  Double beta decay is a very rare nuclear process and, therefore, experiments
intended to detect it must be operated deep underground and in ultra-low
background conditions. Long-lived radioisotopes produced by the previous
exposure of materials to cosmic rays on the Earth's surface or even underground
can become problematic for the required sensitivity. Here, the studies
developed to quantify and reduce the activation yields in detectors and
materials used in the set-up of these experiments will be reviewed, considering
target materials like germanium, tellurium and xenon together with other ones
commonly used like copper, lead, stainless steel or argon. Calculations
following very different approaches and measurements from irradiation
experiments using beams or directly cosmic rays will be considered for relevant
radioisotopes. The effect of cosmogenic activation in present and future double
beta decay projects based on different types of detectors will be analyzed too.
