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Calibration of titration calorimeters is an ongoing problem, particularly with calorimeters with reaction vessel volumes < 10 mL in which an electrical calibration heater is positioned outside the calorimetric vessel. Consequently, a chemical reaction with a known enthalpy change must be used to accurately calibrate these calorimeters. This work proposes the use of standard solutions of potassium acid phthalate (KHP) titrated into solutions of excess sodium hydroxide (NaOH) or excess tris(hydroxymethyl)aminomethane (TRIS) as standard reactions to determine the collective accuracy of the relevant variables in a determination of the molar enthalpy change for a reaction. KHP is readily available in high purity, weighable for easy preparation of solutions with accurately known concentrations, stable in solution, not compromised by side reactions with common contaminants such as atmospheric CO2, and non-corrosive to materials used in calorimeter construction. Molar enthalpy changes for these reactions were calculated from 0 to 60 °C from reliable literature data for the pKa of KHP, the molar enthalpy change for protonation of TRIS, and the molar enthalpy change for ionization of water. The feasibility of using these reactions as enthalpic standards was tested in several calorimeters; a 50 mL CSC 4300, a 185 μL NanoITC, a 1.4 mL VP-ITC, and a TAM III with 1 mL reaction vessels. The results from the 50 mL CSC 4300, which was accurately calibrated with an electric heater, verified the accuracy of the calculated standard values for the molar enthalpy changes of the proposed reactions. [ABSTRACT FROM AUTHOR]

This study investigates the suitability of heat conduction calorimeters for determining the specific heat capacity of solid and liquid substances. Accurate and precise measurements were obtained for various substances, including water, ethylene glycol, the ionic liquid [EMIM][TCM], and copper, with relative standard deviations averaging less than 1%. Measurements on [EMIM][DCA] indicated a systematic deviation from the literature values. The study highlights the repeatability of the measurement method, which worked well for both temperature increases and decreases, as well as for the mean of the two. The influence of sample size on the results when it came to liquids was also investigated, revealing that large sample sizes led to underpredictions; while, small sizes yielded the opposite effect. The best results were obtained with half-filled vials; a similar filling level as was used in the electrical calibrations of the calorimeters with heaters in the vials. Additionally, no significant differences were observed among the eight calorimeters of the I-Cal Flex instrument, and different baseline calculation methods had negligible impact on the results. Overall, this study illustrates how a heat conduction calorimeter can be utilized for accurate and precise heat capacity measurements for both solid and liquid substances. [ABSTRACT FROM AUTHOR]

Calorimetric experiments in space of the current and of the next generation measure cosmic rays directly above TeV on satellites in low Earth orbit. A common issue of these detectors is the determination of the absolute energy scale for hadronic showers above TeV. In this work, we propose the use of the Moon–Earth spectrometer technique for the calibration of calorimeters in space. In brief, the presence of the Moon creates a detectable lack of particles in the detected cosmic ray arrival directions. The position of this depletion has an offset with respect to the Moon center due to the deflection effect of the geomagnetic field on the cosmic rays that depends on the energy and the charge of the particle. The developed simulation will explore if, with enough statistics, angular, and energy resolutions, this effect can be exploited for the energy scale calibration of calorimeters on satellites in orbit in Earth's proximity. [ABSTRACT FROM AUTHOR]

In vivo determination of the skin's thermal properties is of growing interest. Several types of sensors are being designed and tested. In this field, we have developed a skin calorimeter for the determination of the heat flow, the heat capacity and the thermal resistance of the skin. The calorimeter calibration consists of the determination of the parameters of the model we have chosen to represent the behavior of the device. This model considers the heat capacity and the thermal resistance of the skin, which depend on the case (body zone, subject, physical state, etc.) and also have a strong time dependence. Therefore, this work includes a validation study with reference materials. Finally, it is concluded that the heat capacity determined is a function of the thermal penetration depth of the measurement characteristics. In the case of high thermal conductivity materials in which the thermal penetration is nearly total, the heat capacity obtained coincides with that of the reference material sample. [ABSTRACT FROM AUTHOR]

Traceability for power measurements at high millimeter-wave and terahertz frequencies presents significant challenges since traditional waveguide micro-calorimetry systems are only readily available at frequencies up to 110 GHz. There are, however, different types of commercially available power meters which operate at frequencies above 110 GHz, where a lack of traceability means the accuracy and associated uncertainty of measurements using these power meters is not well understood. This paper describes the characterisation and traceable calibration of a commercially available waveguide power meter (VDI Erickson PM5) which is designed to operate from 75 GHz to 3 THz, using appropriate waveguide tapers. This includes an assessment of the overall system performance along with an evaluation of the uncertainty in measurements made using the system. The assessment is carried out at W-band (75 to 110 GHz) by comparison with micro-calorimeter systems which are used as primary standard power measurement systems at these frequencies. [ABSTRACT FROM AUTHOR]

The nonlinear energy response of cryogenic microcalorimeters is usually corrected through an empirical calibration. X-ray or gamma-ray emission lines of known shape and energy anchor a smooth function that generalizes the calibration data and converts detector measurements to energies. We argue that this function should be an approximating spline. The theory of Gaussian process regression makes a case for this functional form. It also provides an important benefit previously absent from our calibration method: a quantitative uncertainty estimate for the calibrated energies, with lower uncertainty near the best-constrained calibration points. [ABSTRACT FROM AUTHOR]

Twenty-five years ago, at the CALOR1997 conference in Tucson, the idea of dual-readout calorimetry was first presented. In this talk, I discuss the considerations that led to that proposal, and describe the developments that have since taken place, to the point where dual-readout calorimetry is now considered a major candidate for experiments at future colliders. [ABSTRACT FROM AUTHOR]

This article reviews the work to date on the CALOrimeter with Radial thermal transfers for nuclear REactors (CALORRE) differential calorimeter patented by Aix-Marseille University (AMU) and the French Alternative Energies and Atomic Energy Commission (CEA) in 2015. The article presents the results obtained with the first prototype of the CALORRE calorimeter qualified under real conditions during an irradiation campaign in the MARIA reactor in 2015, including previously unpublished details. Then, studies of different CALORRE calorimetric cells characterized by experiments under laboratory conditions are described. Several configurations were studied to determine the influence of cell height, horizontal fin geometry, and structural material composition on calorimeter response. These calculations provide for a calibration protocol by generating a heat source inside each cell, with evaluation of linearity, sensitivity, range, reproducibility, response time, and absolute temperatures. Finally, within the framework of a new research program called Compact-CALORimeter Irradiations inside the MIT research reactor (CALOR-I) and financed by AMU Foundation (A*Midex), a design optimization of the calorimeter assembly was carried out in order to remove contact thermal resistances and provide a new very compact CALORRE calorimeter suited for the in-core water loop of the Massachusetts Institute of Technology (MIT) reactor (2 $\text{W}\cdot \text{g}^{-1}$ peak nuclear heating rate). The response of this new very compact calorimeter is estimated using 3-D numerical thermal simulations under real conditions. [ABSTRACT FROM AUTHOR]

Recent advancements in low-energy rare-event searches rely on the use of cryogenic calorimeters in order to reach extremely low energy thresholds. When attempting to accurately characterize their responses within the region of interest (ROI) these detectors face severe challenges due to the fact that traditional radioactive calibration sources produce signals above the ROI and cannot be used in low background environments. LANTERN, an optical calibration system, can instead be used to accurately study the ROI of cryogenic detectors. It utilizes LED pulses to generate photon signals to perform detector calibration. LANTERN's current LED matrix allows for a fast characterization of up to 64 calorimeters independently, spanning energies from a few eV to hundreds of keV. Its minimal electronics and optics make it a cost-effective and customizable solution and it will be employed by the BULLKID, NUCLEUS and CRAB experiments. [ABSTRACT FROM AUTHOR]

A method for enthalpy calibration of differential scanning calorimeters is described which makes it possible to eliminate the existing limits on the temperature range within which this metrological procedure can be carried out. The proposed method does not require use of standard samples of heats of fusion, so it is not limited by the thermal properties of certified materials. This method solves the problem of increasing the accuracy of measurements of specific enthalpy and heats of phase transitions of various substances for all types of differential scanning calorimeters. The effectiveness of the proposed method for solving the accuracy problems is confirmed and illustrated by the authors by comparing the results of measurements of heats of fusion of a number of metals. Results of measurements obtained on differential scanning calorimeters calibrated by the proposed method and on the same instruments, but calibrated in accordance with the generally accepted standard method of the International Union of Pure and Applied Chemistry, are compared. During the experiment, the advantages of the enthalpy calibration method developed here are identified in terms of saving the time and the costs necessary for calibration. The results can be used in work with differential scanning calorimeters, in the development of new materials, the monitoring of technological processes, production, input, and output control, as well as in the development of methods for studying various materials using differential scanning calorimeters. [ABSTRACT FROM AUTHOR]

Pulses of narrow line-width optical photons can be used to calibrate and test sub-2 eV full-width at half-maximum (FWHM) energy resolution transition-edge sensor (TES) microcalorimeters at low energies (< 1  keV), where it is very challenging to obtain X-ray calibration lines comparable to (or narrower than) the detector resolution. This scheme depends on the ability to resolve the number of 3 eV photons in each pulse, which we have recently demonstrated up to photon numbers of about 300. At LTD-18 we showed preliminary results obtained with this technique on a 0.25 eV baseline resolution TES microcalorimeter designed for the ultra-high-resolution sub-array of the Lynx mission. The line-shape was well described by a simple Gaussian. However, the difficulty of delivering photons to the small 46 μm square absorbers resulted in a large thermal crosstalk signal, whose random nature is expected to rapidly degrade the observed energy resolution towards higher photon numbers/energies. We have since improved the coupling between the optical fiber and the TES absorber and report here our current results. [ABSTRACT FROM AUTHOR]

Wide-band-gap technologies enable ultra-high efficiencies in the high-frequency power conversion. However, inadequate accuracies in electrical measurements could lead to spurious efficiency measurements, even above 100%. Furthermore, bandwidth limitations, particularly of current probing, delay mismatches between current and voltage probes, loading effects, and electromagnetic interferences, make electrical techniques inappropriate for measuring extremely-low losses in switches with high dv/dt and di/dt values and magnetic components under high-frequency excitations. Calorimetric methods overcome this issue by a direct loss measurement through the generated heat. Nevertheless, limited ranges and accuracies of the existing systems hinder their application in sensitive measurements. Moreover, time-consuming calibrations with extensive data processing impede rapid design assessments. In this work, we propose a closed-type double-chamber calorimeter based on a real-time calibration between two identical chambers to eliminate extra compensation for ambient variations or changes within the system itself. By streaming the same coolant in both chambers, our system removes the need for flow measurements, enabling extremely low flow rates, which improves sensitivity and reduces complexity and system cost. The system provides an adjustable cooling and can measure losses down to 500 mW, enabling the evaluation of high-performance power converters and their components with no dependence on the geometry of the evaluated devices or systems. [ABSTRACT FROM AUTHOR]

The Jules Horowitz Reactor, a new material testing reactor, is currently under construction on the CEA Cadarache site (in the South of France). A nuclear heating rate unequaled in Europe will be provided: 20 W.g−1 for a nominal thermal power of 100 MW. There is no differential calorimeter in the state of the art that measures such a nuclear heating rate. This article presents a new differential calorimeter configuration dedicated to this very high nuclear heating rate. On the one hand, the chosen configuration is validated and calibrated experimentally under laboratory conditions by using a new heating system, allowing the application of a wide range of electrical power never tested in the literature and ten times higher compared to that commonly used. Then the calorimetric cell response is estimated under real conditions with an analytical model. Finally, 3-D thermal numerical simulations of the whole calorimeter are performed under real conditions. Some parameters, such as the size of the cell, the intercell space, and the nature of the sample, are tuned to propose a very compact differential calorimeter. [ABSTRACT FROM AUTHOR]

The Jules Horowitz Reactor, a new material testing reactor, is currently under construction on the CEA Cadarache site (in the South of France). A nuclear heating rate unequaled in Europe will be provided: 20 W.g−1 for a nominal thermal power of 100 MW. There is no differential calorimeter in the state of the art that measures such a nuclear heating rate. This article presents a new differential calorimeter configuration dedicated to this very high nuclear heating rate. On the one hand, the chosen configuration is validated and calibrated experimentally under laboratory conditions by using a new heating system, allowing the application of a wide range of electrical power never tested in the literature and ten times higher compared to that commonly used. Then the calorimetric cell response is estimated under real conditions with an analytical model. Finally, 3-D thermal numerical simulations of the whole calorimeter are performed under real conditions. Some parameters, such as the size of the cell, the intercell space, and the nature of the sample, are tuned to propose a very compact differential calorimeter. [ABSTRACT FROM AUTHOR]

Measurements of quantities by differential scanning calorimetry (DSC) are influenced by intrinsic factors given by the construction limits of particular DSC devices. The position of temperature sensors outside the samples causes the produced experimental outputs to suffer from signal delay or partial signal consumption. Differences in sample mass and heating rate belong to other typical sources of errors that cannot be fully eliminated even by the experimental calibration. In this article, a computational method involving detailed modeling of thermal phenomena in the calorimeter-sample system is used for the correction of inaccuracies in DSC measurements. The applied model is able to extract pure data related to the sample itself, which is free of distortion. In a practical application of the method, lime hydrate samples of various mass are analyzed at first experimentally, while several different heating rates are used, and the influence of varying parameters on the obtained outputs is recorded. The experimental data are then reconstructed using computational modeling of thermal phenomena in the calorimeter-sample system. The corrected specific heat power values are found to be up to 9% higher and can be attributed to the heat capacity of inner parts of the device that consumes a part of the heat. The highest agreement between experimental and computational outputs is achieved when a sample filling one half of the crucible’s volume is heated at 7 K. min−1. Such a parameter choice shows a low-temperature shift (<5~C), and the specific heat power difference is only 0.09 mW.mg−1 (3.4%). [ABSTRACT FROM AUTHOR]

The Large Hadron Collider beauty (LHCb) experiment is one of the four main particle detectors located at the Large Hadron Collider. After the high-luminosity upgrade of the accelerator, the expected radiation dose faced by the LHCb electromagnetic calorimeter will reach peak values of 1 MGy in the centermost part, an amount not tolerable by the currently employed Shashlik technology, which demands a novel radiation hard design. In addition, a time resolution of few tens of picoseconds and a cell lateral size of about 2 cm are planned for track reconstruction purposes by the collaboration. In this article, the crystal spaghetti design was evaluated, a sampling geometry where scintillating crystal fibers are embedded in the dense absorbing material. The prototype was tested at CERN super proton synchrotron (SPS) with muons and electrons measuring an energy resolution of 3% for electrons at 20 GeV, tilting the prototype by 3° both horizontally and vertically with respect to the incident beam, and a time resolution of 79 ps. The results presented in this article show the feasibility of the design. [ABSTRACT FROM AUTHOR]

Here, we demonstrate an accurate terahertz (THz) power calibration toward tens of nanowatt levels at room temperature. A power reference standard based on a calorimeter with extremely low noise is realized by introducing vacuum insulation panels utilized for thermal insulation. The standard provides a measurement capability of 26.7 nW with the expanded uncertainty of 4.2% (k = 2) at 1 THz. The direct‐comparison calibration of a commercially available power meter is performed by considering its detectable power levels using the standard. A thermopile‐type power meter is used as the device under test, and its calibration factors are determined at 1 and 1.5 THz over a power‐level range of 0.66–1.56 µW. We evaluate the measurement uncertainties of the calibration and find a relative expanded uncertainty of 4.8–9.0% (k = 2). © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

The ATLAS Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment at the Large Hadron Collider (LHC). This sampling calorimeter uses steel plates as an absorber and scintillating tiles as an 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 data-taking, a set of calibration subsystems 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 signal evolution, from scintillation light to digitization. Calibration runs are monitored from a data quality perspective and used as a cross-check for physics runs. Data quality in physics runs is monitored extensively and continuously. Any problems are reported and immediately investigated. The efficiency of taking high-quality data 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. [ABSTRACT FROM AUTHOR]

Circular Electron and Positron Collider (CEPC) is a large experiment facility proposed by the Chinese particle physics community. One of the running options is being the Higgs factory. The calorimeter is the main part of this experiment to measure the jet energy. Semidigital hadron calorimeter (SDHCAL) is one of the options for the hadron measurement. Gas electron multiplier (GEM) detector with its high-position resolution and flexible configuration is one of the candidates for the active layer of the SDHCAL. The main purpose of this paper is to provide a feasible readout method for the GEM-based SDHCAL. A small-scale prototype is designed and implemented, including front-end board (FEB) and data interface board (DIF). The prototype electronics has been tested. The equivalent rms noise of all channels is below 0.35 fC. The dynamic range is up to 500 fC and the gain variation is less than 1%. The readout electronics is applied on a double-layer GEM detector with 1 cm $\times 1$ cm readout pad. The result indicates that the electronics works well with the detector. The detection efficiency of minimum ionization particle (MIP) is over 95% with a 5-fC threshold. [ABSTRACT FROM AUTHOR]

Highlights • 3-D computational model of a differential scanning calorimeter is constructed. • Five reference processes are used for experimental and computational calibration. • Model is validated using two different materials. • Physical origins of measurement uncertainties can be identified. • Systematic errors involved in raw experimental data can be eliminated. Abstract Experimental results provided by differential scanning calorimetry (DSC) can be affected by systematic errors, which are difficult to identify and quantify correctly by the end-users, as a DSC device is commonly used as a gray box. The signal delay due to thermal inertia and the effects of sample size or heating rate present the most common sources of uncertainties. In this paper, a 3-D computational model of a differential scanning calorimeter is constructed, calibrated and validated. Five reference standards are used for both experimental and computational calibration, resulting in a very good agreement (R 2 > 0.999794) of the computational model with experimental outputs. Model is validated using two different materials and processes. The analysis of melting of aluminum, as one of the standards not used at the calibration, shows a maximum difference of 0.279 mW·mg−1 at the peak top, which is well within the accuracy limits. The application of the model for the determination of effective specific heat capacity of quartz, as a representative of commonly studied materials which are though not standardized for DSC, reveal a good agreement with both the measured data and the results of independent experiments reported by several other investigators. The main advantage of the model consists in the detailed analysis and separation or quantification of particular heat evolving/consuming mechanisms in both the DSC device and the studied materials. Therefore, contrary to the empirical calibration, it can identify exactly the physical sources of measurement uncertainties. The raw experimental data provided by the DSC device can then be corrected in a straightforward way and the systematic errors can be eliminated. [ABSTRACT FROM AUTHOR]