Beam footprint (Bragg-Brentano geometry)
About the calculator
The calculator calculates the width of the incident X-ray beam on a sample for a given incident angle (θ), divergent slit size (R), and the goniometer radius (D).
How to use it
- Set the starting incident angle (θstart) and the step angle (θstep) to run the calculation.
- Enter the goniometer radius (D).
- Enter the divergent slit size (R) to calculate the beam footprint for different incident angles. You can set up to four slit widths.
Theory
Variables
| Symbol | Meaning | Units |
|---|---|---|
| θstart | Starting incident angle | degree |
| θstep | Incident angle step size | degree |
| R1 – R4 | Divergent slit size(s) | degree |
| D | Goniometer radius | mm |
The beam footprint F at incident angle θ is calculated as:
\(F = \left(\frac{D}{\sin(\theta+R)} + \frac{D}{\sin(\theta-R)}\right)\cdot \sin(R)\)
Incident angle parameters
[deg]
[deg]
Goniometer parameter
[mm]
Divergence Slit Sizes
R = [deg]
[deg]
[deg]
[deg]
[deg]
Beam Width vs Incident Angle
Beam Width Results
| 2θ [deg] | F1 [mm] | F2 [mm] | F3 [mm] | F4 [mm] |
|---|