Track structure and energy deposition distribution of heavy ions in liquid water

ＴｒａｃｋｓｔｒｕｃｔｕｒｅａｎｄｅｎｅｒｇｙｄｅｐｏｓｉｔｉｏｎｄｉｓｔｒｉｂｕｔｉｏｎｏｆｈｅａｖｙｉｏｎｓｉｎｌｉｑｕｉｄｗａｔｅｒＬｉＱｉａｎｇ（李强），ＷｅｉＺｅｎｇ－Ｑｕａｎ（卫增泉），ａｎｄＭａＳｈｏｕ－Ｗｕ（马受武）（Ｉｎｓｔｉｔｕｔ...

Forward-backward multiplicity correlations 4.5 A GeV/c ^16O-emulsion interactions

A detailed study of the mechanisms of the emissions of pions and protons in the forward and backward hemispheres in 4.5 A GeV/c oxygen-emulsion interactions has been carried out. The correlations between the multiplicities of secondary charged particles in the backward and forward hemispheres are investigated.

Features of the total disintegration events of heavy emulsion targets caused by 4.5 A GeV/c ^16O

Total disintegration events produced by 4.5 A GeV/c ^16O-AgBr interactions are analysed to investigate the characteristics of secondary charged particles produced in such collisions. The multiplicity distributions of grey, black, and relativistic charged particles can be well represented by Gaussian distribution. The average multiplicity of grey particles is found to increase with the mass of projectile increasing, while that of black particles is found to decrease with the mass of projectile increasing. This result is in good agreement with the prediction of fireball model. Finally, the linear dependence between grey and black particles is observed, but there is no distinct dependence between the production of relativistic charged particles and the target excitation.

Intermittency in 3.7 A GeV ^16O-emulsion interactions

The intermittency effect has been studied for an interaction of 3.7 A GeV ^16O with emulsion using the distributions of both the pseudorapidity intervals and the azimuthal angle intervals of the shower particles emitted in a central rapidity region. The scaled factorial moments, reduced scaled factorial moments and multifractal moments as functions of the bin size in pseudorapidity and in azimuthal angle have been calculated and have revealed the presence of an intermittent behaviour which may be due to the random cascading property of the reaction. The anomalous fractal dimension has been found to increase with the increase of rank of the moment.

Fragmentation in ^16 O-emulsion interactions at 3.7 A GeV

The topology of ^16 O fragmentation at 3.7 A GeV in reactions with emulsion nuclei is presented. The multiplicity distributions of projectile fragments, charged secondaries and their dependences on the projectile residues are discussed.

Evidence of self-affine multiplicity fluctuation of particle production in ^84Kr-emulsion interactions at 1.7 A GeV

Self-affine multiplicity fluctuation is investigated by using the two-dimensional factorial moment methodology and the concept of the Hurst exponent （H）. Investigation on the experimental data of compound particles and target fragments emitted in ^84Kr-AgBr interactions at 1.7 A GeV reveals that the best power law behaviours are exhibited at H=0.7 and 0.6 respectively, and the data for shower particles produced in ^84Kr-emulsion interactions at 1.7 A GeV indicate that the best power law behaviour occurs at H=0.6, all of which show the self-affine multiplicity fluctuation patterns. The multifractality and the non-thermal phase transition occurring during producing the compound particles, the target fragments, and the shower particles in the ^84Kr -AgBr interaction and the ^84Kr-emulsion interaction are also discussed. The multifractality is observed during producing compound particles, target fragments, and shower particles. In the target fragment production, an evidence of non-thermal phase transition is observed, but in the shower particle production and the compound particle production, no evidence of non-thermal phase transition is observed.

New developments at nuclear emulsion experiment

Three new nuclear cmulsion techniques used for measuring emission angles ofcharged particles in central events at ultra-high evergy heavy-ion collisions are fully described.

Helium production from ^84Kr- and ^197Au-emulsion interactions at high energies

The properties of the relativistic helium fragments produced in interactions of ^84Kr at 1.8 A GeV and ^197Au at 10.7 A GeV in emulsion are investigated. The experimental results are compared with those obtained from various projectiles with emulsion collisions at different energies. It is found that the multiplicity distribution of helium projectile fragments （HPFs） is well described by the Koba-Nielsen Olesen （KNO） scaling presentation. The second Mueller moment f2 of the HPF multiplicity distribution is independent of the projectile energy for the same projectile, but it is dependent on the projectile mass number. The value of f2 increases with the increase of projectile mass number Ap. The negative value of f2, when Ap 〈 69, means that the emission of HPFs is anticorrelated, but positive value of f2, when Ap 〉 69, refers to that the emission of HPFs is correlated. The non-zero f2 moment in this experiment implies the strong correlation existing between the HPFs.

Evidence of intermittent fluctuation of target fragments in ^84Kr-AgBr interactions at 1.7 A GeV

Intermittency and fractal behaviour have been studied of emission spectra of target associated fragments from ^84Kr-AgBr interactions at 1.7 A GeV in emission angle space and azimuthal angle space separately. The intermittent behaviour is observed in the two spaces separately. Prom the intermittency exponent, the anomalous fractal dimension dq is calculated and the variation of dq with the order q is investigated. It is found that the anomalous dimensions are found to increase with the order of moments q, thereby indicating the relation of multifractality to production mechanism of target associated fragments.

Interaction of 28Si with Emulsion Nuclei at 4.5 AGeV/c in View of Thermo-Statistical Approach

In this work, we study some changes of nuclear matter in the interactions of 28Si with emulsion nuclei at 4.5 AGeV/c. From the experimental quantities investigated using Tsallis’ statistics, we deduced the temperature, entropy density and non-equilibrium factor of the nuclear medium. These obtained parameters were used to reveal variations in the nuclear matter at the stated interaction energy. The results that came up from this study were compared with their corresponding results obtained from other heavy ion collision experiments at wide energy range.

Slow Particle Production in Nucleus-Nucleus Collisions at Relativistic Energies

In this paper an effort has been made to study the general characteristics of slow particles produced in the interactions of 32S-Em at 200 AGeV to extract the information about the mechanism of particle production. The results have been compared with the experimental results obtained by other workers. The multiplicity distributions of the slow target associated particles (black, grey and heavy tracks) produced by 32S-beam with different targets have been studied. Also several types of correlations among them have been investigated. The variation of the produced particles with projectile mass number and target size has been studied. Also the multiplicity distributions of slow particles with NBD fits are presented and scaling multiplicity distributions of slow particles produced have been studied in order to check the validity of KNO-scaling.

搭载水稻种子被空间重离子击中的定位研究

为了探明水稻种子在空间搭载后发生突变的原因,设计了一个“三明治”式的实验系统,采用CR-39固体核径迹探测器来探测空间离子,并利用实验系统中空间离子径迹与水稻种子的相对位置,来确定被离子击中的种子和部位。

新型的核乳胶探测技术

介绍了三种可以准确、快速、半自动（全自动）测量的核乳胶实验新技术。这些技术特别适合于测量超高能重离子碰撞中心事例中带电粒子的发射角。

核微孔滤膜的制备及其应用

核微孔滤膜是利用重离子辐照高分子材料后，经化学蚀刻而制成它具有真实的孔径和高选择过滤性能，因而得到广泛地应用讨论了核微孔滤膜的制备原理、方法。

重离子束均匀度的测定及治癌束流成形的模拟试验

采用５０μｍ厚聚碳酸酯薄膜、利用核径迹探测技术测得φ４０ｍｍ的２５ＭｅＶ／ｕ４０；Ａｒ１４；离子束的均匀度在散焦情况下为３２．７％，在“散焦＋样品旋转”情况下为５２．４％。还采用多层聚碳酸酯薄膜组件作为肿瘤块等效材料，进行了重离子束治癌束流成形模拟试验，通过对２５ＭｅＶ／ｕ４０；Ａｒ１４；离子束９个间隔的降能来移动其Ｂｒａｇｇ峰位，并在各个峰位上经过光阑赋予不同的束流截面，由不同层面上的截面可以构成一肿瘤块的椭球状。利用这种方法辐照聚碳酸酯薄膜组件，经化学蚀刻处理后，利用离子径迹小孔对普通光柱的透射与衍射，得到了类似于椭球形肿瘤的光球，光球范围就反映了重离子束能损集中的Ｂｒａｇｇ峰作用的部位。

PETP固体径迹探测器的性能研究

报道了聚乙烯对苯二酸酯（简称PETP）固体核径迹探测器时裂变碎片记录性能的实验研究．在改变温度、蚀刻时间和蚀刻液浓度等条件下测量了裂变碎片径迹平均直径的变化。实验结果表明：蚀刻液温度的变化对裂变碎片径迹的影响最大；而浓度和蚀刻时间的影响不大.同时用低能16O重离子辐照PETP探测器，并得到了它的标定曲线．

液态水中重离子径述结构及能量沉积分布的研究

介绍了重离子径述结构及能量沉积分布理论研究的进展情况，给出了重离子ＭｏｎｔｅＣａｒｌｏ计算模型以及电子径迹中的能量沉积几率分布和重离子径向剂量分布等计算结果。

EMU－01国际合作实验的计算机辅助核径迹图像分析

本文简述了我们参加ＥＭＵ－０１国际合作，在美国ＢＮＬＡＧＳ和西欧ＣＥＲＮＳＰＳ进行超高能重离子诱发核反应实验研究的情况，着重报告了我们近年来关于核径迹的计算机辅助图像分析的研究进展。

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测器相似的性质,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。

重离子径迹周围的径向剂量分布

基于径迹结构的δ射线理论，在电子能量２０ｅＶ－２０ＭｅＶ范围内，本文用单一的对数多项式电子射程能量关系式代替分两段拟合的幂函数表达式，并依据重离子与受照射介质的核外电子相碰这时所产生的二次电子的径向通量公式，采用高斯数值积分法，计算了重离子径迹周围的径向剂量分布。用这种方法计算的结果与作者以前用幂函数公式计算的结果相比较，更接近于实验值。