ABSTRACT
When using solid-state photodetectors in low-light measurements, the lowest detection limit is usually imposed by the noise associated with the front-end circuit. For example, typical p-i-n (PIN) silicon photodiodes exhibit very low noise levels related essentially to the uctuations in the leakage current of the reverse-biased p-n junction and generally referred to as parallel noise. In this case, the front-end noise, which contains essentially thermal and icker contributions, is predominant, especially for large values of the detector capacitance. A great deal of care must be devoted to the design of the charge-sensitive preamplier (CSA) and the shaping lter to achieve the desired performance in terms of energy resolution of the whole detection system [1, 2].
