Medical Linac

The Medical Linear Accelerator uses technology similar to that of the TRALAs main accelerator. For the MLA the primary electron beam is generated by an electron gun with an energy of about 50 keV. The electron gun, a diode design, has a pulse repetition frequency of 400 Hz. The electrons provided by the gun are accelerated by a copper S-Band structure in the range from 4 to 21 MeV with the same pulse repetition rate.

Even though the linac is designed to accelerate an electron to a maximum of 21 MeV, the energy can be increased by removing the power limit in the magnetron. The nominal power supplied by the magnetron is 2.5 MW at 4 MeV (low energies) and 5 MW at 25 MeV (high energies). As is usual, all steering and focusing of the beam is achieved by standard magnetic and electrostatic devices. After exiting the copper cavity, the beam is steered through 112.5 degree slalom-type magnetic and electrostatic devices before falling onto a high-Z element target. The target slows down the electron stopper and generates bremsstrahlung photons making the linac a source of photons. Naturally, the linac can also be used as and electrons source if the bremsstrahlung target is replaced with a thin foil.

Although MLA is designed for medical use, i.e. for patient treatment, it can also be used for research purposes, especially so if the machine is not used in conjunction with patient treatment. In such a case, the MLA effectively becomes a classical research linac. The applications as many ranging from fundamental research on photonuclear reactions and nuclei properties to applied nuclear physics research in the form of photoactivation analysis to applied radiation research like crosslinking, aging, induced mutations, food irradiation, etc.