Proton Emission Research Articles

Controlling directional emission of ions attached on the surface of nanoparticles

Abstract The interaction between lasers and nanoparticles holds significant theoretical and practical importance. Here, we investigate the near-field enhancement effects on silver nanotriangles and nanodiscs under ultrafast laser pulses, as well as the dynamics of protons and ions attached to the nanoparticle surfaces. By adjusting the size parameters of the nanoparticles, we explore the near-field enhancement effects and proton emission dynamics at different laser wavelengths. The results demonstrate that nanoparticles with varying morphologies substantially impact the proton momentum spectrum. The directional proton emission of nanotriangle structures is more pronounced compared to that of nanodiscs, and this effect can be further enhanced by adjusting the laser wavelength. Additionally, manipulating the thickness of particles also controls the Mie scattering phenomenon of light. Finally, we qualitatively discuss the emission processes of alpha particles and 9C6+ heavy ions. This research has important implications for proton and heavy ion radiotherapy in cancer treatment and targeted drug delivery, while providing theoretical foundations for understanding, characterizing, and controlling experimental studies of nanosystems with significant potential for expanding research into microdynamic behavior in complex nanomaterial superstructures.

Prompt Emission of Relativistic Protons up to GeV Energies from M6.4-Class Solar Flare on July 17, 2023

Prompt Emission of Relativistic Protons up to GeV Energies from M6.4-Class Solar Flare on July 17, 2023

Description of the emission of cumulative secondary particles in collisions of heavy ions of intermediate energies based on the non-equilibrium hydrodynamic approach

We have analyzed the double-differential cross sections for the emission of cumulative protons, pions, kaons, and antiprotons in collisions of carbon nuclei on a fixed target at an energy of 19.6 GeV/nucleon obtained in the IHEP experiment at the U-70 accelerator. When describing these spectra, the nonequilibrium approach was taken into account as a result of the joint solution of the kinetic equation with the equations of hydrodynamics. Comparisons with other approaches are made.

Decay study of Be11 with an optical time-projection chamber

The β decay of one-neutron halo nucleus Be11 was investigated using the Warsaw Optical Time Projection Chamber (OTPC) detector to measure β-delayed charged particles. The results of two experiments are reported. In the first one, carried out in LNS Catania, the absolute branching ratio for β-delayed α emission was measured by counting incoming Be11 ions stopped in the detector and the observed decays with the emission of α particle. The result of 3.27(46)% is in good agreement with the literature value. In the second experiment, performed at the HIE-ISOLDE facility at CERN, bunches containing several hundreds of Be11 ions were implanted into the OTPC detector followed by the detection of decays with the emission of charged particles. The energy spectrum of β-delayed α particles was determined in the full energy range. It was analyzed in the R-matrix framework and was found to be consistent with the literature. The best description of the spectrum was obtained assuming that the two 3/2+ and one 1/2+ states in B11 are involved in the transition. The search for β-delayed emission of protons was undertaken. Only the upper limit for the branching ratio for this process of (2.2±0.6stat±0.6sys)×10−6 could be determined. This value is in conflict with the result published by Ayyad [] but does agree with the limit reported by Riisager []. Published by the American Physical Society 2024

Three-body deprotonation fragmentation dynamics of C6H63+ induced by electron-impact ionization.

The three-body fragmentation dynamics of benzene trications C6H63+ induced by 200eV electron-impact produced by a photoemission cathode is investigated. All three fragment ions are detected in coincidence, and their momentum vectors are determined by employing a COLTRIMS reaction microscope. The detailed kinematical information of three deprotonation fragmentation channels of H+ + C3H2+ + C3H3+, H+ + C2H3+ + C4H2+, and H+ + C2H2+ + C4H3+ are obtained. By analyzing the momentum and energy correlation spectra among all the three fragment ions, we find that all the three channels are primarily generated by sequential fragmentation processes. Each channel has two deprotonation pathways, corresponding to proton emission in the first or second step of sequential fragmentation, respectively. These results provide insight into the mechanisms and dynamics of deprotonation and ring-breaking reactions in the three-body fragmentation processes of aromatic ring molecules.

Observation of near-scission “polar” and “equatorial” proton emission in heavy-ion induced fission

Proton and α-particle energy spectra were measured in coincidence with fission fragments at different relative angles in 16O (96 MeV) + 232Th reaction. The multiplicity spectra were analyzed within the framework of a Moving Source Disentangling Analysis (MSDA) to determine contributions from different emission stages. The MSDA conclusively shows “Near Scission Emission (NSE)” as an essential component in the multiplicity spectra. In contrast to NSE α particles which emit mainly perpendicular (“equatorial emission”), the NSE protons are observed to be emitted perpendicular as well as parallel (“polar emission”) to the fission axis with similar intensities (~20% for each). Thus, around 40% of total pre-scission protons are emitted near the scission stage, whereas the same fraction for α particles is only around 10%. The inevitable presence of “polar” and “equatorial” NSE protons in a heavy-ion induced fission has been observed for the first time. Present results open up a new avenue to study the heavy-ion induced fission dynamics.

Unified insights: Relativistic density functional theory for proton resonance, emission, and proton-rich exotic nuclei

Unified insights: Relativistic density functional theory for proton resonance, emission, and proton-rich exotic nuclei

Detailed study of the decay of 21\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{21}$$\\end{document}Mg

Beta-delayed proton and gamma emission in the decay of 21\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{21}$$\\end{document}Mg has been measured at ISOLDE, CERN with the ISOLDE Decay Station (IDS) set-up. The existing decay scheme is updated, in particular what concerns proton transitions to excited states in 20\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{20}$$\\end{document}Ne. Signatures of interference in several parts of the spectrum are used to settle spin and parity assignments to highly excited states in 21\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{21}$$\\end{document}Na. The previously reported β\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta $$\\end{document}pα\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\alpha $$\\end{document} branch is confirmed. A half-life of 120.5(4) ms is extracted for 21\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{21}$$\\end{document}Mg. The revised decay scheme is employed to test mirror symmetry in the decay and to extract the beta strength distribution of 21\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{21}$$\\end{document}Mg that is compared with theory.

Study α decay and proton emission based on data-driven symbolic regression

α decay and proton emission were combined using symbolic regression to improve the accuracy of predicting their respective half-lives using two theoretical formulations: (1) adjustable parameters for the universal decay law and universal decay law for proton emission are obtained by regressions with fully-constrained symbolic regressions. (2) New theoretical formulas for calculating the half-life of proton emission and α decay are obtained using unconstrained symbolic regressions combined with nuclear data. Our computational analysis indicates that fully-constrained symbolic regressions and unconstrained symbolic regressions are reliable for specific and general nuclei, respectively, in terms of replicating experimental results, and are sufficiently robust to produce accurate half-life predictions. Unlike other machine learning methods that generate complex and opaque results, our approach integrates physics and machine learning to create interpretable formulas that provide intuitive parametric outcomes and transparent and dependable inferences of half-lives, even in areas with limited experimental data. The test results show that the equation yields accurate results, and can be easily applied to future α decay and proton emission studies.

All-optical steering on the proton emission in laser-induced nanoplasmas

Nanoplasmas induced by intense laser fields have attracted enormous attention due to their accompanied spectacular physical phenomena which are vigorously expected by the community of science and industry. For instance, the energetic electrons and ions produced in laser-driven nanoplasmas are significant for the development of compact beam sources. Nevertheless, effective confinement on the propagating charged particles, which was realized through magnetic field modulation and target structure design in big facilities, are largely absent in the microscopic regime. Here we introduce a reliable scheme to provide control on the emission direction of protons generated from surface ionization in gold nanoparticles driven by intense femtosecond laser fields. The ionization level of the nanosystem provides us a knob to manipulate the characteristics of the collective proton emission. The most probable emission direction can be precisely steered by tuning the excitation strength of the laser pulses. This work opens new avenue for controlling the ion emission in nanoplasmas and can vigorously promote the fields such as development of on-chip beam sources at micro-/nano-scales.

Competition of proton radioactivity with α- and β+-decays

Competition of proton radioactivity with α- and β+-decays

Possible 2p Decay Emission in the Region 4 ≤ Z ≤ 54 Using the Modified CYE Model

Two proton radioactivity is the spontaneous emission of two protons simultaneously from the nucleus. We have extended our CYE model to study this 2p radioactivity. The current work aims to study the 2p radioactivity of nuclei between Z ≥ 4 to Z ≤ 54 . Moreover, the impact of a deformation of the nucleus is also examined. To comprehend two-proton decay, numerous theoretical works have been developed. The half lifetimes for 2p decays calculated using this CYE model are in a good accord with CPPMDN model of K.P. Santhosh, GLDM, ELDM, GLM, Sreeja et al. and Liu et al. and SEB, SHF and UFM. From whence, it appears that the CYE model is a reasonable choice for assessing 2p radioactivity.

Exploring the competition between α-decay and proton radioactivity: A comparative study of proximity potential formalisms

We have conducted a comprehensive and systematic study of the proton radioactivity and α-decay half-lives of neutron-deficient nuclei. This investigation involved the utilization of various Proximity potentials and also considered the incorporation of thermal effects. For the half-life calculations, we employed both temperature-independent and temperature-dependent interaction potentials. We observed that proton radioactivity serves as the dominant mode of decay for nuclides situated very close to the proton drip-line. We explored a universal curve that examines the correlation between the decimal logarithm of experimental half-lives and the negative decimal logarithm of the penetrability for both proton radioactivity and α-decay.

Calculation of the half-life of proton radioactivity using the empirical formula depending on angular momentum

In this paper, considering the power of the daughter nuclear charge as a function of the orbital angular momentum taken away by the emitted proton, we propose a formula for the half-life of proton radioactivity. In this formula, we have three coefficients with orbital angular momentum dependence. Using experimentally measured half-lives for 8 proton emitters with [Formula: see text], 14 proton emitters with [Formula: see text] and 18 proton emitters with [Formula: see text], we have obtained the coefficients. The root mean square deviations of our formula respect to the experimental value are found 0.2514, 0.4442 and 0.1846 for emitters [Formula: see text], 2 and 5, respectively. We have compared our results with Sreeja formula, the semiempirical relation of Hatsukawa and theoretical models such as the Coulomb and proximity potential model (CPPM) and the Gamow-like model. The better agreement with experimental data was observed for our formula in comparison with other theoretical models and Sreeja and Hatsukawa formulas.

Photonically Projected Atoms: A Paradigm Shift in Atomic Physics

This paper presents the discovery of photonically projected atoms, first observed serendipitously during the development of a smartphone-based technique for material identification through reflected light measurements. Upon illuminating samples with ≥75,000 lumen from a light-emitting diode, we observed exact atomic projections emanating from charged particles within the sample. Analysis determined that protons within each atom bond with and re-emit contacted photons. After proton emission, a spatial lensing effect enlarges the projections of the photons to a diameter of 0.5 mm when measured 1 mm from the surface. The smaller 1⁄3” sensors and pixel size of smartphone cameras provide a better resolution of the fine structural details compared with larger digital camera alternatives. Through seven years of imaging analysis under various conditions, fundamental insights emerged on atomic architectures, particle interactions, and the role of space, empirically revising mainstream quantum theory. This research aims to disseminate recent advancements in the direct visualization and updated modeling of atomic projections to enable ongoing physics discoveries through this accessible technique.

Systematic study of two proton radioactivity within the effective liquid drop model

In this study, we investigated two-proton radioactivity using the effective liquid drop model with varying mass asymmetry shapes and effective inertia coefficients (VMAS-EFF). Gaudin’s expression term for Coulomb potential energy is replaced in the current study’s calculation of potential energy. The VMAS-EFF combination predicts the half-life with the lowest standard deviation ( σ =1.03) compared to other models and previous constant mass asymmetry with Werner-inertial Wheeler’s coefficient combinations. The lowest standard deviation value indicates that the VMAS-EFF combination is suitable for reproducing the experimental data. We extended the half-life predictions to another 54 nuclei and compared them with six theoretical model predictions and two empirical formula predictions. The present work also investigated the decay possibilities using quantum tunnelling by computing the driving potential (V-Q) for various states of angular momentum l = 0, 2, 3, and 4. Found that 6Be, 6B, 8C, 12O,15,16Ne, 19Mg, 22Si, 26S, 30Ar 38,39Ti, 40V, 42Cr, 45Fe, 48,49Ni, 54Zn, 58,59,60Ge and 64Se nuclei have a high chance of emission for two protons, while 7B, 10N, 14F, 17Na, 24P, 28Cl,32K, 34Ca, 36,37Sc, 44Mn, 47Co, 52Cu, 56,57,58Ga, 61,62As nuclei have a lower chance for two proton than one proton decay. The computation of separation energy findings agree well with the driving potential findings.

Systematic study of cluster radioactivity in trans-lead nuclei with various versions of proximity potential formalisms* *Supported in part by the National Natural Science Foundation of China (12175100, 11975132), the construct program of the key discipline in Hunan province, the Research Foundation of Education Bureau of Hunan Province, China (18A237, 22A0305), Hunan Provincial Department of Education Scientific Research Project (19A440), the

In this study, based on the framework of the Coulomb and proximity potential model (CPPM), we systematically investigate the cluster radioactivity half-lives of 26 trans-lead nuclei by considering the cluster preformation probability, which possesses a simple mass dependence on the emitted cluster according to R. Blendowske and H. Walliser [Phys. Rev. Lett. 61, 1930 (1988)]. Moreover, we investigate 28 different versions of the proximity potential formalisms, which are the most complete known proximity potential formalisms proposed to describe proton radioactivity, two-proton radioactivity, α decay, heavy-ion radioactivity, quasi-elastic scattering, fusion reactions, and other applications. The calculated results show that the modified forms of proximity potential 1977, denoted as Prox.77-12, and proximity potential 1981, denoted as Prox.81, are the most appropriate proximity potential formalisms for the study of cluster radioactivity, as the root-mean-square deviation between experimental data and relevant theoretical results obtained is the least; both values are 0.681. For comparison, the universal decay law (UDL) proposed by Qi et al. [Phys. Rev. C 80, 044326 (2009)], unified formula of half-lives for α decay and cluster radioactivity proposed by Ni et al. [Phys. Rev. C 78, 044310 (2008)], and scaling law (SL) in cluster radioactivity proposed by Horoi et al. [J. Phys. G 30, 945 (2004)] are also used. In addition, utilizing CPPM with Prox.77-12, Prox.77-1, Prox.77-2, and Prox.81, we predict the half-lives of 51 potential cluster radioactive candidates whose cluster radioactivity is energetically allowed or observed but not yet quantified in NUBASE2020. The predicted results are in the same order of magnitude as those obtained using the compared semi-empirical and/or empirical formulae. At the same time, the competition between α decay and cluster radioactivity of these predicted nuclei is discussed. By comparing the half-lives, this study reveals that α decay predominates.

Theoretical calculations of proton emission half-lives based on a deformed Gamow-like model* *Supported in part by the National Natural Science Foundation of China (12175100, 11975132), the Construct Program of the Key Discipline in Hunan Province, the Research Foundation of Education Bureau of Hunan Province, China (21B0402, 18A237), the Natural Science Foundation of Hunan Province, China (2018JJ2321), the Innovation Group of

In this study, proton emission half-lives were investigated for deformed proton emitters with based on the presented deformed Gamow-like model, where the deformation effect was included in the Coulomb potential. The experimental half-lives of proton emitters can be reproduced within a factor of 3.45. For comparison, the results from the universal decay law and the new Geiger-Nuttall law are also presented. Furthermore, the relevance of the half-lives to the angular momentum l for 117La, 121Pr, 135Tb, and 141Ho were analyzed, and the corresponding possible values of l were proposed: l = 3, 3, 4, 4.

Double differential cross section calculations of (n,p) reactions on 27Al and 24Mg targets

In structural fusion material research, double differential sections are necessary to determine heating and damage due to secondary particles that may occur in structural materials. Therefore, in this study, the double differential proton emission cross sections of 27Al and 24Mg target nuclei were calculated theoretically with the TALYS nuclear reaction code at 14 MeV neutron energy. The calculated values were compared with existing experimental data in the EXFOR library. Additionally, the contribution of direct, compound and preequilibrium reactions in theoretical calculations was investigated.

Description of the Proton-Decaying 0_{2}^{+} Resonance of the α Particle.

The recent precise experimental determination of the monopole transition form factor from the ground state of ^{4}He to its 0_{2}^{+} resonance via electron scattering has reinvigorated discussions about the nature of this first excited state of the α particle. The 0_{2}^{+} state has been traditionally interpreted in the literature as the isoscalar monopole resonance (breathing mode) or, alternatively, as a particle-hole shell-model excitation. To better understand the nature of this state, which lies only ∼410 keV above the proton emission threshold, we employ the coupled-channel representation of the no-core Gamow shell model. By considering the [^{3}H+p], [^{3}He+n], and [^{2}H+^{2}H] reaction channels, we explain the excitation energy and monopole form factor of the 0_{2}^{+} state. We argue that the continuum coupling strongly impacts the nature of this state, which carries characteristics of the proton decay threshold.