Nuclear Science and Techniques最新文献

DD4hep serves as a generic detector description toolkit recommended for offline software development in next-generation high-energy physics (HEP) experiments. Conversely, Filmbox (FBX) stands out as a widely used 3D modeling file format within the 3D software industry. In this paper, we introduce a novel method that can automatically convert complex HEP detector geometries from DD4hep description into 3D models in the FBX format. The feasibility of this method was demonstrated by its application to the DD4hep description of the Compact Linear Collider detector and several sub-detectors of the super Tau-Charm facility and circular electron-positron collider experiments. The automatic DD4hep–FBX detector conversion interface provides convenience for further development of applications, such as detector design, simulation, visualization, data monitoring, and outreach, in HEP experiments.

The sPHENIX experiment is a new generation of large acceptance detectors at the relativistic heavy ion collider at Brookhaven National Laboratory, with scientific goals focusing on probing the strongly interacting Quark–Gluon plasma with hard probes of jets, open heavy flavor particles, and (Upsilon) production. The EMCal detector, which covers the pseudo-rapidity region of (|eta | le 1.1), is an essential subsystem of sPHENIX. In this study, we focused on producing and testing EMCal blocks covering a pseudo-rapidity of (|eta | in [0.8, 1.1]). These, in conjunction with the central pseudo-rapidity EMCal blocks, significantly enhance the sPHENIX physics capability of the jet and (Upsilon) particle measurements. In this paper, the detector module production and testing of sPHENIX W-powder/scintillating fiber (W/ScFi) electromagnetic calorimeter blocks are presented. The selection of the tungsten powder, mold fabrication, QA procedures, and cosmic ray test results are discussed.

This study proposes a novel particle encoding mechanism that seamlessly incorporates the quantum properties of particles, with a specific emphasis on constituent quarks. The primary objective of this mechanism is to facilitate the digital registration and identification of a wide range of particle information. Its design ensures easy integration with different event generators and digital simulations commonly used in high-energy experiments. Moreover, this innovative framework can be easily expanded to encode complex multi-quark states comprising up to nine valence quarks and accommodating an angular momentum of up to 99/2. This versatility and scalability make it a valuable tool.

Calcium production and the stellar evolution of first-generation stars remain fascinating mysteries in astrophysics. As one possible nucleosynthesis scenario, break-out from the hot carbon–nitrogen–oxygen (HCNO) cycle was thought to be the source of the calcium observed in these oldest stars. However, according to the stellar modeling, a nearly tenfold increase in the thermonuclear rate ratio of the break-out (^{19})F(p, (gamma))(^{20})Ne reaction with respect to the competing (^{19})F(p,(alpha))(^{16})O back-processing reaction is required to reproduce the observed calcium abundance. We performed a direct measurement of this break-out reaction at the China Jinping underground laboratory. The measurement was performed down to the low-energy limit of (E_mathrm {c.m.}) = 186 keV in the center-of-mass frame. The key resonance was observed at 225.2 keV for the first time. At a temperature of approximately 0.1 GK, this new resonance enhanced the thermonuclear (^{19})F(p, (gamma))(^{20})Ne rate by up to a factor of (approx) 7.4, compared with the previously recommended NACRE rate. This is of particular interest to the study of the evolution of the first stars and implies a stronger breakdown in their “warm” CNO cycle through the (^{19})F(p, (gamma))(^{20})Ne reaction than previously envisioned. This break-out resulted in the production of the calcium observed in the oldest stars, enhancing our understanding of the evolution of the first stars.

Neutron resonance imaging (NRI) has recently emerged as an appealing technique for neutron radiography. Its complexity surpasses that of conventional transmission imaging, as it requires a high demand for both a neutron source and detector. Consequently, the progression of NRI technology has been sluggish since its inception in the 1980s, particularly considering the limited studies analyzing the neutron energy range above keV. The white neutron source (Back-n) at the China Spallation Neutron Source (CSNS) provides favorable beam conditions for the development of the NRI technique over a wide neutron energy range from eV to MeV. Neutron-sensitive microchannel plates (MCP) have emerged as a cutting-edge tool in the field of neutron detection owing to their high temporal and spatial resolutions, high detection efficiency, and low noise. In this study, we report the development of a (^{10})B-doped MCP detector, along with its associated electronics, data processing system, and NRI experiments at the Back-n. Individual heavy elements such as gold, silver, tungsten, and indium can be easily identified in the transmission images by their characteristic resonance peaks in the 1–100 eV energy range; the more difficult medium-weight elements such as iron, copper, and aluminum with resonance peaks in the 1–100 keV energy range can also be identified. In particular, results in the neutron energy range of dozens of keV (Aluminum) are reported here for the first time.

Experimental scratch tests and first-principles calculations were used to investigate the adhesion property of AlCrNbSiTi high-entropy alloy (HEA) coatings on zirconium substrates. AlCrNbSiTi HEA and Cr coatings were deposited on Zr alloy substrates using multi-arc ion plating technology, and scratch tests were subsequently conducted to estimate the adhesion property of the coatings. The results indicated that Cr coatings had better adhesion strength than HEA coatings, and the HEA coatings showed brittleness. The special quasi-random structure approach was used to build HEA models, and Cr/Zr and HEA/Zr interface models were employed to investigate the cohesion between the coatings and Zr substrate using first-principles calculations. The calculated interface energies showed that the cohesion between the Cr coating and the Zr substrate was stronger than that of the HEA coating with Zr. In contrary to Al or Si in the HEA coating, Cr, Nb, and Ti atoms binded strongly with Zr substrate. Based on the calculated elastic constants, it was found that low Cr and high Al content decreased the mechanical performances of HEA coatings. Finally, this study demonstrated the utilization of a combined approach involving first-principles calculations and experimental studies for future HEA coating development.

The octupole deformation and collectivity in octupole double-magic nucleus ({^{144}textrm{Ba}}) are investigated using the Cranking covariant density functional theory in a three-dimensional lattice space. The reduced B(E3) transition probability is implemented for the first time in semiclassical approximation based on the microscopically calculated electric octupole moments. The available data, including the I-(omega) relation and electric transitional probabilities B(E2) and B(E3) are well reproduced. Furthermore, it is shown that the ground state of ({^{144}textrm{Ba}}) exhibits axial octupole and quadrupole deformations that persist up to high spins ((Iapprox 24hbar)).

Neutron-sensitive microchannel plates (nMCPs) have applications in neutron detection, including energy spectrum measurements, neutron-induced cross sections, and neutron imaging. ({}^{10})B-doped MCPs (B-MCPs) have attracted significant attention owing to their potential for exhibiting a high neutron detection efficiency over a large neutron energy range. Good spatial and temporal resolutions are useful for neutron energy-resolved imaging. However, their practical applications still face many technical challenges. In this study, a B-MCP with 10 mol% ({}^{10})B was tested for its response to wide-energy neutrons from eV to MeV at the Back-n white neutron source at the China Spallation Neutron Source. The neutron detection efficiency was calibrated at 1 eV, which is approximately 300 times that of an ordinary MCP and indicates the success of ({}^{10})B doping. The factors that caused the reduction in the detection efficiency were simulated and discussed. The neutron energy spectrum obtained using B-MCP was compared with that obtained by other measurement methods, and showed very good consistency for neutron energies below tens of keV. The response is more complicated at higher neutron energy, at which point the elastic and nonelastic reactions of all nuclides of B-MCP gradually become dominant. This is beneficial for the detection of neutrons, as it compensates for the detection efficiency of B-MCP for high-energy neutrons.

The SSRF phase-II beamline project was launched in 2016. Its major goal was to establish a systematic state-of-the-art experimental facility for third-generation synchrotron radiation to solve problems in cutting-edge science and technology. Currently, the construction is fully completed. All 16 newly built beamlines with nearly 60 experimental methods passed acceptance testing by the Chinese Academy of Sciences and are in operation.