We fabricated a set of 64 step height standards, each containing four parallel plateaus offset by three steps of nominally 10 µm, 50 µm, and 100 µm, respectively, and each separated by 18° ramps. The form factor of these standards makes them conducive for introduction into general and forensic-specific areal three-dimensional (3D) surface topography microscopes used in firearm and toolmark evaluations. Each standard is an aluminum cylinder 21.5 mm in diameter and 25 mm tall, similar in diameter of a 12-gauge shotgun shell. The certified step height standards enable customers to calibrate a microscope’s z-axis amplification coefficient (vertical scale) and linearity deviation in addition to implementing statistical quality control methods. This publication provides details on the source and preparation of these standards as well as the use of coherence scanning interference microscopy to calibrate the step heights. The uncertainty budget is also described. (Publisher abstract provided.)
Certification of Standard Reference Material 2323: Step Height Standard for Areal Surface Topography Measurement
NCJ Number
310678
Date Published
September 2024
Length
20 pages
Abstract
Date Published: September 1, 2024