It's an Am-Be source used for well logging. The Am-241 emits an alpha particle which strikes the Be-9 leading to C-6 and a neutron. Neutron energies typically range from 2-10 MeV, averaging around 4.5 MeV. You get about 35 mrem/hr per Ci of Am-241 at 30 cm, and these devices typically have something like 10 Ci, so expect around 350 mrem/hr at 30 cm.
The news article totally misses the neutron component which is the primary reason the search is on. Any alpha radiation is stopped by the metal casing, and the gamma radiation is a factor of 100 or so less than the neutron radiation.