ASTM E766-14e1

4.1 Proper use of this practice can yield calibrated magnifications 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 of the calibrated magnifications, or dimensional measurements, will be poorer than the accuracy of the calibration specimen used with this practice.

4.4 For accuracy approaching that of the calibration specimen this practice must be applied with the identical operating conditions (accelerating voltage, working distance and magnification) 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.

1.1 This practice covers general procedures necessary for the calibration of magnification of scanning electron microscopes. The relationship between true magnification and indicated 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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.