Geiger module power and current consumption?

Hi there, 

For some art project, I'd need about 8 geiger counters connected ideally on the same device (arduino or raspberry) 

Can you tell me the power required per geiger counter module? 

I'd need to calculate if I need an external power device or not

BTW, the first module I have is pulsating across the web and pulses are visible there : https://structure-void.com/rnbo_examples/geiger_flash_ping

Best regards,