There are a lot of publications on the Internet on how to convert CPM (Counts per Minute) obtained from a Geiger tube to radiation levels. 

However, despite the wide coverage of this topic on various forums and a wide range of examples with code for various programming languages, we had to understand the topic deeper than we wanted to in order to be able to properly calculate the conversion factor for Geiger tube SBM20 from CPM to absorbed dose of radiation μSv/h and configure the conversion in our own products and make an example calculation for everyone.

Read the full story here:

https://iot-devices.com.ua/en/technical-note-how-to-calculate-the-conversion-factor-for-geiger-tube-sbm20/