Acquisition of a femtosecond laser ablation system

0901938 Johnson该提案寻求6万美元的资金，用于部分购买飞秒激光烧蚀系统（fsLA），该系统将用作威斯康星大学麦迪逊分校放射性同位素实验室内现有多收集器ICP-MS系统的样品引入系统。该大学将出资35.5万美元，NASA将出资6万美元用于购买。同位素测量可以通过更短波长、更快脉冲宽度的激光烧蚀系统来改进。具有深紫外波长和飞秒脉冲宽度的系统开始在地球科学界投入使用。最近的研究表明，放射性同位素比值与元素，如Sr，Pb和Hf更好地保存从源材料烧蚀时，使用fsLA。初始实验的主要目标是测量由微生物Fe 3+还原产生的单个碳酸盐中的Fe同位素。fsLA系统将是必要的，梳理出铁分馏因素，这将是不可能与散装分析。由于Fe同位素在溶解过程中倾向于断裂，因此对块状碳酸盐的测量特别具有挑战性。当进行连续的酸消化时，效果是明显的。fsLA系统应允许对单个碳酸盐进行分析，以减轻这种偏倚。PI提出了相当多的证据，支持fsLA系统的微探针或西姆斯分析。建议将西姆斯与fsLA结合分析。fsLA系统将为UW-M提供广泛的分析可能性。学生和博士后将能够使用该系统。虽然铁同位素将是最初的焦点，沉积和火成岩地球化学将受益于较短的脉冲激光烧蚀。锆石U-Pb和Hf分析将成为可能。与UW-M稀有气体实验室的合作努力也将是显而易见的。

0901938JohnsonThis proposal seeks funding of $60K for partial purchase of a femtosecond laser ablation system (fsLA) to be used as an sample introduction system on an existing multi-collector ICP-MS system within the Radiogenic Isotope Laboratory at UW-Madison. The University will contribute $355K and NASA will contribute $60K toward the purchase. Isotope measurements may be improved by shorter wavelength, faster pulse-width laser ablation systems. Systems with wavelengths in the deep UV and femtosecond pulse widths are beginning to be fielded in the geoscience community. Recent studies show radiogenic isotopes ratios with elements like Sr, Pb and Hf are better preserved from source material when ablated using fsLA. The prime goal for initial experiments is measuring Fe isotopes in individual carbonates produced by microbial Fe3+ reduction. The fsLA system will be necessary to tease out Fe fractionation factors which would not possible with bulk analyses. Measurements with bulk carbonates is particularly challenging because Fe isotopes tend to fractionate during dissolution. The effect is noticeable when sequential acid digestions are performed. The fsLA system should allow individual carbonates to be analyzed mitigating this bias. The PIs present considerable evidence to support the fsLA system over microprobe or SIMS analyses. Combination analysis with both SIMS and fsLA is suggested. The fsLA system will offer a wide range of analytical possibilities to UW-M. Students and post-docs will be able to utilize the system. While Fe isotopes will be initial focus, sedimentary and igneous geochemistry will benefit from shorter pulse laser ablation. Zircon U-Pb and Hf analyses will be possible. Collaborative efforts with the Rare Gas Laboratory at UW-M will also be evident.***