|A stream of linear pulses, usually unipolar, leaves the
amplifier. The final electronic problem is to sort these according to
their pulse height, the pulse height being proportional to the gamma ray
energy deposited in the detector. This is done using a single channel
analyser. Two voltage levels are set up, the lower level discriminator (LLD), H1,
and the upper level discriminator (ULD), H2.Such a device would give
an output pulse for every input pulse whose maximum falls into the voltage
slot or window of H2 - H1.
A multi-channel analyser is made of banks of single-channel analysers
where the ULD of one window is the LLD of the next.
On the next page, there is an active
simulation of an MCA.