Monolithic silicon JFET front-end for calorimetry

The buried layer process for integrating Si-JFETs on a monolithic substrate was proven to be very suitable in the realisation of low noise, radiation hard preamplifiers. Two preamplifier versions that differ for the resistivity of the channel region have been realised. The lower channel resistivity is employed in applications from room temperature to liquid krypton, while the higher one suits the operation at liquid argon temperature. The paper describes the essential features of the two types of preamplifier, including the radiation sensitivity to γ-rays and neutrons at room temperature and the noise performances at cryogenic temperature.