高气压屏栅电离室的调试和58Ni(n,p)反应双微分截面的试测

介绍了高气压屏栅电离室的结构和调试,并对＾５８Ｎｉ（ｎ,ｐ）试测结果进行了分析,结果证明此电离和测量方法对（ｎ,ｐ）反应的测量是适用的。目前正用此电离室进行测量（ｎ,ｐ）反应堆面的实验。     

一个屏栅电离室计数器望远镜

本文描述一个以屏栅电离室作△E探测器,以Au-Si面垒探测器测定核粒子剩余能量E_R的△E-E计数器望远镜,如图1所示。作为阴极而处于地电位的壳体是由黄铜加工而成的。入射窗架固定在前盖板上,它同时又充当入射粒子的准直孔(φ4 mm×40 mm)。     

超大面积屏栅电离室的研制

核设施退役过程中,需对超过1 000 cm²以上的大面积超铀核素平面板放射性进行准确定量,常用无损测量方法有效测量面积均较小,且探测限较高,不能满足快速分析大面积低活度样品的需求。屏栅电离室是一种用于低水平α放射性能谱测量的仪器,可满足以上分析需求,但受制于电极加工工艺,可测样品一般小于500 cm²。为解决以上问题,研制了灵敏面积接近2 000 cm²的超大面积屏栅电离室,通过对工作气压和电压的调试优化,该电离室对²⁴¹Am电沉积源的能量分辨率为1.8%,最小可探测活度为10^-2 Bq,对直径≤460 mm的平面样品2π角探测效率为97.7%。     

大面积α屏栅电离室的研制

研制了一台大面积低本底α屏栅电离室,其阴极表面积为1500cm~2,收集极对地电容约20pF,充以1.8大气压的 P_(10)气体(90%氩+10%甲烷)。分析了几种主要因素对能量分辨率的贡献,在源自吸收贡献为30keV 情况下,对~(210)Poα源的能量分辨率约为41keV。在4—6MeV 能区内装置的本底为6.1cph,在5MeV 处50keV 谱宽内的本底为0.1cph。采用新试制的氧化锆除氧炉循环净化负电性气体,以保证长时间稳定工作。对~(210)Po 电沉积小源测得的分辨率约为35—45keV;对于厚度为40μg/cm~2的1500 cm~2大源测得的分辨率平均为69keV,和估算值相符。最低可测放射性强度为10~(-14)—10~(-15)Ci。     

α屏栅电离室谱仪系统的研制

在α放射性活度测量中,屏栅电离室是一种常用装置,在众多领域得到广泛应用。该装置适用于各种环境样品,如土壤、水、空气、生物样品、食品、建材、地质及考古样品的测量,后处理中的α发射体、禁产核查及物料衡算样品中微量α放射性的测量,以及核设施周围环境介质中人工放射性核     

大面积屏栅电离室α谱仪的研制

大面积屏栅电离室α谱仪的研制@汪建清@佟伯亭@姚艳玲@王国军     

α屏栅电离室谱仪系统的研制

介绍用于α放射性活度测量的平行板屏栅电离室谱仪系统.设计了一套带独立真空系统的屏栅电离室.该谱仪系统由三部分组成,电离室主体、充气系统及电子学系统.能量分辨率对于239Pu源可达25keV,在4～6MeV能区本底计数率为4h-1,探测效率接近50%.该谱仪系统可以测量核素的α射线能量,分析出它们的能谱结构,进而鉴定出各个α能谱所相应的核素及其相对含量和绝对含量.     

3 α屏栅电离室谱仪系统的研制

在α放射性活度测量中，屏栅电离室是一种常用装置，在众多领域得到广泛应用。该装置适用于各种环境样品，如土壤、水、空气、生物样品、食品、建材、地质及考古样品的测量，后处理中的α发射体、禁产核查及物料衡算样品中微量α放射性的测量，以及核设施周围环境介质中人工放射性核素的监测。     

高气压电离室的设计研究

本文设计了一种高气压氩气电离室.在设计中,以MCNP和EGSnrc程序的计算结果作为指导选取高气压电离室工作气体及壁材.通过分析电离室的壁厚、直径和工作气体压力等因素对电离室性能的影响,找出合适的参数.实验标定的结果表明:该电离室的能量响应性能良好.     

微量α测量的屏栅电离室谱仪的研制

为了测量微量α放射性活度,研究了平行板α屏栅电离室谱仪系统。设计了一套带独立真空系统的屏栅电离室。该谱仪系统将电离室主体、充气系统及电子学系统三部分集成为一体,可缩小体积,节省放置空间,使操作智能化。电离室测试结果显示,239 Pu源能量分辨率可达26keV,在4~6 MeV能区本底计数率为10h~(-1),24h系统漂移不大于0.5%。结果表明,该谱仪系统可用于测量核素的α射线能量,分析能谱结构,鉴定核素。     

Cross section measurements of the 23Na(n, 2n)22Na, 58Ni(n, 2n)57Ni and 115In(n,n′)115mIn reactions

Cross sections for two high energy threshold reactions ²³Na(n, 2n)²²Na and ⁵⁸Ni(n, 2n)⁵⁷Ni were measured by the activation method in the neutron energy range from 14 to 18 MeV. Inelastic scattering cross section for ¹¹⁵In was measured in the threshold region, i.e. from 0.5 to 1.3 MeV. The results of measurements are compared with scarce and divergent earlier data.     

Measured activation cross sections below 10 MeV for the 51V(n,p)51Ti and 51V(n, α)48Sc reactions

The activation method is used to measure cross sections for the ⁵¹V(n, p)⁵¹Ti reaction from E_n = 2.856 to 9.267 MeV and for the ⁵¹V(n, α)⁴⁸Sc reaction from 5.515 to 9.567 MeV. Both measurements utilize ENDF/B-V evaluated neutron-induced fission cross sections of ²³⁸U as a standard. The experimental results from this work are compared with corresponding ENDF/B-V evaluated cross sections for V and substantial differences are evident. The most significant difference is a tendency for the measured values to exceed evaluated ones by as much as 50% in the vicinity of 8 MeV.     

63Ni辐射伏特同位素电池原型的研制

利用理论研究获得的换能单元参数制备了单晶硅基换能单元,确定了⁶³Ni的加载工艺和原型电池的封装材料配方与技术,通过加速热老化和温度交变考核了原型电池的性能。结果表明：所制备的⁶³Ni辐射伏特效应微型同位素原型电池的短路电流I_sc、开路电压V_oc、最大输出功率P_max和衰变能-电能转换效率η分别为5.97 nA、88.0 mV、0.255 nW和0.561%;原理样机稳定输出超过220 d。     

Measurement of 134Xe(n,2n)133m,gXe reaction cross sections in 14-MeV region with detailed uncertainty quantification

A lead-shielded HPGe detector and offline γ-ray spectra of the residual product were used to measure the cross section(CS)and ratios of isomeric CS(σm/σg) in ¹³⁴Xe(n,2n)^133m,gXe reactions at different energies(13.5 MeV, 13.8 MeV, 14.1 MeV,14.4 MeV, 14.8 MeV) relative to the ⁹³Nb(n,2n)^92m Nb reaction CS. The target was high-purity natural Xe gas under high pressure. The T(d,n)⁴He reaction produces neutrons. TALYS code(version 1.95) for nuclea...     

Recoil range of 2.7 MeV tritons produced by the 6Li(n, α) 3H reaction in Li2O single crystals

The tritium release from Li₂O single crystals due to a recoil process during neutron irradiation was investigated. The linear relationship between the number of tritium atoms ejected from Li₂O and the ⁶Li(n, α) ³H reaction density was observed up to about 1 × 10²⁴ reactions/m³ and the linearity was deviated above this reaction density. From this linear relationship, the recoil range of 2.7 MeV tritons in Li₂O single crystals was determined and discussed in terms of the calculated value.     

用屏栅电离室测量~6Li(n,t)~4He反应微分截面

用屏栅电离室对 3.6 7MeV与 4 .4 2MeV中子6Li(n ,t) 4He反应微分截面进行了测量。利用氘气体靶通过D(d ,n) 3 He反应产生中子 ,用BF3 和液闪探测器 (NE2 13)进行相对中子通量监测 ,绝对中子通量用2 3 8U(n ,f)与H(n ,p)反应来刻度。测量结果表明 ,氚的质心系微分截面在中子能量为 3.6 7MeV时很接近 90°对称 ,而到 4 .4 2MeV时则明显前倾     

Multiple-models predictions for drip line nuclides in projectile fragmentation of 40,48Ca,58,64Ni,and 78,86Kr at 140 MeV/u

Modern rare isotope beam (RIB) factories will significantly enhance the production of extremely rare isotopes (ERI) at or near drip lines.As one of the most important methods employed in RIB factories,the production of ERIs in projectile fragmentation reactions should be theoretically improved to provide better guidance for experimental research.The cross-sections of ERIs produced in 140 MeV/u ^78;86Kr/^58;64Ni/^40;48Ca+ ⁹Be projectile fragmentation react...     

Prediction of (n,3He) cross-sections around 14 MeV

A comprehensive review of the neutron-induced cross-sections for (n,³He) reactions has been made for the interval of 14⩽Z⩽84 around 14 MeV neutron energy. For practical purposes, an empirical expression has been found by using the experimental (n,³ He) cross section values as a function of (N-Z) and (E_n-E_th) where (N-Z) is the neutron excess of the target nucleus, E_n and E_th are the incident neutron energy and the (n,³He) threshold energy, respectively. The derived empirical relation gives a good fit with the experimental values     

The (p, n) reaction in lithium and the ground state of Be6

Using a time-of-flight method the neutron spectra in the Li⁶ + + p and Li⁷ + p reactions have been investigated at a proton energy of 9 Mev. Neutron groups have been found in the (p, n) reaction corresponding to the ground state in Be⁶ and the three lowest states of Be⁷ as well as a continuous neutron spectrum at lower energy, due to more complicated reactions. The observation of the neutron group for the Li⁶(p, n)Be⁶ reaction is the first experimental indication of the existence of the Be⁶ nucleus. The energy of the Li⁶(p, n)Be⁶ reaction is 5.2 Mev, the width of the ground state in Be⁶ is T < 0.3 Mev. The differential cross sections for neutron formation have been measured at 0, 15, 30, 60 and 120 °.The authors wish to thank their colleagues at the Cyclotron Laboratory, who made the present work possible; we are also indebted to A. I. Baz who participated in a discussion of the results.