富中子铜同位素的激发态寿命

该项目通过测量 β 衰变和伽马射线发射，研究铜同位素（特别是 Cu-75 和 Cu-77）激发态的寿命。研究旨在了解价质子与中子数增加之间的量子动力学关系，并将在日本理化学研究所（RIKEN）实验室利用闪烁体阵列开展。申请人需具备实验物理技能，并熟悉 C++、ROOT 和 Python 等编程语言。

Job description: Project description: The copper isotopes count a single proton outside a mostly spherical and rigid nickel core. Therefore they present us with a microscopic laboratory in which to follow the evolution of the quantum numbers of the valence proton, as neutrons are gradually added to the system. Among the intrinsic properties of the nucleus, we intend here to investigate the lifetimes of some of the most salient excited states in these isotopes. If the valence proton can be described as a single and independent particle, the lifetime of the excited state in which it is found would be long (the de-excitation is impeded by the difference of the quantum numbers); if other particles take part in its wave function, either by breaking the core or by the onset of collective modes such as core vibrations, the lifetime would be short (several channels are open for the level to de-excite). During our previous work on Cu-79, however, this picture has turned out to be too simple. Contributions from the magnetic dipole operator add into the electric quadrupole transitions and greatly shorten the observed lifetimes, obscuring the changes in the wave functions. We now plan to extend our efforts to other isotopes in order to gain a better understanding of the underlying mechanism. We shall measure the β decay followed by the emission of a γ ray in the Cu-75 and Cu-77 isotopes. The delay between both signals will directly tell us the lifetime of the excited state, expected to be of the order of some tens of picoseconds. The experiment will take place at the Riken laboratory in Japan with an array of 84 LaBr3 scintillators from an English-Korean collaboration.

Profile and skills required: good understanding of experimental physics C++ & Root & Python data analysis work within an international collaboration reasonably good level of English