The MEG II experiment is searching for new physics beyond the SM (e.g. SUSY-GUT, SUSY-seesaw) through the lepton flavor violating μ+→e+γ decay with ten times better sensitivity than the MEG ...experiment. The MEG collaboration published the result of B(μ+→e+γ)<4.2×10−13 at 90% C.L. in 2016, which was thirty times better result than the previous limit. As the sensitivity of the MEG experiment was already limited by the accidental background, the MEG detector had to be upgraded to reach one order of magnitude better sensitivity. The MEG experiment utilized 846 2 inch PMTs to detect scintillation light in a 900 l liquid xenon γ calorimeter. In the MEG II experiment, 216 2 inch PMTs on the γ incident face were replaced with 4092 MPPCs (SiPMs produced by Hamamatsu) to improve the energy and position resolutions. We started the detector commissioning with the full electronics readout channels for the first time in 2021, and soon after, we started the physics data taking. Here the LXe detector status including initial photon sensor calibration and performance will be summarized together with the expected detector performance. The PDE decrease of the SiPM observed in the high rate muon beam environment and our possible remedy will also be discussed.
Nowadays, wood bio-concrete (WBC) can be seen as an alternative to reduce environmental impacts of the construction industry. The behavior of this material under fire conditions, however, is still ...poorly understood. In this sense, this work aims to investigate the behavior of wood bio-concrete under fire conditions. In this study, the wood shavings content varied from 40 to 90 %. A Mass Loss Cone Calorimeter with an incident heat flux of 50 kW/m2 was used to analyze the combustion and reaction to fire of WBCs. Then, properties such as heat release rate, total heat released, total mass loss, mass loss rate, effective heat of combustion, time to ignition and temperature of ignition were evaluated. Thermogravimetric analysis (TG) and scanning electron microscopy (SEM) were used to better explain the results from the Cone Calorimeter tests. The results showed that the cementitious matrix promoted the protection of the wood and no ignition was observed for the materials studied, excepted when 90 % of shavings were used. The lower the density of the bio-concrete, the higher the values of combustion properties. This study confirmed that, under high heat flux conditions, most of the WBCs did not exhibit characteristics that promote ignition or flame propagation.
In this research, combustion behavior of agricultural residues known as miscanthus, poplar wood, and rice husk was investigated using thermal analysis techniques. Differential scanning calorimeter ...(DSC) and thermogravimetry (TG-DTG) techniques were used. Combustion experiments were performed at five different heating rates (5, 10, 15, 25, and 50°C/min). The reaction regions, ignition and burnout temperatures, heat flow rate values of biomass samples are determined. Activation energy of the biomass samples are calculated using three different iso-conversional methods. It is observed that all three agricultural residues show similar combustion characteristics. The results indicate that the reactivity of biomass fuels is due to the combustion of light compounds; however the energy release from biomass fuels is mainly due to the combustion of fixed carbon.
► Two distinct reactions were observed during biomass combustion. ► Ignition and burnout temperature of samples increased with increasing heating rate. ► Activation energy of the samples increased as ignition temperature increased.
The Tile Calorimeter (TileCal) is the central hadronic calorimeter of the ATLAS experiment at the Large Hadron Collider (LHC). It is made of steel plates acting as absorber and scintillating tiles as ...active medium. The TileCal response is calibrated to electromagnetic scale by means of several dedicated calibration systems. The accurate time calibration is important for the energy reconstruction, non-collision background removal as well as for specific physics analyses. The initial time calibration using so-called splash events and subsequent fine-tuning with collision data are presented. The monitoring of the time calibration with a laser system and physics collision data is discussed as well as the corrections for sudden changes performed before the recorded data are processed for physics analyses. Finally, the cell time resolution measured with jet events in Run 2 is presented.
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•Frequency range extension towards high and low frequencies of temperature modulated DSC.•Simple temperature-time profile consisting of temperature steps and isotherms.•Multi ...frequency analysis.•Applicable to chip and Calvet calorimeters.•Influence of the sample mass and general limitations are discussed.
Common temperature modulated DSCs are limited in the accessible frequency range to about 0.1–0.001Hz. We describe an extension of this frequency range towards lower and higher frequencies by using conventional DSCs (without TMDSC option). By applying steps in the temperature-time profile a simultaneous multi frequency analysis of the heating rate and the heat flow rate response yields heat capacity data over about 2 orders of magnitude in frequency from one single measurement. Based on this step response analysis we show on the example of a Calvet calorimeter, Setaram BT 2.15, an extension down to 10−5Hz and on the example of a chip calorimeter, Mettler Toledo Flash DSC 1, an extension up to 150Hz. Details of the experimental procedures are provided and the influence of sample size on the obtained data and general limitations, particularly regarding temperature assignment, are discussed. A relaxation map is used to combine all calorimetric data and to compare them with dielectric data.
Flammability of two kinds of two extruded polystyrene foam was tested by micro-scale combustion calorimeter and cone calorimeter. Maximum specific heat release rate, specific heat release, heat ...release temperature, combustion time and fire growth rates from micro-scale combustion calorimeter tests, and time to ignition, effective net heat of combustion, heat release rate from cone calorimeter tests, were used to compare the flammability of two foams. These two methods would draw different results in evaluating flammability of the foams. This confliction is due to the test scale and combustion condition. The relationship between these two methods can be established with ignition temperature; thus, micro-scale combustion calorimeter can be used to predict time to ignition in cone calorimeter tests. Joint using of micro-scale combustion calorimeter and cone calorimeter leads to a comprehensive evaluation of flammability of polymers.
•The joint study of the two additives, LiNO3 and Ca(NO3)2, present a working range between 132 and 571°C.•The synergistic effect between both additives shows a higher heat capacity of the individual ...proposed mixtures.•These mixtures would allow a direct use as storage material in parabolic trough solar power plants.
In this study, the effect of the addition of LiNO3 and/or Ca(NO3)2 to the solar salt NaNO3/KNO3, which is used as a storage material in CSP plants, on the physicochemical properties thereof was studied.
Thermal analyses were performed by differential scanning calorimetry (DSC), modulated differential scanning calorimetry (MDSC) and thermogravimetric analysis (TGA), obtaining the phase transitions, melting points, heat capacities and thermal stability of the materials studied. In addition, viscosity measurements were carried out at different temperatures close to the melting point of the salt mixtures to determine their flowability.
The study of these low-melting-point mixtures was executed through the synergistic effect exerted by a 30% LiNO3+60% KNO3+10% Ca(NO3)2 mixture, and it was observed that the addition of LiNO3 increases the thermal stability of the tested salts, whereas the addition of Ca(NO3)2 reduces the melting points and improves the economic cost of these mixtures
These mixtures were designed such that the melting point of the molten nitrates would be reduced, allowing for the mixtures’ direct use as storage materials in parabolic-trough solar power plants, therefore replacing the synthetic oil currently used as a heat transfer fluid (HTF) and heat exchanger oil. The use of these mixtures is intended to reduce the economic costs and improve the thermal storage of current solar technology.
