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Transport and Extraction of Radioactive Ions in Superfluid Helium

超流氦中放射性离子的传输和提取

基本信息

批准号：
14540283
负责人：
TAKAHASHI Noriaki
金额：
$ 2.18万
依托单位：
Osaka Gakuin University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540283/
关键词：
Superfluid Helium Impurity Ions Radiation Detection Method Snowball Nuclear Polarisation Extraction of Positive Ions Transport Phenomena Potential Barrier

项目摘要

Described here are experiments on the transport under electric field and the extraction of impurities from the surface of superfluid helium. As impurities we introduced radioactive heavy ions into helium. We established an experimental method of production, transport and extraction of ions in superfluid helium by using radiation detection method. With this method we tackled with determination of extraction probability, its dependence on temperature and barrier height at the interface of liquid-vapour phases.The improvements realised were ; 1.extraction potential barrier for the positive ions has been determined for the first time and this is almost equivalent for the extraction of electrons. 2.The snowball production rate at the 215Po source has been improved by applying higher electric field on the surface of the source. 3.The extraction has become more effective by using pulsed second sound for raising locally and instantaneously the surface temperature. We attained the precise determination of probability, its temperature dependence on barrier height. Nuclear spectroscopy experiments with radioactive nuclear beams have been developed further in parallel with these.Rich variety of heavy-ion reaction products will be stopped in superfluid helium and emerge as ultra-cold (zero- energy) radioactive beams. It is expected that this novel method is applicable in the new projects planned in the world. The GSI Darmstadt is counted as one of such institutions.

本文介绍了超流氦在电场作用下的输运和表面杂质的萃取实验。作为杂质，我们将放射性重离子引入氦中。建立了一种利用辐射检测法研究超流氦离子产生、输运和提取的实验方法。用该方法解决了萃取概率的确定、萃取概率与液气界面温度和势垒高度的关系。实现的改进是；1.首次确定了正离子的萃取势垒，这几乎等同于电子的萃取势垒。2.通过在215Po源表面施加较高的电场，提高了源的雪球产生率。3.利用脉冲二次声提高局部和瞬时地表温度，提高了提取的效率。我们获得了概率的精确测定，它的温度依赖于势垒高度。与此同时，放射性核束的核光谱实验也得到了进一步的发展。丰富多样的重离子反应产物将在超流氦中停止，形成超冷（零能）放射性束流。这种新方法有望在世界范围内的新工程中得到应用。达姆施塔特GSI就是这样的机构之一。