Subjects: Physics >> Nuclear Physics Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-02-27
Abstract: The high-intensity heavy-ion accelerator facility (HIAF) under construction is equipped with an advanced radioactive beam line HFRS, which will provide a new opportunity for the research of high-energy radionuclide beam physics in China.The characteristic of HFRS is high intensity, This puts forward very strict requirements for particle recognition energy loss detector.The traditional energy loss detector generally adopts the analog plug-in technology route of preamplifier, main amplifier and ADC for signal processing.This scheme has some problems, such as slow electronic response, poor flexibility and difficulty in dealing with serious pulse pile-up at high count rate. We propose a new applicable to high count rate energy loss detector scheme.The signal of the energy loss detector is initially amplified by the fast charge sensitive preamplifier, and Then the waveform is directly collected by waveform digitizer and then processed by digital algorithm.And use the Multiple Sampling Ionization Chamber (MUSIC) of secondary beam line of lanzhou RIBLL2 for the radioactive source and beam test.Using the 3 components 𝛼 source test, using digital shaping algorithm processing for acquisition of waveform, energy resolution (FWHM) of up to 1.31%.In RIBLL2 provide 300 MeV/u of 56Fe beam test, uses the time constant of 𝜏f = 2 𝜇𝑠 of fast charge sensitive preamplifier on the count rate is close to 1 MHz is still not occurred pulse pile-up obviously.
Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics Subjects: Physics >> Nuclear Physics submitted time 2024-02-26
Abstract: Cosmic rays are used for the calibration of the Veto detector at ETF in HIRFL-CSR of the Cooling Storage
Ring of Heavy Ion Research Facility in Lanzhou(HIRFL-CSR). The work is divided into two parts: position calibration
and time calibration. The hit positions of particles are obtained by position calibration and an uniform standard of the
measurement of particle hit time in the Veto detector is built through time calibration. The information of position and
time of particles serves as important criteria for eliminating changed particle events that hit the neutron wall detector,
providing support for the realization of the physical objectives of the neutron wall detector. A 2.53 cm position resolution
and a 1.09 ns time resolution have been achieved in this paper.
Subjects: Physics >> Nuclear Physics submitted time 2023-11-08
Abstract: From the empirical phenomena of fragment distributions in nuclear spallation reactions, semiempirical formulas named SPAGINS were constructed to predict fragment crosssections in high-energy γ-induced nuclear spallation reactions (PNSR). In constructing the SPAGINS formulas, theoretical models, including the TALYS toolkit, SPACS, and Rudstam formulas, were employed to study the general phenomenon of fragment distributions in PNSR with incident energies ranging from 100 to 1000 MeV. Considering the primary characteristics of PNSR, the SPAGINS formulas modify the EPAX and SPACS formulas and efficiently reproduce the measured data. The SPAGINS formulas provide a new and effective tool for predicting fragment production in PNSR.
Subjects: Management Science >> Science ology and Management Subjects: Library Science,Information Science >> Information Science submitted time 2022-07-10
Abstract: In order to deeply explore the value system levels and technical approaches related to the external norms of scientific research integrity, based on a multidisciplinary theoretical perspective, the difficulties and irrational risks of the institutionalized practice of the measurement and evaluation of scientific research integrity have been specifically investigated and theoretically reflected, and it is clear that: ① Scientific research The ethical nature of honesty and the social relational practical characteristics of its evaluation; ② the standard value scale of scientific research fields and the original functional attributes of scientific research writings; ③ the institutionalized logic and institutional locking risk of evaluating scientific research integrity by relying on public authority metrics; ④ Optimize the future direction of technological approach and institutional supply. The research conclusions have fundamental theoretical support significance for avoiding blind institutional migration and technical reference, building institutional advantages that are conducive to the self-reliance and self-improvement of the national science and technology system, and promoting the transformation of scientific research integrity from crisis response to long-term governance.
Peer Review Status:Awaiting Review
Subjects: Management Science >> Science ology and Management Subjects: Library Science,Information Science >> Information Science submitted time 2022-03-22
Abstract:为探寻科研诚信建设制度供给的理论进路、理性定义政府在科研建制和科学规范中的未来角色,本研究明确了科研诚信内部规范和科研诚信外部规范的制度范式区分,并基于经济学、法学、社会学、管理学等基本规律从学理层面和科学制度化视角反思了科研诚信内部规范的合理性及其失灵原因,指明了政府在科研诚信建设及科研体制改革中的放、管、服内容与边界。研究对于完善科学政策学理论体系,促进思想界、学术界参与科研诚信外部规范相关理论和技术的批判完善与前瞻性建构具有基础性意义。
Peer Review Status:Awaiting Review
Subjects: Mathematics >> Mathematical Physics submitted time 2021-06-16
Abstract: In this paper, we mainly discuss the copositivity of 4th order symmetric tensor defined by scalar dark matter stable under a $\mathbb{Z}_{3}$ discrete group, and obtain an analytically necessary and sufficient condition of the copositivity of such a class of tensors. Furthermore, this analytic expression may be used to verify the vacuum stability for $\mathbb{Z}_{3}$ scalar dark matter. "
Peer Review Status:Awaiting Review
Subjects: Mathematics >> Mathematical Physics submitted time 2019-11-23
Abstract: " The strict opositivity of 4th order symmetric tensor may apply to detect vacuum stability of general scalar potential. For finding analytical expressions of (strict) opositivity of 4th order symmetric tensor, we may reduce its order to 3rd order to better deal with it. So, it is provided that several analytically sufficient conditions for the copositivity of 3th order 2 dimensional (3 dimensional) symmetric tensors. Subsequently, applying these conclusions to 4th order tensors, the analytically sufficient conditions of copositivity are proved for 4th order 2 dimensional and 3 dimensional symmetric tensors. Finally, we apply these results to present analytical vacuum stability conditions for vacuum stability for $\mathbb{Z}_3$ scalar dark matter. "
Peer Review Status:Awaiting Review
Subjects: Mathematics >> Control and Optimization. submitted time 2019-08-30
Abstract: " In particle physics, scalar potentials have to be bounded from below in order for the physics to make sense. The precise expressions of checking lower bound of scalar potentials are essential, which is an analytical expression of checking copositivity and positive definiteness of tensors given by such scalar potentials. Because the tensors given by general scalar potential are 4th order and symmetric, our work mainly focuses on finding precise expressions to test copositivity and positive definiteness of 4th order tensors in this paper. First of all, an analytically sufficient and necessary condition of positive definiteness is provided for 4th order 2 dimensional symmetric tensors. For 4th order 3 dimensional symmetric tensors, we give two analytically sufficient conditions of (strictly) cpositivity by using proof technique of reducing orders or dimensions of such a tensor. Furthermore, an analytically sufficient and necessary condition of copositivity is showed for 4th order 2 dimensional symmetric tensors. We also give several distinctly analytically sufficient conditions of (strict) copositivity for 4th order 2 dimensional symmetric tensors. Finally, we apply these results to check lower bound of scalar potentials, and to present analytical vacuum stability conditions for potentials of two real scalar fields and the Higgs boson. "
Peer Review Status:Awaiting Review
Subjects: Mathematics >> Mathematics (General) submitted time 2017-12-12
Abstract: In this paper, we introduce the concept of Z$_1$-eigenvalue to infinite dimensional generalized Hilbert tensors (hypermatrix) $\mathcal{H}_\lambda^{\infty}=(\mathcal{H}_{i_{1}i_{2}\cdots i_{m}})$, $$ \mathcal{H}_{i_{1}i_{2}\cdots i_{m}}=\frac{1}{i_{1}+i_{2}+\cdots i_{m}+\lambda}, \lambda\in \mathbb{R}\setminus\mathbb{Z}^-;\ i_{1},i_{2},\cdots,i_{m}=0,1,2,\cdots,n,\cdots, $$ and proved that its $Z_1$-spectral radius is not larger than $\pi$ for $\lambda>\frac{1}{2}$, and is at most $\frac{\pi}{\sin{\lambda\pi}}$ for $\frac{1}{2}\geq \lambda>0$. Besides, the upper bound of $Z_1$-spectral radius of an $m$th-order $n$-dimensional generalized Hilbert tensor $\mathcal{H}_\lambda^n$ is obtained also, and such a bound only depends on $n$ and $\lambda$.
Peer Review Status:Awaiting Review