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Sample records for charge exchange spectroscopy

  1. Charge exchange spectroscopy as a fast ion diagnostic on TEXTOR

    NARCIS (Netherlands)

    Delabie, E.; Jaspers, R. J. E.; von Hellermann, M. G.; Nielsen, S.K.; Marchuk, O.

    2008-01-01

    An upgraded charge exchange spectroscopy diagnostic has been taken into operation at the TEXTOR tokamak. The angles of the viewing lines with the toroidal magnetic field are close to the pitch angles at birth of fast ions injected by one of the neutral beam injectors. Using another neutral beam for

  2. Charge exchange spectroscopy as a fast ion diagnostic on TEXTOR

    DEFF Research Database (Denmark)

    Delabie, E.; Jaspers, R.J.E.; von Hellermann, M.G.;

    2008-01-01

    active spectroscopy, injected counter the direction in which fast ions injected by the first beam are circulating, we can simultaneously measure a fast ion tail on the blue wing of the D-alpha spectrum while the beam emission spectrum is Doppler shifted to the red wing. An analysis combining the two......An upgraded charge exchange spectroscopy diagnostic has been taken into operation at the TEXTOR tokamak. The angles of the viewing lines with the toroidal magnetic field are close to the pitch angles at birth of fast ions injected by one of the neutral beam injectors. Using another neutral beam for...... parts of the spectrum offers possibilities to improve the accuracy of the absolute (fast) ion density profiles. Fast beam modulation or passive viewing lines cannot be used for background subtraction on this diagnostic setup and therefore the background has to be modeled and fitted to the data together...

  3. Charge exchange recombination spectroscopy on the T-10 tokamak.

    Science.gov (United States)

    Klyuchnikov, L A; Krupin, V A; Nurgaliev, M R; Korobov, K V; Nemets, A R; Dnestrovskij, A Yu; Tugarinov, S N; Serov, S V; Naumenko, N N

    2016-05-01

    The charge exchange recombination spectroscopy (CXRS) diagnostics on the T-10 tokamak is described. The system is based on a diagnostic neutral beam and includes three high etendue spectrometers designed for the ITER edge CXRS system. A combined two-channel spectrometer is developed for simultaneous measurements of two beam-induced spectral lines using the same lines of sight. A basic element of the combined spectrometer is a transmitting holographic grating designed for the narrow spectral region 5291 ± 100 Å. The whole CXRS system provides simultaneous measurements of two CXRS impurity spectra and Hα beam line. Ion temperature measurements are routinely provided using the C(6+) CXRS spectral line 5291 Å. Simultaneous measurements of carbon densities and one more impurity (oxygen, helium, lithium etc.) are carried out. Two light collecting systems with 9 lines of sight in each system are used in the diagnostics. Spatial resolution is up to 2.5 cm and temporal resolution of 1 ms is defined by the diagnostic neutral beam diameter and pulse duration, respectively. Experimental results are shown to demonstrate a wide range of the CXRS diagnostic capabilities on T-10 for investigation of impurity transport processes in tokamak plasma. Developed diagnostics provides necessary experimental data for studying of plasma electric fields, heat and particle transport processes, and for investigation of geodesic acoustic modes. PMID:27250422

  4. X-UV SPECTROSCOPY OF LOW ENERGY CHARGE EXCHANGE COLLISIONS

    OpenAIRE

    Bliman, S.; Bonnet, J.; Bonnefoy, M.; Dousson, S.; Fleury, A.; Hitz, D.; Lu Dac, T.; Mayo, M.

    1986-01-01

    In the field of hot plasmas, it is well known that a knowledge of the relation between collisions and radiation is needed. We show that considering the charge exchange process in which a highly charged, low velocity ion impinges on an atom, we have an X-UV light source allowing new developments. Basically, at velocities less than the atomic unit (vo = 2.2 108 cm/s), the capture of one electron will leave the projectile ion in an excited state. The most probably populated level np is dependant...

  5. Development of the charge exchange recombination spectroscopy and the beam emission spectroscopy on the EAST tokamak.

    Science.gov (United States)

    Li, Y Y; Fu, J; Lyu, B; Du, X W; Li, C Y; Zhang, Y; Yin, X H; Yu, Y; Wang, Q P; von Hellermann, M; Shi, Y J; Ye, M Y; Wan, B N

    2014-11-01

    Charge eXchange Recombination Spectroscopy (CXRS) and Beam Emission Spectroscopy (BES) diagnostics based on a heating neutral beam have recently been installed on EAST to provide local measurements of ion temperature, velocity, and density. The system design features common light collection optics for CXRS and BES, background channels for the toroidal views, multi-chord viewing sightlines, and high throughput lens-based spectrometers with good signal to noise ratio for high time resolution measurements. Additionally, two spectrometers each has a tunable grating to observe any wavelength of interest are used for the CXRS and one utilizes a fixed-wavelength grating to achieve higher diffraction efficiency for the BES system. A real-time wavelength correction is implemented to achieve a high-accuracy wavelength calibration. Alignment and calibration are performed. Initial performance test results are presented. PMID:25430335

  6. Integrated analysis and consistency measurement of bremsstrahlung and charge exchange spectroscopy data for the determination of the ion effective charge

    International Nuclear Information System (INIS)

    In the context of Bayesian probability theory, we discuss a model for estimating the plasma ion effective charge Zeff, integrating data from both bremsstrahlung spectroscopy and individual impurity concentrations obtained via charge exchange spectroscopy (CXS). The validity of the model, taking into account statistical as well as systematic uncertainties, is shown via the deviance information criterion. The consistency of the continuum and CXS data regarding Zeff is improved, as measured by the symmetrized Kullback-Leibler divergence and the geodesic distance between the respective Zeff marginal posterior densities.

  7. Improved charge-coupled device detectors for high-speed, charge exchange spectroscopy studies on the DIII-D tokamak

    International Nuclear Information System (INIS)

    Charge exchange spectroscopy is one of the key ion diagnostics on the DIII-D tokamak. It allows determination of ion temperature, poloidal and toroidal velocity, impurity density, and radial electric field Er throughout the plasma. For the 2003 experimental campaign, we replaced the intensified photodiode array detectors on the central portion of the DIII-D charge exchange spectroscopy system with advanced charge-coupled device (CCD) detectors mounted on faster (f/4.7) Czerny-Turner spectrometers equipped with toroidal mirrors. The CCD detectors are improved versions of the ones installed on our edge system in 1999. The combination improved the photoelectron signal level by about a factor of 20 and the signal to noise by a factor of 2-8, depending on the absolute signal level. The new cameras also allow shorter minimum integration times while archiving to PC memory: 0.552 ms for the slower, lower-read noise (15 e) readout mode and 0.274 ms in the faster, higher-read noise (30 e) mode

  8. Wavelength calibration of the charge exchange recombination spectroscopy system on the DIII-D tokamak

    International Nuclear Information System (INIS)

    A wavelength calibration of all the detectors on the charge exchange recombination spectroscopy (CER) system is performed after every plasma discharge on the DIII-D tokamak. This is done to insure that the rest wavelength position of the C VI 5290.5 angstrom charge exchange line on the detector is accurately known so that the Doppler shift of the spectral line emitted during the discharge can be used for measurements of plasma rotation. In addition, this calibration provides a check on the spectral dispersion needed to determine the ion temperature. The reference spectra for the calibration are Ne I lines created by neon capillary discharge lamps contained within specially designed, diffuse reflectors. The Ne I lines at 3520.4720 angstrom, 5274.0393 angstrom, 5280.0853 angstrom, 5298.1891 angstrom, and 5304.7580 angstrom are used in this work. The location of these lines on the linear detectors can be determined to an accuracy of 0.1 pixel, which corresponds to a plasma rotation accuracy of 1.2 km/s and 0.7 km/s for the central and edge rotation measurements, respectively. Use of oppositely directed views of the plasma at the same major radius have been used to verify that the nominal 5290.5 angstrom wavelength of the C VI (n = 8 → 7) multiplet is the correct wavelength for the line emitted owing to charge exchange excitation

  9. High spatial and temporal resolution charge exchange recombination spectroscopy on the HL-2A tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Y. L.; Yu, D. L., E-mail: yudl@swip.ac.cn; Liu, L.; Cao, J. Y.; Sun, A. P.; Ma, Q.; Chen, W. J.; Liu, Yi; Yan, L. W.; Yang, Q. W.; Duan, X. R.; Liu, Yong [Southwestern Institute of Physics, Chengdu 610041 (China); Ida, K. [National Institute for Fusion Science, Toki 509-5292 (Japan); Hellermann, M. von [ITER Diagnostic Team, IO, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France); FOM-Institute for Plasma physics “Rijnhuizen,” Association EURATOM, Trilateral Euregio Cluster, 3430 BE Nieuwegein (Netherlands)

    2014-10-01

    A 32/64-channel charge exchange recombination spectroscopy (CXRS) diagnostic system is developed on the HL-2A tokamak (R = 1.65 m, a = 0.4 m), monitoring plasma ion temperature and toroidal rotation velocity simultaneously. A high throughput spectrometer (F/2.8) and a pitch-controlled fiber bundle enable the temporal resolution of the system up to 400 Hz. The observation geometry and an optimized optic system enable the highest radial resolution up to ~1 cm at the plasma edge. The CXRS system monitors the carbon line emission (C VI, n = 8–7, 529.06 nm) whose Doppler broadening and Doppler shift provide ion temperature and plasma rotation velocity during the neutral beam injection. The composite CX spectral data are analyzed by the atomic data and analysis structure charge exchange spectroscopy fitting (ADAS CXSFIT) code. First experimental results are shown for the case of HL-2A plasmas with sawtooth oscillations, electron cyclotron resonance heating, and edge transport barrier during the high-confinement mode (H-mode)

  10. High spatial and temporal resolution charge exchange recombination spectroscopy on the HL-2A tokamak

    International Nuclear Information System (INIS)

    A 32/64-channel charge exchange recombination spectroscopy (CXRS) diagnostic system is developed on the HL-2A tokamak (R = 1.65 m, a = 0.4 m), monitoring plasma ion temperature and toroidal rotation velocity simultaneously. A high throughput spectrometer (F/2.8) and a pitch-controlled fiber bundle enable the temporal resolution of the system up to 400 Hz. The observation geometry and an optimized optic system enable the highest radial resolution up to ∼1 cm at the plasma edge. The CXRS system monitors the carbon line emission (C VI, n = 8–7, 529.06 nm) whose Doppler broadening and Doppler shift provide ion temperature and plasma rotation velocity during the neutral beam injection. The composite CX spectral data are analyzed by the atomic data and analysis structure charge exchange spectroscopy fitting (ADAS CXSFIT) code. First experimental results are shown for the case of HL-2A plasmas with sawtooth oscillations, electron cyclotron resonance heating, and edge transport barrier during the high-confinement mode (H-mode)

  11. Design of charge exchange recombination spectroscopy for the joint Texas experimental tokamak.

    Science.gov (United States)

    Chi, Y; Zhuang, G; Cheng, Z F; Hou, S Y; Cheng, C; Li, Z; Wang, J R; Wang, Z J

    2014-11-01

    The old diagnostic neutral beam injector first operated at the University of Texas at Austin is ready for rejoining the joint Texas experimental tokamak (J-TEXT). A new set of high voltage power supplies has been equipped and there is no limitation for beam modulation or beam pulse duration henceforth. Based on the spectra of fully striped impurity ions induced by the diagnostic beam the design work for toroidal charge exchange recombination spectroscopy (CXRS) system is presented. The 529 nm carbon VI (n = 8 - 7 transition) line seems to be the best choice for ion temperature and plasma rotation measurements and the considered hardware is listed. The design work of the toroidal CXRS system is guided by essential simulation of expected spectral results under the J-TEXT tokamak operation conditions. PMID:25430328

  12. Measurement of ion temperature and toroidal rotation velocity using charge exchange recombination spectroscopy in Heliotron J

    International Nuclear Information System (INIS)

    This paper describes design and installation of a charge-exchange recombination spectroscopy (CXRS) system in Heliotron J. In this system, two tangential-heating neutral beams are used for plasma heating as well as the diagnostic beams. The sightlines are set to be parallel to the magnetic axis to achieve high spatial resolution. The spatial resolution is Δ ∼0.05 for a measurement area of 0.37 < r/a < 0.79. We adopted a Czerny-Turner monochromator, whose dispersion is 0.74 nm/mm. We applied this system is applied to an NBI plasma and the time evolution of the ion temperature and the toroidal rotation velocity profile are successfully obtained. (author)

  13. What can be Learned from X-ray Spectroscopy Concerning Hot Gas in Local Bubble and Charge Exchange Processes?

    Science.gov (United States)

    Snowden, Steve

    2007-01-01

    What can be learned from x-ray spectroscopy in observing hot gas in local bubble and charge exchange processes depends on spectral resolution, instrumental grasp, instrumental energy band, signal-to-nose, field of view, angular resolution and observatory location. Early attempts at x-ray spectroscopy include ROSAT; more recently, astronomers have used diffuse x-ray spectrometers, XMM Newton, sounding rocket calorimeters, and Suzaku. Future observations are expected with calorimeters on the Spectrum Roentgen Gamma mission, and the Solar Wind Charge Exchange (SWCX). The Geospheric SWCX may provide remote sensing of the solar wind and magnetosheath and remote observations of solar CMEs moving outward from the sun.

  14. Modification to poloidal charge exchange recombination spectroscopy measurement in JT-60U tokamak

    Institute of Scientific and Technical Information of China (English)

    Ding Bo-Jiang; Sakamoto Yoshiteru; Miura Yukitoshi

    2007-01-01

    With consideration of the effects of the atomic process and the sight line direction on the charge exchange recombination spectroscopy (CXRS), a code used to modify the poloidal CXRS measurement on Tokamak-60 Upgrade (JT-60U) in Japan Atomic Energy Research Institute is developed, offering an effective tool to modify the measurement and analyse experimental results further. The results show that the poloidal velocity of ion is overestimated but the ion temperature is underestimated by the poloidal CXRS measurement, and they also indicate that the effect of observation angle on rotation velocity is a dominant one in a core region (r/a< 0.65), whereas in an edge region where the sight line is nearly normal to the neutral beam, the observation angle effect is very small. The difference between the modified velocity and the neoclassical velocity is not larger than the error in measurement. The difference inside the internal transport barrier (ITB) region is 2-3 times larger than that outside the ITB region, and it increases when the effect of excited components in neutral beam is taken into account. The radial electric field profile is affected greatly by the poloidal rotation term, which possibly indicates the correlation between the poloidal rotation and the transport barrier formation.

  15. Charge exchange system

    Science.gov (United States)

    Anderson, Oscar A.

    1978-01-01

    An improved charge exchange system for substantially reducing pumping requirements of excess gas in a controlled thermonuclear reactor high energy neutral beam injector. The charge exchange system utilizes a jet-type blanket which acts simultaneously as the charge exchange medium and as a shield for reflecting excess gas.

  16. The deduction of low-Z ion temperature and densities in the JET tokamak using charge exchange recombination spectroscopy

    International Nuclear Information System (INIS)

    A charge exchange recombination spectroscopy (CXRS) diagnostic has been established on JET to study fully stripped low-Z species. Ion temperature in the plasma centre is measured from visible lines of helium, carbon and oxygen excited by charge exchange with heating neutral beam particles. Coincident cold components produced at the plasma edge are apparent on helium and carbon spectra and most spectra are subject to accidental blending from other species' edge plasma emission. The charge exchange feature can be isolated from the various composite lines and all three impurities agree on the same temperature within experimental error. Observed column emissivities are converted into absolute impurity densities using a neutral beam attenuation code and charge exchange effective rate coefficients. Comprehensive new calculations have been performed to obtain the effective rate coefficients. The models take detailed account of cascading and the influence of the plasma environment in causing l-mixing, and allow the n-dependence of the rate coefficients to be addressed experimentally. The effective ion charge reconstructed from simultaneous measurements of the densities of dominant impurities shows good agreement with the value inferred from visible Bremsstrahlung. Some illustrative results are shown for helium (helium discharge or minority r.f.. heating), carbon and oxygen concentrations monitored during characteristic operating regimes. (author)

  17. Development of the gas puff charge exchange recombination spectroscopy (GP-CXRS) technique for ion measurements in the plasma edge

    International Nuclear Information System (INIS)

    A novel charge-exchange recombination spectroscopy (CXRS) diagnostic method is presented, which uses a simple thermal gas puff for its donor neutral source, instead of the typical high-energy neutral beam. This diagnostic, named gas puff CXRS (GP-CXRS), is used to measure ion density, velocity, and temperature in the tokamak edge/pedestal region with excellent signal-background ratios, and has a number of advantages to conventional beam-based CXRS systems. Here we develop the physics basis for GP-CXRS, including the neutral transport, the charge-exchange process at low energies, and effects of energy-dependent rate coefficients on the measurements. The GP-CXRS hardware setup is described on two separate tokamaks, Alcator C-Mod and ASDEX Upgrade. Measured spectra and profiles are also presented. Profile comparisons of GP-CXRS and a beam based CXRS system show good agreement. Emphasis is given throughout to describing guiding principles for users interested in applying the GP-CXRS diagnostic technique

  18. What Can Be Learned from X-Ray Spectroscopy Concerning Hot Gas in the Local Bubble and Charge Exchange Processes?

    Science.gov (United States)

    Snowden, S. L.

    2008-01-01

    Both solar wind charge exchange emission and diffuse thermal emission from the Local Bubble are strongly dominated in the soft X-ray band by lines from highly ionized elements. While both processes share many of the same lines, the spectra should differ significantly due to the different production mechanisms, abundances, and ionization states. Despite their distinct spectral signatures, current and past observatories have lacked the spectral resolution to adequately distinguish between the two sources. High-resolution X-ray spectroscopy instrumentation proposed for future missions has the potential to answer fundamental questions such as whether there is any hot plasma in the Local Hot Bubble, and if so, what are the abundances of the emitting plasma and whether the plasma is in equilibrium. Such instrumentation will provide dynamic information about the solar wind including data on ion species which are currently difficult to track. It will also make possible remote sensing of the solar wind.

  19. Masking a CCD camera allows multichord charge exchange spectroscopy measurements at high speed on the DIII-D tokamak

    Science.gov (United States)

    Meyer, O.; Burrell, K. H.; Chavez, J. A.; Kaplan, D. H.; Chrystal, C.; Pablant, N. A.; Solomon, W. M.

    2011-02-01

    Charge exchange spectroscopy is one of the standard plasma diagnostic techniques used in tokamak research to determine ion temperature, rotation speed, particle density, and radial electric field. Configuring a charge coupled device (CCD) camera to serve as a detector in such a system requires a trade-off between the competing desires to detect light from as many independent spatial views as possible while still obtaining the best possible time resolution. High time resolution is essential, for example, for studying transient phenomena such as edge localized modes. By installing a mask in front of a camera with a 1024 × 1024 pixel CCD chip, we are able to acquire spectra from eight separate views while still achieving a minimum time resolution of 0.2 ms. The mask separates the light from the eight spectra, preventing spatial and temporal cross talk. A key part of the design was devising a compact translation stage which attaches to the front of the camera and allows adjustment of the position of the mask openings relative to the CCD surface. The stage is thin enough to fit into the restricted space between the CCD camera and the spectrometer endplate.

  20. Masking a CCD camera allows multichord charge exchange spectroscopy measurements at high speed on the DIII-D tokamak

    International Nuclear Information System (INIS)

    Charge exchange spectroscopy is one of the standard plasma diagnostic techniques used in tokamak research to determine ion temperature, rotation speed, particle density, and radial electric field. Configuring a charge coupled device (CCD) camera to serve as a detector in such a system requires a trade-off between the competing desires to detect light from as many independent spatial views as possible while still obtaining the best possible time resolution. High time resolution is essential, for example, for studying transient phenomena such as edge localized modes. By installing a mask in front of a camera with a 1024 x 1024 pixel CCD chip, we are able to acquire spectra from eight separate views while still achieving a minimum time resolution of 0.2 ms. The mask separates the light from the eight spectra, preventing spatial and temporal cross talk. A key part of the design was devising a compact translation stage which attaches to the front of the camera and allows adjustment of the position of the mask openings relative to the CCD surface. The stage is thin enough to fit into the restricted space between the CCD camera and the spectrometer endplate.

  1. Charge exchange spectroscopy of multiply charged ions for the development of the EUV light source for the next generation photo lithography

    Science.gov (United States)

    Tanuma, Hajime

    2015-09-01

    As a candidate of an extreme ultra-violet (EUV) light source for a next generation lithography, laser produced plasmas (LPP) of Xe and Sn have been investigated intensively in this decade because these plasmas have a strong emission around 13.5 nm which had been determined as the wavelength for the EUV lithography. This emission was considered to be due to multiply charged Xe and Sn ions in hot plasmas. However, the detail atomic spectroscopic data of these multiply charged heavy ions had not been reported yet. To provide atomic data for the understanding and development of the LPP as the EUV light source, we have observed the EUV emission spectra from individual charge states of Xe and Sn ions by means of a charge exchange spectroscopy method. Multiply charged Xeq+ (q = 7-23) and Snq+ (q = 5-21) ions were produced with a 14.25 GHz electron cyclotron resonance ion source, and a charge-selected ion beam was directed into a collision chamber, where the ion interact with a target gas of He and Xe. EUV emissions from the collision center were observed with a compact flat-field grazing-incident spectrometer equipped with a liquid nitrogen cooled CCD camera. In experiments using Xe ions, we have found only Xe XI has a strong UTA (unresolved transition array) around 13.5 nm. On the other hand, various charge states of Sn from VIII to XIV contribute to the 13.5 nm emission. Identification of the transition lines was carried out by calculations using the Hebrew university Livermore laboratory atomic physics code and the Cowan code. Most of the emissions in the EUV region are attributed to the 4p-4d and 4d- nl (nl = 4f, 5p, and 5f) transitions. However, the 4d-4f transitions have approximately constant differences of about 0.5 nm between the experimental and theoretical results. This can be explained by considering the strong configuration interactions in the n=4 subshells. Using the experimental transition wavelengths of multiply charged Sn ions, theoretical modeling of

  2. What can be Learned from X-Ray Spectroscopy Concerning Hot Gas in the Local Bubble and Charge Exchange Processes

    Science.gov (United States)

    Snowden, Steven L.

    2007-01-01

    Solar wind charge exchange produces diffuse X-ray emission with a variable surface brightness comparable to that of the cosmic background. While the temporal variation of the charge exchange emission allows some separation of the components, there remains a great deal of uncertainty as to the zero level of both. Because the production mechanisms of the two components are considerably different, their spectra would provide critical diagnostics to the understanding of both. However, current X-ray observatories are very limited in both spectral resolution and sensitivity in the critical soft X-ray (less than 1.0 keV) energy range. Non-dispersive high-resolution spectrometers, such as the calorimeter proposed for the Spectrum Roentgen Gamma mission, will be extremely useful in distinguishing the cascade emission of charge exchange from the spectra of thermal bremsstrahlung cosmic plasmas.

  3. Fast charge exchange spectroscopy using a Fabry-Perot spectrometer in the JIPP TII-U tokamak

    International Nuclear Information System (INIS)

    A new charge exchange spectroscopic technique using a Fabry-Perot spectrometer has been developed to increase the photon flux at the detector and improve the time resolution of ion temperature and plasma rotation velocity measurements. The spectral resolution is obtained by arranging two dimensional fiber optics and a two dimensional detector at the focal plane of a coupled lens located on both sides of a Fabry-Perot spectrometer. The effective finesse of the Fabry-Perot interferometer in this system is 14. The time evolution of the ion temperature is obtained with a time resolution of 125 μs and with the spatial resolution of 3 cm (8 channels). (author)

  4. A new diagnostic for ASDEX upgrade edge ion temperatures by lithium-beam charge exchange recombination spectroscopy

    International Nuclear Information System (INIS)

    This thesis work investigates the measurement of ion temperatures at the edge of a magnetically confined plasma used for fusion research at the ASDEX Upgrade tokamak operated by Max-Planck-Institut fuer Plasmaphysik in Garching. The H-mode plasma regime, default scenario of the next step experiment ITER, is characterized by an edge transport barrier, which is not yet fully explained by theory. Experimentally measured edge ion temperature profiles will help to test and develop models for these barriers. Transport theory on a basic level is introduced as background and motivation for the new diagnostic. The standard model for an edge plasma instability named ''edge localized mode'' (ELM) observed in H-mode is described. The implementation of a new diagnostic for ion temperature measurements with high spatial resolution in the plasma edge region, its commissioning and the validation of the measurements comprises the main part of this work. The emission of line radiation induced by charge exchange processes between lithium atoms injected by a beam source and fully ionized impurities (of C and He) is observed with a detection system consisting of spectrometers and fast cameras. Due to the narrow beam (1 cm) and closely staggered optical fibers (6 mm), unprecedented spatial resolution of edge ion temperatures in all major plasma regimes of the ASDEX Upgrade tokamak was achieved. The spectral width of the line radiation (He II at 468.5 nm and C VI at 529.0 nm) contains information about the local ion temperature from thermal Doppler-broadening, which is the dominant broadening mechanism for these lines. The charge-exchange contribution to the total line radiation locally generated by the lithium is determined by gating the beam. Fitting a Gaussian model function to the local line radiation results in absolute line widths which can be directly converted into a temperature. The equilibration of impurities with the main plasma is fast enough that the assumption of nearly

  5. Charge exchange emission from solar wind helium ions

    NARCIS (Netherlands)

    Bodewits, D; Hoekstra, R; Seredyuk, B; McCullough, RW; Jones, GH; Tielens, AGGM

    2006-01-01

    Charge exchange X-ray and far-ultraviolet (FUV) aurorae can provide detailed insight into the interaction between solar system plasmas. Using the two complementary experimental techniques of photon emission spectroscopy and translation energy spectroscopy, we have studied state-selective charge exch

  6. Fine structure of charge exchange lines observed in laboratory plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Ida, K.; Nishimura, S. [National Inst. for Fusion Science, Nagoya (Japan); Kondo, K.

    1997-01-01

    The influence of the fine structure of charge exchange lines appears only at the plasma edge or in the recombining phase where the ion temperature is low enough. The observed spectra in Li III and C VI are consistent with the sum of fine-structure components populated by statistical weights (assuming complete l-mixing) not by direct charge exchange cross sections. Some discrepancy was observed in the intensity ratio of fine-structure components between the observation and calculation for C VI in the recombining phase. The fine-structure of charge exchange lines gives an apparent Doppler shift in plasma rotation velocity measurement using charge exchange spectroscopy. (author)

  7. Production of antihydrogen via double charge exchange

    International Nuclear Information System (INIS)

    Spectroscopy of the 1S-2S transition of antihydrogen confined in a neutral atom trap and comparison with the equivalent spectral line in hydrogen will provide an accurate test of CPT symmetry and the first one in a mixed baryon-lepton system. Also, with neutral antihydrogen atoms, the gravitational interaction between matter and antimatter can be tested unperturbed by the much stronger Coulomb forces. Antihydrogen is regularly produced at CERN's Antiproton Decelerator by three-body-recombination (TBR) of one antiproton and two positrons. The method requires injecting antiprotons into a cloud of positrons, which raises the average temperature of the antihydrogen atoms produced way above the typical 0.5 K trap depths of neutral atom traps. Therefore only very few antihydrogen atoms can be confined at a time. Precision measurements, like laser spectroscopy, will greatly benefit from larger numbers of simultaneously trapped antihydrogen atoms. Therefore, the ATRAP collaboration developed a different production method that has the potential to create much larger numbers of cold, trappable antihydrogen atoms. Positrons and antiprotons are stored and cooled in a Penning trap in close proximity. Laser excited cesium atoms collide with the positrons, forming Rydberg positronium, a bound state of an electron and a positron. The positronium atoms are no longer confined by the electric potentials of the Penning trap and some drift into the neighboring cloud of antiprotons where, in a second charge exchange collision, they form antihydrogen. The antiprotons remain at rest during the entire process, so much larger numbers of trappable antihydrogen atoms can be produced. Laser excitation is necessary to increase the efficiency of the process since the cross sections for charge-exchange collisions scale with the fourth power of the principal quantum number n. This method, named double charge-exchange, was demonstrated by ATRAP in 2004. Since then, ATRAP constructed a new combined

  8. Charge-exchange straggling in equilibrium

    Energy Technology Data Exchange (ETDEWEB)

    Sigmund, P. [Department of Physics and Chemistry, University of Southern Denmark, DK-5230 Odense M (Denmark); Osmani, O. [Department of Physics, University of Duisburg-Essen, D-47048 Duisburg (Germany); Department of Physics, University of Kaiserslautern and Research Center OPTIMAS, D-67653 Kaiserslautern (Germany); Schinner, A. [Institut fuer Experimentalphysik, Johannes, Kepler Universitaet, A-4040 Linz (Austria)

    2011-05-01

    A general expression has been derived that allows computation of charge-exchange straggling of swift heavy ions when many charge states are involved. Charge exchange is found to hinge on the variation of the stopping cross section with the ion charge and on the transient behavior of the charge population as a function of traveled pathlength. These effects appear factorized in the final formula. The focus of this paper is on straggling in charge equilibrium. The case of MeV/u sulfur ions in carbon has been used as an illustration. Charge-exchange straggling is found to be dominating straggling over a considerable range of beam energies.

  9. Development of a laser cleaning method for the first mirror surface of the charge exchange recombination spectroscopy diagnostics on ITER

    International Nuclear Information System (INIS)

    A set of optical diagnostics is expected for measuring the plasma characteristics in ITER. Optical elements located inside discharge chambers are exposed to an intense radiation load, sputtering due to collisions with energetic atoms formed in the charge transfer processes, and contamination due to recondensation of materials sputtered from different parts of the construction of the chamber. Removing the films of the sputtered materials from the mirrors with the aid of pulsed laser radiation is an efficient cleaning method enabling recovery of the optical properties of the mirrors. In this work, we studied the efficiency of removal of metal oxide films by pulsed radiation of a fiber laser. Optimization of the laser cleaning conditions was carried out on samples representing metal substrates polished with optical quality with deposition of films on them imitating the chemical composition and conditions expected in ITER. It is shown that, by a proper selection of modes of radiation exposure to the surface with a deposited film, it is feasible to restore the original high reflection characteristics of optical elements

  10. Development of a laser cleaning method for the first mirror surface of the charge exchange recombination spectroscopy diagnostics on ITER

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, A. P., E-mail: APKuznetsov@mephi.ru [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation); Buzinskij, O. I. [State Research Center Troitsk Institute for Innovation and Fusion Research (TRINITI) (Russian Federation); Gubsky, K. L.; Nikitina, E. A.; Savchenkov, A. V.; Tarasov, B. A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation); Tugarinov, S. N. [State Research Center Troitsk Institute for Innovation and Fusion Research (TRINITI) (Russian Federation)

    2015-12-15

    A set of optical diagnostics is expected for measuring the plasma characteristics in ITER. Optical elements located inside discharge chambers are exposed to an intense radiation load, sputtering due to collisions with energetic atoms formed in the charge transfer processes, and contamination due to recondensation of materials sputtered from different parts of the construction of the chamber. Removing the films of the sputtered materials from the mirrors with the aid of pulsed laser radiation is an efficient cleaning method enabling recovery of the optical properties of the mirrors. In this work, we studied the efficiency of removal of metal oxide films by pulsed radiation of a fiber laser. Optimization of the laser cleaning conditions was carried out on samples representing metal substrates polished with optical quality with deposition of films on them imitating the chemical composition and conditions expected in ITER. It is shown that, by a proper selection of modes of radiation exposure to the surface with a deposited film, it is feasible to restore the original high reflection characteristics of optical elements.

  11. Spectroscopy with trapped highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P

    2008-01-23

    We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed, and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

  12. Profile Measurement of Ion Temperature and Toroidal Rotation Velocity with Charge Exchange Recombination Spectroscopy Diagnostics in the HL-2A Tokamak

    Institute of Scientific and Technical Information of China (English)

    吴静; 姚列明; 朱建华; 韩晓玉; 李文柱

    2012-01-01

    This paper deals with the profile measurement of impurity ion temperature and toroidal rotation velocity that can be achieved by using the charge exchange recombination spectrum (CXRS) diagnostics tool built on the HL-2A toknmak. By using CXRS, an accurate impurity ion temperature and toroidal plasma rotation velocity profile can be achieved under the condition of neutrM beam injection (NBI) heating. Considering the edge effect of the line of CVI 529.06 nm (n= 8-7), which contains three lines (active exciting spectral line (ACX), passivity exciting spectral line (PCX) and electron exciting spectral line (ICE)), and using three Gaussian fitted curves, we obtain the following experimental results: the core ion temperature of HL-2A device is nearly thousands of eV, and the plasma rotation velocity reaches about 104 m· s^-1. At the end of paper, some explanations are presented for the relationship between the curves and the inner physical mechanism.

  13. Pion double charge exchange and nuclear structure

    International Nuclear Information System (INIS)

    Pion double charge exchange to both the double-analog state and the ground state is studied for medium weight nuclei. The relative cross section of these two transitions and the importance of nuclear structure as a function of pion kinetic energy is examined. 16 figs., 5 tabs

  14. Charge exchange recombination spectroscopy measurements in the extreme ultraviolet region of central carbon concentrations during high power neutral beam heating in TFTR [Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    The carbon concentration in the central region of TFTR discharges with high power neutral beam heating has been measured by charge-extracted recombination spectroscopy (CXRS) of the C+5 n = 3--4 transition in the extreme ultraviolet region. The carbon concentrations were deduced from absolute measurements of the line brightness using a calculation of the beam attenuation and the appropriate cascade-corrected line excitation rates. As a result of the high ion temperatures in most of the discharges, the contribution of beam halo neutrals to the line brightness was significant and therefore had to be included in the modeling of the data. Carbon concentrations have been measured in discharges with Ip = 1.0-1.6 MA and beam power in the range of 2.6-30 MW, including a number of supershots. The results are in good agreement with carbon concentrations deduced from the visible bremsstrahlung Zeff and metallic impurity concentrations measured by x-ray pulse-height analysis, demonstrating the reliability of the atomic rates used in the beam attenuation and line excitation calculations. Carbon is the dominant impurity species in these discharges; the oxygen concentration measured via CXRS in a high beam power case was 0.0006 of ne, compard to 0.04 for carbon. Trends with Ip and beam power in the carbon concentration and the inferred deuteron concentration are presented. The carbon concentration is independent of Ip and decreases from 0.13 at 2.6 MW beam power to 0.04 at 30 MW, while the deuteron concentration increases from 0.25 to 0.75 over the same range of beam power. These changes are primarily the result of beam particle fueling, as the carbon density did not vary significantly with beam power. The time evolutions of the carbon and deuteron concentrations during two high power beam pulses, one which exhibited a carbon bloom and one which did not, are compared. 30 refs., 12 figs., 2 tabs

  15. Charge exchange in solar wind - coometary interactions

    International Nuclear Information System (INIS)

    The authors examine the effect of charge exchange between fast solar wind ions and slow cometary neutrals at the contact discontinuity separating the ionosphere of a comet from the solar wind flow. The continuity equations were solved analytically for a water-dominated cometary ionosphere, including both ionization and recombination processes. It was found that this new solution differs significantly from the one obtained by neglecting recombination. (author)

  16. Dissociative charge exchange of H2+

    International Nuclear Information System (INIS)

    This thesis is devoted to molecular dissociation, in particular the dissociation of the hydrogen molecule H2 arising from electron capture of its ion H2+ in a collision. Thereby the important practical question how a chemical bond can be broken is implicitly addressed. This thesis opens (chapter I) with an overview of the available experimental approaches in molecular physics. Further the simple Demkov model for NRCE is described. In chapter II a novel experimental technique for measurements on dissociative processes is introduced which combines a high efficiency with a high energy resolution. A detailed description of the techniques applied in the detector, which has a high spatial and timing resolution with 30 μm and 350 psec FWHM respectively for the detection of one particle, is given in chapter III. A semi-classical theory for NRCE in the medium energy range between a diatomic molecular ion and an atom is developed in chapter IV. The experiments on dissociative charge exchange of H2+ with Ar, Mg, Na and Cs targets at keV energies are described in Chapter V. The predissociation of the c3PIsub(u)-state of H2 populated after charge exchange of H2 with several targets at keV energies; is the subject of chapter VI. In chapter VII, orientational oscillations in the cross section for charge exchange of H2+ with alkali targets are discussed. The last chapter deals with predissociation of highly excited states in H2. (Auth.)

  17. Anatomy of charge-exchange straggling

    International Nuclear Information System (INIS)

    We have studied charge-exchange straggling theoretically for swift krypton and silicon ions and five target gases in the MeV/u energy regime. We find a pronounced two-peak structure for all ion-target combinations. The peak at the highest energy appears around the velocity where the bare ion and the one-electron ion are equally abundant in the equilibrium charge distribution. Correspondingly, the low-energy peak appears near the cross-over between the charge fractions of the two- and the three-electron ion. The possibility of further peaks at lower energies is discussed. Our findings are compared with recent experimental results on straggling of krypton beams

  18. Anatomy of charge-exchange straggling

    Energy Technology Data Exchange (ETDEWEB)

    Sigmund, P., E-mail: sigmund@sdu.dk [Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M (Denmark); Osmani, O. [Department of Physics, University of Duisburg-Essen, D-47048 Duisburg (Germany); Schinner, A. [Institut für Experimentalphysik, Johannes Kepler Universität, A-4040 Linz (Austria)

    2014-11-01

    We have studied charge-exchange straggling theoretically for swift krypton and silicon ions and five target gases in the MeV/u energy regime. We find a pronounced two-peak structure for all ion-target combinations. The peak at the highest energy appears around the velocity where the bare ion and the one-electron ion are equally abundant in the equilibrium charge distribution. Correspondingly, the low-energy peak appears near the cross-over between the charge fractions of the two- and the three-electron ion. The possibility of further peaks at lower energies is discussed. Our findings are compared with recent experimental results on straggling of krypton beams.

  19. Carbon charge exchange analysis in the ITER-like wall environment

    International Nuclear Information System (INIS)

    Charge exchange spectroscopy has long been a key diagnostic tool for fusion plasmas and is well developed in devices with Carbon Plasma-Facing Components. Operation with the ITER-like wall at JET has resulted in changes to the spectrum in the region of the Carbon charge exchange line at 529.06 nm and demonstrates the need to revise the core charge exchange analysis for this line. An investigation has been made of this spectral region in different plasma conditions and the revised description of the spectral lines to be included in the analysis is presented

  20. Charge exchange recombination x-ray laser

    International Nuclear Information System (INIS)

    A recombining plasma x-ray laser using charge exchange recombination (CXR) is proposed. Fully stripped carbon ions collide with neutral He atoms and become excited hydrogenlike carbon ions, in which the excited levels with n=3 or 4 are mainly populated. We calculate the gain coefficients of the Balmer α and the Lyman β line of the hydrogenlike carbon ions by the use of a collisional-radiative model in which the CXR process is included. The calculated result shows that substantial gain can be generated for the Lyman β and Balmer α lines and that the gain of the Balmer α line can be strongly enhanced by the effect of CXR. We also report a preliminary experiment of this scheme. (author)

  1. Systematics of pion double charge exchange

    International Nuclear Information System (INIS)

    Differential cross sections have been measured for pion-induced double-charge-exchange (DCX) reactions leading to double-isobaric-analog states (DIAS) and low-lying nonanalog states in the residual nuclei. A description of the experimental details and data analysis is presented. The experimentally observed systematics of reactions leading to DIAS, to nonanalog ground states, and to low-lying 2+ states are described. Lowest-order optical-model calculations of DIAS DCX are compared to the data. Efforts to understand the anomalies by invoking additional reaction-mechanism amplitudes and a higher-order optical potential are described. Calculations of nonanalog DCX reactions leading to J/sup π/ = 0+ states were performed within a distorted-wave impulse-approximation framework. The sensitivities of these calculations to input parameters are discussed. 58 refs., 41 figs., 16 tabs

  2. Multistep processes in charge-exchange reactions

    CERN Document Server

    Demetriou, P; Marianski, B

    2002-01-01

    Cross sections for the charge-exchange sup 6 sup 5 Cu(p, n) sup 6 sup 5 Zn reaction at the incident energy of 27 MeV and the sup 1 sup 0 sup 0 Mo(p, n) sup 1 sup 0 sup 0 Tc reaction at the incident energy of 26 MeV have been calculated using the multistep direct reaction theory of Feshbach, Kerman and Koonin. The theory was modified to include the non-DWBA matrix elements and the isovector collective vibrations according to the prescription of Marcinkowski and Marianski. The results show enhanced contributions from two-, three- and four-step direct reactions in agreement with experiment.

  3. Suzaku Observations of Charge Exchange Emission from Solar System Objects

    Science.gov (United States)

    Ezoe, Y.; Fujimoto, R.; Yamasaki, N. Y.; Mitsuda, K.; Ohashi, T.; Ishikawa, K.; Oishi, S.; Miyoshi, Y; Terada, N.; Futaana, Y.; Porter, F. S.; Brown, G. V.

    2012-01-01

    Recent results of charge exchange emission from solar system objects observed with the Japanese Suzaku satellite are reviewed. Suzaku is of great importance to investigate diffuse X-ray emission like the charge exchange from planetary exospheres and comets. The Suzaku studies of Earth's exosphere, Martian exosphere, Jupiter's aurorae, and comets are overviewed.

  4. A purely classical description of crossings of energy levels and spectroscopic signatures of charge exchange

    International Nuclear Information System (INIS)

    Charge exchange and crossings of corresponding energy levels that enhance charge exchange are strongly connected with problems of energy loss and diagnostics in high-temperature plasmas. Charge exchange has also been proposed as one of the most effective mechanisms for population inversion in the soft x-ray and VUV ranges. One area of the most fundamental theoretical importance in the study of charge exchange is the problem of electron terms in the field of two stationary Coulomb centres (TCC) of charges Z and Z' separated by a distance R. This involves fascinating atomic physics: the terms can have crossings and quasicrossings. These rich features of the TCC problem are also manifest in other areas of physics such as plasma spectroscopy: a quasicrossing of the TCC terms, by enhancing charge exchange, can result in an unusual structure (a dip) in the spectral line profile emitted by a Z-ion from a plasma consisting of both Z- and Z'-ions, as has been shown theoretically and experimentally. The paradigm is that these sophisticated features of the TCC problem and their flourishing applications are inherently quantum phenomena. In this paper we disprove this paradigm. We present a purely classical description of both the crossings of energy levels in the TCC problem and the dips in the corresponding spectral line profiles caused by the crossing (via enhanced charge exchange). Our classical description is based on first principles and does not use any model assumptions. (author)

  5. X-ray emission from charge exchange of highly-charged ions in atoms and molecules

    Science.gov (United States)

    Greenwood, J. B.; Williams, I. D.; Smith, S. J.; Chutjian, A.

    2000-01-01

    Charge exchange followed by radiative stabilization are the main processes responsible for the recent observations of X-ray emission from comets in their approach to the Sun. A new apparatus was constructed to measure, in collisions of HCIs with atoms and molecules, (a) absolute cross sections for single and multiple charge exchange, and (b) normalized X-ray emission cross sections.

  6. Proceedings of the LAMPF workshop on pion double charge exchange

    International Nuclear Information System (INIS)

    Experimental and theoretical aspects of double-analog, nonanalog, and continuum pion double charge exchange in the 50- to 310-MeV energy range are covered. Separate abstracts were prepared for 22 papers in these proceedings

  7. Charge exchange between singly ionized helium ions

    International Nuclear Information System (INIS)

    The plane-wave Born approximation was used to evaluate the charge transfer cross sections for the reaction He+ + He+ → He++ + He. The charge transfer cross section is graphed as a function of incident energy and compared with experimental measurements

  8. Nuclear spectroscopy on charge density wave systems

    International Nuclear Information System (INIS)

    This book is the first coherent presentation of investigations of charge density wave (CDW) systems by nuclear spectroscopic techniques. It is addressed to the graduate students and elder scientist who are interested in modern aspects of solid state physics and want to acquire a broader knowledge of nuclear spectroscopy techniques applied to CDW systems. Chapter 1 gives a short introduction to CDW's in general and to the question what can be learned about CDW's by nuclear spectroscopy techniques. Chapter 2 gives a Landau theory description of CDW formation in chain-like tetrachalcogenides. Chapter 3 treats experimental results on layered transition metal compounds. A short introduction to nuclear magnetic resonance (NMR), nuclear quadrupole resonance (NQR), time differential perturbed angular correlation (TDPAC), and the Moessbauer effect (ME) is included in this chapter because all three techniques have been extensively applied to Ta-dichalcogenides which are prominent members of this family of materials. Chapter 4 and 5 treat in great detail CDW dynamics and transport in chain-like like transition metal chalcogenides and molybdenum bronzes, respectively. Chapter 6 treats the one-dimensional inorganic complex salt K-2Pt(CN)4Br0.3.2H2O (KCP) studied by NMR on a variety of nuclei. Chapter 7 demonstrates the tremendous advances of high resolution NMR in yielding spin density maps of organic radical salts and is intended to stimulate the application of this powerful technique more directly to CDW phenomena

  9. Ion momentum and energy transfer rates for charge exchange collisions

    Science.gov (United States)

    Horwitz, J.; Banks, P. M.

    1973-01-01

    The rates of momentum and energy transfer have been obtained for charge exchange collisions between ion and neutral gases having arbitrary Maxwellian temperatures and bulk transport velocities. The results are directly applicable to the F-region of the ionosphere where 0+ - 0 charge is the dominant mechanism affecting ion momentum and energy transfer.

  10. Impurity charge-exchange processes in Tokamak plasmas

    International Nuclear Information System (INIS)

    Charge-exchange reactions between multiply-charged impurity ions and neutral hydrogen isotopes are considered. Ionization equilibrium and radiative losses are evaluated for oxygen and iron in the presence of either 'thermal' or 'beam' neutrals. The influence of 'thermal' neutrals on recently reported results from ohmically heated TFR discharges is also discussed

  11. Probing nuclear correlations with pion-nucleus double charge exchange

    International Nuclear Information System (INIS)

    In this paper we have calculated the lowest order pion double charge reaction mechanism using shell model wavefunctions of medium weight nuclei. We have the sequential reaction mechanism in which the pion undergoes two single-charge exchange scatterings on the valence neutrons. The distortion of the incoming, intermediate, and outgoing pion are included. The closure approximation is made for the intermediate states with an average excitation energy used in the pion propagator. The double-charge exchange is assumed to take place on the valence nucleons which are assumed to be in one spherical shell model orbital. 34 refs., 5 figs., 3 tabs

  12. Charge exchange of a polar molecule at its cation

    International Nuclear Information System (INIS)

    The Landau-Herring method is used to derive an analytic expression for the one-electron exchange interaction of a polar molecule with its positively charged ion, induced by a σ-electron. Analogously to the classical Van der Pole method, the exchange interaction potential is averaged over the rotational states of colliding particles. The resonant charge-transfer cross section is calculated, and the effect of the dipole moments of the core on the cross section is analyzed. It is shown that allowance for the dependence of the exchange potential on the orientation of the dipole moments relative to the molecular axis may change the dependence of the cross section on the velocity of colliding particles, which is typical of the resonant charge exchange, from the resonance to the quasi-resonance dependence.

  13. Charge exchange X-rays from the heliosheath

    Science.gov (United States)

    Medvedev, M. V.; Robertson, I. P.; Cravens, T. E.; Zank, G. P.; Florinski, V.

    2006-09-01

    X-rays are produced throughout the heliosphere as a consequence of charge transfer collisions between heavy solar wind ions and neutral atoms. After such a collision the solar wind ion is left in a highly excited state and emits extreme ultraviolet and soft X-ray photons. In the outer heliosphere, solar wind charge exchange X-ray emission is mainly due to charge exchange with neutral interstellar hydrogen. We have combined MHD simulations with a comprehensive charge exchange computation code. We trace the full evolution of solar wind ions along stream line in order to produce three-dimensional emissivities and, subsequently, two-dimensional X-ray brightness and spectral maps of the heliosphere as would be observed from the outside. The model treats both the collisionally thin and the collisionally thick regimes. This model can be a diagnostic tool for studying stellar wind properties of nearby Sun-like stars.

  14. Fluctuation spectroscopy in organic charge transfer salts

    International Nuclear Information System (INIS)

    Quasi-twodimensional organic charge-transfer salts show certain analogies to the High-Temperature Cuprate Superconductors (HTSC), e.g., the layered structure where conducting and insulating sheets do alternate as well as the direct proximity of the antiferromagnetic insulating ground state to the superconducting phase. At higher temperatures the formation of a pseudo-gap in the density of states is discussed also. In contrast to the HTSC the electronic properties of the organic charge-transfer salts can be easily influenced by external parameters such as hydrostatic or chemical pressure - in a generalized phase diagram the usage of different anions X can be mapped on the axis W/U as well, see Sec. 4.2 - or moderate temperatures. In the quasi-twodimensional K-(BEDT-TTF)2X salts, e.g., a moderate pressure of p ∝ 250 bar is sufficient to shift the antiferromagnetic-insulating system (X=Cu[N(CN)2]Cl) to the metallic side of the phase diagram showing even superconductivity below a critical temperature of Tc ∝ 12.8 K. Doping as in the HTSC and the undesirable disorder accompanied with it is not necessary to induce a metal-to-insulator transition. Therefore the experimental requirements are more easily met in this class of materials compared to other strongly correlated electron systems. All this makes the organic charge-transfer salts ideal model systems to study fundamental concepts of theoretical solid state physics some of which have been of academical interest only so far. In this work fluctuation spectroscopy has been used for the first time to investigate the low-frequency dynamics of the TT-electron system in the quasi-twodimensional organic charge-transfer salts K-(BEDT-TTF)2X with the aim to gain information about the temperature, pressure and magnetic field dependence of the power spectral density of the resistance noise and therefore about the dynamics of the charge carrier fluctuations. Especially in the vicinity of correlation driven ordering phenomena

  15. Study of nuclei' excitation in the charge exchange reactions (Draft)

    International Nuclear Information System (INIS)

    Carried out experimental and theoretical studies show, that in the nuclear charge exchange reactions there is an unique ability for study both properties and behavior of the delta-isobar in the excited nuclear environment. However for theoretical analysis of these reactions it is necessary have experimental data on nuclei charge exchange on free nucleons. It is offered the experiment of measurement dependence of inclusive cross section of the tritium nuclei charge exchange in 3He nuclei on hydrogen from transferred energy. This reaction is isotopically dependent on 3He nuclei in tritons charge exchange reaction on neutrons. Aim of proposed experiment is checking of a hypothesis believability about the delta-isobar excitation in flying nucleus, and measurement of the process intensity. Peculiarity of this experiment is application of relativistic tritons beams formed from accelerated fragments of 4He nuclei. Experimental facility presents of combination of two one-arm spectrometers: first one - time-flying spectrometer for measurement tritium nuclei impulse in beam to target with accuracy 0.3 % for 6 GeV/s and identification of tritium nuclei, the second one - magnetic spectrometer for identification and measurement of 3He nuclei impulse forming in the result of the charge exchange reaction

  16. Deuteron charge radius from spectroscopy data in atomic deuterium

    CERN Document Server

    Pohl, Randolf; Udem, Thomas; Antognini, Aldo; Beyer, Axel; Fleurbaey, Hélène; Grinin, Alexey; Hänsch, Theodor W; Julien, Lucile; Kottmann, Franz; Krauth, Julian J; Maisenbacher, Lothar; Matveev, Arthur; Biraben, François

    2016-01-01

    We give a pedagogical description of the method to extract the charge radii and Rydberg constant from laser spectroscopy in regular hydrogen (H) and deuterium (D) atoms, that is part of the CODATA least-squares adjustment of the fundamental physical constants. We give a deuteron charge radius from D spectroscopy alone of 2.1415(45) fm. This value is independent of the proton charge radius, and five times more accurate than the value found in the CODATA Adjustment 10.

  17. A charge exchange chamber with built-in focusing

    International Nuclear Information System (INIS)

    This invention concerns a charge exchange chamber with built-in focusing enabling a beam of low divergence neutrals to be obtained from a beam of ions of a given energy. The ion beam enters the charge exchange chamber filled with a neutral gas under pressure, the effect of which is an exchange of charges between the ions and the neutral molecules or atoms of the gas. The positive ions are substantially sent along the axis of the enclosure, characterised in that it includes electric facilities for concentrating the ions of the beam near this axis. These electric facilities are composed of a series of grids perpendicular to the direction of the ion jet, grids that are transparent and of negative potential and the potential of each of these grids increases in absolute value along the path of the ion jet in the enclosure

  18. Charge-exchange giant resonances as probes of nuclear structure

    International Nuclear Information System (INIS)

    Giant resonances populated in charge-exchange reactions can reveal detailed information about nuclear structure properties, in spite of their apparent featurelessness. The (p,n) and (n,p) reactions - as well as their analog reactions - proceed via the same nuclear matrix element as beta decay. Thereby, they are useful for probing electroweak properties in nuclei, especially for those not accessible to beta decay. The nuclear physics aspects of double beta decay might be investigated in double charge-exchange reactions. detailed nuclear structure information, such as the presence of ground-state correlations, can be revealed via identification of 'first-forbidden' transitions. In addition, astrophysics aspects and halo properties of nuclei have been investigated in charge exchange. Finally, these experiments have questioned our knowledge of the absolute strength of the strong interaction

  19. Charge-exchange giant resonances as probes of nuclear structure

    Energy Technology Data Exchange (ETDEWEB)

    Blomgren, J. [Uppsala Univ., (Sweden). Dept. of Neutron Research

    2001-09-01

    Giant resonances populated in charge-exchange reactions can reveal detailed information about nuclear structure properties, in spite of their apparent featurelessness. The (p,n) and (n,p) reactions - as well as their analog reactions - proceed via the same nuclear matrix element as beta decay. Thereby, they are useful for probing electroweak properties in nuclei, especially for those not accessible to beta decay. The nuclear physics aspects of double beta decay might be investigated in double charge-exchange reactions. detailed nuclear structure information, such as the presence of ground-state correlations, can be revealed via identification of 'first-forbidden' transitions. In addition, astrophysics aspects and halo properties of nuclei have been investigated in charge exchange. Finally, these experiments have questioned our knowledge of the absolute strength of the strong interaction.

  20. Charge Exchange Spectra of Hydrogenic and He-like Iron

    CERN Document Server

    Wargelin, B J; Neill, P A; Olson, R E; Scofield, J H

    2005-01-01

    We present H-like Fe XXVI and He-like Fe XXV charge-exchange spectra resulting from collisions of highly charged iron with N2 gas at an energy of 10 eV/amu in an electron beam ion trap. Although individual high-n emission lines are not resolved in our measurements, we observe that the most likely level for Fe25+ --> Fe24+ electron capture is n~9, in line with expectations, while the most likely value for Fe26+ --> Fe25+ charge exchange is significantly higher. In the Fe XXV spectrum, the K-alpha emission feature dominates, whether produced via charge exchange or collisional excitation. The K-alpha centroid is lower in energy for the former case than the latter (6666 versus 6685 eV, respectively), as expected because of the strong enhancement of emission from the forbidden and intercombination lines, relative to the resonance line, in charge-exchange spectra. In contrast, the Fe XXVI high-n Lyman lines have a summed intensity greater than that of Ly-alpha, and are substantially stronger than predicted from the...

  1. Spectroscopic signatures of avoided crossings caused by charge exchange in plasmas

    International Nuclear Information System (INIS)

    Electron terms in the field of two stationary Coulomb centres (TCCs) of charges Z and Z' separated by a distance R are a fundamental problem of quantum mechanics, presenting fascinating atomic physics: the terms show crossings and avoided crossings. In the latter situation, the electron has a much larger probability of tunnelling from one well to the other (i.e. of charge exchange) than in the absence of such degeneracy. These rich features of the TCC problem are also manifest in different areas of physics such as plasma spectroscopy. Recently it was shown experimentally that charge exchange, enhanced by the encounter of two TCC terms, can result in an unusual structure (a dip) in the spectral line profile emitted by a Z ion from a plasma consisting of both Z and Z' ions. In this paper we present a detailed quantitative theory of this phenomenon, in which its origin is directly traced to the avoided crossings of terms in the TCC problem. We show that our theory explains quantitatively all the results of the above experiment where such a dip was observed in a hydrogen line. We also consider in detail several prospective 'radiator-perturber' pairs for observing these signatures of charge exchange in lines of hydrogen-like ions. Further experimental studies of such dips would serve to produce not-yet-available fundamental data on charge exchange between multicharged ions, virtually inaccessible by other experimental methods. (author)

  2. Measurement of absorption and charge exchange of $\\pi^+$ on carbon

    CERN Document Server

    Ieki, K; Berkman, S; Bhadra, S; Cao, C; de Perio, P; Hayato, Y; Ikeda, M; Kanazawa, Y; Kim, J; Kitching, P; Mahn, K; Nakaya, T; Nicholson, M; Olchanski, K; Rettie, S; Tanaka, H A; Wilking, M J; Tobayama, S; Yamauchi, T; Yen, S; Yokoyama, M

    2015-01-01

    The combined cross section for absorption and charge exchange interactions of positively charged pions with carbon nuclei for the momentum range 200 MeV/c to 300 MeV/c have been measured with the DUET experiment at TRIUMF. The uncertainty is reduced by nearly half compared to previous experiments. This result will be a valuable input to existing models to constrain pion interactions with nuclei.

  3. Charge exchange cooling in the tandem mirror plasma confinement apparatus

    International Nuclear Information System (INIS)

    A method and apparatus are described for cooling a plasma confined in the center mirror cell of the tandem mirror apparatus by injecting cold neutral species of the plasma into at least one mirroring region of the center mirror cell. The cooling is due to the loss of warm charged species through charge exchange with the cold neutral species with resulting diffusion of the warm neutral species out of the plasma

  4. Charge exchange between hydrogen atoms and fully stripped heavy ions

    International Nuclear Information System (INIS)

    Charge exchange between multicharged ions and background atomic and molecular gases represents one of the limitations to the attainment of high charge states in heavy ion sources, particularly containment sources. An attempt is made to study systematically a particularly simple but in many respects representative class of such reactions, namely charge transfer between atomic hydrogen and fully stripped heavy ions. Approximate cross sections for these processes in the low keV range of collision energies were obtained using a multistate Landau--Zener method. The energy and Z dependences of the cross sections are discussed

  5. Charge exchange and chemical reactions with trapped Th3+

    International Nuclear Information System (INIS)

    We have measured the reaction rates of trapped, buffer gas cooled Th3+ and various gases and have analyzed the reaction products using trapped ion mass spectrometry techniques. Ion trap lifetimes are usually limited by reactions with background molecules, and the high electron affinity of multiply charged ions such as Th3+ make them more prone to loss. Our results show that reactions of Th3+ with carbon dioxide, methane, and oxygen all occur near the classical Langevin rate, while reaction rates with argon, hydrogen, and nitrogen are orders of magnitude lower. Reactions of Th3+ with oxygen and methane proceed primarily via charge exchange, while simultaneous charge exchange and chemical reaction occurs between Th3+ and carbon dioxide. Loss rates of Th3+ in helium are consistent with reaction with impurities in the gas. Reaction rates of Th3+ with nitrogen and argon depend on the internal electronic configuration of the Th3+.

  6. Charge Exchange and Chemical Reactions with Trapped Th$^{3+}$

    CERN Document Server

    Churchill, L R; Chapman, M S

    2010-01-01

    We have measured the reaction rates of trapped, buffer gas cooled Th$^{3+}$ and various gases and have analyzed the reaction products using trapped ion mass spectrometry techniques. Ion trap lifetimes are usually limited by reactions with background molecules, and the high electron affinity of multiply charged ions such as Th$^{3+}$ make them more prone to loss. Our results show that reactions of Th$^{3+}$ with carbon dioxide, methane, and oxygen all occur near the classical Langevin rate, while reaction rates with argon, hydrogen, and nitrogen are orders of magnitude lower. Reactions of Th$^{3+}$ with oxygen and methane proceed primarily via charge exchange, while simultaneous charge exchange and chemical reaction occurs between Th$^{3+}$ and carbon dioxide. Loss rates of Th$^{3+}$ in helium are consistent with reaction with impurities in the gas. Reaction rates of Th$^{3+}$ with nitrogen and argon depend on the internal electronic configuration of the Th$^{3+}$.

  7. Automatic analysis of JET charge exchange spectra using neural networks

    International Nuclear Information System (INIS)

    The analysis of charge exchange recombination spectra represents a very challenging problem due to the presence of many overlapping spectral lines. Conventional approaches are based on iterative least-squares optimization and suffer from the two difficulties of low speed and the need for a good initial approximation to the solution. This latter problem necessitates considerable human supervision of the analysis procedure. It is shown how neural network techniques allow charge exchange data to be analysed very rapidly, to give an approximate solution without the need for supervision. The network approach is well suited to the fast intershot analysis of large volumes of data, and can readily be implemented in dedicated hardware for real-time applications. The neural network can also be used to provide the initial guess for the standard least-squares algorithm when high accuracy is required. (Author)

  8. Pion charge-exchange reactions: The analog state transitions

    International Nuclear Information System (INIS)

    The general features of pion charge-exchange reactions leading to nuclear-isobaric-analog states (IAS) and double-isobaric-analog states (DIAS), as they have emerged from studies over the past ten years, are reviewed. The energy range investigated is 20 to 550 MeV for IAS transitions and 20 to 300 MeV for DIAS transitions. These data are seen to play an important role in characterizing the pion optical potential, in determining the Δ-N interaction in nuclei, and in the study of nucleon correlations in nuclei. Recent progress achieved in understanding the role of such correlations in double-charge-exchange reactions is reviewed. 55 refs., 43 figs., 3 tabs

  9. Microscopic optical potentials - study of charge-exchange reactions

    International Nuclear Information System (INIS)

    The present thesis is engaged in two different aspects of direct nuclear reactions, namely on the one hand in the microscopic calculation of the imaginary optical potential for the elastic alpha-nucleus scattering as well on the other hand in the microscopic analysis of giant resonance states which are excited by (p,n) and (n,p) charge-exchange reactions. In the first part in the framework of the nuclear structure approximation to the optical potential a microscopic calculation of the imaginary part of the optical potential for α40Ca scattering at Esub(α) = 31 and 100 MeV is performed. In the second part the 208Pb(p,n) and 208Pb(n,p) charge-exchange reactions are studied at low ( E 100 MeV) incident energies. (orig./HS)

  10. Improved pellet charge exchange measurements in Large Helical Device

    International Nuclear Information System (INIS)

    The pellet charge exchange technique (PCX), which is a combination of the compact neutral particle analyzer and an impurity pellet, is a unique method to observe the radial energetic particle distribution. There are not only charge exchange reactions between the hydrogen in the pellet and a proton, but also between the partially ionized carbon in the pellet and the proton. The neutralization factor from energetic ion to neutral particle could be deduced from the electron temperature and the electron density of the pellet cloud. The radial profiles of energetic particle distribution were measured and compared in various ion cyclotron resonance heating (ICH) plasmas. The energetic particle flux significantly increased at the resonance layer created by the ICH. PCX provides more precise information about the resonance layer than conventional neutral particle diagnostics. (author)

  11. Charge-exchange measurements of fully-stripped oxygen and carbon ion radial density profiles in TFR

    International Nuclear Information System (INIS)

    Fully-ionized oxygen and carbon ions have been detected in TFR via charge-exchange recombination spectroscopy using a modulated auxiliary neutral beam, thus allowing their radial density profiles to be obtained. An impurity transport numerical code is then used to deduce the impurity transport parameters

  12. Experimental determination of rate coefficients of charge exchange from x-dips in laser-produced plasmas

    Czech Academy of Sciences Publication Activity Database

    Dalimier, E.; Oks, E.; Renner, Oldřich; Schott, R.

    2007-01-01

    Roč. 40, - (2007), s. 909-919. ISSN 0953-4075 R&D Projects: GA MŠk(CZ) LC528 Institutional research plan: CEZ:AV0Z10100523 Keywords : laser-produced plasma * x-ray emission * high-resolution spectroscopy * charge exchange phenomena Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.012, year: 2007

  13. Elastic scattering and charge exchange reactions with exotic beams

    International Nuclear Information System (INIS)

    The elastic scattering of 6He, 10,11Be secondary beams on a (CH2)3 target and the charge exchange reaction p(6He,6Li)n have been measured. Very good agreement was found for the 6He+12C data with a four-body eikonal scattering model. A microscopic optical potential was used to reproduce the proton-nucleus elastic scattering data. (author)

  14. Elastic and charge exchange scattering of pions from 3He

    International Nuclear Information System (INIS)

    Elastic and charge exchange scatterings of pions from 3He are studied using on optical potential in the momentum representation, which includes the second order effect as well as the nucleon binding correction. These corrections are found to be appreaciable but still not enough to resolve the discrepancy between theoretical calculations and recent experimental data on the reaction 3He(π-, π0)3H. (author)

  15. μ+ charge exchange and muonium formation in low pressure gases

    International Nuclear Information System (INIS)

    Using the basic muon spin rotation technique, the fractions of energetic positive muons thermalizing in diamagnetic environments (fsub(μ)) or as the paramagnetic muonium atom (fsub(Mu)) have been measured in low pressure pure gases (He, Ne, Ar, Kr, Xe, H2, N2, NH3, and CH4) as well as in several gas mixtures (Ne/Xe, Ne/Ar, Ne/NH3, Ne/CH4). In the pure gases, the muonium fractions fsub(Mu) are generally found to be smaller than expected from analogous proton charge exchange studies, particularly in the molecular gases. This is probably due to hot atom reactions of muonium following the charge exchange regime. Comparisons with monium formation in condensed matter as well as positronium formation in gases are also presented. In the gas mixtures, the addition of only a few hundred ppm of a dopant gas, which is exothermic for muonium formation (e.g. Xe), gives rise to an fsub(Mu) characteristic of the pure dopant gas itself, demonstrating the importance of the neutralization process right down to thermal energies. In all cases, the experimental signal amplitudes are found to be strongly pressure dependent, which is interpreted in terms of the time spent by the muon as neutral muonium in the charge exchange regime: tsub(n) < 0.2 ns. This time is generally shorter in the case of molecular gases than in rare gases

  16. Solar System X-rays from Charge Exchange Processes

    Science.gov (United States)

    Lisse, Carey M.; Christian, D. J.; Bhardwaj, A.; Dennerl, K.; Wolk, S. J.; Bodewits, D.; Combi, M. R.; Zurbuchen, T. H.; Lepri, S. T.

    2013-04-01

    The discovery of high energy x-ray emission in 1996 from comet C/1996 B2 (Hyakutake) uncovered a new class of x-ray emitting objects. Subsequent detections of the morphology, spectra, and time dependence of the x-rays from more than 20 comets have shown that the very soft (E charge-exchange interaction between highly charged solar wind minor ions and the comet's extended neutral atmosphere. Many solar system objects are now known to shine in the X-ray, including Venus, Mars, the Moon, the Earth, Jupiter, and Saturn, with total power outputs on the MW - GW scale. Like comets, the X-ray emission from the Earth's geo-corona, the Jovian & Saturnian aurorae, and the Martian halo are thought to be driven by charge exchange between highly charged minor (heavy) ions in the solar wind and gaseous neutral species in the bodies' atmosphere. The non-auroral X-ray emissions from Jupiter, Saturn, and Earth, and those from disks of Mars, Venus, and the Moon are produced by scattering of solar X-rays. The first soft X-ray observations of Earth’s aurora by Chandra shows that it is highly variable, and the giant planet aurorae are fascinating puzzles that are just beginning to yield their secrets and may be the only x-ray sources not driven directly by the Sun in the whole system as well as properties of hot exo-solar Jupiters. Observations of local solar system charge exchange processes can also help inform us about x-rays produced at more distant hot ionized gas/cold neutral gas interfaces, like the heliopause, stellar astrospheres, galactic star forming regions, and starburst galaxies.

  17. Charge exchange in fluid description of partially ionized plasmas

    CERN Document Server

    Vranjes, J; Luna, M

    2015-01-01

    The effects of charge exchange on waves propagating in weakly ionized plasmas are discussed. It is shown that for low-frequency processes, ions and neutrals should be treated as a single fluid with some effective charge on all of them. We have derived a new momentum equation which should be used in such an environment. As a result, the low-frequency magnetic waves can propagate even if particles are not magnetized, which is entirely due to the charge exchange and the fact that it is not possible to separate particles into two different populations as charged and neutral species. So there can be no friction force between ions and neutrals in the usual sense. The mean force per particle is proportional to the ionization ratio $n_i/(n_i+ n_n)$. Regarding the application of the theory to the Alfven wave propagation in the lower solar atmosphere, the results predict that the plane of displacement of the fluid must change by 90 degrees when an Alfven wave propagates from the area where particles are un-magnetized (...

  18. Estimation of Charge Exchange Recombination Emission Based on Diagnostic Neutral Beam on the Experimental Advanced Superconducting Tokamak

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xian-Mei; WAN Bao-Nian; WU Zhen-Wei

    2007-01-01

    Diagnostic neutral beam (DNB) attenuation and charge exchange recombination emission are estimated on EAST tokamak. Approximately 40% of the beam with the energy of 50 keV can reach the plasma centre (r = 0) for the typical parameters of the Experimental Advanced Superconducting Tokamak (EAST) plasma. Emissivities of CVI (n = 8 → 7, 529.0nm) and OVⅢ (n = 10 → 9, 607.0 nm) visible charge exchange recombination emissions based on the DNB are estimated. The emissivities of the visible bremsstrahlung emission near this wavelength are also calculated for comparison. The results show that the charge exchange recombination emission is about two orders of magnitude greater than the bremsstrahlung emission. It is theoretically indicated that the ratio of signal of charge exchange recombination spectroscopy to the noise from background bremsstrahlung emission,S/N, is large enough in the EAST tokamak with the typical designed parameters. The present results are helpful for experiment design of charge-exchange recombination spectroscopy based on the DNB in the EAST tokamak.

  19. High resolution probe of coherence in low-energy charge exchange collisions with oriented targets

    OpenAIRE

    Leredde, A.; Fléchard, X.; Cassimi, A.; Hennecart, D.; Pons, B.

    2013-01-01

    The trapping lasers of a magneto-optical trap (MOT) are used to bring Rb atoms into well defined oriented states. Coupled to recoil-ion momentum spectroscopy (RIMS), this yields a unique MOTRIMS setup which is able to probe scattering dynamics, including their coherence features, with unprecedented resolution. This technique is applied to the low-energy charge exchange processes Na$^+$+Rb($5p_{\\pm 1}$) $\\rightarrow$ Na($3p,4s$)+Rb$^+$. The measurements reveal detailed features of the collisio...

  20. High resolution probe of coherence in low-energy charge exchange collisions with oriented targets

    CERN Document Server

    Leredde, A; Cassimi, A; Hennecart, D; Pons, B

    2013-01-01

    The trapping lasers of a magneto-optical trap (MOT) are used to bring Rb atoms into well defined oriented states. Coupled to recoil-ion momentum spectroscopy (RIMS), this yields a unique MOTRIMS setup which is able to probe scattering dynamics, including their coherence features, with unprecedented resolution. This technique is applied to the low-energy charge exchange processes Na$^+$+Rb($5p_{\\pm 1}$) $\\rightarrow$ Na($3p,4s$)+Rb$^+$. The measurements reveal detailed features of the collisional interaction which are employed to improve the theoretical description. All of this enables to gauge the reliability of intuitive pictures predicting the most likely capture transitions.

  1. X-ray spectroscopic study of charge exchange phenomena in plasma-wall interaction

    Czech Academy of Sciences Publication Activity Database

    Renner, Oldřich; Krouský, Eduard; Šmíd, Michal; Liska, R.; Váchal, P.; Khattak, F.Y.; Dalimier, E.; Oks, E.

    Les Ulis Cedex A : E D P SCIENCES, 2013, s. 14005. ISBN 9782759810772. ISSN 2100-014X. - (EPJ Web of Conferences. vol. 59). [International Conference on Inertial Fusion Sciences and Applications /7./ - IFSA 2011. Bordeaux (FR), 12.09.2011-16.09.2011] R&D Projects: GA ČR GAP205/10/0814; GA MŠk(CZ) LC528 Institutional support: RVO:68378271 Keywords : laser-produced plasmas * X-ray spectroscopy * plasma jets * charge exchange * plasma smulation Subject RIV: BL - Plasma and Gas Discharge Physics

  2. Configuration interaction in charge exchange spectra of tin and xenon

    International Nuclear Information System (INIS)

    Charge-state-specific extreme ultraviolet spectra from both tin ions and xenon ions have been recorded at Tokyo Metropolitan University. The electron cyclotron resonance source spectra were produced from charge exchange collisions between the ions and rare gas target atoms. To identify unknown spectral lines of tin and xenon, atomic structure calculations were performed for Sn14+-Sn17+ and Xe16+-Xe20+ using the Hartree-Fock configuration interaction code of Cowan (1981 The Theory of Atomic Structure and Spectra (Berkeley, CA: University of California Press)). The energies of the capture states involved in the single-electron process that occurs in these slow collisions were estimated using the classical over-barrier model.

  3. Charge distribution in neptunium compounds calculated from moessbauer spectroscopy data

    International Nuclear Information System (INIS)

    Calculations of the 5f-orbitals population density in the neptunium compounds are carried out on the basis of experimental data, obtained by the Moessbauer spectroscopy method. Charge distribution in compounds Np(3), Np(4), Np(5), Np(6) and Np(7) is presented. Approach to studying the correlation between the δ indices and orbital population densities is proposed

  4. Laser-Assisted H- Charge Exchange Injection in Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Gorlov, Timofey V [ORNL; Danilov, Viatcheslav V [ORNL; Shishlo, Andrei P [ORNL

    2010-01-01

    The use of stripping foils for charge exchange injection can cause a number of operational problems in high intensity hadron accelerators. A recently proposed three-step method of laser-assisted injection is capable of overcoming these problems. This paper presents advances in the physical model of laser-assisted charge exchange injection of H- beams and covers a wide field of atomic physics. The model allows the calculation of the evolution of an H0 beam taking into account spontaneous emission, field ionization and external electromagnetic fields. Some new data on the hydrogen atom related to the problem are calculated. The numerical calculations in the model use realistic descriptions of laser field and injection beam. Generally, the model can be used for design and optimization of a laser-assisted injection cell within an accelerator lattice. Example calculations of laser-assisted injection for an intermediate experiment at SNS in Oak Ridge and for the PS2 accelerator at CERN are presented. Two different schemes, distinctively characterized by various magnetic fields at the excitation point, are discussed. It was shown that the emittance growth of an injected beam can be drastically decreased by moving excitation point into a strong magnetic field.

  5. Laser-assisted H- charge exchange injection in magnetic fields

    Science.gov (United States)

    Gorlov, T.; Danilov, V.; Shishlo, A.

    2010-05-01

    The use of stripping foils for charge exchange injection can cause a number of operational problems in high intensity hadron accelerators. A recently proposed three-step method of laser-assisted injection is capable of overcoming these problems. This paper presents advances in the physical model of laser-assisted charge exchange injection of H- beams and covers a wide field of atomic physics. The model allows the calculation of the evolution of an H0 beam taking into account spontaneous emission, field ionization, and external electromagnetic fields. Some new data on the hydrogen atom related to the problem are calculated. The numerical calculations in the model use realistic descriptions of laser field and injection beam. Generally, the model can be used for design and optimization of a laser-assisted injection cell within an accelerator lattice. Example calculations of laser-assisted injection for an intermediate experiment at SNS in Oak Ridge and for the PS2 accelerator at CERN are presented. Two different schemes, distinctively characterized by various magnetic fields at the excitation point, are discussed. It was shown that the emittance growth of an injected beam can be drastically decreased by moving the excitation point into a strong magnetic field.

  6. Nucleon charge-exchange reactions at intermediate energy

    Energy Technology Data Exchange (ETDEWEB)

    Alford, W.P. [Western Ontario Univ., London, ON (Canada). Dept. of Physics]|[TRIUMF, Vancouver, BC (Canada); Spicer, B.M. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    An historical review of the development of ideas pertaining to Gamow-Teller giant resonances is given, and a description of the emergence of techniques for the study of charge exchange reactions - particularly the technical advances which yielded the recent volume of new date. The present status of charge exchange reactions is reviewed and assessed. Evidence is presented from the {sup 14}C(p,n) reaction for the dominance of the spin-isospin component of the nucleon-nucleon interaction in intermediate energy reactions. In (p,n) reactions the Gamow-Teller giant resonance dominates the spectra, with higher multipoles contributing. By contrast, in (n,p) reactions in the heavier nuclei, the Gamow-Teller transitions are substantially Pauli-blocked and the spin dipole resonance dominates, with contributions from higher multipoles. Discussions of the multipole decomposition process, used to obtain from the data the contributions of the different multipoles, and the contributions of the multipoles, are given. 226 refs., 19 figs.

  7. Analysis of JET charge exchange spectra using neural networks

    International Nuclear Information System (INIS)

    Active charge exchange spectra representing the local interaction of injected neutral beams and fully stripped impurity ions are hard to analyse due to strong blending with passive emission from the plasma edge. As a result, the deduced plasma parameters (e.g. ion temperature, rotation velocity, impurity density) cannot always be determined unambiguously. Also, the speed of the analysis is limited by the time consuming nonlinear least-squares minimization procedure. In practice, semi-manual analysis is necessary and fast, automatic analysis, based on currently used techniques, does not seem feasible. In this paper the development of a robust and accurate analysis procedure based on multi-layer perceptron (MLP) neural networks is described. This procedure is fully automatic and fast, thus enabling a real-time analysis of charge exchange spectra. Accuracy has been increased in several ways as compared to earlier straightforward neural network implementations and is comparable to a standard least-squares based analysis. Robustness is achieved by using a combination of different confidence measures. A novel technique for the creation of training data, suitable for high-dimensional inverse problems has been developed and used extensively. A new method for fast calculation of error bars directly from the hidden neurons in a MLP network is also described, and used as part of the confidence calculations. For demonstration purposes, a real-time ion temperature profile diagnostic based on this work has been implemented. (author)

  8. Analysis of JET charge exchange spectra using neural networks

    International Nuclear Information System (INIS)

    Active charge exchange spectra representing the local interaction of injected neutral beams and fully stripped impurity ions are hard to analyse due to the strong blending with passive emission from the plasma edge. As a result, the deduced plasma parameters (e.g. ion temperature, rotation velocity, impurity density) can not always be determined unambiguously. Also, the speed of the analysis is limited by the time consuming non-linear least-squares minimisation procedure. In practice, semi-manual analysis is necessary, and fast, automatic analysis, based on currently used techniques, does not seem feasible. In this paper the development of a robust and accurate analysis procedure based on Multi Layer Perception (MLP) neural networks is described. This procedure is fully automatic and fast, thus enabling a real-time analysis of charge exchange spectra. Accuracy has been increased in several ways as compared to earlier straight-forward neural network implementations and is comparable to a standard least squares based analysis. Robustness is achieved by using a combination of different confidence measures. A novel technique for the creation of training data, suitable for high dimensional inverse problems has been developed, and used extensively. A new method for fast calculation of error bars directly from the hidden neurons in a MLP network is also described, and used as part of the confidence calculations. For demonstration purposes, a real-time ion temperature profile diagnostic based on this has been implemented. (author)

  9. Charge exchange produced K-shell x-ray emission from Ar16+ in a tokamak plasma with neutral beam injection

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P; Bitter, M; Marion, M; Olson, R E

    2004-12-27

    High-resolution spectroscopy of hot tokamak plasma seeded with argon ions and interacting with an energetic, short-pulse neutral hydrogen beam was used to obtain the first high-resolution K-shell x-ray spectrum formed solely by charge exchange. The observed K-shell emission of Ar{sup 16+} is dominated by the intercombination and forbidden lines, providing clear signatures of charge exchange. Results from an ab initio atomic cascade model provide excellent agreement, validating a semiclassical approach for calculating charge exchange cross sections.

  10. High resolution charge spectroscopy of heavy ions with FNTD technology

    Science.gov (United States)

    Bartz, J. A.; Kodaira, S.; Kurano, M.; Yasuda, N.; Akselrod, M. S.

    2014-09-01

    This paper is focused on the improvement of the heavy charge particle charge resolution of Fluorescent Nuclear Track Detector (FNTD) technology. Fluorescent intensity of individual heavy charge particle tracks is used to construct the spectrum. Sources of spectroscopic line broadening were investigated and several fluorescent intensity correction procedures were introduced to improve the charge resolution down to δZ = 0.25 c.u. and enable FNTD technology to distinguish between all projectile fragments of 290 MeV carbon ions. The benefits of using FNTD technology for fragmentation study include large dynamic range and wide angular acceptance. While we describe these developments in the context of fragmentation studies, the same techniques are readily extended to FNTD LET spectroscopy in general.

  11. Charge-state dynamics in electrostatic force spectroscopy

    Science.gov (United States)

    Ondráček, Martin; Hapala, Prokop; Jelínek, Pavel

    2016-07-01

    We present a numerical model that allows us to study the response of an oscillating probe in electrostatic force spectroscopy to charge switching in quantum dots at various time scales. The model provides more insight into the behavior of frequency shift and dissipated energy under different scanning conditions when measuring a temporarily charged quantum dot on a surface. Namely, we analyze the dependence of the frequency shift, the dissipated energy, and their fluctuations on the resonance frequency of the tip and on the electron tunneling rates across the tip–quantum dot and quantum dot–sample junctions. We discuss two complementary approaches to simulating the charge dynamics, a stochastic and a deterministic one. In addition, we derive analytic formulas valid for small amplitudes, describing relations between the frequency shift, dissipated energy, and the characteristic rates driving the charging and discharging processes.

  12. Ultrafast Charge Transfer Visualized by Two-Dimensional Electronic Spectroscopy

    Directory of Open Access Journals (Sweden)

    Mančal T.

    2013-03-01

    Full Text Available Two-dimensional electronic spectroscopy (2D-ES is used to investigate ultrafast excited-state dynamics in a lutetium bisphthalocyanine dimer. Following optical excitation, a chain of electron and hole transfer steps gives rise to characteristic cross-peak dynamics in the electronic 2D spectra. The combination of density matrix propagation and quantum chemical calculations results in a molecular view of the charge transfer dynamics and highlights the role of the counter-ion in providing an energetic perturbation which promotes charge transfer across the complex.

  13. Charged-particle spectroscopy in organic semiconducting single crystals

    Science.gov (United States)

    Ciavatti, A.; Sellin, P. J.; Basiricò, L.; Fraleoni-Morgera, A.; Fraboni, B.

    2016-04-01

    The use of organic materials as radiation detectors has grown, due to the easy processability in liquid phase at room temperature and the possibility to cover large areas by means of low cost deposition techniques. Direct charged-particle detectors based on solution-grown Organic Semiconducting Single Crystals (OSSCs) are shown to be capable to detect charged particles in pulse mode, with very good peak discrimination. The direct charged-particle detection in OSSCs has been assessed both in the planar and in the vertical axes, and a digital pulse processing algorithm has been used to perform pulse height spectroscopy and to study the charge collection efficiency as a function of the applied bias voltage. Taking advantage of the charge spectroscopy and the good peak discrimination of pulse height spectra, an Hecht-like behavior of OSSCs radiation detectors is demonstrated. It has been possible to estimate the mobility-lifetime value in organic materials, a fundamental parameter for the characterization of radiation detectors, whose results are equal to μτcoplanar = (5 .5 ± 0.6 ) × 10-6 cm2/V and μτsandwich = (1 .9 ± 0.2 ) × 10-6 cm2/V, values comparable to those of polycrystalline inorganic detectors. Moreover, alpha particles Time-of-Flight experiments have been carried out to estimate the drift mobility value. The results reported here indicate how charged-particle detectors based on OSSCs possess a great potential as low-cost, large area, solid-state direct detectors operating at room temperature. More interestingly, the good detection efficiency and peak discrimination observed for charged-particle detection in organic materials (hydrogen-rich molecules) are encouraging for their further exploitation in the detection of thermal and high-energy neutrons.

  14. Ultrafast Charge Transfer Visualized by Two-Dimensional Electronic Spectroscopy

    OpenAIRE

    Mančal T.; Milota F.; Hauer J; Christensson N.; Bixner O.; Lukeš V.; Kauffmann H. F.

    2013-01-01

    Two-dimensional electronic spectroscopy (2D-ES) is used to investigate ultrafast excited-state dynamics in a lutetium bisphthalocyanine dimer. Following optical excitation, a chain of electron and hole transfer steps gives rise to characteristic cross-peak dynamics in the electronic 2D spectra. The combination of density matrix propagation and quantum chemical calculations results in a molecular view of the charge transfer dynamics and highlights the role of the counter-ion in providing an en...

  15. Charge exchange measurements of ion behavior in the ISX tokamak

    International Nuclear Information System (INIS)

    Analysis of charge exchange neutrals is the standard method for measuring ion behavior in tokamak plasmas. Limitations of this technique, which arise in dense and neutral-beam-heated plasmas, are discussed. Two refinements that address these limitations are described: a neutral particle analyzer, which incorporates both mass and energy resolution to distinguish different ion components such as the fast and thermal ions in beam-heated plasmas, and an improved data analysis procedure, which accounts for the effects of profiles and neutral attenuation in dense plasmas. A simple two-dimensional Monte Carlo neutral transport code was developed and used to investigate the effects of toroidally asymmetric neutral density profiles. Applications of these methods to experiments in the Impurity Study Experiment (ISX) are discussed; they include energy confinement studies on ISX-A, natural beam heating and high beta studies on ISX-B, and pellet fueling studies on ISX-B

  16. Delta excitation in nuclei: the lesson of charge exchange reactions

    International Nuclear Information System (INIS)

    We present an attempt of theoretical interpretation of charge exchange reactions on nuclei in the region of the delta resonance. Special care is taken to insure consistency with the constraints from pion and photon excitation channels. Good agreement with measured spectra can be obtained for all types of targets and incident ions except for polarized deuterons data which appear hardly reconcilable with the others within our interpretation. Despite the peripheral character of these reactions, a sizeable part of the observed downward shift of the resonance is possibly ascribable to a yet undetected collective mode of the nucleus at high excitation, the pionic branch. Our limited commitment is due to uncomplete knowledge of the NN → N Δ interaction and the transition form factors of the probing ions which has been palliated by some phenomenology

  17. Charge Exchange Losses and Stochastic Acceleration in the Solar Wind

    CERN Document Server

    Kenny, Ciaran

    2016-01-01

    Stochastic acceleration of particles under a pressure balance condition can accommodate the universal $p^{-5}$ spectra observed under many different conditions in the inner heliosphere. In this model, in order to avoid an infinite build up of particle pressure, a relationship between the momentum diffusion of particles and the adiabatic deceleration in the solar wind must exist. This constrains both the spatial and momentum diffusion coefficients and results in the $p^{-5}$ spectrum in the presence of adiabatic losses in the solar wind. However, this theory cannot explain the presence of such spectra beyond the termination shock, where adiabatic deceleration is negligible. To explain this apparent discrepancy, we include the effect of charge exchange losses, resulting in new forms of both the spatial and momentum diffusion coefficients that have not previously been considered. Assuming that the turbulence is of a large-scale compressible nature, we find that a balance between momentum diffusion and losses can...

  18. Coherent pion production in heavy ion charge exchange reactions

    International Nuclear Information System (INIS)

    We report the first observation of coherent pion production induced by a heavy ion charge exchange reaction. The (12C,12N) reaction [D. Bachelier et al., Phys. Lett. B 172 (1986) 23; M. Roy-Stephan et al., Nucl. Phys. A 488 (1988) 178] at 1.1 GeV/nucleon has been used to shine negative (off-shell) pions on nuclei and observe (on-shell) pions, leaving the target nucleus in its ground state. The experiment was performed at the Laboratoire National Saturne with the SPES4-π setup [Laurent Farhi PHD thesis IPNO-T97-12, Universite d'Orsay, 1997; Rasmus Dahl Ph.D., Niels Bohr Institutet, Copenhagen (1999)

  19. Deuteron-proton charge exchange reaction at small transfer momentum

    CERN Document Server

    Ladygina, N B

    2004-01-01

    The charge-exchange reaction pd -> npp at 1 GeV projectile proton energy is studied. This reaction is considered in a special kinematics, when the transfer momentum from the beam proton to fast outgoing neutron is close to zero. Our approach is based on the Alt-Grassberger-Sandhas formulation of the multiple-scattering theory for the three-nucleon system. The matrix inversion method has been applied to take account of the final state interaction (FSI) contributions. The differential cross section, tensor analyzing power $C_{0,yy}$, vector-vector $C_{y,y}$ and vector-tensor $C_{y,xz}$ spin correlation parameters of the initial particles are presented. It is shown, that the FSI effects play a very important role under such kinematical conditions. The high sensitivity of the considered observables to the elementary nucleon-nucleon amplitudes has been obtained.

  20. Resonance charge exchange between excited states in slow proton-hydrogen collisions

    International Nuclear Information System (INIS)

    The theory of resonance charge exchange in slow collisions of a proton with a hydrogen atom in the excited state is developed. It extends the Firsov-Demkov theory of resonance charge exchange to the case of degenerate initial and final states. The theory is illustrated by semiclassical and quantum calculations of charge exchange cross sections between states with n=2 in parabolic and spherical coordinates. The results are compared with existing close-coupling calculations.

  1. High resolution charge spectroscopy of heavy ions with FNTD technology

    International Nuclear Information System (INIS)

    Highlights: •FNTD technology was utilized to obtain charge spectra of carbon-ion fragments. •Several correction techniques were developed to minimize line broadening. •Charge resolution of 0.25 c.u. was demonstrated. •Light fragments starting from hydrogen and helium were detected. -- Abstract: This paper is focused on the improvement of the heavy charge particle charge resolution of Fluorescent Nuclear Track Detector (FNTD) technology. Fluorescent intensity of individual heavy charge particle tracks is used to construct the spectrum. Sources of spectroscopic line broadening were investigated and several fluorescent intensity correction procedures were introduced to improve the charge resolution down to δZ = 0.25 c.u. and enable FNTD technology to distinguish between all projectile fragments of 290 MeV carbon ions. The benefits of using FNTD technology for fragmentation study include large dynamic range and wide angular acceptance. While we describe these developments in the context of fragmentation studies, the same techniques are readily extended to FNTD LET spectroscopy in general

  2. Cyclic voltammetry on sputter-deposited films of electrochromic Ni oxide : Power-law decay of the charge density exchange

    OpenAIRE

    Wen, Rui-Tao; Granqvist, Claes G.; Niklasson, Gunnar A.

    2014-01-01

    Ni-oxide-based thin films were produced by reactive direct-current magnetron sputtering and were characterized by X-ray diffraction and Rutherford backscattering spectroscopy. Intercalation of Li+ ions was accomplished by cyclic voltammetry (CV) in an electrolyte of LiClO4 in propylene carbonate, and electrochromism was documented by spectrophotometry. The charge density exchange, and hence the optical modulation span, decayed gradually upon repeated cycling. This phenomenon was accurately de...

  3. Solar Wind Charge Exchange Studies Of Highly Charged Ions On Atomic Hydrogen

    International Nuclear Information System (INIS)

    Accurate studies of low-energy charge exchange (CX) are critical to understanding underlying soft X-ray radiation processes in the interaction of highly charged ions from the solar wind with the neutral atoms and molecules in the heliosphere, cometary comas, planetary atmospheres, interstellar winds, etc.. Particularly important are the CX cross sections for bare, H-like, and He-like ions of C, N, O and Ne, which are the dominant charge states for these heavier elements in the solar wind. Absolute total cross sections for single electron capture by H-like ions of C, N, O and fully-stripped O ions from atomic hydrogen have been measured in an expanded range of relative collision energies (5 eV/u-20 keV/u) and compared to previous H-oven measurements. The present measurements are performed using a merged-beams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source installed on a high voltage platform at the Oak Ridge National Laboratory. For the collision energy range of 0.3 keV/u-3.3 keV/u, which corresponds to typical ion velocities in the solar wind, the new measurements are in good agreement with previous H-oven measurements. The experimental results are discussed in detail and compared with theoretical calculations where available.

  4. Plasma code for astrophysical charge exchange emission at X-ray wavelengths

    CERN Document Server

    Gu, Liyi; Raassen, A J J

    2016-01-01

    Charge exchange X-ray emission provides unique insights into the interactions between cold and hot astrophysical plasmas. Besides its own profound science, this emission is also technically crucial to all observations in the X-ray band, since charge exchange with the solar wind often contributes a significant foreground component that contaminates the signal of interest. By approximating the cross sections resolved to $n$ and $l$ atomic subshells, and carrying out complete radiative cascade calculation, we create a new spectral code to evaluate the charge exchange emission in the X-ray band. Comparing to collisional thermal emission, charge exchange radiation exhibits enhanced lines from large-$n$ shells to the ground, as well as large forbidden-to-resonance ratios of triplet transitions. Our new model successfully reproduces an observed high-quality spectrum of comet C/2000 WM1 (LINEAR), which emits purely by charge exchange between solar wind ions and cometary neutrals. It demonstrates that a proper charge ...

  5. Charge-exchange reaction by Reggeon exchange and W{sup +}W{sup −}-fusion

    Energy Technology Data Exchange (ETDEWEB)

    Schicker, R. [Phys. Inst., University Heidelberg (Germany)

    2015-04-10

    Charge-exchange reactions at high energies are examined. The existing cross section data on the Reggeon induced reaction pp → n + Δ{sup ++} taken at the ZGS and ISR accelerators are extrapolated to the energies of the RHIC and LHC colliders. The interest in the charge-exchange reaction induced by W{sup ±}-fusion is presented, and the corresponding QCD-background is examined.

  6. Characteristics of solid-target charge-exchange analyzers for energetic ion diagnostics on tokamaks

    International Nuclear Information System (INIS)

    Compact electrostatic charge-exchange analyzers have been constructed for installation in areas of high magnetic fields and restricted access near tokamak fusion devices. The analyzers employed carbon stripping foils, and have been calibrated for proton energies between 1 and 70 keV. They have been successfully used to study charge-exchange losses in auxiliary-heated tokamak plasmas

  7. Zero dead time spectroscopy without full charge collection

    International Nuclear Information System (INIS)

    The Savannah River Technology Center has built a remote gamma monitoring instrument which employs data sampling techniques rather than full charge collection to perform energy spectroscopy without instrument dead time. The raw, unamplified anode output of a photomultiplier tube is directly coupled to the instrument to generate many digital samples during the charge collection process, so that all pulse processing is done in the digital domain. The primary components are a free running, 32 MSPS, 10-bit A/D, a field programmable gate array, FIFO buffers, and a digital signal processor (DSP). Algorithms for pulse integration, pile-up rejection, and other shape-based criteria are being developed in DSP code for migration into the gate array. Spectra taken with a 2 in NaI(Tl) detector have been obtained at rates as high as 59 000 counts per second without dead time with peak resolution at 662 keV measuring 7.3%

  8. Nuclear isovector giant resonances excited by pion single charge exchange

    International Nuclear Information System (INIS)

    This thesis is an experimental study of isovector giant resonances in light nuclei excited by pion single charge exchange reactions. Giant dipole resonances in light nuclei are known to be highly structured. For the mass 9 and 13 giant dipole resonances, isospin considerations were found to be very important to understanding this structure. by comparing the excitation functions from cross section measurements of the (π+, π0) and (π, π0) inclusive reactions, the authors determined the dominant isospin structure of the analog IVGR's. The comparison was made after decomposing the cross section into resonant and non-resonant components. This decomposition is made in the framework of strong absorption and quasi-free scattering. Measurements in the region of the isovector giant dipole resonances (IVGDR) were made to cover the inclusive angular distributions out to the second minimum. Study of the giant resonance decay process provides further understanding of the resonances. This study was carried out by observing the (π+, π0p) coincident reactions involving the resonances of 9B and 13N excited from 9Be and 13C nuclei. These measurements determined the spectra of the decay protons. This method also permitted a decomposition of the giant resonances into their isospin components. The multipolarities of the resonances were revealed by the decay proton angular correlations which, for dipoles, are of the form 1 + A2P2(cos θ)

  9. Charge Exchange, from the Laboratory to Galaxy Clusters

    Science.gov (United States)

    Betancourt-Martinez, Gabriele; Beiersdorfer, Peter; Brown, Gregory; Hell, Natalie; Leutenegger, Maurice A.; Porter, Frederick S.; Reynolds, Christopher S.

    2016-04-01

    X-ray emission due to charge exchange (CX) between solar wind ions and neutrals in comets and planetary atmospheres is ubiquitous in the solar system, and is also a significant foreground in all observations from low-Earth orbit. It is also possible that CX is common astrophysically, in any environment where hot plasma and cold gas interact. A current challenge is that theoretical models of CX spectra do not always accurately describe observations, and require further experimental verification. This is especially important to focus on now, as the recent launch of Astro-H is providing us with the first high-resolution spectra of extended x-ray sources. In order to improve our understanding and modeling of CX spectra, we take advantage of the laboratory astrophysics program at the Lawrence Livermore National Laboratory and use an Electron Beam Ion Trap (EBIT) to perform CX experiments, using the EBIT Calorimeter Spectrometer. We present experimental benchmarks that can be used to develop a more comprehensive and accurate CX theory. On the observational side, we also investigate the possibility of CX occurring in the filaments around the central galaxy of the Perseus cluster, NGC 1275. We use Chandra ACIS data, combined with what we know about laboratory CX spectra, to investigate the possibility of CX being a significant contributor to the x-ray emission.

  10. The Solar Wind Charge-Exchange Production Factor for Hydrogen

    CERN Document Server

    Kuntz, K D; Collier, M R; Connor, H K; Cravens, T E; Koutroumpa, D; Porter, F S; Robertson, I P; Sibeck, D G; Snowden, S L; Thomas, N E; Wash, B M

    2015-01-01

    The production factor, or broad band averaged cross-section, for solar wind charge-exchange with hydrogen producing emission in the ROSAT 1/4 keV (R12) band is $3.8\\pm0.2\\times10^{-20}$ count degree$^{-2}$ cm$^4$. This value is derived from a comparison of the Long-Term (background) Enhancements in the ROSAT All-Sky Survey with magnetohysdrodynamic simulations of the magnetosheath. This value is 1.8 to 4.5 times higher than values derived from limited atomic data, suggesting that those values may be missing a large number of faint lines. This production factor is important for deriving the exact amount of 1/4 keV band flux that is due to the Local Hot Bubble, for planning future observations in the 1/4 keV band, and for evaluating proposals for remote sensing of the magnetosheath. The same method cannot be applied to the 3/4 keV band as that band, being composed primarily of the oxygen lines, is far more sensitive to the detailed abundances and ionization balance in the solar wind. We also show, incidentally,...

  11. Charge-exchange and charge-conserving reactions on Mg, Ar, Zr, and Sn isotopes

    International Nuclear Information System (INIS)

    We investigate charge-exchange reactions (CEXRs) and charge-conserving reactions (CCORs) on Mg, Ar, Zr, and Sn isotopes by comparing our theoretical results to relevant experimental data on stable nuclei. As for CEXRs, first, we discuss nuclear beta decay because it may give more convincing input data on the network calculations for successive capture reactions by protons and neutrons. Second, we address the importance of the Gamow Teller (GT) states that are low-lying excited states well known in the conventional nuclear physics while high-lying excited states still remain to be studied. The third topic, which is viable through the CCORs, is the symmetry energy associated with the equation of state of nuclear matter. By using the CCORs, we can study the isoscalar giant dipole resonance (ISGDR) and the pigmy dipole resonance (PDR). We discuss theoretical results regarding these CEXRs and CCORs on 26Mg, 40Ar, 90,92Zr, and 112∼124Sn and compare them with available experimental data. Our calculations are carried out by using the proton-neutron quasi-particle random phase approximation (pnQRPA), the QRPA, the deformed QRPA (DQRPA), the shell model and a hybrid model. Our results are shown to agree with the data available. These nuclear reactions considered in this report will complement capture reactions by protons and neutrons which are of vital importance for understanding the element abundances in the cosmos.

  12. Neutrino and antineutrino charge-exchange reactions on 12C

    International Nuclear Information System (INIS)

    We extend the formalism of weak interaction processes, obtaining new expressions for the transition rates, which greatly facilitate numerical calculations, for both neutrino-nucleus reactions and muon capture. Explicit violation of the conserved vector current hypothesis by the Coulomb field, as well as development of a sum-rule approach for inclusive cross sections, has been worked out. We have done a thorough study of exclusive (ground-state) properties of 12B and 12N within the projected quasiparticle random phase approximation (PQRPA). Good agreement with experimental data achieved in this way put into evidence the limitations of the standard RPA and QRPA models, which come from the inability of the RPA to open the p3/2 shell and from the nonconservation of the number of particles in the QRPA. The inclusive neutrino/antineutrino (ν/ν-tilde) reactions 12C(ν,e-)12N and 12C(ν-tilde,e+)12B are calculated within both the PQRPA and the relativistic QRPA. It is found that (i) the magnitudes of the resulting cross sections are close to the sum-rule limit at low energy, but significantly smaller than this limit at high energies, for both ν and ν-tilde; (ii) they increase steadily when the size of the configuration space is augmented, particularly for ν/ν-tilde energies >200 MeV; and (iii) they converge for sufficiently large configuration space and final-state spin. The quasi-elastic 12C(ν,μ-)12N cross section recently measured in the MiniBooNE experiment is briefly discussed. We study the decomposition of the inclusive cross section based on the degree of forbiddenness of different multipoles. A few words are dedicated to the ν/ν-tilde-12C charge-exchange reactions related to astrophysical applications.

  13. Charge Exchange Collisions between Ultracold Fermionic Lithium Atoms and Calcium Ions

    CERN Document Server

    Haze, Shinsuke; Saito, Ryoichi; Mukaiyama, Takashi

    2014-01-01

    An observation of charge exchange collisions between ultracold fermionic 6Li atoms and 40Ca+ ions is reported. The reaction product of the charge exchange collision is dentified via mass spectrometry where the motion of the ions is excited parametrically. We measure the cross section of the charge exchange collisions between the 6Li atoms in the ground state and the 40Ca+ ions in the ground and metastable excited states. Investigation of the inelastic collision characteristics in the atom-ion mixture is an important step toward ultracold chemistry based on ultracold atoms and ions.

  14. Charge exchange cross section database for proton collisions with hydrocarbon molecules

    International Nuclear Information System (INIS)

    The available experimental and theoretical cross section data on charge exchange processes in collisions of protons with hydrocarbon molecules have been collected and critically assessed. Using well established scaling relationships for the charge exchange cross sections at low and high collision energies, as well as the known rate coefficients for these reactions in the thermal energy region, a complete cross sections database is constructed for proton-CxHy charge exchange reactions from thermal energies up to several hundreds keV for all CxHy molecules with x=1,2,3 and 1≤y≤2x+2. (author)

  15. The role of spin exchange in charge transfer in low-bandgap polymer: Fullerene bulk heterojunctions

    International Nuclear Information System (INIS)

    Formation, relaxation and dynamics of polarons and methanofullerene anion radicals photoinitiated in poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′, 3′-benzothiadiazole)]:-[6,6]-phenyl-C61-butyric acid methyl ester (PCDTBT:PC61BM) bulk heterojunctions were studied mainly by light-induced EPR (LEPR) spectroscopy in wide photon energy and temperature ranges. Some polarons are pinned by spin traps whose number and depth are governed by the composite morphology and photon energy. The proximity of the photon energy and the polymer bandgap reduces the number of such traps, inhibits recombination of mobile charge carriers, and facilitates their mobility in polymer network. Spin relaxation and charge carrier dynamics were studied by the steady-state saturation method at wide range of temperature and photon energy. These processes were shown to be governed by spin exchange as well as by the photon energy. Charge transfer in the composite is governed by the polaron scattering on the lattice phonons of crystalline domains embedded into amorphous polymer matrix and its activation hopping between polymer layers. The energy barrier required for polaron interchain hopping exceeds that of its intrachain diffusion. Anisotropy of polaron dynamics in the PCDTBT:PC61BM composite is less than that of poly(3-alkylthiophenes)-based systems that evidences for better ordering of the former. Lorentzian shape of LEPR lines of both charge carriers, lower concentration of spin traps as well as behaviours of the main magnetic resonance parameters were explained by layer ordered morphology of polymer matrix

  16. Ultrafast photoelectron spectroscopy of solutions: space-charge effect

    Science.gov (United States)

    Al-Obaidi, R.; Wilke, M.; Borgwardt, M.; Metje, J.; Moguilevski, A.; Engel, N.; Tolksdorf, D.; Raheem, A.; Kampen, T.; Mähl, S.; Kiyan, I. Yu; Aziz, E. F.

    2015-09-01

    The method of time-resolved XUV photoelectron spectroscopy is applied in a pump-probe experiment on a liquid micro-jet. We investigate how the XUV energy spectra of photoelectrons are influenced by the space charge created due to ionization of the liquid medium by the pump laser pulse. XUV light from high-order harmonic generation is used to probe the electron population of the valence shell of iron hexacyanide in water. By exposing the sample to a short UV pump pulse of 266 nm wavelength and ˜55 fs duration, we observe an energy shift of the spectral component associated with XUV ionization from the Fe 3d(t2g) orbital as well as a shift of the water spectrum. Depending on the sequence of the pump and probe pulses, the arising energy shift of photoelectrons acquires a positive or negative value. It exhibits a sharp positive peak at small time delays, which facilitates to determine the temporal overlap between pump and probe pulses. The negative spectral shift is due to positive charge accumulated in the liquid medium during ionization. Its dissipation is found to occur on a (sub)nanosecond time scale and has a biexponential character. A simple mean-field model is provided to interpret the observations. A comparison between the intensity dependencies of the spectral shift and the UV ionization yield shows that the space-charge effect can be significantly reduced when the pump intensity is attenuated below the saturation level of water ionization. For the given experimental conditions, the saturation intensity lies at 6× {10}10 W cm-2.

  17. Precision spectroscopy of trapped highly charged heavy elements: pushing the limits of theory and experiment

    International Nuclear Information System (INIS)

    Atomic spectroscopy results from the electron beam ion trap at the National Institute of Standards and Technology have generally agreed with the predictions of theory extremely well. An interesting exception is our recent result on the helium isoelectronic sequence at Z = 22, which agrees instead with a meta-analysis of all prior measurements above Z = 15, but disagrees with both theory and a contemporaneous report of an independent measurement at Z = 18 which claims to validate theory to high accuracy. Here, a potential systematic shift involving high-n satellite lines induced by double charge exchange is quantitatively estimated and shown to be potentially significant in experiments involving gasses. Suggestions for further refinements in estimating the magnitude of this systematic shift are given. (paper)

  18. Significance of anion exchange in pentachlorophenol sorption by variable-charge soils.

    Science.gov (United States)

    Hyun, Seunghun; Lee, Linda S; Rao, P Suresh C

    2003-01-01

    Sorption data and subsequent predictive models for evaluating acidic pesticide behavior on variable-charge soils are needed to improve pesticide management and environmental stewardship. Previous work demonstrated that sorption of pentachlorophenol (PCP), a model organic acid, was adequately modeled by accounting for pH-and pKa-dependent chemical speciation and using two organic carbon-normalized sorption coefficients; one each for the neutral and anionic species. Such models do not account for organic anion interaction to positively charged surface sites, which can be significant for variable-charge minerals present in weathered soils typical of tropical and subtropical regions. The role of anion exchange in sorption of ionizable chemicals by variable-charge soils was assessed by measuring sorption of PCP by several variable-charge soils from aqueous solutions of CaCl2, CaSO4, Ca(H2PO4)2 as a function of pH. Differences in sorption from phosphate and chloride electrolyte solutions were attributed to pentachlorophenolate interactions with anion exchange sites. Suppression of PCP sorption by phosphate ranged from negligible in a soil with essentially no positively charge sites, as measured by negligible anion exchange capacity, to as much as 69% for variable-charge soils. Pentachlorophenolate exchange correlated well with the ratio of pH-dependent anion exchange capacity to net surface charge. Sorption reversibility of PCP by both CaCl2 and Ca(H2PO4)2 solutions was also demonstrated. Results for PCP clearly demonstrate that sorption to anion exchange sites in variable-charge soils should be considered in assessing pesticide mobility and that phosphate fertilizer application may increase the mobility of acidic pesticides. PMID:12809297

  19. N(+)-N long-range interaction energies and resonance charge exchange

    Science.gov (United States)

    Stallcop, J. R.; Partridge, H.

    1985-01-01

    The aerothermodynamic studies of proposed space missions require atmospheric charge-transfer data. N2(+) eigenstate energies are calculated with use of the complete-active-space self-consistent-field method with an extended Gaussian basis set. The N(+)-N charge-exchange cross section, determined from these energies, agrees with merged-beam measurements. This contradicts the previous theoretical conclusion. A simple physical description of the long-range interaction is presented and should expedite future charge-transfer studies.

  20. X-ray Signature of Charge Exchange in the Spectra of L-shell Iron Ions

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P; Schweikhard, L; Liebisch, P; Brown, G V

    2007-01-05

    The X-ray signature of charge exchange between highly charged L-shell iron ions and neutral gas atoms was studied in the laboratory in order to assess its diagnostic utility. Significant differences with spectra formed by electron-impact excitation were observed. In particular, a strong enhancement was found of the emission corresponding to n {le} 4 {yields} n = 2 transitions relative to the n = 3 {yields} n = 2 emission. This enhancement was detectable even with relatively low-resolution X-ray instrumentation (E/{Delta}E {approx} 10) and may enable future identification of charge exchange as a line-formation mechanism in astrophysical spectra.

  1. Laboratory simulation of charge exchange-produced X-ray emission from comets.

    Science.gov (United States)

    Beiersdorfer, P; Boyce, K R; Brown, G V; Chen, H; Kahn, S M; Kelley, R L; May, M; Olson, R E; Porter, F S; Stahle, C K; Tillotson, W A

    2003-06-01

    In laboratory experiments using the engineering spare microcalorimeter detector from the ASTRO-E satellite mission, we recorded the x-ray emission of highly charged ions of carbon, nitrogen, and oxygen, which simulates charge exchange reactions between heavy ions in the solar wind and neutral gases in cometary comae. The spectra are complex and do not readily match predictions. We developed a charge exchange emission model that successfully reproduces the soft x-ray spectrum of comet Linear C/1999 S4, observed with the Chandra X-ray Observatory. PMID:12791989

  2. The Contribution of Reggeon in Charge Exchange Processes

    CERN Document Server

    Yu Feng Zhou; Lian Shou Liu; Yufeng, Zhou; Hongan, Peng; Lianshou, Liu

    1998-01-01

    We discuss in this paper The experimental results on maximum psedo-rapidity Collaboration at HERA. We calculate the contributions of \\regg ($\\rho$-Reggeon associated with $\\rho$ meson) from regge phenomenology and $\\pi^{+}$-exchange from pion cloud model. The results show that neither the \\regg-exchange nor the pion cloud model alone can explain the experimental data well, but after considering both these two processes together, by using Monte Carlo simulation, a good agreement between theoretical results and experimental data is found. This means that in discussing the large rapidity gap phenomena in deep inelastic scattering, both of the two processes play substantial role.

  3. Pion induced double-charge exchange above the resonance

    International Nuclear Information System (INIS)

    The zero degree excitation function for (π+, π-) is calculated for pion energies of 300 to 1400 MeV assuming a sequential mechanism. The cross section around 1225 MeV is 104 smaller than at 800 MeV. Experiments at this energy should be ideal for searches for effects due to exchange currents, and other non-conventional mechanisms. 15 refs

  4. X-Ray Emission Cross Sections following Charge Exchange by Multiply-Charged Ions of Astrophysical Interest

    Energy Technology Data Exchange (ETDEWEB)

    Otranto, S; Olson, R E; Beiersdorfer, P

    2007-03-12

    The CTMC method is used to calculate emission cross sections following charge exchange processes involving highly charged ions of astrophysical interest and typical cometary targets. Comparison is made to experimental data obtained on the EBIT-I machine at Lawrence Livermore National Laboratory LLNL for O{sup 8+} projectiles impinging on different targets at a collision energy of 10 eV/amu. The theoretical cross sections are used together with ion abundances measured by the Advanced Composition Explorer to reproduce cometary spectra. Discrepancies due to different estimated delays of solar wind events between the comet and the Earth-orbiting satellite are discussed.

  5. Charge Carrier Conduction Mechanism in PbS Quantum Dot Solar Cells: Electrochemical Impedance Spectroscopy Study.

    Science.gov (United States)

    Wang, Haowei; Wang, Yishan; He, Bo; Li, Weile; Sulaman, Muhammad; Xu, Junfeng; Yang, Shengyi; Tang, Yi; Zou, Bingsuo

    2016-07-20

    With its properties of bandgap tunability, low cost, and substrate compatibility, colloidal quantum dots (CQDs) are becoming promising materials for optoelectronic applications. Additionally, solution-processed organic, inorganic, and hybrid ligand-exchange technologies have been widely used in PbS CQDs solar cells, and currently the maximum certified power conversion efficiency of 9.9% has been reported by passivation treatment of molecular iodine. Presently, there are still some challenges, and the basic physical mechanism of charge carriers in CQDs-based solar cells is not clear. Electrochemical impedance spectroscopy is a monitoring technology for current by changing the frequency of applied alternating current voltage, and it provides an insight into its electrical properties that cannot be measured by direct current testing facilities. In this work, we used EIS to analyze the recombination resistance, carrier lifetime, capacitance, and conductivity of two typical PbS CQD solar cells Au/PbS-TBAl/ZnO/ITO and Au/PbS-EDT/PbS-TBAl/ZnO/ITO, in this way, to better understand the charge carriers conduction mechanism behind in PbS CQD solar cells, and it provides a guide to design high-performance quantum-dots solar cells. PMID:27176547

  6. 1H and 23Na MAS NMR spectroscopy of cationic species in CO2 selective alkaline earth metal porous silicoaluminophosphates prepared via liquid and solid state ion exchange

    Science.gov (United States)

    Arévalo-Hidalgo, Ana G.; Dugar, Sneha; Fu, Riqiang; Hernández-Maldonado, Arturo J.

    2012-07-01

    The location of extraframework cations in Sr2+ and Ba2+ ion-exchanged SAPO-34 was estimated by means of 1H and 23Na MAS NMR spectroscopy and spectral deconvolution. Incorporation of the alkaline earth metal cations onto the SAPO framework was achieved via liquid state ion exchange, coupled partial detemplation/solid-state ion exchange, and combination of both techniques. MAS NMR revealed that the level of ion exchange was limited by the presence of protons and sodium cations near hexagonal prisms (site SI), which are relatively difficult to exchange with the alkaline earth metal due to steric and charge repulsion criteria. In addition, the presence of ammonium cations in the supercages facilitated the exchange of otherwise tenacious hydrogen as corroborated by unit cell compositional data as well as enhanced CO2 adsorption at low partial pressures. The extraframework ammonium species were produced from partial detemplation of the structure-directing agent employed for the SAPO-34 synthesis, tetraethylammonium.

  7. Removal of charged micropollutants from water by ion-exchange polymers -- effects of competing electrolytes.

    Science.gov (United States)

    Bäuerlein, Patrick S; Ter Laak, Thomas L; Hofman-Caris, Roberta C H M; de Voogt, Pim; Droge, Steven T J

    2012-10-15

    A wide variety of environmental compounds of concern, e.g. pharmaceuticals or illicit drugs, are acids or bases that may predominantly be present as charged species in drinking water sources. These charged micropollutants may prove difficult to remove by currently used water treatment steps (e.g. UV/H(2)O(2), activated carbon (AC) or membranes). We studied the sorption affinity of some ionic organic compounds to both AC and different charged polymeric materials. Ion-exchange polymers may be effective as additional extraction phases in water treatment, because sorption of all charged compounds to oppositely charged polymers was stronger than to AC, especially for the double-charged cation metformin. Tested below 1% of the polymer ion-exchange capacity, the sorption affinity of charged micropollutants is nonlinear and depends on the composition of the aqueous medium. Whereas oppositely charged electrolytes do not impact sorption of organic ions, equally charged electrolytes do influence sorption indicating ion-exchange (IE) to be the main sorption mechanism. For the tested polymers, a tenfold increased salt concentration lowered the IE-sorption affinity by a factor two. Different electrolytes affect IE with organic ions in a similar way as inorganic ions on IE-resins, and no clear differences in this trend were observed between the sulphonated and the carboxylated cation-exchanger. Sorption of organic cations is five fold less in Ca(2+) solutions compared to similar concentrations of Na(+), while that of anionic compounds is three fold weaker in SO(4)(2-) solutions compared to equal concentrations of Cl(-). PMID:22818952

  8. Atomic hydrogen escape rate due to charge exchange with hot plasmaspheric ions

    Science.gov (United States)

    Maher, L. J.; Tinsley, B. A.

    1977-01-01

    Data on ion and electron temperatures and concentrations to several thousand kilometers of altitude were obtained from the Atmosphere Explorer C satellite for 1974 and to 850 km from Arecibo incoherent scatter radar measurements. These data were used to normalize diffusive equilibrium profiles. From these profiles and by using the neutral atmospheric model of Jacchia (1971) and a new hydrogen model, the charge-exchange-induced neutral hydrogen escape fluxes for equatorial and middle latitudes were calculated. The data confirm earlier estimates that the charge exchange loss is more important than Jeans escape for the earth. It is also found that inside the plasmapause this charge exchange process with hot plasmapheric ions is the major production and loss process for the satellite population in the hydrogen geocorona.

  9. The diurnal and solar cycle variation of the charge exchange induced hydrogen escape flux

    Science.gov (United States)

    Maher, L. J.; Tinsley, B. A.

    1978-01-01

    On the basis of ion temperature and density data at specific points and times in June 1969 provided by the OGO 6 satellite, and altitude profiles of the ion and electron temperature and concentration provided by the Arecibo radar facility over the period February 1972-April 1974, the diurnal and solar cycle variation of the charge-exchange-induced hydrogen escape flux was investigated. It was calculated that for low to moderate solar activity at Arecibo, the diurnal ratio of the maximum-to-minimum charge-exchange-induced hydrogen escape flux was approximately 6 with a peak around noon and a minimum somewhere between 0100 and 0300 h LT. This study of a limited amount of OGO 6 and Arecibo data seems to indicate that the charge-exchange-induced hydrogen escape flux increases as the F(10.7) flux increases for low to moderate solar activity.

  10. X-ray emission measurements following charge exchange between C$^{6+}$ and H$_2$

    CERN Document Server

    Fogle, M; Morgan, K; McCammon, D; Seely, D G; Draganić, I N; Havener, C C

    2014-01-01

    Lyman x-ray spectra following charge exchange between C$^{6+}$ and H$_2$ are presented for collision velocities between 400 and 2300 km/s (1--30 keV/amu). Spectra were measured by a microcalorimeter x-ray detector capable of fully resolving the C VI Lyman series emission lines though Lyman-$\\delta$. The ratios of the measured emission lines are sensitive to the angular momentum $l$-states populated during charge exchange and are used to gauge the effectiveness of different $l$-distribution models in predicting Lyman emission due to charge exchange. At low velocities, we observe that both single electron capture and double capture autoionization contribute to Lyman emission and that a statistical $l$-distribution best describes the measured line ratios. At higher velocities single electron capture dominates with the $l$-distribution peaked at the maximum $l$.

  11. Charge Exchange Reaction in Dopant-Assisted Atmospheric Pressure Chemical Ionization and Atmospheric Pressure Photoionization

    Science.gov (United States)

    Vaikkinen, Anu; Kauppila, Tiina J.; Kostiainen, Risto

    2016-04-01

    The efficiencies of charge exchange reaction in dopant-assisted atmospheric pressure chemical ionization (DA-APCI) and dopant-assisted atmospheric pressure photoionization (DA-APPI) mass spectrometry (MS) were compared by flow injection analysis. Fourteen individual compounds and a commercial mixture of 16 polycyclic aromatic hydrocarbons were chosen as model analytes to cover a wide range of polarities, gas-phase ionization energies, and proton affinities. Chlorobenzene was used as the dopant, and methanol/water (80/20) as the solvent. In both techniques, analytes formed the same ions (radical cations, protonated molecules, and/or fragments). However, in DA-APCI, the relative efficiency of charge exchange versus proton transfer was lower than in DA-APPI. This is suggested to be because in DA-APCI both dopant and solvent clusters can be ionized, and the formed reagent ions can react with the analytes via competing charge exchange and proton transfer reactions. In DA-APPI, on the other hand, the main reagents are dopant-derived radical cations, which favor ionization of analytes via charge exchange. The efficiency of charge exchange in both DA-APPI and DA-APCI was shown to depend heavily on the solvent flow rate, with best efficiency seen at lowest flow rates studied (0.05 and 0.1 mL/min). Both DA-APCI and DA-APPI showed the radical cation of chlorobenzene at 0.05-0.1 mL/min flow rate, but at increasing flow rate, the abundance of chlorobenzene M+. decreased and reagent ion populations deriving from different gas-phase chemistry were recorded. The formation of these reagent ions explains the decreasing ionization efficiency and the differences in charge exchange between the techniques.

  12. Inclusive double-charge-exchange π- production at 100 GeV/c

    International Nuclear Information System (INIS)

    Measurements of inclusive cross sections at 100 GeV/c are presented for the double-charge-exchange reactions a+p → π-X with a = π, K, or p. The measurements covered a kinematic range in the Feynman x variable of 0.3 - production is used to fit the data and demonstrates the importance of resonance production via one-pion exchange for large values of the Feynman x

  13. Charge exchange momentum transfer due to ion beam injection in partially ionized plasmas

    International Nuclear Information System (INIS)

    Time responses of a helium plasma to helium gas puffing without and with helium beam injection in a linear plasma device are experimentally investigated. Increase in the neutral density due to gas puffing is suppressed by ion beam injection. The experimental results show that a momentum transport from the ion beam to the puffed neutral particles occurs due to the charge exchange interaction, suggesting that charge exchange momentum transport is one of the processes responsible for the spatial redistribution of neutral atoms in partially ionized plasmas. (author)

  14. New charge exchange model of GEANT4 for 9Be(p,n)9B reaction

    International Nuclear Information System (INIS)

    A new data-based charge exchange model of GEANT4 dedicated to the 9Be(p,n)9B reaction is developed by taking the ENDF/B-VII.1 differential cross-section data as input. Our model yields results that are in good agreement with the experimental neutron yield spectrum data obtained for proton beams of energy (20–35) MeV. In particular, in contrast to all the considered GEANT4 hadronic models, the peak structure resulting from the discrete neutrons generated by the charge-exchange reaction is observed to be accurately reproduced in our model

  15. Solar wind charge exchange X-ray emission from Mars Model and data comparison

    OpenAIRE

    Koutroumpa, Dimitra; Modolo, Ronan; Chanteur, Gerard; Chaufray, Jean-Yves; Kharchenko, Vasili; Lallement, Rosine

    2012-01-01

    Aims. We study the soft X-ray emission induced by charge exchange (CX) collisions between solar-wind, highly charged ions and neutral atoms of the Martian exosphere. Methods. A 3D multi species hybrid simulation model with improved spatial resolution (130 km) is used to describe the interaction between the solar wind and the Martian neutrals. We calculated velocity and density distributions of the solar wind plasma in the Martian environment with realistic planetary ions description, using sp...

  16. Ion slowing down and charge exchange at small impact parameters selected by channeling: superdensity effects

    OpenAIRE

    L'Hoir, A.; Adoui, A.; Barrué, F.; Billebaud, A.; Bosch, F.; Bräuning-Demian, A.; Bräuning, H.; Cassimi, A.; Chevallier, M.; C. Cohen; Dauvergne, D; Demonchy, C.E.; Giot, L.; Kirsch, R.; Gumberidze, A

    2005-01-01

    In two experiments performed with 20-30 MeV/u highly charged heavy ions (Pb56+, U91+) channeled through thin silicon crystals, we observed the original features of superdensity, associated to the glancing collisions with atomic rows undergone by part of the incident projectiles. In particular the very high collision rate yields a quite specific charge exchange regime, that leads to a higher ionization probability than in random conditions. X-ray measurements show that electrons captured in ou...

  17. Resonant behaviour in double charge exchange reaction of π+-mesons on the nuclear photoemulsion

    International Nuclear Information System (INIS)

    The invariant-mass spectra of the ppπ- and pp systems produced in the double charge exchange (DCX) of positively charged pions on photoemulsion are analysed. A pronounced peak is observed in the ppπ- invariant-mass spectrum, while the Mpp spectrum exhibits a strong Migdal-Watson effect of the proton-proton final-state interaction. These findings are in favor of the NN-decoupled NN π pseudoscalar resonance with T=0 called d'

  18. Method of producing weakly acidic cation exchange resin particles charged with uranyl ions

    Energy Technology Data Exchange (ETDEWEB)

    Abdelmonem, N.; Ringel, H.; Zimmer, E.

    1981-07-21

    Weakly acidic cationic ion exchange resin particles are charged with uranyl ions by contacting the particles step wise with aqueous uranyl nitrate solution at higher uranium concentrations from stage to stage. An alkaline medium is added to the uranyl nitrate solution in each stage to increase the successive pH values of the uranyl nitrate solution contacting the particles in dependence upon the uranium concentration effective for maximum charging of the particles with uranyl ions.

  19. Background charges and quantum effects in quantum dots transport spectroscopy

    OpenAIRE

    Pierre M.; Hofheinz M.; Jehl X.; Sanquer M.; Molas G.; Vinet M.; Deleonibus S.

    2009-01-01

    We extend a simple model of a charge trap coupled to a single-electron box to energy ranges and parameters such that it gives new insights and predictions readily observable in many experimental systems. We show that a single background charge is enough to give lines of differential conductance in the stability diagram of the quantum dot, even within undistorted Coulomb diamonds. It also suppresses the current near degeneracy of the impurity charge, and yields negative differential lines far ...

  20. Longitudinal exchange: an alternative strategy towards quantification of dynamics parameters in ZZ exchange spectroscopy

    International Nuclear Information System (INIS)

    Longitudinal exchange experiments facilitate the quantification of the rates of interconversion between the exchanging species, along with their longitudinal relaxation rates, by analyzing the time-dependence of direct correlation and exchange cross peaks. Here we present a simple and robust alternative to this strategy, which is based on the combination of two complementary experiments, one with and one without resolving exchange cross peaks. We show that by combining the two data sets systematic errors that are caused by differential line-broadening of the exchanging species are avoided and reliable quantification of kinetic and relaxation parameters in the presence of additional conformational exchange on the ms–μs time scale is possible. The strategy is applied to a bistable DNA oligomer that displays different line-broadening in the two exchanging species.

  1. Total cross sections for pion charge exchange on the proton

    Energy Technology Data Exchange (ETDEWEB)

    Breitschopf, J.

    2006-04-28

    This work describes the measurement of total SCX cross sections employing a new 4{pi} scintillation counter to perform transmission measurements in the incident pion energy range from about 38 to 250 MeV. A small 4{pi} detector box consisting of thin plastic scintillators has been constructed. The transmission technique, which was used, relates the number of transmitted charged pions to that of incident beam pions and this way effectively counts events with neutral products. The incoming negative pions were counted by three beam defining counters before they hit a target of very well known size and chemical composition. The target was placed in the box detector which was not sensitive to the neutral particles resulting from the SCX. The total cross section for emerging neutral particles was derived from the comparison of the numbers of the incoming and transmitted charged particles. The total SCX cross section on hydrogen was derived from the transmissions of a CH{sub 2} target, a carbon target and an empty target. For a detailed offline analysis all TDC, QDC and FADC information was recorded in an event by event mode for each triggered beam event. Various corrections had to be applied to the data, such as random correction, the detection of neutrals in the detector, Dalitz decay, pion decay and the radiative pion capture. This measurement covers, as the only experiment, the whole {delta}-resonance and the sp-interference region in one single experimental setup and improves the available data base for the SCX reaction. It is shown that the description of the SCX cross sections is improved if the s-wave amplitudes, that have been fixed essentially by elastic pion-nucleon scattering data, is reduced by (4{+-}1.5)%. The exact value depends on the SCX literature data included and on the parameters of the {delta}{sup 0} Breit-Wigner resonance describing the p{sub 33}-waves. This shows that p-wave as well as s-wave effects should be considered in studies of isospin

  2. Total cross sections for pion charge exchange on the proton

    International Nuclear Information System (INIS)

    This work describes the measurement of total SCX cross sections employing a new 4π scintillation counter to perform transmission measurements in the incident pion energy range from about 38 to 250 MeV. A small 4π detector box consisting of thin plastic scintillators has been constructed. The transmission technique, which was used, relates the number of transmitted charged pions to that of incident beam pions and this way effectively counts events with neutral products. The incoming negative pions were counted by three beam defining counters before they hit a target of very well known size and chemical composition. The target was placed in the box detector which was not sensitive to the neutral particles resulting from the SCX. The total cross section for emerging neutral particles was derived from the comparison of the numbers of the incoming and transmitted charged particles. The total SCX cross section on hydrogen was derived from the transmissions of a CH2 target, a carbon target and an empty target. For a detailed offline analysis all TDC, QDC and FADC information was recorded in an event by event mode for each triggered beam event. Various corrections had to be applied to the data, such as random correction, the detection of neutrals in the detector, Dalitz decay, pion decay and the radiative pion capture. This measurement covers, as the only experiment, the whole Δ-resonance and the sp-interference region in one single experimental setup and improves the available data base for the SCX reaction. It is shown that the description of the SCX cross sections is improved if the s-wave amplitudes, that have been fixed essentially by elastic pion-nucleon scattering data, is reduced by (4±1.5)%. The exact value depends on the SCX literature data included and on the parameters of the Δ0 Breit-Wigner resonance describing the p33-waves. This shows that p-wave as well as s-wave effects should be considered in studies of isospin symmetry breaking. Interestingly, our

  3. The role of electron capture and energy exchange of positively charged particles passing through matter

    OpenAIRE

    Ulmer, W.

    2011-01-01

    The conventional treatment of the Bethe-Bloch equation for protons accounts for electron capture at the end of the projectile track by the small Barkas correction. This is only a possible way for protons, whereas for light and heavier charged nuclei the exchange of energy and charge along the track has to be accounted for by regarding the projectile charge q as a function of the residual energy. This leads to a significant modification of the Bethe-Bloch equation, otherwise the range in a med...

  4. Development of the charge exchange type beam scraper system at the J-PARC

    Science.gov (United States)

    Okabe, K.; Yamamoto, K.; Kinsho, M.

    2016-03-01

    Improvement in injection beam quality at the Japan Proton Accelerator Research Complex 3-GeV rapid cycle synchrotron is to mitigate beam loss at the injection section. We developed a charge-exchange type scraper system with a thin carbon foil to collimate the beam halo in the injection beam line of the synchrotron. The key issue to realize the scraper is a reduction of the beam loss induced by the multiple-scattering effect of charge-exchange foil placed at the scraper head. In order to determine the adequate foil thickness, a charge-exchange efficiency of a carbon foil and particle-tracking simulation study of the collimated beam have been performed assuming a realistic halo at the scraper section. Using the results of this study, we chose the thickness of a 520 μg /cm2 as the scraper foils to mitigate radiation dose around the L3BT scraper section. A charge-exchange scraper system that prevents the emission of radioactive fragments of the carbon foil was build. The system was put into operation to prove its effectiveness in eliminating the beam halo. From the result of a preliminary beam experiments, we confirmed that the installed scrapers eliminate a transverse beam tail or halo. After two days of operation with beam collimation, the radiation dose level around the scraper section was a tolerable one for the hands-on maintenance.

  5. Antiproton small momentum transfer charge exchange scattering on protons at 30 GeV/c

    International Nuclear Information System (INIS)

    Antiproton charge exchange scattering on protons anti pp→anti nn is investigated with 30 GeV/c antiprotons at the IHEP accelerator. The experiment confirms the existence of a structure at small angles in the angular distribution of this reaction at high energies, observed earlier

  6. Short-range NN and NΔ correlations in pion double charge exchange (DCX)

    International Nuclear Information System (INIS)

    I will review several important results related to the short-range nucleon-nucleon and delta-nucleon interaction that have been obtained from recent studies of pion double charge exchange in selected nuclei. 32 refs., 5 figs., 3 tabs

  7. Performance study of the TFTR diagnostic neutral beam for active charge exchange measurements

    International Nuclear Information System (INIS)

    A neutral beam source will be incorporated in the Tokamak Fusion Test Reactor (TFTR) charge exchange diagnostic to provide a time modulated, spatially localized enhancement of the charge exchange efflux. Two autonomous Charge Exchange Neutral Analyzer (CENA) systems are being designed for the TFTR. One system measures the plasma ion temperature along twelve vertical line-of-sight chords spaced approximately equidistantly across the torus minor diameter. The other system is dedicated primarily to measurement of ion phenomena associated with neutral beam injection heating and has a fan-like field of view along eight sight-lines in the equitorial plane. The neutral beam is steerable in order to access the viewing field of both CENA systems, though in general not simultaneously. The performance of the diagnostic neutral beam is evaluated to determine the optimal beam specifications for active charge exchange measurements. Using the optimal beam design parameters, the efficacy of the neutral doping is examined for both CENA systems over the envisioned range of the TFTR plasma density and temperature

  8. Neutron-proton charge exchange scattering from 9 to 23 GeV/c

    International Nuclear Information System (INIS)

    The differential cross sections for neutron-proton charge-exchange scattering have been measured with high statistics in the region of momentum transfer squared 0.0022 and for incident neutron momenta 9< p<=23 GeV/c. (Auth.)

  9. Exchange NMR spectroscopy in solids: application in large-scale conformational biopolymer dynamics studies

    International Nuclear Information System (INIS)

    The exchange NMR experiment compares resonant frequencies of a magnetic nucleus before and after the so-called mixing time, thereby gaining molecular dynamics information on millisecond and second correlation time scales. Although exchange NMR experiments on solutions have a long history, conducting them on solids presents methodological challenges, and it was only in the late 1990s that solid-state exchange spectroscopy matured to the level where such complex entities as biopolymers could be addressed. In this review, major methodological advances in the field are examined and the application of exchange NMR experiments to conformational molecular dynamics of solid-state biopolymers is described. (reviews of topical problems)

  10. Charge exchange and energy loss of slowed down heavy ions channeled in silicon crystals

    International Nuclear Information System (INIS)

    This work is devoted to the study of charge exchange processes and of the energy loss of highly charged heavy ions channeled in thin silicon crystals. The two first chapters present the techniques of heavy ion channeling in a crystal, the ion-electron processes and the principle of our simulations (charge exchange and trajectory of channeled ions). The next chapters describe the two experiments performed at the GSI facility in Darmstadt, the main results of which follow: the probability per target atom of the mechanical capture (MEC) of 20 MeV/u U91+ ions as a function of the impact parameter (with the help of our simulations), the observation of the strong polarization of the target electron gas by the study of the radiative capture and the slowing down of Pb81+ ions from 13 to 8,5 MeV/u in channeling conditions for which electron capture is strongly reduced. (author)

  11. Meson exchange current and three-body force contributions to the 4He charge form factor

    International Nuclear Information System (INIS)

    Effects of meson exchange current (MEC) on the charge form factor (CFF) and charge density of 4He are investigated, including pair, mesonic and retardation current terms. The influence of three-body force (3BF) is considered by adopting the realistic wave function obtained from the nuclear Hamiltonian which explicitly includes the two-pion exchange 3BF. As a result the 3BF is found to greatly enhance the MEC contribution. When the 3BF is taken into account, the MEC contribution is shown to remove most of the discrepancy between the theoretical and experimental CFF's at the second maximum. Resulting effects on the charge density are found to yield a depression in the central region. (author)

  12. Stochastic Simulation of Chemical Exchange in Two Dimensional Infrared Spectroscopy

    CERN Document Server

    Sanda, F; Sanda, Frantisek; Mukamel, Shaul

    2006-01-01

    The stochastic Liouville equations are employed to investigate the combined signatures of chemical exchange (two-state-jump) and spectral diffusion (coupling to an overdamped Brownian oscillator) in the coherent response of an anharmonic vibration to three femtosecond infrared pulses. Simulations reproduce the main features recently observed in the OD stretch of phenol in benzene.

  13. Achievement of the charge exchange work diminishing of an internal combustion engine in part load

    Directory of Open Access Journals (Sweden)

    Stefan POSTRZEDNIK

    2012-01-01

    Full Text Available Internal combustion engines, used for driving of different cars, occurs not only at full load, but mostly at the part load. The relative load exchange work at the full (nominal engine load is significantly low. At the part load of the IC engine its energy efficiency ηe is significantly lower than in the optimal (nominal field range of the performance parameters. One of the numerous reasons of this effect is regular growing of the relative load exchange work of the IC engine. It is directly connected with the quantitative regulation method commonly used in the IC engines. From the thermodynamic point of view - the main reason of this effect is the throttling process (causing exergy losses occurring in the inlet and outlet channels. The known proposals for solving of this problem are based on applying of the fully electronic control of the motion of inlet, outlet valves and new reference cycles.The idea presented in the paper leads to diminishing the charge exchange work of the IC engines. The problem can be solved using presented in the paper a new concept of the reference cycle (called as eco-cycle of IC engine. The work of the engine basing on the eco-cycle occurs in two 3-stroke stages; the fresh air is delivered only once for both stages, but in range of each stage a new portion of fuel is burned. Normally the charge exchange occurs once during each engine cycle realized. Elaborated proposition bases on the elimination of chosen charge exchange processes and through this the dropping of the charge exchange work can be achieved.

  14. A Markov chain approach to modelling charge exchange processes of an ion beam in monotonically increasing or decreasing potentials

    International Nuclear Information System (INIS)

    A Markov chain method is presented as an alternative approach to Monte Carlo simulations of charge exchange collisions by an energetic hydrogen ion beam with a cold background hydrogen gas. This method was used to determine the average energy of the resulting energetic neutrals along the path of the beam. A comparison with Monte Carlo modelling showed a good agreement but with the advantage that it required much less computing time and produced no numerical noise. In particular, the Markov chain method works well for monotonically increasing or decreasing electrostatic potentials. Finally, a good agreement is obtained with experimental results from Doppler shift spectroscopy on energetic beams from a hollow cathode discharge. In particular, the average energy of ions that undergo charge exchange reaches a plateau that can be well below the full energy that might be expected from the applied voltage bias, depending on the background gas pressure. For example, pressures of ∼20 mTorr limit the ion energy to ∼20% of the applied voltage

  15. Charge-dependent many-body exchange and dispersion interactions in combined QM/MM simulations

    International Nuclear Information System (INIS)

    Accurate modeling of the molecular environment is critical in condensed phase simulations of chemical reactions. Conventional quantum mechanical/molecular mechanical (QM/MM) simulations traditionally model non-electrostatic non-bonded interactions through an empirical Lennard-Jones (LJ) potential which, in violation of intuitive chemical principles, is bereft of any explicit coupling to an atom’s local electronic structure. This oversight results in a model whereby short-ranged exchange-repulsion and long-ranged dispersion interactions are invariant to changes in the local atomic charge, leading to accuracy limitations for chemical reactions where significant atomic charge transfer can occur along the reaction coordinate. The present work presents a variational, charge-dependent exchange-repulsion and dispersion model, referred to as the charge-dependent exchange and dispersion (QXD) model, for hybrid QM/MM simulations. Analytic expressions for the energy and gradients are provided, as well as a description of the integration of the model into existing QM/MM frameworks, allowing QXD to replace traditional LJ interactions in simulations of reactive condensed phase systems. After initial validation against QM data, the method is demonstrated by capturing the solvation free energies of a series of small, chlorine-containing compounds that have varying charge on the chlorine atom. The model is further tested on the SN2 attack of a chloride anion on methylchloride. Results suggest that the QXD model, unlike the traditional LJ model, is able to simultaneously obtain accurate solvation free energies for a range of compounds while at the same time closely reproducing the experimental reaction free energy barrier. The QXD interaction model allows explicit coupling of atomic charge with many-body exchange and dispersion interactions that are related to atomic size and provides a more accurate and robust representation of non-electrostatic non-bonded QM/MM interactions

  16. Charge-dependent many-body exchange and dispersion interactions in combined QM/MM simulations

    Energy Technology Data Exchange (ETDEWEB)

    Kuechler, Erich R. [BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854-8087 (United States); Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455-0431 (United States); Giese, Timothy J.; York, Darrin M. [BioMaPS Institute and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854-8087 (United States)

    2015-12-21

    Accurate modeling of the molecular environment is critical in condensed phase simulations of chemical reactions. Conventional quantum mechanical/molecular mechanical (QM/MM) simulations traditionally model non-electrostatic non-bonded interactions through an empirical Lennard-Jones (LJ) potential which, in violation of intuitive chemical principles, is bereft of any explicit coupling to an atom’s local electronic structure. This oversight results in a model whereby short-ranged exchange-repulsion and long-ranged dispersion interactions are invariant to changes in the local atomic charge, leading to accuracy limitations for chemical reactions where significant atomic charge transfer can occur along the reaction coordinate. The present work presents a variational, charge-dependent exchange-repulsion and dispersion model, referred to as the charge-dependent exchange and dispersion (QXD) model, for hybrid QM/MM simulations. Analytic expressions for the energy and gradients are provided, as well as a description of the integration of the model into existing QM/MM frameworks, allowing QXD to replace traditional LJ interactions in simulations of reactive condensed phase systems. After initial validation against QM data, the method is demonstrated by capturing the solvation free energies of a series of small, chlorine-containing compounds that have varying charge on the chlorine atom. The model is further tested on the S{sub N}2 attack of a chloride anion on methylchloride. Results suggest that the QXD model, unlike the traditional LJ model, is able to simultaneously obtain accurate solvation free energies for a range of compounds while at the same time closely reproducing the experimental reaction free energy barrier. The QXD interaction model allows explicit coupling of atomic charge with many-body exchange and dispersion interactions that are related to atomic size and provides a more accurate and robust representation of non-electrostatic non-bonded QM

  17. Anion Exchange Capacity As a Mechanism for Deep Soil Carbon Storage in Variable Charge Soils

    Science.gov (United States)

    Dietzen, C.; James, J. N.; Ciol, M.; Harrison, R. B.

    2014-12-01

    Soil is the most important long-term sink for carbon (C) in terrestrial ecosystems, containing more C than plant biomass and the atmosphere combined. However, soil has historically been under-represented in C cycling literature, especially in regards to information about subsurface (>1.0 m) layers and processes. Previous research has indicated that Andisols with large quantities of noncrystalline, variable-charge minerals, including allophane, imogolite, and ferrihydrite, contain more C both in total and at depth than other soil types in the Pacific Northwest. The electrostatic charge of variable-charge soils depends on pH and is sometimes net positive, particularly in acid conditions, such as those commonly developed under the coniferous forests of the Pacific Northwest. However, even soils with a net negative charge may contain a mixture of negative and positive exchange sites and can hold some nutrient anions through the anion exchange capacity. To increase our understanding of the effects of variable-charge on soil organic matter stabilization, deep sampling is under way at the Fall River Long-Term Soil Productivity Site in western Washington. This site has a deep, well-drained soil with few rocks, which developed from weathered basalt and is classified as an Andisol of the Boistfort Series. Samples have been taken to a depth of 3 m at eight depth intervals. In addition to analyzing total soil C, these soils will be analyzed to determine functional groups present, cation exchange capacity, anion exchange capacity, and non-crystalline mineral content. These data will be analyzed to determine any correlations that may exist between these mineralogical characteristics, total soil C, and types of functional groups stored at depth. The most abundant organic functional groups, including carboxylic and phenolic groups, are anionic in nature, and soil positive charge may play an important role in binding and stabilizing soil organic matter and sequestering C.

  18. Charge-exchange x-ray spectra: Evidence for significant contributions from radiative decays of doubly excited states

    Science.gov (United States)

    Ali, R.; Beiersdorfer, P.; Harris, C. L.; Neill, P. A.

    2016-01-01

    Charge-exchange collisions of slow Ne+10 ions with He, Ne, and Ar targets were studied with simultaneous x-ray and cold-target recoil-ion-momentum spectroscopy proving the contribution of several mechanisms to the radiative stabilization of apparent (4,4) doubly excited states for He and Ne targets and of (5,6) states for Ar. In particular, the stabilization efficiency of the mechanism of dynamic auto-transfer to Rydberg states is confirmed. Moreover, we present evidence for direct radiative decays of (4,4) states populated in collisions with He, which is an experimental indication of the population of so-called unnatural-parity states in such collisions. These mechanisms lead to the emission of x-rays that have considerably higher energies than those predicted by current spectral models and may explain recent observations of anomalously large x-ray emission from Rydberg levels.

  19. Cyclic voltammetry on sputter-deposited films of electrochromic Ni oxide: Power-law decay of the charge density exchange

    International Nuclear Information System (INIS)

    Ni-oxide-based thin films were produced by reactive direct-current magnetron sputtering and were characterized by X-ray diffraction and Rutherford backscattering spectroscopy. Intercalation of Li+ ions was accomplished by cyclic voltammetry (CV) in an electrolyte of LiClO4 in propylene carbonate, and electrochromism was documented by spectrophotometry. The charge density exchange, and hence the optical modulation span, decayed gradually upon repeated cycling. This phenomenon was accurately described by an empirical power law, which was valid for at least 104 cycles when the applied voltage was limited to 4.1 V vs Li/Li+. Our results allow lifetime assessments for one of the essential components in an electrochromic device such as a “smart window” for energy-efficient buildings.

  20. Cyclic voltammetry on sputter-deposited films of electrochromic Ni oxide: Power-law decay of the charge density exchange

    Science.gov (United States)

    Wen, Rui-Tao; Granqvist, Claes G.; Niklasson, Gunnar A.

    2014-10-01

    Ni-oxide-based thin films were produced by reactive direct-current magnetron sputtering and were characterized by X-ray diffraction and Rutherford backscattering spectroscopy. Intercalation of Li+ ions was accomplished by cyclic voltammetry (CV) in an electrolyte of LiClO4 in propylene carbonate, and electrochromism was documented by spectrophotometry. The charge density exchange, and hence the optical modulation span, decayed gradually upon repeated cycling. This phenomenon was accurately described by an empirical power law, which was valid for at least 104 cycles when the applied voltage was limited to 4.1 V vs Li/Li+. Our results allow lifetime assessments for one of the essential components in an electrochromic device such as a "smart window" for energy-efficient buildings.

  1. Cyclic voltammetry on sputter-deposited films of electrochromic Ni oxide: Power-law decay of the charge density exchange

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Rui-Tao, E-mail: Ruitao.Wen@angstrom.uu.se; Granqvist, Claes G.; Niklasson, Gunnar A. [Department of Engineering Sciences, The A°ngström Laboratory, Uppsala University, P. O. Box 534, SE-75121 Uppsala (Sweden)

    2014-10-20

    Ni-oxide-based thin films were produced by reactive direct-current magnetron sputtering and were characterized by X-ray diffraction and Rutherford backscattering spectroscopy. Intercalation of Li{sup +} ions was accomplished by cyclic voltammetry (CV) in an electrolyte of LiClO{sub 4} in propylene carbonate, and electrochromism was documented by spectrophotometry. The charge density exchange, and hence the optical modulation span, decayed gradually upon repeated cycling. This phenomenon was accurately described by an empirical power law, which was valid for at least 10{sup 4} cycles when the applied voltage was limited to 4.1 V vs Li/Li{sup +}. Our results allow lifetime assessments for one of the essential components in an electrochromic device such as a “smart window” for energy-efficient buildings.

  2. Charge exchange in H{sup +} grazing scattering off clean and AlF{sub 3} covered Al(111) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lugo, J.O.; Sanchez, E.A.; Grizzi, O. [Centro Atomico Bariloche - CNEA, CONICET, Instituto Balseiro - UNC, 8400 S.C. de Bariloche, Rio Negro (Argentina); Goldberg, E.C. [INTEC (CONICET-UNL), Gueemes 3450, cc 912, 3000 Santa Fe (Argentina); Facultad de Ingenieria Quimica, Univ. Nacional del Litoral, Santiago del Estero 2829, 3000 Santa Fe (Argentina)

    2004-08-01

    Ion Scattering Spectroscopy with Time-of-Flight analysis is used to characterize the deposition of thin insulating films (AlF{sub 3}) on Al(111) samples, and to measure the ion fractions for 20 keV H{sup +} projectiles scattered off clean and AlF{sub 3} covered Al(111) surfaces. The ion fraction measured for the clean surface is {proportional_to}12%, composed mainly of negative ions. For {proportional_to}2 ML of AlF{sub 3}, the ion fraction increases, being in this case mainly composed of positive ions ({gamma}{sup +}= 33%, {gamma}{sup -}= 3%). A calculation of the dynamical evolution of the collision and the resonant charge exchange processes describes the experimental trends. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Uncharted Frontiers in the Spectroscopy of Highly Charged Ions

    CERN Document Server

    Beiersdorfer, P; Crespo, J; Kim, S H; Neill, P; Utter, S; Widmann, K

    2000-01-01

    The development of novel techniques is critical for maintaining a state-of-the-art core competency in atomic physics and readiness for evolving programmatic needs. We have carried out a three-year effort to develop novel spectroscopic instrumentation that added new dimensions to our capabilities for measuring energy levels, radiative transition probabilities, and electron-ion excitation processes. The new capabilities created were in areas that heretofore had been inaccessible to scientific scrutiny and included high-resolution spectroscopy of hard x rays, femtosecond lifetime measurements, measurements of transition probabilities of long-lived metastable levels, polarization spectroscopy, ultra-precise determinations of energy levels, and the establishment of absolute wavelength standards in x-ray spectroscopy. Instrumentation developed during the period included a transmission-type crystal spectrometer, a flat-field EUV spectrometer, and the development and deployment of absolutely calibrated monolithic cry...

  4. Study of proton polarization in charge exchange process on optically oriented sodium atoms

    International Nuclear Information System (INIS)

    Using high-power adjustable dye lasers for electron spin orientation in a charge-exchange target enables to significantly increase the proton polarization efficiency. A device is described that permits to avoid growth of the polarized proton beam emittance in a charge-exchange process in a strong magnetic field. The devise main feature is the use of an intensive source of neutral hydrogen atoms and the presence of a helium additional charge-exchange target which actualy is a proton ''source''. The helium charge-exchange cell is placed in the same magnetic field of a solenoid where a cell with oriented sodium is placed, a polarized electron being captured by a proton in the latter cell. In this case the beam at the solenoid inlet and outlet is in a neutral state; emittance growth related to the effect of end magnetic fields is not observed. The device after all prouduces polarized protons, their polarization degree is measured and the effect of various factors on polarization degree is studied. The description of the laser source and laser system is given. Measurement results have shown the beam intensity of neutral 7 keV atoms which passed through a polarizer to be 2 mA. The proton current doesn't depend. On the beeld fin the region of chrge exchange for the 8 kGs magnetic field. The degree of sodium polarization was 80% and polarized proton current approximately 70 μA at a temperature of the polarized sodium cell corresponding to the density of sodium vapar approximately 3x1013 at/cm2

  5. A discussion of contributions to the 0νββ decay from the pion-charge-exchange mechanisms

    International Nuclear Information System (INIS)

    The contributions to the amplitude of the 0νββ decay, mediated by the heavy neutrino, from the two kinds of pion-charge-exchange mechanisms were discussed. The point-double-exchange mechanism is much more important for the 0 νββ decay in nuclei, compared to the point-single-exchange mechanism

  6. A hybrid charge sensitive preamplifier for nuclear spectroscopy applications

    International Nuclear Information System (INIS)

    An indigenous hybrid based preamplifier has been designed and developed successfully in collaboration with BEL, Bangalore. These hybrids are commercially available from BEL, Bangalore with part name as BMC 1521. The hybrids provide flexibility of selecting input JFET, feedback resistor and feedback capacitor, thus making it useful for a wide range of nuclear spectroscopy applications. (author)

  7. ({sup 18}O,{sup 18}Ne) double charge-exchange with MAGNEX

    Energy Technology Data Exchange (ETDEWEB)

    Bondí, M.; Cappuzzello, F.; Nicolosi, D.; Tropea, S. [Dipartimento di Fisica e Astrofisica, Universitá degli studi di Catania, Catania, 95100, Italy and Istituto di Fisica Nucleare - Laboratori Nazionali del Sud, Catania, 95100 (Italy); Agodi, C.; Carbone, D.; Cavallaro, M.; Cunsolo, A. [Istituto di Fisica Nucleare - Laboratori Nazionali del Sud, Catania, 95100 (Italy); De Napoli, M.; Foti, A. [Istituto di Fisica Nucleare - Sezione di Catania, Catania, 95100 (Italy)

    2014-05-09

    An experimental study concerning Double Gamow-Teller (DGT) modes in ({sup 18}O,{sup 18}Ne) Double Charge-Exchange reactions has been very recently performed at INFN-LNS laboratory in Catania. The experiment was performed using a {sup 40}Ca solid target and a {sup 18}O Cyclotron beam at 270 MeV incident energy. Charged ejectiles produced in the reaction were momentum analyzed and identified by MAGNEX spectrometer at very forward angles. Preliminary results are presented in the present paper.

  8. Charge-Exchange Neutral Particle Analyzer Diagnostic of TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Fontdecaba, J. M.; Balbin, R.; Petrov, S.; TJ-II team

    2003-07-01

    A description of the Charge Exchange Neutral Particle Analyzers in operation in the heliac flexible TJ-II is reported. A description of the detectors, as well as the operation characteristics, hardware and software used in the control and analysis of the data obtained with the diagnostic is detailed. Two NPAs are in operation in TJ-II. One of them is a 5-channel analyzer and another one is an Acord-12. The 5-channel analyzer provides measurements of charge exchange neutral fluxes at five energy channels, whereas the Acord-12 can measure simultaneously two different hydrogen isotopes (H and D) at six energy channels. Their lines of sight can be varied poloidally in order to observe the different sections of the plasma. (Author) 10 refs.

  9. Low-energy pion double charge exchange and nucleon-nucleon correlations in nuclei

    International Nuclear Information System (INIS)

    Recent measurements of pion double-charge exchange (DCX) at energies 20 to 70 MeV are providing a new means for studying nucleon-nucleon correlations in nuclei. At these energies the nucleus is relatively transparent, allowing simpler theoretical models to be used in interpreting the data and leading to a clearer picture. Also the contribution to DCX of sequential charge-exchange scattering through the intermediate analog state is suppressed near 50 MeV and transitions through non-analog intermediate states become very important. Recent theoretical studies by several groups have shown that while transitions through the analog route involve relatively long nucleon-nucleon distances, those through non-analog intermediate states obtain nearly half their strength from nucleon pairs with less than 1 fermi separation. Thus DCX near 50 MeV is an excellent way to study short-range nucleon-nucleon correlations. 31 refs., 29 figs., 4 tabs

  10. Progress in the pellet charge exchange diagnostics on LHD and local neutral particle spectra analysis

    International Nuclear Information System (INIS)

    Production, confinement and thermalization of high-energy particles are the fundamental issues in fusion plasma ion kinetics. The ion distribution function ft(ν, θ, t) and its evolution under the ion cyclotron heating (ICH) and neutral beam injection (NBI) are studied by energy resolved charge exchange neutral particle flux measurements. For helical systems, such as LHD, local diagnostics are required due to the complex 3D magnetic configuration. First radially resolved measurements of local H0 atomic energy spectra have been made on LHD by the pellet charge exchange (PCX) method with a Compact Neutral Particle Analyzer (CNPA). The diagnostic technique, the initial measurement results in the range 10-100 keV and the data analysis are described. (author)

  11. Core polarization phenomena in pion-nucleus charge-exchange reactions above the delta resonance

    International Nuclear Information System (INIS)

    We study pion-induced single- and double-charge exchange reactions in nuclei at energies above the Δ(3/2,3/2) resonance using a microscopic, parameter-free Glauber approach. We introduce corrections in the amplitudes due to the medium polarization from an isospin-flip spin-nonflip source which dominates the reaction in the transitions studied and which has not previously been identified. Using an effective force derived from the study of electromagnetic transitions we obtain sizable reductions of the cross sections in both single- and double-charge exchanges, which bring the results of both reactions into close agreement with experiment. Predictions for angular distributions for both reactions on 14C, 18O, and 42Ca targets are made which should serve as guidelines for experiments planned in this region and as further tests of the proposed isovector renormalization

  12. Influence of resonant charge exchange on the viscosity of partially ionized plasma in a magnetic field

    International Nuclear Information System (INIS)

    The influence of resonant charge exchange for ion-atom interaction on the viscosity of partially ionized plasma embedded in the magnetic field is investigated. The general system of equations used to derive the viscosity coefficients for an arbitrary plasma component in the 21-moment approximation of Grad’s method is presented. The expressions for the coefficients of total and partial viscosities of a multicomponent partially ionized plasma in the magnetic field are obtained. As an example, the coefficients of the parallel and transverse viscosities for the ionic and neutral components of the partially ionized hydrogen plasma are calculated. It is shown that the account for resonant charge exchange can lead to a substantial change of the parallel and transverse viscosity of the plasma components in the region of low degrees of ionization on the order of 0.1

  13. Charge exchange contamination of CRIT-II barium CIV experiment. [critical ionization velocity in ionosphere

    Science.gov (United States)

    Swenson, G. R.; Mende, S. B.; Meyerott, R. E.; Rairden, R. L.

    1991-01-01

    Experiments have been recently performed which attempted to confirm critical ionization velocity (CIV) ionization by deploying chemicals at high velocity in the ionosphere. Specifically, the CRIT-II rocket performed a barium release in the ionosphere, where observations of Ba(+) resonant emissions following the release are believed to have resulted from the CIV process. Calculations are presented which suggest a significant fraction (if not all) of the Ba(+) observed likely resulted from charge exchange with the thermosphere ions and not through CIV processes. The results presented here are pertinent to other CIV experiments performed in the ionosphere. It is recommended that laboratory measurements should be made of the charge exchange cross section between O(+) and Ba as well as other metal vapors used in CIV experiments.

  14. Solar wind/local interstellar medium interaction including charge exchange with neural hydrogen

    Science.gov (United States)

    Pauls, H. Louis; Zank, Gary P.

    1995-01-01

    We present results from a hydrodynamic model of the interaction of the solar wind with the local interstellar medium (LISM), self-consistently taking into account the effects of charge exchange between the plasma component and the interstellar neutrals. The simulation is fully time dependent, and is carried out in two or three dimensions, depending on whether the helio-latitudinal dependence of the solar wind speed and number density (both giving rise to three dimensional effects) are included. As a first approximation it is assumed that the neutral component of the flow can be described by a single, isotropic fluid. Clearly, this is not the actual situation, since charge exchange with the supersonic solar wind plasma in the region of the nose results in a 'second' neutral fluid propagating in the opposite direction as that of the LISM neutrals.

  15. Solar Wind Charge Exchange X-ray Emission from Earth's Magnetosheath

    Science.gov (United States)

    Snowden, Steve L.; Kuntz, K. D.

    2016-04-01

    The magnetospheric component of solar wind charge-exchange (SWCX) emission is primarily due to interaction between the high-state ions in the solar wind and the hydrogen in the outermost part of the Earth’s atmosphere. This emission was the primary source of the ROSAT long-term enhancements (LTEs). Using the correlation between the LTEs and the solar wind flux as well as a dynamic models of the magnetosheath, we have derived the 1/4 keV broad-band charge-exchange cross-section, and can show that this method can not be directly applied to the 3/4 keV band. I will discuss the uncertainties in this method and the prospects for improvement.

  16. Analysing powers and spin correlations in deuteron–proton charge exchange at 726 MeV

    Directory of Open Access Journals (Sweden)

    S. Dymov

    2015-05-01

    Full Text Available The charge exchange of vector polarised deuterons on a polarised hydrogen target has been studied in a high statistics experiment at the COSY-ANKE facility at a deuteron beam energy of Td=726 MeV. By selecting two fast protons at low relative energy Epp, the measured analysing powers and spin correlations are sensitive to interference terms between specific neutron–proton charge-exchange amplitudes at a neutron kinetic energy of Tn≈12Td=363 MeV. An impulse approximation calculation, which takes into account corrections due to the angular distribution in the diproton, describes reasonably the dependence of the data on both Epp and the momentum transfer. This lends broad support to the current neutron–proton partial wave solution that was used in the estimation.

  17. Analysing powers and spin correlations in deuteron-proton charge exchange at 726 MeV

    CERN Document Server

    Dymov, S; Bagdasarian, Z; Barsov, S; Carbonell, J; Chiladze, D; Engels, R; Gebel, R; Grigoryev, K; Hartmann, M; Kacharava, A; Khoukaz, A; Komarov, V; Kulessa, P; Kulikov, A; Kurbatov, V; Lomidze, N; Lorentz, B; Macharashvili, G; Mchedlishvili, D; Merzliakov, S; Mielke, M; Mikirtychyants, M; Mikirtychyants, S; Nioradze, M; Ohm, H; Prasuhn, D; Rathmann, F; Serdyuk, V; Seyfarth, H; Shmakova, V; Ströher, H; Tabidze, M; Trusov, S; Tsirkov, D; Uzikov, Yu; Valdau, Yu; Weidemann, C; Wilkin, C

    2015-01-01

    The charge exchange of vector polarised deuterons on a polarised hydrogen target has been studied in a high statistics experiment at the COSY-ANKE facility at a deuteron beam energy of Td = 726 MeV. By selecting two fast protons at low relative energy E_{pp}, the measured analysing powers and spin correlations are sensitive to interference terms between specific neutron-proton charge-exchange amplitudes at a neutron kinetic energy of Tn ~ 1/2 Td =363 MeV. An impulse approximation calculation, which takes into account corrections due to the angular distribution in the diproton, describes reasonably the dependence of the data on both E_{pp} and the momentum transfer. This lends broad support to the current neutron-proton partial-wave solution that was used in the estimation.

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

    CERN Document Server

    Bertulani, C A

    2015-01-01

    Indirect methods using nucleus-nucleus reactions at high energies (here, high energies mean $\\sim$ 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.

  19. ROSAT Observations of Solar Wind Charge Exchange with the Lunar Exosphere

    Science.gov (United States)

    Collier, Michael R.; Snowden, S. L.; Benna, M.; Carter, J. A.; Cravens, T. E.; Hills, H. Kent; Hodges, R. R.; Kuntz, K. D.; Porter, F. Scott; Read, A.; Robertson, I. P.; Sembay, S. F.; Sibeck, D. G.; Stubbs, Timothy J.; Travnicek, P.

    2012-01-01

    We analyze the ROSAT PSPC soft X-ray image of the Moon taken on 29 June 1990 by examining the radial profile of the count rate in three wedges, two wedges (one north and one south) 13-32 degrees off (19 degrees wide) the terminator towards the dark side and one wedge 38 degrees wide centered on the anti-solar direction. The radial profiles of both the north and the south wedges show substantial limb brightening that is absent in the 38 degree wide antisolar wedge. An analysis of the count rate increase associated with the limb brightening shows that its magnitude is consistent with that expected due to solar wind charge exchange (SWCX) with the tenuous lunar atmosphere. Along with Mars, Venus, and Earth, the Moon represents another solar system body at which solar wind charge exchange has been observed. This technique can be used to explore the solar wind-lunar interaction.

  20. Low-energy pion double charge exchange and nucleon-nucleon correlations in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leitch, M.J.

    1989-01-01

    Recent measurements of pion double-charge exchange (DCX) at energies 20 to 70 MeV are providing a new means for studying nucleon-nucleon correlations in nuclei. At these energies the nucleus is relatively transparent, allowing simpler theoretical models to be used in interpreting the data and leading to a clearer picture. Also the contribution to DCX of sequential charge-exchange scattering through the intermediate analog state is suppressed near 50 MeV and transitions through non-analog intermediate states become very important. Recent theoretical studies by several groups have shown that while transitions through the analog route involve relatively long nucleon-nucleon distances, those through non-analog intermediate states obtain nearly half their strength from nucleon pairs with less than 1 fermi separation. Thus DCX near 50 MeV is an excellent way to study short-range nucleon-nucleon correlations. 31 refs., 29 figs., 4 tabs.

  1. What can we learn from A(π+, η)B charge exchange reaction?

    International Nuclear Information System (INIS)

    Within DWIA formalism, the η production cross sections from nuclear target by charge exchange reaction A(π+, η)B are calculated. For 13C target the cross sections at forward angles are of the order of 10 μb/sr at Tπ = 660 MeV, which can be measured experimentally. The high momentum component of the wave function of single particle bound state is essential for describing this reaction

  2. Charge-exchange excitations with finite range interactions including tensor terms

    CERN Document Server

    De Donno, V; Anguiano, M; Lallena, A M

    2014-01-01

    We study charge-exchange excitations in doubly magic-nuclei by using a self-consistent Hartree-Fock plus Random Phase Approximation model. We use four Gogny-like finite-range interactions, two of them containing tensor forces. We investigate the effects of the various parts of the tensor forces in the two computational steps of our model, and we find that their presence is not negligible and improves the agreement with the experimental data.

  3. A Schwinger-type variational principle for charge exchange at arbitrary energies

    International Nuclear Information System (INIS)

    An overview of difficulties encountered in charge exchange collision theory is presented. We emphasize problems in the most critical intermediate energy region where, as yet, no adequate method is available. A Schwinger-type variational principle, which is established at arbitrary energies, appears to exhibit many advantages over existing theories. It successfully connects the leading second Born approximation with the efficient L2-expansion methods. (orig.)

  4. Measurement of pion double charge exchange on carbon-13, carbon-14, magnesium-26, and iron-56

    International Nuclear Information System (INIS)

    Cross sections for the /sup 13,14/C,26Mg,56Fe(π+,π-)/sup 13,14/O,26Si,56Ni reactions were measured with the Energetic Pion Channel and Spectrometer at the Clinton P. Anderson Meson Physics Facility for 120 less than or equal to T/sub π/ less than or equal to 292 MeV and 0 less than or equal to theta less than or equal to 50. The double isobaric analog states (DIAS) are of primary interest. In addition, cross sections for transitions to 14O(0+, 5.92 MeV), 14O(2+, 7.77 MeV), 56Ni(gs), 13O(gs), and 13O(4.21 MeV) are presented. The 13O(4.21 MeV) state is postulated to have J/sup π/ = 1/2-. The data are compared to previously measured double-charge-exchange cross sections on other nuclei, and the systematics of double charge exchange on T greater than or equal to 1 target nuclei leading to the DIAS are studied. Near the Δ33 resonance, cross sections for the DIAS transitions are in disagreement with calculations in which the reaction is treated as sequential charge exchange through the free pion-nucleon amplitude, while for T/sub π/ > 200 MeV the anomalous features of the 164 MeV data are not apparent. This is evidence for significant higher order contributions to the double-charge-exchange amplitude near the reasonable energy. Two theoretical approaches that include two nucleon processes are applied to the DIAS data. 64 references

  5. Nuclear charge-exchange excitations in localized covariant density functional theory

    International Nuclear Information System (INIS)

    The recent progress in the studies of nuclear charge-exchange excitations with localized covariant density functional theory is briefly presented, by taking the fine structure of spin-dipole excitations in 16O as an example. It is shown that the constraints introduced by the Fock terms of the relativistic Hartree-Fock scheme into the particle-hole residual interactions are straightforward and robust. (authors)

  6. Charge-exchange emission in the starburst galaxies M82 and NGC3256

    CERN Document Server

    Ranalli, Piero

    2012-01-01

    Charge-exchange (CE) emission produces features which are detectable with the current X-ray instrumentation in the brightest near galaxies. We describe these aspects in the observed X-ray spectra of the star forming galaxies M82 and NGC 3256, from the Suzaku and XMM-Newton telescopes. Emission from both ions (O, C) and neutrals (Mg, Si) is recognised. We also describe how microcalorimeter instrumentation on future missions will improve CE observations.

  7. Nuclear charge-exchange excitations in localized covariant density functional theory

    CERN Document Server

    Liang, H Z; Nakatsukasa, T; Niu, Z M; Ring, P; Roca-Maza, X; Van Giai, N; Zhao, P W

    2014-01-01

    The recent progress in the studies of nuclear charge-exchange excitations with localized covariant density functional theory is briefly presented, by taking the fine structure of spin-dipole excitations in 16O as an example. It is shown that the constraints introduced by the Fock terms of the relativistic Hartree-Fock scheme into the particle-hole residual interactions are straightforward and robust.

  8. Production and decay of Δ'S in nuclei; emission of coherent pions in charge exchange

    International Nuclear Information System (INIS)

    The decay channels of the Δ resonance formed in nuclei, by the charge exchange reaction (3He,t) at 2 GeV, have been studied, on 2H, 4He, 12C and Pb targets, in exclusive experiments with the large acceptance detector Diogene. The quasi-free channel Δ++ -> p+ π+, the two proton decay channel and the single pion decay channel have been observed and investigated. The emission of coherent pions has been identified. (authors). 8 refs., 11 figs

  9. Kinetic treatment of the heavy ion charge exchange injection in synchrotrons

    CERN Document Server

    Dinev, D

    2002-01-01

    This paper describes the results of a kinetic treatment of the charge exchange injection of heavy ions into synchrotrons. Analytical expressions for the evolution of particle density in the transverse phase space and for the emittance growth due to elastic scattering and energy losses in the stripper have been derived. Numerical examples for the superconducting heavy ion synchrotron Nuclotron in JINR-Dubna are given as well.

  10. Charge-exchange scattering in K- p interactions below 300 MeV/c

    International Nuclear Information System (INIS)

    Cross sections for K-p charge exchange, based on new data equal in statistics to the sum of those of all previous determinations below 300 MeV/c, are presented. The results confirm an earlier observation by this collaboration that the previous measurements of these cross sections at low momentum were significantly underestimated. Evidence for the presence of P wave scattering is presented. (author)

  11. Coherent control of charge exchange in strong-field dissociation of LiF

    Science.gov (United States)

    Armstrong, Greg; Esry, Brett

    2016-05-01

    The alkali-metal-halides family of molecules are useful prototypes in the study of laser-assisted charge exchange. Typically these molecules possess a field-free crossing between the ionic and covalent diabatic Born-Oppenheimer potential curves, leading to Li+ + F- and Li + F in LiF. These channels are energetically well-separated from higher-lying potentials, and may be easily distinguished experimentally. Moreover, charge exchange involves non-adiabatic transitions between the ionic and covalent channels, thereby allowing the investigation of physics beyond the Born-Oppenheimer approximation. The focus of this work is to control the preference between ionic and covalent dissociative products. We solve the time-dependent Schrödinger equation for the nuclear motion in full dimensionality, and investigate a pump-probe scheme for charge-exchange control. The degree of control is investigated by calculating the kinetic-energy release spectrum as a function of pump-probe delay for the ionic and covalent fragments. This work is supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy.

  12. Modeling the Hydrogen-Proton Charge-Exchange Process in Global Heliospheric Simulations

    Science.gov (United States)

    DeStefano, A.; Heerikhuisen, J.

    2015-12-01

    The environment surrounding our Solar System has a vast and dynamic structure. As the Sun rounds the Milky Way galaxy, interstellar dust and gas interact with the Sun's outflow of solar wind. A bubble of hot plasma forms around the Sun due to this interaction, called the heliosphere. In order to understand the structure of the heliosphere, observations and simulations must work in tandem. Within the past decade or so, 3D models of the heliosphere have been developed exhibiting non- symmmetric as well as predicting structures such as the hydrogen wall and the IBEX ribbon. In this poster we explore new ways to compute charge-exchange source terms. The charge-exchange process is the coupling mechanism between the MHD and kinetic theories. The understanding of this process is crucial in order to make valuable predictions. Energy dependant cross section terms will aid in settling non-linear affects coupling the intestellar and solar particles. Through these new ways of computing source terms, resolving fine structures in the plasma in the heliopause may be possible. In addition, other non-trivial situations, such as charge-exchange mediated shocks, may be addressed.

  13. X-ray Emission Measurements following Charge Exchange between C6+ and He

    Energy Technology Data Exchange (ETDEWEB)

    Defay, X [University of Wisconsin, Madison; Morgan, K [University of Wisconsin, Madison; McCammon, D [University of Wisconsin, Madison; Wulf, D. [University of Wisconsin, Madison; Andrianarijaona, V. M. [Pacific Union College; Fogle, Jr., M R, [Auburn University, Auburn, Alabama; Seely, D. G. [Albion College; Draganic, Ilija N [ORNL; Havener, Charles C [ORNL

    2013-01-01

    X-ray spectra following charge exchange collisions between C6+ and He are presented for collision energies between 460 eV/u and 32,000 eV/u. Spectra were obtained at the Oak Ridge National Laboratory ion-atom merged-beams apparatus, using a microcalorimeter X-ray detector capable of fully resolving the C VI Lyman series lines through Ly-gamma. These line ratios are sensitive to the initial electron