RSoXS Scattering Calculator
Assumptions used in defaults:
- Detector size: 61.7 mm (width) x 61.4 mm (height)
- Default sample-to-detector distance: 30 mm
- Beam energy defaults to 291.65 eV (carbon edge calibration point)
- Top-down coordinates: beam is left to right (+z), outboard is +x (top of sketch), inboard is -x (bottom of sketch)
- Detector translation path is approximated as 45 degrees inboard and downstream, with detector center crossing the beam axis near z = 30 mm
- Travel window defaults to z = 10 mm to 120 mm
The calculator fills inferred values, highlights them, prints a detailed summary, and updates a top-down geometry sketch.
How This Calculator Works (Equations + Geometry)
The calculator below uses the following equations.
Energy to wavelength: \[\lambda = \frac{hc}{E} = \frac{1239.841984\,\mathrm{eV\cdot nm}}{E\,(\mathrm{eV})}\]
Real-space to scattering vector: \[q\,(\mathrm{nm}^{-1}) = \frac{2\pi}{d\,(\mathrm{nm})}\]
Scattering vector from angle: \[q = \frac{4\pi}{\lambda}\sin\theta\] where \(\theta\) is half of the total scattering angle \(2\theta\).
Detector-angle relation for a radius \(r\) at sample-to-detector distance \(z\): \[2\theta = \arctan\left(\frac{r}{z}\right)\]
Inverse relation used to place a target \(q\) on the detector: \[r = z\tan\left(2\arcsin\left(\frac{q\lambda}{4\pi}\right)\right)\]
In this page, the detector center shifts with distance using the same 45 degree inboard/downstream approximation used elsewhere in this wiki. The beamstop sets the lowest measurable radius around the direct beam, and detector edges set the highest measurable radius.
RSoXS Detector Coverage Calculator (Unified Inputs)
Enter what you know and leave unknown fields blank. Click Calculate; inferred fields are highlighted.
Beamline and Detector Inputs
Problem Inputs (leave unknown blank)
Top-Down Sketch (Detector 1)
Solid red line is the incoming beam. Dashed red lines are scattered x-rays for the entered size scale d. Inboard is downward (-x).