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The theory of Double Charge Exchange (DCX) reactions between nuclei requires both the description of the reaction mechanism, which consists of the exchange of nucleons between the target and the projectile, as well as the structure of the matrix elements of the operators which mediate the transitions. From the point of view of the nuclear structure theory it requires the use of microscopic models for light and heavy mass nuclei. The reaction sector requires the use of momentum-dependent operators. It has been argued that these matrix elements could be associated to decay channels like the neutrinoless nuclear double beta decay (0 νββ )(DBD). The motivation related to this claim is the need to determine, as accurately as possible, the values of the matrix elements of operators responsible for 0 νββ . We shall focus the attention on the possible relationship between DBD and DCX nuclear matrix elements, by studying the dependence of the participant operators upon the momentum.

Within the two-channel distorted wave second-order perturbative theoretical formalism, we study capture of both electrons from helium-like targets by heavy nuclei as projectiles at intermediate and high impact energies. The emphasis is on the four-body single-double scattering (SDS-4B) method and the three-body continuum distorted wave impact parameter method (CDW-3B-IPM). The SDS-4B method deals with the full quantum-mechanical correlative dynamics of all the four interactively participating particles (two electrons, two nuclei). The CDW-3B-IPM is a semi-classical three-body independent particle model (one electron, two nuclei), using a combinatorial calculus to describe double capture by a product of two uncorrelated probabilities, integrated over impact parameters. Both theories share a common feature in having altogether two electronic full Coulomb continuum wave functions. One such function is centered on the projectile nucleus in the entrance channel, whereas the other is centered on the target nucleus in the exit channel. These two methods satisfy the correct initial and final Coulomb boundary conditions in the asymptotic region of scattering, at infinitely large inter-particle separations. Yet, it is presently demonstrated that most of the available experimental data on total cross sections for the double capture from helium by alpha particles distinctly favor the SDS-4B method. This is especially true at intermediate energies. Such energies are critically important in versatile applications under the general umbrella of ion transport in matter, including thermonuclear fusion (plasma physics) and ion therapy (medicine).

The spectra and global distributions of the X-ray emissions generated by the solar wind charge-exchange (SWCX) process in the terrestrial magnetosheath are investigated based on a global hybrid model and a global geocoronal hydrogen model. Solar wind O6+ ions, which are the primary charge state for oxygen ions in solar wind, are considered. The line emissivity of the charge-exchange-borne O5+ ions is calculated by the Spectral Analysis System for Astrophysical and Laboratory (SASAL). It is found that the emission lines from O5+ range from 105.607 to 118.291 eV with a strong line at 107.047 eV. We then simulate the magnetosheath X-ray emission intensity distributions with a virtual camera at two positions of the north pole and dusk at six stages during the passing of a perpendicular interplanetary shock combined with a tangential discontinuity structure through the Earth’s magnetosphere. During this process, the X-ray emission intensity increases with time, and the maximum value is 27.11 keV cm−2 s−1 sr−1 on the dayside, which is 4.5 times that before the solar wind structure reached the Earth. A clear shock structure can be seen in the magnetosheath and moves earthward. The maximum emission intensity seen at dusk is always higher than that seen at the north pole.

To develop technologies for the stable operation of electric propulsion systems, the effects of charge exchange (CEX) on the exhaust plume of a Hall thruster were studied using the particle-in-cell direct simulation Monte Carlo (PIC-DSMC) method. For the numerical analysis, an OpenFOAM-based code, pdFOAM, with a simple electron fluid model was employed. In an example problem using the D55 Hall thruster exhaust plume, the results showed good agreement with experimental measurements of the plasma potential. In the results, CEX effects enhanced Xe+ particle scattering near the thruster exit. However, due to the increase in the plasma potential with CEX effects, fewer Xe2+ particles were near the thruster exit with CEX effects than without CEX effects.

The results of modification of WC–Co samples by a pulsed beam of nitrogen ions (200–300 keV, 120 ns) with an energy density of 7–8 J/cm 2 are presented. It is shown that the change in the structure occurs in the near-surface layer with a thickness of 20–30 μm, which significantly exceeds the range of ions in the target (≈0.5 μm) and the depth of propagation of the thermal front during the pulse (≈1 μm). Various mechanisms of the long-range effect, namely, the formation of a shock wave, the generation of primary radiation defects, etc. are analyzed. It is shown that the long-range effect is associated with the charge exchange of ions and the formation of fast atoms. The simulation of the charge exchange of ions in the gaseous layer of desorbed molecules is performed. It is found that the probability of ion charge exchange in the processes N +  + N 2 → N 0 and N + + O 2 → N 0 significantly exceeds 100%, which indicates that the effect of irradiation of the target by fast atoms must be taken into account. In contrast to ions, when the target is irradiated with atoms, the efficiency of the formation of radiation defects is much higher.

We present a new method for coating deposition on micro cutters without an increase in their cutting edges radii caused by the deposition. For this purpose, the cutting edges are sharpened before the coating deposition with a concentrated beam of fast argon atoms. The sharpening decreases the initial radius and, hence, limits its value after the coating deposition. The concentrated beam of fast argon atoms is generated using an immersed in the gas discharge plasma concave grid under a negative high voltage. Ions accelerated from the plasma by the grid pass through the grid holes and are concentrated in the focal point of the grid. As a result of the charge exchange in the space charge sheaths of the grid, they are transformed into fast atoms. A uniform sputtering by the fast atoms of the micro-cutter surface reduces the radius of its cutting edge.

The Liège intranuclear-cascade model (INCL) has been improved using a refined description of the matter and energy densities in the nuclear surface. Hartree-Fock-Bogoliubov calculations with the Skyrme interaction were used to obtain a more realistic description of the proton and neutron density profiles. We find that the new approach, together with a realistic modeling of the de-excitation process of the nuclear pre-fragments, improves the description of the production cross sections of the heaviest nuclear residues produced by charge-exchange processes in spallation reactions, where the excitation of baryonic resonances plays an important role.

The G-NUMEN array is the future gamma spectrometer of the NUMEN experiment (nuclear matrix element for neutrinoless double beta decay), to be installed around the object point of the MAGNEX magnetic spectrometer at the INFN-LNS laboratory. This project aims to explore double-charge exchange (DCE) reactions in order to obtain crucial information about neutrinoless double beta decay (0νββ). The primary objective of the G-NUMEN array is to detect the gamma rays emitted from the de-excitation of the excited states that are populated via DCE reactions with a good energy resolution and detection efficiency, amidst a background composed of the transitions from competing reaction channels with far higher cross sections. To achieve this, G-NUMEN signals will be processed in coincidence with those generated by the detection of reaction ejectiles by the MAGNEX focal plane detector (FPD). Under the expected experimental conditions, G-NUMEN detectors will operate at high counting rates, of the order of hundreds of kHz per detector, while maintaining excellent energy and timing resolutions. The complete array will consist of over 100 LaBr3(Ce) scintillators. Initial tests were conducted on the first detectors of the array, allowing for the determination of their performance at high rates.

(1) Pions produced in the development of extended atmospheric cosmic ray air showers subsequently decay to muons. The measured yield of those muons is generally underestimated by current phenomenological models and event generators optimized for cosmic ray physics. The importance of those disagreements motivates the feasibility studies for testing these models at the Large Hadron Collider (LHC) energies, at the highest center-of-mass energies achievable in a laboratory. The interaction of a nucleus and a virtual pion created in a charge exchange reaction at the LHC is a similar process to those contributing to the development of air showers in case of cosmic rays. The crucial problem of such an analysis is the selection of charge exchange events with the highest possible efficiency and high purity from proton–proton collisions at the LHC. (2) For this we consider distributions of various measurable quantities given by event generators commonly used in cosmic ray physics. (3) We examine the expected distributions of energy deposited in different calorimeters of an LHC experiment. We consider the geometrical acceptance and energy resolution of the detectors at the Compact Muon Solenoid (CMS) experiment, as an example. We determine a working point cut from the various options for event selection, and compare signal and background predictions using different models for a representative simple observable, such as average transverse momentum or charge particle yield. (4) A set of event selection cuts along these considerations is proposed, with the aim of achieving optimal efficiency and purity.

The development and design of the CXRS diagnostic for the core plasma of ITER is used as a pretext to elaborate on several of the main challenges of optical diagnostics on such a large fusion device. The idea was to confront the students of the 16th Ettore Majorana School on Diagnostics and Technology Developments with as many aspects of the design of optical diagnostics as possible. After an elementary review of the basics of charge-exchange, of typical spectra, of intended measurements and of the expected associated background, the DNB (diagnostic neutral beam) is briefly presented. The light collection and transport to the ex-vessel fibres and spectrometers constitutes the main part of this contribution: building on existing telescope and endoscope systems, the choice of a suitable optical layout for the core-plasma CXRS diagnostic at ITER is discussed. An account follows of the protective measures against the degradation of the first mirror, which will be exposed to high particle and heat fluxes: an appropriate duct, a shutter and, possibly, a cleaning discharge with “End-of-Cleaning Indicator”.