Yes, and yes. Since the internal biological clock, which lies at the base of the brain, is a nucleus of oscillation neurons, it is possible that radiation altered its timing properties irreversibly. That does not mean your extreme morningness is irreversible, however. You could try light therapy — for starters, around 7 p.m., when the evening slump sets in. You may find that it gives a significant boost, which could allow you to resume a later, “normal” bedtime.