High-Energy Heavy-Ion Reactions and Polarization in Matter

高能重离子反应中产生的原子核被认为能够维持极化。这项研究的第一阶段是寻找维持大极化的放射性原子核。利用大阪大学和理化学研究所的回旋加速器，雷霍沃特和莱格纳罗的串联加速器来研究这种可能性。GSI的SIS-FRS系统也有效地适用于这些目的。在上述实验室中，对获得持续不清极化的快离子的可能性进行了实验测试；从列格纳罗串联加速器中获得了^<93>Tc等重极化离子，并对其在固体材料中的极化及其保存进行了实验研究。成功地进行了注入液氦，并进一步研究了离子和核极化行为。除了在雪球中保存核极化外，正在研究下列事实。在液氦中，快离子的停止能力是双重的，一方面表现在正常物质和流体中，另一方面表现在超流氦中，维持的范围比前者长得多。这可能是由于在地狱的集体流动。测量是用放射性光束和探测方法进行的。当离子在强电场中运动时，核极化可能被破坏，从而避免被包裹在雪球中。这一现象将进一步研究。

Nuclei produced in high-energy heavy-ion reactions are expected to sustaning polarization. The first stage of this research is to find radioactive nuclei sustaining large polarization. Cyclotrons of Osaka University and Riken, Tandem Accelerators of Rehovot and Legnaro were utilized to investigate the possibility. The SIS-FRS system at GSI was also effective to apply for such purposes.Possibilities of obtaining fast ions sustainig unclear polarization were tested experimentally at above laboratories ; the heavy polarized ions such as ^<93>Tc were obtained from the Legnaro tandem accelerator and the polarization and its preservation in a solid material were experimentally studied.The implantation into liquid helium was successfully carried out and the behavior of ions and nuclear polarization was further studied. In addition to the preservation of nuclear polarization in snowballs the folllowing facts are being studied. The stopping power of fast ions in liquid helium is double valued, one component as in normal matter and fluid, the other manifested in superfluid helium sustaining a range much longer then the former. This may be due to the collective flow in HeII.The measurements were carried out with radioactive beam and beta and alpha detection methods.The nuclear polarizaion may be destroyed when ions move in a strong electric field therefore evading the encapsulation in snowballs.The phenomenon will be further investigated.