ABSTRACT
Q-values of nuclear decays and reactions are differences of atomic masses in the initial and final states. In some cases such Q-values are related to fundamental questions in current physics requiring an extremely high mass accuracy, which can only be reached with Penning traps. Hans Dehmelt, one of the Nobel laureates in Physics 1989, introduced the name Penning trap. The reason was that the trap he used when measuring g-2 of the free electron [1] with such a formidable accuracy (g= 2 + 2 x 10_12x 1 159 652 188.4) was rather similar to a vacuum gauge invented by F. M. Penning [2] who at that time employed by Philips.
