Calorimeter Response Research Articles

Direct determination of anaerobe contributions to the energy metabolism of Trypanosoma cruzi by chip calorimetry.

We describe a chip calorimetric technique that allows the investigation of biological material under anoxic conditions in a micro-scale and in real time. Due to the fast oxygen exchange through the sample flow channel wall, the oxygen concentration inside the samples could be switched between atmospheric oxygen partial pressure to an oxygen concentration of 0.5% within less than 2h. Using this technique, anaerobic processes in the energy metabolism of Trypanosoma cruzi could be studied directly. The comparison of the calorimetric and respirometric response of T. cruzi cells to the treatment with the mitochondrial inhibitors oligomycin and antimycin A and the uncoupler FCCP revealed that the respiration-related heat rate is superimposed by strong anaerobic contributions. Calorimetric measurements under anoxic conditions and with glycolytic inhibitors showed that anaerobic metabolic processes contribute from 30 to 40% to the overall heat production rate. Similar basal and antimycin A heat rates with cells under anoxic conditions indicated that the glycolytic rates are independent of the oxygen concentration which confirms the absence of the "Pasteur effect" in Trypanosomes. Graphical abstract.

Performance of the Muon g−2 calorimeter and readout systems measured with test beam data

A single calorimeter station for the Muon $g-2$ experiment at Fermilab includes the following subsystems: a 54-element array of PbF$_{2}$ Cherenkov crystals read out by large-area SiPMs, bias and slow-control electronics, a suite of 800 MSPS waveform digitizers, a clock and control distribution network, a gain calibration and monitoring system, and a GPU-based frontend read out through a MIDAS data acquisition environment. The entire system performance was evaluated using 2.5 - 5 GeV electrons at the End Station Test Beam at SLAC. This paper includes a description of the individual subsystems and the results of measurements of the energy response and resolution, energy-scale stability, timing resolution, and spatial uniformity. All measured performances meet or exceed the $g-2$ experimental requirements. Based on the success of the tests, the complete production of the required 24 calorimeter stations has been made and installation into the main experiment is complete. Furthermore, the calorimeter response measurements determined here informed the design of the reconstruction algorithms that are now employed in the running $g-2$ experiment.

Analysis of testbeam data of the highly granular RPC-steel CALICE digital hadron calorimeter and validation of Geant4 Monte Carlo models

We present a study of the response of the highly granular Digital Hadronic Calorimeter with steel absorbers, the Fe-DHCAL, to positrons, muons, and pions with momenta ranging from 2 to 60 GeV/c. Developed in the context of the CALICE collaboration, this hadron calorimeter utilises Resistive Plate Chambers as active media, interspersed with steel absorber plates. With a transverse granularity of $1\,\times\,1\,$cm$^{2}$ and a longitudinal segmentation of 38 layers, the calorimeter counted 350,208 readout channels, each read out with single-bit resolution (digital readout). The data were recorded in the Fermilab test beam in 2010-11. The analysis includes measurements of the calorimeter response and the energy resolution to positrons and muons, as well as detailed studies of various shower shape quantities. The results are compared to simulations based on Geant4, which utilise different electromagnetic and hadronic physics lists.

Effect of Surface Modification on the Glass Transition Dynamics of Highly Polar Molecular Liquid S-Methoxy-PC Confined in Anodic Aluminum Oxide Nanopores

In the presence of nanoscale confinement, the role of surface effects come to the fore in determining the glass-transition dynamics of the molecular liquids and polymers. Therefore, by playing with the surface chemistry it is possible to understand better the mechanism which governs the behavior of glass-forming systems at the nanoscale. In this work, we have combined dielectric and calorimetric data to study surface and confinement effects for highly polar glass-forming liquid S-Methoxy-PC constrained within anodic aluminum oxide membranes of different pore sizes. The inner surface of the pores was modified either by silanization or atomic layer deposition (ALD) coatings. For the tested substance in native nanopores, we have observed two glass transition events in the calorimetric response accompanied by a characteristic deviation of the temperature dependence of the α-relaxation time from the Vogel–Fulcher–Tamman law. We found that depending on the hydrophobicity of the ALD layer the glass transition temperature of the interfacial layer tends to decrease, the α-relaxation peak broadens, and the molecular mobility slows down compared to the native pores. These changes are more visible with increasing hydrophobicity of the surface. Silanization was also found to eliminate at least partially the effects caused by nanopore confinement. However, in this study the most pronounced effects were observed only for pores with large diameters.

Studies of granularity of a hadronic calorimeter for tens-of-TeV jets at a 100 TeV pp collider

Jet substructure variables for hadronic jets with transverse momenta in the range from 2.5 TeV to 20 TeV were studied using several designs for the spatial size of calorimeter cells. The studies used the full Geant4 simulation of calorimeter response combined with realistic reconstruction of calorimeter clusters. In most cases, the results indicate that the performance of jet-substructure reconstruction improves with reducing cell size of a hadronic calorimeter from Δ η × Δ ϕ = 0.087×0.087, which are similar to the cell sizes of the calorimeters of LHC experiments, by a factor of four, to 0.022×0.022.

Effects of Strain Path Changes on the Kinematics and the Intrinsic Dissipation Accompanying PLC Bands in Al-Mg Alloys

Plastic instabilities, such as the Portevin-Le Chatelier (PLC) effect, reduce material ductility and induce surface roughness during sheet metal forming. The formation and propagation of PLC bands have been extensively studied by using the uniaxial tension test. However, this strain state differs from the complex strain paths encountered in most metal forming operations. In this work, the linear and non-linear strain path effects on the kinematics of PLC instabilities are investigated in an AA5086-H111 Al-Mg alloy, at strain rates between 0.1 and 0.5 s− 1. This is the first study on the spatio-temporal distribution analysis of heat produced by PLC bands during non-linear loadings. Non-linear strain paths are generated with an innovative one-step procedure, without unloading. The strain path changes are controlled by the displacements along the two perpendicular directions of a cruciform specimen loaded with a planar biaxial tensile device. For a given linear or non-linear strain path, full kinematic and thermal fields on the specimen surface were characterized by using Digital Image Correlation (DIC) and infrared thermography (IRT). Heat source fields were reconstructed from the temperature fields and the heat diffusion equation. The calorimetric response, which mainly corresponds to the intrinsic dissipation produced by the material, permits the kinematics of PLC bands to be investigated. It is shown that the strain state (uniaxial, plane strain or equibiaxial) strongly affects the formation and propagation of such plastic instabilities. For each strain path, a band typology is clearly identified. For two-step non-linear strain paths, the change in the strain state induces an instantaneous modification of the kinematics. The band kinematics is directly linked to the current strain path and the plastic deformation history does not appear to influence the typology of bands.

Simulation of the CMS electromagnetic calorimeter response at the energy and intensity frontier

The electromagnetic calorimeter (ECAL) of the CMS experiment at the LHC is a homogeneous calorimeter made of 75848 lead tungstate (PbWO4) scintillating crystals, designed for high precision electron and photon energy measurements in hadron collisions at the TeV scale. The detailed simulation of the calorimeter response is crucial for physics analyses involving electrons, photons, jets or missing energy. The detector simulation has been tuned during the first LHC run, including a detailed description of the upstream material. The increase of centre-of-mass energy, bunch crossing rate and instantaneous luminosity in the second run has resulted in updated and improved data readout, settings and reconstruction techniques. Furthermore, aging effects due to radiation, in particular increases in noise in the photodetectors and crystal transparency losses, have caused a change of the calorimeter response. All of these effects have been taken into account in order to improve the simulation of the calorimeter response and to ensure that it describes the data well over time, notwithstanding the evolving conditions. In 2024 the ECAL will undergo an upgrade to cope with the high luminosity phase of the LHC (HL-LHC). The temperature of the calorimeter will be lowered to mitigate the aging effects, the front-end electronics will be replaced with a faster version and the data will be read out in streaming mode towards the off-detector electronics. The fast PbWO4 response time will be exploited to measure the timing of high-energy showers with high precision. A detailed simulation description of the crystal response is fundamental for the design of the detector electronics and to predict the performance for the energy and timing measurements. The techniques employed in tuning the simulation of the detector response for the present running conditions and for the upgrade will be presented.

Investigation of the electromagnetic calorimeter response function by cosmic muons

In this work, the passage of cosmic muons in calorimetric modules was simulated. The coefficients for converting signal amplitudes into absorbed energy of a passing particle were obtained. The data collected during the exposure of the electromagnetic calorimeter to cosmic muons were analyzed. The results of the analysis were used to process the experimental data obtained in the interaction of carbon, argon and krypton at 3.5 GeV/nucleon energy with different targets.

Energy loss measurements of inclined muon bundles in the Cherenkov water detector

An experiment on the measurements of the energy deposit of inclined cosmic ray muon bundles is being conducted at the experimental complex NEVOD (MEPhI). The complex includes the Cherenkov water calorimeter with a volume of 2000 m3 and the coordinate-tracking detector DECOR with a total area of 70 m2. The DECOR data are used to determine the local muon densities in the bundle events and their arrival directions, while the energy deposits (and hence the average muon energy loss) are evaluated from the Cherenkov calorimeter response. Average energy loss carries information about the mean muon energy in the bundles. The detection of the bundles in a wide range of muon multiplicities and zenith angles gives the opportunity to explore the energy range of primary cosmic ray particles from about 10 to 1000 PeV in the frame of a single experiment with a relatively small compact setup. Experimental results on the dependence of the muon bundle energy deposit on the zenith angle and the local muon density are presented and compared with expectations based on simulations of the EAS muon component with the CORSIKA code.

Effect of sodium carbonate/sodium silicate activator on the rheology, geopolymerization and strength of fly ash/slag geopolymer pastes

Reactions between the fly ash/slag composite mix and the Na2CO3/Na2SiO3 activator were monitored through Isothermal conduction calorimetry. The resulting products were analyzed with the help of XRF, XRD and FT-IR techniques. In calorimetric response, the composite pastes had more total heat release than the fly ash paste requiring ∼50% less activation energy to yield reaction products. These products were largely amorphous as observed in the XRD patterns. Rheological studies indicated that composite pastes were very stiff above 25 wt% slag addition as its yield stress was almost doubled to fly ash paste. The compressive strength of hardened pastes increased with increasing slag content and activator dosage and decreased with increasing water-binder ratio. The deposition of reaction products onto the fly ash/slag particle surfaces and also the dense microstructures as observed in FESEM supported higher strength of geopolymer pastes at higher activator and slag contents. The developed paste with standard sand at 1:2 ratio produced mortar with a compressive strength of ∼72 MPa.

Operation and performance of the ATLAS Tile Calorimeter in Run\xa01

The Tile Calorimeter is the hadron calorimeter covering the central region of the ATLAS experiment at the Large Hadron Collider. Approximately 10,000 photomultipliers collect light from scintillating tiles acting as the active material sandwiched between slabs of steel absorber. This paper gives an overview of the calorimeter’s performance during the years 2008–2012 using cosmic-ray muon events and proton–proton collision data at centre-of-mass energies of 7 and 8 TeV with a total integrated luminosity of nearly 30 fb^{-1}. The signal reconstruction methods, calibration systems as well as the detector operation status are presented. The energy and time calibration methods performed excellently, resulting in good stability of the calorimeter response under varying conditions during the LHC Run 1. Finally, the Tile Calorimeter response to isolated muons and hadrons as well as to jets from proton–proton collisions is presented. The results demonstrate excellent performance in accord with specifications mentioned in the Technical Design Report.

Measuring the Cherenkov light yield from cosmic ray muon bundles in the water detector

Abstract An experiment on the measurements of the Cherenkov light yield from inclined cosmic ray muon bundles in water is being conducted at the Experimental complex NEVOD (MEPhI). The total number of Cherenkov photons is nearly proportional to the muon energy deposit (including secondary particles produced by muons and cascades from them) within the detector volume. Since at muon energies above a hundred GeV the energy loss is almost linearly related to the energy of muons, the average energy loss of the bundles carries information about the mean muon energy in such events. The complex includes the Cherenkov water calorimeter NEVOD with a volume of 2000 m3 and the coordinate-tracking detector DECOR with a total area of 70 m2. DECOR data are used to determine the local muon densities in the bundle events and their arrival directions, while the energy deposits are evaluated from the Cherenkov calorimeter response. The detection of the bundles in a wide range of muon multiplicities and zenith angles gives the opportunity to explore the energy range of primary cosmic ray particles from about 10 PeV to 1000 PeV and even higher in frame of a single experiment. Experimental results on the dependence of the muon bundle energy deposit on the zenith angle and the local muon density are presented and compared with expectations based on simulation of the EAS muon component by means of the CORSIKA code.

Mapping of calorimetric response for the geopolymerisation of mechanically activated fly ash

The focus of this paper is on isothermal conduction calorimetric study of the geopolymerisation of mechanically activated fly ash. Mechanical activation was carried out in an eccentric vibratory mill due to its high efficiency. The samples used for calorimetry were characterised in terms of particle size distribution (by laser diffraction), morphology and chemical heterogeneity (by SEM–EDS) and structure (XRD and FTIR). The calorimetric response, rate of heat evolved ( $$\dot{q}$$ ) with geopolymerisation time (t), was collected for 24 h. The 7 × 7 calorimetric maps were prepared using the data at seven reaction temperatures (TGP = 27, 32, 37, 42, 47, 53, 60 °C) for seven samples obtained after different duration of milling (tMA = 0, 5, 15, 30, 60, 90, 120 min). Comprehensive profiling of fly ash reactivity was done in terms of the maps for rate of heat evolved ( $$\dot{q}$$ vs. time), total heat evolved (Q vs. time), fraction reacted (α vs. time) and iso-conversion time (tα). Each of the mechanically activated samples behaved uniquely. A model-free approach based on ‘iso-conversional methods’ was deployed to analyse the kinetics of geopolymerisation. The analysis revealed that activation energy changes with fraction reacted and displays three regimes of dependence. The merit of the model-free analysis over traditionally used ‘model-based analysis’ is emphasised. Further, in the context of geopolymerisation, empirical parameters based on fraction reacted are used to delineate efficacy of mechanical activation vis-a-vis reaction temperature.

Regression Analysis for Nucleation-Elongation Model of Supramolecular Assembly: How To Determine Nucleus Size.

Nucleation-elongation is known to give satisfactory descriptions of many supramolecular polymerization systems in thermal equilibrium. Its key feature is the necessity to form a "nucleus" consisting of a certain number of monomer units before being able to grow into a longer polymer chain. The size of the nucleus has significant implications for the understanding of the supramolecular polymerization mechanism. Here we investigate how experiments can give information on the nucleus size by regression analysis of various types of measurements. The measurements of free monomer concentrations, diffusion coefficients, and calorimetric response as functions of concentration or temperature are considered. The nucleation-elongation model with a general value for the nucleus size is used to provide mathematical expressions for these experimental observables. Numerical experiments are performed where experimental errors are simulated by computer-generated random numbers, and it is investigated whether least-squares fitting analyses can give the correct values of the nucleus size in the presence of experimental errors. It is recommended that the calorimetric measurements such as differential scanning calorimetry (DSC) or isothermal titration calorimetry (ITC) be performed under various conditions to correctly determine the nucleus size experimentally.

Use of Large-Area Photodiodes for Improving the Characteristics of an Electromagnetic Calorimeter Based on Lead Tungstate Crystals

It is shown that an increase in the area of photodetectors allows the PHOS electromagnetic calorimeter of the ALICE experiment to operate at room temperature with better spectrometric characteristics. The linearity of the calorimeter response has been investigated in the 1–110 GeV energy range using both Hamamatsu S8664-1010 avalanche photodiodes with a large area (10 × 10 mm2) and arrays of MPPC Hamamatsu S12572-015C silicon photomultipliers with a sensitive area of 6 × 6 mm2. The calorimeter based on avalanche photodiodes is linear in the energy range under investigation compared to a calorimeter composed of silicon-photomultiplier arrays.

ATLAS Tile Calorimeter Calibration and Monitoring Systems

The ATLAS Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment at LHC. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibers to photo-multiplier tubes (PMTs), located in the outer part of the calorimeter. The readout is segmented into about 5000 cells, each one being read out by two PMTs in parallel. To calibrate and monitor the stability and performance of the full readout chain during the data taking, a set of calibration sub-systems is used. The TileCal calibration system comprises Cesium radioactive sources, laser, charge injection elements, and an integrator based readout system. Combined information from all systems allows to monitor and to equalize the calorimeter response at each stage of the signal evolution, from scintillation light to digitization. Calibration runs are monitored from a data quality perspective and used as a crosscheck for physics runs. Data quality in physics runs is monitored extensively and continuously. Any problems are reported and immediately investigated. The data quality efficiency achieved was 99.6% in 2012, 100% in 2015, 98.9% in 2016 and 99.4% in 2017. Based on LHC Run-I experience, all calibration systems were improved for Run-II. TileCal performance during LHC Run-II, (2015-2017), is discussed, including calibration, stability, absolute energy scale, uniformity and time resolution. Results show that the TileCal performance is within the design requirements and has given essential contribution to reconstructed objects and physics results.

Effect of different functionalized carbon nanostructures as fillers on the physical properties of biocompatible poly(l-lactic acid) composites

Composites of carbon nanostructures (CNSs) and biocompatible polymers are promising materials for a series of advanced technological applications, ranging from biomedicine and bioelectronics to smart packaging and soft robotics. In this work, we present three types of organic-functionalized CNSs, namely p-methoxyphenyl functionalized multi-walled carbon nanotubes, carbon nanohorns and reduced graphene oxide, used as nanofillers for the preparation of homogeneous and well-dispersed composites of poly(l-lactic acid), a biocompatible and biodegradable FDA-approved polymer. A thorough characterization of the composites is given in terms of calorimetric response, electrical and mechanical properties. Significant differences are observed among the different types of CNS nanofillers, underlying the key role played by the nanoscale shape and distribution of the components in driving the macroscopic behavior of the composite material. Surface properties are probed through advanced atomic force microscopy techniques, on both flat substrates (films) and confined systems (nanofibers). All these composites proved to be biocompatible and to support as scaffolds the proliferation of human neuronal precursor cell line SH-SY5Y, opening the route to a future comparative analysis on their ability to boost neuronal differentiation.

Calibration and performance of the ATLAS Tile Calorimeter during the LHC Run 2

The Tile Calorimeter (TileCal) is the hadronic sampling calorimeter of the ATLAS experiment at the Large Hadron Collider (LHC). TileCal uses iron absorbers and scintillators as active material and it covers the central region | η| < 1.7. Jointly with the other sub-detectors it is designed for measurements of hadrons, jets, tau-particles and missing transverse energy. It also assists in muon identification. TileCal is regularly monitored and calibrated by several different calibration systems: a Cs radioactive source, a laser light system to check the PMT response, and a charge injection system (CIS) to check the front-end electronics. These calibration systems, in conjunction with data collected during proton-proton collisions, Minimum Bias (MB) events, provide extensive monitoring of the instrument and a means for equalizing the calorimeter response at each stage of the signal propagation. The performance of the calorimeter has been established with cosmic ray muons and the large sample of the proton-proton collisions and compared to Monte Carlo (MC) simulations. The response of high momentum isolated muons is also used to study the energy response at the electromagnetic scale, isolated hadrons are used as a probe of the hadronic response. The calorimeter time resolution is studied with multijet events. A description of the different TileCal calibration systems and the results on the calorimeter performance during the LHC Run 2 are presented. The results on the pile-up noise and response uniformity studies are also discussed.

Functional Performances of CuZnAl Shape Memory Alloy Open-Cell Foams

Shape memory alloys (SMAs) with cellular structure offer a unique mixture of thermo-physical–mechanical properties. These characteristics can be tuned by changing the pore size and make the shape memory metallic foams very attractive for developing new devices for structural and functional applications. In this work, CuZnAl SMA foams were produced through the liquid infiltration of space holder method. In comparison, a conventional CuZn brass alloy was foamed trough the same method. Functional performances were studied on both bulk and foamed SMA specimens. Calorimetric response shows similar martensitic transformation (MT) below 0 °C. Compressive response of CuZnAl revealed that mechanical behavior is strongly affected by sample morphology and that damping capacity of metallic foam is increased above the MT temperatures. The shape memory effect was detected in the CuZnAl foams. The conventional brass shows a compressive response similar to that of the martensitic CuZnAl, in which plastic deformation accumulation occurs up to the cellular structure densification after few thermal cycles.

Influence of water and aluminium powder content on the properties of waste-containing geopolymer foams

The production of low thermal conductivity geopolymers has attracted increasing attention over the past years due to their low cost and green processing technology. In this work, light and porous geopolymers were produced by the proper association of aluminium content and solid-to-liquid ratio. This allowed the production of very low thermal conductivity geopolymers (78.6mW/mK) exhibiting homogeneous pore size distribution which suggests their use in thermal insulating applications. Moreover this study also reduced the existing knowledge gap concerning the fresh-state characterization of foamed geopolymer slurries. The influence of aluminium powder, curing temperature and solid-to-liquid ratio on the calorimetric response of biomass fly ash-containing geopolymer slurries was evaluated. The calorimetric response of geopolymer slurries shows that the time needed to reach the maximum temperature decreases when the aluminium powder rises, thus shortening the open time before in situ application. It was also found that the geopolymerization rate is governed by the curing temperature.