Light Charged Particles Research Articles

THE VALUE AND THE SIGN ESTIMATION OF THE ROT EFFECT FOR 239,241Pu ISOTOPES DURING THEIR FISSION BY POLARIZED NEUTRONS IN THE RESONANT ENERGY REGION

It is proposed to measure the shift in the angular distribution of light charged particles (LCP) in ternary fission caused by polarized neutrons of plutonium isotopes in the resonance region with 𝐸𝑛 = 0.264 eV for the 241Pu target and 𝐸𝑛 = 0.294 eV for the 239Pu target. The reliability of interpretation of these experiments will compare favorably with measurements carried out previously at 𝐸𝑛 = 4.5 meV. The advantage is associated with a noticeable weakening of the influence of resonances, the parameters of which may raise some doubts. We are talking about resonances introduced at neutron energies 𝐸𝑛 < 0 eV. In addition, in the region of these two resonances, the fractions of impurity partial cross sections with a spin different from the spin of the resonance itself are small. It is important that the magnitude of the effects expected at the indicated resonance energies will be significantly greater than those previously obtained in the cold neutron energy region.

Study on the reaction channels in the 6Li+89Y system with multi-angular proton and deutron-γ coincidence analysis

Study on the reaction channels in the 6Li+89Y system with multi-angular proton and deutron-γ coincidence analysis

Experimental characterization of discrimination capabilities of EJ-276 and EJ-276G read by SiPM by pulse-shape analysis techniques

Experimental characterization of discrimination capabilities of EJ-276 and EJ-276G read by SiPM by pulse-shape analysis techniques

A comprehensive analysis of interaction with charged particles of Rene alloys

In this research, the mass stopping powers, projected range, effective atomic numbers, effective electron density, radiation yield and stopping time of light and heavy charged particles such as electron, proton and alpha in the Rene alloys which consist of Rene N4, Rene N5, Rene 41, Rene 65, Rene 80, Rene 88, Rene 95 and Rene 104 were calculated for the first time. The calculations were performed by using the programs, which are called as ESTAR, SRIM and PAGEX codes. Moreover, all the results were compared with each other, and a comprehensive and comparative study of the theoretical results were presented.

Performance study of the Multi-purpose Time Projection Chamber (MTPC) using a four-component alpha source

Performance study of the Multi-purpose Time Projection Chamber (MTPC) using a four-component alpha source

Enhancing photo and X-ray detection performance of (BDA)CsPb2Br7 perovskite single crystals by removing surface defects

Enhancing photo and X-ray detection performance of (BDA)CsPb2Br7 perovskite single crystals by removing surface defects

Study of scintillation properties and performance of CsI(Tl) detectors over time

Study of scintillation properties and performance of CsI(Tl) detectors over time

Effect of large-angle incidence on particle identification performance for light-charged ([formula omitted]) particles by pulse shape analysis with a pad-type nTD silicon detector

Effect of large-angle incidence on particle identification performance for light-charged ([formula omitted]) particles by pulse shape analysis with a pad-type nTD silicon detector

Comparative studies of α-decay channel from 144Nd* and 148Sm* populated via neutron induced reactions

A comparative study of α-decay channel from the composite systems 144Nd* and 148Sm* populated via n-induced reactions- n+143Nd and n+147Sm, is done at Ebeam=5.0 MeV. The study proceeds through the Dynamical Cluster-decay Model (DCM) as suggested by an experiment performed by Gledenov et al. at Peking University, China. An attempt is made to do a theoretical investigation of decay profiles of 144Nd* and 148Sm* to analyze the effect of temperature, neck-length and angular momentum state of the hot-rotating system at common beam energy. The results are exhibited in the form of variations in fragmentation structure and the barrier modification effects that are illustrated from the barrier penetration profiles. Additionally, a competing analysis of light charge particle emission is done where the cumulative contribution of α-emission towards the decay channel is depicted in contrast to the contribution from other light particles (n, 2n,3n) or light charged particles (3H) for both the decaying systems 144Nd* and 148Sm*.

Proton Energy Spectra From Deuteron Induced Reaction on Copper At 14,5 MeV Deuteron Energy

Double differential cross sections have been measured for light-charged particle production in deuteron-induced reactions on nat Cu at incident energies of 14.5 MeV. The experiment was performed at the isochronous cyclotron of the Institute of Nuclear Physics (Kazakhstan). Charged particles were detected using a set of Si and CsI detectors from 30° to 135°, by step of 15°. The integral cross-sections were determined by integrating over the angle the double differential cross-sections. Double differential and integral charged particle emission cross-sections have been calculated by the TALYS 1.9 nuclear reaction which code based on a modified version of the exciton model of the pre-equilibrium nuclear decay. Direct, compound, and pre-equilibrium reaction contributions have been determined for the emission of proton particles.

A study on light charged particle accompanied ternary fission of 253Cf

A study on light charged particle accompanied ternary fission of 253Cf

Black hole extremality in nonlinear electrodynamics: a lesson for weak gravity and Festina Lente bounds

We study black hole extremality in nonlinear electrodynamics motivated by the Weak Gravity Conjecture (WGC) and the Festina Lente (FL) bound. For illustration, we consider the Euler-Heisenberg model and the Dirac-Born-Infeld model in asymptotically flat spacetime, de Sitter spacetime, and anti-de Sitter spacetime. We find that in all cases the extremal condition enjoys a certain monotonicity expected by the WGC. This provides evidence for the conjecture beyond the leading order corrections to the Einstein-Maxwell theory. We also study how light charged particles modify the mass-charge relation of Nariai black holes in de Sitter spacetime and discuss possible implications for the FL bound. Besides, we point out an interesting similarity between our black hole analysis and gravitational positivity bounds on scattering amplitudes.

The WASA-FRS project at GSI and its perspective

A novel technique to study bound states of exotic hadrons in subatomic nuclei, such as hypernuclei and mesic nuclei, has been developed by employing the Fragment Separator FRS and the WASA central detector at GSI. Two experiments, S447 for studying light hypernuclei, especially hypertriton and a Λnn bound state, and S490 for searching for η’ mesic-nuclei, were recently performed. Data analyses are currently in progress, and light charged particles such as protons and π± are clearly observed and identified in the both experiments. For S447, light nuclear fragments that can also be residual nuclei from decays of hypernuclei of interests have been analysed by the FRS, and a momentum resolution, Δp/p, of 5×10−4 has been achieved. Further data analyses are to be completed. The WASA-FRS project will be continued and extended with the FRS at FAIR Phase 0, and upgrading of the WASA magnet and detectors is currently in progress. Furthermore, construction of a larger detector system with the Super-FRS at FAIR Phase 1 is also under consideration.

Advances in nuclear structure via charged particle reactions with AGATA

In recent decades, gamma -ray spectroscopy has undergone a major technological leap forward, namely the technique of gamma -ray tracking, and has attained a sensitivity that is two orders of magnitude larger than that provided by the former generation of Compton-shielded arrays. Indeed the gain is comparable with the achievements since the dawn of gamma -ray spectroscopy. Such sensitivity can be further heightened by coupling gamma -ray spectrometers to other detectors that record complementary reaction products such as light-charged particles for transfer reactions and scattered ions for Coulomb excitation measurements. Nucleon transfer reactions offer an excellent mean to probe the energies of shell model single-particle orbitals and to study migration in energy of these orbitals as we venture away from stability. Such measurements can also estimate the cross sections of processes relevant to stellar evolution and nucleosynthesis. The measurement of gamma rays in coincidence with particles provides also information on the decay channel for unbound systems, which constitutes a useful input for astrophysics and nuclear structure near the drip-lines. Coulomb-excitation studies make it possible to infer collective structure in nuclei and to extract deformation properties of, in particular, open-shell systems. Here, selected examples will be presented, highlighting the power of these types of experiments when gamma -ray observation is included. The development of the experimental methods is reviewed, showing the results achieved before the advent of gamma -ray tracking. Examples of more recent experiments that have successfully exploited gamma -ray tracking with AGATA are then presented as showcases for the outstanding performance of the composite detection systems. The outlook for experiments using newly developed devices such as GRIT and other detectors such as SPIDER is described.

Reaction dynamics and in-medium nucleon-nucleon cross section with C12+H1 at 95 MeV/nucleon

Reaction dynamics and effective in-medium nucleon-nucleon $(NN)$ cross section are studied, using the antisymmetrized molecular dynamics (AMD) model with one of the simplest heavy ion collisions, $^{12}\mathrm{C}+^{1}\mathrm{H}$. The roles of different stochastic processes are studied, which are installed in the original AMD. One is the diffusion process as a part of the quantum fluctuation originated from the Fermi motion during the time evolution of the wave packets in the mean field (AMD/D). The second is a coalescence treatment for light clusters with $A\ensuremath{\le}8$ (AMD/D-COALS). The third is the collision process, installed in AMD with different form of the in-medium $NN$ cross sections. These different processes are examined, using the experimental angular distributions and energy spectra of light charged particles and intermediate mass fragments. The effective in-medium $NN$ cross sections are evaluated from the simulated AMD events and compared with the experimentally extracted values. A good agreement is obtained between the AMD values from the $^{12}\mathrm{C}$ $+$ $^{1}\mathrm{H}$ reaction at 95 MeV/nucleon and the experimental results for nuclear matter.

The light charged particle detector array at the CSNS Back-n white neutron source

The Back-n white neutron source at the China Spallation Neutron Source (CSNS) provides neutrons in the continuous energy region from 0.5 eV to 200 MeV. A spectrometer named Light charged Particle Detector Array (LPDA) is designed for the study of (n, lcp) reactions at Back-n. The main detector of the LPDA spectrometer, a 16-unit ΔE-ΔE-E telescope array, is composed of two arrays of 8-unit ΔE-ΔE-E telescope. Each telescope unit consists of a Low-Pressure Multi-Wire Proportional Chamber (LPMWPC), a Si-PIN detector, and a CsI(Tl) scintillator detector. In 2021, a neutron-proton (n-p) scattering reaction cross-section measurement experiment was accomplished as the first experiment of the telescope array. Protons can be clearly identified in the ΔE-E spectrum (LPMWPC + Si-PIN) and the ΔE-E spectrum (Si-PIN + CsI(Tl)). Cross sections of the n-p scattering reaction in the neutron energy range of several MeV are extracted. The ΔE-E method also provides new measurement opportunities for many-body neutron induced light charged-particle emission reactions.

Research on the application of pulse shape discrimination method in (n, lcp) reaction cross-section measurements

Research on the application of pulse shape discrimination method in (n, lcp) reaction cross-section measurements

Determining the nuclear temperature dependence on source neutron-proton asymmetry in heavy-ion reactions at intermediate energy* *Supported by the National Natural Science Foundation of China (12275186, 11705242, 12175156, 11805138, 11905120) and the Fundamental Research Funds For the Central Universities in China (YJ201954, YJ201820)

In this article, we investigate the dependence of nuclear temperature on emitting source neutron-proton () asymmetry with light charged particles (LCPs) and intermediate mass fragments (IMFs) generated from intermediate-velocity sources in thirteen reaction systems with different asymmetries, on , and , on , , , and at 40 MeV/nucleon. The apparent temperature values of LCPs and IMFs from different systems are deduced from the measured yields using two helium-related and eight carbon-related double isotope ratio thermometers, respectively. Then, the sequential decay effect on the experimental apparent temperature deduction with the double isotope ratio thermometers is quantitatively corrected explicitly with the aid of the quantum statistical model. The present treatment is an improvement compared to our previous studies in which an indirect method was adopted to qualitatively consider the sequential decay effect. A negligible asymmetry dependence of the real temperature after the correction is quantitatively addressed in heavy-ion reactions at the present intermediate energy, where a change of 0.1 units in source asymmetry corresponds to an absolute change in temperature of an order of 0.03 to 0.29 MeV on average for LCPs and IMFs. This conclusion is in close agreement with that inferred qualitatively via the indirect method in our previous studies.

Apparent temperatures of neutron-poor and neutron-rich compound nuclei

The possibility of the dependence of the nuclear caloric curve on neutron excess sets a limit on the accuracy of our knowledge of the nuclear equation of state, and thus impacts predictive capabilities of nuclear reaction and nuclear astrophysics models. To date, theoretical models have not reached consensus on the magnitude or sign on the asymmetry dependence. To provide constraints, we have measured evaporated particles and heavy residues for complete and incomplete fusion-evaporation reactions in inverse kinematics. The temperatures extracted from the observed light charged particles tend to favor higher temperatures for the neutron-rich fused systems, though they are near the limits of the systematic uncertainty. The present measurement may be used as an upper limit to constrain the asymmetry dependence of the nuclear caloric curve.

Detector development at the Back-n white neutron source

PurposeBack-n is a white neutron beamline at China spallation neutron source, which was established in the year of 2018. It is a powerful facility for nuclear data measurement, neutron detector calibration, and radiation effect research.MethodA series of detectors were built for different experiments, including beam monitoring, beam profile measurement, neutron induced secondaries (fission fragments, light charged particles and gamma) cross section measurement, and neutron resonance radiography, etc. A common digitization electronics and a cluster-based DAQ were developed for these detector systems. Most detectors have been employed at Back-n and serviced for experiments from the beginning of the beamline running.Results and conclusionAs an overview of detectors of Back-n, the details of the detector design and the experiment performing are described in this paper. Some developing systems, e.g., MTPC and B-MCP, are also included.