CsI(Tl)探测器对带电粒子能量响应的入射位置依赖关系

在放射性核束物理的实验研究中,通常采用CsI(Tl)探测器对反应产物中的带电粒子进行总能量测量.使用GEANT4软件对CsI(Tl)闪烁体探测器能量响应通进行了蒙特卡罗模拟,在考虑了晶体外表面包覆材料反射率、耦合光敏二极管面积、射程等影响因素后,重点研究了CsI(Tl)闪烁体探测器对带电粒子能量响应的入射位置依赖关系....     

寻找△—△双重子的实验设计

通过ＭｏｎｔｅＣａｒｌｏ模拟，完成了ＴＲＩＵＭＦ实验室的寻找△－△双重子实验的设计方案。     

一种高精度大范围时间测量电路的实现

在实验核物理中,经常要用到时间测量技术。时间测量有多种方式,其中用电子学方法实现时间的数字化(TDC)技术是一种常用的技术。根据对时间测量不同的需要,对其测量范围和测量的精度有不同的要求,介绍一种大测量范围高精度时间测量电路的实现,其实现的原理和设计方法,并给出了测量的结果。     

Experimental Study of Two-Neutron Correlation in ~8He~+

A neutron detector array was used in a breakup reaction experiment at RIKEN with an 82.5 MeV/u 8He beam impinging on the CH2 and C targets. The array was calibrated using the cosmic ray, the γ ray from the 6 He+Pb reaction and the mono-energetic neutrons from the 7Li(p, n)7Be(g.s.+0.43 MeV) reaction. The position resolution, timing resolution and neutron detection efficiency were obtained accordingly. Cross-talk rejection conditions were developed based on analysis of the data taken from the 7Li(p, n) 7Be(g.s.+0.43 MeV) test experiment, and finally a preliminary two-neutron correlation function for the 8 He breakup reaction was investigated.     

Some Key Problems Related to Radioactive Ion Beam Physics

The latest progress made in the field of radioactive ion beam physics is outlined and the key problems still under investigation are indicated. The focal points are the limit of nuclear existence, shell evolution and new magic numbers, halo and cluster structures, new excitation modes, and strong coupling between reaction channels. This field is still at a starting phase and much more new outcomes are foreseen.     

Recoiled Proton Tagged Knockout Reaction for ~8He

An experiment for knockout reaction induced by 8He beam at 82.5 MeV/nucleon on CH2 and C targets was carried out. The 6He and 4He core fragments at forward angles and the recoiled protons at large angles were detected coincidently. From this exclusive measurement the valence nucleon knockout mechanism and the core knockout mechanism are separated, which can be applied to the exclusive spectroscopic study on the structure of exotic nuclei.     

低压多丝正比室的位置分辨研究

低压多丝正比室为放射性束核反应的靶前粒子提供位置和时间信号。本工作用²⁴¹Amα源研究电压、工作气体压强等因素对低压多丝正比室位置分辨的影响。实验结果表明：在不同的气体压强条件下，低压多丝正比室的位置分辨均可达到1mm，但考虑到时间、效率等因素，实验中需尽可能提高气压。     

加速器驱动洁净核能系统散裂靶辐射损伤研究——Ⅱ．气体产生

对加速器驱动洁净核能系统散裂中子靶和靶窗材料分别在中子和质子入射情况下氦气产生截面、氦气产生率以及氦气产生率与原子位移率的比值进行了研究。利用SHIELD程序模拟计算的结果与实验数据及其他程序的计算值符合很好。     

北京ISOL项目进展

北京ISOL（北京在线分离丰中子束流装置，亦简称BISOL）是由中国原子能科学研究院和北京大学联合提出的一台大科学装置。项目建设包括反应堆与加速器驱动放射性核束离子源、强流氘离子加速器、高功率靶站与核能材料辐照装置、放射性核束后加速器、放射性核束实验站等。装置建设方案已初步确定，装置建成后可产生较国内外现有装置强度高1~2个量级的极端丰中子束流，可开展学科基础前沿放射性核束物理的创新研究，同时兼顾先进核能系统开发和多种核技术应用的需求。     

Study of Isotopic Distribution of the Projectile-like Fragments Produced in the 17,18N + 197Au Reactions at 33 MeV/u

The experimental data of the isotopic distribution for projectile-like fragments are presented for the 17,18N + 197Au reaction at 33MeV/u. The width of the isotopic distributions for 18N projectile is significantly broader than that for 17N projectile, and the average N/Z ratio of the former shifts to higher neutron number side. As long as the realistic nucleon density distribution is used, the isotopic distribution for fragments is reproduced by the simple abrasion-ablation model calculation, which thus provides an independent way to determine the surface distribution of the nuclear matter density for neutron-rich nuclei.