See the graphs on the trinity glass in J. Environmental Radioactivity
<a href="https://en.wikipedia.org/wiki/en:user:Cadmium" class="extiw" title="wikipedia:en:user:Cadmium">wikipedia:en:user:Cadmium</a>
<a href="https://en.wikipedia.org/wiki/Image:Bombvschernobyldoserateinopenair.jpg" class="extiw" title="w:Image:Bombvschernobyldoserateinopenair.jpg">w:Image:Bombvschernobyldoserateinopenair.jpg</a>