Focused Ion Beam Milling as a Method for Machining Explosive Crystals**

Abstract Experimental pore collapse studies have traditionally relied on machining methods that are mechanically active and result in rough surfaces, added stresses, and premature material fractures which are a source of experimental error. This work focuses on the method development and the results of adapting the focused ion beam to mill micro and nano‐scale pores with increased geometrical freedom into explosive crystals. Results include developing a simplified mathematical relationship between the electron beam energy and mill rate, assessments of pore quality, and material and machine‐specific optimal milling parameters.