ANTARCTIC DOSIMETRY A PRELIMINARY STUDY OF BACKGROUND RADIATION LEVELS AT HIGH LATITUDES

A significant proportion (13%) of the natural background radiation is of cosmic origin. Charged particles (e.g. from the Sun), such as protons, interact with the magnetic field of the Earth and can be deflected by it. This effect is reduced at the magnetic poles. Still, particles that enter the Earth’s atmosphere commonly do not reach its surface, as they are slowed down by scattering and collisions. Therefore, most of their energy reaches the Earth’s surface in the form secondary particles and photons (e.g. X-rays). As charged particles are less deflected at the magnetic poles, an increase of ionising radiation dose similar to what has been reported in aircrew, is expected at high (magnetic) latitudes. Similarly, it is well known that UV radiation levels are raised in Antarctica, where the atmosphere has been compromised. Measurements of UV and X-ray radiation levels were conducted in Antarctica in December and January 2006/2007, in order to investigate the relative intensities of both ionising and non-ionising radiation in the South Polar Region compared to Christchurch, New Zealand. While increased levels of UVA and UVB radiation were measured, the TLD dosimeters used for X-ray measurements were found t