Speaker
Description
The next and current cryogenic experiments such as CUORE, CROSS and CUPID detect signals using thermistors operated at around $10\ mK$. To amplify the thermistor signals without impacting the resolution of the detector, the electronics needs to have very low series and parallel noise, especially at low frequencies, and high temperature stability. An ad-hoc amplification and digitalization electronics' chain has been developed to have these very characteristics, with the analog amplifier having $<50\ nV/\sqrt{Hz}\ @\ 0.1\ Hz$ input-referred noise, as well as $<50\ ppm/K$ gain thermal drift and $5\ \mu V/K$ output offset thermal drift, which is improved with a dedicated temperature-dependent feedback. The whole electronics' system is made of several mainboards containing each 12 pre-amplifiers with adjustable gain and offset, a second stage with programmable gain, a low pass filter and DAQ, a pulser used for calibration and for adjusting the thermistor operating temperature, and a precise and low noise linear power supply that outputs voltages for the analog circuitry. Since the signals from the thermistors are generally slow (up to tens of ms rise times) and the number of channels to be amplified is in the order of a few thousands, the electronics can be placed and operated at ambient temperature without being limited by the parasitic capacitances of the long cables connecting the front-end to the detector and the small space of the cryostat.
