Neutron Induced Charged particle Emission

原子核是由质子和中子组成的。虽然自由中子在自然界中只存在于很短的时间尺度上，但由于它们的不稳定性，中子诱导反应在我们的社会中起着重要的作用。它们的影响范围从癌症治疗中的医学应用到反应堆科学中的纯技术挑战，再到元素起源等基本问题。尽管它们的重要性，只有有限数量的中子诱导反应的研究到目前为止。这对于产生带电粒子的中子诱导反应来说尤其如此。由于这个原因，项目NICE（中子感生带电粒子发射）专注于这些反应的横截面测量。相应的实验需要检测带电的反应产物。它们的物质射程很短，这给实验带来了一些挑战。首先，需要薄的靶，以允许反应产物从样品本身逸出。相应的少量样品核妨碍了截面的测定。因此，需要高中子通量和中子产生靶与探测器之间的短距离来补偿少量的样品核。缺点是探测器中的中子和伽马射线背景很高。将在NICE项目范围内开发一种经过优化的检测装置，以应对这些挑战。这种探测装置与新的中子源FRANZ的结合将提供以前所未有的灵敏度研究各种中子诱导反应的可能性。在该项目中，将对天体物理学上重要的反应33S（n，a）进行测量，以证明在FRANZ安装的新探测器的能力。

The atomic nuclei are made of protons and neutrons. Although free neutrons exist only on short time-scales in nature, because they are unstable, neutron-induced reactions play an important role in our society. Their impact ranges from medical applications in cancer therapy over purely technological challenges in reactor sciences to fundamental questions like the origin of the elements. Despite their importance only a limited number of neutron-induced reactions are investigated so far. This is especially true for neutron-induced reactions producing charged particles. For this reason the project NICE (Neutron Induced Charged particle Emission) focuses on cross section measurements of these reactions. The corresponding experiments require the detection of charged reaction products. They have only a short range in matter, which poses several challenges to the experiment. First of all, thin targets are needed allowing the reaction products to escape from the sample itself. The correspondingly small number of sample nuclei hampers the determination of cross sections. Therefore, high neutron fluxes and a short distance between the neutron-production target and the detector are needed to compensate for the small number of sample nuclei. The drawback is the high background of neutrons and gamma-rays in the detector. A detection setup, which is optimized to deal with these challenges, will be developed within the scope of the NICE Project. The combination of this detection setup with the new neutron source FRANZ will offer the possibility to study a large variety of neutron-induced reactions with unprecedented sensitivity. Within the project a measurement of the astrophysically important reaction 33S(n,a) will be performed to prove the capabilities of the new detector setup at FRANZ.