The use of accelerated beams of electrons, protons or ions has furthered the development of nearly every scientific discipline. However, high-energy muon beams of equivalent quality have not yet been ...delivered. Muon beams can be created through the decay of pions produced by the interaction of a proton beam with a target. Such 'tertiary' beams have much lower brightness than those created by accelerating electrons, protons or ions. High-brightness muon beams comparable to those produced by state-of-the-art electron, proton and ion accelerators could facilitate the study of lepton-antilepton collisions at extremely high energies and provide well characterized neutrino beams
. Such muon beams could be realized using ionization cooling, which has been proposed to increase muon-beam brightness
. Here we report the realization of ionization cooling, which was confirmed by the observation of an increased number of low-amplitude muons after passage of the muon beam through an absorber, as well as an increase in the corresponding phase-space density. The simulated performance of the ionization cooling system is consistent with the measured data, validating designs of the ionization cooling channel in which the cooling process is repeated to produce a substantial cooling effect
. The results presented here are an important step towards achieving the muon-beam quality required to search for phenomena at energy scales beyond the reach of the Large Hadron Collider at a facility of equivalent or reduced footprint
.
•Determination of the mass-dependent average prompt fission γ-ray multiplicity.•Confirmation of a saw-tooth like shape of multiplicity-mass correlation.•Detectors of various size and orientation ...relative to the fission-fragment detector.•High-statistics experimental data and proper treatment of instrument asymmetries.
Prompt γ rays from the spontaneous fission of 252Cf were measured with cerium-doped LaBr3 detectors. The average prompt fission γ-ray multiplicity, Mγ, was determined as a function of fragment mass number (A) and total kinetic energy (TKE). High-statistics data, obtained from three detectors of different size at different angles relative to the fission chamber, confirms unequivocally a saw-tooth like shape of the γ multiplicity as a function of fragment mass, in contrast to previously published data. In addition, the TKE-dependence of Mγ was determined experimentally and compared with recent data.
Although solvability conditions for a system of two linear equations are well-known even in the case of rings and, for three linear equations, in the case of matrices, in the case of four linear ...equations there are no results. In this paper, we consider systems of four linear matrix equations
,
and present some necessary and sufficient conditions for their solvability as well as an expression for the general solution. There are two advantages to our results: the presented solvability conditions in many cases can be presented in a purely algebraic form and the method used in the proof allows for a generalization of the obtained results to some more general structures such as algebras of bounded linear operators or rings, under some additional assumptions concerning regularity only. We present several applications of our results.
The aim of the presented study was to explore the influence of precise determination of sample matrix in order to obtain reliable gamma spectrometry results. The test was done using two different ...approaches which have the same goal: quantifying the activity concentration of uranium isotopes in different samples found in the former uranium ore deposit Mazdreja. The first approach is based on iterative methodology, which utilizes the characteristic of a sample that can be quantified before gamma spectrometric measurement. Density of the sample and calculated mass fractions of its constituents (which vary in each iteration) can help to obtain the efficiency function from which activity concentrations of 235U and 238U can be derived and corresponding masses of uranium for the next iteration. In this approach LabSOCS software is used in order to obtain appropriate efficiency. The second approach that was tested represents semiempirical method which applies Monte-Carlo simulations through Geant4 and EFFTRAN software codes for the purposes of generating the detection efficiency functions needed for further calculations.
The idea was to compare different methods for uranium activity concentration determination in sample matrices with high uranium mass content and also establish the need for precise calculation (described within the iterative method) by quantifying the relative deviation in activities, calculated by using different methods.
From the obtained results, it can be seen that it is very important to adjust the sample matrix to correct composition if we need a precise gamma spectrometry result. But if there is a need to get results in a short period of time, then for the estimation of the activity concentration of the analyzed sample an approximate sample composition can be used. All three tested analyzed methods gave comparable results inside 15% of difference. The major difference was obtained by EFFTRAN software, but on the other side this software is user-friendly and the results can be obtained faster than by using other analysis methods presented in this study.
•Testing the influence of precise determination of sample matrix.•The analyzed samples were from former uranium ore deposit Mazdreja.•One approach was Iteration method with LabSOCS software.•The second approach was GEANT4 and EFFTRAN software analysis.•Comparison of different methods for uranium activity concentration.
Presented study describes the optimization method of an HPGe detector through implementation of Geant4 toolkit. The optimized model was verified through comparison with experimentally obtained data ...using a set of point-like radioactive calibration sources. Acquired results displayed good agreement with the experimental data that falls under an average relative deviation of the order of ~ 2% within the energy range of 53–1836 keV. Additionally, in order to test the validity of the code it was also applied to a different detection equipment where an average relative deviation of the order of ~ 1.8% was achieved within the energy range of 121–1112 keV.
Background
Sarcopenia describes the age-associated loss of muscle mass, strength and function. The aim of this study was to compare the prevalence of sarcopenia in a cohort of community dwelling ...elderly people living in Berlin, Germany, according to the criteria proposed by current consensus statements and to study the respective impact on self-reported physical performance.
Material and methods
This study included 1405 participants from the Berlin aging study II (BASE-II). The appendicular skeletal muscle mass index (SMI) was assessed with dual energy X-ray absorptiometry (DXA), muscle strength was measured by hand grip strength and the timed up and go” test (TUG) was performed as a functional parameter to reflect mobility.
Results
The prevalence of sarcopenia was 24.3 % in terms of reduced SMI only and considerably lower for sarcopenia with reduced grip strength (4.1 %) and sarcopenia with limited mobility (2.4 %). Only 0.6 % of the participants fulfilled all three criteria. Of the subjects with a normal SMI, 8.6 % had reduced grip strength and 5.1 % had limited mobility, whereas 1.3 % subjects fulfilled both criteria. Participants with reduced strength or function reported severe difficulties in performing physical tasks significantly more often than participants with normal or reduced SMI alone (
p
<0.029–
p
<0.0001).
Conclusion
In BASE-II low skeletal muscle mass was much more frequent than reduced grip strength or poor function. Reduced strength and function were found to be associated with a greater impact on physical performance than reduced muscle mass. Low SMI does not seem to be a prerequisite for low strength or limitations in mobility.
•This paper presents an experimental investigation of the effect of jet velocity ratio.•Experiments for both single and two-phase flow were performed.•Both the primary jet and the lower secondary jet ...deviated from their geometric axes.•In a real furnace a large quantity of fuel will be directed close to the wall.•Such characteristics may contribute to substantial wall fouling.
The power generation industry throughout the world stands to gain significantly from process improvements and optimization which can potentially lead to cleaner production of cost effective electricity. The efficient operation of lignite-based tangentially-fired combustion systems, as commonly used in Victoria, Australia, depends on critical issues such as ignition and combustion of the fuel, which are largely controlled by burner aerodynamics. The geometry of the burner and the ratio of velocities between the primary and secondary jets play an important role in achieving stable combustion, high burnout of fuel, low production of pollutants and control of fouling. Slot-burners are vertically aligned stacks of rectangular nozzles delivering primary fuel and secondary air jets, and are commonly used in tangentially-fired boilers. To obtain a better understanding of the overall combustion process, it is important to understand the aerodynamics of jet development from these burners. This paper reports an experimental investigation into the aerodynamics of a recessed rectangular slot-burner of the type used in the Yallourn stage-2 tangentially-fired furnace. The 1:15 scale model burner consisted of a central (primary) rectangular fuel nozzle with two secondary rectangular air jets positioned above and below it. The burner jets were at an angle of 60° to the wall and were diffused and mixed in a recess before entering into the measurement vessel. A cross-flow jet was attached to the wall of the vessel to simulate the recirculation similar to tangentially-fired furnaces. Experiments for both single and two-phase flow were performed. For single-phase flow, the air flow was seeded with a fine mist of sugar particles (mean diameter 1μm) introduced into the primary, secondary and cross-flow ducts. For two-phase flow, solid glass spheres (mean diameter 66μm, density 2450kg/m3) were used as the representative of the coal particles and were introduced only at the centre of the primary duct from a bubbling fluidized bed. Experiments were conducted using a primary to cross-flow jet velocity ratio (φ) of 1.0 and secondary to primary jet velocity ratios (ϕ) of 1.0 and 3.0 as found in real furnaces. Laser Doppler Anemometry (LDA) was used to measure mean and turbulent velocity components in the near field and downstream regions of the jets. The flow pattern inside the recess was very complex and greatly influenced the flow where it entered the measurement vessel. For single-phase flow and ϕ=1.0, the jets diverged completely from the geometric axis of the burner and attached to the wall. The degree of deflection of the lower secondary jet was slightly more than the primary jet. For ϕ=3.0, after exiting from the nozzle, the primary jet diffused outwards and mixed with the higher momentum secondary jets in the recess and came out with the secondary jets. For two-phase flow and ϕ=1.0, in the mixing region between the primary and cross-flow jet, the gas-phase velocities were higher than the particle-phase. Further downstream the peak velocities of the particle-phase slightly deviated and occurred farther from the wall. For ϕ=3.0, downstream of the nozzle there was a tendency of separation for the gas-phase near the wall while the particle-phase was attached to the wall.
Performance of the MICE diagnostic system Bogomilov, M.; Tsenov, R.; Vankova-Kirilova, G. ...
Journal of instrumentation,
08/2021, Letnik:
16, Številka:
8
Journal Article
There is a well-known radon spa Niška Banja in south-east of Serbia. In Niška Banja spa there is a medical complex and radon is used for therapeutic purposes for many different diseases. This paper ...presents elevated radon levels in the Niška Banja spa. Indoor radon and radon in water activity concentration measurements in thermal pools and therapy rooms are presented. There are also results from gamma spectrometry measurements of soil, rock and therapy mud. A special attention is paid to the medical staff exposure to radon around thermal pools. The annual effective doses from radon for staff working around the thermal pools in Niška Banja spa are very high comparing to the maximum recommendation level. The maximal radon concentration of (22.90 ± 0.57) kBq m−3 was measured in the basement of the hotel-dispensary “Radon”. This hotel is settled on “bigar” rock – travertine, which has high content of 226Ra.
► Niška Banja was identified as a high natural radiation area. ► This area is very interesting from geological point of view. ► Indoor radon and radon in water concentration measurements from thermal pools and therapy rooms are presented. ► Gamma spectrometry measurements of soil samples are presented. ► Occupational doses for medical and non-medical staff who work around thermal pools are very high.
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