Very low cost multichannel analyzer with some additional features

In this paper we present a multichannel analyzer (MCA) based on a digital signal controller (DSC). The multichannel analyzer is characterized by a very low cost and an additional feature of recording time intervals between pulses. The total cost of electronic parts used in construction of the MCA is around 50 USD. The electronic circuit is based on dsPIC30F2020 DSC unit from Microchip. The device has a 10-bit analogue-to-digital converter (ADC) which can sample and convert 2 samples per μs. The DSC samples the input voltage continuously and detects incoming pulses. The data belonging to a detected pulse and its time stamp are sent to a PC on-line. The analysis of data stored on the PC is performed off-line with the help of a genetic algorithm (GA) used to fit the pulse shape function. This allows determination of amplitude of each individual pulse. The effective resolution varies with the pulse length and is typically 1000 channels for pulses approximately 4μs long.