Dear Tarsonis, thank you for your interest. The small pin-diode based detector was used mostly for illustrative putposes and that the students could experiment with a detector that resembles the HPGe detector, which was used to analyse the dried mushrooms the pupils sent back to us.  Some of the results are available in the nucelar physics news link http://doi.org/10.1080/10619127.2019.1603559 which is already given in another comment and there is a conference report forthcoming.  

Sur la newsletter française, Elektor parle de grillons. Or ce sont des photos de criquets… C'est pas la même chose.

Hello, maybe I've misread the links, but I can't find measurement you got from project with PIN diode. As the Bq/kg I've found are about hundreds or thousands, I guess they are not from the small PIN diode that is giving to me ~ 1CPM in best cases. I've tried on swedish webiste (massexperiment) but keywords as CS137 are not giving results. Would it be possible to get a direct link to those measurements ? Thanks !

Antenne dièdre pour routeur ou ploint d'accès WiFi dans la bande des 2,4 GHz.

Oh no! I just realized there is already a similar project on labs. Only bigger, better and in color ... silly me... https://www.elektormagazine.de/labs/rgbdigit-clock-160100-1