Radiofrequency plasma ion source for SIMS

自2014年以来，海德堡大学地球科学研究所一直在运行高分辨率离子微探针。该仪器在德国大学系统中独一无二，可以高精度定量固体中微米至纳米级的同位素和元素分布。为了进一步实现基于地球和环境科学中同位素敏感微量分析的变革性研究，需要一种新的高亮度射频（RF）等离子体离子源。这种类型的离子源已经在商业上可获得，因为只有几年，它提供了多个优点相比，常规使用的duoplasmatron作为一次离子源的正二次离子分析：高稳定性，低维护在常规操作期间，和增强的一次离子密度。稳定的一次离子发射提高了分析精度，而较高的一次离子密度直接增强了给定射束直径下的二次离子产生，反之亦然，使得能够在相同的一次离子强度下使用较小的射束。这允许根据需要优化横向光斑尺寸，以针对初级光束强度解析材料特定结构，从而控制灵敏度、精度和分析持续时间。此外，同位素微量分析目前无法触及的精细结构将首次变得可访问。新的研究领域是地质和宇宙学时间尺度的量化，这些时间尺度可以通过分析矿物中的长寿命和短寿命同位素衰变系统来重建，这些矿物通常是分区的。重要的应用包括研究早期太阳系过程（陨石研究）、俯冲起始和造山作用（原地U-Th-Pb岩石年代学）以及活火山岩浆演化的持续时间（辅助矿物的不平衡定年和主要矿物相中微量元素的扩散模型）。此外，可以以前所未有的空间分辨率绘制地质记录中的微量元素分布图，以尽可能高的时间分辨率重建古环境条件（例如，超微化石、洞穴沉积物）。海德堡的离子微探针设施是一个基石实验室，在一个池的国家的最先进的微观分析仪器针对地质材料（扫描电子显微镜与相关的显微拉曼，电子微探针，背散射电子衍射，触针轮廓术，传统和共焦光学显微镜）。高级同位素微量分析是西姆斯的一个独特领域，将补充这一仪器库，并继续向地球科学和邻近学科的广泛用户群提供。

Since 2014 a high resolution ion microprobe has been operating at the Institute of Earth Sciences at Heidelberg University. Unique within the German university system, this instrument allows high-precision quantification of isotopic and elemental distributions in solids at the micro- to nanoscale. To further enable transformative research based on isotope-sensitive microanalysis in the Earth and environmental sciences, a new high-brightness radiofrequency (RF) plasma ion source is required. This type of ion source has been commercially available since only a few years, and it offers multiple advantages compared to the conventionally used duoplasmatron as the primary ion source for positive secondary ion analysis: high stability, low maintenance during routine operation, and enhanced primary ion density. Stable primary ion emission improves analytical precision, whereas the higher primary ion density directly enhances secondary ion production at a given beam diameter, or vice versa enables use of a smaller beam at the same primary ion intensity. This allows optimization of lateral spot dimensions as required to resolve material-specific structures against primary beam intensity, which controls sensitivity, precision, and analysis duration. Moreover, fine structures presently out of reach for isotopic microanalysis will become accessible for the first time. Novel fields of research are the quantification of geological and cosmological timescales that can be reconstructed from analysis of long- and short-lived isotope decay systems in minerals, which are frequently zoned. Important applications include the investigation of early solar system processes (meteorite studies), subduction initiation and orogenesis (in-situ U-Th-Pb petrochronology), and duration of magma evolution at active volcanoes (disequilibrium dating of accessory minerals and diffusion modelling of trace elements in major mineral phases). In addition, trace element distributions can be mapped at unprecedented spatial resolution in geological records to reconstruct paleoenvironmental conditions at the highest possible temporal resolution (e.g., nannofossils, speleothems). The ion microprobe facility at Heidelberg is a cornerstone lab within a pool of state-of-the-art microanalytical instrumentation targeting geomaterials (scanning electron microscopy with correlative micro-Raman, electron microprobe, backscattered electron diffraction, stylus profilometry, conventional and confocal optical microscopy). Advanced isotopic microanalysis, which is a unique domain of SIMS, will complement this instrument pool and continue to be accessible to a broad user base from the geosciences and adjacent disciplines.