I purchased a Cajoe V1 cheap 30 dollar geiger counter off ali express, had an RTC and a SD card reader from a random electronics kit, added a step down converter and an switch and SPI small screen to make this odd combo device, that takes current time and outputs the number of events (geiger counter outputs in interupt signals so i have it waiting one second and counting how many radiation detections go off), using that and math i found online i was able to put all the outputs and times into a csv file that can be pulled to see the data in excel.

using a 9v batt