The MAX IV accelerators are constructed with the goal of delivering the most intense and well defined beams of light possible to the experiment stations around the lab. There, researchers from all over the world use the light, predominantly in the ultraviolet and X-ray parts of the spectrum, for experiments on everything from new pharmaceuticals to materials for future electronics. At the same time, it is absolutely imperative that this is done in a way that is safe for those working in the lab.
The X-ray and ultraviolet light used for the experiments are different forms of electromagnetic radiation, just like visible light, but on the higher end of the spectrum. The process of accelerating and storing fast electrons at MAX IV gives rise to even higher energy radiation. This means that our radiation safety team have several radiation sources to take into account in their work. However, the radiation is only present when the accelerators are operating. When they are shut down the radiation immediately disappears.
The electromagnetic spectrum
The accelerators and experiment stations are encapsulated by radiation shielding to ensure that when they are in operation, no one is exposed to any harmful radiation. We also have a personnel safety system to make absolutely certain that no one can be present in these areas during operation. If someone would mistakenly try to enter, the doors are locked and if they would force the door open the power to the accelerators are immediately cut and the radiation is interrupted.
The radiation shielding for the accelerators are tunnels with 1.5 meter thick concrete walls. The experiment stations have shielding suited to the type of light being used at the particular station. For example, most experiment stations are enclosed by lead lined walls. The type and thickness of the shielding materials are carefully chosen after making detailed calculations and computer simulations, which are reported to and reviewed by the Swedish Radiation Safety Authority (SSM).
However, it is not enough just to trust the calculations and simulations. Each new experiment area and shielding wall is carefully monitored for possible radiation leaks with sensitive detectors. Even after we are satisfied with the shielding, while the facility is being used for scientific experiments, the radiation levels are continuously monitored. Should anything unusual be detected, the accelerators would be automatically shut down in less than a second.
Simulation and real experiment hutch at beamline MAXPEEM. The simulation shows the beam entering the hutch. The main lead wall and the hutch walls contain both the initial beam and the scattered beams.