# power_law

Simple power law with a flat background

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

scale | Source intensity | None | 1 |

background | Source background | cm^{-1} |
0.001 |

power | Power law exponent | None | 4 |

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

This model calculates a simple power law with a flat background.

**Definition**

\[I(q) = \text{scale} \cdot q^{-\text{power}} + \text{background}\]

Note the minus sign in front of the exponent. The exponent *power*
should therefore be entered as a **positive** number for fitting.

Also note that unlike many other models, *scale* in this model
is NOT explicitly related to a volume fraction. Be careful if
combining this model with other models.

**References**

None.