2 and D 2 by keV light ions indicate very large erosion yields (approx. 400 H 2 /atom for 2 keV protons) increasing strongly with energy. (Auth.)

A 20 keV electron gun system for the electron irradiation experiments

International Nuclear Information System (INIS)

Mahapatra, S.K.; Dhole, S.D.; Bhoraskar, V.N.

2005-01-01

An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 μA. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure ∼10 -7 mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours

A 20 keV electron gun system for the electron irradiation experiments

Energy Technology Data Exchange (ETDEWEB)

Mahapatra, S.K. [Department of Physics, University of Pune, Pune 411007 (India); Dhole, S.D. [Department of Physics, University of Pune, Pune 411007 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411007 (India)]. E-mail: vnb@physics.unipune.ernet.in

2005-01-01

An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 {mu}A. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure {approx}10{sup -7} mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours.

DISPLACEMENT CASCADE SIMULATION IN TUNGSTEN UP TO 200 KEV OF DAMAGE ENERGY AT 300, 1025, AND 2050 K

Energy Technology Data Exchange (ETDEWEB)

Setyawan, Wahyu; Nandipati, Giridhar; Roche, Kenneth J.; Kurtz, Richard J.; Wirth, Brian D.

2015-09-22

We generated molecular dynamics database of primary defects that adequately covers the range of tungsten recoil energy imparted by 14-MeV neutrons. During this semi annual period, cascades at 150 and 200 keV at 300 and 1025 K were simulated. Overall, we included damage energy up to 200 keV at 300 and 1025 K, and up to 100 keV at 2050 K. We report the number of surviving Frenkel pairs (NF) and the size distribution of defect clusters. The slope of the NF curve versus cascade damage energy (EMD), on a log-log scale, changes at a transition energy (μ). For EMD > μ, the cascade forms interconnected damage regions that facilitate the formation of large clusters of defects. At 300 K and EMD = 200 keV, the largest size of interstitial cluster and vacancy cluster is 266 and 335, respectively. Similarly, at 1025 K and EMD = 200 keV, the largest size of interstitial cluster and vacancy cluster is 296 and 338, respectively. At 2050 K, large interstitial clusters also routinely form, but practically no large vacancy clusters do

On the 17-keV neutrino

International Nuclear Information System (INIS)

Hime, A.

1993-04-01

A brief review on the status of the 17-keV neutrino is presented. Several different experiments found spectral distortions which were consistently interpreted as evidence for a heavy neutrino admixture in β decay. Recent experiments, however, rule out the existence of a 17-keV neutrino as well as escaping criticisms of earlier null results. Moreover, the majority of positive results have been reinterpreted in terms of instrumental effects, despite the need for a different explanation in each case. Anomalies persist in the low energy region of the tritium spectrum which deserve further investigation

Cross section for induced L X-ray emission by protons of energy <400 keV

International Nuclear Information System (INIS)

Mohan, Harsh; Jain, Arvind Kumar; Kaur, Mandeep; Singh, Parjit S.; Sharma, Sunita

2014-01-01

In performing ion beam analysis, cross section for induced L X-ray emission plays a crucial role. There are different approaches by which these can be found experimentally or can be calculated theoretically based on various models. L X-ray production cross sections for Bi with protons in the energy range 260–400 keV at the interval of 20 keV are measured. These are compared with calculations obtained on the basis of current prevailing theories ECPSSR and ECPSSR-UA. Their importance in understanding this phenomenon and existing arguments in this regard will be highlighted

Measurement of the x-ray mass-attenuation coefficients of gold, derived quantities between 14 keV and 21 keV and determination of the bond lengths of gold

International Nuclear Information System (INIS)

Glover, J L; Chantler, C T; Barnea, Z; Rae, N A; Tran, C Q

2010-01-01

The x-ray mass-attenuation coefficients of gold are measured at 91 energies between 14 keV and 21 keV using synchrotron radiation. The measurements are accurate to between 0.08% and 0.1%. The photoelectric mass-absorption coefficients and the imaginary component of the form factors of gold are also determined. The results include the L I edge and are the most accurate and extensive gold dataset available in this energy range. An analysis of the L I edge XAFS showed excellent agreement between the measured and simulated XAFS and yielded highly accurate values of the bond lengths of gold. When our results are compared with earlier measurements and with predictions of major theoretical tabulations, significant discrepancies are noted. The comparison raises questions about the nature of discrepancies between experimental and theoretical values of mass-attenuation coefficients.

Studies on effective atomic numbers for photon energy absorption and electron density of some narcotic drugs in the energy range 1 keV-20 MeV

Science.gov (United States)

Gounhalli, Shivraj G.; Shantappa, Anil; Hanagodimath, S. M.

2013-04-01

Effective atomic numbers for photon energy absorption ZPEA,eff, photon interaction ZPI,eff and for electron density Nel, have been calculated by a direct method in the photon-energy region from 1 keV to 20 MeV for narcotic drugs, such as Heroin (H), Cocaine (CO), Caffeine (CA), Tetrahydrocannabinol (THC), Cannabinol (CBD), Tetrahydrocannabivarin (THCV). The ZPEA,eff, ZPI,eff and Nel values have been found to change with energy and composition of the narcotic drugs. The energy dependence ZPEA,eff, ZPI,eff and Nel is shown graphically. The maximum difference between the values of ZPEA,eff, and ZPI,eff occurs at 30 keV and the significant difference of 2 to 33% for the energy region 5-100 keV for all drugs. The reason for these differences is discussed.

An analytical expression for electron elastic scattering cross section from atoms and molecules in 1.0 keV to 1.0 MeV energy range

Energy Technology Data Exchange (ETDEWEB)

Yalcin, S. [Education Faculty, Kastamonu University, 37200 Kastamonu (Turkey)]. E-mail: yalcin@gazi.edu.tr; Gurler, O. [Physics Department, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey); Gultekin, A. [Physics Department, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey); Gundogdu, O. [School of Engineering, University of Surrey, Guildford, GU2 7XH (United Kingdom)]. E-mail: o.gundogdu@surrey.ac.uk

2006-07-31

In this Letter, an expression is presented to calculate elastic scattering cross sections for incident electrons as a function of both energy and atomic number in the energy range between 1 keV and 1 MeV for materials with effective atomic number between 3 and 18. The expression we present has a rather simple analytical form which gives accurate results that are in very good agreement with the results calculated by a relativistic partial-wave expansion method. Hence, this equation can be employed accurately and efficiently in a continuous manner, without the need to go through rather large look-up tables, thus making the whole process quick, efficient and removing possible computational errors that may arise from the efforts of interpolation.

An analytical expression for electron elastic scattering cross section from atoms and molecules in 1.0 keV to 1.0 MeV energy range

International Nuclear Information System (INIS)

Yalcin, S.; Gurler, O.; Gultekin, A.; Gundogdu, O.

2006-01-01

In this Letter, an expression is presented to calculate elastic scattering cross sections for incident electrons as a function of both energy and atomic number in the energy range between 1 keV and 1 MeV for materials with effective atomic number between 3 and 18. The expression we present has a rather simple analytical form which gives accurate results that are in very good agreement with the results calculated by a relativistic partial-wave expansion method. Hence, this equation can be employed accurately and efficiently in a continuous manner, without the need to go through rather large look-up tables, thus making the whole process quick, efficient and removing possible computational errors that may arise from the efforts of interpolation

Neutron cross section evaluations of europium isotopes in 1 keV - 30 MeV energy range. Format - validation - comparison; Evaluation de sections efficaces pour des neutrons incidents sur des isotopes d'europium aux energies 1 keV - 30 MeV. Format - validation - comparaison

Energy Technology Data Exchange (ETDEWEB)

Dossantos-Uzarralde, P.; Le Luel, C.; Bauge, E. [CEA Bruyeres le Chatel, 91 (France). Dept. de Physique Theorique et Appliquee

2004-07-01

This paper presents neutron cross section evaluations of Europium isotopes. The cross sections are evaluated in 1 keV - 30 MeV energy range for the isotopes {sup 146}Eu, {sup 147}Eu, {sup 148}Eu, {sup 149}Eu, {sup 150}Eu, {sup 151}Eu, {sup 152}Eu, {sup 153}Eu, {sup 154}Eu in their ground state. This evaluation includes cross section productions of the long life isomeric states. Special attention is put on the options used for the description of the files written in ENDF-6 format. The final issue is a proposal of a new breed of ENDF-6 formatted neutron activation file. (authors)

High accuracy measurement of the $^{235}$U(n,f) reaction cross-section in the 10-30 keV neutron energy range

CERN Multimedia

The analysis of the neutron flux of n_TOF (in EAR1) revealed an anomaly in the 10-30 keV neutron energy range. While the flux extracted on the basis of the $^{6}$Li(n,t)$^{4}$He and $^{10}$B(n,$\\alpha$)$^{7}$Li reactions mostly agreed with each other and with the results of FLUKA simulations of the neutron beam, the one based on the $^{235}$U(n,f) reaction was found to be systematically lower, independently of the detection system used. A possible explanation is that the $^{235}$U(n,f) crosssection in that energy region, where in principle should be known with an uncertainty of 1%, may be systematically overestimated. Such a finding, which has a negligible influence on thermal reactors, would be important for future fast critical or subcritical reactors. Furthermore, its interest is more general, since the $^{235}$U(n,f) reaction is often used at that energy to determine the neutron flux, or as reference in measurements of fission cross section of other actinides. We propose to perform a high-accuracy, high-r...

Development of 350 keV electron accelerator

International Nuclear Information System (INIS)

Qin Jiuchang; Cui Shan; Zhou Wenzhen; Cui Zhipeng; Shi Zhenghu; Lu Zhongcheng; Chen Shangwen; Zhang Lifeng; Cui Zongwei; Huang Jun; Yin Meng

2007-01-01

The 350 keV electron accelerator is used for irradiation and production of plas- tic film of the medical infusion bags. The body structure of Van de Graft accelerator and the high voltage power supply of Cockcrof-Walton accelerator are adopted in the electron accelerator. The 350 keV DC power supply is supplied by the high frequency power supply with 14 kHz and 35 kW. The body and DC power supply of the electron accelerator are installed in the tank filled with 0.3 MPa SF 6 . The electron accelerator is compact, self-shielding and suitable for on-line electron beam processing. The main characteristics of the facility are terminal voltage 370 kV, electron beam power 7 kW (350 keV/20 mA), scaning width 70 cm, irradiation dose inuniformity ≤7%. (authors)

40 keV atomic resolution TEM

International Nuclear Information System (INIS)

Bell, David C.; Russo, Christopher J.; Kolmykov, Dmitry V.

2012-01-01

Here we present the first atomic resolution TEM imaging at 40 keV using an aberration-corrected, monochromated source TEM. Low-voltage High-Resolution Electron Microscopy (LVHREM) has several advantages, including increased cross-sections for inelastic and elastic scattering, increased contrast per electron and improved spectroscopy efficiency, decreased delocalization effects and reduced knock-on damage. Together, these often improve the contrast to damage ratio obtained on a large class of samples. Third-order aberration correction now allows us to operate the TEM at low energies while retaining atomic resolution, which was previously impossible. At low voltage the major limitation to resolution becomes the chromatic aberration limit. We show that using a source monochromator we are able to reduce the effect of chromatic aberration and achieve a usable high-resolution limit at 40 keV to less than 1 Å. We show various materials' examples of the application of the technique to image graphene and silicon, and compare atomic resolution images with electron multislice simulations. -- Highlights: ► We present the first atomic resolution images recorded at 40 keV using an aberration-corrected, monochromated TEM. ► We show information transfer measured to better than 1 Å. ► At 40 keV an aberration-corrected monochromated TEM is limited by fifth-order spherical aberration. ► We show that using a monochromator the effect of chromatic aberration is reduced to enable high resolution imaging. ► Low voltage high resolution electron microscopy will be beneficial for imaging the organic/inorganic materials interface.

Beta decay anomalies and the 17-keV conundrum

International Nuclear Information System (INIS)

Hime, A.

1993-01-01

Recent developments in pursuance of the 17-keV neutrino are reviewed. Several different experiments found anomalies in β decay spectra which were consistently interpreted as evidence for a heavy neutrino. On the other hand, recent null results definitively rule out the existence of a 17-keV neutrino, as well as escaping criticisms applicable to earlier experiments. While missing links remain, it seems that any strong evidence for a 17-keV neutrino has vanished. Specifically, the anomalies observed in 35 S and 63 Ni spectra at Oxford can be reinterpreted in terms of electron scattering effects. In addition, the discrepancy amongst internal bremsstrahlung measurements has an instrumental origin, and recent results disfavour a 17-keV neutrino. Anomalies persist in the low energy region of the tritium spectrum which deserve further investigation

Carotid dual-energy CT angiography: Evaluation of low keV calculated monoenergetic datasets by means of a frequency-split approach for noise reduction at low keV levels.

Science.gov (United States)

Riffel, Philipp; Haubenreisser, Holger; Meyer, Mathias; Sudarski, Sonja; Morelli, John N; Schmidt, Bernhard; Schoenberg, Stefan O; Henzler, Thomas

2016-04-01

Calculated monoenergetic ultra-low keV datasets did not lead to improved contrast-to-noise ratio (CNR) due to the dramatic increase in image noise. The aim of the present study was to evaluate the objective image quality of ultra-low keV monoenergetic images (MEIs) calculated from carotid DECT angiography data with a new monoenergetic imaging algorithm using a frequency-split technique. 20 patients (12 male; mean age 53±17 years) were retrospectively analyzed. MEIs from 40 to 120 keV were reconstructed using the monoenergetic split frequency approach (MFSA). Additionally MEIs were reconstructed for 40 and 50 keV using a conventional monoenergetic (CM) software application. Signal intensity, noise, signal-to-noise ratio (SNR) and CNR were assessed in the basilar, common, internal carotid arteries. Ultra-low keV MEIs at 40 keV and 50 keV demonstrated highest vessel attenuation, significantly greater than those of the polyenergetic images (PEI) (all p-values 0.05). Thus MEIs with MFSA showed significantly higher SNR and CNR compared to MEIs with CM. Combining the lower spatial frequency stack for contrast at low keV levels with the high spatial frequency stack for noise at high keV levels (frequency-split technique) leads to improved image quality of ultra-low keV monoenergetic DECT datasets when compared to previous monoenergetic reconstruction techniques without the frequency-split technique. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Evidence of a cyclotron line at 70 keV from 4U0531 + 21

International Nuclear Information System (INIS)

Polcaro, V.F.; Bazzano, A.; La Padula, C.D.; Ubertini, P.

1981-01-01

The HXR79 hard X-Ray experiment was flown August 26th 1979 from the Milo Base (Sicily, Italy) and a 27-hour flight was achieved. The scientific payload consisted of two Multiwire Spectroscopic Proportional Counters with 900 cm 2 sensitive geometric area each, in the hard X-Ray range (16 to 180 keV). A single drift scan was performed on the Crab Nebula region after the balloon reached the flotation point (2.9 mbar). The observation gave a maximum counting rate of about 25 counts/s superimposed on a background of about 75 counts/s. The Crab power-law spectrum was observed, and these data provide evidence for a line emission enhancement around 70 keV. (author)

Neutron total cross section measurements in the energy region from 47 keV to 20 MeV

International Nuclear Information System (INIS)

Poenitz, W.P.; Whalen, J.F.

1983-05-01

Neutron total cross sections were measured for 26 elements. Data were obtained in the energy range from 47 keV to 20 MeV for 11 elements in the range of light-mass fission products. Previously reported measurements for eight heavy and actinide isotopes were extended to 20 MeV. Data were also obtained for Cu (47 keV to 1.4 MeV) and for Sc, Zn, Nd, Hf, and Pt (1.8 to 20 MeV). The present work is part of a continuing effort to provide accurate neutron total cross sections for evaluations and for optical-model parameteriztions. The latter are required for the derivation of other nuclear-data information of importance to applied programs. 37 references

Electron scattering by Ne, Ar and Kr at intermediate and high energies, 0.5-10 keV

Energy Technology Data Exchange (ETDEWEB)

Garcia, G.; Roteta, M.; Manero, F. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), Departamento de Fusion y Particulas Elementales, Madrid (Spain); Blanco, F. [Universidad Complutense de Madrid, Facultad de Fisica, Departamento de Fisica Atomica Molecular y Nuclear, Madrid (Spain); Williart, A. [Universidad Nacional de Educacion a Distancia, Facultad de Ciencias, Departamento de Fisica de los Materiales, Madrid (Spain)

1999-04-28

Semi-empirical total cross sections for electron scattering of noble gases (Ne, Ar and Kr) in the energy range 0.5-10 keV have been obtained by combining transmission-beam measurements for impact energies up to 6 keV with an asymptotic behaviour at higher energies according to the Born-Bethe approximation. The influence of the forward electron scattering on the experimental system has been evaluated by means of a Monte Carlo electron transport simulation. Theoretical values have also been obtained by applying the Born approximation in the case of inelastic processes and by means of an atomic scattering potential for the elastic part. The results of these calculations show an excellent agreement with the semi-empirical values in the above-mentioned energy range. (author)

Studies on effective atomic numbers and electron densities in amino acids and sugars in the energy range 30-1333 keV

International Nuclear Information System (INIS)

Gowda, Shivalinge; Krishnaveni, S.; Gowda, Ramakrishna

2005-01-01

The effective atomic numbers and electron densities of the amino acids glycine, alanine, serine, valine, threonine, leucine, isoleucine, aspartic acid, lysine, glutamic acid, histidine, phenylalanine, arginine, tyrosine, tryptophane and the sugars arabinose, ribose, glucose, galactose, mannose, fructose, rhamnose, maltose, melibiose, melezitose and raffinose at the energies 30.8, 35.0, 81.0, 145, 276.4, 302.9, 356, 383.9, 661.6, 1173 and 1332.5 keV were calculated by using the measured total attenuation cross-sections. The interpolations of total attenuation cross-sections for photons of energy E in elements of atomic number Z was performed using the logarithmic regression analysis of the XCOM data in the photon energy region 30-1500 keV. The best-fit coefficients obtained by a piece wise interpolation method were used to find the effective atomic number and electron density of the compounds. These values are found to be in good agreement with the theoretical values calculated based on XCOM data

Studies on effective atomic numbers and electron densities in amino acids and sugars in the energy range 30-1333 keV

Energy Technology Data Exchange (ETDEWEB)

Gowda, Shivalinge [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India); Krishnaveni, S. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India); Gowda, Ramakrishna [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India)]. E-mail: ramakrishnagowda@yahoo.com

2005-10-15

The effective atomic numbers and electron densities of the amino acids glycine, alanine, serine, valine, threonine, leucine, isoleucine, aspartic acid, lysine, glutamic acid, histidine, phenylalanine, arginine, tyrosine, tryptophane and the sugars arabinose, ribose, glucose, galactose, mannose, fructose, rhamnose, maltose, melibiose, melezitose and raffinose at the energies 30.8, 35.0, 81.0, 145, 276.4, 302.9, 356, 383.9, 661.6, 1173 and 1332.5 keV were calculated by using the measured total attenuation cross-sections. The interpolations of total attenuation cross-sections for photons of energy E in elements of atomic number Z was performed using the logarithmic regression analysis of the XCOM data in the photon energy region 30-1500 keV. The best-fit coefficients obtained by a piece wise interpolation method were used to find the effective atomic number and electron density of the compounds. These values are found to be in good agreement with the theoretical values calculated based on XCOM data.

Low-energy x-ray dosimetry studies (6 to 16 keV) at SSRL beamline 1-5

International Nuclear Information System (INIS)

Ipe, N.E.; Chatterji, S.; Fassograve, A.; Kase, K.R.; Seefred, R.; Bilski, P.; Soares, C.

1997-01-01

Synchrotron radiation facilities provide a unique opportunity for low-energy x-ray dosimetry studies because of the availability of monochromatic x-ray beams. Results of such studies performed at the Stanford Synchrotron Radiation Laboratory (SSRL) are described. Polish lithium fluoride thermoluminescent dosemeters (TLDs), MTS-N(LiF:Mg, Ti- 0.4 mm thick), MCP-N (LiF:Mg, Cu, P - 0.4 mm thick) were exposed free in air to monochromatic x-rays (6 - 16 keV). These exposures were monitored with an SSRL ionization chamber. The responses (counts/Gy) of MTS-N and MCP-N were generally found to increase with increasing energy. The response at 16 keV is about 3 and 4 times higher than the response at 6 keV for MTS-N and MCP-N, respectively. Irradiation at 6 keV indicates a fairly linear dose response for both type of TLDs over a dose range of 0.01 to 0.4 Gy. In addition there appears to be no significant difference in responses between irradiating the TLDs from the front and the back sides. The energy response of the PTW ionization chamber type 23342 relative to the SSRL ionization chamber is within ±4.5% between 6 and 16 keV. Both the TLDs and the PTW ionization chamber can also be used for beam dosimetry. copyright 1997 American Institute of Physics

The Galactic 511 keV line: analysis and interpretation of Integral observations

International Nuclear Information System (INIS)

Lonjou, V.

2005-09-01

Ever since the discovery of the 511 keV annihilation line emission from the galactic center region in the late seventies, the origin of galactic positrons has been the topic of a vivid scientific debate. It is also one of the prime scientific objectives of the imaging spectrometer SPI on board ESA's INTEGRAL observatory. In this thesis first a description of the most important SPI sub-system is given - the detector plane. Procedures for detector energy calibration and detector degradation analysis are developed. The determination of instrumental background models, a crucial aspect of data analysis, is elaborated. These background models are then applied to deriving sky maps and spectra of unprecedented quality of the Galactic positron annihilation radiation. The emission is centered on the galactic center with a spatial resolution of 8 degrees (FWHM), a second spatial component appears clearly: the galactic disc. The ray energy has been measured with unprecedented accuracy: 511.0 ± 0.03 keV for a full width at half maximum (FWHM) of 2.07 ± 0.1 keV. The total galactic flux ranges from 1.09 to 2.43 10 -3 ph.cm -2 .s -1 including uncertainties on spatial distribution. Finally, the implications of these observations for the production of positrons by various Galactic populations are discussed

Test of a compact 750 keV H- preinjector

International Nuclear Information System (INIS)

Meitzler, C.R.; Datte, P.; Huson, F.R.; Kazimi, R.; Kronke, C.; Machida, S.; MacKay, W.; Ohnuma, S.; Raparia, D.; Sun, D.; Tompkins, P.; Ziegler, J.

1989-01-01

A 750 keV RFQ based accelerator is being developed at the Texas Accelerator Center. A modified magnetron ion source will produce 10--100 mA of 30 keV H - beam. A 35 keV transport line that transports the beam from the ion source to the entrance of the RFQ without becoming neutralized has been designed and is under construction. The RFQ is a 86 cm long, four rod structure that operates at 470 MHz. Results of tests on the cold model are reported. 5 refs

Atomic mixing effects on high fluence Ge implantation into Si at 40 keV

International Nuclear Information System (INIS)

Gras-Marti, A.; Jimenez-Rodriguez, J.J.; Peon-Fernandez, J.; Rodriguez-Vidal, M.; Tognetti, N.P.; Carter, G.; Nobes, M.J.; Armour, D.G.

1982-01-01

Ion implanted profiles of 40 keV Ge + into Si at fluences ranging from approx. equal to 10 15 ions/cm 2 up to saturation have been measured using the RBS technique. The profiles compare well with the predictions of an analytical model encompasing sputter erosion plus atomic relocation. (orig.)

Slowing down of 100 keV antiprotons in Al foils

Science.gov (United States)

Nordlund, K.

2018-03-01

Using energy degrading foils to slow down antiprotons is of interest for producing antihydrogen atoms. I consider here the slowing down of 100 keV antiprotons, that will be produced in the ELENA storage ring under construction at CERN, to energies below 10 keV. At these low energies, they are suitable for efficient antihydrogen production. I simulate the antihydrogen motion and slowing down in Al foils using a recently developed molecular dynamics approach. The results show that the optimal Al foil thickness for slowing down the antiprotons to below 5 keV is 910 nm, and to below 10 keV is 840 nm. Also the lateral spreading of the transmitted antiprotons is reported and the uncertainties discussed.

Measurement of the 232Th capture cross section in the energy region 5 keV-150 keV

International Nuclear Information System (INIS)

Lobo, G.; Schillebeeckx, P.; Brusegan, A.; Borella, A.; Corvi, F.; Janeva, N.; Volev, K.

2003-01-01

The 232 Th(n,γ) neutron capture cross-section is of great importance for accelerator driven reactor (ADS) systems based on the Thorium-Uranium fuel cycle. An analysis of the required nuclear data, reveals that the status of the 232 Th capture data is far from the requested 2 % uncertainty level. Recently 232 Th average capture measurements, between 5-200 keV neutron energy, were performed at the FzK Karlsruhe (DE). A comparison of the measured averaged capture cross section with the evaluated data files shows a reasonable agreement in the neutron energy range above 15 keV. However, discrepancies of up to 40 % at lower neutron energies are observed. The same order of discrepancies is observed when comparing their results with the results obtained by Macklin et al. at ORELA. To clarify these discrepancies we measured at IRMM the average capture cross-section at the GEel LINear Accelerator (GELINA). The measurements were performed at a 14.37 m flight-path using the Time-Of-Flight (TOF) method. The gamma rays, originating from the 232 Th(n,γ) reaction, were detected by a pair of C 6 D 6 -based liquid scintillators applying a pulse-height weighting method. The neutron flux was measured with an ionisation chamber placed at 80 cm before the Thorium sample. This chamber has a cathode loaded with two back-to-back layers of about 40 μg/cm 2 10 B. The sample consisted of a metallic natural thorium disc of 8 cm diameter and 0.5 mm thick, corresponding to a thickness of 1.588 10 -3 at/b. The background for the capture measurements consists of a time independent and time dependent component. The former, mainly produced by the radioactive decay of the sample, was deduced from measurements with a closed beam. The latter was measured by replacing the thorium sample with a 0.5 mm thick 208 Pb sample of the same size. Such a Pb sample has practically the same scattering probability as the thorium sample and has a negligible capture yield. Therefore, the 208 Pb run provides a good

Efficient laser-induced 6-8 keV x-ray production from iron oxide aerogel and foil-lined cavity targets

Energy Technology Data Exchange (ETDEWEB)

Pérez, F.; Kay, J. J.; Patterson, J. R.; Kane, J.; Villette, B.; Girard, F.; Reverdin, C.; May, M.; Emig, J.; Sorce, C.; Colvin, J.; Gammon, S.; Jaquez, J.; Satcher, J. H.; Fournier, K. B.

2012-08-01

The performance of new iron-based laser-driven x-ray sources has been tested at the OMEGA laser facility for production of x rays in the 6.5–8.5 keV range. Two types of targets were experimentally investigated: low-density iron oxide aerogels (density 6-16 mg/cm36-16 mg/cm3) and stainless steel foil-lined cavity targets (steel thickness 1-5 μm1-5 μm). The targets were irradiated by 40 beams of the OMEGA laser (500 J/beam, 1 ns pulse, wavelength 351 nm). All targets showed good coupling with the laser, with <5%<5% of the incident laser light backscattered by the resulting plasma in all cases (typically <2.5%<2.5%). The aerogel targets produced Te=2Te=2 to 3 keV, ne=0.12-0.2ne=0.12-0.2 critical density plasmas yielding a 40%–60% laser-to-x-ray total conversion efficiency (CE) (1.2%–3% in the Fe K-shell range). The foil cavity targets produced Te~2 keV, T_e~2 keV, n_e~0.15ne~0.15 critical density plasmas yielding a 60%–75% conversion efficiency (1.6%–2.2% in the Fe K-shell range). Time-resolved images illustrate that the volumetric heating of low-density aerogels allow them to emit a higher K-shell x-ray yield even though they contain fewer Fe atoms. However, their challenging fabrication process leads to a larger shot-to-shot variation than cavity targets.

The decay of 399 KeV isomeric state in 197Pt

International Nuclear Information System (INIS)

Soares, J.C.; Melo, A.A.; Gil, F.B.; Dias, H.

1981-02-01

The nuclear levels in 197 Pt have been studied from decay of 95.4 min 197 (sup m)Pt. The isomeric state was produced by (n,#betta#) reaction on the enriched 196 Pt. The #betta#-ray spectra have been observed with a hyperpure Ge detector and a large volume Ge(Li) detector. The half lives of the 399 KeV and the 53 KeV states were determined with improved precision. The results are: T1/2 (399 KeV) = 95.41 +- 0.18 min and T1/2(53 KeV) = 16.58 +- 0.17 ns. The g-factor of the 53 Kev 5/2 - state has been measured by the gamma-gamma time differential perturbed angular correlation (TDPAC) method in an external magnetic field of 25,1 kG using the 346 - 53 KeV gamma cascade. The value of g-factor was obtained to be + 0.335 +- 0.010. This result is compared with the known g-factors of the similar states in 195 Pt, and in 197 Hg and 199 Hg and also with the theoretical calculations based on the quasiparticle-phonon coupling scheme. Possibility of using the 346 - 53 KeV gamma cascade in 197 Pt in the future TDPAC studies is discussed. (Author) [pt

VOXES: a high precision X-ray spectrometer for diffused sources with HAPG crystals in the 2–20 keV range

Science.gov (United States)

Scordo, A.; Curceanu, C.; Miliucci, M.; Shi, H.; Sirghi, F.; Zmeskal, J.

2018-04-01

Bragg spectroscopy is one of the best established experimental methods for high energy resolution X-ray measurements and has been widely used in several fields, going from fundamental physics to quantum mechanics tests, synchrotron radiation and X-FEL applications, astronomy, medicine and industry. However, this technique is limited to the measurement of photons produced from well collimated or point-like sources and becomes quite inefficient for photons coming from extended and diffused sources like those, for example, emitted in the exotic atoms radiative transitions. The VOXES project's goal is to realise a prototype of a high resolution and high precision X-ray spectrometer, using Highly Annealed Pyrolitic Graphite (HAPG) crystals in the Von Hamos configuration, working also for extended sources. The aim is to deliver a cost effective system having an energy resolution at the level of eV for X-ray energies from about 2 keV up to tens of keV, able to perform sub-eV precision measurements with non point-like sources. In this paper, the working principle of VOXES, together with first results, are presented.

Experimental investigation of dd reaction in range of ultralow energies using Z-pinch

International Nuclear Information System (INIS)

Bystritskij, V.M.; Grebenyuk, V.M.; Parzhitskij, S.S.

1998-01-01

Results of the experiments to measure the dd reaction cross section in the range of deuteron collision energies from 0.1 keV to 1.5 keV using Z-pinch technique are presented. The experiment was performed at the Pulsed Ion Beam Accelerator of the High-Current Electronics Institute in Tomsk. The dd fusion neutrons were registered by scintillation detectors using time-of-flight method and BF 3 detectors of thermal neutrons. At 90% confidence level, the upper limits of the neutron producing dd reaction cross sections are obtained for average deuteron collision energies of 0.11, 0.34, 0.37 and 1.46 keV. The results demonstrate that high-intensity pulsed accelerators with a generator current of 2-3 MA allow the dd reaction cross sections to be measured in the range of deuteron collision energies from 0.8 keV to 3 keV

Inelastic scattering of 275 keV neutrons by silver

International Nuclear Information System (INIS)

Litvinsky, L.L.; Zhigalov, Ya.A.; Krivenko, V.G.; Purtov, O.A.; Sabbagh, S.

1997-01-01

Neutron total, elastic and inelastic scattering cross-scattering of Ag at the E n = 275 KeV neutron energy were measured by using the filtered neutron beam of the WWR-M reactor in Kiev. The d-neutron strength function S n2 of Ag was determined from the analysis of all available data in the E n ≤ keV energy region on neutron inelastic scattering cross-sections with excitation of the first isomeric levels I π m = 7/2 + , E m ∼ 90 keV of 107,109 Ag: S n2 = (1.03 ± 0.19) · 10 -4 . (author). 10 refs, 3 figs

Neutron capture cross sections of 69Ga and 71Ga at 25 keV and Epeak = 90 keV

Science.gov (United States)

Göbel, Kathrin; Beinrucker, Clemens; Erbacher, Philipp; Fiebiger, Stefan; Fonseca, Micaela; Heftrich, Michael; Heftrich, Tanja; Käppeler, Franz; Krása, Antonin; Lederer-Woods, Claudia; Plag, Ralf; Plompen, Arjan; Reifarth, René; Schmidt, Stefan; Sonnabend, Kerstin; Weigand, Mario

2017-09-01

We measured the neutron capture cross sections of 69Ga and 71Ga for a quasi-stellar spectrum at kBT = 25 keV and a spectrum with a peak energy at 90 keV by the activation technique at the Joint Research Centre (JRC) in Geel, Belgium. Protons were provided by an electrostatic Van de Graaff accelerator to produce neutrons via the reaction 7Li(p,n). The produced activity was measured via the γ emission of the product nuclei by high-purity germanium detectors. We present preliminary results.

Evaluation of 235U(n,f) between 100 keV and 20 MeV

International Nuclear Information System (INIS)

Poenitz, W.P.

1979-07-01

The 235 U(n,f) cross section is evaluated in the energy range from 100 keV to 20 MeV. Experimental data are included up to the 1978 Harwell Conference on Neutron Physics. The evaluation methodology is discussed in detail. The shape and the normalization of the cross section are evalutated in separate steps. An extensive comparison of the evaluation result with experimental data sets is made. The shape of the cross section obtained in a preliminary version of the present evaluation and a normalization factor extracted from data provided within the framework of this evaluation were used by the Subcommittee on Standards and Normalizations of the Cross Sections Evaluation Working Group to establish 235 U(n,f) for ENDF/B-V above 100 keV. 20 figures, 6 tables

Direct and indirect signal detection of 122 keV photons with a novel detector combining a pnCCD and a CsI(Tl) scintillator

Energy Technology Data Exchange (ETDEWEB)

Schlosser, D.M., E-mail: dieter.schlosser@pnsensor.de [PNSensor GmbH, Sckellstraße 3, 81667 München (Germany); Huth, M.; Hartmann, R. [PNSensor GmbH, Sckellstraße 3, 81667 München (Germany); Abboud, A.; Send, S. [Universität Siegen, Walter-Flex-Straße 3, 57072 Siegen (Germany); Conka-Nurdan, T. [Türkisch-Deutsche Universität, Sakinkaya Cad. 86, Beykoz, 34820 Istanbul (Turkey); Shokr, M.; Pietsch, U. [Universität Siegen, Walter-Flex-Straße 3, 57072 Siegen (Germany); Strüder, L. [PNSensor GmbH, Sckellstraße 3, 81667 München (Germany); Universität Siegen, Walter-Flex-Straße 3, 57072 Siegen (Germany)

2016-01-01

By combining a low noise fully depleted pnCCD detector with a CsI(Tl) scintillator, an energy-dispersive area detector can be realized with a high quantum efficiency (QE) in the range from below 1 keV to above 100 keV. In direct detection mode the pnCCD exhibits a relative energy resolution of 1% at 122 keV and spatial resolution of less than 75 µm, the pixel size of the pnCCD. In the indirect detection mode, i.e. conversion of the incoming X-rays in the scintillator, the measured energy resolution was about 9–13% at 122 keV, depending on the depth of interaction in the scintillator, while the position resolution, extracted with the help of simulations, was 30 µm only. We show simulated data for incident photons of 122 keV and compare the various interaction processes and relevant physical parameters to experimental results obtained with a radioactive {sup 57}Co source. - Highlights: • Position and energy resolving pnCCD+CsI(Tl) detector for energies from 1-150 keV • Detection in the pnCCD (122keV): 1% energy and <75µm spatial resolution • Detection in the scintillator (122keV): 9-12% energy and ~30µm spatial resolution.

Energy dependence of the air kerma response of a liquid ionization chamber at photon energies between 8 keV and 1250 keV

International Nuclear Information System (INIS)

Hilgers, G.; Bahar-Gogani, J.; Wickman, G.

2002-01-01

Full text: In its recent reports on cardiovascular brachytherapy the DGMP recommends the source strength of brachytherapy sources being characterized in terms of absorbed dose to water at a distance of 2 mm from the central axis of the source. As a consequence, the response of a detector suitable for characterizing such sources with respect to absorbed dose to water should depend only to a small extent on radiation energy. Additionally, the detection volume of the detector has to be sufficiently small for the necessary spatial resolution to be obtained. The liquid ionization chamber as described in seems to be a promising means for this type of measurements. The two components of the ionization liquid (TMS and isooctane) can be mixed in a ratio which ensures that the mass-energy absorption coefficient of the resulting mixture deviates from that of water by less than ±15 % down to photon energies of 10 keV. Due to the high density of the ionization medium, the spacing between the two electrodes of the ionization chamber can be made as small as a few tenths of a millimeter and still the resulting ionization current is sufficiently large. The ionization chamber used in the present investigation is a plane parallel chamber 5 mm in diameter and of 0.3 mm electrode spacing. The ionization medium is a mixture of 40 % TMS and 60 % isooctane. The irradiations were carried out with the ISO wide spectra series with tube voltages between 10 kV and 300 kV and with 137 Cs and 60 Co γ-radiation. As a first step, the response of the liquid ionization chamber was investigated with respect to air kerma instead of absorbed dose to water. Although the mass-energy absorption coefficient of the liquid deviates from that of air by less than ±10 % over the photon energy range, the measured chamber response varies by a factor of about 3.5. Monte Carlo calculations carried out with EGSnrc show a variation of the chamber response smaller than ±20 %. Measurements of the ion yield of the

Anisotropic pitch angle distribution of ~100 keV microburst electrons in the loss cone: measurements from STSAT-1

Directory of Open Access Journals (Sweden)

J. J. Lee

2012-11-01

Full Text Available Electron microburst energy spectra in the range of 170 keV to 360 keV have been measured using two solid-state detectors onboard the low-altitude (680 km, polar-orbiting Korean STSAT-1 (Science and Technology SATellite-1. Applying a unique capability of the spacecraft attitude control system, microburst energy spectra have been accurately resolved into two components: perpendicular to and parallel to the geomagnetic field direction. The former measures trapped electrons and the latter those electrons with pitch angles in the loss cone and precipitating into atmosphere. It is found that the perpendicular component energy spectra are harder than the parallel component and the loss cone is not completely filled by the electrons in the energy range of 170 keV to 360 keV. These results have been modeled assuming a wave-particle cyclotron resonance mechanism, where higher energy electrons travelling within a magnetic flux tube interact with whistler mode waves at higher latitudes (lower altitudes. Our results suggest that because higher energy (relativistic microbursts do not fill the loss cone completely, only a small portion of electrons is able to reach low altitude (~100 km atmosphere. Thus assuming that low energy microbursts and relativistic microbursts are created by cyclotron resonance with chorus elements (but at different locations, the low energy portion of the microburst spectrum will dominate at low altitudes. This explains why relativistic microbursts have not been observed by balloon experiments, which typically float at altitudes of ~30 km and measure only X-ray flux produced by collisions between neutral atmospheric particles and precipitating electrons.

Sensitometric characteristics of UF-4, UF-5, and UFSh-O films in the quantum-energy range of 5-30 keV

International Nuclear Information System (INIS)

Datsko, I.M.; Slabkovskaya, M.A.; Sokolov, A.S.; Uvarova, N.V.; Sheromov, M.A.

1987-01-01

The sensitivity, gamma, and transmission of UF-4, UF-5, and UFSh-O for quanta with energies of 5-30 keV extracted from a beam of synchrotron radiation are measured. UFSh-O photographic film is more sensitive by a factor of 1.5-2 than are the UF-4 and UF-5 films. The gamma of all the films is greatly dependent on the quantum energy

Study on the keV neutron capture reaction in 56Fe and 57Fe

Science.gov (United States)

Wang, Taofeng; Lee, Manwoo; Kim, Guinyun; Ro, Tae-Ik; Kang, Yeong-Rok; Igashira, Masayuki; Katabuchi, Tatsuya

2014-03-01

The neutron capture cross-sections and the radiative capture gamma-ray spectra from the broad resonances of 56Fe and 57Fe in the neutron energy range from 10 to 90keV and 550keV have been measured with an anti-Compton NaI(Tl) detector. Pulsed keV neutrons were produced from the 7Li 7Be reaction by bombarding the lithium target with the 1.5ns bunched proton beam from the 3MV Pelletron accelerator. The incident neutron spectrum on a capture sample was measured by means of a time-of-flight (TOF) method with a 6Li -glass detector. The number of weighted capture counts of the iron or gold sample was obtained by applying a pulse height weighting technique to the corresponding capture gamma-ray pulse height spectrum. The neutron capture gamma-ray spectra were obtained by unfolding the observed capture gamma-ray pulse height spectra. To achieve further understanding on the mechanism of neutron radiative capture reaction and study on physics models, theoretical calculations of the -ray spectra for 56Fe and 57Fe with the POD program have been performed by applying the Hauser-Feshbach statistical model. The dominant ingredients to perform the statistical calculation were the Optical Model Potential (OMP), the level densities described by the Mengoni-Nakajima approach, and the -ray transmission coefficients described by -ray strength functions. The comparison of the theoretical calculations, performed only for the 550keV point, show a good agreement with the present experimental results.

New Observations of Soft X-ray (0.5-5 keV) Solar Spectra

Science.gov (United States)

Caspi, A.; Woods, T. N.; Mason, J. P.; Jones, A. R.; Warren, H. P.

2013-12-01

The solar corona is the brightest source of X-rays in the solar system, and the X-ray emission is highly variable on many time scales. However, the actual solar soft X-ray (SXR) (0.5-5 keV) spectrum is not well known, particularly during solar quiet periods, as, with few exceptions, this energy range has not been systematically studied in many years. Previous observations include high-resolution but very narrow-band spectra from crystal spectrometers (e.g., Yohkoh/BCS), or integrated broadband irradiances from photometers (e.g., GOES/XRS, TIMED/XPS, etc.) that lack detailed spectral information. In recent years, broadband measurements with moderate energy resolution (~0.5-0.7 keV FWHM) were made by SphinX on CORONAS-Photon and SAX on MESSENGER, although they did not extend to energies below ~1 keV. We present observations of solar SXR emission obtained using new instrumentation flown on recent SDO/EVE calibration rocket underflights. The photon-counting spectrometer, a commercial Amptek X123 with a silicon drift detector and an 8 μm Be window, measures the solar disk-integrated SXR emission from ~0.5 to >10 keV with ~0.15 keV FWHM resolution and 1 s cadence. A novel imager, a pinhole X-ray camera using a cooled frame-transfer CCD (15 μm pixel pitch), Ti/Al/C filter, and 5000 line/mm Au transmission grating, images the full Sun in multiple spectral orders from ~0.1 to ~5 nm with ~10 arcsec/pixel and ~0.01 nm/pixel spatial and spectral detector scales, respectively, and 10 s cadence. These instruments are prototypes for future CubeSat missions currently being developed. We present new results of solar observations on 04 October 2013 (NASA sounding rocket 36.290). We compare with previous results from 23 June 2012 (NASA sounding rocket 36.286), during which solar activity was low and no signal was observed above ~4 keV. We compare our spectral and imaging measurements with spectra and broadband irradiances from other instruments, including SDO/EVE, GOES/XRS, TIMED

Resonance parameters for measured keV neutron capture cross sections

Energy Technology Data Exchange (ETDEWEB)

Musgrove, A.R. de L

1969-05-01

All available neutron capture cross sections in the keV region ({approx} to 100 keV) have been fitted with resonance parameters. Capture cross sections for nuclides with reasonably well known average s-wave parameters, but no measured cross section, have been calculated and tabulated using p-and d- wave strength functions interpolated between fitted values. Several of these nuclides are of interest in the theory of slow nucleosynthesis of heavy elements in stars, and the product of cosmic abundance (due to the s-process) and capture cross section at 30 keV has been plotted versus mass number. (author)

Polarized proton capture reaction /sup 7/Li(p,. gamma. )/sup 8/Be in the energy range from 380 to 960 keV

Energy Technology Data Exchange (ETDEWEB)

Ulbricht, J; Arnold, W; Berg, H; Huttel, E; Krause, H H; Clausnitzer, G [Giessen Univ. (Germany, F.R.). Abt. Grossgeraete (Angewandte Kernphysik)

1977-09-05

The polarized proton capture in /sup 7/Li was used to study the reaction mechanism and to obtain spectroscopic information on the /sup 8/Be nucleus. Gamma-ray angular distributions of the analyzing power were measured as a function of proton energy from Esub(p) = 380-960 keV with three Ge(Li) detectors simultaneously. The excitation functions of the cross section and the analyzing power are strongly energy dependent. The data were analyzed unambiguously and represented by three R-matrix elements, two M1 and one E1. The energy dependence of the two M1 matrix elements agrees with the well-known two 1/sup +/ resonances at Esub(x) = 17.642 and 18.157 MeV. The energy dependence of the E1 matrix element shows a smooth background presumably caused by a direct-capture mechanism, and furthermore, a resonant contribution, which is a significant suggestion of a new 1/sup -/ state in the /sup 8/Be system at Esub(x) = 17.70 MeV with a width of GAMMAsub(p) = 180 keV.

A 600 keV electron radiation accelerator

International Nuclear Information System (INIS)

Zhou Youyi; Wang Xurong

1995-01-01

The authors describe a 600 keV two-body multi-functional electron and positive ion radiation accelerator based on a 400 keV Cockroft-Walton, Which was successfully used to accelerate electron and positive ion. Through test on coating solidification of decoration materials, such as colorful surface plaster plate and relief plate, and researches on metal plate, plastic plate, wood and paper coating decorations and radiation workmanship, as well as experiment of brach-linking by radiation for filling materials of petroleum pipings, it is proved that the device is reliable and stable in operation and reaches the pre-set design indexes and satisfies the requirements called for

Resolved resonance parameters for uranium 238 from 4 to 6 keV

International Nuclear Information System (INIS)

Olsen, D.K.; Meszaros, P.S.

1982-01-01

Neutron widths for 145 resonances from 4 to 6 keV are reported from a least-squares shape analysis of the ORELA 150-m, 4-sample 238 U transmission data. The resultant s-wave strength function from 4 to 6 keV is found to be substantially smaller than that from 0 to 4 keV

Range distributions in multiply implanted targets

International Nuclear Information System (INIS)

Kostic, S.; Jimenez-Rodriguez, J.J.; Karpuzov, D.S.; Armour, D.G.; Carter, G.; Salford Univ.

1984-01-01

Range distributions in inhomogeneous binary targets have been investigated both theoretically and experimentally. Silicon single crystal targets [(111) orientation] were implanted with 40 keV Pb + ions to fluences in the range from 5x10 14 to 7.5x10 16 cm -2 prior to bombardment with 80 keV Kr + ions to a fluence of 5x10 15 cm -2 . The samples were analysed using high resolution Rutherford backscattering before and after the krypton implantation in order to determine the dependence of the krypton distribution on the amount of lead previously implanted. The theoretical analysis was undertaken using the formalism developed in [1] and the computer simulation was based on the MARLOWE code. The agreement between the experimental, theoretical and computational krypton profiles is very good and the results indicate that accurate prediction of ranges profiles in inhomogeneous binary targets is possible using available theoretical and computational treatments. (orig.)

An analytical X-ray CdTe detector response matrix for incomplete charge collection correction for photon energies up to 300 keV

Science.gov (United States)

Kurková, Dana; Judas, Libor

2018-05-01

Gamma and X-ray energy spectra measured with semiconductor detectors suffer from various distortions, one of them being so-called "tailing" caused by an incomplete charge collection. Using the Hecht equation, a response matrix of size 321 × 321 was constructed which was used to correct the effect of incomplete charge collection. The correction matrix was constructed analytically for an arbitrary energy bin and the size of the energy bin thus defines the width of the spectral window. The correction matrix can be applied separately from other possible spectral corrections or it can be incorporated into an already existing response matrix of the detector. The correction was tested and its adjustable parameters were optimized on the line spectra of 57Co measured with a cadmium telluride (CdTe) detector in a spectral range from 0 up to 160 keV. The best results were obtained when the values of the free path of holes were spread over a range from 0.4 to 1.0 cm and weighted by a Gauss function. The model with the optimized parameter values was then used to correct the line spectra of 152Eu in a spectral range from 0 up to 530 keV. An improvement in the energy resolution at full width at half maximum from 2.40 % ± 0.28 % to 0.96 % ± 0.28 % was achieved at 344.27 keV. Spectra of "narrow spectrum series" beams, N120, N150, N200, N250 and N300, generated with tube voltages of 120 kV, 150 kV, 200 kV, 250 kV and 300 kV respectively, and measured with the CdTe detector, were corrected in the spectral range from 0 to 160 keV (N120 and N150) and from 0 to 530 keV (N200, N250, N300). All the measured spectra correspond both qualitatively and quantitatively to the available reference data after the correction. To obtain better correspondence between N150, N200, N250 and N300 spectra and the reference data, lower values of the free paths of holes (range from 0.16 to 0.65 cm) were used for X-ray spectra correction, which suggests energy dependence of the phenomenon.

Cusp electron production in 75--300 keV He+ + Ar collisions

International Nuclear Information System (INIS)

Plano, V.L.; Sarkadi, L.; Zavodszky, P.; Berenyi, D.; Palinkas, J.; Gulyas, L.; Takacs, E.; Toth, L.; Tanis, J.A.

1992-01-01

Cusp-electron production has been investigated in collisions of 75--300 keV He + with Ar. The relative contributions from electron capture to the continuum (ECC), transfer ionization (TI), and electron loss to the continuum (ELC) to the total cusp electron production were measured. Over the energy range investigated, ECC was found to decrease from about 86% to 80%, TI decreased from about 12% to 1%, and ELC increased from about 2% to 20%. The present results are consistent with earlier work for He + and O q+ projectiles

Measurement of the x-ray mass attenuation coefficient and determination of the imaginary component of the atomic form factor of molybdenum over the 13.5-41.5-keV energy range

International Nuclear Information System (INIS)

Jonge, Martin D. de; Tran, Chanh Q.; Chantler, Christopher T.; Barnea, Zwi; Dhal, Bipin B.; Cookson, David J.; Lee, Wah-Keat; Mashayekhi, Ali

2005-01-01

We use the x-ray extended-range technique (XERT) [Chantler et al., Phys. Rev. A 64, 062506 (2001)] to measure the mass attenuation coefficients of molybdenum in the x-ray energy range of 13.5-41.5 keV to 0.02-0.15 % accuracy. Measurements made over an extended range of the measurement parameter space are critically examined to identify, quantify, and correct where necessary a number of experimental systematic errors. These results represent the most extensive experimental data set for molybdenum and include absolute mass attenuation coefficients in the regions of the x-ray absorption fine structure (XAFS) and x-ray-absorption near-edge structure (XANES). The imaginary component of the atomic form-factor f 2 is derived from the photoelectric absorption after subtracting calculated Rayleigh and Compton scattering cross sections from the total attenuation. Comparison of the result with tabulations of calculated photoelectric absorption coefficients indicates that differences of 1-15 % persist between the calculated and observed values

A new approach for precise measurements of keV neutron capture cross sections: The examples of 93Nb, 103Rh, and 181Ta

International Nuclear Information System (INIS)

Wisshak, K.; Voss, F.; Kaeppeler, F.; Reffo, G.

1990-04-01

A new experimental method has been implemented for precise measurements of neutron capture cross sections in the energy range from 3 to 200 keV. Neutrons are produced via the 7 Li(p,n) 7 Be reaction using a pulsed 3 MV Van de Graaff accelerator. The neutron energy is determined by the time of flight technique using flight paths of less than 1 m. Capture events are detected with the Karlsruhe 4π Barium Fluoride Detector. This detector is characterized by a resolution in gamma-ray energy of 14% at 662 keV and 7% at 2.5 MeV, a time resolution of 500 ps, and a peak efficiency of 90% at 1 MeV. Capture events are registered with ≅ 95% probability above a gamma-ray threshold of 2.5 MeV. The combined effect of the relatively short primary flight path, the 10 cm inner radius of the detector sphere, and of the low capture cross section of BaF 2 allows to discriminate the main background due to capture of sample scattered neutrons in the scintillator via time of flight, leaving part of the neutron energy range completely undisturbed. The high efficiency and good energy resolution for capture gamma-rays yields a further reduction of this background by using only the relevant energy channels for data evaluation. In the first measurements with the new detector, the neutron capture cross sections of 93 Nb, 103 Rh, and 181 Ta were determined in the energy range from 3 to 200 keV relative to gold as a standard. The cross section ratios could be determined with overall systematic uncertainties of 0.7 to 0.8%; statistical uncertainties were less than 1% in the energy range from 20 to 100 keV, if the data are combined in 20 keV wide bins. The necessary sample masses were of the order of one gram. Further improvements with respect to sensitivity and accuracy are discussed. (orig.) [de

Analytical dependence of effective atomic number on the elemental composition of matter and radiation energy in the range 10-1000 keV

Science.gov (United States)

Eritenko, A. N.; Tsvetiansky, A. L.; Polev, A. A.

2018-01-01

In the present paper, a universal analytical dependence of effective atomic number on the composition of matter and radiation energy is proposed. This enables one to consider the case of a strong difference in the elemental composition with respect to their atomic numbers over a wide energy range. The contribution of photoelectric absorption and incoherent and coherent scattering during the interaction between radiation and matter is considered. For energy values over 40 keV, the contribution of coherent scattering does not exceed approximately 10% that can be neglected at a further consideration. The effective atomic numbers calculated on the basis of the proposed relationships are compared to the results of calculations based on other methods considered by different authors on the basis of experimental and tabulated data on mass and atomic attenuation coefficients. The examination is carried out for both single-element (e.g., 6C, 14Si, 28Cu, 56Ba, and 82Pb) and multi-element materials. Calculations are performed for W1-xCux alloys (x = 0.35; x = 0.4), PbO, ther moluminescent dosimetry compounds (56Ba, 48Cd, 41Sr, 20Ca, 12Mg, and 11Na), and SO4 in a wide energy range. A case with radiation energy between the K- and L1-absorption edges is considered for 82Pb, 74W, 56Ba, 48Cd, and 38Sr. This enables to substantially simplify the calculation of the atomic number and will be useful in technical and scientific fields related to the interaction between X-ray/gamma radiation and matter.

Measurement of the G-value for 1. 5 keV X-rays

Energy Technology Data Exchange (ETDEWEB)

Freyer, J.P.; Schillaci, M.E.; Raju, M.R. (Los Alamos National Lab., NM (USA))

1989-12-01

Using a ferrous sulfate solution modified by the addition of benzoic acid, the authors measured relative G-values for Al{sub k} characteristic X-rays (1.5keV), {sup 238}Pu {alpha}-particles (3.7MeV), {sup 60}Co (1.17 MeV) and {sup 137}Cs (0.66 MeV){gamma}-rays. Relative ferrous-to-ferric conversions as a function of dose were similar for the two {gamma}-ray energies, yielding G-values of 1.62 and 1.59 {mu}mol J{sup -1} for the {sup 60}Co and {sup 137}Cs radiations. The {alpha}-particle G-value was 0.52 {mu}mol J{sup -1}, or 31% of that for {sup 60}Co {gamma}-rays. The Al{sub k} X-rays had a G-value of 0.92 {mu}mol J{sup -1} or 57% of that of the {sup 60}Co radiation. This G-value for 1.5 keV X-rays is within 20% of values predicted by current theories, and theoretical values are within the error range of the authors' measurements. (author).

Seeded quantum FEL at 478 keV

Energy Technology Data Exchange (ETDEWEB)

Guenther, Marc [Max-Planck-Institut fuer Quantenoptik, Garching (Germany); Thirolf, Peter; Seggebrock, Thorben [Ludwig-Maximilians-Universitaet Muenchen, Garching (Germany); Habs, Dietrich [Max-Planck-Institut fuer Quantenoptik, Garching (Germany); Ludwig-Maximilians-Universitaet Muenchen, Garching (Germany)

2012-07-01

We present for the first time a concept for a seeded {gamma} quantum Free Electron Laser (QFEL) at 478 keV (transition in {sup 7}Li). To produce a highly intense and coherent {gamma} beam, we intend to use a seeded FEL scheme. Important for the production of a highly brilliant and coherent {gamma} beam are novel refractive {gamma} lenses for focusing and an efficient monochromator, allowing to generate a very intense and coherent seed beam. To realize such a coherent {gamma} beam at 478 keV (1/38 A), it is suitable to use a quantum FEL design based on a new ''asymmetric'' laser-electron Compton back scattering scheme as pursued for the MeGaRay and ELI-NP facilities. Here the pulse length of the laser is much longer than the electron bunch length, equivalent to a {gamma}-FEL with laser wiggler. The coherence of a seeded QFEL can open up totally new areas of fundamental physics and applications. Especially, 478 keV can be attractive for ''green energy'' and life-science research, such as the detection of Li deposition in the brain for manic-depressive psychosis treatment with high spatial resolution or isotope-specific nuclear waste management and treatment.

A measuring method of photo-electric cross section. Application to high-Z elements between 40 keV and 220 keV. Measurement of K absorption edge energy of Au, Th, U, Pu

International Nuclear Information System (INIS)

Chartier, J.-L.

1977-09-01

This study first describes a bent crystal monochromator developed for the production of monochromatic beams in a continuous energy range from 30 to 250 keV; it is completed by a metrological application of the device (determination of K absorption edge energy of Au, Th, U, Pu). A method and the associated experimental procedure were developed to measure the photo-electric cross section for high-Z elements; the results are presented with a relative uncertainty ranging between 3 and 6%. Finally, the experimental values are compared with values calculated from theories using self-consistent potential models [fr

Effect of 200 keV Ar+ implantation on optical & electrical properties of polyethyleneterepthalate (PET)

Science.gov (United States)

Kumar, Rajiv; Goyal, Meetika; Sharma, Ambika; Aggarwal, Sanjeev; Sharma, Annu; Kanjilal, D.

2015-05-01

In the present paper we have discussed the effect of 200 keV Ar+ ions on the electrical and optical properties of PET samples. PET samples were implanted with 200 keV Ar+ ions to various doses ranging from 1×1015 to 1×1017 Ar+ cm2. The changes in the electrical and optical properties of pristine and implanted PET specimens have been studied by using Keithley electrometer and UV-Visible absorption spectroscopy. The electrical conductivity has found to be increased with increasing ion dose. The optical studies have revealed the drastic alterations in optical band gap from 3.63 eV to 1.48 eV and also increase in number of carbon atoms per cluster from 215 to 537. Further, the change in the electrical conductivity and optical band gap has also been correlated with the formation of conductive islands in the implanted layers of PET.

Total electron scattering cross sections of molecules containing H, C, N, O and F in the energy range 0.2–6.0 keV

Energy Technology Data Exchange (ETDEWEB)

Gurung, Meera Devi; Ariyasinghe, W.M., E-mail: wickram_ariyasinghe@baylor.edu

2017-03-15

Based on the effective atomic total electron scattering cross sections (EATCS) of atoms in a molecular environment, a simple model is proposed to predict the total electron scattering cross sections (TCS) of H, C, N, O, and F containing molecules. The EATCS for these five atoms are reported for 0.2–6.0 keV energies. The predicted TCS by this model are compared with experimental TCS in the literature. The experimental TCS of CHF{sub 3}, C{sub 2}F{sub 4}, C{sub 2}F{sub 2}H{sub 2}, C{sub 4}F{sub 6}, and c-C{sub 4}F{sub 8} have been obtained for 0.2–4.5 keV electrons by measuring the attenuation of the electron beam through a gas cell.

Explanation of the 511 keV line. Cascade annihilating dark matter with the {sup 8}Be anomaly

Energy Technology Data Exchange (ETDEWEB)

Jia, Lian-Bao [Southwest University of Science and Technology, School of Science, Mianyang (China)

2018-02-15

A possible dark matter (DM) explanation about the long-standing issue of the Galactic 511 keV line is explored in this paper. For DM cascade annihilations of concern, a DM pair π{sub d}{sup +}π{sub d}{sup -} annihilates into unstable π{sub d}{sup 0}π{sub d}{sup 0}, and π{sub d}{sup 0} decays into e{sup +}e{sup -} with new interactions suggested by the {sup 8}Be anomaly. Considering the constraints from the effective neutrino number N{sub eff} and the 511 keV gamma-ray emission, a range of DM is obtained, 11.6 keV line. The MeV scale DM may be searched by the DM-electron scattering, and the upper limit set by the CMB s-wave annihilation is derived in DM direct detections. (orig.)

Relative efficiency calibration between two silicon drift detectors performed with a monochromatized X-ray generator over the 0.1-1.5 keV range

Science.gov (United States)

Hubert, S.; Boubault, F.

2018-03-01

In this article, we present the first X-ray calibration performed over the 0.1-1.5 keV spectral range by means of a soft X-ray Manson source and the monochromator SYMPAX. This monochromator, based on a classical Rowland geometry, presents the novelty to be able to board simultaneously two detectors and move them under vacuum in front of the exit slit of the monochromatizing stage. This provides the great advantage to perform radiometric measurements of the monochromatic X-ray photon flux with one reference detector while calibrating another X-ray detector. To achieve this, at least one secondary standard must be operated with SYMPAX. This paper presents thereby an efficiency transfer experiment between a secondary standard silicon drift detector (SDD), previously calibrated on BESSY II synchrotron Facility, and another one ("unknown" SDD), devoted to be used permanently with SYMPAX. The associated calibration process is described as well as corresponding results. Comparison with calibrated measurements performed at the Physikalisch-Technische Bundesanstalt (PTB) Radiometric Laboratory shows a very good agreement between the secondary standard and the unknown SDD.

56Fe resonance parameters for neutron energies up to 850 keV

International Nuclear Information System (INIS)

Perey, C.M.; Perey, F.G.; Harvey, J.A.; Hill, N.W.; Larson, N.M.

1990-12-01

High-resolution neutron measurements for 56 Fe-enriched iron targets were made at the Oak Ridge Electron Linear Accelerator (ORELA) in transmission below 20 MeV and in differential elastic scattering below 5 MeV. Transmission measurements were also performed with a natural iron target below 160 keV. The transmission data were analyzed from 5 to 850 keV with the multilevel R-matrix code SAMMY which uses Bayes' theorem for the fitting process. This code provides energies and neutron widths of the resonances inside the 5- to 850-keV energy region, as well as possible parameterization for resonances external to the analyzed region to describe the smooth cross section from a few eV to 850 keV. The resulting set of resonance parameters yields the accepted values for the thermal total and capture cross sections. The differential elastic-scattering data at several scattering angles were compared to theoretical calculations from 40 to 850 keV using the R-matrix code RFUNC based on the Blatt-Biedenharn formalism. Various combinations of spin and parity were tried to predict cross sections for the well defined ell > 0 resonances; comparison of these predictions with the data allowed us to determine the most likely spin and parity assignments for these resonances. The results of a capture data analysis by Corvi et al. (COR84), from 2 to 350 keV, were combined with our results to obtain the radiation widths of the resonances below 350 keV observed in transmission, capture, and differential elastic-scattering experiments

High energy resolution measurement of the 238U neutron capture yield in the energy region between 1 and 100 keV

International Nuclear Information System (INIS)

Machlin, R.L.; Perez, R.B.; de Saussure, G.; Ingle, R.W.

1988-01-01

A measurement of the 238 U neutron capture yield was performed at the 150 meter flight-path of the ORELA facility on two 238 U samples (0.01224 and 0.0031 atomsbarn). The capture yeild data were normalized by Moxon's small resonance method. The energy resolution achieved in this measurement frequently resulted in doublet and triplet splittings of what appeared to be single resonance in previous measurements. This resolution should allow extension of the resolved resonance energy region in 238 U from the present 4-keV limit up to 15 or 20 keV incident neutron energy. Some 200 small resonances of the ( 238 U /plus/ n) compound nucleus have been observed which had not been detected in transmission measurement, in the energy range from 250 eV to 10 keV

Linear and mass attenuation coefficient for CdTe compound of X-rays from 10 to 100 keV energy range in different phases

Energy Technology Data Exchange (ETDEWEB)

Saim, A., E-mail: saim1989asma@gmail.com; Tebboune, A.; Berkok, H.; Belameiri, N.; Belbachir, A.H.

2014-07-25

The Full Potential Linear Muffin Tin Orbitals method within the density functional theory has been utilized to calculate structural and electronic properties of the CdTe compound. We have checked that the CdTe has two phase-transitions from zinc-blend to cinnabar and from cinnabar to rocksalt. We have found that the rigidity, the energy and the nature of the gap change according to the phase change, so we can predict that a CdTe detector may have different behaviors in different phase conditions. In order to investigate this behavior change, the linear and the mass attenuation coefficients of X-ray in rocksalt, zinc-blend and cinnabar structures are calculated from 10 keV to100 keV, using the XCOM data. We have found that when CdTe undergoes a phase transition from zinc-blend to cinnabar, its linear attenuation coefficient decreases down to a value of about 100 times smaller than its initial one, and when it undergoes a transition from cinnabar to rocksalt it increases up to a value about 90 times larger than its initial one.

On the 1285,0 keV; 55-184WW state structure

International Nuclear Information System (INIS)

Kupryashkin, V.T.; Muzalev, P.N.; Feoktistov, A.I.

1977-01-01

The structure of the 184 W (1285.0 keV; 5 - ) states is discussed. Decay of this level is shown schematically. The data on multiplicities and probabilities of the γ-transitions for the levels 1285.0 keV; 5 - of 184 W and 1621.4 keV; 5 - of 182 W are presented. The transition amplitude parameters are plotted for different probabilities B(E3;5 - → I + ). The relation between the collective transition amplitudes is established. Transition amplitude parameters and their collective and two-particle components, as well as impurity amplitudes of collective excitation wave functions and matrix elements are given

Isothermal annealing of silicon implanted with 50 keV 10B ions

International Nuclear Information System (INIS)

Weidner, B.; Zaschke, G.

1974-01-01

Isothermal annealing characteristics of silicon implanted with boron were measured and compared with calculated results. Implantation was performed with 50 keV 10 B ions in the dose range of 7.5 x 10 12 cm -2 to 2.0 x 10 15 cm -2 . Annealing temperatures ranged from 700 to 900 0 C. Maximum annealing time was 10 4 minutes. Annealing time strongly increases with increasing dose and decreasing temperature. Assuming that there is only one activation energy the isothermal annealing curves of constant dose and different temperatures were combined to a reduced annealing curve and the reduced isothermal annealing curve calculated. Starting from first order kinetics, considering the doping profile of boron in silicon and assuming a depth-dependent decay constant the experimentally determined annealing curves could be easily described over the total dose and time range

Attenuation coefficients of soils and some building materials of Bangladesh in the energy range 276-1332 keV

International Nuclear Information System (INIS)

Alam, M.N.; Miah, M.M.H.; Chowdhury, M.I.; Kamal, M.; Ghose, S.; Rahman, Runi

2001-01-01

The linear and mass attenuation coefficients of different types of soil, sand, building materials and heavy beach mineral samples from the Chittagong and Cox's Bazar area of Bangladesh were measured using a high-resolution HPGe detector and the γ-ray energies 276.1, 302.8, 356.0, 383.8, 661.6 and 1173.2 and 1332.5 keV emitted from point sources of 133 Ba, 137 Cs and 60 Co, respectively. The linear attenuation coefficients show a linear relationship with the corresponding densities of the samples studied. The variations of the mass attenuation coefficient with γ-ray energy were exponential in nature. The measured mass attenuation coefficient values were compared with measurements made in other countries for similar kinds of materials. The values are in good agreement with each other in most cases

Absolute measurement of the cross sections of neutron radiative capture for 23Na, Cr, 55Mn, Fe, Ni, 103Rh, Ta, 197Au and 238U in the 10-600keV energy range

International Nuclear Information System (INIS)

Le Rigoleur, Claude; Arnaud, Andre; Taste, Jean.

1976-10-01

The total energy weighting technique has been applied to measuring absolute neutron capture cross sections for 23 Na, Cr, 55 Mn, Fe, Ni, 103 Rh, Ta, 197 Au, 238 U in the 10-600keV energy range. A non hydrogeneous liquid scintillator was used to detect the gamma from the cascade. The neutron flux was measured with a 10 B INa(Tl) detector or a 6 Li glass scintillator of well known efficiency. The fast time-of-flight technique was used with on line digital computer data processing [fr

Mechanical design and construction of a 200 mA, 100 keV, DC, negative ion accelerator

International Nuclear Information System (INIS)

Purgalis, P.; Anderson, O.A.; Cooper, W.S.; Cummings, C.; Koehler, G.W.; Matuk, C.A.; Wells, R.P.

1987-01-01

A volume production source and a 100 keV, dc, accelerator together with an additional, modular, 100 keV, electro static focused accelerator provide a starting point for a high energy H - /D - beamline (200 keV to 800 keV), intended for fusion energy applications. The 100 keV accelerator tests started in June 1987. The mechanical design and construction of the accelerator is described

Scattering of light keV ions from amorphous and crystalline solid surfaces

International Nuclear Information System (INIS)

Robinson, J.E.; Kwok, K.K.; Thompson, D.A.

1976-01-01

Total reflection coefficients (R), backscattered energy fractions (γ), and backscattered energy spectra are evaluated using a binary collision Monte Carlo technique for a variety of light ions (H, D, T, He) in the energy range 0.25-8 keV, incident on amorphous targets (C, Fe, Nb). The scattering is also evaluated for H on Nb for a range of incident angles and two electronic stopping values. The average scattered energy per reflected particle and the backscattered energy spectra are found to vary in a universal manner as a function of the reflection coefficient between the Rutherford high energy limit and a low energy multiple collision limit. Single crystal effects are also briefly discussed using a diffusional dechanneling model. (Auth.)

Radiation vulcanization of natural rubber latex using 250 keV electron beam machine

Energy Technology Data Exchange (ETDEWEB)

Chirinos, H.; Yoshii, F.; Makuuchi, K.; Lugao, A. E-mail: ablugao@net.ipen.br

2003-08-01

The sensitized radiation vulcanization of natural rubber latex has been carried out with 250 keV electrons. Latex was irradiated over a range of the beam current from 5 to 20 mA in the presence of sensitizers like the n-butyl acrylate (n-BA). The vulcanization dose decreases with increasing beam current condition. The rate of vulcanization (R{sub vul}) depends on the beam current (I) as given by the equation R{sub vul}=kI{sup 0.6}.

A model for Simpson's 17 keV neutrino

International Nuclear Information System (INIS)

Rajpoot, S.

1992-01-01

Recent studies of β-decay spectra seem to confirm Simpson's earlier findings that the electron neutrinos contain a small (1%) admixture of a 17 keV Dirac neutrino. In this paper an unconventional model with SU(2) L x SU(2) R x U(1) B-1 gauge interactions is presented in which all neutrinos are Dirac particles. Electron and muon neutrinos acquire seesaw Dirac masses of order 10 -3 eV for the MSW solution for the solar neutrino problem. The τ neutrino is identified as Simpson's 17 keV neutrino. Constraints coming from cosmology and particle physics are shown to be satisfied

Direct elastic and inelastic processes produced in the case of He+-He for 3 KeV00

International Nuclear Information System (INIS)

Bordenave-Montesquieu, Daniele.

1980-12-01

The He + on He collision has been studied by the energy loss method in the 3 to 50 KeV energy range and 0.25 to 3 0 angle range. A detailed description of the experimental device, which has been built for this purpose, is made. Direct elastic and inelastic cross sections are then obtained by integration. A single theoretical model is given, which explains the main features of the elastic differential cross section behaviour [fr

Radiation blistering in Inconel-625 due to 100 KeV helium ion irradiation

International Nuclear Information System (INIS)

Whitton, J.L.; Rao, A.S.; Kaminsky, M.

1988-01-01

The objective of this study was to determine whether the change of angle of incidence of an ion beam impinging on surface blisters during their growth phase (before exfoliation) could influence the blister skin thickness and the blister crater depth. Polished, polycrystalline Inconel-625 samples were irradiated at room temperature and at normal incidence to the major sample surface with 100 keV helium ions to a total dose of 6.24x10 18 ions/cm 2 . The results revealed that many exfoliated blisters leave craters which have two or three concentric pits. The blister skin thickness near the center of the blister was found to agree well with the calculated projected range of 100 keV He ions in nickel. However, the blister skin thickness of some exfoliated blisters along the edge of the fracture surface showed different thicknesses. A model is proposed to explain the observed blister crater/blister fracture features in terms of a change of angle of incidence of the incident ions to the surface during the growth phase of surface blisters. (orig.)

A cryogenic electrostatic trap for long-time storage of keV ion beams

Science.gov (United States)

Lange, M.; Froese, M.; Menk, S.; Varju, J.; Bastert, R.; Blaum, K.; López-Urrutia, J. R. Crespo; Fellenberger, F.; Grieser, M.; von Hahn, R.; Heber, O.; Kühnel, K.-U.; Laux, F.; Orlov, D. A.; Rappaport, M. L.; Repnow, R.; Schröter, C. D.; Schwalm, D.; Shornikov, A.; Sieber, T.; Toker, Y.; Ullrich, J.; Wolf, A.; Zajfman, D.

2010-05-01

We report on the realization and operation of a fast ion beam trap of the linear electrostatic type employing liquid helium cooling to reach extremely low blackbody radiation temperature and residual gas density and, hence, long storage times of more than 5 min which are unprecedented for keV ion beams. Inside a beam pipe that can be cooled to temperatures <15 K, with 1.8 K reached in some locations, an ion beam pulse can be stored at kinetic energies of 2-20 keV between two electrostatic mirrors. Along with an overview of the cryogenic trap design, we present a measurement of the residual gas density inside the trap resulting in only 2×103 cm-3, which for a room temperature environment corresponds to a pressure in the 10-14 mbar range. The device, called the cryogenic trap for fast ion beams, is now being used to investigate molecules and clusters at low temperatures, but has also served as a design prototype for the cryogenic heavy-ion storage ring currently under construction at the Max-Planck Institute for Nuclear Physics.

Characteristic 8 keV X rays possess radiobiological properties of higher-LET radiation.

Science.gov (United States)

Shridhar, Ravi; Estabrook, William; Yudelev, Mark; Rakowski, Joseph; Burmeister, Jay; Wilson, George D; Joiner, Michael C

2010-03-01

Electronic brachytherapy systems are being developed that can deliver X rays of varying energy depending on the material of a secondary target. A copper target produces characteristic 8 keV X rays. Our aim was to determine whether 8 keV X rays might deliver greater biological effectiveness than megavoltage photons. Cells of the U251 human glioma cell line were used to compare the biological effects of 8 keV X rays and (60)Co gamma rays in terms of relative biological effectiveness (RBE), oxygen enhancement ratio (OER), and DNA damage. The RBE at 50% and 10% survival was 2.6 and 1.9, respectively. At 50% survival, the OER for cells treated with 8 keV X rays was 1.6 compared with 3.0 for (60)Co gamma rays. The numbers of H2AX foci per Gy after treatment with 8 keV X rays and (60)Co gamma rays were similar; however, the size of the foci generated at 8 keV was significantly larger, possibly indicating more complex DNA damage. The mean area of H2AX foci generated by 8 keV X rays was 0.785 microm(2) (95% CI: 0.756-0.814) compared with 0.491 microm(2) (95% CI: 0.462-0.520) for (60)Co gamma rays (P X rays produce two to three times the biological effectiveness of megavoltage photons, with a radiobiological profile similar to higher-LET radiations.

Range measurements of keV hydrogen ions in solid oxygen and carbon monoxide

International Nuclear Information System (INIS)

Schou, J.; Soerensen, H.; Andersen, H.H.; Nielsen, M.; Rune, J.

1984-01-01

Ranges of 1.3-3.5 keV/atom hydrogen and deuterium molecular ions have been measured by a thin-film reflection method. The technique, used here for range measurements in solid oxygen and carbon monoxide targets, is identical to the one used previously for range measurements in hydrogen and nitrogen. The main aim was to look for phase-effects, i.e. gas-solid differences in the stopping processes. While measured ranges in solid oxygen were in agreement with known gas data, the ranges in solid carbon monoxide were up to 50% larger than those calculated from gas-stopping data. The latter result agrees with that previously found for solid nitrogen. (orig.)

Changes in measured size of atherosclerotic plaque calcifications in dual-energy CT of ex vivo carotid endarterectomy specimens: effect of monochromatic keV image reconstructions

International Nuclear Information System (INIS)

Mannelli, Lorenzo; Mitsumori, Lee M.; Ferguson, Marina; Xu, Dongxiang; Chu, Baocheng; Branch, Kelley R.; Shuman, William P.; Yuan, Chun

2013-01-01

The aim of this study was to compare the size of the calcifications measured on the different keV images to a histological standard. Five ex vivo carotid endarterectomy (CEA) specimens were imaged with a dual-energy CT. CT images were reconstructed at different monochromatic spectral energies (40, 60, 77, 80, 100, 120, 140 keV). Cross-sectional area of the plaque calcifications present on each CT image was measured. The histological calcium areas on each corresponding CEA specimen were traced manually on digitised images of Toluidine Blue/Basic Fuchsin stained plastic sections. The CT images and corresponding histology sections were matched. The CT-derived calcium areas on each keV image were compared to the calcified area measurements by histology. A total of 107 histology sections were matched to corresponding CT images. The average calcified area per section by histology was 7.6 ± 7 mm 2 (range 0-26.4 mm 2 ). There was no significant difference between the calcified areas measured by histology and those measured on CT-virtual monochromatic spectral (VMS) reconstructed images at 77 keV (P = 0.08), 80 keV (P = 0.20) and 100 keV (P = 0.14). Calcium area measured on the 80 keV image set was most comparable to the amount of calcium measured by histology. (orig.)

Deactivation of group III acceptors in silicon during keV electron irradiation

International Nuclear Information System (INIS)

Sah, C.; Sun, J.Y.; Tzou, J.J.; Pan, S.C.

1983-01-01

Experimental results on p-Si metal-oxide-semiconductor capacitors (MOSC's) are presented which demonstrate the electrical deactivation of the acceptor dopant impurity during 8-keV electron irradiation not only in boron but also aluminum and indium-doped silicon. The deactivation rates of the acceptors during the 8-keV electron irradiation are nearly independent of the acceptor impurity type. The final density of the remaining active acceptor approaches nonzero values N/sub infinity/, with N/sub infinity/(B) Al--H>In-H. These deactivation results are consistent with our hydrogen bond model. The thermal annealing or regeneration rate of the deactivated acceptors in the MOSC's irradiated by 8-keV electron is much smaller than that in the MOSC's that have undergone avalanche electron injection, indicating that the keV electron irradiation gives rise to stronger hydrogen-acceptor bond

An experimental study of charge exchange process in the energy range 1-30 keV during the passage of alkali metal ions and atoms through cesium and potassium vapour

International Nuclear Information System (INIS)

Wittchow, F.

1979-01-01

An experimental study is presented of the charge exchange processes in the energy range of about 1-30 keV during the passage of positive alkali ions and alkali atoms through potassium and cesium vapour. The experimental set-up designed for this experiment includes a thermionic source for positive alkali ions with an acceleration stage, a first charge exchange cell to produce fast alkali atoms, a second charge exchange cell with a surface ionisation detector to determine the alkali metal vapor target thickness and a detection system with electrostatic bending of the charged secondary species. The maximum negative ion yield has been determined for the collision systems Li + + K, Na + + K, K + + K, and Rb + + K, and for another eleven systems the charge transfer cross-sections have been measured too. (orig./GG) [de

Neutron Fluence and Energy Reconstruction with the LNE-IRSN/MIMAC Recoil Detector MicroTPC at 27 keV

Energy Technology Data Exchange (ETDEWEB)

Maire, D.; Lebreton, L.; Querre, Ph. [Institute for Radioprotection and Nuclear Safety - IRSN, site of Cadarache, 13115 Saint Paul lez Durance (France); Bosson, G.; Guillaudin, O.; Muraz, J.F.; Riffard, Q.; Santos, D. [Laboratoire de Physique Subatomique et de Cosmologie - LPSCCNRSIN2P3/ UJF/INP, 38000 Grenoble (France)

2015-07-01

The French Institute for Radiation protection and Nuclear Safety (IRSN), designated by the French Metrology Institute (LNE) for neutron metrology, is developing a time projection chamber using a Micromegas anode: microTPC. This work is carried out in collaboration with the Laboratory of Subatomic Physics and Cosmology (LPSC). The aim is to characterize the energy distribution of neutron fluence in the energy range 8 keV - 5 MeV with a primary procedure. The time projection chambers are gaseous detectors able to measure charged particles energy and to reconstruct their track if a pixelated anode is used. In our case, the gas is used as a (n, p) converter in order to detect neutrons down to few keV. Coming from elastic collisions with neutrons, recoil protons lose a part of their kinetic energy by ionizing the gas. The ionization electrons are drifted toward a pixelated anode (2D projection), read at 50 MHz by a self-triggered electronic system to obtain the third track dimension. The neutron energy is reconstructed event by event thanks to proton scattering angle and proton energy measurements. The scattering angle is deduced from the 3D track. The proton energy is obtained by charge collection measurements, knowing the ionization quenching factor (i.e. the part of proton kinetic energy lost by ionizing the gas). The fluence is calculated thanks to the detected events number and the simulation of the detector response. The μTPC is a new reliable detector able to measure energy distribution of the neutron fluence without unfolding procedure or prior neutron calibration contrary to usual gaseous counters. The microTPC is still being developed and measurements have been carried out at the AMANDE facility, with neutrons energies going from 8 keV to 565 keV. After the context and the μ-TPC working principle presentation, measurements of the neutron energy and fluence at 27 keV and 144 keV are shown and compared to the complete detector response simulation. This work

7 keV sterile neutrino dark matter from split flavor mechanism

International Nuclear Information System (INIS)

Ishida, Hiroyuki; Takahashi, Fuminobu; Tokyo Univ., Kashiwa

2014-02-01

The recently discovered X-ray line at about 3.5 keV can be explained by sterile neutrino dark matter with mass, m s ≅ 7 keV, and the mixing, sin 2 2θ∝10 -10 . Such sterile neutrino is more long-lived than estimated based on the seesaw formula, which strongly suggests an extra flavor structure in the seesaw sector. We show that one can explain both the small mass and the longevity based on the split flavor mechanism where the breaking of flavor symmetry is tied to the breaking of the B-L symmetry. In a supersymmetric case we find that the 7 keV sterile neutrino implies the gravitino mass about 100 TeV.

Neutron resonance parameters of 96Zr below 100 keV

International Nuclear Information System (INIS)

Musgrove, A.R.D.

1977-08-01

Transmission data taken at the 80 m station of the Oak Ridge Electron Linear Accelerator have provided resonance parameters for 96 Zr to 100 keV. The average level spacing and neutron strength function for s-wave neutrons were as follows: = 8 +- 2 keV and S 0 = (0.21 +- 0.10) x 10 -4 . The average p-wave neutron strength function was S 1 = (7.4 +- 2.0) x 10 -4 . (Author)

Searching for the 3.5 keV Line in the Stacked Suzaku Observations of Galaxy Clusters

Science.gov (United States)

Bulbul, Esra; Markevitch, Maxim; Foster, Adam; Miller, Eric; Bautz, Mark; Lowenstein, Mike; Randall, Scott W.; Smith, Randall K.

2016-01-01

We perform a detailed study of the stacked Suzaku observations of 47 galaxy clusters, spanning a redshift range of 0.01-0.45, to search for the unidentified 3.5 keV line. This sample provides an independent test for the previously detected line. We detect a 2sigma-significant spectral feature at 3.5 keV in the spectrum of the full sample. When the sample is divided into two subsamples (cool-core and non-cool core clusters), the cool-core subsample shows no statistically significant positive residuals at the line energy. A very weak (approx. 2sigma confidence) spectral feature at 3.5 keV is permitted by the data from the non-cool-core clusters sample. The upper limit on a neutrino decay mixing angle of sin(sup 2)(2theta) = 6.1 x 10(exp -11) from the full Suzaku sample is consistent with the previous detections in the stacked XMM-Newton sample of galaxy clusters (which had a higher statistical sensitivity to faint lines), M31, and Galactic center, at a 90% confidence level. However, the constraint from the present sample, which does not include the Perseus cluster, is in tension with previously reported line flux observed in the core of the Perseus cluster with XMM-Newton and Suzaku.

Collision cross sections of N2 by H+ impact at keV energies within time-dependent density-functional theory

Science.gov (United States)

Yu, W.; Gao, C.-Z.; Zhang, Y.; Zhang, F. S.; Hutton, R.; Zou, Y.; Wei, B.

2018-03-01

We calculate electron capture and ionization cross sections of N2 impacted by the H+ projectile at keV energies. To this end, we employ the time-dependent density-functional theory coupled nonadiabatically to molecular dynamics. To avoid the explicit treatment of the complex density matrix in the calculation of cross sections, we propose an approximate method based on the assumption of constant ionization rate over the period of the projectile passing the absorbing boundary. Our results agree reasonably well with experimental data and semi-empirical results within the measurement uncertainties in the considered energy range. The discrepancies are mainly attributed to the inadequate description of exchange-correlation functional and the crude approximation for constant ionization rate. Although the present approach does not predict the experiments quantitatively for collision energies below 10 keV, it is still helpful to calculate total cross sections of ion-molecule collisions within a certain energy range.

The astrophysical S-factor for dd-reactions at keV-energy range

International Nuclear Information System (INIS)

Bystritskii, V.; Bystritsky, V.; Chaikovsky, S.

2001-01-01

The experimental results of measurements of the astrophysical S-factor for dd-reaction at keV-energy range collision energies using liner plasma technique are presented. The experiments were carried out at the high current generator of the Institute of High-Current Electronics in Tomsk, Russia. The measured values of the S-factors for the deuteron collision energies 1.80, 2.06 and 2.27 keV are S dd =(114±68), (64±30), (53±16) b x keV, respectively. The corresponding cross sections for dd-reactions, described as a product of the barrier factor and measured astrophysical S-factor, are σ dd n (E col =1.80 keV)=(4.3±2.6) x 10 -33 cm 2 ; σ dd n (E col =2.06 keV)=(9.8±4.6) x 10 -33 cm 2 ; σ dd n (E col =2.27 keV)=(2.1±0.6) x 10 -32 cm 2 . (orig.) [de

EMISSION LINES BETWEEN 1 AND 2 keV IN COMETARY X-RAY SPECTRA

Energy Technology Data Exchange (ETDEWEB)

Ewing, Ian; Christian, Damian J. [Department of Physics and Astronomy, California State University, 18111 Nordhoff Street, Northridge, CA 91330 (United States); Bodewits, Dennis [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Dennerl, Konrad [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, D-85741 Garching Germany (Germany); Lisse, Carey M. [Planetary Exploration Group, Space Department, Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723 (United States); Wolk, Scott J., E-mail: ian.ewing.794@my.csun.edu, E-mail: daman.christian@csun.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2013-01-20

We present the detection of new cometary X-ray emission lines in the 1.0-2.0 keV range using a sample of comets observed with the Chandra X-Ray Observatory and ACIS spectrometer. We have selected five comets from the Chandra sample with good signal-to-noise spectra. The surveyed comets are C/1999 S4 (LINEAR), C/1999 T1 (McNaught-Hartley), 153P/2002 (Ikeya-Zhang), 2P/2003 (Encke), and C/2008 8P (Tuttle). We modeled the spectra with an extended version of our solar wind charge exchange (SWCX) emission model. Above 1 keV, we find Ikeya-Zhang to have strong emission lines at 1340 and 1850 eV which we identify as being created by SWCX lines of Mg XI and Si XIII, respectively, and weaker emission lines at 1470, 1600, and 1950 eV formed by SWCX of Mg XII, Mg XI, and Si XIV, respectively. The Mg XI and XII and Si XIII and XIV lines are detected at a significant level for the other comets in our sample (LS4, MH, Encke, 8P), and these lines promise additional diagnostics to be included in SWCX models. The silicon lines in the 1700-2000 eV range are detected for all comets, but with the rising background and decreasing cometary emission, we caution that these detections need further confirmation with higher resolution instruments.

Effect of 200 keV Ar+ implantation on optical and electrical properties of polyethyleneterepthalate (PET)

International Nuclear Information System (INIS)

Kumar, Rajiv; Goyal, Meetika; Sharma, Ambika; Aggarwal, Sanjeev; Sharma, Annu; Kanjilal, D.

2015-01-01

In the present paper we have discussed the effect of 200 keV Ar + ions on the electrical and optical properties of PET samples. PET samples were implanted with 200 keV Ar + ions to various doses ranging from 1×10 15 to 1×10 17 Ar + cm 2 . The changes in the electrical and optical properties of pristine and implanted PET specimens have been studied by using Keithley electrometer and UV-Visible absorption spectroscopy. The electrical conductivity has found to be increased with increasing ion dose. The optical studies have revealed the drastic alterations in optical band gap from 3.63 eV to 1.48 eV and also increase in number of carbon atoms per cluster from 215 to 537. Further, the change in the electrical conductivity and optical band gap has also been correlated with the formation of conductive islands in the implanted layers of PET

7 keV sterile neutrino dark matter from split flavor mechanism

Energy Technology Data Exchange (ETDEWEB)

Ishida, Hiroyuki [Tohoku Univ., Sendai (Japan). Dept. of Physics; Jeong, Kwang Sik [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics; Tokyo Univ., Kashiwa (Japan). Kavli IPMU, TODIAS

2014-02-15

The recently discovered X-ray line at about 3.5 keV can be explained by sterile neutrino dark matter with mass, m{sub s}≅ 7 keV, and the mixing, sin{sup 2}2θ∝10{sup -10}. Such sterile neutrino is more long-lived than estimated based on the seesaw formula, which strongly suggests an extra flavor structure in the seesaw sector. We show that one can explain both the small mass and the longevity based on the split flavor mechanism where the breaking of flavor symmetry is tied to the breaking of the B-L symmetry. In a supersymmetric case we find that the 7 keV sterile neutrino implies the gravitino mass about 100 TeV.

Construction, calibration and test of an ionization chamber for exposure measurement of x and gamma radiation in region from 40 keV to 1250 keV

International Nuclear Information System (INIS)

Campos, C.A.A.L.

1982-01-01

An unsealed thimble ionization chamber with connecting cable was designed, manufactured and tested at the IRD=CNEN, for exposure or exposure rate measurement of X or gamma rays in the energy range from 40 KeV up to Cobalt-60. Recommendations given by IEC, TC-62 (1974) were used as acceptance tests of the ionization chamber for use as a tertiary standard (field class instruments) in radiation therapy. In addition, intercomparison with commercially available chambers of reference class type were carried out in respect to field size dependence, energy dependence, short and long term stability. The results of those tests indicated the usefulness of the developed ionization chamber as a tertiary standard. (author)

Characterization of the Metrology beamline at the SOLEIL synchrotron and application to the determination of mass attenuation coefficients of Ag and Sn in the range 3.5 ≤ E ≤ 28 keV

International Nuclear Information System (INIS)

Menesguen, Y.; Lepy, M.C.

2011-01-01

This work presents the new Metrology beamline at the SOLEIL synchrotron facility and a first attempt to quantitative measurements of mass attenuation coefficients for Ag and Sn performed on the hard X-ray branch. We first describe the beamline itself and the characterization performed of the unfocused monochromatic beam running mode. We performed a first experimental measurement of mass attenuation coefficients in the range 3.5 ≤ E ≤ 28 keV and we also derived the K-absorption and L-absorption jump ratios. The results are compared with theoretical values as well as with other experimental data and agree well with previous published values. (authors)

Study on the keV neutron capture reaction in {sup 56}Fe and {sup 57}Fe

Energy Technology Data Exchange (ETDEWEB)

Wang, Taofeng [Beihang University, International Research Center for Nuclei and Particles in the Cosmos, Beijing (China); Beihang University, School of Physics and Nuclear Energy Engineering, Beijing (China); Lee, Manwoo [Kyungpook National University, Department of Physics, Daegu (Korea, Republic of); Dong-nam Inst. of Radiological and Medical Sciences, Research Center, Busan (Korea, Republic of); Kim, Guinyun [Kyungpook National University, Department of Physics, Daegu (Korea, Republic of); Ro, Tae-Ik [Dong-A University, Department of Physics, Busan (Korea, Republic of); Kang, Yeong-Rok [Dong-A University, Department of Physics, Busan (Korea, Republic of); Dong-nam Inst. of Radiological and Medical Sciences, Research Center, Busan (Korea, Republic of); Igashira, Masayuki; Katabuchi, Tatsuya [Tokyo Institute of Technology, Research Laboratory for Nuclear Reactors, Tokyo (Japan)

2014-03-15

The neutron capture cross-sections and the radiative capture gamma-ray spectra from the broad resonances of {sup 56}Fe and {sup 57}Fe in the neutron energy range from 10 to 90 keV and 550 keV have been measured with an anti-Compton NaI(Tl) detector. Pulsed keV neutrons were produced from the {sup 7}Li (p,n) {sup 7}Be reaction by bombarding the lithium target with the 1.5ns bunched proton beam from the 3MV Pelletron accelerator. The incident neutron spectrum on a capture sample was measured by means of a time-of-flight (TOF) method with a {sup 6}Li -glass detector. The number of weighted capture counts of the iron or gold sample was obtained by applying a pulse height weighting technique to the corresponding capture gamma-ray pulse height spectrum. The neutron capture gamma-ray spectra were obtained by unfolding the observed capture gamma-ray pulse height spectra. To achieve further understanding on the mechanism of neutron radiative capture reaction and study on physics models, theoretical calculations of the γ-ray spectra for {sup 56}Fe and {sup 57}Fe with the POD program have been performed by applying the Hauser-Feshbach statistical model. The dominant ingredients to perform the statistical calculation were the Optical Model Potential (OMP), the level densities described by the Mengoni-Nakajima approach, and the γ-ray transmission coefficients described by γ-ray strength functions. The comparison of the theoretical calculations, performed only for the 550keV point, show a good agreement with the present experimental results. (orig.)

Study of fission product γ spectra in the band 2-500 keV

International Nuclear Information System (INIS)

Rousseau, A.

1959-01-01

In the study of the γ spectrum of uranium fission products, particular attention has been given in this note to the part of the spectrum ranging between 0 and 500 keV after a given pile operating programme and the evolution of this spectrum with time after a pile shutdown has been followed. The study be related to the fission products which appear in the pile as a whole or on those produced in a uranium sample assumed to have been placed in the pile. The latter case has been envisaged here. The spectrum determination is based partly on theory and partly on experiment. The pile operating conditions are different in the two cases, which widens the range of validity of the spectra traced here. (author) [fr

Beam Spot Measurement on a 400 keV Electron Accelerator

DEFF Research Database (Denmark)

Miller, Arne

1979-01-01

A line probe is used to measure the beam spot radius and beam divergence at a 400 keV ICT electron accelerator, and a method is shown for reducing the line probe data in order to get the radial function.......A line probe is used to measure the beam spot radius and beam divergence at a 400 keV ICT electron accelerator, and a method is shown for reducing the line probe data in order to get the radial function....

Study of fission product {gamma} spectra in the band 2-500 keV; Etude du spectre {gamma} des produits de fission dans la bande 0-500 keV

Energy Technology Data Exchange (ETDEWEB)

Rousseau, A. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

In the study of the {gamma} spectrum of uranium fission products, particular attention has been given in this note to the part of the spectrum ranging between 0 and 500 keV after a given pile operating programme and the evolution of this spectrum with time after a pile shutdown has been followed. The study be related to the fission products which appear in the pile as a whole or on those produced in a uranium sample assumed to have been placed in the pile. The latter case has been envisaged here. The spectrum determination is based partly on theory and partly on experiment. The pile operating conditions are different in the two cases, which widens the range of validity of the spectra traced here. (author) [French] Dans l'etude du spectre {gamma} des produits de fission de l'uranium, on s'est plus particulierement interesse dans la presente note a determiner la partie du spectre qui s'etend entre 0 et 500 keV, au bout d'un fonctionnement donne de pile, et a suivre l'evolution de ce spectre dans le temps apres un arret de pile. L'etude peut porter sur les produits de fission apparus dans toute la pile ou sur ceux apparus dans un echantillon d'uranium suppose place en pile. C'est ce dernier cas que nous avons envisage. La determination du spectre s'appuie sur une partie theorique et sur une partie experimentale. Les fonctionnements de pile choisis sont differents dans les deux cas, ce qui permet d'etendre la gamme de validite des spectres traces ici. (auteur)

Study of fission product {gamma} spectra in the band 2-500 keV; Etude du spectre {gamma} des produits de fission dans la bande 0-500 keV

Energy Technology Data Exchange (ETDEWEB)

Rousseau, A [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

In the study of the {gamma} spectrum of uranium fission products, particular attention has been given in this note to the part of the spectrum ranging between 0 and 500 keV after a given pile operating programme and the evolution of this spectrum with time after a pile shutdown has been followed. The study be related to the fission products which appear in the pile as a whole or on those produced in a uranium sample assumed to have been placed in the pile. The latter case has been envisaged here. The spectrum determination is based partly on theory and partly on experiment. The pile operating conditions are different in the two cases, which widens the range of validity of the spectra traced here. (author) [French] Dans l'etude du spectre {gamma} des produits de fission de l'uranium, on s'est plus particulierement interesse dans la presente note a determiner la partie du spectre qui s'etend entre 0 et 500 keV, au bout d'un fonctionnement donne de pile, et a suivre l'evolution de ce spectre dans le temps apres un arret de pile. L'etude peut porter sur les produits de fission apparus dans toute la pile ou sur ceux apparus dans un echantillon d'uranium suppose place en pile. C'est ce dernier cas que nous avons envisage. La determination du spectre s'appuie sur une partie theorique et sur une partie experimentale. Les fonctionnements de pile choisis sont differents dans les deux cas, ce qui permet d'etendre la gamme de validite des spectres traces ici. (auteur)

Reduction of transient diffusion from 1 endash 5 keV Si+ ion implantation due to surface annihilation of interstitials

International Nuclear Information System (INIS)

Agarwal, A.; Gossmann, H.-.; Eaglesham, D.J.; Pelaz, L.; Jacobson, D.C.; Haynes, T.E.; Erokhin, Y.E.

1997-01-01

The reduction of transient enhanced diffusion (TED) with reduced implantation energy has been investigated and quantified. A fixed dose of 1x10 14 cm -2 Si + was implanted at energies ranging from 0.5 to 20 keV into boron doping superlattices and enhanced diffusion of the buried boron marker layers was measured for anneals at 810, 950, and 1050 degree C. A linearly decreasing dependence of diffusivity enhancement on decreasing Si + ion range is observed at all temperatures, extrapolating to ∼1 for 0 keV. This is consistent with our expectation that at zero implantation energy there would be no excess interstitials from the implantation and hence no TED. Monte Carlo modeling and continuum simulations are used to fit the experimental data. The results are consistent with a surface recombination length for interstitials of <10 nm. The data presented here demonstrate that in the range of annealing temperatures of interest for p-n junction formation, TED is reduced at smaller ion implantation energies and that this is due to increased interstitial annihilation at the surface. copyright 1997 American Institute of Physics

Power supply for the LBL 40 keV neutral beam source

International Nuclear Information System (INIS)

Baker, W.R.; Fitzgerald, M.L.; Honey, V.J.

1975-11-01

A 20 keV, 50 Amp, 10 millisec pulse D 0 Neutral Beam Source at the Lawrence Berkeley Laboratory that serves as the prototype for 12 similar sources now in operation on the 2XIIB Mirror Machine at the Lawrence Livermore Laboratory has been recently upgraded to operate at 40 keV. The system of electronically regulated and controlled power supplies that drive the Source is described

A cryogenic electrostatic trap for long-time storage of keV ion beams.

Science.gov (United States)

Lange, M; Froese, M; Menk, S; Varju, J; Bastert, R; Blaum, K; López-Urrutia, J R Crespo; Fellenberger, F; Grieser, M; von Hahn, R; Heber, O; Kühnel, K-U; Laux, F; Orlov, D A; Rappaport, M L; Repnow, R; Schröter, C D; Schwalm, D; Shornikov, A; Sieber, T; Toker, Y; Ullrich, J; Wolf, A; Zajfman, D

2010-05-01

We report on the realization and operation of a fast ion beam trap of the linear electrostatic type employing liquid helium cooling to reach extremely low blackbody radiation temperature and residual gas density and, hence, long storage times of more than 5 min which are unprecedented for keV ion beams. Inside a beam pipe that can be cooled to temperatures <15 K, with 1.8 K reached in some locations, an ion beam pulse can be stored at kinetic energies of 2-20 keV between two electrostatic mirrors. Along with an overview of the cryogenic trap design, we present a measurement of the residual gas density inside the trap resulting in only 2 x 10(3) cm(-3), which for a room temperature environment corresponds to a pressure in the 10(-14) mbar range. The device, called the cryogenic trap for fast ion beams, is now being used to investigate molecules and clusters at low temperatures, but has also served as a design prototype for the cryogenic heavy-ion storage ring currently under construction at the Max-Planck Institute for Nuclear Physics.

The repetitive flaking of Inconel 625 by 100 keV helium bombardment

International Nuclear Information System (INIS)

Whitton, J.L.; Chen, H.M.; Littmark, U.

1981-01-01

Repetitive flaking of Inconel 625 occurs with ion bombardment doses of > than 10 18 100 keV helium ions cm -2 , with up to 39 exfoliations being observed after bombardment with 3 x 10 19 ions cm -2 . The thickness of the flakes, measured by scanning electron microscopy, is some 30% greater than when measured by Rutherford backscattering (RBS) of 1.8 MeV helium ions. These RBS measurements compare well with the thickness of the remaining layers in the resultant craters and to the most probable range of the 100 keV helium. The area of the flakes is dictated by the grain boundaries, and when one flake is ejected, the adjacent grains are prevented from doing so since there now exists an escape route for the injected helium. A strong dose rate dependence is observed; decreasing the beam current from 640 μA cm -2 to 64 μA cm -2 results in a factor 20 fewer flakes being exfoliated (for the same total dose of 3 x 10 19 ions cm -2 ). Successive flakes decrease in area, suggesting that eventually a cratered, but stable, surface will result with the only erosion being by the much less effective mechanism of sputtering. (orig.)

Compton scattering of 145 keV photons from bound electrons of tin and molybdenum

Energy Technology Data Exchange (ETDEWEB)

Ghumman, B S; Acharya, V B; Singh, B [Punjabi Univ., Patiala (India). Dept. of Physics

1981-10-28

Differential cross sections for Compton scattering of 145 keV gamma rays from K-shell electrons of tin and molybdenum are measured at scattering angles in the range 30 to 150/sup 0/. Measurements are made employing NaI(Tl) detectors and a coincidence set up with resolving time approximately equal to 30 ns. The experimental results are compared with the available theoretical data. The total cross section is estimated to be about 0.43 sigmasub(F) for tin and 0.41 sigmasub(F) for molybdenum.

INTERBALL-Auroral observations of 0.1-12 keV ion gaps in the diffuse auroral zone

Directory of Open Access Journals (Sweden)

R. A. Kovrazhkin

1999-06-01

Full Text Available We examine ion flux dropouts detected by INTERBALL-Auroral upon traversal of the auroral zone at altitudes of \\sim13 000 up to 20 000 km. These dropouts which we refer to as "gaps", are frequently observed irrespectively of longitudinal sector and appear characteristic of INTERBALL-Auroral ion spectrograms. Whereas some of these gaps display a nearly monoenergetic character (~12 keV, others occur at energies of a few hundreds of eV up to several keV. INTERBALL-Auroral data exhibit the former monoenergetic gap variety essentially in the evening sector. As examined in previous studies, these gaps appear related to transition from particle orbits that are connected with the magnetotail plasma source to closed orbits encircling the Earth. The latter gap variety, which spreads over several hundreds of eV to a few keV is often observed in the dayside magnetosphere. It is argued that such gaps are due to magnetospheric residence times well above the ion lifetime. This interpretation is supported by numerical orbit calculations which reveal extremely large (up to several tens of hours times of flight in a limited energy range as a result of conflicting E × B and gradient-curvature drifts. The characteristic energies obtained numerically depend upon both longitude and latitude and are quite consistent with those measured in-situ.Key words. Magnetospheric physics (auroral phenomena; plasma convection

Design and fabrication of a Transverse Field Focussing (TFF) 180 keV negative ion accelerator

International Nuclear Information System (INIS)

Matuk, C.A.; Anderson, O.A.; Owren, H.M.; Paterson, J.A.; Purgalis, P.

1985-11-01

The 180 keV Transverse Field Focussing (TFF) negative ion accelerator described is the final component of a negative ion based neutral beam acceleration system which is being developed as proof-of-principle demonstration of a radiation hardened neutral beamline. The 180 keV beamline consists of: a surface conversion negative ion source, a 80 keV pre-accelerator, a TFF pumping, matching, and transport section, and the 180 keV TFF accelerator presented. This beamline is expected to provide 1 A of H - at 180 keV. In the design of the accelerator, particular importance was given to the rigidity of the accelerator electrode mounting structures and to the electrical isolation of the electrodes along with their related cooling lines. An optical alignment scheme was developed to assemble and to insure precision alignment of the electrodes

The NuSTAR Serendipitous Survey: Hunting for the Most Extreme Obscured AGN at >10 keV

Science.gov (United States)

Lansbury, G. B.; Alexander, D. M.; Aird, J.; Gandhi, P.; Stern, D.; Koss, M.; Lamperti, I.; Ajello, M.; Annuar, A.; Assef, R. J.; Ballantyne, D. R.; Baloković, M.; Bauer, F. E.; Brandt, W. N.; Brightman, M.; Chen, C.-T. J.; Civano, F.; Comastri, A.; Del Moro, A.; Fuentes, C.; Harrison, F. A.; Marchesi, S.; Masini, A.; Mullaney, J. R.; Ricci, C.; Saez, C.; Tomsick, J. A.; Treister, E.; Walton, D. J.; Zappacosta, L.

2017-09-01

We identify sources with extremely hard X-ray spectra (I.e., with photon indices of {{Γ }}≲ 0.6) in the 13 deg2 NuSTAR serendipitous survey, to search for the most highly obscured active galactic nuclei (AGNs) detected at > 10 {keV}. Eight extreme NuSTAR sources are identified, and we use the NuSTAR data in combination with lower-energy X-ray observations (from Chandra, Swift XRT, and XMM-Newton) to characterize the broadband (0.5-24 keV) X-ray spectra. We find that all of the extreme sources are highly obscured AGNs, including three robust Compton-thick (CT; {N}{{H}}> 1.5× {10}24 cm-2) AGNs at low redshift (z< 0.1) and a likely CT AGN at higher redshift (z = 0.16). Most of the extreme sources would not have been identified as highly obscured based on the low-energy (< 10 keV) X-ray coverage alone. The multiwavelength properties (e.g., optical spectra and X-ray-mid-IR luminosity ratios) provide further support for the eight sources being significantly obscured. Correcting for absorption, the intrinsic rest-frame 10-40 keV luminosities of the extreme sources cover a broad range, from ≈ 5× {10}42 to 1045 erg s-1. The estimated number counts of CT AGNs in the NuSTAR serendipitous survey are in broad agreement with model expectations based on previous X-ray surveys, except for the lowest redshifts (z< 0.07), where we measure a high CT fraction of {f}{CT}{obs}={30}-12+16 % . For the small sample of CT AGNs, we find a high fraction of galaxy major mergers (50% ± 33%) compared to control samples of “normal” AGNs.

New determinations of gamma-ray line intensities of the E{sub p}=550 and 1747 keV resonances of the {sup 13}C(p,{gamma}){sup 14}N reaction

Energy Technology Data Exchange (ETDEWEB)

Kiener, J. E-mail: kiener@csnsm.in2p3.fr; Gros, M.; Tatischeff, V.; Attie, D.; Bailly, I.; Bauchet, A.; Chapuis, C.; Cordier, B.; Deloncle, I.; Porquet, M.G.; Schanne, S.; Sereville, N. de; Tauzin, G

2004-03-01

Gamma-ray angular distributions for the resonances at E{sub p}=550 and 1747 keV of the radiative capture reaction {sup 13}C(p,{gamma}){sup 14}N have been measured, using intense proton beams on isotopically pure {sup 13}C targets. Experimental gamma-ray spectra were obtained with three HP-Germanium detectors at four angles for E{sub p}=550 keV and six angles for E{sub p}=1747 keV in the range of 0-90 deg. with respect to the proton beam. From the data, relative intensities for the strongest transitions were extracted with an accuracy of typically 5%, making these resonances new useful gamma-ray standards for efficiency calibration in the energy range from E{sub {gamma}}=1.6-9 MeV. Gamma-ray branching ratios were obtained for several levels of {sup 14}N and are compared with literature values.

Determination of personnel exposures in the lower energy ranges of X-ray by photographic dosimeter

International Nuclear Information System (INIS)

Ha, C.W.; Kim, J.R.; Suk, K.W.

1986-01-01

This paper described an improved technical method required for proper evaluation of personnel exposures by means of the photographic dosimeter developed by KAERI in lower gamma or X-ray energy regions, with which response of the dosimeter varies significantly. With calibration of the dosimeter in the energy range from 30 to 300 keV, the beam spectrum was carefully selected and specified it adequately. The absorber combinations and absorber thickness used to obtain the specified X-ray spectra from a constant potential X-ray machine were determined theoretically and also experimentally. A correlation between the density and exposure for the four separate energies, such as 49 keV eff , 154 keV eff 250 keV eff and 662 keV, is experimentally determined. As a result, it can be directly evaluated the exposure from the measured response of dosimeter. (Author)

A Study of the 190 keV Transition in {sup 141}La

Energy Technology Data Exchange (ETDEWEB)

Berg, V; Hoeglund, Aa [Inst. of Physics, Univ. of Stockholm (Sweden); [AB Atome nergi, Nykoping (Sweden); Fogelberg, B [Inst. of Physics, Uppsala Univ. (Sweden)

1970-05-15

The gamma-ray spectrum from the decay of 18 min 141 Ba has been studied. Seventeen transitions were found below 900 keV, with energies and (intensities) as follows: 112.9{+-}0.2(3.0), 163.1{+-}0.3 (1.0), 165.7{+-}0.4(0.7), 180.5{+-}0.2(0.9), 190.3{+-}0.1(100), 276.9{+-}0.1 (52.2), 304.2{+-}0.1(55.8), 343.6{+-}0.1(30.8), 364.4{+-}0.6(1.6), 389.7{+-}0.2(2.8), 457.7{+-}0.2(10.4), 462.3{+-}0.2(10.5), 467.3{+-}0.1(11.4), 625.1{+-}0.2(6.1), 647.9{+-}0.2(10.7), 739.1{+-}0.3(8.7), 876.5{+-}0.3(6.7). K- and L-shell conversion coefficients have been measured for the 190. 3 keV transition, yielding a multipolarity of M1 + < 8 % E2. Half-life measurements using delayed coincidence technique have given the following results: T{sub 1/2} (190 keV level) = 1.27 {sup +0.06}{sub -0.10} ns, T{sub 1/2} (304 keV level) < 200 ps, T{sub 1/2} (467 keV level) < 120 ps. A level scheme of {sup 141}La has been constructed, and the spin-parity assignments of the ground state and first excited state are discussed in terms of the shell model.

Electron response of some low-Z scintillators in wide energy range

International Nuclear Information System (INIS)

Swiderski, L; Marcinkowski, R; Moszynski, M; Czarnacki, W; Szawlowski, M; Szczesniak, T; Pausch, G; Plettner, C; Roemer, K

2012-01-01

Light yield nonproportionality and the intrinsic resolution of some low atomic number scintillators were studied by means of the Wide Angle Compton Coincidence (WACC) technique. The plastic and liquid scintillator response to Compton electrons was measured in the energy range of 10 keV up to 4 MeV, whereas a CaF 2 :Eu sample was scanned from 3 keV up to 1 MeV. The nonproportionality of the CaF 2 :Eu light yield has characteristics typical for inorganic scintillators of the multivalent halides group, whereas tested organic scintillators show steeply increasing nonproportionality without saturation point. This is in contrast to the behavior of all known inorganic scintillators having their nonproportionality curves at saturation above energies between tens and several hundred keV.

Electron response of some low-Z scintillators in wide energy range

Science.gov (United States)

Swiderski, L.; Marcinkowski, R.; Moszynski, M.; Czarnacki, W.; Szawlowski, M.; Szczesniak, T.; Pausch, G.; Plettner, C.; Roemer, K.

2012-06-01

Light yield nonproportionality and the intrinsic resolution of some low atomic number scintillators were studied by means of the Wide Angle Compton Coincidence (WACC) technique. The plastic and liquid scintillator response to Compton electrons was measured in the energy range of 10 keV up to 4 MeV, whereas a CaF2:Eu sample was scanned from 3 keV up to 1 MeV. The nonproportionality of the CaF2:Eu light yield has characteristics typical for inorganic scintillators of the multivalent halides group, whereas tested organic scintillators show steeply increasing nonproportionality without saturation point. This is in contrast to the behavior of all known inorganic scintillators having their nonproportionality curves at saturation above energies between tens and several hundred keV.

Searches for 3.5 keV Absorption Features in Cluster AGN Spectra

Science.gov (United States)

Conlon, Joseph P.

2018-06-01

We investigate possible evidence for a spectral dip around 3.5 keV in central cluster AGNs, motivated by previous results for archival Chandra observations of the Perseus cluster and the general interest in novel spectral features around 3.5 keV that may arise from dark matter physics. We use two deep Chandra observations of the Perseus and Virgo clusters that have recently been made public. In both cases, mild improvements in the fit (Δχ2 = 4.2 and Δχ2 = 2.5) are found by including such a dip at 3.5 keV into the spectrum. A comparable result (Δχ2 = 6.5) is found re-analysing archival on-axis Chandra ACIS-S observations of the centre of the Perseus cluster.

H(2s) excitation in 10-100 keV H+ - H collisions

International Nuclear Information System (INIS)

Higgins, D.P.; Geddes, J.; Gilbody, H.B.

1996-01-01

The authors have used a crossed beam technique to determine cross sections for 2s excitation of H atoms in 10-100 keV collisions. The results extend their previous 4-26 keV measurements to intermediate energies where theoretical predictions based on close coupling methods are known to be strongly dependent on the choice of the expansion basis. The 4-100 keV cross sections exhibit an undulatory structure similar to that predicted by some of the many close coupling calculations but good quantitative agreement is shown to be very limited. Close coupling calculations which employ large basis sets at the expense of target states are shown to agree less satisfactorily with experiment than those which include only the dominant 1s capture channel

A Study of the 384 KeV Complex Gamma Emission from Plutonium-239

International Nuclear Information System (INIS)

Forsyth, R.S.; Ronqvist, N.

1965-11-01

Plutonium-239 has been reported to emit a gamma of energy 384 KeV. Subsequent workers, using radiation of this energy as a nondestructive measure of the plutonium content of various materials, found that the peak obtained by sodium iodide scintillation spectrometry showed a pronounced shoulder at about 330 KeV. This shoulder has been attributed to protactinium-233 and to uranium-237. From the width of the peak, however, it is obvious that at least three contributors are present. The present paper describes gamma spectrometric studies of plutonium samples of several isotopic compositions using a sodium iodide detector and a lithium-drifted germanium detector. The 384 KeV peak has been shown to be a complex peak containing 12 gamma components due to plutonium-239 between 300 - 450 KeV, and their relative intensities have been estimated. Anion exchange and solvent extraction experiments have also demonstrated that two further contributions due to uranium-237 are present in plutonium containing significant amounts of plutonium-241

A Study of the 384 KeV Complex Gamma Emission from Plutonium-239

Energy Technology Data Exchange (ETDEWEB)

Forsyth, R S; Ronqvist, N

1965-11-15

Plutonium-239 has been reported to emit a gamma of energy 384 KeV. Subsequent workers, using radiation of this energy as a nondestructive measure of the plutonium content of various materials, found that the peak obtained by sodium iodide scintillation spectrometry showed a pronounced shoulder at about 330 KeV. This shoulder has been attributed to protactinium-233 and to uranium-237. From the width of the peak, however, it is obvious that at least three contributors are present. The present paper describes gamma spectrometric studies of plutonium samples of several isotopic compositions using a sodium iodide detector and a lithium-drifted germanium detector. The 384 KeV peak has been shown to be a complex peak containing 12 gamma components due to plutonium-239 between 300 - 450 KeV, and their relative intensities have been estimated. Anion exchange and solvent extraction experiments have also demonstrated that two further contributions due to uranium-237 are present in plutonium containing significant amounts of plutonium-241.

Experiments on secondary ion emission with multicharged keV ion bombardement

International Nuclear Information System (INIS)

Della Negra, S.; Depauw, J.; Joret, H.; Le Beyec, Y.; Schweikert, E.A.

1987-01-01

An electron cyclotron resonance ion source was used to study the influence of the incident charge state of keV ions on secondary ion emission. The experiments were run with 18 keV Arn+ (1 < n < 11) beams produced by a minimafios source. Various types of targets were bombarded by the ion beam and the sputtered ionized species were identified by time of flight mass spectrometry. The experimental arrangement is detailed and preliminary results are indicated

Recent photoabsorption measurements in the rare gases and alkalis in the 3 to 15 keV photon energy region

International Nuclear Information System (INIS)

Berry, H.G.

1994-01-01

The attenuation cross-section of photons in helium in the range 3 to 14 keV has been measured. The results indicate the importance of Compton scattering in this range and show reasonable agreement with theory. The authors have also used a heat-pipe to measure absorption spectra in argon, potassium and rubidium near their respective K-edges and have made identifications using relativistic Hartree-Fock calculations. Some ion spectra near and below the K-edges of argon and potassium are also presented

Measurement of angular dependence of M X-ray production cross-sections in Re, Bi and U at 5.96 keV

International Nuclear Information System (INIS)

Apaydin, G.; Tirasoglu, E.; Sogut, O.

2008-01-01

The M X-ray production differential cross sections in Re, Bi and U elements have been measured at the 5.96 keV incident photon energy in an angular range 135 - 155 degrees. The measurements were performed using a Fe 55 source and a Si(Li) detector. It appears that, after photoionization of inner shells, the vacancy state has equal population of magnetic substates and the subsequent X-ray emission is isotropic. Total M X-ray production cross sections from the decay at the 5.96 keV photon energies are found to be in good agreement with the calculated theoretical results using the theoretical values of M shell photoionization cross section. (authors)

Investigation of the 14N/d,α/12C reaction at Esub(d)=640-310 keV deuteron energies

International Nuclear Information System (INIS)

Bakr, M.H.S.; Hunyadi, I.; Schlenk, G.; Somogyi, G.; Valek, A.

1974-01-01

Angular distributions of the α 0 , α 1 , α 2 , and α 3 groups from the 14 N/d,α/ 12 C reaction have been measured at deuteron energies 640, 510, and 350 keV using solid state track detectors. Semiconductor detector was used to measure the excitation functions of the α 0 and α 1 groups from the same reaction in the energy range 640-310 keV at THETAsub(lab)=90 0 . The absolute cross-section values are given for the alpha groups investigated. The experimentally obtained angular distributions have been analysed in terms of Legendre polynomials. The measured relative intensity ratios of the α 0 , α 1 , and α 3 groups could be reproduced by a simple calculation assuming statistical compound reaction mechanism. (B.T.)

Correlation between blister skin thickness, the maximum in the damage-energy distribution, and projected ranges of He+ ions in metals: V

International Nuclear Information System (INIS)

Kaminsky, M.; Das, S.K.; Fenske, G.

1976-01-01

In these experiments a systematic study of the correlation of the skin thickness measured directly by scanning electron microscopy with both the calculated projected-range values and the maximum in the damage-energy distribution has been conducted for a broad helium-ion energy range (100 keV-1000 keV in polycrystalline vanadium. (Auth.)

Incoherent scattering of gamma rays by K-shell electrons. [Differential cross sections, 145 to 662 KeV

Energy Technology Data Exchange (ETDEWEB)

Spitale, G.C.; Bloom, S.D.

1976-05-12

Differential cross sections for incoherent scattering by K-shell electrons were measured, using coincidence techniques, for incident photons having energies of 662 keV, 320 keV, and 145 keV. The spectral distributions of the scattered photons emerging at scattering angles from 20/sup 0/ to about 140/sup 0/ are reported. Target materials were iron, tin, holmium, and gold at 320 keV; tin and gold at 662 keV; and iron and tin at 145 keV. A typical energy spectrum consists of a scattered peak that is much narrower than would be expected from the bound state electron motion. The peak also, typically, reaches a broad maximum width for scattering angles between 45/sup 0/ and 60/sup 0/. Rather than monotonically increasing with atomic number the peak width reaches a broad maximum, generally, between Z = 50 and Z = 67, and then decreases with increasing atomic number. No Compton defect appears in any of the peaks to within +- 20 keV. A discussion of the expected magnitude of the Compton defect is included. The peak is superimposed on a continuum that diverges at the low end of the scattered photon spectrum for the following cases: gold, holmium, and tin targets for 320-keV incident photons; gold and possibly tin targets for 662-keV photons incident. This infrared divergence is expected on theoretical grounds and has been predicted. It is very nearly isotropic.

Differences in the neutralization of 2.4--10 keV Ne+ scattered from the Cu and Au atoms of an alloy surface

International Nuclear Information System (INIS)

Buck, T.M.; Wallace, W.E.; Baragiola, R.A.; Wheatley, G.H.; Rothman, J.B.; Gorte, R.J.; Tittensor, J.G.

1993-01-01

The neutralization behavior of low-energy Ne + ions scattered from a compositionally ordered Cu 3 Au(100) surface has been studied over a range of incident energy E 0 from 2.4 to 10 keV. Ion fractions of Ne scattered from Cu atoms in the first, or first two, atom layers exhibited a sharp increase setting in at an E 0 of 4--5 keV, reaching 70% at 10 keV for first-layer scattering. Inelastic energy losses, up to 130 eV, and Auger electron emission from Ne scattered from Cu, were also observed at incident energies above 4 keV. Ne scattered from the Au atoms on the same Cu 3 Au(100) surface showed only the usual velocity-dependent Auger and resonance neutralization. An explanation of the Cu results is given in terms of Ne 2s vacancy creation during the close collision of Ne, which is neutralized on the inward path, followed by autoionization on the outward path after scattering into the vacuum. Conversely, Ne cannot approach Au closely enough to form an appropriate inner-shell vacancy. This is due to the higher Coulombic repulsion created by the greater charge of the Au nucleus

Construction of an electron accelerator of 20 KeV: application in the polymeric study

International Nuclear Information System (INIS)

Sandonato, G.M.

1983-01-01

A low energy electron accelerator (maximum energy 20 KeV) is constructed. A black and white kinescope electron gun, with a single thermionic emitter was used as electron source. The energy of electron beam can be changed continuously from 0 to 20 KeV. The intensity of the current can be changed from a minimum of 10 -12 A to a maximum of 3 μA, and can be mantained contant in time after its value has been fixed. The irradiated area can be changed from a diameter of 1 milimeter to a maximum of 6 centimeter, by focalizing or defocalizing the image of electron beam. The final pressure reached in vacuum chambers was 10 -7 Torr. During operation the surface of cathode of electron gun is damaged by ion bombardeament. The degree of damage can be checked if the cathode image is focalized and examined on a luminescent screen. The accelerator was used to study electron irradiation effects in Teflon, employing the method of the split Faraday cup. Transient charging and discharging currents were measured. The average range of electrons of the electrons and the induced conductivity were determined. (Author) [pt

Experimental studies of keV energy neutron-induced reactions relevant to astrophysics and nuclear physics

Energy Technology Data Exchange (ETDEWEB)

Shima, T.; Kii, T.; Kikuchi, T.; Okazaki, F.; Kobayashi, T.; Baba, T.; Nagai, Y. [Tokyo Inst. of Tech. (Japan). Faculty of Science; Igashira, M.

1997-03-01

Nuclear reactions induced by keV energy neutrons provide a plenty of informations for studies of both astrophysics and nuclear physics. In this paper we will show our experimental studies of neutron- induced reactions of light nuclei in the keV energy region by means of a pulsed keV neutron beam and high-sensitivity detectors. Also we will discuss astrophysical and nuclear-physical consequences by using the obtained results. (author)

NEW OBSERVATIONS OF THE SOLAR 0.5–5 KEV SOFT X-RAY SPECTRUM

Energy Technology Data Exchange (ETDEWEB)

Caspi, Amir; Woods, Thomas N. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States); Warren, Harry P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2015-03-20

The solar corona is orders of magnitude hotter than the underlying photosphere, but how the corona attains such high temperatures is still not understood. Soft X-ray (SXR) emission provides important diagnostics for thermal processes in the high-temperature corona, and is also an important driver of ionospheric dynamics at Earth. There is a crucial observational gap between ∼0.2 and ∼4 keV, outside the ranges of existing spectrometers. We present observations from a new SXR spectrometer, the Amptek X123-SDD, which measured the spatially integrated solar spectral irradiance from ∼0.5 to ∼5 keV, with ∼0.15 keV FWHM resolution, during sounding rocket flights on 2012 June 23 and 2013 October 21. These measurements show that the highly variable SXR emission is orders of magnitude greater than that during the deep minimum of 2009, even with only weak activity. The observed spectra show significant high-temperature (5–10 MK) emission and are well fit by simple power-law temperature distributions with indices of ∼6, close to the predictions of nanoflare models of coronal heating. Observations during the more active 2013 flight indicate an enrichment of low first-ionization potential elements of only ∼1.6, below the usually observed value of ∼4, suggesting that abundance variations may be related to coronal heating processes. The XUV Photometer System Level 4 data product, a spectral irradiance model derived from integrated broadband measurements, significantly overestimates the spectra from both flights, suggesting a need for revision of its non-flare reference spectra, with important implications for studies of Earth ionospheric dynamics driven by solar SXRs.

Total bremsstrahlung spectra of thick lead compounds produced by {sup 90}Sr beta emitter in photon energy region of 10–100 keV

Energy Technology Data Exchange (ETDEWEB)

Sharma, Suhansar Jit [Department of Physics, B.B.S.B Polytechnic, Fatehgarh Sahib, Punjab (India); Singh, Tajinder, E-mail: tajindersingh2k9@gmail.com [Department of Physics, Mata Gujri College, Fatehgarh Sahib, Punjab (India); Singh, Doordarshi [Department of Mechanical Engineering, B.B.S.B Engineering College, Fatehgarh Sahib, Punjab (India); Singh, Amrit [Department of Physics, Baba Ajay Singh Khalsa College, Gurdas Nangal, Gurdaspur, Punjab (India); Dhaliwal, A.S. [Department of Physics, Sant Longowal Institute of Engineering & Technology, Longowal (Sangrur), Punjab (India)

2017-06-15

Highlights: • Total bremsstrahlung spectra in thick targets of Pb compounds by {sup 90}Sr in energy range 10–100 keV. • Experimental results show better agreement with the model which includes PB in SA up to 30 keV. • At higher photon energy region 30–100 keV the model which describes OB is more accurate. • Experimental results show positive deviations from the entire models at higher energy end spectrum. - Abstract: The total bremsstrahlung spectra in the thick targets of lead acetate trihydrate (Pb(CH{sub 3}COO){sub 2}·3H{sub 2}O), lead nitrate Pb(NO{sub 3}){sub 2} and lead chloride (PbCl{sub 2}) produced by {sup 90}Sr beta particles have been investigated in the photon energy region of 10–100 keV. The experimental bremsstrahlung spectra have been compared with the theoretical models Elwert corrected (non relativistic) Bethe Heitler theory, modified Elwert factor (relativistic) Bethe Heitler theory for ordinary bremsstrahlung and modified Elwert factor (relativistic) Bethe Heitler theory which includes polarization bremsstrahlung in the stripped atom approximation. The experimental results show better agreement with theoretical model that includes polarization bremsstrahlung in stripped approximation in the photon energy region below 30 keV. However, at higher photon energy region 30–100 keV, the theoretical model which describes ordinary bremsstrahlung is more accurate to describe the experimental bremsstrahlung spectra. The experimental results show positive deviations from the entire theoretical models at higher energy end of the spectrum. The results indicate that polarization bremsstrahlung plays important role in the formation of total bremsstrahlung spectra in lead compounds produced by continuous beta particles at low photon energy region of 10–30 keV.

keV right-handed neutrinos from type II seesaw mechanism in a 3-3-1 model

International Nuclear Information System (INIS)

Cogollo, D.; Diniz, H.; Pires, C.A. de S

2009-01-01

We adapt the type II seesaw mechanism to the framework of the 3-3-1 model with right-handed neutrinos. We emphasize that the mechanism is capable of generating small masses for the left-handed and right-handed neutrinos and the structure of the model allows that both masses arise from the same Yukawa coupling. For typical values of the free parameters of the model we may obtain at least one right-handed neutrino with mass in the keV range. Right-handed neutrino with mass in this range is a viable candidate for the warm component of the dark matter existent in the universe.

Study of the X radiation between 10 and 100 keV produced in and above the atmosphere

International Nuclear Information System (INIS)

Rothenflug, Robert

1969-01-01

To measure the X radiation within this energy range we used a detector consisting of a NaI(Tl) scintillator combined with a photomultiplier, of surface area 7 cm 2 and yield close to 1 between 10 and 100 keV. The detection system was carried by stratospheric balloons to altitudes (of the order of 40 km) where the atmosphere was sufficiently transparent to allow observation of radiation from outside the atmosphere. At the same time the atmosphere is the centre of ionising radiations which give rise to parasitic X-rays in air and in the materials surrounding the detector. The first part of this report is devoted to a study of these parasitic radiations for the purpose of calculating the different components. The second part deals with diffuse X radiation of extra-terrestrial origin. Measurements of the radiation in 3 different directions showed that it is isotropic within the limits of experimental accuracy, of the order of 20 per cent. The diffuse X-ray spectrum takes the form dN/dE = (2.1 ± 0.4).10 2 E -2.43±0.05 ph/cm 2 .s.ster.keV for E expressed in keV, between 14 and 90 keV., The last part is devoted to a discussion on the possible origins of the diffuse radiation. (author) [fr

Efficient focusing of 8 keV X-rays with multilayer Fresnel zone plates fabricated by atomic layer deposition and focused ion beam milling

International Nuclear Information System (INIS)

Mayer, Marcel; Keskinbora, Kahraman; Grévent, Corinne; Szeghalmi, Adriana; Knez, Mato; Weigand, Markus; Snigirev, Anatoly; Snigireva, Irina; Schütz, Gisela

2013-01-01

The fabrication and performance of multilayer Al 2 O 3 /Ta 2 O 5 Fresnel zone plates in the hard X-ray range and a discussion of possible future developments considering available materials are reported. Fresnel zone plates (FZPs) recently showed significant improvement by focusing soft X-rays down to ∼10 nm. In contrast to soft X-rays, generally a very high aspect ratio FZP is needed for efficient focusing of hard X-rays. Therefore, FZPs had limited success in the hard X-ray range owing to difficulties of manufacturing high-aspect-ratio zone plates using conventional techniques. Here, employing a method of fabrication based on atomic layer deposition (ALD) and focused ion beam (FIB) milling, FZPs with very high aspect ratios were prepared. Such multilayer FZPs with outermost zone widths of 10 and 35 nm and aspect ratios of up to 243 were tested for their focusing properties at 8 keV and shown to focus hard X-rays efficiently. This success was enabled by the outstanding layer quality thanks to ALD. Via the use of FIB for slicing the multilayer structures, desired aspect ratios could be obtained by precisely controlling the thickness. Experimental diffraction efficiencies of multilayer FZPs fabricated via this combination reached up to 15.58% at 8 keV. In addition, scanning transmission X-ray microscopy experiments at 1.5 keV were carried out using one of the multilayer FZPs and resolved a 60 nm feature size. Finally, the prospective of different material combinations with various outermost zone widths at 8 and 17 keV is discussed in the light of the coupled wave theory and the thin-grating approximation. Al 2 O 3 /Ir is outlined as a promising future material candidate for extremely high resolution with a theoretical efficiency of more than 20% for as small an outermost zone width as 10 nm at 17 keV

Variable Gap Undulator for 1.5-48 Kev Free Electron Laser at Linac Coherent Light Source

International Nuclear Information System (INIS)

2011-01-01

We study the feasibility of generating femtosecond duration Free-Electron Laser with a variable photon energy from 1.5 to 48 keV, using an electron bunch with the same characteristics of the LINAC Coherent Light Source (LCLS) bunch, and a planar undulator with additional focusing. We assume that the electron bunch energy can be changed, and the undulator has a variable gap, allowing a variable undulator parameter. It is assumed to be operated in an ultra-low charge and ultra-short pulse regime. We study the feasibility of a tunable, short pulse, X-ray FEL with photon energy from 1.5 to 48 keV, using an electron beam like the one in the LCLS and a 2:5 cm period, variable gap, planar undulator. The beam energy changes from 4.6 to 13.8 GeV, the electorn charge is kept at 10 pC, and the undulator parameter varies from 1 to 3. The undulator length needed to saturate the 48 keV FEL is about 55 m, with a peak power around 5 GW. At longer wavelength the saturation length is as short as 15 m, and the peak power around 20 GW. The results from the analytical models and the GENESIS simulations show that the system is feasible. The large wavelength range, full tunability and short, few femtosecond pulses, together with the large peak power, would provide a powerful research tool.

Evolution of nanodot morphology on polycarbonate (PC) surfaces by 40 keV Ar"+

International Nuclear Information System (INIS)

Goyal, Meetika; Chawla, Mahak; Gupta, Divya; Shekhawat, Nidhi; Sharma, Annu; Aggarwal, Sanjeev

2016-01-01

In the present paper we have discussed the effect of 40 keV Ar"+ ions irradiation on nanoscale surface morphology of Polycarbonate (PC) substrate. Specimens were sputtered at off normal incidences of 30°, 40° and 50° with the fluence of 1 × 10"1"6 Ar"+cm"−"2. The topographical behaviour of specimens was studied by using Atomic Force Microscopy (AFM) technique. AFM study demonstrates the evolution of nano dot morphology on PC specimens on irradiating with 1 × 10"1"6 Ar"+cm"−"2. Average size of dots varied from 37-95 nm in this specified range of incidence while density of dots varied from 0.17-3.0 × 107 dotscm"−"2. Such variations in morphological features have been supported by estimation of ion range and sputtering yield through SRIM simulations.

X-ray variability of the BL Lacertae object PKS 2155 - 304 in the 0.1-6 keV range

International Nuclear Information System (INIS)

Morini, M.; Chiappetti, L.; Maccagni, D.; Maraschi, L.; Molteni, D.; CNR, Istituto di Fisica Cosmica, Milan, Italy; CNR, Istituto di Fisica Cosmica; Milano Universita, Italy; Palermo Universita, Italy)

1986-01-01

Observations of the bright BL Lac object PKS 2155 - 304 obtained at 1-6 keV using the ME argon counters and channel-multiplier array at the focus of the Exosat LE telescope, in conjunction with the 0.05-2-keV-bandpass 3000-A Lexan filter, during a total of 30 h in October-November 1983 and November 1984 are reported. The data are presented in tables and graphs and characterized. Findings discussed include an overall variation of a factor of 10, one factor-of-four increase over 4 h, and maximum luminosity variation dL/dt = 2 x 10 to the 42nd erg/s sq for H = 100 km/s Mpc (corresponding to a lower limit of mass of 10 to the 8th solar mass and a gravitational radius of 3 x 10 to the 13th cm). The implications of these results for theoretical models of the X-ray emission source are considered. 17 references

The interaction between Xe and F in Si (1 0 0) pre-amorphised with 20 keV Xe and implanted with low energy BF{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Werner, M. [Joule Physics Laboratory, Institute of Materials Research, University of Salford, Salford M54WT (United Kingdom)]. E-mail: m.werner@pgr.salford.ac.uk; Berg, J.A. van den [Joule Physics Laboratory, Institute of Materials Research, University of Salford, Salford M54WT (United Kingdom); Armour, D.G. [Joule Physics Laboratory, Institute of Materials Research, University of Salford, Salford M54WT (United Kingdom); Carter, G. [Joule Physics Laboratory, Institute of Materials Research, University of Salford, Salford M54WT (United Kingdom); Feudel, T. [AMD Saxony LLC and Co. KG, Wilschdorfer Landstrasse, 101 D-01109 Dresden (Italy); Herden, M. [AMD Saxony LLC and Co. KG, Wilschdorfer Landstrasse, 101 D-01109 Dresden (Italy); Bersani, M. [ITC IRST, 38050 Povo, Trento (Italy); Giubertoni, D. [ITC IRST, 38050 Povo, Trento (Italy); Bailey, P. [CCLRC Daresbury Laboratory, Daresbury WA44A (United Kingdom); Noakes, T.C.Q. [CCLRC Daresbury Laboratory, Daresbury WA44A (United Kingdom)

2004-12-15

The pre-amorphisation of Si by Xe{sup +} ions, before source/drain and extension implants, is an attractive alternative to Ge{sup +} or Si{sup +}, as it produces sharper amorphous/crystalline interfaces. Si (1 0 0) samples pre-amorphised with 20 keV Xe{sup +} to a nominal dose of 2E14 cm{sup -2} were implanted with 1 and 3 keV BF{sub 2} {sup +} to doses of 7E14 cm{sup -2}. Samples were annealed at temperatures ranging from 600 to 1130 deg. C and investigated by medium energy ion scattering (MEIS) and secondary ion mass spectrometry (SIMS). Following annealing, it was observed that implanted Xe has interacted with F originating from the BF{sub 2} {sup +} implant. MEIS studies showed that for all annealing conditions, approximately half of the Xe accumulated at depths of 7 nm for the 1 keV and at 13 nm for the 3 keV BF{sub 2} {sup +} implant. This equates to the end of range of B and F within the amorphous Si. SIMS showed that in the pre-amorphised samples, approximately 10% of the F migrates into the bulk and is trapped at the same depth in a {approx}1:1 ratio to Xe. A small fraction of the implanted B is also trapped. The effect is interpreted in terms of the formation of a defect structure within the amorphised Si, leading to F stabilised Xe bubble or XeF compound formation.

Linac4 45 keV Proton Beam Measurements

CERN Document Server

Bellodi, G; Hein, L M; Lallement, J-B; Lombardi, A M; Midttun, O; Scrivens, R; Posocco, P A

2013-01-01

Linac4 is a 160 MeV normal-conducting H- linear accelerator, which will replace the 50 MeV proton Linac2 as injector for the CERN proton complex. Commissioning of the low energy part - comprising the H - source, a 45 keV Low Energy Beam Transport line (LEBT), a 3 MeV Radiofrequency Quadrupole (RFQ) and a Medium Energy Beam Transport (MEBT) - will start in fall 2012 on a dedicated test stand installation. In preparation to this, preliminary measurements were taken using a 45 keV proton source and a temporary LEBT setup, with the aim of characterising the output beam by comparison with the predictions of simulations. At the same time this allowed a first verification of the functionalities of diagnostics instrumentation and acquisition software tools. Measurements of beam profile, emittance and intensity were taken in three different setups: right after the source, after the first and after the second LEBT solenoids respectively. Particle distributions were reconstructed from emittance scan...

Influence of ~7 keV sterile neutrino dark matter on the process of reionization

DEFF Research Database (Denmark)

Rudakovskyi, Anton; Iakubovskyi, Dmytro

2016-01-01

Recent reports of a weak unidentified emission line at ~3.5 keV found in spectra of several matter-dominated objects may give a clue to resolve the long-standing problem of dark matter. One of the best physically motivated particle candidate able to produce such an extra line is sterile neutrino...... neutrino dark matter able to produce the observed line at ~3.5 keV, to the process of reionization. By incorporating dark matter power spectra for ~7 keV sterile neutrinos into extended semi-analytical `bubble' model of reionization we obtain that such sterile neutrino dark matter would produce...

STARCODES, Stopping Power and Ranges for Electrons, Protons, He

International Nuclear Information System (INIS)

2000-01-01

1 - Description of program or function: The 'STAR CODES', ESTAR, PSTAR, and ASTAR, calculate stopping-power and range tables for electrons, protons, and helium ions (alphas), according to methods described in ICRU Reports 37 and 39. 2 - Method of solution: Collision stopping powers are calculated from the theory of Bethe (1930, 1932), with a density-effect correction evaluated according to Sternheimer (1952, 1982). The stopping-power formula contains an important parameter, the mean excitation energy (I-value), which characterizes the stopping properties of a material. The codes provide output for electrons in any stopping material (279 provided) and for protons and helium ions in 74 materials. The calculations include the 1) Collision stopping power, 2) Radiative stopping power (electrons only), 3) Nuclear stopping power (protons and helium ions), 4) Total stopping power, 5) CSDA range, 6) Projected range (protons and helium ions), 7) Density effect parameter (electrons), 8) Radiation yield (electrons), and 9) Detour factor (protons and helium ions). Standard energy grids and files of elements w/ionization-excitation information are included with lookup table capabilities. 3 - Restrictions on the complexity of the problem: The minimum energies used in the calculations are at 1 KeV (protons and helium ions) and 10 KeV (electrons), and the maximum are 1 GeV. The standard energy grids are set at 81 for electrons, equally spaced (logarithmically), 133 for protons, and 122 for helium ions. The lower energy electron calculations (< 10 KeV) have up to 5-10% errors and are considered too fallable

Compton scattering of 145 keV gamma rays by K-shell electrons of silver

Energy Technology Data Exchange (ETDEWEB)

Acharya, V B; Singh, B; Ghumman, B S [Punjabi Univ., Patiala (India). Dept. of Physics

1981-01-01

Differential cross-sections for the incoherent scattering of 145 keV photons from K-shell electrons of silver are measured at scattering angles ranging from 30/sup 0/ to 150/sup 0/ to investigate the effect of electron binding on the scattering process in the low energy region. Measurements are made employing two NaI (Tl) scintillation spectrometers and a slow-fast coincidence circuit of resolving time 30 ns. The experimental results are compared with the available theoretical data. The total K-shell scattering cross-section is also estimated and is about 45% of the free electron cross-section.

Observations of 35- 10 1600-keV protons and low-frequency waves upstream of interplanetary shocks

International Nuclear Information System (INIS)

Sanderson, T.R.; Reinhard, R.; Van Nes, P.; Wenzel, K.P.; Smith, E.J.; Tsurutani, B.T.; California Institute of Technology, Pasadena)

1985-01-01

The present investigation is concerned with a comparison of measurements of energetic protons in the range from 35 to 1600 keV and low-frequency waves (periods of approximately 6 s) on ISEE 3 associated with the passage of the large oblique shock of April 5, 1979, which exhibits an extended foreshock. An attempt is made to identify the energy of the particles which are responsible for the waves. Intensity profiles of both waves and particles as a function of upstream distance are compared, taking into account the relation between the energy of the particles and the period of the waves. The considered approach makes it possible to identify protons with energies of a few hundred keV as being responsible for the waves in the extended foreshock. It is believed that the high energy density of the high-energy solar flare protons preceding the shock could be responsible for seed waves which provide the scattering centers necessary for the acceleration of the lower-energy protons via a first-order Fermi mechanism. 31 references

Compact 80-keV neutral-beam module

International Nuclear Information System (INIS)

Molvik, A.W.; Baird, E.D.; Berkner, K.H.; Cooper, W.S.; Duffy, T.J.; Ehlers, K.W.; Fink, J.; Garner, D.; Wilder, C.

1977-01-01

A compact and maintainable source of 80-keV neutral beams that focus to a high power density is required for the Mirror Fusion Test Facility (MFTF). In the new source being designed and built to meet these requirements, the cross-sectional area is reduced in two ways: by immersing the source in a vacuum where high voltage can be held over smaller distances and by redesigning grid supporting structures. Reliability is increased by reducing the electric fields everywhere else below those present between grids and by design innovations. The latter include techniques to reduce stray magnetic field and disperse gas uniformly, all metal-ceramic construction, and a 60-kV shield enclosing all 80-kV electrodes. Wherever possible, we have attempted to simplify the construction. We expect to solve problems that arise during testing either with add-on fixes or with the techniques already tested successfully on the Lawrence Berkeley Laboratory (LBL) 120-keV source. Easy maintenance is obtained by a compact isolation valve and by modular construction. Curving both the grid wires and their holders provides focusing in two planes

Radiation-induced effects in MgO single crystal by 200 keV and 1 MeV Ni ion implantation

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Ryohei; Nakai, Yoshihiro; Hamaguchi, Dai [Kyoto Inst. of Tech. (Japan); and others

1997-03-01

MgO(100) single crystals were implanted with 1.0 MeV and 200 keV Ni ions between 10{sup 15} and 10{sup 17} ions/cm{sup 2} at room temperature. Before and after thermal annealing the radiation damage and the lattice location of implanted Ni ions were analyzed by using Rutherford backscattering spectrometry with channeling and optical absorption measurements. For 1.0 MeV Ni ions, the disorder of Mg atoms increased slowly with ion dose near surface region, while it increased sharply and saturated with ion dose from 2x10{sup 16} ions/cm{sup 2} near ion range. The radiation damage was recovered and implanted Ni ions diffused to the whole of crystal and occupied substitutional positions after 1400degC annealing. For 200 keV Ni ions, the disorder of Mg atoms increased with dose near ion range and had a maximum at about 5x10{sup 16} ions/cm{sup 2}. This tendency agrees with the behavior of color centers obtained from optical measurements. For thermal annealing the radiation damage did not change during 500degC annealing, but the aggregate centers appeared after 300degC annealing. (author)

Perturbation of angular correlations of 180-86 keV cascade in sup(155)G

International Nuclear Information System (INIS)

Budzynski, M; Lebedev, N.A.; Ljzurej, G.; Nezgoda, Kh.; Kochetov, O.I.; Muminov, A.I.; Khazratov, T.

1980-01-01

Using the differential disturbed angular correlation method attenuation of a correlation of the 180-86 keV cascade directions in 155 Gd has been studied. Coefficients of integral angular γγ-correlations for 155 Gd have been measured by an automatic correlation spectrometer with a Ge(Li) and two NaI(Tl) detectors. The obtained correlation coefficients are listed in a table. A fragment of the 155 Tb decay scheme, delayed-coincidence curves and a γ-spectrum are presented. During the analysis of experimental data on the differential disturbed angular correlation the nondisturbed correlation coefficient A 22 (O)=-0.220(4) for the 180-86 keV cascade has been obtained. Basing on this result the multipole composition of the 180 keV transition has been determined: M1+(3.54)% E2 with the mixing ratio delta=0.188. It has been found that at a low temperature strong attenuation of the 180-86 keV cascade angular correlation has been observed [ru

The 7 keV axion dark matter and the X-ray line signal

International Nuclear Information System (INIS)

Higaki, Tetsutaro; Takahashi, Fuminobu; Tokyo Univ., Kashiwa

2014-03-01

We propose a scenario where the saxion dominates the energy density of the Universe and reheats the standard model sector via the dilatonic coupling, while its axionic partner contributes to dark matter decaying into photons via the same operator in supersymmetry. Interestingly, for the axion mass m a ≅ 7 keV and the decay constant f a ≅10 14-15 GeV, the recently discovered X-ray line at 3.5 keV in the XMM Newton X-ray observatory data can be explained. We discuss various cosmological aspects of the 7 keV axion dark matter such as the production of axion dark matter, the saxion decay process, hot dark matter and isocurvature constraints on the axion dark matter, and the possible baryogenesis scenarios.

Study of TGEs and Gamma-Flashes from thunderstorms in 20-3000 keV energy range with SINP MSU Gamma-Ray spectrometers

International Nuclear Information System (INIS)

Bogomolov, V.V.; Svertilov, S.I.; Maximov, I.A.; Panasyuk, M.I.; Garipov, G.K.

2016-01-01

SINP MSU provided a number of experiments with scintillator gamma-spectrometers for study of spectral, temporal and spatial characteristics of TGEs as well as for search of fast hard x-ray and gamma-ray flashes probably appearing at the moment of lightning. The measurements were done in Moscow region and in Armenia at Aragats Mountain. Each instrument used in this work was able to record data in so called “event mode”: the time of each interaction was recorded with ∼15 mcs accuracy together with detailed spectral data. Such design allowed one to look for fast sequences of gamma-quanta, coming at the moments of discharges during thunderstorms. The pulse-shape analysis made by detector electronics was used to separate real gammaray events and possible imitations of flashes by electrical disturbances when discharges occur. During the time period from spring to autumn of 2015 a number of TGEs were detected. Spectral analysis of received data showed that the energy spectrum of coming radiation in 20-3000 kev range demonstrate a set of gamma-ray lines that can be interpreted as radiation from Rn-222 daughter isotopes. The increase of Rn-222 radiation was detected during rainfalls with thunderstorm as well as during rainy weather without thunderstorms. Variations of Rn-222 radiation dominate in low energies (<2.6MeV) and must be taken into account in the experiments performed to measure low energy gamma-radiation from the electrons accelerated in thunderclouds. In order to determine the direction from which the additional gamma-quanta come the experiment with collimated gamma-spectrometer placed on rotated platform was done. The results of this experiment realized in Moscow region from august, 2015 will be presented as well as the results of comparison of different TGEs measured in Moscow region and in Armenia. (author)

A proton polarimeter for beam energies below 300 keV

International Nuclear Information System (INIS)

Buchmann, L.

1990-10-01

A nuclear polarimeter based on the low energy analyzing power of the 6 Li(p, 3 He)α reaction has been developed and tested for proton energies below E p =300 keV. The polarimeter uses a 6 LiF target evaporated on a water cooled tantalum backing. The target is observed at backwards angles by four silicon surface barrier detectors. The energy dependence of the analyzing power under 130 o for the 6 Li(p, 3 He)α reaction has been determined down to 200 keV. Spin rotation has been observed via a magnetic field incorporated in a Wien filter demonstrating that the polarimeter is operational. (Author) (7 refs., 7 figs.)

On the Spectral Hardening at gsim300 keV in Solar Flares

Science.gov (United States)

Li, G.; Kong, X.; Zank, G.; Chen, Y.

2013-05-01

It has long been noted that the spectra of observed continuum emissions in many solar flares are consistent with double power laws with a hardening at energies gsim300 keV. It is now widely believed that at least in electron-dominated events, the hardening in the photon spectrum reflects an intrinsic hardening in the source electron spectrum. In this paper, we point out that a power-law spectrum of electrons with a hardening at high energies can be explained by the diffusive shock acceleration of electrons at a termination shock with a finite width. Our suggestion is based on an early analytical work by Drury et al., where the steady-state transport equation at a shock with a tanh profile was solved for a p-independent diffusion coefficient. Numerical simulations with a p-dependent diffusion coefficient show hardenings in the accelerated electron spectrum that are comparable with observations. One necessary condition for our proposed scenario to work is that high-energy electrons resonate with the inertial range of the MHD turbulence and low-energy electrons resonate with the dissipation range of the MHD turbulence at the acceleration site, and the spectrum of the dissipation range ~k -2.7. A ~k -2.7 dissipation range spectrum is consistent with recent solar wind observations.

Development of 350 MHz/1000 Watt intermediate power amplifier for 400 keV RFQ accelerator

International Nuclear Information System (INIS)

Pande, M.M.; Patel, N.R.; Shinde, K.R.; Rao, M.K.V.; Handu, V.K.

2005-01-01

Two numbers of high power RF systems, each delivering around 35 to 40 kW of power at 350 MHz are being developed in BARC. These High Power Amplifiers (HPA) cater to the total need of 70 kW of RF power required by the 400 keV (Deuterium) RFQ accelerator. This RFQ will replace the existing 400 keV DC accelerator of 14 MeV Neutron Generator. The RFQ will accelerate a deuterium beam from 50 keV to 400 keV to impinge upon a tritium target inside a sub critical assembly. Each of these 35 / 40 KW HPA requires a drive power of around 1000 / 1500 Watt respectively. Hence a intermediate power amplifier (IPA) bas been designed to deliver the power of 1000 Watt at the rate of 350 MHz. The paper describes the development of this amplifier

Fluence to Effective Dose and Effective Dose Equivalent Conversion Coefficients for Photons from 50 KeV to 10 GeV

International Nuclear Information System (INIS)

Ferrari, A.; Pelliccioni, M.; Pillon, M.

1996-07-01

Effective dose equivalent and effective dose per unit photon fluence have been calculated by the FLUKA code for various geometrical conditions of irradiation of an anthropomorphic phantom placed in a vacuum. Calculations have been performed for monoenergetic photons of energy ranging from 50 keV to 10 GeV. The agreement with the results of other authors, when existing, is generally very satisfactory

17 keV and 30 eV Dirac neutrinos and a techniphoton

International Nuclear Information System (INIS)

Holdom, B.

1985-01-01

We consider four flavors of left-handed Weyl neutrinos forming two Dirac masses, of order 17 keV and 30 eV. The symmetry Lsub(e)+Lsub(tau)-Lsub(μ)-Lsub(lambda) ensures this form of the mass matrix and consistency with experiments. We show how it arises in a technicolor context. The structure of the model can incorporate a techniphoton, an unbroken U(1) gauge symmetry of technifermions, and this makes a 17 keV neutrino cosmologically unstable. (orig.)

The 7 keV axion dark matter and the X-ray line signal

Energy Technology Data Exchange (ETDEWEB)

Higaki, Tetsutaro [KEK, Tsukuba (Japan). Theory Center; Jeong, Kwang Sik [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics; Tokyo Univ., Kashiwa (Japan). Kavli IPMU, TODIAS

2014-03-15

We propose a scenario where the saxion dominates the energy density of the Universe and reheats the standard model sector via the dilatonic coupling, while its axionic partner contributes to dark matter decaying into photons via the same operator in supersymmetry. Interestingly, for the axion mass m{sub a} ≅ 7 keV and the decay constant f{sub a} ≅10{sup 14-15} GeV, the recently discovered X-ray line at 3.5 keV in the XMM Newton X-ray observatory data can be explained. We discuss various cosmological aspects of the 7 keV axion dark matter such as the production of axion dark matter, the saxion decay process, hot dark matter and isocurvature constraints on the axion dark matter, and the possible baryogenesis scenarios.

Evaluation of cross sections for neutron interactions with {sup 238}U in the energy region between 5 keV and 150 keV

Energy Technology Data Exchange (ETDEWEB)

Sirakov, I. [Institute for Nuclear Research and Nuclear Energy, Sofia (Bulgaria); Capote, R.; Trkov, A. [International Atomic Energy Agency, NAPC-Nuclear Data Section, Vienna (Austria); Gritzay, O. [Institute for Nuclear Research, Kyiv (Ukraine); Kim, H.I. [Korea Atomic Energy Research Institute, Nuclear Data Center, Daejeon (Korea, Republic of); Kopecky, S.; Paradela, C.; Schillebeeckx, P. [European Commission, Joint Research Centre, Geel (Belgium); Kos, B. [Jozef Stefan Institute, Ljubljana (Slovenia); Pronyaev, V.G. [Rosatom State Corporation, Atomsrandart, Moscow (Russian Federation)

2017-10-15

Cross sections for neutron interactions with {sup 238}U in the energy region from 5 keV to 150 keV have been evaluated. Average total and capture cross sections have been derived from a least squares analysis using experimental data reported in the literature. The resulting cross sections have been parameterised in terms of average resonance parameters maintaining full consistency with results of optical model calculations by using a dispersive coupled channel optical model potential. The average compound partial cross sections have been expressed in terms of transmission coefficients by applying the Hauser-Feshbach statistical reaction theory including width-fluctuations. A generalized single-level representation compatible with the energy-dependent options of the ENDF-6 format has been applied using standard boundary conditions. The results have been transferred into a full ENDF-6 compatible data file. (orig.)

750 keV beam line construction at the KEK

International Nuclear Information System (INIS)

Ishimaru, H.; Anami, S.; Inagaki, T.; Sakaue, T.; Itoh, K.; Fukumoto, S.

1976-01-01

The construction of 750 keV beam line of the KEK injector of the 12 GeV proton synchrotron was described. The beam line consists of the beam focusing quadrupoles, vacuum system, the electrostatic chopper and the various beam monitors. (author)

Development of a TPC for energy and fluence references in low energies neutronic fields (from 8 keV to 5 MeV)

International Nuclear Information System (INIS)

Maire, Donovan

2015-01-01

In order to judge the measurement reliability, metrology requires to measure quantities with their uncertainties, in relation to a reference through a documented and unbroken chain of calibrations. In neutron radiation field, instrument response has to be known as a function of the neutron energy. Then detector calibrations are required using reference neutron fields. In France, primary reference neutron fields are held by the LNE-IRSN, at the Laboratory for Neutron Metrology and Dosimetry (LMDN). In order to improve reference neutron field characterization, the LNE-IRSN MIMAC μTPC has been developed. This detector is a Time Projection Chamber (TPC), using a gas at low pressure (30 mbar abs. to 1 bar abs.). Nuclear recoils are generated by neutron elastic scattering onto gas atoms. By measuring the nuclear recoil energy and scattering angle, the μTPC detector is able to measure the energy distribution of the neutron fluence between 8 keV and 5 MeV. The main challenge was to perform accurate spectrometry of neutron fields in the keV range, following a primary procedure. First of all, a metrological approach was followed in order to master every physical process taking part in the neutron detection. This approach led to develop the direct and inverse models, representing the detector response function and its inverse function respectively. Using this detailed characterization, the energy distribution of the neutron fluence has been measured for a continuous neutron field of 27 keV. The reconstructed energy is 28,2 ± 4,5 keV, the difference between μTPC integral fluence measurement and other measurement methods is less than 6%. The LNE-IRSN MIMAC μTPC system becomes the only one system able to measure simultaneously energy and fluence at energies lower than 100 keV, following a primary procedure. The project goal is then reached. These measurements at energies lower than 100 keV shows also a non-linearity between the ionization charge and the ion kinetic energy

Angular distribution of ejected electrons from 20 keV He+ impact on He

International Nuclear Information System (INIS)

Tokoro, N.; Takenouchi, S.; Urakawa, J.; Oda, N.

1982-01-01

The angular distributions of ejected electrons in the energy range 5-70 eV have been measured at angles from 30 to 150 0 for 20 keV He + impact on He. The angular dependence of excitation cross sections of autoionisation states 2s 2 1 S and 2p 2 1 D+2s2p 1 P are in good agreement with previous data measured by Bordenave-Montesquieu et al (Phys. Rev.; A25:245 (1982)). The continuous parts of the electron spectra show symmetrical angular distributions around 90 0 in the laboratory frame for low-energy electrons (< approximately equal to 30 eV). These angular distributions are discussed in connection with the molecular autoionisation mechanism. (author)

KevJumba and the Adolescence of YouTube

Science.gov (United States)

Saul, Roger

2010-01-01

This article considers the significance of YouTube as a pedagogical space from which young people can play participatory roles as theorists in their own constructions as popular cultural subjects. Drawing upon the public profile of "KevJumba," a teenager who makes videos of himself on YouTube, the article suggests that representational practices…

K X-Ray production cross sections for 40-180 keV protons

International Nuclear Information System (INIS)

Szegedi, S.; Hassan, M.F.

2002-01-01

In view of the importance of the X-ray production cross-section for the determination of element concentration in a given material, we have measured them experimentally for light elements Sc and Fe using proton beams of energy between 40 and 180 keV. The obtained K X-ray production cross-section is compared with the previous experimental results. The experimental K X-ray production cross-section for proton induced X-ray emission (PIXE) analysis, using low energy (200 keV) accelerator, have been improved

Measurement of the 238U(n ,γ ) cross section up to 80 keV with the Total Absorption Calorimeter at the CERN n_TOF facility

Science.gov (United States)

Wright, T.; Guerrero, C.; Billowes, J.; Cano-Ott, D.; Mendoza, E.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Bécares, V.; Barbagallo, M.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Bosnar, D.; Brugger, M.; Calviño, F.; Calviani, M.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Dietz, M.; Domingo-Pardo, C.; Durán, I.; Dzysiuk, N.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Furman, V.; Gómez-Hornillos, M. B.; Ganesan, S.; García, A. R.; Giubrone, G.; Gonçalves, I. F.; González-Romero, E.; Goverdovski, A.; Griesmayer, E.; Gunsing, F.; Gurusamy, P.; Heftrich, T.; Hernández-Prieto, A.; Jenkins, D. G.; Jericha, E.; Käppeler, F.; Kadi, Y.; Karadimos, D.; Katabuchi, T.; Ketlerov, V.; Khryachkov, V.; Koehler, P.; Kokkoris, M.; Kroll, J.; Krtička, M.; Lampoudis, C.; Langer, C.; Leal-Cidoncha, E.; Lederer, C.; Leeb, H.; Leong, L. S.; Lerendegui-Marco, J.; Losito, R.; Manousos, A.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Paradela, C.; Pavlik, A.; Perkowski, J.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego-Perez, A.; Robles, M.; Roman, F.; Rubbia, C.; Ryan, J. A.; Sabaté-Gilarte, M.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Sedyshev, P.; Tagliente, G.; Tain, J. L.; Tarifeño-Saldivia, A.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vermeulen, M. J.; Versaci, R.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiss, C.; Žugec, P.; n TOF Collaboration

2017-12-01

The radiative capture cross section of a highly pure (99.999%), 6.125(2) grams and 9.56(5)×10-4 atoms/barn areal density 238U sample has been measured with the Total Absorption Calorimeter (TAC) in the 185 m flight path at the CERN neutron time-of-flight facility n_TOF. This measurement is in response to the NEA High Priority Request list, which demands an accuracy in this cross section of less than 3% below 25 keV. These data have undergone careful background subtraction, with special care being given to the background originating from neutrons scattered by the 238U sample. Pileup and dead-time effects have been corrected for. The measured cross section covers an energy range between 0.2 eV and 80 keV, with an accuracy that varies with neutron energy, being better than 4% below 25 keV and reaching at most 6% at higher energies.

X-ray fluorescence in some medium-Z elements excited by 59.5 keV photons

International Nuclear Information System (INIS)

Han, I.; Shahin, M.; Demir, L.; Narmanli, E.

2010-01-01

K X-ray fluorescence parameters cross sections and average shell fluorescence yields) for selected ten elements in the atomic range 42 ≤ Z ≤ 66 have been experimentally determined at photon excitation energy of 59.5 keV. K X-rays emitted from the samples have been counted by a Si (Li) detector. The K spectra for investigated elements have been derived from the measured K shell X-ray spectra by peak fitting process. Experimental results of K X-ray fluorescence parameters have been compared with theory. In general there is an agreement within the standard uncertainties of the experimental and theoretical values

Dipole term and first derivative at K=0 of the generalized oscillator strength of He by keV electron impact

International Nuclear Information System (INIS)

Backx, C.; Tol, R.R.; Wight, G.R.; Wiel, M.J. van der

1975-01-01

An approximate method is described for obtaining the derivative to K 2 of the generalized oscillator strength for keV electron scattering at zero momentum transfer, over a large range of energy losses. The measured data enable the reduction of the systematical uncertainty in the derivation of optical oscillator strengths to below 1%. Results are presented for He over the spectral range of 19 to 65 eV. The data for the derivation are in satisfactory agreement with earlier electron scattering results at lower impact energy and extend over a sufficient range to allow the application of a sum rule for this term of the generalized oscillator strength. (Auth.)

Tables and graphs of photon-interaction cross sections from 0.1 keV to 100 MeV derived from the LLL evaluated-nuclear-data library

International Nuclear Information System (INIS)

Plechaty, E.F.; Cullen, D.E.; Howerton, R.J.

1981-01-01

Energy-dependent evaluated photon interaction cross sections and related parameters are presented for elements H through Cf(Z = 1 to 98). Data are given over the energy range from 0.1 keV to 100 MeV. The related parameters include form factors and average energy deposits per collision (with and without fluorescence). Fluorescence information is given for all atomic shells that can emit a photon with a kinetic energy of 0.1 keV or more. In addition, the following macroscopic properties are given: total mean free path and energy deposit per centimeter. This information is derived from the Livermore Evaluated-Nuclear-Data Library (ENDL) as of October 1978

Tables and graphs of photon-interaction cross sections from 0.1 keV to 100 MeV derived from the LLL Evaluated-Nuclear-Data Library

International Nuclear Information System (INIS)

Plechaty, E.F.; Cullen, D.E.; Howerton, R.J.

1978-01-01

Energy-dependent evaluated photon interaction cross sections and related parameters are presented for elements H through Cf (Z = 1 to 98). Data are given over the energy range from 0.1 keV to 100 MeV. The related parameters include form factors and average energy deposits per collision (with and without fluorescence). Fluorescence information is given for all atomic shells that can emit a photon with a kinetic energy of 0.1 keV or more. In addition, the following macroscopic properties are given: total mean free path and energy deposit per centimeter. This information is derived from the Livermore Evaluated-Nuclear-Data Library (ENDL) as of October 1978

Development of a keV single-ion-implanter for nanofabrication

International Nuclear Information System (INIS)

Yang, C.; Jamieson, D.N.; Hopf, T.; Tamanyan, G.; Spizziri, P.; Pakes, C.; Andresen, S.E.; Hudson, F.; Gauja, E.; Dzurak, A.; Clark, R.G.

2005-01-01

Traditional methods of doping semiconductors have a difficulty meeting the demand for high precision doping due to large statistical fluctuations in the numbers of dopant atoms introduced in the ever shrinking volume in micro- and nano-electronics devices, especially when the fabrication process approaches the nanometre scale. The statistical fluctuations in doping semiconductors for the fabrication of devices with a very small feature size may lead to inconsistent and unreliable performance. This paper describes the adaptation of a commercial ion implanter into a single-ion-implantation system for the accurate delivery of dopants into a nanometre or micrometre area in a silicon substrate. All the implanted ions can be accurately counted with near 100% certainty through online detection using the silicon substrate itself as an ion detector. A variety of ion species including B + , N + , P + at the energy range of 10-15 keV can be delivered in the single ion implantation system. (author). 6 refs., 6 figs

Properties of the transitions populating and depopulating the 279 keV level in /sup 75/As

Energy Technology Data Exchange (ETDEWEB)

Puri, V S; Khurana, C S; Sahota, H S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

1977-09-01

The low-energy gamma-ray spectrum of /sup 75/As from /sup 75/Sc has been investigated using a 6 mm x 6 mm Si(Li) spectrometer. The intensity of the 24.4 keV transition has been found to be 0.07 +- 0.01. No evidence has been found for the presence of a 14.9 keV transition. From directional correlation measurements involving the 24.4 keV transition detected in the Si(Li) detector, the multipolarity of this transition has been found to be delta(E3/M2)sub(24.4) =0.18 +- 0.02. The internal conversion process of the 279 keV transition seems to be normal. No effect of the chemical environment has been observed on the (121 ..gamma..-279..gamma..) directional correlation coefficients.

Absolute Calibration of Image Plate for electrons at energy between 100 keV and 4 MeV

Energy Technology Data Exchange (ETDEWEB)

Chen, H; Back, N L; Eder, D C; Ping, Y; Song, P M; Throop, A

2007-12-10

The authors measured the absolute response of image plate (Fuji BAS SR2040) for electrons at energies between 100 keV to 4 MeV using an electron spectrometer. The electron source was produced from a short pulse laser irradiated on the solid density targets. This paper presents the calibration results of image plate Photon Stimulated Luminescence PSL per electrons at this energy range. The Monte Carlo radiation transport code MCNPX results are also presented for three representative incident angles onto the image plates and corresponding electron energies depositions at these angles. These provide a complete set of tools that allows extraction of the absolute calibration to other spectrometer setting at this electron energy range.

Bragg concentrators for hard (> 10keV) x-ray astronomy: Status report

DEFF Research Database (Denmark)

Pareschi, G.; Frontera, F.; Pasqualini, G.

1997-01-01

The use of focusing telescopes in hard X-ray (E > 10 keV) astronomy will provide better flux sensitivity and imaging performances with respect to the direct-viewing detectors, utilized until now. We present recent results obtained from our group regarding the possible use of Bragg-diffraction tec......The use of focusing telescopes in hard X-ray (E > 10 keV) astronomy will provide better flux sensitivity and imaging performances with respect to the direct-viewing detectors, utilized until now. We present recent results obtained from our group regarding the possible use of Bragg...

The Z accelerator as a source of > 100 kJ of x-rays above 4.8 keV

International Nuclear Information System (INIS)

Deeney, C.; Coverdale, C.A.; Spielman, R.B.

1998-01-01

Recent K-shell scaling experiments on the 20 MA Z accelerator at Sandia National Laboratories have shown that large diameter (40 and 55 mm) arrays can be imploded with 80 to 210 wires of titanium or stainless steel. These implosions have produced up to 150 kJ of > 4.5 keV x-rays and 65 kJ of > 6.0 keV x-rays in 7 to 18 ns FWHM pulses. This is a major advance in plasma radiation source (PRS) capability since there is presently limited test capability above 3 keV. In fact, Z produces more > 4.5 keV x-rays than previous aboveground simulators produced at 1.5 keV. Z also produces some 200 kJ of x-rays between 1 and 3 keV in a continuous spectrum for these loads. The measured spectra and yields are consistent with 1-dimensional MHD calculations performed by NRL. Thermoelastic calorimeters, PVDF gauges, and optical impulse gauges have been successfully fielded with these sources

Electron-Impact Ionization Cross Sections of H, He, N, O, Ar, Xe, Au, Pb Atoms and Their Ions in the Electron Energy Range from the Threshold up to 200 keV

CERN Document Server

Povyshev, V M; Shevelko, V P; Shirkov, G D; Vasina, E G; Vatulin, V V

2001-01-01

Single electron-impact ionization cross sections of H, He, N, O, Ar, Xe, Au, Pb atoms and their positive ions (i.e. all ionization stages) are presented in the electron energy range from the threshold up to 200 keV. The data-set for the cross sections has been created on the basis of available experimental data and calculations performed by the computer code ATOM. Consistent data for the ionization cross sections have been fitted by seven parameters using the LSM method. The accuracy of the calculated data presented is within a factor of 2 that in many cases is sufficient to solve the plasma kinetics problems. Contributions from excitation-autoionization and resonant-ionization processes as well as ionization of atoms and ions are not considered here. The results of the numerical calculations are compared with the well-known Lotz formulae for ionization of neutral atoms and positive ions. The material is illustrated by figures and includes tables of ionization cross sections, binding energies and fitting para...

Sputtering of solid nitrogen by keV helium ions

DEFF Research Database (Denmark)

Ellegaard, O.; Schou, Jørgen; Sørensen, H.

1993-01-01

Solid nitrogen has become a standard material among the frozen molecular gases for electronic sputtering. We have combined measurements of sputtering yields and energy spectra from nitrogen bombarded by 4-10 keV helium ions. The data show that the erosion is electronic rather than knockon...

ON THE SPECTRAL HARDENING AT ∼>300 keV IN SOLAR FLARES

International Nuclear Information System (INIS)

Li, G.; Kong, X.; Zank, G.; Chen, Y.

2013-01-01

It has long been noted that the spectra of observed continuum emissions in many solar flares are consistent with double power laws with a hardening at energies ∼>300 keV. It is now widely believed that at least in electron-dominated events, the hardening in the photon spectrum reflects an intrinsic hardening in the source electron spectrum. In this paper, we point out that a power-law spectrum of electrons with a hardening at high energies can be explained by the diffusive shock acceleration of electrons at a termination shock with a finite width. Our suggestion is based on an early analytical work by Drury et al., where the steady-state transport equation at a shock with a tanh profile was solved for a p-independent diffusion coefficient. Numerical simulations with a p-dependent diffusion coefficient show hardenings in the accelerated electron spectrum that are comparable with observations. One necessary condition for our proposed scenario to work is that high-energy electrons resonate with the inertial range of the MHD turbulence and low-energy electrons resonate with the dissipation range of the MHD turbulence at the acceleration site, and the spectrum of the dissipation range ∼k –2.7 . A ∼k –2.7 dissipation range spectrum is consistent with recent solar wind observations.

Evolution of nanodot morphology on polycarbonate (PC) surfaces by 40 keV Ar{sup +}

Energy Technology Data Exchange (ETDEWEB)

Goyal, Meetika, E-mail: meetika89@gmail.com; Chawla, Mahak; Gupta, Divya; Shekhawat, Nidhi; Sharma, Annu; Aggarwal, Sanjeev [Department of Physics, Kurukshetra University, Kurukshetra - 136119 (India)

2016-05-06

In the present paper we have discussed the effect of 40 keV Ar{sup +} ions irradiation on nanoscale surface morphology of Polycarbonate (PC) substrate. Specimens were sputtered at off normal incidences of 30°, 40° and 50° with the fluence of 1 × 10{sup 16} Ar{sup +}cm{sup −2}. The topographical behaviour of specimens was studied by using Atomic Force Microscopy (AFM) technique. AFM study demonstrates the evolution of nano dot morphology on PC specimens on irradiating with 1 × 10{sup 16} Ar{sup +}cm{sup −2}. Average size of dots varied from 37-95 nm in this specified range of incidence while density of dots varied from 0.17-3.0 × 107 dotscm{sup −2}. Such variations in morphological features have been supported by estimation of ion range and sputtering yield through SRIM simulations.

H+ - He collisions. Study of the elastic and inelastic process for 7.5 keV 0 0

International Nuclear Information System (INIS)

Bergnes, C.

1981-03-01

Doubly differential cross sections resulting from a collision of a protons beam with a helium target are measured. The energy and angular ranges extend from 7.5 to 40 keV and from 0.25 0 to 1.5 0 . We used a numerical treatment for resolving our spectra. We calculated the cross sections for the main collision processes: elastic collision, simple excitation of the target atom and ionisation. The mechanism of the processes have been interpretated using the energy diagram of the molecular system [fr

Mass attenuation and mass energy absorption coefficients for 10 keV to 10 MeV photons; Coefficients d'attenuation massique et d'absorption massique en energie pour les photons de 10 keV a 10 MeV

Energy Technology Data Exchange (ETDEWEB)

Joffre, H; Pages, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1968-07-01

In this report are given the elements allowing the definition of the values of mass attenuation coefficients and mass energy absorption coefficients for some elements and mixtures, necessary for the study of tissue equivalent materials, for photons in the energy range 10 keV to 10 MeV. After a short reminding of the definitions of the two coefficients, follows, in table form, a compilation of these coefficients, as a function of energy, for simple elements, for certain mineral compounds, organic compounds, gases and particularly of soft tissues. (author) [French] Dans ce rapport, sont donnes les elements permettant de determiner les valeurs des coefficients d'attenuation massique et d'absorption massique en energie pour certains elements et melanges necessaires a l'etude des materiaux equivalents aux tissus pour les photons dans le domaine d'energie allant de 10 keV a 10 MeV. Apres un bref rappel des definitions des deux coefficients, suit, sous forme de tableaux, un recueil de ces coefficients, en fonction de l'energie, pour les elements simples, certains composes mineraux, composes organiques, gaz, et, particulierement, pour les tissus mous. (auteur)

Elastic and inelastic processes in H+ + CH2 collisions below the 1.5 keV regime

International Nuclear Information System (INIS)

Suno, Hiroya; Rai, Sachchida N.; Liebermann, Heinz-Peter; Buenker, Robert J.; Kimura, Mineo; Janev, R.K.

2005-01-01

Electron capture and direct elastic scattering in collisions of H + ions with CH 2 molecules between 0.5 and 1.5 keV are theoretically investigated. A molecular representation is adopted within a fully quantum-mechanical approach. Differential cross sections (DCSs) for elastic scattering and electron capture are calculated at 1.5 keV and 0.5 keV for different molecular orientations. Our results indicate that electron capture dynamics and corresponding electron-capture cross sections depend substantially on the molecular orientation, thus revealing a strong steric effect. (author)

Sputtering of solid nitrogen and oxygen by keV hydrogen ions

DEFF Research Database (Denmark)

Ellegaard, O.; Schou, Jørgen; Stenum, B.

1994-01-01

Electronic sputtering of solid nitrogen and oxygen by keV hydrogen ions has been studied at two low-temperature setups. The yield of the sputtered particles has been determined in the energy regime 4-10 keV for H+, H-2+ and H-3+ ions. The yield for oxygen is more than a factor of two larger than...... that for nitrogen. The energy distributions of the sputtered N2 and O2 molecules were measured for hydrogen ions in this energy regime as well. The yields from both solids turn out to depend on the sum of the stopping power of all atoms in the ion. The yield increases as a quadratic function of the stopping power...

Design study of 500 keV H- accelerator for ITER NB system

International Nuclear Information System (INIS)

Kashiwagi, Mieko; Inoue, Takashi

2009-02-01

In the neutral beam (NB) system for heating and current drive of ITER, detailed designs of a five stage Multi Aperture and Multi Grid (MAMuG) accelerator to produce 1 MeV 40 A D- and 870 keV 46 A H - ion beams are ongoing. However, it was expected that shinethrough power from the 870 keV H 0 beam was above tolerable level for the maximum plasma density prior to any H mode. Therefore, it was required to reduce the beam energy to 500 keV with maintaining high beam current. The objective of this study is to identify necessary modifications from the original five stage accelerator to a three stage accelerator to produce 500 keV H - ion beam through the physics design based on a beam optics, a beamlet steering and a stripping loss of negative ions. In the beam optics study utilizing a 2D beam analysis code, necessary modifications in aperture diameter, grid thickness and grid spacing were proposed. In a 3D multi beamlets analysis, aperture offsets in the ESG (Electron Suppression Grid) to compensate beamlet deflections and another aperture offset in the GRG (GRounded Grid) to steer the beamlets to a focal point were designed. In a 3D gas flow analysis, it was confirmed that stripping loss of negative ions was not changed and gas density around the beam source satisfied a design requirement for high voltage holding in a modified accelerator configuration proposed in the beam optics study. Finally, the items for modification were summarized. (author)

Substorm morphology of >100 keV protons

International Nuclear Information System (INIS)

Lundblad, J.Aa.; Soeraas, F.; Aarsnes, K.

1978-06-01

The latitudinal morphology of >100 keV protons at different local times has been studied as a function of substorm activity Acharacteristic pattern has been found: During quiet times there is an isotropic zone centered around 67 0 near midnight, but located on higher latitudes towards dusk and dawn. This zone moves slightly equatorward during the substorm growth phase. During the expansive phase the precipitation spreads poleward apparently to approximately 71 0 near midnight. The protons are precipitated over a large local time interval on the night side, but the most intense fluxes are found in the pre-midnight sector. A further poleward expansion, to more than 75 0 near midnight, seems to take place late in the substorm. Away from midnight the expansion reaches even higher latitudes. During the recovery phase the intensity of the expanded region decreases gradually; the poleward boundary is almost stationary if the interplanetary magnetic field has a northward component and no further substorm activity takes place. Mainly protons with energy below approximately 500 keV are precipitated in the expanded region. On the dayside no increase in the precipitation rates is found during substorm expansion, but late in the substorm an enhanced precipitation is found, covering several degrees of latitude. The low-latitude anisotropic precipitation zone is remarkably stable during substorms. A schematic model is presented and discussed in relation to earlier results. (Auth.)

Contribution of 194.1 keV Resonance to 17O(p, alpha) 14N Reaction Rate using R Matrix Code

International Nuclear Information System (INIS)

Chafa, A.; Messili, F.Z.; Barhoumi, S.

2009-01-01

Knowledge of the 17 O(p, alpha ) 14 N reaction rates is required for evaluating elemental abundances in a number of hydrogen - burning stellar sites. This reaction is specifically very important for nucleosynthesis of the rare oxygen isotope 17 O. Classical novae are thought to be a major source of 17 O in the Galaxy and produce the short-live radioisotope 18 F whose + decay is followed by a gamma ray emission which could be observed with satellites such as the Integral observatory. As the 17 O(p, alpha) 14 N and 17 O(p, alpha ) 18 F reactions govern the destruction of 17 O and the formation of 1 '8F, their rates are decisive in determining the final abundances of these isotopes. Stellar temperatures of primary importance for nucleosynthesis are typically in the ranges T = 0.01-0.1 GK for red giant, AGB, and massive stars, and T 0.01-0.4 GK for classical nova explosions In recent work, we observed, for the first time, a resonance a 183.3 keV corresponding to level in 18 F at Ex 5789.8 ± 0.3 keV. A new astrophysical parameters of this resonance are found. In this work we study this reaction using numerical code based on R matrix method including the new values of level energy and parameters of 183.3 keV resonance in order to show his contribution to 17 O(p, alpha) 14 N reaction rates. We also use old parameters values of this resonance given in Keiser work for comparison. We show that this resonance predominate the reaction rates in all range of stellar temperature for classical nova explosions. This is in good agreement with our work with experimental method. We also study cross section and differential cross section 17 O(p, alpha ) 14 N reaction with R matrix method

The appearance and disappearance of the 17-keV neutrino

International Nuclear Information System (INIS)

Franklin, A.

1995-01-01

It is a fact of life in empirical science that experiments often give discordant results. This is nowhere better illustrated than in the recent history of experiments concerning the existence of a heavy, 17-keV neutrino. The 17-keV neutrino was first ''discovered'' by Simpson in 1985. The initial replications of the experiment all gave negative results, and suggestions were made that attempted to explain Simpson's result using accepted physics, without the need for a heavy neutrino. Subsequent positive results by Simpson and others led to further investigation. Several of these later experiments found evidence supporting that claim, whereas others found no evidence for such a particle. Some theorists attempted to explain away the result, and others tried to explain it and to incorporate it within existing theory without the need for a new particle, or to look for the further implications of such a particle, or to propose a new theory that would incorporate the new particle. The question of the existence of such a heavy neutrino remained for several years. Recently, doubt has been cast on the two most convincing positive experimental results, and errors have been found in those experiments. In addition, recent, extremely sensitive experiments have found no evidence for the 17-keV neutrino. The consensus is that it does not exist. The discord has been resolved by a combination of finding errors in one set of experiments and a preponderance of evidence

SMM detection of diffuse Galactic 511 keV annihilation radiation

Science.gov (United States)

Share, G. H.; Kinzer, R. L.; Kurfess, J. D.; Messina, D. C.; Purcell, W. R.

1988-01-01

Observations of the 511 keV annihilation line from the vicinity of the Galactic center from October to February for 1980/1981, 1981/1982, 1982/1983, 1984/1985, and 1985/1986 are presented. The measurements were made with the gamma-ray spectrometer on the SMM. The design of the instrument and some of its properties used in the analysis are described, and the methods used for accumulating, fitting, and analyzing the data are outlined. It is shown how the Galactic 511 keV line was separated from the intense and variable background observed in orbit. The SMM observations are compared with previous measurements of annihilation radiation from the Galactic center region, and the astrophysical implications are discussed. It is argued that most of the measurements made to date suggest the presence of an extended Galactic source of annihilation radiation.

Effects of electronic excitation in 150 keV Ni ion irradiation of metallic systems

Science.gov (United States)

Zarkadoula, Eva; Samolyuk, German; Weber, William J.

2018-01-01

We use the two-temperature model in molecular dynamic simulations of 150 keV Ni ion cascades in nickel and nickel-based alloys to investigate the effect of the energy exchange between the atomic and the electronic systems during the primary stages of radiation damage. We find that the electron-phonon interactions result in a smaller amount of defects and affect the cluster formation, resulting in smaller clusters. These results indicate that ignoring the local heating due to the electrons results in the overestimation of the amount of damage and the size of the defect clusters. A comparison of the average defect production to the Norgett-Robinson-Torrens (NRT) prediction over a range of energies is provided.

In situ thin film measurement by X-rays induced by 10 KeV-100 KeV ion beams

International Nuclear Information System (INIS)

Torrisi, L.; Calcagno, L.; Trovato, A.; Foti, G.

1982-01-01

The in situ measurement of thin film thickness between 50 and 100 KeV is described. The method used seems to be flexible enough and can be applied to any type of material. The only parameter intervening in the thickness measurement is the specific energy loss of the proton beams. Film of Al, Cu and Ag have been considered. When the primary beam energy increases the perception in depth of the method grows, reaching 10 μm with 1 MeV beam. In this case the autoabsorption takes place

Elastic and inelastic processes in He+-H2 collisions between 2 and 30 keV

International Nuclear Information System (INIS)

Bergnes, C.; Bordenave-Montesquieu, D.; Boutonnet, A.; Nouet, P.; Dagnac, R.

1986-01-01

The elastic and inelastic processes have been studied for scattering of He + ions by H 2 molecules between 2 and 30 keV in the angular range from 10' to 3 0 by an energy loss technique. The analysis of elastic energy loss against E 0 theta 2 shows that the incident ion is scattered by the entire molecule at low energies whereas at high energies it is scattered by only one atom in the target. Comparison of the relative probabilities of the various excitation processes with the isoelectronic system He + -He demonstrates the different behaviours of a molecular target in the excitation mechanism. (author)

L-shell X-ray production of molybdenum and niobium induced by 1500–3500 keV Xe26+ ions

International Nuclear Information System (INIS)

Guo, Yipan; Yang, Zhihu; Song, Zhangyong; Xu, Qiumei; Chen, Jing; Yang, Bian

2013-01-01

L-shell X-ray production cross sections are measured for molybdenum and niobium target induced by Xe 26+ ions. The incident energy range varies from 1500 to 3500 keV. The experimental results are well reproduced by the binding-energy-modified binary encounter approximation model in the united-atom limit. In addition to target L-shell X-ray spectra, we also observe a weak spectrum which corresponds to the forbidden transition 3d → 2s from the projectiles

Electron double differential distribution in ionization of helium by 8 keV electron impact

International Nuclear Information System (INIS)

Chatterjee, S.; Agnihotri, A.; Mahtre, N.; Tribedi, L.C.; Kasthurirangan, S.

2010-01-01

Electrons emitted from He in collision with 8 keV electrons were measured in the energy range from 1 to 400 eV and wide range of observation angles between 30 deg and 150 deg. The measured energy and angular distribution of double differential cross sections (DOCS) of these electrons are compared with the theoretical calculation provided by R.D. Rivarola et al. The single differential cross sections (SDCS) are deduced by integrating the DDCSs over solid angle and emission energy. For the calculation of DDCS for He a first-order Born approximation is employed. Within the framework of this model, both the incident and the scattered electrons are described by plane waves, whereas the initial atomic bound state is described by a Lowdin's wavefunction and the final continuum state for the ionized electron is chosen taken into account the interaction between the emitted electron and the residual target at large asymptotic separations. The experimental data is in reasonably good agreement with the theoretical predictions. (author)

Extension of self-seeding scheme with single crystal monochromator to lower energy <5 keV as a way to generate multi-TW scale pulses at the European XFEL

Energy Technology Data Exchange (ETDEWEB)

Geloni, Gianluca [European XFEL GmbH, Hamburg (Germany); Kocharyan, Vitali; Saldin, Evgeni [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2012-07-15

We propose a use of the self-seeding scheme with single crystal monochromator to produce high power, fully-coherent pulses for applications at a dedicated bio-imaging beamline at the European X-ray FEL in the photon energy range between 3.5 keV and 5 keV. We exploit the C(111) Bragg reflection ({pi}-polarization) in diamond crystals with a thickness of 0.1 mm, and we show that, by tapering the 40 cells of the SASE3 type undulator the FEL power can reach up to 2 TW in the entire photon energy range. The present design assumes the use of a nominal electron bunch with charge 0.1 nC at nominal electron beam energy 17.5 GeV. The main application of the scheme proposed in this work is for single shot imaging of individual protein molecules. (orig.)

Extension of self-seeding scheme with single crystal monochromator to lower energy <5 keV as a way to generate multi-TW scale pulses at the European XFEL

International Nuclear Information System (INIS)

Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni

2012-07-01

We propose a use of the self-seeding scheme with single crystal monochromator to produce high power, fully-coherent pulses for applications at a dedicated bio-imaging beamline at the European X-ray FEL in the photon energy range between 3.5 keV and 5 keV. We exploit the C(111) Bragg reflection (π-polarization) in diamond crystals with a thickness of 0.1 mm, and we show that, by tapering the 40 cells of the SASE3 type undulator the FEL power can reach up to 2 TW in the entire photon energy range. The present design assumes the use of a nominal electron bunch with charge 0.1 nC at nominal electron beam energy 17.5 GeV. The main application of the scheme proposed in this work is for single shot imaging of individual protein molecules. (orig.)

Neutron transmission and capture measurements and analysis of 60Ni from 1 to 450 keV

International Nuclear Information System (INIS)

Perey, C.M.; Harvey, J.A.; Macklin, R.L.; Winters, R.R.; Perey, F.G.

1982-11-01

High-resolution transmission and capture measurements of 60 Ni-enriched targets have been made at the Oak Ridge Electron Linear Accelerator (ORELA) from a few eV to 1800 keV in transmission and from 2.5 keV to 5 MeV in capture . The transmission data from 1 to 450 keV were analyzed with a multi-level R-matrix code which uses the Bayes' theorem for the fitting process. This code provides the energies and neutron widths of the resonances inside the 1- to 450-keV region as well as a possible parameterization for outside resonances to describe the smooth cross section in this region. The capture data were analyzed with a least-squares fitting code using the Breit-Wigner formula. From 2.5 to 450 keV, 166 resonances were seen in both sets of data. Correspondence between the energy scales shows a discontinuity around 300 keV which makes the matching of resonances at higher energies difficult. Eighty-nine resonances were seen in the capture data only. Average parameters for the 30 observed s-wave resonances were deduced. The average level spacing D 0 was found to be equal to 15.2 +- 1.5 keV, the strength function, S 0 , equal to (2.2 +- 0.6) x 10 -4 and the average radiation width, GAMMA/sub γ/, equal to 1.30 +- 0.07 eV. The staircase plot of the reduced level widths and the plot of the Lorentz-weighted strength function averaged over various energy intervals show possible evidence for doorway states. The level densities calculated with the Fermi-gas model for l = 0 and for l > 0 resonances were compared with the cumulative number of observed resonances, but the analysis is not conclusive. The average capture cross section as a function of the neutron incident energy is compared to the tail of the giant electric dipole resonance prediction

Static and time-resolved 10-1000 keV x-ray imaging detector options for NIF

International Nuclear Information System (INIS)

Landen, O.L.; Bell, P.M.; McDonald, J.W.; Park, H.-S.; Weber, F.; Moody, J.D.; Lowry, M.E.; Stewart, R.E.

2004-01-01

High energy (>10 keV) x-ray self-emission imaging and radiography will be essential components of many NIF high energy density physics experiments. In preparation for such experiments, we have evaluated the pros and cons of various static [x-ray film, bare charge-coupled device (CCD), and scintillator + CCD] and time-resolved (streaked and gated) 10-1000 keV detectors

A position sensitive detector using a NaI(Tl)/photomultiplier tube combination for the energy range 200 keV to 10 MeV

International Nuclear Information System (INIS)

Court, A.J.; Dean, A.J.; Yearworth, M.; Younis, F.; Chiappetti, L.; Perotti, F.; Villa, G.; Ubertini, P.; La Padula, C.

1988-01-01

The performance of the position sensitive detector for the ZEBRA low energy gamma-ray imaging telescope is described. The detector consists of 9 position sensitive NaI(Tl) elements each 5.8x5.0x56.0 cm viewed at either end of the long axis by 2 in. photomultiplier tubes. The total active area is 2470 cm 2 with an average positional resolution of 2.1 cm and energy resolution of 15% FWHM at 661.6 keV. The method of flight calibration is described together with the provision within the on-board electronics to correct for sources of error in the calculation of event energy loss and position. The results presented are obtained from the calibration phase of the ZEBRA telescope project. (orig.)

Reflectance spectroscopy of PMMA implanted with 50 keV silicon ions

Energy Technology Data Exchange (ETDEWEB)

Florian, Bojana [Bulgarian Institute of Metrology, 2 Prof. P. Mutafchiev Str., 1797 Sofia (Bulgaria); Stefanov, Ivan [Department of Quantum Electronics, Faculty of Physics, Sofia University, 5 James Bourchier Blvd., 1164 Sofia (Bulgaria); Hadjichristov, Georgi [Institute of Solid State Physics, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria)

2009-07-01

Recently, the modification of the specular reflectivity of PMMA implanted with low-energy (50 keV) silicon ions was studied and nano-clusters formed in PMMA by Si{sup +} implantation were evidenced by Raman spectroscopy and electrical measurements. Further, the optical loss due to off-specular (diffuse) reflectivity of this ion-implanted polymer is also of practical interest for applications such as micro-optical lenses, diffraction gratings, Fresnel lenses, waveguides, etc. We examined both specular and diffuse reflectivity of Si{sup +} implanted PMMA in the UV-Vis-NIR. The effect from Si{sup +} implantation in the dose range 10{sup 14}-10{sup 17} ions/cm{sup 2} is linked to the structure formed in PMMA where the buried ion-implanted layer has a thickness up to 100 nm. As compared to the pristine PMMA, an enhancement of the reflectivity of Si{sup +} implanted PMMA is observed, that is attributed to the modification of the subsurface region of PMMA upon the ion implantation.

TEM study of the ion beam induced damage during 14 kev P+ implantation in silicon

International Nuclear Information System (INIS)

Rubanov, S.; Tamanyan, G.; Hudson, F.; Jamieson, D.N.; McCallum, J.C.; Prawer, S.

2005-01-01

The proposed silicon-based quantum computer architecture comprises an array of phosphorus donor atoms (qubits) positioned with nanometre accuracy beneath the surface of a semiconductor host, using a single ion implantation technique. The average depth of the implanted ions (the projected range R p ), lateral range R p 1, and the distribution of ions about that depth can be approximated as two-dimensional Gaussian with standard deviation ΔR p and ΔR p 1 (lateral straggle). Using transmission electron microscopy (TEM) we studied ion beam induced damage after 14 keV P + implantation in Si. The TEM images allowed us to compare the depth of the amorphous cluster formation to R p , R p 1, ΔR p 1 calculated from SRIM and hence determine evidence for the limitation on the accuracy of the position of the implanted ions imposed by straggling. (author). 4 refs., 3 figs

Accretion Properties of a Sample of Hard X-Ray (<60 keV) Selected Seyfert 1 Galaxies

Science.gov (United States)

Wang, J.; Mao, Y. F.; Wei, J. Y.

2009-02-01

We examine the accretion properties in a sample of 42 hard (3-60 keV) X-ray selected nearby broad-line active galactic nuclei (AGNs). The energy range in the sample is harder than that usually used in similar previous studies. These AGNs are mainly complied from the RXTE All Sky Survey, and complemented by the released INTEGRAL AGN catalog. The black hole masses, bolometric luminosities of AGN, and Eddington ratios are derived from their optical spectra in terms of the broad Hβ emission line. The tight correlation between the hard X-ray (3-20 keV) and bolometric/line luminosity is well identified in our sample. Also identified is a strong inverse Baldwin relationship of the Hβ emission line. In addition, all of these hard X-ray AGNs are biased toward luminous objects with a high Eddington ratio (mostly between 0.01 and 0.1) and a low column density (Simbol-X, and NeXT. Finally, the correlation between RFe (= optical Fe II/Hβ) and disk temperature as assessed by T vprop (L/L Edd)M -1 BH leads us to suggest that the strength of the Fe II emission is mainly determined by the shape of the ionizing spectrum.

Influence of ∼7 keV sterile neutrino dark matter on the process of reionization

International Nuclear Information System (INIS)

Rudakovskyi, Anton; Iakubovskyi, Dmytro

2016-01-01

Recent reports of a weak unidentified emission line at ∼3.5 keV found in spectra of several matter-dominated objects may give a clue to resolve the long-standing problem of dark matter. One of the best physically motivated particle candidate able to produce such an extra line is sterile neutrino with the mass of ∼7 keV . Previous works show that sterile neutrino dark matter with parameters consistent with the new line measurement modestly affects structure formation compared to conventional cold dark matter scenario. In this work, we concentrate for the first time on contribution of the sterile neutrino dark matter able to produce the observed line at ∼3.5 keV, to the process of reionization. By incorporating dark matter power spectra for ∼7 keV sterile neutrinos into extended semi-analytical 'bubble' model of reionization we obtain that such sterile neutrino dark matter would produce significantly sharper reionization compared to widely used cold dark matter models, impossible to 'imitate' within the cold dark matter scenario under any reasonable choice of our model parameters, and would have a clear tendency of lowering both the redshift of reionization and the electron scattering optical depth (although the difference is still below the existing model uncertainties). Further dedicated studies of reionization (such as 21 cm measurements or studies of kinetic Sunyaev-Zeldovich effect) will thus be essential for reconstruction of particle candidate responsible the ∼3.5 keV line.

Angular distribution of ejected electrons from 20 keV He/sup +/ impact on He

Energy Technology Data Exchange (ETDEWEB)

Tokoro, N.; Takenouchi, S.; Urakawa, J.; Oda, N. (Tokyo Inst. of Tech. (Japan). Research Lab. of Nuclear Reactor)

1982-10-28

The angular distributions of ejected electrons in the energy range 5-70 eV have been measured at angles from 30 to 150/sup 0/ for 20 keV He/sup +/ impact on He. The angular dependence of excitation cross sections of autoionisation states 2s/sup 2/ /sup 1/S and 2p/sup 2/ /sup 1/D+2s2p /sup 1/P are in good agreement with previous data measured by Bordenave-Montesquieu et al (Phys. Rev.; A25:245 (1982)). The continuous parts of the electron spectra show symmetrical angular distributions around 90/sup 0/ in the laboratory frame for low-energy electrons (

The 10B(p,α)7Be S(E)-factor from 5 keV to 1.5 MeV using the Trojan Horse Method

Science.gov (United States)

Puglia, Sebastiana Maria Regina; Spitaleri, Claudio; La Cognata, Marco; Lamia, Livio; Broggini, Carlo; Caciolli, Antonio; Carlin, Nelson; Cherubini, Silvio; Cvetinovic, Alexandra; D'Agata, Giuseppe; Dell'aquila, Daniele; Depalo, Rosanna; Gulino, Marisa; Guardo, Giovanni Luca; Indelicato, Iolanda; Lombardo, Ivano; Menegazzo, Roberto; Munhoz, Marcelo Gimenez; Pizzone, Rosario Gianluca; Rapisarda, Giuseppe Gabriele; Rigato, Valentino; Romano, Stefano; Sergi, Maria Letizia; Souza, Francisco; Sparta, Roberta; Tudisco, Salvo; Tumino, Aurora

2018-01-01

The 10B(p,α)7Be reaction is the main responsible for the 10B destruction in stellar interior [1]. In such environments this p-capture process occurs at a Gamow energy of 10 keV and takes places mainly through a resonant state (Ex = 8.701 MeV) of the compound 11C nucleus. Thus a resonance right in the region of the Gamow peak is expected to significantly influence the behavior of the astrophysical S(E)-factor. The 10B(p,α)7Be reaction was studied via the Trojan Horse Method (THM) applied to the 2H(10B,α7Be)n in order to extract the astrophysical S(E)-factor in a wide energy range from 5 keV to 1.5 MeV.

Measurement of 24.3 keV activation cross sections with the iron filter technique

International Nuclear Information System (INIS)

Rimawi, K.; Chrien, R.E.

1975-01-01

By using high-resolution detection techniques, intensities of specific activation lines from 197 Au(n,gamma), 238 U(n,gamma), 127 I(n,gamma), and 115 In(n,gamma) [54 min + 2.2 sec] were recorded, by using the BNL HFBR iron-filtered neutron beam. From a com- parison with the reaction 10 B(n,αgamma), cross sections at 24.3 keV were determined. (24.3 keV neutron activation cross sections, relative 10 B standard). (4 figures) (U.S.)

Irradiation damage in aluminium single crystals produced by 50-keV aluminium and copper ions

DEFF Research Database (Denmark)

Henriksen, L.; Johansen, A.; Koch, J.

1968-01-01

Aluminium single crystals, thin enough to be examined by electron microscopy, have been irradiated with 50-keV aluminium and copper ions. The irradiation fluxes were in the range 1011–1014 cm−2 s−1 and the doses were from 6 × 1012 to 6 × 1014 cm−2. Irradiation along either a or a direction produces...... rows of dislocation loops all lying parallel to one particular direction. If the aluminium target is quenched from 600 °C and annealed at room temperature prior to irradiation with aluminium ions, the rows of loops are suppressed. The amount of damage observed is considerably less than would...

Cryogenic radiometry in the hard X-ray range

International Nuclear Information System (INIS)

Gerlach, M.; Krumrey, M.; Cibik, L.; Muller, P.; Rabus, H.; Ulm, G.

2008-01-01

For many applications in radiometry, spectroscopy or astrophysics, absolute measurement of radiant power with low uncertainty is essential. Cryogenic electrical substitution radiometers (ESRs) are regarded as the highest-accuracy primary standard detector in radiometry, from the infrared to the ultraviolet region; in combination with tuneable monochromatized synchrotron radiation from electron storage rings, their range of operation has been extended to the soft x-ray region. ESRs are absolute thermal detectors, based on the equivalence of electrical power and radiant power that can be traced back to electrical SI units and be measured with low uncertainties. Their core piece is a cavity absorber, which is typically made of copper to achieve a short response time suitable for use with synchrotron radiation. At higher photon energies, the use of copper prevents the operation of ESRs due to increasing transmittance. A new absorber design for hard x-rays has been developed at the laboratory of the Physikalisch-Technische Bundesanstalt (PTB) at the electron storage ring BESSY II. The Monte Carlo simulation code Geant4 was applied to optimize its absorptance for photon energies of up to 60 keV, resulting in a cavity absorber with a gold base and a cylindrical shell made of copper, in combination with a thermal sensitivity of around 150 mK μW -1 and a time constant of less than 3 min, which is short compared with the lifetime of many hours for the storage ring current. The measurement of the radiant power of monochromatized synchrotron radiation was achieved with relative standard uncertainties of less than 0.2%, covering the entire photon energy range of three beamlines from 50 eV to 60 keV. Monochromatized synchrotron radiation of high spectral purity was used to calibrate silicon photodiodes against the ESR for photon energies up to 60 keV with relative standard uncertainties below 0.3%. (authors)

Cryogenic radiometry in the hard X-ray range

Energy Technology Data Exchange (ETDEWEB)

Gerlach, M.; Krumrey, M.; Cibik, L.; Muller, P.; Rabus, H.; Ulm, G. [Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Berlin (Germany)

2008-10-15

For many applications in radiometry, spectroscopy or astrophysics, absolute measurement of radiant power with low uncertainty is essential. Cryogenic electrical substitution radiometers (ESRs) are regarded as the highest-accuracy primary standard detector in radiometry, from the infrared to the ultraviolet region; in combination with tuneable monochromatized synchrotron radiation from electron storage rings, their range of operation has been extended to the soft x-ray region. ESRs are absolute thermal detectors, based on the equivalence of electrical power and radiant power that can be traced back to electrical SI units and be measured with low uncertainties. Their core piece is a cavity absorber, which is typically made of copper to achieve a short response time suitable for use with synchrotron radiation. At higher photon energies, the use of copper prevents the operation of ESRs due to increasing transmittance. A new absorber design for hard x-rays has been developed at the laboratory of the Physikalisch-Technische Bundesanstalt (PTB) at the electron storage ring BESSY II. The Monte Carlo simulation code Geant4 was applied to optimize its absorptance for photon energies of up to 60 keV, resulting in a cavity absorber with a gold base and a cylindrical shell made of copper, in combination with a thermal sensitivity of around 150 mK {mu}W{sup -1} and a time constant of less than 3 min, which is short compared with the lifetime of many hours for the storage ring current. The measurement of the radiant power of monochromatized synchrotron radiation was achieved with relative standard uncertainties of less than 0.2%, covering the entire photon energy range of three beamlines from 50 eV to 60 keV. Monochromatized synchrotron radiation of high spectral purity was used to calibrate silicon photodiodes against the ESR for photon energies up to 60 keV with relative standard uncertainties below 0.3%. (authors)

Cryogenic radiometry in the hard x-ray range

Science.gov (United States)

Gerlach, M.; Krumrey, M.; Cibik, L.; Müller, P.; Rabus, H.; Ulm, G.

2008-10-01

For many applications in radiometry, spectroscopy or astrophysics, absolute measurement of radiant power with low uncertainty is essential. Cryogenic electrical substitution radiometers (ESRs) are regarded as the highest-accuracy primary standard detector in radiometry, from the infrared to the ultraviolet region; in combination with tuneable monochromatized synchrotron radiation from electron storage rings, their range of operation has been extended to the soft x-ray region. ESRs are absolute thermal detectors, based on the equivalence of electrical power and radiant power that can be traced back to electrical SI units and be measured with low uncertainties. Their core piece is a cavity absorber, which is typically made of copper to achieve a short response time suitable for use with synchrotron radiation. At higher photon energies, the use of copper prevents the operation of ESRs due to increasing transmittance. A new absorber design for hard x-rays has been developed at the laboratory of the Physikalisch-Technische Bundesanstalt (PTB) at the electron storage ring BESSY II. The Monte Carlo simulation code Geant4 was applied to optimize its absorptance for photon energies of up to 60 keV, resulting in a cavity absorber with a gold base and a cylindrical shell made of copper, in combination with a thermal sensitivity of around 150 mK µW-1 and a time constant of less than 3 min, which is short compared with the lifetime of many hours for the storage ring current. The measurement of the radiant power of monochromatized synchrotron radiation was achieved with relative standard uncertainties of less than 0.2%, covering the entire photon energy range of three beamlines from 50 eV to 60 keV. Monochromatized synchrotron radiation of high spectral purity was used to calibrate silicon photodiodes against the ESR for photon energies up to 60 keV with relative standard uncertainties below 0.3%.

The Half Life of the 53 keV Level in {sup 197}Pt

Energy Technology Data Exchange (ETDEWEB)

Malmskog, S G

1967-02-15

The half life of the recently proposed 53 keV level in {sup 197}Pt has been measured to 18.5 {+-} 1.5 nsec using the delayed coincidence technique. This level, which is identified with the f{sub 5/2} single particle state, decays directly to the p{sub 1/2} ground state in {sup 197}Pt. The reduced E2 transition probability for this 53 keV transition has been deduced and compared with the results obtained for the corresponding transitions in other Pt, Hg, and Pb isotopes and with the theoretical predictions by Sorensen and by Wahlborn and Martinson.

A very sensitive nonintercepting beam average velocity monitoring system for the TRIUMF 300-keV injection line

International Nuclear Information System (INIS)

Yin, Y.; Laxdal, R.E.; Zelenski, A.; Ostroumov, P.

1997-01-01

A nonintercepting beam velocity monitoring system has been installed in the 300-keV injection line of the TRIUMF cyclotron to reproduce the injection energy for beam from different ion sources and to monitor any beam energy fluctuations. By using a programmable beam signal leveling method the system can work with a beam current dynamic range of 50 dB. Using synchronous detection, the system can detect 0.5 eV peak-to-peak energy modulation of the beam, sensitivity is 1.7x10 -6 . The paper will describe the principle and beam measurement results. copyright 1997 American Institute of Physics

The bremsstrahlung induced by 0.3-2 keV electron scattering by Ar atoms

International Nuclear Information System (INIS)

Gnatchenko, E.V.; Tkachenko, A.A.; Verkhovtseva, E.T.

2002-01-01

The differential spectra of a bremsstrahlung resulting from a 0.3-2 keV electron scattering by Ar atoms are studied. Photon energies within the ultrasoft X-ray band from 124 to 190.8 eV, which is characterized by the low dynamic polarizability of the Ar atom, are considered. For the entire spectrum of photon energies (124-190.8 eV), the intensity of the bremsstrahlung differential spectra first grows with an increase in the electron energy from 0.3 to 0.7 keV and then decreases as the electron energy increases from 0.7 to 2 keV. The increase in intensity is directly proportional, and the decrease is inversely proportional to the square root of the energy of the scattered electrons. Within the context of a 'low-energy' approximation, the increase in the number of photons with the electron energy is due to the contribution of the atomic excitation and ionization channels being available during the bremsstrahlung process

Measurement X radiation > 30 KeV in the Brazilian magnetic anomaly with omnidirectional detectors

International Nuclear Information System (INIS)

Pinto Junior, O.; Gonzalez-Alarcon, W.D.; Gonzalez, A.L.C. de; Martin, I.M.; Dutra, S.L.G.; Pinto, I.R.C.A.; Pereira, A.E.C.; Senador, R.

1982-07-01

Atmospheric X-Rays measurements, with energies > 30 KeV, were performed at Sao Jose dos Campos-Brazil (23 0 S, 46 0 W Geographic) on April 14 and December 19, 1981, using omnidirectional NaI (Tl) scintillation counters on board stratospheric balloons. The main purpose of these measurements is to study the dynamics of precipitating electrons at the Brazilian Magnetic Anomaly. Studies on similar measurements during the previous decade seemed to show the existence of approximately 100 KeV precipitating electrons, possibly related to a coulomb scattering with the atmosophere. The studies on the recent measurements try not only to confirm such indications, but also to show further features of the dynamics of precipitating electrons, mainly during magnetically active time intervals. During such intervals, more energetic electrons (up to approximately 1000 KeV) also seem to precipitate, probably due to resonant wave-particle interactions at the low latitude inner magnetosphere. The collected data during the recent measurements seem to indicate the existence of such interactions. (Author) [pt

Erosion of volatile elemental condensed gases by keV electron and light-ion bombardment

International Nuclear Information System (INIS)

Schou, J.

1991-11-01

Erosion of the most volatile elemental gases by keV electron and light-ion bombardment has been studied at the experimental setup at Risoe. The present work includes frozen neon, argon, krypton, nitrogen, oxygen and three hydrogen isotopes, deuterium, hydrogen deuteride and hydrogen. The yield of these condensed gases has been measured as a function of film thickness and primary energy for almost all combinations of primary particles (1-3 keV electrons, 5-10 keV hydrogen- and helium ions) and ices. These and other existing results show that there are substantial common features for the sputtering of frozen elemental gases. Within the two groups, the solid rare gases and the solid molecular gases, the similarity is striking. The hydrogenic solids deviate in some respects from the other elements. The processes that liberate kinetic energy for the particle ejection in sputtering are characteristic of the specific gas. (au) 3 tabs., 12 ills., 159 refs

High-energy behavior of the double photoionization of helium from 2 to 12 keV

International Nuclear Information System (INIS)

Levin, J.C.; Sellin, I.A.; Johnson, B.M.; Lindle, D.W.; Miller, R.D.; Berrah, N.; Azuma, Y.; Berry, H.G.; Lee, D.

1993-01-01

We report the ratio of double-to-single photoionization of He at several photon energies from 2 to 12 keV. By time-of-flight methods, we find a ratio consistent with an asymptote at 1.5%±0.2%, essentially reached by hν∼4 keV. Fair agreement is obtained with older shake calculations of Byron and Joachain [Phys. Rev. 164, 1 (1967)], of Aberg [Phys. Rev. A 2, 1726 (1970)], and with recent many-body perturbation theory (MBPT) of Ishihara, Hino, and McGuire [Phys. Rev. A 44, 6980 (1991)]. The result lies below earlier MPBT calculations by Amusia et al. [J. Phys. B 8, 1248 (1975)] (2.3%), and well above semiempirical predictions of Samson [Phys. Rev. Lett. 65, 2861 (1990)], who expects no asymptote and predicts σ(He 2+ )/σ(He + )=0.3% at 12 keV

New generation of efficient high resolution detector for 30-100 keV photons

DEFF Research Database (Denmark)

Olsen, Ulrik Lund

between pores. The potential of the structured scintillator is explored through Monte Carlo simulations. A spatial resolution of 1 µm is obtainable and for scintillators with a resolution between 1 µm and 8 µm the efficiency could be more than 15 times higher than a regular scintillator with corresponding...... detector. This establishes an inverse correlation between the spatial resolution and the detection efficiency which limits the performance of existing x-ray detectors. The purpose of this Ph.D. project is to explore alternative paths of research, to develop x-ray detectors for the 30-100 keV energy range...... with single micrometre resolution without compromising efficiency. A number of detector types have been evaluated for this purpose. Structured scintillators are found to exhibit a high potential in terms of performance and also in terms of realizing an actual detector. The structured scintillator consists...

150 keV intense electron beam accelerator system with high repeated pulse

International Nuclear Information System (INIS)

Qi, Zhang; Tixing, Li; Hongfang, Tang; Nenggiao, Xia; Zhigin, Wang; Baohong, Zheng

1993-01-01

A 150 keV electron beam accelerator system has been developed for wide application of high power particle beams. The new wire-ion-plasma electron gun has been adopted. The parameters are as follows: Output energy - 130-150 keV; Electron beam density - 250 mA/cm 2 ; Pulse duration - 1 μs; Pulse rate 100 pps; Section of electron beam - 5 x 50 cm 2 . This equipment can be used to study repeated pulse CO 2 laser, to be a preionizer of high power discharge excimer laser and to perform radiation curing process, and so on. The first part contains principle and design consideration. Next is a description of experimental arrangement. The remainder is devoted to describing experimental results and its application

Study of the reactions 9Be(p, α)6Li, 9Be(p,d)8Be from 300 keV to 900 keV

International Nuclear Information System (INIS)

Bertrand, F.; Grenier, G.; Pornet, J.

1968-10-01

The experimental results concerning the two reactions 9 Be(p,α) 6 Li and 9 Be(p,d) 8 Be from 300 to 900 keV are presented. The angular distribution, excitation and total cross-section curves are expressed in absolute values after a normalization carried out using results given by Weber, Davis and Marion. (authors) [fr

Experimental results on 2-30 keV bremsstrahlung from thick and thin targets

Energy Technology Data Exchange (ETDEWEB)

Shanker, R. [Atomic Physics Laboratory, Physics Department, Banaras Hindu University, Varanasi 221005 (India)]. E-mail: rshanker@bhu.ac.in

2006-10-15

The recent experimental investigations on electron bremsstrahlung produced from impact of 2-30 keV electrons with thick solid and thin gaseous targets are reviewed. The theoretical models describing the energy and angular distributions of bremsstrahlung photons are discussed with their brief outlines and formulations to explain the experimental data. The results on thick target bremsstrahlung (TTB) spectra produced by keV electrons have suggested that there is a need to develop a comprehensive theory for accounting the solid state effects. It is further noted that the prediction of the modified KKD formula gives a reasonable agreement with the TTB data, whereas a semi-empirical formula gives a better fit to the data for thick targets. The available experimental data for dependence of double differential cross-sections of emitted photons on impact energy and their emission angles for gaseous atoms and molecules exhibit a good agreement with the theoretical calculations of Kissel et al., [1983. Shape functions for atomic-field bremsstrahlung from electrons of kinetic energy 1-500 keV on selected neutral atoms 1

Solar wind ∼0.1-1.5 keV electrons at quiet times

Energy Technology Data Exchange (ETDEWEB)

Tao, Jiawei; Wang, Linghua, E-mail: wanglhwang@gmail.com; Zong, Qiugang; He, Jiansen; Tu, Chuanyi [School of Earth and Space Science, Peking University, Beijing 100871 (China); Li, Gang [Department of Physics and CSPAR, University of Alabama in Huntsville, Alabama 35899 (United States); Salem, Chadi S.; Bale, Stuart D. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Wimmer-Schweingruber, Robert F. [Institute for Experimental and Applied Physics, University of Kiel (Germany)

2016-03-25

We present a statistical survey of the energy spectrum of solar wind suprathermal (∼0.1-1.5 keV) electrons measured by the WIND 3-D Plasma & Energetic Particle (3DP) instrument at 1 AU during quiet times at the minimum and maximum of solar cycles 23 and 24. Firstly, we separate strahl (beaming) electrons and halo (isotropic) electrons based on their features in pitch angle distributions. Secondly, we fit the observed energy spectrum of both the strahl and halo electrons at ∼0.1-1.5 keV to a Kappa distribution function with an index κ, effective temperature T{sub eff} and density n{sub 0}. We also integrate the the measurements over ∼0.1-1.5 keV to obtain the average electron energy E{sub avg} of the strahl and halo. We find a strong positive correlation between κ and T{sub eff} for both the strahl and halo, possibly reflecting the nature of the generation of these suprathermal electrons. Among the 245 selected samples, ∼68% have the halo κ smaller than the strahl κ, while ∼50% have the halo E{sub h} larger than the strahl E{sub s}.

The energy spectrum of 662 keV photons in a water equivalent phantom

International Nuclear Information System (INIS)

Akar Tarim, U.; Gurler, O.; Ozmutlu, E.N.; Yalcin, S.; Gundogdu, O.; Sharaf, J.M.; Bradley, D.A.

2012-01-01

Investigation is made on the energy spectrum of photons originating from interactions of 662 keV primary gamma-ray photons emitted by a point source positioned at the centre of a water equivalent solid phantom of dimensions 19 cm×19 cm×24 cm. Peaks resulting from total energy loss (photopeak) and multiple and back scattering have been observed using a 51 mm×51 mm NaI(Tl) detector; good agreement being found between the measured and simulated response functions. The energy spectrum of the gamma photons obtained through the Monte Carlo simulation reveals local maxima at about 100 keV and 210 keV, being also observed in the experimental response function. Such spectra can be used as a method of testing the water equivalence of solid phantom media before their use for dosimetry measurements. - Highlights: ► Peaks resulting from total energy loss (photopeak) and multiple and back scattering were observed. ► Energy distribution of γ-ray photons from a point source at the centre of a water equivalent solid phantom. ► The method can be applied to various detector geometries.

Empirical formulae for mass attenuation and energy absorption coefficients from 1 keV to 20 MeV

International Nuclear Information System (INIS)

Manjunatha, H.C.; Sowmya, N.; Seenappa, L.; Sridhar, K.N.; Hanumantharayappa, C.

2017-01-01

Mass attenuation and energy absorption coefficients represents attenuation and absorption of X-rays and gamma rays in the material medium. A new empirical formula is proposed for mass attenuation and energy absorption coefficients in the region 1 < Z < 92 and from 1 keV to 20 MeV. The mass attenuation and energy absorption coefficients do not varies linearly with energy. We have performed the nonlinear regressions/nonlinear least square fittings and proposed the simple empirical relations between mass attenuation coefficients (μ/ρ) and mass energy absorption coefficients (μ en /ρ) and energy. We have compared the values produced by this formula with that of experiments. A good agreement of present formula with the experiments/previous models suggests that the present formulae could be used to evaluate mass attenuation and energy absorption coefficients in the region 1 < Z < 92. This formula is a model-independent formula and is the first of its kind that produces a mass attenuation and energy absorption coefficient values with the only simple input of energy for wide energy range 1 keV - 20 MeV in the atomic number region 1 < Z < 92. This formula is very much useful in the fields of radiation physics and dosimetry

Radial Profile of the 3.5 kev Line Out to R200 in the Perseus Cluster

Science.gov (United States)

Franse, Jeroen; Bulbul, Esra; Foster, Adam; Boyarsky, Alexey; Markevitch, Maxim; Bautz, Mark; Lakubovskyi, Dmytro; Loewenstein, Michael; McDonald, Michael; Miller, Eric;

Quark nugget dark matter: no contradiction with 511 keV line emission from dwarf galaxies

Energy Technology Data Exchange (ETDEWEB)

Lawson, Kyle; Zhitnitsky, Ariel, E-mail: klawson@phas.ubc.ca, E-mail: arz@phas.ubc.ca [Department of Physics and Astronomy, University of British Columbia, Vancouver, B.C. V6T 1Z1 (Canada)

2017-02-01

The observed galactic 511 keV line has been interpreted in a number of papers as a possible signal of dark matter annihilation within the galactic bulge. If this is the case then it is possible that a similar spectral feature may be observed in association with nearby dwarf galaxies. These objects are believed to be strongly dark matter dominated and present a relatively clean observational target. Recently INTEGRAL observations have provided new constraints on the 511 keV flux from nearby dwarf galaxies [1] motivating further investigation into the mechanism by which this radiation may arise. In the model presented here dark matter in the form of heavy quark nuggets produces the galactic 511 keV emission line through interactions with the visible matter. It is argued that this type of interaction is not strongly constrained by the flux limits reported in [2].

Sputtering characteristics of B4C-overlaid graphite for keV energy deuterium ion irradiation

International Nuclear Information System (INIS)

Gotoh, Y.; Yamaki, T.; Ando, T.; Jimbou, R.; Ogiwara, N.; Saidoh, M.; Teruyama, K.

1992-01-01

Two types of B 4 C-overlaid graphite (CFC), conversion and CVD B 4 C, together with bare CFC (PCC-2S) and/or HP B 4 C, were investigated with respect to erosion yields for 1 keV D + , D 2 /CD 4 TDS after 1 keV D + implantation, and thermal diffusivity/conductivity, in a temperature range from 300 to 1400 K. The erosion yields of both conversion and CVD B 4 C were found to be much lower than that of the bare CFC (PCC-2S), in both chemical sputtering (600-1100 K) and RES (1200-1400 K) temperature regions. The D 2 TDS peak of the conversion B 4 C was found to be located at nearly 200 K lower temperature than that of the bare CFC (PCC-2S), indicating much lower activation energy for detrapping/recombination of trapped D in the conversion B 4 C and in the CFC. The CD 4 TDS peak of the conversion B 4 C was found to be much weaker in intensity than that of the bare CFC (PCC-2S), in agreement with the present erosion yield results. Thermal diffusivities and conductivities of both the conversion B 4 C/PCC-2S and the CVD B 4 C, were measured to be nearly 1/10 of that of the bare CFC (PCC-2S), and to decrease with increasing temperatures. (orig.)

Multiple capture investigated by coincident electron spectroscopy in X7++Ar, at 70 keV

International Nuclear Information System (INIS)

Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A.

1999-01-01

The multiple electron capture in N 7+ + Ar and F 7+ (1s 2 ) + Ar systems is investigated at 70 keV with a new electron-recoil ion charge coincidence experiment. The whole electron energy range has been studied. Up to six electrons are found to be captured into autoionizing states. The recoil ion charge distribution associated with the emission of electrons is similar for both systems and found to be in good agreement with the prediction of Niehaus's model roughly adapted to take into account autoionizing cascades. New findings for the coincident double and triple captures are briefly discussed. A capture of an inner L-shell electron of Ar into the K-shell of the projectile is also observed in N 7+ + Ar collisions. (orig.)

Single-electron capture in keV Ar15+...18++He collisions

NARCIS (Netherlands)

Knoop, S.; Fischer, D.; Xue, Y.; Zapukhlyak, M.; Osborne, C. J.; Ergler, Th; Ferger, T.; Braun, J.; Brenner, G.; Bruhns, H.; Dimopoulou, C.; Epp, S. W.; Martinez, A. J. Gonzalez; Sikler, G.; Orts, R. Soria; Tawara, H.; Kirchner, T.; Lopez-Urrutia, J. R. Crespo; Moshammer, R.; Ullrich, J.; Hoekstra, R.; Gonzales Martinez, A.J.

2008-01-01

Single-electron capture in 14 keV q(-1) Ar15+...18++He collisions is investigated both experimentally and theoretically. Partial cross sections and projectile scattering angle dependencies have been deduced from the target ion recoil momenta measured by the COLTRIMS technique. The comparison with

Design of a continuously operated 1-keV deuterium-ion extractor

International Nuclear Information System (INIS)

Fink, J.H.

1978-01-01

A novel grid structure that is cooled only by radiation and conduction is shown to be capable of continuously extracting 2.5 kA.m -2 of 1-keV positive deuterium ions while dissipating a power loading of 0.4 MW.m -2

Elastic and inelastic processes in He/sup +/-H/sub 2/ collisions between 2 and 30 keV

Energy Technology Data Exchange (ETDEWEB)

Bergnes, C.; Bordenave-Montesquieu, D.; Boutonnet, A.; Nouet, P.; Dagnac, R.

1986-10-14

The elastic and inelastic processes have been studied for scattering of He/sup +/ ions by H/sub 2/ molecules between 2 and 30 keV in the angular range from 10' to 3/sup 0/ by an energy loss technique. The analysis of elastic energy loss against E/sub 0/theta/sup 2/ shows that the incident ion is scattered by the entire molecule at low energies whereas at high energies it is scattered by only one atom in the target. Comparison of the relative probabilities of the various excitation processes with the isoelectronic system He/sup +/-He demonstrates the different behaviours of a molecular target in the excitation mechanism.

Study of the double charge-changing collision cross-sections of H{sup +}, D{sup +}, Li{sup +} ions with organic molecules in the energy range 10-50 keV; Etude des sections efficaces de double echange de charges ({sigma}{sub 1-1}) d'ions H{sup +}, D{sup +}, Li{sup +} traversant differents gaz organiques dans une gamme d'energie comprise entre 10 et 50 keV

Energy Technology Data Exchange (ETDEWEB)

Farrokhi, S [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1966-07-01

The variation of the double charge-changing collision cross-sections of H{sup +}, D{sup +}, Li{sup +} ions with organic molecules (CH{sub 4}, C{sub 2}H{sub 6}, C{sub 3}H{sub 8}, C{sub 4}H{sub 10}) in the energy range 10-50 keV has been studied. Several maximums for {sigma}{sub 1-1} = f(E) have been shown. Their existence should be explained by the different possibilities of dissociating the target-molecules. The position of the maximums, for the H{sup +} {yields} H{sup -} and D{sup +} {yields} D{sup -} reactions is in good agreement with that defined by the Massey adiabatic relation. (author) [French] Nous avons etudie la variation de la section efficace de double echange de charges des ions H{sup +}, D{sup +}, Li{sup +} lors de la collision avec les molecules organiques de CH{sub 4}, C{sub 2}H{sub 6}, C{sub 3}H{sub 8}, C{sub 4}H{sub 10} dans la gamme d'energie comprise entre 10 et 50 keV. Les resultats obtenus ont montre plusieurs maximums de {sigma}{sub 1-1} f(E). L'existence de ces maximums pourrait etre expliquee par les differentes possibilites de dissociation des molecules cibles. La position des points maximaux concernant les reactions H{sup +} {yields} H{sup -} et D{sup +} {yields} D{sup -} est en bon accord avec celle definie par la relation adiabatique de MASSEY. (auteur)

Reducing the effects of metal artefact using high keV monoenergetic reconstruction of dual energy CT (DECT) in hip replacements

Energy Technology Data Exchange (ETDEWEB)

Lewis, Mark [Norfolk and Norwich University Hospital, Norwich (United Kingdom); Norwich Radiology Academy, Norwich (United Kingdom); Reid, Karen [Norfolk and Norwich University Hospital, Norwich (United Kingdom); Toms, Andoni P. [Norfolk and Norwich University Hospital and University of East Anglia, Norwich (United Kingdom)

2013-02-15

The aim of this study was to determine whether high keV monoenergetic reconstruction of dual energy computed tomography (DECT) could be used to overcome the effects of beam hardening artefact that arise from preferential deflection of low energy photons. Two phantoms were used: a Charnley total hip replacement set in gelatine and a Catphan 500. DECT datasets were acquired at 100, 200 and 400 mA (Siemens Definition Flash, 100 and 140 kVp) and reconstructed using a standard combined algorithm (1:1) and then as monoenergetic reconstructions at 10 keV intervals from 40 to 190 keV. Semi-automated segmentation with threshold inpainting was used to obtain the attenuation values and standard deviation (SD) of the streak artefact. High contrast line pair resolution and background noise were assessed using the Catphan 500. Streak artefact is progressively reduced with increasing keV monoenergetic reconstructions. Reconstruction of a 400 mA acquisition at 150 keV results in reduction in the volume of streak artefact from 65 cm{sup 3} to 17 cm{sup 3} (74 %). There was a decrease in the contrast to noise ratio (CNR) at higher tube voltages, with the peak CNR seen at 70-80 keV. High contrast spatial resolution was maintained at high keV values. Monoenergetic reconstruction of dual energy CT at increasing theoretical kilovoltages reduces the streak artefact produced by beam hardening from orthopaedic prostheses, accompanied by a modest increase in heterogeneity of background image attenuation, and decrease in contrast to noise ratio, but no deterioration in high contrast line pair resolution. (orig.)

Electron beam generation in the fore-vacuum pressure range

CERN Document Server

Burachevskij, Y A; Kuzemchenko, M N; Mytnikov, A V; Oks, E M

2001-01-01

One presents the results of investigations to generate electron beams within 0.01-0.1 Torr gas pressure range. To generate a beam one used a plasma source based on a hollow cathode discharge in combination with a plane accelerating gap. Peculiar features of electron emission and acceleration within the mentioned pressure range are associated with high probability of gas ionization in an accelerating gap and with generation of ion flow meeting electron beam. It results in reduction of discharge combustion intensification, as well as, in plasma concentration range. The developed design of an electron source enables to generate cylindrical beams with up to 1 A current and with up to 10 keV energy

First experiments with the 200 keV electron beam ion trap at LLNL

International Nuclear Information System (INIS)

Marrs, R.E.; Knapp, D.A.; Elliott, S.

1993-01-01

A high-energy electron beam ion trap (Super EBIT) is operating at electron energies up to 200 keV and currents up to 200 mA. Highly charged ions up to Li-like U 89+ and H-like Pb 81+ have been produced and studied. Ionization cross sections for H-like Dy 66+ at E e = 170 keV have been measured with respect to radiative recombination from the observed Dy 66+ /Dy 67+ equilibrium ionization balance. A Bragg crystal spectrometer has been used to measure 2s 1/2 -2p 3/2 transition energies in Li-like U 82+ with respect to the Lymann-series transitions in lower-Z hydrogenic ions

A 7.2 keV spherical x-ray crystal backlighter for two-frame, two-color backlighting at Sandia's Z Pulsed Power Facility

Science.gov (United States)

Schollmeier, M. S.; Knapp, P. F.; Ampleford, D. J.; Harding, E. C.; Jennings, C. A.; Lamppa, D. C.; Loisel, G. P.; Martin, M. R.; Robertson, G. K.; Shores, J. E.; Smith, I. C.; Speas, C. S.; Weis, M. R.; Porter, J. L.; McBride, R. D.

2017-10-01

Many experiments on Sandia National Laboratories' Z Pulsed Power Facility—a 30 MA, 100 ns rise-time, pulsed-power driver—use a monochromatic quartz crystal backlighter system at 1.865 keV (Si He α ) or 6.151 keV (Mn He α ) x-ray energy to radiograph an imploding liner (cylindrical tube) or wire array z-pinch. The x-ray source is generated by the Z-Beamlet laser, which provides two 527-nm, 1 kJ, 1-ns laser pulses. Radiographs of imploding, thick-walled beryllium liners at convergence ratios CR above 15 [ C R = r i ( 0 ) / r i ( t ) ] using the 6.151-keV backlighter system were too opaque to identify the inner radius r i of the liner with high confidence, demonstrating the need for a higher-energy x-ray radiography system. Here, we present a 7.242 keV backlighter system using a Ge(335) spherical crystal with the Co He α resonance line. This system operates at a similar Bragg angle as the existing 1.865 keV and 6.151 keV backlighters, enhancing our capabilities for two-color, two-frame radiography without modifying the system integration at Z. The first data taken at Z include 6.2-keV and 7.2-keV two-color radiographs as well as radiographs of low-convergence (CR about 4-5), high-areal-density liner implosions.

Mass attenuation coefficient of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using 16.59 – 25.26 keV photon energy range

Energy Technology Data Exchange (ETDEWEB)

Mohd Yusof, Mohd Fahmi, E-mail: mfahmi@usm.my; Hamid, Puteri Nor Khatijah Abdul; Tajuddin, Abdul Aziz [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Bauk, Sabar [School of Distance Education, Universiti Sains Malaysia, 11800 Penang (Malaysia); Hashim, Rokiah [School of Industrial Technologies, Universiti Sains Malaysia, 11800 Penang (Malaysia)

2015-04-29

The Rhizophora spp. particleboards were fabricated using ≤ 104 µm particle size at three different fabrication methods; binderless, steam pre-treated and tannin-added. The mass attenuation coefficient of Rhizophora spp. particleboards were measured using x-ray fluorescent (XRF) photon from niobium, molybdenum, palladium, silver and tin metal plates that provided photon energy between 16.59 to 25.26 keV. The results were compared to theoretical values for water calculated using photon cross-section database (XCOM).The results showed that all Rhizophora spp. particleboards having mass attenuation coefficient close to calculated XCOM for water. Tannin-added Rizophora spp. particleboard was nearest to calculated XCOM for water with χ2 value of 13.008 followed by binderless Rizophora spp. (25.859) and pre-treated Rizophora spp. (91.941)

Mass attenuation coefficient of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using 16.59 – 25.26 keV photon energy range

International Nuclear Information System (INIS)

Mohd Yusof, Mohd Fahmi; Hamid, Puteri Nor Khatijah Abdul; Tajuddin, Abdul Aziz; Bauk, Sabar; Hashim, Rokiah

2015-01-01

The Rhizophora spp. particleboards were fabricated using ≤ 104 µm particle size at three different fabrication methods; binderless, steam pre-treated and tannin-added. The mass attenuation coefficient of Rhizophora spp. particleboards were measured using x-ray fluorescent (XRF) photon from niobium, molybdenum, palladium, silver and tin metal plates that provided photon energy between 16.59 to 25.26 keV. The results were compared to theoretical values for water calculated using photon cross-section database (XCOM).The results showed that all Rhizophora spp. particleboards having mass attenuation coefficient close to calculated XCOM for water. Tannin-added Rizophora spp. particleboard was nearest to calculated XCOM for water with χ2 value of 13.008 followed by binderless Rizophora spp. (25.859) and pre-treated Rizophora spp. (91.941)

Energy imparted to water slabs by photons in the energy range 5-300 keV. Calculations using a Monte Carlo photon transport model

International Nuclear Information System (INIS)

Persliden, J.; Carlsson, G.A.

1984-01-01

In diagnostic examinations of the trunk and head, the energy imparted to the patient is related to the radiation risk. In this work, the energy imparted to laterally infinite, 10-300 mm thick water slabs by 5-300 keV photons is calculated using a Monte Carlo photon transport model. The energy imparted is also derived for energy spectra of primary photons relevant to diagnostic radiology. In addition to values of energy imparted, values of backscattered and transmitted energies, quantities primarily obtained in the transport calculations, are reported. Assumptions about coherent scattering are shown to be important for values of backscattered and transmitted energies but unimportant with respect to values of energy imparted. Comparisons are made with other Monte Carlo results from the literature. Discrepancies of 10-20% in some calculated quantities can be traced back to the use of different tabulations of interaction cross-sections by various authors. (author)

Dipole stabilizer rods for 400 keV deuteron RFQ

International Nuclear Information System (INIS)

Sista, V.L.S. Rao; Srivastava, S.C.L.; Pande, Rajni; Roy, Shweta; Singh, P.

2009-01-01

In our 400 keV deuteron RFQ for neutron production, the destructive dipolar modes are very close to the required quadrupolar mode. In order to increase the spacing between the quadrupole and dipole modes the dipolar stabilizer rods (DSR's) are used. The design of the DSR's is done using the computer code CST Microwave studio. The variation of the quadrupole and dipolar mode frequencies with the radius and length of the DSR's are studied. (author)

Heavy concerns about the light axino explanation of the 3.5 keV X-ray line

CERN Document Server

Colucci, Stefano; Staub, Florian; Ubaldi, Lorenzo

2015-09-05

An unidentified 3.5 keV line from X-ray observations of galaxy clusters has been reported recently. Although still under scrutiny, decaying dark matter could be responsible for this signal. We investigate whether an axino with a mass of 7 keV could explain the line, keeping the discussion as model independent as possible. We point out several obstacles, which were overlooked in the literature, and which make the axino an unlikely candidate.

Mass attenuation coefficients in the range 3.8⩽E⩽11 keV, K fluorescence yield and Kβ/Kα relative X-ray emission rate for Ti, V, Fe, Co, Ni, Cu and Zn measured with a tunable monochromatic X-ray source

Science.gov (United States)

Ménesguen, Y.; Lépy, M.-C.

2010-08-01

This work presents new measurements of mass attenuation coefficients in the range 3.8⩽E⩽11 keV, K-absorption jump-ratios, Kα and Kβ fluorescence yields for Ti, V, Fe, Co, Ni, Cu and Zn. We use the experimental facility SOLEX, a tunable monochromatic X-ray source combined with an energy-dispersive high-purity germanium detector. The results are compared with theoretical values as well as with other experimental data and show a relatively good agreement. However, the derived K-jump-ratios appear larger than those widely used in the XCOM database. The Kα and Kβ fluorescence yields and the corresponding relative emission rates Kβ/Kα are also derived, which was made possible by the use of energy-dispersive detectors with good spectral resolution.

Effect of dose on the evolution of cavities in 500-KeV 4He+-ion irradiated nickel

International Nuclear Information System (INIS)

Fenske, G.; Das, S.K.; Kaminsky, M.; Miley, G.H.

1979-01-01

Transmission electron microscopy has been used to investigate the effect of total dose on the depth distribution of cavities (voids or bubbles) in nickel irradiated at 500 0 C with 500-keV 4 He + ions. A transverse sectioning technique, which allows one to obtain the entire depth distribution of cavities and of damage from a single specimen, was utilized. The size, number density and volume fraction of bubbles or voids were measured from the micrographs taken from samples sectioned parallel to the direction of the incident beam. The results for the dose range studied (2 x 10 19 to 1 x 10 21 ions/m 2 ) show that the average cavity diameter, number density, and the volume fraction (i.e., swelling) increases with increasing dose. The peak in the swelling distribution occurs at depths 8 to 15% deeper than the peak in the calculated projected range profile

Determination of the molecular structure via the medium energy electrons (500 eV-1,5 KeV) Ar, N2, Co e HCl

International Nuclear Information System (INIS)

Nogueira, J.C.

1977-01-01

Elastic Differential and Total Differential Cross Sections are measured for electron collision in medium-energy range (500 eV - 1,5 KeV) with argon, nitrogen, carbon monoxide and hydrogen chloride, all in their electronic ground state. Theoretical calculation for the Elastic Differential Cross Sections by atoms were done employing Hartree-Fock-Clementy wave function, and making use of Partial Wave and WKBJ Methods. Exchange effect is included in the case of argon. Independent Atom Model, Half Molecule Model and a new model, the Ionic Model were utilized for the molecular calculations. The Ionic Model is suggested for the interaction between HCl and electrons. Inelastic Differential Cross Section were also computed, making use of the First Born Approximation and Hartree-Fock-Clementi wave function. It is also demonstrated, for the first time, that medium energy electrons (500 eV - 1,5 Kev) can be used to determine molecular structure parameters, in gas phase [pt

Origin of 30 approximately 100 keV protons observed in the upstream region of the earth's bow shock

International Nuclear Information System (INIS)

Terasawa, T.

1979-01-01

A Fermi-type acceleration model is constructed to explain the origin of energetic protons (30 approximately 100 keV) which have been observed upstream of the bow shock. It is shown that the suprathermal protons (with energy of several keV) can be accelerated up to several tens of keV through the Fermi-type process in which the reflection at the shock front and the scattering in the upstream region are coupled. The efficiency of the scattering process is estimated by using the results of Barnes' quasilinear treatment of the wave excitation. The resultant energy spectrum and flux intensity (10 3 approximately 10 4 protons/(cm 2 s ster keV) in 32 approximately 45.3 keV) are consistent with the observation, and the softening of the energy spectrum observed in the dawn region can be explained by the decrease in the efficiency of the acceleration process in the dawn region due to the curvature of the bow shock and the reduction of shock strength. The spatial distribution of the flux predicted by the model is also consistent with the observation. In view of these consistencies of the Fermi-type acceleration process is suggested as a possible candidate mechanism to explain the upstream protons although it is not intended to exclude other possibilities. (author)

Improved atomic data for electron-transport predictions by the codes TIGER and TIGERP: II. Electron stopping and range data

International Nuclear Information System (INIS)

Peek, J.M.; Halbleib, J.A.

1983-04-01

The electron stopping and range data now used in the TIGER and TIGERP electron-transport codes are extracted and compared with other data for these processes. At the smallest collision energies treated by these codes, E approx. 1 keV, the stopping-power is estimated to be accurate for small-Z targets, to be about 25 percent too small for Z near 36 and to be a factor of three too small for Z > 79. These errors decrease with increasing E and the largest error for any target is roughly 20 percent for E = 10 keV. The closely related continuous-slowing-down range is estimated, at 1 keV, to be about 25 percent too small for small-Z targets and a factor of 2 too large for large-Z targets. The electron-transport problem of reflection from planer surfaces is re-investigated with improved stopping-power data. The effects of this change for the examples considered were about the size of the statistical uncertainties in the calculation, 1 to 2 percent

X-ray attenuation cross sections for energies 100 eV to 100 keV and elements Z = 1 to Z = 92

International Nuclear Information System (INIS)

Saloman, E.B.; Hubbell, J.H.; Scofield, J.H.

1988-01-01

This work presents for the energy range 0.1--100 keV the National Bureau of Standards (NBS) database of experimental x-ray attenuation coefficients (total absorption cross sections) and cross sections calculated using a relativistic Hartree--Slater model for the photoelectric cross section for all elements of atomic number Z = 1--92. The information is displayed in both tabular and graphical form. Also shown on the graphs are cross sections obtained using the semiempirical set of recommended values of B. L. Henke and co-workers (Atomic Data and Nuclear Data Tables 27, 1 (1982)). A bibliography of the NBS database for this energy range is included. copyright 1988 Academic Press, Inc

RADIAL PROFILE OF THE 3.5 keV LINE OUT TO R 200 IN THE PERSEUS CLUSTER

International Nuclear Information System (INIS)

Franse, Jeroen; Bulbul, Esra; Bautz, Mark; McDonald, Michael; Miller, Eric; Foster, Adam; Randall, Scott W.; Smith, Randall K.; Boyarsky, Alexey; Markevitch, Maxim; Iakubovskyi, Dmytro; Ruchayskiy, Oleg; Loewenstein, Mike

2016-01-01

The recent discovery of the unidentified emission line at 3.5 keV in galaxies and clusters has attracted great interest from the community. As the origin of the line remains uncertain, we study the surface brightness distribution of the line in the Perseus cluster since that information can be used to identify its origin. We examine the flux distribution of the 3.5 keV line in the deep Suzaku observations of the Perseus cluster in detail. The 3.5 keV line is observed in three concentric annuli in the central observations, although the observations of the outskirts of the cluster did not reveal such a signal. We establish that these detections and the upper limits from the non-detections are consistent with a dark matter decay origin. However, absence of positive detection in the outskirts is also consistent with some unknown astrophysical origin of the line in the dense gas of the Perseus core, as well as with a dark matter origin with a steeper dependence on mass than the dark matter decay. We also comment on several recently published analyses of the 3.5 keV line.

Some early results of the keV plasma experiment on GEOS-1

International Nuclear Information System (INIS)

Borg, H.; Holmgren, L.-A.; Hultqvist, B.; Cambou, F.; Reme, H.

1978-01-01

Some preliminary new results are presented of the keV plasma experiment on GEOS-1. Electrons and ions have been observed to stream along the magnetic field lines in the dayside magnetosphere from the ionospheric side of the satellite towards the equatorial plane during magnetic storms, with streaming velocities corresponding to a kinetic energy of the order of a keV. The opposite streaming velocity has also been seen, but primarily in the ions only and with a smaller flux ratio for the two opposite directions along the field lines. The transition between the two opposite streaming directions, as seen by the satellite, has been found to occur even in a fraction of a second. In magnetic storm conditions azimuthal asymmetries in ion fluxes corresponding to electric field intensities of several tens of millivolts per meter have been observed. (Auth.)

Evaluation of the 2039 keV level property in {sup 124}Te

Energy Technology Data Exchange (ETDEWEB)

Katakura, J. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-03-01

One of the purposes of the mass chain evaluation is to provide reliable level properties of isobars based on available experimental data. In the work of A=124 mass chain evaluation, we have faced some confusing data relating to confirming the level properties of the 2039 keV level in {sup 124}Te: (1) inconsistent intensity ratios of emitted gamma rays between reaction gamma ray and decay gamma ray data, (2) placement of 2039 keV gamma ray transition and (3) gamma ray angular correlation data relating to the level. In the evaluation work, we have to reconcile the confusing data and to provide the adopted ones derived from the available data. In this report, the problems relating to the level properties are described and the reanalyses of the measured data are presented for providing the adopted data. (author)

Existence of Mott-Schwinger interaction proved by means of p-/sup 12/C elastic scattering. [450 to 600 keV

Energy Technology Data Exchange (ETDEWEB)

Krause, H H; Arnold, W; Berg, H; Ulbricht, J; Clausnitzer, G [Giessen Univ. (Germany, F.R.). Inst. fuer Kernphysik

1979-01-01

The aim of this work was the unambiguous proof of the existence of the Mott-Schwinger interaction. The analyzing power of the p-/sup 12/C elastic scattering was measured in the energy range from 450 to 600 keV for scattering angles theta/sub Lab/ = 90/sup 0/ and 120/sup 0/ with an overall accuracy up to ..delta..A = 1 x /sup -4/. The data can be described very well with the R-matrix formalism including Mott-Schwinger interaction. Omitting this interaction results in large discrepancies.

Lasten ulkovaatteiden kevät-kesämalliston seinäesillepano-ohje : case: Reima Oy

OpenAIRE

Järvenoja, Annika

2014-01-01

Opinnäytetyö tehtiin Reima Oy:lle. Työn tavoitteena oli kerätä asiakkaiden mielipiteitä lasten ulkovaatteiden seinäesillepanoista. Tutkimuksen pohjalta tehtiin seinäesillepano-ohje kevät-kesämallistolle. Reiman omat myymälät sijaitsevat pääosin Kiinassa, Suomessa ja Venäjällä. Kevät-kesämalliston tuotteiden vaihtelevuus välikausivaatteista ohuisiin aurinkosuojavaatteisiin koettiin myymälässä haasteelliseksi. Tavoitteena on tutkia lisäksi, mistä maiden kulttuurien eroavaisuudet johtuvat, ja mi...

Total internal conversion coefficient of the 260. 9 keV (7/sup +/->3/sup -/) transition in sup(198m)Tl

Energy Technology Data Exchange (ETDEWEB)

Venkateswara Rao, N.; Suryanarayana, C.; Narayana, D.G.S.; Bhuloka Reddy, S.; Satynarayana, G.; Sastry, D.L.; Chintalapudi, S.N.

1986-02-21

The 1.87 hours 543.7 keV (7/sup +/) isomeric state in /sup 198/Tl is produced via /sup 197/Au(..cap alpha.., 3n)sup(198m)Tl (Esub(..cap alpha..) = 35 MeV) reaction. The total conversion coefficient of 260.9 keV (7/sup +/ -> 3/sup -/) is determined for the first time by the intensity balance method. The value of ..cap alpha..sub(T)(260.9 keV) is found to be 40.1 +- 8.6 which is in good agreement with the theoretical value of Hager and Seltzer for pure M4 transition. The gamma transition probability of the 260.9 keV (M4) is calculated using the present value of ..cap alpha..sub(T) and compared with the single-particle estimate.

Development of an X-ray imaging system within 10-30 keV spectral range based on organic or inorganic scintillator

International Nuclear Information System (INIS)

Turk, G.

2011-01-01

This thesis aims at developing an x-ray imaging system intended for the Laser Mega Joule, within the framework of Inertial Confinement Fusion (ICF) experiments. ICF aims at yielding thermonuclear energy through laser-driven fusion of a deuterium-tritium mix. The operational function of our system is to acquire an image of the 10-30 keV x-rays emitted by the maximally compressed micro-balloon, with spatial resolution better than 10 μm. The presented system is only a part of a complete diagnostic system, which normally includes an x-ray optical subsystem. Our system conception largely takes vulnerability into account. The ignition phase of ICF yields 10 16 neutrons, with energies scaling up to 14 MeV. The neutrons generate such a hard surrounding with effects scaling down from image degradation up to instrumentation destruction. The presented system consists in a scintillator which is focused on a CCD camera through a catadioptric image transport system. An innovation work has been lead on scintillators to provide an answer to specifications greatly influenced by vulnerability. Those thesis works lead to an imaging system allowing to deport the CCD camera by 4 meters from the scintillator, with 100 μm spatial resolution in the scintillator plane. Those works have paved the way to outlooks such as enhancement of organic loaded scintillators compositions and improvement of optical relay system. (author) [fr

Kirkpatrick-Baez microscope with spherical multilayer mirrors around 2.5keV photon energy

Science.gov (United States)

An, Ning; Du, Xuewei; Wang, Qiuping; Cao, Zhurong; Jiang, Shaoen; Ding, Yongkun

2014-09-01

A Kirkpatrick-Baez (KB) x-ray microscope has been developed for the diagnostics of inertial confinement fusion (ICF). The KB microscope system works around 2.5keV with the magnification of 20. It consists of two spherical multilayer mirrors. The grazing angle is 3.575° at 2.5keV. The influence of the slope error of optical components and the alignment errors is simulated by SHADOW software. The mechanical structure which can perform fine tuning is designed. Experiment result with Manson x-ray source shows that the spatial resolution of the system is about 3-4μm over a field of view of 200μm.

3-10 keV and 0.1- to 2-MeV observations of four gamma-ray bursts

International Nuclear Information System (INIS)

Laros, J.G.; Evans, W.D.; Fenimore, E.E.; Klebesadel, R.W.; Shulman, S.; Fritz, G.

1983-01-01

Four catalogued γ-ray bursts that occurred between 79/3/7 and 79/7/31 have been observed over the 3 to 10 keV range by a joint NRL/Los Alamos experiment on the Air Force P78-1 satellite. The bursts were also well observed by members of the interplanetary network. In this paper we present hardness ratios, x-ray/γ-ray luminosity ratios, and time histories. The most significant results presented herein can be summarized as follows: (1) gamma-ray bursters can emit fairly strongly at x-ray energies near the time of the γ burst with L/sub x//L/sub γ/ approx. .02 (L/sub x/ approx. 10 37 ergs s -1 , 3 to 10 keV, assuming a distance of 1 kpc); (2) the centroid of the x-ray emission generally lags the γ-ray centroid, but there is also evidence for one or more types of x-ray precursor activity; (3) the γ-ray hardness ratios were not highly variable for these particular events. However, there is some evidence that the γ-ray spectra softened near the ends of the bursts when the x-ray/γ-ray ratios were high; (4) the x-ray/γ-ray power law number index during times of the strongest γ-ray emission ranged from 0.8 to approx. 1.1 for the four bursts; (5) the x-ray tail of GB790307 probably can be modeled as the cooling of hot plasma generated during the γ-ray burst. Simple versions of this model can be used to estimate various source parameters. These estimates imply a distance of a few hundred to a few thousand pc; (6) gamma-ray bursters probably do not produce events similar to classical x-ray bursts independently of the γ-ray emission

Properties of the Plasma Surrounding the Global Heliosphere Determined with Voyager 1&2 ions and ENA/INCA Observations at E > 5 keV

Science.gov (United States)

Krimigis, S. M.; Dialynas, K.; Mitchell, D. G.; Decker, R. B.; Roelof, E. C.

2016-12-01

The basic goal of the proposed Interstellar Mapping and Acceleration Probe (IMAP) is detailed scientific understanding of the Heliosheath (HS) and beyond, a region of space explored in situ by Voyager 1 (V1) since 2004, Voyager 2 (V2) since 2007, and remotely via energetic neutral atoms (ENA) by the Cassini/INCA (5.2-55 keV) since 2003 and IBEX (0.3-6 keV) since 2009. The partial overlap in energies (28 5 keV, the rest residing below that range, resulting in a beta (particle/magnetic pressure) always > 1, typically >10. (2) Based on the ENA-derived hot ion pressures, the interstellar magnetic field (ISMF) was predicted to be more than twice that expected in the literature i.e. similar to what was measured by V1 after crossing the heliopause (B 0.5 nT). (3) The width of the HS in the direction of V1 is 30 AU (predicted by INCA before the V1 HP crossing), but is thought to be larger (40-70 AU) in the southern ecliptic where V2, now 30 AU into the HS, currently travels. We address here the key question of the source of 5-55 keV ENAs that INCA measures. The analysis of INCA all-sky maps from 2003 to 2014 show that the decrease and recovery of ENA in the global heliosphere during this period (declining phase of SC23 and rise of SC24) is similar to that of the ions at V1/V2, consistent with the HS ions being the source of ENA. The close correspondence between ENA and ion spectra (despite the 140 AU distance between V1 and V2) as well as the similarity of ENA spectra over the nose and anti-nose directions, together with the recent V1 measurement of a BISMF 0.5nT, suggest that the global distributions of >5 keV ions in the heliosheath resembles a diamagnetic bubble with no significant tail-like feature (the alternative Parker 1961 model), also consistent with some recent MHD simulations and models.

The Galactic 511 keV line: analysis and interpretation of Integral observations; L'annihilation des positrons galactiques: analyse et interpretation des donnees INTEGRAL

Energy Technology Data Exchange (ETDEWEB)

Lonjou, V

2005-09-15

Ever since the discovery of the 511 keV annihilation line emission from the galactic center region in the late seventies, the origin of galactic positrons has been the topic of a vivid scientific debate. It is also one of the prime scientific objectives of the imaging spectrometer SPI on board ESA's INTEGRAL observatory. In this thesis first a description of the most important SPI sub-system is given - the detector plane. Procedures for detector energy calibration and detector degradation analysis are developed. The determination of instrumental background models, a crucial aspect of data analysis, is elaborated. These background models are then applied to deriving sky maps and spectra of unprecedented quality of the Galactic positron annihilation radiation. The emission is centered on the galactic center with a spatial resolution of 8 degrees (FWHM), a second spatial component appears clearly: the galactic disc. The ray energy has been measured with unprecedented accuracy: 511.0 {+-} 0.03 keV for a full width at half maximum (FWHM) of 2.07 {+-} 0.1 keV. The total galactic flux ranges from 1.09 to 2.43 10{sup -3} ph.cm{sup -2}.s{sup -1} including uncertainties on spatial distribution. Finally, the implications of these observations for the production of positrons by various Galactic populations are discussed.

K-capture probabilities to 400. 56 and 279. 48 keV levels in the decay of /sup 75/Se

Energy Technology Data Exchange (ETDEWEB)

Singh, K; Sahota, H S

1984-02-01

Precisely calibrated high resolution intrinsic semiconductor detector has been used to find K-capture probabilities to 400.56 and 279.48 keV levels in the decay of /sup 75/Se. The measurement to 279.48 keV level is reported for the first time in literature.

Electron transfer in keV Li+-Na(3s, 3p) collisions: I. Atomic basis coupled-channel calculations

International Nuclear Information System (INIS)

Nielsen, S.E.; Dubois, A.

1995-01-01

Integral cross sections for electron capture from the ground state Na(3s) and excited states Na(3p) to Li(nlm), n = 2, 3, are calculated by the semiclassical impact-parameter method, using a two-centre atomic basis expansion. In the impact energy range 1-50 keV, results are analysed with particular emphasis on the alignment and orientation of initial and final p-states. At intermediate velocities opposite initial alignment effects are found for capture to n = 2 and n = 3 states, respectively. Orientation effects in state-to-state capture cross sections are predicted from oriented and tilted aligned initial states. (Author)

Atomic scattering in the diffraction limit: electron transfer in keV Li+-Na(3s, 3p) collisions

DEFF Research Database (Denmark)

Poel, Mike van der; Nielsen, C.V.; Rybaltover, M.

2002-01-01

We measure angle differential cross sections (DCS) in Li+ + Na --> Li + Na+ electron transfer collisions in the 2.7-24 keV energy range. We do this with a newly constructed apparatus which combines the experimental technique of cold target recoil ion momentum spectroscopy with a laser-cooled target...... of the de Broglie wavelength lambda(dB) = 150 fm at a velocity v = 0.20 au and the effective atomic diameter for electron capture 2R = 20 au. Parallel AO and MO semiclassical coupled-channel calculations of the Na(3s, 3p) --> Li(2s, 2p) state-to-state collision amplitudes have been performed, and quantum...

Energy dependence of effective atomic numbers for photon energy absorption and photon interaction: Studies of some biological molecules in the energy range 1 keV-20 MeV

DEFF Research Database (Denmark)

Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

2008-01-01

Effective atomic numbers for photon energy absorption, Z(PEA,eff), and for photon interaction, Z(PI,eff), have been calculated by a direct method in the photon-energy region from 1 keV to 20 MeV for biological molecules, such as fatty acids (lauric, myristic, palmitic, stearic, oleic, linoleic......, linolenic, arachidonic, and arachidic acids), nucleotide bases (adenine, guanine, cytosine, uracil, and thymine), and carbohydrates (glucose, sucrose, raffinose, and starch). The Z(PEA, eff) and Z(PI, eff) values have been found to change with energy and composition of the biological molecules. The energy...

1974 view into the cage of the 520 keV electrostatic preaccelerator of Linac 1

CERN Multimedia

1974-01-01

The condenser of the high voltage circuit (column in the foreground) is being serviced by Jean Luc Vallet. Standing on the electronics platform (the big, open metallic structure on insulating pillars, for details see 7403120) is Bob Nettelton. The column at the right edge of the photo is part of the bouncer (see also 7403066X) which compensated the voltage drop during acceleration of a proton pulse. In the background is the source (open pill box structure) attached to the accelerating column, barely visible) behind. The "old" 50 MeV Linac 1, the original PS injector built in the 1950s, was (since 1976) replaced by a new 50 MeV linac (Linac 2) with a 750 keV "Cockcroft-Walton" pre-injector(see 7602012X), later replaced by a 750 keV Radio Frequency Quadrupole (RFQ) preaccelerator. Linac 1 co-existed until mid 1992 (from 1982 onwards it was mainly used to inject "test-particles" into the Low Energy Antiproton ring LEAR). In 1984 the electrostatic preaccelerator of linac 1 was replaced by a 520 keV RFQ ( 8303511X...

Two-dimensional analysis of three-body reactions 11B(p,αα) from 163 keV to MeV

International Nuclear Information System (INIS)

Engelhardt, D.; Fontenille, J.

1967-01-01

An experimental apparatus for two-dimensions analysis of the break-up of 12 C * produced by the reaction 11 B(p,αα) 4 He, at proton bombarding energies between 163 keV and 2 MeV, is described. It uses Si surface barrier detectors and, fast-slow coincidence techniques: the energy resolution is about 40 keV and time resolution 6 ns. A 4096 channel analyser and a small digital computer was used for information storage and data processing. The experimental set-up was tested on the C.E.N.G. 2 MeV Van de Graaff accelerator. The spectra of the 12 C * decay products taken at proton bombarding energies of 163 keV and 680 keV at different angles between the two α-counters are shown. They indicate strong evidence for sequential decay of 12 C * to the 8 Be fundamental, first or second excited level. (authors) [fr

Interferometric phase-contrast X-ray CT imaging of VX2 rabbit cancer at 35keV X-ray energy

Science.gov (United States)

Takeda, Tohoru; Wu, Jin; Tsuchiya, Yoshinori; Yoneyama, Akio; Lwin, Thet-Thet; Hyodo, Kazuyuki; Itai, Yuji

2004-05-01

Imaging of large objects at 17.7-keV low x-ray energy causes huge x-ray exposure to the objects even using interferometric phase-contrast x-ray CT (PCCT). Thus, we tried to obtain PCCT images at high x-ray energy of 35keV and examined the image quality using a formalin-fixed VX2 rabbit cancer specimen with 15-mm in diameter. The PCCT system consisted of an asymmetrically cut silicon (220) crystal, a monolithic x-ray interferometer, a phase-shifter, an object cell and an x-ray CCD camera. The PCCT at 35 keV clearly visualized various inner structures of VX2 rabbit cancer such as necrosis, cancer, the surrounding tumor vessels, and normal liver tissue. Besides, image-contrast was not degraded significantly. These results suggest that the PCCT at 35 KeV is sufficient to clearly depict the histopathological morphology of VX2 rabbit cancer specimen.

Experimental charge fractions of hydrogen scattered from insulators at 50-340 keV

CERN Document Server

Ross, Graham G

2002-01-01

Ion bombardment of insulators induces accumulation of electric charges at and under the insulator surfaces. This paper deals with the effect of the accumulated electric charges on the charge fractions of scattered hydrogen. We have measured and compiled charge fractions of hydrogen, in the energy range (for the scattered particles) from 50 to 340 keV, scattered from polystyrene, polymethylmethacrylate, polycarbonate, polyethylene and silicon. In order to establish the effect of the charge accumulation, some samples have been cut from a thick (1 mm) sheet, while some others have been spin coated (approx 250 nm) onto silicon wafers. Experimental measurements have been fitted with the equation f(0)=Aexp(-V sup 2 /V sub i V sub 0), where f(0) is the neutral fraction, V the velocity, V sub i the 'Bohr velocity' for the electron of projectiles, A and V sub 0 the fitting parameters. Comparisons using the least-square fitting procedure have shown that the accumulation of electric charges on the thick polymer samples ...

CSR: a new tool for storage and cooling of keV ion beams

Energy Technology Data Exchange (ETDEWEB)

Froese, Michael; Blaum, Klaus; Crespo Lopez-Urrutia, Jose; Fellenberger, Florian; Grieser, Manfred; Kaiser, Dirk; Lange, Michael; Laux, Felix; Menk, Sebastian; Orlov, Dmitry A.; Repnow, Roland; Schroeter, Claus D.; Schwalm, Dirk; Sieber, Thomas; Ullrich, Joachim; Varju, Jozef; Hahn, Robert von; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Heber, Oded; Rappaport, Michael; Toker, Jonathan; Zajfman, Daniel [Weizman Institute of Science, Rehovot (Israel)

2009-07-01

An electrostatic Cryogenic Storage Ring (CSR) is currently being built in Heidelberg, Germany. The current status and final design of this ring, with a focus on the optimized 2 K chamber cooling, precision chamber suspension, and pumping down to extremely low pressures via cryogenic vacuum chambers will be presented. This ring will allow long storage times of highly charged ion and polyatomic molecular beams with energies in the range of keV per charge-state. Combining the long storage times with vacuum chamber temperatures approaching 2 K, infrared-active molecular ions will be radiatively cooled to their rotational ground states. Many aspects of this concept were experimentally tested with a cryogenic trap for fast ion beams (CTF), which has already demonstrated the storage of fast ion beams in a large cryogenic device. An upcoming test will investigate the effect of pre-baking the cryogenic vacuum chambers to 600 K on the cryogenic vacuum and the ion beam storage.

Short-range order in InSb amorphized under ion bombardment

International Nuclear Information System (INIS)

Pavlov, P.V.; Tetel'baum, D.I.; Gerasimov, A.I.

1979-01-01

The investigation of short-range order is carried out in polycrystal InSb films, irradiated with Ne + ions with E=150 keV and with the 2x10 15 ion/cm 2 dose. The data are obtained testifying to the film amorphization, the cause of which is the defect storage but not the local melting. Stability of the obtained amorphous phase at the room temperature is noted

Wide Range Portable Radiation Survey Meter for Emergency Monitoring

Energy Technology Data Exchange (ETDEWEB)

Gangadharan, P.; Bhave, D. G.; Gokarn, R. S.; Khadake, R. G. [Directorate Of Radiation Protection, Bhabha Atomic Research Centre, Trombay, Bombay (India)

1969-05-15

The paper describes a portable battery-operated radiation survey meter for monitoring a wide range of X- and gamma-ray exposure rates from 1 mR/h to 100 R/h. The instrument Incorporates a halogen GM tube as the detector and a count-rate meter for indication. A transistorized d.c. -d.c. converter supplies the necessary high voltage to the GM counter. The instrument response has been made energy independent in the energy range 80 keV to 1.25 MeV. Further, the response is linear over the entire range of exposure rates. Suitable extension rods have been designed to provide sufficient separation between the probe and the meter in cases where remote monitoring is necessary because of high fields. (author)

100 keV 10-B+ implantation into poly-(di-n-hexyl silane), (PDHSi)

International Nuclear Information System (INIS)

Fink, D.; Mueller, M.; Behar, M.; Papaleo, R.M.

2006-01-01

100 keV 10 B + ions were implanted into poly-(di-n-hexyl silane) in different directions at a fluence of 1 x 10 14 cm -2 , and their depth distribution was determined by means of the neutron depth profiling technique. In no case were the projectile ions found to come to rest according to their predicted range profiles. Instead, they are always found to undergo considerable long-range migration. During the irradiation process this motion appears to be radiation-enhanced, and during the subsequent annealing steps one appears to deal with regular thermal diffusion. The implant redistribution is always found to be governed strongly by the self-created damage, insofar as both electronic and nuclear defects in the polymer act as trapping centers. Their population ratio is modified by thermal annealing. The as-implanted redistribution shows a pronounced directional dependence, which essentially is a consequence of the spatial distributions of the electronic and nuclear damage. The changes of the nuclear defect distribution during thermal annealing are studied by a specially developed tomographic method. It is found that boron is preferentially trapped along the irradiation direction, exhibiting quite pronounced prolate (i.e. cigar-like) distributions. This shape is almost unaffected by thermal annealing. (orig.)

Tuning of wettability of PANI-GNP composites using keV energy ions

Energy Technology Data Exchange (ETDEWEB)

Lakshmi, G.B.V.S., E-mail: lakshmigbvs@gmail.com [Inter University Accelerator Centre, New Delhi 67 (India); Avasthi, D.K. [Amity University, Noida 201313, Uttar Pradesh (India)

2016-07-15

Polyaniline nanofiber composites with various nanomaterials have several applications in electrochemical biosensors. The surface properties of these composites coated electrodes play crucial role in enzyme absorption and analyte detection process. In the present study, Polyaniline-Graphene nanopowder (PANI-GNP) composites were prepared by rapid-mixing polymerization method. The films were prepared on ITO coated glass substrates and irradiated with 42 keV He{sup +} ions produced by indigenously fabricated accelerator at IUAC, New Delhi. The films were characterized before and after irradiation by SEM, Raman spectroscopy and contact angle measurements. The as-prepared films show superhydrophilic nature and after irradiation the films show highly hydrophobic nature with water contact angle (135°). The surface morphology was studied by SEM and structural changes were studied by Raman spectra. The surface morphological modifications induced by keV energy ions helps in tuning the wettability at different ion fluences.

Iodine-131 imaging using 284 keV photons with a small animal CZT-SPECT system dedicated to low-medium-energy photon detection.

Science.gov (United States)

Kojima, Akihiro; Gotoh, Kumiko; Shimamoto, Masako; Hasegawa, Koki; Okada, Seiji

2016-02-01

Iodine-131 is widely used for radionuclide therapy because of its β-particle and for diagnostic imaging employing its principal gamma ray. Since that principal gamma ray has the relatively high energy of 364 keV, small animal single-photon emission computed tomography (SPECT) imaging systems may be required to possess the ability to image such higher energy photons. The aim of this study was to investigate the possibility of imaging I-131 using its 284 keV photons instead of its 364 keV photons in a small animal SPECT imaging system dedicated to the detection of low-medium-energy photons (below 300 keV). The imaging system used was a commercially available preclinical SPECT instrument with CZT detectors that was equipped with multi-pinhole collimators and was accompanied by a CT imager. An energy window for I-131 imaging was set to a photopeak of 284 keV with a low abundance compared with 364 keV photons. Small line sources and two mice, one of each of two types, that were injected with NaI-131 were scanned. Although higher counts occurred at the peripheral region of the reconstructed images due to the collimator penetration by the 364 keV photons, the shape of the small line sources could be well visualized. The measured spatial resolution was relatively poor (~1.9 mm for full width at half maximum and ~3.9 mm for full width at tenth maximum). However, a good linear correlation between SPECT values and the level of I-131 radioactivity was observed. Furthermore, the uptake of NaI-131 to the thyroid gland for the two mice was clearly identified in the 3D-SPECT image fused with the X-ray CT image. We conclude that the use of an energy window set on the photopeak of 284 keV and the multi-pinhole collimator may permit I-131 imaging for a preclinical CZT-SPECT system that does not have the ability to acquire images using the 364 keV photons.

LUCIA - a new 1-7 keV μ-XAS Beamline

International Nuclear Information System (INIS)

Janousch, M.; Schmidt, Th.; Wetter, R.; Grolimund, G.; Scheidegger, A.M.; Flank, A.-M.; Lagarde, P.; Cauchon, G.; Bac, S.; Dubuisson, J.M.

2004-01-01

LURE-SOLEIL (France) and the Swiss Light Source (SLS) are building together a new micro focused beamline for micro x-ray absorption spectroscopy and micro imaging. This line is designed to deliver a photon flux of the order of 1012 ph/sec on a 1 x 1 μm spot within the energy domain of 0.8 to 7 keV. This beam line is being installed on the X07M straight section of SLS. The source is an APPLE II undulator with a period of 54 mm. The main advantage of this device lies in the delivery of any degree of polarization, linear or circular, over the whole energy range, without the need of a sample-position change. The monochromator will be a fixed exit double crystal equipped with 5 sets of crystals, thanks to the very narrow photon beam from the undulator ( Beryl, KTP, YB66, InSb(111), Si(111) ). The optics includes a first horizontal focusing mirror (spherical), which produces an intermediate source for the horizontal mirror of a Kirkpatrick-Baez (KB) system. The vertical mirror of the KB directly images the source. Finally, a low-pass double mirror filter insures a proper harmonic rejection

Cryogenic trapping of keV ion beams at the CSR prototype

Energy Technology Data Exchange (ETDEWEB)

Menk, Sebastian; Blaum, Klaus; Froese, Michael; Grieser, Manfred; Lange, Michael; Orlov, Dimitry; Sieber, Thomas; Hahn, Robert von; Varju, Jozef; Wolf, Andreas [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Heber, Oded; Rappaport, Michael; Zajfman, Daniel [Weizmann Institut of Science, Rehovot (Israel)

2009-07-01

A Cryogenic Trap for Fast ion beams (CTF) was built to explore cooling techniques and test thermal decoupling of ion optics for the development of the electrostatic Cryogenic Storage Ring (CSR). These challenging projects will lead to a new experimental field of atomic and molecular physics with keV ion beams. The cold conditions of 2-10 K minimize the blackbody radiation field and are expected to lead to extremely low restgas densities (equivalent pressure at room temperature {approx}10{sup -13} mbar) which result in long storage lifetimes and for molecular ions to radiative cooling to their ro-vibrational ground states. The CTF consists of two stacks of electrostatic mirror electrodes allowing the storage of up to 20 keV ion beams. Cryogenic ion beam storage has been realized with this device using a liquid helium refrigeration system to cool down the experimental trapping area to few-Kelvin cryogenic temperatures and experiments with cryogenically trapped molecular nitrogen ions have been performed to verify the low vacuum conditions by measuring their storage lifetimes.

Presence of neutrons in the low-level background environment estimated by the analysis of the 595.8 keV gamma peak

Energy Technology Data Exchange (ETDEWEB)

Anđelić, Brankica; Knežević, David; Jovančević, Nikola; Krmar, Miodrag; Petrović, Jovana; Toth, Arpad; Medić, Žarko; Hansman, Jan

2017-04-21

In order to explore possible improvements of the existing techniques developed to estimate the neutron fluence in low-background Ge-spectroscopy systems, gamma spectra were collected by a HPGe detector in the presence of the {sup 252}Cf spontaneous fission neutron source. The spectra were taken with and without a Cd envelope on the detector dipstick, with different thicknesses of plastic used to slow down neutrons. We have analyzed the complex 595.8 keV gamma peak, as well as several more gamma peaks following the neutron interactions in the detector itself and surroundings materials. The investigation shows that some changes of the initial neutron spectra can be monitored by the analysis of the 595.8 keV gamma peak. We have found good agreement in the intensity changes between the long-tail component of the 595.8 keV and the 691 keV gamma peak ({sup 72}Ge(n,n′){sup 72}Ge reaction), usually used for the estimation of the fast neutron fluence. Results also suggest that the thermal neutrons can have a stronger influence on creation of the Gaussian-like part of 595.8 keV peak, than on the 139 keV one following {sup 74}Ge(n,γ){sup 75m}Ge reaction and used in the standard methods (Škoro et al., 1992) [8] for determination of the thermal neutron flux.

Storm-associated variations of equatorially mirroring ring current protons, 1--800 keV, at constant first adiabatic invariant

International Nuclear Information System (INIS)

Lyons, L.R.; Williams, D.J.

1976-01-01

Explorer 45 observations of ring current protons mirroring near the equator, 1--800 keV, are presented at constant first adiabatic invariant μ throughout the period of the December 17, 1971, geomagnetic storm. To obtain μ, simultaneous magnetic field and particle observations are used. Particle deceleration in response to the storm time magnetic field decrease causes ring current measurements viewed at constant energy to underestimate the storm time increase in proton intensities at energies approximately-less-than200 keV. This adiabatic deceleration also accounts for the large flux decreases observed at energies approximately-greater-than200 keV during the storm, in contradiction with previous results (Soraas and Davis, 1968) obtained using a model for the storm time magnetic field

Pitch angle distributions of > 30 keV electrons at geostationary altitudes

International Nuclear Information System (INIS)

Higbie, P.R.; Baker, D.N.; Hones, E.W. Jr.; Belian, R.D.

1978-01-01

The satellites 1976-059A and 1977-007A each carry energetic particle detectors which measure fluxes of electrons in the 30 to 300 keV energy range. Five separate sensors mounted at 30, 60, 90, 120, and 150 0 to the spacecraft spin axis provide two hundred samples of the three dimensional distribution function for every ten second spacecraft rotation. Spherical harmonic functions up to the fourth order were fit to the observed pitch angle distributions. The second and fourth order coefficients obtained for these fits were averaged for each hour of local time. The probability distributions for the averaged harmonic coefficients were calculated and are presented as a function of local time. Possible relations of these distributions to interplanetary conditions are discussed. Using the present analysis techniques, the intensity of electrons at the noon meridian is derived as a function of pitch angle and radial distance and is given by j(α,r) = 2.03 x 10 8 (0.49 sin 4 . 78 α + 0.51 sin 0 . 27 α) e/sup -r/1.60/ el/cm 2 sec sr. 11 references

A high resolution reflecting crystal spectrometer to measure 3 keV pionic hydrogen and deuterium X-rays

International Nuclear Information System (INIS)

Badertscher, A.; Bogdan, M.; Goudsmit, P.F.A.; Knecht, L.; Leisi, H.J.; Schroeder, H.C.; Sigg, D.; Zhao, Z.G.; Chatellard, D.; Egger, J.P.; Jeannet, E.; Aschenauer, E.C.; Gabathuler, K.; Simons, L.M.; Rusi El Hassani, A.J.

1993-01-01

A reflecting crystal spectrometer consisting of three cylindrically bent quartz (110) crystals is described. It was designed to measure the 3 keV K β X-rays from pionic hydrogen and deuterium. Charge coupled devices (CCDs) were used as X-ray detectors. Projecting the reflexes of all three crystals on one common focus, an instrumental energy resolution below 1 eV was obtained at an energy of 2.9 keV. (orig.)

Detailed tabulation of atomic form factors, photoelectric absorption and scattering cross section, and mass attenuation coefficients in the vicinity of absorption edges in the soft X-ray (Z=30-36, Z=60-89, E=0.1 keV-10 keV), addressing convergence issues of earlier work

International Nuclear Information System (INIS)

Chantler, C.T.

2000-01-01

Reliable knowledge of the complex x-ray form factor [Re(f ) ] and the photoelectric attenuation coefficient (σ PE ) is required for crystallography, medical diagnosis, radiation safety, and XAFS studies. Discrepancies between currently used theoretical approaches of 200% exist for numerous elements from 1 to 3 keV x-ray energies. The key discrepancies are due to the smoothing of edge structure, the use of nonrelativistic wave functions, and the lack of appropriate convergence of wave functions. This paper addresses these key discrepancies and derives new theoretical results of substantially higher accuracy in near-edge soft x-ray regions. The high-energy limitations of the current approach are also illustrated. The energy range covered is 0.1 to 10 keV. The associated figures and tabulation demonstrate the current comparison with alternate theory and with available experimental data. In general, experimental data are not sufficiently accurate to establish the errors and inadequacies of theory at this level. However, the best experimental data and the observed experimental structure as a function of energy are strong indicators of the validity of the current approach. New developments in experimental measurement hold great promise in making critical comparisons with theory in the near future

RADIAL PROFILE OF THE 3.5 keV LINE OUT TO R {sub 200} IN THE PERSEUS CLUSTER

Energy Technology Data Exchange (ETDEWEB)

Franse, Jeroen [Leiden Observatory, Leiden University, Niels Bohrweg 2, Leiden (Netherlands); Bulbul, Esra; Bautz, Mark; McDonald, Michael; Miller, Eric [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Foster, Adam; Randall, Scott W.; Smith, Randall K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Boyarsky, Alexey [Instituut-Lorentz for Theoretical Physics, Leiden University, Niels Bohrweg 2, Leiden (Netherlands); Markevitch, Maxim [NASA Goddard Space Flight Center, 880 Greenbelt Road, MD 20771 (United States); Iakubovskyi, Dmytro; Ruchayskiy, Oleg [Discovery Center, Niels Bohr Institute, Blegdamsvej 17, Copenhagen (Denmark); Loewenstein, Mike [CRESST and X-ray Astrophysics Laboratory NASA/GSFC, Greenbelt, MD 20771 (United States)

2016-10-01

The recent discovery of the unidentified emission line at 3.5 keV in galaxies and clusters has attracted great interest from the community. As the origin of the line remains uncertain, we study the surface brightness distribution of the line in the Perseus cluster since that information can be used to identify its origin. We examine the flux distribution of the 3.5 keV line in the deep Suzaku observations of the Perseus cluster in detail. The 3.5 keV line is observed in three concentric annuli in the central observations, although the observations of the outskirts of the cluster did not reveal such a signal. We establish that these detections and the upper limits from the non-detections are consistent with a dark matter decay origin. However, absence of positive detection in the outskirts is also consistent with some unknown astrophysical origin of the line in the dense gas of the Perseus core, as well as with a dark matter origin with a steeper dependence on mass than the dark matter decay. We also comment on several recently published analyses of the 3.5 keV line.

Study of SiO2 surface sputtering by a 250-550 keV He+ ion beam during high-resolution Rutherford backscattering measurements

International Nuclear Information System (INIS)

Kusanagi, Susumu; Kobayashi, Hajime

2006-01-01

Decreases in oxygen signal intensities in spectra of high-resolution Rutherford backscattering spectrometry (HRBS) were observed during measurements on a 5-nm thick SiO 2 layer on a Si substrate when irradiated by 250-550 keV He + ions. Shifts in an implanted arsenic profile in a 5-nm thick SiO 2 /Si substrate were also observed as a result of He + ion irradiation. These results lead to the conclusion that the SiO 2 surface was sputtered by He + ions in this energy range

Measurement of the Ec.m.=184 keV Resonance Strength in the 26gAl(p,γ)27Si Reaction

International Nuclear Information System (INIS)

Ruiz, C.; Buchmann, L.; Caggiano, J. A.; Davids, B.; Davis, C.; Hutcheon, D.A.; Olin, A.; Ottewell, D.F.; Ruprecht, G.; Trinczek, M.; Vockenhuber, C.; Parikh, A.; Clark, J.A.; Deibel, C.; Lewis, R.; Parker, P.; Wrede, C.; Jose, J.; Chen, A.A.; Ouellet, C.V.

2006-01-01

The strength of the E c.m. =184 keV resonance in the 26g Al(p,γ) 27 Si reaction has been measured in inverse kinematics using the DRAGON recoil separator at TRIUMF's ISAC facility. We measure a value of ωγ=35±7 μeV and a resonance energy of E c.m. =184±1 keV, consistent with p-wave proton capture into the 7652(3) keV state in 27 Si, and discuss the implications of these values for 26g Al nucleosynthesis in typical oxygen-neon white-dwarf novae

Study on neutron capture cross sections using the filtered neutron beams of 55 keV and 144 keV at the Dalat reactor and related applications

International Nuclear Information System (INIS)

Vuong Huu Tan; Nguyen Canh Hai; Pham Ngoc Son; Tran Tuan Anh

2007-01-01

In this fundamental research project on nuclear physics in period of 2006, the neutron capture cross sections for the reactions of 139 La (n,γ) 140 La, 152 Sm (n,γ) 153 Sm, 191 Ir (n,γ) 192 Ir and 193 Ir (n,γ) 194 Ir have been measured at 55 keV and 144 keV by the activation method using the filtered neutron beams of the Dalat nuclear research reactor. The cross sections were determined relative to the standard capture cross sections of 197 Au. The samples and standard were prepaid from high purity (99.99%) foil of Au and natural oxide powders of La 2 O 3 , Sm 2 O 3 and IrO 2 . A high efficient HPGe detector (58%) was used to detect the gamma rays, emitted from the activated samples. The absolute efficiency curve of the detector has been precisely calibrated thanks to a set of standard radioisotope sources and a multi-nuclide standard solution, supported by IAEA. The present results were compared with the previous measurements from EXFOR-2003, and the evaluated values of JENDL 3.3 and ENDF/B-6.8. (author)

Excitation of the helium autoionizing states in He++He collisions, between 3 and 140 keV

International Nuclear Information System (INIS)

Bordenave-Montesquieu, A.; Gleizes, A.; Benoit-Cattin, P.

1982-01-01

The autoionization of the helium atom has been experimentally studied in He + +He collisions between 3 and 140 keV by electron spectrometry. The excitation of the two collision partners has been considered. Above 10 keV, the shapes and excitation cross sections of the 2s 2 1 S, 2s2p 3 P, 2p 2 1 D, and 2s2p 1 P are determined by a numerical fitting procedure which is reported in detail; below 10 keV the ( 1 D+ 1 P), and 2p 2 1 S line intensities are obtained by planimetry since important post-collision effects are observed. From the angular distributions measured below 15 keV, the relative sublevel populations are deduced for the 2p 2 1 D and 2s2p 1 P levels and are compared with those obtained by other authors in a coincidence experiment; the excitation processes are then discussed within the quasimolecular-excitation model. For the highest collision energies, the asymmetry of the angular distributions with respect to 90 0 as well as the line shapes above 100 keV are interpreted by the occurrence of sudden electronic transitions to the continuum. A comparison of the differential cross sections for emission of electrons by autoionization of the fast and slow particles permits us to show that the quasimolecule model cannot explain what is observed above a collision velocity of about 0.5 a.u. The dependence of the total cross sections against the collision energy is also discussed in terms of an evolution of the excitation mechanism from a quasimolecular to an atomic one; the specific variation of the 2s2p 3 P cross section strengthens this interpretation. These total cross sections are compared with those estimated from earlier H + +He data published by us; similar autoionization cross-section values are expected for the two systems at high collision velocity

238U (n,f) measurements below 30 keV

International Nuclear Information System (INIS)

Slovacek, R.E.; Cramer, D.S.; Bean, E.B.; Hockenbury, R.W.; Valentine, J.R.; Block, R.C.

1975-01-01

The 238 U (n,f) cross section has been measured from 3 eV to about 30 keV with the lead slowing down spectrometer at the RPI Linac. Four fission ionization chambers containing a total of about 0.8 gm of 238 U (4.1 ppm 235 U) were used for the measurements. The fission widths of the 6.67, 20.9, and the 36.8 eV resonances were measured as (10 +- 1), (58 +- 9), and (12 +- 2) nanoelectron-volts respectively. The fission cross section integrated over the two subthreshold groups at 720 and 1210 eV and the average fission cross section from 10 to 30 keV are in agreement with a previous time of flight measurement. The fission width at 6.67 eV is 20 times smaller than an upper limit set by the only reported measurement in this energy region; the fission widths obtained in the present investigation are consistent with the (30 +- 50) nanoelectronvolt average width previously obtained for the resonances between 37 and 327 eV in a time of flight measurement using a nuclear device. From the measured fission widths, the 238 U thermal fission cross section was determined to be 2.7 +- 0.3 μ barns. The resonance fission integral was also obtained from the data as 1.33 +- 0.15 mbarns for 238 U. (4 figures, 4 tables) (U.S.)

X-ray extended-range technique for precision measurement of the x-ray mass attenuation coefficient and IM(F) for copper using synchrotron radiation

International Nuclear Information System (INIS)

Tran, C.Q.; Paterson, D.; Barnea, Z.; Cookson, D.J.; Chantler, C.T.

2000-01-01

Full text: Complex X-ray form factors are used in crystallography, material science, medical diagnosis refractive index studies and XAFS. We introduce the X-ray Extended-Range Technique for measurements of the imaginary component of the atomic form factor. We achieve accuracies of 0.27%-0.5% for copper from 8.84 keV to 20 keV. Discrepancies between measurements using earlier experimental techniques are 10%. We achieve reproducibility of 0.02%. New methods of computation are required to approach the accuracy of our data. Results probe the transform of atomic orbital wavefunctions and long-range order. Discrepancies of order 10% between current theory and experiments can be addressed

Multiple capture investigated by coincident electron spectroscopy in X{sup 7+}+Ar, at 70 keV

Energy Technology Data Exchange (ETDEWEB)

Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A. [Universite Paul Sabatier, Toulouse (France). Lab. Collisions-Agregats-Reactivite

1999-11-01

The multiple electron capture in N{sup 7+} + Ar and F{sup 7+}(1s{sup 2}) + Ar systems is investigated at 70 keV with a new electron-recoil ion charge coincidence experiment. The whole electron energy range has been studied. Up to six electrons are found to be captured into autoionizing states. The recoil ion charge distribution associated with the emission of electrons is similar for both systems and found to be in good agreement with the prediction of Niehaus`s model roughly adapted to take into account autoionizing cascades. New findings for the coincident double and triple captures are briefly discussed. A capture of an inner L-shell electron of Ar into the K-shell of the projectile is also observed in N{sup 7+} + Ar collisions. (orig.) 10 refs.

PET attenuation coefficients from CT images: experimental evaluation of the transformation of CT into PET 511-keV attenuation coefficients.

Science.gov (United States)

Burger, C; Goerres, G; Schoenes, S; Buck, A; Lonn, A H R; Von Schulthess, G K

2002-07-01

The CT data acquired in combined PET/CT studies provide a fast and essentially noiseless source for the correction of photon attenuation in PET emission data. To this end, the CT values relating to attenuation of photons in the range of 40-140 keV must be transformed into linear attenuation coefficients at the PET energy of 511 keV. As attenuation depends on photon energy and the absorbing material, an accurate theoretical relation cannot be devised. The transformation implemented in the Discovery LS PET/CT scanner (GE Medical Systems, Milwaukee, Wis.) uses a bilinear function based on the attenuation of water and cortical bone at the CT and PET energies. The purpose of this study was to compare this transformation with experimental CT values and corresponding PET attenuation coefficients. In 14 patients, quantitative PET attenuation maps were calculated from germanium-68 transmission scans, and resolution-matched CT images were generated. A total of 114 volumes of interest were defined and the average PET attenuation coefficients and CT values measured. From the CT values the predicted PET attenuation coefficients were calculated using the bilinear transformation. When the transformation was based on the narrow-beam attenuation coefficient of water at 511 keV (0.096 cm(-1)), the predicted attenuation coefficients were higher in soft tissue than the measured values. This bias was reduced by replacing 0.096 cm(-1) in the transformation by the linear attenuation coefficient of 0.093 cm(-1) obtained from germanium-68 transmission scans. An analysis of the corrected emission activities shows that the resulting transformation is essentially equivalent to the transmission-based attenuation correction for human tissue. For non-human material, however, it may assign inaccurate attenuation coefficients which will also affect the correction in neighbouring tissue.

Efficient scattering of electrons below few keV by Time Domain Structures around injection fronts

Science.gov (United States)

Vasko, I.; Agapitov, O. V.; Mozer, F.; Artemyev, A.; Krasnoselskikh, V.

2016-12-01

Van Allen Probes observations show an abundance of non-linear large-amplitude electrostatic spikes around injection fronts in the outer radiation belt. These spikes referred to as Time Domain Structures (TDS) include electron holes, double layers and more complicated solitary waves. The electron scattering driven by TDS may not be evaluated via the standard quasi-linear theory, since TDS are in principle non-linear plasma modes. In this paper we analyze the scattering of electrons by three-dimensional TDS (with non-negligible perpendicular electric field) around injection fronts. We derive the analytical formulas describing the local scattering by single TDS and show that the most efficiently scattered electrons are those in the first cyclotron resonance (electrons crossing TDS on a time scale comparable with their gyroperiod). The analytical formulas are verified via the test-particle simulation. We compute the bounce-averaged diffusion coefficients and demonstrate their dependence on the TDS spatial distribution, individual TDS parameters and L shell. We show that TDS are able to provide the pitch-angle scattering of <5 keV electrons at rate 10-2-10-4 s-1 and, thus, can be responsible for driving loss of electrons out of injections fronts on a time scale from few minutes to few hours. TDS can be, thus, responsible for driving diffuse aurora precipitations conjugated to injection fronts. We show that the pitch-angle scattering rates driven by TDS are comparable with those due to chorus waves and exceed those due to electron cyclotron harmonics. For injections fronts with no significant wave activity in the frequency range corresponding to chorus waves, TDS can be even dominant mechanism for losses of below few keV electrons.

Energy reflection coefficient for H+ ions at energies between 10 and 80 keV

International Nuclear Information System (INIS)

Chen, C.K.; Bohdansky, J.; Eckstein, W.; Robinson, M.T.

1984-04-01

The energy reflection coefficient for H + ions at energies between 10 keV and 80 keV was determined by experiments and by computer calculations. Measurements were made with graphite, Al, Cu, Mo and W. targets. The angle of ion incidence was restricted to 85 0 , 78 0 and 70 0 measured from the surface normal. Calculated data were obtained by two different Monte Carlo computer programs (MARLOWE, TRIM). It was found that both the calculated and the measured data scale with the parameter epsilon cos 2 α, where epsilon is Lindhard's reduced energy and α the angle of incidence for the ions. The measured values are smaller than those calculated. This can be explained by surface roughness which developed during the ion irradiation

POLARIZED-LIGHT EMISSION IN KEV HE2++NA(3S) COLLISIONS

NARCIS (Netherlands)

BODUCH, P; VANBUCHEM, J; BLIEK, FW; HOEKSTRA, R; MORGENSTERN, R; OLSON, RE

1995-01-01

We investigated l and m-distributions of He II (n = 4) states formed during 2-13.3 keV amu(-1) He2+ + Na(3s) collisions by measuring profiles and the linear polarization of the He II (4 --> 3) emission. We found that at these energies capture into He+(4f) dominates over capture into other He+(4l)

Echo 2: observations at Fort Churchill of a 4-keV peak in low-level electron precipitation

International Nuclear Information System (INIS)

Arnoldy, R.L.; Hendrickson, R.A.; Winckler, J.R.

1975-01-01

The Echo 2 rocket flight launched from Fort Churchill, Manitoba, offered the opportunity to observe high-latitude low-level electron precipitation during quiet magnetic conditions. Although no visual aurora was evident at the time of the flight, an auroral spectrum sharply peaked at a few keV was observed to have intensities from 1 to 2 orders of magnitude lower than peaked spectra typically assoicated with bright auroral forms. There is a growing body of evidence that relates peaked electron spectra to discrete aurora. The Echo 2 observations show that whatever the mechanism for peaking the electron spectrum in and above discrete forms, it operates over a range of precipitation intensities covering nearly 3 orders of magnitude down to subvisual or near subvisual events

SU-F-T-672: A Novel Kernel-Based Dose Engine for KeV Photon Beams

Energy Technology Data Exchange (ETDEWEB)

Reinhart, M; Fast, M F; Nill, S; Oelfke, U [The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London (United Kingdom)

2016-06-15

Purpose: Mimicking state-of-the-art patient radiotherapy with high precision irradiators for small animals allows advanced dose-effect studies and radiobiological investigations. One example is the implementation of pre-clinical IMRT-like irradiations, which requires the development of inverse planning for keV photon beams. As a first step, we present a novel kernel-based dose calculation engine for keV x-rays with explicit consideration of energy and material dependencies. Methods: We follow a superposition-convolution approach adapted to keV x-rays, based on previously published work on micro-beam therapy. In small animal radiotherapy, we assume local energy deposition at the photon interaction point, since the electron ranges in tissue are of the same order of magnitude as the voxel size. This allows us to use photon-only kernel sets generated by MC simulations, which are pre-calculated for six energy windows and ten base materials. We validate our stand-alone dose engine against Geant4 MC simulations for various beam configurations in water, slab phantoms with bone and lung inserts, and on a mouse CT with (0.275mm)3 voxels. Results: We observe good agreement for all cases. For field sizes of 1mm{sup 2} to 1cm{sup 2} in water, the depth dose curves agree within 1% (mean), with the largest deviations in the first voxel (4%) and at depths>5cm (<2.5%). The out-of-field doses at 1cm depth agree within 8% (mean) for all but the smallest field size. In slab geometries, the mean agreement was within 3%, with maximum deviations of 8% at water-bone interfaces. The γ-index (1mm/1%) passing rate for a single-field mouse irradiation is 71%. Conclusion: The presented dose engine yields an accurate representation of keV-photon doses suitable for inverse treatment planning for IMRT. It has the potential to become a significantly faster yet sufficiently accurate alternative to full MC simulations. Further investigations will focus on energy sampling as well as calculation

A 60 keV implanter for metals

International Nuclear Information System (INIS)

Leutenecker, R.; Ryssel, H.; Zeller, K.-H.; Spoehrle, H.P.

1985-01-01

The design and preliminary performance data of a 60 keV high current implanter for the implantation of non-separated ion beams into metals are described. The target chamber accepts samples up to 70 cm in diameter and is equipped with holders to implant ball bearings, axles and other components which have to be rotated during implantation. Samples are mounted on a rugged table which can move up to 35 kg for +-35 cm in the x and y directions. The implanter, including the vacuum system, is completely computer controlled. The ion source is equipped with an oven having a maximum temperature of 1200 0 C and can deliver ion beams of nitrogen as well as different metal ions such as tin and silver with currents up to 10 mA. (Auth.)

A Monte Carlo computer code for evaluating energy loss of 10 keV to 10 MeV ions in amorphous silicon materials

International Nuclear Information System (INIS)

Erramli, H.; Elbounagui, O.; Misdaq, M.A.; Merzouki, A.

2007-01-01

The basic concepts of a computer simulation code for determining the energy loss of ions in the 10 keV to 10 MeV energy range in amorphous silicon materials were presented and discussed. Data obtained were found in good agreement with those obtained by using a SRIM programme. Electronic and nuclear energy losses were evaluated. Variation of the energy loss as a function of the incident ion energy were studied. This new computer code is a good tool for evaluating stopping powers of various materials for light and heavy ions

Fast neutron detection with germanium detectors: computation of response functions for the 692 keV inelastic scattering peak

International Nuclear Information System (INIS)

Fehrenbacher, G.; Meckbach, R.; Paretzke, H.G.

1996-01-01

The dependence of the shape of the right-sided broadening of the inelastic scattering peak at 692 keV in the pulse-height distribution measured with a Ge detector in fast neutron fields on the energy of the incident neutrons has been analyzed. A model incorporating the process contributing to the energy deposition that engender the peak, including the partitioning of the energy deposition by the Ge recoils, was developed. With a Monte Carlo code based on this model, the detector response associated with this peak was computed and compared with results of measurements with quasi-monoenergetic neutrons for energies between 0.88 and 2.1 MeV. A set of 80 response functions for neutron energies in the range from the reaction threshold at 0.7 to 6 MeV was computed, which will serve as a starting point for methods, which aim at obtaining information on the spectral distribution of fast neutron fields for this energy range from measurements with a Ge detector. (orig.)

A superconducting wavelength shifter as primary radiometric source standard in the X-ray range

Energy Technology Data Exchange (ETDEWEB)

Klein, R. [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany)], E-mail: roman.klein@ptb.de; Brandt, G.; Cibik, L.; Gerlach, M.; Krumrey, M.; Mueller, P.; Ulm, G. [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany); Scheer, M. [BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany)

2007-10-11

For more than 20 years, the Physikalisch-Technische Bundesanstalt (PTB) has been using the calculable radiation of bending magnets from the BESSY I and BESSY II electron storage rings in the visible, UV, vacuum-UV (VUV) and X-ray spectral range for radiometry, especially for the calibration of radiation sources and energy-dispersive detectors. Due to its-compared to bending magnets-higher magnetic field, wavelength shifters (WLS) have the potential to extend the usable spectral range for these applications to higher photon energies. Thus, the characteristic energies of BESSY II bending magnet radiation and a 6 T WLS radiation are 2.5 and 11.5 keV, respectively. Within the scope of this work, the properties of the synchrotron radiation from the 6 T WLS have been investigated and compared to theoretical predictions for photon energies up to 150 keV. Good agreement within the experimental uncertainty of several percent was found. Further improvements for a future radiometric use of WLS radiation with low uncertainties will be discussed.

A superconducting wavelength shifter as primary radiometric source standard in the X-ray range

International Nuclear Information System (INIS)

Klein, R.; Brandt, G.; Cibik, L.; Gerlach, M.; Krumrey, M.; Mueller, P.; Ulm, G.; Scheer, M.

2007-01-01

For more than 20 years, the Physikalisch-Technische Bundesanstalt (PTB) has been using the calculable radiation of bending magnets from the BESSY I and BESSY II electron storage rings in the visible, UV, vacuum-UV (VUV) and X-ray spectral range for radiometry, especially for the calibration of radiation sources and energy-dispersive detectors. Due to its-compared to bending magnets-higher magnetic field, wavelength shifters (WLS) have the potential to extend the usable spectral range for these applications to higher photon energies. Thus, the characteristic energies of BESSY II bending magnet radiation and a 6 T WLS radiation are 2.5 and 11.5 keV, respectively. Within the scope of this work, the properties of the synchrotron radiation from the 6 T WLS have been investigated and compared to theoretical predictions for photon energies up to 150 keV. Good agreement within the experimental uncertainty of several percent was found. Further improvements for a future radiometric use of WLS radiation with low uncertainties will be discussed

A superconducting wavelength shifter as primary radiometric source standard in the X-ray range

Science.gov (United States)

Klein, R.; Brandt, G.; Cibik, L.; Gerlach, M.; Krumrey, M.; Müller, P.; Ulm, G.; Scheer, M.

2007-10-01

For more than 20 years, the Physikalisch-Technische Bundesanstalt (PTB) has been using the calculable radiation of bending magnets from the BESSY I and BESSY II electron storage rings in the visible, UV, vacuum-UV (VUV) and X-ray spectral range for radiometry, especially for the calibration of radiation sources and energy-dispersive detectors. Due to its—compared to bending magnets—higher magnetic field, wavelength shifters (WLS) have the potential to extend the usable spectral range for these applications to higher photon energies. Thus, the characteristic energies of BESSY II bending magnet radiation and a 6 T WLS radiation are 2.5 and 11.5 keV, respectively. Within the scope of this work, the properties of the synchrotron radiation from the 6 T WLS have been investigated and compared to theoretical predictions for photon energies up to 150 keV. Good agreement within the experimental uncertainty of several percent was found. Further improvements for a future radiometric use of WLS radiation with low uncertainties will be discussed.

The 871 keV gamma ray from 17O and the identification of plutonium oxide

International Nuclear Information System (INIS)

Peurrung, Anthony; Arthur, Richard; Elovich, Robert; Geelhood, Bruce; Kouzes, Richard; Pratt, Sharon; Scheele, Randy; Sell, Richard

2001-01-01

Disarmament agreements and discussions between the United States and the Russian Federation for reducing the number of stockpiled nuclear weapons require verification of the origin of materials as having come from disassembled weapons. This has resulted in the identification of measurable 'attributes' that characterize such materials. It has been proposed that the 871 keV gamma ray of 17 O can be observed as an indicator of the unexpected presence of plutonium oxide, as opposed to plutonium metal, in such materials. We have shown that the observation of the 871 keV gamma ray is not a specific indicator of the presence of the oxide, but rather indicates the presence of nitrogen

Simbol-X: a formation flight mission with an unprecedented imaging capability in the 0.5-80 keV energy band

Science.gov (United States)

Tagliaferri, Gianpiero; Ferrando, Philippe; Le Duigou, Jean-Michel; Pareschi, Giovanni; Laurent, Philippe; Malaguti, Giuseppe; Clédassou, Rodolphe; Piermaria, Mauro; La Marle, Olivier; Fiore, Fabrizio; Giommi, Paolo

2017-11-01

The discovery of X-ray emission from cosmic sources in the 1960s has opened a new powerful observing window on the Universe. In fact, the exploration of the X-ray sky during the 70s-90s has established X-ray astronomy as a fundamental field of astrophysics. Today, the emission from astrophysical sources is by large best known at energies below 10 keV. The main reason for this situation is purely technical since grazing incidence reflection has so far been limited to the soft X-ray band. Above 10 keV all the observations have been obtained with collimated detectors or coded mask instruments. To make a leap step forward in Xray astronomy above 10 keV it is necessary to extend the principle of focusing X ray optics to higher energies, up to 80 keV and beyond. To this end, ASI and CNES are presently studying the implementation of a X-ray mission called Simbol-X. Taking advantage of emerging technology in mirror manufacturing and spacecraft formation flying, Simbol-X will push grazing incidence imaging up to 80 keV and beyond, providing a strong improvement both in sensitivity and angular resolution compared to all instruments that have operated so far above 10 keV. This technological breakthrough will open a new highenergy window in astrophysics and cosmology. Here we will address the problematic of the development for such a distributed and deformable instrument. We will focus on the main performances of the telescope, like angular resolution, sensitivity and source localization. We will also describe the specificity of the calibration aspects of the payload distributed over two satellites and therefore in a not "frozen" configuration.

Bragg concentrators for hard (> 10 keV) X-ray astronomy: Status report

Energy Technology Data Exchange (ETDEWEB)

Pareschi, G.; Pasqualini, G. [Ferrara, Univ. (Italy). Dipt. di Fisica; Frontera, F. [CNR, Bologna (Italy). Istituto di TESRE]|[Ferrara, Univ. (Italy). Dipt. di Fisica

1997-09-01

The use of focusing telescopes in hard X-ray (E > 10 keV) astronomy will provide better flux sensitivity and imaging performances with respect to the direct-viewing detectors, utilized until now. They present recent results obtained from their group regarding the possible use of Bragg-diffraction technique to design hard X-ray focusing telescopes.

Bragg concentrators for hard (> 10 keV) X-ray astronomy: Status report

International Nuclear Information System (INIS)

Pareschi, G.; Pasqualini, G.; Frontera, F.; Ferrara, Univ.

1997-01-01

The use of focusing telescopes in hard X-ray (E > 10 keV) astronomy will provide better flux sensitivity and imaging performances with respect to the direct-viewing detectors, utilized until now. They present recent results obtained from their group regarding the possible use of Bragg-diffraction technique to design hard X-ray focusing telescopes

Momentum mapping spectrometer for probing the fragmentation dynamics of molecules induced by keV electrons

International Nuclear Information System (INIS)

Singh, Raj; Bhatt, Pragya; Yadav, Namita; Shanker, R

2011-01-01

We describe a new experimental setup for studying the fragmentation dynamics of molecules induced by the impact of keV electrons using the well-known technique of recoil ion momentum spectroscopy. The apparatus consists of mainly a time- and position-sensitive multi-hit particle detector for ion analysis and a channel electron multiplier detector for detecting the ejected electrons. Different components of the setup and the relevant electronics for data acquisition are described in detail with their working principles. In order to verify the reliable performance of the setup, we have recorded the collision-induced ionic spectra of the CO 2 molecule by the impact of keV electrons. Information about the ion pairs of CO + :O + , C + :O + and O + :O + resulting from dissociative ionizing collisions of 20 and 26 keV electrons with a dilute gaseous target of CO 2 molecules has been obtained. Under conditions of the present experiment, the momentum resolutions of the spectrometer for the combined momenta of CO + and O + ions in the direction of the time-of-flight axis and perpendicular to the direction of an electron beam are found to be 10.0 ± 0.2 and 15.0 ± 0.3 au, respectively

Backscattering of 59.54 keV photons for characterization of metallic elements

International Nuclear Information System (INIS)

Elyaseery, I.S.; Chong Chon Sing; Ahmad Shukri Mustapa Kamal; Abdul Aziz Tajuddin

2000-01-01

Scattering measurements of x-rays and gamma rays have been developed for the characterization of internal features of materials such as density or composition. Previous studies were generally carried at small scattering angles. In this paper, a system is described for preliminary studies of back scattering of photons for characterization of materials. The apparatus consist of an annular 100 mCi 241 Am source and a high purity thin intensities for the 59.54 keV photons are presented for different metallic elements such as Al, Cu, Zn, Zr, Nb, Mo, Ag, Cd, In, Sn, Ta and W. The measurements were carried out at back scattering angles of 145 0 , 154 0 , 165 0 . Coherent peak measurements offer greater sensitivity than Compton peak measurements. In particular, the 59.54 keV coherent peak intensity shows a proportional increase with increasing Z number elements except for the elements Ta and W whose absorption edges are in the vicinity of this photon energy. The experimental results demonstrate the feasibility of the backscattering method for the characterization of metallic elements. (Author)

Time-of-flight mass spectrometry with desorption-ionization multiprobes (UV photons and KeV and MeV particles). Cluster atoms are used as projectiles

International Nuclear Information System (INIS)

Brunelle, A.

1990-09-01

A new time-of-flight mass spectrometer, Super-Depil, is used to study secondary ion emission from solid surfaces bombarded by various kinds of primary particles. Three different desorption probes were set up on this machine: a 252 californium source, providing by spontaneous fission about 1 MeV/u energy heavy ions, a 5 to 30 keV energy pulsed caesium ion gun and a pulsed nitrogen laser, which wavelength is 337 mm. A two stages electrostatic mirror was added to the spectrometer. The time spread due to the initial kinetic energy of secondary ions leaving the surface was minimized. The mass resolution is greater than 5000. The analysis of glycosidic terpenes showed the complementarity of the three probes. The study of such metastable ions, with the electrostatic mirror, showed that some fragment ions may conserve the memory of the stereochemistry of the neutral lost. Clusters ions were used as projectiles in the energy range 5-60 keV. A strong non linear enhancement was observed in the secondary ion yield from various targets [fr

150 keV accelerator as pulsed neutron source; Acelerador de 150 keV como fuente de neutrones pulsada

Energy Technology Data Exchange (ETDEWEB)

Cordero, F

1970-07-01

The project of a 150 keV Cockcroft-Walton accelerator built at J.E.N. is described. Beam currents of more than 10 mA, with a neutron intensity of 10{sup 1}1 n.s{sup 1}, are obtained. Also, we report some research made in connection with that project. The role of the contamination in the vacuum system and the performance of the pumps and gauges pumping deuterium gas are studied. Sinusoidal pulses are employed as an analysis method of the discharge in the ion source and the performance of the extracting-focusing system. The parameters of the beam leaving the ion source have been determined; these are used to calculate the electrostatic lenses with the gaussian optics. Measurements concerning deuterium and tritium targets as neutron sources have been made and the processes affecting their practical service life are analyzed. (Author) 71 refs.

Prospects For Gamma-ray Focusing Telescopes Beyond 70/100 Kev

Science.gov (United States)

Frontera, F.

2011-09-01

I will report on the LAUE project, devoted to the development of a lens petal with 20 m focal length. The final goal is to develop a technology for building Laue lenses with a passband from 70/100 to 600 keV. The project is on the way in a synergic collaboration between scientific institutions (University of Ferrara; INAF/IASF, Bologna; CNR/IMEM, Parma; DTM, Modena; Thales-Alenia Space Italy). The LAUE project is supported by the Italian Space Agency ASI.

g-factor of the KeV 5/2- state in 197Pt measured by the TDPAC method

International Nuclear Information System (INIS)

Saxena, R.N.; Soares, J.C.

1981-09-01

The g-factor of the 53 keV state in 197 Pt has been measured using the gamma-gamma time differential perturbed angular correlation (TDPAC) method in an external magnetic field of 25.1 kG. The measurements were performed by utilizing the 346-53 keV gamma cascade in the decay of 95.4 min 197 Pt. The value of the g-factor was obtained to be + 0.335 +- 0.010. This result is compared with the g-factors of similar states in 195 Pt and sup(197,199)Hg. (Author) [pt

Population of the 283 keV level of 137Ba by the β decay of 137Cs

International Nuclear Information System (INIS)

Bikit, I.; Anicin, I.; Slivka, J.; Krmar, M.; Puzovic, J.; Conkic, L.

1996-01-01

The gamma spectrum of 137 Cs was measured by means of a low-level shielded and Compton-suppressed HpGe spectrometer. The gamma line with the energy 283.4 keV and absolute intensity of 5.3(14)x10 -6 was found. It was concluded that the 283.4 keV intermediate level in 137 Ba [seen earlier in (n,n'γ) measurements] is populated in the β decay of 137 Cs with the comparative half-life of logft=15.3(3). copyright 1996 The American Physical Society

Monte-Carlo simulations of secondary electron emission from CsI, induced by 1-10 keV X-rays and electrons

International Nuclear Information System (INIS)

Akkerman, A.; Gibrekhterman, A.; Breskin, A.; Chechik, R.

1992-05-01

A model for electron transport and emission in CsI is proposed. It is based on theoretically calculated microscopic cross-sections for electron interaction with the nuclear and the electronic components of the solid. A Monte Carlo program based on this model was developed to simulate secondary electron emission induced by X-rays and electrons in the energy range of 1 to 10 keV. The calculated secondary emission yields agree with existing experimental data. The model provides all necessary characteristics for the design of radiation detectors based on secondary electron emission. It can be expanded to higher incident energies and other alkali halides. (author)

Surface damage in TEM thick α-Fe samples by implantation with 150 keV Fe ions

International Nuclear Information System (INIS)

Aliaga, M.J.; Caturla, M.J.; Schäublin, R.

2015-01-01

We have performed molecular dynamics simulations of implantation of 150 keV Fe ions in pure bcc Fe. The thickness of the simulation box is of the same order of those used in in situ TEM analysis of irradiated materials. We assess the effect of the implantation angle and the presence of front and back surfaces. The number and type of defects, ion range, cluster distribution and primary damage morphology are studied. Results indicate that, for the very thin samples used in in situ TEM irradiation experiments the presence of surfaces affect dramatically the damage produced. At this particular energy, the ion has sufficient energy to damage both the top and the back surfaces and still leave the sample through the bottom. This provides new insights on the study of radiation damage using TEM in situ

Excitation of the helium autoionizing states in He/sup +/+He collisions, between 3 and 140 keV

Energy Technology Data Exchange (ETDEWEB)

Bordenave-Montesquieu, A.; Gleizes, A.; Benoit-Cattin, P.

1982-01-01

The autoionization of the helium atom has been experimentally studied in He/sup +/+He collisions between 3 and 140 keV by electron spectrometry. The excitation of the two collision partners has been considered. Above 10 keV, the shapes and excitation cross sections of the 2s/sup 2/ /sup 1/S, 2s2p /sup 3/P, 2p/sup 2/ /sup 1/D, and 2s2p /sup 1/P are determined by a numerical fitting procedure which is reported in detail; below 10 keV the (/sup 1/D+/sup 1/P), and 2p/sup 2/ /sup 1/S line intensities are obtained by planimetry since important post-collision effects are observed. From the angular distributions measured below 15 keV, the relative sublevel populations are deduced for the 2p/sup 2/ /sup 1/D and 2s2p/sup 1/ P levels and are compared with those obtained by other authors in a coincidence experiment; the excitation processes are then discussed within the quasimolecular-excitation model. For the highest collision energies, the asymmetry of the angular distributions with respect to 90 /sup 0/ as well as the line shapes above 100 keV are interpreted by the occurrence of sudden electronic transitions to the continuum. A comparison of the differential cross sections for emission of electrons by autoionization of the fast and slow particles permits us to show that the quasimolecule model cannot explain what is observed above a collision velocity of about 0.5 a.u. The dependence of the total cross sections against the collision energy is also discussed in terms of an evolution of the excitation mechanism from a quasimolecular to an atomic one; the specific variation of the 2s2p /sup 3/P cross section strengthens this interpretation. These total cross sections are compared with those estimated from earlier H/sup +/+He data published by us; similar autoionization cross-section values are expected for the two systems at high collision velocity.

Measurement of the −3 keV resonance in the 13C(α,n)16O reaction and its influence on the synthesis of s-process nuclei

International Nuclear Information System (INIS)

La Cognata, M.; Spitaleri, C.; Trippella, O.; Kiss, G. G.; Rogachev, G. V.; Mukhamedzhanov, A. M.; Avila, M.; Guardo, G. L.; Koshchiy, E.; Kuchera, A.; Lamia, L.; Puglia, S. M. R.; Romano, S.; Santiago, D.; Spartà, R.

2012-01-01

The 13 C(α,n) 16 O reaction is the neutron source for the main component of the s-process, responsible of the production of most nuclei in the mass range 90 8 K, corresponding to an energy interval where the 13 C(α,n) 16 O is effective of 140 - 230 keV. In this region, the astrophysical S(E)-factor is dominated by the −3 keV sub-threshold resonance due to the 6.356 MeV level in 17 O, giving rise to a steep increase of the S-factor. Notwithstanding that it plays a crucial role in astrophysics, no direct measurements exist. Therefore, we have applied the Trojan Horse Method (THM) to the 13 C( 6 Li,n 16 O)d quasi-free reaction to achieve an experimental estimate of such contribution. For the first time, the ANC for the 6.356 MeV level has been deduced through the THM as well as the n-partial width, allowing to attain an unprecedented accuracy in the 13 C(α,n) 16 O study. Though a larger ANC for the 6.356 MeV level is measured, our experimental S(E) factor agrees with the most recent extrapolation in the literature in the 140 - 230 keV energy interval, the accuracy being greatly enhanced thanks to this innovative approach.

SMM observation of a cosmic gamma-ray burst from 20 keV to 100 MeV

Science.gov (United States)

Share, G. H.; Matz, S. M.; Messina, D. C.; Nolan, P. L.; Chupp, E. L.

1986-01-01

The Solar Maximum Mission gamma-ray spectrometer has detected an intense gamma-ray burst that occurred on August 5, 1984. The burst originated from a source in the constellation Hydra and lasted about 45 s. Its integral fluence at 20 keV was 0.003 erg/sq cm. Spectral evolution similar to other bursts detected by SMM was observed. The overall shape of the spectrum from 20 keV to 100 MeV, on timescales as short as 2 s, is relatively constant. This shape can be fitted by the sum of an exponential-type function and a power law. There is no evidence for narrow or broadened emission lines.

Near-intrinsic energy resolution for 30–662 keV gamma rays in a high pressure xenon electroluminescent TPC

International Nuclear Information System (INIS)

Álvarez, V.; Borges, F.I.G.M.; Cárcel, S.; Castel, J.; Cebrián, S.; Cervera, A.; Conde, C.A.N.; Dafni, T.; Dias, T.H.V.T.; Díaz, J.

2013-01-01

We present the design, data and results from the NEXT prototype for Double Beta and Dark Matter (NEXT-DBDM) detector, a high-pressure gaseous natural xenon electroluminescent time projection chamber (TPC) that was built at the Lawrence Berkeley National Laboratory. It is a prototype of the planned NEXT-100 136 Xe neutrino-less double beta decay (0νββ) experiment with the main objectives of demonstrating near-intrinsic energy resolution at energies up to 662 keV and of optimizing the NEXT-100 detector design and operating parameters. Energy resolutions of ∼1% FWHM for 662 keV gamma rays were obtained at 10 and 15 atm and ∼5% FWHM for 30 keV fluorescence xenon X-rays. These results demonstrate that 0.5% FWHM resolutions for the 2459 keV hypothetical neutrino-less double beta decay peak are realizable. This energy resolution is a factor 7–20 better than that of the current leading 0νββ experiments using liquid xenon and thus represents a significant advancement. We present also first results from a track imaging system consisting of 64 silicon photo-multipliers recently installed in NEXT–DBDM that, along with the excellent energy resolution, demonstrates the key functionalities required for the NEXT-100 0νββ search

Structural analysis and evaluation of actual PC bridge using 950 keV/3.95 MeV X-band linacs

Science.gov (United States)

Takeuchi, H.; Yano, R.; Ozawa, I.; Mitsuya, Y.; Dobashi, K.; Uesaka, M.; Kusano, J.; Oshima, Y.; Ishida, M.

2017-07-01

In Japan, bridges constructed during the strong economic growth era are facing an aging problem and advanced maintenance methods have become strongly required recently. To meet this demand, we develop the on-site inspection system using 950 keV/3.95 MeV X-band (9.3 GHz) linac X-ray sources. These systems can visualize in seconds the inner states of bridges, including cracks of concrete, location and state of tendons (wires) and other imperfections. At the on-site inspections, 950 keV linac exhibited sufficient performance. But, for thicker concrete, it is difficult to visualize the internal state by 950 keV linac. Therefore, we proceeded the installation of 3.95 MeV linac for on-site bridge inspection. In addition, for accurate evaluation, verification on the parallel motion CT technique and FEM analysis are in progress.

8 to 11 keV x-ray sources for imaging and absorption experiments

International Nuclear Information System (INIS)

Molitoris, J.D.; Phillion, D.W.; Osterheld, A.L.; Stewart, R.E.; Rothman, S.D.

1992-01-01

We have measured the 8 to 11 keV emission spectra from plasmas produced by impinging 0.53 μm 100 and 200 ps FWHM Gaussian laser pulses on targets of different materials. The experimental spectra from W and Zn are identified by comparison with local thermodynamic equilibrium plasma emission calculations

Absolute cross section measurement for the ionization of the K-shell of titanium and nickel by electron impact (50 KEV)

International Nuclear Information System (INIS)

Jessenberger, J.

1974-01-01

The yield of characteristic X-ray K radiation of titanium during bombardment with electrons in the energy region of 6-50 keV and of nickel at 9-50 keV was measured, and the cross sections for th ionization of the K shell of titanium and nickel were determined from this. The results obtained are compared with several theoretical models. (WL/LN) [de

2 keV filters of quasi-mono-energetic neutrons

International Nuclear Information System (INIS)

Adib, M.; Habib, N.; El-Mesiry, M.S.; Bashter, I.I.; Saleh, A.; Fathallah, M.

2013-01-01

A simulation study for the production of 2 keV filters of quasi-mono-energetic neutrons based on the deep interference minima in the 45 Sc total cross-section was carried out. A computer code QMENF-II was adapted to calculate the optimum amounts of the 45 Sc as a main filter element and additional component ones to obtain sufficient intensity at high resolution and purity of the filtered quasi-mono-energetic neutrons. The emitted neutron spectrum from nuclear reactor and from the reaction of 2.6 MeV protons on a lithium fluoride target at the accelerator beam port, are used for simulation

Cross sections for ionization of tetrahydrofuran by protons at energies between 300 and 3000 keV

Science.gov (United States)

Wang, Mingjie; Rudek, Benedikt; Bennett, Daniel; de Vera, Pablo; Bug, Marion; Buhr, Ticia; Baek, Woon Yong; Hilgers, Gerhard; Rabus, Hans

2016-05-01

Double-differential cross sections for ionization of tetrahydrofuran by protons with energies from 300 to 3000 keV were measured at the Physikalisch-Technische Bundesanstalt ion accelerator facility. The electrons emitted at angles between 15∘ and 150∘ relative to the ion-beam direction were detected with an electrostatic hemispherical electron spectrometer. Single-differential and total ionization cross sections have been derived by integration. The experimental results are compared to the semiempirical Hansen-Kocbach-Stolterfoht model as well as to the recently reported method based on the dielectric formalism. The comparison to the latter showed good agreement with experimental data in a broad range of emission angles and energies of secondary electrons. The scaling property of ionization cross sections for tetrahydrofuran was also investigated. Compared to molecules of different size, the ionization cross sections of tetrahydrofuran were found to scale with the number of valence electrons at large impact parameters.

Measurement of the fission cross section of uranium-235 between 4 eV and 20 keV; Mesure de la section efficace de fission de l'uranium-235 entre 4 eV et 20 keV

Energy Technology Data Exchange (ETDEWEB)

Michaudon, A; Genin, R; Joly, R; Vendryes, G

1959-01-01

The neutron fission cross section of uranium-235 has been measured between 4 ev and 20 kev by the time of flight method with the Saclay electron linear accelerator as a pulsed neutron source. After a brief description of the experimental apparatus and the conditions of work during the experiment, the curve {sigma}{sub F} {radical}E in the energy range studied is shown. This curve is then analyzed by the ''area'' method and a set of {sigma}{sub 0} {gamma}{sub F} values is obtained. With {sigma}{sub 0} {gamma} values measured in other laboratories, it is possible to compute fission widths for several resonances and to study their distribution. This distribution is then compared to Porter-Thomas distributions with different values of the number of exit channels. (authors) [French] La section efficace de fission de l'uranium--235 a ete mesuree entre 4 eV et 20 KeV par la methode du temps de vol en utilisant l'accelerateur lineaire a electrons de Saclay comme source pulses de neutrons. Apres une rapide description de l'appareillage experimental et des conditions de fonctionnement au cours de l'experience, on presente la courbe {sigma}{sub F} {radical}E obtenue dans la game d'energie etudiee. Cette courbe est ensuite analysee par la methode de surface des resonances et un lot de valeurs de {sigma}{sub 0} {gamma}{sub F} est obtenue. Conjuguee avec les valeurs de {sigma}{sub 0} {gamma} obtenues dans d'autres laboratoires, cette analyse permet de calculer les largeurs de fission pour plusieurs resonances et d'etudier leur distribution. Cette distribution est ensuite comparee aux distributions de Porter et Thomas correspondant a differentes valeurs du nombre de voies de sortie. (auteurs)

Study of SiO{sub 2} surface sputtering by a 250-550 keV He{sup +} ion beam during high-resolution Rutherford backscattering measurements

Energy Technology Data Exchange (ETDEWEB)

Kusanagi, Susumu [Materials Analysis Laboratory, Advanced Design Technology Center, Sony Corporation, 4-16-1 Okata Atsugi-shi, Kanagawa 243-0021 (Japan)]. E-mail: susumu.kusanagi@jp.sony.com; Kobayashi, Hajime [Materials Analysis Laboratory, Advanced Design Technology Center, Sony Corporation, 4-16-1 Okata Atsugi-shi, Kanagawa 243-0021 (Japan)

2006-08-15

Decreases in oxygen signal intensities in spectra of high-resolution Rutherford backscattering spectrometry (HRBS) were observed during measurements on a 5-nm thick SiO{sub 2} layer on a Si substrate when irradiated by 250-550 keV He{sup +} ions. Shifts in an implanted arsenic profile in a 5-nm thick SiO{sub 2}/Si substrate were also observed as a result of He{sup +} ion irradiation. These results lead to the conclusion that the SiO{sub 2} surface was sputtered by He{sup +} ions in this energy range.

Galaxy Clusters in the Swift/BAT era II: 10 more Clusters detected above 15 keV

Energy Technology Data Exchange (ETDEWEB)

Ajello, M.; /SLAC /KIPAC, Menlo Park; Rebusco, P.; /KIPAC, Menlo Park; Cappelluti, N.; /Garching, Max Planck Inst., MPE /Maryland U., Baltimore County; Reimer, O.; /SLAC /Palermo Observ.; Boehringer, H.; /Garching, Max Planck Inst., MPE; La Parola, V.; Cusumano, G.; /Palermo Observ.

2010-10-27

We report on the discovery of 10 additional galaxy clusters detected in the ongoing Swift/BAT all-sky survey. Among the newly BAT-discovered clusters there are: Bullet, Abell 85, Norma, and PKS 0745-19. Norma is the only cluster, among those presented here, which is resolved by BAT. For all the clusters we perform a detailed spectral analysis using XMM-Newton and Swift/BAT data to investigate the presence of a hard (non-thermal) X-ray excess. We find that in most cases the clusters emission in the 0.3-200 keV band can be explained by a multi-temperature thermal model confirming our previous results. For two clusters (Bullet and Abell 3667) we find evidence for the presence of a hard X-ray excess. In the case of the Bullet cluster, our analysis confirms the presence of a non-thermal, power-law like, component with a 20-100 keV flux of 3.4 x 10{sup -12} erg cm{sup -2} s{sup -1} as detected in previous studies. For Abell 3667 the excess emission can be successfully modeled as a hot component (kT = {approx}13 keV). We thus conclude that the hard X-ray emission from galaxy clusters (except the Bullet) has most likely thermal origin.

GALAXY CLUSTERS IN THE SWIFT/BAT ERA. II. 10 MORE CLUSTERS DETECTED ABOVE 15 keV

International Nuclear Information System (INIS)

Ajello, M.; Reimer, O.; Rebusco, P.; Cappelluti, N.; Boehringer, H.; La Parola, V.; Cusumano, G.

2010-01-01

We report on the discovery of 10 additional galaxy clusters detected in the ongoing Swift/Burst Alert Telescope (BAT) all-sky survey. Among the newly BAT-discovered clusters there are Bullet, A85, Norma, and PKS 0745-19. Norma is the only cluster, among those presented here, which is resolved by BAT. For all the clusters, we perform a detailed spectral analysis using XMM-Newton and Swift/BAT data to investigate the presence of a hard (non-thermal) X-ray excess. We find that in most cases the clusters' emission in the 0.3-200 keV band can be explained by a multi-temperature thermal model confirming our previous results. For two clusters (Bullet and A3667), we find evidence for the presence of a hard X-ray excess. In the case of the Bullet cluster, our analysis confirms the presence of a non-thermal, power-law-like, component with a 20-100 keV flux of 3.4 x 10 -12 erg cm -2 s -1 as detected in previous studies. For A3667, the excess emission can be successfully modeled as a hot component (kT ∼ 13 keV). We thus conclude that the hard X-ray emission from galaxy clusters (except the Bullet) has most likely a thermal origin.

Quiet-time Suprathermal (~0.1-1.5 keV) Electrons in the Solar Wind

Science.gov (United States)

Tao, Jiawei; Wang, Linghua; Zong, Qiugang; Li, Gang; Salem, Chadi S.; Wimmer-Schweingruber, Robert F.; He, Jiansen; Tu, Chuanyi; Bale, Stuart D.

2016-03-01

We present a statistical survey of the energy spectrum of solar wind suprathermal (˜0.1-1.5 keV) electrons measured by the WIND 3DP instrument at 1 AU during quiet times at the minimum and maximum of solar cycles 23 and 24. After separating (beaming) strahl electrons from (isotropic) halo electrons according to their different behaviors in the angular distribution, we fit the observed energy spectrum of both strahl and halo electrons at ˜0.1-1.5 keV to a Kappa distribution function with an index κ and effective temperature Teff. We also calculate the number density n and average energy Eavg of strahl and halo electrons by integrating the electron measurements between ˜0.1 and 1.5 keV. We find a strong positive correlation between κ and Teff for both strahl and halo electrons, and a strong positive correlation between the strahl n and halo n, likely reflecting the nature of the generation of these suprathermal electrons. In both solar cycles, κ is larger at solar minimum than at solar maximum for both strahl and halo electrons. The halo κ is generally smaller than the strahl κ (except during the solar minimum of cycle 23). The strahl n is larger at solar maximum, but the halo n shows no difference between solar minimum and maximum. Both the strahl n and halo n have no clear association with the solar wind core population, but the density ratio between the strahl and halo roughly anti-correlates (correlates) with the solar wind density (velocity).

Measurement of the 238U subthreshold fission cross section for incident neutron energies between 0.6 and 100 keV

International Nuclear Information System (INIS)

Difilippo, F.C.; Perez, R.B.; de Saussure, G.; Olsen, D.K.; Ingle, R.W.

1977-01-01

The neutron-induced 238 U subthreshold fission cross section has been measured in the neutron energy range between 0.6 and 100 keV. A total of 28 fission clusters were identified. The well-known clusters at 721 and 1210 eV appeared resolved into their Class I components. Average 238 U subthreshold fission cross sections were determined and compared with available results in the literature. The measurement is interpreted in terms of fission doorway (Class II levels) arising from the assumption of the existence of a double-humped fission barrier for the ( 238 U + n) compound nucleus at large deformations. On the basis of this model, several fission barrier parameters were determined

Electron capture by He2+ ions in collisions with H and H2 at impact energies below 10 keV

International Nuclear Information System (INIS)

Nutt, W.L.; McCullough, R.W.; Brady, K.; Shah, M.B.; Gilbody, H.B.

1978-01-01

Total cross sections for the process He 2+ + H(1s) → He + (Σn, 1) + H + involving capture into all final bound states of He + have been determined for 3 He 2+ ions in the range 1.5-9.0 keV using a furnace-target technique previously employed for similar measurements at higher impact energies. Measured cross sections are considerably smaller than those measured previously by Fite et al (Proc. R.Soc.; A268:527 (1962)) and are in better accord with recent theoretical estimates. A likely explanation for the discrepancy is given in terms of the corresponding cross sections for electron capture in He 2+ -H 2 collisions which have also been determined. (author)

Calibration of thin-film dosimeters irradiated with 80-120 kev electrons

DEFF Research Database (Denmark)

Helt-Hansen, J.; Miller, A.; McEwen, M.

2004-01-01

A method for calibration of thin-film dosimeters irradiated with 80-120keV electrons has been developed. The method is based on measurement of dose with a totally absorbing graphite calorimeter, and conversion of dose in the graphite calorimeter to dose in the film dosimeter by Monte Carlo calcul......V electron irradiation. The two calibrations were found to be equal within the estimated uncertainties of +/-10% at 1 s.d. (C) 2004 Elsevier Ltd. All rights reserved....

One-sided imaging of large, dense objects using the 511 keV photons from induced pair production

Energy Technology Data Exchange (ETDEWEB)

Tavora, L.M.; Gilboy, W.B.; Morton, E.J. [Univ. of Surrey, Guildford (United Kingdom). Physics Dept.; Morgado, R.E.; Estep, R.J.; Rawool-Sullivan, M. [Los Alamos National Lab., NM (United States)

1998-03-01

The use of annihilation photons from photon-induced electron-positron pair production as a means of inspecting objects when only one side is accessible is described. The Z2 dependence of the pair production cross section and the high penetration of 511 keV photons suggest that this method should be capable of localizing high Z materials in lower Z matrices. The experimental results for the dependence of the back streaming photon yield on Z indicate that dynamic ranges of the order of 20 may be obtained for materials with 4 < Z < 82. Results for point to point images obtained in line scans of representative geometries are also shown. Simulation studies based on the EGS4 Monte Carlo code were also performed and their results show an agreement with experimental data of the order of 5%.

One-sided imaging of large, dense objects using the 511 keV photons from induced pair production

International Nuclear Information System (INIS)

Tavora, L.M.; Gilboy, W.B.; Morton, E.J.

1998-03-01

The use of annihilation photons from photon-induced electron-positron pair production as a means of inspecting objects when only one side is accessible is described. The Z2 dependence of the pair production cross section and the high penetration of 511 keV photons suggest that this method should be capable of localizing high Z materials in lower Z matrices. The experimental results for the dependence of the back streaming photon yield on Z indicate that dynamic ranges of the order of 20 may be obtained for materials with 4 < Z < 82. Results for point to point images obtained in line scans of representative geometries are also shown. Simulation studies based on the EGS4 Monte Carlo code were also performed and their results show an agreement with experimental data of the order of 5%

Comparison of secondary ion emission induced in silicon oxide by MeV and KeV ion bombardment

International Nuclear Information System (INIS)

Allali, H.; Nsouli, B.; Thomas, J.P.; Szymczak, W.; Wittmaack, K.

1993-09-01

The surface and near-surface composition of SiO 2 layers, has been investigated by negative secondary ion emission mass spectrometry (SIMS) using MeV and KeV ion bombardment in combination with time-of-flight (TOF) mass analysis. The spectra recorded in the mass range 0-100 u are dominated by surface impurities, notably hydrocarbons and silicon polyanions incorporating H and OH entities. The characteristic (fragmentation) patterns are quite different for light and high-velocity ion impact. In high-velocity TOF-SIMS analysis of P-doped layers, prepared by chemical vapour deposition (CVD), the mass lines at 63 and 79 u are very prominent and appear to correlate with the phosphorus concentration (PO 2 and PO 3 , respectively). It is shown, however, that for unambiguous P analysis one has to use dynamic SIMS or high mass resolution. (author) 11 refs., 5 figs

Differential elastic and inelastic cross sections in 1. 5 <= E/sub 0/ <= 25 keV He/sup +/-H collisions at scattering angles thetasub(lab) ranging from 5' to 2/sup 0/

Energy Technology Data Exchange (ETDEWEB)

Bordenave-Montesquieu, D.; Nouet, P.; Boutonnet, A.; Bergnes, C.; Dagnac, R.

1987-09-14

Elastic and inelastic cross sections, differential in energy loss and scattering angle, have been determined from the energy loss spectra of 1.5 - 25 keV He/sup +/ scattered from atomic hydrogen at scattering angles from 5'-2/sup 0/ (laboratory frame). The experimental results compare favourably with the experimental and theoretical data obtained at low incident energies by other authors, but for the higher energies, the present results exhibit a strong disagreement with many of the reported calculations.

Cross section measurements of the 10B(d,n0)11C reaction below 160 keV

International Nuclear Information System (INIS)

Stave, S.; Ahmed, M. W.; Blackston, M. A.; Crowell, A. S.; Henshaw, S. S.; Howell, C. R.; Kingsberry, P.; Perdue, B. A.; Weller, H. R.; Antolak, A. J.; Doyle, B. L.; Rossi, P.; Prior, R. M.; Spraker, M. C.

2008-01-01

New data were taken at the Triangle Universities Nuclear Laboratory to investigate the plausibility of using low energy deuterons and the 10 B(d,n) 11 C reaction as a portable source of 6.3 MeV neutrons. Analysis of the data at and below incident deuteron energies of 160 keV indicates an n 0 neutron cross section that is lower than previous estimates by at least three orders of magnitude. In separate runs, deuterons with two different energies (160 and 140 keV) were stopped in a 10 B target. The resulting n 0 neutrons of approximately 6.3 MeV were detected at angles between 0 deg. and 150 deg. The angle integrated yields were used to determine the astrophysical S factor for this reaction assuming a constant value for the S factor below 160 keV. The cross sections reported between 130 and 160 keV were calculated using the extracted value of the S factor. The measured n 0 cross section is several orders of magnitude smaller than previous results, thus eliminating 10 B(d,n) 11 C as a portable source of intense neutrons with low energy deuteron beams on the order of tens of microamps. In order to gain insight into the reaction dynamics at these low energies the cross section results have been compared with results from calculations using the distorted wave Born approximation (DWBA) and a detailed Hauser-Feshbach calculation performed by the authors. The angular distribution is consistent with the Hauser-Feshbach calculation suggesting a statistical compound nucleus reaction rather than a direct reaction

The X-ray structure of Centaurus A from 0.1 to 50 keV observations with Exosat

International Nuclear Information System (INIS)

Morini, M.; Anselmo, F.; Molteni, D.

1989-01-01

The results from four Exosat observations of the radio galaxy Centaurus A performed during 1984-1985 are presented. The emission from the nucleus detected in the medium-energy X-ray band exhibits time variability on all time scales from a few minutes to years. Small changes are detected in the spectra of the source obtained at the different epochs. All spectra are well fitted by a power law with energy index alpha = 0.70 and strong low-energy photoelectric absorption, with an absorbing column N(H) variable between 1.4 and 1.7 x 10 to the 23rd/sq cm. An unabsorbed component is observed at low energies in all spectra which can be fitted with a thermal spectrum with T roughly 1.6 keV and which is consistent with the integrated emission of the spatially extended sources outside the nucleus. An iron fluorescence line is detected at 6.4 keV which seems to be constant in absolute intensity. The iron K-absorption edge at 7.1 keV is also observed, and the abundance of absorbing iron relative to lighter elements is larger than the cosmic value. 43 refs

Status report on a dc 130-mA, 75-keV proton injector

International Nuclear Information System (INIS)

Sherman, J.; Arvin, A.; Hodgkins, D.

1997-01-01

A 110-mA, 75-keV dc proton injector is being developed at Los Alamos. We use a microwave proton source coupled to a two solenoid, space-charge neutralized, low-energy beam transport (LEBT) system. The ion source produces 110-mA proton current at 75 keV using 600 - 800 W of 2.45 GHz input discharge power. Typical proton fraction is 85-90% of the total extracted ion current, and the rms normalized beam emittance after transport through a prototype 2.1 m LEBT is 0.20 (πmm-mrad). Beam space-charge neutralization is measured to be > 98% which enables the solenoid magnetic transport to successfully match the injector beam into a radio-frequency quadrupole (RFQ). Beam simulations indicate small emittance growth in the proposed 2.8 m low-energy demonstration accelerator (LEDA) LEBT. The LEBT also contains beam diagnostics, steering, and a beam deflector for variable duty factor and accelerator fast protect functions. The injector computer controls and reliability status are also discussed

SMM observations of gamma-ray transients. 2: A search for gamma-ray lines between 400 and 600 keV from the Crab Nebula

Science.gov (United States)

Harris, Michael J.; Share, Gerald H.; Leising, Mark D.

1994-01-01

We have search spectra obtained by the Solar Maximum Mission Gamma-Ray Spectrometer during 1981-1988 for evidence of transient gamma-ray lines from the Crab Nebula which have been reported by previous experiments at energies 400-460 keV and 539 keV. We find no evidence for significant emission in any of these lines on time scales between aproximately 1 day and approximately 1 yr. Our 3 sigma upper limits on the transient flux during 1 d intervals are approximately equal to 2.2 x 10(exp -3) photons/sq cm/s for narrow lines at any energy, and approximately equal to 2.9 x 10(exp -3) photons/sq cm/s for the 539 keV line if it is as broad as 42 keV Full Width at Half Maximum (FWHM). We also searched our data during the approximately 5 hr period on 1981 June 6 during which Owens, Myers, & Thompson (1985) reported a strong line at 405 keV. We detected no line down to a 3 upper sigma limit of 3.3 x 10(exp -3) photons/sq cm/s in disagreement with the flux 7.2 +/- 2.1 x 10(exp -3) photos/sq cm/s measured by Owens et al.

Measurement of mass attenuation coefficients of Rhizophora spp. binderless particleboards in the 16.59-25.26 keV photon energy range and their density profile using x-ray computed tomography

Energy Technology Data Exchange (ETDEWEB)

Marashdeh, M.W., E-mail: mwmarashdeh@yahoo.com [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Bauk, S. [Physics Section, P.P.P. Jarak Jauh, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Tajuddin, A.A. [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Hashim, R. [Division of Bio-resource, Paper and Coatings Technology, School of Industrial Technology, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

2012-04-15

The mass attenuation coefficients of Rhizophora spp. binderless particleboard with four different particle sizes (samples A, B, C and D) and natural raw Rhizophora spp. wood (sample E) were determined using single-beam photon transmission in the energy range between 16.59 and 25.26 keV. This was done by determining the attenuation of K{sub {alpha}1} X-ray fluorescent (XRF) photons from niobium, molybdenum, palladium, silver and tin targets. The results were compared with theoretical values of young-age breast (Breast 1) and water calculated using a XCOM computer program. It was found that the mass attenuation coefficient of Rhizophora spp. binderless particleboards to be close to the calculated XCOM values in water than natural Rhizophora spp. wood. Computed tomography (CT) scans were then used to determine the density profile of the samples. The CT scan results showed that the Rhizophora spp. binderless particleboard has uniform density compared to natural Rhizophora spp. wood. In general, the differences in the variability of the profile density decrease as the particle size of the pellet samples decreases. - Highlights: Black-Right-Pointing-Pointer Mass attenuation coefficients were determined by X-ray fluorescent photons. Black-Right-Pointing-Pointer Sample with smaller particle size found very close to calculated water XCOM. Black-Right-Pointing-Pointer X-ray computed tomography scanner was used to investigate the density distribution. Black-Right-Pointing-Pointer The density distribution profile is improved with the decrease in the particle size. Black-Right-Pointing-Pointer Rhizophora spp. binderless particleboard could be used as phantom material.

Solar Cycle dependence of 5-55 keV Cassini/INCA energetic neutral atom (ENA) images of the Heliosheath and in situ Voyager/LECP ion measurements

Science.gov (United States)

Krimigis, S. M.; Dialynas, K.; Mitchell, D. G.; Decker, R. B.; Roelof, E. C.

2015-12-01

The heliosheath has been identified as the most probable source of ENAs that INCA detects but its variability due to solar activity throughout the solar cycle (SC) has not been resolved to date. We show all-sky, 5-55 keV ENA H maps from the year 2003 to 2014 and compare the solar cycle variation of the ENAs in both the heliospheric nose (upstream) and anti-nose (downstream) directions with the > 30 keV ions measured within the heliosheath by the Low Energy Charged Particle (LECP) detector on Voyagers 1, 2 (V1, V2) where we measure protons in overlapping energy bands ~30-55 keV. We find that a) Toward the anti-nose direction the ENA-H intensities decline during SC23, i.e. after 2003 ENA intensities decreased by ~ x2 at all energies by the end of year 2011, ~1 year after the observed minimum in solar activity; b) This ENA decrease (5.2-55 keV) during 2009-2011 is consistent with the concurrent intensity decrease of the > 30 keV ions (by a factor of 2-3) observed in situ by V1 and V2 in the heliosheath; c) Toward the nose direction, minimum intensities in both INCA ENAs and the V2 ions at E > 28 keV occur during the year 2013, with a subsequent recovery from 2014 to date (by a factor of ~2 in the > 35 keV ENA data). These quantitative correlations between the decreases of INCA ENAs (in both the heliospheric nose and anti-nose directions) and the in situ V1 and V2 ion measurements (separated by > 130 AU) during the declining phase of SC23, along with their concurrent jointly shared recoveries at the onset of SC24, imply that: 1) the 5-55 keV ENAs are produced in the heliosheath (because their transit times over 100 AU are less than a few months at energies > 40 keV), thus proving that our ENA observations can provide the ground truth for constructing comprehensive global heliosphere models; 2) the global heliosheath responds promptly (within ~1-1.5 yrs) to outward-propagating solar wind changes throughout the solar cycle.

Study of vacancy decays in the L-shell photoionization of barium in the excitation energy range of 5.6-30 keV: from L{sub 2} edge to energy high above the thresholds of double L-vacancy production

Energy Technology Data Exchange (ETDEWEB)

Zou, Y [Key Laboratory of Applied Ion Beam Physics (Chinese Educational Ministry), Fudan University, Shanghai 200433 (China); Oura, M [RIKEN Spring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Hutton, R [Lund Observatory, SE-221 00 Lund (Sweden); Yamaoka, H [RIKEN Spring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Takeshima, N [Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan); Takahiro, K [Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan); Kawatsura, K [Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan); Mukoyama, T [Kansai Gaidai University, 16-1 Nakamiyahigashino-cho, Hirakata, Osaka 573-1001 (Japan)

2006-11-28

Photoinduced Ba L x-rays were measured, in the excitation energy range of 5.6-30 keV, by using high-brilliance undulator radiation. The obtained intensity ratios, the excitation-energy independent L{beta}{sub 4}/L{beta}{sub 3}, L{eta}/L{beta}{sub 1}, L{iota}/L{alpha}{sub 1,2}, L{beta}{sub 6}/L{alpha}{sub 1,2} and L{beta}{sub 2,15}/L{alpha}{sub 1,2} as well as the excitation-energy dependent L{beta}{sub 1}/L{alpha}{sub 1,2}, L{beta}{sub 3}/L{alpha}{sub 1,2} and L{beta}{sub 3}/L{beta}{sub 1}, were compared with theoretical calculations, in which the calculations were performed by applying various subsets of the L subshell fluorescence yields and Coster-Kronig yields. Deviations of the theoretical calculations from the experimental results call on improvements in theory for the emission rates. We have also surveyed the L{alpha}{sub 1,2} related x-ray hypersatellite lines in the photoinduced Ba L x-ray spectrum.

Surface damage studies of ETFE polymer bombarded with low energy Si ions (≤100 keV)

International Nuclear Information System (INIS)

Minamisawa, Renato Amaral; Almeida, Adelaide De; Budak, Satilmis; Abidzina, Volha; Ila, Daryush

2007-01-01

Surface studies of ethylenetetrafluoroethylene (ETFE), bombarded with Si in a high-energy tandem Pelletron accelerator, have recently been reported. Si ion bombardment with a few MeV to a few hundred keV energies was shown to be sufficient to produce damage on ETFE film. We report here the use of a low energy implanter with Si ion energies lower than 100 keV, to induce changes on ETFE films. In order to determine the radiation damage, ETFE bombarded films were simulated with SRIM software and analyzed with optical absorption photometry (OAP), Raman and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy to show quantitatively the physical and chemical property changes. Carbonization occurs following higher dose implantation, and hydroperoxides were formed following dehydroflorination of the polymer

TLD personnel monitoring dose estimation- extending the upper limit of the dose range

International Nuclear Information System (INIS)

Popli, K.L.; Sathian, Deepa; Divakaran, T.; Massand, O.P.

2001-01-01

TLD personnel monitoring was introduced in the year 1975 in India and at present nearly 41,000 radiation workers are being monitored by 13 monitoring laboratories all over India. The BARC- TLD being used for personnel monitoring is based on CaSO 4 :Dy embedded in PTFE and semi-automatic TL reader using hot N 2 Gas for heating the dosimeters. This reader has the range to measure γ dose from ten μSv to 3 μSv and x-ray dose form 1 μ Sv to 0.3 Sv due to the higher sensitivity of CaSO 4 : Dy to lower energy photons (20keV-50 keV) generated by diagnostic x-ray units. The x-ray radiation workers are at present nearly 35% of the total radiation workers monitored and this number is expected to grow as more and more number of x-ray workers are covered under this service. The upper limit of the x-ray dose range of the instrument is 0.3 Sv, whereas in the past one year it has been observed that at least 25% of the total overexposures reported in case of x-ray workers have recorded the dose more than 0.3 Sv. This paper presents the technique developed to extend the upper limit of the range from 0.3 Sv to 1 Sv for x-rays and 10 Sv for γ rays

Calibration of dosimeters at 80-120 keV electron irradiation

DEFF Research Database (Denmark)

Miller, A.; Helt-Hansen, J.

to calibrate thin-film dosimeters (Risø B3 and alanine films) by irradiation at the 80–120 keV electron accelerators. This calibration was compared to a 10MeV calibration, and we show that the radiation response of the dosimeter materials (the radiation chemical yield) is constant at these irradiation energies....... However, dose gradients within the dosimeters, when it is irradiated at low electron energies,mean that calibration function here will depend on both irradiation energy and the required effective point of measurement of the dosimeter. These are general effects that apply to any dosimeter that has a non...

Investigation of multilayer X-ray optics for 6 keV to 20 keV energy range

Czech Academy of Sciences Publication Activity Database

Oberta, Peter; Platonov, Y.; Flechsig, U.

2012-01-01

Roč. 19, č. 5 (2012), s. 675-681 ISSN 0909-0495 Institutional research plan: CEZ:AV0Z10100522 Keywords : X-ray optics * multilayer * energy resolution Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.186, year: 2012 http://journals.iucr.org/s/issues/2012/05/00/issconts.html

Effects of keV electron irradiation on the avalanche-electron generation rates of three donors on oxidized silicon

International Nuclear Information System (INIS)

Sah, C.; Sun, J.Y.; Tzou, J.J.

1983-01-01

After keV electron beam irradiation of oxidized silicon, the avalanche-electron-injection generation rates and densities of the bulk compensating donor, the interface states, and the turnaround trap all increase. Heating at 200 0 C can anneal out these three donor-like traps, however, it cannot restore the generation rates back to their original and lower pre-keV electron irradiation values. The experimental results also indicate that all three traps may be related to the same mobile impurity species whose bonds are loosened by the keV electrons and then broken or released by the avalanche injected electrons

Energy distribution measurements of 300 keV transmitted protons at the axial-to-planar channeling transition in silicon

International Nuclear Information System (INIS)

Bulgakov, Yu.V.; Lenkeit, K.; Stolle, R.

1983-01-01

The energy distribution of protons with initial energy of 300 keV which passed through a 0.76 μm thick Si monocrystal film was measured under the conditions of transition from the axial to planar (110) channeling. The experimental angular dependences of the transparency coefficient and of the first three moments of the energy distributions (energy loss, straggling, and skewness) for 300 keV protons are shown. The shape of curves are discussed explaining the resonance dechanneling effect and the non-monotonic behaviour of transparency in the case of the axial-to-planar channeling transition

Studies of internal bremsstrahlung spectrum of 35S beta emitter in the photon energy region of 1–100 keV

International Nuclear Information System (INIS)

Singh, Amrit; Dhaliwal, A.S.

2014-01-01

The internal bremsstrahlung (IB) spectral photon distribution, produced by soft beta particles of 35 S (W max =164 keV), in the photon energy region of 1–100 keV, is measured by using a Si(Li) detector, having high energy resolution and efficiency at low energy region. The measured spectral IB photon distribution is compared with KUB theory and Coulomb corrected IB theories given by Nilsson, and Lewis and Ford. After applying the necessary corrections, the experimental and theoretical IB spectral photon distributions are compared in terms of the number of IB photon of energy k per m o c 2 per unit photon yield. In the low energy region (below 10 keV), the experimental results are in agreement with all the theories. However, in photon energy region of 10–50 keV, experimental results are in agreement with Coulomb corrected Nilsson theory only, within the experimental errors. Further, beyond 50 keV, the Nilsson theory is more close to the experimental results than the KUB, and the Lewis and Ford theories. Hence, the Nilsson theory is more accurate than the other theories given by KUB and Lewis and Ford, particularly at a high energy end. The experimental results reported here with Si(Li) detector are free from number of ambiguities in earlier measurements reported with NaI(Tl) and HPGe detectors. The present results are indicating a relook into the theoretical considerations, given by different theories, while taking into account the Coulomb corrections for predicting the IB spectrum, particularly at high photon energy region. - Highlights: • The internal bremsstrahlung spectrum of 35 S beta emitter, in the photon energy region of 1–100 keV. • These measurement are taken by using a Si(Li) detector. • Theoretical and experimental results are reported in terms of number of photons of energy k per m 0 c 2 per unit photon yield. • The Nilsson theory for IB is more accurate than KUB and Lewis and Ford, particularly at high photon energy region

Evaluation of the radiation width of the 27.7 keV resonance in 56Fe

International Nuclear Information System (INIS)

Allen, B.J.

1982-01-01

A critical review is given of measurements of the radiation width of the 27.7 keV resonance in 56 Fe. An evaluation of results yields a recommended value of GAMMA #betta# + 1.00 +- 0.04 eV for this resonance

The low energy particle detector SLED (≅30 keV-3.2 MeV) and its performance on the Phobos mission to Mars and its moons

International Nuclear Information System (INIS)

McKenna-Lawlor, S.; Afonin, V.V.; Gringauz, K.I.; O'Sullivan, D.; Thompson, A.; Somogyi, A.J.; Szabo, L.; Varga, A.

1990-01-01

A low energy particle detector system (SLED) is described which was designed to measure the flux densities of electrons and ions in the energy range from ∝30 keV to a few MeV in (a) the varying solar aspect angles and temperatures pertaining during the Cruise Phase of the Phobos Mission and (b) in the low temperature environment (reaching -25deg C) pertaining during Mars Encounter. Representative data illustrating the excellent functioning of SLED during both phases of the mission are presented. (orig.)

Uranium enrichment measurements without calibration using gamma rays above 100 keV

International Nuclear Information System (INIS)

Ruhter, Wayne D.; Lanier, Robert G.; Hayden, Catherine F.

2001-01-01

Full text: The verification of UF6 shipping cylinders is an important activity in routine safeguards inspections. Current measurement methods using either sodium-iodide or high-purity germanium detectors requires calibrations that are not always appropriate for field measurements, because of changes in geometry or container wall thickness. The introduction of the MGAU code demonstrated the usefulness of intrinsically calibrated measurements for inspections. MGAU uses the 100-keV region of the uranium gamma-ray spectrum. The thick walls of UF6 shipping cylinders preclude the routine use of MGAU for these measurements. We have developed a uranium enrichment measurement method for measurements using high- purity germanium detectors, which do not require calibration and uses uranium gamma rays above 100 keV. The method uses seven gamma rays from U-235 and U-238 to determine their relative detection efficiency intrinsically and with an additional gamma ray from U-234 the relative abundance of these three uranium isotopes. The method uses a function that describes the basic physical processes that predominately determine the relative detection efficiency curve, These are the detector efficiency, the absorption by the cylinder wall, and the self-absorption by the UF6 contents. We will describe this model and its performance on various uranium materials and detector types. (author)

Dose response of thin-film dosimeters irradiated with 80-120 keV electrons

DEFF Research Database (Denmark)

Helt-Hansen, J.; Miller, A.; Sharpe, P.

2005-01-01

Thin-film dosimeters (Riso B3 and alanine films) were irradiated at 10 MeV and 80-120 keV electron accelerators, and it has been shown that the radiation response of the dosimeter materials (the radiation chemical yields) are constant at these irradiation energies. However, dose gradients within ...... are present within the dosimeter. (C) 2005 Elsevier Ltd. All rights reserved....

On the source of the 5-55 keV Heliosphere ENAs measured with Cassini/INCA

Science.gov (United States)

Dialynas, Konstantinos; Roelof, Edmond; Mitchell, Donald; Krimigis, Stamatios; Decker, Robert

2016-07-01

The Low Energy Charged Particle (LECP) in situ measurements from V1 and V2 have revealed a reservoir of ions and electrons that constitute the heliosheath (HS) after crossing the termination shock (TS) 35deg north and 32deg south of the ecliptic plane at 94 and 84 astronomical units (1 AU= 1.5 x10 ^{8} km), respectively. The outer Heliosphere boundary, the Heliopause (HP), has now been determined in the direction of V1 to be at ˜122 AU. The in situ measurements by each Voyager were placed in a global context by remote sensing images using ENA obtained with the Ion and Neutral Camera (INCA) onboard Cassini orbiting Saturn. The ENA images have revealed a 5.2-55 keV hydrogen (H) ENA region (Belt) that loops through the celestial sphere and contributes to balancing the pressure of the interstellar magnetic field (ISMF). Here we address one of the remaining and most important questions: Where do the 5-55 keV ENAs that INCA measures come from? We analyzed INCA all-sky maps from 2003 to 2015 and compare the solar cycle (SC) variation of the ENAs in both the nose (upstream) and anti-nose (downstream) directions with the intensities of > 30 keV ions (source of ENA through charge exchange-CE with H) measured in-situ by V1 and V2, in overlapping energy bands ˜30-55 keV. ENA intensities decrease during the declining phase of SC23 by ˜x3 from 2003 to 2011 but recover through 2014 (SC24); similarly, V1 and V2 ion intensities also decrease and then recover through 2014. The similarity of time profiles of remotely sensed ENA and locally measured ions are consistent with (a) ENA originating in the HS, and (b) the global HS responding promptly (within ˜1-1.5 years) to outward-propagating solar wind changes throughout the SC. Further, recovery of the Belt during SC24 precedes asymmetrically from south to north in the general direction of the nose. This may be related to the non-symmetric evolution of solar coronal holes during SC recovery.

An LCLC resonant topology based filament power supply for 300 KeV DC accelerator

International Nuclear Information System (INIS)

Kasliwal, A.; Gauttam, V.K.; Banwari, R.; Pandit, T.G.; Thakurta, A.C.

2013-01-01

A compact, low energy dc accelerator for industrial applications requiring beam energy in the range of 100 to 300 keV is under development at Raja Ramanna Centre for Advanced Technology, Indore. The accelerator uses an indirectly heated LaB6 disc type filament of 4 mm diameter as an electron emitter which is floating at terminal voltage of the accelerator. A power supply is required to heat the filament for its full range of emission. A high frequency inverter operating at fixed frequency feeds the power to the filament through high frequency transformers and capacitive isolation column. A buck chopper controls the dc bus voltage of the inverter so as to control the terminal voltage of the filament thus controlling the beam current. This paper presents the analysis and design of the filament supply that implements a 40 kHz high order LCLC series parallel resonant inverter that utilizes the reflected capacitance of the HV transformer and capacitive isolation column as its tank circuit component. The operating characteristics and analysis of series resonant (SRC), parallel resonant (PRC) and series parallel (SPRC) resonant converters have been reported for fixed frequency operation. It has been shown that SPRC takes the advantage of both SRC and PRC curtailing their disadvantages. Hence a series parallel LCLC combination has been used as it gives the advantage of low device currents and a better load regulation. (author)

Picosecond x-ray measurements from 100 eV to 30 keV

International Nuclear Information System (INIS)

Attwood, D.T.; Kauffman, R.L.; Stradling, G.L.

1980-01-01

Picosecond x-ray measurements relevant to the Livermore Laser Fusion Program are reviewed. Resolved to 15 picoseconds, streak camera detection capabilities extend from 100 eV to higher than 30 keV, with synchronous capabilities in the visible, near infrared, and ultraviolet. Capabilities include automated data retrieval using charge coupled devices (CCD's), absolute x-ray intensity levels, novel cathodes, x-ray mirror/reflector combinations, and a variety of x-ray imaging devices

A study of molecular correlations observed in the small-angle photon scattering distributions of 60 KeV photons interacting with low-atomic-number media

International Nuclear Information System (INIS)

Bradley, D.A.

1988-01-01

A variant of the multisection filter and annular target geometry, with a designed angular acceptance of +-0.5 0 , has been utilised in measuring accurate, O(5%), absolute total differential scattering cross sections of 60 KeV photons for H 2 O, methyl methacrylate (C 5 H 8 O 2 ) n and nylon-6 (C 12 H 22 O 3 N 2 ) n in the angular scattering range of 2 0 -10 0 . The effects of molecular correlations manifest, to varying degree, in strong forward peaking of the scattered photon distribution. Comparison is made with available experiment and theory [pt

Generalized empirical equation for the extrapolated range of electrons in elemental and compound materials

International Nuclear Information System (INIS)

Lima, W. de; Poli CR, D. de

1999-01-01

The extrapolated range R ex of electrons is useful for various purposes in research and in the application of electrons, for example, in polymer modification, electron energy determination and estimation of effects associated with deep penetration of electrons. A number of works have used empirical equations to express the extrapolated range for some elements. In this work a generalized empirical equation, very simple and accurate, in the energy region 0.3 keV - 50 MeV is proposed. The extrapolated range for elements, in organic or inorganic molecules and compound materials, can be well expressed as a function of the atomic number Z or two empirical parameters Zm for molecules and Zc for compound materials instead of Z. (author)

Proton and electron impact on molecular and atomic oxygen: I. High resolution fluorescence spectra in the visible and VUV spectral range and emission cross-sections for dissociative ionisation and excitation of O2

International Nuclear Information System (INIS)

Wilhelmi, O.; Schartner, K.H.

2000-01-01

For pt.II see ibid., vol.11, p.45-58, 2000. Molecular oxygen O 2 was dissociated in collisions with protons and electrons in the intermediate velocity range (p + -energies: 17-800 keV, e - -energies: 0.2-2 keV). Fluorescence from excited atomic and singly ionised fragments and from singly ionised molecules was detected in the VUV and in the visible and near UV spectral range. Highly resolved spectra are presented for the VUV (46-131 nm) and the near UV/visible (340-605 nm) spectral range. Absolute emission cross-sections have been determined for dissociative ionisation and excitation leading to fluorescence in the VUV. Results are compared with published data. (orig.)

X-ray optics for 50-100 keV undulator radiation using crystals and refractive lenses

International Nuclear Information System (INIS)

Shastri, S. D.; Mashayekhi, A.; Cremer, J. T.; Piestrup, M. A.

2003-01-01

Compound refractive lenses (CRLs) are effective for collimating or focusing high-energy x-ray beams (50 - 100 keV) and can be used in conjunction with crystal optics in a variety of configurations, as demonstrated at the 1-ID undulator beamline of the Advanced Photon Source. As a primary example, this article describes the quadrupling of the output flux when a collimating CRL, composed of cylindrical holes in aluminum, is inserted in between two successive monochromators -- a modest energy resolution premonochromator followed by a high-resolution monochromator. The premonochromator is a cryogenically cooled, divergence-preserving, bent double-Laue Si(111) crystal device delivering an energy width ΔE/E ∼ 10 -3 , sufficient for most experiments. The high-resolution monochromator is a four-reflection, flat Si(111) crystal system resembling two channel-cuts in a dispersive arrangement, reducing the bandwidth to ΔE/E -4 , as required for some applications. Tests with 67 keV and 81 keV photon energies show that the high-resolution monochromator, having a narrow angular acceptance of a few erad, exhibits, a four-fold throughput enhancement due to the insertion of a CRL which reduces the premonochromatized beam's vertical divergence from 29 erad to a few erad. The ability to focus high-energy x-rays with CRLs having long focal lengths (tens of meters) is also shown by creating a line focus of 70 - 90 μ m beam height in the beamline end-station with both the modest-energy-resolution and high-energy- resolution monochromatic x-rays

Design and construction of program frame software of 300 keV/20 mA EBM control panel computerized base

International Nuclear Information System (INIS)

Eko Priyono; Saminto

2015-01-01

The program frame software of computer based control panel for 300 keV/20 mA EBM has been designed and constructed. This software is used for EBM components operating system, EBM operating parameters monitor and control system. This software contain instructions program for acquisition, actuation, process and display operation parameters data which is made by using visual basic V.6. This software displays some menus i.e. cover menu, main menu, sub menu and sub-sub menu. Performance test was done by integrating software and hardware and then operated the EBM via computer device. The test show that data communication between software and hardware was suitable, EBM components can be operated via computer device, EMB operation parameters can be controlled and monitored in form digital number, bar graph and continuous graphics the device can execute properly all instruction output program of 300 keV/20 mA control panel so the device is ready to use as one of computerize operating system of 300 keV/20 mA. (author)

Range measurements and track kinetics in Dielectric Nuclear Track Detectors (DNTDs)

Energy Technology Data Exchange (ETDEWEB)

Aframian, A

1981-01-01

Observations of nuclear track development profiles and the kinetics of etched tracks in sensitive dielectric nuclear track detectors indicate three separate phases: the inception phase or the cone phase, the transition phase and the sphere phase. Continued etching of the sphere phase to through-tracks yields accurate range data for particles of different masses and energies and minimum critical angles of registration for each particle. The present results show an energy resolution of 40 keV (fwhm) for 5.48 MeV alpha-particles emitted from Am-241.

Effects of uranium bombardment by 20-40 KeV argon ions, Annex 2

International Nuclear Information System (INIS)

Nenadovic, T.; Jurela, Z.

1966-01-01

This paper shows the results of argon ions interaction with the polycrystal natural uranium. Thin foil of uranium about 200 μ was bombarded by 20-40 KeV argon ions. Coefficients of cathode scattering δ and secondary electrons emission γ were measured, during the process A + →U. The foil was then studied by transmission method and method of single step replica using an electron microscope [sr

Development of scanning magnet for 750 keV DC accelerator

International Nuclear Information System (INIS)

Pramod, R.; Pankaj Kumar; Venkateswaran, S.V.; Bapna, S.C.

2003-01-01

In the radiation processing technologies, the surface to be irradiated has to be as large as possible, but keeping a good uniformity of the absorbed dose. To attain such a goal, the beam should be scanned in a plane perpendicular on the displacement of the conveyor belt. Therefore, scanning magnets are necessary. A scanning magnet should ensure the homogeneity of the absorbed dose (and, similarly, of the beam current distribution) on the items to be irradiated. In this paper some simple relations needed in the design of the scanning magnets are deduced, the design and fabrication aspects of the scanning magnet for the 750 keV DC accelerator are discussed

Ranges, Reflection and Secondary Electron Emission for keV Hydrogen Ions Incident on Solid N2

DEFF Research Database (Denmark)

Børgesen, P.; Sørensen, H.; Hao-Ming, Chen

1983-01-01

Ranges were measured for 0.67–3.3 keV/amu hydrogen and deuterium ions in solid N2. Comparisons with similar results for N2-gas confirm the previously observed large phase effect in the stopping cross section. Measurements of the secondary electron emission coefficient for bulk solid N2 bombarded...... by 0.67–9 keV/amu ions also seem to support such a phase effect. It is argued that we may also extract information about the charge state of reflected projectiles....

The low energy particle detector SLED ( approx equal 30 keV-3. 2 MeV) and its performance on the Phobos mission to Mars and its moons

Energy Technology Data Exchange (ETDEWEB)

McKenna-Lawlor, S. (Saint Patrick' s Coll., Maynooth (Ireland) Space Technology Ireland Ltd., Maynooth (Ireland)); Afonin, V.V.; Gringauz, K.I. (AN SSSR, Moscow (USSR). Inst. Kosmicheskikh Issledovanij); Keppler, E.; Kirsch, E.; Richter, A.; Witte, M. (Max-Planck-Institut fuer Aeronomie, Katlenburg-Lindau (Germany, F.R.)); O' Sullivan, D.; Thompson, A. (Dublin Inst. for Advanced Studies (Ireland)); Somogyi, A.J.; Szabo, L.; Varga, A. (Hungarian Academy of Sciences, Budapest (Hungary). Central Research Inst. for Physics)

1990-05-01

A low energy particle detector system (SLED) is described which was designed to measure the flux densities of electrons and ions in the energy range from {proportional to}30 keV to a few MeV in (a) the varying solar aspect angles and temperatures pertaining during the Cruise Phase of the Phobos Mission and (b) in the low temperature environment (reaching -25deg C) pertaining during Mars Encounter. Representative data illustrating the excellent functioning of SLED during both phases of the mission are presented. (orig.).

Atomic scattering in the diffraction limit: electron transfer in keV Li+-Na(3s, 3p) collisions

International Nuclear Information System (INIS)

Poel, M van der; Nielsen, C V; Rybaltover, M; Nielsen, S E; Machholm, M; Andersen, N

2002-01-01

We measure angle differential cross sections (DCS) in Li + + Na → Li + Na + electron transfer collisions in the 2.7-24 keV energy range. We do this with a newly constructed apparatus which combines the experimental technique of cold target recoil ion momentum spectroscopy with a laser-cooled target. This setup yields a momentum resolution of 0.12 au, an order of magnitude better angular resolution than previous measurements on this system. This enables us to clearly resolve Fraunhofer-type diffraction patterns in the angle DCS. In particular, the angular width of the ring structure is given by the ratio of the de Broglie wavelength λ dB = 150 fm at a velocity v = 0.20 au and the effective atomic diameter for electron capture 2R = 20 au. Parallel AO and MO semiclassical coupled-channel calculations of the Na(3s, 3p) → Li(2s, 2p) state-to-state collision amplitudes have been performed, and quantum scattering amplitudes are derived by the eikonal method. The resulting angle-differential electron transfer cross sections and their diffraction patterns agree with the experimental level-to-level results over most scattering angles in the energy range

Intensity and anisotropy variations of precipitating particle fluxes with the energy above 30 keV

International Nuclear Information System (INIS)

Altyntseva, V.I.; Dronov, A.V.; Kovtyukh, A.S.; Panasyuk, M.I.; Polekh, N.M.; Rejzman, S.Ya.; Sosnovets, Eh.N.

1982-01-01

Space-time variations of 50-80 keV electron and 210-320 keV proton precipitations during magnetic storm on 29. 07. 77 and magnetic perturbed period (Ksub(p) >= 4) on 8. 04. 77 are compared using the Kosmos 900 satellite data. The structure of electron and proton isotropization regions is significantly different: for electrons isotropic flows are localized in narrow zones inside the precipitation area and for protons they occupy practically the whole precipitation region. The relative position of plasma pause and the proton precipitation region testify also to the effect of magnetosphere convection on the space-time variations of the proton participation. The highest proton precipitation was observed in the evening-night sector and electrons - in the morning-day sector. The proton precipitation region consists of a narrow low-latitudinal zone with the anisotropic pitch-angular distribution and of an extended zone of isotropic flows. The cigar-shaped pitch-angular electron distribution was observed in the auroral area

Scalar field dark matter with spontaneous symmetry breaking and the 3.5 keV line

Science.gov (United States)

Cosme, Catarina; Rosa, João G.; Bertolami, O.

2018-06-01

We show that the present dark matter abundance can be accounted for by an oscillating scalar field that acquires both mass and a non-zero expectation value from interactions with the Higgs field. The dark matter scalar field can be sufficiently heavy during inflation, due to a non-minimal coupling to gravity, so as to avoid the generation of large isocurvature modes in the CMB anisotropies spectrum. The field begins oscillating after reheating, behaving as radiation until the electroweak phase transition and afterwards as non-relativistic matter. The scalar field becomes unstable, although sufficiently long-lived to account for dark matter, due to mass mixing with the Higgs boson, decaying mainly into photon pairs for masses below the MeV scale. In particular, for a mass of ∼7 keV, which is effectively the only free parameter, the model predicts a dark matter lifetime compatible with the recent galactic and extragalactic observations of a 3.5 keV X-ray line.

Making channeling visible: keV noble gas ion trails on Pt(111)

Energy Technology Data Exchange (ETDEWEB)

Redinger, A; Standop, S; Michely, T [II Physikalisches Institut, Universitaet zu Koeln, D-50937 Koeln (Germany); Rosandi, Y; Urbassek, H M, E-mail: urbassek@rhrk.uni-kl.de [Fachbereich Physik und Forschungszentrum OPTIMAS, Universitaet Kaiserslautern, Erwin-Schroedinger-Strasse, D-67663 Kaiserslautern (Germany)

2011-01-15

The impact of argon and xenon noble gas ions on Pt(111) in grazing incidence geometry are studied through direct comparison of scanning tunneling microscopy images and molecular dynamics simulations. The energy range investigated is 1-15 keV and the angles of incidence with respect to the surface normal are between 78.5{sup 0} and 88{sup 0}. The focus of the paper is on events where ions gently enter the crystal at steps and are guided in channels between the top most layers of the crystal. The trajectories of the subsurface channeled ions are visible as trails of surface damage. The mechanism of trail formation is analyzed using simulations and analytical theory. Significant differences between Xe{sup +} and Ar{sup +} projectiles in damage, in the onset energy of subsurface channeling as well as in ion energy dependence of trail length and appearance are traced back to the projectile and ion energy dependence of the stopping force. The asymmetry of damage production with respect to the ion trajectory direction is explained through the details of the channel shape and subchannel structure as calculated from the continuum approximation of the channel potential. Measured and simulated channel switching in directions normal and parallel to the surface as well as an increase of ions entering into channels from the perfect surface with increasing angles of incidence are discussed.

MULTI-KEV X-Ray Yields From High-Z Gas Targets Fielded At Omega

International Nuclear Information System (INIS)

Kane, J.O.; Fournier, K.B.; May, M.J.; Colvin, J.D.; Thomas, C.A.; Marrs, R.E.; Compton, S.M.; Moody, J.D.; Bond, E.J.; Davis, J.F.

2010-01-01

The authors report on modeling of x-ray yield from gas-filled targets shot at the OMEGA laser facility. The OMEGA targets were 1.8 mm long, 1.95 mm in diameter Be cans filled with either a 50:50 Ar:Xe mixture, pure Ar, pure Kr or pure Xe at ∼ 1 atm. The OMEGA experiments heated the gas with 20 kJ of 3ω (∼ 350 nm) laser energy delivered in a 1 ns square pulse. the emitted x-ray flux was monitored with the x-ray diode based DANTE instruments in the sub-keV range. Two-dimensional x-ray images (for energies 3-5 keV) of the targets were recorded with gated x-ray detectors. The x-ray spectra were recorded with the HENWAY crystal spectrometer at OMEGA. Predictions are 2D r-z cylindrical with DCA NLTE atomic physics. Models generally: (1) underpredict the Xe L-shell yields; (2) overpredict the Ar K-shell yields; (3) correctly predict the Xe thermal yields; and (4) greatly underpredict the Ar thermal yields. However, there are spreads within the data, e.g. the DMX Ar K-shell yields are correctly predicted. The predicted thermal yields show strong angular dependence.

Deuteron polarizability and S-wave π+d scattering at energies below 1 keV

International Nuclear Information System (INIS)

Pupyshev, V.V.

1987-01-01

The influence of deuteron polarizability on the S-wave π + d-scattering in a low-energy limit is explored in the framework of the variable phase method. It is shown that the nonoscillating part of the S-wave cross section of π + d-scattering has a deep and sharp minimum in the energy region ∼ 0.4 keV

Measurements of energy losses, distributions of energy loss and additivity of energy losses for 50 to 150 keV protons in hydrogen and nine hydrocarbon gases

International Nuclear Information System (INIS)

Thorngate, J.H.

1976-05-01

Measurements of energy-loss distributions were made for 51, 102, and 153 keV protons traversing hydrogen, methane, ethyne (acetylene), ethene (ethylene), ethane, propyne (methyl acetylene), propadiene (allene), propene (propylene), cyclopropane and propane. The objectives were to test the theories of energy-loss distribution in this energy range and to see if the type of carbon bonding in a hydrocarbon molecule affects the shape of the distribution. Stopping powers and stopping cross sections were also measured at these energies and at 76.5 and 127.5 keV to determine effects of chemical binding. All of the measurements were made at the gas density required to give a 4 percent energy loss. The mean energy, second central moment (a measure of the width of the distribution), and the third central moment (a measure of the skew) were calculated from the measured energy-loss distributions. Stopping power values, calculated using the mean energy, compared reasonably well with those calculated from the Bethe stopping power theory. For the second and third central moments, the best agreement between measurement and theory was when the classical scattering probability was used for the calculations, but even these did not agree well. In all cases, variations were found in the data that could be correlated to the type of carbon binding in the molecule. The differences were statistically significant at a 99 percent confidence interval for the stopping powers and second central moments measured with 51 keV protons. Similar trends were noted at other energies and for the third central moment, but the differences were not statistically significant at the 99 percent confidence interval

M-shell X-ray production cross-sections for elements with 67 ≤ Z ≤ 92 at incident photon energies EM1inc≤150keV

International Nuclear Information System (INIS)

Chauhan, Yogeshwar; Kumar, Anil; Puri, Sanjiv

2009-01-01

The X-ray production cross-sections for the Mk (k = ξ, δ, α, β, ζ, γ, m 1 and m 2 ) groups of X-rays have been evaluated for all the elements with 67 ≤ Z ≤ 92 at incident photon energies ranging E M 1 inc ≤150 keV using currently available theoretical data sets of different physical parameters, namely, partial photoionization cross-sections, X-ray emission rates, fluorescence and Coster-Kronig yields, and the K-shell/L j (j = 1-3) subshell to the M i (i = 1-5) subshell vacancy transfer probabilities, based on the independent particle models.

Double and single ionization of helium by 58-keV X-rays

International Nuclear Information System (INIS)

Spielberger, L.; Buslaps, T.; Braeuning, H.; Gemmell, D.S.; Schmidt-Boecking, H.

1996-03-01

We have measured the ratio of cross sections for double to single ionization of helium by Compton scattering, R c =σ c ++ /σ c + at a photon energy of 58 keV using Cold Target Recoil Ion Momentum Spectroscopy. We find a value R c =(0.84 -11 +08 )% that is in agreement with the asymptotic limits predicted by Andersson and Burgdoerfer (Phys. Rev. A 50, R2810 (1994)) and Suric et al. (Phys. Rev. Lett. 73, 790 (1994)). (orig.)

Use of proportional counter in X-Ray spectrometry between 5 and 100 keV. Application to the detection of fission products and to the determination of absolute X-Ray disintegration rates; Utilisation d'un compteur proportionnel en spectrometrie de rayons X entre 5 et 100 keV. Application a la detection des produits de fission et a la determination des taux d'emission X absolus

Energy Technology Data Exchange (ETDEWEB)

Cerf, J [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

1969-07-01

The measurement of electromagnetic radiations is difficult in the energy range 20-100 keV. We made suitable for this purpose a regular proportional counter, modifying both the nature and pressure of the gaseous mixture filling the detector volume. We selected the CPEN-SAIP counter, which is able to withstand such modifications. In the energy range considered, the counter is to be standardized with radioactive sources. Such standards were selected according to their disintegration schemes. We thus defined the conditions of use (resolution, yield) of the CPN counter, filled with an argon-methane mixture under a pressure of about 3 bars, in the energy range 5-100 keV. With such an equipment, we were able to measure the absolute disintegration rate for the X-rays of 133 Ba and 75 Se, then to perform the study of a mixed fission products sample. In the same way, we used xenon-based gaseous mixtures, in order to improve the detector yield; in the later case, we carefully examined the limitations introduced by the presence of many parasite rays emitted by the gas. We thus displayed in addition to the leakage peak, the fluorescence ray of the gas, whose origin is difficult to explain. (author) [French] La mesure des rayonnements electromagnetiques est difficile dans une bande d'energie comprise entre 20 et 100 keV environ. Nous avons rendu utilisable, a cet effet, un compteur proportionnel existant en modifiant la nature et la pression du melange gazeux constituant le volume detecteur. De par sa construction, le compteur CPXN, fabrique par les Etablissements S.A.I.P., rend ces experiences possibles. C'est pourquoi nous l'avons choisi. Dans le domaine d'energie consideree l'etalonnage du compteur necessite l'emploi de sources radioactives. Pour les preparer, nous sommes amenes a choisir les radio-nucleides utilisables par l'etude de leur schema de desintegration. Ainsi, nous avons defini les conditions d'utilisation (resolution, efficacite) du compteur CPNX rempli d

Measurement of the -3 keV resonance in the {sup 13}C({alpha},n){sup 16}O reaction and its influence on the synthesis of s-process nuclei

Energy Technology Data Exchange (ETDEWEB)

La Cognata, M.; Spitaleri, C.; Trippella, O.; Kiss, G. G.; Rogachev, G. V.; Mukhamedzhanov, A. M.; Avila, M.; Guardo, G. L.; Koshchiy, E.; Kuchera, A.; Lamia, L.; Puglia, S. M. R.; Romano, S.; Santiago, D.; Sparta, R. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Catania (Italy); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Catania (Italy) and Dipartimento di Fisica e Astronomia, Universita di Catania, Catania (Italy); and others

2012-11-20

The {sup 13}C({alpha},n){sup 16}O reaction is the neutron source for the main component of the s-process, responsible of the production of most nuclei in the mass range 90 < A < 204. It is active inside the helium-burning shell in asymptotic giant branch stars, at temperatures < 10{sup 8} K, corresponding to an energy interval where the {sup 13}C({alpha},n){sup 16}O is effective of 140 - 230 keV. In this region, the astrophysical S(E)-factor is dominated by the -3 keV sub-threshold resonance due to the 6.356 MeV level in {sup 17}O, giving rise to a steep increase of the S-factor. Notwithstanding that it plays a crucial role in astrophysics, no direct measurements exist. Therefore, we have applied the Trojan Horse Method (THM) to the {sup 13}C({sup 6}Li,n{sup 16}O)d quasi-free reaction to achieve an experimental estimate of such contribution. For the first time, the ANC for the 6.356 MeV level has been deduced through the THM as well as the n-partial width, allowing to attain an unprecedented accuracy in the {sup 13}C({alpha},n){sup 16}O study. Though a larger ANC for the 6.356 MeV level is measured, our experimental S(E) factor agrees with the most recent extrapolation in the literature in the 140 - 230 keV energy interval, the accuracy being greatly enhanced thanks to this innovative approach.

Comparative Investigation of Ce3+ Doped Scintillators in a Wide Range of Photon Energies Covering X-ray CT, Nuclear Medicine and Megavoltage Radiation Therapy Portal Imaging Applications

Science.gov (United States)

Valais, Ioannis G.; Michail, Christos M.; David, Stratos L.; Liaparinos, Panagiotis F.; Fountos, George P.; Paschalis, Theodoros V.; Kandarakis, Ioannis S.; Panayiotakis, George S.

2010-02-01

The aim of the present work is to study the performance of scintillators currently used in PET and animal PET systems, under conditions met in radiation therapy and PET/CT imaging. The results of this study will be useful in applications where both CT and PET photons as well as megavoltage cone beam CT (MV CBCT) photons could be detected using a common detector unit. To this aim crystal samples of GSO, LSO, LYSO, LuYAP and YAP scintillators, doped with cerium (Ce+3) were examined under a wide energy range of photon energies. Evaluation was performed by determining the absolute luminescence efficiency (emitted light flux over incident X-ray exposure) in the energy range employed in X-ray CT, in Nuclear Medicine (70 keV up to 662 keV) and in radiotherapy 6 MV (approx. 2.0 MeV mean energy)-18 MV (approx. 4.5 MeV mean energy). Measurements were performed using an experimental set-up based on a photomultiplier coupled to a light integration sphere. The emission spectrum under X-ray excitation was measured, using an optical grating monochromator, to determine the spectral compatibility to optical photon detectors incorporated in medical imaging systems. Maximum absolute luminescence efficiency values were observed at 70 keV for YAP:Ce and LuYAP:Ce and at 140 keV for LSO:Ce, LYSO:Ce and GSO:Ce. Highest absolute efficiency between the scintillators examined was observed for LSO:Ce, followed by LYSO:Ce. The detector optical gain (DOG) exhibited a significant variation with the increase of energy between 70 keV to 2.0 MeV. All scintillators exhibited low compatibility when combined with GaAsP (G5645) photodetector.

Improving accuracy and reliability of 186-keV measurements for unattended enrichment monitoring

International Nuclear Information System (INIS)

Ianakiev, Kiril D.; Boyer, Brian D.; Swinhoe, Martyn T.; Moss, Cal E.; Goda, Joetta M.; Favalli, Andrea; Lombardi, Marcie; Paffet, Mark T.; Hill, Thomas R.; MacArthur, Duncan W.; Smith, Morag K.

2010-01-01

Improving the quality of safeguards measurements at Gas Centrifuge Enrichment Plants (GCEPs), whilst reducing the inspection effort, is an important objective given the number of existing and new plants that need to be safeguarded. A useful tool in many safeguards approaches is the on-line monitoring of enrichment in process pipes. One aspect of this measurement is a simple, reliable and precise passive measurement of the 186-keV line from 235 U. (The other information required is the amount of gas in the pipe. This can be obtained by transmission measurements or pressure measurements). In this paper we describe our research efforts towards such a passive measurement system. The system includes redundant measurements of the 186-keV line from the gas and separately from the wall deposits. The design also includes measures to reduce the effect of the potentially important background. Such an approach would practically eliminate false alarms and can maintain the operation of the system even with a hardware malfunction in one of the channels. The work involves Monte Carlo modeling and the construction of a proof-of-principle prototype. We will carry out experimental tests with UF 6 gas in pipes with and without deposits in order to demonstrate the deposit correction.

R-matrix analysis of the 239Pu cross sections up to 1 keV

International Nuclear Information System (INIS)

Derrien, H.; de Saussure, G.; Perez, R.B.; Larson, N.M.; Macklin, R.L.

1986-06-01

The results are reported of an R-matrix resonance analysis of the 239 Pu neutron cross sections up to 1 keV. After a description of the method of analysis the nearly 1600 resonance parameters obtained are listed and extensive graphical and numerical comparisons between calculated and measured cross-section and transmission date are presented. 47 refs., 47 figs., 8 tabs

Compton scattering study of electron momentum distribution in lithium fluoride using 662 keV gamma radiations

Science.gov (United States)

Vijayakumar, R.; Shivaramu; Ramamurthy, N.; Ford, M. J.

2008-12-01

Here we report the first ever 137Cs Compton spectroscopy study of lithium fluoride. The spherical average Compton profiles of lithium fluoride are deduced from Compton scattering measurements on poly crystalline sample at gamma ray energy of 662 keV. To compare the experimental data, we have computed the spherical average Compton profiles using self-consistent Hartree-Fock wave functions employed on linear combination of atomic orbital (HF-LCAO) approximation. The directional Compton profiles and their anisotropic effects are also calculated using the same HF-LCAO approximation. The experimental spherical average profiles are found to be in good agreement with the corresponding HF-LCAO calculations and in qualitative agreement with Hartree-Fock free atom values. The present experimental isotropic and calculated directional profiles are also compared with the available experimental isotropic and directional Compton profiles using 59.54 and 159 keV γ-rays.

Effective atomic numbers and electron densities of bacteriorhodopsin and its comprising amino acids in the energy range 1 keV–100 GeV

Energy Technology Data Exchange (ETDEWEB)

Ahmadi, Morteza; Lunscher, Nolan [Waterloo Institute for Nanotechnology and Department of Systems Design Engineering, University of Waterloo, 200 University Ave., W., Waterloo, Ontario, Canada N2L 3G1 (Canada); Yeow, John T.W., E-mail: jyeow@uwaterloo.ca [Waterloo Institute for Nanotechnology and Department of Systems Design Engineering, University of Waterloo, 200 University Ave., W., Waterloo, Ontario, Canada N2L 3G1 (Canada)

2013-04-01

Recently, there has been an interest in fabrication of X-ray sensors based on bacteriorhodopsin, a proton pump protein in cell membrane of Halobacterium salinarium. Therefore, a better understanding of interaction of X-ray photons with bacteriorhodopsin is required. We use WinXCom program to calculate the mass attenuation coefficient of bacteriorhodopsin and its comprising amino acids for photon energies from 1 keV to 100 GeV. These amino acids include alanine, arginine, asparagine, aspartic acid, glutamine, glutamic acid, glycine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, Asx1, Asx2, Glx1 and Glx2. We then use that data to calculate effective atomic number and electron densities for the same range of energy. We also emphasize on two ranges of energies (10–200 keV and 1–20 MeV) in which X-ray imaging and radiotherapy machines work.

High-energy X-ray diffraction studies of short- and intermediate-range structure in oxide glasses

International Nuclear Information System (INIS)

Suzuya, Kentaro

2002-01-01

The feature of high-energy X-ray diffraction method is explained. The oxide glasses studies by using BL04B2, high-energy X-ray diffraction beam line of SPring-8, and the random system materials by high-energy monochromatic X-ray diffraction are introduced. An advantage of third generation synchrotron radiation is summarized. On SPring-8, the high-energy X-ray diffraction experiments of random system are carried out by BL04B2 and BL14B1 beam line. BL04B2 can select Si (111)(E=37.8 keV, λ=0.033 nm) and Si(220)(E=61.7 keV, λ=0.020 nm) as Si monochromator. The intermediate-range structure of (MgO) x (P 2 O 5 ) 1-x glass ,MgP 2 O 6 glass, B 2 O 3 glass, SiO 2 and GeO 2 are explained in detail. The future and application of high-energy X-ray diffraction are stated. (S.Y.)

THE HIGH-ENERGY EMISSION OF THE CRAB NEBULA FROM 20 keV TO 6 MeV WITH INTEGRAL SPI

International Nuclear Information System (INIS)

Jourdain, E.; Roques, J. P.

2009-01-01

The SPI spectrometer aboard the International Gamma-Ray Astrophysics Laboratory mission regularly observes the Crab Nebula since 2003. We report on observations distributed over 5.5 years and investigate the variability of the intensity and spectral shape of this remarkable source in the hard X-rays domain up to a few MeV. While single power-law models give a good description in the X-ray domain (mean photon index ∼ 2.05) and MeV domain (photon index ∼ 2.23), crucial information is contained in the evolution of the slope with energy between these two values. This study has been carried out through individual observations and long duration (∼ 400 ks) averaged spectra. The stability of the emission is remarkable and excludes a single power-law model. The slopes measured below and above 100 keV agree perfectly with the last values reported in the X-ray and MeV regions, respectively, but without indication of a localized break point. This suggests a gradual softening in the emission around 100 keV and thus a continuous evolution rather than an actual change in the mechanism parameters. In the MeV region, no significant deviation from the proposed power-law model is visible up to 5-6 MeV. Finally, we take advantage of the spectroscopic capability of the instrument to seek for previously reported spectral features in the covered energy range with negative results for any significant cyclotron or annihilation emission on 400 ks timescales. Beyond the scientific results, the performance and reliability of the SPI instrument is explicitly demonstrated, with some details about the most appropriate analysis method.

Investigation of the effective atomic numbers of dosimetric materials for electrons, protons and alpha particles using a direct method in the energy region 10 keV-1 GeV: a comparative study.

Science.gov (United States)

Kurudirek, Murat; Aksakal, Oğuz; Akkuş, Tuba

2015-11-01

A direct method has been used for the first time, to compute effective atomic numbers (Z eff) of water, air, human tissues, and some organic and inorganic compounds, for total electron proton and alpha particle interaction in the energy region 10 keV-1 GeV. The obtained values for Z eff were then compared to those obtained using an interpolation procedure. In general, good agreement has been observed for electrons, and the difference (%) in Z eff between the results of the direct and the interpolation method was found to be energy range from 10 keV to 1 MeV. More specifically, results of the two methods were found to agree well (Dif. energy region with respect to the total electron interaction. On the other hand, values for Z eff calculated using both methods for protons and alpha particles generally agree with each other in the high-energy region above 10 MeV.

A study on the microstructural parameters of 550 keV electron irradiated Lexan polymer films

International Nuclear Information System (INIS)

Hareesh, K.; Pramod, R.; Petwal, V. C.; Dwivedi, Jishnu; Sangappa; Sanjeev, Ganesh

2012-01-01

Lexan polymer films irradiated with 550 keV Electron Beam (EB) were characterized using Wide Angle Xray Scattering (WAXS) data to study the microstructural parameters. The crystal imperfection parameters like crystal size , lattice strain (g in %) and enthalpy (α) have been determined by Line Profile Analysis (LPA) using Fourier method of Warren.

Evolution of substorm and quiet-time electron anisotropies (30 less than or equal to E/sub e/ less than or equal to 300 keV)

International Nuclear Information System (INIS)

Higbie, P.R.; Baker, D.N.; Belian, R.D.; Hones, E.W. Jr.

1979-01-01

Work using the Charged Particle Analyzer (CPA) instruments aboard spacecraft 1976-059A and 1977-007A in synchronous orbit has shown that approx. 30 keV electron anisotropies may act as a sensitive indicator of the buildup of stresses in the outer magnetosphere. The development of such stresses is evidenced in the premidnight sector by the formation of field-aligned (cigar) anisotropies in the 30 keV electrons one to two hours prior to the onset of the expansion phase of the substorm. Using the complete three-dimensional pitch angle measurement capability of the CPA, it is shown in a movie format the detailed development of electron anisotropies during the course of substorm growth, expansion, and recovery phases. In contrast, detailed examples of quiet-time behavior of electron anisotropies at several energy levels between 30 and 300 keV are also shown. Such periods with no substorm activity show that 30 keV electrons remain approx. isotropic (outside the loss cone) throughout the nighttime sector, even though the higher energy (> 100 keV) electrons show the development of cigar anisotropies associated with normal drift-shell splitting. These results emphasize the substorm predictive capabilities of the low energy electron anisotropies and illustrate how the data might be used in a real-time monitoring mode. 19 references

The dynamic range of ultra-high-resolution cryogenic gamma-ray spectrometers

Energy Technology Data Exchange (ETDEWEB)

Ali, Shafinaz [Advanced Detector Group, Lawrence Livermore National Laboratory, 7000 East Avenue, L-270, Livermore, CA 94550 (United States); Terracol, Stephane F. [Advanced Detector Group, Lawrence Livermore National Laboratory, 7000 East Avenue, L-270, Livermore, CA 94550 (United States); Drury, Owen B. [Advanced Detector Group, Lawrence Livermore National Laboratory, 7000 East Avenue, L-270, Livermore, CA 94550 (United States); Friedrich, Stephan [Advanced Detector Group, Lawrence Livermore National Laboratory, 7000 East Avenue, L-270, Livermore, CA 94550 (United States)]. E-mail: friedrich1@llnl.gov

2006-04-15

We are developing high-resolution cryogenic gamma-ray spectrometers for nuclear science and non-proliferation applications. The gamma-ray detectors are composed of a bulk superconducting Sn foil absorber attached to a multilayer Mo/Cu transition-edge sensor (TES). The energy resolution of a detector with a 1x1x0.25 mm{sup 3} Sn absorber is 50-90 eV FWHM for {gamma}-rays up to 100 keV, and it decreases for larger absorbers. Here, we present the detector performance for different absorber volumes, and discuss the trade-offs between energy resolution and dynamic range.

The Dynamic Range of Ultra-High Resolution Cryogenic Gamma-ray Spectrometers

International Nuclear Information System (INIS)

Ali, S; Terracol, S F; Drury, O B; Friedrich, S

2005-01-01

We are developing high-resolution cryogenic gamma-ray spectrometers for nuclear science and non-proliferation applications. The gamma-ray detectors are composed of a bulk superconducting Sn foil absorber attached to multilayer Mo/Cu transition-edge sensors (TES). The energy resolution achieved with a 1 x 1 x 0.25 mm 3 Sn absorber is 50 -90eV for γ-rays up to 100 keV and it decreases for large absorber sizes. We discuss the trade-offs between energy resolution and dynamic range, as well as development of TES arrays for higher count rates and better sensitivity

Measurements of Lα, Lβ X-ray production cross sections of Bi by 17-40 keV electron impact

International Nuclear Information System (INIS)

Wu, Y.; An, Z.; Duan, Y.M.; Liu, M.T.

2010-01-01

We present results of measurements of L α , L β X-ray production cross sections for the element Bi (Z = 83) by 17-40 keV electron impact. The target used in the experiment was prepared by evaporating the element Bi to the thick pure carbon substrate. The effects of multiple scattering of electrons when penetrating the target film, of electrons reflected from the thick pure carbon substrate and of bremsstrahlung photons produced by the impact of incident electrons on the target are corrected by means of Monte Carlo simulation. The experimental data, reported here for the first time in the energy region of 17-40 keV, are compared with the DWBA theory and the PWBA-C-Ex theory. They are in good agreement.

OPTIMIZATION OF OPERATION PARAMETERS OF 80-KEV ELECTRON GUN

Directory of Open Access Journals (Sweden)

JEONG DONG KIM

2014-06-01

As a first step, the electron generator of an 80-keV electron gun was manufactured. In order to produce the high beam power from electron linear accelerator, a proper beam current is required form the electron generator. In this study, the beam current was measured by evaluating the performance of the electron generator. The beam current was determined by five parameters: high voltage at the electron gun, cathode voltage, pulse width, pulse amplitude, and bias voltage at the grid. From the experimental results under optimal conditions, the high voltage was determined to be 80 kV, the pulse width was 500 ns, and the cathode voltage was from 4.2 V to 4.6 V. The beam current was measured as 1.9 A at maximum. These results satisfy the beam current required for the operation of an electron linear accelerator.

Sputtering of thin benzene and polystyrene overlayers by keV Ga and C60 bombardment

International Nuclear Information System (INIS)

Czerwinski, B.; Delcorte, A.; Garrison, B.J.; Samson, R.; Winograd, N.; Postawa, Z.

2006-01-01

The mechanisms of ion-stimulated desorption of thin organic overlayers deposited on metal substrates by mono- and polyatomic projectiles are examined using molecular dynamics (MD) computer simulations. A monolayer of polystyrene tetramers (PS4) physisorbed on Ag{1 1 1} is irradiated by 15 keV Ga and C 60 projectiles at normal incidence. The results are compared with the data obtained for a benzene overlayer to investigate the differences in sputtering mechanisms of weakly and strongly bound organic molecules. The results indicate that the sputtering yield decreases with the increase of the binding energy and the average kinetic energy of parent molecules is shifted toward higher kinetic energy. Although the total sputtering yield of organic material is larger for 15 keV C 60 , the impact of this projectile leads to a significant fragmentation of ejected species. As a result, the yield of the intact molecules is comparable for C 60 and Ga projectiles. Our data indicate that chemical analysis of the very thin organic films performed by detection of sputtered neutrals will not benefit from the use of C 60 projectiles

Investigation of the 800 keV Peak in the Gamma Spectrum of Swedish Laplanders

Energy Technology Data Exchange (ETDEWEB)

Andersson, I Oe; Nilsson, I; Eckerstig, K

1962-08-15

The gamma spectrum of the body radioactivity in reindeer raising Laplanders has shown a peak at 800 keV, which has not been discussed before in connection with whole body counting. We present here an investigation that was made to be able to identify the isotope. The result is that the peak comes from cesium 134. The possibility to find cesium 134 in fallout is discussed.

Investigation of the 800 keV Peak in the Gamma Spectrum of Swedish Laplanders

International Nuclear Information System (INIS)

Andersson, I.Oe.; Nilsson, I.; Eckerstig, K.

1962-08-01

The gamma spectrum of the body radioactivity in reindeer raising Laplanders has shown a peak at 800 keV, which has not been discussed before in connection with whole body counting. We present here an investigation that was made to be able to identify the isotope. The result is that the peak comes from cesium 134. The possibility to find cesium 134 in fallout is discussed

Study of the Jet-Pini 160 keV optics in a single beamlet system

International Nuclear Information System (INIS)

Bottiglioni, F.; Bussac, J.P.; Jequier, F.

1986-01-01

The optics of the prototype of the extended performances PINI-injector, for the operation at 160 keV in D 2 , has been studied and tested on the separate test stand L.E.O., enabling experiments on a single beamlet. The results of the optics computations and of the experimentation on the beamlet are presented and discussed, namely as far profiles, divergence and steering are concerned

Single-electron capture into Ar+ excited states in Ar2 + Na collision below 12 keV, 1

International Nuclear Information System (INIS)

Matsumoto, Atsushi; Tsurubuchi, Seiji; Okuno, Kazuhiko; Ohtani, Shunsuke; Iwai, Tsuruji.

1979-08-01

Emission spectra between 2800 and 6000 A have been observed at the ionic energies from 0.2 to 12 keV. Absolute measurements of emission cross-sections have been made for the emission lines coming from ArII excited states at 4 and 8 keV with a crossed-beam technique. Processes of single-electron capture into the ArII 4p- and 4p'-states, with exothermicity of a few eV, take place dominantly (--10 15 cm 2 ), while the endothermic processes producing ArII in the 4d- and 5s-states occur with small cross-sections. Sum of the cross-sections for electron capture into the excited states observed is comparable with the total single-electron capture cross-section estimated from attenuation measurements of ion currents. Possible errors and uncertainties are discussed. (author)

Single-electron capture into Ar+ excited states in Ar2++Na collision below 12 keV, 1

International Nuclear Information System (INIS)

Matsumoto, Atsushi; Tsurubuchi, Seiji; Iwai, Tsuruji; Ohtani, Shunsuke; Okuno, Kazuhiko

1980-01-01

Emission spectra between 2800 and 6000 A have been observed at the ionic energies from 0.2 to 12 keV. Absolute measurements of emission cross-sections have been made for the emission lines coming from ArII excited states at 4 and 8 keV with a crossed-beam technique. Processes of single-electron capture into the ArII 4p- and 4p'-states, with exothermicity of a few eV, take place dominantly (--10 -15 cm 2 ), while the endothermic processes producing ArII in the 4d- and 5s-states occur with small cross-sections. Sum of the cross-sections for electron capture into the excited states observed is comparable with the total single-electron capture cross-section estimated from attenuation measurements of ion currents. Possible errors and uncertainties are discussed. (author)

Design, development and operational experience of radio frequency (RF) power systems/technologies for LEHIPA and 400 keV RFQ

International Nuclear Information System (INIS)

Pande, Manjiri; Shrotriya, Sandip; Patel, Niranjan

2015-01-01

The important technology development for ion accelerators of 'accelerator driven sub critical reactor system (ADS) is being done under the program of Department of Atomic Energy (DAE). In BARC (BARC) of DAE, technology development of 400 keV radio frequency quadrupole (RFQ) accelerator is done and a 20 MeV - low energy high intensity proton accelerator (LEHIPA) is under development. A 400 KeV deuteron RFQ accelerator is already developed at BARC and its 60 kW radio frequency (RF) power system required for beam acceleration has been designed, developed and tested both in CW mode and in pulse mode for full power of 60 leW. It has been successfully integrated with RFQ via 6-1/8'', 50 ohm RF transmission line, to accelerate proton beam up to 200 KeV energy and deuteron beam to 400 KeV energy. LEHIPA requires about 3 MW of RF power for its operation. So, three 1 MW, 352 MHz RF systems based on klystron will be developed for RFQ and two DTLs. The klystron based RF system for 3 MeV RFQ is under commissioning. Its various subsystems like energy less and insulated gate bipolar transistor (IGBT) based high voltage and low voltage bias supplies, a critical and fast protection and control system - handling various types of field signals, fast acting hard wired instrumentation circuits for critical signals, 100 kV crowbar with its circuits, pulsing circuits and RF circuits have been successfully designed, developed and integrated with klystron. Latest technology development of solid state RF amplifiers at 325 MHz and 350 MHz for normal and super conducting accelerators has attained a certain power level. This paper will discuss all these high power RF systems in detail. (author)

Effect of irradiation with <200 keV electrons on AG-80 resin

Energy Technology Data Exchange (ETDEWEB)

Gao Yu [School of Materials Science and Engineering, Harbin Institute of Technology, 432 Heilongjiang province, Harbin 150001 (China)]. E-mail: czq04@yahoo.com.cn; Jiang Shengling [College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Sun Mingren [School of Materials Science and Engineering, Harbin Institute of Technology, 432 Heilongjiang province, Harbin 150001 (China); Yang Dezhuang [School of Materials Science and Engineering, Harbin Institute of Technology, 432 Heilongjiang province, Harbin 150001 (China); He Shiyu[School of Materials Science and Engineering, Harbin Institute of Technology, 432 Heilongjiang province, Harbin 150001 (China); Li Zhijun [39th Institute, China Electronic Science and Technology Groups Inc., Xi-an 710065 (China)

2005-08-01

AG-80 resin, namely tetraglycidyl diaminodiphenyl methane (TGDDM), is a new type of thermosetting matrix for advanced carbon/epoxy composites, which was irradiated with electrons of 160 keV. The results show that by increasing the fluence to 6.3x10{sup 15} cm{sup -2}, the mass loss ratio ascends dramatically and then tends to level off. The mass loss behavior can be attributed to the combined effects of the formation of gaseous radiolytic products and a degraded layer, the surface ablation due to discharging and the skin carbon enrichment.

500 keV, 10 kW DC electron accelerator at BRIT, Vashi

International Nuclear Information System (INIS)

Sharma, D.K.; Rajan, R.N.; Bakhtsingh, R.I.; Acharya, S.; Rajawat, R.K.

2017-01-01

The 500 keV DC accelerator was indigenously designed and developed by Accelerator and Pulse Power Division, BARC during 1994-97 and commissioned at REPF Hall, BRIT, Vashi on 10"t"h August, 1998. The accelerator operation at 3kW beam power for 8 hour shifts was established in February 2001, confirming to industrial standards for EB treatment of plastic sheets as well as various surface-treatment processes for value addition of the products and materials. Since then, this EB facility is functional and being regularly utilized for various applications

Search of a cyclotron line at 70 keV from Crab Nebula

International Nuclear Information System (INIS)

Ubertini, P.; Bazzano, A.; La Padula, C.D.; Polcaro, V.F.

1980-01-01

An observation of Crab Nebula was made during a transmediterranean balloon flight launched on August 26, 1979 from Milo Base. The hard x-ray experiment carried a payload consisting of two multiwire proportional counters having a geometric area of 900 cm 2 each. A single transit scan of the source was performed on the Crab Nebula region at a float altitude of 2.9 mbs. The preliminary results indicate the existence of an excess flux between 64 - 76 keV above the expected value of Esup(-2.0) power law

Search of a cyclotron line at 70 keV from Crab Nebula

International Nuclear Information System (INIS)

Ubertini, P.; Bazzano, A.; La Padula, C.D.; Polcaro, V.F.

1980-01-01

An observation of Crab Nebula was made during a transmediterranean balloon flight launched on August 26, 1979 from Milo Base (Sicily, Italy). The hard X-ray experiment (HXR 79) carried a payload consisting of two multiwire proportional counters having a geometric area of 900 cm 2 each. A single transit scan of the source was performed on the Crab Nebula region at a float altitude of 2.9 mbs. The preliminary results indicate the existence of an excess flux between 64 - 76 KeV above the expected value of Esup(-2.0) power law. (Auth.)

Measurement of the 234U(n, f ) cross-section with quasi-monoenergetic beams in the keV and MeV range using a Micromegas detector assembly

Science.gov (United States)

Stamatopoulos, A.; Kanellakopoulos, A.; Kalamara, A.; Diakaki, M.; Tsinganis, A.; Kokkoris, M.; Michalopoulou, V.; Axiotis, M.; Lagoyiannis, A.; Vlastou, R.

2018-01-01

The 234U neutron-induced fission cross-section has been measured at incident neutron energies of 452, 550, 651 keV and 7.5, 8.7, 10 MeV using the 7Li ( p, n) and the 2H( d, n) reactions, respectively, relative to the 235U( n, f ) and 238U( n, f ) reference reactions. The measurement was performed at the neutron beam facility of the National Center for Scientific Research "Demokritos", using a set-up based on Micromegas detectors. The active mass of the actinide samples and the corresponding impurities were determined via α-spectroscopy using a surface barrier silicon detector. The neutron spectra intercepted by the actinide samples have been thoroughly studied by coupling the NeuSDesc and MCNP5 codes, taking into account the energy and angular straggling of the primary ion beams in the neutron source targets in addition to contributions from competing reactions ( e.g. deuteron break-up) and neutron scattering in the surrounding materials. Auxiliary Monte Carlo simulations were performed making combined use of the FLUKA and GEF codes, focusing particularly on the determination of the fission fragment detection efficiency. The developed methodology and the final results are presented.

Resonance neutron capture in 23Na and 27Al from 3 to 600 keV

International Nuclear Information System (INIS)

Musgrove, A.R. de L.; Allen, B.J.; Macklin, R.L.

1978-01-01

The radiative capture cross sections of 23 Na and 27 Al were measured with the high resolution facility at the 40 m station of the Oak Ridge Electron Linear Accelerator. Resonance parameters for the individual resonances below 600 keV are given. Particular care was taken to correct the data for prompt neutron scattering effects by Monte Carlo methods

WE-E-BRE-08: Impact of IUdR in Rat 9L Glioma Cell Survival for 25–35 KeV Photo-Activated Auger Electron Therapy

Energy Technology Data Exchange (ETDEWEB)

Alvarez, D; Hogstrom, K [Louisiana State University, Baton Rouge, LA (United States); Mary Bird Perkins Cancer Center, Baton Rouge, LA (United States); Brown, T; Dugas, J; Varnes, M [Mary Bird Perkins Cancer Center, Baton Rouge, LA (United States); Matthews, K [Louisiana State University, Baton Rouge, LA (United States)

2014-06-15

Purpose: To determine the biological effect from Auger electrons with 9% and 18% iododeoxyuridine (IUdR) incorporated into the DNA of rat 9L glioma cells at photon energies above and below the K-edge of iodine (33.2 keV). Methods: Rat 9L glioma cell survival versus dose curves with 0%, 9%, and 18% thymidine replacement with IUdR were measured using four irradiation energies (4 MV x-rays; monochromatic 35, 30, and 25 keV synchrotron photons). For each of 11 conditions (Energy, %IUdR) survival curves were fit to the data (826 cell cultures) using the linear-quadratic model. The ratio of doses resulting in 10% survival gave sensitization enhancement ratios (SER10) from which contributions due to linear-energy transfer (LET), radiosensitization (RS), and Auger effect (AE) were extracted. Results: At 35, 30, and 25 keV, SER10,LET values were 1.08±0.03, 1.22±0.02, and 1.37±0.02, respectively. At 4 MV SER10,RS values for 9% and 18% IUdR were 1.28±0.02 and 1.40±0.02, respectively. Assuming LET effects are independent of %IUdR and radiosensitization effects are independent of energy, SER10,AE values for 18% IUdR at 35, 30, and 25 keV were 1.35±0.05, 1.06±0.03, and 0.98±0.03, respectively; values for 9% IUdR at 35 and 25 keV were 1.01±0.04 and 0.82±0.02, respectively. Conclusion: For 18% IUdR the radiosensitization effect of 1.40 and the Auger effect of 1.35 at 35 keV are equally important to the combined effect of 1.90. No measureable Auger effect was observed for energies below the K-edge at 20 and 25 keV, as expected. The insignificant Auger effect at 9% IUdR was not expected. Additional data (40–70 keV) and radiobiological modeling are being acquired to better understand the energy dependence of Auger electron therapy with IUdR. Funding support in part by the National Science Foundation Graduate Research Fellowship Program and in part by Contract No. W81XWH-10-1-0005 awarded by the U.S. Army Research Acquisition Activity. This paper does not necessarily

QUIET-TIME SUPRATHERMAL (∼0.1–1.5 keV) ELECTRONS IN THE SOLAR WIND

Energy Technology Data Exchange (ETDEWEB)

Tao, Jiawei; Wang, Linghua; Zong, Qiugang; He, Jiansen; Tu, Chuanyi [School of Earth and Space Science, Peking University, Beijing 100871 (China); Li, Gang [Department of Physics and CSPAR, University of Alabama in Huntsville, Alabama 35899 (United States); Salem, Chadi S.; Bale, Stuart D. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Wimmer-Schweingruber, Robert F., E-mail: wanglhwang@gmail.com [Institute for Experimental and Applied Physics, University of Kiel, Leibnizstrasse 11, D-24118 Kiel (Germany)

2016-03-20

We present a statistical survey of the energy spectrum of solar wind suprathermal (∼0.1–1.5 keV) electrons measured by the WIND 3DP instrument at 1 AU during quiet times at the minimum and maximum of solar cycles 23 and 24. After separating (beaming) strahl electrons from (isotropic) halo electrons according to their different behaviors in the angular distribution, we fit the observed energy spectrum of both strahl and halo electrons at ∼0.1–1.5 keV to a Kappa distribution function with an index κ and effective temperature T{sub eff}. We also calculate the number density n and average energy E{sub avg} of strahl and halo electrons by integrating the electron measurements between ∼0.1 and 1.5 keV. We find a strong positive correlation between κ and T{sub eff} for both strahl and halo electrons, and a strong positive correlation between the strahl n and halo n, likely reflecting the nature of the generation of these suprathermal electrons. In both solar cycles, κ is larger at solar minimum than at solar maximum for both strahl and halo electrons. The halo κ is generally smaller than the strahl κ (except during the solar minimum of cycle 23). The strahl n is larger at solar maximum, but the halo n shows no difference between solar minimum and maximum. Both the strahl n and halo n have no clear association with the solar wind core population, but the density ratio between the strahl and halo roughly anti-correlates (correlates) with the solar wind density (velocity)

A study on the ranges of low energy ions in biological samples and its mechanism of biological effects

International Nuclear Information System (INIS)

Lu Ting; Xie Liqing; Li Junping; Xia Ji

1993-01-01

The seeds of wheat and bean are irradiated by iron ion beam with energy 100 keV. The RBS spectra of the samples are observed and the ranges and distributions of the iron ions in the wheat and bean are calculated theoretically by means of Monte Carlo method. The results of theory and experiment are compared and the mechanism of biological effects induced by ion is discussed

Electrostatic analysis of 750 keV DC accelerator

International Nuclear Information System (INIS)

Kumar, Abhay; Dwivedi, Jishnu; Jana, Arup Ratan

2011-01-01

The indigenously developed 750 keV DC accelerator working at RRCAT for the last 5 years uses SF 6 at 6 bar pressure as the insulating gas. The green house potential of this gas is about 22,000 times more than that of CO 2 gas. An electrostatic analysis of this accelerator was performed in order to probe the necessity of using this gas with a very elaborate gas handling system. The DC accelerator is approximated by a 2-D axisymmetric model in ANSYS and voltages were defined at the individual stages of the accelerating tube. The result of the study shows that the present design needs SF 6 gas and the pressure vessel dimensions need to be modified to operate the DC accelerator with environmentally friendly N 2 -CO 2 mixture. This paper presents the methodology of the analysis, discusses the DC accelerator finite element model and presents the results of the analysis. The paper also proposes changes in the DC accelerator design to run the accelerator with N 2 -CO 2 mixture. (author)

STOPOW/82 program for calculations of stopping powers and ranges for heavy ions in the energy range from 1 keV to 10 GeV/a.m.u

International Nuclear Information System (INIS)

Henniger, J.; Horlbeck, B.

1983-01-01

The program ST0POW/82 is created to calculate the stopping power and range of ions up to uranium in the energy range 1 keV/a. m. u. - 10 GeV/a. m. u. in any amorphous matter. The program is based on Ziegler's catalogue data and Ahlen's theoretical treatments. The Zsub(eff)sup(3) relativistic Bloch and Mott corrections and corrections on density effect are taken into account in the calculations. An opportunity of 9 different functions removal, derivative on the stopping power and range, for example, primary ionization and LET, and also of ion parameters, such as β, Zsub(eff)sup(2)/βsup(2) is foreseen. The program is written in FORTRAN language in version for the CDC-6500 computer. The program needs a minimized input also for compound targets. So it is useful for many problems in applied sciences and experimental physics