Search

COSINUS is a new cryogenic observatory for rare event searches located in the Laboratori Nazionali del Gran Sasso in Italy. COSINUS's first goal is to clarify whether the signal detected by the DAMA/LIBRA experiment originates from dark matter particle interactions or has a different nature. To this aim, sodium iodide (NaI) cryogenic scintillating calorimeters read out by transition edge sensors (TESs) are developed. To preserve the NaI crystal from the TES fabrication process, COSINUS implemented a novel design, the remoTES, where the TES is deposited on a separate wafer and coupled to the absorber through a Au-bonding wire and a Au-phonon collector. This design has reached baseline resolutions below 100 eV for Si, 200 eV for TeO 2 and 400 eV for NaI absorbers. These results show that the remoTES not only brings COSINUS close to its performance goal of 1 keV energy threshold, but also offers the possibility to employ delicate crystals previously excluded for cryogenic applications as absorbers and to avoid the exposure of the absorbers to the TES fabrication process. It therefore extends the choice of target materials of the rare event searches using TES. In this work, we will provide a detailed description of the remoTES design and present the results of the latest prototypes. [ABSTRACT FROM AUTHOR]

Studies of astromaterials provide valuable insights into the formation and evolution of the solar system. To analyze such astromaterials on a sub-micrometer scale, one of the most useful tools is energy-dispersive X-ray spectroscopy (EDS) in conjunction with scanning transmission electron microscope (STEM). The conventional semiconductor-based EDS system is sometimes insufficient to resolve emission lines at closely adjacent energies. A transition edge sensor (TES) X-ray microcalorimeter is a promising solution to overcome this problem. We developed a 64-pixel TES X-ray microcalorimeter array which had an energy resolution of approximately 7 eV (FWHM) at an energy band from B Kα to Cu Kα. However, the counting rate was only approximately 1000 count/s/array. The distance between the detector and the sample is 30 cm, limited by the stage of the refrigerator. Therefore, an X-ray polycapillary is used to focus the X-ray, which focus size is 5 mm in diameter, resulting in a detection efficiency of only 5%. To increase the effective area, we developed a large size absorber with a large-scale array. A three-dimensional structure was created to fill the dead space between TES pixels. Additionally, an array of 224 elements was made to increase the detection efficiency by a factor of 10. In this paper, we provide more details of design, fabrication process of the overhang absorber, and device performance. [ABSTRACT FROM AUTHOR]

This study analyzed the correlation between heat release rate and variations in the blower capacity ( Q fan ), hood skirt length ( L skirt ), and diameter ( D Hood ) of a calorimeter in large-scale fire experiments. The fire dynamics simulator (FDS) program was used to examine the time-averaged temperature ( T duct,avg ), flow rate ( m ˙ duct,avg ), and oxygen concentration changes ( Δ O 2 , avg ) inside the duct for n-heptane heat release rate input values ( Q ˙ input ) of 8000 kW, where Q fan = 1800 to 4000 m3 min−1, L skirt = 1 to 5 m, and D Hood = 4 to 11 m. The results showed that when L skirt = 2 m and D Hood = 9 m, as Q fan decreased, Δ O 2 , avg increased, whereas m ˙ duct,avg decreased. When Q fan = 1800 m3 min−1, the predicted heat release rate ( Q ˙ o,c ) derived from the oxygen consumption index was approximately 25% lower than Q ˙ input owing to overflow. When Q fan = 2600 m3 min−1 and D Hood = 9 m, the ambient air inflow increased as L skirt decreased. This reduced Δ O 2 , avg and T duct,avg , increasing m ˙ duct,avg . When L skirt = 1 m, Q ˙ o,c was over 20% lower than Q ˙ input . However, when Q fan = 2600 m3 min−1, L skirt = 2 m, and D Hood ≥ 4 m, D Hood did not significantly influence the design variables. Notably, T duct,avg emerged as a key variable determined by the total mass flow rate entering the calorimeter, which varied with Q fan and L skirt . Prediction equations for m ˙ duct,avg and Δ O 2 , avg in terms of T duct,avg were derived. A design range for the calorimeter heat release rate was proposed by analyzing L skirt . The findings of this study are significant for determining the range of Q fan , L skirt , and T duct,avg when designing calorimeters in the 5000–10,000 kW scale. [ABSTRACT FROM AUTHOR]

Cryogenic microcalorimeters are key tools for high-resolution X-ray spectroscopy due to their excellent energy resolution and quantum efficiency close to 100%. Multiple types of microcalorimeters exist, some of which have already proven outstanding performance. Nevertheless, they cannot yet compete with cutting-edge grating or crystal spectrometers. For this reason, novel microcalorimeter concepts are continuously developed. One such concept is based on the strong temperature dependence of the magnetic penetration depth of a superconductor operated close to its transition temperature. This so-called λ -SQUID provides an in-situ tunable gain and promises to reach sub-eV energy resolution. Here, we present some design considerations with respect to the optimization of such a detector that are derived by analytic means. We particularly show that for this detector concept the heat capacity of the sensor should match the heat capacity of the absorber. [ABSTRACT FROM AUTHOR]

We have modified the fabrication processes of metallic magnetic calorimeters (MMCs) to improve production yield. Key modifications include (i) the stress mitigation of the sputtered Nb film by optimizing the Argon deposition gas pressure, (ii) an optimized SiO x insulator layer fabrication by switching from a lift-off to a wet-etching method and controlling the optimizing the temperature, (iii) the joint electroplating of thick gold structures for persistent current switch leads and a thermalization layer, and (iv) a reduced sputter-deposition time of the Ag:Er sensor material by introducing a new wafer holder. These modifications contribute to increased production yield, reduced fabrication time, and enhanced overall performance. Tests on MMCs fabricated with these modifications demonstrated uniformly improved critical current of the Nb meander coils, enhanced SiO x insulation properties, strengthened persistent current switch systems, and reduced probability of Ag:Er oxidation. These modified MMC detectors also functioned well in tests for alpha spectrometry measurements, demonstrating good performance. [ABSTRACT FROM AUTHOR]

Superconducting transition-edge sensors (TESs) used in X-ray and γ -ray microcalorimeters suffer degraded performance if cooled in a magnetic field B sufficient to trap flux in the sensors. We report measurements of γ -ray TESs before and after implementing measures to reduce stray B fields from sources inside and outside the cryostat. These measurements showed a correlation between anomalous features in TES current–voltage (IV) curves and degraded energy resolution. After reducing internal sources of stray B field and improving shielding against external sources, both IV curves and energy resolution improved. Finally, we placed magnetized screws with remnant fields ∼ 10 μ T near similar γ -ray TESs in a different type of detector package and observed the same effects. [ABSTRACT FROM AUTHOR]

We present advancements in a finite element method for computing the physical properties of magnetic microcalorimeters (MMCs). Utilizing the COMSOL package, we conducted 3D simulations of a meander-shaped Nb coil with a realistic geometry. The resulting magnetic field distribution showed good agreement with a previous 2D simulation and revealed non-negligible differences at the side edge of the sensor material. Employing the simulation results, we calculated the MMC properties and compared them with previous measurements. Our calculated values closely align with the measured values for the sensor magnetization, the pulse heights from alpha detection, and the coil inductance. [ABSTRACT FROM AUTHOR]

We study the thermal properties of a bulk Ni 55 Fe 19 Ga 26 Heusler alloy in a conduction calorimeter. At slow heating and cooling rates ( ∼ 1 K h - 1 ), we compare as-cast and annealed samples. We report a smaller thermal hysteresis after the thermal treatment due to the stabilization of the 14 M modulated structure in the martensite phase. In ultraslow experiments ( 40 mK h - 1 ), we detect and analyze the calorimetric avalanches associated with the direct and reverse martensitic transformation from cubic to 14 M phase. This reveals a distribution of events characterized by a power law with exponential cutoff p (u) ∝ u - ε exp (- u / ξ) where ε ∼ 2 and damping energies ξ = 370 μ J (direct) and ξ = 27 μ J (reverse) that characterize the asymmetry of the transformation. [ABSTRACT FROM AUTHOR]

The growing interest of human skin thermal properties is motivating the development of new instruments, either by contact or by remote sensing. In this work, we show the ability of a skin calorimeter to monitor the temporal evolution of the heat capacity and the equivalent thermal resistance of the skin, in two small skin lesions. The first one consists of a forehead wound of 10 × 2 mm2. The other injury consists of a second degree burn on the volar wrist area, of 10 × 20 mm2. We studied the temporal evolution of the thermal properties of both injuries. The variation of heat capacity was significant. For first injury, heat capacity decreased by 21% and full recovery was achieved after ten days. For the second case, the heat capacity decrease was 55% and recovery was achieved after 3 weeks. These skin recoveries are monitored by the measured heat capacity value. The returning of the heat capacity to its normal value coincides with the recovery from the injury. [ABSTRACT FROM AUTHOR]

The precise reconstruction of properties of photons and electrons in modern high energy physics detectors, such as the CMS or ATLAS experiments, plays a crucial role in numerous physics results. Conventional geometrical algorithms are used to reconstruct the energy and position of these particles from the showers they induce in the electromagnetic calorimeter. Despite their accuracy and efficiency, these methods still suffer from several limitations, such as low-energy background and limited capacity to reconstruct close-by particles. This paper introduces an innovative machine-learning technique to measure the energy and position of photons and electrons based on convolutional and graph neural networks, taking the geometry of the CMS electromagnetic calorimeter as an example. The developed network demonstrates a significant improvement in resolution both for photon energy and position predictions compared to the algorithm used in CMS. Notably, one of the main advantages of this new approach is its ability to better distinguish between multiple close-by electromagnetic showers. [ABSTRACT FROM AUTHOR]

Methylene diphenyl diisocyanate (MDI) serves as a primary component of polyurethane in various applications, including household appliances, architectural structures, automobiles, and adhesives. A recent MDI plant explosion in China highlighted the importance of studying MDI's thermal stability and parameters to prevent accidental thermal decomposition. In this study, an extensive array of analytical techniques, including differential scanning calorimetry, thermogravimetric analysis, and adiabatic accelerating calorimeter, was employed to determine the thermokinetic constants of MDI, providing a solid foundation for further in-depth investigations. The findings revealed that MDI containing water reacts at substantially lower temperatures, while pure MDI can release heat and gases in an adiabatic environment, posing a considerable explosion risk. The kinetic constant of MDI was calculated using the Flynn–Wall–Ozawa method, yielding apparent activation energy values ranging from 51.78 to 96.70 kJ mol−1 across a conversion degree range of 0.05–0.70. The Coats–Redfern model pinpointed the kinetic reaction mechanism as a two-stage chemical process based on the apparent activation energy. Molecular optimization, following the energy minimisation principle, was conducted using Gaussian 09 software, which led to the identification of the optimal pathway for generating carbodiimide and carbon dioxide. This investigation offers valuable insights for the effective management of MDI during production, transportation, and storage, contributing to improve loss prevention practices in the industry. [ABSTRACT FROM AUTHOR]

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]

Metallic magnetic calorimeters (MMC) are low-temperature particle detectors based on calorimetry. They typically operate at temperatures below 100 mK. They utilize a metallic paramagnetic temperature sensor to convert the temperature rise of an absorber, during the absorption of energetic particles, into a change in magnetic flux sensed by a superconducting quantum interference device (SQUID). Since the SQUID has a high sensitivity to magnetic signals, the MMC system is very sensitive to external magnetic field interference. The magnetic shielding effect of the MMC directly affects its detection capability. Therefore, the design of the MMC magnetic shield system is particularly important. In this study, a set of MMC magnetic shields is designed based on the principle of magnetic shielding. The design is optimized using the COMSOL magnetic field simulation module by varying relevant parameters, such as the thickness and height of the shields as well as the diameter of the radioactive source hole, which determines the magnetic shielding effect. Through the simulation, the optimized magnetic shielding device can reduce the magnetic field interference of 2–0.0264 nT. The value can be further reduced by one order of magnitude if a high-permeability material with superior performance is used. This research is instructive for the design of MMC magnetic shielding devices in subsequent experiments. [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]

The precision of existing decay data of radionuclides for activity determination is often a limitation for actual applications in science, society and industry. For this reason, the EMPIR project PrimA-LTD aims to introduce an advanced primary activity standardization technique that is based on magnetic microcalorimeters (MMCs) and that will offer very low energy threshold of few eV and a decay scheme-independent detection efficiency close to 100 % . As a proof of concept, we developed two MMC-based detector types in order to standardize an α -decaying, a β -decaying and an electron capture decaying isotope. One detector type aims to introduce a reusable detector setup, while the other aims to provide highly accurate decay spectra by high-resolution measurements with high statistics. We present the designs, fabrication status and first characterization measurements of both detectors types and outline next steps. [ABSTRACT FROM AUTHOR]

The LHC Phase II Upgrade foreseen for 2026 implies multi fold increasing of number of collisions and radiation levels compared to the present LHC conditions. The electromagnetic calorimeter (ECAL) of LHCb experiment requires modernization due to enlarged radiation doses and high occupancy: replacing shashlik-type modules for the central part by spaghetti-type (SPACAL) calorimeter. Current paper presents results of the material optimization (fiber diameter and distance between their centers (pitch), absorber material) for lead-polystyrene SPACAL module performed with GEANT4 simulation to satisfy the LHCb requirements in terms of energy resolution. [ABSTRACT FROM AUTHOR]

The upcoming LHCb calorimetry upgrade implies significant modifications to the present detector system. These changes include modifications to the Electromagnetic Calorimeter (ECAL) and possible removal of the Hadron Calorimeter. Such changes require detailed studies, including the test beam campaign. This paper presents the results of the hadron beam particle composition analysis performed at CERN SPS H8 testbeam line. The analysis is based on the data recorded with a single-cell LHCb ECAL module, threshold Cherenkov detector and tracking system based on delay-wire chamber stations. [ABSTRACT FROM AUTHOR]

We study single-image super-resolution algorithms for photons at collider experiments based on generative adversarial networks. We treat the energy depositions of simulated electromagnetic showers of photons and neutral-pion decays in a toy electromagnetic calorimeter as 2D images and we train super-resolution networks to generate images with an artificially increased resolution by a factor of four in each dimension. The generated images are able to reproduce features of the electromagnetic showers that are not obvious from the images at nominal resolution. Using the artificially-enhanced images for the reconstruction of shower-shape variables and of the position of the shower center results in significant improvements. We additionally investigate the utilization of the generated images as a pre-processing step for deep-learning photon-identification algorithms and observe improvements in the case of training samples of small size. [ABSTRACT FROM AUTHOR]

The ALICE experiment at the LHC is designed to explore the hot and dense medium produced in heavy-ion collisions, the so-called quark–gluon plasma (QGP). Antineutron production is a poorly explored domain of high energy physics, although it is interesting in the context of hadrons decaying into antineutrons, the interaction of antineutrons with hadrons, and searching for bound states of antineutrons. We present a method for measuring antineutrons by the electromagnetic calorimeter PHOS of the ALICE experiment. An antineutron can be identified by the cluster shape and the energy deposition in the calorimeter, and its momentum can be reconstructed using the time-of-flight information. The proposed method was verified via the reconstruction of through decays and with an antineutron identified in the PHOS. [ABSTRACT FROM AUTHOR]

The LHCb Upgrade phase II conditions require a significant change of the detector systems including the electromagnetic calorimeter (ECAL), which must be capable to sustain high radiation doses in the innermost region and provide good time resolution. The central part of the ECAL will be substituted by spaghetti calorimeter (SPACAL). This paper presents the results of the first cast lead–polystyrene SPACAL prototypes studies performed at the CERN SPS and DESY test beam areas. [ABSTRACT FROM AUTHOR]

Cone calorimeters are widely used to assess heat release parameters and flammability of combustible materials, but their use is limited for applications where the global equivalence ratio (GER) exceeds one, because they can only replicate burning in open conditions. The standardisation of the controlled atmosphere cone calorimeter (CACC) in the ISO/TS 5660-5:2020 offers an opportunity to investigate the potential advantages and limitations of this apparatus. This paper presents a detailed review of existing studies conducted using the CACC. The review is aimed at examining the importance of atmospheric control for bench-scale experimental methods and the research-based development of key features of the apparatus. In addition, it highlights the research yet to be carried out to optimise the use of CACC as a tool in fire science. The effects of various design parameters are discussed including the method used for GER control, the chimney, the chamber, the gas inflow rate and others. Despite standardisation, it is concluded that there is limited consensus on optimal CACC control variables. A lack of consensus has led to significantly different testing conditions even where researchers use the same materials and have similar research objectives. The lack of best practice, particularly with regards to a gas sampling location and the method of GER control, motivates the need for further research so as to improve the value of data collected, reduce uncertainty and optimise CACC reproducibility. [ABSTRACT FROM AUTHOR]

Using the small-x improved transverse momentum dependent factorization (ITMD), which, for a general two-to-two massless scattering can be proved within the color glass condensate (CGC) theory for transverse momenta of particles greater than the saturation scale, we provide predictions for isolated forward photon and jet production in proton-proton and proton-nucleus collisions within the planned ALICE FoCal detector acceptance. We study azimuthal correlations, p T spectra, as well as normalized ratios of proton-proton cross sections for different energies. The only TMD distribution needed for that process is the "dipole" TMD gluon distribution, which in our computations is based on HERA data and undergoes momentum space BK evolution equation with DGLAP corrections and Sudakov resummation. We conclude, that the process provides an excellent probe of the dipole TMD gluon distribution in saturation regime. [ABSTRACT FROM AUTHOR]

This work evaluates the effects of the acidity of montmorillonites on the thermal degradation process and in the cone calorimeter parameters of an intumescent composite constituted by polypropylene, ammonium polyphosphate (APP) and pentaerythritol (PER). The cone calorimeter tests showed that the absence of moderate-strength acidic sites is related to the increase in the peak of heat release rate. The composites were burnt at different key-temperatures and the residues were submitted to Fourier transform infrared spectroscopy, Solid State Nuclear Magnetic Resonance Spectroscopy and to X-ray diffraction. The results showed that the addition of the clay minerals is important to preserve the char at higher temperatures (over 430 °C) and that an excess of Brønsted sites over the Lewis ones with moderate-strength could lead to the increase of the esterification reactions between PER and APP. Besides, the addition of the clay minerals did not affect the mechanical properties of the composites. [ABSTRACT FROM AUTHOR]

Recently, with the extensive use of lithium-ion batteries (LIBs) in particular important areas such as energy storage devices, electric vehicles (EVs), and aerospace, the accompanying fire safety issues are also emerging and need to be taken into account seriously. Here, a series of experiments for LIB packs with five kinds of pack sizes (1 × 1, 1 × 2, 2 × 2, 2 × 3, 3 × 3) and three types of different state of charge (SOC) (100%, 50%, and 0%) were carried out using a cone calorimeter. Relevant fire parameters such as heat release rate (HRR), mass loss, and concentrations of CO, CO2, and O2 were investigated. Remarkably similar combustion phenomena with intermittent jets were observed for LIB packs with 50% SOC and 100% SOC. The total mass loss (TML) and the peak value of HRR (pHRR) showed a similar positive correlation relationship of a power function with the surface area of the exposed heat source. For battery packs with 100% SOC, the pHRR of 3 × 3 cell module even increased by about 8 times to 12 kW. The content of toxic gas CO was evaluated by determining fractional effective dose (FED). It could be concluded that when the pack size was smaller than 2 × 3, the FED was below 1 for battery packs with 50% SOC and 100% SOC. This study can help predict the development patterns and fire risk of more large-scale battery fires and further diminish the thermal runaway (TR) hazard during an accident. [ABSTRACT FROM AUTHOR]

We report on an experiment conducted at the ESR storage ring aiming at the study of the X-ray emission of Xe 54 + ions colliding with Xe atoms at a beam energy of 50 MeV/u. The radiation resulting from the ion–atom interaction was observed using a high-resolution spectrometer based on metallic–magnetic calorimeter technology. In order to benchmark the capabilities of these detectors for high-precision atomic physics experiments, we identified several transitions from H-like and He-like xenon and determined their energies. Furthermore, the 1s-Lamb shift in Xe 53 + was estimated using the measured line energies. The results are compared with previous experimental studies and theoretical predictions. [ABSTRACT FROM AUTHOR]

During a failure event, electrochemical cells can exhibit such characteristics as extreme high temperatures, deflagration, fire, venting of electrolyte and rapid uncontrolled disassembly. The cell's characteristics prior to, during, and after a destructive event are important in developing preventive and mitigating hazard steps. A novel measuring system based on isothermal calorimetry has been developed and utilized to further understand the worst-case event produced by large format electrochemical cells. This system allows for the containment of the reaction and its products while measuring the pressure and release rate of the gaseous product, as well as a complete thermal profile of the reaction. This paper provides a description of the calorimeter, calibration test results on its performance, test results, and empirical model from a selection of cells tested. The cells utilized in this developmental testing were Lithium Iron Phosphate and Lithium Cobalt Oxide cells ranging from 6 to 38 Ampere hour capacities and approximately 40 mm diameter, 170 mm height, and 0.35 kg each. This analytical system allows for a wide range of cells, chemistries, failure mechanisms and testing environments for lithium-ion cells, static or under load. Empirical models developed from this flexible and adaptive system will enable researchers to compare larger samples across material property boundaries to better predict the outcome of destructive chemical reactions. [ABSTRACT FROM AUTHOR]

The Future Circular Collider FCC-ee aims at unprecedented luminosities to be obtained with the crab-waist collision scheme. In this paper we describe the mechanical model of the interaction region layout including its assembly procedure. After a discussion on the requirements and constraints, we present the engineered design of the vacuum chamber with the cooling system, the bellows, the vertex and outer tracker detectors and their integration in a carbon-fibre lightweight support structure that will support also the luminosity calorimeter. [ABSTRACT FROM AUTHOR]

A 57 Fe nucleus in the solar core could emit a 14.4-keV monochromatic axion through the M1 transition if a hypothetical elementary particle, axion, exists to solve the strong CP problem. Transition edge sensor (TES) X-ray microcalorimeters can detect such axions very efficiently if they are again converted into photons by a 57 Fe absorber. We have designed and produced a dedicated TES array with 57 Fe absorbers for the solar axion search. The iron absorber is set next to the TES, keeping a certain distance to reduce the iron-magnetization effect on the spectroscopic performance. A gold thermal transfer strap connects them. A sample pixel irradiated from a 55 Fe source detected 698 pulses. In contrast to thermal simulations, we consider that the pulses include either events produced in an iron absorber or gold strap at a fraction dependent on the absorption rate of each material. Furthermore, photons deposited on the iron absorber are detected through the strap as intended. The identification of all events still needs to be completed. However, we successfully operated the TES with the unique design under iron magnetization for the first time. [ABSTRACT FROM AUTHOR]

Prediction of flammability characteristics of materials is possible via molar group contribution calculations. However, in most industries raw material composition is unknown and micro combustion calorimeter (MCC) is applied for measuring heat release rate (HRR) and calculates flammability characteristics. This work predicts HRR and flammability characteristics for complex formulations based on HRR from a reduced number of the individual constituents, all with unknown chemical composition. Water-based paints (> 15 components) with and without chemical interaction during thermal decomposition were predicted via linear combinations of component HRR and validated against experimental MCC data. Prediction of HRR and flammability characteristics was successful, and the obvious breakdown for reactive mixtures was confirmed. These results can be utilized as screening tool for flammability characteristics and identity component interaction in mixtures—which considerably enhances the strength of MCC in development of new materials. [ABSTRACT FROM AUTHOR]

The time and energy resolutions were measured for four prototypes of the PHOS electromagnetic calorimeter for the ALICE experiment at the Large Hadron Collider at CERN. Each prototype was made up of nine identical detection elements assembled as a 3 × 3 array. The detection element was based on a lead tungstate (PbWO4) scintillating crystal with a length of 180 mm and a cross section of 22 × 22 mm2, which was viewed from its end face by a photodetector. Avalanche photodiodes and silicon photomultipliers with different active areas (Hamamatsu, Japan) were used as photodetectors. The measurements were made with the electron component of secondary particle beams of the PS proton synchrotron at CERN in the momentum range of 1−10 GeV/c at a temperature of 17.5°C. [ABSTRACT FROM AUTHOR]

Continuous flow calorimeters are a promising tool in process development and safety engineering, especially for flow chemistry applications to characterize the heat release and kinetic parameters of rapid chemical reactions. In this study, the digital accompaniment of an isoperibolic flow calorimeter for characterization of exothermic reactions is presented. To support experimental planning and evaluation, computational fluid dynamic simulations are carried out for single-phase flow in the microreactor. The residence time distribution is obtained and used for estimation of conversion and temperature profiles along the microreactor channel. This leads to an integration of CFD simulations into the calorimeter's software-guided workflow reducing the experimental effort regarding the determination of thermokinetic data. The approach is tested for a highly exothermic test reaction, which provides further hints for future investigations. Article highlights: • Estimation of conversion and temperature profiles within a microscale calorimeter • Combination of CFD simulations and reactor performance estimation • Approach was tested for highly oxidation of sodium thiosulfate • Estimated conversion and temperature profiles are in good agreement with experimental data Graphical abstract [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]

We have developed an algorithm dedicated to timing reconstruction in highly granular calorimeters (HGC). The performance of this algorithm is evaluated on an electromagnetic calorimeter (ECAL) with geometries comparable to the electromagnetic compartment (CE-E) of the CMS endcap calorimeter upgrade at HL-LHC and conceptual Particle Flow oriented ECAL's for future Higgs factories. The time response of individual channel is parameterized according to the CMS experimental result (Akchurin et al. in Nucl Instrum Methods Phys Res Sect A Accel Spectrom Detect Assoc Equip 859:31, 2017). The particle Time-of-Flight (ToF) can be measured with a resolution of 5–20 ps for electromagnetic (EM) showers and 80–160 ps for hadronic showers above 1 GeV. The presented algorithm provides comparable reconstruction with the E hit 2 weighting strategy and can significantly improve the time resolution compared to a simple averaging of the fast component of the time spectrum. The effects of three detector configurations are also quantified in this study. ToF resolution depends linearly on the timing resolution of a single silicon sensor and improves statistically with increasing incident particle energy. The timing layers at depth of 6–9 radiation lengths provide higher timing performance for EM showers. A clustering algorithm that vetoes isolated hits improves ToF resolution. [ABSTRACT FROM AUTHOR]

The LUCE (LUtetium sCintillation Experiment) project will search for the 176\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$^{176}$$\end{document}Lu electron capture based on a milli-Kelvin calorimetric approach. This decay is of special interest in the fields of nuclear structure, rare event searches, and measurements of nuclear matrix elements of long-lived isotopes. The experiment is primarily searching for a mono-energetic peak from the 7-→2+\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$7^- \rightarrow 2^+$$\end{document} forbidden transition. The current status and design of a novel cryogenic module for the measurements of the electron capture in 176\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$^{176}$$\end{document}Lu are reported on. Details of future measurement plans are presented. [ABSTRACT FROM AUTHOR]

ALICE is a high-energy physics experiment at the CERN Large Hadron Collider (LHC) in Geneva, to study the properties of quark-gluon plasma, formed in heavy-ion collisions. In the upgrade program, a new electromagnetic forward calorimeter (FOCAL) based on silicon and tungsten (Si + W) sampling configuration, has been proposed to address new physics objectives of ALICE experiment. The high luminosity environment of the LHC and the requirement of compact design for the FOCAL, put stringent requirements for the development of silicon detector and front-end electronics (FEE). The ALICE-India collaboration made the first proposal for the FOCAL in the year 2008, and initiated indigenous R &D activities for silicon detectors, FEE and instrumentation. As a result, large area (40 cm 2 ), segmented silicon pad sensors (6.3 cm × 6.3 cm with 36 pads) and two different FEE application-specific integrated circuits (ASICs), ANUSANSKAR and ANUINDRA respectively, were developed. Progressive FOCAL prototypes were built using these sensors and ASICs, which have undergone test beam validation in a phased manner achieving the desired calorimetric performances, in line with the GEANT-based performance simulations. Further, the results of the test beam experiments provided crucial inputs for achieving the technical specifications of the silicon detector and readout electronics for the final calorimeter. This manuscript presents, in a chronological order, India's indigenous FEE ASICs, sensor and instrumentation development and reports the subsequently improved readout methodology for the prototype FOCAL detector. [ABSTRACT FROM AUTHOR]

The receiver calorimeter (RC) is one of the main elements of the beam path of an atomic beam injector with ballistic focusing. A water-cooled RC developed for an injector of a focused beam of fast deuterium atoms with a beam power of more than 1 MW and pulse duration of 2 s [1] installed at the variable configuration tokamak (TCV) in Lausanne (Switzerland) is considered. The design of the RC includes receiving plates with liquid flow swirlers installed in them to enhance heat transfer and pipe-in-pipe collectors of water inlet and water outlet that provide the movement into a vacuum. These technical solutions made it possible to achieve good energy efficiency of the device with very small overall dimensions and mass flow of the coolant. The design of the main elements of the calorimeter is described. The results of simulation of the coolant flow and heat transfer and some experimental data are presented. [ABSTRACT FROM AUTHOR]

AMoRE is an international project to search for the neutrinoless double beta decay of 100 Mo using a detection technology consisting of magnetic microcalorimeters (MMCs) and molybdenum-based scintillating crystals. Data collection has begun for the current AMORE-I phase of the project, an upgrade from the previous pilot phase. AMoRE-I employs thirteen 48 depl. Ca 100 MoO 4 crystals and five Li 2 100 MoO 4 crystals for a total crystal mass of 6.2 kg. Each detector module contains a scintillating crystal with two MMC channels for heat and light detection. We report the present status of the experiment and the performance of the detector modules. [ABSTRACT FROM AUTHOR]

Sm–Nd chronometers use 146 Sm and 147 Sm to determine the ages of major events in the early Solar System. Their half-lives are the most important nuclear parameters determining the accuracy of chronometry. However, the 146 Sm half-life is not well-established: the published values differ by ∼ 30%, which results in significant uncertainties in the Solar System timeline. We are re-measuring the half-lives of 146 Sm and 147 Sm using decay energy spectroscopy and metallic magnetic calorimeters to improve the accuracy of the Sm–Nd chronometers. We report recent experimental results from our first measurement of a 147 Sm source, as well as status and plans for experiments on 146 Sm. [ABSTRACT FROM AUTHOR]

Fractional electron capture probability ratios of 125I were measured using metallic magnetic calorimeters (MMCs). Due to the 4π geometry of the source embedded in the absorber, detection efficiency of nearly 99% was observed for K, L, M, and N capture events. The fractional capture probabilities were calculated from peak area ratios. [ABSTRACT FROM AUTHOR]

Using dilute silver erbium alloys as a paramagnetic temperature sensor in metallic magnetic calorimeters (MMCs) has the advantage of the host material not having a nuclear quadrupole moment, in contrast to the alternative of using gold erbium alloys. We present numerical calculations of the specific heat and magnetization of Ag:Er, which are necessary for designing and optimizing MMCs using this type of alloy as sensor material. The parameter ranges we consider are temperatures between 1 mK and 1 K , external magnetic fields of up to 20 mT , and erbium concentrations of up to 2000 ppm . The system is dominated by an interplay of crystal field effects, Zeeman splitting, and the RKKY interaction between erbium ions, with certain specific constellations of erbium ions having noticeable effects on the specific heat. Increasing the external magnetic field or assuming a decreased strength of the RKKY interaction leads to a higher magnetization and a narrowing of the main Schottky peak, while changes in the erbium concentration can be well described by parameter scaling. [ABSTRACT FROM AUTHOR]

CUORE Upgrade with Particle IDentification (CUPID) is a foreseen ton-scale array of Li2MoO4 (LMO) cryogenic calorimeters with double readout of heat and light signals. Its scientific goal is to fully explore the inverted hierarchy of neutrino masses in the search for neutrinoless double beta decay of 100Mo. Pile-up of standard double beta decay of the candidate isotope is a relevant background. We generate pile-up heat events via injection of Joule heater pulses with a programmable waveform generator in a small array of LMO crystals operated underground in the Laboratori Nazionali del Gran Sasso, Italy. This allows to label pile-up pulses and control both time difference and underlying amplitudes of individual heat pulses in the data. We present the performance of supervised learning classifiers on data and the attained pile-up rejection efficiency. [ABSTRACT FROM AUTHOR]

The ECHo experiment aims at determining the effective electron neutrino mass by analyzing the endpoint of the 163Ho electron capture spectrum. High energy resolution detectors with a well-tailored detector response are the essential ingredient for the success of the ECHo experiment. Metallic magnetic calorimeter arrays enclosing 163Ho have been chosen for the ECHo experiment. The first MMC array, ECHo-1k, showed excellent performances with an average energy resolution of 5.5 eV FWHM @ 5.9 keV. Based on the results obtained with the ECHo-1k array, optimization studies have paved the way towards a new detector design for the next experimental phase, ECHo-100k. The ECHo-100k chip features an optimized single pixel design to improve the detector performance as well as an upgraded on-chip thermalization layout. The newly fabricated ECHo-100k detectors have been fully characterized at room temperature, at 4 K and at millikelvin temperature. The obtained results show that the ECHo-100k array achieved the expected performance with an average energy resolution of 3.5 eV FWHM @ 5.9 keV, fulfilling the requirements for the ECHo-100k experimental phase. [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]

We are developing transition-edge sensor microcalorimeters for the X-ray integral field unit (X-IFU) on-board ESA's Athena space telescope. These detectors will be read out using time-domain multiplexing. Due to the limitations on bandwidth and dynamic range of the readout, the optimally filtered pulse heights of the measured X-ray signals suffer from a nonlinear variation with the exact photon arrival time relative to the sampling points. The shape and magnitude of this variation depend on the photon energy. We describe a method to characterize this energy-dependent variation with few parameters, which can then be interpolated to correct event energies across the whole spectrum. We implement our method on measurements from 200 pixels in a prototype X-IFU kilo-pixel array readout using 8-column × 32-row TDM. We show that the interpolation errors between calibration points, over the energy range 4–12 keV, can be made sufficiently small that they do not adversely impact the measured energy resolution across the full spectral range. [ABSTRACT FROM AUTHOR]

Optimal filtering is the crucial technique for the data analysis of transition-edge-sensor (TES) calorimeters to achieve their state-of-the-art energy resolutions. Filtering out the 'bad' data from the dataset is important because it otherwise leads to the degradation of energy resolutions, while it is not a trivial task. We propose a neural network-based technique for the automatic goodness tagging of TES pulses, which is fast and automatic and does not require bad data for training. [ABSTRACT FROM AUTHOR]

Transition-edge sensor (TES) calorimeters will contribute to reducing the uncertainty in the dosimetry of carbon ion beams. A TES coupled to a large graphite absorber was designed to measure the energy deposited on materials which are similar to body tissues. We have demonstrated that a TES with a graphite absorber can be applied to the detection of particles. [ABSTRACT FROM AUTHOR]

This study attempted to develop detection methods for solar axions using transition-edge-sensor (TES) microcalorimeters. Since the axion absorber comprised of iron-57 (57Fe) is electroplated upon the membrane instead of directly onto the TES itself (with the absorber hence thermally connected to the TES via a gold thermal strap), some of the heat deposited into the absorber consequently escapes into the heat bath through the membrane before being detected by the TES. If the heat-loss depends upon the axion interaction position within the absorber, position dependence may degrade the energy resolution. Therefore, this study endeavored to evaluate the dependence of heat-loss and pulse shape on axion incident position with the COMSOL Multiphysics software package (using a finite element method). In addition, heat-loss and pulse shape were likewise evaluated when the energy was deposited directly within the gold thermal strap. [ABSTRACT FROM AUTHOR]

Superconducting transition-edge sensor (TES) microcalorimeters have great utility in X-ray applications owing to their high energy resolution, good collecting efficiency and the feasibility of being multiplexed into large arrays. In this work, we develop hard X-ray TESs to measure the absolute energies of muonic-argon (μ-Ar) transition lines around 44 keV and 20 keV. TESs with sidecar absorbers of different heat capacities were fabricated and characterized for their energy resolution and calibration uncertainty. We achieved ~ 1 eV absolute energy measurement accuracy at 44 keV, and < 12 eV energy resolution at 17.5 keV. [ABSTRACT FROM AUTHOR]

Due to the periodic characteristics of SQUIDs, a suitable linearization technique is required for SQUID-based readout. Flux-ramp modulation is a common linearization technique and is typically applied for the readout of a microwave SQUID multiplexer as well as since recently also for dc-SQUIDs. Flux-ramp modulation requires another stage in the signal processing chain to demodulate the SQUID output signal before further processing. For cryogenic microcalorimeters, the signal contains events that are given by a fast exponentially rising and slowly exponentially decaying pulses shape. The events shall be detected by a trigger engine and recorded by a storage logic. Since the data rate can be decreased significantly by demodulation and event detection, it is desirable to do both steps on the deployed fast FPGA logic during measurement before passing the data to a general-purpose processor. In this contribution, we show the implementation of efficient multi-channel flux-ramp demodulation computed at run-time on a SoC-FPGA. Furthermore, a concept and implementation for an online trigger and buffer mechanism with its theoretical trigger loss rates depending on buffer size is presented. Both FPGA modules can be operated with up to 500 MHz clock frequency and can efficiently process 32 channels. Correct functionality and data reduction capability of the modules are demonstrated in measurements utilizing magnetic microcalorimeter irradiated with an Iron-55 source for event generation and read out by a microwave SQUID multiplexer. [ABSTRACT FROM AUTHOR]

The electron capture in 163 Holmium (ECHo) experiment seeks to achieve sub-eV sensitivity of the electron neutrino mass through calorimetric decay spectroscopy of 163 Ho in large arrays of cryogenic magnetic microcalorimeters (MMCs). Microwave SQUID multiplexing serves to efficiently increase the number of readout channels, thus calorimeters per array and ultimately per cryostat. A corresponding frequency multiplexing room temperature software-defined radio (SDR) system is in development to enable the readout of this increased number of MMCs per cable. The SDR consists of a custom FPGA platform that provides signal generation and analysis capabilities, as well as tailored signal conversion and analog conditioning front end electronics that enable the room-temperature-to-cryogenic interface. Ultimately, the system will read out 400 multiplexer channels with double pixel detectors through a bandwidth of 4 GHz (IEEE C band). As high-resolution data converters are limited in sample rate, the C-band is split into five sub-bands using a two-stage mixing method. In this contribution, a prototype of the heterodyne RF design is presented. It comprises one of the five 800 MHz sub-bands for a target frequency range between 4 and 8 GHz. Furthermore, the second version of the A/D converter stage is presented, capable of generating and digitizing up to five complex basebands using 1 GSs - 1 converters, the reference clocks and a flux-ramp signal. We will show first results of their single and combined characterization in the lab. The current state of the prototype hardware enables preliminary measurements, only limited in bandwidth and with slightly higher noise. Potential improvements could be derived and will be implemented in the full bandwidth, 5-sub-band RF PCB design. [ABSTRACT FROM AUTHOR]