Gains Tutorial Andy Therrien

Uncorrected Image Ni/Cu alloy CO dose and 120 K anneal Atomic Resolution 80 K Image

Uncorrected Image 5 Deg off horizontal Measure across 39 Cu atoms X Component: Cos(5) = X/H Actual: H = 9.6509 nm X = 9.614 nm Theoretical: H = 0.256 x 39 = 9.984 nm X = 9.946 X Correction: 9.946/9.614 = 1.035 Adjacent = X Hypotenuse

Uncorrected Image 0.5 Deg off vertical (more evidence that there is an angle error in raw image) Measure across 31 root 3 Cu spacings Y Correction: Cos(0.5) = A/H Actual: A = 9.6395 nm H = 9.639 nm Theoretical: A = (√3)0.256 x 31 = 13.746 nm H = 13.745 13.745/9.639 = 1.426 Hypotenuse Adjacent = Y

Apply the Gains Measure over 10 atoms in each close packed direction (so each should be 2.56 nm) 2.5896 nm (1.2% error) 2.4173 nm (5.6% error) 2.7272 nm (6.5% error) The one we calibrated for is really good but the other two are off

Unit Cell Detection Software tells you what to do In dialog box select oblique Set your angle to 60 (or 120 depending of unit cell) Set La and Lb to whatever you made your unit cell (so this is 7 by 8 atoms so its 1.792 by 2.048) Hit apply and make sure the correction factors at the bottom are reasonable

Apply the Gains Measure over 10 atoms in each close packed direction 2.6016 nm (1.6% error) 2.5194 nm (1.6 % error) 2.5350 nm (1.0% error) All of them are pretty good, if you want to improve more do it again!