A novel system formed by a Microwave Superconducting Quantum Interference Device (SQUID) Multiplexer (
μ
MUX) and a room temperature electronics employs frequency division multiplexing (FDM) ...technique to read out multiple cryogenic detectors. Since the detector signal is embedded in the phase of the SQUID signal, a Digital Quadrature Demodulator (DQD) is widely implemented to recover it. However, the DQD also generates a signal that aliases into the first Nyquist zone affecting the demodulated detector signal. In this work, we demonstrate how this spurious signal is generated and a mathematical model of it is derived and validated. In addition, we discuss different proposals to improve the attenuation of this undesired signal. Lastly, we implement one of the proposals in our readout system. Our measurements show an enhancement in the spurious signal attenuation of more than 35 dB. As a result, this work contributes to attenuate the spurious below the system noise.
We describe a technique to optimize the dynamic performance of microwave SQUID multiplexer (µMUX)-based systems. These systems proved to be adequate for reading out multiple cryogenic detectors ...simultaneously. However, the requirement for denser detector arrays to increase the sensitivity of scientific experiments makes its design a challenge. When modifying the readout power, there is a trade-off between decreasing the signal-to-noise ratio (SNR) and boosting the nonlinearities of the active devices. The latter is characterized by the spurious free dynamic range (SFDR) parameter and manifests as an increment in the intermodulation products and harmonics power. We estimate the optimal spectral location of the SQUID signal containing the detector information for different channels. Through the technique, what we refer to as
Spectral Engineering
, it is possible to minimize the SNR degradation while maximizing the SFDR of the detector signal, thus, overcoming the trade-off.
This work reports the performance evaluation of an SDR readout system based on the latest generation (Gen3) of AMD’s Radio-Frequency System-on-Chip (RFSoC) processing platform, which integrates a ...full-stack processing system and a powerful FPGA with up to 32 high-speed and high-resolution 14-bit Digital-to-Analog Converters and 14-bit Analog-to-Digital Converters. The proposed readout system uses a previously developed multi-band, double-conversion IQ RF-mixing board targeting a multiplexing factor of approximately 1000 bolometers in a bandwidth between 4 and 8 GHz, in line with state-of-the-art microwave SQUID multiplexers. The characterization of the system was performed in two stages, under the conditions typically imposed by the multiplexer and the cold readout circuit: first, in transmission, showing that noise and spurious levels of the generated tones are close to the values imposed by the cold readout, and second, in RF loopback, presenting noise values better than −100 dBc/Hz totally in agreement with the state-of-the-art readout systems. It was demonstrated that the RFSoC Gen3 device is a suitable enabling technology for the next generation of superconducting detector readout systems, reducing system complexity, increasing system integration, and achieving these goals without performance degradation.
Optical crosstalk in SiPMs Hampel, M.R.; Fuster, A.; Varela, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2020, Letnik:
976
Journal Article
Recenzirano
It was observed that the optical crosstalk probability (CT) of the silicon photomultipliers (SiPMs) of the electronics in all the AMIGA muon counter modules installed at the Pierre Auger Observatory ...was reduced by a factor of ∼2.68 after its deployment. This effect motivated the study of the optical crosstalk in SiPMs, in particular, the external interface optical crosstalk (EICT). In this paper, two laboratory measurements were performed to evaluate the CT, and a model to simulate the EICT is proposed. We show that combining CT measurements with simulations, the EICT can be precisely estimated. We also obtained the internal optical crosstalk of the tested SiPM and it was (1.27±0.05)%. This study shows that the thickness of the protective window of the SiPM and the optical system to which the SiPM is coupled affects optical crosstalk. We conclude that the EICT is not negligible and for some cases it is the main contribution to the total optical crosstalk in SiPMs. Taking advantage of the CT variations depending on the optical system to which the SiPM is connected, we propose a method to validate the proper installation of the electronics in the muon counters modules of AMIGA.
The hybrid design of the Pierre Auger Observatory allows for the measurement of the properties of extensive air showers initiated by ultra-high energy cosmic rays with unprecedented precision. By ...using an array of prototype underground muon detectors, we have performed the first direct measurement, by the Auger Collaboration, of the muon content of air showers between Formula omitted and Formula omitted eV. We have studied the energy evolution of the attenuation-corrected muon density, and compared it to predictions from air shower simulations. The observed densities are found to be larger than those predicted by models. We quantify this discrepancy by combining the measurements from the muon detector with those from the Auger fluorescence detector at Formula omitted and Formula omitted. We find that, for the models to explain the data, an increase in the muon density of Formula omitted Formula omitted Formula omitted for EPOS-LHC, and of Formula omitted Formula omitted Formula omitted for QGSJetII-04, is respectively needed.
The extraction of Hg(II) from 0.1 M KNO
3 by the commercial extractant LIX 34 dissolved in toluene has been studied as a function of the equilibrium pH and total concentrations of extractant and ...Hg(II). Experimental data, treated both graphically and numerically, can be explained by assuming the extraction of the species Hg
2L
2 (HL=4-dodecyl-
N-8-quinolinyl-benzenesulphonamide), where the central ion seems to be Hg
2
2+. Finally, as an application of this study, mercury removal from contaminated sludge was carried out and extraction percentages over 95% were achieved.