In this paper, we present direct mass measurements of neutron-rich S6Kr projectile fragments conducted at the HIRFL-CSR facility in Lanzhou by employing the Isochronous Mass Spectrometry （IMS） method. The new mass e...In this paper, we present direct mass measurements of neutron-rich S6Kr projectile fragments conducted at the HIRFL-CSR facility in Lanzhou by employing the Isochronous Mass Spectrometry （IMS） method. The new mass excesses of ^52-54Sc nuclides are determined to be -40492（82）, -38928（114）, -34654（540） keV, which show a significant increase of binding energy compared to the reported ones in the Atomic Mass Evaluation 2012 （AME12）. In particular, ^53Sc and ^54sc are more bound by 0.8 MeV and 1.0 MeV, 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
原子质量评估(Atomic Mass Evaluation,AME)是一项收集和综合评价与原子质量相关(例如质谱术、衰变和核反应等)实验数据的重要工作,它被广泛认为是国际上权威可靠的原子质量信息来源。随着质量测量技术的不断发展,不仅测量的精度得到了...原子质量评估(Atomic Mass Evaluation,AME)是一项收集和综合评价与原子质量相关(例如质谱术、衰变和核反应等)实验数据的重要工作,它被广泛认为是国际上权威可靠的原子质量信息来源。随着质量测量技术的不断发展,不仅测量的精度得到了显著提高,而且可测核素的范围也得到了扩大,同时揭示了许多奇特原子核的新现象。精确的质量数据为原子核结构、原子核反应以及核天体物理等基础核物理研究领域提供了不可或缺的参考。本工作对最新出版的原子质量数据评估AME2020进行了概述,并对当前主要质量测量实验装置的精度进行了检验,同时举例说明了重要实验数据。AME2020的发布对于广泛的科学研究和技术应用领域具有深远的实际影响。展开更多
With the development of radioactive-ion-beam facilities,many exotic phenomena have been discovered or predicted in the nuclei far from the stability line,including cluster structure,shell structure,deformed halo,and s...With the development of radioactive-ion-beam facilities,many exotic phenomena have been discovered or predicted in the nuclei far from the stability line,including cluster structure,shell structure,deformed halo,and shape decoupling effects.The study of exotic nuclear phenomena is at the frontier of nuclear physics nowadays.The covariant density functional theory(CDFT)is one of the most successful microscopic models in describing the structure of nuclei in almost the whole nuclear chart.Within the framework of CDFT,toward a proper treatment of deformation and weak binding,the deformed relativistic Hartree-Bogoliubov theory in continuum(DRHBc)has been developed.In this contribution,we review the applications and extensions of the DRHBc theory to the study of exotic nuclei.The DRHBc theory has been used to investigate the deformed halos in B,C,Ne,Na,and Mg isotopes and the theoretical descriptions are reasonably consistent with available data.A DRHBc Mass Table Collaboration has been founded,aiming at a high precision nuclear mass table with deformation and continuum effects included,which is underway.By implementing the angular momentum projection based on the DRHBc theory,the rotational excitations of deformed halos have been investigated and it is shown that the deformed halos and shape decoupling effects also exist in the low-lying rotational excitation states of deformed halo nuclei.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 deta...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 yt of the storage ring CSRe.展开更多
Knockout reaction experiment was carried out by using the 6He beams at 61.2 MeV/u impinging on a CH2 target. The α core fragments at forward angles were detected in coincidence with the recoiled protons at larger ang...Knockout reaction experiment was carried out by using the 6He beams at 61.2 MeV/u impinging on a CH2 target. The α core fragments at forward angles were detected in coincidence with the recoiled protons at larger angles. From this exclusive meas urement the valence nucleon knockout mechanism and the core knockout mechanism can be distinguished by the relation be tween the polar angles of the core fragments and the recoiled protons, respectively. It is demonstrated that the core knockout mechanism may result in some strong contamination to the real invariant mass spectrum.展开更多
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-rich S6Kr projectile fragments conducted at the HIRFL-CSR facility in Lanzhou by employing the Isochronous Mass Spectrometry （IMS） method. The new mass excesses of ^52-54Sc nuclides are determined to be -40492（82）, -38928（114）, -34654（540） keV, which show a significant increase of binding energy compared to the reported ones in the Atomic Mass Evaluation 2012 （AME12）. In particular, ^53Sc and ^54sc are more bound by 0.8 MeV and 1.0 MeV, 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.
文摘原子质量评估(Atomic Mass Evaluation,AME)是一项收集和综合评价与原子质量相关(例如质谱术、衰变和核反应等)实验数据的重要工作,它被广泛认为是国际上权威可靠的原子质量信息来源。随着质量测量技术的不断发展,不仅测量的精度得到了显著提高,而且可测核素的范围也得到了扩大,同时揭示了许多奇特原子核的新现象。精确的质量数据为原子核结构、原子核反应以及核天体物理等基础核物理研究领域提供了不可或缺的参考。本工作对最新出版的原子质量数据评估AME2020进行了概述,并对当前主要质量测量实验装置的精度进行了检验,同时举例说明了重要实验数据。AME2020的发布对于广泛的科学研究和技术应用领域具有深远的实际影响。
文摘With the development of radioactive-ion-beam facilities,many exotic phenomena have been discovered or predicted in the nuclei far from the stability line,including cluster structure,shell structure,deformed halo,and shape decoupling effects.The study of exotic nuclear phenomena is at the frontier of nuclear physics nowadays.The covariant density functional theory(CDFT)is one of the most successful microscopic models in describing the structure of nuclei in almost the whole nuclear chart.Within the framework of CDFT,toward a proper treatment of deformation and weak binding,the deformed relativistic Hartree-Bogoliubov theory in continuum(DRHBc)has been developed.In this contribution,we review the applications and extensions of the DRHBc theory to the study of exotic nuclei.The DRHBc theory has been used to investigate the deformed halos in B,C,Ne,Na,and Mg isotopes and the theoretical descriptions are reasonably consistent with available data.A DRHBc Mass Table Collaboration has been founded,aiming at a high precision nuclear mass table with deformation and continuum effects included,which is underway.By implementing the angular momentum projection based on the DRHBc theory,the rotational excitations of deformed halos have been investigated and it is shown that the deformed halos and shape decoupling effects also exist in the low-lying rotational excitation states of deformed halo nuclei.
基金partly supported by the National Natural Science Foundation of China(NSFC,12035007)Guangdong Provincial funding(2019QN01X172)+4 种基金Guangdong Major Project of Basic and Applied Basic Research(2020B0301030008)supported by the NSFC(12070131001)the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation,Project-ID 196253076-TRR110)through the funds provided to the Sino-German Collaborative Research Center TRR110"Symmetries and the Emergence of Structure in QCD"supported by the Chinese Academy of Sciences(CAS)President’s International Fellowship Initiative(PIFI)(2018DM0034)Volkswagen Stiftung(93562)。
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 yt of the storage ring CSRe.
基金supported by the National Basic Research Program of China (Grant No. 2007CB815002)the National Natural Science Foundation of China (Grant Nos. 11035001, 10775003, 10821140159 and J0730316)the Fundamental Research Funds for the Central Universi-ties of China
文摘Knockout reaction experiment was carried out by using the 6He beams at 61.2 MeV/u impinging on a CH2 target. The α core fragments at forward angles were detected in coincidence with the recoiled protons at larger angles. From this exclusive meas urement the valence nucleon knockout mechanism and the core knockout mechanism can be distinguished by the relation be tween the polar angles of the core fragments and the recoiled protons, respectively. It is demonstrated that the core knockout mechanism may result in some strong contamination to the real invariant mass spectrum.
