Development of charge sensitive amplifiers based on various circuit board substrates and evaluation of radiation hardness characteristics

Abstract

Ultra-low noise charge sensitive amplifiers (CSAs) based on various types of circuit board substrates, such as FR4, Teflon, and ceramics (Al2O3) with two different designs, PA1 and PA2, have been developed. They were tested to see the noise effect from the dielectric loss of the substrate capacitance before and after irradiation. If the electronic noise from the CSAs is to be minimized and the energy resolution enhanced, the shaping time has to be optimized for the detector, and a small feedback capacitance of the CSA is favorable for a better SNR. Teflon- and ceramic-based PA1 design CSAs showed better noise performance than the FR4-based one, but the Teflon-based PA1 design showed better sensitivity than ceramic based one at a low detector capacitance (<10 pF). In the PA2 design, the equivalent noise and the sensitivity were 0.52 keV FWHM for a silicon detector and 7.2 mV/fC, respectively, with 2 μs peaking time and 0.1 pF detector capacitance. After 10, 100, 103, 104, and 105 Gy irradiation the ENC and sensitivity characteristics of the developed CSAs based on three different substrate materials are also discussed.