Defining a Receptor

Although you could compute impacts by simply using an Expression element, for convenience, the Contaminant Transport Module provides a specialized version of an Expression element called a Receptor to facilitate this calculation.

The dialog for a Receptor is shown below:

The dialog has three inputs:

Impact type: This is the type of impact to be computed. GoldSim provides three options:

• Risk (e.g., health or cancer risk);

• Dose (radioactive dose); and

• Hazard Index.

The choice of the Impact type determines the dimensions of the Receptor output (and therefore the dimensions of the vector accepted by the Impact input field):

• A Risk has dimensions of inverse time (e.g., the incremental cancer risk per individual per year);

• A Dose has dimensions of radiation dose per time (e.g., mrem/yr, Sv/yr);

• A Hazard Index is dimensionless and is intended to represent a ratio of concentrations (the concentration in a medium divided by some reference concentration).

Impact: This is the equation describing the impact itself. It must be a vector by species. Its dimensions are determined by the impact type.

For Risk and Dose impacts, it will typically be specified as a sum of several term-by-term vector multiplications (a concentration vector multiplied by an impact conversion factor vector).

For a Hazard Index impact, it will typically be specified as a sum of several term-by-term vector divisions (a ratio of concentrations).

The multiplication (*) and division (/) operators can be used to carry out a term-by-term multiplication or division of two vectors.

Display Units: This is the units in which the output of the Receptor is displayed. The acceptable dimensions are determined by the Impact Type (inverse time for Risk, dose/time for Dose, dimensionless for Hazard Index).