What sub-syndrome is normally seen at the lower range of exposure of acute radiation syndrome?

At the lower range of exposure in acute radiation syndrome, the sub-syndrome typically observed is the hematopoietic syndrome. This syndrome primarily affects the bone marrow, leading to a decrease in blood cell production, which can result in symptoms like anemia, increased susceptibility to infections, and bleeding disorders. The severity of symptoms depends on the dose of radiation received, with higher doses leading to more severe manifestations.