Nuclear structure at the proton drip line and at ultra high spin

该提案包括两个部分，都涉及极端条件下原子核结构的研究。第一部分是对原子核的研究，其中质子与中子的比率与稳定原子核中的质子与中子比率有很大的不同。在质子滴线上有太多的质子(相对于中子的数量)，不能再加了。就质子中子率而言，这是最稳定的。这项工作将研究具有变形(橄榄球)形状的这类核的性质，并将结果与在稳定核中发现的结果和核模型预测的结果进行比较。这项工作的第二部分涉及研究极高自旋极端时的核结构，就在核因裂变而分裂之前。在这项工作中，我们将集中在这一极端的质量160附近的原子核中配对力的作用。工作的第一部分将在加拿大的TRIUMF实验室进行，2007年将在那里提供一个新的放射束设施和伽马射线光谱仪。这些设施对这项工作至关重要。对于这项工作的第二部分，我们已经获得了使用美国阿贡国家实验室的伽马斯菲尔能谱仪对160Er和邻近原子核进行实验的束流时间。这是世界上唯一可以以非常高的自转速度进行这种类型的详细核结构工作的设施。我们预计这项试验将于2007年上半年进行。这项高自旋工作将与达累斯伯里实验室合作，并将成为一个补充研究计划的一部分，该计划涵盖最高自旋原子核结构的几个方面。

The proposal has two parts both of which concern the study of the structure of nuclei under extreme conditions. The first part is the study of nuclei where the proton to neutron ratio is changed to be very different from that found in stable nuclei. At the proton drip line there are so many protons (relative to the number of neutrons) that no more can be added. This is the extreme of stability in terms of the proton neutron ratio. This work will study the properties of nuclei of this type that have a deformed (rugby ball) shape and compare the results to those found in stable nuclei and those predicted by nuclear models. The second part of the work concerns the study of nuclear structure at the extreme of very high spin, just before the nucleus breaks up due to fission. In this work we will concentrate on the role of the pairing force in nuclei near mass 160 at this extreme. The first part of the work will take place at the TRIUMF laboratory in Canada where a new radioactive beam facility and gamma-ray spectrometer become available in 2007. These facilities are vital for this work. For the second part of the work we have already been awarded beam time for an experiment on 160Er and neighbouring nuclei using the GAMMASPHERE spectrometer at the Argonne National Laboratory, USA. This is the only facility worldwide available to carry out this type of detailed nuclear structure work at very high spin. We expect that this experiment will be scheduled in the first half of 2007. The high spin work will be in collaboration with Daresbury Laboratory and will form part of a complementary research programme covering several aspects of the structure of nuclei at the highest spins.