title: Specimen Behavior in the Electron Beam.
abstract: It has long been known that cryo-EM specimens are severely damaged by a level of electron exposure that is much lower than what is needed to obtain high-resolution images from single macromolecules. Perhaps less well appreciated in the cryo-EM literature, the vitreous ice in which samples are suspended is equally sensitivity to radiation damage. This chapter provides a review of several fundamental topics such as inelastic scattering of electrons, radiation chemistry, and radiation biology, which-together-can help one to understand why radiation damage occurs so "easily." This chapter also addresses the issue of beam-induced motion that occurs at even lower levels of electron exposure. While specimen charging may be a contributor to this motion, it is argued that both radiation-induced relief of preexisting stress and damage-induced generation of additional stress may be the dominant causes of radiation-induced movement.
authors: Lawrence Berkeley National Laboratory, University of California, Berkeley, CA, United States. Electronic address: rmglaeser@lbl.gov.
authors: R M
authors: RM
authors: Glaeser
mesh_terms: D016477:Artifacts; D020285:Cryoelectron Microscopy / Q000295:instrumentation / Q000379:methods*; D004307:Dose-Response Relationship, Radiation; D004583:Electrons; D007053:Ice; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D009038:Motion; D011506:Proteins / Q000528:radiation effects* / Q000648:ultrastructure; D055672:Static Electricity; D013314:Stress, Mechanical; D013816:Thermodynamics; D058989:Vitrification / Q000528:radiation effects*
chemical_list: D007053:Ice; D011506:Proteins
keywords: Energy deposited; Radiation dose; Specimen charging; Specimen damage; Specimen motion