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

测量存储环中离子的衰变特性是对传统测量技术的补充。它已被证明是一种非常成功的工具，可以同时测量注入存储环中的数十个离子的质量。此外，还首次在储存环中发现和测量了只有很少电子或没有电子的离子的奇异衰变模式，即所谓的高电荷态离子(HCI)。例如，导致某些原子核在完全电离状态下加速衰变的束缚态β衰变，例如，187Re(75+)的衰变速度是中性态的10亿倍，而稳定的中性163Dy在转变为完全电离的66+电荷态时，变得具有放射性并以45天的半衰期衰变。 能够“操控”物质衰变的速度是现代核物理学家的梦想。核形变--将寿命较长的放射性废物转变为腐烂速度更快的物质--可能会从这些研究中获得巨大好处--然而，到目前为止，只在少数不是放射性废物主要贡献者的情况下观察到了衰变模式的强烈加速。 对于存储环中的测量，需要两种类型的探测器：一种用于对在存储环中运行的离子进行无损检测和识别，另一种用于检测衰变产物，如果衰变产物由于其动量接受能力有限而不能存储在存储环中。为了无损地识别离子和相应的质量测量，使用了一种称为“肖特基拾取器”的装置。对于离开环形粒子探测器接受的衰变产物的检测，使用遥视。 这项提议的基础是我的Helmholtz青年调查员研究小组在2010-15年间奠定的。我的小组与慕尼黑理工大学合作，建造了“CsISiPHOS”(CSI-存储环中重离子硅粒子探测器)原型探测器，并于2015年用BEAM对其进行了测试和委托。CsISiPHOS是一种多用途探测器，旨在检测实验存储环(ESR)和/或收集环(CR)衰变过程中释放的各种粒子，是广交会IMIMA(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光束直径相对应的位置分辨率，以及唯一的质量A和核电荷Z中的粒子识别，以允许清楚地分离等压污染物。 已在2017/18年提交给FIRE欧洲经委会理事会的TDR中对该探测器的升级版本提出了几项改进建议。如果获得资金，该新探测器和新的数据采集系统将用于即将于2021年夏季开始的FIRE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.