Nuclear asrophysics with low energy beams of short-lived nuclei

短寿命原子核低能束的核天体物理学

基本信息

批准号：
62540206
负责人：
SHIMODA Tadashi
金额：
$ 1.22万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62540206/
关键词：
Ion-Trapping In Liquid Helium Long Lifetime Of Trapping Ion-Source For Beams Of Radio-Active Nuclei Small Beam Emittance Thermo-Nuclear Reactions Via Radioactive Nuclei 液体ヘリウム中のイオンイオンの閉じ込め閉じ込め効率取り出し効率天体熱核反応

项目摘要

We have investigated the possible use of liquid helium as an effective ion-source for beams of radio-active nuclei, which open up studies of nuclear synthesis via reactions associated with unstable nuclei under environments of very high temperature and high density such as in novae. An ion introduced into the liquid helium gathers many helium atoms around itself due to the electrostriction and the ion is trapped in the cluster of helium atoms. This charged cluster is referred to as "snowball" When the ions of radioactive nuclei produced in nuclear reactions are stopped and trapped in very low temperature liquid helium, the extracted beams from the liquid will have very small emittance.The feasibility of such ion-source relies on achieving (i) the high efficiency in forming the snowball, (ii) long lifetime of the snowball and (iii) high efficiency in extracting the ions from the liquid. We have examined the characteristics of the snowball in the following experiments; ions of ^<14>N with energy of 90 MeV are implanted into the liquid helium, and the ion currents have been measured under the electric fields applied in correlation with the beam pulse. The results we obtained are as follows:(1) The lifetime of the snowball was found to be about 700 ms, which is much longer than in the other methods of ion trapping.(2) The ion current depended much on the electron density around the ion in the liquid. This implies that the efficiency in forming the snowball may be increased by decreasing the implantation energy of the ions and by increasing applied field.(3) The mobility of the snowball was much larger in the superfluid helium than in the normal helium. Therefor more rapid control of the snowball is possible in the superfluid. In summary the liquid helium ion-source for the radio-active nuclear beams is quite promising.

我们已经研究了液氦作为放射活性核束的有效离子源的使用，该核的梁通过与不稳定的核相关的反应开放了核合成的研究，在非常高的温度和高密度的环境下，例如Novae。引入液氦的一个离子由于电静止而在自身周围收集了许多氦原子，并且离子被困在氦原子簇中。当核反应中产生的放射性核离子离子被停止并被困在非常低的温度液体氦中时，从液体中提取的束将非常较小的发射率时，这种带电的簇被称为“滚雪球”。这种离子源的可行性很小。这种离子源的可行性。液体。我们在以下实验中检查了雪球的特征。 ^<14> N的离子为90 MeV，将其植入液态氦气中，并且离子电流已在与梁脉冲相关的电场下测量。我们获得的结果如下：（1）发现雪球的寿命约为700毫秒，比其他离子捕获方法更长。（2）离子电流很大程度取决于液体中离子周围的电子密度。这意味着形成雪球的效率可以通过降低离子的植入能和增加施加场来提高。（3）超浮力氦气中雪球的迁移率要比正常氦气大得多。因此，超级流体可以更快地控制雪球。总之，放射活性核束的液氦离子源是非常有希望的。