Applicability of our present setup for solar modulation studies in a shallow underground laboratory is tested on four prominent examples of Forbush decrease during solar cycle 24. Forbush decreases ...are of interest in space weather application and study of energy-dependent solar modulation, and they have been studied extensively. The characteristics of these events, as recorded by various neutron monitors and our detectors, were compared, and rigidity spectrum was found. Linear regression was performed to find power indices that correspond to each event. As expected, a steeper spectrum during more intense extreme solar events with strong X-flares shows a greater modulation of galactic cosmic rays. Presented comparative analysis illustrates the applicability of our setup for studies of solar modulation in the energy region exceeding the sensitivity of neutron monitors.
The background spectrum of a germanium detector, shielded from the radiations arriving from the lower and open for the radiations arriving from the upper hemisphere, is studied by means of absorption ...measurements, both in a ground level and in an underground laboratory. The low-energy continuous portion of this background spectrum that peaks at around 100keV, which is its most intense component, is found to be of very similar shape at the two locations. It is established that it is mostly due to the radiations of the real continuous spectrum, which is quite similar to the instrumental one. The intensity of this radiation is in our cases estimated to about 8000 photons/(m2s·2π·srad) in the ground level laboratory, and to about 5000 photons/(m2s·2π·srad) in the underground laboratory, at the depth of 25m.w.e. Simulations by GEANT4 and CORSIKA demonstrate that this radiation is predominantly of terrestrial origin, due to environmental gamma radiations scattered off the materials that surround the detector (the “skyshine radiation”), and to a far less extent to cosmic rays of degraded energy.
•We studied the low-energy part of continuous background spectra of germanium detectors.•The study was performed at the ground level and at the shallow underground sites.•The instrumental spectrum is due to radiations of the similar continuous spectrum.•The low-energy radiation is of both terrestrial and cosmic-ray origin.•In our study, we find that this radiation is of predominantly terrestrial origin.
In this study, several multivariate methods were used for forecasting hourly PM
10
concentrations at four locations based on SO
2
and meteorological data from the previous period. According to the ...results, boosted decision trees and multi-layer perceptrons yielded the best predictions. The forecasting performances were similar for all examined locations, despite the additional PM
10
spatio-temporal analysis showed that the sites were affected by different emission sources, topographic and microclimatic conditions. The best prediction of PM
10
concentrations was obtained for industrial sites, probably due to the simplicity and regularity of dominant pollutant emissions on a daily basis. Conversely, somewhat weaker forecast accuracy was achieved at urban canyon avenue, which can be attributed to the specific urban morphology and most diverse emission sources. In conclusion to this, the integration of advanced multivariate methods in air quality forecasting systems could enhance accuracy and provide the basis for efficient decision-making in environmental regulatory management.
Radon time-series analysis, based on the short-term indoor radon measurements performed worldwide, shows two main periodicity: daily and seasonal. The information obtained from time series of the ...measured radon values is the results of the complex radon dynamics that arises from the influence of the large number of different parameters (the state of the indoor atmosphere (temperature, pressure and relative humidity, aerosol concentration), the exchange rate between indoor and outdoor air and so on). In this paper we considered daily radon variability in the underground low-background laboratory in Belgrade, Serbia. The results are originated from the radon time-series analysis based on the 3 y of the continuous short-term indoor radon measurements. At the same time, we obtained the time series of the temperature, pressure and relative humidity in the laboratory. We also tried to find the correlation between different time series.
Performance of the CMS ECAL safety system for Super Modules SM0 and SM1 Milenovic, P.; Puzovic, J.; Jovanovic, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2005, Letnik:
554, Številka:
1
Journal Article
Recenzirano
A prototype of the safety system for the electromagnetic calorimeter (ECAL) of the CMS detector at LHC has been implemented and tested in Super Modules SM0 and SM1 during the ECAL test-beam campaign ...in summer 2003. The aim was to examine the system performance thoroughly and to resolve several open issues regarding the final system design. The performed tests mainly focused on the readout system performance, its calibration and noise problems. Furthermore, irradiation tests of the readout electronics components with a 64
MeV proton beam up to an equivalent cumulative dose of 200
kGy and 3.2×10
14 neutron
cm
−2 have been performed at the Paul Scherrer Institute in spring 2004. The results of all these tests are very promising, leading to the conclusion that the tested prototype offers an excellent basis for the development of the safety system for the entire CMS ECAL.
Power transformer modelling and simulation requires detailed material and design information. However, this detailed information about a transformer is usually not entirely available. Therefore, we ...use a supplemental single-phase excitation setup (saturation test) to measure the transformer core hysteresis characteristic at elevate voltages. Only transformer parameters from the factory acceptance test and very few design data is used to set up the topology transformer models. In topology-correct models each section of the core is represented separately. Also the different off-core (leakage) flux paths can be included in the models. In this study we compare two transformer topology models in the electric domain with measurements from a 3-limb 2-winding, 50 kVA transformer in YNyn0 vector group. The first model uses the capacitance-permeance analogy to model the transformer. The second model uses the principle of duality of electric and magnetic circuits together with the Jiles-Atherton (JA) model for the hysteresis implementation. The hysteresis model parameters in both models are identified with the Nelder-Mead Simplex algorithm. We have found that both transformer topology models can reproduce the measured current waveforms during the no-load and saturation test with very good accuracy. The active and reactive power deviation between the capacitor-permeance model and the measurements are below 10 %, and for the JA model below 17 % for the no-load and the saturation test.
We review the potential of plasma medical applications, the connections to
nanotechnologies and the results obtained by our group. A special issue in
plasma medicine is the development of the plasma ...sources that would achieve
non-equilibrium at atmospheric pressure in atmospheric gas mixture with no or
only marginal heating of the gas, and with desired properties and mechanisms
that may be controlled. Our studies have shown that control of radicals or
chemically active products of the discharge such as ROS (reactive oxygen
species) and/or NO may be used to control the growth of the seeds. At the
same time specially designed plasma needle and other sources were shown to be
efficient to sterilize not only colonies of bacteria but also planctonic
samples (microorganisms protected by water) or bio films. Finally we have
shown that plasma may induce differentiation of stem cells. Non-equilibrium
plasmas may be used in detection of different specific markers in medicine.
For example proton transfer mass spectroscopy may be employed in detection of
volatile organic compounds without their dissociation and thus as a technique
for instantaneous measurement of the presence of markers for numerous
diseases.
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