在^(76)Ge同位素生产工艺中,电动调节阀是通过DCS(Distributed Control System)的PID模块来控制,从而实现级联管线内部压力的自动调节;但当工艺系统出现较大压力波动时,现有的电动调节阀控制方法,无法达到最优的控制效果,导致被控工艺...在^(76)Ge同位素生产工艺中,电动调节阀是通过DCS(Distributed Control System)的PID模块来控制,从而实现级联管线内部压力的自动调节;但当工艺系统出现较大压力波动时,现有的电动调节阀控制方法,无法达到最优的控制效果,导致被控工艺压力超出运行安全限值,对工艺系统的安全稳定运行产生了严重不良影响。本研究针对目前电动调节阀在压力异常情况下控制性能较弱问题,提出了对电动调节阀的DCS控制组态程序进行优化的控制方案。实际运行表明,优化后的控制程序避免了异常情况下工艺压力出现较大波动的现象,有力地保障了^(76)Ge同位素生产线的安全平稳运行。展开更多
以国内首个^(76)Ge同位素分离工程的离心级联检测控制为对象,通过DCS(Distributed Control System)控制系统硬件结构和组态编程,确保了主工艺关键设备——稳旋机的安全性,实现了实时查看现场各类工艺参数、远程开关电动阀、远程调节阀...以国内首个^(76)Ge同位素分离工程的离心级联检测控制为对象,通过DCS(Distributed Control System)控制系统硬件结构和组态编程,确保了主工艺关键设备——稳旋机的安全性,实现了实时查看现场各类工艺参数、远程开关电动阀、远程调节阀门开度及远程启停真空泵等功能,有力地保障了^(76)Ge同位素生产线的安全平稳运行。展开更多
We operated a p-type point contact high purity germanium(PPCGe)detector(CDEX-1B,1.008 kg)in the China Jinping Underground Laboratory(CJPL)for 500.3 days to search for neutrinoless double beta(0νββ)decay of ^(76)Ge....We operated a p-type point contact high purity germanium(PPCGe)detector(CDEX-1B,1.008 kg)in the China Jinping Underground Laboratory(CJPL)for 500.3 days to search for neutrinoless double beta(0νββ)decay of ^(76)Ge.A total of 504.3 kg⋅day effective exposure data was accumulated.The anti-coincidence and the multi/single-site event(MSE/SSE)discrimination methods were used to suppress the background in the energy region of interest(ROI,1989–2089 keV for this work)with a factor of 23.A background level of 0.33 counts/(keV⋅kg⋅yr)was realized.The lower limit on the half life of^(76)Ge 0νββdecay was constrained as T_(1/2)^(0ν)>1.0×10^(23)yr(90%C.L.),corresponding to the upper limits on the effective Majorana neutrino mass:<mββ><3.2–7.5 eV.展开更多
We report the first results on 76Ge neutrinoless double beta decay from stage one of the China dark-matter experiment （CDEX）. A p-type point-contact high-purity germanium detector with a mass of 994g has been instal...We report the first results on 76Ge neutrinoless double beta decay from stage one of the China dark-matter experiment （CDEX）. A p-type point-contact high-purity germanium detector with a mass of 994g has been installed to detect neutrinoless double beta decay events, as well as to directly detect dark matter particles. An exposure of 304kgd has been analyzed over a wide spectral band from 500keV to 3MeV. The average event rate obtained was about 0.012 counts per keV per kg per day over the 2.039MeV energy range. The half-life of76Ge neutrinoless double beta decay derived based on this result is 70v2〉6.4× 1022 yr （90%C.L.）. An upper limit on the effective Majorana-neutrino mass of 5.0eV has been achieved.展开更多
The properties of low-lying states in 76Ge, especially the characteristics of the mixed-symmetry states, have been investigated within the neutron-proton interacting boson model （IBM-2）. By considering the relative ...The properties of low-lying states in 76Ge, especially the characteristics of the mixed-symmetry states, have been investigated within the neutron-proton interacting boson model （IBM-2）. By considering the relative energy of d proton boson to be different from that of neutron boson, the low-lying positive parity levels and M1, E2 transition strengths have been calculated. The IBM-2 calculated results are in good agreement with the experimental data. Particularly, the mixed-symmetry states have been reproduced quite well. The calculation and systematic analysis demonstrated that the collective character of 76Ge lies closest to the SUπv^＊（3）, with some possible Oπv（6） dynamic symmetry in IBM-2 viewpoint.展开更多
文摘在^(76)Ge同位素生产工艺中,电动调节阀是通过DCS(Distributed Control System)的PID模块来控制,从而实现级联管线内部压力的自动调节;但当工艺系统出现较大压力波动时,现有的电动调节阀控制方法,无法达到最优的控制效果,导致被控工艺压力超出运行安全限值,对工艺系统的安全稳定运行产生了严重不良影响。本研究针对目前电动调节阀在压力异常情况下控制性能较弱问题,提出了对电动调节阀的DCS控制组态程序进行优化的控制方案。实际运行表明,优化后的控制程序避免了异常情况下工艺压力出现较大波动的现象,有力地保障了^(76)Ge同位素生产线的安全平稳运行。
文摘以国内首个^(76)Ge同位素分离工程的离心级联检测控制为对象,通过DCS(Distributed Control System)控制系统硬件结构和组态编程,确保了主工艺关键设备——稳旋机的安全性,实现了实时查看现场各类工艺参数、远程开关电动阀、远程调节阀门开度及远程启停真空泵等功能,有力地保障了^(76)Ge同位素生产线的安全平稳运行。
基金Supported by the National Key Research and Development Program of China(2017YFA0402201,2022YFA1604701,2022YFA1605000)the National Natural Science Foundation of China(12322511,12175112,12005111,11725522)。
文摘We operated a p-type point contact high purity germanium(PPCGe)detector(CDEX-1B,1.008 kg)in the China Jinping Underground Laboratory(CJPL)for 500.3 days to search for neutrinoless double beta(0νββ)decay of ^(76)Ge.A total of 504.3 kg⋅day effective exposure data was accumulated.The anti-coincidence and the multi/single-site event(MSE/SSE)discrimination methods were used to suppress the background in the energy region of interest(ROI,1989–2089 keV for this work)with a factor of 23.A background level of 0.33 counts/(keV⋅kg⋅yr)was realized.The lower limit on the half life of^(76)Ge 0νββdecay was constrained as T_(1/2)^(0ν)>1.0×10^(23)yr(90%C.L.),corresponding to the upper limits on the effective Majorana neutrino mass:<mββ><3.2–7.5 eV.
基金supported by the National Natural Science Foundation of China(Grant Nos.11275107,11475117,11475099,and 11675088)the National Key Basic Research Program of China(Grant No.2010CB833006)
文摘We report the first results on 76Ge neutrinoless double beta decay from stage one of the China dark-matter experiment （CDEX）. A p-type point-contact high-purity germanium detector with a mass of 994g has been installed to detect neutrinoless double beta decay events, as well as to directly detect dark matter particles. An exposure of 304kgd has been analyzed over a wide spectral band from 500keV to 3MeV. The average event rate obtained was about 0.012 counts per keV per kg per day over the 2.039MeV energy range. The half-life of76Ge neutrinoless double beta decay derived based on this result is 70v2〉6.4× 1022 yr （90%C.L.）. An upper limit on the effective Majorana-neutrino mass of 5.0eV has been achieved.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11475062, 11647306, and 11147148)
文摘The properties of low-lying states in 76Ge, especially the characteristics of the mixed-symmetry states, have been investigated within the neutron-proton interacting boson model （IBM-2）. By considering the relative energy of d proton boson to be different from that of neutron boson, the low-lying positive parity levels and M1, E2 transition strengths have been calculated. The IBM-2 calculated results are in good agreement with the experimental data. Particularly, the mixed-symmetry states have been reproduced quite well. The calculation and systematic analysis demonstrated that the collective character of 76Ge lies closest to the SUπv^＊（3）, with some possible Oπv（6） dynamic symmetry in IBM-2 viewpoint.
