Ionizing radiation detection device and tomodensitometry device comprising such a device

The invention relates to the detection of ionizing radiations, mainly high energy X-rays, enabling a radiation dose determination to be made, or the transparency measurement of an object to this radiation. A thin device extremely sensitive, even to very high energy photons, has been designed, hence a large number of detector cells can be assembled and a wide angle view obtained. This great integration possibility is of particular advantage in tomodensitometry since it enables the exposure time and the dose of radiation received to be reduced. To this effect, materials are used which greatly absorb the X and γ-rays and very little the visible radiations and which have good photoconduction properties, particularly bismuth oxide and its compounds. The crystal being fitted between crossed polarizer and analyzer, the intensity change of a luminous analysis beam of wave length lambda 0 is detected, for which the absorption factor of the material is low. This change of intensity depends on the ionizing radiation flux. Such a device applies in particular to the radiation dose emitted during a given time and the value of the spatially variable transparency of an object placed between the radiation source and this device