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
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(IMS)at heavy-ion rings is a powerful tool for precision mass measurements of short-lived nuclei.In the conventional IMS,the masses are determined through precision measurements of revolut...Isochronous mass spectrometry(IMS)at heavy-ion rings is a powerful tool for precision mass measurements of short-lived nuclei.In the conventional IMS,the masses are determined through precision measurements of revolution times.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
At a certain high temperature,this cycle will be dominant and end the rp-process to heavier region[2].It provides an upper temperature limit for rp-process along the proton drip line to produce nuclides beyond A=84,in...At a certain high temperature,this cycle will be dominant and end the rp-process to heavier region[2].It provides an upper temperature limit for rp-process along the proton drip line to produce nuclides beyond A=84,including the light p nuclides of 92;94Mo,96;94Ru.The existence of Zr-Nb cycle is an important question in rp-process[2].α-separation energy(Sα)of 84Mo plays an important role in the formation of this cycle.A strong enhancement of 83Nb(p,α)reaction rate is due to a very low Sαof 84Mo[1].展开更多
We have reported the mass measurements of neutron-deficient nuclides 79Y,81;82Zr,83;84Nb in this year’s Annual Report.However,for the N=Z nuclides close to A=80,the yield is much lower and even if they can be produce...We have reported the mass measurements of neutron-deficient nuclides 79Y,81;82Zr,83;84Nb in this year’s Annual Report.However,for the N=Z nuclides close to A=80,the yield is much lower and even if they can be produced,there is still great difficult to identify them because of their quite similar mass-to-charge ratio and revolution times.However,their mass are extremely important for rapid proton capture process,for example,80Zr and 84Mo are waiting points of rp-process.Their masses can greatly effect the reaction flow of proton capture on them and then the abundance of the heavier nuclides.In addition,the separation energy of 84Mo(determined by the mass of 80Zr and 84Mo)has a strong impact on the 83Nb(p,α)reaction rate and plays a key role in the formation of Zr-Nb Fig.展开更多
Nuclear mass is one of the fundamental quantity of atomic nucleus.The total binding energy of a nucleus derived from the related mass values reflects all the interactions among the constituting nucleons.Masses of shor...Nuclear mass is one of the fundamental quantity of atomic nucleus.The total binding energy of a nucleus derived from the related mass values reflects all the interactions among the constituting nucleons.Masses of short-lived A=2Z+3 nuclei of 112Sn projectile fragments have been measured at the experimental cooler storage ring CSRe,employing the Isochronous mass spectrometry(IMS).The experiment was conducted at the Heavy Ion Research Facility in Lanzhou at the beginning of 2016.The primary beam of 112Sn35+was accumulated in the synchrotron CSRm and accelerated to 467.91 MeV/u.Secondary beam were produced by impinging the high intensity 112Sn35+beam onto a 10 mm beryllium target which was located at the entrance of the radioactive beam line RIBLL2.The projectile fragments of 112Sn emerged from the target were then transmitted,separated in flight through RIBLL2 and finally injected into CSRe.展开更多
基于兰州重离子研究装置冷却储存环(HIRFL-CSR)发展了等时性质谱术(Isochronous mass spectrometry,IMS),高精度测量了一批短寿命原子核的质量并研究了核结构和核天体领域的相关物理问题。本文综述了IMS实验的原理和步骤,重点介绍了目...基于兰州重离子研究装置冷却储存环(HIRFL-CSR)发展了等时性质谱术(Isochronous mass spectrometry,IMS),高精度测量了一批短寿命原子核的质量并研究了核结构和核天体领域的相关物理问题。本文综述了IMS实验的原理和步骤,重点介绍了目前正在发展的双TOF探测器谱仪。利用双TOF质量谱仪在测量离子回旋周期的同时测量了离子的速度,用来修正实验结果,可以在很宽的动量接收度内实现高质量分辨,并消除离子动量分散带来的系统误差。双TOF等时性质谱术是全新的概念,需要针对性开发相关实验技术。我们建立了基于CSRe的模拟平台,研制了高性能TOF探测器并安装在CSRe直线段,进行了在线束流测试,发展了新的束流光学设置并进行优化,开发了实验数据处理方法并在做进一步优化,并对下一步工作进行了展望。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:
基金National Key R&D Program of China(2018YFA0404401)。
文摘Isochronous mass spectrometry(IMS)at heavy-ion rings is a powerful tool for precision mass measurements of short-lived nuclei.In the conventional IMS,the masses are determined through precision measurements of revolution times.
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At a certain high temperature,this cycle will be dominant and end the rp-process to heavier region[2].It provides an upper temperature limit for rp-process along the proton drip line to produce nuclides beyond A=84,including the light p nuclides of 92;94Mo,96;94Ru.The existence of Zr-Nb cycle is an important question in rp-process[2].α-separation energy(Sα)of 84Mo plays an important role in the formation of this cycle.A strong enhancement of 83Nb(p,α)reaction rate is due to a very low Sαof 84Mo[1].
文摘We have reported the mass measurements of neutron-deficient nuclides 79Y,81;82Zr,83;84Nb in this year’s Annual Report.However,for the N=Z nuclides close to A=80,the yield is much lower and even if they can be produced,there is still great difficult to identify them because of their quite similar mass-to-charge ratio and revolution times.However,their mass are extremely important for rapid proton capture process,for example,80Zr and 84Mo are waiting points of rp-process.Their masses can greatly effect the reaction flow of proton capture on them and then the abundance of the heavier nuclides.In addition,the separation energy of 84Mo(determined by the mass of 80Zr and 84Mo)has a strong impact on the 83Nb(p,α)reaction rate and plays a key role in the formation of Zr-Nb Fig.
文摘Nuclear mass is one of the fundamental quantity of atomic nucleus.The total binding energy of a nucleus derived from the related mass values reflects all the interactions among the constituting nucleons.Masses of short-lived A=2Z+3 nuclei of 112Sn projectile fragments have been measured at the experimental cooler storage ring CSRe,employing the Isochronous mass spectrometry(IMS).The experiment was conducted at the Heavy Ion Research Facility in Lanzhou at the beginning of 2016.The primary beam of 112Sn35+was accumulated in the synchrotron CSRm and accelerated to 467.91 MeV/u.Secondary beam were produced by impinging the high intensity 112Sn35+beam onto a 10 mm beryllium target which was located at the entrance of the radioactive beam line RIBLL2.The projectile fragments of 112Sn emerged from the target were then transmitted,separated in flight through RIBLL2 and finally injected into CSRe.
文摘基于兰州重离子研究装置冷却储存环(HIRFL-CSR)发展了等时性质谱术(Isochronous mass spectrometry,IMS),高精度测量了一批短寿命原子核的质量并研究了核结构和核天体领域的相关物理问题。本文综述了IMS实验的原理和步骤,重点介绍了目前正在发展的双TOF探测器谱仪。利用双TOF质量谱仪在测量离子回旋周期的同时测量了离子的速度,用来修正实验结果,可以在很宽的动量接收度内实现高质量分辨,并消除离子动量分散带来的系统误差。双TOF等时性质谱术是全新的概念,需要针对性开发相关实验技术。我们建立了基于CSRe的模拟平台,研制了高性能TOF探测器并安装在CSRe直线段,进行了在线束流测试,发展了新的束流光学设置并进行优化,开发了实验数据处理方法并在做进一步优化,并对下一步工作进行了展望。
