“CUBE”, A low-noise CMOS preamplifier as alternative to JFET front-end for high-count rate spectroscopy

We present a monolithic CMOS charge preamplifier named “CUBE”. It is specifically designed to be used with Silicon Drift Detectors (SDD). We will show that the use a MOSFET as input transistor allows superior noise performances at very short shaping times respect to the state-of-the-art externally connected JFET devices. We will show the achievable energy resolutions using a 10mm² reference SDD with different count-rates and with different analog and digital commercial filters. A state-of-the-art energy resolution (for a silicon detector) of 125 eV at 6 keV has been achieved with the optimum shaping time. Moreover, it will be shown that CUBE enables the use of an extremely fast-peaking time of only 100 ns with extraordinary good energy resolution of 149 eV. As a consequence we can state that, the CUBE preamplifier is very well suited for high count-rate spectroscopy applications. An example of the performance with output countrate up to 490 kcps will be reported.