Low-Noise Preamplifier Design Considerations for Large Area High Capacitance Solid-State Neutron Detectors

In this paper, the design of a low noise charge sensitive preamplifier, suitable for high capacitance solid-state neutron detector arrays, is described. Noise considerations related to arraying multiple detectors in either series or parallel are also presented. Using the designed preamplifier, an energy resolution of 12 keV FWHM in Si is achieved with 1 nF equivalent detector capacitance and 10 μS shaping time. Additionally, a novel preamplifier topology, which utilizes a capacitance canceling input stage, is presented. Detailed analysis of the capacitance cancelling stage is discussed with special consideration given to its use with a charge sensitive preamplifier. Up to a 15% decrease in noise is demonstrated using the capacitance cancelling technique.