Page "Gamma spectroscopy" Paragraph 9

The voltage pulse produced by the detector ( or by the photomultiplier in a scintillation detector ) is shaped by a multichannel analyzer ( MCA ).

The multichannel analyzer takes the very small voltage signal produced by the detector, reshapes it into a Gaussian or trapezoidal shape, and converts that signal into a digital signal.

In some systems, the analog-to-digital conversion is performed before the peak is reshaped.

The analog-to-digital converter ( ADC ) also sorts the pulses by their height.

ADCs have specific numbers of " bins " into which the pulses can be sorted ; these bins represent the channels in the spectrum.

The number of channels can be changed in most modern gamma spectroscopy systems by modifying software or hardware settings.

The number of channels is typically a power of two ; common values include 512, 1024, 2048, 4096, 8192, or 16384 channels.

The choice of number of channels depends on the resolution of the system and the energy range being studied.