Acquisition of a Normal Incidence Electron Gun for the ASU SIMS

小行星9615982 这笔赠款提供了95，210美元，作为亚利桑那州Cameca 3f二次离子质谱仪（西姆斯）购买正入射电子枪（NIEG）的部分费用。 该附件补偿在用带正电的碱金属（即Cs+）离子束溅射的样品的表面上发生的电荷积累，例如分析氧同位素和其他电负性元素（即，H、C、F、Cl、P、S、As、Sb、Se）。 该电子枪的束法线几何形状允许分析容易受到强烈电子轰击损坏的样品，这种强烈电子轰击使用内部设计的斜角电子枪。 添加此附件将允许提高精度（约为100%）。1/mil），并且可能在绝缘体相的氧同位素西姆斯分析的横向分辨率中，并且因此将提供其当前配置的西姆斯的精度的几乎两倍的增加。增加了一个正常的入射电子枪负担得起的精度无疑将使用富有成效的本PI在他的自生粘土矿物的早期成岩作用，岩浆中的挥发性元素预算的基础上的火山岩中的熔融包裹体的硫同位素分析和环境样品中的挥发性微量元素丰度绘图的继续研究。 ***

9615982 Hervig This grant provides $95,210 as partial support of the costs of acquiring a normal incidence electron gun (NIEG)for the Cameca 3f secondary ion mass spectrometer (SIMS) at Arizona State. This accessory compensates for charge buildup that occurs on the surface of samples that are being sputtered with positively charged ion beams of alkali metals (i.e. Cs+), such as is necessary to analyze for oxygen isotopes and other electronegative elements (i.e., H, C, F, Cl, P, S, As, Sb, Se). The beam-normal geometry of this electron gun allows for analysis of samples that are prone to damage from intense electron bombardment that occurs using an oblique angle electron gun that was designed in-house. Addition of this accessory will allow an increase in the precision (to ca. 1 per mil)and perhaps in the lateral resolution of oxygen isotopic SIMS analyses of insulator phases and thus will provide for nearly a factor of two increase in the precision of their currently configured SIMS. The increase in precision affordable with the addition of a normal incidence electron gun will undoubtedly be used fruitfully by this PI in his continued studies of the early diagenesis of authigenic clay minerals, volatile element budgets in magmas based on Sulfur isotopic analyses of melt inclusions in volcanic rocks and mapping of volatile trace element abundances in environmental samples. ***