LBP2 User Guide
Document No: 50306-001
Rev G 3/12/2020
Page 79
The Diameter percent of total is derived by taking the area of all pixels above the
clip level, and computing the diameter of a circle that contains that amount of
area. The default clip level is 86.5% which will yield an accurate second moment
beam width for a TEM
00
beam.
When rotated beam results are disabled, the computed beam widths are the
measure of the pixels in the row and column that pass through the centroid. The
beam widths in the results window are labeled X and Y.
When rotated beam results are enabled, the computed beam widths are the
measure of the pixels along the Major and Minor axes that pass through the
centroid. The beam widths in the results window are labeled M/Major and
m/minor.
5.9.4
Percent of Peak Method
D%pkX/M, D%pkY/m, D%pk
LBP2 analyzes two orthogonal lines of pixels that pass through the beam centroid.
The beam widths are determined by separately looking out along each line and
counting all the pixels that are greater than the set clip level. The reported beam
widths are the number of pixels greater than the clip level multiplied by the pixel
pitch or the pixel pitch adjusted by the orientation angle.
The default clip level is 13.5% which will yield an accurate second moment beam
width for a TEM
00
beam.
The Diameter percent of total is derived by taking the area of all pixels above the
clip level, and computing the diameter of a circle that contains that amount of
area. The above clip level is also applied and if set to 13.5% will yield an accurate
second moment beam width for a TEM
00
beam.
When rotated beam results are disabled, the computed beam widths are the
measure of the pixels in the row and column that pass through the centroid. The
beam widths in the results window are labeled X and Y.
When rotated beam results are enabled, the computed beam widths are the
measure of the pixels along the Major and Minor axes that pass through the
centroid. The beam widths in the results window are labeled M/Major and
m/Minor.
5.9.5
Moving Slit Percent of Peak Method
D%msX/M, D%msY/m
LBP2 emulates a moving slit by summing the rows and columns of data in either
the X/Y or the M/m axial directions. The beam widths are determined by
separately looking out along each line and counting all the sums that are greater
than the set clip level of the peak sum. The reported beam widths are the number
of sums greater than the clip level multiplied by the pixel pitch or the pixel pitch
