title: Introducing measure-by-wire, the systematic use of systems and control theory in transmission electron microscopy.
abstract: Transmission electron microscopes (TEMs) are the tools of choice for academic and industrial research at the nano-scale. Due to their increasing use for routine, repetitive measurement tasks (e.g., quality control in production lines) there is a clear need for a new generation of high-throughput microscopes designed to autonomously extract information from specimens (e.g., particle size distribution, chemical composition, structural information, etc.). To aid in their development, a new engineering perspective on TEM design, based on principles from systems and control theory, is proposed here: measure-by-wire (not to be confused with remote microscopy). Under this perspective, the TEM operator yields the direct control of the microscope's internal processes to a hierarchy of feedback controllers and high-level supervisors. These make use of dynamical models of the main TEM components together with currently available measurement techniques to automate processes such as defocus correction or specimen displacement. Measure-by-wire is discussed in depth, and its methodology is illustrated through a detailed example: the design of a defocus regulator, a type of feedback controller that is akin to existing autofocus procedures.
authors.affiliation: Delft Center for Systems and Control, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands. a.tejadaruiz@tudelft.nl
authors.forename: Arturo
authors.initials: A
authors.lastname: Tejada
authors.forename: Arnold J
authors.initials: AJ
authors.lastname: den Dekker
authors.forename: Wouter
authors.initials: W
authors.lastname: Van den Broek
mesh_terms: D000465:Algorithms; D046529:Microscopy, Electron, Transmission / Q000295:instrumentation / Q000379:methods*