RONCHIGRAM.COM

Training Mode

Schnitzer, N., Sung, S. H., & Hovden, R. (2019). Introduction to the Ronchigram and its Calculation with Ronchigram.com. Microscopy Today, 27 (3).
Schnitzer, N., Sung, S. H., & Hovden, R. (2020). Optimal STEM Convergence Angle Selection Using a Convolutional Neural Network and the Strehl Ratio. Microsc. Microanal. 26 (5).

Ronchigram

π/4 Phase Limit

Electron Probe

e- Beam Energy = keV ⇒ Wavelength = pm

○ Objective Aperture Semiangle = mrad

Diffraction Limited Resolution = pm

○ π/4 Aperture Semiangle = mrad

Strehl Ratio for π/4 Semiangle =

○ Aperture Semiangle for Strehl Ratio of 0.8 (optimal) = mrad

Show image overlays
χ(α,Φ) = Σn,m[ Cn,m α n+1cos(m(Φ-Φn,m))/(n+1) ]
Aberration

Symbol

(Haider)

Symbol

(Krivanek)

Defocus
C1
C10: Å
2-Fold Astigmatism
A1
C12: nm     Φ 12: °
Axial Coma
B2
C21: nm     Φ 21: °
3-Fold Astigmatism
A2
C23: nm     Φ 23: °
3rd Order Spherical
C3
C30: nm    
3rd Order Axial Star
S3
C32: nm     Φ 32: °
4-Fold Astigmatism
A3
C34: nm     Φ 34: °
4th Order Axial Coma
B4
C41: μm     Φ 41: °
3-Lobe Aberration
D4
C43: μm     Φ 43: °
5-fold Astigmatism
A4
C45: μm     Φ 45: °
5th Order Spherical
C5
C50: mm    
5th Order Axial Star
S5
C52: mm     Φ 52: °
5th Order Rosette
R5
C54: mm     Φ 54: °
6-fold Astigmatism
A5
C56: mm     Φ 56: °
Chromatic Aberration
Cc
Cc: 0 m

Display Size (pixels)= Display Size (mrad) =

Sample Scale (Factor of Display Size (px)) =

Force Javascript instead of WebAssembly (Slow, run at 256 px, ~10s)

Map Keys to Defocus (Up, Down), 2-fold (wasd), Coma (ijkl) (Dev)

Use Coefficients from a Real Microscope (instead of randomly generated sets)

Calculate Strehl Aperture Semi-Angle (slow)

By Suk Hyun Sung, Noah Schnitzer & Will Millsaps @ Hovden lab

Version 2.0, Check out the source on GitHub