| 摘要 |
<p>1,255,221. Radiation detection. LA DETECTION ELECTRONIQUE FRANCAISE. Feb. 5, 1969 [Feb. 15, 1968], No. 6224/69. Heading G1A. Radiation incident on a tube detector 1 renders its conductive so that pulses from a generator 6 pass to a counter 10 which counter comprised three flip-flops 11-13 and which applies on signal to all the lines and to "AND" gate 19 when it is full, releasing relay 8 through a thyristor 21 to operate an alarm 23 and interrupting the pulse supply through contact 7. The alarm 23 indicates the presence of radiation which may be nuclear, or ultraviolet from a fire. The counter is reset by a second generator 18 having a different frequency. In a modification, Fig. 3 (not shown) a thyristor is activated by the output from a four stage counter. A system in which a number of alarm circuits are fed from a common pulse generator to operate a common alarm is also described. The pulse generators may comprise a rectifier bridge having a string of Zener diodes across and dipping its output.</p> |
