基本信息
摘要：1,102,582. Detecting neutrons. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. 15 July, 1965 [22 July, 1964]. No. 29635/64. Heading G6P. In a nuclear reactor period meter, a neutronsensitive ionization chamber supplies a tuned circuit the output from which is applied to a logarithmic A.C. amplifier which in turn feeds a linear rectifier. The output from the latter supplies a neutron flux level meter and, in parallel, a D.C. amplifier and differentiator which provide a signal representing the reciprocal of the reactor period. The tuned circuit comprises a resonant series LC circuit of high-Q value. The logarithmic amplifier includes both D.C. feedback to stabilize against temperature variations of the parameters and A.C. feedback through semi-conductor diodes to provide the logarithmic characteristic. Phase correcting networks are inserted to prevent instability in the feedback loop caused by integrating effects. The linear rectifier comprises an A.C.-coupled saturating amplifier associated with an earthedcollector chopper transistor, driven in synchronism with the input waveform. In an alternative arrangement, a D.C. logarithmic amplifier is employed.
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