In this work, direct measurements of the muon density at 1000 m from the shower axis obtained by the Akeno Giant Air Shower Array (AGASA) are analyzed. The selected events have zenith angles θ≤36° ...and reconstructed energies in the range 18.83≤log10(ER/eV)≤19.46. These are compared to the predictions corresponding to proton, iron, and mixed composition scenarios obtained by using the high-energy hadronic interaction models EPOS-LHC, QGSJetII-04, and Sibyll2.3c. The mass fractions of the mixed composition scenarios are taken from the fits to the depth of the shower maximum distributions performed by the Pierre Auger Collaboration. The cross-calibrated energy scale from the Spectrum Working Group D. Ivanov, for the Pierre Auger Collaboration and the Telescope Array Collaboration, PoS(ICRC2017) 498 (2017) is used to combine results from different experiments. The analysis shows that the AGASA data are compatible with a heavier composition with respect to the one predicted by the mixed composition scenarios. Interpreting this as a muon deficit in air shower simulations, the incompatibility is quantified. The muon density obtained from AGASA data is greater than that of the mixed composition scenarios by a factor of 1.49±0.11(stat)±0.18(syst), 1.54±0.12(stat)±0.18(syst), and 1.66±0.13(stat)±0.20(syst) for EPOS-LHC, Sibyll2.3c, and QGSJetII-04, respectively.
The origin and nature of the ultrahigh energy cosmic rays remains a mystery. However, considerable progress has been achieved in past years due to observations performed by the Pierre Auger ...Observatory and Telescope Array. Above 1018 eV the observed energy spectrum presents two features: a hardening of the slope at ∼1018.6 eV, which is known as the ankle, and a suppression at ∼1019.6 eV. The composition inferred from the experimental data, interpreted by using the current high energy hadronic interaction models, seems to be light below the ankle, showing a trend to heavier nuclei for increasing values of the primary energy. Also, the anisotropy information is consistent with an extragalactic origin of this light component that would dominate the spectrum below the ankle. Therefore, the models that explain the ankle as the transition from the galactic and extragalactic components are disfavored by present data. Recently, it has been proposed that this light component originates from the photodisintegration of more energetic and heavier nuclei in the source environment. The formation of the ankle can also be explained by this mechanism. In this work, we study in detail this general scenario, but in the context of the central region of active galaxies. In this case, the cosmic rays are accelerated near the supermassive black hole present in the central region of these types of galaxies, and the photodisintegration of heavy nuclei takes place in the radiation field that surrounds the supermassive black hole.
The Argentine stretch of the del Plata basin crosses regions devoted to extensive and intensive agriculture mostly with chemical pest control. The utilization of pesticides in the region has ...increased 900% in the last two decades associated with the introduction of biotech crops and direct-seeding techniques. Our objective was to study the occurrence, concentration, and fate of pesticides in surface water and bottom sediments of the principal tributaries and main watercourse of the Paraguay-Paraná River. We sampled 22 sites in the distal positions of the main affluents and main watercourse of the Paraná and report here results from two monitoring campaigns (2010–2012). Surface water and bottom sediments were analyzed according to standardized methods by matrix-solid-phase dispersion and liquid-liquid extraction, respectively. Twenty-three pesticide compounds were analyzed by gas chromatography. The results from both campaigns indicated a generalized but variable distribution in the concentrations detected throughout the basin. The ranges of total measured pesticide concentrations in water and sediments were, respectively, 0.004–6.62 μg/l and 0.16–221.3 μg/kg dry weight. Endosulfans, cypermethrin, and chlorpyrifos were ubiquitous compounds in both environmental compartments and quantitatively the most relevant. All concentrations detected in water were over the recommended guidelines for the protection of aquatic biota. The partitioning indicated a higher affinity for the sediments. Agricultural activity is the source of pesticide-pollution loads, transported by tributaries that reach the main watercourse and alter the quality of the aquatic ecosystem.
The origin and nature of ultrahigh energy cosmic rays remains a mystery. However, great progress has been made in recent years due to the observations performed by the Pierre Auger Observatory and ...Telescope Array. In particular, it is believed that the composition information of the cosmic rays as a function of the energy can play a fundamental role for the understanding of their origin. The best indicators for primary mass composition are the muon content of extensive air shower and the atmospheric depth of the shower maximum. In this work we consider a maximum likelihood method to perform mass composition analyses based on the number of muons measured by underground muon detectors. The analyses are based on numerical simulations of the showers. The effects introduced by the detectors and the methods used to reconstruct the experimental data are also taken into account through a dedicated simulation that uses as input the information of the simulated showers. In order to illustrate the use of the method, we consider AMIGA (Auger Muons and Infill for the Ground Array), the low energy extension of the Pierre Auger Observatory that directly measures the muonic content of extensive air showers. We also study in detail the impact of the use of different high energy hadronic interaction models in the composition analyses performed. It is found that differences of a few percent between the predicted number of muons have a significant impact on composition determination.
QUBIC I: Overview and science program Mousset, L.; Battistelli, E.S.; de Bernardis, P. ...
Journal of cosmology and astroparticle physics,
04/2022, Letnik:
2022, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Abstract
The Q & U Bolometric Interferometer for Cosmology (QUBIC) is a novel kind of polarimeter optimized for the measurement of the B-mode polarization of the Cosmic Microwave Background (CMB), ...which is one of the major challenges of observational cosmology. The signal is expected to be of the order of a few tens of nK, prone to instrumental systematic effects and polluted by various astrophysical foregrounds which can only be controlled through multichroic observations. QUBIC is designed to address these observational issues with a novel approach that combines the advantages of interferometry in terms of control of instrumental systematic effects with those of bolometric detectors in terms of wide-band, background-limited sensitivity. The QUBIC synthesized beam has a frequency-dependent shape that results in the ability to produce maps of the CMB polarization in multiple sub-bands within the two physical bands of the instrument (150 and 220 GHz). These features make QUBIC complementary to other instruments and makes it particularly well suited to characterize and remove Galactic foreground contamination. In this article, first of a series of eight, we give an overview of the QUBIC instrument design, the main results of the calibration campaign, and present the scientific program of QUBIC including not only the measurement of primordial B-modes, but also the measurement of Galactic foregrounds.
We give forecasts for typical observations and measurements: with three years of integration on the sky and assuming perfect foreground removal as well as stable atmospheric conditions from our site in Argentina, our simulations show that we can achieve a statistical sensitivity to the effective tensor-to-scalar ratio (including primordial and foreground B-modes)
σ
(
r
)=0.015.
The underground muon detector of the Pierre Auger Observatory is aimed at attaining direct measurements of the muonic component of extensive air showers produced by cosmic rays with energy from ...1016.5 eV up to the region of the ankle (around 1018.7 eV). It consists of two nested triangular grids of underground scintillators with 433 m and 750 m spacings, and a total of 71 positions, each with 192 scintillator strips (30 m2) deployed 2.3 m underground. The light produced by impinging muons in the scintillators is propagated with optical fibers towards an array of silicon photomultipliers. In this work, we present the development, validation, and performance of an end-to-end tool for simulating the response of the underground muon detector to single-muon signals, which constitutes the basis for further simulations of the whole array. Laboratory data and simulation outcomes are found consistent, showing that with the underground muon detector we can measure single muons, with an efficiency of 99%, up to about 1050 particles arriving at exactly the same time in 30 m2 of scintillator.
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.
Abstract
In this work we present an application of the Goertzel
Filter for the channelization of multi-tonal signals, typically used
for the read-out of cryogenic sensors which are multiplexed in the
...frequency domain (FDM), by means of Microwave Superconducting
Quantum Interference Device (SQUID) Multiplexer (μMUX). We
demonstrate how implementing a bank of many of these filters, can be
used to perform a channelization of the multi-tonal input signal to
retrieve the data added by the sensors. We show how this approach
can be implemented in a resource-efficient manner in a Field
Programmable Gate Array (FPGA) within the state-of-the-art, which
allows great scalability for reading thousands of sensors; as is
required by Radio Telescopes in Cosmic Microwave Background
Radiation (CMB) surveys using cryogenic bolometers, particles
detection like Neutrino mass estimation using cryogenic calorimeters
or Quantum Computing.
The transition between the Galactic and extragalactic cosmic ray components could take place either in the region of the spectrum known as the second knee or in the ankle. There are several models of ...the transition but it is not possible to confirm or even rule out any of them from the flux measurement alone. Therefore, the measurement of the composition as a function of primary energy will play a fundamental role for the understanding of this phenomenon.
In this work we study the possibility of primary identification in an event by event basis in the ankle region, around
E
=
10
18
eV
. We consider as case study the enhancements of the Pierre Auger Southern Observatory, which are under construction in Malagüe, Province of Mendoza, Argentina. We use a non-parametric technique to estimate the density functions, from Monte Carlo data, corresponding to different combination of mass sensitive parameters and type of primaries. These estimates are used to obtain the classification probability of protons and iron nuclei for the different combination of parameters considered. We find that, after considering all relevant fluctuations, the maximum classification probability obtained combining surface and fluorescence detectors parameters is of order of 90%.
PDF
