Principles of Neutron Multiplicity
摘要
This chapter describes the extension of the neutron coincidence technique to the measurement of higher orders of correlation (beyond pairs). Successful use of this technique requires more efficient neutron detectors but allows measurement of items with more unknown properties (like impurities). The chapter includes a description of the electronics which is used as well as a mathematical description of the measured quantities and their relation to the properties of interest of the measured item. This is done for both passive methods (using the neutrons emitted from the item) as well as active methods (in which an external neutron source is used to induce fissions in the measured item). The chapter describes how the detectors are characterized and calibrated and presents areas of application and algorithm developments. The section on active counting describes the important concept of item coupling. The chapter concludes with a section on high accidentals multiplicity counting.