ALMA-J Site Testing
ALMA-J Site Testing Archive
Last update 2005-02-07

Neutron Dosimeter

    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.


Technical Description