MLLTRAP is a double Penning trap mass spectrometer that was initially designed to be located at the Maier-Leibnitz-Laboratory (MLL) in Garching (Germany) for high precision mass measurements of exotic nuclei. A second double-trap assembly, dedicated this time to in-trap $\alpha$ decay spectroscopy, has been developed and is the object of this paper. This assembly can optionally replace the current mass-measurement trap electrode assembly during future spectroscopy campaigns at DESIR/SPIRAL2 in France. Though the previous assembly will be the instrument of choice for high-precision mass measurements, the new double-trap has been designed to be compatible with the ToF-ICR and PI-ICR mass measurement techniques in addition to its initial decay spectroscopy purpose, as it would be a significant operational advantage not to have to switch between assemblies on a regular basis. We have undergone a number of simulations to design this double trap system and estimate its future capabilities. These simulations concern the cooling of ions of interest in the first trap, mass measurements in the second trap and the application of the new Decay and Recoil Imaging (DARING) technique to measure lifetimes of first excited nuclear states populated by $\alpha$ decay. The latter will be described in details in a forthcoming publication and thus the present contribution should be considered as ”part one” of a two-part article on the design and simulation of the upcoming double-trap system for MLLTRAP. While the cooling and measurement techniques presented in this contribution have been extensively described and simulated in the past, this specific double-trap has a unique geometry, as the central electrode of the second trap has been replaced by a cubic arrangement of four Si-strip detectors. We study here the expected impact of this geometry on the mass measurement capabilities of the future trap.

MLLTRAP是一款双Penning阱质谱仪，最初设计为位于Garching（德国）的Maier-Leibnitz-Laboratory（MLL）处，用于外来核的高精度质量测量。第二个双疏水阀组件，这次专用于疏水阀$\alpha$衰减光谱学已经得到发展，并且是本文的目的。在将来的法国DESIR / SPIRAL2光谱研究活动期间，此组件可以有选择地替换当前的质谱捕获阱电极组件。尽管以前的组件将成为高精度质量测量的首选仪器，但新的双重捕集阱已被设计为与ToF-ICR和PI-ICR质量测量技术兼容，此外还具有初始衰减光谱的目的，例如不必定期在组件之间进行切换将是一项重要的运营优势。我们已经进行了许多模拟，以设计这种双阱系统并估计其未来功能。这些模拟涉及第一个阱中目标离子的冷却，$\alpha$衰变。后者将在即将出版的出版物中进行详细描述，因此，本贡献应被视为有关即将进行的MLLTRAP双阱系统设计和仿真的两部分文章的“第一部分”。尽管过去已经广泛描述和模拟了此贡献中介绍的冷却和测量技术，但该特定的双阱具有独特的几何形状，因为第二阱的中心电极已被四个硅带的立方排列所代替探测器。我们在这里研究这种几何形状对未来疏水阀质量测量能力的预期影响。