Effective radius correction coefficient

[paulmueller]

If the indented object is spherical, there is a correction factor that can be applied to the radius.

• collect literature
• find a user-friendly way (that is not confusing) to implement a helper function
• make sure this works with data export

[Shadahattum]

Literature I have relied on to calculate the correction factor :

https://pubs.rsc.org/en/content/articlelanding/2014/sm/c4sm00788c/unauth

equation 12 shows how the correction factor is calculated from the radii of the indenter, indented object and substrate.

example:

Indenter R1 = 2.5 µm
Cell R2 = 7.5 µm
Surface R3 = ∞

1/R12 = 1/R1+1/R2
1/R32 = 1/R2 + 1/R3 = 1/R2

K= R2^(1/3)/(R2^(1/3)+R12^(1/3))=0.613

K is the correction factor that is multiplied by the indentation signal

[paulmueller]

This is implemented in nanite 3.5.0: AFM-analysis/nanite@45bf36a