Three autonomous HELYCON stations have been installed, calibrated and operated at the Hellenic Open University campus, detecting cosmic ray air showers. A software package for the detailed simulation ...of the detectors' response and the stations' operation has been developed. In this work we present the results of the analysis of the data collected by the stations during a period of one year and a half. The performance of the telescope is compared and found in very good agreement with the predictions of the simulation package. The angular resolution of each autonomous station is 3 to 5 degrees depending on the station geometry. In addition, by analyzing data from showers detected synchronously by more than one station, we evaluate the performance of the telescope in detecting very high energy (E > 5PeV) cosmic rays.
The expression of the GCN4 gene in yeast is regulated at the translational level: growth of yeast cells under amino acid starvation conditions results in an increase in the translational efficiency ...of GCN4 mRNA. A sequence within the 5′ untranslated region of this mRNA, which contains four small open reading frames, acts in cis to suppress translation when growth occurs in rich media. In this report, we have analyzed the effects on translation of a series of deletion, insertion, and substitution mutations in the 5′ untranslated region of GCN4 mRNA. This analysis showed that at least two distinct cis elements located within the region of the small upstream open reading frames are required, in conjunction with trans positive elements, for the translational activation of GCN4 mRNA. We propose that the translational efficiency of GCN4 mRNA is modulated by the rate of translation initiation at the upstream AUG codons.
High energy cosmic rays, with energies thousands of times higher than those encountered in particle accelerators, offer scientists the means of investigating the elementary properties of matter. In ...order to detect high energy cosmic rays, new detection hardware and experimental methods are being developed. In this work, we describe the network of HELYCON (HEllenic LYceum Cosmic Observatories Network) autonomous stations for the detection and directional reconstruction of Extended Atmospheric Showers (EAS) particle-fronts. HELYCON stations are hybrid stations consisting of three large plastic scintillators plus a CODALEMA antenna for the RF detection of EAS particle-fronts. We present the installation, operation and calibration of three HELYCON stations and the electronic components for the remote control, monitor and Data Acquisition. We report on the software package developed for the detailed simulation of the detectors' response and for the stations' operation. The simulation parameters have been fine tuned in order to accurately describe each individual detector's characteristics and the operation of each HELYCON station. Finally, the evaluation of the stations' performance in reconstructing the direction of the EAS particle-front is being presented.
High-energy cosmic rays are one of the primary sources of information for scientists investigating the elementary properties of matter. The need to study cosmic rays, with energies thousands of times ...larger than those encountered in particle accelerators, led to the development of modern detection hardware and experimental methodologies. We present a low power, low complexity data acquisition (DAQ) system with 100 ps resolution, suitable for particle and radiation detection experiments. The system uses a Multiple-Time-over-Threshold (MToT) technique for the treatment of the output signal of Photo Multiplier Tubes (PMTs). The use of three thresholds compensates for the slewing effects and offers a more accurate measurement of the PMT pulses' width. For the evaluation of the pulse the system uses comparators and a Time-to-Digital (TDC) converter, whereas the pulses are time-stamped using the GPS signal. The prototype card is analyzed for its noise behavior and is tested to verify its performance. The system has been designed for the HEllenic LYceum Cosmic Observatories Network (HELYCON) Extensive Air Showers (EAS) detector.
The spatial dependence of the timing performance of the R3809U-50 Micro-Channel-Plate PMT (MCP-PMT) by Hamamatsu was studied in high energy muon beams. Particle position information is provided by a ...GEM tracker telescope, while timing is measured relative to a second MCP-PMT, identical in construction. In the inner part of the circular active area (radius r\(<\)5.5\,mm) the time resolution of the two MCP-PMTs combined is better than 10~ps. The signal amplitude decreases in the outer region due to less light reaching the photocathode, resulting in a worse time resolution. The observed radial dependence is in quantitative agreement with a dedicated simulation. With this characterization, the suitability of MCP-PMTs as \(\text{t}_\text{0}\) reference detectors has been validated.
This document reports the first year of activity of the VBSCan COST Action network, as summarised by the talks and discussions happened during the VBSCan Thessaloniki 2018 workshop. The VBSCan COST ...action is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.
J.Phys.Conf.Ser. 39 (2006) 103-106 Magnetic field dependent transient solar observations are suggestive for
axion-photon oscillations with light axion(-like) particle involvement. Novel
dark-moon ...measurements with the SMART X-ray detectors can be conclusive for
radiatively decaying massive exotica like the generic solar Kaluza-Klein
axions. Furthermore, the predicted intrinsic strong solar magnetic fields could
be the reason of enhanced low energy axion production. Such an axion component
could be the as yet unknown origin of the strong quiet Sun X-ray luminosity at
energies below 1 keV. Solar axion telescopes should lower their threshold,
aiming to copy processes that might occur near the solar surface, be it due to
spontaneous or magnetically induced radiative decay of axion(-like) particles.
This is motivated also by the recent claim of an axion-like particle detection
by the laser experiment PVLAS.
Magnetic field dependent transient solar observations are suggestive for axion-photon oscillations with light axion(-like) particle involvement. Novel dark-moon measurements with the SMART X-ray ...detectors can be conclusive for radiatively decaying massive exotica like the generic solar Kaluza-Klein axions. Furthermore, the predicted intrinsic strong solar magnetic fields could be the reason of enhanced low energy axion production. Such an axion component could be the as yet unknown origin of the strong quiet Sun X-ray luminosity at energies below 1 keV. Solar axion telescopes should lower their threshold, aiming to copy processes that might occur near the solar surface, be it due to spontaneous or magnetically induced radiative decay of axion(-like) particles. This is motivated also by the recent claim of an axion-like particle detection by the laser experiment PVLAS.
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