PARIS - Proton cApture Reactions in type Ia Supernovae

重元素的起源问题是有关宇宙物理学尚未解决的主要问题之一。虽然整体情况似乎很清楚，但仔细研究这个复杂的话题，却发现了许多具有挑战性的问题。一个特别令人费解的例子是产生大约35种富含质子的低丰度同位素，这些同位素不能在中子捕获反应中产生，即所谓的p核。最轻的可能是由Ia型超新星发生的一系列质子俘获反应产生的。对相关反应截面的精确实验知识是调查这是否是一幅真实画面的关键。如果是这样的话，p核的核合成可以用来观察Ia型超新星的内部，因为它限制了它们的天体物理参数，因此，可以作为更好地理解这些宇宙标准蜡烛的物理的工具。这个Emmy Noether的提议旨在建立实验技术来研究这些高强度质子束的质子捕获反应。利用法兰克福歌德大学FRANZ设施的高效4π BaF2量热计测量90Zr（p,γ）和91Nb（p,γ）反应，研究Ia型超新星中最丰富的p核92Mo的产生。需要进行FRANZ的扩展和大功率的开发，如果91Nb不稳定，将进行样品。之后，FRANZ将成为世界上独一无二的测量最高质子强度质子诱导反应的设备。

The question about the origin of the heavy elements is one of the major unsolved problems concerning the physics of the Universe. While the overall picture seems clear, a closer inspection of this complex topic has opened up many challenging questions. An especially puzzling case is the production of about 35 proton-rich, low-abundant isotopes, which cannot be produced in neutron capture reactions, the so-called p nuclei. The lightest ones might be produced by a series of proton capture reactions occurring in type Ia supernovae. A precise experimentally based knowledge of the relevant reaction cross sections is the key to investigate whether this is a realistic picture. If so, the nucleosynthesis of the p nuclei can be used to observe the interior of type Ia supernovae as it constrains their astrophysical parameters and, therefore, to serve as a tool to better understand the physics of these cosmological standard candles. This Emmy Noether proposal aims at establishing the experimental techniques to investigate these proton capture reactions with high intensity proton beams. The production of the most abundant p nucleus 92Mo in type Ia supernovae will be studied by measuring the reactions 90Zr(p,γ) and 91Nb(p,γ) with a high efficient 4π BaF2 calorimeter at the FRANZ facility at Goethe University Frankfurt. The needed extensions of FRANZ and the development of high-power, in case of 91Nb unstable, samples will be performed. Afterwards, FRANZ will be a worldwide unique facility to measure proton-induced reactions with highest proton intensities.