Ultra-fast electron capture by electrosterically-stabilized gold nanoparticles.

Science.gov (United States)

Ghandi, Khashayar; Findlater, Alexander D; Mahimwalla, Zahid; MacNeil, Connor S; Awoonor-Williams, Ernest; Zahariev, Federico; Gordon, Mark S

2015-07-21

Ultra-fast pre-solvated electron capture has been observed for aqueous solutions of room-temperature ionic liquid (RTIL) surface-stabilized gold nanoparticles (AuNPs; ∼9 nm). The extraordinarily large inverse temperature dependent rate constants (k(e)∼ 5 × 10(14) M(-1) s(-1)) measured for the capture of electrons in solution suggest electron capture by the AuNP surface that is on the timescale of, and therefore in competition with, electron solvation and electron-cation recombination reactions. The observed electron transfer rates challenge the conventional notion that radiation induced biological damage would be enhanced in the presence of AuNPs. On the contrary, AuNPs stabilized by non-covalently bonded ligands demonstrate the potential to quench radiation-induced electrons, indicating potential applications in fields ranging from radiation therapy to heterogeneous catalysis.

Simultaneous electron capture and excitation in ion-atom collisions

International Nuclear Information System (INIS)

Tanis, J.A.; Bernstein, E.M.; Graham, W.G.; Clark, M.; Shafroth, S.M.; Johnson, B.M.; Jones, K.; Meron, M.

1982-01-01

A review of recent efforts to observe simultaneous electron capture-and-K-shell excitation in ion-atom collisions is presented. This process which has been referred to as resonant-transfer-and-excitation (RTE), is qualitatively analogous to dielectronic recombination (inverse Auger transition) in free-electron-ion collisions, and, hence, is expected to be resonant. Experimentally, events having the correct signature for simultaneous capture-and-excitation are isolated by detecting projectile K x rays in coincidence with ions which capture a single electron. In a recent experiment involving 70-160 MeV S 13+ ions incident on Ar, a maximum was observed in the yield of projectile K x rays associated with electron capture. This maximum is attributed to simultaneous capture - and excitation. The position (120 MeV) and width (60 MeV) of the observed maximum are in good agreement with theoretical calculations. The data indicate that RTE is an important mechanism for inner-shell vacancy production in the energy range studied

The mass of the electron neutrino and electron capture in 163Ho

International Nuclear Information System (INIS)

Yasumi, S.; Rajasekaran, G.; Ando, M.; Ochiai, F.; Ikeda, H.; Ohta, T.; Stefan, P.M.; Maruyama, M.; Nashimoto, N.; Fujioka, M.; Ishii, K.; Shinozuka, T.; Sera, K.; Omori, T.; Izawa, G.; Yagi, M.; Masumoto, K.; Shima, K.

1983-01-01

To determine the mass of the electron neutrino, electron capture in 163 Ho was studied. From the intensity of M X-rays and the total number of 163 Ho atoms in a source, as determined by the PIXE method, the partial M-capture half life of 163 Ho was estimated to be (4.5 +- 1.5) x 10 4 yr. A relation between the Q-value of 163 Ho and the mass of the electron neutrino was obtained. (orig.)

Electron capture by highly charged ions from surfaces and gases

International Nuclear Information System (INIS)

Allen, F.

2008-01-01

In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar 17+ and Ar 18+ ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu -1 , charge-selected and then decelerated down to 5 eVu -1 for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar 17+ and Ar 18+ ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu -1 , charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar 16+ and Xe 44+ and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

Electron-capture process and ion mobility spectra in plasma chromatography

International Nuclear Information System (INIS)

Karasek, F.W.; Spangler, G.E.

1981-01-01

The basic principles of plasma chromatography are introduced and ion mobility relationships presented. The relationships of plasma chromatography to electron-capture detector mechanisms are discussed, including electron energy considerations and electron-capture reactions. A number of experimental studies by plasma chromatography are described. (C.F.)

State selective single-electron capture in O6++Nacollisions

NARCIS (Netherlands)

Knoop, S; Keim, M; Ludde, HJ; Kirchner, T; Morgenstern, [No Value; Hoekstra, R

2005-01-01

Single-electron capture in O6+ + Na collisions at 1-9 keV/amu collision energy has been studied both experimentally and theoretically. Partial cross sections for electron capture into n = 5, 6, 7, 8 and n >= 9 have been obtained from target recoil momenta measured by the technique of MOTRIMS and are

Electron capture detector based on a non-radioactive electron source: operating parameters vs. analytical performance

Directory of Open Access Journals (Sweden)

E. Bunert

2017-12-01

Full Text Available Gas chromatographs with electron capture detectors are widely used for the analysis of electron affine substances such as pesticides or chlorofluorocarbons. With detection limits in the low pptv range, electron capture detectors are the most sensitive detectors available for such compounds. Based on their operating principle, they require free electrons at atmospheric pressure, which are usually generated by a β− decay. However, the use of radioactive materials leads to regulatory restrictions regarding purchase, operation, and disposal. Here, we present a novel electron capture detector based on a non-radioactive electron source that shows similar detection limits compared to radioactive detectors but that is not subject to these limitations and offers further advantages such as adjustable electron densities and energies. In this work we show first experimental results using 1,1,2-trichloroethane and sevoflurane, and investigate the effect of several operating parameters on the analytical performance of this new non-radioactive electron capture detector (ECD.

Electron capture by highly charged ions from surfaces and gases

Energy Technology Data Exchange (ETDEWEB)

Allen, F.

2008-01-11

In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar{sup 17+} and Ar{sup 18+} ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu{sup -1}, charge-selected and then decelerated down to 5 eVu{sup -1} for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar{sup 17+} and Ar{sup 18+} ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu{sup -1}, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar{sup 16+} and Xe{sup 44+} and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

Electronic case report forms and electronic data capture within clinical trials and pharmacoepidemiology.

Science.gov (United States)

Rorie, David A; Flynn, Robert W V; Grieve, Kerr; Doney, Alexander; Mackenzie, Isla; MacDonald, Thomas M; Rogers, Amy

2017-09-01

Researchers in clinical and pharmacoepidemiology fields have adopted information technology (IT) and electronic data capture, but these remain underused despite the benefits. This review discusses electronic case report forms and electronic data capture, specifically within pharmacoepidemiology and clinical research. The review used PubMed and the Institute of Electrical and Electronic Engineers library. Search terms used were agreed by the authors and documented. PubMed is medical and health based, whereas Institute of Electrical and Electronic Engineers is technology based. The review focuses on electronic case report forms and electronic data capture, but briefly considers other relevant topics; consent, ethics and security. There were 1126 papers found using the search terms. Manual filtering and reviewing of abstracts further condensed this number to 136 relevant manuscripts. The papers were further categorized: 17 contained study data; 40 observational data; 27 anecdotal data; 47 covering methodology or design of systems; one case study; one literature review; two feasibility studies; and one cost analysis. Electronic case report forms, electronic data capture and IT in general are viewed with enthusiasm and are seen as a cost-effective means of improving research efficiency, educating participants and improving trial recruitment, provided concerns about how data will be protected from misuse can be addressed. Clear operational guidelines and best practises are key for healthcare providers, and researchers adopting IT, and further work is needed on improving integration of new technologies with current systems. A robust method of evaluation for technical innovation is required. © 2017 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.

Single electron capture in N^+ -(Ne, Kr, Xe) collisions

Science.gov (United States)

Reyes, Pedro G.; Castillo, Fermin; Martinez, Horacio

2001-05-01

Total cross sections for single electron capture of N^+ ions impinging on Ne, Kr and Xe were measured in the energy range of 1.5 to 5.0 keV. The electron capture cross sections for all the targets studied are found to be in excellent agreement with previous data in the low-energy range. The present data together with previous measurements give a general shape of the whole curve of single electron capture cross sections for the N^+ - Ne system. For the cases of N^+ - (Kr, Xe) systems, semiempirical calculation using the two-state approximation are in very good agreement with present cross sections data. Research supported by DGAPA IN-100392 and CONACyT 32175-E

Super-AGB Stars and their Role as Electron Capture Supernova Progenitors

Science.gov (United States)

Doherty, Carolyn L.; Gil-Pons, Pilar; Siess, Lionel; Lattanzio, John C.

2017-11-01

We review the lives, deaths and nucleosynthetic signatures of intermediate-mass stars in the range ≈6-12 M⊙, which form super-AGB stars near the end of their lives. The critical mass boundaries both between different types of massive white dwarfs (CO, CO-Ne, ONe), and between white dwarfs and supernovae, are examined along with the relative fraction of super-AGB stars that end life either as an ONe white dwarf or as a neutron star (or an ONeFe white dwarf), after undergoing an electron capture supernova event. The contribution of the other potential single-star channel to electron-capture supernovae, that of the failed massive stars, is also discussed. The factors that influence these different final fates and mass limits, such as composition, rotation, the efficiency of convection, the nuclear reaction rates, mass-loss rates, and third dredge-up efficiency, are described. We stress the importance of the binary evolution channels for producing electron-capture supernovae. Recent nucleosynthesis calculations and elemental yield results are discussed and a new set of s-process heavy element yields is presented. The contribution of super-AGB star nucleosynthesis is assessed within a Galactic perspective, and the (super-)AGB scenario is considered in the context of the multiple stellar populations seen in globular clusters. A brief summary of recent works on dust production is included. Last, we conclude with a discussion of the observational constraints and potential future advances for study into these stars on the low mass/high mass star boundary.

Evidence for correlated double-electron capture in slow O6+ + He collisions

International Nuclear Information System (INIS)

Phaneuf, R.A.; Meyer, F.W.; Havener, C.C.; Stolterfoht, N.; Swenson, J.K.; Shafroth, S.M.

1987-01-01

Double electron capture by few-electron multicharged ions during slow collisions with He may result in Auger-decaying product states of the projectile, provided the initial projectile charge exceeds +4. These autoionizing states can be characterized by either (nearly) equivalent electron configurations, in which the two captured electrons occupy essentially the same or adjacent shells, or by non-equivalent configurations, in which one of the electrons is in a Rydberg state. Using the method of zero-degree Auger spectroscopy, the authors have verified population of both types of autoionizing states by double electron capture during slow collisions of O 6+ with He: for these systems, both LMM Auger electrons, attributed to the (nearly) equivalent electron configuration (1s 2 ) 3iota3iota' or (1s 2 )3iota4iota', and L 1 L 23 M-Coster Kronig electrons, attributed to the non-equivalent electron configurations (1s 2 )2pniota, were observed. Comparison of the LMM Auger electron and Coster Kronig electron production cross sections suggests that the correlated double capture process is of comparable importance to the sequential single capture mechanism

Electron capture in asymmetric collisions

International Nuclear Information System (INIS)

Graviele, M.S.; Miraglia, J.E.

1988-01-01

It is calculated the electronic capture of K shell by protons using the on-shell impulsive wave functions, exact and eikonal, in the initial and final channels respectively. Both wave functions are normalized and have the correct asyntotic conditions. A good agreement to the experimental data is found. (A.C.A.S.) [pt

Electron capture to autoionizing states of multiply charged ions

International Nuclear Information System (INIS)

Mack, E.M.

1987-01-01

The present thesis investigates electron capture reactions resulting from slow collisions (V q+ ) and neutral gas targets (B). The energy spectra of the emitted electrons are measured; detection angle is 50 0 . Mainly, autoionizing double capture resulting from collisions with two-electron targets (He, H 2 ) is studied; then, the emitted electrons stem from doubly excited projectile states. The projectiles used are bare C 6+ , the H-like and He-like ions of C, N and O, He-like Ne 8+ and Ne-like Ar 8+ . Excited metastable projectiles used are C 5+ (2s), He-like projectiles A q+ (1s2s 3 S) and Ar 8+ (...2p 5 3s). Comparison is made with the predictions of a recently proposed extended classical barrier model, that was developed in connection with the work. This model assumes sequential capture of the electrons ('two-step' process); it predicts the realized binding enegies of the captured electrons - which may be directly determined from the autoionization spectra using only the projectile charge, the ionization potentials of the target and the collision velocity as parameters. No adjustable parameter enters into the calculations. The term energies and decay modes of the highly excited product ions themselves are studied. Generally, the autoionizing decay of these states is found to proceed preferentially to the directly adjacent lower singly excited state. Experimental evidence is presented, that triply excited states decay by successive emission of two electrons, whenever this is energetically possible. Finally, the L-MM decay in few-electron systems is considered. 314 refs.; 96 figs.; 29 tabs

Alpha-particle and electron capture decay of 209Po

International Nuclear Information System (INIS)

Schima, F.J.; Colle, R.

1996-01-01

Gamma-ray and Kα X-ray emissions have been measured from a very pure 209 Po source containing less than 0.13% 208 Po activity and no detectable 210 Po (≤2 x 10 -4 %). The alpha-particle emission rate for this source has previously been determined. Data are presented that confirm alpha decay to the 205 Pb excited level at 262.8 keV, with an alpha-particle emission probability (±standard uncertainty) of 0.00559±0.00008. The ratio of K-shell electron capture to total electron capture for the second forbidden unique electron capture decay to the 896.6 keV level in 209 Bi was determined to be 0.594±0.018. The electron capture decay fraction was found to be 0.00454±0.00007, while the probabilities per decay for the 896.6, 262.8, and 260.5 keV gamma rays and the Bi Kα and Pb Kα X-rays were measured as 0.00445±0.00007, 0.00085±0.00002, 0.00254±0.00003, 0.00202±0.00005, and 0.00136±0.00005, respectively. (orig.)

Supernovae and nuclear structure: Electron capture and the nuclear incompressibility

International Nuclear Information System (INIS)

Cooperstein, J.

1985-01-01

The author considers the effects of electron capture and the high density equation of state on supernovae. Electron captures on nuclei with 60 s it is helpful for supernovae to have a soft equation of state. Present knowledge of the nuclear matter parameters is considered and implications for supernovae are drawn. (orig.)

Correlated double electron capture in slow, highly charged ion-atom collisions

International Nuclear Information System (INIS)

Stolterfoht, N.; Havener, C.C.; Phaneuf, R.A.; Swenson, J.K.; Shafroth, S.M.; Meyer, F.W.

1986-01-01

Recent measurements of autoionization electrons produced in slow, highly charged ion-atom collisions are reviewed. Mechanisms for double electron capture into equivalent and nonequivalent configurations are analyzed by comparing the probabilities for the creation of L 1 L 23 X Coster Kronig electrons and L-Auger electrons. It is shown that the production of the Coster-Kronig electrons is due to electron correlation effects whose analysis leads beyond the independent-particle model. The importance of correlation effects on different capture mechanisms is discussed. 28 refs., 6 figs

Calculations on Electron Capture in Low Energy Ion-Molecule Collisions

Energy Technology Data Exchange (ETDEWEB)

Stancil, P.C. [Oak Ridge National Lab., TN (United States); Zygelman, B. [W.M. Keck Lab. for Computational Physics, Univ. of Nevada, Las Vegas, NV (United States); Kirby, K. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

1997-12-31

Recent progress on the application of a quantal, molecular-orbital, close-coupling approach to the calculation of electron capture in collisions of multiply charged ions with molecules is discussed. Preliminary results for single electron capture by N{sup 2+} with H{sub 2} are presented. Electron capture by multiply charged ions colliding with H{sub 2} is an important process in laboratory and astrophysical plasmas. It provides a recombination mechanism for multiply charged ions in x-ray ionized astronomical environments which may have sparse electron and atomic hydrogen abundances. In the divertor region of a tokamak fusion device, charge exchange of impurity ions with H{sub 2} plays a role in the ionization balance and the production of radiative energy loss leading to cooling, X-ray and ultraviolet auroral emission from Jupiter is believed to be due to charge exchange of O and S ions with H{sub 2} in the Jovian atmosphere. Solar wind ions interacting with cometary molecules may have produced the x-rays observed from Comet Hyakutake. In order to model and understand the behavior of these environments, it is necessary to obtain total, electronic state-selective (ESS), and vibrational (or rotational) state-selective (VSS) capture cross sections for collision energies as low as 10 meV/amu to as high as 100 keV/amu in some instances. Fortunately, charge transfer with molecular targets has received considerable experimental attention. Numerous measurements have been made with flow tubes, ion traps, and ion beams. Flow tube and ion trap studies generally provide information on rate coefficients for temperatures between 800 K and 20,000 K. In this article, we report on the progress of our group in implementing a quantum-mechanical Molecular Orbital Close Coupling (MOCC) approach to the study of electron capture by multiply charged ions in collisions with molecules. We illustrate this with a preliminary investigation of Single Electron Capture (SEC) by N{sup 2+} with H

Electronic data capture and DICOM data management in multi-center clinical trials

Science.gov (United States)

Haak, Daniel; Page, Charles-E.; Deserno, Thomas M.

2016-03-01

Providing eligibility, efficacy and security evaluation by quantitative and qualitative disease findings, medical imaging has become increasingly important in clinical trials. Here, subject's data is today captured in electronic case reports forms (eCRFs), which are offered by electronic data capture (EDC) systems. However, integration of subject's medical image data into eCRFs is insufficiently supported. Neither integration of subject's digital imaging and communications in medicine (DICOM) data, nor communication with picture archiving and communication systems (PACS), is possible. This aggravates the workflow of the study personnel, in special regarding studies with distributed data capture in multiple sites. Hence, in this work, a system architecture is presented, which connects an EDC system, a PACS and a DICOM viewer via the web access to DICOM objects (WADO) protocol. The architecture is implemented using the open source tools OpenClinica, DCM4CHEE and Weasis. The eCRF forms the primary endpoint for the study personnel, where subject's image data is stored and retrieved. Background communication with the PACS is completely hidden for the users. Data privacy and consistency is ensured by automatic de-identification and re-labelling of DICOM data with context information (e.g. study and subject identifiers), respectively. The system is exemplarily demonstrated in a clinical trial, where computer tomography (CT) data is de-centrally captured from the subjects and centrally read by a chief radiologists to decide on inclusion of the subjects in the trial. Errors, latency and costs in the EDC workflow are reduced, while, a research database is implicitly built up in the background.

Correlated double electron capture in slow, highly charged ion-atom collisions

Energy Technology Data Exchange (ETDEWEB)

Stolterfoht, N.; Havener, C.C.; Phaneuf, R.A.; Swenson, J.K.; Shafroth, S.M.; Meyer, F.W.

1986-01-01

Recent measurements of autoionization electrons produced in slow, highly charged ion-atom collisions are reviewed. Mechanisms for double electron capture into equivalent and nonequivalent configurations are analyzed by comparing the probabilities for the creation of L/sub 1/L/sub 23/X Coster Kronig electrons and L-Auger electrons. It is shown that the production of the Coster-Kronig electrons is due to electron correlation effects whose analysis leads beyond the independent-particle model. The importance of correlation effects on different capture mechanisms is discussed. 28 refs., 6 figs.

Experimental studies of electron capture

International Nuclear Information System (INIS)

Pedersen, E.H.

1983-01-01

This thesis discusses the main results of recent experimental studies of electron capture in asymmetric collisions. Most of the results have been published, but the thesis also contains yet unpublished data, or data presented only in unrefereed conference proceedings. The thesis aims at giving a coherent discussion of the understanding of the experimental results, based first on simple qualitative considerations and subsequently on quantitative comparisons with the best theoretical calculations currently available. (Auth.)

Electron Capture Cross Sections for Stellar Nucleosynthesis

Directory of Open Access Journals (Sweden)

P. G. Giannaka

2015-01-01

Full Text Available In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasiparticle random-phase approximation (pn-QRPA and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the abovementioned e--capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the 66Zn isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.

Introductory remarks on electron capture by multicharged ions

International Nuclear Information System (INIS)

Crandall, D.H.

1979-01-01

An overview is presented of applications of multicharged-ion electron capture and, through the qualitative assessment of availability of information, the general status of current understanding of such capture. A chart is given on which the various ion collision processes are related to other pertinent fields of physical research notably fusion, astrophysics, the solar corona, and lasers. The production and transport of ions is also noted. The symposium considers collision velocities less than 4 x 10 8 cm/s, where the capture cross sections are largest and where most of the available results are quite recent

State-selective electron capture

International Nuclear Information System (INIS)

Dunford, R.W.; Liu, C.J.; Berry, H.G.; Pardo, R.C.; Raphaelian, M.L.A.

1988-01-01

We report results from a new atomic physics program using the Argonne PII ECR ion source which is being built as part of the upgrade of the Argonne Tandem-Linear Accelerator (ATLAS). Our initial experiments have been aimed at studying state-selective electron capture in ion-atom collisions using the technique of Photon Emission Spectroscopy. We are extending existing cross section measurements at low energy ( 6+ and O 7+ on He and H 2 targets in the energy range from 1-105 keV/amu. We also present uv spectra obtained in collisions of O 6+ , O 5+ and N 5+ on a sodium target. 4 refs., 2 figs., 1 tab

Electron capture in pseudo-two-electron systems: Ar8++He

International Nuclear Information System (INIS)

Kimura, M.; Olson, R.E.

1985-01-01

Molecular-structure calculations using the pseudopotential method have been performed on the (ArHe) 8+ system. The cross section for single-electron capture in Ar 8+ +He collisions was calculated for energies from 20 eV to 10 keV/amu. The perturbed-stationary-state method [M. Kimura, H. Sato, and R. E. Olson, Phys. Rev. A 28, 2085 (1983)], modified to include electron translation factors appropriate to two-electron systems, was used. The total cross section is relatively energy independent with a value of approximately 2.5 x 10 -15 cm 2 . The n = 4 level of Ar 7+ is found to be preferentially populated, with the 4f level being dominant

Atomic and nuclear parameters of single electron capture decaying nuclides

International Nuclear Information System (INIS)

Grau, A.

1981-01-01

Atomic and nuclear parameters of the following nuclides which decay by electron capture have been calculated: 37 A r, 41 C a, 49 V , 53 M n, 55 F e,59 N i, 68Ge,82 S r, 97 T c, 118 T e, 131 C s, 137 L a, 140 N d, 157 T b, 165 E r, 193 p t, 194 H g, and 205 P h The evaluation rules are included in the first part of the paper. The values and the associated uncertainties of the following parameters have been tabulated: decay energy, electron capture probabilities, fluorescence yield, electron emission and X-ray emission. (Author) 27 refs

Dipole-Guided Electron Capture Causes Abnormal Dissociations of Phosphorylated Pentapeptides

DEFF Research Database (Denmark)

Moss, Christopher L.; Chung, Thomas W.; Wyer, Jean

2011-01-01

energies and fluoranthene anion radicals in an ion trap resulted in the loss of a hydrogen atom, ammonia, and backbone cleavages forming complete series of sequence z ions. Elimination of phosphoric acid was negligible. In contrast, capture of lowenergy electrons by doubly charged ions in a Penning ion...... mapping of the potential energy surface provided structures for the precursor phosphopeptide dications. Electron attachment produces a multitude of low lying electronic states in charge-reduced ions that determine their reactivity in backbone dissociations and H- atom loss. The predominant loss of H atoms......Abstract Electron transfer and capture mass spectra of a series of doubly charged ions that were phosphorylated pentapeptides of a tryptic type (pS,A,A,A,R) showed conspicuous differences in dissociations of charge-reduced ions. Electron transfer from both gaseous cesium atoms at 100 keV kinetic...

Electronic radiative capture in solid targets

International Nuclear Information System (INIS)

Pregliasco, R.; Nemirovsky, I.; Suarez, S.

1988-01-01

X-ray spectra originating from electron radiative capture from aluminium target to K shell on F 9+ and F 8+ beams with 115MeV are studied. Using an electrostatic analyzer, it was obtained the charge fractions Fi to aluminiun thicknesses of 39 and 58 micrograms/cm 2 . These thicknesses are determined by the stopping power of alpha particles. (A.C.A.S.) [pt

Resonant electron capture by aspartame and aspartic acid molecules.

Science.gov (United States)

Muftakhov, M V; Shchukin, P V

2016-12-30

The processes for dissociative electron capture are the key mechanisms for decomposition of biomolecules, proteins in particular, under interaction with low-energy electrons. Molecules of aspartic acid and aspartame, i.e. modified dipeptides, were studied herein to define the impact of the side functional groups on peptide chain decomposition in resonant electron-molecular reactions. The processes of formation and decomposition of negative ions of both aspartame and aspartic acid were studied by mass spectrometry of negative ions under resonant electron capture. The obtained mass spectra were interpreted under thermochemical analysis by quantum chemical calculations. Main channels of negative molecular ions fragmentation were found and characteristic fragment ions were identified. The СООН fragment of the side chain in aspartic acid is shown to play a key role like the carboxyl group in amino acids and aliphatic oligopeptides. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Electron capture Auger aftereffect of ammine cobalt complex

International Nuclear Information System (INIS)

Harada, Masayuki; Sano, Hirotoshi

1976-01-01

The study of ammine cobalt complex by luminescent Moessbauer spectrometry method was performed. The method was compared with hot atom chemistry method. The electron states in atoms are changed by the aftereffect on Auger emission following the electron capture process. The state of oxidation of disintegration products is usually higher than that of parent nuclei. However, sometimes, lower oxidation is seen in Fe-57, the daughter nuclei of Co-57. This phenomenon may be due to radiation chemistry process, and this effect can be observed by the luminescent Moessbauer spectrometry method. However, the range of the effect can not be seen by the Moessbauer method. Estimation showed that the Auger electrons stay within the surrounding area of the disintegration atom, and the effect does not reach to distant places. The yield of Fe-57 in the electron capture process of Co-57 in cobalt complex, the G-value, and the hot atom chemical yield were obtained. It is concluded that the aftereffect of the Auger process is the localized radiation chemistry effect. Good correlation was seen between the present method and the hot atom chemistry method. (Kato, T.)

Optimising the application of multiple-capture traps for invasive species management using spatial simulation.

Science.gov (United States)

Warburton, Bruce; Gormley, Andrew M

2015-01-01

Internationally, invasive vertebrate species pose a significant threat to biodiversity, agricultural production and human health. To manage these species a wide range of tools, including traps, are used. In New Zealand, brushtail possums (Trichosurus vulpecula), stoats (Mustela ermine), and ship rats (Rattus rattus) are invasive and there is an ongoing demand for cost-effective non-toxic methods for controlling these pests. Recently, traps with multiple-capture capability have been developed which, because they do not require regular operator-checking, are purported to be more cost-effective than traditional single-capture traps. However, when pest populations are being maintained at low densities (as is typical of orchestrated pest management programmes) it remains uncertain if it is more cost-effective to use fewer multiple-capture traps or more single-capture traps. To address this uncertainty, we used an individual-based spatially explicit modelling approach to determine the likely maximum animal-captures per trap, given stated pest densities and defined times traps are left between checks. In the simulation, single- or multiple-capture traps were spaced according to best practice pest-control guidelines. For possums with maintenance densities set at the lowest level (i.e. 0.5/ha), 98% of all simulated possums were captured with only a single capacity trap set at each site. When possum density was increased to moderate levels of 3/ha, having a capacity of three captures per trap caught 97% of all simulated possums. Results were similar for stoats, although only two potential captures per site were sufficient to capture 99% of simulated stoats. For rats, which were simulated at their typically higher densities, even a six-capture capacity per trap site only resulted in 80% kill. Depending on target species, prevailing density and extent of immigration, the most cost-effective strategy for pest control in New Zealand might be to deploy several single-capture

Single-electron capture in He2+-D2 collisions

International Nuclear Information System (INIS)

Bordenave-Montesquieu, D.; Dagnac, R.

1994-01-01

Doubly differential cross sections of single-electron capture were measured for He 2+ impinging on a molecular deuterium target. The investigated collision energies are 4, 6 and 8 keV and the scattering angles range from 10' to 2 o 30' (laboratory frame). The exothermic capture leading to He + (1s) + D 2 +* was found to be the most important process at low energies and angles, whereas the endothermic channels leading to dissociative capture become the main processes at high scattering angles, i.e. at small impact parameters. (author)

The electron capture in 163Ho experiment - ECHo

Science.gov (United States)

Gastaldo, L.; Blaum, K.; Chrysalidis, K.; Day Goodacre, T.; Domula, A.; Door, M.; Dorrer, H.; Düllmann, Ch. E.; Eberhardt, K.; Eliseev, S.; Enss, C.; Faessler, A.; Filianin, P.; Fleischmann, A.; Fonnesu, D.; Gamer, L.; Haas, R.; Hassel, C.; Hengstler, D.; Jochum, J.; Johnston, K.; Kebschull, U.; Kempf, S.; Kieck, T.; Köster, U.; Lahiri, S.; Maiti, M.; Mantegazzini, F.; Marsh, B.; Neroutsos, P.; Novikov, Yu. N.; Ranitzsch, P. C. O.; Rothe, S.; Rischka, A.; Saenz, A.; Sander, O.; Schneider, F.; Scholl, S.; Schüssler, R. X.; Schweiger, Ch.; Simkovic, F.; Stora, T.; Szücs, Z.; Türler, A.; Veinhard, M.; Weber, M.; Wegner, M.; Wendt, K.; Zuber, K.

2017-06-01

Neutrinos, and in particular their tiny but non-vanishing masses, can be considered one of the doors towards physics beyond the Standard Model. Precision measurements of the kinematics of weak interactions, in particular of the 3H β-decay and the 163Ho electron capture (EC), represent the only model independent approach to determine the absolute scale of neutrino masses. The electron capture in 163Ho experiment, ECHo, is designed to reach sub-eV sensitivity on the electron neutrino mass by means of the analysis of the calorimetrically measured electron capture spectrum of the nuclide 163Ho. The maximum energy available for this decay, about 2.8 keV, constrains the type of detectors that can be used. Arrays of low temperature metallic magnetic calorimeters (MMCs) are being developed to measure the 163Ho EC spectrum with energy resolution below 3 eV FWHM and with a time resolution below 1 μs. To achieve the sub-eV sensitivity on the electron neutrino mass, together with the detector optimization, the availability of large ultra-pure 163Ho samples, the identification and suppression of background sources as well as the precise parametrization of the 163Ho EC spectrum are of utmost importance. The high-energy resolution 163Ho spectra measured with the first MMC prototypes with ion-implanted 163Ho set the basis for the ECHo experiment. We describe the conceptual design of ECHo and motivate the strategies we have adopted to carry on the present medium scale experiment, ECHo-1K. In this experiment, the use of 1 kBq 163Ho will allow to reach a neutrino mass sensitivity below 10 eV/ c 2. We then discuss how the results being achieved in ECHo-1k will guide the design of the next stage of the ECHo experiment, ECHo-1M, where a source of the order of 1 MBq 163Ho embedded in large MMCs arrays will allow to reach sub-eV sensitivity on the electron neutrino mass.

Orbital electron capture measurements with an internal-source spectrometer

International Nuclear Information System (INIS)

Gerner, C.P.

1978-01-01

Electron-capture measurements have been performed on 131 Ba and on 106 Agsup(m). For 131 Ba the L/K-and M/L-capture rations of the allowed decay have been measured to the 1048 keV level in 131 Cs. The Qsub(EC) value, the exchange- and overlap-correction factors Xsup(L/K) and Xsup(M/L) and the reduced capture ratios have been determined. For 106 Agsup(m) the L/K-capture ratio of the allowed decay has been measured to the 2757 keV level in 106 Pd. The Q value, the exchange- and overlap-correction factor Xsup(L/K) and the reduced L/K- capture ratio have been derived. The measurements indicate that agreement between experimentally determined capture ratios and exchange-corrected theoretical predictions is fairly good, both for allowed and for first-forbidden non-unique transitions. (Auth./C.F.)

Theory of nuclear excitation by electron capture for heavy ions

International Nuclear Information System (INIS)

Palffy, Adriana; Scheid, Werner; Harman, Zoltan

2006-01-01

We investigate the resonant process of nuclear excitation by electron capture (NEEC), in which a continuum electron is captured into a bound state of an ion with the simultaneous excitation of the nucleus. In order to derive the cross section a Feshbach projection operator formalism is introduced. Nuclear states and transitions are described by a nuclear collective model and making use of experimental data. Transition rates and total cross sections for NEEC followed by the radiative decay of the excited nucleus are calculated for various heavy-ion collision systems

Responses and mechanisms of positive electron affinity molecules in the N2 mode of the thermionic ionization detector and the electron-capture detector

International Nuclear Information System (INIS)

Jones, C.S.

1989-01-01

Very little knowledge has been acquired in the past on the mechanistic pathway by which molecules respond in the N 2 mode of the thermionic ionization detector. An attempt is made here to elucidate the response mechanism of the detector. The basic response mechanisms are known for the electron capture detector, and an attempt is made to identify the certain mechanism by which selected molecules respond. The resonance electron capture rate constant has been believed to be temperature independent, and investigations of the temperature dependence of electron capture responses are presented. Mechanisms for the N 2 mode of the thermionic ionization detector have been proposed by examining the detector response to positive electron affinity molecules and by measurement of the ions produced by the detector. Electron capture mechanisms for selected molecules have been proposed by examining their temperature dependent responses in the electron capture detector and negative ion mass spectra of the samples. In studies of the resonance electron capture rate constant, the relative responses of selected positive electron affinity molecules and their temperature dependent responses were investigated. Positive electron affinity did not guarantee large responses in the N 2 mode thermionic ionization detector. High mass ions were measured following ionization of samples in the detector. Responses in the electron capture detector varied with temperature and electron affinity

Impact of electron-captures on nuclei near N = 50 on core-collapse supernovae

Science.gov (United States)

Titus, R.; Sullivan, C.; Zegers, R. G. T.; Brown, B. A.; Gao, B.

2018-01-01

The sensitivity of the late stages of stellar core collapse to electron-capture rates on nuclei is investigated, with a focus on electron-capture rates on 74 nuclei with neutron number close to 50, just above doubly magic 78Ni. It is demonstrated that variations in key characteristics of the evolution, such as the lepton fraction, electron fraction, entropy, stellar density, and in-fall velocity are about 50% due to uncertainties in the electron-capture rates on nuclei in this region, although thousands of nuclei are included in the simulations. The present electron-capture rate estimates used for the nuclei in this high-sensitivity region of the chart of isotopes are primarily based on a simple approximation, and it is shown that the estimated rates are likely too high, by an order of magnitude or more. Electron-capture rates based on Gamow-Teller strength distributions calculated in microscopic theoretical models will be required to obtain better estimates. Gamow-Teller distributions extracted from charge-exchange experiments performed at intermediate energies serve to guide the development and benchmark the models. A previously compiled weak-rate library that is used in the astrophysical simulations was updated as part of the work presented here, by adding additional rate tables for nuclei near stability for mass numbers between 60 and 110.

Interatomic Coulombic electron capture in atomic, molecular, and quantum dot systems

Directory of Open Access Journals (Sweden)

Bande Annika

2015-01-01

Full Text Available The interatomic Coulombic electron capture (ICEC process has recently been predicted theoretically for clusters of atoms and molecules. For an atom A capturing an electron e(ε it competes with the well known photorecombination, because in an environment of neutral or anionic neighboring atoms B, A can transfer its excess energy in the ultrafast ICEC process to B which is then ionized. The cross section for e(ε + A + B → A− + B+ + e(ε′ has been obtained in an asymptotic approximation based on scattering theory for several clusters [1,2]. It was found that ICEC starts dominating the PR for distances among participating species of nanometers and lower. Therefore, we believe that the ICEC process might be of importance in the atmosphere, in biological systems, plasmas, or in nanostructured materials. As an example for the latter, ICEC has been investigated by means of electron dynamics in a model potential for semiconductor double quantum dots (QDs [3]. In the simplest case one QD captures an electron while the outgoing electron is emitted from the other. The reaction probability for this process was found to be relatively large.

Κ-electron capture probability in 167Tm

International Nuclear Information System (INIS)

Sree Krishna Murty, G.; Chandrasekhar Rao, M.V.S.; Radha Krishna, K.; Bhuloka Reddy, S.; Satyanarayana, G.; Ramana Rao, P.V.; Sastry, D.L.

1990-01-01

The Κ-electron capture probability in the decay of 167 Tm for the first-forbidden transition 1/2 + →3/2 - was measured using the sum-coincidence method and employing a hyper-pure Ge system. The P Κ value is found to be 0.835±0.029, in agreement with the theoretical value of 0.829. (author)

Ionization and single electron capture in collision of highly charged Ar16+ ions with helium

International Nuclear Information System (INIS)

Wang Fei; Gou Bingcong

2008-01-01

This paper uses the two-centre atomic orbital close-coupling method to study the ionization and the single electron capture in collision of highly charged Ar 16+ ions with He atoms in the velocity range of 1.2–1.9 a.u. The relative importance of single ionization (SI) to single capture (SC) is explored. The comparison between the calculation and experimental data shows that the SI/SC cross section ratios from this work are in good agreement with experimental data. The total single electron ionization cross sections and the total single electron capture cross sections are also given for this collision. The investigation of the partial electron capture cross section shows a general tendency of capture to larger n and l with increasing velocity from 1.2 to 1.9 a.u

Population of Rydberg states by electron capture in fast-ion--atom collisions

International Nuclear Information System (INIS)

Burgdoerfer, J.; Dube, L.J.

1985-01-01

The l,m-substate distribution in low-lying Rydberg manifolds (nroughly-equal10) following electron capture H + +H(1s)→H(n)+H + is calculated at high velocities (v>1 a.u.) in the continuum-distorted-wave (CDW) approximation. The standard CDW approximation is modified to account for final-state Stark mixing of the Rydberg manifold in the exit channel using the post-collision-interaction model. The influence of multiple-scattering contributions is analyzed and comparison is made with sigma/sub l/m predicted by the Born approximation. We find that the double-scattering contribution, closely connected with the classical Thomas process, becomes visible in the CDW approximation at surprisingly low nonasymptotic velocities

Electron Capture in Proton Collisions with CO.

Science.gov (United States)

Stancil, P. C.; Schultz, D. R.; Kimura, M.; Gu, J.-P.; Hirsch, G.; Buenker, R. J.; Li, Y.

1999-10-01

Electron capture by protons following collisions with carbon monoxide is studied with a variety of theoretical approaches including quantal and semiclassical molecular-orbital close-coupling (MOCC) and classical trajectory Monte Carlo (CTMC) techniques. The MOCC treatments utilize potential surfaces and couplings computed for a range of H^+-CO orientation angles and C-O separations. Results including integral, differential, electronic state-selective, and vibrational state-selective cross sections will be presented for low- to intermediate-energies. Comparison with experiment will be made where possible and the relevance of the reaction in astrophysics and atmospheric physics will be discussed.

Asymptotic coulombic conditions in the electron capture process

International Nuclear Information System (INIS)

Corchs, S.E.; Maidagan, J.M.; Rivarola, R.D.

1990-01-01

Several first order perturbative approximations of the transition amplitude for electronic capture are studied. Different models in which the long range Coulomb potential is represented by different internuclear dependent phases, in the initial and final wave functions, are analysed and compared. (Author). 8 refs., 2 figs

Recent investigations on electronic capture in atomic collisions

International Nuclear Information System (INIS)

Rivarola, R.D.

1988-01-01

In this work, electron capture processes in ion-atom collisions at various impact energy ranges are dicussed: i) intermediate non-relativistic energy; ii) high energy; iii) high relativistic energy. Much attention is given to the development and use of distorted wave models. (A.C.A.S.) [pt

Search for new candidates for the neutrino-oriented mass determination by electron-capture

CERN Multimedia

Herfurth, F; Boehm, C; Blaum, K; Beck, D

2008-01-01

This proposal is part of an extended program dedicated to the neutrino-mass determination in the electron-capture sector, which aims at ultra-precise mass measurements by Penning traps in combination with cryogenic micro-calorimetry for atomic de-excitation measurements. Here, precise mass measurements with ISOLTRAP are proposed for the orbital electron-capture nuclides $^{194}$Hg and $^{202}$Pb, as well as their daughters, with the goal to determine accurately their Q-values. These values are expected to be the smallest ones among a great variety of known electron-capture precursors. Therefore, these nuclides are strong candidates for an improved electron-neutrino mass determination. We ask for 8 shifts of on-line beam at ISOLDE for mass measurements of $^{194}$Hg, $^{194}$ Au, $^{202}$Pb, and $^{202}$Tl at ISOLTRAP.

Double electron capture by protons in collisions with H2

International Nuclear Information System (INIS)

Salazar-Zepeda, M.H.; Gleason, Cristian; Gonzalez, Eduardo; Gonzalez-Magana, O.; Hinojosa, Guillermo

2010-01-01

Double electron capture of protons in collisions with molecular hydrogen in the energy range 1.5-10 keV was studied by measuring the resulting H - velocity distributions. In this paper, a technique that provides experimental evidence about double capture mechanisms is proposed. In addition, cross-sections for this process were measured in the energy range of 1-5 keV.

Electron capture by highly charged low-velocity ions

International Nuclear Information System (INIS)

Cocke, C.L.; Dubois, R.; Justiniano, E.; Gray, T.J.; Can, C.

1982-01-01

This paper describes the use of a fast heavy ion beam to produce, by bombardment of gaseous targets, highly-charged low-velocity recoil ions, and the use of these secondary ions in turn as projectiles in studies of electron capture and ionization in low-energy collision systems. The interest in collisions involving low-energy highly-charged projectiles comes both from the somewhat simplifying aspects of the physics which attend the long-range capture and from applications to fusion plasmas, astrophysics and more speculative technology such as the production of X-ray lasers. The ions of interest in such applications should have both electronic excitation and center-of-mass energies in the keV range and cannot be produced by simply stripping fast heavy ion beams. Several novel types of ion source have been developed to produce low-energy highly-charged ions, of which the secondary ion recoil source discussed in this paper is one. (Auth.)

Electron capture and energy-gain spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Taulbjerg, K.

1989-01-01

The applicability of translation energy spectroscopy as a tool to determine individual reaction cross sections in atomic collisions is analyzed with special emphasis on the electron capture process in highly charged ion collisions. A condition is derived to separate between higher collision energies where translation energy spectroscopy is problem free and lower energies where strong overlap of individual spectra features prohibits an analysis of the total translation energy spectrum by means of a simple deconvolution procedure. 8 refs., 6 figs.

Magnetar crust electron capture for {sup 55}Co and {sup 56}Ni

Energy Technology Data Exchange (ETDEWEB)

Liu, Jing-Jing; Liu, Dong-Mei [Hainan Tropical Ocean University, College of Marine Science and Technology, Sanya (China)

2018-01-15

Based on the relativistic mean-field effective interaction principle and random phase approximation theory in superstrong magnetic fields (SMFs), we present an analysis of the influence of SMFs on the electron Fermi energy, nuclear blinding energy, single-particle level structure and electron capture for {sup 55}Co, and {sup 56}Ni by the shell-model Monte Carlo method in the magnetar's crust. The electron capture rates increase by two orders of magnitude due to an increase in the electron Fermi energy and a change in single-particle level structure by SMFs. Then the rates decrease by more than two orders of magnitude due to an increase in the nuclear binding energy and a reduction in the electron Fermi energy by SMFs. (orig.)

Electron correlations in single-electron capture from helium by fast protons and α particles

International Nuclear Information System (INIS)

Mancev, Ivan; Milojevic, Nenad

2010-01-01

Single-electron capture from heliumlike atomic systems by bare projectiles is investigated by means of the four-body boundary-corrected first Born approximation (CB1-4B). The effect of the dynamic electron correlation is explicitly taken into account through the complete perturbation potential. The quantum-mechanical post and prior transition amplitudes for single charge exchange encompassing symmetric and/or asymmetric collisions are derived in terms of two-dimensional real integrals in the case of the prior form and five-dimensional quadratures for the post form. An illustrative computation is performed for single-electron capture from helium by protons and α particles at intermediate and high impact energies. The role of dynamic correlations is examined as a function of increased projectile energy. The validity and utility of the proposed CB1-4B method is critically assessed in comparison with the existing experimental data for total cross sections, and excellent agreement is obtained.

K-electron capture probability in 171Lu

International Nuclear Information System (INIS)

Mishra, N.R.; Vara Prasad, N.V.S.; Chandrasekhara Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L.; Chintalapudi, S.N.

1999-01-01

The K-electron capture probability in the decay of 171 Lu to the 835.06 keV level of the daughter nucleus 171 Yb is measured to be 0.822 ± 0.027 involving two transitions, in agreement with the theoretical value 0.833. The experimental value is seen to be consistent with the mass prediction of the relationship due to Wapstra and Bos. (author)

Electron capture by highly stripped ions

International Nuclear Information System (INIS)

Greenland, P.T.

1981-06-01

This review describes theories of electron capture suitable for the description of rearrangement collisions between atomic hydrogen and completely stripped projectiles with charge greater than unity. The region of impact velocity considered lies between 0.05 and 3 au, which is of technological importance in fusion power devices. The semiclassical, impact parameter formalism is discussed and the use of atomic expansions at medium impact velocity is described. Experimental results for both completely and partially stripped projectiles are reviewed. The use of a molecular basis at low energy, and the role of pseudocrossings peculiar to the two centre Coulomb interaction are described. Finally, purely classical techniques, in which the electron wavefunction is represented by an ensemble of Kepler orbits are considered. The review was completed in February 1981. (author)

Electron capture cross-section of Au-Fe complex in silicon

International Nuclear Information System (INIS)

Ali, Akbar; Shafi, M; Majid, Abdul

2006-01-01

A deep level transient spectroscopy technique is applied to study the capture cross-section of an iron-gold complex. The thermal ionization energy obtained from emission rate data is found to be E c -0.36 eV. The Au-Fe complex is a single defect having a capture cross-section of 2.48x10 -16 cm 2 for electrons which is independent of temperature

Differential cross sections for single-electron capture in He{sup 2+}-D collisions

Energy Technology Data Exchange (ETDEWEB)

Bordenave-Montesquieu, D.; Dagnac, R. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France)]|[Toulouse-3 Univ., 31 (France)

1995-06-14

A translational energy spectroscopy technique was used to study single-electron capture into the He{sup +} (n = 2) and He{sup +} (n 3) states in He{sup 2+}-D collisions. Differential cross sections were determined at 4, 6 and 8 keV in the angular range 5`-1{sup o}30` (laboratory frame). As expected, single-electron capture into the n = 2 state was found to be the dominant process; total cross sections for capture into the He{sup +} (n = 3) state were compared to other experimental and theoretical results. (author).

Measurements of Pair Production and Electron Capture from the Continuum in Heavy Particle Collisions

CERN Multimedia

2002-01-01

Large transient Coulomb fields, which are generated in collisions of high-Z systems at sufficiently high energies, lead to copious production of electron-positron pairs. It has been suggested that these lepton pairs might mask signals arising from plasma phase interaction. Pair-production cross sections have been calculated by several authors with results which differ significantly from each other. Some of the electrons produced may be captured into bound states of the ion, thereby, reducing its charge state by one unit. This process which has been termed ``Electron Capture from Pair Production``, represents the only electron capture pro which increases with energy, and as such, will dominate all others in the ultrarelativistic energy regime. Ions having undergone this process would be lost from storage-type accelerators. The absolute cross sections for capture have been calculated with results which differ by as much as an order of magnitude. If as large as some of the calculations predict, Relativistic Heav...

Electron capture cross-section of Au-Fe complex in silicon

Energy Technology Data Exchange (ETDEWEB)

Ali, Akbar; Shafi, M; Majid, Abdul [Advance Materials Physics Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan)

2006-10-15

A deep level transient spectroscopy technique is applied to study the capture cross-section of an iron-gold complex. The thermal ionization energy obtained from emission rate data is found to be E{sub c} -0.36 eV. The Au-Fe complex is a single defect having a capture cross-section of 2.48x10{sup -16} cm{sup 2} for electrons which is independent of temperature.

Accelerated Electron-Beam Formation with a High Capture Coefficient in a Parallel Coupled Accelerating Structure

Science.gov (United States)

Chernousov, Yu. D.; Shebolaev, I. V.; Ikryanov, I. M.

2018-01-01

An electron beam with a high (close to 100%) coefficient of electron capture into the regime of acceleration has been obtained in a linear electron accelerator based on a parallel coupled slow-wave structure, electron gun with microwave-controlled injection current, and permanent-magnet beam-focusing system. The high capture coefficient was due to the properties of the accelerating structure, beam-focusing system, and electron-injection system. Main characteristics of the proposed systems are presented.

Detection efficiency for radionuclides decaying by electron capture and gamma-Ray

International Nuclear Information System (INIS)

Grau, A.; Fernandez, A.

1985-01-01

In this paper, the electron capture partial counting efficiency vs the figure of merit for electron-capture and gamma-ray emitters has been computed. The radionuclides tabulated are 48 c r, 54 M n, 57 C o 56 N i, 72 S e, 73 A s, 85 S r, 88 Z r, 92 N b, 103 P d, 111 l n, 119 S b, 125 I , 139 C e and 152 D y. It has been assumed that the liquid is a toluene based scintillator solution in standard glass vials containing 15 cm 3 . (Author) 17 refs

Electron capture to the continuum from atomic hydrogen

International Nuclear Information System (INIS)

Glass, G.A.; Engar, P.; Berry, S.D.; Breinig, M.; Deserio, R.; Elston, S.B.; Sellin, I.A.

1984-01-01

The first known measurement of the differential cross section for electron capture to the continuum(ECC) from atomic hydrogen is presented. A 12 MeV beam of C 6+ ions traversed a static target of atomic hydrogen produced by an electron impact heated dissociation oven. The resulting ECC spectrum was obtained with a channel electron multiplier detector mounted at the exit of a 160 0 spherical sector electrostatic spectrometer with an angular acceptance of 2 0 . The ECC spectrum clearly shows the asymmetry generally associated with ECC spectra from gaseous targets. The ratio of the singly differential cross section of H to that of H 2 was found to be 0.80. 16 references, 3 figures

Gamow-Teller strength distributions and electron capture rates for 55Co and 56Ni

International Nuclear Information System (INIS)

Nabi, Jameel-Un; Rahman, Muneeb-Ur

2005-01-01

The Gamow-Teller strength (GT) distributions and electron capture rates on 55 Co and 56 Ni have been calculated using the proton-neutron quasiparticle random phase approximation theory. We calculate these weak interaction mediated rates over a wide temperature (0.01x10 9 -30x10 9 K) and density (10-10 11 gcm -3 ) domain. Electron capture process is one of the essential ingredients involved in the complex dynamics of supernova explosion. Our calculations of electron capture rates show differences with the reported shell model diagonalization approach calculations and are comparatively enhanced at presupernova temperatures. We note that the GT strength is fragmented over many final states

Determination of the Electron Neutrino Mass from Experiments on Electron-Capture Beta-Decay (EC)

CERN Multimedia

2002-01-01

The aim of the programme is to measure the electron-neutrino mass, for which at present an upper limit of 500~eV is known. \\\\ \\\\ The experiment studies the shape of the internal bremsstrahlung spectrum in electron-capture near its upper end-point and deduces a mass from small shape changes completely analogous to those in the well-known determination of the electron antineutrino mass in the tritium beta-minus decay. \\\\ \\\\ In a low-energy bremsstrahlung process, the capture takes place from a virtual S state associated with a radiative P~@A~S electromagnetic transition, and the resonant nature of the process leads to important enhancements of the photon intensities at low energy, in particular near the resonance energies co (X-rays). This effect gives this type of experiment a chance to compete with experiments on continuous beta spectra. \\\\ \\\\ The programme concentrates on two long-lived isotopes: \\\\ \\\\ 1)~~|1|6|3Ho. The Q value for this isotope has been found to be 2.6-2.7 keV. A detector specially construct...

Can the neutrino mass be measured using /sup 163/Ho electron capture

International Nuclear Information System (INIS)

Bennett, C.L.

1985-01-01

The safest limit on the neutrino mass comes from allowing the interference amplitude to be a free parameter in a fit to Springer's inner bremsstrahlung data while fixing the Q value to its upper limit based on the results of the relative capture rates from F. Hartmann's data. Since /sup 163/Ho was the most promising electron capture candidate for a neutrino mass detector, it is unlikely that electron capture will ever compete with tritium beta decay in terms of sensitivity to neutrino mass. The best fundamental thing that can be said is that the limit of the difference in the mass of the neutrino and its anti-particle is smaller in absolute value than for any other fermion anti-fermion pair

Search for two-neutrino double electron capture on 124Xe with the XMASS-I detector

Directory of Open Access Journals (Sweden)

K. Abe

2016-08-01

Full Text Available Double electron capture is a rare nuclear decay process in which two orbital electrons are captured simultaneously in the same nucleus. Measurement of its two-neutrino mode would provide a new reference for the calculation of nuclear matrix elements whereas observation of its neutrinoless mode would demonstrate lepton number violation. A search for two-neutrino double electron capture on 124Xe is performed using 165.9 days of data collected with the XMASS-I liquid xenon detector. No significant excess above background was observed and we set a lower limit on the half-life as 4.7×1021 years at 90% confidence level. The obtained limit has ruled out parts of some theoretical expectations. We obtain a lower limit on the 126Xe two-neutrino double electron capture half-life of 4.3×1021 years at 90% confidence level as well.

Double K-shell ionization in electron capture decay

International Nuclear Information System (INIS)

Intemann, R.L.

1985-01-01

Using a semirelativistic theory previously developed by the author, we have computed the total probability per K-capture event for the ionization of the remaining K electron for a dozen nuclides of interest. Based on hydrogenic wave functions and accurate to relative order (Zα) 2 , the theory takes into account the correlation between the two initial K electrons and permits adjustments for screening. Numerical results exhibiting the effects of screening are presented. A comprehensive comparison of the predictions of this theory, as well as those of other theoretical models, with recent experimental data is also given

ANISOTROPY EFFECTS IN ELECTRON-CAPTURE BY O6+ FROM ALIGNED NA-ASTERISK(3P)

NARCIS (Netherlands)

SCHLATMANN, AR; WIERSEMA, WP; HOEKSTRA, R; MORGENSTERN, R; OLSON, RE; PASCALE, J

1994-01-01

We report results of one electron capture by highly charged ions colliding with laser excited aligned Na*(3p). The 0 vi(10-->8) photon emission cross section after electron capture by the O6+ projectile is measured in the collision energy range 2-8 keV/amu. Effects of the Na*(3p) orbital alignment

Electron capture isotopes as cosmic ray 'hydrometers'

International Nuclear Information System (INIS)

Raisbeck, G.M.; Comstock, G.; Perron, C.; Yiou, F.

1975-01-01

Following our earlier work, a computer program has been developed to investigate in detail the survival of pure electron capture isotopes in cosmic rays as a function of their propagation conditions. It is found that this survival is very insensitive to certain parameters such as the type of path length distribution, but very sensitive to the density of the medium in which they are formed. Observation of these isotopes may thus provide clues as to this density. (orig.) [de

Kappa. -electron capture probability in sup 167 Tm

Energy Technology Data Exchange (ETDEWEB)

Sree Krishna Murty, G.; Chandrasekhar Rao, M.V.S.; Radha Krishna, K.; Bhuloka Reddy, S.; Satyanarayana, G.; Ramana Rao, P.V.; Sastry, D.L. (Andhra Univ., Visakhapatnam (India). Labs. for Nuclear Research); Chintalapudi, S.N. (Variable Energy Cyclotron Centre, Calcutta (India))

1990-07-01

The {Kappa}-electron capture probability in the decay of {sup 167}Tm for the first-forbidden transition 1/2{sup +}{yields}3/2{sup -} was measured using the sum-coincidence method and employing a hyper-pure Ge system. The P{sub {Kappa}} value is found to be 0.835{plus minus}0.029, in agreement with the theoretical value of 0.829. (author).

Limit on the radiative neutrinoless double electron capture of ^{36}Ar from GERDA Phase I

Science.gov (United States)

Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Barros, N.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; di Vacri, A.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Fedorova, O.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Heusser, G.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schütz, A.-K.; Schulz, O.; Schwingenheuer, B.; Selivanenko, O.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Stepaniuk, M.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wilsenach, H.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

2016-12-01

Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of ^{36}Ar has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array ( Gerda) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of ^{36}Ar was established: T_{1/2} > 3.6 × 10^{21} years at 90% CI.

Isomer depletion as experimental evidence of nuclear excitation by electron capture

Science.gov (United States)

Chiara, C. J.; Carroll, J. J.; Carpenter, M. P.; Greene, J. P.; Hartley, D. J.; Janssens, R. V. F.; Lane, G. J.; Marsh, J. C.; Matters, D. A.; Polasik, M.; Rzadkiewicz, J.; Seweryniak, D.; Zhu, S.; Bottoni, S.; Hayes, A. B.; Karamian, S. A.

2018-02-01

The atomic nucleus and its electrons are often thought of as independent systems that are held together in the atom by their mutual attraction. Their interaction, however, leads to other important effects, such as providing an additional decay mode for excited nuclear states, whereby the nucleus releases energy by ejecting an atomic electron instead of by emitting a γ-ray. This ‘internal conversion’ has been known for about a hundred years and can be used to study nuclei and their interaction with their electrons. In the inverse process—nuclear excitation by electron capture (NEEC)—a free electron is captured into an atomic vacancy and can excite the nucleus to a higher-energy state, provided that the kinetic energy of the free electron plus the magnitude of its binding energy once captured matches the nuclear energy difference between the two states. NEEC was predicted in 1976 and has not hitherto been observed. Here we report evidence of NEEC in molybdenum-93 and determine the probability and cross-section for the process in a beam-based experimental scenario. Our results provide a standard for the assessment of theoretical models relevant to NEEC, which predict cross-sections that span many orders of magnitude. The greatest practical effect of the NEEC process may be on the survival of nuclei in stellar environments, in which it could excite isomers (that is, long-lived nuclear states) to shorter-lived states. Such excitations may reduce the abundance of the isotope after its production. This is an example of ‘isomer depletion’, which has been investigated previously through other reactions, but is used here to obtain evidence for NEEC.

The Importance of Electron Captures in Core-Collapse Supernovae

International Nuclear Information System (INIS)

Langanke, K.; Sampaio, J.M.; Martinez-Pinedo, G.

2004-01-01

Nuclear physics plays an essential role in the dynamics of a type II supernova (a collapsing star). Recent advances in nuclear many-body theory allow now to reliably calculate the stellar weak-interaction processes involving nuclei. The most important process is the electron capture on finite nuclei with mass numbers A > 55. It is found that the respective capture rates, derived from modern many-body models, differ noticeably from previous, more phenomenological estimates. This leads to significant changes in the stellar trajectory during the supernova explosion, as has been found in state-of-the-art supernova simulations. (author)

Warm Dark Matter Sterile Neutrinos in Electron Capture and Beta Decay Spectra

Directory of Open Access Journals (Sweden)

O. Moreno

2016-01-01

Full Text Available We briefly review the motivation to search for sterile neutrinos in the keV mass scale, as dark matter candidates, and the prospects to find them in beta decay or electron capture spectra, with a global perspective. We describe the fundamentals of the neutrino flavor-mass eigenstate mismatch that opens the possibility of detecting sterile neutrinos in such ordinary nuclear processes. Results are shown and discussed for the effect of heavy neutrino emission in electron capture in Holmium 163 and in two isotopes of Lead, 202 and 205, as well as in the beta decay of Tritium. We study the deexcitation spectrum in the considered cases of electron capture and the charged lepton spectrum in the case of Tritium beta decay. For each of these cases, we define ratios of integrated transition rates over different regions of the spectrum under study and give new results that may guide and facilitate the analysis of possible future measurements, paying particular attention to forbidden transitions in Lead isotopes.

Memory-based attention capture when multiple items are maintained in visual working memory.

Science.gov (United States)

Hollingworth, Andrew; Beck, Valerie M

2016-07-01

Efficient visual search requires that attention is guided strategically to relevant objects, and most theories of visual search implement this function by means of a target template maintained in visual working memory (VWM). However, there is currently debate over the architecture of VWM-based attentional guidance. We contrasted a single-item-template hypothesis with a multiple-item-template hypothesis, which differ in their claims about structural limits on the interaction between VWM representations and perceptual selection. Recent evidence from van Moorselaar, Theeuwes, and Olivers (2014) indicated that memory-based capture during search, an index of VWM guidance, is not observed when memory set size is increased beyond a single item, suggesting that multiple items in VWM do not guide attention. In the present study, we maximized the overlap between multiple colors held in VWM and the colors of distractors in a search array. Reliable capture was observed when 2 colors were held in VWM and both colors were present as distractors, using both the original van Moorselaar et al. singleton-shape search task and a search task that required focal attention to array elements (gap location in outline square stimuli). In the latter task, memory-based capture was consistent with the simultaneous guidance of attention by multiple VWM representations. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Theory of nuclear excitation by electron capture for heavy ions

Energy Technology Data Exchange (ETDEWEB)

Gagyi-Palffy, A.

2006-07-01

The resonant process of nuclear excitation by electron capture (NEEC) in collisions involving highly-charged ions has been investigated theoretically. NEEC is a rare recombination process in which a free electron is captured into a bound shell of an ion with the simultaneous excitation of the nucleus. Total cross sections for NEEC followed by the radiative decay of the excited nucleus are presented for various collision systems. The possibility to observe the NEEC in scattering experiments with trapped or stored ions was discussed focusing on the cases with the largest calculated resonance strength. As the photons emitted in different channels of the electron recombination process are indistinguishable in the total cross section, the interference between NEEC followed by the radiative decay of the nucleus and radiative recombination was investigated. The angular distribution of the emitted photons in the recombination process provides means to discern the two processes. Angular differential cross sections for the emitted photons in the case of E2 nuclear transitions were presented for several heavy elements. (orig.)

Single-electron capture in He[sup 2+]-D[sub 2] collisions

Energy Technology Data Exchange (ETDEWEB)

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

1994-02-14

Doubly differential cross sections of single-electron capture were measured for He[sup 2+] impinging on a molecular deuterium target. The investigated collision energies are 4, 6 and 8 keV and the scattering angles range from 10' to 2[sup o]30' (laboratory frame). The exothermic capture leading to He[sup +] (1s) + D[sub 2][sup +*] was found to be the most important process at low energies and angles, whereas the endothermic channels leading to dissociative capture become the main processes at high scattering angles, i.e. at small impact parameters. (author).

Single-electron capture in low-energy Ar6+-He collisions

International Nuclear Information System (INIS)

Akguengoer, K.; Kamber, E.Y.; Ferguson, S.M.

1997-01-01

Double differential cross sections for state-selective single-electron capture processes in Ar 6+ -He collisions have been measured at laboratory energies between 75 and 900 eV and scattering angles between 0 and 8 . At the lowest energy, the zero-angle spectrum shows capture into Ar 5+ (4p) to be the most important channel. However, as the scattering angle is increased, a second peak appears at angles ≥2 and becomes more pronounced relative to the 4p capture channel. The energy spectra are interpreted qualitatively in terms of the reaction windows, which are calculated using the single-crossing Landau-Zener model. Total and differential cross sections are also measured and compared with available measurements and calculations. (orig.)

CDW-EIS model for single-electron capture in ion-atom collisions involving multielectronic targets

International Nuclear Information System (INIS)

Abufager, P N; MartInez, A E; Rivarola, R D; Fainstein, P D

2004-01-01

A generalization of the continuum distorted wave eikonal initial state (CDW-EIS) approximation, for the description of single-electron capture in ion-atom collisions involving multielectronic targets is presented. This approximation is developed within the framework of the independent electron model taking particular care of the representation of the bound and continuum target states. Total cross sections for single-electron capture from the K-shell of He, Ne and Ar noble gases by impact of bare ions are calculated. Present results are compared to previous CDW-EIS ones and to experimental data

Multiple electron generation in a sea of electronic states

Science.gov (United States)

Witzel, Wayne; Shabaev, Andrew; Efros, Alexander; Hellberg, Carl; Verne, Jacobs

2009-03-01

In traditional bulk semiconductor photovoltaics (PVs), each photon may excite a single electron-hole, wasting excess energy beyond the band-gap as heat. In nanocrystals, multiple excitons can be generated from a single photon, enhancing the PV current. Multiple electron generation (MEG) may result from Coulombic interactions of the confined electrons. Previous investigations have been based on incomplete or over-simplified electronic-state representations. We present results of quantum simulations that include hundreds of thousands of configuration states and show how the complex dynamics, even in a closed electronic system, yields a saturated MEG effect on a femtosecond timescale. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Low-energy electron collisions with metal clusters: Electron capture and cluster fragmentation

International Nuclear Information System (INIS)

Kresin, V.V.; Scheidemann, A.; Knight, W.D.

1993-01-01

The authors have carried out the first measurement of absolute cross sections for the interaction between electrons and size-resolved free metal clusters. Integral inelastic scattering cross sections have been determined for electron-Na n cluster collisions in the energy range from 0.1 eV to 30 eV. At energies ≤1 eV, cross sections increase with decreasing impact energies, while at higher energies they remain essentially constant. The dominant processes are electron attachment in the low-energy range, and collision-induced fragmentation at higher energies. The magnitude of electron capture cross sections can be quantitatively explained by the effect of the strong polarization field induced in the cluster by the incident electron. The cross sections are very large, reaching values of hundreds of angstrom 2 ; this is due to the highly polarizable nature of metal clusters. The inelastic interaction range for fragmentation collisions is also found to considerably exceed the cluster radius, again reflecting the long-range character of electron-cluster interactions. The important role played by the polarization interaction represents a bridge between the study of collision processes and the extensive research on cluster response properties. Furthermore, insight into the mechanisms of electron scattering is important for understanding production and detection of cluster ions in mass spectrometry and related processes

Electron capture in collisions of S4+ with helium

International Nuclear Information System (INIS)

Wang, J.G.; Stancil, P.C.; Turner, A.R.; Cooper, D.L.; Schultz, D.R.; Rakovic, M.J.; Fritsch, W.; Zygelman, B.

2002-01-01

Charge transfer due to collisions of ground-state S 4+ (3s 2 1 S) ions with helium is investigated for energies between 0.1 meV u -1 and 10 MeV u -1 . Total and state-selective single electron capture (SEC) cross sections and rate coefficients are obtained utilizing the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling (AOCC), classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. Previous data are limited to a calculation of the total SEC rate coefficient using the Landau-Zener model that is, in comparison to the results presented here, three orders of magnitude smaller. The MOCC SEC cross sections at low energy reveal a multichannel interference effect. True double capture is also investigated with the AOCC and CTMC approaches while autoionizing double capture and transfer ionization (TI) is explored with CTMC. SEC is found to be the dominant process except for E>200 keV u -1 when TI becomes the primary capture channel. Astrophysical implications are briefly discussed. (author)

Electron capture in collisions of S4+ with helium

Science.gov (United States)

Wang, J. G.; Turner, A. R.; Cooper, D. L.; Schultz, D. R.; Rakovic, M. J.; Fritsch, W.; Stancil, P. C.; Zygelman, B.

2002-07-01

Charge transfer due to collisions of ground-state S4+(3s2 1S) ions with helium is investigated for energies between 0.1 meV u-1 and 10 MeV u-1. Total and state-selective single electron capture (SEC) cross sections and rate coefficients are obtained utilizing the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling (AOCC), classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. Previous data are limited to a calculation of the total SEC rate coefficient using the Landau-Zener model that is, in comparison to the results presented here, three orders of magnitude smaller. The MOCC SEC cross sections at low energy reveal a multichannel interference effect. True double capture is also investigated with the AOCC and CTMC approaches while autoionizing double capture and transfer ionization (TI) is explored with CTMC. SEC is found to be the dominant process except for E>200 keV u-1 when TI becomes the primary capture channel. Astrophysical implications are briefly discussed.

Comparison of the potentials used for the calculation of the resonant coherent electron capture and loss cross sections

International Nuclear Information System (INIS)

Pauly, N.; Dubus, A.; Roesler, M.

2003-01-01

For incident protons with velocities around 1 a.u., electron capture and loss processes are known to play an important role. In particular, electron emission as well as electronic stopping power are strongly influenced by the charge changing processes. Several different electron capture and loss processes have been identified [Solid State Phys. 43 (1990) 229], i.e. Auger valence band processes, shell processes and resonant coherent processes. In the latter, the incident projectile undergoes a periodic excitation due to the periodic crystalline potential so that an electron can be lost or captured. In the literature, several different choices have been made for the crystalline potential. It is precisely the aim of the present work to review and compare the various potentials used in the literature and to show the influence of this choice on the resonant coherent electron capture and loss cross sections

Single-photon emission associated with double electron capture in F9+ + C collisions

CERN Document Server

Elkafrawy, Tamer; Tanis, John A; Warczak, Andrzej

2016-01-01

Radiative double electron capture (RDEC), the one-step process occurring in ion-atom collisions, has been investigated for bare fluorine ions colliding with carbon. RDEC is completed when two target electrons are captured to a bound state of a projectile simultaneously with the emission of a single photon. This work is a follow-up to our earlier measurement of RDEC for bare oxygen projectiles, thus providing a recipient system free of electron-related Coulomb fields in both cases and allowing for the comparison between the two collision systems as well as with available theoretical studies. The most significant mechanisms of x-ray emission that may contribute to the RDEC energy region as background processes are also addressed.

Classical description of the electron capture to the continuum cusp formation in ion-atom collisions

International Nuclear Information System (INIS)

Illescas, Clara; Pons, B.; Riera, A.

2002-01-01

Classical calculations are used to describe the dynamics of the electron capture to the continuum (ECC) cusp formation in H + +He collisions. We illustrate the frontier character of the ECC electrons between capture and ionization, and confirm that it is a temporary capture, through projectile focusing, that is responsible for the ECC cusp. Furthermore, the cusp is not a divergence smoothed by the experiment, and is slightly shifted from the impact-velocity value because of the residual pull from the target after ionization. This shift is larger the smaller the nuclear velocity

Dynamic plasma screening effects on electron capture process in hydrogenic ion fully stripped ion collisions in dense plasmas

International Nuclear Information System (INIS)

Jung, Y.

1997-01-01

In dense plasmas, dynamic plasma screening effects are investigated on electron capture from hydrogenic ions by past fully stripped ions. The classical Bohr Lindhard model has been applied to obtain the electron capture probability. The interaction potential in dense plasmas is represented in terms of the longitudinal dielectric function. The classical straight-line trajectory approximation is applied to the motion of the projectile ion in order to visualize the electron capture probability as a function of the impact parameter, projectile energy, and plasma parameters. The electron capture probability including the dynamic plasma screening effect is always greater than that including the static plasma screening effect. When the projectile velocity is smaller than the electron thermal velocity, the dynamic polarization screening effect becomes the static plasma screening effect. When the projectile velocity is greater than the plasma electron thermal velocity, the interaction potential is almost unshielded. The difference between the dynamic and static plasma screening effects is more significant for low energy projectiles. It is found that the static screening formula obtained by the Debye Hueckel model overestimates the plasma screening effects on the electron capture processes in dense plasmas. copyright 1997 American Institute of Physics

Electron capture study of Ar[sup 7+] + He(H[sub 2]) by U. V. spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Bouchama, T. (Inst. de Physique, Univ. des Sciences et de la Technologie, Alger (Algeria)); El Motassadeq, A. (Lab. Traitement du Signal et Instrumentation, Univ. Jean Monnet, 42 Saint-Etienne (France)); Salmoun, A. (Univ. Cady Ayad, Marrakech (Morocco)); Druetta, M. (Lab. Traitement du Signal et Instrumentation, Univ. Jean Monnet, 42 Saint-Etienne (France)); Church, D.A. (Dept. of Physics, Texas AM Univ., College Station, TX (United States))

1993-11-01

Partial nl and total cross-sections for the low energy collisions Ar[sup 7+] + He(H[sub 2]) at 35-70 keV have been measured by photon spectroscopy. In addition to single electron capture, one electron capture with excitation of a core electron has been observed and measured. Comparisons with calculations based on the Extended Classical Over-Barrier (ECB) model and the assumption of conservation of angular momentum show good agreement between the experimental and predicted l-distributions. (orig.).

Single and double electron capture in collisions of highly ionized, decelerated Ge ions with Ne

International Nuclear Information System (INIS)

Stoehlker, T.; Kozhuharov, C.; Mokler, P.H.; Olson, R.E.; Stachura, Z.; Warczak, A.

1992-03-01

Experimental cross-sections for non-radiative single and double electron capture from Ne target into H-like Ge ions at low intermediate collision energies (4-12) MeV/u are presented. The results are compared with theoretical calculations and an empirical scaling rule. Information concerning the impact parameter dependence of electron capture is extracted using classical trajectory Monte Carlo calculations. (orig.)

Experiences in running a complex electronic data capture system using mobile phones in a large-scale population trial in southern Nepal

OpenAIRE

Style, S.; Beard, B. J.; Harris-Fry, H.; Sengupta, A.; Jha, S.; Shrestha, B. P.; Rai, A.; Paudel, V.; Thondoo, M.; Pulkki-Brannstrom, A-M; Skordis-Worrall, J.; Manandhar, D. S.; Costello, A.; Saville, N. M.

2017-01-01

The increasing availability and capabilities of mobile phones make them a feasible means of data collection. Electronic Data Capture (EDC) systems have been used widely for public health monitoring and surveillance activities, but documentation of their use in complicated research studies requiring multiple systems is limited. This paper shares our experiences of designing and implementing a complex multi-component EDC system for a community-based four-armed cluster-Randomised Controlled Tria...

Experiences in running a complex electronic data capture system using mobile phones in a large-scale population trial in southern Nepal

OpenAIRE

Style, Sarah; Beard, B. James; Harris-Fry, Helen; Sengupta, Aman; Jha, Sonali; Shrestha, Bhim P.; Rai, Anjana; Paudel, Vikas; Thondoo, Meelan; Pulkki-Brannstrom, Anni-Maria; Skordis-Worrall, Jolene; Manandhar, Dharma S.; Costello, Anthony; Saville, Naomi M.

2017-01-01

ABSTRACT The increasing availability and capabilities of mobile phones make them a feasible means of data collection. Electronic Data Capture (EDC) systems have been used widely for public health monitoring and surveillance activities, but documentation of their use in complicated research studies requiring multiple systems is limited. This paper shares our experiences of designing and implementing a complex multi-component EDC system for a community-based four-armed cluster-Randomised Contro...

State-selective electron capture into He-like U90+ ions in collisions with gaseous targets

International Nuclear Information System (INIS)

Ma, X.; Stoehlker, T.; Brinzanescu, O.; Fritzsche, S.; Ludziejewski, T.; Stachura, Z.; Warczak, A.

2000-11-01

For He-like uranium, a state-selective electron capture study was carried out for relativistic collisions with gaseous targets. In the experiment, the projectile X-ray emission produced by electron capture in collisions of 223 MeV/u U 90+ ions on N 2 , Ar, Kr, and Xe targets was measured in coincidence with down-charged U 89+ projectiles. Due to the large fine structure splitting in heavy ions, the well resolved Balmer transitions observed were used to deduce subshell sensitive cross-sections for electron capture. For this purpose a theoretical spectrum analysis and simulation was performed by taking into account electron cascades from states up to n = 40. The state-selective data are compared with theoretical calculations as a function of target atomic number. An overall agreement is found between the experimental data and the theoretical approaches applied except for the j-sensitive part. (orig.)

Electron capture by fast protons from helium-like ions

International Nuclear Information System (INIS)

Samanta, R.; Purkait, M.

2011-01-01

Four-body formalism of boundary corrected continuum intermediate state (BCCIS-4B) approximation have been applied to calculate the single-electron capture cross sections by fast protons through some helium-like ions in a large energy range from 30-1000 keV. In this model, distortion has been taken into account in the entrance channel. In the final channel, the passive electron plays the role of screening of the target ion. However, continuum states of the projectile and the electron in the field of the residual target ion are included. The comparison of the results is made with those of other theoretical investigations and experimental findings. The present calculated results are found to be in good agreement with the available experimental findings. (authors)

Limit on the radiative neutrinoless double electron capture of "3"6Ar from GERDA Phase I

International Nuclear Information System (INIS)

Agostini, M.; Balata, M.; D'Andrea, V.; Di Vacri, A.; Junker, M.; Laubenstein, M.; Allardt, M.; Domula, A.; Lehnert, B.; Schneider, B.; Wester, T.; Wilsenach, H.; Zuber, K.; Bakalyarov, A.M.; Belyaev, S.T.; Lebedev, V.I.; Zhukov, S.V.; Barabanov, I.; Bezrukov, L.; Doroshkevich, E.; Fedorova, O.; Gurentsov, V.; Kazalov, V.; Kuzminov, V.V.; Lubsandorzhiev, B.; Moseev, P.; Selivanenko, O.; Veresnikova, A.; Yanovich, E.; Barros, N.; Baudis, L.; Benato, G.; Kish, A.; Miloradovic, M.; Mingazheva, R.; Walter, M.; Bauer, C.; Hakenmueller, J.; Heisel, M.; Heusser, G.; Hofmann, W.; Kihm, T.; Kirsch, A.; Knoepfle, K.T.; Lindner, M.; Maneschg, W.; Salathe, M.; Schreiner, J.; Schwingenheuer, B.; Simgen, H.; Smolnikov, A.; Stepaniuk, M.; Wagner, V.; Wegmann, A.; Bellotti, E.; Belogurov, S.; Kornoukhov, V.N.; Bettini, A.; Brugnera, R.; Garfagnini, A.; Medinaceli, E.; Sada, C.; Sturm, K. von; Bode, T.; Csathy, J.J.; Lazzaro, A.; Schoenert, S.; Wiesinger, C.; Borowicz, D.; Brudanin, V.; Egorov, V.; Kochetov, O.; Nemchenok, I.; Rumyantseva, N.; Zhitnikov, I.; Zinatulina, D.; Caldwell, A.; Gooch, C.; Kneissl, R.; Liao, H.Y.; Majorovits, B.; Palioselitis, D.; Schulz, O.; Vanhoefer, L.; Cattadori, C.; Salamida, F.; Chernogorov, A.; Demidova, E.V.; Kirpichnikov, I.V.; Vasenko, A.A.; Falkenstein, R.; Freund, K.; Grabmayr, P.; Hegai, A.; Jochum, J.; Schmitt, C.; Schuetz, A.K.; Frodyma, N.; Misiaszek, M.; Panas, K.; Pelczar, K.; Wojcik, M.; Zuzel, G.; Gangapshev, A.; Gusev, K.; Hemmer, S.; Lippi, I.; Stanco, L.; Hult, M.; Lutter, G.; Inzhechik, L.V.; Klimenko, A.; Lubashevskiy, A.; Macolino, C.; Pandola, L.; Pullia, A.; Riboldi, S.; Shirchenko, M.

2016-01-01

Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of "3"6Ar has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array (Gerda) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of "3"6Ar was established: T_1_/_2 > 3.6 x 10"2"1 years at 90% CI. (orig.)

Limit on the radiative neutrinoless double electron capture of {sup 36}Ar from GERDA Phase I

Energy Technology Data Exchange (ETDEWEB)

Agostini, M.; Balata, M.; D' Andrea, V.; Di Vacri, A.; Junker, M.; Laubenstein, M. [INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi (Italy); Allardt, M.; Domula, A.; Lehnert, B.; Schneider, B.; Wester, T.; Wilsenach, H.; Zuber, K. [Technische Universitaet Dresden, Institut fuer Kern- und Teilchenphysik, Dresden (Germany); Bakalyarov, A.M.; Belyaev, S.T.; Lebedev, V.I.; Zhukov, S.V. [National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Barabanov, I.; Bezrukov, L.; Doroshkevich, E.; Fedorova, O.; Gurentsov, V.; Kazalov, V.; Kuzminov, V.V.; Lubsandorzhiev, B.; Moseev, P.; Selivanenko, O.; Veresnikova, A.; Yanovich, E. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Barros, N. [Technische Universitaet Dresden, Institut fuer Kern- und Teilchenphysik, Dresden (Germany); University of Pennsylvania, Philadelphia, PA (United States); Baudis, L.; Benato, G.; Kish, A.; Miloradovic, M.; Mingazheva, R.; Walter, M. [Physik Institut der Universitaet Zuerich, Zurich (Switzerland); Bauer, C.; Hakenmueller, J.; Heisel, M.; Heusser, G.; Hofmann, W.; Kihm, T.; Kirsch, A.; Knoepfle, K.T.; Lindner, M.; Maneschg, W.; Salathe, M.; Schreiner, J.; Schwingenheuer, B.; Simgen, H.; Smolnikov, A.; Stepaniuk, M.; Wagner, V.; Wegmann, A. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Bellotti, E. [Universita Milano Bicocca, Dipartimento di Fisica, Milan (Italy); INFN Milano Bicocca, Milan (Italy); Belogurov, S.; Kornoukhov, V.N. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Institute for Theoretical and Experimental Physics NRC ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Bettini, A.; Brugnera, R.; Garfagnini, A.; Medinaceli, E.; Sada, C.; Sturm, K. von [Dipartimento di Fisica e Astronomia dell' Universita di Padova, Padua (Italy); INFN Padova, Padua (Italy); Bode, T.; Csathy, J.J.; Lazzaro, A.; Schoenert, S.; Wiesinger, C. [Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Borowicz, D. [Jagiellonian University, Institute of Physics, Krakow (Poland); Joint Institute for Nuclear Research, Dubna (Russian Federation); Brudanin, V.; Egorov, V.; Kochetov, O.; Nemchenok, I.; Rumyantseva, N.; Zhitnikov, I.; Zinatulina, D. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Caldwell, A.; Gooch, C.; Kneissl, R.; Liao, H.Y.; Majorovits, B.; Palioselitis, D.; Schulz, O.; Vanhoefer, L. [Max-Planck-Institut fuer Physik, Munich (Germany); Cattadori, C.; Salamida, F. [INFN Milano Bicocca, Milan (Italy); Chernogorov, A.; Demidova, E.V.; Kirpichnikov, I.V.; Vasenko, A.A. [Institute for Theoretical and Experimental Physics NRC ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Falkenstein, R.; Freund, K.; Grabmayr, P.; Hegai, A.; Jochum, J.; Schmitt, C.; Schuetz, A.K. [Eberhard Karls Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany); Frodyma, N.; Misiaszek, M.; Panas, K.; Pelczar, K.; Wojcik, M.; Zuzel, G. [Jagiellonian University, Institute of Physics, Krakow (Poland); Gangapshev, A. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Gusev, K. [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Technische Universitaet Muenchen, Physik Department and Excellence Cluster Universe, Munich (Germany); Hemmer, S.; Lippi, I.; Stanco, L. [INFN Padova, Padua (Italy); Hult, M.; Lutter, G. [European Commission, JRC-Geel, Geel (Belgium); Inzhechik, L.V. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow (Russian Federation); Moscow Institute of Physics and Technology, Moscow (Russian Federation); Klimenko, A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); International University for Nature, Society and Man ' ' Dubna' ' , Dubna (Russian Federation); Lubashevskiy, A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Macolino, C. [INFN Laboratori Nazionali del Gran Sasso and Gran Sasso Science Institute, Assergi (Italy); LAL, CNRS/IN2P3, Universite Paris-Saclay, Orsay (France); Pandola, L. [INFN Laboratori Nazionali del Sud, Catania (Italy); Pullia, A.; Riboldi, S. [Universita degli Studi di Milano, Dipartimento di Fisica, Milan (Italy); INFN Milano (Italy); Shirchenko, M. [Joint Institute for Nuclear Research, Dubna (Russian Federation); National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation); Collaboration: GERDA collaboration

2016-12-15

Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of {sup 36}Ar has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array (Gerda) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of {sup 36}Ar was established: T{sub 1/2} > 3.6 x 10{sup 21} years at 90% CI. (orig.)

First Calorimetric Measurement of OI-line in the Electron Capture Spectrum of $^{163}$Ho

CERN Document Server

Ranitzsch, P. C. -O.; Wegner, M.; Kempf, S.; Fleischmann, A.; Enss, C.; Gastaldo, L.; Herlert, A.; Johnston, K.

2014-01-01

The isotope $^{163}$Ho undergoes an electron capture process with a recommended value for the energy available to the decay, $Q_{\\rm EC}$, of about 2.5 keV. According to the present knowledge, this is the lowest $Q_{\\rm EC}$ value for electron capture processes. Because of that, $^{163}$Ho is the best candidate to perform experiments to investigate the value of the electron neutrino mass based on the analysis of the calorimetrically measured spectrum. We present for the first time the calorimetric measurement of the atomic de-excitation of the $^{163}$Dy daughter atom upon the capture of an electron from the 5s shell in $^{163}$Ho, OI-line. The measured peak energy is 48 eV. This measurement was performed using low temperature metallic magnetic calorimeters with the $^{163}$Ho ion implanted in the absorber. We demonstrate that the calorimetric spectrum of $^{163}$Ho can be measured with high precision and that the parameters describing the spectrum can be learned from the analysis of the data. Finally, we dis...

A minimal unified model of disease trajectories captures hallmarks of multiple sclerosis

KAUST Repository

Kannan, Venkateshan

2017-03-29

Multiple Sclerosis (MS) is an autoimmune disease targeting the central nervous system (CNS) causing demyelination and neurodegeneration leading to accumulation of neurological disability. Here we present a minimal, computational model involving the immune system and CNS that generates the principal subtypes of the disease observed in patients. The model captures several key features of MS, especially those that distinguish the chronic progressive phase from that of the relapse-remitting. In addition, a rare subtype of the disease, progressive relapsing MS naturally emerges from the model. The model posits the existence of two key thresholds, one in the immune system and the other in the CNS, that separate dynamically distinct behavior of the model. Exploring the two-dimensional space of these thresholds, we obtain multiple phases of disease evolution and these shows greater variation than the clinical classification of MS, thus capturing the heterogeneity that is manifested in patients.

Probabilities and energies to obtain the counting efficiency of electron-capture nuclides, KLMN model

International Nuclear Information System (INIS)

Casas Galiano, G.; Grau Malonda, A.

1994-01-01

An intelligent computer program has been developed to obtain the mathematical formulae to compute the probabilities and reduced energies of the different atomic rearrangement pathways following electron-capture decay. Creation and annihilation operators for Auger and X processes have been introduced. Taking into account the symmetries associated with each process, 262 different pathways were obtained. This model allows us to obtain the influence of the M-electron-capture in the counting efficiency when the atomic number of the nuclide is high

SO{sub 2} retention by reactivated CaO-based sorbent from multiple CO{sub 2} capture cycles

Energy Technology Data Exchange (ETDEWEB)

Vasilije Manovic; Edward J. Anthony [CANMET Energy Technology Centre-Ottawa, Ottawa, ON (Canada). Natural Resources Canada

2007-06-15

This paper examines the reactivation of spent sorbent, produced from multiple CO{sub 2} capture cycles, for use in SO{sub 2} capture. CaO-based sorbent samples were obtained from Kelly Rock limestone using three particle size ranges, each containing different impurities levels. Using a thermogravimetric analyzer (TGA), the sulfation behavior of partially sulfated and unsulfated samples obtained after multiple calcination-carbonation cycles in a tube furnace (TF), following steam reactivation in a pressurized reactor, is examined. In addition, samples calcined/sintered under different conditions after hydration are also examined. The results show that suitably treated spent sorbent has better sulfation characteristics than that of the original sorbent. Thus for example, after 2 h sulfation, {gt} 80% of the CaO was sulfated. In addition, the sorbent showed significant activity even after 4 h when {gt} 95% CaO was sulfated. The results were confirmed by X-ray diffraction (XRD) analysis, which showed that, by the end of the sulfation process, samples contained CaSO{sub 4} with only traces of unreacted CaO. The superior behavior of spent reactivated sorbent appears to be due to swelling of the sorbent particles during steam hydration. The surface area morphology of sorbent after reactivation was examined by scanning electron microscopy (SEM). Ca(OH){sub 2} crystals were seen, which displayed their regular shape, and their elemental composition was confirmed by energy-dispersive X-ray (EDX) analysis. These results allow the proposal of a new process for the use of CaO-based sorbent in fluidized bed combustion (FBC) systems, which incorporates CO{sub 2} capture, sorbent reactivation, and SO{sub 2} retention. 26 refs., 4 figs., 2 tabs.

Electron capture in ion atom and ion-ion collisions

International Nuclear Information System (INIS)

Barat, M.

1986-01-01

Electron capture (EC) by positive ions in collision with various targets has remained one of the most important subjects of research since the early 30's. From a theoretical point of view, EC is obviously a coupled 3-body problem: at least two cores and an active electron that jumps between them. Practical interest in EC arose in a variety of fields. Recently a renewed interest arose from the physics of thermonuclear fusion, where capture by highly charged ionic impurities were found to be an important process in tokamak devices. For that reasons, a number of reviews were devoted to this subject during the past years, including lectures given in various NATO advanced science institutes. The aim of this lecture is not at all to add a new review to this list, but (i) to summarize the very basis of the present theoretical approaches at low and moderate collision energy, (ii) to pinpoint some crucial difficulties in the theoretical treatment, (iii) to select specific examples which, to the taste of the author, reflect some present practical interest, or some significant advances. 48 references, 38 figures, 1 table

Theoretical treatment of electron capture and excitation in two-electron system ion-atom, atom-atom collisions at low to intermediate energy

International Nuclear Information System (INIS)

Kimura, M.

1986-01-01

A review of various theoretical treatments which have been used to study electron-capture and excitation processes in two-electron-system ion-atom, atom-atom collisions at low to intermediate energy is presented. Advantages as well as limitations associated with these theoretical models in application to practical many-electron ion-atom, atom-atom collisions are specifically pointed out. Although a rigorous theoretical study of many-electron systems has just begun so that reports of theoretical calculations are scarce to date in comparison to flourishing experimental activities, some theoretical results are of great interest and provide important information for understanding collision dynamics of the system which contains many electrons. Selected examples are given for electron capture in a multiply charged ion-He collision, ion-pair formation in an atom-atom collision and alignment and orientation in a Li + + He collision. (Auth.)

A mobile and asynchronous electronic data capture system for epidemiologic studies.

Science.gov (United States)

Meyer, Jens; Fredrich, Daniel; Piegsa, Jens; Habes, Mohamad; van den Berg, Neeltje; Hoffmann, Wolfgang

2013-06-01

A Central Data Management (CDM) system based on electronic data capture (EDC) software and study specific databases is an essential component for assessment and management of large data volumes in epidemiologic studies. Conventional CDM systems using web applications for data capture depend on permanent access to a network. However, in many study settings permanent network access cannot be guaranteed, e.g. when participants/patients are visited in their homes. In such cases a different concept for data capture is needed. The utilized EDC software must be able to ensure data capture as stand-alone instance and to synchronize captured data with the server at a later point in time. This article describes the design of the mobile information capture (MInCa) system an EDC software meeting these requirements. In particular, we focus on client and server design, data synchronization, and data privacy as well as data security measures. The MInCa software has already proven its efficiency in epidemiologic studies revealing strengths and weaknesses concerning both concept and practical application which will be addressed in this article. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Single electron capture by state-prepared Ar2+ projectiles in Ar

International Nuclear Information System (INIS)

Puerta, J.; Huber, B.A.

1985-03-01

Electron capture by state-selected Ar 2+ projectiles in Ar has been studied at low collision energies ( 2+ ions are measured explaining existing discrepancies of partial and total cross sections in the Ar 2+ /Ar collision system. Although highly excited metastable ions ( 5 D 4 0 , 3 F 4 0 ) represent a minor contamination of a non-prepared Ar 2+ beam (proportional1%), their contributions are found to dominate the capture process due to cross section values larger than 10 -15 cm 2 . (orig.)

Measurement of the activity of electron capturing isotopes

International Nuclear Information System (INIS)

Szoerenyi, A.

1980-01-01

In order to measure precisely the activity of electron capturing isotopes, an equipment was constructed for the detection the X-photons, the Auger- and the conversing electrons by a high-pressure, gas-flow 4π proportional counter. The proportional counter and the NaI(Tl) scintillation counter are placed in a common lead-shielding, thus, the equipment is suited for the measurement of radioisotopes decaying in coincidence. The structure of the proportional counter and of the pressure-control system are detailed. As an example, the energy spectra of a 109 Cd solution, taken at different pressures, are published. At a pressure of 1.1 MPa the 3 peaks are well separated. The results of an international test, in which the radioactivity of a 57 Co sample was determined, are published, too. (L.E.)

Electron capture from H(2s) by H+ at low energies

International Nuclear Information System (INIS)

Blanco, S.A.; Falcon, C.A.; Piacentini, R.D.

1986-01-01

Total cross sections for resonant electron capture by protons from metastable H(2s) targets have been computed in a six-state molecular close-coupling formalism. Transitions between degenerate sublevels of the L shell of the target occurring at large internuclear distances have been taken into account in the impact parameter approximation. Cross sections are presented for impact velocities between 0.05 and 0.3 au. The results are compared with theoretical calculations for capture from H(2s) by Li 3+ , C 6+ and N 7+ . (author)

Radiative double electron capture in fast heavy ion-atom collisions

International Nuclear Information System (INIS)

Yakhontov, V.L.; Amusia, M.Ya.

1996-01-01

Two-electron capture with emission of a single photon (TESP) in collisions of highly charged ions with light atoms is considered. Such a process is actually a time-reversed double photoionization but occurring at specific kinematics. In the lowest order in the inter-electron interaction, the TESP probability is determined by two diagrams which are evaluated analytically by means of the Coulomb Green function. The calculated ratio of the TESP and single recombination cross sections is in fair agreement with the data obtained in the recent experimental study of this phenomena. (orig.)

Interpretation of second Born amplitudes in electron capture

International Nuclear Information System (INIS)

McGuire, J.H.; Simony, P.R.; Weaver, O.L.; Macek, J.

1982-01-01

Exact sound Born amplitudes for 1s-1s electron capture are presented and interpreted in terms of contributions from intermediate states off the energy shell and on the energy shell. The classical model of Thomas corresponds to two-step scattering via one particular on-shell intermediate state. In the high-velocity limit for 1s-1s capture, this on-shell intermediate state of the Thomas model accounts for one-half of the total cross section, i.e., the second Born cross section. The other half comes from off-energy-shell intermediate states near the on-shell Thomas state. Above 5 MeV both the off-shell and on-shell amplitudes have a simple structure near the Thomas peak. Below 1 MeV, contributions from a broader range of intermediate states are evident in the amplitudes. Although the contribution from the Thomas state is not large below 1 MeV, other second Born effects are significant

Enzyme catalysis captured using multiple structures from one crystal at varying temperatures

Directory of Open Access Journals (Sweden)

Sam Horrell

2018-05-01

Full Text Available High-resolution crystal structures of enzymes in relevant redox states have transformed our understanding of enzyme catalysis. Recent developments have demonstrated that X-rays can be used, via the generation of solvated electrons, to drive reactions in crystals at cryogenic temperatures (100 K to generate `structural movies' of enzyme reactions. However, a serious limitation at these temperatures is that protein conformational motion can be significantly supressed. Here, the recently developed MSOX (multiple serial structures from one crystal approach has been applied to nitrite-bound copper nitrite reductase at room temperature and at 190 K, close to the glass transition. During both series of multiple structures, nitrite was initially observed in a `top-hat' geometry, which was rapidly transformed to a `side-on' configuration before conversion to side-on NO, followed by dissociation of NO and substitution by water to reform the resting state. Density functional theory calculations indicate that the top-hat orientation corresponds to the oxidized type 2 copper site, while the side-on orientation is consistent with the reduced state. It is demonstrated that substrate-to-product conversion within the crystal occurs at a lower radiation dose at 190 K, allowing more of the enzyme catalytic cycle to be captured at high resolution than in the previous 100 K experiment. At room temperature the reaction was very rapid, but it remained possible to generate and characterize several structural states. These experiments open up the possibility of obtaining MSOX structural movies at multiple temperatures (MSOX-VT, providing an unparallelled level of structural information during catalysis for redox enzymes.

Influence of Magnetic Field Decay on Electron Capture in Magnetars ...

Indian Academy of Sciences (India)

Abstract. The de-excited energy of electron capture (EC) induced by magnetic field decay may be a new source for heating magnetar crust, so we do a quantitative calculation on EC process near the outer crust and analyse their influence on persistent X-ray radiation of magnetars, adopt- ing the experimental data or the ...

Electron capture and excitation processes in H+-H collisions in dense quantum plasmas

Science.gov (United States)

Jakimovski, D.; Markovska, N.; Janev, R. K.

2016-10-01

Electron capture and excitation processes in proton-hydrogen atom collisions taking place in dense quantum plasmas are studied by employing the two-centre atomic orbital close-coupling (TC-AOCC) method. The Debye-Hückel cosine (DHC) potential is used to describe the plasma screening effects on the Coulomb interaction between charged particles. The properties of a hydrogen atom with DHC potential are investigated as a function of the screening strength of the potential. It is found that the decrease in binding energy of nl levels with increasing screening strength is considerably faster than in the case of the Debye-Hückel (DH) screening potential, appropriate for description of charged particle interactions in weakly coupled classical plasmas. This results in a reduction in the number of bound states in the DHC potential with respect to that in the DH potential for the same plasma screening strength, and is reflected in the dynamics of excitation and electron capture processes for the two screened potentials. The TC-AOCC cross sections for total and state-selective electron capture and excitation cross sections with the DHC potential are calculated for a number of representative screening strengths in the 1-300 keV energy range and compared with those for the DH and pure Coulomb potential. The total capture cross sections for a selected number of screening strengths are compared with the available results from classical trajectory Monte Carlo calculations.

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

Calculation of current-voltage characteristics of electron-capture detectors

International Nuclear Information System (INIS)

Hinneburg, D.; Grosse, H.J.; Leonhardt, J.; Popp, P.

1983-01-01

Starting from the law of conservation of charge a stationary one-dimensional non-linear differential equation system is derived, which is applied to the direct-current mode of an electron-capture detector with parallel electrode plates. The theory takes into account space-charge, recombination, and inhomogeneous ionization and it deals with three kinds of charge carriers with different mobilities (positive and negative ions, electrons). Terms due to diffusion and gas-flow losses are excluded. The equations so constructed were programmed to get a means of calculating the charge and field distributions and the current-voltage characteristics as functions of various parameters of the detectors, the attaching gas and the ionization. For two cases the results are given. (author)

Spectroscopy of electrons ejected after charge exchange between multicharged ions and atoms

International Nuclear Information System (INIS)

Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Boujema, M.; Gleizes, A.

1988-01-01

This report concerns a study of two-electron capture into autoionizing states from helium and hydrogen targets. Possible capture mechanisms are discussed. Also multiple-capture processes involving more than two electrons are discussed. 41 refs.; 9 figs.; 1 table

Electron capture into excited states of multi-charged ions

International Nuclear Information System (INIS)

Dijkkamp, D.

1985-01-01

This thesis deals with charge exchange reactions in slow collisions of multi-charged ions with neutral atoms or molecules. These reactions proceed very efficiently via a curve crossing mechanism, which leads to preferential population of excited states of the ion. The subsequent decay of these states leads to the emission of characteristic radiation. From wavelength resolved measurements of the absolute intensity of this radiation, cross sections for selective population of the excited (n,l-) states of the ion were determined. In addition, for some systems the total capture cross section was measured directly by means of charge state analysis of the secondary projectile ions. The role of charge exchange processes in fusion plasmas and in astrophysical plasmas is indicated. An experimental set-up is described with emphasis on the Electron Cyclotron Resonance Ion Source that was used in the experiments. Results for collisions of C 6+ , N 6+ , O 6+ and Ne 6+ with He, H 2 and Ar are presented as well as for electron capture from Li atoms by C 4+ and He 2+ . The interaction of the iso-electronic sequence C 4+ , N 5+ , O 6+ with atomic hydrogen, molecular hydrogen and helium is studied. First results for partial and total cross sections in collisions of fully stripped carbon, nitrogen and oxygen ions with atomic hydrogen are presented. These data are of particular importance for applications in fusion diagnostics. The data indicate that calculations of both molecular and atomic orbital type yield correct results, if an extended basis set is used. (Auth.)

Radiative capture of slow electrons by tungsten surface

International Nuclear Information System (INIS)

Artamonov, O.M.; Belkina, G.M.; Samarin, S.N.; Yakovlev, I.I.

1987-01-01

Isochromatic spectra of radiation capture of slow electrons by the surface of mono- and polycrystal tungsten recorded on 322 and 405 nm wave lengths are presented. The effect of oxygen adsorption on isochromates of the (110) face of tungsten monocrystal is investigated. The obtained isochromatic spectra are compared with energy band structure of tungsten. Based on the analysis of the obtained experimental results it is assumed that optical transition to the final state at the energy of 7.3 eV relatively to Fermi level is conditioned by surface states of the tungsten face (110)

Electron capture and ionization in collisions of multiply charged ions with H(2s)

International Nuclear Information System (INIS)

Errea, L F; Guzman, F; Illescas, Clara; Mendez, L; Pons, B; Riera, A; Suarez, J

2007-01-01

We present total cross sections for electron capture and ionization in collisions of B 5+ and Ne 10+ with H(2s), calculated using two methods: the semiclassical close-coupling molecular formalism and the eikonal-CTMC method. We have evaluated partial cross sections for capture into excited n-levels, required in plasma diagnostics

Molecular treatment of single (dissociative and nondissociative) and double electron capture in He2+ + H2 collisions

International Nuclear Information System (INIS)

Errea, L F; Macias, A; Mendez, L; Pons, B; Riera, A

2003-01-01

We present close-coupling calculations of total cross sections for single and double electron capture in He 2+ + H 2 collisions in the range 0.5- 25 keV amu -1 , and compare them with experimental data. We confirm the experimental finding that the dominant process for E ∼> 3 keV amu -1 is the nondissociative capture He 2+ + H 2 → He + (2l) + H 2 + (1σ g ), while at lower energies it is dissociative capture leading to He + (1s) + H + + H. Our calculations also show that He(1s2l) is the main output of the two electron capture process. (letter to the editor)

Quantum effects on the formation of negative hydrogen ion by polarization electron capture in partially ionized dense hydrogen plasmas

International Nuclear Information System (INIS)

Jung, Young-Dae; Kato, Daiji

2009-05-01

The quantum effects on the formation of the negative hydrogen ion (H - ) by the polarization electron capture process are investigated in partially ionized dense hydrogen plasmas. It is shown that the quantum effect strongly suppresses the electron capture radius as well as the cross section for the formation of the negative hydrogen ion. In addition, it has been found that the electron capture position is receded from the center of the projectile with decreasing the quantum effect of the plasma. (author)

Electron capture dissociation proceeds with a low degree of intramolecular migration of peptide amide hydrogens

DEFF Research Database (Denmark)

Rand, Kasper D; Adams, Christopher M; Zubarev, Roman A

2008-01-01

scrambling) that occurs during vibrational excitation of gas-phase ions. Unlike traditional collisional ion activation, electron capture dissociation (ECD) is not associated with substantial vibrational excitation. We investigated the extent of intramolecular backbone amide hydrogen (1H/2H) migration upon...... ECD using peptides with a unique selective deuterium incorporation. Our results show that only limited amide hydrogen migration occurs upon ECD, provided that vibrational excitation prior to the electron capture event is minimized. Peptide ions that are excessively vibrationally excited...

Measurement on K-electron capture probabilities in the decay of [sup 183]Re and [sup 168]Tm

Energy Technology Data Exchange (ETDEWEB)

Prasad, N.V.S.V.; Rao, M.V.S.C.; Reddy, S.B.; Satyanarayana, G.; Sastry, D.L. (Andhra Univ., Visakhapatnam (India). Swami Jnanananda Labs. for Nuclear Research); Murty, G.S.K. (UNDNJ, Newark, NJ (United States). Dept. of Radiology); Chintalapudi, S.N. (Inter University Consortium for DAE Facilities, Calcutta (India))

1994-03-01

The K-electron capture probabilities for the 5/2[sup +] to 3/2[sup -]transition in the electron capture decay of [sup 183]Re to the 208.805 keV level in the daughter [sup 183]W and for the 3[sup (+)] to 3[sup -]and 3[sup (+)] to 4[sup -] transitions in the electron capture decay of [sup 168]Tm to the 1541.4 keV and 1093.0 keV levels, respectively, in the daughter [sup 168]Er were measured for the first time using an x-[gamma] summing method. The experimental P[sub K] values are reported in this paper, together with those due to theory, and discussed. (Author).

The Skyrme-TQRPA calculations of electron capture on hot nuclei in pre-supernova environment

Energy Technology Data Exchange (ETDEWEB)

Dzhioev, Alan A., E-mail: dzhioev@theor.jinr.ru; Vdovin, A. I., E-mail: vdovin@theor.jinr.ru [JINR, Bogoliubov Laboratory of Theoretical Physics (Russian Federation); Stoyanov, Ch., E-mail: stoyanov@inrne.bas.bg [Bulgarian Academy of Sciences, Institute for Nuclear Research and Nuclear Energy (Bulgaria)

2016-11-15

We combine the thermal QRPA approach with the Skyrme energy density functional theory (Skyrme–TQRPA) for modelling the process of electron capture on nuclei in supernova environment. For a sample nucleus, {sup 56}Fe, the Skyrme–TQRPA approach is applied to analyze thermal effects on the strength function of GT{sub +} transitions which dominate electron capture at E{sub e} ≤ 30 MeV. Several Skyrme interactions are used in order to verify the sensitivity of the obtained results to the Skyrme force parameters. Finite-temperature cross sections are calculated and the results are comparedwith those of the other model calculations.

Radiative double-electron capture in collisions of fast heavy ions with solid carbon targets

International Nuclear Information System (INIS)

Yakhontov, V.L.; Amusia, M.Y.

1997-01-01

Two-electron capture with an emission of a single photon (TESP) in collisions of highly charged ions with light atoms is considered. Such a process is actually a time-reversed double photoionization but occurring at specific kinematics. In the lowest order in the interelectron interaction, the TESP probability is determined by two diagrams which are evaluated analytically by means of the Coulomb Green close-quote s function. The calculated ratio of the radiative double-electron capture and single recombination cross sections is in fair agreement with the data obtained in the recent experimental study of this phenomenon. copyright 1997 The American Physical Society

Electron capture in proton collisions with alkali atoms as a three-body problem

International Nuclear Information System (INIS)

Avakov, G.V.; Blokhintsev, L.D.; Kadyrov, A.S.; Mukhamedzhanov, A.M.

1992-01-01

A previous paper proposed an approach to the calculation of electron transfer reactions in ion-atomic collisions based on the Faddeev three-body equations written in the Alt-Grassberger-Sandhas form. In the present work this approach is used to describe the electron capture in proton collisions with alkali atoms. The results of calculation of the total and partial cross sections for charge exchange in proton collisions with Li, Na, K and Rb atoms are presented. The calculated total cross sections are in good agreement with experiment for light target atoms. In going over to heavier targets, the theoretical total cross sections, while agreeing in form, tend to be larger than the experimental ones. The calculated partial cross sections for electron capture into the 2s state of the H atom are also in agreement with experiment. Some other partial cross sections were also calculated. (author)

Electron-capture negative-ion mass spectrometry: a technique for environmental contaminant identification

International Nuclear Information System (INIS)

Stemmler, E.A.

1986-01-01

Electron capture negative ion mass spectrometry (ECNIMS) is a method used to generate negative ions in a mass spectrometer by electron-molecule reactions. This technique facilitates the sensitive and selective detection of many toxic contaminants in environmental samples. Applications of this technique have been hindered by the limited understanding of instrumental parameters, by the questionable reproducibility of negative ion mass spectra, and by the inability to interpret negative ion mass spectra. Instrumental parameters which were important to control include the ion source temperature, ion source pressure, sample concentration, and the focus lens potential. The ability to obtain reproducible spectra was demonstrated by measurement of the spectrum of decafluorotriphenylphosphine (DFTPP) over a period of one year. Negative ion fragmentation mechanisms were studied by measuring the spectra of structurally related classes of compounds and isotopically labelled compounds. These results were combined with data obtained by other researchers. Fragmentations characteristic of particular functional groups or molecular structures have been summarized. From this data set, guidelines for the interpretation of electron capture negative ion mass spectra have been developed

Electron capture in collisions of S{sup 4+} with helium

Energy Technology Data Exchange (ETDEWEB)

Wang, J.G.; Stancil, P.C. [Department of Physics and Astronomy and Center for Simulational Physics, University of Georgia, Athens, GA (United States)]. E-mails: wangjg@physast.uga.edu; stancil@physast.uga.edu; Turner, A.R.; Cooper, D.L. [Department of Chemistry, University of Liverpool (United Kingdom)]. E-mail: dlc@liv.ac.uk; Schultz, D.R.; Rakovic, M.J. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)]. E-mails: schultzd@ornl.gov; milun@mail.phy.ornl.gov; Fritsch, W. [Abteilung Theoretische Physik, Hahn-Meitner-Institut Berlin, Berlin (Germany)]. E-mail: fritsch@hmi.de; Zygelman, B. [Department of Physics, University of Nevada, Las Vegas, NV (United States)]. E-mail: bernard@physics.unlv.edu

2002-07-28

Charge transfer due to collisions of ground-state S{sup 4+}(3s{sup 2} {sup 1}S) ions with helium is investigated for energies between 0.1 meV u{sup -1} and 10 MeV u{sup -1}. Total and state-selective single electron capture (SEC) cross sections and rate coefficients are obtained utilizing the quantum mechanical molecular-orbital close-coupling (MOCC), atomic-orbital close-coupling (AOCC), classical trajectory Monte Carlo (CTMC) and continuum distorted wave methods. The MOCC calculations utilize ab initio adiabatic potentials and nonadiabatic radial coupling matrix elements obtained with the spin-coupled valence-bond approach. Previous data are limited to a calculation of the total SEC rate coefficient using the Landau-Zener model that is, in comparison to the results presented here, three orders of magnitude smaller. The MOCC SEC cross sections at low energy reveal a multichannel interference effect. True double capture is also investigated with the AOCC and CTMC approaches while autoionizing double capture and transfer ionization (TI) is explored with CTMC. SEC is found to be the dominant process except for E>200 keV u{sup -1} when TI becomes the primary capture channel. Astrophysical implications are briefly discussed. (author)

Studing electronic structure of water molecules in aquocomplexes by the method of pions minus capture by hydrogen

International Nuclear Information System (INIS)

Dezhi, I.; Krumshtejn, Z.V.; Molnar, B.; Petrukhin, V.I.; Rybakov, V.N.; Suvorov, V.M.; Khorvat, D.; Tsisek, Z.; Yutlandov, I.A.

1980-01-01

Using the effect of electron shell state on π-meson capture by chemically bound hydrogen studied has been change of electron density in hydrogen atoms of water molecules bound into aquocomplexes. The fact of depression of π-meson capture probability by hydrogen of water in aquocomplexes has been established. The magnitudes of depression indicate essential decrease of electron density in a hydrogen atom of coordinated water. Interaction of ligands with oxygen-containing anions also essentially contributes to a magnitude of depression

Studies of collision mechanisms in electron capture by slow multiply charged ions

International Nuclear Information System (INIS)

Gilbody, H B; McCullough, R W

2004-01-01

We review measurements based on translational energy spectroscopy which are being used to identify and assess the relative importance of the various collision mechanisms involved in one-electron capture by slow multiply charged ions in collisions with simple atoms and molecules

Neutrino Signals in Electron-Capture Storage-Ring Experiments

Directory of Open Access Journals (Sweden)

Avraham Gal

2016-06-01

Full Text Available Neutrino signals in electron-capture decays of hydrogen-like parent ions P in storage-ring experiments at GSI are reconsidered, with special emphasis placed on the storage-ring quasi-circular motion of the daughter ions D in two-body decays P → D + ν e . It is argued that, to the extent that daughter ions are detected, these detection rates might exhibit modulations with periods of order seconds, similar to those reported in the GSI storage-ring experiments for two-body decay rates. New dedicated experiments in storage rings, or using traps, could explore these modulations.

Capture dynamics of hot electrons on quantum dots in RTDs studied by noise measurement

International Nuclear Information System (INIS)

Hees, S S; Kardynal, B E; Shields, A J; Farrer, I; Ritchie, D A

2008-01-01

We investigate the noise in quantum dot resonant tunnelling diodes (QDRTDs), where the quantum dots (QDs) placed in the collector experience electric fields that vary in a wide range. The trapping/detrapping of electrons on the QDs dominated the measured electrical noise. The model that we derived for the noise explains the experimental data well. The QD capture cross-section is one to two orders of magnitude smaller than the physical size of the QDs due to the reduced probability of capturing a hot electron on the QD. The model is a powerful tool to design the noise characteristics of QDRTD single photon-detectors

An electron-microscopical analysis of capture and initial stages of penetration of nematodes by Arthrobotrys oligospora

NARCIS (Netherlands)

Veenhuis, Marten; Nordbring-Hertz, Birgit; Harder, Wim

1985-01-01

A detailed analysis was made of the capture and subsequent penetration of nematodes by the nematophagous fungus Arthrobotrys oligospora using different electron-microscopical techniques. Capture of nematodes by this fungus occurred on complex hyphal structures (traps) and was effectuated by an

Electron capture probabilities in sup 105 Ag

Energy Technology Data Exchange (ETDEWEB)

Chandrasekhar Rao, M.V.S.; Sree Krishna Murty, G.; Radha Krishna, K.; Bhuloka Reddy, S.; Satyanarayana, G.; Raghavaiah, C.V.; Sastry, D.L. (Andhra Univ., Visakhapatnam (India). Labs. for Nuclear Research); Chintalapudi, S.N. (Bhabha Atomic Research Centre, Calcutta (India). Variable Energy Cyclotron Centre)

1990-01-01

The K-electron capture probabilities for the 1/2{sup -}yields3/2{sup -} and 1/2{sup -}yields1/2{sup +} transitions in the decay of {sup 105}Ag were measured for the first time using the sum coincidence method. The experimental P{sub K} values were estimated to be 0.824{plus minus}0.042 and 0.851{plus minus}0.046 for the allowed and first-forbidden beta transitions, respectively in agreement with the theory. The P{sub L} experimental values to these two levels were also computed using the experimental P{sub L}/P{sub K} values reported by earlier authors. These results are also found to be consistent with the theoretical P{sub L} values. (orig.).

Ion-induced ionization and capture cross sections for DNA nucleobases impacted by light ions

International Nuclear Information System (INIS)

Champion, Christophe; Hanssen, Jocelyn; Galassi, Mariel E; Fojón, Omar; Rivarola, Roberto D; Weck, Philippe F

2012-01-01

Two quantum mechanical models (CB1 and CDW-EIS) are here presented for describing electron ionization and electron capture induced by heavy charged particles in DNA bases. Multiple differential and total cross sections are determined and compared with the scarce existing experimental data.

Pair production with electron capture in peripheral collisions of relativistic heavy ions

Energy Technology Data Exchange (ETDEWEB)

Bertulani, C.A.C.A. E-mail: bertu@if.ufrj.br; Dolci, D.D. E-mail: dolci@if.ufrj.br

2001-02-26

The production of electron-positron pairs with the capture of the electron in an atomic orbital is investigated for the conditions of the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). Dirac wave functions for the leptons are used, taking corrections to orders of Z{alpha} into account. The dependence on the transverse momentum transfer is studied and the accuracy of the equivalent photon approximation is discussed as a function of the nuclear charge.

Electron Capture Dissociation of Weakly Bound Polypeptide Polycationic Complexes

DEFF Research Database (Denmark)

Haselmann, Kim F; Jørgensen, Thomas J D; Budnik, Bogdan A

2002-01-01

as well as specific complexes of modified glycopeptide antibiotics with their target peptide. The weak nature of bonding is substantiated by blackbody infrared dissociation, low-energy collisional excitation and force-field simulations. The results are consistent with a non-ergodic ECD cleavage mechanism.......We have previously reported that, in electron capture dissociation (ECD), rupture of strong intramolecular bonds in weakly bound supramolecular aggregates can proceed without dissociation of weak intermolecular bonds. This is now illustrated on a series of non-specific peptide-peptide dimers...

77 FR 4059 - Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof; Receipt...

Science.gov (United States)

2012-01-26

... INTERNATIONAL TRADE COMMISSION [DN 2869] Certain Electronic Devices for Capturing and Transmitting... Interest AGENCY: U.S. International Trade Commission. ACTION: Notice. SUMMARY: Notice is hereby given that the U.S. International Trade Commission has received a complaint entitled In Re Certain Electronic...

Contingent attentional capture across multiple feature dimensions in a temporal search task.

Science.gov (United States)

Ito, Motohiro; Kawahara, Jun I

2016-01-01

The present study examined whether attention can be flexibly controlled to monitor two different feature dimensions (shape and color) in a temporal search task. Specifically, we investigated the occurrence of contingent attentional capture (i.e., interference from task-relevant distractors) and resulting set reconfiguration (i.e., enhancement of single task-relevant set). If observers can restrict searches to a specific value for each relevant feature dimension independently, the capture and reconfiguration effect should only occur when the single relevant distractor in each dimension appears. Participants identified a target letter surrounded by a non-green square or a non-square green frame. The results revealed contingent attentional capture, as target identification accuracy was lower when the distractor contained a target-defining feature than when it contained a nontarget feature. Resulting set reconfiguration was also obtained in that accuracy was superior when the current target's feature (e.g., shape) corresponded to the defining feature of the present distractor (shape) than when the current target's feature did not match the distractor's feature (color). This enhancement was not due to perceptual priming. The present study demonstrated that the principles of contingent attentional capture and resulting set reconfiguration held even when multiple target feature dimensions were monitored. Copyright © 2015 Elsevier B.V. All rights reserved.

The β+-electron capture decay of 73Kr

International Nuclear Information System (INIS)

Miehe, C.; Dessagne, P.; Pujol, Ch.; Walter, G.; Jonson, B.; Lindroos, M.

1999-01-01

The β + - electron capture decay of 73 Kr, produced at the ISOLDE CERN facility, has been studied by β-delayed proton and gamma emission. The established decay scheme involves 15 up to now unreported gamma emitting levels in 73 Br. The total proton branching ratio has been measured to be 0.0025±0.0003. From this work, a spin and parity 3/2 - is assigned to the 73 Kr ground state, on the basis of the allowed β branch to the 73 Br J π =1/2 - ground state and the feeding of the 5/2 + level located at 286 keV in 73 Br. (orig.)

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)

Electron-electron interaction in Multiple Quantum Wells

Science.gov (United States)

Zybert, M.; Marchewka, M.; Tomaka, G.; Sheregii, E. M.

2012-07-01

The complex investigation of the magneto-transport effects in structures containing multiple quantum well (MQWs) based on the GaAs/AlGaAs-heterostructures has been performed. The MQWs investigated have different electron densities in QWs. The parameters of 2DEG in MQWs were determined from the data of the Integer Quantum Hall Effect (IQHE) and Shubnikov-de Haas oscillations (SdH) observed at low temperatures (0.6-4.2 K). The method of calculation of the electron states energies in MQWs has been developed which is based on the splitting of these states due to the exchange interaction (SAS-splitting, see D. Płoch et al., Phys. Rev. B 79 (2009) 195434) including the screening of this interaction. The IQHE and SdH observed in these multilayer structures with the third degree of freedom for electrons are interpreted from this.

Aptamer-based hydrogel barcodes for the capture and detection of multiple types of pathogenic bacteria.

Science.gov (United States)

Xu, Yueshuang; Wang, Huan; Luan, Chengxin; Liu, Yuxiao; Chen, Baoan; Zhao, Yuanjin

2018-02-15

Rapid and sensitive diagnosing hematological infections based on the separation and detection of pathogenic bacteria in the patient's blood is a significant challenge. To address this, we herein present a new barcodes technology that can simultaneously capture and detect multiple types of pathogenic bacteria from a complex sample. The barcodes are poly (ethylene glycol) (PEG) hydrogel inverse opal particles with characteristic reflection peak codes that remain stable during bacteria capture on their surfaces. As the spherical surface of the particles has ordered porous nanostructure, the barcodes can provide not only more surface area for probe immobilization and reaction, but also a nanopatterned platform for highly efficient bioreactions. In addition, the PEG hydrogel scaffold could decrease the non-specificity adsorption by its anti-adhesive effect, and the decorated aptamer probes in the scaffolds could increase the sensitivity, reliability, and specificity of the bacteria capture and detection. Moreover, the tagged magnetic nanoparticles in the PEG scaffold could impart the barcodes with controllable movement under magnetic fields, which can be used to significantly increase the reaction speed and simplify the processing of the bioassays. Based on the describe barcodes, it was demonstrated that the bacteria could be captured and identified even at low bacterial concentrations (100 CFU mL -1 ) within 2.5h, which is effectively shortened in comparison with the "gold standard" in clinic. These features make the barcodes ideal for capturing and detecting multiple bacteria from clinical samples for hematological infection diagnostics. Copyright © 2017 Elsevier B.V. All rights reserved.

Application of a distorted wave model to electron capture in atomic collisions

International Nuclear Information System (INIS)

Deco, G.R.; Martinez, A.E.; Rivarola, R.D.

1988-01-01

In this work, it is presented the CDW-EIS approximation applied to the description of processes of electron capture in ion-atom collisions. Differential and total cross sections are compared to results obtained by other theoretical models, as well as, to experimental data. (A.C.A.S.) [pt

Monitoring compliance with transfusion guidelines in hospital departments by electronic data capture

DEFF Research Database (Denmark)

Norgaard, Astrid; De Lichtenberg, Trine Honnens; Nielsen, Jens

2014-01-01

-transfusion haemoglobin levels at the departmental level. In a tertiary care hospital, no such data were produced before this study. Our aim was to establish a Patient Blood Management database based on electronic data capture in order to monitor compliance with transfusion guidelines at departmental and hospital levels...

Effect of collective response on electron capture and excitation in collisions of highly charged ions with fullerenes.

Science.gov (United States)

Kadhane, U; Misra, D; Singh, Y P; Tribedi, Lokesh C

2003-03-07

Projectile deexcitation Lyman x-ray emission following electron capture and K excitation has been studied in collisions of bare and Li-like sulphur ions (of energy 110 MeV) with fullerenes (C(60)/C(70)) and different gaseous targets. The intensity ratios of different Lyman x-ray lines in collisions with fullerenes are found to be substantially lower than those for the gas targets, both for capture and excitation. This has been explained in terms of a model based on "solidlike" effect, namely, wakefield induced stark mixing of the excited states populated via electron capture or K excitation: a collective phenomenon of plasmon excitation in the fullerenes under the influence of heavy, highly charged ions.

Removal of nonorthogonality in the Born theory used for study of electron capture in high energy ion-atom collisions

International Nuclear Information System (INIS)

Kimura, M.

1989-01-01

We show the complete removal of the nonorthogonality of wave functions between initial and final states in the Born theory. Hence, this treatment offers more realistic electron capture cross sections in high energy ion-atom collisions. Representative results for resonant electron capture in H + + H collision are discussed in conjunction with other perturbative results. 10 refs., 1 fig

Electron capture in collisions of Si3+ ions with atomic hydrogen from low to intermediate energies

Science.gov (United States)

Liu, C. H.; Liu, L.; Wang, J. G.

2014-07-01

The electron capture process for the Si3+(3s) + H(1s) collisions is investigated by the quantum-mechanical molecular orbital close-coupling (MOCC) method and by the two-center atomic orbital close-coupling (AOCC) method in the energy range of 10-5-10 keV/u and 0.8-200 keV/u, respectively. Total and state-selective cross sections are presented and compared with the available theoretical and experimental results. The present MOCC and AOCC results agree well with the experimental measurements, but show some discrepancy with the calculations of Wang et al. [Phys. Rev. A 74, 052709 (2006), 10.1103/PhysRevA.74.052709] at E > 40 eV/u because of the inclusion of rotational couplings, which play important roles in the electron capture process. At lower energies, the present results are about three to five times smaller than those of Wang et al. due to the difference in the molecular data at large internuclear distances. The energy behaviors of the electron capture cross sections are discussed on the basis of identified reaction mechanisms.

Electron Raman scattering in asymmetrical multiple quantum wells

International Nuclear Information System (INIS)

Betancourt-Riera, R; Rosas, R; Marin-Enriquez, I; Riera, R; Marin, J L

2005-01-01

Optical properties of asymmetrical multiple quantum wells for the construction of quantum cascade lasers are calculated, and expressions for the electronic states of asymmetrical multiple quantum wells are presented. The gain and differential cross-section for an electron Raman scattering process are obtained. Also, the emission spectra for several scattering configurations are discussed, and the corresponding selection rules for the processes involved are studied; an interpretation of the singularities found in the spectra is given. The electron Raman scattering studied here can be used to provide direct information about the efficiency of the lasers

The feasibility of using 'bring your own device' (BYOD) technology for electronic data capture in multicentre medical audit and research.

Science.gov (United States)

Faulds, M C; Bauchmuller, K; Miller, D; Rosser, J H; Shuker, K; Wrench, I; Wilson, P; Mills, G H

2016-01-01

Large-scale audit and research projects demand robust, efficient systems for accurate data collection, handling and analysis. We utilised a multiplatform 'bring your own device' (BYOD) electronic data collection app to capture observational audit data on theatre efficiency across seven hospital Trusts in South Yorkshire in June-August 2013. None of the participating hospitals had a dedicated information governance policy for bring your own device. Data were collected by 17 investigators for 392 individual theatre lists, capturing 14,148 individual data points, 12, 852 (91%) of which were transmitted to a central database on the day of collection without any loss of data. BYOD technology enabled accurate collection of a large volume of secure data across multiple NHS organisations over a short period of time. Bring your own device technology provides a method for collecting real-time audit, research and quality improvement data within healthcare systems without compromising patient data protection. © 2015 The Association of Anaesthetists of Great Britain and Ireland.

Identification and measurement of chlorinated organic pesticides in water by electron-capture gas chromatography

Science.gov (United States)

Lamar, William L.; Goerlitz, Donald F.; Law, LeRoy M.

1965-01-01

Pesticides, in minute quantities, may affect the regimen of streams, and because they may concentrate in sediments, aquatic organisms, and edible aquatic foods, their detection and their measurement in the parts-per-trillion range are considered essential. In 1964 the U.S. Geological Survey at Menlo Park, Calif., began research on methods for monitoring pesticides in water. Two systems were selected--electron-capture gas chromatography and microcoulometric-titration gas chromatography. Studies on these systems are now in progress. This report provides current information on the development and application of an electron-capture gas chromatographic procedure. This method is a convenient and extremely sensitive procedure for the detection and measurement of organic pesticides having high electron affinities, notably the chlorinated organic pesticides. The electron-affinity detector is extremely sensitive to these substances but it is not as sensitive to many other compounds. By this method, the chlorinated organic pesticide may be determined on a sample of convenient size in concentrations as low as the parts-per-trillion range. To insure greater accuracy in the identifications, the pesticides reported were separated and identified by their retention times on two different types of gas chromatographic columns.

Single electron capture in ion-atom collisions involving multielectronic targets

International Nuclear Information System (INIS)

Abufager, P.N.; Martinez, A.E.; Rivarola, R.D.; Fainstein, P.D.

2005-01-01

The generalized continuum distorted wave-eikonal initial state (GCDW-EIS) approximation is employed to study single electron capture by impact of protons on Ne and Ar targets. We analyze the contributions to the total cross sections coming from the different target shells. Present results are compared with theoretical calculations obtained using the previous CDW-EIS formulation and to experimental data in order to show the importance of the description of the bound and continuum target states in the entry and exit channels, respectively

Multiple Sensor Camera for Enhanced Video Capturing

Science.gov (United States)

Nagahara, Hajime; Kanki, Yoshinori; Iwai, Yoshio; Yachida, Masahiko

A resolution of camera has been drastically improved under a current request for high-quality digital images. For example, digital still camera has several mega pixels. Although a video camera has the higher frame-rate, the resolution of a video camera is lower than that of still camera. Thus, the high-resolution is incompatible with the high frame rate of ordinary cameras in market. It is difficult to solve this problem by a single sensor, since it comes from physical limitation of the pixel transfer rate. In this paper, we propose a multi-sensor camera for capturing a resolution and frame-rate enhanced video. Common multi-CCDs camera, such as 3CCD color camera, has same CCD for capturing different spectral information. Our approach is to use different spatio-temporal resolution sensors in a single camera cabinet for capturing higher resolution and frame-rate information separately. We build a prototype camera which can capture high-resolution (2588×1958 pixels, 3.75 fps) and high frame-rate (500×500, 90 fps) videos. We also proposed the calibration method for the camera. As one of the application of the camera, we demonstrate an enhanced video (2128×1952 pixels, 90 fps) generated from the captured videos for showing the utility of the camera.

AMUC: Associated Motion capture User Categories.

Science.gov (United States)

Norman, Sally Jane; Lawson, Sian E M; Olivier, Patrick; Watson, Paul; Chan, Anita M-A; Dade-Robertson, Martyn; Dunphy, Paul; Green, Dave; Hiden, Hugo; Hook, Jonathan; Jackson, Daniel G

2009-07-13

The AMUC (Associated Motion capture User Categories) project consisted of building a prototype sketch retrieval client for exploring motion capture archives. High-dimensional datasets reflect the dynamic process of motion capture and comprise high-rate sampled data of a performer's joint angles; in response to multiple query criteria, these data can potentially yield different kinds of information. The AMUC prototype harnesses graphic input via an electronic tablet as a query mechanism, time and position signals obtained from the sketch being mapped to the properties of data streams stored in the motion capture repository. As well as proposing a pragmatic solution for exploring motion capture datasets, the project demonstrates the conceptual value of iterative prototyping in innovative interdisciplinary design. The AMUC team was composed of live performance practitioners and theorists conversant with a variety of movement techniques, bioengineers who recorded and processed motion data for integration into the retrieval tool, and computer scientists who designed and implemented the retrieval system and server architecture, scoped for Grid-based applications. Creative input on information system design and navigation, and digital image processing, underpinned implementation of the prototype, which has undergone preliminary trials with diverse users, allowing identification of rich potential development areas.

Probabilities and energies to obtain the counting efficiency of electron-capture nuclides. KLMN model

International Nuclear Information System (INIS)

Galiano, G.; Grau, A.

1994-01-01

An intelligent computer program has been developed to obtain the mathematical formulae to compute the probabilities and reduced energies of the different atomic rearrangement pathways following electron-capture decay. Creation and annihilation operators for Auger and X processes have been introduced. Taking into account the symmetries associated with each process, 262 different pathways were obtained. This model allows us to obtain the influence of the M-electro capture in the counting efficiency when the atomic number of the nuclide is high. (Author)

Correlated electron capture and inner-shell excitation measurements in ion-atom collisions

International Nuclear Information System (INIS)

Tanis, J.A.; Bernstein, E.M.; Clark, M.W.

1985-01-01

In an ion-atom collision projectile excitation and charge transfer (electron capture) may occur together in a single encounter. If the excitation and capture are correlated, then the process is called resonant transfer and excitation (RTE); if they are uncorrelated, then the process is termed nonresonant transfer and excitation (NTE). Experimental work to date has shown the existence of RTE and provided strong evidence for NTE. Results presented here provide information on the relative magnitudes of RTE and NTE, the charge state dependence of RTE, the effect of the target momentum distribution on RTE, the magnitude of L-shell RTE compared to K-shell RTE, and the target Z dependences of RTE and NTE. 15 refs., 5 figs

Electron Capture in Slow Collision of He^2++H : Revisited

Science.gov (United States)

Krstic, Ps

2003-05-01

Very early experimental data (Fite et al. al., Proc. R. Soc. A 268, 527 (1962)) for He^2++H, recent ORNL measurements for Ne^2+ + H and our theoretical estimates suggest that the electron capture cross sections for these strongly exoergic collision systems drop slower toward low collision energies than expected from previous theories. We perform a theoretical study to establish and understand the true nature of this controversy. The calculations are based on the Hidden Crossings MOCC method, augmented with rotational and turning point effects.

Photon-mediated electron multiplication in liquid xenon doped with trimethylamine

International Nuclear Information System (INIS)

Sano, Toshio; Ashikaga, Kinya; Doke, Tadayoshi; Hitachi, Akira; Kikuchi, Jun; Masuda, Kimiaki; Okumura, Yasuaki

1989-01-01

Electron multiplication mediated by photons has been observed in liquid xenon doped with trimethylamine in concentrations of 0, 9.3, 43, 118 and 400 ppm. The effect was observed by irradiating a single wire counter with 1 MeV electrons and gamma rays from 207 Bi sources. The multiplication factor was observed to increase from a value of 23 at a concentration of 9.3 ppm to a value of 45 at a concentration of 118 ppm. Over the same range of concentrations, the threshold anode voltage for photon-mediated electron multiplication (PMEM) decreased from 2.5 to 1.4 kV and the PMEM results in a deterioration of energy resolution. At a concentration of 400 ppm, the resulting electron multiplication was neither stable nor reproducible. (orig.)

Continuum capture in the three-body problem

International Nuclear Information System (INIS)

Sellin, I.A.

1980-01-01

The three-body problem, especially the problem of electron capture to the continuum in heavy particle collisions is reviewed. Major topics covered include: second born-induced asymmetry in electron capture to the continuum; historical context, links to other tests of atomic scattering theory; experiments characterizing the velocity distribution of ECC electrons; other atomic physics tests of high velocity Born expansions; atom capture; capture by positrons; and pion capture to the continuum

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)

Statistics of electron multiplication in multiplier phototube: iterative method

International Nuclear Information System (INIS)

Grau Malonda, A.; Ortiz Sanchez, J.F.

1985-01-01

An iterative method is applied to study the variation of dynode response in the multiplier phototube. Three different situations are considered that correspond to the following ways of electronic incidence on the first dynode: incidence of exactly one electron, incidence of exactly r electrons and incidence of an average anti-r electrons. The responses are given for a number of steps between 1 and 5, and for values of the multiplication factor of 2.1, 2.5, 3 and 5. We study also the variance, the skewness and the excess of jurtosis for different multiplication factors. (author)

Electron capture and transfer-ionization processes in {sup 4}He{sup 2+}+Ar collision at 12.5 keV amu{sup -1}

Energy Technology Data Exchange (ETDEWEB)

Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A.; Benhenni, M. [Laboratoire Collisions, Agregats, Reactivite, IRSAMC, UMR 5589 CNRS and Universite Paul Sabatier, 31062 Toulouse Cedex (France)

1998-05-14

Electron emission in the {sup 4}He{sup 2+}+Ar collisional system has been investigated at 35 deg. and 12.5 keV amu{sup -1} collision velocity, in coincidence with the recoil target ion charges. Direct single ionization is found to be negligible with respect to single-electron capture. Contributions of transfer-ionization processes are stressed in the production of Ar{sup 2+} to Ar{sup 4+} ions; those of direct ionization, double excitation of the target and double capture into autoionization states of helium are instead found to be much less probable. Among the two-electron processes which explain the formation of Ar{sup 2+} ions, the double capture into autoionizing states of helium remains unimportant with respect to a pure transfer ionization process (one captured electron plus one ionized electron). The measured predominant production of Ar{sup 3+} ions illustrates the role played by three-electron processes, mainly a two-electron transfer accompanied by a single-target ionization. Finally, the formation of Ar{sup 4+} ions is connected with more complex transfer ionization processes. A qualitative analysis of these results is made within the quasimolecular approach. (author). Letter-to-the-editor.

Studies of electron correlation effects in multicharged ion atom collisions involving double capture

International Nuclear Information System (INIS)

Stolterfoht, N.; Sommer, K.; Griffin, D.C.; Havener, C.C.; Huq, M.S.; Phaneuf, R.A.; Swenson, J.K.; Meyer, F.W.

1988-01-01

We review measurements of L-Coster Kronig and Auger electron production in slow, multicharged collision systems to study electron correlation effects in the process of double electron capture. The n/sup /minus/3/ law was confirmed for the production of the Coster-Kronig configurations 1s 2 2pn/ell/ (n ≥ 6) in O 6+ + He collisions. Enhancement of high angular momentum /ell/ in specific 1s 2 2pn/ell/ configurations was observed by means of high-resolution measurements of the Coster-Kronig lines. The importance of electron correlation effects in couplings of potential energy curves leading to the 1s 2 2pn/ell/ configurations is verified by means of Landau-Zener model calculations. 32 refs., 4 figs

Radiative electron capture for F8+ and F9+ ions in collisions with a He gas target

International Nuclear Information System (INIS)

Kawatsura, K.; Richard, P.; Tawara, H.

1981-01-01

The x rays from the radiative electron capture (REC) to the projectile K-shell were investigated for F 8+ and F 9+ ions incident on the He target atoms in the projectile energy range from 15 to 40 MeV. The peak energies of the K-REC x-ray spectra were found to decrease linearly with a decrease of the projectile energies as expected and extrapolated to the correct ls binding energies at zero velocity. According to theory the distribution width of the REC energies should be independent of the binding energy of electrons in the projectile ions. However, it is found that this width for F 8+ ions is systematically smaller by 20% than that for F 9+ ions. The measured REC cross sections for F 9+ ions are slightly larger than twice those for F 8+ ions and the total REC cross sections for F 8+ and F 9+ ions were found to be more than three orders of magnitude smaller than the total electron capture cross sections and the capture cross sections into excited states

Negative meson capture in hydrogen

International Nuclear Information System (INIS)

Baird, T.J.

1977-01-01

The processes of deexcitation and capture of negative mesons and hadrons in atomic hydrogen are investigated. Only slow collisions in which the projectile-atom relative velocity is less than one atomic unit are considered, and the motion of the incident particle is treated classically. For each classical trajectory the probability of ionizing the hydrogen atom is determined, together with the energy spectrum of the emitted electron. Ionization probabilities are calculated using the time-dependent formulation of the perturbed stationary state method. Exact two-center electronic wave functions are used for both bound and continuum states. The total ionization cross section and electron energy spectrum have been calculated for negative muons, kaons and antiprotons at incident relative velocities between 0.04 and 1.0 atomic units. The electron energy spectrum has a sharp peak for electron kinetic energies on the order of 10 -3 Rydbergs. The ionization process thus favors the emission of very slow electrons. The cross section for ionization with capture of the incident particle was calculated for relative kinetic energies greater than 1.0 Rydberg. Since ionization was found to occur with the emission of electrons of nearly zero kinetic energy, the fraction of ionizing collisions which result in capture decreases very rapidly with projectile kinetic energy. The energy distributions of slowed down muons and hadrons were also computed. These distributions were used together with the capture cross section to determine the distribution of kinetic energies at which capture takes place. It was found that most captures occur for kinetic energies slightly less than 1.0 Rydbergs with relatively little capture at thermal energies. The captured particles therefore tend to go into very large and loosely found orbits with binding energies less than 0.1 Rydbergs

Study of gamma ray multiplicity spectra for radiative capture of neutrons in 113,115In

International Nuclear Information System (INIS)

Georgiev, G.P.; Fajkov-Stanchik, Kh.; Grigor'ev, Yu.V.; Muradyan, G.V.; Yaneva, N.B.

1997-08-01

Neutron radiative capture measurements were performed for the enriched isotopes 113 In and 115 In on the neutron spectrometer at the Neutron Physics Laboratory of the Joint Institute for Nuclear Research employing the gamma ray multiplicity technique and using a ''Romashka'' multi-sectional 4p detector on the 500 m time base of the IBR-30 booster. The gamma multiplicity spectra of resolved resonances were obtained for the 20-500 eV energy range. The mean gamma ray multiplicity was determined for each resonance. The dependence of the ratio S of the low-energy coincidence multiplicity spectrum to the high-energy coincidence multiplicity spectrum on resonance energy exhibits a non-statistical structure. This structure was found to correlate with the local neutron strength function. (author). 10 refs, 6 figs, 2 tabs

ELECTRON-CAPTURE FROM LI BY B-5+, N-5+ AND BE-4+ IONS

NARCIS (Netherlands)

HOEKSTRA, R; OLSON, RE; FOLKERTS, HO; WOLFRUM, E; PASCALE, J; DEHEER, FJ; MORGENSTERN, R; WINTER, H

1993-01-01

We present state selective experimental and theoretical results for electron capture in B-5+ and N5+-Li collisons at energies in the range of 1-10 keV amu-1. Experimentally we have used photon emission spectroscopy in the VUV and visible spectral range and theoretically we have performed classical

Large electron capture-cross-section of the major nonradiative recombination centers in Mg-doped GaN epilayers grown on a GaN substrate

Science.gov (United States)

Chichibu, S. F.; Shima, K.; Kojima, K.; Takashima, S.; Edo, M.; Ueno, K.; Ishibashi, S.; Uedono, A.

2018-05-01

Complementary time-resolved photoluminescence and positron annihilation measurements were carried out at room temperature on Mg-doped p-type GaN homoepitaxial films for identifying the origin and estimating the electron capture-cross-section ( σ n ) of the major nonradiative recombination centers (NRCs). To eliminate any influence by threading dislocations, free-standing GaN substrates were used. In Mg-doped p-type GaN, defect complexes composed of a Ga-vacancy (VGa) and multiple N-vacancies (VNs), namely, VGa(VN)2 [or even VGa(VN)3], are identified as the major intrinsic NRCs. Different from the case of 4H-SiC, atomic structures of intrinsic NRCs in p-type and n-type GaN are different: VGaVN divacancies are the major NRCs in n-type GaN. The σ n value approximately the middle of 10-13 cm2 is obtained for VGa(VN)n, which is larger than the hole capture-cross-section (σp = 7 × 10-14 cm2) of VGaVN in n-type GaN. Combined with larger thermal velocity of an electron, minority carrier lifetime in Mg-doped GaN becomes much shorter than that of n-type GaN.

Ultralow energy calibration of LUX detector using Xe 127 electron capture

Science.gov (United States)

Akerib, D. S.; Alsum, S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Brás, P.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; Dobi, A.; Druszkiewicz, E.; Edwards, B. N.; Fallon, S. R.; Fan, A.; Fiorucci, S.; Gaitskell, R. J.; Genovesi, J.; Ghag, C.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Jacobsen, R. G.; Ji, W.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solmaz, M.; Solovov, V. N.; Sorensen, P.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W. C.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Velan, V.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Xu, J.; Yazdani, K.; Young, S. K.; Zhang, C.

2017-12-01

We report an absolute calibration of the ionization yields (Qy ) and fluctuations for electronic recoil events in liquid xenon at discrete energies between 186 eV and 33.2 keV. The average electric field applied across the liquid xenon target is 180 V /cm . The data are obtained using low energy Xe 127 electron capture decay events from the 95.0-day first run from LUX (WS2013) in search of weakly interacting massive particles. The sequence of gamma-ray and x-ray cascades associated with I 127 deexcitations produces clearly identified two-vertex events in the LUX detector. We observe the K-(binding energy, 33.2 keV), L-(5.2 keV), M-(1.1 keV), and N-(186 eV) shell cascade events and verify that the relative ratio of observed events for each shell agrees with calculations. The N-shell cascade analysis includes single extracted electron (SE) events and represents the lowest-energy electronic recoil in situ measurements that have been explored in liquid xenon.

Electron capture in slow collisions of multicharged ions with hydrogen atoms using merged beams

International Nuclear Information System (INIS)

Havener, C.C.; Nesnidal, M.P.; Porter, M.R.; Phaneuf, R.A.

1991-01-01

Absolute total electron-capture cross-section mesurements are reported for collisions of O 3+ and O 4+ with atomic hydrogen in the energy range 1-1000 eV /amu using merged beams. The data are compared with available coupled-states theoretical calculations. (orig.)

Electron capture and loss to continuum states in gases and solids

International Nuclear Information System (INIS)

Sellin, I.A.; Laubert, R.

1981-01-01

A key feature of our experimental procedure is the easy interchange of short gaseous and thin solid targets at the same physical position, with all apparatus aperture sizes, dimensions, positions, and other experimental details unaltered. It has therefore been possible to cancel most systematic apparatus effects in comparing gaseous and solid target results. By using single ion-atom collision techniques, by using bare and few-electron ions of appreciably higher charge than heretofore, by extending the velocity range of measurement appreciably above that of earlier experiments, and by studying charge-state variation over an appreciably wider range than used previously, we have been able to test experimentally features of continuum electron-capture and -loss theories which have been inaccessible in previous experiments. (orig./TW)

Measurement of K-electron capture probability in the decay of 87Y

International Nuclear Information System (INIS)

Prasad, N.V.S.V.; Murty, G.S.K.; Rao, M.V.S.C.; Sastry, D.L.

1993-01-01

The K-electron capture probability for the 1/2 - to 3/2 - transition in the decay of 87 Y to the 873.0 keV level in the daughter 87 Sr was measured for the first time using an x-γ summing method. The experimental P K value was found to be 0.911 ± 0.047, in agreement with the theoretical value of 0.878. (author)

Studies of electron correlation effects in multicharged ion atom collisions involving double capture

Energy Technology Data Exchange (ETDEWEB)

Stolterfoht, N.; Sommer, K.; Griffin, D.C.; Havener, C.C.; Huq, M.S.; Phaneuf, R.A.; Swenson, J.K.; Meyer, F.W.

1988-01-01

We review measurements of L-Coster Kronig and Auger electron production in slow, multicharged collision systems to study electron correlation effects in the process of double electron capture. The n/sup /minus/3/ law was confirmed for the production of the Coster-Kronig configurations 1s/sup 2/2pn/ell/ (n greater than or equal to 6) in O/sup 6 +/ + He collisions. Enhancement of high angular momentum /ell/ in specific 1s/sup 2/2pn/ell/ configurations was observed by means of high-resolution measurements of the Coster-Kronig lines. The importance of electron correlation effects in couplings of potential energy curves leading to the 1s/sup 2/2pn/ell/ configurations is verified by means of Landau-Zener model calculations. 32 refs., 4 figs.

The calorimetric spectrum of the electron-capture decay of $^{163}$Ho. A preliminary analysis of the preliminary data

CERN Document Server

De Rújula, A.

2015-01-01

It is in principle possible to measure directly the electron neutrino mass (or masses and mixing angles) in weak electron-capture decays. The optimal nuclide in this respect is $^{163}$Ho. The favoured experimental technique, currently pursued in various experiments (ECHo, HOLMES and NuMECS) is "calorimetric". The calorimetric energy spectrum is a sum over the unstable vacant orbitals, or "holes", left by the electrons weakly captured by the nucleus. We discuss the current progress in this field and analize the preliminary data. Our conclusion is that, as pointed out by Robertson, the contribution of two-hole states is not negligible. But --in strong contradistinction with the tacit conclusion of previous comparisons of theory and observations-- we find a quite satisfactory agreement. A crucial point is that, in the creation of secondary holes, electron shakeoff and not only electron shakeup must be taken into account.

Electron capture in collisions between O6+ ions and H2O molecules

NARCIS (Netherlands)

Bodewits, D.; Hoekstra, R.

By means of photon emission spectroscopy, state selective electron capture cross section for low energy (0.1-7.5 keV/amu) collisions of O6+ on H2O molecules have been measured. Over the range of interaction energies the state selective cross sections change strongly, i.e., by factors up to 5, while

Electronic data capture in a rural African setting: evaluating experiences with different systems in Malawi

OpenAIRE

King, Carina; Hall, Jenny; Banda, Masford; Beard, James; Bird, Jon; Kazembe, Peter; Fottrell, Ed

2014-01-01

Background\\ud \\ud As hardware for electronic data capture (EDC), such as smartphones or tablets, becomes cheaper and more widely available, the potential for using such hardware as data capture tools in routine healthcare and research is increasing.\\ud \\ud Objective\\ud \\ud We aim to highlight the advantages and disadvantages of four EDC systems being used simultaneously in rural Malawi: two for Android devices (CommCare and ODK Collect), one for PALM and Windows OS (Pendragon), and a custom-b...

Electron-capture Isotopes Could Constrain Cosmic-Ray Propagation Models

Science.gov (United States)

Benyamin, David; Shaviv, Nir J.; Piran, Tsvi

2017-12-01

Electron capture (EC) isotopes are known to provide constraints on the low-energy behavior of cosmic rays (CRs), such as reacceleration. Here, we study the EC isotopes within the framework of the dynamic spiral-arms CR propagation model in which most of the CR sources reside in the galactic spiral arms. The model was previously used to explain the B/C and sub-Fe/Fe ratios. We show that the known inconsistency between the 49Ti/49V and 51V/51Cr ratios remains also in the spiral-arms model. On the other hand, unlike the general wisdom that says the isotope ratios depend primarily on reacceleration, we find here that the ratio also depends on the halo size (Z h) and, in spiral-arms models, also on the time since the last spiral-arm passage ({τ }{arm}). Namely, EC isotopes can, in principle, provide interesting constraints on the diffusion geometry. However, with the present uncertainties in the lab measurements of both the electron attachment rate and the fragmentation cross sections, no meaningful constraint can be placed.

Genetic effects of decay by electron capture of radionuclides in yeasts cell

International Nuclear Information System (INIS)

Gracheva, L.M.; Korolev, V.G.

1984-01-01

Regularities of genetic effect on the yeast cell Saccharomyces cerevisiae, incorporated radionuclides decaying according to the scheme of k-capture- 7 Be, 54 Mn, 85 Sr are studied. It is known that this type of decay models the ionization of internal electron shells of atoms which is most probable when a cell is affected by external ionizing radiation. It is shown that the decay of radionuclides connecting with a DNA molecule in a cell according to the scheme of D-capture brings about a strong lethal effect. The relative mutagenic efficiency is much lower than that for gamma-radiation and many radionuclides decaying according to the scheme of B-decay. In the mutation spectrum induced by these radionuclides the increase in the number of mutations of the reading frame shift type is observed

Neutrinoless double electron capture decay of 54-Fe

International Nuclear Information System (INIS)

Bikit, I; Krmar, M.; Slivka, J.; Anicin, I.; Veskovic, M.; Convie, L.

1994-01-01

Double electron capture is the only decay mode of 54-Fe to 54-Cr. The most probable KK capture in the 0 nu case would lead to an otherwise not populated excited state of 54-Cr with the energy of 668 + - KeV. This process has not been yet investigated, probably because the lacking theoretical arguments on the nature of the excited state which could favour the decay. On the other hand if we suppose that gamma transition from this state to the ground state is allowed the 668 KeV gamma ray would be a definite signature of the process. Having in mind the relatively large abundance of 54-Fe in natural iron, a large quantity of iron in some shields in low level gamma spectroscopy systems and the low and flat background in the 668 keV spectral region, we easily estimate that the sensitivity for measuring the half life of this process is quit high. With our equipment consisting of a 25% efficiency commercial HP Ge spectrometer, placed in a cubic shaped iron shield with wall thickness of 25 cm from the background spectrum measured for only 100 days we calculated the lower limit for the half life of the 0 nu EC.EC decay of 54-Fe on the 68% confidence level to be T > 3.1 *10 sup 2 sup 2 years. 2 figs., 5 refs. (author)

77 FR 11588 - Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof

Science.gov (United States)

2012-02-27

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-831] Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof AGENCY: U.S. International Trade Commission... Trade Commission on January 10, 2012, under section 337 of the Tariff Act of 1930, as amended, 19 U.S.C...

Electron capture by C2+ and Ti2+ ions in H and H2

International Nuclear Information System (INIS)

Nutt, W.L.; McCullough, R.W.; Gilbody, H.B.

1978-01-01

Cross sections for electron capture by C 2+ and Ti 2+ ions in H and H 2 have been determined within the energy range 0.5 to 14 keV from measurements made using a tungsten-tube furnace to provide a target of highly dissociated hydrogen. (author)

CDW (continuum distorted wave) type approximation for electron capture at large angles

International Nuclear Information System (INIS)

Fojon, O.A.; Maidagan, J.M.

1990-01-01

A calculation is made for the probability of electron capture in shell K at great angles using a second order symmetrical model used related to the continuum distorted wave (CDW) approximation. The influence of Coulomb distortion of nuclei is studied and compared with OBK and CIS type calculations. Numerical results are compared with experimental results of the collision of H + on C at intermediate energies. (Author). 19 refs., 2 figs

Capturing structured, pulmonary disease-specific data elements in electronic health records.

Science.gov (United States)

Gronkiewicz, Cynthia; Diamond, Edward J; French, Kim D; Christodouleas, John; Gabriel, Peter E

2015-04-01

Electronic health records (EHRs) have the potential to improve health-care quality by allowing providers to make better decisions at the point of care based on electronically aggregated data and by facilitating clinical research. These goals are easier to achieve when key, disease-specific clinical information is documented as structured data elements (SDEs) that computers can understand and process, rather than as free-text/natural-language narrative. This article reviews the benefits of capturing disease-specific SDEs. It highlights several design and implementation considerations, including the impact on efficiency and expressivity of clinical documentation and the importance of adhering to data standards when available. Pulmonary disease-specific examples of collection instruments are provided from two commonly used commercial EHRs. Future developments that can leverage SDEs to improve clinical quality and research are discussed.

A photonic crystal hydrogel suspension array for the capture of blood cells from whole blood

Science.gov (United States)

Zhang, Bin; Cai, Yunlang; Shang, Luoran; Wang, Huan; Cheng, Yao; Rong, Fei; Gu, Zhongze; Zhao, Yuanjin

2016-02-01

Diagnosing hematological disorders based on the separation and detection of cells in the patient's blood is a significant challenge. We have developed a novel barcode particle-based suspension array that can simultaneously capture and detect multiple types of blood cells. The barcode particles are polyacrylamide (PAAm) hydrogel inverse opal microcarriers with characteristic reflection peak codes that remain stable during cell capture on their surfaces. The hydrophilic PAAm hydrogel scaffolds of the barcode particles can entrap various plasma proteins to capture different cells in the blood, with little damage to captured cells.Diagnosing hematological disorders based on the separation and detection of cells in the patient's blood is a significant challenge. We have developed a novel barcode particle-based suspension array that can simultaneously capture and detect multiple types of blood cells. The barcode particles are polyacrylamide (PAAm) hydrogel inverse opal microcarriers with characteristic reflection peak codes that remain stable during cell capture on their surfaces. The hydrophilic PAAm hydrogel scaffolds of the barcode particles can entrap various plasma proteins to capture different cells in the blood, with little damage to captured cells. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06368j

Correlation between atomic negative muon capture and electron distribution in organic sp2-hybridization compounds CxHyClz

International Nuclear Information System (INIS)

Sakai, Yoichi; Tominaga, Takeshi; Ikuta, Shigeru

1986-01-01

The atomic negative muon capture ratios determined experimentally in organic sp 2 -hybridization compound, C x H y Cl z , were compared with the electron populations of carbon atomic orbitals obtained by an ab initio molecular orbital calculation in such systems. A clear positive correlation was found between the C 2s and C 2pz populations and the negative muon capture ratio A (C/Cl), suggesting the mesomolecular process in the initial stage of muon capture. (orig.)

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).

Correlation effects on double electron capture in highly-charged, low-energy ion-atom collisions

International Nuclear Information System (INIS)

Meyer, F.W.; Griffin, D.C.; Havener, C.C.; Huq, M.S.; Phaneuf, R.A.; Swenson, J.K.; Stolterfoht, N.

1987-01-01

The method of zero-degree Auger electron spectroscopy has been used to study two-electron excited states populated in slow double capture collisions of highly charged ions with He and H 2 . The focus of this study is on production of autoionization electrons originating from the non-equivalent 1s 2 2pnl electron configurations in comparison with electron production resulting from the Auger decay of (near) equivalent 1s 2 nln'l' (with n∼n') configurations. It is shown that production of non-equivalent electron configurations is significant and involves electron-electron correlation effects whose analysis leads beyond the independent-particle model. Recent results that include a measurement at non-zero angles are presented to illustrate the angular dependence of electron emission from non-equivalent electron configurations, as well as the dependence on projectile charge state and target species. Comparison of high resolution scans over two lines of the 1s 2 2pnl sequence for the O 6+ + He system with accurate transition energy calculations shows preferential population of high angular momentum substation

Electron capture in low- and intermediate-energy collisions between completely stripped light ions and metastable H(2s) targets

International Nuclear Information System (INIS)

Blanco, S.A.; Falcon, C.A.; Reinhold, C.O.; Casaubon, J.I.; Piacentini, R.D.

1987-01-01

Total cross sections for electron capture from H(2s) targets by He 2+ ions have been computed in the impact velocity range 0.05-0.5 au. Calculations were performed using a molecular close-coupling approach with inclusion of electron translation factors. A ten-state molecular basis set was considered. A comparison is made with Landau-Zener results for the same system. Intermediate projectile energy classical Monte Carlo capture cross sections are also presented for H + , He 2+ , Li 3+ and C 6+ projectiles. (author)

Statistics of electron multiplication in a multiplier phototube; Iterative method

International Nuclear Information System (INIS)

Ortiz, J. F.; Grau, A.

1985-01-01

In the present paper an iterative method is applied to study the variation of dynode response in the multiplier phototube. Three different situation are considered that correspond to the following ways of electronic incidence on the first dynode: incidence of exactly one electron, incidence of exactly r electrons and incidence of an average r electrons. The responses are given for a number of steps between 1 and 5, and for values of the multiplication factor of 2.1, 2.5, 3 and 5. We study also the variance, the skewness and the excess of jurtosis for different multiplication factors. (Author) 11 refs

Angular distributions of projectiles following electron capture from C60 by 2.5-keV Ar8+

International Nuclear Information System (INIS)

Walch, B.; Thumm, U.; Stoeckli, M.; Cocke, C.L.; Klawikowski, S.

1998-01-01

Experimental measurements of the projectile angular distributions for 2.5-keV Ar 8+ ions capturing one to five electrons from a gas-phase C 60 target are presented. The number of captured electrons was determined by demanding a coincidence between the scattered projectile and a charge-state-analyzed intact C 60 recoil ion. The results are compared to calculations based on a dynamical classical overbarrier model. Good agreement is obtained only if the influence on the projectile trajectory by the large polarizability of the C 60 target is taken into account, thereby making the collective dielectric response of the cluster target observable in a scattering experiment. copyright 1998 The American Physical Society

L-subshell resolved photon angular distribution of radiative electron capture into He-like uranium

International Nuclear Information System (INIS)

Stoehlker, T.; Geissel, H.; Irnich, H.; Kandler, T.; Kozhuharov, C.; Mokler, P.H.; Muenzenberg, G.; Nickel, F.; Scheidenberger, C.; Suzuki, T.; Kucharski, M.; Stachura, Z.; Kriessbach, A.; Shirai, T.

1994-08-01

The photon angular distributions for radiative electron capture (REC) into the j=1/2 and j=3/2 L-subshell levels were measured and calculated for U 90+ →C collisions at 89 MeV/u. The experiment provides the first study of the photon angular distribution of REC into a projectile p-state (j=3/2) which was found to exhibit a slight backward peaking in the laboratory frame. For radiative capture to the j=1/2 states the measured angular distribution deviates considerably from symmetry around 90 . The results demonstrate that the usual sin 2 θ lab distribution is not valid in the high-Z regime. (orig.)

Liquid scintillation counting efficiency in three photomultiplier systems. Pure electron capture

International Nuclear Information System (INIS)

Los Arcos, J. M.; Grau Carles, A.; Grau Malonda, A.

1990-01-01

The tables of counting efficiency as a function of the figure of merit for a liquid scintillation counting system working with three phototubes are presented. The evaluation has been carried out for a Toluene-based scintillator with 5, 10 and 15 ml column, and 19 different radionuclides decaying by pure electron capture: 37Ar 41Ca, 49V, 53 Mn, 55Fe, 59Ni, 68Ge 7iGe, 82Sr, 97Tc, 118Te, 131CS, 137La, 140Ca, 157Tb, 165Er, 193Pt, 194Hg, 205Pb. (Author) 22 refs

Nucleic acid hybridization assays employing dA-tailed capture probes. II. Advanced multiple capture methods

International Nuclear Information System (INIS)

Hunsaker, W.R.; Badri, H.; Lombardo, M.; Collins, M.L.

1989-01-01

A fourth capture is added to the reversible target capture procedure. This results in an improved radioisotopic detection limit of 7.3 x 10(-21) mol of target. In addition, the standard triple capture method is converted into a nonradioactive format with a detection limit of under 1 amol of target. The principal advantage of nonradioactive detection is that the entire assay can be performed in about 1 h. Nucleic acids are released from cells in the presence of the (capture probe) which contains a 3'-poly(dA) sequence and the (labeled probe) which contains a detectable nonradioactive moiety such as biotin. After a brief hybridization in solution, the target is captured on oligo(dT) magnetic particles. The target is further purified from sample impurities and excess labeled probe by recapture either once or twice more on fresh magnetic particles. The highly purified target is then concentrated to 200 nl by recapture onto a poly(dT) nitrocellulose filter and rapidly detected with streptavidin-alkaline phosphatase using bromochloroindolyl phosphate and nitroblue tetrazolium. Using this procedure, as little as 0.25 amol of a target plasmid has been detected nonradioactively in crude samples in just 1 h without prior purification of the DNA and RNA. Finally, a new procedure called background capture is introduced to complement the background-reducing power of RTC

Electron capture by multicharged ions at eV energies

International Nuclear Information System (INIS)

Havener, C.C.; Huq, M.S.; Meyer, F.W.; Phaneuf, R.A.

1988-01-01

A multicharged ion-atom merged-beams apparatus has been used in conjunction with the ORNL-ECR ion source to measure accurate absolute electron-capture cross sections in the energy range from below 1 eV/amu to 1500 eV/amu. Measurements for N/sup 3+,4+,5+/ /plus/ H(D) collisions indicate good agreement with available theoretical calculations. However, measurements with O 5+ /plus/ H(D) show an unexpected low-energy behavior which may be attributable to the ion-induced-dipole attraction between the reactants. Scaled Landau-Zener calculations presented here identify a transfer plus excitation channel which has the correct energy dependence at low energies. This finding suggest the need for a comprehensive coupled channel calculation which would include such product states. 25 refs., 8 figs

Comparison of Electronic Data Capture (EDC) with the Standard Data Capture Method for Clinical Trial Data

Science.gov (United States)

Walther, Brigitte; Hossin, Safayet; Townend, John; Abernethy, Neil; Parker, David; Jeffries, David

2011-01-01

Background Traditionally, clinical research studies rely on collecting data with case report forms, which are subsequently entered into a database to create electronic records. Although well established, this method is time-consuming and error-prone. This study compares four electronic data capture (EDC) methods with the conventional approach with respect to duration of data capture and accuracy. It was performed in a West African setting, where clinical trials involve data collection from urban, rural and often remote locations. Methodology/Principal Findings Three types of commonly available EDC tools were assessed in face-to-face interviews; netbook, PDA, and tablet PC. EDC performance during telephone interviews via mobile phone was evaluated as a fourth method. The Graeco Latin square study design allowed comparison of all four methods to standard paper-based recording followed by data double entry while controlling simultaneously for possible confounding factors such as interview order, interviewer and interviewee. Over a study period of three weeks the error rates decreased considerably for all EDC methods. In the last week of the study the data accuracy for the netbook (5.1%, CI95%: 3.5–7.2%) and the tablet PC (5.2%, CI95%: 3.7–7.4%) was not significantly different from the accuracy of the conventional paper-based method (3.6%, CI95%: 2.2–5.5%), but error rates for the PDA (7.9%, CI95%: 6.0–10.5%) and telephone (6.3%, CI95% 4.6–8.6%) remained significantly higher. While EDC-interviews take slightly longer, data become readily available after download, making EDC more time effective. Free text and date fields were associated with higher error rates than numerical, single select and skip fields. Conclusions EDC solutions have the potential to produce similar data accuracy compared to paper-based methods. Given the considerable reduction in the time from data collection to database lock, EDC holds the promise to reduce research-associated costs

Comparison of electronic data capture (EDC with the standard data capture method for clinical trial data.

Directory of Open Access Journals (Sweden)

Brigitte Walther

Full Text Available BACKGROUND: Traditionally, clinical research studies rely on collecting data with case report forms, which are subsequently entered into a database to create electronic records. Although well established, this method is time-consuming and error-prone. This study compares four electronic data capture (EDC methods with the conventional approach with respect to duration of data capture and accuracy. It was performed in a West African setting, where clinical trials involve data collection from urban, rural and often remote locations. METHODOLOGY/PRINCIPAL FINDINGS: Three types of commonly available EDC tools were assessed in face-to-face interviews; netbook, PDA, and tablet PC. EDC performance during telephone interviews via mobile phone was evaluated as a fourth method. The Graeco Latin square study design allowed comparison of all four methods to standard paper-based recording followed by data double entry while controlling simultaneously for possible confounding factors such as interview order, interviewer and interviewee. Over a study period of three weeks the error rates decreased considerably for all EDC methods. In the last week of the study the data accuracy for the netbook (5.1%, CI95%: 3.5-7.2% and the tablet PC (5.2%, CI95%: 3.7-7.4% was not significantly different from the accuracy of the conventional paper-based method (3.6%, CI95%: 2.2-5.5%, but error rates for the PDA (7.9%, CI95%: 6.0-10.5% and telephone (6.3%, CI95% 4.6-8.6% remained significantly higher. While EDC-interviews take slightly longer, data become readily available after download, making EDC more time effective. Free text and date fields were associated with higher error rates than numerical, single select and skip fields. CONCLUSIONS: EDC solutions have the potential to produce similar data accuracy compared to paper-based methods. Given the considerable reduction in the time from data collection to database lock, EDC holds the promise to reduce research

Identification and systematical studies of the electron-capture delayed fission (ECDF) in the lead region

CERN Multimedia

Pauwels, D B; Lane, J

2008-01-01

In our recent experiment (March 2007) at the velocity filter SHIP(GSI) we observed the electron-capture delayed fission of the odd-odd isotope $^{194}$At. This is the first unambiguous identification of this phenomenon in the very neutron-deficient nuclei in the vicinity of the proton shell closure at Z=82. In addition, the total kinetic energy (TKE) for the daughter nuclide $^{194}$Po was measured, despite the fact that this isotope does not decay via spontaneous fission. Semi-empirical analysis of the electron-capture Q$_{EC}$ values and fission barriers B$_{f}$ shows that a relatively broad island of ECDF must exist in this region of the Nuclide Chart, with some of the nuclei having unusually high ECDF probabilities. Therefore, this Proposal is intended to initiate the systematic identification and study of $\\beta$-delayed fission at ISOLDE in the very neutron-deficient lead region. Our aim is to provide unique low-energy fission data (e.g. probabilities, TKE release, fission barriers and their isospin dep...

Measurement of K-electron capture probability in the decay of [sup 87]Y

Energy Technology Data Exchange (ETDEWEB)

Prasad, N.V.S.V.; Murty, G.S.K.; Rao, M.V.S.C.; Sastry, D.L. (Andhra Univ., Visakhapatnam (India). Labs. for Nuclear Research); Chintalapudi, S.N. (Inter University Consortium for DAE Facilities, Calcutta (India))

1993-04-01

The K-electron capture probability for the 1/2[sup -] to 3/2[sup -]transition in the decay of [sup 87]Y to the 873.0 keV level in the daughter [sup 87]Sr was measured for the first time using an x-[gamma] summing method. The experimental P[sub K] value was found to be 0.911 [+-] 0.047, in agreement with the theoretical value of 0.878. (author).

Electron capture, electron loss, and deexcitation of fast H(2 2S) and H(1 2S) atoms in collisions with molecular hydrogen and inert gases

International Nuclear Information System (INIS)

Roussel, F.; Pradel, P.; Spiess, G.

1977-01-01

Collisions of ground-state (1 2 S) and metastable (2 2 S) hydrogen atoms with rare gases and molecular hydrogen have been studied in the energy range 0.5--3.0 keV. For an acceptance angle of 55 mrad, the electron loss and the electron-capture cross sections of both H(1 2 S) and H(2 2 S) have been measured and compared with previous experimental values. The deexcitation cross section for H(2 2 S) has been deduced with the help of previously measured total-quenching cross sections for H(2 2 S). The ratio of the electron-capture cross sections for H(2 2 S) relative to H(1 2 S) is found to be very large for argon at low energies. The effects of large-angle scattering and of highly excited states of H are discussed

Multiple purpose research complex on the basis of electron accelerators and terahertz free electron laser

International Nuclear Information System (INIS)

Kulipanov, G.N.

2009-01-01

In this report the basic positioning parameters of multiple purpose research complex are presented, the list of potential experiments and technological uses on the example of results received in the multiuser center of G.I. Budker Institut of nuclear physics Siberian department of the Russian Academy of Sciences is discussed. This research complex is directed on work in the big universities and nano technology centers. Electron accelerators is intended for development of electron-beam technologies different material modification, for production of nano powder, nano materials and solution of ecological tasks. In this work the project of multiple purpose research complex on the basis of new generation electron accelerator Il-14 and workable terahertz free electron laser is suggested. Terahertz free electron laser will be used for researches in the sphere of physics and chemistry, biology and medicine, nanotechnology engineering and different methods of nanodiagnostics.

K-shell x-ray production cross sections of selected elements Al to Ni for 4. 0 to 38. 0 MeV /sup 10/B ions. [Cross sections, 4. 0 to 38 MeV, binding energy, electron capture decay, PWBA, energy shifts, multiple ionization

Energy Technology Data Exchange (ETDEWEB)

Monigold, G.; McDaniel, F.D.; Duggan, J.L.; Mehta, R.; Rice, R.; Miller, P.D.

1976-01-01

K-Shell x-ray production cross sections for the target elements Sc, Ti, V, Mn, Fe, Co, and Ni were measured for incident /sup 10/B ions over the energy range 4.0 to 38.0 MeV. The cross section data were compared to the theoretical predictions of the binary encounter approximation (BEA); the plane wave born approximation (PWBA); and the PWBA modified to include corrections for increased binding energy (B), Coulomb deflection of the incident ion (C), orbital perturbation due to polarization (P), and relativistic effects (R). In addition, fluorescence yield variations (W/sub K/) and contributions to the cross sections from electron capture (EC) were included. It was found that the predictions of the fully modified PWBA with contributions from electron capture and fluorescence yield variations included provided the best fit to the experimental data over the entire energy range for each target element. The K..beta../K..cap alpha.. x-ray intensity ratios were compared to theoretical values that assume single hole ionization, and the x-ray energy shifts presented as a function of the energy of the incident ion. These two measurements provided confirmation of the occurrence of multiple ionization for /sup 10/B bombardment of target elements in the range 21 less than or equal to Z/sub 2/ less than or equal to 28.

Theory of inelastic multiphonon scattering and carrier capture by defects in semiconductors: Application to capture cross sections

Science.gov (United States)

Barmparis, Georgios D.; Puzyrev, Yevgeniy S.; Zhang, X.-G.; Pantelides, Sokrates T.

2015-12-01

Inelastic scattering and carrier capture by defects in semiconductors are the primary causes of hot-electron-mediated degradation of power devices, which holds up their commercial development. At the same time, carrier capture is a major issue in the performance of solar cells and light-emitting diodes. A theory of nonradiative (multiphonon) inelastic scattering by defects, however, is nonexistent, while the theory for carrier capture by defects has had a long and arduous history. Here we report the construction of a comprehensive theory of inelastic scattering by defects, with carrier capture being a special case. We distinguish between capture under thermal equilibrium conditions and capture under nonequilibrium conditions, e.g., in the presence of an electrical current or hot carriers where carriers undergo scattering by defects and are described by a mean free path. In the thermal-equilibrium case, capture is mediated by a nonadiabatic perturbation Hamiltonian, originally identified by Huang and Rhys and by Kubo, which is equal to linear electron-phonon coupling to first order. In the nonequilibrium case, we demonstrate that the primary capture mechanism is within the Born-Oppenheimer approximation (adiabatic transitions), with coupling to the defect potential inducing Franck-Condon electronic transitions, followed by multiphonon dissipation of the transition energy, while the nonadiabatic terms are of secondary importance (they scale with the inverse of the mass of typical atoms in the defect complex). We report first-principles density-functional-theory calculations of the capture cross section for a prototype defect using the projector-augmented wave, which allows us to employ all-electron wave functions. We adopt a Monte Carlo scheme to sample multiphonon configurations and obtain converged results. The theory and the results represent a foundation upon which to build engineering-level models for hot-electron degradation of power devices and the performance

Second-order symmetric eikonal approximation for electron capture at high energies

Energy Technology Data Exchange (ETDEWEB)

Deco, G R; Rivarola, R D [Rosario Univ. Nacional (Argentina). Dept. de Fisica

1985-06-14

A symmetric eikonal approximation for electron capture in ion-atom collisions at high energies has been developed within the Dodd and Greider (1966, Phys. Rev. 146 675) formalism. Implicit intermediate states are included through the choice of distorted initial and final wavefunctions. Explicit intermediate state are considered by the introduction of a free-particle Green's function G/sup +//sub 0/. The model is applied for the resonant charge exchange in H/sup +/+H(1s) collisions. Also, the characteristic dip of the continuum distorted-wave model is analysed when higher orders are included at 'realistic' high energies.

Multiple-electron processes in fast ion-atom collisions

International Nuclear Information System (INIS)

Schlachter, A.S.

1989-03-01

Research in atomic physics at the Lawrence Berkeley Laboratory Super-HILAC and Bevalac accelerators on multiple-electron processes in fast ion-atom collisions is described. Experiments have studied various aspects of the charge-transfer, ionization, and excitation processes. Examples of processes in which electron correlation plays a role are resonant transfer and excitation and Auger-electron emission. Processes in which electron behavior can generally be described as uncorrelated include ionization and charge transfer in high-energy ion-atom collisions. A variety of experiments and results for energies from 1 MeV/u to 420 MeV/u are presented. 20 refs., 15 figs

A new magnetic spectrometer for the investigation of the internal conversion electron in capture reaction

International Nuclear Information System (INIS)

Suarez, A.A.

1978-01-01

Planning, development and manufacture of a new beta spectrometer for the investigation of the internal conversion electrons, from 0,02 to 10 MeV, emitted during the radioative capture process of the thermal neutrons. The resolution on the base of resolution curve is about 1,5 X 10 sup(-3) [pt

Experimental study of K-electron capture probability in the decay of {sup 111}In

Energy Technology Data Exchange (ETDEWEB)

Mishra, N.R.; Kalyani, V.D.M.L.; Maldhusudhana Rao, P.V.; Vara Prasad, N.V.; Chandrasekhar Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L. [Visakhapatnam, Andhra Univ. (India). Swami Jnanananda Lab. for Nuclear Research; Chintalapudi, S.N. [Calcutt, Inter-Univ. Consortium for DAEW Facilities (India)

1998-03-01

The K-electron capture probability in the decay of {sup 111}In to the 416.64 keV level of the daughter nucleus {sup 111}Cd was measured to be 0.853 {+-}0.037 in agreement with the theoretical value 0.865. The experimental value is seen to be consistent with the mass prediction of the relationship due to Wapstra and Bos.

Evidence for correlated double-electron capture in slow collisions of multicharged ions with He and H2

International Nuclear Information System (INIS)

Meyer, F.W.; Havener, C.C.; Phaneuf, R.A.; Swenson, J.K.; Shafroth, S.M.; Stolterfoht, N.

1986-01-01

High resolution measurements of the production of L 1 L 23 M Coster-Kronig and LMM-Auger electrons in slow collisions of C 4+ , N 5+ , O 6+ , and 0 7+ with He and H 2 have been performed, using the method of 0 0 Auger spectroscopy. For the latter three projectiles, strong Coster Kronig lines are observed, which are attributed to the configurations (core)2pnl, produced by double-electron capture. It is argued that production of these nonequivalent electron configurations must involve electron-electron correlation. From a comparison of the production cross sections for these Coster-Kronig electrons and the LMM-Auger electrons, it is further argued the correlation plays a significant role in two-electron transfer processes. 7 refs., 5 figs

Measurement on K-electron capture probability in the decay of 97Ru

International Nuclear Information System (INIS)

Kalayani, V.D.M.L.; Vara Prasad, N.V.S.; Chandrasekhar Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L.; Chintalapudi, S.N.

1999-01-01

The K-electron capture probabilities of two strong allowed transitions 5/2 + →5/2 + and 5/2 + →7/2 + were measured in the decay of 97 Ru employing the X-γ internal summing technique. The two P K experimental values were found to be 0.884±0.046 and 0.886±0.018 in agreement with the theoretical values 0.878 and 0.878, respectively. The theoretical values are seen to be insensitive for Q EC values above 200 keV

ELECTRON-CAPTURE AND β-DECAY RATES FOR sd-SHELL NUCLEI IN STELLAR ENVIRONMENTS RELEVANT TO HIGH-DENSITY O–NE–MG CORES

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Toshio [Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, Nihon University Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan); Toki, Hiroshi [Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047 (Japan); Nomoto, Ken’ichi, E-mail: suzuki@phys.chs.nihon-u.ac.jp [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)

2016-02-01

Electron-capture and β-decay rates for nuclear pairs in the sd-shell are evaluated at high densities and high temperatures relevant to the final evolution of electron-degenerate O–Ne–Mg cores of stars with initial masses of 8–10 M{sub ⊙}. Electron capture induces a rapid contraction of the electron-degenerate O–Ne–Mg core. The outcome of rapid contraction depends on the evolutionary changes in the central density and temperature, which are determined by the competing processes of contraction, cooling, and heating. The fate of the stars is determined by these competitions, whether they end up with electron-capture supernovae or Fe core-collapse supernovae. Since the competing processes are induced by electron capture and β-decay, the accurate weak rates are crucially important. The rates are obtained for pairs with A = 20, 23, 24, 25, and 27 by shell-model calculations in the sd-shell with the USDB Hamiltonian. Effects of Coulomb corrections on the rates are evaluated. The rates for pairs with A = 23 and 25 are important for nuclear Urca processes that determine the cooling rate of the O–Ne–Mg core, while those for pairs with A = 20 and 24 are important for the core contraction and heat generation rates in the core. We provide these nuclear rates at stellar environments in tables with fine enough meshes at various densities and temperatures for studies of astrophysical processes sensitive to the rates. In particular, the accurate rate tables are crucially important for the final fates of not only O–Ne–Mg cores but also a wider range of stars, such as C–O cores of lower-mass stars.

ELECTRON-CAPTURE AND β-DECAY RATES FOR sd-SHELL NUCLEI IN STELLAR ENVIRONMENTS RELEVANT TO HIGH-DENSITY O–NE–MG CORES

International Nuclear Information System (INIS)

Suzuki, Toshio; Toki, Hiroshi; Nomoto, Ken’ichi

2016-01-01

Electron-capture and β-decay rates for nuclear pairs in the sd-shell are evaluated at high densities and high temperatures relevant to the final evolution of electron-degenerate O–Ne–Mg cores of stars with initial masses of 8–10 M ⊙ . Electron capture induces a rapid contraction of the electron-degenerate O–Ne–Mg core. The outcome of rapid contraction depends on the evolutionary changes in the central density and temperature, which are determined by the competing processes of contraction, cooling, and heating. The fate of the stars is determined by these competitions, whether they end up with electron-capture supernovae or Fe core-collapse supernovae. Since the competing processes are induced by electron capture and β-decay, the accurate weak rates are crucially important. The rates are obtained for pairs with A = 20, 23, 24, 25, and 27 by shell-model calculations in the sd-shell with the USDB Hamiltonian. Effects of Coulomb corrections on the rates are evaluated. The rates for pairs with A = 23 and 25 are important for nuclear Urca processes that determine the cooling rate of the O–Ne–Mg core, while those for pairs with A = 20 and 24 are important for the core contraction and heat generation rates in the core. We provide these nuclear rates at stellar environments in tables with fine enough meshes at various densities and temperatures for studies of astrophysical processes sensitive to the rates. In particular, the accurate rate tables are crucially important for the final fates of not only O–Ne–Mg cores but also a wider range of stars, such as C–O cores of lower-mass stars

Distinguishing of Ile/Leu amino acid residues in the PP3 protein by (hot) electron capture dissociation in Fourier transform ion cyclotron resonance mass spectrometry

DEFF Research Database (Denmark)

Kjeldsen, Frank; Haselmann, Kim F; Sørensen, Esben Skipper

2003-01-01

In hot electron capture dissociation (HECD), multiply protonated polypeptides fragment upon capturing approximately 11-eV electrons. The excess of energy upon the primary c, z* cleavage induces secondary fragmentation in z* fragments. The resultant w ions allow one to distinguish between the isom...

Electron capture and excitation in collisions of O+(4S,2D,2P) with H2 molecules

International Nuclear Information System (INIS)

Pichl, Lukas; Li Yan; Liebermann, Heinz-Peter; Buenker, Robert J.; Kimura, Mineo

2004-01-01

Using an electronic-state close-coupling method, we treated the electron capture and excitation processes of O + ions both in ground state O + ( 4 S) and metastable states O +* ( 2 D) and O +* ( 2 P) in collisions with the H 2 molecule. In the ground-state projectile energy region considered (from 50 eV/amu to 10 keV/amu), the experimental data vary by orders of magnitude: our results smoothly connect to the data by Flesch and Ng [J. Chem. Phys. 94, 2372 (1991)] and Xu et al. [J. Phys. B 23, 1235 (1990)] at low energy and agree with Phaneuf et al. [Phys. Rev. A 17, 534 (1978)] in the high-energy region. The present values differ from Sieglaff et al. [Phys. Rev. A 59, 3538 (1999)] and Nutt et al. [J. Phys. B 12, L157 (1979)], especially in the energy region below 1 keV/amu. We provide the first calculated state-resolved cross sections of electron capture and target-projectile electronic excitations for the O + ( 4 S, 2 D, 2 P)-H 2 collision system

COINCIDENCES BETWEEN ELECTRONS AND TARGET IONS TO IDENTIFY CAPTURE CHANNELS IN COLLISIONS OF MULTIPLY CHARGED IONS ON GAS TARGETS

NARCIS (Netherlands)

POSTHUMUS, JH; MORGENSTERN, R

1992-01-01

We have investigated multielectron capture processes in collisions of Ar9+ on Ar by measuring the resulting Auger electrons in coincidence with charge-state-analyzed target ions. In this way it was possible to reconstruct partial electron energy spectra, each corresponding to a particular number of

Observation of laser multiple filamentation process and multiple electron beams acceleration in a laser wakefield accelerator

International Nuclear Information System (INIS)

Li, Wentao; Liu, Jiansheng; Wang, Wentao; Chen, Qiang; Zhang, Hui; Tian, Ye; Zhang, Zhijun; Qi, Rong; Wang, Cheng; Leng, Yuxin; Li, Ruxin; Xu, Zhizhan

2013-01-01

The multiple filaments formation process in the laser wakefield accelerator (LWFA) was observed by imaging the transmitted laser beam after propagating in the plasma of different density. During propagation, the laser first self-focused into a single filament. After that, it began to defocus with energy spreading in the transverse direction. Two filaments then formed from it and began to propagate independently, moving away from each other. We have also demonstrated that the laser multiple filamentation would lead to the multiple electron beams acceleration in the LWFA via ionization-induced injection scheme. Besides, its influences on the accelerated electron beams were also analyzed both in the single-stage LWFA and cascaded LWFA

Radiative electron capture studied in relativistic heavy-ion--atom collisions

International Nuclear Information System (INIS)

Stoehlker, T.; Kozhuharov, C.; Mokler, P.H.; Warczak, A.; Bosch, F.; Geissel, H.; Moshammer, R.; Scheidenberger, C.; Eichler, J.; Ichihara, A.; Shirai, T.; Stachura, Z.; Rymuza, P.

1995-01-01

The process of radiative electron capture (REC) in relativistic collisions of high-Z ions with low-Z gaseous and solid targets is studied experimentally and theoretically. The observed x-ray spectra are analyzed with respect to photon angular distributions as well as to total K-REC cross sections. The experimental results for angle-differential cross sections are well reproduced by exact relativistic calculations which yield significant deviations from standard sin 2 θ distributions. Total cross sections for K-REC are shown to follow a simple scaling rule obtained from exact relativistic calculations as well as from a nonrelativistic dipole approximation. The agreement between these different theoretical approaches must be regarded as fortuitous, but it lends support to the use of the nonrelativistic approach for practical purposes

Physics Reach with a Monochromatic Neutrino Beam from Electron Capture

CERN Document Server

Bernabeu, J.; Espinoza, C.; Lindroos, M.

2005-01-01

Neutrino oscillation experiments from different sources have demonstrated non-vanishing neutrino masses and flavour mixings. The next experiments have to address the determination of the connecting mixing U(e3) and the existence of the CP violating phase. Whereas U(e3) measures the strength of the oscillation probability in appearance experiments, the CP phase acts as a phase-shift in the interference pattern. Here we propose to separate these two parameters by energy dependence, using the novel idea of a monochromatic neutrino beam facility based on the acceleration of ions that decay fast through electron capture. Fine tuning of the boosted neutrino energy allows precision measurements able to open a window for the discovery of CP violation, even for a mixing as small as 1 degree

Continuum multiple-scattering approach to electron-molecule scattering and molecular photoionization

International Nuclear Information System (INIS)

Dehmer, J.L.; Dill, D.

1979-01-01

The multiple-scattering approach to the electronic continuum of molecules is described. The continuum multiple-scattering model (CMSM) was developed as a survey tool and, as such was required to satisfy two requirements. First, it had to have a very broad scope, which means (i) molecules of arbitrary geometry and complexity containing any atom in the periodic system, (ii) continuum electron energies from 0-1000 eV, and (iii) capability to treat a large range of processes involving both photoionization and electron scattering. Second, the structure of the theory was required to lend itself to transparent, physical interpretation of major spectral features such as shape resonances. A comprehensive theoretical framework for the continuum multiple scattering method is presented, as well as its applications to electron-molecule scattering and molecular photoionization. Highlights of recent applications in these two areas are reviewed. The major impact of the resulting studies over the last few years has been to establish the importance of shape resonances in electron collisions and photoionization of practically all (non-hydride) molecules

Comparison of quantification methods for the analysis of polychlorinated alkanes using electron capture negative ionization mass spectrometry.

NARCIS (Netherlands)

Rusina, T.; Korytar, P.; de Boer, J.

2011-01-01

Four quantification methods for short-chain chlorinated paraffins (SCCPs) or polychlorinated alkanes (PCAs) using gas chromatography electron capture negative ionisation low resolution mass spectrometry (GC-ECNI-LRMS) were investigated. The method based on visual comparison of congener group

Comparison of quantification methods for the analysis of polychlorinated alkanes using electron capture negative ionisation mass spectrometry

NARCIS (Netherlands)

Rusina, T.; Korytar, P.; Boer, de J.

2011-01-01

Four quantification methods for short-chain chlorinated paraffins (SCCPs) or polychlorinated alkanes (PCAs) using gas chromatography electron capture negative ionisation low resolution mass spectrometry (GC-ECNI-LRMS) were investigated. The method based on visual comparison of congener group

Dipole and Coulomb forces in electron capture dissociation and electron transfer dissociation mass spectroscopy.

Science.gov (United States)

Świerszcz, Iwona; Skurski, Piotr; Simons, Jack

2012-02-23

Ab initio electronic structure calculations were performed on a doubly charged polypeptide model H(+)-Lys(Ala)(19)-CO-CH(NH(2))-CH(2)-SS-CH(2)-(NH(2))CH-CO-(Ala)(19)-Lys-H(+) consisting of a C-terminal protonated Lys followed by a 19-Ala α-helix with a 20th Ala-like unit whose side chain is linked by a disulfide bond to a corresponding Ala-like unit connected to a second 19-Ala α-helix terminated by a second C-terminal-protonated Lys. The Coulomb potentials arising from the two charged Lys residues and dipole potentials arising from the two oppositely directed 72 D dipoles of the α-helices act to stabilize the SS bond's σ* orbital. The Coulomb potentials provide stabilization of 1 eV, while the two large dipoles generate an additional 4 eV. Such stabilization allows the SS σ* orbital to attach an electron and thereby generate disulfide bond cleavage products. Although calculations are performed only on SS bond cleavage, discussion of N-C(α) bond cleavage caused by electron attachment to amide π* orbitals is also presented. The magnitudes of the stabilization energies as well as the fact that they arise from Coulomb and dipole potentials are supported by results on a small model system consisting of a H(3)C-SS-CH(3) molecule with positive and negative fractional point charges to its left and right designed to represent (i) two positive charges ca. 32 Å distant (i.e., the two charged Lys sites of the peptide model) and (ii) two 72 D dipoles (i.e., the two α-helices). Earlier workers suggested that internal dipole forces in polypeptides could act to guide incoming free electrons (i.e., in electron capture dissociation (ECD)) toward the positive end of the dipole and thus affect the branching ratios for cleaving various bonds. Those workers argued that, because of the huge mass difference between an anion donor and a free electron, internal dipole forces would have a far smaller influence over the trajectory of a donor (i.e., in electron transfer dissociation

Electron capture by Ne3+ ions from atomic hydrogen

International Nuclear Information System (INIS)

Rejoub, R.; Bannister, M.E.; Havener, C.C.; Savin, D.W.; Verzani, C.J.; Wang, J.G.; Stancil, P.C.

2004-01-01

Using the Oak Ridge National Laboratory ion-atom merged-beam apparatus, absolute total electron-capture cross sections have been measured for collisions of Ne 3+ ions with hydrogen (deuterium) atoms at energies between 0.07 and 826 eV/u. Comparison to previous measurements shows large discrepancies between 50 and 400 eV/u. Previously published molecular-orbital close-coupling (MOCC) calculations were performed over limited energy ranges, but show good agreement with the present measurements. Here MOCC calculations are presented for energies between 0.01 and 1000 eV/u for collisions with both H and D. For energies below ∼1 eV/u, an enhancement in the magnitude of both the experimental and theoretical cross sections is observed which is attributed to the ion-induced dipole attraction between the reactants. Below ∼4 eV/u, the present calculations show a significant target isotope effect

Electron capture by Ne3+ ions from atomic hydrogen

Science.gov (United States)

Rejoub, R.; Bannister, M. E.; Havener, C. C.; Savin, D. W.; Verzani, C. J.; Wang, J. G.; Stancil, P. C.

2004-05-01

Using the Oak Ridge National Laboratory ion-atom merged-beam apparatus, absolute total electron-capture cross sections have been measured for collisions of Ne3+ ions with hydrogen (deuterium) atoms at energies between 0.07 and 826 eV/u . Comparison to previous measurements shows large discrepancies between 50 and 400 eV/u . Previously published molecular-orbital close-coupling (MOCC) calculations were performed over limited energy ranges, but show good agreement with the present measurements. Here MOCC calculations are presented for energies between 0.01 and 1000 eV/u for collisions with both H and D. For energies below ˜1 eV/u , an enhancement in the magnitude of both the experimental and theoretical cross sections is observed which is attributed to the ion-induced dipole attraction between the reactants. Below ˜4 eV/u , the present calculations show a significant target isotope effect.

Radiative electron capture studied in relativistic heavy-ion atom collisions

International Nuclear Information System (INIS)

Stoehlker, T.; Kozhuharov, C.; Mokler, P.H.; Warczak, A.; Bosch, F.; Geissel, H.; Moshammer, R.; Scheidenberger, C.; Eichler, J.; Shirai, T.; Stachura, Z.; Rymuza, P.

1994-08-01

The process of Radiative Electron Capture (REC) in relativistic collisions of high-Z ions with low-Z gaseous and solid targets is studied experimentally and theoretically. The observed X-ray spectra are analysed with respect to photon angular distributions as well as to total K-REC cross sections. The experimental results for angle-differential cross sections are well-reproduced by exact relativistic calculations which yield significant deviations from standard sin 2 θ distributions. Total cross sections for K-REC are shown to follow a simple scaling rule obtained from exact relativistic calculations as well as from a non-relativistic dipole approximation. The agreement between these different theoretical approaches must be regarded as fortuitous, but it lends support to the use of the non-relativistic approach for practical purposes. (orig.)

Enhanced electron capture by fast heavy di-clusters exciting solids

International Nuclear Information System (INIS)

Cooney, P.J.; Faibis, A.; Kanter, E.P.; Koenig, W.; Maor, D.; Zabransky, B.J.

1985-01-01

The authors have studied the dependence of the charge-state-distributions of heavy-ion fragments resulting from the foil-induced dissociation of 4.2-MeV N 2 + ions on the thickness of the carbon target foil. The results were compared to those distributions measured for impact of 2.1-MeV N + projectiles. Whereas the charge-state distributions for atomic ion impact are already equilibrated in the thinnest targets used (2 μg/cm 2 ), those measured for molecular ion impact are strongly dependent on the target thickness, even for the thickest targets (100 + g/cm 2 ). The distributions for molecular-ion impact show a marked shift towards lower charge states, evidencing an enhanced electron capture probability over the case of monatomic ion impact. A quantitative model was developed to explain this phenomenon

Precision electron-capture energy in {sup 202}Pb and its relevance for neutrino mass determination

Energy Technology Data Exchange (ETDEWEB)

Welker, A. [CERN, Geneva (Switzerland); Technische Universitaet Dresden, Dresden (Germany); Filianin, P. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Althubiti, N.A.S. [The University of Manchester, School of Physics and Astronomy, Manchester (United Kingdom); Atanasov, D.; Blaum, K.; Eliseev, S.; Kreim, S. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Cocolios, T.E. [The University of Manchester, School of Physics and Astronomy, Manchester (United Kingdom); KU Leuven, Instituut voor Kern- en Stralingsfysica, Leuven (Belgium); Herfurth, F.; Neidherr, D. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Lunney, D. [CSNSM-IN2P3-CNRS, Universite Paris-Sud, Orsay (France); Manea, V. [CERN, Geneva (Switzerland); Novikov, Yu. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Physics Faculty, St. Petersburg State University (Russian Federation); Rosenbusch, M.; Schweikhard, L.; Wienholtz, F. [Ernst-Moritz-Arndt-Universitaet, Institut fuer Physik, Greifswald (Germany); Wolf, R.N. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); The University of Sydney, ARC Centre of Excellence for Engineered Quantum Systems, Sydney (Australia); Zuber, K. [Technische Universitaet Dresden, Dresden (Germany)

2017-07-15

Within the framework of an extensive programme devoted to the search for alternative candidates for the neutrino mass determination, the atomic mass difference between {sup 202}Pb and {sup 202}Tl has been measured with the Penning trap mass spectrometer ISOLTRAP at the ISOLDE facility at CERN. The obtained value Q{sub EC} = 38.8(43) keV is three times more precise than the AME2012 value. While it will probably not lead to a replacement of {sup 163}Ho in modern experiments on the determination of the electron-neutrino mass, the electron capture in {sup 202}Pb would however allow a determination of the electron-neutrino mass on the few-eV level using a cryogenic micro-calorimeter. (orig.)

Electron-capture Rates for pf-shell Nuclei in Stellar Environments and Nucleosynthesis

Science.gov (United States)

Suzuki, Toshio; Honma, Michio; Mori, Kanji; Famiano, Michael A.; Kajino, Toshitaka; Hidakai, Jun; Otsuka, Takaharu

Gamow-Teller strengths in pf-shell nuclei obtained by a new shell-model Hamltonian, GXPF1J, are used to evaluate electron-capture rates in pf-shell nuclei at stellar environments. The nuclear weak rates with GXPF1J, which are generally smaller than previous evaluations for proton-rich nuclei, are applied to nucleosynthesis in type Ia supernova explosions. The updated rates are found to lead to less production of neutron-rich nuclei such as 58Ni and 54Cr, thus toward a solution of the problem of over-production of neutron-rich isotopes of iron-group nuclei compared to the solar abundance.

Resonant Electron capture for be-like ions with K- and L- shell excitations

International Nuclear Information System (INIS)

Hanafy, H.

2005-01-01

Resonant electron capture in electron-ion collisions is known as dielectronic recombination (DR). It was proved that, DR dominants usually over radiative recombination (RR) at high energy. Since 1980's, DR is considered a very important process in thermal plasma. The DR is an effective process in self-cooling and ionization balance as well as plasma modeling. Experimental works are still carried out to understand the trends of DR process. In the present work, DR cross sections are calculated for Be-like ions with K- and L- shell excitations. It is found that, DR cross sections increase as the effective charge (Zeff) increases for both types of excitations. DR rates coefficient in case of L-shell excitation is found to be five times larger than that of K-shell excitation

Analysis of neonicotinoids by gas chromatography coupled to nuclide 63Ni - Electron Capture Detector - GC/ECD

International Nuclear Information System (INIS)

Amaral, Priscila O.; Leao, Claudio; Redigolo, Marcelo M.; Crepaldi, Caike; Bustillos, Oscar V.

2015-01-01

Recently, several reports have been published discussing reduction in bee population which polymerizes cultures around the world this phenomenon is known as Colony Collapse Disorder (CCD). The phenomenon describes the lack of worker honeybees in the colony despite having pups and food. The causes of this problem are unknown but there are studies that claim that reduction of population of bees is linked to poisoning through insecticides specifically neonicotinoids. Among this type of pesticide are imidacloprid (C 9 H 10 ClN 5 O 2 ), clothianidin (C 6 H 8 ClN 5 O 2 S) and thiamethoxam (C 8 H 10 ClN 5 O 3 S). This paper presents the analysis of neonicotinoids - clothianidin, imidacloprid and thiamethoxam - by the technique of gas chromatography coupled to nuclide 63 Ni electron capture detector (GC/ECD). The electron capture detector (ECD) is a gas chromatography detector that has been used for the detection of organic halogens, nitriles, nitrates and organometallic compounds. The ECD detector ionizes the analytes by the beta particles from the nuclide sources 63 Ni within carrier gas N 2 . The electrons produced in this process are collected and create a current that are amplified and generates a chromatographic peak. Methodology and details of the analysis are present in this work. (author)

Relative K-electron capture probabilities in the decay of 99Rh

International Nuclear Information System (INIS)

Mishra, N.R.; Chandrasekhar Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L.; Chintalapudi, S.N.

2000-01-01

The relative K-electron capture probabilities (P K ) to the 1383.23, 896.98, 618.09, 442.78 and 322.43 keV levels in 99 Ru in the decay of 99 Rh are measured employing the X-γ internal sum-coincidence technique. The measured values P K 1383.23=0.851±0.066, P K 896.98=0.834±0.061, P K 618.09=0.870±0.01, P K 442.78=0.882±0.035 and P K 322.43=0.852±0.061 are found to be in good agreement with the theoretical values. The dependence of P K on EC transition energy is discussed. (author)

Influence of the Coulomb interaction in the final state on the cross section of single-electron capture by fast ions

International Nuclear Information System (INIS)

Novikov, N.V.; Teplova, Ya.A.

2011-01-01

It is shown that the Coulomb interaction of ions in the final state must be taken into account in the estimation of the cross section of electron capture by fast ions. The cross section of electron capture decreases considerably, and the dependence of the cross section on the collision energy becomes close to the experimental one if the interaction of charged particles after collision is taken into account. -- Highlights: → Coulomb interaction of ions in the final state must be taken into account. → This interaction leads to a considerable decrease in the cross section. → The dependence on energy close to the experimental one.

Single electron capture measurements in collisions of K{sup +} on N{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Alarcón, F.B. [Laboratorio de Espectroscopia, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Fuentes, B.E., E-mail: beatriz.fuentes@ciencias.unam.mx [Facultad de Ciencias, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, 04510 México D.F. (Mexico); Martínez, H. [Laboratorio de Espectroscopia, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62210 Cuernavaca, Morelos (Mexico); Yousif, F.B. [Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Av. Universidad #1000, Col. Chamilpa, C.P. 62210, Cuernavaca, Morelos (Mexico)

2014-08-01

Absolute total charge transfer cross sections have been measured for K{sup +}–N{sub 2} collisions, at impact energies between 1.0 and 3.5 keV. The charge transfer cross sections show a monotonic increasing behaviour as a function of the incident energy. Agreement with other groups is observed as the present measurements extend to lower energies. A semi-empirical calculation shows a similar behaviour to the present data with respect to the electron capture cross sections as a function of energy.

Probing Protein Structure and Folding in the Gas Phase by Electron Capture Dissociation

Science.gov (United States)

Schennach, Moritz; Breuker, Kathrin

2015-07-01

The established methods for the study of atom-detailed protein structure in the condensed phases, X-ray crystallography and nuclear magnetic resonance spectroscopy, have recently been complemented by new techniques by which nearly or fully desolvated protein structures are probed in gas-phase experiments. Electron capture dissociation (ECD) is unique among these as it provides residue-specific, although indirect, structural information. In this Critical Insight article, we discuss the development of ECD for the structural probing of gaseous protein ions, its potential, and limitations.

Behavioral changes induced by single and multiple electron beam pulses

International Nuclear Information System (INIS)

Pease, V.P.; McNulty, P.J.

1985-01-01

The effects of single, and low-dose, high-dose-rate and multiple electron beam pulses on passive avoidance behavior in mice were studied. Passive avoidance was measured by recording the time that an animal took to enter a chamber from a narrow platform. There were four conditions in the experiment: (1) no shock no radiation-control, (2) radiation only, (3) shock only, and (4) radiation plus shock. Forty animals were run for each data point. Dose rate was held constant at 9 x 10/sup 7/ rads/sec. Average doses for the two single pulses were 7.18 and 8.72 rads. The average total dose for a 25 pulse per second condition was 324.0 rads. The differences between the single versus multiple pulse radiation-only conditions were significant with longer avoidance latencies in the multiple pulse condition. Avoidance latencies were also significantly longer in the shock plus radiation condition for the multiple beam pulse than the single pulse. It is concluded that single and multiple electron beam pulses significantly effect behavior, in this case producing avoidance

IMAGE CAPTURE WITH SYNCHRONIZED MULTIPLE-CAMERAS FOR EXTRACTION OF ACCURATE GEOMETRIES

Directory of Open Access Journals (Sweden)

M. Koehl

2016-06-01

Full Text Available This paper presents a project of recording and modelling tunnels, traffic circles and roads from multiple sensors. The aim is the representation and the accurate 3D modelling of a selection of road infrastructures as dense point clouds in order to extract profiles and metrics from it. Indeed, these models will be used for the sizing of infrastructures in order to simulate exceptional convoy truck routes. The objective is to extract directly from the point clouds the heights, widths and lengths of bridges and tunnels, the diameter of gyrating and to highlight potential obstacles for a convoy. Light, mobile and fast acquisition approaches based on images and videos from a set of synchronized sensors have been tested in order to obtain useable point clouds. The presented solution is based on a combination of multiple low-cost cameras designed on an on-boarded device allowing dynamic captures. The experimental device containing GoPro Hero4 cameras has been set up and used for tests in static or mobile acquisitions. That way, various configurations have been tested by using multiple synchronized cameras. These configurations are discussed in order to highlight the best operational configuration according to the shape of the acquired objects. As the precise calibration of each sensor and its optics are major factors in the process of creation of accurate dense point clouds, and in order to reach the best quality available from such cameras, the estimation of the internal parameters of fisheye lenses of the cameras has been processed. Reference measures were also realized by using a 3D TLS (Faro Focus 3D to allow the accuracy assessment.

Image Capture with Synchronized Multiple-Cameras for Extraction of Accurate Geometries

Science.gov (United States)

Koehl, M.; Delacourt, T.; Boutry, C.

2016-06-01

This paper presents a project of recording and modelling tunnels, traffic circles and roads from multiple sensors. The aim is the representation and the accurate 3D modelling of a selection of road infrastructures as dense point clouds in order to extract profiles and metrics from it. Indeed, these models will be used for the sizing of infrastructures in order to simulate exceptional convoy truck routes. The objective is to extract directly from the point clouds the heights, widths and lengths of bridges and tunnels, the diameter of gyrating and to highlight potential obstacles for a convoy. Light, mobile and fast acquisition approaches based on images and videos from a set of synchronized sensors have been tested in order to obtain useable point clouds. The presented solution is based on a combination of multiple low-cost cameras designed on an on-boarded device allowing dynamic captures. The experimental device containing GoPro Hero4 cameras has been set up and used for tests in static or mobile acquisitions. That way, various configurations have been tested by using multiple synchronized cameras. These configurations are discussed in order to highlight the best operational configuration according to the shape of the acquired objects. As the precise calibration of each sensor and its optics are major factors in the process of creation of accurate dense point clouds, and in order to reach the best quality available from such cameras, the estimation of the internal parameters of fisheye lenses of the cameras has been processed. Reference measures were also realized by using a 3D TLS (Faro Focus 3D) to allow the accuracy assessment.

Measurement on K-electron capture probability in the decay of {sup 97}Ru

Energy Technology Data Exchange (ETDEWEB)

Kalayani, V.D.M.L.; Vara Prasad, N.V.S.; Chandrasekhar Rao, M.V.S.; Satyanarayana, G.; Sastry, D.L. [Swami Jnanananda Laboratories for Nuclear Research, Andhra University, Visakhapatnam (India); Chintalapudi, S.N. [Inter University Consortium for DEA Facililities, Calcutta (India)

1999-08-01

The K-electron capture probabilities of two strong allowed transitions 5/2{sup +}{yields}5/2{sup +} and 5/2{sup +}{yields}7/2{sup +} were measured in the decay of {sup 97}Ru employing the X-{gamma} internal summing technique. The two P{sub K} experimental values were found to be 0.884{+-}0.046 and 0.886{+-}0.018 in agreement with the theoretical values 0.878 and 0.878, respectively. The theoretical values are seen to be insensitive for Q{sub EC} values above 200 keV.

Management of radioactive waste gases from PET radiopharmaceutical synthesis using cost effective capture systems integrated with a cyclotron safety system.

Science.gov (United States)

Stimson, D H R; Pringle, A J; Maillet, D; King, A R; Nevin, S T; Venkatachalam, T K; Reutens, D C; Bhalla, R

2016-09-01

The emphasis on the reduction of gaseous radioactive effluent associated with PET radiochemistry laboratories has increased. Various radioactive gas capture strategies have been employed historically including expensive automated compression systems. We have implemented a new cost-effective strategy employing gas capture bags with electronic feedback that are integrated with the cyclotron safety system. Our strategy is suitable for multiple automated 18 F radiosynthesis modules and individual automated 11 C radiosynthesis modules. We describe novel gas capture systems that minimize the risk of human error and are routinely used in our facility.

Harvesting multiple electron-hole pairs generated through plasmonic excitation of Au nanoparticles.

Science.gov (United States)

Kim, Youngsoo; Smith, Jeremy G; Jain, Prashant K

2018-05-07

Multi-electron redox reactions, although central to artificial photosynthesis, are kinetically sluggish. Amidst the search for synthetic catalysts for such processes, plasmonic nanoparticles have been found to catalyse multi-electron reduction of CO 2 under visible light. This example motivates the need for a general, insight-driven framework for plasmonic catalysis of such multi-electron chemistry. Here, we elucidate the principles underlying the extraction of multiple redox equivalents from a plasmonic photocatalyst. We measure the kinetics of electron harvesting from a gold nanoparticle photocatalyst as a function of photon flux. Our measurements, supported by theoretical modelling, reveal a regime where two-electron transfer from the excited gold nanoparticle becomes prevalent. Multiple electron harvesting becomes possible under continuous-wave, visible-light excitation of moderate intensity due to strong interband transitions in gold and electron-hole separation accomplished using a hole scavenger. These insights will help expand the utility of plasmonic photocatalysis beyond CO 2 reduction to other challenging multi-electron, multi-proton transformations such as N 2 fixation.

One-electron capture and target ionization in He+-neutral-atom collisions

International Nuclear Information System (INIS)

Shevelko, V.P.; Tolstikhina, I.Yu.; Kato, D.; Tawara, H.; Song, M-.Y.; Yoon, J-.S.

2009-12-01

One-electron capture and target-ionization cross sections in collisions of He + ions with neutral atoms: He + + A → He + A + and He + + A → He + + A + + e, A = H, He(1s 2 , 1s2s), Ne, Ar, Kr, Xe, are calculated and compared with available experimental data over the broad energy range E = 0.1 keV/u - 10 MeV/u of He + ions. The role of the metastable states of neutral helium atoms in such collisions, which are of importance in plasma physics applications, is briefly discussed. The recommended cross section data for these processes are presented in a closed analytical form (nine-order polynomials) which can be used for a plasma modeling and diagnostics. (author)

Shifts in electron capture to the continuum at low collision energies: Enhanced role of target postcollision interactions

International Nuclear Information System (INIS)

Shah, M. B.; McGrath, C.; Luna, H.; Crothers, D.S.F.; O'Rourke, S.F.C.; Gilbody, H.B.; Illescas, Clara; Riera, A.; Pons, B.

2003-01-01

Measurements of electron velocity distributions emitted at 0 deg. for collisions of 10- and 20-keV H + incident ions on H 2 and He show that the electron capture to the continuum cusp formation, which is still possible at these low impact energies, is shifted to lower momenta than its standard position (centered on the projectile velocity), as recently predicted. Classical trajectory Monte Carlo calculations reproduce the observations remarkably well, and indicate that a long-range residual interaction of the electron with the target ion after ionization is responsible for the shifts, which is a general effect that is enhanced at low nuclear velocities

Interlayer electron-hole pair multiplication by hot carriers in atomic layer semiconductor heterostructures

Science.gov (United States)

Barati, Fatemeh; Grossnickle, Max; Su, Shanshan; Lake, Roger; Aji, Vivek; Gabor, Nathaniel

Two-dimensional heterostructures composed of atomically thin transition metal dichalcogenides provide the opportunity to design novel devices for the study of electron-hole pair multiplication. We report on highly efficient multiplication of interlayer electron-hole pairs at the interface of a tungsten diselenide / molybdenum diselenide heterostructure. Electronic transport measurements of the interlayer current-voltage characteristics indicate that layer-indirect electron-hole pairs are generated by hot electron impact excitation. Our findings, which demonstrate an efficient energy relaxation pathway that competes with electron thermalization losses, make 2D semiconductor heterostructures viable for a new class of hot-carrier energy harvesting devices that exploit layer-indirect electron-hole excitations. SHINES, an Energy Frontier Research Center funded by the U.S. Department of Energy, Air Force Office of Scientific Research.

Multiple choice questions in electronics and electrical engineering

CERN Document Server

DAVIES, T J

2013-01-01

A unique compendium of over 2000 multiple choice questions for students of electronics and electrical engineering. This book is designed for the following City and Guilds courses: 2010, 2240, 2320, 2360. It can also be used as a resource for practice questions for any vocational course.

Radiative electron capture into the K-, L-, and M-shell of decelerated, hydrogenic Ge projectiles

International Nuclear Information System (INIS)

Stoehlker, T.; Kozhuharov, C.; Livingston, A.E.; Mokler, P.H.; Stachura, Z.; Warczak, A.

1991-12-01

Radiative Electron Capture (REC) in 4 to 12 MeV/u Ge 31+ →H 2 collisions has been studied using an X-ray/particle coincidence technique. This technique allowed a systematic investigation of K-shell REC as well as a separation of REC into the projectile L- and M-shells. The cross sections are discussed within a general scaling picture based on the reduced projectile velocity. (orig.)

Electron transfer, ionization, and excitation atomic collisions

International Nuclear Information System (INIS)

Winter, T.G.; Alston, S.G.

1990-01-01

Basic atomic-collision processes at intermediate and high energies are being studied theoretically at Penn State by Alston and Winter. In the high velocity regime, single-electron capture is treated using a high order multiple-scattering approach; extensive comparison with experiment and analysis of mechanisms have been made. Fitting the calculated amplitude with a simple analytic form, the asymptotic velocity dependence of the cross section is obtained. The effect on the capture amplitude of altering the inner part of the internuclear potential has also been explored. In the intermediate velocity regime, earlier work on collisions between protons and hydrogenic-ion targets using a coupled-state approach is being extended to the two-electron helium target. 29 refs

Resonance enhancement of neutrinoless double electron capture

International Nuclear Information System (INIS)

Krivoruchenko, M.I.; Simkovic, Fedor; Frekers, Dieter; Faessler, Amand

2011-01-01

The process of neutrinoless double electron (0νECEC) capture is revisited for those cases where the two participating atoms are nearly degenerate in mass. The theoretical framework is the formalism of an oscillation of two atoms with different total lepton number (and parity), one of which can be in an excited state so that mass degeneracy is realized. In such a case and assuming light Majorana neutrinos, the two atoms will be in a mixed configuration with respect to the weak interaction. A resonant enhancement of transitions between such pairs of atoms will occur, which could be detected by the subsequent electromagnetic de-excitation of the excited state of the daughter atom and nucleus. Available data of atomic masses, as well as nuclear and atomic excitations are used to select the most likely candidates for the resonant transitions. Assuming an effective mass for the Majorana neutrino of 1 eV, some half-lives are predicted to be as low as 10 22 years in the unitary limit. It is argued that, in order to obtain more accurate predictions for the 0νECEC half-lives, precision mass measurements of the atoms involved are necessary, which can readily be accomplished by today's high precision Penning traps. Further advancements also require a better understanding of high-lying excited states of the final nuclei (i.e. excitation energy, angular momentum and parity) and the calculation of the nuclear matrix elements.

Multiple scattering approach to the vibrational excitation of molecules by slow electrons

International Nuclear Information System (INIS)

Drukarev, G.

1976-01-01

Another approach to the problem of vibrational excitation of homonuclear two-atomic molecules by slow electrons possibly accompanied by rotational transitions is presented based on the picture of multiple scattering of an electron inside the molecule. The scattering of two fixed centers in the zero range potential model is considered. The results indicate that the multiple scattering determines the order of magnitude of the vibrational excitation cross sections in the energy region under consideration even if the zero range potential model is used. Also the connection between the multiple scattering approach and quasi-stationary molecular ion picture is established. 9 refs

Determination of DDTs and PCBs by capillary gas chromatography and electron capture detection

International Nuclear Information System (INIS)

1988-01-01

This reference method deals with the determination of DDTs and PCBs in marine environmental samples using high resolution gas chromatography. Several other halogenated pesticides and other electron capturing organic compounds may be present in samples and many of these may also be determined by this method. Not all electron capturing residues will be resistant to all of the clean up procedures described here for the analysis of DTTs and PCBs. Therefore, additional information on the stability of some common pesticides using this methodology is also provided. The high separation power of open tubular (''capillary'') columns allows the identification and quantification of many compounds in the complex mixtures occurring in environmental samples. This manual provides information on the theoretical and practical aspects of the use of these high resolution columns for the analysis of DDTs and PCBs in environmental samples. The qualitative and quantitative method can be applied to any sample type (aerosol/vapour, water, particulates, biota, etc.) provided that suitable cleaned-up extracts dissolved in n-hexane are available for injection into the GC system. For example, methods for obtaining these cleaned-up sample extracts from marine organisms are described in detail in UNEP Reference Method no. 14 and for sediments in No. 17. The change in the field of application by analysing by capillary rather than packed columns may be less dramatic for DDTs. However, with the increased separation, the possibilities of inaccurate analysis resulting from overlap with interfering compounds is reduced. 7 refs, 1 fig., 3 tabs

Electron capture in collisions of ? with H and ? with C

Science.gov (United States)

Stancil, P. C.; Gu, J.-P.; Havener, C. C.; Krstic, P. S.; Schultz, D. R.; Kimura, M.; Zygelman, B.; Hirsch, G.; Buenker, R. J.; Bannister, M. E.

1998-08-01

A comprehensive theoretical and experimental study of electron capture in collisions of 0953-4075/31/16/017/img15 with H and 0953-4075/31/16/017/img16 with C extending over the energy range 0953-4075/31/16/017/img17 to 0953-4075/31/16/017/img18 is presented. A variety of theoretical approaches were used including those based on quantal molecular-orbital close-coupling (MOCC), multielectron hidden crossings (MEHC), quantal decay and classical trajectory Monte Carlo techniques. Radiative charge transfer cross sections were computed using the optical potential/distorted wave (OPDW) and fully quantal (FQ) approaches. The MOCC, OPDW and FQ calculations incorporated ab initio potentials, nonadiabatic coupling matrix elements and transition moments computed at the configuration-interaction level. Ab initio potential surfaces in the plane of complex internuclear distance were obtained for the MEHC calculations. Merged-beam measurements were performed between 0953-4075/31/16/017/img19 and 0953-4075/31/16/017/img20 for the 0953-4075/31/16/017/img21 collision system. Diagnostics of the 0953-4075/31/16/017/img15 beam with a crossed electron beam could find no presence of a 0953-4075/31/16/017/img15 metastable component. The current results, in conjunction with previous measurements, are used to deduce a set of recommended cross sections.

The boundary-corrected second Born (B2B) approximation: proton-hydrogen electron capture

International Nuclear Information System (INIS)

Dewangan, D.P.; Bransden, B.H.

1988-01-01

The probability amplitude for proton-hydrogen ground-state electron capture at 125 keV in the boundary-corrected second Born approximation has been evaluated numerically by retaining all significant bound and continuum hydrogenic intermediate states for which the orbital angular momentum l ≤ 3. The differential cross section is found to be in good agreement with the experimental data for scattering angles less than about 1 mrad in the centre of mass system. The value of the boundary-corrected second Born total cross section is similar to that obtained in the boundary-corrected first Born approximation. (author)

Investigation of the Mechanism of Electron Capture and Electron Transfer Dissociation of Peptides with a Covalently Attached Free Radical Hydrogen Atom Scavenger.

Science.gov (United States)

Sohn, Chang Ho; Yin, Sheng; Peng, Ivory; Loo, Joseph A; Beauchamp, J L

2015-11-15

The mechanisms of electron capture and electron transfer dissociation (ECD and ETD) are investigated by covalently attaching a free-radical hydrogen atom scavenger to a peptide. The 2,2,6,6-tetramethylpiperidin-l-oxyl (TEMPO) radical was chosen as the scavenger due to its high hydrogen atom affinity (ca. 280 kJ/mol) and low electron affinity (ca. 0.45 ev), and was derivatized to the model peptide, FQX TEMPO EEQQQTEDELQDK. The X TEMPO residue represents a cysteinyl residue derivatized with an acetamido-TEMPO group. The acetamide group without TEMPO was also examined as a control. The gas phase proton affinity (882 kJ/mol) of TEMPO is similar to backbone amide carbonyls (889 kJ/mol), minimizing perturbation to internal solvation and sites of protonation of the derivatized peptides. Collision induced dissociation (CID) of the TEMPO tagged peptide dication generated stable odd-electron b and y type ions without indication of any TEMPO radical induced fragmentation initiated by hydrogen abstraction. The type and abundance of fragment ions observed in the CID spectra of the TEMPO and acetamide tagged peptides are very similar. However, ECD of the TEMPO labeled peptide dication yielded no backbone cleavage. We propose that a labile hydrogen atom in the charge reduced radical ions is scavenged by the TEMPO radical moiety, resulting in inhibition of N-C α backbone cleavage processes. Supplemental activation after electron attachment (ETcaD) and CID of the charge-reduced precursor ion generated by electron transfer of the TEMPO tagged peptide dication produced a series of b + H (b H ) and y + H (y H ) ions along with some c ions having suppressed intensities, consistent with stable O-H bond formation at the TEMPO group. In summary, the results indicate that ECD and ETD backbone cleavage processes are inhibited by scavenging of a labile hydrogen atom by the localized TEMPO radical moiety. This observation supports the conjecture that ECD and ETD processes involve long

Electron capture rates in stars studied with heavy ion charge exchange reactions

Science.gov (United States)

Bertulani, C. A.

2018-01-01

Indirect methods using nucleus-nucleus reactions at high energies (here, high energies mean ~ 50 MeV/nucleon and higher) are now routinely used to extract information of interest for nuclear astrophysics. This is of extreme relevance as many of the nuclei involved in stellar evolution are short-lived. Therefore, indirect methods became the focus of recent studies carried out in major nuclear physics facilities. Among such methods, heavy ion charge exchange is thought to be a useful tool to infer Gamow-Teller matrix elements needed to describe electron capture rates in stars and also double beta-decay experiments. In this short review, I provide a theoretical guidance based on a simple reaction model for charge exchange reactions.

Electron capture by multicharged ions from hydrogen atoms at eV energies

International Nuclear Information System (INIS)

Havener, C.C.; Nesnidal, M.P.; Porter, M.R.; Phaneuf, R.A.

1990-01-01

To quantitatively study electron capture during collisions of multiply charged ions with neutral atoms at near-thermal energies, keV-energy multicharged ion beams are merged with ground-state beams of H or D atoms of chosen velocity such that collisions in the relative energy range 1--1000 eV/amu result. Recent data for O 3+ , O 4+ + H(D) are presented and compared with theoretical predictions. Recently completed modifications to the apparatus are described that will provide a significant improvement in signal-to-background and angular collection. These improvements will allow measurements to be extended to lower energies, where effects due to the ion-induced dipole attraction may be evident

Deployment of vendor innovation capability in contract electronic manufacturing

DEFF Research Database (Denmark)

Perunovic, Zoran; Mefford, Robert N.

2012-01-01

This paper explores deployment of innovation capability in outsourcing from the vendor perspective. Vendor’s innovation-related competences are used to capture vendor innovativeness. A multiple-case study was applied with two Contract Electronic Manufacturers. Based on the data analysis we propose...

Gadolinium neutron capture therapy

International Nuclear Information System (INIS)

Akine, Yasuyuki; Tokita, Nobuhiko; Tokuuye, Koichi; Satoh, Michinao; Churei, Hisahiko

1993-01-01

Gadolinium neutron capture therapy makes use of photons and electrons produced by nuclear reactions between gadolinium and lower-energy neutrons which occur within the tumor. The results of our studies have shown that its radiation effect is mostly of low LET and that the electrons are the significant component in the over-all dose. The dose from gadolinium neutron capture reactions does not seem to increase in proportion to the gadolinium concentration, and the Gd-157 concentration of about 100 μg/ml appears most optimal for therapy. Close contact between gadolinium and the cell is not necessarily required for cell inactivation, however, the effect of electrons released from intracellular gadolinium may be significant. Experimental studies on tumor-bearing mice and rabbits have shown that this is a very promising modality though further improvements in gadolinium delivery to tumors are needed. (author)

Prediction of gas chromatography/electron capture detector retention times of chlorinated pesticides, herbicides, and organohalides by multivariate chemometrics methods

International Nuclear Information System (INIS)

Ghasemi, Jahanbakhsh; Asadpour, Saeid; Abdolmaleki, Azizeh

2007-01-01

A quantitative structure-retention relationship (QSRR) study, has been carried out on the gas chromatograph/electron capture detector (GC/ECD) system retention times (t R s) of 38 diverse chlorinated pesticides, herbicides, and organohalides by using molecular structural descriptors. Modeling of retention times of these compounds as a function of the theoretically derived descriptors was established by multiple linear regression (MLR) and partial least squares (PLS) regression. The stepwise regression using SPSS was used for the selection of the variables that resulted in the best-fitted models. Appropriate models with low standard errors and high correlation coefficients were obtained. Three types of molecular descriptors including electronic, steric and thermodynamic were used to develop a quantitative relationship between the retention times and structural properties. MLR and PLS analysis has been carried out to derive the best QSRR models. After variables selection, MLR and PLS methods used with leave-one-out cross validation for building the regression models. The predictive quality of the QSRR models were tested for an external prediction set of 12 compounds randomly chosen from 38 compounds. The PLS regression method was used to model the structure-retention relationships, more accurately. However, the results surprisingly showed more or less the same quality for MLR and PLS modeling according to squared regression coefficients R 2 which were 0.951 and 0.948 for MLR and PLS, respectively

Doubly differential single and multiple ionization of krypton by electron impact

International Nuclear Information System (INIS)

Lucio, O. G. de; Gavin, J.; DuBois, R. D.

2007-01-01

Differential measurements for single and multiple ionization of Kr by 240 and 500 eV electron impact are presented. Using a pulsed extraction field, Kr + , Kr 2+ , and Kr 3+ ions were measured in coincidence with scattered electrons for energy losses up to 120 eV and scattering angles between 16 degree sign and 90 degree sign . Scaling properties of the doubly differential cross sections (DDCS) are investigated as a function of energy loss, scattering angle, and momentum transfer. It is shown that scaling the DDCS as outlined by Kim and Inokuti and plotting them versus a parameter consisting of the momentum transfer divided by the square root of the impact energy times 1-cos(θ), where θ is the scattering angle, yielded similar curves, but with different magnitudes, for single and multiple ionization. Normalizing these curves together produced two universal curves, one appropriate for single and multiple electron emission at larger scattering angles (θ≥30 degree sign ) and one appropriate for small scattering angles (θ<30 degree sign )

Electron-capture delayed fission properties of neutron-deficient einsteinium nuclei

International Nuclear Information System (INIS)

Shaughnessy, Dawn A.

2000-01-01

Electron-capture delayed fission (ECDF) properties of neutron-deficient einsteinium isotopes were investigated using a combination of chemical separations and on-line radiation detection methods. 242 Es was produced via the 233 U( 14 N,5n) 242 Es reaction at a beam energy of 87 MeV (on target) in the lab system, and was found to decay with a half-life of 11 ± 3 seconds. The ECDF of 242 Es showed a highly asymmetric mass distribution with an average pre-neutron emission total kinetic energy (TKE) of 183 ± 18 MeV. The probability of delayed fission (P DF ) was measured to be 0.006 ± 0.002. In conjunction with this experiment, the excitation functions of the 233 U( 14 N,xn) 247-x Es and 233 U( 15 N,xn) 248-x Es reactions were measured for 243 Es, 244 Es and 245 Es at projectile energies between 80 MeV and 100 MeV

Single-electron-capture processes in collisions of He2+, Liq+ (q=1,2,3), C6+, and O8+ ions with helium

International Nuclear Information System (INIS)

Samanta, R.; Purkait, M.; Mandal, C. R.

2011-01-01

Cross sections for single-electron capture in collisions of He 2+ , Li q+ (q = 1,2,3), C 6+ , and O 8+ ions with helium atoms at incident energy ranging from 50 to 5000 keV/amu have been calculated in the framework of four-body boundary-corrected continuum intermediate state (BCCIS-4B) approximation in both prior and post forms. In this formalism, distortion in the final channel related to the Coulomb continuum states of the projectile ion and the active electron in the field of residual target ion are included. In all cases, total single-electron-capture cross sections have been calculated by summing over all contributions up to n = 3 shells and subshells, respectively. It has been observed that the contribution of the capture cross section into the excited states is significant for asymmetric collision (Z P >Z T ) and is insignificant for symmetric collision. Numerical results for the total cross sections show good agreement with the available experimental findings, particularly in the post form. Post-prior discrepancy has been found to be within 30% except for Li + + He interactions below 150 keV/amu.

Calibration of radionuclides with decay trough beta emission or electron capture by liquid scintillation technique

International Nuclear Information System (INIS)

Loureiro, Jamir dos Santos

2000-02-01

In this work is reported a methodology a methodology for pure beta and electron capture radionuclides standardization, suing liquid scintillation technique. In this sense the CIEMAT/NIST method, recently utilized by international laboratories, was implemented and the lack in the Laboratorio Nacional das Radiacoes Ionizantes - LNMRI, of the Comissao Nacional de Energia Nuclear - CNEN, for adequate methodology to standardize this kind if radionuclides was filled, fact that was not present with alpha and gamma radionuclides. The implementation procedure evaluation was provided by concentration activity determination of the following radionuclides: 14 C and 90 Sr, pure beta emitters; 55 Fe, electron capture decay; 204 Tl, electron capture and beta decay and 60 Co, beta-gamma emitter. In this way, a careful analysis of the implementation procedure with these radionuclides types, ranging on a broad energy spectral, was possible. To check the calibration results, intercomparisons among our measurements of these radionuclides and the reference values of the CIEMAT/Spain laboratory were provided. To check the calibration results, intercomparisons among our measurements of these radionuclides and the reference values of the CIEMAT/Spain laboratory were provided. Besides this intercomparisons, one was provided with a 204 Tl solution, utilized in the international comparison recently promoted by BIPM, and another one with a 60 C solution calibrated in LNMRI/CNEN previously by a relative calibration system, with a well type pressurized ionization chamber, and an absolute beta-gamma coincidence system, with a pill-box type proportional counter 4 π geometry, coupled with a scintillator system with a sodium iodide cristal of 4x4 inches. The comparisons among LNMRI/CNEN results and the reference values, showed a small deviation of 1,32% for 14 C, 0,40% for 60 Co, 1,12% for 55 Fe, 0,10% for 90 Sr and 0,73% for 204 Tl. For the BIPM solution the deviation was 0,46% and for 60 Co

Intermolecular effects on the radiogenic formation of electron-capture phosphorus-centered radicals. A single-crystal ESR study of diastereoisomeric precursors

Energy Technology Data Exchange (ETDEWEB)

Aagaard, O.M.; Janssen, R.A.J.; de Waal, B.F.M.; Buck, H.M. (Eindhoven Univ. of Technology (Netherlands))

1990-01-31

ESR experiments on X-irradiated single crystals of the 2R,4S,5R and 2S,4S,5R diastereoisomers of 2-chloro-3,4-dimethyl-5-phenyl-1,3,2-oxazaphospholidine 2-sulfide reveal that the yield of radiogenic electron-capture reactions in the solid state strongly depends on intermolecular interactions in the crystal. In the present case a high yield of P-Cl three-electron-bond phosphoranyl radical anions is found in crystals of the 2R,4S,5R isomer, whereas no radical formation can be detected for the 2S,4S,5R isomer. An analysis of nonbonded interactions with neighboring molecules reveals that the geometry relaxation necessary for the radical stabilization is easily accommodated in crystals of the 2R,4S,SR isomer but not in the 2S,4S,5R isomer, explaining the observed difference in electron-capture efficiency. Experiments on radical formation in a MeTHF host matrix give further insight into the importance of the environment on radiogenic radical formation. The possible concurrent effect of the matrix on the electronic configuration and spin density distribution of the resulting phosphoranyl radical is discussed.

Intermolecular effects on the radiogenic formation of electron-capture phosphorus-centered radicals. A single-crystal ESR study of diastereoisomeric precursors

International Nuclear Information System (INIS)

Aagaard, O.M.; Janssen, R.A.J.; de Waal, B.F.M.; Buck, H.M.

1990-01-01

ESR experiments on X-irradiated single crystals of the 2R,4S,5R and 2S,4S,5R diastereoisomers of 2-chloro-3,4-dimethyl-5-phenyl-1,3,2-oxazaphospholidine 2-sulfide reveal that the yield of radiogenic electron-capture reactions in the solid state strongly depends on intermolecular interactions in the crystal. In the present case a high yield of P-Cl three-electron-bond phosphoranyl radical anions is found in crystals of the 2R,4S,5R isomer, whereas no radical formation can be detected for the 2S,4S,5R isomer. An analysis of nonbonded interactions with neighboring molecules reveals that the geometry relaxation necessary for the radical stabilization is easily accommodated in crystals of the 2R,4S,SR isomer but not in the 2S,4S,5R isomer, explaining the observed difference in electron-capture efficiency. Experiments on radical formation in a MeTHF host matrix give further insight into the importance of the environment on radiogenic radical formation. The possible concurrent effect of the matrix on the electronic configuration and spin density distribution of the resulting phosphoranyl radical is discussed

Atomic and nuclear parameters of single electron capture decaying nuclides; Constantes atomicas y nucleares de nucleidos que se desintegran por captura electronica pura

Energy Technology Data Exchange (ETDEWEB)

Grau, A

1981-07-01

Atomic and nuclear parameters of the following nuclides which decay by electron capture have been calculated: 37{sup A}r, 41{sup C}a, 49{sup V}, 53{sup M}n, 55{sup F}e,59{sup N}i, 68Ge,82{sup S}r, 97{sup T}c, 118{sup T}e, 131{sup C}s, 137{sup L}a, 140{sup N}d, 157{sup T}b, 165{sup E}r, 193{sup p}t, 194{sup H}g, and 205{sup P}h The evaluation rules are included in the first part of the paper. The values and the associated uncertainties of the following parameters have been tabulated: decay energy, electron capture probabilities, fluorescence yield, electron emission and X-ray emission. (Author) 27 refs.

Practical enhancement factor model based on GM for multiple parallel reactions: Piperazine (PZ) CO2 capture

DEFF Research Database (Denmark)

Gaspar, Jozsef; Fosbøl, Philip Loldrup

2017-01-01

Reactive absorption is a key process for gas separation and purification and it is the main technology for CO2 capture. Thus, reliable and simple mathematical models for mass transfer rate calculation are essential. Models which apply to parallel interacting and non-interacting reactions, for all......, desorption and pinch conditions.In this work, we apply the GM model to multiple parallel reactions. We deduce the model for piperazine (PZ) CO2 capture and we validate it against wetted-wall column measurements using 2, 5 and 8 molal PZ for temperatures between 40 °C and 100 °C and CO2 loadings between 0.......23 and 0.41 mol CO2/2 mol PZ. We show that overall second order kinetics describes well the reaction between CO2 and PZ accounting for the carbamate and bicarbamate reactions. Here we prove the GM model for piperazine and MEA but we expect that this practical approach is applicable for various amines...

Metadata capture in an electronic notebook: How to make it as simple as possible?

Directory of Open Access Journals (Sweden)

Menzel, Julia

2015-09-01

Full Text Available In the last few years electronic laboratory notebooks (ELNs have become popular. ELNs offer the great possibility to capture metadata automatically. Due to the high documentation effort metadata documentation is neglected in science. To close the gap between good data documentation and high documentation effort for the scientists a first user-friendly solution to capture metadata in an easy way was developed.At first, different protocols for the Western Blot were collected within the Collaborative Research Center 1002 and analyzed. Together with existing metadata standards identified in a literature search a first version of the metadata scheme was developed. Secondly, the metadata scheme was customized for future users including the implementation of default values for automated metadata documentation.Twelve protocols for the Western Blot were used to construct one standard protocol with ten different experimental steps. Three already existing metadata standards were used as models to construct the first version of the metadata scheme consisting of 133 data fields in ten experimental steps. Through a revision with future users the final metadata scheme was shortened to 90 items in three experimental steps. Using individualized default values 51.1% of the metadata can be captured with present values in the ELN.This lowers the data documentation effort. At the same time, researcher could benefit by providing standardized metadata for data sharing and re-use.

Electron-electron interaction and transfer ionization in fast ion-atom collisions

International Nuclear Information System (INIS)

Voitkiv, A B

2008-01-01

Recently it was pointed out that electron capture occurring in fast ion-atom collisions can proceed via a mechanism which earlier was not considered. In the present paper we study this mechanism in more detail. Similarly as in radiative capture, where the electron transfer occurs due to the interaction with the radiation field and proceeds via emission of a photon, within this mechanism the electron capture is caused by the interaction with another atomic electron leading mainly to the emission of the latter. In contrast to the electron-electron Thomas capture, this electron-electron (E-E) mechanism is basically a first-order one having similarities to the kinematic and radiative capture channels. It also possesses important differences with the latter two. Leading to transfer ionization, this first-order capture mechanism results in the electron emission mainly in the direction opposite to the motion of the projectile ion. The same, although less pronounced, feature is also characteristic for the momenta of the target recoil ions produced via this mechanism. It is also shown that the action of the E-E mechanism is clearly seen in recent experimental data on the transfer ionization in fast proton-helium collisions.

Analysis of neonicotinoids by gas chromatography coupled to nuclide {sup 63}Ni - Electron Capture Detector - GC/ECD

Energy Technology Data Exchange (ETDEWEB)

Amaral, Priscila O.; Leao, Claudio; Redigolo, Marcelo M.; Crepaldi, Caike; Bustillos, Oscar V., E-mail: priscilaoamaral@gmail.com, E-mail: claudio.leao@usp.br, E-mail: marceloredigolo@gmail.com, E-mail: caike1995@gmail.com, E-mail: ovega@ipen.bremails [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

Recently, several reports have been published discussing reduction in bee population which polymerizes cultures around the world this phenomenon is known as Colony Collapse Disorder (CCD). The phenomenon describes the lack of worker honeybees in the colony despite having pups and food. The causes of this problem are unknown but there are studies that claim that reduction of population of bees is linked to poisoning through insecticides specifically neonicotinoids. Among this type of pesticide are imidacloprid (C{sub 9}H{sub 10}ClN{sub 5}O{sub 2}), clothianidin (C{sub 6}H{sub 8}ClN{sub 5}O{sub 2}S) and thiamethoxam (C{sub 8}H{sub 10}ClN{sub 5}O{sub 3}S). This paper presents the analysis of neonicotinoids - clothianidin, imidacloprid and thiamethoxam - by the technique of gas chromatography coupled to nuclide {sup 63}Ni electron capture detector (GC/ECD). The electron capture detector (ECD) is a gas chromatography detector that has been used for the detection of organic halogens, nitriles, nitrates and organometallic compounds. The ECD detector ionizes the analytes by the beta particles from the nuclide sources {sup 63}Ni within carrier gas N{sub 2}. The electrons produced in this process are collected and create a current that are amplified and generates a chromatographic peak. Methodology and details of the analysis are present in this work. (author)

Continuum and bound electronic wavefunctions for anisotropic multiple-scattering potentials

International Nuclear Information System (INIS)

Siegel, J.; Dill, D.; Dehmer, J.L.

1975-01-01

Standard multiple-scattering treatments of bound and continuum one-electron states are restricted to a monopole potential in each of the various spherical regions. We have extended the treatment within these regions to a general potential. The corresponding multiple-scattering equations should facilitate accurate treatment of effects of the build-up of charge due to bonding, of the dipole character of polar molecules, and of external fields

Low energy electron capture in collisions of C3+ with He

International Nuclear Information System (INIS)

Wu, Y.; Qi, Y.Y.; Yan, J.; Wang, J.G.; Li, Y.; Buenker, R.J.; Kato, D.

2009-06-01

Charge transfer processes due to collisions of ground state C 3+ (1s 2 2s 2 S) ions with He atom are investigated using the quantum-mechanical molecular-orbital close-coupling (QMOCC) method for energies between 10 -4 eV/u and 10 3 eV/u. The ab initio adiabatic potential and radial coupling utilized in the QMOCC calculations are obtained from the multi-reference single- and double-excitation configuration interaction (MRD-CI) approach. Total and state-selective single electron capture (SEC) cross sections and rate coefficients are obtained and compared with the available experimental and theoretical data. Good agreement between the measured SEC cross sections and the present calculation is found, but the previous calculation of total rate coefficient using the Landau-Zener model is one or two orders of magnitude smaller than the present result. (author)

Statistics of electron multiplication in a multiplier phototube; Iterative method; Estadistica de la multiplicacion de electrones en un fotomultiplicador: Metodos iterativos

Energy Technology Data Exchange (ETDEWEB)

Ortiz, J F; Grau, A

1985-07-01

In the present paper an iterative method is applied to study the variation of dynode response in the multiplier phototube. Three different situation are considered that correspond to the following ways of electronic incidence on the first dynode: incidence of exactly one electron, incidence of exactly r electrons and incidence of an average r electrons. The responses are given for a number of steps between 1 and 5, and for values of the multiplication factor of 2.1, 2.5, 3 and 5. We study also the variance, the skewness and the excess of jurtosis for different multiplication factors. (Author) 11 refs.

Capturing Chemistry in Action with Electrons: Realization of Atomically Resolved Reaction Dynamics.

Science.gov (United States)

Ischenko, Anatoly A; Weber, Peter M; Miller, R J Dwayne

2017-08-23

One of the grand challenges in chemistry has been to directly observe atomic motions during chemical processes. The depiction of the nuclear configurations in space-time to understand barrier crossing events has served as a unifying intellectual theme connecting the different disciplines of chemistry. This challenge has been cast as an imaging problem in which the technical issues reduce to achieving not only sufficient simultaneous space-time resolution but also brightness for sufficient image contrast to capture the atomic motions. This objective has been met with electrons as the imaging source. The review chronicles the first use of electron structural probes to study reactive intermediates, to the development of high bunch charge electron pulses with sufficient combined spatial-temporal resolution and intensity to literally light up atomic motions, as well as the means to characterize the electron pulses in terms of temporal brightness and image reconstruction. The use of femtosecond Rydberg spectroscopy as a novel means to use internal electron scattering within the molecular reference frame to obtain similar information on reaction dynamics is also discussed. The focus is on atomically resolved chemical reaction dynamics with pertinent references to work in other areas and forms of spectroscopy that provide additional information. Effectively, we can now directly observe the far-from-equilibrium atomic motions involved in barrier crossing and categorize chemistry in terms of a power spectrum of a few dominant reaction modes. It is this reduction in dimensionality that makes chemical reaction mechanisms transferrable to seemingly arbitrarily complex (large N) systems, up to molecules as large as biological macromolecules (N > 1000 atoms). We now have a new way to reformulate reaction mechanisms using an experimentally determined dynamic mode basis that in combination with recent theoretical advances has the potential to lead to a new conceptual basis for

Electronic capture of patient-reported and clinician-reported outcome measures in an elective orthopaedic setting: a retrospective cohort analysis.

Science.gov (United States)

Malhotra, Karan; Buraimoh, Olatunbosun; Thornton, James; Cullen, Nicholas; Singh, Dishan; Goldberg, Andrew J

2016-06-20

To determine whether an entirely electronic system can be used to capture both patient-reported outcomes (electronic Patient-Reported Outcome Measures, ePROMs) as well as clinician-validated diagnostic and complexity data in an elective surgical orthopaedic outpatient setting. To examine patients' experience of this system and factors impacting their experience. Retrospective analysis of prospectively collected data. Single centre series. Outpatient clinics at an elective foot and ankle unit in the UK. All new adult patients attending elective orthopaedic outpatient clinics over a 32-month period. All patients were invited to complete ePROMs prior to attending their outpatient appointment. At their appointment, those patients who had not completed ePROMs were offered the opportunity to complete it on a tablet device with technical support. Matched diagnostic and complexity data were captured by the treating consultant during the appointment. Capture rates of patient-reported and clinician-reported data. All information and technology (IT) failures, language and disability barriers were captured. Patients were asked to rate their experience of using ePROMs. The scoring systems used included EQ-5D-5L, the Manchester-Oxford Foot Questionnaire (MOxFQ) and the Visual Analogue Scale (VAS) pain score. Out of 2534 new patients, 2176 (85.9%) completed ePROMs, of whom 1090 (50.09%) completed ePROMs at home/work prior to their appointment. 31.5% used a mobile (smartphone/tablet) device. Clinician-reported data were captured on 2491 patients (98.3%). The mean patient experience score of using Patient-Reported Outcome Measures (PROMs) was 8.55±1.85 out of 10 and 666 patients (30.61%) left comments. Of patients leaving comments, 214 (32.13%) felt ePROMs did not adequately capture their symptoms and these patients had significantly lower patient experience scores (ptechnology into a service improvement programme. Excellent capture rates of ePROMs and clinician

The coulometric electron capture detector and its application to the selected freons in water and air. Part of a coordinated programme on the analysis of organic compounds by electron capture gas chromatography

International Nuclear Information System (INIS)

Lasa, J.

1981-01-01

In developing the use of Freon-11 and Freon-12 as environmental tracers in aeronomy, oceanography and hydrology electron capture gas chromatography was used to measure the concentration changes. A detector in the coulometric mode was designed and operated as a solute switch. The detection limit was in the order of 0.2x10 -12 g for a modified head space method in handling aqueous samples. Theoretical analysis of the detector design and the effects of factors including pulsing period, flowrates of carrier gas and the radioactivity of the detector source were discussed and confirmed experimentally

Hafnium Resonance Parameter Analysis Using Neutron Capture and Transmission Experiments

International Nuclear Information System (INIS)

MJ Trbovich; DP Barry; RE Slovacck; Y Danon; RC Block; JA Burke; NJ Drindak; G Leinweber; RV Ballad

2004-01-01

The focus of this work is to determine resonance parameters for stable hafnium isotopes in the 0.005-200 eV region, with special emphasis on the overlapping 176 Hf and 178 Hf resonances near 8 eV. The large neutron cross section of hafnium, combined with its corrosion resistance and excellent mechanical properties, make it a useful material for controlling nuclear reactions. Experiments measuring neutron capture and transmission were performed at the Rensselaer Polytechnic Institute (RPI) electron linear accelerator (LINAC) using the time of flight method. 6 Li glass scintillation detectors were used for transmission experiments at flight path lengths of 15 and 25 m. Capture experiments were done using a sixteen section NaI(Tl) multiplicity detector at a flight path length of 25 m. These experiments utilized various thicknesses of metallic and isotopically-enriched liquid samples. The liquid samples were designed to provide information on the 176 Hf and 178 Hf contributions to the 8 eV doublet without saturation. Data analysis was done using the R-matrix Bayesian code SAMMY version M6 beta. SAMMY is able to account for experimental resolution effects for each of the experimental setups at the RPI LINAC, and also can correct for multiple scattering effects in neutron capture yield data. The combined capture and transmission data analysis yielded resonance parameters for all hafnium isotopes from 0.005-200 eV. Resonance integrals were calculated along with errors for each hafnium isotope using the NJOY [1] and INTER [2] codes. The isotopic resonance integrals calculated were significantly different than previously published values; however the calculated elemental hafnium resonance integral changed very little

Electron capture in very low energy collisions of multicharged ions with H and D in merged beams

International Nuclear Information System (INIS)

Havener, C.C.; Meyer, F.W.; Phaneuf, R.A.

1991-01-01

An ion-atom merged-beams technique is being used to measure total absolute electron-capture cross sections for multicharged ions in collisions with H (or D) in the energy range between 0.1 and 1000 eV/amu. Comparison between experiment and theory over such a large energy range constitutes a critical test for both experiment and theory. Total capture cross-section measurements for O 3+ H(D) and O 5+ + H(D) are presented and compared to state selective and differential cross section calculations. Landau-Zener calculations show that for O 5+ the sharp increase in the measured cross section below 1 eV/amu is partly due to trajectory effects arising from the ion-induced dipole interaction between the reactants. 20 refs., 8 figs

Double capture in the O8+ + He collision investigated by electron spectroscopy (80 keV, 10 deg)

International Nuclear Information System (INIS)

Moretto-Capelle, P.; Benoit-Cattin, P.; Bordenave-Montesquieu, A.; Boudjema, M.; Gleizes, A.; Dousson, S.; Hitz, D.

1989-01-01

Double capture into (3,n) autoionising states of O 6+ is observed in the O 8+ + He collision system by electron spectroscopy at 80 keV, 10 0 . A comparison of the experimental results with theoretical positions and lifetimes allows the (3,3) states as well as three groups of (3,4) states to be identified. The present experimental findings are compared with earlier data for the N 7+ + He and Ne 8+ (1s 2 ) + He systems. The influence of the core of the multicharged ion is studied by examining the O 8+ and Ne 8+ (1s 2 ) results. The total double capture cross section is found to be large and it is compared with available experimental and theoretical data. (author)

A Benefit-Risk Analysis Approach to Capture Regulatory Decision-Making: Multiple Myeloma.

Science.gov (United States)

Raju, G K; Gurumurthi, Karthik; Domike, Reuben; Kazandjian, Dickran; Landgren, Ola; Blumenthal, Gideon M; Farrell, Ann; Pazdur, Richard; Woodcock, Janet

2018-01-01

Drug regulators around the world make decisions about drug approvability based on qualitative benefit-risk analysis. In this work, a quantitative benefit-risk analysis approach captures regulatory decision-making about new drugs to treat multiple myeloma (MM). MM assessments have been based on endpoints such as time to progression (TTP), progression-free survival (PFS), and objective response rate (ORR) which are different than benefit-risk analysis based on overall survival (OS). Twenty-three FDA decisions on MM drugs submitted to FDA between 2003 and 2016 were identified and analyzed. The benefits and risks were quantified relative to comparators (typically the control arm of the clinical trial) to estimate whether the median benefit-risk was positive or negative. A sensitivity analysis was demonstrated using ixazomib to explore the magnitude of uncertainty. FDA approval decision outcomes were consistent and logical using this benefit-risk framework. © 2017 American Society for Clinical Pharmacology and Therapeutics.

A new apparatus for electron-ion multiple coincidence momentum imaging spectroscopy

International Nuclear Information System (INIS)

Morishita, Y.; Kato, M.; Pruemper, G.; Liu, X.-J.; Lischke, T.; Ueda, K.; Tamenori, Y.; Oura, M.; Yamaoka, H.; Suzuki, I.H.; Saito, N.

2006-01-01

We have developed a new experimental apparatus for the electron-ion multiple coincidence momentum imaging spectroscopy in order to obtain the angular distributions of vibration-resolved photoelectrons from molecules fixed in space. The apparatus consists of a four-stage molecular supersonic jet and a spectrometer analyzing three-dimensional momenta of fragment ions and electrons in coincidence

Interaction of multicharged ions with molecules (CO2, C60) by coincident electron spectroscopy

International Nuclear Information System (INIS)

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

2001-01-01

First results for the investigation of electron capture processes in collisions between multicharged ions and molecule targets using electron spectroscopy in coincidence with charged fragments, are presented. It is shown that a much more detailed investigation of the capture reaction can be achieved using molecular instead of heavy atomic targets provided that an analysis of the target dissociation is made. The collisional systems 18 O 8+ +Ar, CO 2 and C 60 have been studied at 80 keV. Non coincident electron spectra as well as first results of double or triple coincidence experiments are discussed. Kinetic energy distributions of the C n + fragments (n=1 to 8) produced in multiple capture processes from C 60 target are given. A detailed investigation of the double capture process with CO 2 molecule allows the measurement of kinetic energy release distributions (KERD) which characterize the dissociation of CO 2 2+ molecular ions; our results are found to be very similar to those measured in double photoionisation experiments. (orig.)

A compact multi-plate fission chamber for the simultaneous measurement of 233U capture and fission cross-sections

Directory of Open Access Journals (Sweden)

Bacak M.

2017-01-01

Full Text Available 233U plays the essential role of fissile nucleus in the Th-U fuel cycle. A particularity of 233U is its small neutron capture cross-section which is about one order of magnitude lower than the fission cross-section on average. Therefore, the accuracy in the measurement of the 233U capture cross-section essentially relies on efficient capture-fission discrimination thus a combined setup of fission and γ-detectors is needed. At CERN n_TOF the Total Absorption Calorimeter (TAC coupled with compact fission detectors is used. Previously used MicroMegas (MGAS detectors showed significant γ-background issues above 100 eV coming from the copper mesh. A new measurement campaign of the 233U capture cross-section and alpha ratio is planned at the CERN n_TOF facility. For this measurement, a novel cylindrical multi ionization cell chamber was developed in order to provide a compact solution for 14 active targets read out by 8 anodes. Due to the high specific activity of 233U fast timing properties are required and achieved with the use of customized electronics and the very fast ionizing gas CF4 together with a high electric field strength. This paper describes the new fission chamber and the results of the first tests with neutrons at GELINA proving that it is suitable for the 233U measurement.

A fast calculating two-stream-like multiple scattering algorithm that captures azimuthal and elevation variations

Science.gov (United States)

Fiorino, Steven T.; Elmore, Brannon; Schmidt, Jaclyn; Matchefts, Elizabeth; Burley, Jarred L.

2016-05-01

Properly accounting for multiple scattering effects can have important implications for remote sensing and possibly directed energy applications. For example, increasing path radiance can affect signal noise. This study describes the implementation of a fast-calculating two-stream-like multiple scattering algorithm that captures azimuthal and elevation variations into the Laser Environmental Effects Definition and Reference (LEEDR) atmospheric characterization and radiative transfer code. The multiple scattering algorithm fully solves for molecular, aerosol, cloud, and precipitation single-scatter layer effects with a Mie algorithm at every calculation point/layer rather than an interpolated value from a pre-calculated look-up-table. This top-down cumulative diffusivity method first considers the incident solar radiance contribution to a given layer accounting for solid angle and elevation, and it then measures the contribution of diffused energy from previous layers based on the transmission of the current level to produce a cumulative radiance that is reflected from a surface and measured at the aperture at the observer. Then a unique set of asymmetry and backscattering phase function parameter calculations are made which account for the radiance loss due to the molecular and aerosol constituent reflectivity within a level and allows for a more accurate characterization of diffuse layers that contribute to multiple scattered radiances in inhomogeneous atmospheres. The code logic is valid for spectral bands between 200 nm and radio wavelengths, and the accuracy is demonstrated by comparing the results from LEEDR to observed sky radiance data.

Cross sections of electron loss and capture for beams of O+ in water vapor from the energy range of 0,2 to 1,2 MeV

International Nuclear Information System (INIS)

Oliveira, Vitor Jesus de

2015-01-01

The study of the interactions between atoms and molecules is important for the knowledge of the cross sections of the processes that contribute to the deposition of energy by charged particle beams used in radiotherapy planning and transport particle simulation codes. Heavy ions, such as oxygen, induce many cellular and molecular damages in human cells.as a result of interaction between the projectile and atoms and molecules. The use of proton and carbon as the projectile interacting with water molecules is well characterized, however there are few studies with oxygen ions. In this work we are interested in the study of electron loss (projectile ionization) and electron capture with charge state 1+. The Pelletron accelerator of 1.7 MeV from the Federal University of Rio de Janeiro housed in the Atomic and Molecular collisions Laboratory (LACAM) has been used, which can accelerate atomic and molecular ions up to speeds of the order of hundredths of light speed, and consists of the source of negative ions, the Wien filter, the accelerator itself and the magnet load selector. The detection device used to evaluate the processes of interaction (capture and loss) between the beam of the O + and the water molecule is a Microchannel Plate (MCP) at the position sensitive anode. The collisions of O + beans are being studied in the range of 0.2 to 1.2 MeV with water vapor (Z = 10). Were obtained the respective absolute cross sections for electron loss and electron capture and compared with the cross sections of the molecule methane (CH4 → Z = 10), the isoelectronic water molecule. The experimental results show an agreement between the measurements with water and methane. Comparisons were made with results of theoretical models for electron loss using the 'Free Collision Model' and for capture the Bohr and Lindhard model. The theoretical results for electron loss show an agreement of experimental data with the model used. The model of Bohr and Lindhard describes

A review of electron-capture and electron-transfer dissociation tandem mass spectrometry in polymer chemistry

International Nuclear Information System (INIS)

Hart-Smith, Gene

2014-01-01

Graphical abstract: -- Highlights: •ECD and ETD can produce unique and diagnostically useful polymer ion fragmentation data. •The operating principles of ECD and ETD are discussed in relation to other dissociation techniques. •Key characteristics of ECD and ETD spectra, as observed from biological analytes, are discussed. •ECD and ETD analyses are compared to CID analyses for different classes of synthetic polymer. -- Abstract: Mass spectrometry (MS)-based studies of synthetic polymers often characterise detected polymer components using mass data alone. However when mass-based characterisations are ambiguous, tandem MS (MS/MS) offers a means by which additional analytical information may be collected. This review provides a synopsis of two particularly promising methods of dissociating polymer ions during MS/MS: electron-capture and electron-transfer dissociation (ECD and ETD, respectively). The article opens with a summary of the basic characteristics and operating principles of ECD and ETD, and relates these techniques to other methods of dissociating gas-phase ions, such as collision-induced dissociation (CID). Insights into ECD- and ETD-based MS/MS, gained from studies into proteins and peptides, are then discussed in relation to polymer chemistry. Finally, ECD- and ETD-based studies into various classes of polymer are summarised; for each polymer class, ECD- and ETD-derived data are compared to CID-derived data. These discussions identify ECD and ETD as powerful means by which unique and diagnostically useful polymer ion fragmentation data may be generated, and techniques worthy of increased utilisation by the polymer chemistry community

Alignment in double capture processes

International Nuclear Information System (INIS)

Moretto-Capelle, P.; Benhenni, M.; Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A.

1993-01-01

The electron spectra emitted when a double capture occurs in N 7+ +He and Ne 8+ +He systems at 10 qkeV collisional energy, allow us to determine the angular distributions of the 3 ell 3 ell ' lines through a special spectra fitting procedure which includes interferences between neighbouring states. It is found that the doubly excited states populated in double capture processes are generally aligned

Double electron capture in collisions of the helium-like ions N5+, O6+ and Ne8+ with helium atoms

International Nuclear Information System (INIS)

Boudjema, M.; Moretto-Capelle, P.; Bordenave-Montesquieu, A.

1989-01-01

A fitting procedure of 1s 2 3l3l' lines observed in A (z-2)+ (1s 2 )+He collisions (Z = 7, 8 and 10), at 10 q keV collision energy (q = Z -2) and 10 0 observation angle, allows us to compare new theoretical positions and lifetimes, and experimental electron spectra. It is found that the spin conservation rule holds and that only singlet states are populated in these capture processes. As in N 7+ and O 8+ + He systems, capture into the highest angular momentum 1 G state is favoured in O 6+ and Ne 8+ + He systems and accounts for 26% of the double capture at 10 0 . In N 5+ + He, the L distribution is broader and no L value is clearly predominant. (author)

Enhancing Protein Disulfide Bond Cleavage by UV Excitation and Electron Capture Dissociation for Top-Down Mass Spectrometry

OpenAIRE

Wongkongkathep, Piriya; Li, Huilin; Zhang, Xing; Loo, Rachel R. Ogorzalek; Julian, Ryan R.; Loo, Joseph A.

2015-01-01

The application of ion pre-activation with 266 nm ultraviolet (UV) laser irradiation combined with electron capture dissociation (ECD) is demonstrated to enhance top-down mass spectrometry sequence coverage of disulfide bond containing proteins. UV-based activation can homolytically cleave a disulfide bond to yield two separated thiol radicals. Activated ECD experiments of insulin and ribonuclease A containing three and four disulfide bonds, respectively, were performed. UV-activation in comb...

Many-electron model for multiple ionization in atomic collisions

International Nuclear Information System (INIS)

Archubi, C D; Montanari, C C; Miraglia, J E

2007-01-01

We have developed a many-electron model for multiple ionization of heavy atoms bombarded by bare ions. It is based on the transport equation for an ion in an inhomogeneous electronic density. Ionization probabilities are obtained by employing the shell-to-shell local plasma approximation with the Levine and Louie dielectric function to take into account the binding energy of each shell. Post-collisional contributions due to Auger-like processes are taken into account by employing recent photoemission data. Results for single-to-quadruple ionization of Ne, Ar, Kr and Xe by protons are presented showing a very good agreement with experimental data

Many-electron model for multiple ionization in atomic collisions

Energy Technology Data Exchange (ETDEWEB)

Archubi, C D [Instituto de AstronomIa y Fisica del Espacio, Casilla de Correo 67, Sucursal 28 (C1428EGA) Buenos Aires (Argentina); Montanari, C C [Instituto de AstronomIa y Fisica del Espacio, Casilla de Correo 67, Sucursal 28 (C1428EGA) Buenos Aires (Argentina); Miraglia, J E [Instituto de AstronomIa y Fisica del Espacio, Casilla de Correo 67, Sucursal 28 (C1428EGA) Buenos Aires (Argentina)

2007-03-14

We have developed a many-electron model for multiple ionization of heavy atoms bombarded by bare ions. It is based on the transport equation for an ion in an inhomogeneous electronic density. Ionization probabilities are obtained by employing the shell-to-shell local plasma approximation with the Levine and Louie dielectric function to take into account the binding energy of each shell. Post-collisional contributions due to Auger-like processes are taken into account by employing recent photoemission data. Results for single-to-quadruple ionization of Ne, Ar, Kr and Xe by protons are presented showing a very good agreement with experimental data.

CAMAC - supported electronic set-up for the determination of the capture cross section of the reaction 1H(n,d)γ

International Nuclear Information System (INIS)

Hutsch, J.; Moeller, K.; Moesner, J.; Neubert, W.; Pilz, W.; Schmidt, G.; Stiehler, T.; Kudin, L.G.; Spiridenkov, E.M.; Volkov, S.S.

1984-08-01

After a brief description of the physical problem the experimental apparatus and the electronic set-up for the investigation of the capture reaction 1 H(n,d)γ at E/sub n/ = 25 MeV are described. (author)

Formation of negative hydrogen ion: polarization electron capture and nonthermal shielding.

Science.gov (United States)

Ki, Dae-Han; Jung, Young-Dae

2012-09-07

The influence of the nonthermal shielding on the formation of the negative hydrogen ion (H(-)) by the polarization electron capture are investigated in partially ionized generalized Lorentzian plasmas. The Bohr-Lindhard method has been applied to obtain the negative hydrogen formation radius and cross section as functions of the collision energy, de Broglie wave length, Debye length, impact parameter, and spectral index of the plasma. The result shows that the nonthermal character of the plasma enhances the formation radius of the negative hydrogen, especially, for small Debye radii. It is found that the nonthermal effect increases the formation cross section of the negative hydrogen. It is also found that the maximum position of the formation cross section approaches to the collision center with an increase of the spectral index. In addition, it is found that the formation cross section significantly decreases with an increase of the Debye length, especially, for small spectral indices.

Formation of negative hydrogen ion: Polarization electron capture and nonthermal shielding

International Nuclear Information System (INIS)

Ki, Dae-Han; Jung, Young-Dae

2012-01-01

The influence of the nonthermal shielding on the formation of the negative hydrogen ion (H − ) by the polarization electron capture are investigated in partially ionized generalized Lorentzian plasmas. The Bohr-Lindhard method has been applied to obtain the negative hydrogen formation radius and cross section as functions of the collision energy, de Broglie wave length, Debye length, impact parameter, and spectral index of the plasma. The result shows that the nonthermal character of the plasma enhances the formation radius of the negative hydrogen, especially, for small Debye radii. It is found that the nonthermal effect increases the formation cross section of the negative hydrogen. It is also found that the maximum position of the formation cross section approaches to the collision center with an increase of the spectral index. In addition, it is found that the formation cross section significantly decreases with an increase of the Debye length, especially, for small spectral indices.

Multiple quasi-monoenergetic electron beams from laser-wakefield acceleration with spatially structured laser pulse

Energy Technology Data Exchange (ETDEWEB)

Ma, Y.; Li, M. H.; Li, Y. F.; Wang, J. G.; Tao, M. Z.; Han, Y. J.; Zhao, J. R.; Huang, K.; Yan, W. C.; Ma, J. L.; Li, Y. T. [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100080 (China); Chen, L. M., E-mail: lmchen@iphy.ac.cn [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100080 (China); Department of Physics and Astronomy and IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Li, D. Z. [Institute of High Energy Physics, CAS, Beijing 100049 (China); Chen, Z. Y. [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan 621999 (China); Sheng, Z. M. [Department of Physics and Astronomy and IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Physics, Scottish Universities Physics Alliance, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Zhang, J. [Department of Physics and Astronomy and IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China)

2015-08-15

By adjusting the focus geometry of a spatially structured laser pulse, single, double, and treble quasi-monoenergetic electron beams were generated, respectively, in laser-wakefield acceleration. Single electron beam was produced as focusing the laser pulse to a single spot. While focusing the laser pulse to two spots that are approximately equal in energy and size and intense enough to form their own filaments, two electron beams were produced. Moreover, with a proper distance between those two focal spots, three electron beams emerged with a certain probability owing to the superposition of the diffractions of those two spots. The energy spectra of the multiple electron beams are quasi-monoenergetic, which are different from that of the large energy spread beams produced due to the longitudinal multiple-injection in the single bubble.

Stochastic acceleration of electrons from multiple uncorrelated plasma waves

Science.gov (United States)

Gee, David; Michel, Pierre; Wurtele, Jonathan

2017-10-01

One-dimensional theory puts a strict limit on the maximum energy attainable by an electron trapped and accelerated by an electron plasma wave (EPW). However, experimental measurements of hot electron distributions accelerated by stimulated Raman scattering (SRS) in ICF experiments typically show a thermal distribution with temperatures of the order of the kinetic energy of the resonant EPW's (Thot mvp2 , where vp is the phase velocity of the EPW's driven by SRS) and no clear cutoff at high energies. In this project, we are investigating conditions under which electrons can be stochastically accelerated by multiple uncorrelated EPW's, such as those generated by incoherent laser speckles in large laser spots like the ones used on NIF ( mm-size), and reproduce distributions similar to those observed in experiments. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

A bottleneck model of set-specific capture.

Directory of Open Access Journals (Sweden)

Katherine Sledge Moore

Full Text Available Set-specific contingent attentional capture is a particularly strong form of capture that occurs when multiple attentional sets guide visual search (e.g., "search for green letters" and "search for orange letters". In this type of capture, a potential target that matches one attentional set (e.g. a green stimulus impairs the ability to identify a temporally proximal target that matches another attentional set (e.g. an orange stimulus. In the present study, we investigated whether set-specific capture stems from a bottleneck in working memory or from a depletion of limited resources that are distributed across multiple attentional sets. In each trial, participants searched a rapid serial visual presentation (RSVP stream for up to three target letters (T1-T3 that could appear in any of three target colors (orange, green, or lavender. The most revealing findings came from trials in which T1 and T2 matched different attentional sets and were both identified. In these trials, T3 accuracy was lower when it did not match T1's set than when it did match, but only when participants failed to identify T2. These findings support a bottleneck model of set-specific capture in which a limited-capacity mechanism in working memory enhances only one attentional set at a time, rather than a resource model in which processing capacity is simultaneously distributed across multiple attentional sets.

Alignment in double capture processes

Energy Technology Data Exchange (ETDEWEB)

Moretto-Capelle, P.; Benhenni, M.; Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A. (IRSAMC, URA CNRS 770, Univ. Paul Sabatier, 118 rte de Narbonne, 31062 Toulouse Cedex (France))

1993-06-05

The electron spectra emitted when a double capture occurs in N[sup 7+]+He and Ne[sup 8+]+He systems at 10 qkeV collisional energy, allow us to determine the angular distributions of the 3[ell]3[ell] [prime] lines through a special spectra fitting procedure which includes interferences between neighbouring states. It is found that the doubly excited states populated in double capture processes are generally aligned.

Experiences in running a complex electronic data capture system using mobile phones in a large-scale population trial in southern Nepal.

Science.gov (United States)

Style, Sarah; Beard, B James; Harris-Fry, Helen; Sengupta, Aman; Jha, Sonali; Shrestha, Bhim P; Rai, Anjana; Paudel, Vikas; Thondoo, Meelan; Pulkki-Brannstrom, Anni-Maria; Skordis-Worrall, Jolene; Manandhar, Dharma S; Costello, Anthony; Saville, Naomi M

2017-01-01

The increasing availability and capabilities of mobile phones make them a feasible means of data collection. Electronic Data Capture (EDC) systems have been used widely for public health monitoring and surveillance activities, but documentation of their use in complicated research studies requiring multiple systems is limited. This paper shares our experiences of designing and implementing a complex multi-component EDC system for a community-based four-armed cluster-Randomised Controlled Trial in the rural plains of Nepal, to help other researchers planning to use EDC for complex studies in low-income settings. We designed and implemented three interrelated mobile phone data collection systems to enrol and follow-up pregnant women (trial participants), and to support the implementation of trial interventions (women's groups, food and cash transfers). 720 field staff used basic phones to send simple coded text messages, 539 women's group facilitators used Android smartphones with Open Data Kit Collect, and 112 Interviewers, Coordinators and Supervisors used smartphones with CommCare. Barcoded photo ID cards encoded with participant information were generated for each enrolled woman. Automated systems were developed to download, recode and merge data for nearly real-time access by researchers. The systems were successfully rolled out and used by 1371 staff. A total of 25,089 pregnant women were enrolled, and 17,839 follow-up forms completed. Women's group facilitators recorded 5717 women's groups and the distribution of 14,647 food and 13,482 cash transfers. Using EDC sped up data collection and processing, although time needed for programming and set-up delayed the study inception. EDC using three interlinked mobile data management systems (FrontlineSMS, ODK and CommCare) was a feasible and effective method of data capture in a complex large-scale trial in the plains of Nepal. Despite challenges including prolonged set-up times, the systems met multiple data

Lifetime of the long-lived isomer of /sup 236/Np from. cap alpha. -,. beta. - and electron-capture decay measurements

Energy Technology Data Exchange (ETDEWEB)

Lindner, M.; Dupzyk, R.J.; Hoff, R.W.; Nagle, R.J. (California Univ., Livermore (USA). Lawrence Livermore National Lab.)

1981-01-01

The half-life of long-lived /sup 236/Np, due to ..cap alpha.., ..beta.. and electron-capture decay, was found to be 1.55 x 10/sup 5/ yr. Of all decays, 88% populate excited states in /sup 236/U and 12% populate levels in /sup 236/Pu. Lifetimes measured by growth of the ground states of /sup 236/U and /sup 236/Pu agree with values from corresponding ..gamma.. de-excitations in these daughter nuclei. Therefore, nearly all the electron-capture decays populate the 6/sup +/ level of the ground-state band in /sup 236/U. Similarly, essentially all the ..beta../sup -/ decay populates an analogous 6/sup +/ level in /sup 236/Pu, which de-excites through a previously unreported transition of 158.3 keV. If a very week ..gamma..-ray at 894 keV can be ascribed to a level in /sup 232/U populated by ..beta.. decay of /sup 232/Pa, its existence establishes a 0.2% ..cap alpha..-branching decay in /sup 236/Np.

Iodide- and bromide-specific electron-capture/photodetachment-modulated detector for the trace analysis of halocarbon mixtures

International Nuclear Information System (INIS)

Mock, R.S.; Grimsrud, E.P.

1988-01-01

The use of photodetachment (PD) of electrons from negative ions in a pulsed electron capture detector (ECD) is described. By passing a chopped light beam through the ECD and amplification of the modulated component of the ECD signal, the photodetachment-modulated (PDM) pulsed ECD can be made to respond selectively and sensitively to iodine- containing hydrocarbons alone, or to iodine- and bromine-containing hydrocarbons in the presence of chlorinated hydrocarbons. The detection limit of the iodide/bromide-specific mode of the PDM-ECD to CH 3 I is shown to be competitive with that of the normal mode of the pulsed ECD. This detection mode of the ECD is shown to be of great assistance in the gas chromatographic analysis of organobromides and organoiodides in complex mixtures which contain a large number of organochlorides

Electronic health records: what does your signature signify?

Directory of Open Access Journals (Sweden)

Victoroff MD Michael S

2012-08-01

Full Text Available Abstract Electronic health records serve multiple purposes, including clinical communication, legal documentation, financial transaction capture, research and analytics. Electronic signatures attached to entries in EHRs have different logical and legal meanings for different users. Some of these are vestiges from historic paper formats that require reconsideration. Traditionally accepted functions of signatures, such as identity verification, attestation, consent, authorization and non-repudiation can become ambiguous in the context of computer-assisted workflow processes that incorporate functions like logins, auto-fill and audit trails. This article exposes the incompatibility of expectations among typical users of electronically signed information.

Preclinical studies on gadolinium neutron capture therapy

International Nuclear Information System (INIS)

Akine, Yasuyuki

1994-01-01

Gadolinium neutron capture therapy is based on radiations (photons and electrons) produced in the tumor by a nuclear reaction between gadolinium and lower-energy neutrons. Studies with Chinese hamster cells have shown that the radiation effect resulting from gadolinium neutron capture reactions is mostly of low LET and that released electrons are the significant component in the over-all dose. Biological dosimetry revealed that the dose does not seem to increase in proportion to the gadolinium concentration, leading to a conclusion that there is a range of gadolinium concentrations most efficient for gadolinium neutron capture therapy. The in vivo studies with transplantable tumors in mice and rabbits have revealed that close contact between gadolinium and the cell is not necessarily required for cell inactivation and that gadolinium delivery selective to tumors is crucial. The results show that the potential of gadolinium neutron capture therapy as a therapeutic modality appears very promising. (author)

Electron-capture delayed fission properties of neutron-deficient einsteinium nuclei

Energy Technology Data Exchange (ETDEWEB)

Shaughnessy, Dawn A. [Univ. of California, Berkeley, CA (United States)

2000-01-01

Electron-capture delayed fission (ECDF) properties of neutron-deficient einsteinium isotopes were investigated using a combination of chemical separations and on-line radiation detection methods. ²⁴²Es was produced via the ²³³U(¹⁴N,5n)²⁴²Es reaction at a beam energy of 87 MeV (on target) in the lab system, and was found to decay with a half-life of 11 ± 3 seconds. The ECDF of ²⁴²Es showed a highly asymmetric mass distribution with an average pre-neutron emission total kinetic energy (TKE) of 183 ± 18 MeV. The probability of delayed fission (P_DF) was measured to be 0.006 ± 0.002. In conjunction with this experiment, the excitation functions of the ²³³U(¹⁴N,xn)^247-xEs and ²³³U^{(15N,xn)248-x}Es reactions were measured for ²⁴³Es, ²⁴⁴Es and ²⁴⁵Es at projectile energies between 80 MeV and 100 MeV.

Single electron capture differential cross section in H+ + He collisions at intermediate and high collision energies

International Nuclear Information System (INIS)

Abufager, P N; Fainstein, P D; MartInez, A E; Rivarola, R D

2005-01-01

The generalized continuum distorted wave-eikonal initial state (CDW-EIS II) approximation is employed to study differential cross sections (DCS) for single electron capture in H + + He collisions at intermediate and high energies. Present results are compared with theoretical calculations obtained using the previous CDW-EIS formulation in order to show the importance of the description of the bound and continuum target states in the entrance and exit channels, respectively. Both DCS are also shown together with other theoretical results and with experimental data

Isotope separation by photoselective dissociative electron

International Nuclear Information System (INIS)

Stevens, C.G.

1978-01-01

A method of separating isotopes based on photoselective electron capture dissociation of molecules having an electron capture cross section dependence on the vibrational state of the molecule is described. A molecular isotope source material is irradiated to selectively excite those molecules containing a desired isotope to a predetermined vibrational state having associated therewith an electron capture energy region substantially non-overlapping with the electron capture energy ranges associated with the lowest vibration states of the molecules. The isotope source is also subjected to electrons having an energy corresponding to the non-overlapping electron capture region whereby the selectively excited molecules preferentially capture electrons and dissociate into negative ions and neutrals. The desired isotope may be in the negative ion product or in the neutral product depending upon the mechanism of dissociation of the particular isotope source used. The dissociation product enriched in the desired isotope is then separated from the reaction system by conventional means. Specifically, 235 UF 6 is separated from a UF 6 mixture by selective excitation followed by dissociative electron capture into 235 UF 5 - and F

Comparison of Ring-Buffer-Based Packet Capture Solutions

Energy Technology Data Exchange (ETDEWEB)

Barker, Steven Andrew [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2015-10-01

Traditional packet-capture solutions using commodity hardware incur a large amount of overhead as packets are copied multiple times by the operating system. This overhead slows sensor systems to a point where they are unable to keep up with high bandwidth traffic, resulting in dropped packets. Incomplete packet capture files hinder network monitoring and incident response efforts. While costly commercial hardware exists to capture high bandwidth traffic, several software-based approaches exist to improve packet capture performance using commodity hardware.

The Bells' Capture note TH-3054-CERN

Energy Technology Data Exchange (ETDEWEB)

Hartouni, Ed P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2014-01-29

This document revisits the paper by M. Bell and J. S. Bell “Capture of Cooling Electrons by Cool Protons” TH-3054-CERN (March 30, 1981). I expand the treatment to include e⁺e^- capture.

Capturing device for radioactive corrosion products

International Nuclear Information System (INIS)

Ono, Kiyoshi.

1987-01-01

Purpose: To render the flow channel area uniform for each of coolants over the entire capturing device and reduce the corrosion of capturing materials due to coolants. Constitution: Most of radioactivity caused by radioactive corrosion products are due to Mn-54 radioactive nuclides and it has been known that the nuclides are readily deposited to the surface of nickel material in sodium at high temperature. It is difficult in a conventional capturing device constituted by winding a nickel plate fabricated with protrusions in a multiple-coaxial configuration, that the flow channel area is reduced in a portion of the flow channel and it is difficult to make the flow of the coolants uniform. In view of the above, by winding a nickel plate having a plurality of protrusions at the surface formed integrally by way of an electrolytic process into a multiple-coaxial or spiral shape, those having high resistance to the coolant corrosion can be obtained. (Takahashi, M.)

Differential charge transfer and continuum electron capture studies for ions in atomic hydrogen. Final report, August 1, 1979-September 31, 1983

International Nuclear Information System (INIS)

Sellin, I.A.; Elston, S.B.

1983-01-01

A final technical narrative is given of progress and results obtained during the period August 1, 1979 through September 30, 1983 in a project designed to test existing theories of electron capture to continuum states of fully stripped nuclei traversing atomic hydrogen targets. 5 references

State-selective electron capture in collisions of ground and metastable O2+ ions with H(1s)

International Nuclear Information System (INIS)

Cabello, C N; Errea, L F; Fernandez, L; Mendez, L; Macias, A; Rabadan, I; Riera, A

2003-01-01

An ab initio calculation of the electron capture cross sections for collisions of ground and metastable states of O 2+ with H(1s) is presented. For impact energies between 0.125 and 3.4 keV amu -1 , we find good agreement between the cross sections from the ground state ion with the mixed beam experimental data of Phaneuf et al (Phaneuf A, Alvarez I, Meyer F W and Crandall D H 1982 Phys. Rev. A 26 1892)

Double capture in the O/sup 8+/ + He collision investigated by electron spectroscopy (80 keV, 10 deg)

Energy Technology Data Exchange (ETDEWEB)

Moretto-Capelle, P.; Benoit-Cattin, P.; Bordenave-Montesquieu, A.; Boudjema, M.; Gleizes, A.; Oza, D.H.; Dousson, S.; Hitz, D.

1989-01-28

Double capture into (3,n) autoionising states of O/sup 6+/ is observed in the O/sup 8+/ + He collision system by electron spectroscopy at 80 keV, 10/sup 0/. A comparison of the experimental results with theoretical positions and lifetimes allows the (3,3) states as well as three groups of (3,4) states to be identified. The present experimental findings are compared with earlier data for the N/sup 7+/ + He and Ne/sup 8+/(1s/sup 2/) + He systems. The influence of the core of the multicharged ion is studied by examining the O/sup 8+/ and Ne/sup 8+/(1s/sup 2/) results. The total double capture cross section is found to be large and it is compared with available experimental and theoretical data.

PbSnTe:In compound: Electron capture levels, galvanomagnetic properties, and THz sensitivity

Energy Technology Data Exchange (ETDEWEB)

Ishchenko, D. V., E-mail: miracle4348@gmail.com; Klimov, A. E.; Shumsky, V. N.; Epov, V. S. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

2016-12-15

A model of the Pb{sub 1–x}Sn{sub x}Te:In compound, based on concepts of the theory of disordered systems is considered. The temperature dependences of the Fermi-level position and carrier concentration are calculated depending on the indium doping level and are compared with experimental data. The transient current–voltage characteristics are calculated in the mode of injection from the contact and current limitation by space charge at various voltage-variation rates. The data obtained are compared with the experiments. It is demonstrated that the shape of the characteristics is controlled by the parameters of electron capture at localized states. Photocurrent relaxation in a magnetic field is studied, and the mechanism of such relaxation is discussed under the assumption of the magnetic freezing of carriers.

Multiple scattering of slow muons in an electron gas

International Nuclear Information System (INIS)

Archubi, C.D.; Arista, N.R.

2017-01-01

A comparative study of the angular dispersion of slow muons in an electron gas is performed using 3 dielectric models which represent the case of metals (Lindhard model for a free electron gas) and the cases of semiconductors and insulators (Levine and Louie model and Brandt and Reinheimer model for systems with a band gap) and a non-linear model for both cases at very low velocities. The contribution of collective electronic excitations according to the dielectric model are found to be negligible. The results from the calculation using Lindhard expressions for the angular half width are consistent with the result of a multiple scattering model. In particular, the effects produced by the band gap of the material are analyzed in detail. Finally, as the recoil effect is negligible, there is an almost exact scaling, for a given velocity, between the proton and the muon results. (authors)

'Mathematical model of K Capture and its implications'

International Nuclear Information System (INIS)

Angus, Andrew C.

2000-01-01

The mechanism of K Capture, the nuclear absorption of electron in the K shell, as induced by electricity, is explained in this article. Furthermore, a mathematical model of K Capture is formulated. Then, K Capture is applied to explain the negative results obtained by Steven Jones and the positive results obtained by Pons-Fleischmann in Deuterium Oxide Electrolysis Experiments. The most important implication of K Capture is the possibility of obtaining nuclear energy by fusion at low temperature from heavy water

Correlated electron capture in the impact parameter and final projectile charge-state dependence of ECC cusp production in 0.53 MeV u-1 F8+ + Ne

International Nuclear Information System (INIS)

Skutlartz, A.; Hagmann, S.; Schmidt-Boecking, H.

1988-01-01

The impact parameter dependence of ECC cusp electron production in collisions of fast, highly charged ions with atoms is investigated by measuring the scattered projectiles in coincidence with cusp electrons emitted at 0 0 with respect to the beam axis. The absolute probabilities for ECC cusp production show a maximum at b ≅ 0.10 au, decrease strongly for smaller impact parameters and more gently toward larger impact parameters. In addition the final charge state of the scattered projectile is also determined simultaneously for each collision event. The probabilities, as a function of the projectile final charge state, are large for the case where at least one or more electrons are simultaneously captured into bound states of the projectile, but are surprisingly small for collisions in which a projectile did not capture an electron into a bound state. (author)

Mass measurements of neutron rich isotopes in the Fe region and electron capture processes in neutron star crusts

International Nuclear Information System (INIS)

Estrade, Alfredo; Matos, M.; Schatz, Hendrik; Amthor, A.M.; Beard, Mary; Brown, Edward; Bazin, D.; Becerril, A.; Elliot, T.; Gade, A.; Galaviz, D.; Gupta, Sanjib; Hix, William Raphael; Lau, Rita; Moeller, Peter; Pereira, J.; Portillo, M.; Rogers, A.M.; Shapira, Dan; Smith, E.; Stolz, A.; Wallace, M.; Wiescher, Michael

2011-01-01

Experimental knowledge of nuclear masses of exotic nuclei is important for understanding nuclear structure far from the valley of stability, and as a direct input into astrophysical models. Electron capture processes in the crust of accreting neutron stars have been proposed as a heat source that can affect the thermal structure of the star. Nuclear masses of very neutron-rich nuclides are necessary inputs to model the electron capture process. The time-of-flight (TOF) mass measurement technique allows measurements on very short-lived nuclei. It has been effectively applied using the fast fragment beams produced at the National Superconducting Cyclotron Lab (NSCL) to reach masses very far from stability. Measurements were performed for neutron-rich isotopes in the region of the N=32 and N=40 subshells, which coincides with the mass range of carbon superburst ashes. We discuss reaction network calculations performed to investigate the impact of our new measurements and to compare the effect of using different global mass models in the calculations. It is observed that the process is sensitive to the differences in the odd-even mass staggering predicted by the mass models, and our new result for 66Mn has a significant impact on the distribution of heat sources in the crust.

Electron capture on 20Ne and the ultimate fate of stars in the mass range 8-10 M⊙

International Nuclear Information System (INIS)

Kirsebom, Oliver S.; Cederkall, Joakim; Jenkins, David G.; Joshi, Pankaj; Julin, Rauno; Kankainen, Anu; Trzaska, Wladyslaw H.; Kibedi, Tibor; Tengblad, Olof

2016-01-01

Knowledge of the electron-capture rate on 20 Ne is of critical importance to understand the final evolution of stars in the mass range 8-10M⊙. A recent study has highlighted the importance of the second-forbidden transition between the ground states of 20 Ne and 20 F, which is believed to dominate the capture rate in an important temperature-density range. The strength of this transition is, however, not well constrained, neither experimentally nor theoretically, making an experimental determination highly desirable. The transition strength can be determined from the branching ratio of the inverse transition in the decay of 20 F, for which the experimental upper limit is 10 -5 , while the most recent theoretical prediction is 1.3 x 10 -6 . To facilitate an experimental determination of the branching ratio we are refurbishing an intermediate-image magnetic spectrometer capable of focusing 7 MeV electrons, and designing a scintillator detector surrounded by an active cosmic-ray veto shield, which will serve as an energy- dispersive device at the focal plane. In this contribution, GEANT4 simulations of the expected performance of the setup will be presented and the astrophysical motivation for the experiment will be discussed. (author)

Total cross-sections for single electron capture from H, He and H2 targets by impact of Be4+ and B5+ ions

International Nuclear Information System (INIS)

Busnengo, H.F.; Rivarola, R.D.; Universidad Nacional de Rosario; Rosario Univ. Nacional

1996-01-01

Single electron capture from H, He and H 2 targets by impact of Be 4+ and B 5+ projectiles is studied for intermediate and high collision energies. Total cross-sections are calculated using the continuum distorted wave-eikonal final state model. Theoretical results corresponding to capture to selective final bound states and to all final states are presented for impact energies ranging from 50 keV/amu to 3 MeV/amu. A comparison with available experimental data is also shown. (orig.)

Electron capture detection of sulphur gases in carbon dioxide at the parts-per-billion level

International Nuclear Information System (INIS)

Pick, M.E.

1979-01-01

A gas chromatograph with an electron capture detector has been used to determine sulphur gases in CO 2 at the parts-per-billion level, with particular application to the analysis of coolant from CO 2 cooled nuclear reactors. For COS, CS 2 , CH 3 SH, H 2 S and (CH 3 ) 2 S 2 the detector has a sensitivity comparable with the more commonly used flame photometric detector, but it is much less sensitive towards (CH 3 ) 2 S and thiophene. In addition, the paper describes a simple method for trapping sulphur gases which might enable detection of sub parts-per-billion levels of sulphur compounds. (Auth.)

Comparison between the mechanical and radiative electron-capture processes at high energies

International Nuclear Information System (INIS)

Gonzalez, A.D.; Miraglia, J.E.

1984-01-01

The ground-state--ground-state mechanical and radiative electron-capture processes are studied at very high, but not relativistic, projectile velocities. Three-body calculations were carried out with use of the continuum distorted-wave theoretical method for both processes. Total cross sections and final-atom angular distributions were computed, and the importance of each mechanism examined. For total cross sections, the numerical results reaffirm that the radiative process is the predominant mechanism at very high projectile energies. For a given incident charge, the range of projectile energies in which the nonrelativistic radiative mechanism is the most important decreases as the target charge increases. It is found that the radiative mechanism produces a very sharp final-atom angular distribution in the forward direction. When both processes, the radiative and mechanical, give the same total cross section, the calculations show that the radiative differential cross section in the forward direction is almost 2 orders of magnitude larger than the mechanical one

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)

Gene-specific characterization of human histone H2B by electron capture dissociation.

Science.gov (United States)

Siuti, Nertila; Roth, Michael J; Mizzen, Craig A; Kelleher, Neil L; Pesavento, James J

2006-02-01

The basis set of protein forms expressed by human cells from the H2B gene family was determined by Top Down Mass Spectrometry. Using Electron Capture Dissociation for MS/MS of H2B isoforms, direct evidence for the expression of unmodified H2B.Q, H2B.A, H2B.K/T, H2B.J, H2B.E, H2B.B, H2B.F, and monoacetylated H2B.A was obtained from asynchronous HeLa cells. H2B.A was the most abundant form, with the overall expression profile not changing significantly in cells arrested in mitosis by colchicine or during mid-S, mid-G2, G2/M, and mid-G1 phases of the cell cycle. Modest hyperacetylation of H2B family members was observed after sodium butyrate treatment.

Interaction of multicharged ions with molecules (CO{sub 2}, C{sub 60}) by coincident electron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A. [Universite Paul Sabatier, Toulouse (France). Lab. CAR-IRSAMC

2001-07-01

First results for the investigation of electron capture processes in collisions between multicharged ions and molecule targets using electron spectroscopy in coincidence with charged fragments, are presented. It is shown that a much more detailed investigation of the capture reaction can be achieved using molecular instead of heavy atomic targets provided that an analysis of the target dissociation is made. The collisional systems {sup 18}O{sup 8+}+Ar, CO{sub 2} and C{sub 60} have been studied at 80 keV. Non coincident electron spectra as well as first results of double or triple coincidence experiments are discussed. Kinetic energy distributions of the C{sub n}{sup +} fragments (n=1 to 8) produced in multiple capture processes from C{sub 60} target are given. A detailed investigation of the double capture process with CO{sub 2} molecule allows the measurement of kinetic energy release distributions (KERD) which characterize the dissociation of CO{sub 2}{sup 2+} molecular ions; our results are found to be very similar to those measured in double photoionisation experiments. (orig.)

Capture from pair production as a beam loss mechanism for heavy ions at RHIC

International Nuclear Information System (INIS)

Feinberg, B.; Belkacem, A.; Claytor, N.; Dinneen, T.; Gould, H.

1997-05-01

Electron capture from electron-positron pair production is predicted to be a major source of beam loss for the heaviest ions at RHIC. Achieving the highest luminosity thus requires an understanding of the capture process. The authors report measurements of this process at Brookhaven National Laboratory's AGS using 10.8 GeV/nucleon Au 79+ projectiles on Au targets. Capture from pair production is a process in which the very high electromagnetic field involved in the collision of two relativistic heavy ions results in the production of an electron-positron pair with the capture of the electron by one of the ions. There are many theoretical papers published on capture from pair production with discrepancies between predicted cross sections. The experimental results are compared to theory and to previous experiments at 1 GeV/nucleon. The implications of extrapolations to RHIC energies are presented

Capturing pan-Canadian Primary Health Care indicator data using multiple approaches for data collection.

Science.gov (United States)

Walker, Vicky; Sullivan-Taylor, Patricia; Webster, Greg; Macphail, Judith

2009-01-01

The Canadian Institute for Health Information (CIHI), in collaboration with diverse stakeholders, led the development of pan-Canadian indicators to measure primary health care. In 2006, CIHI released a set of 105 pan-Canadian Primary Health Care (PHC) indicators that were developed with the assistance of national, provincial and territorial representatives, clinicians and researchers. Additionally, data gaps were identified in a series of reports. In 2006 and 2007, CIHI assessed options for closing the data gaps so that the indicators could be measured and reported. CIHI then began a program to build the data infrastructure needed for the PHC indicators. The program included the development of content standards for electronic medical records, a prototype of a voluntary reporting system, enhancements to surveys, and the development of reports. In 2006, fewer than 10% of the 105 indicators could be calculated with existing data sources. Now, four projects have begun and over 50% of the indicators are being captured. Important relationships have been established with key collaborators. These relationships will lead to the development of a reporting system prototype and to the refinement of PHC indicators and electronic medical record (EMR) content standards. The project for pan-Canadian PHC indicators has encouraged consultation and synergy. It has motivated CIHI to establish an information program to fill data gaps and to make PHC indicators available.

Tunable valley polarization by a gate voltage when an electron tunnels through multiple line defects in graphene.

Science.gov (United States)

Liu, Zhe; Jiang, Liwei; Zheng, Yisong

2015-02-04

By means of an appropriate wave function connection condition, we study the electronic structure of a line defect superlattice of graphene with the Dirac equation method. We obtain the analytical dispersion relation, which can simulate well the tight-binding numerical result about the band structure of the superlattice. Then, we generalize this theoretical method to study the electronic transmission through a potential barrier where multiple line defects are periodically patterned. We find that there exists a critical incident angle which restricts the electronic transmission through multiple line defects within a specific incident angle range. The critical angle depends sensitively on the potential barrier height, which can be modulated by a gate voltage. As a result, non-trivial transmissions of K and K' valley electrons are restricted, respectively, in two distinct ranges of the incident angle. Our theoretical result demonstrates that a gate voltage can act as a feasible measure to tune the valley polarization when electrons tunnel through multiple line defects.

Spin-polarized electron capture for the Na+3He2+ system at a 3He2+ impact energy of 5.33--9.33 keV/amu

International Nuclear Information System (INIS)

Tanaka, M.; Shimakura, N.; Ohshima, T.; Katori, K.; Fujiwara, M.; Ogata, H.; Kondo, M.

1994-01-01

3 He + atomic polarizations following the spin-polarized electron capture process for the N rvec a(3s)+ 3 He 2+ system were measured at 3 He 2+ impact energies from 5.33 to 9.33 keV/amu. The magnitude of the 3 He + atomic polarizations was deduced from the 3 He + nuclear polarization measured by means of beam-foil spectroscopy. The observed polarization transfer coefficient P T defined by the ratio of the 3 He + atomic polarization to the sodium one showed a pronounced reduction from unity, which was qualitatively explained by the prediction of a simple cascade photon decay model. Evidence for a further reduction of P T from the above model and a possible impact energy dependence of P T suggested an excessive depolarization due to the presence of the collision alignment parameter A 0 col of 3 He + formed by the electron capture process. In order to see this more closely, the observed P T 's were examined theoretically using the semiclassical impact parameter method, in which an 18-state molecular expansion was employed, and atomic-type electron translation effects were rigorously taken into account. Ensuring that both the absolute values and the impact energy dependence of the observed capture cross sections were remarkably well reproduced by the calculations in which the states up to 4f in 3 He + were introduced, it was demonstrated that the calculated results for P T qualitatively reproduced not only the absolute values of the observed P T 's but also their gentle decrease with increasing impact energy. Production of nuclear polarizations resulting from the polarized electron capture processes between multicharged heavy ions and alkaline-earth-metal atoms is an example of one use of the future project of universal polarized heavy-ion sources

Exploratory investigations of hypervelocity intact capture spectroscopy

Science.gov (United States)

Tsou, P.; Griffiths, D. J.

1993-01-01

The ability to capture hypervelocity projectiles intact opens a new technique available for hypervelocity research. A determination of the reactions taking place between the projectile and the capture medium during the process of intact capture is extremely important to an understanding of the intact capture phenomenon, to improving the capture technique, and to developing a theory describing the phenomenon. The intact capture of hypervelocity projectiles by underdense media generates spectra, characteristic of the material species of projectile and capture medium involved. Initial exploratory results into real-time characterization of hypervelocity intact capture techniques by spectroscopy include ultra-violet and visible spectra obtained by use of reflecting gratings, transmitting gratings, and prisms, and recorded by photographic and electronic means. Spectrometry proved to be a valuable real-time diagnostic tool for hypervelocity intact capture events, offering understanding of the interactions of the projectile and the capture medium during the initial period and providing information not obtainable by other characterizations. Preliminary results and analyses of spectra produced by the intact capture of hypervelocity aluminum spheres in polyethylene (PE), polystyrene (PS), and polyurethane (PU) foams are presented. Included are tentative emission species identifications, as well as gray body temperatures produced in the intact capture process.

Multiplicity-Vertex Detector Electronics Development for Heavy-Ion Detectors

Energy Technology Data Exchange (ETDEWEB)

Britton, C.L., Jr.; Bryan, W.L.; Emery, M.S. [and others

1995-12-31

This paper presents the electronics work performed to date for the Multiplicity-Vertex Detector (MVD) for the PHENIX collaboration at RHIC. The detector consists of approximately 34,000 channels of both silicon strips and silicon pads. The per-channel signal processing chain consists of a pre-amplifier gain stage, a current mode summed multiplicity discriminator, a 64 deep analog memory (simultaneous read/write), an analog correlator, and a 10-bit microsecs ADC. The system controller or Heap Manager, supplies all timing control, data buffering, and data formatting for a single 256-channel multi-chip module (MCM). Each chip set is partitioned into 32-channel sets. Prototype performance for the various blocks will be presented as well as the ionizing radiation damage performance of the 1.2 mu nwell CMOS process used for fabrication.

Water Capture Device Signal Integration Board

Science.gov (United States)

Chamberlin, Kathryn J.; Hartnett, Andrew J.

2018-01-01

I am a junior in electrical engineering at Arizona State University, and this is my second internship at Johnson Space Center. I am an intern in the Command and Data Handling Branch of Avionics Division (EV2), my previous internship was also in EV2. During my previous internship I was assigned to the Water Capture Device payload, where I designed a prototype circuit board for the electronics system of the payload. For this internship, I have come back to the Water Capture Device project to further the work on the electronics design I completed previously. The Water Capture Device is an experimental payload to test the functionality of two different phase separators aboard the International Space Station (ISS). A phase separator sits downstream of a condensing heat exchanger (CHX) and separates the water from the air particles for environmental control on the ISS. With changing CHX technology, new phase separators are required. The goal of the project is to develop a test bed for the two phase separators to determine the best solution.

Phantom experiment of depth-dose distributions for gadolinium neutron capture therapy

International Nuclear Information System (INIS)

Matsumoto, T.; Kato, K.; Sakuma, Y.; Tsuruno, A.; Matsubayashi, M.

1993-01-01

Depth-dose distributions in a tumor simulated phantom were measured for thermal neutron flux, capture gamma-ray and internal conversion electron dose rates for gadolinium neutron capture therapy. The results show that (i) a significant dose enhancement can be achieved in the tumor by capture gamma-rays and internal conversion electrons but the dose is mainly due to capture gamma-rays from the Gd(n, γ) reactions, therefore, is not selective at the cellular level, (ii) the dose distribution was a function of strongly interrelated parameters such as gadolinium concentrations, tumor site and neutron beam size (collimator aperture size), and (iii) the Gd-NCT by thermal neutrons appears to be a potential for treatment of superficial tumor. (author)

Small Particles Intact Capture Experiment (SPICE)

Science.gov (United States)

Nishioka, Ken-Ji; Carle, G. C.; Bunch, T. E.; Mendez, David J.; Ryder, J. T.

1994-01-01

The Small Particles Intact Capture Experiment (SPICE) will develop technologies and engineering techniques necessary to capture nearly intact, uncontaminated cosmic and interplanetary dust particles (IDP's). Successful capture of such particles will benefit the exobiology and planetary science communities by providing particulate samples that may have survived unaltered since the formation of the solar system. Characterization of these particles may contribute fundamental data to our knowledge of how these particles could have formed into our planet Earth and, perhaps, contributed to the beginnings of life. The term 'uncontaminated' means that captured cosmic and IDP particles are free of organic contamination from the capture process and the term 'nearly intact capture' means that their chemical and elemental components are not materially altered during capture. The key to capturing cosmic and IDP particles that are organic-contamination free and nearly intact is the capture medium. Initial screening of capture media included organic foams, multiple thin foil layers, and aerogel (a silica gel); but, with the exception of aerogel, the requirements of no contamination or nearly intact capture were not met. To ensure no contamination of particles in the capture process, high-purity aerogel was chosen. High-purity aerogel results in high clarity (visual clearness), a useful quality in detection and recovery of embedded captured particles from the aerogel. P. Tsou at the Jet Propulsion Laboratory (JPL) originally described the use of aerogel for this purpose and reported laboratory test results. He has flown aerogel as a 'GAS-can Lid' payload on STS-47 and is evaluating the results. The Timeband Capture Cell Experiment (TICCE), a Eureca 1 experiment, is also flying aerogel and is scheduled for recovery in late April.

Observation of electron multiplication in liquid xenon with a microstrip plate

International Nuclear Information System (INIS)

Policarpo, A.P.L.; Geltenbort, P.; Ferreira Marques, R.; Araujo, H.; Fraga, F.; Alves, M.A.; Fonte, P.; Lima, E.P.; Fraga, M.M.; Salete Leite, M.; Silander, K.; Onofre, A.; Pinhao, J.M.

1995-01-01

We report here on the observation of electron multiplication in liquid xenon in a microstrip chamber with an amplification factor of the order of 10. The measurements were carried out at a temperature between 208 and 215 K (liquid density of about 2.7 g/cm 3 ). (orig.)

Origin of Hund's multiplicity rule in quasi-two-dimensional two-electron quantum dots

International Nuclear Information System (INIS)

Sako, Tokuei; Paldus, Josef; Diercksen, Geerd H. F.

2010-01-01

The origin of Hund's multiplicity rules has been studied for a system of two electrons confined by a quasi-two-dimensional harmonic-oscillator potential by relying on a full configuration interaction wave function and Cartesian anisotropic Gaussian basis sets. In terms of appropriate normal-mode coordinates the wave function factors into a product of the center-of-mass and the internal components. The 1 Π u singlet state and the 3 Π u triplet state represent the energetically lowest pair of states to which Hund's multiplicity rule applies. They are shown to involve excitations into different degrees of freedom, namely, into the center-of-mass angular mode and the internal angular mode for the singlet and triplet states, respectively. The presence of an angular nodal line in the internal space allows then the triplet state to avoid the singularity in the electron-electron interaction potential, leading to the energy lowering of the triplet state relative to its counterpart singlet state.

Fluorescence excitation involving multiple electron transition states of N{sub 2} and CO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Wu, C.Y.R.; Chen, F.Z.; Hung, T.; Judge, D.L. [Univ. of Southern California, Los Angeles, CA (United States)

1997-04-01

The electronic states and electronic structures of N{sub 2} and CO{sub 2} in the 8-50 eV energy region have been studied extensively both experimentally and theoretically. In the energy region higher than 25 eV there exists many electronic states including multiple electron transition (MET) states which are responsible for producing most of the dissociative photoionization products. The electronic states at energies higher than 50 eV have been mainly determined by Auger spectroscopy, double charge transfer, photofragment spectroscopy and ion-ion coincidence spectroscopy. The absorption and ionization spectra of these molecules at energies higher than 50 eV mainly show a monotonic decrease in cross section values and exhibit structureless features. The decay channels of MET and Rydberg (or superexcited) states include autoionization, ionization, dissociative ionization, predissociation, and dissociation while those of single ion and multiple ion states may involve predissociation. and dissociation processes. The study of fluorescence specifically probes electronically excited species resulting from the above-mentioned decay channels and provides information for understanding the competition among these channels.

Exploring the use of tablet computer-based electronic data capture system to assess patient reported measures among patients with chronic kidney disease: a pilot study.

Science.gov (United States)

Wong, Dorothy; Cao, Shen; Ford, Heather; Richardson, Candice; Belenko, Dmitri; Tang, Evan; Ugenti, Luca; Warsmann, Eleanor; Sissons, Amanda; Kulandaivelu, Yalinie; Edwards, Nathaniel; Novak, Marta; Li, Madeline; Mucsi, Istvan

2017-12-06

Collecting patient reported outcome measures (PROMs) via computer-based electronic data capture system may improve feasibility and facilitate implementation in clinical care. We report our initial experience about the acceptability of touch-screen tablet computer-based, self-administered questionnaires among patients with chronic kidney disease (CKD), including stage 5 CKD treated with renal replacement therapies (RRT) (either dialysis or transplant). We enrolled a convenience sample of patients with stage 4 and 5 CKD (including patients on dialysis or after kidney transplant) in a single-centre, cross-sectional pilot study. Participants completed validated questionnaires programmed on an electronic data capture system (DADOS, Techna Inc., Toronto) on tablet computers. The primary objective was to evaluate the acceptability and feasibility of using tablet-based electronic data capture in patients with CKD. Descriptive statistics, Fischer's exact test and multivariable logistic regression models were used for data analysis. One hundred and twenty one patients (55% male, mean age (± SD) of 58 (±14) years, 49% Caucasian) participated in the study. Ninety-two percent of the respondents indicated that the computer tablet was acceptable and 79% of the participants required no or minimal help for completing the questionnaires. Acceptance of tablets was lower among patients 70 years or older (75% vs. 95%; p = 0.011) and with little previous computer experience (81% vs. 96%; p = 0.05). Furthermore, a greater level of assistance was more frequently required by patients who were older (45% vs. 15%; p = 0.009), had lower level of education (33% vs. 14%; p = 0.027), low health literacy (79% vs. 12%; p = 0.027), and little previous experience with computers (52% vs. 10%; p = 0.027). Tablet computer-based electronic data capture to administer PROMs was acceptable and feasible for most respondents and could therefore be used to systematically assess PROMs

Electronic structure of single- and multiple-shell carbon fullerenes

International Nuclear Information System (INIS)

Lin, Y.; Nori, F.

1994-01-01

We study the electronic states of giant single-shell and the recently discovered nested multiple-shell carbon fullerenes within the tight-binding approximation. We use two different approaches, one based on iterations and the other on symmetry, to obtain the π-state energy spectra of large fullerene cages: C 240 , C 540 , C 960 , C 1500 , C 2160 , and C 2940 . Our iteration technique reduces the size of the problem by more than one order of magnitude (factors of ∼12 and 20), while the symmetry-based approach reduces it by a factor of 10. We also find formulas for the highest occupied and lowest unoccupied molecular orbital energies of C 60n 2 fullerenes as a function of n, demonstrating a tendency towards a metallic regime for increasing n. For multiple-shell fullerenes, we analytically obtain the eigenvalues of the intershell interaction

Review of fission produce capture measurements at the Oak Ridge Electron Laser Accelerator (ORELA)

International Nuclear Information System (INIS)

Larson, D.C.; Macklin, R.L.

1992-01-01

The 40-meter capture system of R.L. Macklin at ORELA has been used to measure capture cross sections for over eighty isotopes between A = 75 and 161, the primary mass region of interest for fission products. This review outlines the primary features of the capture system, lists the isotopes measured and their references, and describes recent changes incorporated in the capture system

One-electron capture into Li-like autoionising N4+ (1s2ln'l') configurations by metastable N5+ (1s2s3S) multicharged ions in collisions with He and H2, observed by electron spectrometry at 3.4 keV amu-1

International Nuclear Information System (INIS)

Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A.

1985-01-01

One-electron capture into N 4+ (1s2ln'l') configurations, with n'=2 to 4, has been observed by electron spectrometry when a N 5+ (1s2s 3 S) multicharged ion beam encounters an He or H 2 target, at low collision velocity (upsilon=0.37 au) within single-collision conditions. Contributions of other 1s2l metastable states and of the 1s 2 ground state may be disregarded. A small indication of two-electron capture by 1s2s 3 S ions into (1s2s 3 S)3l3l' configurations is also seen. (author)

Dissociative multiple ionization of diatomic molecules by extreme-ultraviolet free-electron-laser pulses

DEFF Research Database (Denmark)

Madsen, Lars Bojer; Leth, Henriette Astrup

2011-01-01

Nuclear dynamics in dissociative multiple ionization processes of diatomic molecules exposed to extreme-ultraviolet free-electron-laser pulses is studied theoretically using the Monte Carlo wave packet approach. By simulated detection of the emitted electrons, the model reduces a full propagation...... of the system to propagations of the nuclear wave packet in one specific electronic charge state at a time. Suggested ionization channels can be examined, and kinetic energy release spectra for the nuclei can be calculated and compared with experiments. Double ionization of O2 is studied as an example, and good...

Electron spectroscopy in the fundamental process of electron-nucleus bremsstrahlung

International Nuclear Information System (INIS)

Hillenbrand, Pierre-Michel

2013-07-01

Within the scope of this thesis the fundamental process of electron-nucleus bremsstrahlung was studied in inverse kinematics at the Experimental Storage Ring ESR at GSI. For the system U 88+ + N 2 at 90 MeV/u it was shown, that by using inverse kinematics coincidence measurements between the scattered electron and the emitted photon can be performed for the case, in which the incoming electron transfers almost all of its kinetic energy onto the emitted photon. The sensitivity to the fundamental process could be achieved by measuring triple differential cross sections as a function of the emission angle of the photon and the scattered electron as well as the energy of the scattered electron. The optics of the magnetic electron spectrometer used were thoroughly revised and optimized to the experimental requirements. Analyzing different coincidences in this collision system, it was possible to determine the contributions to the electron distribution arising from radiative electron capture to the projectile continuum, nonradiative electron capture to the projectile continuum, and electron loss to the projectile continuum. The experimental results of each of these processes were compared to theoretical calculations. The electron spectra for the radiative and the nonradiative electron capture to continuum clearly reproduce the opposite asymmetry predicted by theory. Furthermore electron spectra for collisions of U 28+ with different gases were measured.

Eikonal calculation of electron-capture cross sections in collisions of H atoms with fast projectiles

International Nuclear Information System (INIS)

Ho, T.S.; Lieber, M.; Chan, F.T.

1981-01-01

We have employed the eikonal method to calculate the cross section for the capture of an electron into an arbitrary nl subshell in collisions between hydrogen atoms and fast projectiles. the projectiles were protons, C 6+ , O 8+ , and Fe 24+ . The energy ranges considered were 20--100 keV in the proton case, and 40--200 keV per nucleon in the other cases. These projectiles were selected because of their importance in fusion plasmas. For the highly charged case of Fe 24+ we found that our formulas, while exact, involved a high degree of cancellation and produced unreliable numerical results, so that a numerical integration of the penultimate formula was substituted. In the proton case agreement with recent experimental data is excellent

Determination of nitrosourea compounds in brain tissue by gas chromatography and electron capture detection.

Science.gov (United States)

Hassenbusch, S J; Colvin, O M; Anderson, J H

1995-07-01

A relatively simple, high-sensitivity gas chromatographic assay is described for nitrosourea compounds, such as BCNU [1,3-bis(2-chloroethyl)-1-nitrosourea] and MeCCNU [1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea], in small biopsy samples of brain and other tissues. After extraction with ethyl acetate, secondary amines in BCNU and MeCCNU are derivatized with trifluoroacetic anhydride. Compounds are separated and quantitated by gas chromatography using a capillary column with temperature programming and an electron capture detector. Standard curves of BCNU indicate a coefficient of variance of 0.066 +/- 0.018, a correlation coefficient of 0.929, and an extraction efficiency from whole brain of 68% with a minimum detectable amount of 20 ng in 5-10 mg samples. The assay has been facile and sensitive in over 1000 brain biopsy specimens after intravenous and intraarterial infusions of BCNU.

New approach to K-electron-capture probabilities to the 437 and 384 keV levels in the decay of /sup 133/Ba

Energy Technology Data Exchange (ETDEWEB)

Singh, K; Sahota, H S [Punjabi Univ., Patiala (India). Dept. of Physics

1983-12-01

The K-electron-capture probabilities to the 437 and 384 keV levels in the decay of /sup 133/Ba have been determined from a measurement of gamma-ray intensities in conjunction with an analysis of the K x-ray-gamma-ray sum peaks. The results are independent of fluorescence yield and detector efficiency.

Double electron capture in collisions of the helium-like ions N/sup 5+/, O/sup 6+/ and Ne/sup 8+/ with helium atoms

Energy Technology Data Exchange (ETDEWEB)

Boudjema, M.; Moretto-Capelle, P.; Bordenave-Montesquieu, A. and others

1989-03-28

A fitting procedure of 1s/sup 2/3l3l' lines observed in A/sup (z-2)+/(1s/sup 2/)+He collisions (Z = 7, 8 and 10), at 10 q keV collision energy (q = Z -2) and 10/sup 0/ observation angle, allows us to compare new theoretical positions and lifetimes, and experimental electron spectra. It is found that the spin conservation rule holds and that only singlet states are populated in these capture processes. As in N/sup 7+/ and O/sup 8+/ + He systems, capture into the highest angular momentum /sup 1/G state is favoured in O/sup 6+/ and Ne/sup 8+/ + He systems and accounts for 26% of the double capture at 10/sup 0/. In N/sup 5+/ + He, the L distribution is broader and no L value is clearly predominant.

Dynamics of RF captured cooled proton beams

International Nuclear Information System (INIS)

Kells, W.; Mills, F.

1983-01-01

In the course of electron cooling experiments at the Electron Cooling Ring (ECR) at Fermilab, several peculiar features of the longitudinal phase space of cold protons (200 MeV) captured in RF buckets were observed. Here we present the experimental facts, present a simple theory, and summarize computer simulation results which support the theory and facts

Multiple-electron removal and molecular fragmentation of CO by fast F4+ impact

International Nuclear Information System (INIS)

Ben-Itzhak, I.; Ginther, S.G.; Carnes, K.D.

1993-01-01

Multiple-electron removal from and molecular fragmentation of carbon monoxide molecules caused by collisions with 1-MeV/amu F 4+ ions were studied using the coincidence time-of-flight technique. In these collisions, multiple-electron removal of the target molecule is a dominant process. Cross sections for the different levels of ionization of the CO molecule during the collision were determined. The relative cross sections of ionization decrease with increasing number of electrons removed in a similar way as seen in atomic targets. This behavior is in agreement with a two-step mechanism, where first the molecule is ionized by a Franck-Condon ionization and then the molecular ion dissociates. Most of the highly charged intermediate states of the molecule dissociate rapidly. Only CO + and CO 2+ molecular ions have been seen to survive long enough to be detected as molecular ions. The relative cross sections for the different breakup channels were evaluated for collisions in which the molecule broke into two charged fragments as well as for collisions where only a single charged molecular ion or fragment were produced. The average charge state of each fragment resulting from CO Q+ →C i+ +O j+ breakup increases with the number of electrons removed from the molecule approximately following the relationship bar i=bar j=Q/2 as long as K-shell electrons are not removed. This does not mean that the charge-state distribution is exactly symmetric, as, in general, removing electrons from the carbon fragment is slightly more likely than removing electrons from the oxygen due to the difference in binding energy. The cross sections for molecular breakup into a charged fragment and a neutral fragment drop rapidly with an increasing number of electrons removed

Isomer shift calibration of 61Ni by lifetime variation measurements in the electron capture decay of 57Ni

International Nuclear Information System (INIS)

Devillers, M.; Ladriere, J.

1987-01-01

In the present work, differential ionization chambers are used in order to measure the difference in the electron capture decay rate of 57 Ni nuclei in several pairs of different chemical compounds. Combination of these values with the corresponding Moessbauer isomer shifts provides a reliable experimental method to determine differences in electron densities at the nucleus. This allows to calibrate the isomer shift scale of the concerned nuclide. By using 61 Ni isomer shifts given in the literature, this work leads to the first experimental determination of the 61 Ni isomer shift calibration constant α = -(1.8±0.9).10 -3 .a 0 3 mm.s -1 . This corresponds to a change in the mean-square charge radius Δ 2 > = -(7.2±3.4).10 -4 fm 2 during the 67.4 keV Moessbauer transition of 61 Ni. (orig.)

Magnetospheric Response Associated With Multiple Atmospheric Reflections of Precipitated Electrons in Aurora.

Science.gov (United States)

Khazanov, G. V.; Merkin, V. G.; Zesta, E.; Sibeck, D. G.; Grubbs, G. A., II; Chu, M.; Wiltberger, M. J.

2017-12-01

The magnetosphere and ionosphere are strongly coupled by precipitating electrons during storm times. Therefore, first principle simulations of precipitating electron fluxes are required to understand storm time variations of ionospheric conductances and related electric fields. As has been discussed by Khazanov et al. [2015 - 2017], the first step in such simulations is initiation of electron precipitation from the Earth's plasma sheet via wave particle interaction processes into both magnetically conjugate points, and the step 2 is the follow up of multiple atmospheric reflections of electron fluxes formed at the boundary between the ionosphere and magnetosphere of two magnetically conjugate points. To demonstrate this effect on the global magnetospheric response the Lyon-Fedder-Mobarry global magnetosphere model coupled with the Rice Convection Model of the inner magnetosphere has been used and run for the geomagnetic storm of 17 March 2013.

Q-Dependence of the double capture cross sections measured by electron spectroscopy at 10 qkeV (q = 4-8). Comparison with other experimental data

Energy Technology Data Exchange (ETDEWEB)

Bordenave-Montesquieu, A.; Boudjema, M.; Benoit-Cattin, P.; Gleizes, A.; Moretto-Capelle, P.

1989-01-01

The q dependence of cross sections for double capture into autoionising states has been investigated by electron spectroscopy. It is shown that they are independent of the ionic core. Our results are compared with all other available experimental data obtained at 10 qkeV collision energy.

Q-Dependence of the double capture cross sections measured by electron spectroscopy at 10 qkeV (q = 4-8). Comparison with other experimental data

International Nuclear Information System (INIS)

Bordenave-Montesquieu, A.; Boudjema, M.; Benoit-Cattin, P.; Gleizes, A.; Moretto-Capelle, P.

1989-01-01

The q dependence of cross sections for double capture into autoionising states has been investigated by electron spectroscopy. It is shown that they are independent of the ionic core. Our results are compared with all other available experimental data obtained at 10 qkeV collision energy

An optical study of multiple NEIAL events driven by low energy electron precipitation

Directory of Open Access Journals (Sweden)

J. M. Sullivan

2008-08-01

Full Text Available Optical data are compared with EISCAT radar observations of multiple Naturally Enhanced Ion-Acoustic Line (NEIAL events in the dayside cusp. This study uses narrow field of view cameras to observe small-scale, short-lived auroral features. Using multiple-wavelength optical observations, a direct link between NEIAL occurrences and low energy (about 100 eV optical emissions is shown. This is consistent with the Langmuir wave decay interpretation of NEIALs being driven by streams of low-energy electrons. Modelling work connected with this study shows that, for the measured ionospheric conditions and precipitation characteristics, growth of unstable Langmuir (electron plasma waves can occur, which decay into ion-acoustic wave modes. The link with low energy optical emissions shown here, will enable future studies of the shape, extent, lifetime, grouping and motions of NEIALs.

Multiple scattering in electron fluid and energy loss in multi-ionic targets

Energy Technology Data Exchange (ETDEWEB)

Deutsch, C., E-mail: claude.deutsch@u-psud.fr [LPGP, UParis-Sud, 91405-Orsay (France); Tahir, N.A. [GSI, 1Planck Str., 64291-Darmstadt (Germany); Barriga-Carrasco, M. [ETSII, UCastilla-la-Mancha, 13071 Ciudad-Real (Spain); Ceban, V. [LPGP, UParis-Sud, 91405-Orsay (France); Fromy, P. [CRI, UParis-Sud, 91405-Orsay (France); Gilles, D. [CEA/Saclay/DSM/IRFU/SAP, 91191-Gif-s-Yvette (France); Leger, D. [Laboratoire Monthouy, UValenciennes-Hainaut Cambresis (France); Maynard, G. [LPGP, UParis-Sud, 91405-Orsay (France); Tashev, B. [Department of Physics, KazNu, Tole Bi82, Almaty (Kazakhstan); Volpe, L. [Department of Physics, UMilano-Bicocca, Milano 20126 (Italy)

2014-01-01

Extensions of the standard stopping model (SSM) for ion projectiles interacting with dense targets of timely concern for ICF and WDM are reviewed. They include multiple scattering on partially degenerate electrons, low velocity ion slowing down in demixing H–He mixtures within Jovian planets core or multiionic target such as Kapton.

Multiple scattering in electron fluid and energy loss in multi-ionic targets

International Nuclear Information System (INIS)

Deutsch, C.; Tahir, N.A.; Barriga-Carrasco, M.; Ceban, V.; Fromy, P.; Gilles, D.; Leger, D.; Maynard, G.; Tashev, B.; Volpe, L.

2014-01-01

Extensions of the standard stopping model (SSM) for ion projectiles interacting with dense targets of timely concern for ICF and WDM are reviewed. They include multiple scattering on partially degenerate electrons, low velocity ion slowing down in demixing H–He mixtures within Jovian planets core or multiionic target such as Kapton

Double electron capture cross-sections of the ground state in the collisions of He2+ and Li3+ with He

International Nuclear Information System (INIS)

Purkait, M.

2004-01-01

We investigate the problem of the double charge transfer cross-section of a helium atom by bare ions of helium and lithium at energies ranging from 60 to 200 keV/amu. The boundary corrected continuum intermediate state approximation (BCCIS) is used to calculate the capture cross-section in the ground state. The continuum state of each electron has been accounted for in the formalism. The present results are compared with existing theoretical and experimental results. (authors)

Capture, Electron-Cooling and Compression of Antiprotons in a Large Penning-Trap for Physics Experiments with an Ultra-Low Energy Extracted Antiproton Beam

CERN Multimedia

2002-01-01

% PS200 \\\\ \\\\The availability of ultra-low energy antiprotons is a crucial ingredient for the execution of the gravity measurements PS200. We have developed a method to provide such low energy antiprotons based on a large Penning trap (the PS200 catching trap). This system can accept a fast-extracted pulse from LEAR, reduce the energy of the antiprotons in the pulse from 5.9~MeV to several tens of kilovolts using a degrading foil, and then capture the antiprotons in a large Penning trap. These antiprotons are cooled by electrons previously admitted to the trap and are collected in a small region at the center of the trap. We have demonstrated our capability to capture up to 1~million antiprotons from LEAR in a single shot, electron cool these antiprotons, and transfer up to 95\\% of them into the inner, harmonic region. A storage time in excess of 1 hour was observed. These results have been obtained with the cryogenic trap vacuum coupled to a room temperature vacuum at about l0$ ^- ^{1} ^0 $ Torr, which is an...

The capture rate of free-floating planets in our galaxy

Science.gov (United States)

Goulinski, N.; Ribak, E. N.

2017-09-01

We propose that planetary nebulae and supernova remnants may constitute a significant source of free-floating planets. With a large population of free-floating planets, the rate at which these planets get captured by planetary systems may be non-negligible. We predict that about one out of every 100 sub-solar stars are expected to experience a capture of a free-floating planet during their lifetime. The capture cross section calculated through three-body scattering simulations in vacuum conditions. Since planetary systems usually contain multiple planets, and dissipation processes where not included in the simulation, the capture rate may be higher.

Halogenated pesticide analysis in orange juice by gas chromatography with electron capture detector (GC-ECD) with "6"3Ni nuclide

International Nuclear Information System (INIS)

Manhani, Kelly C.; Amaral, Priscila O.; Bustillos, José O.V.; Mendes, Cristiana de A.; Lacerda, João P.A. de; Silva, Jorge L. da; Instituto de Pesquisas Tecnológicas do Estado de São Paulo

2017-01-01

Brazil has been gain space in the market of orange juice in the last years. For the exportation of this product to keep growing, its quality of this product must be ensured by putting in force more strict legislations and custom barriers, in order to improve the well-being and health of the population. In this work were analyzed four orange juices brands produced in the State of São Paulo. It was quantified the acaricide known as Dicofol (2,2,2-trichloro-1,1-bis(4-chlorophenyl) ethanol) widely used to combat the Citrusleprosis virus, transmitted by mites to the citrus culture. This pesticide was chosen due to its importance in the production of orange in large scale and their indiscriminate use may pose risks to humans and of environment. The analytical technique applied was gas chromatography coupled with electron capture detector (GC-ECD) using the "6"3Ni nuclide. This beta (β) radiation source ionizes the carrier gas (N_2), generating an electron current that forms the baseline. The analites pass through the detector and capture electrons, generating the analytical signal that is proportional to the concentration of analite. The sample preparation was done by QuEChERS. The limits of detection (LOD) and quantification (LOQ) found were 0.005 and 0.025 mg kg"-"1 respectively. The applied methodology was efficient and presented excellent analytical sensitivity for the pesticide Dicofol, being that of four samples analyzed, only in one was found concentration of 0.03 mg kg"-"1, above the LOQ, however below the Maximum Residue Limit (MRL) for fruits (0.1 mg kg"-"1) established by Codex alimentarius. (author)

Halogenated pesticide analysis in orange juice by gas chromatography with electron capture detector (GC-ECD) with {sup 63}Ni nuclide

Energy Technology Data Exchange (ETDEWEB)

Manhani, Kelly C.; Amaral, Priscila O.; Bustillos, José O.V.; Mendes, Cristiana de A.; Lacerda, João P.A. de; Silva, Jorge L. da, E-mail: ovega@ipen.br, E-mail: kmanhani@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (CQMA/IPEN-CNEN-SP), Sao Paulo, SP (Brazil). Centro de Química e Meio Ambiente; Instituto de Pesquisas Tecnológicas do Estado de São Paulo (LAQ- CQuim/IPT-SP), SP (Brazil). Lab. de Análises Químicas

2017-11-01

Brazil has been gain space in the market of orange juice in the last years. For the exportation of this product to keep growing, its quality of this product must be ensured by putting in force more strict legislations and custom barriers, in order to improve the well-being and health of the population. In this work were analyzed four orange juices brands produced in the State of São Paulo. It was quantified the acaricide known as Dicofol (2,2,2-trichloro-1,1-bis(4-chlorophenyl) ethanol) widely used to combat the Citrusleprosis virus, transmitted by mites to the citrus culture. This pesticide was chosen due to its importance in the production of orange in large scale and their indiscriminate use may pose risks to humans and of environment. The analytical technique applied was gas chromatography coupled with electron capture detector (GC-ECD) using the {sup 63}Ni nuclide. This beta (β) radiation source ionizes the carrier gas (N{sub 2}), generating an electron current that forms the baseline. The analites pass through the detector and capture electrons, generating the analytical signal that is proportional to the concentration of analite. The sample preparation was done by QuEChERS. The limits of detection (LOD) and quantification (LOQ) found were 0.005 and 0.025 mg kg{sup -1} respectively. The applied methodology was efficient and presented excellent analytical sensitivity for the pesticide Dicofol, being that of four samples analyzed, only in one was found concentration of 0.03 mg kg{sup -1}, above the LOQ, however below the Maximum Residue Limit (MRL) for fruits (0.1 mg kg{sup -1}) established by Codex alimentarius. (author)

Rapid differentiation of rocky mountain spotted fever from chickenpox, measles, and enterovirus infections and bacterial meningitis by frequency-pulsed electron capture gas-liquid chromatographic analysis of sera.

Science.gov (United States)

Brooks, J B; McDade, J E; Alley, C C

1981-01-01

Normal sera and sera from patients with Rocky Mountain spotted fever, chickenpox, enterovirus infections, measles, and Neisseria meningitidis infections were extracted with organic solvents under acidic and basic conditions and then derivatized with trichloroethanol or heptafluorobutyric anhydride-ethanol to form electron-capturing derivatives of organic acids, alcohols, and amines. The derivatives were analyzed by frequency-pulsed electron capture gas-liquid chromatography (FPEC-GLC). There were unique differences in the FPEC-GLC profiles of sera obtained from patients with these respective diseases. With Rocky Mountain spotted fever patients, typical profiles were detected as early as 1 day after onset of disease and before antibody could be detected in the serum. Rapid diagnosis of Rocky Mountain spotted fever by FPEC-GLC could permit early and effective therapy, thus preventing many deaths from this disease. PMID:7276147

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

Energy Technology Data Exchange (ETDEWEB)

NONE

1969-11-15

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

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

International Nuclear Information System (INIS)

1969-01-01

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

Theoretical analysis of moiré fringe multiplication under a scanning electron microscope

International Nuclear Information System (INIS)

Li, Yanjie; Xie, Huimin; Chen, Pengwan; Zhang, Qingming

2011-01-01

In this study, theoretical analysis and experimental verification of fringe multiplication under a scanning electron microscope (SEM) are presented. Fringe multiplication can be realized by enhancing the magnification or the number of scanning lines under the SEM. A universal expression of the pitch of moiré fringes is deduced. To apply this method to deformation measurement, the calculation formulas of strain and displacement are derived. Compared to natural moiré, the displacement sensitivity is increased by fringe multiplication while the strain sensitivity may be retained or enhanced depending on the number of scanning lines used. The moiré patterns are formed by the interference of a 2000 lines mm −1 grating with the scanning lines of SEM, and the measured parameters of moiré fringes from experimental results agree well with theoretical analysis

Dynamics in ion-molecule collisions at high velocities: One- and two-electron processes

International Nuclear Information System (INIS)

Wang, Yudong.

1992-01-01

This dissertation addresses the dynamic interactions in ion-molecule collisions. Theoretical methods are developed for single and multiple electron transitions in fast collisions with diatomic molecules by heavy-ion projectiles. Various theories and models are developed to treat the three basic inelastic processes (excitation, ionization and charge transfer) involving one and more electrons. The development, incorporating the understanding of ion-atom collision theories with some unique characteristics for molecular targets, provides new insights into phenomena that are absent from collisions with atomic targets. The influence from the multiple scattering centers on collision dynamics is assessed. For diatomic molecules, effects due to a fixed molecular orientation or alignment are calculated and compared with available experimental observations. Compared with excitation and ionization, electron capture, which probes deeper into the target, presents significant two-center interference and strong orientation dependence. Attention has been given in this dissertation to exploring mechanisms for two-and multiple electron transitions. Application of independent electron approximation to transfer excitation from molecular hydrogen is studied. Electron-electron interaction originated from projectile and target nuclear centers is studied in conjunction with the molecular nature of target. Limitations of the present theories and models as well as possible new areas for future theoretical and experimental applications are also discussed. This is the first attempt to describe multi-electron processes in molecular dynamics involving fast highly charged ions

Designing an Electronic Patient Management System for Multiple Sclerosis: Building a Next Generation Multiple Sclerosis Documentation System.

Science.gov (United States)

Kern, Raimar; Haase, Rocco; Eisele, Judith Christina; Thomas, Katja; Ziemssen, Tjalf

2016-01-08

Technologies like electronic health records or telemedicine devices support the rapid mediation of health information and clinical data independent of time and location between patients and their physicians as well as among health care professionals. Today, every part of the treatment process from diagnosis, treatment selection, and application to patient education and long-term care may be enhanced by a quality-assured implementation of health information technology (HIT) that also takes data security standards and concerns into account. In order to increase the level of effectively realized benefits of eHealth services, a user-driven needs assessment should ensure the inclusion of health care professional perspectives into the process of technology development as we did in the development process of the Multiple Sclerosis Documentation System 3D. After analyzing the use of information technology by patients suffering from multiple sclerosis, we focused on the needs of neurological health care professionals and their handling of health information technology. Therefore, we researched the status quo of eHealth adoption in neurological practices and clinics as well as health care professional opinions about potential benefits and requirements of eHealth services in the field of multiple sclerosis. We conducted a paper-and-pencil-based mail survey in 2013 by sending our questionnaire to 600 randomly chosen neurological practices in Germany. The questionnaire consisted of 24 items covering characteristics of participating neurological practices (4 items), the current use of network technology and the Internet in such neurological practices (5 items), physicians' attitudes toward the general and MS-related usefulness of eHealth systems (8 items) and toward the clinical documentation via electronic health records (4 items), and physicians' knowledge about the Multiple Sclerosis Documentation System (3 items). From 600 mailed surveys, 74 completed surveys were returned

Electron-photon and electron-electron interactions in the presence of strong electromagnetic fields

International Nuclear Information System (INIS)

Surzhykov, A.; Fritzsche, S.; Stoehlker, Th.

2010-01-01

During the last decade, photon emission from highly-charged, heavy ions has been in the focus of intense studies at the GSI accelerator and storage ring facility in Darmstadt. These studies have revealed unique information about the electron-electron and electron-photon interactions in the presence of extremely strong nuclear fields. Apart from the radiative electron capture processes, characteristic photon emission following collisional excitation of projectile ions has also attracted much interest. In this contribution, we summarize the recent theoretical studies on the production of excited ionic states and their subsequent radiative decay. We will pay special attention to the angular and polarization properties of Kα emission from helium-like ions produced by means of dielectronic recombination. The results obtained for this (resonant) capture process will be compared with the theoretical predictions for the characteristic X-rays following Coulomb excitation and radiative recombination of few-electron, heavy ions. Work is supported by Helmholtz Association and GSl under the project VH-NG--421. (author)

Detection efficiency for radionuclides decaying by electron capture and gamma-Ray; Calculo de la eficiencia de deteccion de nucleidos que se desintegran por captura elec- tronica y emision gamma

Energy Technology Data Exchange (ETDEWEB)

Grau, A; Fernandez, A

1985-07-01

In this paper, the electron capture partial counting efficiency vs the figure of merit for electron-capture and gamma-ray emitters has been computed. The radionuclides tabulated are 48{sup c}r, 54{sup M}n, 57{sup C}o 56{sup N}i, 72{sup S}e, 73{sup A}s, 85{sup S}r, 88{sup Z}r, 92{sup N}b, 103{sup P}d, 111{sup l}n, 119{sup S}b, 125{sup I}, 139{sup C}e and 152{sup D}y. It has been assumed that the liquid is a toluene based scintillator solution in standard glass vials containing 15 cm{sup 3}. (Author) 17 refs.

Shifting of the electron-capture-to-the-continuum peak in proton-helium collisions at 10 and 20 keV

International Nuclear Information System (INIS)

Bhattacharya, S.; Deb, N.C.; Roy, K.; Sahoo, S.; Crothers, D.S.F.

2005-01-01

A refined theoretical approach has been developed to study the double-differential cross sections (DDCS's) in proton-helium collisions as a function of the ratio of ionized electron velocity to the incident proton velocity. The refinement is done in the present coupled-channel calculation by introducing a continuum distorted wave in the final state coupled with discrete states including direct as well as charge transfer channels. It is confirmed that the electron-capture-to-the-continuum (ECC) peak is slightly shifted to a lower electron velocity than the equivelocity position. Comparing measurements and classical trajectory Monte Carlo (CTMC) calculations at 10 and 20 keV proton energies, excellent agreement of the ECC peak heights is achieved at both energies. However, a minor disagreement in the peak positions between the present calculation and the CTMC results is noted. A smooth behavior of the DDCS is found in the present calculation on both sides of the peak whereas the CTMC results show some oscillatory behavior particularly to the left of the peak, associated with the statistical nature of CTMC calculations

DeitY-TU face database: its design, multiple camera capturing, characteristics, and evaluation

Science.gov (United States)

Bhowmik, Mrinal Kanti; Saha, Kankan; Saha, Priya; Bhattacharjee, Debotosh

2014-10-01

The development of the latest face databases is providing researchers different and realistic problems that play an important role in the development of efficient algorithms for solving the difficulties during automatic recognition of human faces. This paper presents the creation of a new visual face database, named the Department of Electronics and Information Technology-Tripura University (DeitY-TU) face database. It contains face images of 524 persons belonging to different nontribes and Mongolian tribes of north-east India, with their anthropometric measurements for identification. Database images are captured within a room with controlled variations in illumination, expression, and pose along with variability in age, gender, accessories, make-up, and partial occlusion. Each image contains the combined primary challenges of face recognition, i.e., illumination, expression, and pose. This database also represents some new features: soft biometric traits such as mole, freckle, scar, etc., and facial anthropometric variations that may be helpful for researchers for biometric recognition. It also gives an equivalent study of the existing two-dimensional face image databases. The database has been tested using two baseline algorithms: linear discriminant analysis and principal component analysis, which may be used by other researchers as the control algorithm performance score.

Inelastic electron scattering and radiative pion capture to the lowest 1+ and 2+ isovector levels in A=12 nuclei. Continuity-equation effects

International Nuclear Information System (INIS)

Eramzhyan, R.A.; Gmitro, M.; Kaipov, T.D.; Kamalov, S.S.; Mach, R.

1983-01-01

Continuity equation for the nuclear electric charge and convection current has been used in an analysis of nuclear transition densities in 12 C. The results differ considerably from the former derivations. Standard M1 and calculated E2 nuclear transition densities are fixed which provide an accurate description of the electron scattering data. Such a nuclear structure imput is used in the radiative pion capture calculations

Probabilities and energies to obtain the counting efficiency of electron-capture nuclides. KLMN model; Probabilidades y energias de reestructuracion atomica subsiguientes a la captura electronica. Modelo KLMN

Energy Technology Data Exchange (ETDEWEB)

Galiano, G.; Grau, A.

1994-07-01

An intelligent computer program has been developed to obtain the mathematical formulae to compute the probabilities and reduced energies of the different atomic rearrangement pathways following electron-capture decay. Creation and annihilation operators for Auger and X processes have been introduced. Taking into account the symmetries associated with each process, 262 different pathways were obtained. This model allows us to obtain the influence of the M-electro capture in the counting efficiency when the atomic number of the nuclide is high. (Author)

Determination of Psub(K) values to the 172, 103 and 97 keV levels and the fluorescence yield. omega. sub(K) of Eu after electron capture by /sup 153/Gd

Energy Technology Data Exchange (ETDEWEB)

Singh, K; Grewal, B S; Sahota, H S [Punjabi Univ., Patiala (India). Dept. of Physics

1985-03-01

From an analysis of K x-ray-..gamma..-ray sum peaks observed with an intrinsic Ge detector the K-capture probabilities (Psub(K)) to the 172, 103 and 97 keV levels in the decay of /sup 153/Gd have been determined; these yield an electron-capture energy Qsub(EC)=245 +- 2. The K-capture probability to the 172 keV level differs significantly from that found in the literature. With these results the K-shell fluorescence yield of Eu is ..omega..sub(K)=0.935 +- 0.019.

Analysis of multiple scattering contributions in electron-impact ionization of molecular hydrogen

Science.gov (United States)

Ren, Xueguang; Hossen, Khokon; Wang, Enliang; Pindzola, M. S.; Dorn, Alexander; Colgan, James

2017-10-01

We report a combined experimental and theoretical study on the low-energy (E 0 = 31.5 eV) electron-impact ionization of molecular hydrogen (H2). Triple differential cross sections are measured for a range of fixed emission angles of one outgoing electron between {θ }1=-70^\\circ and -130° covering the full 4π solid angle of the second electron. The energy sharing of the outgoing electrons varies from symmetric ({E}1={E}2=8 eV) to highly asymmetric (E 1 = 1 eV and E 2 = 15 eV). In addition to the binary and recoil lobes, a structure is observed perpendicular to the incoming beam direction which is due to multiple scattering of the projectile inside the molecular potential. The absolutely normalized experimental cross sections are compared with results from the time-dependent close-coupling (TDCC) calculations. Molecular alignment dependent TDCC results demonstrate that these structures are only present if the molecule axis is lying in the scattering plane.

A multiple gap plasma cathode electron gun and its electron beam analysis in self and trigger breakdown modes

International Nuclear Information System (INIS)

Kumar, Niraj; Pal, Udit Narayan; Prakash, Ram; Pal, Dharmendra Kumar; Jadon, Arvind Singh; Rahaman, Hasibur

2016-01-01

In the present paper, a pseudospark discharge based multiple gap plasma cathode electron gun is reported which has been operated separately in self and trigger breakdown modes using two different gases, namely, argon and hydrogen. The beam current and beam energy have been analyzed using a concentric ring diagnostic arrangement. Two distinct electron beams are clearly seen with hollow cathode and conductive phases. The hollow cathode phase has been observed for ∼50 ns where the obtained electron beam is having low beam current density and high energy. While in conductive phase it is high current density and low energy electron beam. It is inferred that in the hollow cathode phase the beam energy is more for the self breakdown case whereas the current density is more for the trigger breakdown case. The tailor made operation of the hollow cathode phase electron beam can play an important role in microwave generation. Up to 30% variation in the electron beam energy has been achieved keeping the same gas and by varying the breakdown mode operations. Also, up to 32% variation in the beam current density has been achieved for the trigger breakdown mode at optimized trigger position by varying the gas type.

A multiple gap plasma cathode electron gun and its electron beam analysis in self and trigger breakdown modes.

Science.gov (United States)

Kumar, Niraj; Pal, Dharmendra Kumar; Jadon, Arvind Singh; Pal, Udit Narayan; Rahaman, Hasibur; Prakash, Ram

2016-03-01

In the present paper, a pseudospark discharge based multiple gap plasma cathode electron gun is reported which has been operated separately in self and trigger breakdown modes using two different gases, namely, argon and hydrogen. The beam current and beam energy have been analyzed using a concentric ring diagnostic arrangement. Two distinct electron beams are clearly seen with hollow cathode and conductive phases. The hollow cathode phase has been observed for ∼50 ns where the obtained electron beam is having low beam current density and high energy. While in conductive phase it is high current density and low energy electron beam. It is inferred that in the hollow cathode phase the beam energy is more for the self breakdown case whereas the current density is more for the trigger breakdown case. The tailor made operation of the hollow cathode phase electron beam can play an important role in microwave generation. Up to 30% variation in the electron beam energy has been achieved keeping the same gas and by varying the breakdown mode operations. Also, up to 32% variation in the beam current density has been achieved for the trigger breakdown mode at optimized trigger position by varying the gas type.

A multiple gap plasma cathode electron gun and its electron beam analysis in self and trigger breakdown modes

Energy Technology Data Exchange (ETDEWEB)

Kumar, Niraj; Pal, Udit Narayan; Prakash, Ram [CSIR-Central Electronics Engineering Research Institute (CSIR-CEERI), Pilani, Rajasthan 333031 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR-CEERI Campus, Pilani (India); Pal, Dharmendra Kumar; Jadon, Arvind Singh; Rahaman, Hasibur [CSIR-Central Electronics Engineering Research Institute (CSIR-CEERI), Pilani, Rajasthan 333031 (India)

2016-03-15

In the present paper, a pseudospark discharge based multiple gap plasma cathode electron gun is reported which has been operated separately in self and trigger breakdown modes using two different gases, namely, argon and hydrogen. The beam current and beam energy have been analyzed using a concentric ring diagnostic arrangement. Two distinct electron beams are clearly seen with hollow cathode and conductive phases. The hollow cathode phase has been observed for ∼50 ns where the obtained electron beam is having low beam current density and high energy. While in conductive phase it is high current density and low energy electron beam. It is inferred that in the hollow cathode phase the beam energy is more for the self breakdown case whereas the current density is more for the trigger breakdown case. The tailor made operation of the hollow cathode phase electron beam can play an important role in microwave generation. Up to 30% variation in the electron beam energy has been achieved keeping the same gas and by varying the breakdown mode operations. Also, up to 32% variation in the beam current density has been achieved for the trigger breakdown mode at optimized trigger position by varying the gas type.

Electrofishing capture probability of smallmouth bass in streams

Science.gov (United States)

Dauwalter, D.C.; Fisher, W.L.

2007-01-01

Abundance estimation is an integral part of understanding the ecology and advancing the management of fish populations and communities. Mark-recapture and removal methods are commonly used to estimate the abundance of stream fishes. Alternatively, abundance can be estimated by dividing the number of individuals sampled by the probability of capture. We conducted a mark-recapture study and used multiple repeated-measures logistic regression to determine the influence of fish size, sampling procedures, and stream habitat variables on the cumulative capture probability for smallmouth bass Micropterus dolomieu in two eastern Oklahoma streams. The predicted capture probability was used to adjust the number of individuals sampled to obtain abundance estimates. The observed capture probabilities were higher for larger fish and decreased with successive electrofishing passes for larger fish only. Model selection suggested that the number of electrofishing passes, fish length, and mean thalweg depth affected capture probabilities the most; there was little evidence for any effect of electrofishing power density and woody debris density on capture probability. Leave-one-out cross validation showed that the cumulative capture probability model predicts smallmouth abundance accurately. ?? Copyright by the American Fisheries Society 2007.

ELECTRON-CAPTURE IN HIGHLY-CHARGED ION-ATOM COLLISIONS

NARCIS (Netherlands)

MORGENSTERN, R

1993-01-01

An attempt is made to identify the most important mechanisms responsible for the rearrangement of electrons during collisions between multiply charged ions and atoms at keV energies. It is discussed to which extent the influence of binding energy, angular momentum of heavy particles and electrons,

Dose rate effect on micronuclei induction in human blood lymphocytes exposed to single pulse and multiple pulses of electrons.

Science.gov (United States)

Acharya, Santhosh; Bhat, N N; Joseph, Praveen; Sanjeev, Ganesh; Sreedevi, B; Narayana, Y

2011-05-01

The effects of single pulses and multiple pulses of 7 MV electrons on micronuclei (MN) induction in cytokinesis-blocked human peripheral blood lymphocytes (PBLs) were investigated over a wide range of dose rates per pulse (instantaneous dose rate). PBLs were exposed to graded doses of 2, 3, 4, 6, and 8 Gy of single electron pulses of varying pulse widths at different dose rates per pulse, ranging from 1 × 10(6) Gy s(-1) to 3.2 × 10(8) Gy s(-1). Different dose rates per pulse were achieved by changing the dose per electron pulse by adjusting the beam current and pulse width. MN yields per unit absorbed dose after irradiation with single electron pulses were compared with those of multiple pulses of electrons. A significant decrease in the MN yield with increasing dose rates per pulse was observed, when dose was delivered by a single electron pulse. However, no reduction in the MN yield was observed when dose was delivered by multiple pulses of electrons. The decrease in the yield at high dose rates per pulse suggests possible radical recombination, which leads to decreased biological damage. Cellular response to the presence of very large numbers of chromosomal breaks may also alter the damage.

A New Mass Criterium for Electron Capture Supernovae

Science.gov (United States)

Poelarends, Arend

2016-06-01

Electron capture supernovae (ECSN) are thought to populate the mass range between massive white dwarf progenitors and core collapse supernovae. It is generally believed that the initial stellar mass range for ECSN from single stars is about 0.5-1.0 M⊙ wide and centered around a value of 8.5 or 9 M⊙, depending on the specifics of the physics of convection and mass loss one applies. Since mass loss in a binary system is able to delay or cancel the second dredge-up, it is also believed that the initial mass range for ECSN in binary systems is wider than in single stars, but an initial mass range has not been defined yet.The last phase of stars in this particular mass range, however, is challenging to compute, either due to recurring Helium shell flashes, or due to convectively bound flames in the degenerate interior of the star. It would be helpful, nevertheless, to know before we enter these computationally intensive phases whether a star will explode as an ECSN or not. The mass of the helium core after helium core burning is one such criterium (Nomoto, 1984), which predicts that ECSN will occur if the helium core mass is between 2.0 M⊙ and 2.5 M⊙. However, since helium cores can be subject to erosion due to mass loss — even during helium core burning, this criterium will not yield accurate predictions for stars in binary systems.We present a dense grid of stellar evolution models that allow us to put constraints on the final fate of their cores, based on a combination of Carbon/Oxygen core mass, the mass of the surrounding Helium layer and C/O abundance. We find that CO cores with masses between 1.365 and 1.420 M⊙ at the end of Carbon burning will result in ECSN, with some minor adjustments of these ranges due to the mass of the Helium layer and the C/O ratio. While detailed models of stars within the ECSN mass range remain necessary to understand the details of pre-ECSN evolution, our research refines the Helium core criterion and provides a useful way

New measurement of neutron capture resonances of 209Bi

CERN Document Server

Domingo-Pardo, C.; Aerts, G.; Alvarez-Pol, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvar, F.; Berthoumieux, E.; Calvino, F.; Cano-Ott, D.; Capote, R.; Carrillode Albornoz, A.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillman, I.; Dolfini, R.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fitzpatrick, L.; Frais-Koelbl, H.; Fujii, K.; Furman, W.; Gallino, R.; Goncalves, I.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Isaev, S.; Jericha, E.; Kadi, Y.; Kappeler, F.; Karamanis, D.; Karadimos, D.; Kerveno, M.; Ketlerov, V.; Koehler, P.; Konovalov, V.; Kossionides, E.; Krticka, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marques, L.; Marrone, S.; Mastinu, P.; Mengoni, A.; Milazzo, P.M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; Oshima, M.; O'Brien, S.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tagliente, G.; Tain, J.L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, Alberto; Villamarin, D.; Vincente, M.C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wendler, H.; Wiescher, M.; Wisshak, K.

2006-01-01

The neutron capture cross section of Bi209 has been measured at the CERN n TOF facility by employing the pulse-height-weighting technique. Improvements over previous measurements are mainly because of an optimized detection system, which led to a practically negligible neutron sensitivity. Additional experimental sources of systematic error, such as the electronic threshold in the detectors, summing of gamma-rays, internal electron conversion, and the isomeric state in bismuth, have been taken into account. Gamma-ray absorption effects inside the sample have been corrected by employing a nonpolynomial weighting function. Because Bi209 is the last stable isotope in the reaction path of the stellar s-process, the Maxwellian averaged capture cross section is important for the recycling of the reaction flow by alpha-decays. In the relevant stellar range of thermal energies between kT=5 and 8 keV our new capture rate is about 16% higher than the presently accepted value used for nucleosynthesis calculations. At th...

Cross sections for one-electron capture by highly stripped ions of Be, B and C from H2 and Ar below 10 keV

International Nuclear Information System (INIS)

Takagi, S.; Ohtani, S.; Kadota, K.; Fujita, J.

1982-03-01

Cross sections for one-electron capture by highly stripped ions of Be, B and C from H 2 and Ar are measured at low energies below 10 keV. The cross sections are nearly independent of the collision energy investigated. The distinct oscillation with incident ionic charge g in the cross sections are observed. (author)

Coherent Electron Scattering Captured by an Attosecond Quantum Stroboscope

International Nuclear Information System (INIS)

Mauritsson, J.; Johnsson, P.; Mansten, E.; Swoboda, M.; Ruchon, T.; L'Huillier, A.; Schafer, K. J.

2008-01-01

We demonstrate a quantum stroboscope based on a sequence of identical attosecond pulses that are used to release electrons into a strong infrared (IR) laser field exactly once per laser cycle. The resulting electron momentum distributions are recorded as a function of time delay between the IR laser and the attosecond pulse train using a velocity map imaging spectrometer. Because our train of attosecond pulses creates a train of identical electron wave packets, a single ionization event can be studied stroboscopically. This technique has enabled us to image the coherent electron scattering that takes place when the IR field is sufficiently strong to reverse the initial direction of the electron motion causing it to rescatter from its parent ion

Formation Process of Non-Neutral Plasmas by Multiple Electron Beams on BX-U

Science.gov (United States)

Sanpei, Akio; Himura, Haruhiko; Masamune, Sadao

An imaging diagnostic system, which is composed of a handmade phosphor screen and a high-speed camera, has been applied to identify the dynamics of multiple electron beams on BX-U. The relaxation process of those toward a non-neutral plasma is experimentally identified. Also, the radial density profile of the plasma is measured as a function of time. Assuming that the plasma is a spheroidal shape, the value of electron density ne is in the range between 2.2 × 106 and 4.4 × 108 cm-3 on BX-U.

Capturing the experiences of patients across multiple complex interventions: a meta-qualitative approach.

Science.gov (United States)

Webster, Fiona; Christian, Jennifer; Mansfield, Elizabeth; Bhattacharyya, Onil; Hawker, Gillian; Levinson, Wendy; Naglie, Gary; Pham, Thuy-Nga; Rose, Louise; Schull, Michael; Sinha, Samir; Stergiopoulos, Vicky; Upshur, Ross; Wilson, Lynn

2015-09-08

The perspectives, needs and preferences of individuals with complex health and social needs can be overlooked in the design of healthcare interventions. This study was designed to provide new insights on patient perspectives drawing from the qualitative evaluation of 5 complex healthcare interventions. Patients and their caregivers were recruited from 5 interventions based in primary, hospital and community care in Ontario, Canada. We included 62 interviews from 44 patients and 18 non-clinical caregivers. Our team analysed the transcripts from 5 distinct projects. This approach to qualitative meta-evaluation identifies common issues described by a diverse group of patients, therefore providing potential insights into systems issues. This study is a secondary analysis of qualitative data; therefore, no outcome measures were identified. We identified 5 broad themes that capture the patients' experience and highlight issues that might not be adequately addressed in complex interventions. In our study, we found that: (1) the emergency department is the unavoidable point of care; (2) patients and caregivers are part of complex and variable family systems; (3) non-medical issues mediate patients' experiences of health and healthcare delivery; (4) the unanticipated consequences of complex healthcare interventions are often the most valuable; and (5) patient experiences are shaped by the healthcare discourses on medically complex patients. Our findings suggest that key assumptions about patients that inform intervention design need to be made explicit in order to build capacity to better understand and support patients with multiple chronic diseases. Across many health systems internationally, multiple models are being implemented simultaneously that may have shared features and target similar patients, and a qualitative meta-evaluation approach, thus offers an opportunity for cumulative learning at a system level in addition to informing intervention design and

Using Electronic Health Record Data to Measure Care Quality for Individuals with Multiple Chronic Medical Conditions.

Science.gov (United States)

Bayliss, Elizabeth A; McQuillan, Deanna B; Ellis, Jennifer L; Maciejewski, Matthew L; Zeng, Chan; Barton, Mary B; Boyd, Cynthia M; Fortin, Martin; Ling, Shari M; Tai-Seale, Ming; Ralston, James D; Ritchie, Christine S; Zulman, Donna M

2016-09-01

To inform the development of a data-driven measure of quality care for individuals with multiple chronic conditions (MCCs) derived from an electronic health record (EHR). Qualitative study using focus groups, interactive webinars, and a modified Delphi process. Research department within an integrated delivery system. The webinars and Delphi process included 17 experts in clinical geriatrics and primary care, health policy, quality assessment, health technology, and health system operations. The focus group included 10 individuals aged 70-87 with three to six chronic conditions selected from a random sample of individuals aged 65 and older with three or more chronic medical conditions. Through webinars and the focus group, input was solicited on constructs representing high-quality care for individuals with MCCs. A working list was created of potential measures representing these constructs. Using a modified Delphi process, experts rated the importance of each possible measure and the feasibility of implementing each measure using EHR data. High-priority constructs reflected processes rather than outcomes of care. High-priority constructs that were potentially feasible to measure included assessing physical function, depression screening, medication reconciliation, annual influenza vaccination, outreach after hospital admission, and documented advance directives. High-priority constructs that were less feasible to measure included goal setting and shared decision-making, identifying drug-drug interactions, assessing social support, timely communication with patients, and other aspects of good customer service. Lower-priority domains included pain assessment, continuity of care, and overuse of screening or laboratory testing. High-quality MCC care should be measured using meaningful process measures rather than outcomes. Although some care processes are currently extractable from electronic data, capturing others will require adapting and applying technology to

Investigation by high resolution electron spectroscopy of the helium-like 3lnl' Rydberg series in double capture processes at low collision velocity: auto transfer to Rydberg states and electron stabilization

International Nuclear Information System (INIS)

Bordenave-Montesquieu, A.; Moretto-Capelle, P.; Gonzalez, A.; Benhenni, M.; Bachau, H.; Sanchez, I.

1994-01-01

A high resolution electron spectrometry of the (3lnl') Ryberg series populated in N 7+ + He and Ne 10+ + He collisions at 10 q keV, 10 o allows us to observe, for the first time by this method, two post-collisional effects. First, it is found with nitrogen ions that, when n increases from n = 4 to 9, the L-distribution peaks more and more on the high angular momentum states. This is qualitatively understood as a Stark deformation of the Rydberg orbit by the Coulomb field of the receding ion. Also, in the n range where the double capture process populates symmetrical 4l4l' states (n>9), an enhancement of the intensities of the 3lnl' Rydberg lines is observed for both collisonal systems. This is thought to be a signature of the so-called auto transfer to Rydberg states effect. The transfer of population from the 3l4l' to the 3lnl' states is found to be favoured against a direct autoionization of these 4l4l' states into the n = 2 continuum. These experimental findings together with preliminary spectroscopic calculations concerning the configuration interaction of the Ne 8+ (4l4l') states with the Ne 8+ (3lnl') Rydberg series are also discussed within the context of the electron stabilization which follows a double capture. (Author)

Embracing Electronic Publishing.

Science.gov (United States)

Wills, Gordon

1996-01-01

Electronic publishing is the grandest revolution in the capture and dissemination of academic and professional knowledge since Caxton developed the printing press. This article examines electronic publishing, describes different electronic publishing scenarios (authors' cooperative, consolidator/retailer/agent oligopsony, publisher oligopoly), and…

The use of multiple imputation for the accurate measurements of individual feed intake by electronic feeders.

Science.gov (United States)

Jiao, S; Tiezzi, F; Huang, Y; Gray, K A; Maltecca, C

2016-02-01

Obtaining accurate individual feed intake records is the key first step in achieving genetic progress toward more efficient nutrient utilization in pigs. Feed intake records collected by electronic feeding systems contain errors (erroneous and abnormal values exceeding certain cutoff criteria), which are due to feeder malfunction or animal-feeder interaction. In this study, we examined the use of a novel data-editing strategy involving multiple imputation to minimize the impact of errors and missing values on the quality of feed intake data collected by an electronic feeding system. Accuracy of feed intake data adjustment obtained from the conventional linear mixed model (LMM) approach was compared with 2 alternative implementations of multiple imputation by chained equation, denoted as MI (multiple imputation) and MICE (multiple imputation by chained equation). The 3 methods were compared under 3 scenarios, where 5, 10, and 20% feed intake error rates were simulated. Each of the scenarios was replicated 5 times. Accuracy of the alternative error adjustment was measured as the correlation between the true daily feed intake (DFI; daily feed intake in the testing period) or true ADFI (the mean DFI across testing period) and the adjusted DFI or adjusted ADFI. In the editing process, error cutoff criteria are used to define if a feed intake visit contains errors. To investigate the possibility that the error cutoff criteria may affect any of the 3 methods, the simulation was repeated with 2 alternative error cutoff values. Multiple imputation methods outperformed the LMM approach in all scenarios with mean accuracies of 96.7, 93.5, and 90.2% obtained with MI and 96.8, 94.4, and 90.1% obtained with MICE compared with 91.0, 82.6, and 68.7% using LMM for DFI. Similar results were obtained for ADFI. Furthermore, multiple imputation methods consistently performed better than LMM regardless of the cutoff criteria applied to define errors. In conclusion, multiple imputation

Neuroinformatics Software Applications Supporting Electronic Data Capture, Management, and Sharing for the Neuroimaging Community.

Science.gov (United States)

Nichols, B Nolan; Pohl, Kilian M

2015-09-01

Accelerating insight into the relation between brain and behavior entails conducting small and large-scale research endeavors that lead to reproducible results. Consensus is emerging between funding agencies, publishers, and the research community that data sharing is a fundamental requirement to ensure all such endeavors foster data reuse and fuel reproducible discoveries. Funding agency and publisher mandates to share data are bolstered by a growing number of data sharing efforts that demonstrate how information technologies can enable meaningful data reuse. Neuroinformatics evaluates scientific needs and develops solutions to facilitate the use of data across the cognitive and neurosciences. For example, electronic data capture and management tools designed to facilitate human neurocognitive research can decrease the setup time of studies, improve quality control, and streamline the process of harmonizing, curating, and sharing data across data repositories. In this article we outline the advantages and disadvantages of adopting software applications that support these features by reviewing the tools available and then presenting two contrasting neuroimaging study scenarios in the context of conducting a cross-sectional and a multisite longitudinal study.

Gas chromatographic determination with electron capture detection of residual ethylene oxide in intraocular lenses

Energy Technology Data Exchange (ETDEWEB)

Kikuchi, H.; Nakamura, A.; Tsuji, K.

1988-01-01

A sensitive method is described to determine trace quantities of ethylene oxide (EO) in EO-sterilized intraocular lenses (IOLs). An IOL is dipped in ethanol containing 0.25 ppm propylene oxide (PO) in a 4 mL vial, 2 drops of freshly distilled hydrobromic acid is added through a septum, and the mixture is warmed at 50/sup 0/C for 24 h. It is then neutralized by vigorous shaking with sodium bicarbonate, dehydrated with anhydrous sodium sulfate, and filtered. The filtrate is injected into a gas chromatograph with electron-capture detection, and the peak height ratio of ethylene bromohydrin/propylene bromohydrin is measured. EO residue is calculated from the calibration curve obtained through a similar procedure with the standard EO/PO solutions. The limit of determination is 0.04 ..mu..g/lens (ca 2.0 ppm). When EO residue levels were determined for IOLs sampled at 3 different aeration periods after stabilization, the authors found that 9 days of aeration was necessary to meet the US Food and Drug Administration proposed limit for EO residue in IOLs.

Towards a Room-Temperature Spin Quantum Bus in Diamond via Electron Photoionization, Transport, and Capture

Directory of Open Access Journals (Sweden)

M. W. Doherty

2016-11-01

Full Text Available Diamond is a proven solid-state platform for spin-based quantum technology. The nitrogen-vacancy center in diamond has been used to realize small-scale quantum information processing and quantum sensing under ambient conditions. A major barrier in the development of large-scale quantum information processing in diamond is the connection of nitrogen-vacancy spin registers by a quantum bus at room temperature. Given that diamond is expected to be an ideal spin transport material, the coherent transport of spin directly between the spin registers offers a potential solution. Yet, there has been no demonstration of spin transport in diamond due to difficulties in achieving spin injection and detection via conventional methods. Here, we exploit detailed knowledge of the paramagnetic defects in diamond to identify novel mechanisms to photoionize, transport, and capture spin-polarized electrons in diamond at room temperature. Having identified these mechanisms, we explore how they may be combined to realize an on-chip spin quantum bus.

Electron-capture cross sections for low-energy highly charged neon and argon ions from molecular and atomic hydrogen

International Nuclear Information System (INIS)

Can, C.; Gray, T.J.; Varghese, S.L.; Hall, J.M.; Tunnell, L.N.

1985-01-01

Electron-capture cross sections for low-velocity (10 6 --10 7 cm/s) highly charged Ne/sup q/+ (2< or =q< or =7) and Ar/sup q/+ (2< or =q< or =10)= projectiles incident on molecular- and atomic-hydrogen targets have been measured. A recoil-ion source that used the collisions of fast heavy ions (1 MeV/amu) with target gas atoms was utilized to produce slow highly charged ions. Atomic hydrogen was produced by dissociating hydrogen molecules in a high-temperature oven. Measurements and analysis of the data for molecular- and atomic-hydrogen targets are discussed in detail. The measured absolute cross sections are compared with published data and predictions of theoretical models

Single electron ionization and electron capture cross sections for (C{sup 6+}, H{sub 2}O) interaction within the Classical Trajectory Monte Carlo (CTMC) approach

Energy Technology Data Exchange (ETDEWEB)

Tran, H.N., E-mail: tranngochoang@tdt.edu.vn [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Dao, D.D. [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Incerti, S. [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Université de Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); Bernal, M.A. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, SP (Brazil); Karamitros, M. [CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Université de Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); Nhan Hao, T.V. [Center of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam); Center for Theoretical and Computational Physics, College of Education, Hue University, 34 Le Loi Street, Hue City (Viet Nam); Dang, T.M. [VNUHCM-University of Science (Viet Nam); Francis, Z. [Saint Joseph University, Beyrouth (Lebanon)

2016-01-01

In this work, we present a derivation of cross sections for single ionization and electron capture processes within the Classical Trajectory Monte Carlo (CTMC) approach. Specifically, we have used a potential stemming from an ab initio calculation in Green et al.’s framework to describe the dynamics of the water molecule system. Proposing a modified version of the Classical Over-Barrier (COB) potential, we have found that a cut-off of roughly 28 a.u. on the initial distance of the projectile produced a reasonable accuracy. A global agreement has been obtained in our calculations compared to experimental and other theoretical results for C{sup 6+} ion energies ranging from 10 keV/u to 10 MeV/u.

The Prevalence of Multiple Sclerosis in the Metropolitan Area of Rome: A Capture-Recapture Analysis.

Science.gov (United States)

Farcomeni, Alessio; Cortese, Antonio; Sgarlata, Eleonora; Alunni Fegatelli, Danilo; Marfia, Gerolama Alessandra; Buttari, Fabio; Mirabella, Massimiliano; De Fino, Chiara; Prosperini, Luca; Pozzilli, Carlo; Grasso, Maria Grazia; Iasevoli, Luigi; Di Battista, Giancarlo; Millefiorini, Enrico

2018-03-02

Limited data are available on the prevalence of multiple sclerosis (MS) in central Italy. The objective of this study is to estimate MS prevalence in the metropolitan area of Rome. We used the capture-recapture method to calculate prevalence estimates in the study area. The selected prevalence day was December 31, 2015. A total of 1,007 patients, with a definite diagnosis of MS according to the revised McDonald's criteria, were considered for crude, age- and sex-specific prevalence estimation. The overall crude prevalence rate was 146.2 cases per 100,000 (95% CI 119.9-172.5). A higher prevalence rate was recorded in females (194.1, 95% CI 149.6-238.6) than in males (93.0, 95% CI 67.2-118.8) with a female to male ratio of 1.8. Age-specific prevalence peaked in the 25-34 , 35-44 and 45-54 years class; moreover, it was found to increase up to the 45-54 years age group in females and the 35-44 years age group in males, decreasing thereafter. The results confirm that the metropolitan area of Rome is a high-risk area for MS. © 2018 S. Karger AG, Basel.

Managing terminology assets in Electronic Health Records.

Science.gov (United States)

Abrams, Kelly; Schneider, Sue; Scichilone, Rita

2009-01-01

Electronic Health Record (EHR)systems rely on standard terminologies and classification systems that require both Information Technology (IT) and Information Management (IM) skills. Convergence of perspectives is necessary for effective terminology asset management including evaluation for use, maintenance and intersection with software applications. Multiple terminologies are necessary for patient care communication and data capture within EHRs and other information management tasks. Terminology asset management encompasses workflow and operational context as well as IT specifications and software application run time requirements. This paper identifies the tasks, skills and collaboration of IM and IT approaches for terminology asset management.

A data-capture system for post-marketing surveillance of drugs that integrates with hospital electronic health records

Directory of Open Access Journals (Sweden)

Yamamoto K

2011-04-01

Full Text Available Keiichi Yamamoto1, Shigemi Matsumoto2, Kazuhiro Yanagihara2, Satoshi Teramukai1, Masanori Fukushima1,2,31Department of Clinical Trial Design and Management, Translational Research Center, Kyoto University Hospital, Kyoto, Japan; 2Outpatient Oncology Unit, Kyoto University Hospital, Kyoto, Japan; 3Translational Research Informatics Center, Foundation for Biomedical Research and Innovation, Kobe, JapanPurpose: In conventional clinical studies, the cost of data management for the purposes of quality control tend to be high and collecting paper-based case report forms (CRFs can be burdensome, because paper-based CRFs must be developed and filled out for each clinical study protocol. Use of electronic health records (EHRs for this purpose could reduce costs and improve data quality in clinical studies. Kyoto University Hospital launched an EHR system in January 2005. At the same time, a replicate of that database was established for other purposes. At the Outpatient Oncology Unit of Kyoto University Hospital we developed a data-capture system that includes a cancer clinical database system and a data warehouse for outcomes studies. This system allows us to accumulate data at low cost and apply it to various uses in clinical or outcomes studies. Here we report on the application of this system to the post-marketing surveillance of drugs.Methods: We evaluated the availability of this system and identified problems for future development. With this system investigators can register cases for post-marketing surveillance, and the registered cases are listed on a screen. When CRFs for a particular case are required, data can be extracted from the list and CRFs are produced in PDF format.Results and conclusion: In this study we confirmed the applicability of our new system to post-marketing surveillance in providing prompt and efficient data exchange. We expect it to reduce the cost of data management and analysis and to improve the quality of data in post

Influence of the parameters of supplying pulses and polarization voltage on the signal and shape of current characteristics of the electron capture detector

International Nuclear Information System (INIS)

Lasa, J.; Sliwka, I.; Drozdowicz, B.

1989-01-01

The paper contains results of measurements of current characteristics and of the signal for the constant concentration of freon F-11 of the ECD supplied with pulse voltage of changeable time of pulse duration t p , amplitude U 1 and the time of pulse repetition t r . In the course of measurements the detector worked at temperature 573 K with the additional constant polarization voltage. The polarization voltage has been observed to cause the effect of hypercoulometry. The presented mathematical analysis helps to determine the values of the coefficient of efficiency of electron capture p, the coefficient of electron loss k D , the coefficient of collecting of electric charges by the anode k' 3 and the coefficient of collecting of electric charges by the detector cathode k u . The coefficients are determined on the basis of experimental measurements. An attempt of physical interpretation of calculated values of these coefficients and their dependence on the parameters of the pulses supplying the detector has been presented. This interpretation requires the assumption that in some pulse periods t r the concentration of positive ions in the detector considerably exceeds concentration n 0 + = √a xα e /V, where a is an efficiency of the carrier gas ionization, α e is the coefficient of the electron-ion recombination and V is the detector volume. This statement helping to describe the effects observed in the electron capture polarized by voltage U a contradicts the recognized concept that the concentration of positive ions in the detector does not exceed the concentration n 0 + . The paper shows that the detector of the cylindrical construction, supplied with a pulse voltage can be used for coulometric measurements and the voltage polarizing the cathode can cause an effect of hypercoulometry. 33 figs., 9 refs. (author)

Few-Photon Multiple Ionization of Ne and Ar by Strong Free-Electron-Laser Pulses

International Nuclear Information System (INIS)

Moshammer, R.; Jiang, Y. H.; Rudenko, A.; Ergler, Th.; Schroeter, C. D.; Luedemann, S.; Zrost, K.; Dorn, A.; Ferger, T.; Kuehnel, K. U.; Ullrich, J.; Foucar, L.; Titze, J.; Jahnke, T.; Schoeffler, M.; Doerner, R.; Fischer, D.; Weber, T.; Zouros, T. J. M.; Duesterer, S.

2007-01-01

Few-photon multiple ionization of Ne and Ar atoms by strong vacuum ultraviolet laser pulses from the free-electron laser at Hamburg was investigated differentially with the Heidelberg reaction microscope. The light-intensity dependence of Ne 2+ production reveals the dominance of nonsequential two-photon double ionization at intensities of I 12 W/cm 2 and significant contributions of three-photon ionization as I increases. Ne 2+ recoil-ion-momentum distributions suggest that two electrons absorbing ''instantaneously'' two photons are ejected most likely into opposite hemispheres with similar energies

A binomial and species-independent approach to trap capture analysis of flying insects

Science.gov (United States)

Interpretation of trap captures of flying insects is hampered by factors associated with the performance of traps (i.e. lure, trap design, placement) but also by an often poorly defined relationship between trap captures and population density. In this study, we analyzed multiple trapping data sets ...

High energy resolution measurement of the sup 238 U neutron capture yield from 1 to 100 keV

Energy Technology Data Exchange (ETDEWEB)

Macklin, R.L. (Tennessee Univ., Knoxville, TN (United States). Dept. of Nuclear Engineering); Perez, R.B. (Tennessee Univ., Knoxville, TN (United States). Dept. of Nuclear Engineering Oak Ridge National Lab., TN (United States)); De Saussure, G.; Ingle, R.W. (Oak Ridge National Lab., TN (United States))

1991-01-01

The purpose of this work is the precise determination of the {sup 238}U neutron capture yield (i.e. the probability of neutron capture) as a function of neutron energy with the highest available neutron energy resolution. The motivation for this undertaking arises from the central role played by the {sup 238}U neutron capture process in the neutron balance of both thermal reactors and fast breeder reactors. The present measurement was performed using the Oak Ridge Electron Linear Accelerator (ORELA) facility. The pulsed beam of neutrons from the ORELA facility is collimated on a sample of {sup 238}U. The neutron capture rate in the sample is measured, as a function of neutron time-of-flight (TOF) by detecting the {gamma}-rays from the {sup 238}U(n, {gamma}){sup 239}U reaction with a large {gamma}-ray detector surrounding the {sup 238}U sample. At each energy, the capture yield is proportional to the observed capture rate divided by the measured intensity of the neutron beam. The constant of proportionality (the normalization constant) is obtained from the ratio of theoretical to experimentally measured areas under small {sup 238}U resonances where the resonance parameters have been determined from high-resolution {sup 238}U transmission measurements. The cross section for the reaction {sup 238}U(n,{gamma}){sup 239}U can be derived from the measured capture yield if one applies appropriate corrections for multiple scattering and resonance self-shielding. Some 200 {sup 238}U neutron resonances in the energy range from 250 eV to 10 keV have been observed which had not been detected in previous measurements. (author).

Robust multiple frequency multiple power localization schemes in the presence of multiple jamming attacks.

Directory of Open Access Journals (Sweden)

Ahmed Abdulqader Hussein

Full Text Available Localization of the wireless sensor network is a vital area acquiring an impressive research concern and called upon to expand more with the rising of its applications. As localization is gaining prominence in wireless sensor network, it is vulnerable to jamming attacks. Jamming attacks disrupt communication opportunity among the sender and receiver and deeply impact the localization process, leading to a huge error of the estimated sensor node position. Therefore, detection and elimination of jamming influence are absolutely indispensable. Range-based techniques especially Received Signal Strength (RSS is facing severe impact of these attacks. This paper proposes algorithms based on Combination Multiple Frequency Multiple Power Localization (C-MFMPL and Step Function Multiple Frequency Multiple Power Localization (SF-MFMPL. The algorithms have been tested in the presence of multiple types of jamming attacks including capture and replay, random and constant jammers over a log normal shadow fading propagation model. In order to overcome the impact of random and constant jammers, the proposed method uses two sets of frequencies shared by the implemented anchor nodes to obtain the averaged RSS readings all over the transmitted frequencies successfully. In addition, three stages of filters have been used to cope with the replayed beacons caused by the capture and replay jammers. In this paper the localization performance of the proposed algorithms for the ideal case which is defined by without the existence of the jamming attack are compared with the case of jamming attacks. The main contribution of this paper is to achieve robust localization performance in the presence of multiple jamming attacks under log normal shadow fading environment with a different simulation conditions and scenarios.

Structure Determination of Anionic Metal Clusters via Infrared Resonance Enhanced Multiple Photon Electron Detachment Spectroscopy

NARCIS (Netherlands)

Haertelt, M.; Lapoutre, V. J. F.; Bakker, J. M.; Redlich, B.; Harding, D. J.; Fielicke, A.; Meijer, G.

2011-01-01

We report vibrational spectra of anionic metal clusters, measured via electron detachment following resonant absorption of multiple infrared photons. To facilitate the sequential absorption of the required large number of photons, the cluster beam interacts with the infrared radiation inside the

Possibility of resonant capture of antiprotons by highly charged hydrogenlike ions

International Nuclear Information System (INIS)

Genkin, M.; Lindroth, E.

2009-01-01

Recently, an experimental setup was proposed by Lapierre et al. which would allow antiprotons and highly charged ions to collide repeatedly in an electron beam ion trap (EBIT) due to a nested trap configuration. As mentioned by the authors, such a setup may open the possibility to study antiproton capture into well-defined states through a resonant process which involves simultaneous electron excitation. In the present work, we give some theoretical estimations of the feasibility of that process. It appears that the exotic dielectronic-like process of resonant anti-proton capture in highly charged ions does not seem to be completely out of reach

Electronics cooling of Phenix multiplicity and vertex detector

International Nuclear Information System (INIS)

Chen, Z.; Gregory, W.S.

1996-08-01

The Multiplicity and Vertex Detector (MVD) uses silicon strip sensors arranged in two concentric barrels around the beam pipe of the PHENIX detector that will be installed at Brookhaven National Laboratory. Each silicon sensor is connected by a flexible kapton cable to its own front-end electronics printed circuit board that is a multi-chip module or MCM. The MCMs are the main heat source in the system. To maintain the MVD at optimized operational status, the maximum temperature of the multi-chip modules must be below 40 C. Using COSMOS/M HSTAR for the Heat Transfer analysis, a finite element model of a typical MCM plate was created to simulate a 9m/s airflow and 9m/s mixed flow composed of 50% helium and 50% air respectively, with convective heat transfer on both sides of the plate. The results using a mixed flow of helium and air show that the average maximum temperature reached by the MCMs is 37.5 C. The maximum temperature which is represented by the hot spots on the MCM is 39.43 C for the helium and air mixture which meets the design temperature requirement 40 C. To maintain the Multiplicity and Vertex Detector at optimized operational status, the configuration of the plenum chamber, the power dissipated by the silicon chips, the fluid flow velocity and comparison on the MCM design parameters will be discussed

Single and multiple ionization of sulfur atoms by electron impact

International Nuclear Information System (INIS)

Ziegler, D.L.

1982-01-01

Laboratory measurements of the cross sections for single, double, triple, and quadruple ionization of sulfur atoms by electron impact are presented for collision energies from threshold to 500 eV. The cross sections for single ionization of sulfur are measured relative to those of several elements whose absolute cross sections for single ionization are known. Cross sections for each multiple ionization process are then measured relative to those for single ionization. The configuration and operation of the apparatus for these measurements are described. The possible effects of excited sulfur reactants are examined, and the reported cross sections are felt to be characteristic of ground state sulfur atoms

Photon multiplicity in the hard radiation of 150 GeV electrons in an aligned germanium crystal

International Nuclear Information System (INIS)

Belkacem, A.; Chevallier, M.; Gaillard, M.J.; Genre, R.; Kirsch, R.; Poizat, J.C.; Remillieux, J.; Bologna, G.; Peigneux, J.P.; Sillou, D.; Spighel, M.; Cue, N.; Kimball, J.C.; Marsh, B.B.; Sun, C.R.

1988-01-01

Mean values m of photon multiplicity in the radiation of 150 GeV electrons directed at and near the axis of a 0.185 mm thick Ge crystal cooled to 100 K have been deduced from the measurements of pair conversion probabilities. Depending on the distribution of multiplicity assumed, values of m ranging from 3.8 to 4.3 are obtained for the previously reported anomalous radiation peak. (orig.)

The origin of the Crab Nebula and the electron capture supernova in 8-10 M solar mass stars

Science.gov (United States)

Nomoto, K.

1981-01-01

The chemical composition of the Crab Nebula is compared with several presupernova models. The small carbon and oxygen abundances in the helium-rich nebula are consistent with only the presupernova model of the star whose main sequence mass was MMS approximately 8-9.5 M. More massive stars contain too much carbon in the helium layer and smaller mass stars do not leave neutron stars. The progenitor star of the Crab Nebula lost appreciable part of the hydrogen-rich envelope before the hydrogen-rich and helium layers were mixed by convection. Finally it exploded as the electron capture supernova; the O+Ne+Mg core collapsed to form a neutron star and only the extended helium-rich envelope was ejected by the weak shock wave.

One-electron capture into Li-like autoionising N/sup 4 +/ (1s2ln'l') configurations by metastable N/sup 5 +/ (1s2s/sup 3/S) multicharged ions in collisions with He and H/sub 2/, observed by electron spectrometry at 3. 4 keV amu/sup -1/

Energy Technology Data Exchange (ETDEWEB)

Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A.; Dousson, S.; Hitz, D.

1985-04-14

One-electron capture into N/sup 4 +/ (1s2ln'l') configurations, with n'=2 to 4, has been observed by electron spectrometry when a N/sup 5 +/ (1s2s /sup 3/S) multicharged ion beam encounters an He or H/sub 2/ target, at low collision velocity (upsilon=0.37 au) within single-collision conditions. Contributions of other 1s2l metastable states and of the 1s/sup 2/ ground state may be disregarded. A small indication of two-electron capture by 1s2s /sup 3/S ions into (1s2s /sup 3/S)3l3l' configurations is also seen.

The AtChem On-line model and Electronic Laboratory Notebook (ELN): A free community modelling tool with provenance capture

Science.gov (United States)

Young, J. C.; Boronska, K.; Martin, C. J.; Rickard, A. R.; Vázquez Moreno, M.; Pilling, M. J.; Haji, M. H.; Dew, P. M.; Lau, L. M.; Jimack, P. K.

2010-12-01

AtChem On-line1 is a simple to use zero-dimensional box modelling toolkit, developed for use by laboratory, field and chamber scientists. Any set of chemical reactions can be simulated, in particular the whole Master Chemical Mechanism (MCM2) or any subset of it. Parameters and initial data can be provided through a self-explanatory web form and the resulting model is compiled and run on a dedicated server. The core part of the toolkit, providing a robust solver for thousands of chemical reactions, is written in Fortran and uses SUNDIALS3 CVODE libraries. Chemical systems can be constrained at multiple, user-determined timescales; this enabled studies of radical chemistry at one minute timescales. AtChem On-line is free to use and requires no installation - a web browser, text editor and any compressing software is all the user needs. CPU and storage are provided by the server (input and output data are saved indefinitely). An off-line version is also being developed, which will provide batch processing, an advanced graphical user interface and post-processing tools, for example, Rate of Production Analysis (ROPA) and chainlength analysis. The source code is freely available for advanced users wishing to adapt and run the program locally. Data management, dissemination and archiving are essential in all areas of science. In order to do this in an efficient and transparent way, there is a critical need to capture high quality metadata/provenance for modelling activities. An Electronic Laboratory Notebook (ELN) has been developed in parallel with AtChem Online as part of the EC EUROCHAMP24 project. In order to use controlled chamber experiments to evaluate the MCM, we need to be able to archive, track and search information on all associated chamber model runs, so that they can be used in subsequent mechanism development. Therefore it would be extremely useful if experiment and model metadata/provenance could be easily and automatically stored electronically

Electronic data capture in a rural African setting: evaluating experiences with different systems in Malawi.

Science.gov (United States)

King, Carina; Hall, Jenny; Banda, Masford; Beard, James; Bird, Jon; Kazembe, Peter; Fottrell, Ed

2014-01-01

As hardware for electronic data capture (EDC), such as smartphones or tablets, becomes cheaper and more widely available, the potential for using such hardware as data capture tools in routine healthcare and research is increasing. We aim to highlight the advantages and disadvantages of four EDC systems being used simultaneously in rural Malawi: two for Android devices (CommCare and ODK Collect), one for PALM and Windows OS (Pendragon), and a custom-built application for Android (Mobile InterVA--MIVA). We report on the personal field and development experience of fieldworkers, project managers, and EDC system developers. Fieldworkers preferred using EDC to paper-based systems, although some struggled with the technology at first. Highlighted features include in-built skip patterns for all systems, and specifically the 'case' function that CommCare offers. MIVA as a standalone app required considerably more time and expertise than the other systems to create and could not be customised for our specific research needs; however, it facilitates standardised routine data collection. CommCare and ODK Collect both have user-friendly web-interfaces for form development and good technical support. CommCare requires Internet to build an application and download it to a device, whereas all steps can be done offline with ODK Collect, a desirable feature in low connectivity settings. Pendragon required more complex programming of logic, using a Microsoft Access application, and generally had less technical support. Start-up costs varied between systems, and all were considered more expensive than setting up a paper-based system; however running costs were generally low and therefore thought to be cost-effective over the course of our projects. EDC offers many opportunities for efficient data collection, but brings some issues requiring consideration when designing a study; the decision of which hardware and software to use should be informed by the aim of data collection

Investigation by high resolution electron spectroscopy of the helium-like 3lnl' Rydberg series in double capture processes at low collision velocity: auto transfer to Rydberg states and electron stabilization

Energy Technology Data Exchange (ETDEWEB)

Bordenave-Montesquieu, A.; Moretto-Capelle, P.; Gonzalez, A.; Benhenni, M. (Toulouse-3 Univ., 31 (France)); Bachau, H.; Sanchez, I. (Bordeaux-1 Univ., 33 - Talence (France). Lab. des Collisions Atomiques)

1994-09-28

A high resolution electron spectrometry of the (3lnl') Ryberg series populated in N[sup 7+] + He and Ne[sup 10+] + He collisions at 10 q keV, 10[sup o] allows us to observe, for the first time by this method, two post-collisional effects. First, it is found with nitrogen ions that, when n increases from n = 4 to 9, the L-distribution peaks more and more on the high angular momentum states. This is qualitatively understood as a Stark deformation of the Rydberg orbit by the Coulomb field of the receding ion. Also, in the n range where the double capture process populates symmetrical 4l4l' states (n>9), an enhancement of the intensities of the 3lnl' Rydberg lines is observed for both collisonal systems. This is thought to be a signature of the so-called auto transfer to Rydberg states effect. The transfer of population from the 3l4l' to the 3lnl' states is found to be favoured against a direct autoionization of these 4l4l' states into the n = 2 continuum. These experimental findings together with preliminary spectroscopic calculations concerning the configuration interaction of the Ne[sup 8+] (4l4l') states with the Ne[sup 8+](3lnl') Rydberg series are also discussed within the context of the electron stabilization which follows a double capture. (Author).

Design of equipment for the detection of nickel-63 source of the gc-2010 electron capture detector

International Nuclear Information System (INIS)

Lopez O, A.

2016-01-01

It is necessary to design a system that is able to detect the presence of the radioactive source nickel-63, located within the electron capture detector gc- 2010 through the use of Arduino technology, presence sensors and motion This in turn It must be interfaced with a system of tracking and tracing , so collectively be mounted inside the mobile laboratory for research and technological development of systems and equipment for measuring radiation , gases and particles. The program has a structure reading sensors, processing the acquired data and execution of an action if necessary. The system does this by receiving data autonomously, the data is processed and at the end, determines whether the source is in normal operating conditions, if subjected to movements that may cause undesired operation if being handled, or has it has been extracted. (Author)

Towards saturation of the electron-capture delayed fission probability: The new isotopes 240Es and 236Bk

Directory of Open Access Journals (Sweden)

J. Konki

2017-01-01

Full Text Available The new neutron-deficient nuclei 240Es and 236Bk were synthesised at the gas-filled recoil separator RITU. They were identified by their radioactive decay chains starting from 240Es produced in the fusion–evaporation reaction 209Bi(34S,3n240Es. Half-lives of 6(2s and 22−6+13s were obtained for 240Es and 236Bk, respectively. Two groups of α particles with energies Eα=8.19(3MeV and 8.09(3MeV were unambiguously assigned to 240Es. Electron-capture delayed fission branches with probabilities of 0.16(6 and 0.04(2 were measured for 240Es and 236Bk, respectively. These new data show a continuation of the exponential increase of ECDF probabilities in more neutron-deficient isotopes.

Coulomb Blockade and Multiple Andreev Reflection in a Superconducting Single-Electron Transistor

Science.gov (United States)

Lorenz, Thomas; Sprenger, Susanne; Scheer, Elke

2018-06-01

In superconducting quantum point contacts, multiple Andreev reflection (MAR), which describes the coherent transport of m quasiparticles each carrying an electron charge with m≥3, sets in at voltage thresholds eV = 2Δ /m. In single-electron transistors, Coulomb blockade, however, suppresses the current at low voltage. The required voltage for charge transport increases with the square of the effective charge eV∝ ( me) ^2. Thus, studying the charge transport in all-superconducting single-electron transistors (SSETs) sets these two phenomena into competition. In this article, we present the fabrication as well as a measurement scheme and transport data for a SSET with one junction in which the transmission and thereby the MAR contributions can be continuously tuned. All regimes from weak to strong coupling are addressed. We extend the Orthodox theory by incorporating MAR processes to describe the observed data qualitatively. We detect a new transport process the nature of which is unclear at present. Furthermore, we observe a renormalization of the charging energy when approaching the strong coupling regime.

Distorted wave calculations for double electron transfer

International Nuclear Information System (INIS)

Martinez, A.E.; Rivarola, R.D.; Gayet, R.; Hanssen, J.

1992-01-01

The resonant double electron capture by alpha particles in helium targets is studied, at intermediate and high collision energies, using the Continuum Distorted Wave - Eikonal Initial State (CDW-EIS) model. Differential and total cross sections for capture into the He (1 s 2 ) final state are calculated in the framework of an Independent Electron Approximation (IEA). Theoretical results are compared with the experimental data available at present for capture into any final state of helium. (author)

Electron correlation in single-electron capture from helium by fast protons

International Nuclear Information System (INIS)

Purkait, M

2012-01-01

The differential and total cross sections for single charge exchange in p-He collisions have been calculated within the framework of four-body boundary corrected continuum intermediate state (BCCIS-4B) approximation. The effect of dynamic electron correlations is explicitly taken into account through the complete perturbation potentials.

Assessment of pesticide residues in some fruits using gas chromatography coupled with micro electron capture detector

International Nuclear Information System (INIS)

Latif, Y.; Sherazi, S.T.H.; Bhanger, M.I.

2011-01-01

A very sensitive analytical method for the determination of 26 pesticides in some fruits based on solid phase extraction (SPE) cleanup was developed using gas chromatography (GC) coupled with micro electron capture detector (mu ECD). The identity of the pesticides was confirmed by gas chromatography mass spectroscopy (GC-MS) using selected ion monitoring (SIM) mode. Ethyl acetate was used as a solvent for the extraction of pesticide residues with assistance of sonication. For cleanup an octadecyl, C18 SPE column was used. A linear response of mu ECD was observed for all pesticides with good correlation coefficients (>0.9992). Proposed method was successfully applied for the determination of pesticide residues in the orange, apple, and grape fruits. Average recoveries achieved for all of the pesticides at fortification levels of 0.05, 1.0 and 2.0 mu g g/sup -1/ in analyzed fruits were above 90% with relative standard deviations (RSD) less than 6%. (author)

Assessment of Pesticide Residues in Some Fruits Using Gas Chromatography Coupled with Micro Electron Capture Detector

Directory of Open Access Journals (Sweden)

M. I. Bhanger

2011-12-01

Full Text Available A very sensitive analytical method for the determination of 26 pesticides in some fruits based on solid phase extraction (SPE cleanup was developed using gas chromatography (GC coupled with micro electron capture detector (μECD. The identity of the pesticides was confirmed by gas chromatography mass spectroscopy (GC-MS using selected ion monitoring (SIM mode. Ethyl acetate was used as a solvent for the extraction of pesticide residues with assistance of sonication. For cleanup an octadecyl, C18 SPE column was used. A linear response of μECD was observed for all pesticides with good correlation coefficients (>0.9992. Proposed method was successfully applied for the determination of pesticide residues in the orange, apple, and grape fruits. Average recoveries achieved for all of the pesticides at fortification levels of 0.05, 1.0 and 2.0 μg g-1 in analyzed fruits were above 90% with relative standard deviations (RSD less than 6

Implementing electronic data capture at a well-established health and demographic surveillance site in rural northern Malawi

OpenAIRE

McLean, Estelle; Dube, Albert; Saul, Jacky; Branson, Keith; Luhanga, Mabvuto; Mwiba, Oddie; Kalobekamo, Fredrick; Geis, Steffen; Crampin, Amelia C

2017-01-01

ABSTRACT This article aims to assess multiple issues of resources, staffing, local opinion, data quality, cost, and security while transitioning to electronic data collection (EDC) at a long-running community research site in northern Malawi. Levels of missing and error fields, delay from data collection to availability, and average number of interviews per day were compared between EDC and paper in a complex, repeated annual household survey. Three focus groups with field and data staff with...

Experimental study on pion capture by hydrogen bound in molecules

International Nuclear Information System (INIS)

Horvath, D.; Aniol, K.A.; Entezami, F.; Measday, D.F.; Noble, A.J.; Stanislaus, S.; Virtue, C.J.

1988-08-01

An experiment was performed at TRIUMF to study the formation of pionic hydrogen atoms and molecules in solids, particularly in groups of organic molecules of slightly different structure in order to help further clarify the problem. The nuclear capture of pions by hydrogen was measured using the charge exchange of stopped pions. The coincident photons emitted by the decaying π 0 mesons were detected by TRIUMF's two large NaI spectrometers. New experimental results were obtained for the capture probability of stopped π - mesons in the nuclei of hydrogen atoms, chemically bound in molecules of some simple hydrides, acid anhydrides, and sugar isomers. A linear relation was found between pion capture in hydrogen and melting point in sugar isomers. The pion capture probability in acid anhydrides is fairly well described by a simple atomic capture model in which the capture probability on the hydrogen dramatically increases as the hydrogen atom is separated from the strongly electronegative C 2 O 3 group. Both effects are consistent with a correlation between pion capture and electron density on hydrogen atoms. (Author) (38 refs., 4 tabs., 7 figs.)

Contingent capture effects in temporal order judgments.

Science.gov (United States)

Born, Sabine; Kerzel, Dirk; Pratt, Jay

2015-08-01

The contingent attentional capture hypothesis proposes that visual stimuli that do not possess characteristics relevant for the current task will not capture attention, irrespective of their bottom-up saliency. Typically, contingent capture is tested in a spatial cuing paradigm, comparing manual reaction times (RTs) across different conditions. However, attention may act through several mechanisms and RTs may not be ideal to disentangle those different components. In 3 experiments, we examined whether color singleton cues provoke cuing effects in temporal order judgments (TOJs) and whether they would be contingent on attentional control sets. Experiment 1 showed that color singleton cues indeed produce cuing effects in TOJs, even in a cluttered and dynamic target display containing multiple heterogeneous distractors. In Experiment 2, consistent with contingent capture, we observed reliable cuing effects only when the singleton cue matched participants' current attentional control set. Experiment 3 suggests that a sensory interaction account of the differences found in Experiment 2 is unlikely. Our results help to discern the attentional components that may play a role in contingent capture. Further, we discuss a number of other effects (e.g., reversed cuing effects) that are found in RTs, but so far have not been reported in TOJs. Those differences suggest that RTs are influenced by a multitude of mechanisms; however, not all of these mechanisms may affect TOJs. We conclude by highlighting how the study of attentional capture in TOJs provides valuable insights for the attention literature, but also for studies concerned with the perceived timing between stimuli. (c) 2015 APA, all rights reserved).

Laser-Induced Graphene by Multiple Lasing: Toward Electronics on Cloth, Paper, and Food.

Science.gov (United States)

Chyan, Yieu; Ye, Ruquan; Li, Yilun; Singh, Swatantra Pratap; Arnusch, Christopher J; Tour, James M

2018-03-27

A simple and facile method for obtaining patterned graphene under ambient conditions on the surface of diverse materials ranging from renewable precursors such as food, cloth, paper, and cardboard to high-performance polymers like Kevlar or even on natural coal would be highly desirable. Here, we report a method of using multiple pulsed-laser scribing to convert a wide range of substrates into laser-induced graphene (LIG). With the increased versatility of the multiple lase process, highly conductive patterns can be achieved on the surface of a diverse number of substrates in ambient atmosphere. The use of a defocus method results in multiple lases in a single pass of the laser, further simplifying the procedure. This method can be implemented without increasing processing times when compared with laser induction of graphene on polyimide (Kapton) substrates as previously reported. In fact, any carbon precursor that can be converted into amorphous carbon can be converted into graphene using this multiple lase method. This may be a generally applicable technique for forming graphene on diverse substrates in applications such as flexible or even biodegradable and edible electronics.

Cusp and W peak analysis in electron capture to the continuum of bare H and He projectiles from hydrocarbon and fluorocarbon gases

Energy Technology Data Exchange (ETDEWEB)

Joyce, J.M.; Bissinger, G.

1987-04-01

The ECC cusp and W peak shapes for continuum electron capture by approx. = MeV/u H/sup +/ and He/sup 2 +/ from hydrocarbon and fluorocarbon gas molecules are analyzed with the general parametric expression of Meckbach, Nemirovsky and Garibotti (i) to look for trends in the coefficients of these parameters, (ii) as a way of generating computed cusp shapes to reduce statistical fluctuations in cusp difference spectra, and (iii) to provide information on the deconvoluted d/sup 2/sigma/d..nu.. dtheta values for cusp and W peaks in the hydrocarbon gases.

Method to map one-dimensional electronic wave function by using multiple Brillouin zone angle resolved photoemission

Directory of Open Access Journals (Sweden)

Dong-Wook Lee

2010-10-01

Full Text Available Angle resolved photoemission spectroscopy (ARPES is a powerful tool to investigate electronic structures in solids and has been widely used in studying various materials. The electronic structure information by ARPES is obtained in the momentum space. However, in the case of one-dimensional system, we here show that we extract the real space information from ARPES data taken over multiple Brillouin zones (BZs. Intensities in the multiple BZs are proportional to the photoemission matrix element which contains information on the coefficient of the Bloch wave function. It is shown that the Bloch wave function coefficients can be extracted from ARPES data, which allows us to construct the real space wave function. As a test, we use ARPES data from proto-typical one-dimensional system SrCuO2 and construct the real space wave function.

Mobile Device-Based Electronic Data Capture System Used in a Clinical Randomized Controlled Trial: Advantages and Challenges.

Science.gov (United States)

Zhang, Jing; Sun, Lei; Liu, Yu; Wang, Hongyi; Sun, Ningling; Zhang, Puhong

2017-03-08

Electronic data capture (EDC) systems have been widely used in clinical research, but mobile device-based electronic data capture (mEDC) system has not been well evaluated. The aim of our study was to evaluate the feasibility, advantages, and challenges of mEDC in data collection, project management, and telemonitoring in a randomized controlled trial (RCT). We developed an mEDC to support an RCT called "Telmisartan and Hydrochlorothiazide Antihypertensive Treatment (THAT)" study, which was a multicenter, double-blinded, RCT, with the purpose of comparing the efficacy of telmisartan and hydrochlorothiazide (HCTZ) monotherapy in high-sodium-intake patients with mild to moderate hypertension during a 60 days follow-up. Semistructured interviews were conducted during and after the trial to evaluate the feasibility, advantage, and challenge of mEDC. Nvivo version 9.0 (QSR International) was used to analyze records of interviews, and a thematic framework method was used to obtain outcomes. The mEDC was successfully used to support the data collection and project management in all the 14 study hospitals. A total of 1333 patients were recruited with support of mEDC, of whom 1037 successfully completed all 4 visits. Across all visits, the average time needed for 141 questions per patient was 53 min, which were acceptable to both doctors and patients. All the interviewees, including 24 doctors, 53 patients, 1 clinical research associate (CRA), 1 project manager (PM), and 1 data manager (DM), expressed their satisfaction to nearly all the functions of the innovative mEDC in randomization, data collection, project management, quality control, and remote monitoring in real time. The average satisfaction score was 9.2 (scale, 0-10). The biggest challenge came from the stability of the mobile or Wi-Fi signal although it was not a problem in THAT study. The innovative mEDC has many merits and is well acceptable in supporting data collection and project management in a timely

Differential Single-Capture Cross Sections for Fast Alpha–Helium Collisions

International Nuclear Information System (INIS)

Ghanbari-Adivi, Ebrahim; Ghavaminia, Hoda

2014-01-01

A four-body theoretical study of the single charge transfer process in collision of energetic alpha ions with helium atoms in their ground states is presented. The model utilizes the Coulomb–Born distorted wave approximation with correct boundary conditions to calculate the single-electron capture differential and integral cross sections. The influence of the dynamic and static electron correlations on the capture probability is investigated. The results of the calculations are compared with the recent experimental measurements for differential cross sections and with the other theoretical manipulations. The results for scattering at extreme forward angles are in good agreement with the experimental measurements, but in other scattering angles the agreement is poor. However, the present four-body results for integral cross sections are in excellent agreement with the experimental data. (author)

Evaluation of capture techniques for long-billed curlews wintering in Texas

Science.gov (United States)

Woodin, Marc C.; Skoruppa, Mary K.; Edwardson, Jeremy W.; Austin, Jane E.

2012-01-01

Texas coast harbors the largest, eastern-most populations of Long-billed Curlews (Numenius americanus) in North America; however, very little is known about their migration and wintering ecology. Curlews are readily captured on their breeding grounds, but experience with capturing the species during the non-breeding season is extremely limited. We assessed the efficacy of 6 capture techniques for Long-billed Curlews in winter: 1) modified noose ropes, 2) remotely controlled bow net, 3) Coda Netgun, 4) Super Talon net gun, 5) Hawkseye whoosh net, and 6) cast net. The Coda Netgun had the highest rate of captures per unit of effort (CPUE = 0.31; 4 curlew captures/13 d of trapping effort), followed by bow net (CPUE = 0.17; 1 capture/6 d of effort), whoosh net (CPUE = 0.14; 1 capturel7 d of effort), and noose ropes (CPUE = 0.07; 1 capturel15 d of effort). No curlews were captured using the Super Talon net gun or a cast net (3 d and 1 d of effort, respectively). Multiple capture techniques should be readily available for maximum flexibility in matching capture methods with neophobic curlews that often unpredictably change referred feeding locations among extremely different habitat types.

A Novel Feature Extraction Approach Using Window Function Capturing and QPSO-SVM for Enhancing Electronic Nose Performance

Directory of Open Access Journals (Sweden)

Xiuzhen Guo

2015-06-01

Full Text Available In this paper, a novel feature extraction approach which can be referred to as moving window function capturing (MWFC has been proposed to analyze signals of an electronic nose (E-nose used for detecting types of infectious pathogens in rat wounds. Meanwhile, a quantum-behaved particle swarm optimization (QPSO algorithm is implemented in conjunction with support vector machine (SVM for realizing a synchronization optimization of the sensor array and SVM model parameters. The results prove the efficacy of the proposed method for E-nose feature extraction, which can lead to a higher classification accuracy rate compared to other established techniques. Meanwhile it is interesting to note that different classification results can be obtained by changing the types, widths or positions of windows. By selecting the optimum window function for the sensor response, the performance of an E-nose can be enhanced.

Neutron Capture and Transmission Measurements and Resonance Parameter Analysis of Niobium

International Nuclear Information System (INIS)

NJ Drindak; JA Burke; G Leinweber; JA Helm; JG Hoole; RC Block; Y Danon; RE Slovacek; BE Moretti; CJ Werner; ME Overberg; SA Kolda; MJ Trbovich; DP Barry

2005-01-01

Epithermal neutron capture and transmission measurements were performed using the time-of-flight method at the RPI linac using metallic Nb samples. The capture measurements were made at the 25-meter flight station with a 16-section sodium iodide multiplicity detector and the transmission measurements at the 25-meter flight station with a Li-6 glass scintillation detector. Resonance parameters were determined for all resonances up to 500eV with a combined analysis of capture and transmission data using the multi-level R-matrix Bayesian code SAMMY. The present results are compared to those presented in ENDF/B-VI, updated through Release 3

Spectroscopic Diagnosis of Excited-State Aromaticity: Capturing Electronic Structures and Conformations upon Aromaticity Reversal.

Science.gov (United States)

Oh, Juwon; Sung, Young Mo; Hong, Yongseok; Kim, Dongho

2018-03-06

scrutinize this intriguing and challenging scientific issue, expanded porphyrins have been utilized as the ideal testing platform for investigating aromaticity because they show distinct aromatic and antiaromatic characters with aromaticity-specific spectroscopic features. Expanded porphyrins exhibit perfect aromatic and antiaromatic congener pairs having the same molecular framework but different numbers of π electrons, which facilitates the study of the pure effect of aromaticity by comparative analyses. On the basis of the characteristics of expanded porphyrins, time-resolved electronic and vibrational absorption spectroscopies capture the changes in electronic structure and molecular conformations driven by the change in aromaticity and provide clear evidence for aromaticity reversal in the excited states. The approaches described in this Account pave the way for the development of new and alternative experimental indices for the evaluation of excited-state aromaticity, which will enable overarching and fundamental comprehension of the role of (anti)aromaticity in the stability, dynamics, and reactivity in the excited states with possible implications for practical applications.

Electronic transport in single-helical protein molecules: Effects of multiple charge conduction pathways and helical symmetry

Energy Technology Data Exchange (ETDEWEB)

Kundu, Sourav, E-mail: sourav.kunduphy@gmail.com; Karmakar, S.N.

2016-07-15

We propose a tight-binding model to investigate electronic transport properties of single helical protein molecules incorporating both the helical symmetry and the possibility of multiple charge transfer pathways. Our study reveals that due to existence of both the multiple charge transfer pathways and helical symmetry, the transport properties are quite rigid under influence of environmental fluctuations which indicates that these biomolecules can serve as better alternatives in nanoelectronic devices than its other biological counterparts e.g., single-stranded DNA.

Dependence of Xmax and multiplicity of electron and muon on different high energy interaction models

Directory of Open Access Journals (Sweden)

G Rastegarzadeh

2010-06-01

Full Text Available Different high energy interaction models are the applied in CORSIKA code to simulate Extensive Air Showers (EAS generated by Cosmic Rays (CR. In this work the effects of QGSJET01, QGSJETII, DPMJET, SIBYLL models on Xmax and multiplicity of secondary electrons and muons at observation level are studied.

Lack of magnetic resonance imaging lesion activity as a treatment target in multiple sclerosis: An evaluation using electronically collected outcomes.

Science.gov (United States)

Conway, Devon S; Thompson, Nicolas R; Cohen, Jeffrey A

2016-09-01

The appropriate treatment target in multiple sclerosis (MS) is unclear. Lack of magnetic resonance imaging (MRI) lesion activity, a component of the no evidence of disease activity concept, has been proposed as a treatment target in MS. We used our MS database to investigate whether aggressively pursuing MRI stability by changing disease modifying therapy (DMT) when MRI activity is observed leads to better clinical and imaging outcomes. The Knowledge Program (KP) is a database linked to our electronic medical record allowing capture of patient and clinician reported outcomes. Through KP query and chart review, we identified all relapsing-remitting MS patients visiting between 1 January 2008 and 31 December 2014 with active MRIs despite DMT. Propensity modeling based on demographic and disease characteristics was used to match DMT switchers to non-switchers. KP and MRI outcomes were compared 18 months after the active MRI using mixed-effects linear regression models. We identified 417 patients who met criteria for our analysis. After propensity matching, 78 switchers and 91 non-switchers were analyzed. There was no difference in clinical or radiologic outcomes between these groups at 18 months. We did not find a short-term benefit of changing DMT to pursue MRI stability. Copyright © 2016 Elsevier B.V. All rights reserved.

Electron attachment cross sections obtained from electron attachment spectroscopy

International Nuclear Information System (INIS)

Popp, P.; Baumbach, J.I.; Leonhardt, J.W.; Mothes, S.

1988-01-01

Electron capture detectors have a high sensitivity for substances with high thermal electron attachment cross sections. The electron attachment spectroscopy makes it possible to change the mean electron energy in such a way that the maximum for dissociative electron attachment is reached. Thus, best operation modes of the detection system as well as significant dependencies of electron attachment coefficients are available. Cross sections for electron attachment as a function of the electron energy are obtained with the knowledge of electron energy distribution functions from Boltzmann equation analysis by a special computer code. A disadvantage of this electron attachment spectroscopy is the superposition of space charge effects due to the decrease of the electron drift velocity with increasing mean electron energy. These influences are discussed. (author)

Multiplexed evaluation of capture agent binding kinetics using arrays of silicon photonic microring resonators.

Science.gov (United States)

Byeon, Ji-Yeon; Bailey, Ryan C

2011-09-07

High affinity capture agents recognizing biomolecular targets are essential in the performance of many proteomic detection methods. Herein, we report the application of a label-free silicon photonic biomolecular analysis platform for simultaneously determining kinetic association and dissociation constants for two representative protein capture agents: a thrombin-binding DNA aptamer and an anti-thrombin monoclonal antibody. The scalability and inherent multiplexing capability of the technology make it an attractive platform for simultaneously evaluating the binding characteristics of multiple capture agents recognizing the same target antigen, and thus a tool complementary to emerging high-throughput capture agent generation strategies.

Neutron Capture and Transmission Measurements and Resonance Parameter Analysis of Samarium

International Nuclear Information System (INIS)

Leinweber, G.; Burke, J.A.; Knox, H.D.; Drindak, N.J.; Mesh, D.W.; Haines, W.T.; Ballad, R.V.; Block, R.C.; Slovacek, R.E.; Werner, C.J.; Trbovich, M.J.; Barry, D.P.; Sato, T.

2001-01-01

The purpose of the present work is to accurately measure the neutron cross sections of samarium. The most significant isotope is 149 Sm, which has a large neutron absorption cross section at thermal energies and is a 235 U fission product with a 1% yield. Its cross sections are thus of concern to reactor neutronics. Neutron capture and transmission measurements were performed by the time-of-flight technique at the Rensselaer Polytechnic institute (RPI) LINAC facility using metallic and liquid Sm samples. The capture measurements were made at the 25 meter flight station with a multiplicity-type capture detector, and the transmission total cross-section measurements were performed at 15- and 25-meter flight stations with 6 Li glass scintillation detectors. Resonance parameters were determined by a combined analysis of six experiments (three capture and three transmission) using the multi-level R-matrix Bayesian code SAMMY version M2. The significant features of this work are as follows. Dilute samples of samarium nitrate in deuterated water (D 2 O) were prepared to measure the strong resonances at 0.1 and 8 eV without saturation. Disk-shaped spectroscopic quartz cells were obtained with parallel inner surfaces to provide a uniform thickness of solution. The diluent feature of the SAMMY program was used to analyze these data. The SAMMY program also includes multiple scattering corrections to capture yield data and resolution functions specific to the RPI facility. Resonance parameters for all stable isotopes of samarium were deduced for all resonances up to 30 eV. Thermal capture cross-section and capture resonance integral calculations were made using the resultant resonance parameters and were compared to results obtained using resonance parameters from ENDF/B-VI updated through release 3. Extending the definition of the capture resonance integral to include the strong 0.1 eV resonance in 149 Sm, present measurements agree within estimated uncertainties with En

Managing electronic records

CERN Document Server

McLeod, Julie

2005-01-01

For records management courses, this book covers the theory and practice of managing electronic records as business and information assets. It focuses on the strategies, systems and procedures necessary to ensure that electronic records are appropriately created, captured, organized and retained over time to meet business and legal requirements.

Humin as an electron donor for enhancement of multiple microbial reduction reactions with different redox potentials in a consortium.

Science.gov (United States)

Zhang, Dongdong; Zhang, Chunfang; Xiao, Zhixing; Suzuki, Daisuke; Katayama, Arata

2015-02-01

A solid-phase humin, acting as an electron donor, was able to enhance multiple reductive biotransformations, including dechlorination of pentachlorophenol (PCP), dissimilatory reduction of amorphous Fe (III) oxide (FeOOH), and reduction of nitrate, in a consortium. Humin that was chemically reduced by NaBH4 served as an electron donor for these microbial reducing reactions, with electron donating capacities of 0.013 mmol e(-)/g for PCP dechlorination, 0.15 mmol e(-)/g for iron reduction, and 0.30 mmol e(-)/g for nitrate reduction. Two pairs of oxidation and reduction peaks within the humin were detected by cyclic voltammetry analysis. 16S rRNA gene sequencing-based microbial community analysis of the consortium incubated with different terminal electron acceptors, suggested that Dehalobacter sp., Bacteroides sp., and Sulfurospirillum sp. were involved in the PCP dechlorination, dissimilatory iron reduction, and nitrate reduction, respectively. These findings suggested that humin functioned as a versatile redox mediator, donating electrons for multiple respiration reactions with different redox potentials. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Modeling misidentification errors that result from use of genetic tags in capture-recapture studies

Science.gov (United States)

Yoshizaki, J.; Brownie, C.; Pollock, K.H.; Link, W.A.

2011-01-01

Misidentification of animals is potentially important when naturally existing features (natural tags) such as DNA fingerprints (genetic tags) are used to identify individual animals. For example, when misidentification leads to multiple identities being assigned to an animal, traditional estimators tend to overestimate population size. Accounting for misidentification in capture-recapture models requires detailed understanding of the mechanism. Using genetic tags as an example, we outline a framework for modeling the effect of misidentification in closed population studies when individual identification is based on natural tags that are consistent over time (non-evolving natural tags). We first assume a single sample is obtained per animal for each capture event, and then generalize to the case where multiple samples (such as hair or scat samples) are collected per animal per capture occasion. We introduce methods for estimating population size and, using a simulation study, we show that our new estimators perform well for cases with moderately high capture probabilities or high misidentification rates. In contrast, conventional estimators can seriously overestimate population size when errors due to misidentification are ignored. ?? 2009 Springer Science+Business Media, LLC.

Searches for massive neutrino emission in 14C beta and 55Fe electron-capture decays

International Nuclear Information System (INIS)

Wietfeldt, F.E.

1994-05-01

In 1985 Simpson reported evidence for the emission of a 17 keV mass neutrino in a small fraction of tritium beta decays. An experimental controversy ensued in which a number of both positive and negative results were reported. The beta spectrum of 14 C was collected in a unique 14 C-doped planar germanium detector and a distortion was observed that initially confirmed Simpson's result. Further tests linked this distortion to a splitting of the collected charge between the central detector and the surrounding guard ring in a fraction of the events. A second 14 C measurement showed no evidence for emission of a 17 keV mass neutrino. In a related experiment, a high statistics electron-capture internal-bremsstrahlung photon spectrum of 55 Fe was collected with a coaxial germanium detector. A local search for departures from a smooth shape near the endpoint was performed, using a second-derivative technique. An upper limit of 0.65% (95% C.L.) for the mixing Of a neutrino in the mass range 5--25 keV was established. The upper limit on the mixing of a 17 keV mass neutrino was 0.14% (95% C.L.)

Two-electron capture into autoionising configurations N/sup 4 +/(1snln'l') with n = 2,3,4 and n' >= n, observed by electron spectrometry in collisions of N/sup 6 +/(1s) with He and H/sub 2/, at 4. 2 keV amu/sup -1/

Energy Technology Data Exchange (ETDEWEB)

Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A.; Marrakchi, A.I.; Dousson, S.; Hitz, D.

1984-04-14

Double electron transfer into autoionising states N/sup 4 +/(1snln'l'), with n = 2,3,4 and n' >= n has been observed in a collision between a one-electron highly charged N/sup 6 +/(1s) ion and a two-electron target (He or H/sub 2/), by electron spectrometry. The same configurations are excited in the two collisional systems but with very different probabilities. Electron capture mainly occurs into 1s2ln'l' in He-systems whereas transfer into 1s3ln'l' is stronger in H/sub 2/ systems.