The electrostatic transformer

Abstract

The electrostatic transformer (EST) has been developed to match the large-capacitance hadronic signal towers of liquid ionization calorimeters to relatively low-capacitance, low-noise preamplifiers. The intrinsically fast internal impedance transformation by the EST preserves the fast rise time required for effective calorimetry in the high-rate environment of the SSC/LHC. Another advantage of the EST over an external ferrite-core transformer (FTC) is that the former is unaffected by the large magnetic field required in most detector configurations. The performance of the EST is limited primarily by crosstalk to neighboring towers, which delocalizes the signal and degrades the signal to noise ratio. In practical applications both these effects can be made small. To aid in the evaluation and design of useful ESTs we have studied an aluminum model of a hadronic tower section of typical dimensions. The measurements on the model agree well with calculations using a simple electrical model.