MightyOhm.com

Jeff,

What does it take to make a Geiger counter detect alpha radiation and can your kit be adapted to detect all types of radiation: alpha, beta and gamma?

Thank you

To detect alpha radiation, you will need a geiger tube that is sensitive to alpha. The LND-712 is a common alpha/beta/gamma tube in the United States, and I see Sparkfun is selling them again:
http://www.sparkfun.com/products/8875

There are other tubes that will work (I think the SBT-9 is the most common Soviet tube).

The important thing for the kit is that the tube must have an operating voltage between 350-600V.