A comparative analysis of multichannel data acquisition systems for quality assurance in external beam radiation therapy

The paper presents a comparative study performed by the Centre of Medical Radiation Physics (CMRP) on three multichannel Data Acquisition Systems (DAQ) based on different analogue front-ends to suit a wide range of radiotherapy applications. The three front-ends are: a charge-to-frequency converter developed by INFN Torino, an electrometer and a charge-to-digital converter (both commercial devices from Texas Instruments). For the first two (named DAQ A and B), the CMRP has designed the read-out systems whilst the third one (DAQ C) comes with its own evaluation board. For the purpose of the characterization DAQ A and DAQ B have been equipped with 128 channels while DAQ C has 256 channels. In terms of performances, the DAQs show good linearity over all the dynamic range. Each one has a different range of sensitivity ranging from less than 1 pC up to 13 nC, which makes the three front-ends complementary and suitable for use with different radiation detectors for different radiotherapy applications, or in a mixed solution which can house different front-ends.