[en] The detector, eg of cadmium telluride, mercury iodide or germanium, supplies an integrating preamplifier followed by a linear amplifier and a differential amplifier. Carrier collection time is determined by a constant fraction discriminator and a time to amplitude convertor. Analogue multiplying and adding circuits and a variable gain amplifier allow the charge arising from the X or gamma rays to be corrected using the carrier collection time and the result is fed to a processing and display unit. The equipment is controlled by a console giving access to various measuring points and selection and regulating circuits