1. Gains Tutorial
Andy Therrien

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

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

4. 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 = nm
H = nm
Theoretical:
A = (√3)0.256 x 31
= nm
H =
13.745/9.639 = 1.426
Hypotenuse
Adjacent = Y

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

7. 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 by 2.048)
Hit apply and make sure the correction factors at the bottom are reasonable

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