ABSTRACT
The expected volume of data from the third-generation gravitational waves (GWs) Einstein Telescope (ET) detector would make traditional GWs search methods such as match filtering ...impractical. This is due to the large template bank required and the difficulties in waveforms modelling. In contrast, machine learning (ML) algorithms have shown a promising alternative for GWs data analysis, where ML can be used in developing semi-automatic and automatic tools for the detection and parameter estimation of GWs sources. Compared to second generation detectors, ET will have a wider accessible frequency band but also a lower noise. The ET will have a detection rate for Binary Black Holes (BBHs) and Binary Neutron Stars (BNSs) of the order of 105–106 and 7 × 104 yr−1, respectively. We explored the efficiency of using convolutional neural networks (CNNs) for the detection of BBHs’ mergers in synthetic noisy data that was generated according to ET’s parameters. Without performing data whitening or applying bandpass filtering, we trained four CNN networks with the state-of-the-art performance in computer vision, namely VGG, ResNet, and DenseNet. ResNet has significantly better performance, and was able to detect BBHs sources with SNR of 8 or higher with 98.5 per cent accuracy, and with 92.5 per cent, 85 per cent, 60 per cent, and 62 per cent accuracy for sources with SNR range of 7–8, 6–7, 5–6, and 4–5, respectively. ResNet, in qualitative evaluation, was able to detect a BBH’s merger at 60 Gpc with 4.3 SNR. It was also shown that CNN can be used efficiently for near-real time detection of BBHs.
The use of a Helmholtz resonator as a photoacoustic cell has many advantages. Its main drawback in high-sensitivity photoacoustic measurements is the relatively low values of Q-factors of such cells. ...One of the important loss sources which limit the quality factor of photoacoustic Helmholtz resonators is the rapid change of the cross section at the cavity–duct boundaries. This paper presents a design of a cell in which the shape of the duct was modified in such a way that the cross-section change is more gradual. A presented comparison of measurements of the Q-factors shows clearly that the Q-factor of the cell can be improved by almost a factor of two by such a modification of the duct shape.
Matra Gravitational and Geophysical Laboratory (MGGL) was established near Gyöngyösoroszi, Hungary in 2015, in the cavern system of an unused ore mine. The laboratory is located 88 m below the ...surface, with the aim of measuring and analysing the advantages of the underground installation's third generation gravitational wave detectors. Specialized instruments have been installed to measure seismic, infrasound and electromagnetic noise, and the variation of the cosmic muon flux. In the preliminary (RUN-0) test period, March-August 2016, data collection was accomplished. In this paper we describe the research potential of the MGGL, list the installed equipment and summarize the experimental results of RUN-0. Here we report on the RUN-0 data, that prepares the systematic and synchronized data collection of the next run period.
Summary of the long term data taking, related to one of the proposed next generation ground-based gravitational detector’s location is presented here. Results of seismic and infrasound noise, ...electromagnetic attenuation and cosmic muon radiation measurements are reported in the underground Matra Gravitational and Geophysical Laboratory near Gyöngyösoroszi, Hungary. The collected seismic data of more than two years is evaluated from the point of view of the Einstein Telescope, a proposed third generation underground gravitational wave observatory. Applying our results for the site selection will significantly improve the signal to noise ratio of the multi-messenger astrophysics era, especially at the low frequency regime.
The determination of the frequency response of a photoacoustic cell is a typical activity during design and adjustment of a photoacoustic setup. The most common method of such measurements is based ...on point-by-point checking of the amplitude of the photoacoustic signal at different modulation frequencies. Such an approach can be time-consuming, especially if a lot of measurements at low modulation frequencies are to be performed. The article presents a method based on investigation of a photoacoustic response to short square pulse stimulation instead of continuous modulation of the light source. The method allows for measurements of the frequency response to be substantially shortened. A theoretical description and properties of the pulse measurement method are discussed and illustrated with a comparison of experimental results obtained from both frequency response measurement methods.
Improved Photoacoustic Generator Borowski, T.; Burd, A.; Suchenek, M. ...
International journal of thermophysics,
12/2014, Letnik:
35, Številka:
12
Journal Article
Recenzirano
Odprti dostop
In conventional photoacoustic setups, the photoacoustic signal results from stimulation of a sample placed in the photoacoustic cell by the light modulated at a selected frequency. The signal can be ...amplified in a resonance photoacoustic cell. For this purpose, different types of acoustic resonators are used. Acoustic resonators are passive, frequency selective elements. An acoustic resonator used in a photoacoustic cell offers the opportunity to design a system working on a basis similar to that of a self-oscillating generator. The geometrical dimensions of an acoustic resonator, and the temperature, composition, and concentration of substances in the gas filling its interior determine the resonance frequency. In conventional photoacoustic setups, in which the resonance method is used, the variability of parameters requires continuous adjusting of or searching for the actual resonance frequency. Use of a fixed and arbitrary selected modulation frequency of the light beam can cause considerable errors in detection of substances in the sample or in determination of their concentration. Unlike conventional photoacoustic methods, the frequency of a photoacoustic signal in an improved photoacoustic generator is self-tuned to the actual resonant frequency of the photoacoustic cell. The improved photoacoustic generator operates without an external circuit that controls the optical modulator. The improved photoacoustic generator has been tested in different measurements of the concentration of methane in air. The automatic gain control signal can be used for determination of the absorption by the sample.
Expanding upon our prior work (Alhassan et al. 2022), where we evaluated the performance of single sub-detector data (SSDD) from the Einstein Telescope (ET) for binary black hole (BBH) detection ...using deep learning (DL). In this study, we explore the detection efficiency of BBHs using data combined from all three proposed sub-detectors of ET (TSDCD), employing five different lower frequency cutoffs (\(F_{\text{low}}\)): 5 Hz, 10 Hz, 15 Hz, 20 Hz, and 30 Hz, while maintaining the same match-filter Signal-to-Noise Ratio (\(MSNR\)) ranges as in our previous work: 4-5, 5-6, 6-7, 7-8, and >8. The Deep Residual Neural Network model (ResNet) was trained and evaluated for the detection of BBH gravitational wave signals using both TSDCD and SSDD. Compared to SSDD, the detection accuracy from TSDCD has shown substantial improvements, increasing from \(60\%\), \(60.5\%\), \(84.5\%\), \(94.5\%\) to \(78.5\%\), \(84\%\), \(99.5\%\), \(100\%\), and \(100\%\) for sources with \(MSNR\) of 4-5, 5-6, 6-7, 7-8, and >8, respectively. In a qualitative evaluation, the ResNet model detected sources at 86.601 Gpc, with an averaged \(MSNR\) of 3.9 (averaged across the three sub-detectors) and a chirp mass of 13.632 at 5 Hz. The results demonstrate a notable accuracy improvement for lower \(MSNR\) ranges (4-5, 5-6, 6-7) by \(18.5\%\), \(24.5\%\), and \(13\%\), respectively, and by \(5.5\%\) and \(1.5\%\) for higher \(MSNR\) ranges (7-8 and >8). TSDCD proves suitable for near-real-time detection and can benefit from a more powerful setup.
The European Physical Journal, Special Topics 228, 1693-1743
(2019) Summary of the long term data taking, related to one of the proposed next
generation ground-based gravitational detector's location ...is presented here.
Results of seismic and infrasound noise, electromagnetic attenuation and cosmic
muon radiation measurements are reported in the underground Matra Gravitational
and Geophysical Laboratory near Gy\"ongy\"osoroszi, Hungary. The collected
seismic data of more than two years is evaluated from the point of view of the
Einstein Telescope, a proposed third generation underground gravitational wave
observatory. Applying our results for the site selection will significantly
improve the signal to nose ratio of the multi-messenger astrophysics era,
especially at the low frequency regime.
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