A Tool for Evaluating Systematic Errors in Transmission-Mode X-ray Absorption Fine Structure due to Sample Preparation

X-ray Absorption Fine Structure (XAFS) is a premier method for studying the element-specific

local electronic and atomic structure. Several decades of effort have led to strong theoretical

modeling supported by community-standard tools for processing data and fitting to theory.

However, XAFS measurements themselves require care in sample preparation. We present here

the ERIS software package, with the goal of allowing easy estimates of the relationship between

sample preparation and the magnitude of resulting systematic errors when performing

transmission-mode XAFS. ERIS allows the user to load raw data with incident flux I0 and

transmitted flux IT and then evaluate the independent or combined effects of the two dominant

sample-preparation specific sources of systematic error: (1) the effects of sample thickness

combines with monochromator response function, and (2) the consequences of pinholes or other

sample irregularities. ERIS will help the XAFS community both by helping design more reliable

experiments and also by providing quantitative bounds for possible systematic errors.