two hundred minute count on my rain sample as it hit 31 cpm Durham, NC Altitude 394 feet Geiger Counter Model 3007-A w/ External Pancake Beginning time 07/27/13 05:25:19 PM Ending time 07/27/13 08:49:43 PM Elapsed Minutes 204 Total Counts 40,971 Average CPM 200 Minimum CPM 31 Maximum CPM 647