Nuclear mass measurements provide valuable information on the nuclear binding energy which reflects the summed result of all interactions among its constituent protons and neutrons. The systematic and accurate knowled...Nuclear mass measurements provide valuable information on the nuclear binding energy which reflects the summed result of all interactions among its constituent protons and neutrons. The systematic and accurate knowledge of nuclear masses have wide application in many areas of subatomic physics ranging from nuclear structure and astrophysics to the fundamental interactions and symmetries depending on the achieved mass precision[1].展开更多
Isochronous mass spectrometry (IMS) in storage rings is a powerful tool for mass measurements of exotic nucle with very short half-lives down to several tens of microseconds, using a multicomponent secondary beam sepa...Isochronous mass spectrometry (IMS) in storage rings is a powerful tool for mass measurements of exotic nucle with very short half-lives down to several tens of microseconds, using a multicomponent secondary beam separated in-ight without cooling. However, the inevitable momentum spread of secondary ions limits the precision of nuclear masses determined by using IMS.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
A radioactive nucleus is characterized with an intrinsic half-life. However, for a nuclear species, the half-lives inneutral atoms could be very different from that in highly charged ions. The half-lives of some highl...A radioactive nucleus is characterized with an intrinsic half-life. However, for a nuclear species, the half-lives inneutral atoms could be very different from that in highly charged ions. The half-lives of some highly charged ionshave been directly measured at GSI for multiple motivations[1]. In the same case, the nuclear state(i:e the isomer)may be in the range of several tens of microseconds and their half-live can be measured using isochronous massspectrometry. The J = 8+ isomeric state in 94Ru was chosen to test this method. The half-life of this isomer is71 s [2] in neutral atoms, and the excitation energy is 2.64 MeV. The internal conversion coefficient of this decayin neutral atom is 0.335. So its half-life in the bare nucleus would be modified to be 94.78 s when the internalconversion channel is blocked.展开更多
Until now, several isochronous mass spectrometry (IMS) experiments have been successfully performed usingvarious primary beams at the HIRFL-CSR and masses of both proton-rich and proton-deficient exotic nuclei havebee...Until now, several isochronous mass spectrometry (IMS) experiments have been successfully performed usingvarious primary beams at the HIRFL-CSR and masses of both proton-rich and proton-deficient exotic nuclei havebeen measured. In order to improve the performance of the IMS experiments and to provide a reliable tool fordesigning and preparing the future experiments, a simulation code, named SimCSR is developed.Presently, six-dimension phase-space linear transmission theory is applied to simulate the transmission of ionsin the experimental storage ring (CSRe). The basic algorithm is Bf = MBi. The Bi and Bf are six-dimensionphase-space vectors of ions at the entrance and exit of each element of the CSRe lattice, respectively. M is a6-by-6-dimension first-order transfer matrix of each element. M is calculated using formulas described in Ref.[1]. Inthe simulations, the ring lattice is considered in detail, and the same magnetic setting as in our previous experimentwith 58Ni projectile fragments[2] is considered. The ions are assumed to circulate 300 turns inside the CSRe.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
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 stability of the magnetic fields is of vital importance to the success of the precision experiments conducted in the experimental Cooler Storage Ring(CSRe)in Lanzhou.In the CSRe,the electromagnets are cooled using...The stability of the magnetic fields is of vital importance to the success of the precision experiments conducted in the experimental Cooler Storage Ring(CSRe)in Lanzhou.In the CSRe,the electromagnets are cooled using room-temperature water.We monitored the magnetic field strength B of one of the dipole magnets,as well as the DC current I of the power supply and the temperature T of the cooling water for a long term.展开更多
Nuclear mass and half-life measurements are important research projects at the CSRe storage ring.The progress is summarized below.The data analyses are now nished for the 6th traditional IMS experiment with ^(112)Sn f...Nuclear mass and half-life measurements are important research projects at the CSRe storage ring.The progress is summarized below.The data analyses are now nished for the 6th traditional IMS experiment with ^(112)Sn fragments(2016)and the 6th Bρ-IMS experiment with 78Kr fragments(2020).展开更多
Exotic decay modes of highly charged radioactive ions^([1])is one of the research subjects at the experimental Storage Ring CSRe in Lanzhou.In order to measure the nuclear decay half-life of the radioactive ions,the s...Exotic decay modes of highly charged radioactive ions^([1])is one of the research subjects at the experimental Storage Ring CSRe in Lanzhou.In order to measure the nuclear decay half-life of the radioactive ions,the storage ring should have a high preservation ability for ions,i.e.long enough storage lifetime of the highly charge ions.In the past few years,we have installed a new data acquisition system for the CSRe Schottky detector and measured the storage lifetimes of fully stripped ions in the CSRe under di erent conditions^([2]).The storage lifetimes of several ions were measured in successive experiments over the years.展开更多
In the isochronous mass spectrometry(IMS)[1]performed at storage rings,masses of short-lived nuclides are determined through precision measurements of their revolution time which has a relationship with the mass-tocha...In the isochronous mass spectrometry(IMS)[1]performed at storage rings,masses of short-lived nuclides are determined through precision measurements of their revolution time which has a relationship with the mass-tocharge ratio,m=q as following。展开更多
The stability of the magnetic fields is crucial for the precision experiments conducted at the experimental Cooler Storage Ring CSRe.From 2016,sudden changes of dB=B>10−4 of CSRe dipole magnetic fields happened irr...The stability of the magnetic fields is crucial for the precision experiments conducted at the experimental Cooler Storage Ring CSRe.From 2016,sudden changes of dB=B>10−4 of CSRe dipole magnetic fields happened irregularly which made the precision mass measurements at CSRe difficult to proceed.Therefore,a monitoring system have been built and the instabilities of the power supply and field strengths of the CSRe dipole magnets have been investigated in 2017.展开更多
The distance between two identical Time-Of-Flight(TOF)detectors,which are installed inside 10−11 mbar vacumm beam pipe in the straight section of the storage ring CSRe,is measured by a laser range-finder Leica Nova MS...The distance between two identical Time-Of-Flight(TOF)detectors,which are installed inside 10−11 mbar vacumm beam pipe in the straight section of the storage ring CSRe,is measured by a laser range-finder Leica Nova MS60 MultiStation[1].The objects of the measurement are the two carbon-foils of the detectors with their centres aligned to the ion beam trajectory.The diameter and thickness of the foils are 40 mm and90 nm respectively.Schematic view and picture of the TOF-detector[2]are shown in the left and middle panels of Fig.1.The TOFdetectors are moveable in x direction so that the carbon foil can be placed in and out of the beam line.展开更多
The chart of the nuclides is one of the basic tools in nuclear science and technology.We have designed a new two-dimensional chart of the nuclides,which displays up-to-date ground state nuclear properties such as isot...The chart of the nuclides is one of the basic tools in nuclear science and technology.We have designed a new two-dimensional chart of the nuclides,which displays up-to-date ground state nuclear properties such as isotopic abundances of stable nuclei,decay modes,half-lives of radioactive nuclei,atomic mass errors,and other experimental information extracted from the latest AME2020(Atomic Mass Evaluation)and NUBASE2020(evaluation of nuclear physics properties)^([1]).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
文摘Nuclear mass measurements provide valuable information on the nuclear binding energy which reflects the summed result of all interactions among its constituent protons and neutrons. The systematic and accurate knowledge of nuclear masses have wide application in many areas of subatomic physics ranging from nuclear structure and astrophysics to the fundamental interactions and symmetries depending on the achieved mass precision[1].
文摘Isochronous mass spectrometry (IMS) in storage rings is a powerful tool for mass measurements of exotic nucle with very short half-lives down to several tens of microseconds, using a multicomponent secondary beam separated in-ight without cooling. However, the inevitable momentum spread of secondary ions limits the precision of nuclear masses determined by using IMS.
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A radioactive nucleus is characterized with an intrinsic half-life. However, for a nuclear species, the half-lives inneutral atoms could be very different from that in highly charged ions. The half-lives of some highly charged ionshave been directly measured at GSI for multiple motivations[1]. In the same case, the nuclear state(i:e the isomer)may be in the range of several tens of microseconds and their half-live can be measured using isochronous massspectrometry. The J = 8+ isomeric state in 94Ru was chosen to test this method. The half-life of this isomer is71 s [2] in neutral atoms, and the excitation energy is 2.64 MeV. The internal conversion coefficient of this decayin neutral atom is 0.335. So its half-life in the bare nucleus would be modified to be 94.78 s when the internalconversion channel is blocked.
文摘Until now, several isochronous mass spectrometry (IMS) experiments have been successfully performed usingvarious primary beams at the HIRFL-CSR and masses of both proton-rich and proton-deficient exotic nuclei havebeen measured. In order to improve the performance of the IMS experiments and to provide a reliable tool fordesigning and preparing the future experiments, a simulation code, named SimCSR is developed.Presently, six-dimension phase-space linear transmission theory is applied to simulate the transmission of ionsin the experimental storage ring (CSRe). The basic algorithm is Bf = MBi. The Bi and Bf are six-dimensionphase-space vectors of ions at the entrance and exit of each element of the CSRe lattice, respectively. M is a6-by-6-dimension first-order transfer matrix of each element. M is calculated using formulas described in Ref.[1]. Inthe simulations, the ring lattice is considered in detail, and the same magnetic setting as in our previous experimentwith 58Ni projectile fragments[2] is considered. The ions are assumed to circulate 300 turns inside the CSRe.
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:
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:
基金CAS Young Scholar of Regional Development([2023]15)CAS Project for Young Scientists in Basic Research(YSBR-002)。
文摘The stability of the magnetic fields is of vital importance to the success of the precision experiments conducted in the experimental Cooler Storage Ring(CSRe)in Lanzhou.In the CSRe,the electromagnets are cooled using room-temperature water.We monitored the magnetic field strength B of one of the dipole magnets,as well as the DC current I of the power supply and the temperature T of the cooling water for a long term.
基金CAS Young Scholar of Regional Development([2023]15)CAS Project for Young Scientists in Basic Research(YSBR-002)+2 种基金National Key R&D Program of China(2018YFA0404401)Strategic Priority Research Program of Chinese Academy of Sciences(XDB34000000)National Natural Science Foundation of China(12135017,12121005)。
文摘Nuclear mass and half-life measurements are important research projects at the CSRe storage ring.The progress is summarized below.The data analyses are now nished for the 6th traditional IMS experiment with ^(112)Sn fragments(2016)and the 6th Bρ-IMS experiment with 78Kr fragments(2020).
基金CAS Project for Young Scientists in Basic Research(YSBR-002)National Key R&D Program of China(2018YFA0404401)+1 种基金Strategic Priority Research Program of Chinese Academy of Sciences(XDB34000000)National Natural Science Foundation of China(12135017,12121005)。
文摘Exotic decay modes of highly charged radioactive ions^([1])is one of the research subjects at the experimental Storage Ring CSRe in Lanzhou.In order to measure the nuclear decay half-life of the radioactive ions,the storage ring should have a high preservation ability for ions,i.e.long enough storage lifetime of the highly charge ions.In the past few years,we have installed a new data acquisition system for the CSRe Schottky detector and measured the storage lifetimes of fully stripped ions in the CSRe under di erent conditions^([2]).The storage lifetimes of several ions were measured in successive experiments over the years.
文摘In the isochronous mass spectrometry(IMS)[1]performed at storage rings,masses of short-lived nuclides are determined through precision measurements of their revolution time which has a relationship with the mass-tocharge ratio,m=q as following。
文摘The stability of the magnetic fields is crucial for the precision experiments conducted at the experimental Cooler Storage Ring CSRe.From 2016,sudden changes of dB=B>10−4 of CSRe dipole magnetic fields happened irregularly which made the precision mass measurements at CSRe difficult to proceed.Therefore,a monitoring system have been built and the instabilities of the power supply and field strengths of the CSRe dipole magnets have been investigated in 2017.
基金National Natural Science foundation of China(11605248,11605252)。
文摘The distance between two identical Time-Of-Flight(TOF)detectors,which are installed inside 10−11 mbar vacumm beam pipe in the straight section of the storage ring CSRe,is measured by a laser range-finder Leica Nova MS60 MultiStation[1].The objects of the measurement are the two carbon-foils of the detectors with their centres aligned to the ion beam trajectory.The diameter and thickness of the foils are 40 mm and90 nm respectively.Schematic view and picture of the TOF-detector[2]are shown in the left and middle panels of Fig.1.The TOFdetectors are moveable in x direction so that the carbon foil can be placed in and out of the beam line.
基金Young Scholar of Regional Development,CAS([2023]15)CAS Project for Young Scientists in Basic Research(YSBR-002)+2 种基金National Key R&D Program of China(2018YFA0404401)Strategic Priority Research Program of Chinese Academy of Sciences(XDB34000000)National Natural Science Foundation of China(12135017,12121005)。
文摘The chart of the nuclides is one of the basic tools in nuclear science and technology.We have designed a new two-dimensional chart of the nuclides,which displays up-to-date ground state nuclear properties such as isotopic abundances of stable nuclei,decay modes,half-lives of radioactive nuclei,atomic mass errors,and other experimental information extracted from the latest AME2020(Atomic Mass Evaluation)and NUBASE2020(evaluation of nuclear physics properties)^([1]).
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.
