A multi-purpose particle detector for measurement of decays of highly-charged ions in storage rings

储存环中离子衰变特性的测量是传统测量技术的补充。它已被证明是一个非常成功的工具，用于同时测量注入储存环中的几十个离子的质量。此外，在储存环中首次发现并测量了只有少量电子或没有电子的离子的奇异衰变模式，即所谓的“高电荷离子”（HCI）。例子是“束缚态β衰变”，它导致一些原子核在完全电离状态下的衰变加速，例如187 Re（75+）的衰变速度比中性状态快10亿倍，而稳定的中性163 Dy在转移到完全电离的66+电荷状态时变得具有放射性并以45天的半衰期衰变。 现代核物理学家的梦想是能够“操纵”物质衰变的速度。核嬗变，将长寿命的放射性废物转化为衰变更快的东西，可以从这些研究中受益匪浅-然而，到目前为止，衰变模式的强烈加速只在少数情况下观察到，这些情况不是放射性废物的主要贡献者。 对于储存环中的测量，需要两种类型的检测器：一种用于在离子在储存环中轨道运行时对离子进行无损检测和识别，另一种用于检测衰变产物，如果它们由于其有限的动量接受而不能储存在储存环中的话。为了无破坏地识别离子和相应的质量测量，使用称为“肖特基拾取器”的设备。为了检测离开环形粒子检测器接受范围的衰变产物，使用望远镜。 我的亥姆霍兹青年研究者研究小组在2010-15年为这一提议奠定了基础。在与慕尼黑工业大学的合作中，我的团队已经建造了原型探测器“CsISiPHOS”（用于储存环中重离子轨道的CsI-硅粒子探测器），并在2015年对其进行了测试和调试。CsISiPHOS是一种多用途探测器，用于探测实验储存环（ESR）和/或收集环（CR）中衰变过程中发射的各种粒子，是FAIR ILIMA（寿命和质量调查）计划的组成部分。探测器必须提供与冷却后环中的束直径相对应的位置分辨率，以及质量A和核电荷Z的唯一粒子识别，以允许等压污染物的清晰分离。 针对该探测器的升级版本提出了几项改进建议，这些改进已在2017/18年提交给FAIR ECE理事会的TDR中进行了描述。如果获得资助，这个新的探测器和新的数据采集系统将用于2021年夏季开始的FAIR第0阶段实验。

The measurement of decay properties of ions orbiting in a storage ring is a complementary path to conventional measurement techniques. It has been proven to be a very successful tool for the simultaneous mass measurement of dozens of ions injected in the storage ring. Also exotic decay modes of ions with only a few or no electrons, so-called "highly-charged ions" (HCI) have been discovered and measured for the first time in storage rings. Examples are the "bound-state beta decay" that leads to an acceleration of the decay of some nuclei in the fully ionized state, e.g. 187Re(75+) decayed 1 billion times faster than in the neutral state, and stable neutral 163Dy becomes radioactive and decays with a half-life of 45 days when transferred into the fully-ionized 66+ charge state. It is a modern nuclear physicists dream to be able to "manipulate" how fast material can decay. Nuclear transmutation, the transformation of long-lived radioactive waste into something that decays faster, could greatly benefit from these studies- however the strong acceleration of decay modes has so far only been observed for a few cases that are not the main contributors of radioactive waste. For the measurements in the storage rings two types of detectors are needed: one for the destruction-free detection and identification of the ions while they orbit in the storage ring, and one detector for the detection of the decay products if they cannot be stored in the storage ring due to its limited momentum acceptance. For the destruction-free identification of the ions and respective mass measurement a device called "Schottky pickups" is used. For the detection of decay products that leave the acceptance of the ring particle detector telecopes are used. The foundation for this proposal has been laid by my Helmholtz Young Investigators Research Group in 2010-15. In collaboration with the TU Munich my group has constructed the prototype detector "CsISiPHOS" (CsI-Silicon Particle detector for Heavy ions Orbiting in Storage rings) and tested and commissioned it with beam in 2015. CsISiPHOS is a multi-purpose detector that has been built to detect various particles emitted in decay processes in the Experimental Storage Ring (ESR) and/or Collector Ring (CR) and is an integral part of the ILIMA (Investigation of LIfetimes and MAsses) program at FAIR. The detector has to provide a position resolution corresonding to the beam diameter in the ring after cooling, as well as unique particle identification in mass A and nuclear charge Z to allow a clear separation of isobaric contaminants. Several improvements have been suggested for the upgraded version of this detector which have been described in the TDR that has been submitted to the FAIR ECE council in 2017/18. If funded, this new detector and the new data aquisition system will be used in upcoming FAIR Phase-0 experiments starting in summer 2021.