English to Italian Social Sciences Government / Politics Prison policies

It is a special unit inside some American prisons, where inmates are kept for some time due to their negative behaviour (such as violating some inner regulations, beating other inmates, and so on...) but it is NOT isolation, since they are always two in each cell, they can even go out in a special fields as workers. Can you help me with the closest Italian translation as possible, even if there is no such unit in Italian prisons? Thank you very much. P.S.: it is for a documentary Tv series on American prisons.