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在线同位素分离器(ISOL)是北京放射性核束装置(BRNBF)计划的主要设备之一,其中用来产生放射性核素的厚靶为技术关键,它决定了放射性核束的产生效率及总强度,是设计中需重点考虑的。为了提高放射性核素的扩散速度,减少短寿命核素的衰变损失,靶的温度应尽可能高,同时还要保证厚靶在强流辐照条件下的结构完整性。文内讨论了对靶材料的物理、化学性质,靶物质的尺寸形态,靶结构和散热系统设计等方面的要求,列举了几种候选靶材,介绍一个厚靶的物理设计过程,设计了一个石墨靶衬并合理安排厚靶的水冷散热结构,计算了厚靶的三维温度分布情况。计算结果表明,经过精心设计,此厚靶完全能够承受最高达14kW的质子束入射束流功率,可以根据不同靶材的要求将靶的温度控制在1300～2000℃,放射性核素可以迅速扩散,并且被离子源有效地电离和引出,从而获得较高流强的放射性核束。
The online isotope separator (ISOL) is one of the major equipment planned for the Beijing Radionucleating Beam Device (BRNBF). The thick target used to generate radionuclides is a key technology that determines the efficiency and overall intensity of radionuclide beam production. It is important to consider in the design. In order to increase the diffusion rate of radionuclides and reduce the decay loss of short-lived nuclides, the target temperature should be as high as possible while ensuring the structural integrity of the thick target under intense current irradiation. In this paper, the physical and chemical properties of the target material, the size and shape of the target material, the target structure and the design of the cooling system are discussed. Several candidate targets are listed, the physical design process of a thick target is introduced, and a Graphite target lining and reasonably arrange the thick target water cooling structure, calculate the thick target three-dimensional temperature distribution. The calculated results show that the designed thick target can withstand the beam power of proton beam up to 14kW, the target temperature can be controlled at 1300-2000 ℃ according to the requirements of different targets, and the radionuclide can diffuse rapidly. And is effectively ionized and extracted by the ion source to obtain a higher intensity radioactive nuclear beam.