ASTM E766-14(R2019) pdf free download
ASTM E766-14(R2019) pdf free download.Standard Practice for Calibrating the Magnification of a Scanning Electron Microscope
1. Scope
1.1 This practice covers general procedures necessary for the calibration of magnification of scanning electron micro- scopes. The relationship between true magnification and indi- cated magnification is a complicated function of operating conditions. 2 Therefore, this practice must be applied to each set of standard operating conditions to be used. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions: 3.1.1 For definitions of metallographic terms used in this practice see Terminology E7. 3.1.2 The definitions related to statistical analysis of date appearing in Practice E177, Terminology E456, and Practice E691 shall be considered as appropriate to the terms used in this practice. 3.2 Definitions ofTerms Specific to This Standard: 3.2.1 calibration—the set of operations which establish, under specified conditions, the relationship between magnifi- cation values indicated by the SEM and the corresponding magnification values determined by examination ofa reference material. 3.2.2 calibration method—a technical procedure for per- forming a calibration. 3.2.3 certified reference material—reference material, ac- companied by a certificate, one or more of whose property values are certified by a procedure which establishes its traceability to an accurate realization of the unit in which the property values are expressed, and for which each certified value is accompanied by an uncertainty at a stated level of confidence (see ISO Guide 30:1992). 3.2.4 pitch—the separation of two similar structures, mea- sured as the center to center or edge to edge distance. 3.2.5 reference material—a material or substance one or more of whose property values are sufficiently homogeneous, stable, and well established to be used for the calibration of an apparatus, the assessment of a measurement method, or for assigning values to materials (see ISO Guide 30:1992). 3.2.6 reference standard—a reference material, generally of the highest metrological quality available, from which mea- surements are derived.
4. Significance and Use
4.1 Proper use of this practice can yield calibrated magni- fications with precision of 5 % or better within a magnification range of from 10 to 50 000X. 4.2 The use of calibration specimens traceable to international/national standards, such as NIST-SRM 484, with this practice will yield magnifications accurate to better than 5 % over the calibrated range of operating conditions. 4.3 The accuracy ofthe calibrated magnifications, or dimen- sional measurements, will be poorer than the accuracy of the calibration specimen used with this practice. 4.4 For accuracy approaching that of the calibration speci- men this practice must be applied with the identical operating conditions (accelerating voltage, working distance and magni- fication) used to image the specimens of interest. 4.5 It is incumbent upon each facility using this practice to define the standard range of magnification and operating conditions as well as the desired accuracy for which this practice will be applied. The standard operating conditions must include those parameters which the operator can control including: accelerating voltage, working distance, magnification, and imaging mode.
