β-delayed neutron decay of 21N

The β-delayed neutron and γ spectra of neutron-rich nucleus ²¹N using β-γ and β-n coincidence measurements were presented in this paper. Thirteen new neutron groups ranging from 0.28 MeV to 4.98 MeV and with a total branching ratio 88.7±4.2% were observed. One γ transition among the excited states of ²¹O, and four γ transitions among the excited states of ²⁰O were identified in the β decay chain of ²¹N. The ungated half-life of 83.8±2.1 ms was also determined for ²¹N.     

CsI(Tl)晶体探测器APD读出的温度效应

对中国科学院近代物理研究所自行生长的铊激活碘化铯闪烁晶体CsI(Tl)光输出及Hamamtsu公司生产的S8664-1010型雪崩光二极管(APD)增益对温度的依赖关系做了系统研究. 结果表明, CsI(Tl)晶体光产额在室温范围内随着温度的增加而增加, 在－2℃—8℃温度范围内的平均温度系数为0.67%/℃, 在8℃—25℃温度范围内的平均温度系数为0.33%/℃. 而对所使用的APD, 其增益在室温范围内的温度系数为－3.68%℃(工作电压400V). APD结合CsI(Tl)晶体在室温下对¹³⁷Cs的662keV γ射线的能量分辨可达5.1%.     

Characteristics of a 4-fold segmented clover detectore

Four high-purity germanium 4-fold segmented Clover detectors have been     

基于Pluto事件产生器对兰州强子物理谱仪上主要反应道的模拟研究

为了在 GeV 能区开展核子核子相互作用中强子的产生和衰变的实验研究, 将在 HIRFL CSR 主环上建造一台兰州强子物理谱仪（HPLUS）。 首先结合 HPLUS 的初步构型阐明了针对不同极角区域的粒子鉴别方法, 接着介绍了在蒙特卡罗模拟中使用的 Pluto 事件产生器, 并针对 HPLUS上主要的反应道模拟研究了: Pluto 产生的质子质子弹性散射的角分布和实验数据的符合程度; 在产生 K 介子的反应道中, HPLUS 前角区对 K 介子的接收度; 强子衰变产生光子的最大能量和两个光子的最小夹角随极角区域的变化情况; 不同的重建方法对核子激发态质量谱形状的影响。以上研究说明了 Pluto 事件产生器可以满足 HPLUS 模拟的需要。 Hadron Physics Lanzhou Spectrometer (HPLUS) is designed for the study of hadron production and decay from nucleon nucleon interaction in the GeV region. The current formation of HPLUS and the particle identification methodsfor three polar angle regions are discussed. The Pluto event generator is applied to simulate the primary reactions on HPLUS, concerning four issues as followed: the agreement on pp elastic scattering angular distribution between Pluto samples and experimental data; the acceptance of charged K mesons in the strangeness production channels for the forward region of HPLUS; thedependence of the maximum energy of photons and the minimum vertexangle of two photons on the polar angle; the influence on the mass spectrum of excited states of nucleon with large resonant width from different reconstruction methods. It is proved that the Pluto event generator satisfies the requirements of Monte Carlo simulation for HPLUS.     

Characteristics of a 4-fold segmented clover detectore

Four high-purity germanium 4-fold segmented Clover detectors have been applied in the experiment of neutron-rich nucleus 21N. The performance of those four Clovers have been tested with radioactive sources and in-beam experiments, and the main results including energy resolution, peak-to-total ratios, the variation of the hit pattern distribution in different crystals of one Clover detector with the energy of γ ray, and absolute full energy peak detection effciency curve, were presented.