In the mid-19th century, the scientific community was convinced that physics had been fully discovered and only isolated, peripheral issues remained unexplained. One of these was black body radiation ...(CDC) and the transformation of electromagnetic waves. In 1893, Wien proved that the wavelength at which CDC radiates the greatest amount of energy is inversely proportional to body temperature. Surprisingly, the formula resulting from current, reliable physics describes CDC radiation very well only at low frequencies. For ultraviolet frequencies, the obtained function was constantly upwards. Planck proposed the distribution of the CDC radiation spectrum, assuming that the radiation can only be emitted in precisely defined portions known as quanta. This was the year of the creation of quantum physics, one of the foundations of modern physics. Aristotle recognized that there is a distinctive frame of reference. This view was challenged by Galileo, who concluded that the speed and position of the body are relative. The Galilean transformation became the foundation of Newtonian physics. However, Maxwell’s equations describing electromagnetic waves were not subject to the Galilean transformation but rather to the Lorentz transformation. The biggest problem at the beginning of the 20th century was the incompatibility of the laws of dynamics and electromagnetism. The theory of relativity is another foundation of modern physics. The last year of the 19th century debunked the myth of full understanding of the laws of nature. It quickly turned out that the knowledge about the universe at that time was very little. This lack of knowledge led to a rapid reconstruction of physics in the first half of the 20th century. is book discusses some of these subjects, including spinor fields, 5D relativity, dissipative quantum system and energy balance, centrifugal acceleration in relativistic astrophysics, and time-dependent photoluminescence.
Quantum chromodynamics is a quantum field theory that describes strong interactions between quarks and gluons. It is the SU(3) gauge theory of the current Standard Model for elementary particles and ...forces. The book contains several chapters on such topics as quark mixing, the double pole method, the inter-nucleon up-to-down quark bond and its implications for nuclear binding, and more. Readers should be fluent in advanced mathematics and quantum physics. Knowledge of quantum electrodynamics is welcome.
Measurements in present experiments have dramatically advanced our understanding of ultrahigh-energy cosmic rays. The suppression of the flux at the highest energies is now confirmed without any ...doubt, and strong limits have been placed on the photon and neutrino components. There are indications for a small, large-scale anisotropy both below and above the energy of the angle and for a correlation on smaller angular scales at E > 5.5*1019 eV. Around 3*1018 eV, there is a distinct change of slope with energy, and the shower-to-shower variance decreases. Interpreted with the leading LHC-tuned shower models, this implies a gradual shift to a heavier composition, and a number of fundamentally different astrophysical model scenarios have been developed to describe this evolution.
The article presents the FPGA implementation of 256- and 768-stage Least Mean Squares filters with rectangular, Hamming and Kaiser windows to suppress at least ten narrowbands RFIs. The analysis ...shows extremely high-efficiency Radio Frequency Interference (RFI) elimination. For a proof of concept study, we used 9-bit real cosmic ray data from the Auger Engineering Radio Array (AERA) as patterns and mixed with 14-bit multiple narrow-band RFIs. They were hidden deep within RFI’s background. After the cleaning process, the patterns were brought out and have shown practically without contamination.
The article presents the FPGA implementation of 256- and 768-stage Least Mean Squares filters with rectangular, Hamming and Kaiser windows to suppress at least 10 narrow-bands RFIs. The analysis ...shows extremely high efficiency Radio Frequency Interference (RFI) elimination. 9-bit real cosmic ray data from the Auger Engineering Radio Array (AERA) was used as patterns and mixed with 14-bit multiple narrow-band RFIs. They were hidden deep within RFI's background. After the cleaning process, the patterns were brought out and are practically without contamination.
Radio stations of the Auger Engineering Radio Array (AERA) investigates radio signals from coherent emissions due to geomagnetic radiation and charge excess processes. The frequency band is limited ...to 30–80 MHz. In order to improve the signal to noise ratio, RFI filters have to be used to suppress this contamination.
The paper compares several (currently in use and proposed) RFI filters. We analyzed: the non-adaptive filter (IIR notch) as well as adaptive filters: IIR notch supported by the virtual NIOS® processor, FIR based on the linear prediction supported by the virtual NIOS® processor and finally the Least Mean Square filter. The LMS filter proposed for the RFI suppression should use correct learning factor, crucial for a stability of the filter, which could be determined by eigenvalues of the auto-correlation matrix built for ADC samples.
For typical AERA configuration (4 beacons with fixed frequencies) the best filter seems to be the IIR as introducing very high suppression efficiency with relatively low distortions and low energy consumption. However, when unexpected RFI appears it is worth consider a combination of fixed frequency IIR + IIR filter supported with NIOS processor identifying additional RFI source as well as FIR filters. LMS filters can be used when very fast response on new sources is needed.
Radio stations of the Auger Engineering Radio Array (AERA) investigates radio signals from coherent emissions due to geomagnetic radiation and charge excess processes. The frequency band is limited ...to 30–80 MHz. This range is highly contaminated by human-made RFI. In order to improve the signal to noise ratio, RFI filters have to be used to suppress this contamination.
The LMS filter proposed for the RFI suppression should use correct learning factor, crucial for a stability of the filter, which could be determined by eigenvalues of the auto-correlation matrix built for ADC samples.
A detailed analysis of almost one million of AERA events confirms that eigenvalues of real cosmic events taken from the AERA database fully allow their use in the LMS filters, with learning factors optimal for the most efficient RFI suppression.
This type of the filter can be used in other radio cosmic ray experiments e.g. the Giant Radio Array for Neutrino Detection (GRAND).
The production of radio waves from extensive air showers (EASs), initiated by ultra-high-energy cosmic rays, has been attributed to geomagnetic emission and charge excess processes. These days, the ...radio detection technique is used in many experiments aimed at studying EAS. One of them is the Auger Engineering Radio Array (AERA), located within the Pierre Auger Observatory. The frequency band observed by AERA radio stations is 30-80 MHz. The investigated frequency range is often very contaminated by human-made and narrowband radio-frequency interference (RFI). Suppression of these contaminations is crucial to lowering the rate of spurious triggers. An adaptive filter based on the least mean squares (LMS) algorithm can be an alternative one for currently used infinite impulse response (IIR)-notch nonadaptive filters. Measurements show that the LMS filter is very efficient in suppressing RFI and only slightly distorts radio signals. This article presents the 32-stage filters based on a transposed finite impulse response (FIR) filter implemented into cost-effective CycloneIV and CycloneV Altera field-programmable gate arrays (FPGAs) with a sufficient safety margin of the timing performance for the global clock above 200 MHz to obey the Nyquist requirement.
The standard first level triggers in the surface detectors analyzing data in the field-programmable gate array (FPGA) just after the digitization in analog to digital converters (ADCs) of the Pierre ...Auger Observatory were developed when FPGA was relatively simple and additionally expensive. A huge progress in electronics allows an implementation of very sophisticated mathematical algorithms in very powerful (a lot of FPGA fabric, embedded memories, and digital signal processing (DSP) blocks with very fast embedded multipliers) and relatively inexpensive FPGAs. A fuzzy logic (FL) is an alternative approach for a trigger based on a discrete cosine transform or artificial neural networks developed for the surface detector of the Pierre Auger Observatory. The aim of this article is to report on the trigger design that would allow one to distinguish the signal profiles from the Auger photo-multipliers (PMTs) of the water Cherenkov detectors originating from the neutrino-induced atmospheric showers with a high background of the proton showers. The algorithm has been successfully implemented in CycloneV and Arria10 FPGAs with reasonable resource occupancy and sufficient margin of a registered performance by 120 MHz sampling frequency. The FL trigger may support existing triggers in the Auger surface detector being optimized to identify neutrino-generated showers.
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