A radiation detection apparatus having a hand-held radiation detection probe with a switch assembly removably mounted thereon is hereinafter disclosed. The switch assembly having first and second switches, one to initiate transmission of electrical signals representing scintillations detected over a set time period to a remotely located control unit for counting and averaging, and the other to direct the control unit to download and preferably record the counted and averaged scintillation values for further use. The switch assembly has an insulating member for electrically insulating the switches from the probe, and spaced gripping members that releasably grip the probe. A movable stand is provided preferably with a holder for holding the probe. The probe can have a protective cover thereon with a switch assembly mounted onto the probe over the cover.