Cylinder

An upright circular cylinder.

Constructor

Cylinder(R, H)

Parameters:

  • R, radius
  • H, height

Usage

As for any other Form factor.

Implementation

Class Cylinder inherits from the interface class IFormfactor .

Form factor is computed as

$$ F(\mathbf{q})=2\pi R^2H \space \exp\Big(iq_z\dfrac{H}{2}\Big) \text{sinc}\Big(q_z\dfrac{H}{2}\Big) \dfrac{J_1(q_{\parallel}R)}{q_{\parallel}R} , $$ with the notation $$ q_{||} := \sqrt{q_x^2 + q_y^2}. $$

Volume has been validated against $$V=\pi R^2H.$$

More general:

Example

Scattering by uncorrelated, oriented cylinders for horizontal incidence. Rotation around $y$ axis:

Generated by Examples/ff/Cylinder.py .

History

This form factor is well known; it goes back to Lord Rayleigh.

In IsGISAXS and FitGISAXS, it has been implemented as form factor “Cylinder” [manual, Eq. 2.26; Renaud 2009, Eq. 223; Babonneau 2013].