PERSONAL RADIATION MONITOR
A Personal Radiation Monitor instrument was developed that weighs 3 1/2 ounces and has the size of an ordinary fountain pen. Worn in the pocket of the user, the device provides immediate audible and visual indication of gamma dose rate. Indications are given by the simultaneous flash of a neon lamp and a burst of audible warning tone best described as a chirp. The repetition rate of the chirp and flash is proportional to gamma dose rate. The proportional range of indication extends from background to about 2 r/hr for instruments set to the normal range of sensitivity. An optional less sensitive range extends the upper limit of proportional indication to 200 r/hr. In either range the maximum indications do not block in overloading radiation fields short of that which would damage the components. To insure continious protection, there is no on-off switch. Operation for one month is obtained from a four volt mercury battery. The instrument uses a miniature halogen filled Geiger counter as the radiation detector. Generation of 500 volts to operate the counter is done by a transistor blocking oscillator, transformer, and semiconductor diode voltage quadrupler. Feedback through two transistor emitter followers increases the rate of the oscillator in proportion to Geiger tube current, and a fourth transistor amplities this tone into a hearing aid earphone with resonant air column. The electronic assembly is encapsulated in epoxy resin for protection and housed in a tubular stainless steel case fitted with a pocket clip. (auth)
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- NSA Number:
- NSA-15-032312
- OSTI ID:
- 4837956
- Report Number(s):
- ORNL-3058
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-61
- Country of Publication:
- United States
- Language:
- English
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