Preliminary test of Medisoft 4: control software for the Medipix2 read-out chip

We present here preliminary tests of Medisoft 4, a software procedure for the control and the read-out of the single photon counting radiation imaging systems based on the Medipix2 chip (256/spl times/256 pixels, 55 /spl mu/m pitch). The system has been developed in the framework of the Medipix2 collaboration. This hardware and software system is the successor of the system based on the Medipix1 photon counting chip (64/spl times/64 pixels, 170 /spl mu/m pitch). Following the Medipix system evolution, Medisoft 4 allows the user to access the new implemented features, such as the higher resolution, the faster data communication rates, the daisy-chain multichip mode, the energy windowed acquisition, the continuous acquisition mode, the double signal polarity (holes and electrons), etc. The readout of the data from the Medipix2 chip is presently via the chip serial bus through a MUROS2 interface board and a commercial I/O board, but parallel read-out via a MPRS dedicated interface is also foreseen. The current version (Medisoft 4.0) - here the subject of preliminary tests connected via MUROS2 to a Medipix2 chip not bump-bonded to any detector - reads out only single chips and features a reduced set of functionalities. Future versions will read up to eight chips in daisy chain and provide full system performance, including high frame rate acquisitions and spectroscopic imaging. After description of the Medipix2 chip, its read-out interfaces and the Medisoft 4 software architecture, we show the results of preliminary software tests on serial communication protocol and speed with MUROS2 and Medipix2, analogue test-input, internal DACs calibration, threshold uniformity.