# dab

DAB (Debye Anderson Brumberger) Model

Parameter |
Description |
Units |
Default value |
---|---|---|---|

scale |
Scale factor or Volume fraction |
None |
1 |

background |
Source background |
cm |
0.001 |

cor_length |
correlation length |
Å |
50 |

The returned value is scaled to units of cm^{-1} sr^{-1}, absolute scale.

Calculates the scattering from a randomly distributed, two-phase system based on
the Debye-Anderson-Brumberger (DAB) model for such systems. The two-phase system
is characterized by a single length scale, the correlation length, which is a
measure of the average spacing between regions of phase 1 and phase 2. **The
model also assumes smooth interfaces between the phases** and hence exhibits
Porod behavior \((I \sim q^{-4})\) at large \(q\), \((qL \gg 1)\).

The DAB model is ostensibly a development of the earlier Debye-Bueche model.

**Definition**

where scale is

and the parameter \(L\) is the correlation length.

For 2D data the scattering intensity is calculated in the same way as 1D, where the \(q\) vector is defined as

**Source**

**References**

P Debye, H R Anderson, H Brumberger,

*Scattering by an Inhomogeneous Solid. II. The Correlation Function and its Application*,*J. Appl. Phys.*, 28(6) (1957) 679P Debye, A M Bueche,

*Scattering by an Inhomogeneous Solid*,*J. Appl. Phys.*, 20 (1949) 518

**Source**

**Authorship and Verification**

**Author:****Last Modified by:****Last Reviewed by:**Steve King & Peter Parker**Date:**September 09, 2013**Source added by :**Steve King**Date:**March 25, 2019