I agree. It seems that a simple gamma ray direction finder mounted to a low flying aircraft should have been sufficient assuming that the background radiation

I agree. It seems that a simple gamma ray direction finder mounted to a low flying aircraft should have been sufficient assuming that the background radiation was not a concern. They could have triangulated/geolocated to a small area very quickly. https://www.researchgate.net/publication/7009180_A_simple_gamma_ray_direction_finder https://www.researchgate.net/publication/7009180_A_simple_ga...