闪烁体探测器中光的衰减通式(英文)

闪烁体探测器被广泛应用于当今粒子物理与原子核物理实验中。研究闪烁探测器的光衰减规律（LASD）对时间和能量的准确测量都十分重要，这一点对条形闪烁探测器尤为如此。本文以圆柱闪烁探测器为例，对各向同性的闪烁光进行立体角积分，进而研究不同立体角下光程差异对结果的影响。在数值计算的基础上，导出了描述LASD的通用公式。在一定条件下，公式可以约化为双指数衰减形式。对于DAMPE上PSD的实验数据，该公式能使闪烁体远端的拟合偏差从大约10%降低至2%以下。同时，模型也能够很好地描述Kaiser实验、Gierlik实验和Platino实验的实验数据。Scintillator detectors are widely used in modern nuclear and particle physics experiments. Studying the light attenuation of scintillator detector (LASD) is vitally important for extracting proper measurements of energy and time. In this paper, we integrate the isotropic fluorescence over solid angle to study the influence on overall light-intensity from varying optical path at different angle. Based on numerical results, a universal formula for describing LASD is derived. Under certain condition, our formula can be written as a form of widely-used double-exponential function. The universal formula describes the experimental data of PSD at DAMPE, reducing the maximum deviation at far-side of the scintillator from~10% to less than 2%. Moreover, our model also deciphers Kaiser's experiment, Gierlik's experiment and Platino's experiment successfully.     

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.     

小型宇宙射线探测仪的模拟和测量

介绍了一款小型宇宙射线探测仪。该仪器具有宇宙射线科普演示功能,主要用于实时测量μ子射线并显示计数,以及长时间尺度下（年）稳定地对不同角度的次级宇宙线通量进行监控记录。简要地展示了探测器的硬件构造和探测效率的模拟计算。探测仪单个探测器的探测效率为93.1%,两个探测器符合测量的探测效率为86.6%。根据探测器的计数率以及模拟计算的探测效率,估计了次级宇宙射线垂直地面方向的通量,为J=29±3 m-2 sr-1 s-1。另外,利用该宇宙射线探测仪,测量了兰州市区的次级宇宙射线的天顶角分布。其结果很好地满足I（θ）=IH+I₀ cosα θ经验公式,其中的角度依赖参数α=2.42±0.52。A small cosmic ray device is introduced in this paper.It has the demonstration function for popularization of science,and can be used mainly to display the μ counts in a real-time measurement,and to monitor the secondary cosmic ray flux at different angles in a very long time scale (years).We briefly show the hardware of the device and the detecting efficiency calculation by simulation.The detecting efficiency for one detector of the device is 93.1%,and the detecting efficiency is 86.6% for the coincidence measurement of two detectors.Based on the count rate by the detector and the simulated efficiency,the secondary cosmic ray flux perpendicular to the ground surface is measured,which is J=29±3 m-2sr-1 s-1.Moreover,with an application of the device,we measured the angular distribution of the secondary cosmic ray rate in Lanzhou City.The resulting angular distribution agrees well with the empirical formula as I(θ)=IH+I₀ cosα θ,in which the parameter for the angle-dependence is α=2.42±0.53.     

Quasi-Elastic Scattering of 16C from 12C at 47.5 MeV/Nucleon

Differential cross sections for the quasi-elastic scattering of^16 C at 47.5 MeV/nucleon from ^12 C target are measured.Coupled-channels calculations are carried out and the optical potential parameters are obtained by fitting the experimental angular distribution.     

Fast simulation of the forward tracking detector of HPLUS

The necessity of installing a forward tracking detector stack is discussed for the Hadron Physics LanzhoU Spectrometer(HPLUS). A local tracker is developed to solve the multi-track finding problem. The track candidates are searched iteratively via Hough Transform. The fake tracks are removed by a least square fitting process. With this tracker we have studied the feasibility of     

双过渡层阴极对流延法制备的阳极支撑直接碳固体氧化物燃料电池性能的改善作用

采用流延法制备了阳极支撑的固体氧化物燃料电池(SOFC),电解质材料为钇稳定化氧化锆(YSZ),阳极为镍和YSZ构成的金属陶瓷(Ni-YSZ),阴极为LSCF-GDC/LSCF复合材料,同时在阴极与电解质之间制备了YSZ-GDC/GDC双过渡层。分别采用含3%的加湿H_2和活性炭为燃料,对此电池的输出性能及阻抗谱进行测试。采用加湿H_2测试的结果表明:在800℃下,采用双过渡层电池的开路电压达到1 V,最大功率密度为680 mW·cm~(-2),比未改良电池的最大功率密度(372 mW·cm~(-2))提高了83%。直接采用固体碳为燃料时,具有双过渡层阴极的电池在850℃时的开路电压达到0.95 V,最大输出功率密度达429 mW·cm~(-2),几乎比无过渡层阴极的电池(225 mW·cm~(-2))高出1倍,特别是双过渡层阴极还使直接使用碳燃料的SOFC(DC-SOFC)的燃料利用率提高了33%。     

Characteristics of a 4-fold segmented clover detectore

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

火花放电原子发射光谱法测定钛及钛合金中主要元素

采用火花放电原子发射光谱法测定了钛及钛合金中碳、铁、铝和钒的含量。通过对钛合金样品的表面处理方式、氩气流量和压力、类型标准化等参数的摸索,确立了一套系统的分析方法。结果表明,4种元素测定的相对标准偏差在0.40%~6.8%,测定结果和化学湿法分析结果相比基本一致,比较适合批量检测。     

超氚核寿命之谜及其展望(英文)

近期，基于重离子碰撞的实验组（HypHI，STAR）发表了超氚核（hypertriton）的寿命测量结果。其结果显示，超氚核的寿命比Λ超子短~30%。由于超氚核是一个非常松散的结合态，超氚核的寿命不应远离Λ超子的寿命太多。这一难以解释的现象被称为超氚核的短寿命之谜。为了从不同的实验方法检验超氚核的寿命，我们提出利用J-PARC的K-束流，通过K-+3He → _Λ3H+π0的反应道来测量超氚核寿命的实验。本文将回顾测量超氚核寿命的主要结果，并介绍目前实验方面的最新进展。本合作组提出的原创性实验方案不会受到径迹重建效率的影响，能够为验证超氚核的寿命提供重要的实验数据。