Measurement of electromagnetic moments of unstable nucleiィイD116ィエD1NィイD2g.sィエD2

不稳定核电磁矩的测量D116D1ND2g.sD2

• 批准号: 10640270
• 负责人: IZUMI Hideaki
• 金额: $ 2.18万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640270/
• 关键词: snowball; unstable nuclei; magnetic moment; spin polarization; relaxation time; liquid hellium; ion trap; superfluid; 核磁気モーメント; 核構造; 超流動ヘリウム

Several anomalous features have been reported for light unstable region nuclei, suggesting that nucleons at large neutron excess may form a bound system whose behavior is radically different from nuclei of the well explored region near stability. Thus, it is challenging to carry out a systematic study of nuclear structure this region of nuclei with microscopic probes such as nuclear moments.However, in case neuclei have second order lifetime as ィイD116ィエD1NィイD2g.sィエD2., the preservation of spin orientation is important for the magnetic moment measurements for unstable nuclei.In order to overcome this difficulty, we propose to use a new type of stopper material; superfluid helium. When impurity ions are introduced into superfluid helium, large fraction of them survive being charged 1+ because of the highest ionization potential of helium atom (24.6 eV), and an aggregate of helium atoms is formed surrounding the ion due to electrostriction. This micro-structure is called "snowball". The h … More ighly symmetric structure of the snowball may cause negligibly small electromagnetic fields on the ion. It is hopeful stopper material for the measurement of nuclear moments for some specific nuclei.And also, a part of implanted ions are neutralized during their stopping process in hellium. This part is also hopeful stopper material, because the electromagnetic field surrounding neutralied atoms are averaged to small by thermal diffusion of hellium.The snowballs are positionally separated from neutral atoms under electoric field, and distinguished in these decay position by position sensitive hodoscopes.Therefore, it is possible to measure various properties, such as spin relaxation time, of each part independently.It is necessary to grasp behavior of ions in liquid helium in order to employ the liquid hellium as stopper material. In order to grasp behavior of ions in liquid helium, experiments were performed at RCNP in Osaka.To observe the motions of impurities ions, the decay vertex is determined by extrapolating the β-ray hit position in the both two plane hodoscopes. We succeded to directly observe a trajectory of Snowballs for the first time by extracting Snowballs from neutrals with a static electric field. And also this method is useful for material science by the observation of nature of quantum liquid by motion of radioactive impurities. Less

轻不稳定区的核有几个异常的特征，这表明在大的中子过剩下的核子可能会形成一个束缚系统，其行为与稳定区附近的核完全不同。因此，用诸如核矩之类的显微探针对核的这一区域的核结构进行系统的研究是具有挑战性的，然而，如果核具有二级寿命如λ D116 λ D1N λ D2g. s λ D2，自旋取向的保持对于不稳定核的磁矩测量是很重要的。2为了克服这个困难，我们提出使用一种新型的阻止材料：超流氦。当杂质离子被引入到超流氦中时，由于氦原子的最高电离势（24.6eV），大部分杂质离子以1+电荷存活，并且由于电致伸缩，在离子周围形成氦原子的聚集体。这种微结构被称为“雪球”。的h ...更多信息 雪球的高度对称结构可能在离子上引起可忽略的小电磁场。同时，注入离子在停止过程中也有一部分被中和。这部分也是很有希望的阻止材料，因为通过氦的热扩散，中性原子周围的电磁场被平均到很小，在电场作用下，雪球与中性原子在位置上分离，并在这些衰变位置上被位置敏感的振迹仪区分，因此可以测量各种性质，如自旋弛豫时间，为了采用液氦作为塞子材料，必须掌握离子在液氦中的行为。为了掌握离子在液氦中的行为，在大坂的RCNP进行了实验，通过外推β射线在两个平面内的入射位置来确定衰变顶点，以观察杂质离子的运动。我们成功地直接观察到了雪球的轨迹，第一次从中性与静电场提取雪球。这种方法也可用于材料科学中通过放射性杂质的运动来观察量子液体的性质。少