Jinping Underground laboratory for Nuclear Astrophysics(JUNA) will take the advantage of the ultra-low background of CJPL lab and high current accelerator based on an ECR source and a highly sensitive detector to dire...Jinping Underground laboratory for Nuclear Astrophysics(JUNA) will take the advantage of the ultra-low background of CJPL lab and high current accelerator based on an ECR source and a highly sensitive detector to directly study for the first time a number of crucial reactions occurring at their relevant stellar energies during the evolution of hydrostatic stars. In its first phase, JUNA aims at the direct measurements of^(25)Mg(p,γ)^(26)Al,^(19)F(p,α)^(16)O,^(13)C(α,n)^(16)O and ^(12)C(α,γ)^(16)O reactions. The experimental setup,which includes an accelerator system with high stability and high intensity, a detector system, and a shielding material with low background, will be established during the above research. The current progress of JUNA will be given.展开更多
中国锦屏地下实验室是目前世界上岩石覆盖最深的深地实验室,对宇宙线μ子具有良好的屏蔽作用,具有极低的宇宙线通量,因此适用于开展对稀有物理事例的探测实验。目前,包括中国暗物质实验(China Dark matter EXperiment,CDEX)、粒子和天...中国锦屏地下实验室是目前世界上岩石覆盖最深的深地实验室,对宇宙线μ子具有良好的屏蔽作用,具有极低的宇宙线通量,因此适用于开展对稀有物理事例的探测实验。目前,包括中国暗物质实验(China Dark matter EXperiment,CDEX)、粒子和天体物理氙实验(Particle and Astrophysical Xenon Experiments,PandaX)、锦屏深地核天体物理实验装置(Jinping Underground Nuclear Astrophysics Experiment,JUNA)等实验组已经入驻锦屏实验室,对暗物质直接探测、无中微子双β衰变、天体核反应等一系列稀有物理事例进行实验探测,并给出了一系列国际先进水平的研究成果。本文总结了中国锦屏地下实验室自成立以来的发展过程和本底控制情况,并对实验室中各个实验组所开展实验的物理意义、实验原理、关键技术、物理成果等进行介绍,同时给出实验组接下来的实验计划。展开更多
Calcium production and the stellar evolution of first-generation stars remain fascinating mysteries in astrophysics.As one possible nucleosynthesis scenario,break-out from the hot carbon–nitrogen–oxygen(HCNO)cycle w...Calcium production and the stellar evolution of first-generation stars remain fascinating mysteries in astrophysics.As one possible nucleosynthesis scenario,break-out from the hot carbon–nitrogen–oxygen(HCNO)cycle was thought to be the source of the calcium observed in these oldest stars.However,according to the stellar modeling,a nearly tenfold increase in the thermonuclear rate ratio of the break-out ^(19)F(p,γ)^(20) Ne reaction with respect to the competing ^(19)F(p,α)^(16) O back-processing reaction is required to reproduce the observed calcium abundance.We performed a direct measurement of this break-out reaction at the China Jinping underground laboratory.The measurement was performed down to the low-energy limit of E_(c.m.)=186 keV in the center-of-mass frame.The key resonance was observed at 225.2 keV for the first time.At a temperature of approximately 0.1 GK,this new resonance enhanced the thermonuclear ^(19)F(p,γ)^(20) Ne rate by up to a factor of≈7.4,compared with the previously recommended NACRE rate.This is of particular interest to the study of the evolution of the first stars and implies a stronger breakdown in their“warm”CNO cycle through the ^(19)F(p,γ)^(20) Ne reaction than previously envisioned.This break-out resulted in the production of the calcium observed in the oldest stars,enhancing our understanding of the evolution of the first stars.展开更多
In 2014, the National Natural Science Foundation of China （NSFC） approved the Jinping Underground Nuclear Astrophysics laboratory （JUNA） project, which aims at direct cross-section measurements of four key stellar...In 2014, the National Natural Science Foundation of China （NSFC） approved the Jinping Underground Nuclear Astrophysics laboratory （JUNA） project, which aims at direct cross-section measurements of four key stellar nuclear reactions right down to the Gamow windows. In order to solve the observed fluorine overabundances in Asymptotic Giant Branch （AGB） stars, measuring the key 19F（p,a）16O reaction at effective burning energies （i.e., at Gamow window） is established as one of the scientific research sub-projects. The present paper describes this sub-project in details, including motivation, status, experimental setup, yield and background estimation, aboveground test, as well as other relevant reactions.展开更多
对锦屏深地核天体物理实验JUNA(Jinping Underground laboratory for Nuclear Astro-physics)离子源控制系统进行了研究,采用分布式系统模型构建。硬件采用PLC、串口服务器、伺服电机及工控机等部件实现了离子源设备的远程监测及控制。...对锦屏深地核天体物理实验JUNA(Jinping Underground laboratory for Nuclear Astro-physics)离子源控制系统进行了研究,采用分布式系统模型构建。硬件采用PLC、串口服务器、伺服电机及工控机等部件实现了离子源设备的远程监测及控制。软件通过建立EPICS IOC运行时数据库,实现了对所有被控设备的集成。用户操作界面采用CSS(Control System Studio)开发,实现了操作人员对所有被控设备的透明访问。基于安全连锁规则设计了机器保护系统,实现了运行异常下的连锁保护。该控制系统应用于国内首套深地实验强流ECR离子源,运行稳定可靠,完全满足JUNA运行及物理实验的需求。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11490560 and 11321064)the National Basic Research Program of China(Grant No.2013CB834406)
文摘Jinping Underground laboratory for Nuclear Astrophysics(JUNA) will take the advantage of the ultra-low background of CJPL lab and high current accelerator based on an ECR source and a highly sensitive detector to directly study for the first time a number of crucial reactions occurring at their relevant stellar energies during the evolution of hydrostatic stars. In its first phase, JUNA aims at the direct measurements of^(25)Mg(p,γ)^(26)Al,^(19)F(p,α)^(16)O,^(13)C(α,n)^(16)O and ^(12)C(α,γ)^(16)O reactions. The experimental setup,which includes an accelerator system with high stability and high intensity, a detector system, and a shielding material with low background, will be established during the above research. The current progress of JUNA will be given.
基金supported by the National Natural Science Foundation of China(Nos.12075027,1232509,11961141004,and 12175152)the National Science Foundation(Nos.Phys-2011890 and Phy-1430152)。
文摘Calcium production and the stellar evolution of first-generation stars remain fascinating mysteries in astrophysics.As one possible nucleosynthesis scenario,break-out from the hot carbon–nitrogen–oxygen(HCNO)cycle was thought to be the source of the calcium observed in these oldest stars.However,according to the stellar modeling,a nearly tenfold increase in the thermonuclear rate ratio of the break-out ^(19)F(p,γ)^(20) Ne reaction with respect to the competing ^(19)F(p,α)^(16) O back-processing reaction is required to reproduce the observed calcium abundance.We performed a direct measurement of this break-out reaction at the China Jinping underground laboratory.The measurement was performed down to the low-energy limit of E_(c.m.)=186 keV in the center-of-mass frame.The key resonance was observed at 225.2 keV for the first time.At a temperature of approximately 0.1 GK,this new resonance enhanced the thermonuclear ^(19)F(p,γ)^(20) Ne rate by up to a factor of≈7.4,compared with the previously recommended NACRE rate.This is of particular interest to the study of the evolution of the first stars and implies a stronger breakdown in their“warm”CNO cycle through the ^(19)F(p,γ)^(20) Ne reaction than previously envisioned.This break-out resulted in the production of the calcium observed in the oldest stars,enhancing our understanding of the evolution of the first stars.
基金supported by the National Natural Science Foundation of China(Grant Nos.114905621149056011135005 and 11321064)
文摘In 2014, the National Natural Science Foundation of China （NSFC） approved the Jinping Underground Nuclear Astrophysics laboratory （JUNA） project, which aims at direct cross-section measurements of four key stellar nuclear reactions right down to the Gamow windows. In order to solve the observed fluorine overabundances in Asymptotic Giant Branch （AGB） stars, measuring the key 19F（p,a）16O reaction at effective burning energies （i.e., at Gamow window） is established as one of the scientific research sub-projects. The present paper describes this sub-project in details, including motivation, status, experimental setup, yield and background estimation, aboveground test, as well as other relevant reactions.
文摘对锦屏深地核天体物理实验JUNA(Jinping Underground laboratory for Nuclear Astro-physics)离子源控制系统进行了研究,采用分布式系统模型构建。硬件采用PLC、串口服务器、伺服电机及工控机等部件实现了离子源设备的远程监测及控制。软件通过建立EPICS IOC运行时数据库,实现了对所有被控设备的集成。用户操作界面采用CSS(Control System Studio)开发,实现了操作人员对所有被控设备的透明访问。基于安全连锁规则设计了机器保护系统,实现了运行异常下的连锁保护。该控制系统应用于国内首套深地实验强流ECR离子源,运行稳定可靠,完全满足JUNA运行及物理实验的需求。
