Readout architecture of a highly segmented silicon calorimeter operating in space

We present the design of a readout system for a silicon calorimeter with 12800 readout channels, to be operated on satellite or balloon-borne experiments for cosmic antiproton and antihelium search. A prototype of the calorimeter digital readout system has been designed and constructed. It may be subdivided into two main parts: the storage modules and the controller. Performance tests of the prototype at the acquisition rate of 8 MHz result in a very limited power consumption, amounting to 0.1 mW per channel for the Storage Modules and 0.5 W for the controller. The acquisition rate can be further enhanced by simple modifications of the transmission protocol between the storage modules and the controller. This readout system can be easily adapted to other detectors to be operated on space vehicles. An enhanced version of this prototype is presently used in a ? spectroscopy balloon-borne experiment.