Based on shell model of nuclei, the influence of a high magnetic field on β^＋ decay in the crusts of accreting neutron stars is analyzed. The magnetic field effect on 54 Mn is discussed. The results show that a weak...Based on shell model of nuclei, the influence of a high magnetic field on β^＋ decay in the crusts of accreting neutron stars is analyzed. The magnetic field effect on 54 Mn is discussed. The results show that a weak magnetic field makes little effect on β^＋ decay but a strong magnetic field （B 〉 10^11 G） improves β^＋ decay rates obviously. The conclusion derived will benefit to develop further research on nuclear astrophysics in the future.展开更多
A new kind of electron source, the photoemissive monoenergetic electron source has been invented for calibrating the beta--magnetic spectrometer. It produceselectrons in the form of simulating a radioactive monoenerge...A new kind of electron source, the photoemissive monoenergetic electron source has been invented for calibrating the beta--magnetic spectrometer. It produceselectrons in the form of simulating a radioactive monoenergetic electron source andcan be made in any shape and size according tO the demands of experimentS. In thispaper, the principles and basic constructions of the photoemissive monoenergeticelectron source are described, the resultS of calibrating our 2’l’x bead--magneticspectrometer with a single strip arc shaped photoemissive monoenergetic electronsource are listed, a new way for determining resolution function of experimentslsystem in the research of neutrino rest mass has been posed and one of its actualapplications is also given.展开更多
PandaX is a large liquid-xenon detector experiment usable for direct dark-matter detection and 136Xe double-beta decay search.The central vessel was designed to accommodate a staged target volume increase from initial...PandaX is a large liquid-xenon detector experiment usable for direct dark-matter detection and 136Xe double-beta decay search.The central vessel was designed to accommodate a staged target volume increase from initially 120 kg(stage I)to 0.5 t(stage II)and eventually to a multi-ton scale.The experiment is located in the Jinping Deep-Underground Laboratory in Sichuan,China.The detector operates in dual-phase mode,allowing detection of both prompt scintillation,and ionization charge through proportional scintillation.In this paper a detailed description of the stage I detector design and performance as well as results established during the commissioning phase are presented.展开更多
Experimental data ofβ--decay half-lives of nuclei with atomic number between 20 and 190 are investigated.A systematic formula has been proposed to calculateβ^--decay half-lives of neutron-rich nuclei,with a particul...Experimental data ofβ--decay half-lives of nuclei with atomic number between 20 and 190 are investigated.A systematic formula has been proposed to calculateβ^--decay half-lives of neutron-rich nuclei,with a particular consideration on shell and pair effects,the decay energy Q as well as the nucleon numbers(Z,N).Although the formula has relatively few parameters,it reproduces the experimentalβ^--decay half-lives of neutron-rich nuclei very well.The predicted half-lives for the r-process relevant nuclei obtained with the current formula serve as reliable input in the r-process model calculations.展开更多
Searching for the neutrinoless double beta decay(NLDBD)is now regarded as the topmost promising technique to explore the nature of neutrinos after the discovery of neutrino masses in oscillation experiments.Panda X-II...Searching for the neutrinoless double beta decay(NLDBD)is now regarded as the topmost promising technique to explore the nature of neutrinos after the discovery of neutrino masses in oscillation experiments.Panda X-III(particle and astrophysical xenon experiment III)will search for the NLDBD of136Xe at the China Jin Ping Underground Laboratory(CJPL).In the first phase of the experiment,a high pressure gas Time Projection Chamber(TPC)will contain 200 kg,90%136Xe enriched gas operated at10 bar.Fine pitch micro-pattern gas detector(Microbulk Micromegas)will be used at both ends of the TPC for the charge readout with a cathode in the middle.Charge signals can be used to reconstruct the electron tracks of the NLDBD events and provide good energy and spatial resolution.The detector will be immersed in a large water tank to ensure～5 m of water shielding in all directions.The second phase,a ton-scale experiment,will consist of five TPCs in the same water tank,with improved energy resolution and better control over backgrounds.展开更多
β-decay properties of N=18-22,Z=10-14 nuclei are analyzed with a new shell-model Hamiltonian using the Gogny densitydependent interaction.The Gogny force which has been widely and successfully used in mean-field theo...β-decay properties of N=18-22,Z=10-14 nuclei are analyzed with a new shell-model Hamiltonian using the Gogny densitydependent interaction.The Gogny force which has been widely and successfully used in mean-field theory can provide reasonable two-body matrix elements for cross-shell calculations.The log f t values andβ-decay level schemes are systematically studied using the D1S-Gogny interaction and compared with the SDPF-M results and experimental data.It is shown that the new Hamiltonian provides reliable results forβ-decay along with subtle level schemes for this region.Shell-model calculations with Gogny interaction can lead to a successful description of nuclei in and around the N=20 island of inversion and supplements experiment where sufficient data are not available.展开更多
In this work, the ft values of the 0+ →0+ superallowed Fermi beta decays have been investigated. In the calculations, the shell model has been modified by Pyatov's restoration method because of the isospin breaki...In this work, the ft values of the 0+ →0+ superallowed Fermi beta decays have been investigated. In the calculations, the shell model has been modified by Pyatov's restoration method because of the isospin breaking and the transition matrix elements have been found by means of the quasi-particle random phase approximation (QRPA).展开更多
基金The project supported by National Natural Science Foundation of China under Grant No. 10347008
文摘Based on shell model of nuclei, the influence of a high magnetic field on β^＋ decay in the crusts of accreting neutron stars is analyzed. The magnetic field effect on 54 Mn is discussed. The results show that a weak magnetic field makes little effect on β^＋ decay but a strong magnetic field （B 〉 10^11 G） improves β^＋ decay rates obviously. The conclusion derived will benefit to develop further research on nuclear astrophysics in the future.
文摘A new kind of electron source, the photoemissive monoenergetic electron source has been invented for calibrating the beta--magnetic spectrometer. It produceselectrons in the form of simulating a radioactive monoenergetic electron source andcan be made in any shape and size according tO the demands of experimentS. In thispaper, the principles and basic constructions of the photoemissive monoenergeticelectron source are described, the resultS of calibrating our 2’l’x bead--magneticspectrometer with a single strip arc shaped photoemissive monoenergetic electronsource are listed, a new way for determining resolution function of experimentslsystem in the research of neutrino rest mass has been posed and one of its actualapplications is also given.
基金supported by a 985 grant from Shanghai Jiao Tong Universitythe National Basic Research Program of China (Grant No. 2010CB833005)+4 种基金the National Natural Science Foundation of China (Grant No. 11055003)the Office of Science and Technology in Shanghai Municipal Government (Grant No. 11DZ2260700)sponsored by Shandong University, Peking Universitythe University of Marylandthe University of Michigan
文摘PandaX is a large liquid-xenon detector experiment usable for direct dark-matter detection and 136Xe double-beta decay search.The central vessel was designed to accommodate a staged target volume increase from initially 120 kg(stage I)to 0.5 t(stage II)and eventually to a multi-ton scale.The experiment is located in the Jinping Deep-Underground Laboratory in Sichuan,China.The detector operates in dual-phase mode,allowing detection of both prompt scintillation,and ionization charge through proportional scintillation.In this paper a detailed description of the stage I detector design and performance as well as results established during the commissioning phase are presented.
基金supported by the National Natural Science Foundation of China(Grant Nos.11490563 and 11375269)the National Basic Research Program of China(Grant No.2013CB834406)the National Key Research and Development Program of China(Grant No.2016YFA0400502)
文摘Experimental data ofβ--decay half-lives of nuclei with atomic number between 20 and 190 are investigated.A systematic formula has been proposed to calculateβ^--decay half-lives of neutron-rich nuclei,with a particular consideration on shell and pair effects,the decay energy Q as well as the nucleon numbers(Z,N).Although the formula has relatively few parameters,it reproduces the experimentalβ^--decay half-lives of neutron-rich nuclei very well.The predicted half-lives for the r-process relevant nuclei obtained with the current formula serve as reliable input in the r-process model calculations.
基金supported by the National Key Programme for Research and Development (NKPRD) (Grant No. 2016YFA0400300)Shanghai Jiao Tong University (SJTU) for their financial and technical support+1 种基金technical and administrative assistance from China Jin Ping Underground Laboratory (CJPL)the European Research Council (Grant No. ERC-2009-St G-240054)
文摘Searching for the neutrinoless double beta decay(NLDBD)is now regarded as the topmost promising technique to explore the nature of neutrinos after the discovery of neutrino masses in oscillation experiments.Panda X-III(particle and astrophysical xenon experiment III)will search for the NLDBD of136Xe at the China Jin Ping Underground Laboratory(CJPL).In the first phase of the experiment,a high pressure gas Time Projection Chamber(TPC)will contain 200 kg,90%136Xe enriched gas operated at10 bar.Fine pitch micro-pattern gas detector(Microbulk Micromegas)will be used at both ends of the TPC for the charge readout with a cathode in the middle.Charge signals can be used to reconstruct the electron tracks of the NLDBD events and provide good energy and spatial resolution.The detector will be immersed in a large water tank to ensure～5 m of water shielding in all directions.The second phase,a ton-scale experiment,will consist of five TPCs in the same water tank,with improved energy resolution and better control over backgrounds.
基金supported by the National Key Basic Research Program of China(Grant No.2013CB834402)the National Natural Science Foundation of China(Grant Nos.11235001,11320101004,and 11575007)the China-U.S.Theory Institute for Physics with Exotic Nuclei(CUSTIPEN)funded by the U.S.Department of Energy,Office of Science(Grant No.DESC0009971)
文摘β-decay properties of N=18-22,Z=10-14 nuclei are analyzed with a new shell-model Hamiltonian using the Gogny densitydependent interaction.The Gogny force which has been widely and successfully used in mean-field theory can provide reasonable two-body matrix elements for cross-shell calculations.The log f t values andβ-decay level schemes are systematically studied using the D1S-Gogny interaction and compared with the SDPF-M results and experimental data.It is shown that the new Hamiltonian provides reliable results forβ-decay along with subtle level schemes for this region.Shell-model calculations with Gogny interaction can lead to a successful description of nuclei in and around the N=20 island of inversion and supplements experiment where sufficient data are not available.
文摘In this work, the ft values of the 0+ →0+ superallowed Fermi beta decays have been investigated. In the calculations, the shell model has been modified by Pyatov's restoration method because of the isospin breaking and the transition matrix elements have been found by means of the quasi-particle random phase approximation (QRPA).
