Receptors have a single output, the resulting impact vector. It is a vector by species, and its dimensions are defined by the impact type.
You specify that you wish to save these results by clicking Final Values and/or Time History at the bottom of the Receptor editing dialog:
If you are running multiple realizations, the Time History box is ignored, and unless an output of the element is connected to a Time History Result element, no time history results will be saved at all for the element. In fact, in such a case, the Save Results section (for items 1 and 3 above) would look like this:
In this particular case, because the simulation involves multiple realizations, the “Time History” checkbox is replaced by a “Monte Carlo Histories” checkbox. This checkbox is grayed out, since it is only used for information purposes. You cannot edit it directly, and its appearance is completely determined by whether or not the output is connected to a Time History Result element. That is, in order to save time history results for a Receptor when running multiple realizations, you must connect it to a Time History Result element.