Monolithic junction field-effect transistor charge preamplifier for calorimetry at high luminosity hadron colliders

The outstanding noise and radiation hardness characteristics of epitaxial-channel junction field-effect transistors (JFETs) suggest that a monolithic amplifier based upon them may be able to meet the strict specifications for calorimetry at high luminosity colliders. Results obtained so far with a buried layer planar technology, among them an entire monolithic charge-sensitive preamplifier, are described. The buried layer process seems to have provided a viable approach to the design of monolithic JFET preamplifiers of outstanding noise characteristics. Tests carried out on a preamplifier employing at the input a JFET with 11400- mu m gate width have demonstrated that the noise behavior of the preamplifier is close to that which would be expected if the total noise referred at the preamplifier input were the thermal noise in the input device; that is, the monolithic circuit approaches the noise performances of a hybrid preamplifier using discrete JFETs.<>