BUILD AN EMERGENCY RADIATION MONITOR ALARM BEEP BEEP

摘要

When I wrote the article on a recording radiation counter back in the March 2013 issue, I had planned to follow up right away with an inexpensive version of a radiation monitor. I even had circuit boards made. However, upon testing, I found it did not work. For two months averaging four hours a day, I toiled away, trying to get it to perform correctly but only came away frustrated. I tried circuit after circuit, including one that was for sale by a local kit maker. My wife calls me stubborn, but I prefer the word tenacious. I breadboarded schematic after schematic, and put in SPICE models with no success. Several types of pin diodes were tried and tossed. My main problem was getting a gamma source for testing. Lantern mantles emit mostly alpha and beta rays with a few gammas. I finally managed through some college connections to obtain both a Cesium and a Cobalt source. In retrospect, it was the breadboarding and the absolute necessity of having the unit shielded which affected my progress.