and then the user measures the rate in which the leaves close. How it works An electrostatic charge is placed upon two aluminium foil leaves, causing them to repel. As radiation strikes the meter, the foil leaves lose their charge and start to droop. This droop can be measured, and its rate can be established. The KFM has been used as a science project, demonstrating the effects of ionizing radiation. The dimensions of a KFM and the weight of its leaves permanently establish its calibration, when built as specified with a properly sized scale. See also Geiger counter Kearny air pump Civil defense by country References External links Plans Nuclear War Survival Skills Appendix C by Cresson Kearny Full Report: The KFM, A Homemade Yet Accurate and Dependable Fallout Meter Online version of the plans in Nuclear War Survival Skills PDF version of the plans Nuclear War Survival Skills Google Books Oregon Institute of Science and Medicine Cold War Nuclear warfare Civil defense Disaster preparedness Improvisation Ionising radiation detectors 1978 introductions 1978 in science Science and technology in the United States