Geiger counter

Hello
I'm looking for a geiger counter for a student project, for sale or buildable in Europe/Denmark.

Specifications: lightweight, readout counts by arduino, should be able to run on battery, sensitive.

Alternative just the geiger tube.

Anyone who could recommend this sort of equipment?
Best, Jon

Google "diy geiger counter" for several leads. Ebay has tubes and a number of driver boards.

Atmega328P