The ground-state mass excess of the T_(z)=−2 drip-line nucleus ^(22)Al is measured for the first time as 18103(10)keV using the newly-developed Bρ-defined isochronous mass spectrometry method at the cooler storage ri...The ground-state mass excess of the T_(z)=−2 drip-line nucleus ^(22)Al is measured for the first time as 18103(10)keV using the newly-developed Bρ-defined isochronous mass spectrometry method at the cooler storage ring in Lanzhou.The new mass excess value allowed us to determine the excitation energies of the two low-lying 1+states in ^(22)Al with significantly reduced uncertainties of 51 keV.When compared to the analogue states in its mirror nucleus ^(22)F,the mirror energy differences of the two 1^(+)states in the ^(22)Al-^(22)F mirror pair are determined to be−625(51)keV and−330(51)keV.The excitation energies and mirror energy differences are used to test the state-of-the-art ab initio valence-space in-medium similarity renormalization group calculations with four sets of interactions derived from the chiral effective field theory.The mechanism leading to the large mirror energy differences is investigated and attributed to the occupation of theπs_(1/2) orbital.展开更多
Isochronous mass spectrometry in storage rings is a successful technique for the precision mass measurements ofthe nuclides with half-lives down to tens of microseconds[1]. Since the isochronous condition =t greatly r...Isochronous mass spectrometry in storage rings is a successful technique for the precision mass measurements ofthe nuclides with half-lives down to tens of microseconds[1]. Since the isochronous condition =t greatly reducesthe influence of the velocity difference on the ion revolution periods, the revolution period difference ΔT =T ??TRof a stored ion with respect to a reference time TR is directly related to its mass-to-charge ratio difference Δ(m=q),written in the first order as:展开更多
The masses of neutron-defcient nuclides play a critical role in the calculation of astrophysical rapid proton-capture processes[1].Neutron-defcient nuclides with mass number∧around 80 are the last set of nuclides wit...The masses of neutron-defcient nuclides play a critical role in the calculation of astrophysical rapid proton-capture processes[1].Neutron-defcient nuclides with mass number∧around 80 are the last set of nuclides with unknown masses on the pathway of vp-process[2].The mass measurement of nuclides would be very useful.In 2016,masses of neutron-defcient nuclides 79Y,81Zr,82Zr,83Nb and 84Nb nuclei were precisely measured directly by the experimental storage-ring CSRe at Lanzhou.展开更多
Mass is one of the fundamental properties of atomic nuclei. Isochronous mass spectrometry (IMS), using astorage ring combined with an in-flight separator, has been shown to be a powerful tool for mass measurementof ex...Mass is one of the fundamental properties of atomic nuclei. Isochronous mass spectrometry (IMS), using astorage ring combined with an in-flight separator, has been shown to be a powerful tool for mass measurementof exotic nuclei[1]. Recently, masses of many proton-rich nuclides were accurately determined at the HIRFL-CSRfacility[2]. In this paper, we described the first isochronous mass measurement of neutron-rich nuclides at CSRe.This experiment was performed at the end of 2011. In the experiment, the primary beam of 86Kr28+ ions wasaccumulated and accelerated to an energy of 460.65 MeV/u in the synchrotron CSRm. The 86Kr28+ ions were fastextracted and focused on a 15 mm thick beryllium target which was placed at the entrance of the RIBLL2 (anin-flight fragment separator).展开更多
Precision mass measurements of neutron-deficient 152Sm projectile fragments were conducted in 2005 at theFRS-ESR facility at GSI Helmholtz centre[1, 2], employing the time-resolved Schottky Mass Spectrometry[3]. A new...Precision mass measurements of neutron-deficient 152Sm projectile fragments were conducted in 2005 at theFRS-ESR facility at GSI Helmholtz centre[1, 2], employing the time-resolved Schottky Mass Spectrometry[3]. A newmass evaluation method has been developed in the data analysis. The systematic error in the mass determinationwas significantly reduced with the new method[4].Exotic nuclei, produced by projectile fragmentation of a 615 AMeV 152Sm primary beam in a 4.009 g/cm2beryllium target, were transmitted and B-separated by the fragment separator FRS and then injected and storedin the experimental storage ring ESR. In ESR the electron-cooling process was continuously applied to the storedions. To first order approximation, the revolution-frequencies (f) of the stored ions in the ESR are related to theirvelocities (v) and mass-to-charge ratios (m=q) of the ions in rest frame:展开更多
In conventional isochronous mass spectrometry (IMS), single time-of-flight (TOF) method is adopted to measurethe ions' revolution times in a storage ring which can then be used to calculate the ions' masses. H...In conventional isochronous mass spectrometry (IMS), single time-of-flight (TOF) method is adopted to measurethe ions' revolution times in a storage ring which can then be used to calculate the ions' masses. However, themass-to-charge ratio (m=q) is only related to the revolution time (T) under the condition that is equal to taccording to the following equation:展开更多
基金Supported in part by the Strategic Priority Research Program of Chinese Academy of Sciences (XDB34000000)the CAS Project for Young Scientists in Basic Research (YSBR-002)+4 种基金the National Nature Science Foundation of China (12135017,12121005,11975280,12105333,12205340,12322507,12305126,12305151)the Gansu Natural Science Foundation (22JR5RA123,23JRRA614)the National Key R&D Program of China (2021YFA1601500)Support from the Youth Innovation Promotion Association of Chinese Academy of Sciences (2021419,2022423)support from Young Scholar of Regional Development,CAS ([2023]15).
文摘The ground-state mass excess of the T_(z)=−2 drip-line nucleus ^(22)Al is measured for the first time as 18103(10)keV using the newly-developed Bρ-defined isochronous mass spectrometry method at the cooler storage ring in Lanzhou.The new mass excess value allowed us to determine the excitation energies of the two low-lying 1+states in ^(22)Al with significantly reduced uncertainties of 51 keV.When compared to the analogue states in its mirror nucleus ^(22)F,the mirror energy differences of the two 1^(+)states in the ^(22)Al-^(22)F mirror pair are determined to be−625(51)keV and−330(51)keV.The excitation energies and mirror energy differences are used to test the state-of-the-art ab initio valence-space in-medium similarity renormalization group calculations with four sets of interactions derived from the chiral effective field theory.The mechanism leading to the large mirror energy differences is investigated and attributed to the occupation of theπs_(1/2) orbital.
文摘Isochronous mass spectrometry in storage rings is a successful technique for the precision mass measurements ofthe nuclides with half-lives down to tens of microseconds[1]. Since the isochronous condition =t greatly reducesthe influence of the velocity difference on the ion revolution periods, the revolution period difference ΔT =T ??TRof a stored ion with respect to a reference time TR is directly related to its mass-to-charge ratio difference Δ(m=q),written in the first order as:
文摘The masses of neutron-defcient nuclides play a critical role in the calculation of astrophysical rapid proton-capture processes[1].Neutron-defcient nuclides with mass number∧around 80 are the last set of nuclides with unknown masses on the pathway of vp-process[2].The mass measurement of nuclides would be very useful.In 2016,masses of neutron-defcient nuclides 79Y,81Zr,82Zr,83Nb and 84Nb nuclei were precisely measured directly by the experimental storage-ring CSRe at Lanzhou.
文摘Mass is one of the fundamental properties of atomic nuclei. Isochronous mass spectrometry (IMS), using astorage ring combined with an in-flight separator, has been shown to be a powerful tool for mass measurementof exotic nuclei[1]. Recently, masses of many proton-rich nuclides were accurately determined at the HIRFL-CSRfacility[2]. In this paper, we described the first isochronous mass measurement of neutron-rich nuclides at CSRe.This experiment was performed at the end of 2011. In the experiment, the primary beam of 86Kr28+ ions wasaccumulated and accelerated to an energy of 460.65 MeV/u in the synchrotron CSRm. The 86Kr28+ ions were fastextracted and focused on a 15 mm thick beryllium target which was placed at the entrance of the RIBLL2 (anin-flight fragment separator).
文摘Precision mass measurements of neutron-deficient 152Sm projectile fragments were conducted in 2005 at theFRS-ESR facility at GSI Helmholtz centre[1, 2], employing the time-resolved Schottky Mass Spectrometry[3]. A newmass evaluation method has been developed in the data analysis. The systematic error in the mass determinationwas significantly reduced with the new method[4].Exotic nuclei, produced by projectile fragmentation of a 615 AMeV 152Sm primary beam in a 4.009 g/cm2beryllium target, were transmitted and B-separated by the fragment separator FRS and then injected and storedin the experimental storage ring ESR. In ESR the electron-cooling process was continuously applied to the storedions. To first order approximation, the revolution-frequencies (f) of the stored ions in the ESR are related to theirvelocities (v) and mass-to-charge ratios (m=q) of the ions in rest frame:
文摘In conventional isochronous mass spectrometry (IMS), single time-of-flight (TOF) method is adopted to measurethe ions' revolution times in a storage ring which can then be used to calculate the ions' masses. However, themass-to-charge ratio (m=q) is only related to the revolution time (T) under the condition that is equal to taccording to the following equation:
