Subjects: Physics >> Nuclear Physics submitted time 2024-05-10
Abstract： [Background]: The China Spallation Neutron Source (CSNS) provides a white neutron beam with an energy range from 0.5 eV to 300 MeV and a total beam intensity of up to 107n/s/cm2, serving as an excellent experimental platform for the measurement of neutron capture reaction cross sections. During normal operation, the CSNS generates two proton bunches separated by 410 ns, consecutively striking the target, resulting in a mixed neutron beam composed of two bunches with a 410 ns interval. To avoid interference between the effects of the two bunches and maintain the energy precision of neutron capture cross sections, experimental data need to be analyzed and reconstructed to restore the effects of individual bunches. [Purpose]: The existing parsing method can yield very refined unfolding results, but it is relatively complex and has a certain usage threshold. Therefore, a more convenient data processing method needs to be found. [Methods]: This work utilized mathematical operations to analyze and reconstruct the data, with 410 ns as the unit time, and processed the data with a channel width of 4100 ns. Additionally, a comparison was made of the impacts of this method and existing methods on the accuracy of neutron incident energy. [Results]: This work proposes a simplified data processing method that achieves the same energy resolution as existing methods in the low-to-medium energy range, providing a new data processing approach for similar experimental work. [Conclusions]: The simplified data processing method presented in this study effectively addresses the issue of excessive computational costs in analyzing low to medium energy neutron data from the CSNS. It offers a practical solution for experimental work requiring accurate analysis of neutron capture reactions in this energy range.
Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-04-26
Abstract： [Background]: The High Energy Cosmic Radiation Detection Facility (HERD) is a flagship scientific instrument planned to be deployed on the Chinese Space Station, aiming to indirectly detect dark matter, accurately measure cosmic ray compositions, and conduct surveys of high-energy gamma-ray emissions. Among them, the silicon charge detector is one of the key components of HERD, used to measure the charges of cosmic rays ranging from hydrogen to nickel.[Purpose]: To validate and analyze the charge measurement capability of silicon charge detectors, a ground test system was designed for a prototype silicon charge detector beamline.[Methods]: The ground test system utilizes Xilinx's ZYNQ UltraScale+ MPSoC chip as the control chip, achieving functions including LVDS data reception, encoding and decoding, RS-422 control, and gigabit Ethernet data reception and storage. [Results]: The silicon charge detector beamline prototype participated in heavy ion beam experiments at the European Nuclear Research Center, with the ground test system collecting 100G of experimental data during the beamline experiments. [Conclusions]: The Ground Test system demonstrated good stability and reliability during the beam experiment, providing important technical support and data foundation for subsequent experiments of the HERD project's silicon charge detector.
submitted time 2024-04-24
Abstract： [Background] The RF linac dedicated to boron neutron capture therapy clinic facility(BNCT02) in our institute is mainly composed of an ion source, a low energy beam transmission line, a radio frequency quadrupole accelerator and three high energy beam transmission lines. [Purpose] This study aims to ensure the safe operation of the BNCT02 accelerator. [Methods] A machine protection system (MPS) was designed based on Yokogawa PLC and Experimental Physics and Industrial Control System (EPICS) software toolkit. In order to improve reliability and safety, the system adopts a redundant design, consisting of two completely independent subsystems with consistent main input and output signals. [Results & Conclusions] The test results show that the response time of the BNCT02 accelerator MPS is less than 1.6ms, and it has the characteristics of high stability and reliability, which meets the operational requirements of the BNCT02 accelerator.
Subjects: Physics >> Nuclear Physics submitted time 2024-02-21
Abstract： Gaseous X-ray polarimetry refers to a class of detectors used for measuring the polarization of soft X-rays.
The systematic effects of such detectors introduce residual modulation, leading to systematic biases in the
polarization detection results of the source. This paper discusses the systematic effects and their calibration and
correction using the Gas Microchannel Plate–Pixel Detector(GMPD) prototype for Polar2/Low Energy X-ray
Polarization Detector(LPD). Additionally, we proposes an algorithm that combines parameterization with Monte
Carlo simulation and Bayesian iteration to eliminate residual modulation. The residual modulation after data
correction at different energy points has been reduced to below 1%, and a good linear relationship is observed
between the polarization degree and modulation degree. The improvement in modulation degree after correction
ranges from 2% to 15%, and the results exceed those of IXPE above 5 keV.
Peer Review Status:
Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2024-01-18
Abstract： In this paper, we present a pedagogical description of the single particle dynamics for the circular accelerator. The beam dynamics of circular accelerator can be classified into the transverse motion and the longitudinal motion. The materials of this paper come from the practice of the circular accelerator's theory and design. We try to combine the physical problem and the mathematical method effectively and wholly. On the one hand, The requirement from the physical problem accelerate the developement of mathematics; On the other hand, more advanced the mathematical method, more easy the physical problem. One of the advantages is that we illustrate the beam dynamics of circular accelerator by Hamitonian Mechanics.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2023-12-24
HE Ziyang
WU Xiaoguang
JIANG Wei
LI Congbo
ZHOU Zhenxiang
SUN Qi
GUO Mingwei
WU Hongyi
LI Zhihuan
FAN Ruirui
TANG Jingyu
LI Tianxiao
HU Shouyang
ZHI Yu
SONG Jinxing
LI Peiyu
LUAN Guangyuan
ZHANG Qiwei
WANG Zhaohui
CHEN Xiongjun
Abstract： Isomer with long lifetime and high excitation energy has great significant in the fields of national strategic security and energy storage. Mastering the method of inducing isomer to decay is the key technology. However, this technology has got into trouble in recent years. For mastering the method of inducing isomer to decay, it is beneficial to start the research on the formation, excitation and de-excitation mechanism of isomer from the view of atomic nucleus structure. In terms of experimental technology, we use the white light neutron beams to bombard Hf target. We established a triple coincidence measurement system, whcih consisted of GTAF-II and HPGE, combined with white light neutron time of flight. Through the analysis of experimental data, we found the sign of the $^{178}$Hf isomeric state exciting to the transition level and releasing rapidly.
Subjects: Nuclear Science and Technology >> Particle Accelerator submitted time 2023-12-14
Abstract： The space charge effect is the core problem of high intensity proton accelerator, especially at injection and initial acceleration stages. Using the phase space painting with optimized process, will effectively eliminate the influence of space charge effect on injection and acceleration efficiency, and emittance increase. Transverse phase space painting methods can be divided into correlated painting and anti-correlated painting. In this paper, firstly, the transverse phase space paintings for the high intensity proton synchrotron are discussed in detail, including different painting methods and different implementation methods. Secondly, based on the injection system of the China Spallation Neutron Source, the beam injection process and anti-correlated painting design scheme are studied in detail. The reasons for the reduction of the actual vertical painting range and the influence of edge focusing effects of the bump magnets on the painting and beam dynamics are deeply explored. In addition, the method to perform the correlated painting based on the mechanical structure of the anti-correlated painting scheme and its key role in realizing the CSNS design goal are briefly introduced. Finally, according to the requirement of switching between different painting methods online in future accelerators, a new injection scheme that can realize correlated and anti-correlated painting simultaneously has been proposed. The new painting injection scheme has been demonstrated, simulated and optimized in detail.
Subjects: Nuclear Science and Technology >> Particle Accelerator submitted time 2023-11-07
Abstract： EPICS, a software tool extensively used in large-scale scientific experiments such as particle accelerators. Depending on the scale of the facility, the number of EPICS PV can range from tens of thousands to millions. The ability to swiftly retrieve information related to EPICS PV can notably enhance the operational efficiency and maintenance of particle accelerators. To address this requirement, we designed and developed the EPICS PV information platform. This platform provides a unified user interface that supports the querying of PV lists, real-time statuses, historical data, put logs, IOC statuses, and IOC network information. It integrates these data points to offer a comprehensive view. The user interface of the platform leverages Web technology, with the server-side developed in the Node.js environment. This is complemented by software modules from the EPICS community. In addition, programs for network information collection and other cyclical executions are developed using the Python language. At present, the EPICS PV information platform has been successfully implemented in the CSNS accelerator, where it has significantly contributed to its effective operation and maintenance.
Subjects: Physics >> Nuclear Physics submitted time 2023-10-07
Abstract： From Lienard-Wiechert potential, the near field acceleration and the far field acceleration are defined. The general acceleration law is demonstrated in combination with the Maxwell equations. The acceleration methods can be configured from the general acceleration law. The near field acceleration cab be seen as the radio frequency linear accelerator approximately. The are many kinds of the slow wave acceleration structures in the near field acceleration, the slow wave acceleration structures can be classfied into two kinds of
structure: the travelling wave acceleration structure and the standing wave acceleration structure. The RF cavity is the simplest acceleration structure, and its model is the pillbox oscillation cavity. While the slow wave acceleration structure can be equivalent to the coupling RF cavities. The fundamental characteristics of the slow wave acceleration structure can be gotten from the analytical solution and the numerical solution of the electromagnetic field in the cavity. We give the general dispersion relation for the the travelling wave acceleration structure and the standing wave acceleration structure. We pay more attention to the linear accelerator, as the acceleration of the charged particle is
finished in the acceleration structure, while the magnet just store the charged particle. Therefore, we discuss the motion of the charged particle in the linear accelerator, the motion of the charged particle is defined into the longitudinal motion and the transverse motion. We simplfy the longitudinal motion and the transverse motion into two dimensions standard maps for the nonlinear kinetics. As for the far field acceleration, there are mainly the inverse free electron laser acceleration, the inverse Cerenkov acceleration and the cyclotron
auto-resonance acceleration et al, the far field acceleration is fit for the low energy case. Under the other charges, there exists the plasma wakefield accelerator. The plasma wakefield accelerator is the most competitive candidate for the future accelerator. The research of the plasma wakefield accelerator focuses mainly on the laser plasma accelerator, while the research of the laser plasma accelerator focuses mainly the bubble model in which the high quality mono-energy electron beam is obtained. The application of the acceleratyor lies mainly
in particle physics and nuclear physics. The development of particle physics and nuclear physics is the main driving force for the development of the accelerator research. At the same time, the accelerator is applied to the synchrotron radiation, the free electron laser, the spallation neutron source and the clean nuclear power. Therefore, there exist accelerator application in many scientific research fields.
Peer Review Status:Awaiting Review
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： The research infrastructure is the basic and strategic platform of scientific and technological innovation. In the last decade, China’s research infrastructure has achieved leapfrog development in the level of observation, manufacturing, management, data acquisition, data sharing and utilization, which supports China’s scientific and technological innovation activities at a higher level. Looking into the future, the scientific research paradigm is transforming. The network, data, and computing platform will not only support the development of major science and technology infrastructure and field stations in larger, more accurate, and more advanced approach, but also contribute to the transformation of scientific research paradigm. It will become an “accelerator” and “multiplier” for major scientific and technological breakthroughs. It is also the key support for China to become the forefront of innovative countries and to enter the world’s science and technology strength.
Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-19 Cooperative journals: 《中国科学院院刊》
Abstract： Large research facilities play important roles in the fundamental and applied scientific researches in China. In recent years, the investment has been increasing in large facilities of physics frontiers which provides essential infrastructure of physics researches. These large facilities lead to big challenges to scientific research, data analysis and management. In addition to the computer technologies to build the high performance computing platform, the strategy to use and manage the data may be more important to guarantee the large facilities have the most scientific merits. Trying to facilitate the scientific productivity, this article will discuss the strategies of data sharing, data preservation and reuse, staffing and careers based on the characteristics of data generating from different facilities.
Subjects: Physics >> Nuclear Physics submitted time 2023-01-12
Abstract：
In this paper, we discuss the developing history and the present status of Free Electron Laser. Under the one dimension approximation, the basic theory for the low gain and the high gain free electron laser are given. Further, we discuss the typical facility of the high gain free electron laser, and give the basic physical design method and the design philosophy.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2022-07-25
Abstract： The motion of charged particle can be divided by the longitudinal motion and the transverse motion. The longitudinal motion is the phase motion. Under one dimensional approximation,the longitudinal motion equations are derived, the physical mechanism for the stable phase motion and its related phase condition are given. The one standard map for the longitudinalmotion is gotten, this standard map can be used for the nonlinear dynamics study. We simulated two S-Band electron linacs to prove the basic theory of the phase motion. The simulationresult agreed the basic theory well. In the common electron linac (with DC electron gun and the bunching section), We propose to replace the high voltage DC electron gun by the
photocathode RF gun directly while preserving the bunching section still to get the high peak current short electron bunch.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2022-06-13
Abstract：
In this paper, we discuss the physical background for bunch compression, the basic principle of bunch compression, and the kinds of bunch compressing. Using the fundamental theory of beam optics, one gives the basic formula of bunch compressing, proves the high order limiting terms. We analyse and discuss the design physics for single bunch compressor and two bunch compressor design for the high brightness electron linac, and summarize some physics problems in the design of linac including beam bunch compressing. As for the beam dynamics existing in the bunch compressor, we give the kinetic equations for bunch compressing taking into account of CSR effect and microbunching instability. Finally, we discuss the error problem for bunch compressor.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2021-03-03
Abstract： "
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2018-07-10
Abstract： " In this paper, we analyze and disccuss the 100 years of history for the accelerators. From the several differential vision angles: the thought seeds, the theoretical breakthrough and preparation, technical preparation, experimental experiences and the future accelerator, we expound the 100 years of history for the accelerators systemly and completely.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2018-06-20
Abstract： " In this paper, we discuss the analytical solution of the accelerating structure electromagnetic field. We mainly discuss the field and circuit method to analyze the accelerating structure. We discuss two kinds of accelerating structures: the traveling wave accelerating structure and the standing wave accelerating structure. Some results are presented in this paper.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2018-01-01
Abstract： In this paper, we continue our work [1] which analyzes the effect of high spatial harmonics on beam dynamics in RF linac. The approximate solution of the radial motion is obtained. Further, some numerical results are present using the mapping technique.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2017-01-04
Abstract：摘要 摘要 高亮度的超短电子束团的产生是目前电子直线加速器的一个研究方向。 常规加速器与基于等离子体的加速器都能产生超短（亚皮秒）束团。本文简要描述了一台产生超短电子束团加速器装置，并进行了模拟研究。
Peer Review Status:Awaiting Review
Hits
Hits
Downloads
Comment
YES