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
Recent results and progress of mass measurements of neutron-rich nuclei utilizing Isochronous Mass Spectrometry(IMS) based on the HIRFL-CSR complex at Lanzhou are reported. The nuclei of interest were produced through...Recent results and progress of mass measurements of neutron-rich nuclei utilizing Isochronous Mass Spectrometry(IMS) based on the HIRFL-CSR complex at Lanzhou are reported. The nuclei of interest were produced through projectile fragmentation of primary86 Kr ions at a realistic energy of460.65 Me V/u. After in-flight separation by the fragment separator RIBLL2, the fragments were injected and stored in the experimental storage ring CSRe, and their masses were determined from measurements of their revolution times. The re-determined masses were compared and evaluated with other mass measurements, and the impact of these evaluated masses on the shell evolution study is discussed.展开更多
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
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National Basic Research Program of China(973 Program)(2013CB834401)National Natural Science Foundation of China(U1232208,U1432125,11205205,11035007)Western Light Talent Training Program of Chinese Academy Scienus
文摘Recent results and progress of mass measurements of neutron-rich nuclei utilizing Isochronous Mass Spectrometry(IMS) based on the HIRFL-CSR complex at Lanzhou are reported. The nuclei of interest were produced through projectile fragmentation of primary86 Kr ions at a realistic energy of460.65 Me V/u. After in-flight separation by the fragment separator RIBLL2, the fragments were injected and stored in the experimental storage ring CSRe, and their masses were determined from measurements of their revolution times. The re-determined masses were compared and evaluated with other mass measurements, and the impact of these evaluated masses on the shell evolution study is discussed.
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.
