[en] The Higgs bosons can be observed in the [90-130] GeV mass range in the channel h -> γγ if a high resolution electromagnetic calorimeter is used. The needed performances are met in the Pb W O₄ crystals. This thesis is devoted to the study of the first Pb W O₄ crystals (23 cm length) and their associated electronic equipment. Of crucial importance it was found to be the behaviour of these crystals under long radiation exposure. The understanding of the radiation effects, the crystal growth procedure mastering and the realization of a green light monitoring system of high performance were successful results obtained in the study described in this thesis. A rather high energy (0.6 % at 100 GeV) and position resolution was achieved by using a APD readout. In addition, the prototype of a final readout chain of large dynamic range and low consumption was built with very encouraging results. Concerning the APDs it was established that increasing the active surface and reduction of exceeding noise factor F improves significantly the stochastic term in the energy resolution. Besides, a complete readout chain comprising current preamplifiers, a linear compressing (multi-slope) system and a fast ADC (40 MHz), were found necessary to met the requirements imposed on the high performing Pb W O₄ calorimeter. Research and development works based on the pioneering studies described in this thesis devoted to the crystal calorimeters are underway