Atomic nuclei are many body systems composed of quantum particles termed nucleons,which are either positively charged protons or electrically neutral neutrons.The nuclear force,which describes interactions between nuc...Atomic nuclei are many body systems composed of quantum particles termed nucleons,which are either positively charged protons or electrically neutral neutrons.The nuclear force,which describes interactions between nucleons,is highly complicated.On the microscopic scale,it determines the structure of nuclei,the limits of their existence,their excitations,decay probabilities,reaction dynamics,etc.[1].On the macroscopic scale,it decides upon the composition of compact cosmic objects and governs various processes in stellar environments[2].In spite of the centurylong perpetual investigations,the comprehension of the nuclear force is far from being complete.展开更多
In this paper, we present direct mass measurements of neutron-rich86 Kr projectile fragments conducted at the HIRFL-CSR facility in Lanzhou by employing the Isochronous Mass Spectrometry(IMS) method. The new mass exce...In this paper, we present direct mass measurements of neutron-rich86 Kr projectile fragments conducted at the HIRFL-CSR facility in Lanzhou by employing the Isochronous Mass Spectrometry(IMS) method. The new mass excesses of52-54 Sc nuclides are determined to be-40492(82),-38928(114),-34654(540) ke V, which show a significant increase of binding energy compared to the reported ones in the Atomic Mass Evaluation 2012(AME12).In particular,53 Sc and54Sc are more bound by 0.8 Me V and 1.0 Me V, respectively. The behavior of the two neutron separation energy with neutron numbers indicates a strong sub-shell closure at neutron number N =32 in Sc isotopes.展开更多
The concept of isochronous mass spectrometry(IMS) applying two time-of-flight(TOF) detectors originated many years ago at GSI. However, the corresponding method for data analysis has never been discussed in detail. Re...The concept of isochronous mass spectrometry(IMS) applying two time-of-flight(TOF) detectors originated many years ago at GSI. However, the corresponding method for data analysis has never been discussed in detail. Recently, two TOF detectors have been installed at CSRe and the new working mode of the ring is under test. In this paper, a data analysis method for this mode is introduced and tested with a series of simulations. The results show that the new IMS method can significantly improve mass resolving power via the additional velocity information of stored ions. This improvement is especially important for nuclides with Lorentz factor γ-value far away from the transition point γt of the storage ring CSRe.展开更多
基金supported in part by the National Key R&D Program of China(2018YFA0404401)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB34000000)+1 种基金the National Natural Science Foundation of China(12135017 and12121005)the State of Hesse within the Research Cluster ELEMENTS(Project ID 500/10.006)。
文摘Atomic nuclei are many body systems composed of quantum particles termed nucleons,which are either positively charged protons or electrically neutral neutrons.The nuclear force,which describes interactions between nucleons,is highly complicated.On the microscopic scale,it determines the structure of nuclei,the limits of their existence,their excitations,decay probabilities,reaction dynamics,etc.[1].On the macroscopic scale,it decides upon the composition of compact cosmic objects and governs various processes in stellar environments[2].In spite of the centurylong perpetual investigations,the comprehension of the nuclear force is far from being complete.
基金Supported by 973 Program of China(2013CB834401)the NSFC(U1232208,U1432125,11205205,11035007)the Helmholtz-CAS Joint Research Group(HCJRG-108)
文摘In this paper, we present direct mass measurements of neutron-rich86 Kr projectile fragments conducted at the HIRFL-CSR facility in Lanzhou by employing the Isochronous Mass Spectrometry(IMS) method. The new mass excesses of52-54 Sc nuclides are determined to be-40492(82),-38928(114),-34654(540) ke V, which show a significant increase of binding energy compared to the reported ones in the Atomic Mass Evaluation 2012(AME12).In particular,53 Sc and54Sc are more bound by 0.8 Me V and 1.0 Me V, respectively. The behavior of the two neutron separation energy with neutron numbers indicates a strong sub-shell closure at neutron number N =32 in Sc isotopes.
基金Supported by the 973 Program of China(2013CB834401)National Nature Science Foundation of China(U1232208,U1432125,11205205,11035007)the Helmholtz-CAS Joint Research Group(Group No.HCJRG-108)
文摘The concept of isochronous mass spectrometry(IMS) applying two time-of-flight(TOF) detectors originated many years ago at GSI. However, the corresponding method for data analysis has never been discussed in detail. Recently, two TOF detectors have been installed at CSRe and the new working mode of the ring is under test. In this paper, a data analysis method for this mode is introduced and tested with a series of simulations. The results show that the new IMS method can significantly improve mass resolving power via the additional velocity information of stored ions. This improvement is especially important for nuclides with Lorentz factor γ-value far away from the transition point γt of the storage ring CSRe.
