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BS ISO 16700:2016 pdf free

BS ISO 16700:2016 pdf free.Microbeam analysis – Scanning electron microscopy – Guidelines for calibrating image magnification
Parameters that influence the resultant magnification of an SEM may cause systematic errors. These are listed in Annex B.
The stability of the SEM will be a major factor in determining the calibration interval. Initially, it will be necessary to perform calibration at frequent intervals in order to verify that the SEM is stable.
The results obtained will provide an estimate of the reproducibility within the laboratory and the bias inherent in both the display and the data automatically superimposed on any output.
The selection of the CRM depends on the magnification being used and accuracy required. For the purposes of this International Standard, ensure that the accuracy of calibration is better than 10 %.
Evacuate the specimen chamber to the working vacuum in accordance with the SEM manufacturer’s instructions.
Optimize the electron beam brightness and alignment in accordance with the SEM manufacturer’s instructions.
Set tilt angle to 0;, following the SEM manufacturer’s instructions so that CRM surface is perpendicular to the electron beam axis during operation.
Check the tilt of the CRM by the following procedures.
a) Turn off the tilt angle correction, the scan rotation and the zoom control of the magnification.
b) Select the imaging mode (secondary electron and/or back scattered electron).
c) Bring the image into focus without visible stigmatic distortions in the image.
d) Select the magnification at which the entire area of measurement is visible.
e) Determine the tilt position where the measured value of pitch is maximum. If the difference of measured values is not found, assume that the tilt angle is 0°. Carry out subsequent recording of the image in this position.
NOTE 1 If the image of the whole area cannot be brought into focus, then it is necessary to remount the CRM or readjust the mechanical alignment of the SEM.
f) Select the accelerating voltage and the working distance for which the calibration is to be performed and bring the CRM into the correct position using the specimen stage controls.
g) Wait until the instrument is fully stabilized at the desired operating conditions in accordance with the SEM manufacturer’s instructions.BS ISO 16700 pdf free download.

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