用固体气泡损伤探测器成功地记录质子

用自行研制的T-15型固体气泡损伤探测器,在日本和光市理化学研究所（RIKEN）回旋加速器上用210MeV质子对其记录质子的性能进行了研究。实验证明:T-15型固体气泡损伤探测器能直接记录质子径迹。由于质子的可记录射程很短,质子径迹只由少数气泡组成。用固体气泡损伤探测器记录质子径迹的成功将扩展固体气泡损伤探测器的应用领域,对已开展     

固体气泡损伤探测器探测高能重离子的研究

用高能重离子Ar和C进行的实验表明：（1）高能重离子可以在固体气泡损伤探测器中产生径迹,重离子径迹呈直线形,由一连串微小气泡组成;（2）固体气泡损伤探测器探测重离子具有阈特性,阈的实质近似为临界能量损失率（dE／dX）C,这一阈特性与蚀刻径迹探测器类似。固体气泡损伤探测器的阈值为（dE／dX）c=2220MeV／g·cm2,可用于重离子物理、宇宙射线和宇宙暗物质探测以及癌症治疗模拟等领域。     

基于CR-39固体探测器的粒子识别

为了掌握利用CR-39固体核径迹探测器识别α粒子和质子的方法,应用粒子与物质相互作用理论和径迹蚀刻动力学经验模型,模拟了α粒子和质子在CR-39固体核径迹探测器上的径迹形貌,计算出了3~8 MeV的α粒子和1~9 MeV的质子最佳蚀刻条件。根据对应的最佳蚀刻条件,计算获得的α粒子和质子的径迹直径、灰度值、径迹深度,并据此对相同能量的α粒子和质子、不同能量的α粒子、不同能量的质子进行识别。同时,采用CR-39固体探测器对α粒子(5.48 MeV)和质子(3 MeV)进行了实验测量,在模拟计算所获得的最佳蚀刻条件下,实验测读了α粒子径迹。实验测量得到的α粒子径迹直径与模拟值相差0.36%~9.70%。实验测量的最佳蚀刻时间和模拟的最佳蚀刻时间相差5.60%,这些结果验证了模拟方法的可行性。     

用高能重离子刻度固体气泡损伤探测器的阈值

用自行研制的5种固体气泡损伤探测器在日本国立辐射科学研究所高能重离子加速器HIMAC上用150MeV/u4He、490MeV/u28Si和500MeV/u56Fe对其进行了阈值刻度,得到它的阈值分别为:82.4（T-15型）、1536±232（T-34型）、1628±4（T-12型）、2335±332（T-24型）和 6 060±2 065（T-14型）MeV·g-1·cm2。它们的阈值在几十至几千MeV·g-1·cm2范围内分立排开,这一范围相当于常温情况下固体气泡损伤探测器通常能达到的最高灵敏度和最低灵敏度范围。由这些阈值可推算用固体气泡损伤探测器分辨重离子的分辨参数和推算各种     

CR-39探测器对α粒子入射角度和能量响应的实验研究

为掌握固体径迹探测器CR-39对α粒子的入射角度和能量响应特性,通过建立1个可调节α粒子的入射角度和入射能量的241Am源照射系统,进行了不同入射角度和入射能量的α粒子照射CR-39探测器的实验研究,比较了不同照射条件下的径迹密度.实验结果表明,CR-39对α粒子的能量响应下限约为0.5 MeV,对入射角度响应的上限约为70°.本研究结果可为优化设计测氡的扩散杯(瓶)、提高其对氡的探测效率等提供科学的指导依据.     

气泡中子探测器用于个人剂量监测

气泡中子探测器是可重复使用、积分型、无源剂量计。它的体积小,可对中子辐射进行直接、可视的测量。为了将气泡中子探测器用在个人剂量监测中,先验证气泡中子探测器对从0．2～15MeV能量的中子具有平直的能量响应。然后用5．10和1．3MeV的中子考察了气泡中子探测器的线性及其稳定性。     

固体气泡探测器-固体核径迹探测器的新类别

利用高能重离子p、He、C、Si、Ar、Fe、Kr和Xe对固体气泡探测器的性质进行了研究。结果表明,固体气泡探测器具有许多与固体核径迹探洲器相似的性质,且具有显影主动性、实时记录性、体径迹显示能力等多方面普通固体核径迹探测器所不具有的性能。可以得出结论：固体气泡探测器是固体核径迹探测器的一种新类别。     

PET核孔膜蚀刻速率影响因素的研究

核孔膜是通过重离子照射薄膜后进行化学蚀刻所得到的高性能过滤材料,蚀刻速率是影响高质量核孔膜制备的重要因素。本文探讨了不同蚀刻液浓度、温度以及重离子辐照能量对蚀刻速率的影响。利用140 MeV的32S离子在室温和真空条件下对4层堆叠的PET(polyethylene terephthalate)薄膜进行了辐照。在对辐照样品进行化学蚀刻期间采用电导法确定了径迹蚀刻速率Vt。结果表明:蚀刻速率与蚀刻温度呈指数相关,随蚀刻液浓度增加而线性增大;径迹蚀刻速率随能量损失率(离子能损)增大。研究确定,在入射32S能量为1.6 MeV·u-1时,NaOH浓度为1mol·L-1、蚀刻温度为85°C时最有利于形成圆柱形微孔。     

固体核径迹探测器的最新进展

本文介绍固体核径迹探测器近几年来的主要进展,如发现α反应径迹、合成CR-39-SO_2、气泡损伤探测法,以及在各领域中应用的新进展。     

空间带电粒子谱仪性能测试及能量刻度

采用金硅面垒探测器及CsI(Tl)探测器设计制作了一套△E-E型探测空间粒子的望远镜系统,利用α粒子、质子、氧离子、铁离子4种粒子对该望远镜系统和电子学系统进行性能测试和能量刻度。电子学的增益系统分为三挡,分别为1.0、1/3和1/12.75。实验结果表明:对于α粒子,采用1/3挡,在△E_1和△E_2探测器中每道能量分别是H_1=0.107 MeV和H_2=0.123 MeV。对质子能量的刻度,采用1挡,每道能量H值为0.016 7 MeV,这个H值几乎不随能量变化,在CsI探测器中,每道能量H为1.047 MeV。对氧离子的能量刻度采用1/12.75的挡别,刻度出每道能量是1.11 MeV。在探测器中,沉积能量高于50 MeV,电子学系统进入饱和状态。对铁离子的标定结果与氧离子的结果相同。     

Measurements of induced activity in concrete by secondary particles at forward direction produced by intermediate energy heavy ions on an Fe target

Spallation and neutron capture reaction rate distributions were measured using activation detectors inside a 90-cm thick ordinary concrete pile exposed to a field of secondary particles escaping a thick (stopping length) iron target bombarded with various intermediate energy ions, 230 MeV/u He, 400 MeV/u C, and 800 MeV/u Si. Activation detectors of aluminum, bismuth, gold, and gold covered with cadmium were inserted at various depths in the concrete pile. In addition, the distributions of activation reaction rate were simulated by FLUKA and PHITS Monte-Carlo codes. Generally, comparison of measured and calculated reaction rates show agreement within a factor of two. The experimental data will be useful for benchmarking Monte-Carlo radiation transport simulation code capabilities in estimating radioactivity induced in accelerator radiation shielding.     

A ctivation measurement of neutron distribution in intermediate energy heavy ion target area

The distribution of neutrons produced by the reaction of 50MeV/u ^12C-ion on a thick Cu target are studied.The neutrons are measured with threshold activation detectors.Al.F,C,Al and In activation samples were used to measure neutrons with energy greater than 7,11,20,50MeV and thermal neutrons,respectively,The fluence rate,energy and angular distributions of neutrons,total neutron yield of 12C-ion and the emission rate in the forward direction of neutrons over 11 and 20MeV were obtained.     

Irradiation by swift heavy ions: Influence of the non-equilibrium projectile charge state for near surface experiments

When dealing with surface and/or thin film modifications of materials under irradiation by swift heavy ions, special attention should be given to the choice the incident projectile charge state delivered by the accelerator. This charge state should be of the order of the effective charge defined in the electronic energy loss theory. Under some hypothesis, this effective charge is assumed to be equivalent to the mean charge state deduced from measurements of ion charge state distribution. To reach such a charge state, it is necessary to introduce before the irradiated sample a thin stripper foil of carbon, the thickness of which is in between 5 and 1500 μg/cm² for beam energies ranging between 1 and 44 MeV/u, respectively.     

Neutron dose equivalent rate for heavy ion bombardment

The fluence rate distribution of neutrons in the reactionsof 50MeV/u ^18O-ion on thick Be,Cu and Au targets have been measured with an activation method of threshold detectors andthe neutron dose equivalent rate distributions at 1m from the tqrgets in intermediate energy heavy ion target area are obtained by using the conversion factors from neutron fluence rate to neutron doseequivalent rate.     

高能氩离子辐照聚酰亚胺时的能量沉积效应对光学吸收及电性能的影响

用２２．５ＭｅＶ／ｕ的高能氩离子辐照层聚酰亚胺薄膜，对辐照样品的志电性测量及紫外可见光吸收分析表明，随单位体积中能量沉积的增加，薄膜的导电性增强，光吸收度增大，且光吸收边缘由近ＵＶ区向可见区移动。     

Simulation study of the dose and energy responses of FNTD personal neutron dosimetry

The objective of this work was to use the Geant4 toolkit to perform simulation studies on the personal dose response of fluorescent nuclear track detectors(FNTDs).The entire structure of the FNTD response can be designed,and the detector's energy and dose responses can be optimized in a broad energy range(0.01 eV-20 MeV). In general, the detectors used ~6LiF and CH_2 converters that have high energy and high dose response at neutron energies lower than 10 eV and greater than 1 MeV, respectively. The method of least squares was used to optimize the dose response of H*(10) and the energy response corresponding to Rtotal. The values of the optimized response of H*(10) lie between 0.8 and 1.4, corresponding to the energy ranges 0.01 eV-70 keV and 4-14 MeV, respectively. This occupies nearly eight out of the nine orders of the total energy range. Even though the optimized response of Rtotal is constrained between 0.89 and 1.1 in the energy range of 0.01 eV-20 MeV, it is suitable for obtaining the broad neutron spectrum of fluence with good accuracy.     

50MeV／u^12C离子实验靶区中子注量率的测量

用阈探测器中子活化法测量了50MeV/u~(12)C离子实验靶区出射的热中子以及E_n分别大于6、11、20、50MeV的中子注量率。     

55MeV/u 40Ar17+离子在生物等效材料中产生的核碎片

利用HIRFL（兰州重离子研究装置）产生的55MeV/u的^40Ar^17 离子束，在辐照生物学实验终端，测量了其经过1.5mm厚有机玻璃后三个不同角度的碎片分布情况，探索了应用CsI(Tl) 快塑料闪烁探测器组成的Phoswich探测器研究重离子在生物材料中产生的核碎片角分布测量的可行性，结果表明这种实验方法是可行的，实验结果令人鼓舞，本工作为进一步的实验积累了可靠的经验。