Fast, versatile modules increasing the conversion gain of multichannel analyzers in multiparameter measurements

The design of a fast, versatile associative module (AM) increasing the conversion gain of multichannel analyzers (MA) in multiparameter measurements is reported. The design is especially suitable for pulse height spectrum measurements from high counting rate sources as would be found in reactor sample on-line monitoring systems, being able to acquire spectrum data at input rates in excess of 10⁵ Hz. Specific characteristics of the instrumentation are as follows: 1) the system´s basic structure is implemented by one multichannel analyzer and one associative module, and allows a programmable conversion gain. The maximum achievable conversion gain is 2⁶⁰. If the MA dead time is shorter than the AM dead time, the dead time of the system is equal to 340 ns. 2) The basic structure can be expanded vertically and horizontally; the expanded structures keep the original speed of the basic one. The MA conversion varies according to the AM selected expansion, ranging from 2²¹ to 2¹⁰⁰; 3) to solve the problem of fast real-time spectrum acquisition speed, fast electronics is used. Electronics is autonomous in the spectrum acquisition, updating and graphical phases, while it is under computer control in both phases of the system´s initialization and for transfer of the updated spectrum data from the MA buffer memory unit to the host; and 4) the system is constructed from commercially available components. Their high integration and speed have led to a powerful, compact, flexible instrumentation system while minimizing cost at the same time