Acer is a genus of trees or shrubs commonly known as maple. There are approximately 128 species, most of which are native to Asia, with a number also appearing in Europe, northern Africa, and North America. Only one species, Acer laurinum, extends to the Southern Hemisphere. The type species of the genus is the sycamore maple, Acer pseudoplatanus, the most common maple species in Europe.

The Multipurpose Applied Physics Lattice Experiment (MAPLE), later renamed MDS Medical Isotope Reactors (MMIR), was a dedicated isotope-production facility built by AECL and MDS Nordion. It was intended to include two identical reactors, as well as the isotope-processing facilities necessary to produce a large portion of the world's medical isotopes, especially molybdenum-99, medical cobalt-60, xenon-133, iodine-131 and iodine-125. An operational license for the MAPLE 1 reactor was granted in 1999, and the reactor went critical for the first time soon after. However, problems with the reactor, most notably a positive power co-efficient of reactivity, led to the cancellation of the project in 2008.