Geiger counters are devices used to measure the amount of radiation in the environment. Geiger counters are used as ghost hunting tools because it is theorized that disturbances in radiation levels of alpha, beta, gamma, or even x-rays, might be indicators of the presence of a ghost or other spirit. They have been used by a number of ghost hunters as investigation tools for a few decades now.
Geiger counters detect ionizing radiation through a gas-filled tube which conducts electricity when a particle of radiation suddenly makes the gas in the tube conductive. This conductivity is then amplified and then displayed either using a needle to measure the radiation level or with a series of auditory clicks indicating how much or how little radiation might be in the environment.
As with most other tools available to paranormal researchers, the geiger counter will only indicate that radioactive ions are present and how much is there. This could be due to a number of environmentally explainable reasons as well. For instance, radon or other naturally occurring radioactive elements may already be present in the environment. It is best for investigators using geiger counters and other measurement tools to use critical thinking and additional research methods in an attempt to consider all possible explanations for a given measurement rather than automatically attributing it to a ghost or spirit simply because the origin is unknown.
Ghost Hunting Store - Geiger Counters
Geiger counters are relatively cheap and come in compact, hand-held form. TheGhostHunterStore.com offers a very cost effective series of geiger counters.