MRI: Acquisition of a Multi-collection Detector System for the Cameca IMS 1280 in the Northeast National Ion Microprobe Facility

这项重大研究仪器(MRI)计划奖提供资金，用于将东北国家离子微探测器设施(NENIMF)运营的Cameca IMS 1280离子微探测器升级为多收集探测器。二次离子质谱仪(SIMS)是一种功能强大的测定固体物质元素和同位素组成的微量分析技术，在地球、海洋和行星科学中有着广泛的应用。26年来，NENIMF一直作为一个高生产率的、由NSF支持的国家基金运作，并配备了非常适合帮助地球科学界充分利用多收集器SIM的仪器和人员。升级的具有多收集能力的IMS 1280将完成NENIMF，成为服务于美国地球科学界的尖端SIMS设施，其成本仅为购买新Cameca IMS 1300-HR3(约700万美元)的一小部分。NENIMF IMS1280作为硅酸盐玻璃、玻璃包裹体和名义上无水矿物中挥发性元素浓度的高质量数据的主要来源，在地球科学界确立了一个重要的利基地位。通过将现有的专业知识与在相同地点分析光稳定同位素的能力相结合，将利用到多收集的升级，从而使我们能够为该设施的用户提供令人兴奋和创新的新的SIMS应用。拟议的升级将极大地加强对喷发前岩浆挥发物质的研究，这是对火山爆炸性的重要控制，以及固体地球中的挥发物质(特别是硫)、宇宙化学、氧同位素测温、生物成因碳酸盐和生物地球化学的研究。Cameca IMS 1280是一台大半径磁扇区的双聚焦质谱仪，离子光学经过优化，在不显著损失二次离子强度的情况下达到6000的质量分辨率。从1998年开始，越来越多的IMS1270/1280离子微探测器配备了同时测量多达五个同位素的能力(多次收集)。与单一收集相比，多收集具有许多显著的优势。首先，它提高了数据收集的效率，从而最大限度地减少了仪器漂移的影响。例如，测定硫化物中S或硅酸盐中氧的同位素组成所需的时间从单次采集的每个点约12分钟减少到多次采集的每个点仅4分钟。这导致了准确度和重现性的显著提高，因为仪器漂移可以通过样品之间更高频率的标准分析来校正。其次，同时测量多个同位素的能力通过将初级离子束的不稳定和漂移的影响降至最低，显著提高了数据质量。例如，在NENIMF单采集系统上对硫化物标准的32S/34S测量具有0.07-0.12RSE(相对标准误差)的典型精度和~0.6‰2RSD(相对标准偏差)的点对点重现性(准确度)。在同一标准下，多采样器分析的精密度为0.02~0.03RSE，精密度为0.1RSD(‰2RSD)。第三，也是最重要的是，多重收集允许对H、C、O、S和氯等轻元素的稳定同位素进行高精度的原位分析。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This Major Research Instrumentation (MRI) Program award provides funds to upgrade the Cameca IMS 1280 ion microprobe operated by the Northeast National Ion Microprobe Facility (NENIMF) with a multi-collection detector. Secondary ion mass spectrometry (SIMS) is a powerful micro-analytical technique for determining the elemental and isotopic compositions of solid materials that has broad applications to earth, ocean, and planetary sciences. The NENIMF has operated as a highly productive, NSF-supported National Facility for twenty-six years and is equipped with instrumentation and personnel that are ideally suited to help the geoscience community take full advantage of multi-collector SIMS. An IMS 1280 upgraded with multi-collection capability would complete the NENIMF as a cutting-edge SIMS facility serving the US geoscience community for a fraction of the cost of purchasing a new Cameca IMS 1300-HR3 (~$7 million). The mono-collection NENIMF IMS 1280 has established an important niche in the geoscience community as a major source of high-quality data on volatile element concentrations in silicate glasses, glass inclusions, and nominally anhydrous minerals. The upgrade to multi-collection will be leveraged by combining this existing expertise with the capability to analyze light stable isotopes on the same spots and, thereby, allow us to provide exciting and innovative new SIMS applications for users of the facility. The proposed upgrade would greatly enhance studies of pre-eruptive magmatic volatiles, which represent an important control on volcano explosivity, as well as volatiles (especially sulfur) in the solid Earth, cosmochemistry, oxygen isotope thermometry, biogenic carbonates, and biogeochemistry.The Cameca IMS 1280 is a double focusing mass spectrometer with a large radius magnetic sector, and ion optics optimized to attain a mass resolving power of 6000 without significant loss of secondary ion intensity. Starting in 1998, an increasing number of IMS 1270/1280 ion microprobes have been equipped with the capability to measure up to five isotopes simultaneously (multi-collection). Multi-collection has a number of significant advantages over mono-collection. First, it increases the efficiency of data collection and – thereby – minimizes the effect of instrumental drift. For example, the time required to determine the isotopic composition of S in sulfides or O in silicates is decreased from approximately 12 minutes per spot using mono-collection to only 4 minutes per spot by multi-collection. This leads to significant improvements in accuracy and reproducibility because instrumental drift can be corrected for through a much higher frequency of standard analyses between samples. Second, the ability to measure multiple isotopes simultaneously leads to a significant increase in data quality by minimizing the effects of instability and drift of the primary ion beam. For example, the 32S/34S measurements on sulfide standards on the NENIMF mono-collection system have a typical precision of 0.07-0.12 ‰ 2RSE (relative standard error) and a spot to spot reproducibility (accuracy) of ~0.6 ‰ 2RSD (relative standard deviation). Multi-collector analysis on the same standards have a precision of 0.02-0.03 ‰ 2RSE and accuracy 0.1 ‰ 2RSD. Third – and most importantly – multi-collection allows for high-precision in situ analysis of stable isotopes of light elements such as H, C, O, S, and Cl.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.