Abstract: A velocity transducer or Velomitor® that can output electrical signals relating to vibration, despite the transducer being exposed to low levels of gamma-radiation, is disclosed. A DC feedback circuit, which sets up the input stage bias point, keeps the output bias voltage within a usable voltage range as the transducer is exposed to the gamma-radiation. An additional JFET transistor, configured as a current source, helps the DC feedback circuit compensate for increases in the offset voltage of the JFET amplifier. The value of a resistor controlling the gate current of the JFET amplifier is also reduced, such that when the leakage current increases, the offset voltage is reduced.

Abstract: A velocity transducer or Velomitor® that can output electrical signals relating to vibration, despite the transducer being exposed to low levels of gamma-radiation, is disclosed. A DC feedback circuit, which sets up the input stage bias point, keeps the output bias voltage within a usable voltage range as the transducer is exposed to the gamma-radiation. An additional JFET transistor, configured as a current source, helps the DC feedback circuit compensate for increases in the offset voltage of the JFET amplifier. The value of a resistor controlling the gate current of the JFET amplifier is also reduced, such that when the leakage current increases, the offset voltage is reduced.

Abstract: An instrumentation package in broad terms includes at least one substantially cylindrical instrumentation component; a substantially cylindrical shield surrounding the instrumentation component, the shield having a diameter less than a standard predetermined diameter; and a sizing sleeve around the shield, thereby increasing the diameter of the sleeve to the standard predetermined diameter. A nuclear detector package is also disclosed that includes a substantially cylindrical crystal element; a photomultiplier tube arranged coaxially with the crystal element; an optical coupler sandwiched between one end of the crystal element and an adjacent end of the photomultiplier tube; the crystal element, optical coupler and photomultiplier tube hermetically sealed within a cylindrical shield; and a flexible support sleeve extending exteriorly along the crystal element and the photomultiplier tube and radially inside the cylindrical shield.