RF system design and measurement of HIRFL-CSRe

An RF system for the CSRe (cooling storage experimental ring) is designed and manufactured domestically. The present paper mainly describes the RF system design in five main sections: ferrite ring, RF cavity, RF generator, low level system and cavity cooling. The cavity is based on a type of coaxial resonator which is shorted at the end with one gap and loaded with domestic ferrite rings. The RF generator is designed in the push-pull mode and the low level control system is based on a DSP+FGPA+DDS+USB inter...

Experimental results of helicon sources

Helicon plasma source is known as an efficient generator of uniform and high density plasma. A helicon plasma source was developed for the investigation of plasma striping and plasma lens at the Institute of Modern Physics, CAS. In this paper, the characteristics of helicon plasma have been studied by using Langmuir four-probe and a high plasma density up to 3.9×1013 /cm3 has been achieved with the Nagoya type III antenna. In the experiment, several important phenomena have been found: (1) for a given magnetic induction intensity, the plasma density became greater with the increase of RF power; (2) the helicon mode appeared at the RF power between 300 W and 400 W; (3) the plasma density gradually tended to saturation as the RF power increased to the higher power; (4) a higher plasma density can be obtained by a good matching between the RF power and the magnetic field distribution. The key issue is how to optimize the matching between the RF power and the magnetic field. Moreover, some tests on the extraction of ion beam were performed, and the preliminary results were given. The problems which existed in the helicon ion source will be discussed and the increase in beam density will be expected by extraction system optimum.

液-液萃取从Th中分离Ac

用234Th、228Ac和139Ce+3做示踪剂,二(2-乙基己基)磷酸做萃取剂,研究了初始HNO3浓度对234Th、228Ac和139Ce+3萃取效率的影响。发现在广泛的酸度范围内,234Th均能被定量地萃取;当HNO3浓度大于2.0mol/L时,228Ac和139Ce3+的萃取效率下降到2%以下。研究了震荡时间对234Th萃取效率的影响,数据显示,1min便可达到萃取平衡。从含大量钍的溶液中分离痕量Ac的实验结果显示,用二(2-乙基己基)磷酸-苯的萃取流程,可使Ac与大量的钍分离,同时Ac的损失又较小。

~(229)Ac具有较小的八极形变性质

通过 1 4MeV中子引起的2 32 Th(n ,α)反应产生2 2 9Ra ,由放射化学分离和γ(X)谱学方法 ,研究了2 2 9Ra到2 2 9Ac的低位态能级。分析结果表明 ,2 2 9Ac具有较小的八极形变性质

多通道AC电源控制器的研制

简要介绍多通道AC电源控制器。该控制器是一个多路程控开关设备,它由计算机进行控制。该仪器是为一个220V交流电源供电系统自动控制与监视系统设计研制的,是该系统的关键前端设备。

~(230)Acβ-延发裂变概率的测定

由60MeV/μ18O离子照射天然钍靶所引起的232Th-2p反应产生230Ra,通过放射化学分离方法从被照射的靶中提取出镭元素并制成薄源,经230Ra230Ac得到230Ac.用云母裂变径迹探测器和PHGeγ射线探测器对来自源中的裂变碎片和γ谱进行记录和测量,借助于所测得的两个裂变事件和γ谱,鉴别了β-延发裂变核230Ac,得到了它的β-延发裂变概率为（1.19±0.85）×10-8.

~(230)Ac β延发裂变

本文叙述了远离beta稳定线新核素合成尤其是beta延发裂变研究的重要意义,介绍了beta延发裂变先驱~(230)Ac的搜索及其延发裂变几率的测定。

~(230)Ac的β延发裂变

用 6 0MeV/u18O离子轰击ThO2 ,通过多核子转移和靶的耗散碎裂反应产生2 3 0 Ra。利用放射化学分离技术 ,将镭与钍及其它反应产物分离并制备成薄镭源。该源对云母裂变径迹探测器暴光 ,用高纯锗探测器测量镭源的γ活度 ;用氢氟酸溶液对云母箔进行蚀刻 ,使用光学显微镜观测云母箔中的裂变径迹。首次观测到了可能来自2 3 0 Acβ延发裂变的两个事件 ,获得它的 β延发裂变几率为 (1 19± 0 85 )× 10 -8。

~(230)Acβ延发裂变的观测(英文)

搜索了２３０Ａｃβ延发裂变．由 ６０ＭｅＶ／ｕ１８Ｏ离子照射２３２Ｔｈ，通过多核子转移反应产生２３０Ｒａ．经放射化学分离和薄的２３０Ｒａ→β－２３０Ａｃ源的制备，获得了 １０８ 个２３０Ａｃ原子．该源对云母裂变径迹探测器曝光．借助于所测的γ能谱和两个裂变事件，鉴别了β延发裂变核２３０Ａｃ，得到了它的β延发裂变几率为（１． １９± ０．８５）× １０－８．

Single-electron capture in keV Ar15+...18++He collisions

Single-electron capture in 14 keV q(-1) Ar15+...18++He collisions is investigated both experimentally and theoretically. Partial cross sections and projectile scattering angle dependencies have been deduced from the target ion recoil momenta measured by the COLTRIMS technique. The comparison with close-coupling results obtained from a two-centre extension of the basis generator method yields good overall agreement, demonstrating the applicability of close-coupling calculations to collision systems involving highly charged ions in charge states up to 18+.

beta-delayed fission of Ac-228

The basic process of an exotic decay mode namely P-delayed fission is simply introduced. The progress status of the study in the world is essentialized. The observation of P-delayed fission of Ac-228 is reported. The radium was radiochemically separated from natural thorium. Thin Ra sources in which Ac-228 was got through Ra-228 ->(beta-) Ac-228 were prepared for observing fission fragments from beta-delayed fission Ac-228. They exposed to the mica fission track detectors, and measured by an HPGe gamma-ray detector. The beta-delayed fission events of Ac-228 were observed and its beta-delayed fission probability was found to be (5 +/- 2) x 10(-12).