Room temperature differential voltage sensitive preamplifier for large mass bolometric detectors

The present version of the very front-end preampli"er which readouts an array of 20 large mass TeO 2 bolometric detectors is reported. It operates at room temperature and has low series and parallel noise. The thermal drift has been maintained at negligible levels thanks to a correcting circuit especially designed for this purpose. ( 2000 Elsevier Science B.V. All rights reserved

Low-noise, low drift, high precision linear bipolar (±10 V) voltage supply/reference for cryogenic front-end apparatus

A very simple linear bipolar (±10 V) voltage supply/reference (VS/R) featuring very low noise has been implemented. The noise is about 1 μVpp in a 0.1–10 Hz bandwidth, becoming, for the −10 V supply only, 1.3 μVpp at 1.5 A. The VS/R is based on commercial devices and has been designed to face the stringent requirement of very low drift systems. It features very good line regulation, less than 10 mV over 10 V at 1.5 A supply current, and very low drift, between 3 and 8 ppm/°C; it also shows large power supply rejection ratio (PSRR), >120 dB. The VS/R presented includes also safety circuits, to protect itself and the electronic equipment to be supplied in an actual experimental condition. It is protected against inversion of polarity and against under and over voltage at its inputs, and has a foldback current limiting circuit which shuts down the whole system if the current absorption lasts for some time. These protecting circuits acts on both outputs (±10 V), to maintain always the symmetry. From an analysis made on the data extracted from the measured noise spectra, it was possible to measure the dynamic output impedance, found mainly inductive, with a value of the order of 1 mH. The dc PSRR has been improved by about 20 dB with respect to the performances of the devices used, thanks to a very simple circuit solution

A self-buffered DC baseline restorer with quasi-ideal behavior

Abstract We present a DC baseline restorer featuring quasi-ideal behavior, capable of showing an undershoot of less than 0.023%. Its circuit structure allows using a single operational amplifier to realize both the buffering of the output signal, with line driving capability, and to discharge the decoupling capacitance. The operational amplifier in each working condition always remains in a closed-loop state, exploiting its full dynamic performance. The presented circuit allows the avoidance of an additional amplifying buffer stage, necessary, up to now, to drive a 50 Ω coaxial cable terminated at both ends

A very simple method to measure the input capacitance and the input current of transistors

Abstract We describe a method to measure the gate capacitance and the gate current of transistors at any temperature and at any operating condition. Discrimination between the total input capacitance and transfer reverse capacitance (gate to drain capacitance) is also possible with high accuracy. With this data the optimization of the signal to noise ratio and power dissipation can be achieved in the design of the front-end electronics for nuclear applications

Monolithic current-sensitive preamplifier for the Accordion LAr calorimeter

Abstract Monolithic current-sensitive preamplifiers matching large detector capacitances, suitable for the Accordion LAr calorimeter prototype, have been designed and fabricated in an ion-implanted GaAs MESFET process. After pulse shaping with an CR-RC 2 filter, the equivalent noise charge is at least a factor of 2 lower than the value reached so far with existing hybrids circuits, without increasing the power dissipation. This preamplifier has a fast response and large dynamic range. Results show that it is still possible to further reduce the noise and extend the dynamic range; this is likely to be obtained in a new version presently being developed

FAST FRONT-END ELECTRONICS FOR EXPERIMENTS USING SILICON CALORIMETERS AT SSC /LHC COLLIDERS

Abstract A fast VLSI preamplifier using HF2CMOS technology was designed and built. The preamplifier meets the requirements for silicon calorimetry application in experiments at hadron colliders SSC/LHC. The overall power consumption is less than 45 mW for a maximum output voltage swing of 5 V (≈ 7 ns rise time). The slew rate is about 700 V/μs for an input capacitance of 150 pF. The measured value of ENC (equivalent noise charge), for an RC-CR shaping time of 20 ns and an input capacitance of 150 pF, is 17 ke RMS

A very high performance stabilization system for large mass bolometerexperiments

Abstract CUORE is a large mass bolometric experiment, composed of 988 crystals, under construction in Hall A of the Gran Sasso Underground Laboratories (LNGS). Its main aim is the study of neutrinoless double beta decay of 130Te. Each bolometer is a 760 g crystal of Tellurium dioxide on which a Nuclear Transmutation Doped Ge thermistor, Ge NTD, is glued with proper thermal contact. The stability of the system is mandatory over many years of data taking. To accomplish this requirement a heating resistor is glued on each detector across which a voltage pulse can be injected at will, to develop a known calibrated heating power. We present the design solution for a pulse generator system to be used for the injection of such a small and short voltage pulse across the heaters. This system is composed by different custom PCB boards each of them having multi-channel independent outputs completely remotely programmable from the acquisition system, in pulse width and amplitude, through an on-board ARM7 microcontroller. Pulse amplitudes must be selectable, in order to handle each detector on its full dynamic range. The resolution of the output voltage is 12 bits over 10 V range. An additional 4 steps programmable voltage attenuator is added at every output. The width of any pulse can range from 100 μ s to 25.5 ms. The main features of the final system are: stability and precision in pulses generation (at the level of less than a ppm/°C), low cost (thanks to the use of commercial components) and compact implementation