title: On the threshold conditions for electron beam damage of asbestos amosite fibers in the transmission electron microscope (TEM).
abstract: Asbestos amosite fibers were investigated to evaluate the damage caused by a transmission electron microscope (TEM) electron beam. Since elemental x-ray intensity ratios obtained by energy dispersive x-ray spectroscopy (EDS) are commonly used for asbestos identification, the impact of beam damage on these ratios was evaluated. It was determined that the magnesium/silicon ratio best represented the damage caused to the fiber. Various tests showed that most fibers have a current density threshold above which the chemical composition of the fiber is modified. The value of this threshold current density varied depending on the fiber, regardless of fiber diameter, and in some cases could not be determined. The existence of a threshold electron dose was also demonstrated. This value was dependent on the current density used and can be increased by providing a recovery period between exposures to the electron beam. This study also established that the electron beam current is directly related to the damage rate above a current density of 165 A/cm2. The large number of different results obtained suggest, that in order to ensure that the amosite fibers are not damaged, analysis should be conducted below a current density of 100 A/cm2.
authors.affiliation: a Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST) Montréal , Québec , Canada.|b Département de chimie , Université de Montréal , Montréal , Québec , Canada.|c Department of Mathematical and Industrial Engineering , École Polytechnique de Montréal , Montréal , Canada.
authors.forename: Joannie
authors.initials: J
authors.lastname: Martin
authors.affiliation: a Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST) Montréal , Québec , Canada.
authors.forename: Martin
authors.initials: M
authors.lastname: Beauparlant
authors.affiliation: b Département de chimie , Université de Montréal , Montréal , Québec , Canada.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Sauvé
authors.affiliation: c Department of Mathematical and Industrial Engineering , École Polytechnique de Montréal , Montréal , Canada.
authors.forename: Gilles
authors.initials: G
authors.lastname: L'Espérance
mesh_terms: D017639:Asbestos, Amosite / Q000737:chemistry* / Q000528:radiation effects*; D008274:Magnesium; D046529:Microscopy, Electron, Transmission / Q000379:methods*; D012825:Silicon / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission / Q000379:methods
chemical_list: D017639:Asbestos, Amosite; D008274:Magnesium; D012825:Silicon
keywords: Current density; damage mechanism; electron dose