兰州大学机构库 >物理科学与技术学院
裂变碎片飞行时间测量技术的研究
Alternative TitleA Study on Time-of-Flight Technique for Detection of Fission Fragments
孟庆华
Thesis Advisor陈熙萌 ; 韩洪银
2004-05-12
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword252Cf(sf 裂变碎片 MCP+SBD飞行时间技术 探测效率 时间分辨
Abstract裂变碎片的质量鉴别是原子核自发裂变研究的主要方面,本硕士论文的研究工作在于:建立用于测量裂变碎片质量的 “微通道板(MCP)+ 半导体探测器(SBD)”飞行时间探测系统,并研究其性能。 在粒子的出射方向安装碳膜(80 g/cm2),当粒子穿过碳膜时所产生的次级电子经加速,然后被偏转栅偏转90°后入射到MCP,MCP的收集极给出事件发生的时间标志信号,作为飞行时间系统(TOF)的终止信号。穿过碳膜的裂变碎片飞行一段距离后,被SBD探测,经电荷灵敏前置放大器(ORTEC 142B)给出反映粒子动能的能量信号和反映其质量的TOF的起始信号。由KODAQ数据获取系统完成能量与飞行时间的两参量关联测量。 经调试和检测,该系统对241Am的 粒子的探测效率约为39%,对252Cf(sf)裂变碎片的探测效率约为98%。在EK= 78MeV条件下,探测系统对252Cf(sf)重裂变碎片(138amu-148amu)得到的时间分辨为224.1±6.1ps; 在EK = 102MeV条件下,对252Cf(sf)轻裂变碎片(101amu-111amu)得到的时间分辨为154.5±5.8ps。 本工作利用241Am的 粒子对系统进行了时间刻度,用252Cf(sf)自转移源测量了裂变碎片产物质量谱。
Other Abstractorder to determine the mass of fragments in fission reaction, it is essential to develop a TOF( time-of-flight ) system. The purpose of this work is to set up a TOF detection system that include a micro-channel plate (MCP) and a semiconductor surface barrier detector (SBD), and study it. A carbon foil of 80 g/cm2 was mounted in the direction of the particle trajectories. The secondary electrons produced by particles passing through the carbon foil were accelerated, and then deflected by 90°onto MCP using an electrostatic mirror formed by two parallel grids. The stop signal of the TAC(time-to-amplitude converter ) was derived from the collecting anode of MCP. After flight a suitable distance, the projectiles impact on SBD. The charge-sensitive preamplifier (ORTEC 142B) associated with SBD provided the E signal related to the energy of particle and T signal as the start signal of the TAC related to the mass of particle. A two-parameter correlation measurement was completed in KODAQ data acquisition system. The TOF system shows a detection efficiency of 39% for particles released from 241Am and 98% for fragments in the spontaneous fission of 252Cf. The time resolutions are 224.1±6.1ps for the heavy fragments(EK=78MeV, AH=138amu-148amu) and 154.5±5.8ps for the light fragments(EK =102MeV, AL=101amu-111amu). Time calibration was completed using particles of 241Am. Mass spectra of the fission products were measured using 252Cf(sf) self-transfer source. "
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229592
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
孟庆华. 裂变碎片飞行时间测量技术的研究[D]. 兰州. 兰州大学,2004.
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