轻子散射实验是探索核子与原子核结构的理想工具。中国电子离子对撞机(Electron Ion Collider in China,EicC)建议书设想在已开建的强流重离子加速器装置(High Intensity heavy ion Accelerator Facility,HIAF)的基础上,升级质子束流为2...轻子散射实验是探索核子与原子核结构的理想工具。中国电子离子对撞机(Electron Ion Collider in China,EicC)建议书设想在已开建的强流重离子加速器装置(High Intensity heavy ion Accelerator Facility,HIAF)的基础上,升级质子束流为20 GeV的极化束流,并建造2.8~5 GeV极化电子束流,从而实现质心系能量为15~20 GeV的双极化电子-离子对撞。EicC设计的亮度为(2~4)×10^33cm^-2·s^-1,质子束流极化率达到70%,电子束流极化率达到80%。该装置除了能提供极化轻离子束流(例如:氦-3)外,也可产生非极化重离子束流(碳-12~铀-238)。EicC将聚焦核子海夸克部分子结构、原子核物质结构与性质、奇特强子态三个方面的物理研究。高亮度、高精度的对撞机有助于精确地测量核子结构函数并对核子进行三维成像,揭示强相互作用的动力学规律;原子核部分子分布包括核子短程关联以及原子核介质效应同样是该提案的重要科学目标;EicC能区接近重味夸克产生阈值,在研究重味强子谱方面拥有低背景的独特优势,有助于发现研究新的奇特强子态。质子质量起源问题也可以通过重味矢量介子的产生来研究。为了完成上述物理目标,我们将利用最先进的探测器技术建造接近全立体角覆盖的EicC对撞机谱仪。在准备EicC白皮书的过程中,我们得到世界各国专家的支持。EicC的物理与已有的实验和美国即将建设的EIC中的物理项目相互补充。EicC的建成及运行有望引领前沿的中高能核物理研究,使我国在加速器和探测器先进技术等领域实现跨越式发展,为我国核物理与强子物理以及相关科学领域提供大型综合实验平台与人才培养基地。展开更多
Excitation functions have been measured for the dissipative products of 4≤Z≤12 in ^(19)F+^(45)Sc reaction from 102 to ^(108)MeV by a step of 300keV at θl=42°.The energy coherence widths have been extracted and...Excitation functions have been measured for the dissipative products of 4≤Z≤12 in ^(19)F+^(45)Sc reaction from 102 to ^(108)MeV by a step of 300keV at θl=42°.The energy coherence widths have been extracted and the dinuclear system lifetimes of the order of 10^(-21 ) s have been deduced by analysing the cross section Auctuations.展开更多
The clinical trials of tumor therapy using heavy ions beam 12C are now in progress at Institute of Modern Physics in Lanzhou. In order to achieve the precise radiotherapy with the high energy 12C beam in active pencil...The clinical trials of tumor therapy using heavy ions beam 12C are now in progress at Institute of Modern Physics in Lanzhou. In order to achieve the precise radiotherapy with the high energy 12C beam in active pencil beam scanning mode, we have developed an ionization chamber(IC) as an online monitor for beam intensity and also a dosimeter after calibration. Through the choosing of working gas and voltage, optimizing of the electrics and the read-out system, calibrating the linearity, the detector system provide us one of the simple and highly reliable way to monitoring the beam during the active pencil beam scanning treatments. The measurement results of this detector system show that it could work well under the condition of high energy 12C beam in active pencil beam scanning mode.展开更多
In this paper we present a timing detector which has low detection threshold and is radiation-resistant.The photons induced by radioactive beam ions passing through a thin plastic-scintillator foil BC422,emit from the...In this paper we present a timing detector which has low detection threshold and is radiation-resistant.The photons induced by radioactive beam ions passing through a thin plastic-scintillator foil BC422,emit from the foil center corresponding to one focal point of an aluminum ellipsoidal mirror and are reflected to another focus point at which the cathode of a photomultiplier tube locates.A time resolution of about 115 ps can be achieved for1 2N of 58.5 MeV/u and 130 ps for1 7B of 43.7 MeV/u.The counting rate up to 10 8packets per second(pps) is allowed.展开更多
Excitation functions for projectile-like fragments from ^(19)F+^(51)V reaction have been measured at 102.25 to 109.50MeV in 250keV steps.A TOF+(ΔE-E)telescope atθ_(L)=21.7°is used to identify atomic number Z an...Excitation functions for projectile-like fragments from ^(19)F+^(51)V reaction have been measured at 102.25 to 109.50MeV in 250keV steps.A TOF+(ΔE-E)telescope atθ_(L)=21.7°is used to identify atomic number Z and mass number A of ejectiles simultaneously.Fluctuations of the dissipative cross section for a series of isotopes are observed.Their coherence energy widths are extracted by generalized statistical fluctuation analysis and the dependence on mass number and on N/Z values are observed for the first time.展开更多
Isotope 223U synthesized and identified[1;2].αenergy of 8 780(40)keV and a half-life of 55(10)μs.Theαenergy was calculated by subtracting knownαenergy of 219Th from measured decay sum energy of 223U and its daught...Isotope 223U synthesized and identified[1;2].αenergy of 8 780(40)keV and a half-life of 55(10)μs.Theαenergy was calculated by subtracting knownαenergy of 219Th from measured decay sum energy of 223U and its daughter 219Th.Based on the advanced digital pulse processing technique,a new measurement forα-particle energy and half-life of 223U was performed at the gas-filled recoil separator,Spectrometer for Heavy Atoms and Nuclear Structure(SHANS).The isotope 223U was produced in the fusion-evaporation reaction 187Re(40Ar,p3n)223U.展开更多
Nuclear mass measurements provide valuable information on the nuclear binding energy which reflects the summed result of all interactions among its constituent protons and neutrons. The systematic and accurate knowled...Nuclear mass measurements provide valuable information on the nuclear binding energy which reflects the summed result of all interactions among its constituent protons and neutrons. The systematic and accurate knowledge of nuclear masses have wide application in many areas of subatomic physics ranging from nuclear structure and astrophysics to the fundamental interactions and symmetries depending on the achieved mass precision[1].展开更多
文摘轻子散射实验是探索核子与原子核结构的理想工具。中国电子离子对撞机(Electron Ion Collider in China,EicC)建议书设想在已开建的强流重离子加速器装置(High Intensity heavy ion Accelerator Facility,HIAF)的基础上,升级质子束流为20 GeV的极化束流,并建造2.8~5 GeV极化电子束流,从而实现质心系能量为15~20 GeV的双极化电子-离子对撞。EicC设计的亮度为(2~4)×10^33cm^-2·s^-1,质子束流极化率达到70%,电子束流极化率达到80%。该装置除了能提供极化轻离子束流(例如:氦-3)外,也可产生非极化重离子束流(碳-12~铀-238)。EicC将聚焦核子海夸克部分子结构、原子核物质结构与性质、奇特强子态三个方面的物理研究。高亮度、高精度的对撞机有助于精确地测量核子结构函数并对核子进行三维成像,揭示强相互作用的动力学规律;原子核部分子分布包括核子短程关联以及原子核介质效应同样是该提案的重要科学目标;EicC能区接近重味夸克产生阈值,在研究重味强子谱方面拥有低背景的独特优势,有助于发现研究新的奇特强子态。质子质量起源问题也可以通过重味矢量介子的产生来研究。为了完成上述物理目标,我们将利用最先进的探测器技术建造接近全立体角覆盖的EicC对撞机谱仪。在准备EicC白皮书的过程中,我们得到世界各国专家的支持。EicC的物理与已有的实验和美国即将建设的EIC中的物理项目相互补充。EicC的建成及运行有望引领前沿的中高能核物理研究,使我国在加速器和探测器先进技术等领域实现跨越式发展,为我国核物理与强子物理以及相关科学领域提供大型综合实验平台与人才培养基地。
基金Supported by the National Natural Science Foundation of China.
文摘Excitation functions have been measured for the dissipative products of 4≤Z≤12 in ^(19)F+^(45)Sc reaction from 102 to ^(108)MeV by a step of 300keV at θl=42°.The energy coherence widths have been extracted and the dinuclear system lifetimes of the order of 10^(-21 ) s have been deduced by analysing the cross section Auctuations.
基金Supported by the National Nature Science Foundation of China (No. 10305015, No.10475098)the Major Program of the Chinese Academy of Science (No. O701050YZD)
文摘The clinical trials of tumor therapy using heavy ions beam 12C are now in progress at Institute of Modern Physics in Lanzhou. In order to achieve the precise radiotherapy with the high energy 12C beam in active pencil beam scanning mode, we have developed an ionization chamber(IC) as an online monitor for beam intensity and also a dosimeter after calibration. Through the choosing of working gas and voltage, optimizing of the electrics and the read-out system, calibrating the linearity, the detector system provide us one of the simple and highly reliable way to monitoring the beam during the active pencil beam scanning treatments. The measurement results of this detector system show that it could work well under the condition of high energy 12C beam in active pencil beam scanning mode.
基金Supported by National Nature Science Foundation of China (No.10205019,10475098)Doctoral Foundation of Southwest University (No.SWNUB2005028)Hundred Talent Project of CAS (0501080BR0)
文摘In this paper we present a timing detector which has low detection threshold and is radiation-resistant.The photons induced by radioactive beam ions passing through a thin plastic-scintillator foil BC422,emit from the foil center corresponding to one focal point of an aluminum ellipsoidal mirror and are reflected to another focus point at which the cathode of a photomultiplier tube locates.A time resolution of about 115 ps can be achieved for1 2N of 58.5 MeV/u and 130 ps for1 7B of 43.7 MeV/u.The counting rate up to 10 8packets per second(pps) is allowed.
基金Supported by the National Natural Science Foundation of China.
文摘Excitation functions for projectile-like fragments from ^(19)F+^(51)V reaction have been measured at 102.25 to 109.50MeV in 250keV steps.A TOF+(ΔE-E)telescope atθ_(L)=21.7°is used to identify atomic number Z and mass number A of ejectiles simultaneously.Fluctuations of the dissipative cross section for a series of isotopes are observed.Their coherence energy widths are extracted by generalized statistical fluctuation analysis and the dependence on mass number and on N/Z values are observed for the first time.
文摘Isotope 223U synthesized and identified[1;2].αenergy of 8 780(40)keV and a half-life of 55(10)μs.Theαenergy was calculated by subtracting knownαenergy of 219Th from measured decay sum energy of 223U and its daughter 219Th.Based on the advanced digital pulse processing technique,a new measurement forα-particle energy and half-life of 223U was performed at the gas-filled recoil separator,Spectrometer for Heavy Atoms and Nuclear Structure(SHANS).The isotope 223U was produced in the fusion-evaporation reaction 187Re(40Ar,p3n)223U.
文摘Nuclear mass measurements provide valuable information on the nuclear binding energy which reflects the summed result of all interactions among its constituent protons and neutrons. The systematic and accurate knowledge of nuclear masses have wide application in many areas of subatomic physics ranging from nuclear structure and astrophysics to the fundamental interactions and symmetries depending on the achieved mass precision[1].
