The Amptek A250CF “Cool FET” Charge Sensitive Preamplifier is the lowest noise, general purpose, preamplifier available. It is designed to give the ultimate performance when used with either low or high detector capacitance detectors and is a direct replacement for other higher noise charge sensitive preamplifiers. The A250CF “Cool FET” technology uses a Peltier cooler to keep the input FET(s) at -50 °C. Cooling is totally transparent to the user. The A250CF “CoolFET” will be available in the summer of 2003.