The Mirion Intelligent Preamplifier (iPA) for High-Purity Germanium (HPGe) Detectors is a low-noise, high-speed resistive feedback preamplifier designed for high resolution gamma spectroscopy and timing measurements. When energy is deposited in the detector, the iPA detector converts the charge to a step-function output pulse of which the amplitude is proportional to the total charge accumulated in the event.
The preamplifier includes a low-noise FET input circuit optimized for the ultra-high source impedance of germanium detectors. A protection network prevents damage to the preamplifier input from high voltage transients. The charge amplifier and buffer stages have been designed for both the low noise and high speed performance needed for precise energy and timing spectroscopy. In addition, special circuits monitor both the temperature and activity of the detector, and warn when improper operating conditions exist.
The iPA detector is equipped with a high-speed USB 2.0 serial data interface. This interface facilitates extensive control and monitoring of many critical preamplifier and detector functions. The included iPA Control Panel software application provides the user with real-time monitoring of the detector current and temperature, along with pertinent internal preamplifier operating voltages. The integrated data logging feature continuously records several of these key operating parameters on a periodic basis, and stores them within the iPA detector mass storage memory. The stored data log files can be readily downloaded and viewed. This allows the user to take preventative measures if a key parameter starts to shift and ultimately improves equipment availability and productivity. A standard test input and internal test pulser are provided to assist system setup and as a diagnostic aid. The internal test pulser is digitally-controlled through the iPA Control Panel software.
The iPA detector also includes an integrated LN2 level monitoring circuit, for use with an optional Mirion capacitive LN2 level-sensing probe. The iPA detector and probe work together to continuously measure the LN2 level within the Dewar. The measurement is displayed on the iPA Control Panel status screen, and warns the user when the LN2 level becomes low and the Dewar requires refilling.