Validation data for a scanning electron microscope-energy dispersive spectrometry (SEM-EDS) method for the analysis of common volcanic phases

Introduction This dataset contains data that underlie the development and validation of the quantitative scanning electron microscope-energy dispersive spectrometry (SEM-EDS) analytical routine implemented at the U.S. Geological Survey Cascades Volcano Observatory (CVO). The data comprise SEM-EDS analyses of plagioclase, olivine, pyroxene, magnetite, ilmenite, and volcanic glass reference materials to optimize the analytical setup and document the precision and accuracy of the method. Please cite the associated journal article for references to our analytical routine. Supplemental tables containing the reference material expected concentrations (Tables S1 and S2), summaries of the results of parameter testing (Table S3), and the reproducibility of mineral and glass standards (Tables S4 and S5) are provided together in a single Excel workbook (supplemental summary tables S1-S5.xlsx). The underlying data are contained in separate comma-separated values (csv) files, each with an associated file of field definitions. The information in Tables S3, S4, and S5 is derived from the data reported in Table S6. The contents of each supplemental table are: Table S1: The expected compositions of all mineral standards used for calibration and verification, and a list of the standards used to calibrate each element in each phase. Table S2: The expected concentration of all glass standards. Table S3: A summary of the results of testing the total spectrum counts, process time, and standardized versus standardless quantification. Table S4: A summary of the long-term reproducibility of mineral standards. Table S5: A summary of the glass analyses for which we judged the beam damage to be mitigated. TableS6.csv: All spot and raster analyses of the mineral and glass standards. TableS7.csv: The line scan data used to determine the collimator width. TableS8.csv: The peak resolution data used to compare the process times. Methods summary All data were collected at CVO using a JEOL IT510 W-source SEM, an Oxford Instruments Ultim Max 40 mm2 EDS detector, and the Oxford Instruments AztecLive (OIA) EDS software, version 6.0 SP2 (Oxford Instruments, 2023). Mineral and pure oxide reference materials used for calibration and verification are from the Smithsonian Microbeam Standards Collection (SMS) or purchased from Micro Analytical Consultants (MAC). All materials were mounted in epoxy-filled wells in 25-mm-diameter brass or leucite disks, ground and polished flat using 1 µm diamond followed by 0.25 µm alumina for the final polishing steps, and coated with approximately 20 nm of carbon prior to analysis. Our preferred protocol for mineral analysis utilizes an accelerating voltage of 15 kV, working distance of 10 mm, process time of 16 µs, a beam current scaled to a dead-time of 45–55% (generally produced by a current of 2–3 nA), a 30 µm final aperture, and applies the pulse pileup correction implemented in OIA. At these conditions, typical output count rates were 20–25 kilo-counts per second (kcps). Spectra are collected with 1.5 million total counts (typically acquired within 35 s live time) using 4048 channels with 5 eV per channel. As described in detail in the accompanying article, we performed analyses using 0.25–2.5 x106 total spectrum counts, currents of 0.6–11 nA, process times of 2–16 µs, and point versus area raster analyses to optimize the analytical setup and investigate mitigation strategies for beam damage in volcanic glass. The instrument settings for each analysis are recorded in Table S6. Disclaimers This database, identified as “Data to support a scanning electron microscope-energy dispersive spectrometry (SEM-EDS) method for the quantitative analysis of common volcanic phases”, has been approved for release by the U.S. Geological Survey (USGS). Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, the database is released on condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized use. Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.引言 本数据集包含用于开发和验证美国地质调查局喀斯喀特火山观测站（CVO）所采用的定量扫描电子显微镜-能量色散X射线能谱（SEM-EDS）分析流程的基础数据。数据集涵盖斜长石、橄榄石、辉石、磁铁矿、钛铁矿以及火山玻璃参考物质的SEM-EDS分析结果，用于优化分析配置并记录该方法的精密度与准确度。如需引用本分析流程，请参考相关期刊论文。 包含参考物质预期浓度（表S1和S2）、参数测试结果汇总（表S3）以及矿物和玻璃标样的重现性数据（表S4和S5）的补充表格已整合至单个Excel工作簿（supplemental summary tables S1-S5.xlsx）。原始数据存储于独立的逗号分隔值（CSV）文件中，每个文件均附带对应的字段定义文件。表S3、S4和S5中的信息均源自表S6中报告的数据。各补充表格的内容如下： 表S1：用于校准与验证的所有矿物标样的预期组成，以及各物相中各元素校准所使用的标样清单。 表S2：所有玻璃标样的预期浓度。 表S3：总谱线计数、处理时长、标准化与无标定量分析结果的汇总。 表S4：矿物标样长期重现性的汇总结果。 表S5：经判定束流损伤已得到缓解的玻璃分析结果汇总。 TableS6.csv：所有矿物与玻璃标样的点分析和面扫描分析数据。 TableS7.csv：用于确定准直器宽度的线扫描数据。 TableS8.csv：用于对比处理时长的峰分辨率数据。 方法概要 所有数据均于CVO使用JEOL IT510型钨灯丝扫描电子显微镜、牛津仪器Ultim Max 40 mm²能谱探测器以及牛津仪器AztecLive（OIA）能谱软件（版本6.0 SP2，牛津仪器，2023）采集。用于校准与验证的矿物及纯氧化物参考物质源自史密森尼微束标准品收藏集（SMS），或购自微分析咨询公司（MAC）。所有样品均封装于直径25 mm的黄铜或白榴石圆盘的环氧树脂凹槽中，先以1 µm金刚石磨料进行研磨抛光，最终采用0.25 µm氧化铝完成抛光，并在分析前喷涂约20 nm厚的碳层。 我们推荐的矿物分析方案采用以下参数：加速电压15 kV，工作距离10 mm，处理时长16 µs，束流电流经校准至死时间为45%~55%（通常对应2~3 nA的束流），最终孔径30 µm，并应用OIA软件内置的脉冲堆积校正。在此参数条件下，典型计数率为20~25千计数每秒（kcps）。谱线采集采用4048个通道（每个通道对应5 eV），总计数为150万（通常实时采集时长约35 s）。 如配套论文中详细描述的那样，我们采用0.25×10⁶~2.5×10⁶的总谱线计数、0.6~11 nA的束流电流、2~16 µs的处理时长，以及点分析与面扫描分析相结合的方式，以优化分析配置并探究火山玻璃束流损伤的缓解策略。每次分析的仪器参数均记录于表S6中。 免责声明 本数据库命名为“支持常见火山相定量分析的扫描电子显微镜-能量色散X射线能谱（SEM-EDS）方法”，已通过美国地质调查局（USGS）的发布审批。尽管本数据库经过严格审核且内容基本完整，但美国地质调查局保留根据进一步分析与审核修订数据的权利。此外，本数据库的发布条件为：无论授权使用还是非授权使用，均不得追究美国地质调查局或美国政府因使用本数据库导致的任何损害责任。 尽管这些数据已在美国地质调查局（USGS）的计算机系统中成功处理，但并未对数据在其他用途的展示效果或实用性作出任何明示或暗示的担保，也不保证在所有计算机系统上均可正常使用。发布本数据的行为亦不构成此类担保。对于因不当或错误使用本文所述及/或包含的数据而造成的损失，美国地质调查局或美国政府概不承担责任。 任何贸易、公司或产品名称的使用仅为描述性用途，并不意味着美国政府对此类名称的认可。