Neutron dose near the AOS and the OSF was measured with a Fuji Electric NSN10014 neutron dosimeter.
The detector of NSN10014 is a spherical 3He proportional counter covered in spherical polyethylene and having a neutron energy range from 0.025 eV to 8 MeV with an energy response in accordance with ICRP 51 standard.
Measured neutron dose rates were 0.80 mSv yr-1 at Pampa La Bola, and 0.25 mSv yr-1 at San Pedro de Atacama, respectively, whereas it was 0.01 mSv yr-1 at Santiago.
These values are even higher than world average dose rates at comparable altitudes, probably reflecting enhancement of incoming primary cosmic rays near the South Atlantic Anomaly.
- Sakamoto, S., Iguchi, S., Wajima, K., Koshiishi, H., Goka, T., Matsumoto, H., & Kitamura, H. 2003, "Levels of radiation exposure near AOS and OSF," ALMA Memo 446