Radiation protection

Radiation protection forms the basis for any nuclear technology. Our knowledge and expertise in this field provides you a safe device, reliable long-term cost calculations, and an easy integration of our products into existing structures.

Radiation protection intends to avoid any dangers for the general public from the exploitation of nuclear technology. As such it defines so called protection quantities, namely the radiation dose unit Sievert (Sv). The natural dose rate is in the order of 0.1 µSv/h, while technical exposures up to about 10 times of the natural level are allowed per year under certain conditions (depending on national regulations). IBA easily achieves dose rates >1 mSv/h for highly productive analysis. Legislation sets the rules for technical and organisational means to reduce radiation doses to public and staff. Four A's and the ALARA principle give the basic advice of how to achieve this. Technical means are always the preferred option for achieving low doses from both safety and economy perspectives.

Our setups implement a combination of optimised detection and analysis layouts for reducing the primary emitted dose, radiation shielding, and remote control. For ion beam analysis shielding represents a special challenge, since it mostly emits MeV neutrons due to nuclear reactions. Due to the low reaction cross-sections of neutrons at MeV energies, neutron shielding requires a combination of energy reducing isotopes, in particular hydrogen, and isotopes with neutron capture reactions in the shielding material. Special plastics provide tenth-value attenuation length in the order of 100 mm. For bringing down the mSv levels of primary radiation to <µSv levels this would require >400 mm of shielding thickness, too much for practical devices. The primary dose rates of photon radiation are typically >100 times lower compared to the neutron dose rates, making additional photon specific shielding irrelevant.

Consequently, we follow a combined approach of shielding and reduced primary dose rates by optimising the following three aspects simultaneously. Applying larger detectors requires lower beam current to achieve the same signal intensity, but increases device costs and reduces energy resolution. The projectile energy determines the reactions available for analysis and their cross-section, but the emitted radiation dose rates monotonically increase with beam energy. The emitted dose rates and the signal intensities are both directly proportional to the ion beam current. This directly connects a fast and productive analysis to high radiation dose rates. Our combined understanding of radiation protection, ion-matter interactions, detector technology, and engineering provides our customers unique solutions with an unprecedented degree of optimisation in this complex technological optimisation space.

Aachen Ion Beam Technology
MeV ion beam analysis by RBS, NRA, PIXE, and PIGE