分类: 核科学技术 >> 裂变堆工程技术 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: Neutron-TPC (nTPC) is a fast neutron spectrometer based on GEM-TPC (Gas Electron Multiplier-Time Projection Chamber) and expected to be used in nuclear physics, nuclear reactor operation monitoring, and thermo-nuclear fusion plasma diagnostics. By measuring the recoiled proton energy and slopes of the proton tracks, the incident neutron energy can be deduced. It has higher n/ separation ability and higher detection efficiency than conventional neutron spectrometers. In this paper, neutron energy resolution of nTPC is studied using the analytical method. It is found that the neutron energy resolution is determined by 1) the proton energy resolution (Ep/Ep), and 2) standard deviation of slopes of the proton tracks caused by multiple Coulomb scattering (k(scattering)) and by the track fitting accuracy (k(fit)). Suggestions are made for optimizing energy resolution of nTPC. Proper choices of the cut parameters of reconstructed proton scattering angles (cut), the number of fitting track points (N), and the working gas help to improve the neutron energy resolution.
分类: 核科学技术 >> 裂变堆工程技术 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: Radiation shielding structure for C-ADS Inject-I was designed and optimized using FLUKA code. For this equipment was planned to be established in an existing tunnel hall and installed in limited space, several shielding hot spots are re-designed and analyzed respectively as they may cause radiation dose leakage and weakening of the total shielding effect. Besides, some new shielding structures are applied in the simulation process. All designed shielding structures are discussed in this paper and the results will meet the governmental criteria for radiation protection.
分类: 物理学 >> 核物理学 提交时间: 2016-09-14
摘要: Based on the standard Gaisser's formula, a modified parametrization for the sea-level cosmic-ray muon flux is introduced. The modification is verified against experimental results. The average vertical cosmic-ray muon intensity as a function of depth of standard rock is simulated using the modified formula as input to the MUSIC code. The calculated muon intensities is consistent with the experimental measurements.
分类: 物理学 >> 核物理学 提交时间: 2016-09-14
摘要: The LHC discovery of a light Higgs particle h0 (125GeV) opens up new prospect for searching heavier Higgs boson(s) at the LHC Run-2, which will unambiguously point to new physics beyond the standard model (SM). We study the detection of a heavier neutral Higgs boson H0 via di-Higgs production channel at the LHC (14TeV), H0→h0h0→WW∗γγ. This directly probes the Hhh cubic Higgs interaction, which exists in most extensions of the SM Higgs sector. For the decay products of final states WW∗, we include both pure leptonic mode WW∗→ℓν¯ℓ¯ν and semi-leptonic mode WW∗→qq¯′ℓν. We analyze signals and backgrounds by performing fast detector simulation for the full processes pp→H→hh→WW∗γγ→ℓν¯ℓ¯νγγ and pp→H→hh→WW∗γγ→ℓνqq¯′γγ, over the mass range MH=250−600GeV. For generic two-Higgs-doublet models (2HDM), we present the discovery reach of the heavier Higgs boson at the LHC Run-2, and compare it with the current Higgs global fit of the 2HDM parameter space.
分类: 物理学 >> 核物理学 提交时间: 2016-09-13
摘要: Nuclear reactors are one of the most intense, pure, controllable, cost-effective, and well-understood sources of neutrinos. Reactors have played a major role in the study of neutrino oscillations, a phenomenon that indicates that neutrinos have mass and that neutrino flavors are quantum mechanical mixtures. Over the past several decades reactors were used in the discovery of neutrinos, were crucial in solving the solar neutrino puzzle, and allowed the determination of the smallest mixing angle θ13. In the near future, reactors will help to determine the neutrino mass hierarchy and to solve the puzzling issue of sterile neutrinos.
分类: 物理学 >> 核物理学 提交时间: 2016-09-02
摘要: A careful study on the nature of the Z_c(3900) resonant structure is carried out in this work. By constructing the pertinent effective Lagrangians and considering the important final-state-interaction effects, we first give a unified description to all the relevant experimental data available, including the J/\psi\pi and \pi\pi invariant mass distributions from the e^+e^-\to J/\psi\pi\pi process, the h_c\pi distribution from e^+e^-\to h_c\pi\pi and also the D\bar{D}^{*} spectrum in the e^+e^-\to D\bar{D}^{*}\pi process. After fitting the unknown parameters to the previous data, we search the pole in the complex energy plane and only find one pole in the nearby energy region in different Riemann sheets. Therefore we conclude that Z_c(3900) is of D\bar{D}^* molecular nature, according to the pole counting rule method. We emphasize that the conclusion based upon pole counting method is not trivial, since both the D\bar{D}^{*} contact interactions and the explicit Z_c exchanges are introduced in our analyses and they lead to the same conclusion.