Fissionsbarriärer

Fissionsbarriärer, known in English as fission barriers, represent a fundamental concept in nuclear physics related to the stability of atomic nuclei. A fission barrier is the energy a nucleus must overcome to undergo nuclear fission, the process where a heavy nucleus splits into two or more lighter nuclei, along with neutrons and energy. This barrier arises from the interplay between the attractive nuclear force, which holds the nucleus together, and the repulsive electrostatic force between the positively charged protons.

When a nucleus absorbs energy, for example, through the capture of a neutron, it can become excited. If this excitation energy is sufficient to overcome the fission barrier, the nucleus will deform. As the deformation increases, the repulsive forces begin to dominate, stretching the nucleus until it eventually elongates and splits. The height of the fission barrier is a critical factor determining the probability of fission. Nuclei with higher fission barriers are generally more stable and less likely to undergo spontaneous fission.

The concept of the fission barrier is crucial for understanding nuclear chain reactions, the design of nuclear reactors, and the processes occurring in stars. Theoretical models, such as the liquid drop model and the shell model, are used to predict and understand the magnitude of fission barriers for different isotopes. Experimental measurements of fission cross-sections and half-lives provide empirical data that helps refine these theoretical predictions.