Would someone please help me find a ZP1310 or ZP1410 Geiger-Muller tube for a geiger counter project I'm trying to build? I prefer the ZP1401 as this has an 'Alpha' window. I need location and price (in American dollars) of said parts. The article I'm building the curcuit from says that these are Philips parts, but Philips has no idea what I'm talking about or how to get them. Thanks lots.