High-resolution Calorimeter Research Articles

Main results of the DAMPE space detector after 4 years in orbit

The DArk Matter Particle Explorer (DAMPE) is a high-performance space particle detector launched in orbit in 2015 by a collaboration of Chinese, Italian and Swiss scientific institutions, coordinated by the Chinese Academy of Sciences. It consists of a high-resolution segmented BGO electromagnetic calorimeter with a depth of 32 radiation lengths, a silicon-tungsten tracker-converter with an angular resolution below [Formula: see text], an anti-coincidence shield and ion detector, and a neutron detector. The detector characteristics and performance, and the latest observations of cosmic electrons up to 5 TeV, protons and nuclei up to 100 TeV and gamma-rays up to 10 TeV are presented.

New perspectives on segmented crystal calorimeters for future colliders

Crystal calorimeters have a long history of pushing the frontier on high-resolution electromagnetic (EM) calorimetry for photons and electrons. We explore in this paper major innovations in collider detector performance that can be achieved with crystal calorimetry when longitudinal segmentation and dual-readout capabilities are combined with a new high EM resolution approach to Particle Flow in multi-jet events, such as e+e+→ HZ events in all-hadronic final-states at Higgs factories. We demonstrate a new technique for pre-processing π0 momenta through combinatoric di-photon pairing in advance of applying jet algorithms. This procedure significantly reduces π0 photon splitting across jets in multi-jet events. The correct photon-to-jet assignment efficiency improves by a factor of about 3 when the EM resolution is improved from 15 to 3%/√E. In addition, the technique of bremsstrahlung photon recovery significantly improves electron momentum measurements. A high EM resolution calorimeter increases the Z boson recoil mass resolution in Higgstrahlung events for decays into electron pairs to 80% of that for muon pairs. We present the design and optimization of a highly segmented crystal detector concept that achieves the required energy resolution of 3%/√E, and a time resolution better than 30 ps providing exceptional particle identification capabilities. We demonstrate that, contrary to previous detector designs that suffered from large neutral hadron resolution degradation from one interaction length of crystals in front of a sampling hadron calorimeter, the implementation of dual-readout on crystals permits to achieve a resolution better than 30%/√E⊕ 2% for neutral hadrons. Our studies find that the integration of crystal calorimetry into future Higgs factory collider detectors can open new perspectives by yielding the highest level of combined EM and neutral hadron resolution in the PFA paradigm.

Commissioning of the CALIFA Barrel Calorimeter of the R3B Experiment at FAIR

CALIFA is the high efficiency and energy resolution calorimeter for the R3B experiment at FAIR, intended for detecting high energy charged particles and γ-rays in inverse kinematics direct reactions. It surrounds the reaction target in a segmented configuration of Barrel and Forward End-Cap pieces. The CALIFA Barrel consists of 1952 detection units made of CsI(Tl) long-shaped scintillator crystals, and it is being commissioned during the Phase0 experiments at FAIR. The first setup for the CALIFA Barrel commissioning is presented here. Results of detector performance with γ-rays are obtained, and show that the system fulfills the design requirements.

Enhanced Electrocaloric Effect in 0.73Pb(Mg1/3Nb2/3)O3-0.27PbTiO3 Single Crystals via Direct Measurement

Electrocaloric properties of [110] and [111] oriented 0.73Pb(Mg1/3Nb2/3)O3-0.27PbTiO3 single crystals were studied in the temperature range of 293–423 K. The Maxwell relations and the Landau–Ginsburg–Devonshire (LGD) phenomenological theory were employed as the indirect method to calculate the electrocaloric properties, while a high-resolution calorimeter was used to measure the adiabatic temperature change of the electrocaloric effect (ECE) directly. The results indicate that the directly measured temperature changes of ΔT > 2.5 K at room temperature were procured when the applied electric field was reversed from 1 MV/m to −1 MV/m, which are larger than those deduced pursuant to the Maxwell relation, and even larger than those calculated using the LGD theory in the temperature range of 293–~380 K.

Performance recovery of long CsI(Tl) scintillator crystals with APD-based readout

CALIFA is the high efficiency and energy resolution calorimeter for the R3B experiment at FAIR, intended for detecting high energy light charged particles and gamma rays in scattering experiments, and is being commissioned during the Phase-0 experiments at FAIR, between 2018 and 2020. It surrounds the reaction target in a segmented configuration with 2432 detection units made of long CsI(Tl) finger-shaped scintillator crystals. CALIFA has a 10 year intended operational lifetime as the R3B calorimeter, necessitating measures to be taken to ensure enduring performance. In this paper we present a systematic study of two groups of 6 different detection units of the CALIFA detector after more than four years of operation. The energy resolution and light output yield are evaluated under different conditions. Tests cover the aging of the first detector units assembled and investigates recovery procedures for degraded detection units. A possible reason for the observed degradation is given, pointing to the crystal-APD coupling.

Assessment of the SPIDER beam features by diagnostic calorimetry and thermography.

The full-size ITER ion source prototype SPIDER (Source for the Production of Ions of Deuterium Extracted from a Radio frequency plasma) has recently started beam operation, whose objective is to produce 100 keV, 60 A hydrogen negative ions for 1 h. The source is presently operated in the volume regime, and the beam power is consequently limited. In such a configuration, the high resolution calorimeter STRIKE (Short-Time Retractable Instrumented Kalorimeter Experiment), even though uncooled, may be used instead of the SPIDER beam dump without limiting the beam-on time. STRIKE is formed by unidirectional carbon fiber-carbon matrix (CFC) composite tiles that are exposed to the beam while their temperature is recorded by using two infra-red cameras. This setup, thanks to the moderate broadening of the temperature profile guaranteed by the anisotropy of CFC, allows for the determination of detailed features of the beam current distribution (spatial resolution is about 2 mm). Furthermore, positively biasing the CFC tiles permits a direct electrical measurement of the negative ion beam current. Besides the total beam current and beam uniformity, which can be retrieved both by calorimetry and electrical measurement, beamlet divergence and deflection can be determined by infra-red thermography. This contribution describes the characterization of the SPIDER negative ion beam as a function of the source and accelerator parameters by means of the diagnostic calorimeter STRIKE in the volume regime.

The PANDA Detector at FAIR

PANDA is a fixed-target experiment that is going to address a wide range of open questions in the hadron physics sector by studying the interactions between antiprotons with high momenta and a stationary proton target. The PANDA detector is currently under construction and will be situated in the HESR that is a part of the future FAIR accelerator complex on the area of the GSI Helmholtzzentrum f¨ur Schwerionenforschung in Darmstadt. The key features of the detector are: the precise tracking in strong magnetic fields, excellent particle identification, and high-resolution calorimeters.

Direct electrocaloric, structural, dielectric, and electric properties of lead-free ferroelectric material Ba0.9Sr0.1Ti1-xSnxO3 synthesized by semi-wet method

By using the semi-wet synthesis method, lead-free ferroelectric materials Ba0.9Sr0.1Ti1-xSnxO3 with x = 0, 0.02, 0.05, and 0.10 (abbreviated as BSTS) were prepared and their structural, electric and electrocaloric properties were investigated. The X-ray diffraction (XRD) patterns show that the samples calcined at 950 °C have well crystallized into perovskite structure suggesting the substitution of Ti4+ by Sn4+ in BST lattice. With increasing content of Sn, the enhancement of the dielectric permittivity was observed for (0 ≤ x ≤ 0.05) and the ferroelectric transition temperature (TC) was found to shift towards the room temperature (TC = 20 °C for x = 0.10). Direct measurements of the electrocaloric effect (ECE) were performed on all samples by using the high-resolution calorimeter. It is found that Ba0.9Sr0.1Ti0.95Sn0.05O3 exhibits a high ECE temperature change of ΔTEC = 0.188 K at an applied electric field of only 7 kV/cm. Impedance spectrum analysis of all the samples performed in the temperature range of 300–360 °C reveals the existence of two relaxation contributions related to the grain and grain boundaries that are well separated in frequency. Activation energies of conduction and relaxation processes were deduced for both contributions in order to determine the conduction mechanism of the studied compositions.

Nuclear spallation in active galaxies

A number of works point to the presence of narrow emission features at unusual energies in the X-ray spectra of active galactic nuclei (AGN) or to potentially low iron abundances as possible evidence for the spallation of iron. With the imminence of high-resolution calorimeter spectroscopy, the potential to test spallation models in astrophysical sources will soon be possible. Previously determined nuclear spallation reactions of Fe are recalculated making use of improved total inelastic and partial reaction cross sections that result in different absolute and relative abundances of the main spallation elements Mn, Cr, V, and Ti. The effects of ionisation and dynamics near the black hole are examined in simulated spectra with CCD and calorimeter (i.e. Hitomi) resolution. With high-resolution, differences in relative abundances and ionisation should be detectable if spallation is originating at large distances from the black hole (e.g. torus or disc wind) where blurring is not significant. If spallation were occurring in the inner accretion disc, it would likely be undetected as blurring effects would cause significant blending of spectral features.

Investigation of Electronic States by Angle-Resolved Magnetic Heat Capacity Measurements by Using High-Resolution Calorimeters Designed for Small Amounts of Samples

Investigation of Electronic States by Angle-Resolved Magnetic Heat Capacity Measurements by Using High-Resolution Calorimeters Designed for Small Amounts of Samples

Parallelized, real-time, metabolic-rate measurements from individual Drosophila

Significant recent evidence suggests that metabolism is intricately linked to the regulation and dysfunction of complex cellular and physiological responses ranging from altered metabolic programs in cancers and aging to circadian rhythms and molecular clocks. While the metabolic pathways and their fundamental control mechanisms are well established, the precise cellular mechanisms underpinning, for example, enzymatic pathway control, substrate preferences or metabolic rates, remain far less certain. Comprehensive, continuous metabolic studies on model organisms, such as the fruit fly Drosophila melanogaster, may provide a critical tool for deciphering these complex physiological responses. Here, we describe the development of a high-resolution calorimeter, which combines sensitive thermometry with optical imaging to concurrently perform measurements of the metabolic rate of ten individual flies, in real-time, with ~100 nW resolution. Using this calorimeter we have measured the mass-specific metabolic rates of flies of different genotypes, ages, and flies fed with different diets. This powerful new approach enables systematic studies of the metabolic regulation related to cellular and physiological function and disease mechanisms.

Multilayer 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3 elements for electrocaloric cooling

Electrocaloric (EC) cooling elements in the form of multilayers (MLs) were prepared. The elements consist of five layers of the relaxor-ferroelectric 0.9Pb(Mg1/3Nb2/3)O3–0.1PbTiO3, about 60μm thick, with internal platinum electrodes and exhibiting a dense, uniform microstructure with a grain size of 1.7μm. The largest temperature change ΔTEC of 2.26K was achieved at an electric field (E) of 100kVcm−1 and at 105°C, measured by a high-resolution calorimeter. These results agree well with the indirect measurements. The EC coefficient, ΔTEC/ΔE, obtained for the MLs, is similar to the value obtained for bulk ceramics of the same composition. The ΔTEC values above 2K over a broad temperature range from 75 to 105°C make the ML elements suitable candidates for EC cooling devices at significantly lower voltages than bulk ceramic plates with comparable dimensions and mass.

TH-CD-201-09: High Spatial Resolution Absorbed Dose to Water Measurements Using Optical Calorimetry in Megavoltage External Beam Therapy

Purpose: To develop and implement a high spatial resolution calorimeter methodology to measure absorbed dose to water (ADW) using phase shifts (PSs) of light passing through a water phantom and to compare measurements with theoretical calculations. Methods: Radiation-induced temperature changes were measured using the PSs of a He-Ne laser beam passing through a (10×10×10) cm3 water phantom. PSs were measured using a Michelson interferometer and recording the time-dependent fringe patterns on a CCD camera. The phantom was positioned at the center of the radiation field. A Varian 21EX was used to deliver 500 MU from a 9 MeV beam using a (6×6) cm2 cone. A 127cm SSD was used and the PSs were measured at depths ranging from of 1.90cm to 2.10cm in steps of 0.05cm by taking profiles at the corresponding rows across the image. PSs were computed by taking the difference between pre- and post-irradiation image frames and then measuring the amplitude of the resulting image profiles. An amplitude-to-PS calibration curve was generated using a piezoelectric transducer to mechanically induce PSs between 0.05 and 1.50 radians in steps of 0.05 radians. The temperature dependence of the refractive index of water at 632.8nm was used to convert PSs to ADW. Measured results were compared with ADW values calculated using the linac output calibration and commissioning data. Results: Milli-radian resolution in PS measurement was achieved using the described methodology. Measured radiation-induced PSs ranged from 0.10 ± 0.01 to 0.12 ± 0.01 radians at the investigated depths. After converting PSs to ADW, measured and calculated ADW values agreed within the measurement uncertainty. Conclusion: This work shows that interferometer-based calorimetry measurements are capable of achieving sub-millimeter resolution measuring 2D temperature/dose distributions, which are particularly useful for characterizing beams from modalities such as SRS, proton therapy, or microbeams.

Electrocaloric properties of 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 ceramics with different grain sizes

We have investigated the electrocaloric (EC) properties of the ceramic 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3. A variety of samples with different median grain sizes, i.e., 1.0, 2.2 and 4.0 μm, and relative densities of about 96% were prepared using atmospheric sintering at 1200oC for 2, 8 and 16 h. The ceramic material with a median grain size of 2.2 μm exhibited the highest value for the EC temperature change, i.e., 1.27 K at 60 kV cm−1, measured with a high-resolution calorimeter. This value is 25 and 19% higher than the value for the ceramics with the finer and the coarser grains, respectively.

Development of a forward calorimeter system for the STAR experiment

We present results of an R&D program to develop a forward calorimeter system (FCS) for the STAR experiment at the Relativistic Heavy Ion Collider at BNL. The FCS is a very compact, compensated, finely granulated, high resolution calorimeter system being developed for p+p and p+A program at RHIC. The FCS prototype consists of both electromagnetic and hadron calorimeters. The electromagnetic portion of the detector is constructed with W powder and scintillation fibers. The hadronic calorimeter is a traditional Pb/Sc-plate sandwich design. Both calorimeters were readout with Hamamatsu MPPCs. A full- scale prototype of the FCS was tested with a beam at FNAL in March 2014. We present details of the design, construction technique and performance of the FCS prototype during the test run at FNAL.

Future liquid Argon detectors

The Liquid Argon Time Projection Chamber offers an innovative technology for a new class of massive detectors for rare-event detection. It is a precise tracking device that allows three-dimensional spatial reconstruction with mm-scale precision of the morphology of ionizing tracks with the imaging quality of a “bubble chamber”, provides dE/dx information with high sampling rate, and acts as high-resolution calorimeter for contained events. First proposed in 1977 and after a long maturing process, its holds today the potentialities of opening new physics opportunities by providing excellent tracking and calorimetry performance at the relevant multi-kton mass scales, outperforming other techniques. In this paper, we review future liquid argon detectors presently being discussed by the neutrino physics community.

Study of jet quenching using dijets in PbPb collisions with CMS

Jets are an important tool to probe the hot, dense medium that is produced in ultra-relativistic heavy ion collisions. The large collision energy at the LHC provides copious production of dijets with energies that can be cleanly identified above the heavy ion background. The multipurpose CMS detector is well designed to measure these hard scattering processes with its high resolution calorimeters and high precision silicon tracker. Jet quenching is observed by a significant imbalance of dijet transverse momentum in PbPb collisions at TeV. The fraction of unbalanced dijets is found to increase strongly with increasing collision centrality. The dijet imbalance persists to the highest jet momenta studied. The redistribution of the quenched jet energy is studied using the transverse momentum balance of charged tracks projected onto the direction of the leading jet. In contrast to pp collisions, a large fraction of the momentum balance for asymmetric jets is found to be carried by low momentum particles at large angular distance from the jet axis.

Jet measurements by the CMS experiment in pp and Pb–Pb collisions

The energy loss of fast partons traversing the strongly interacting matter produced in high-energy nuclear collisions is one of the most interesting observables to probe the nature of the produced medium. The multipurpose compact muon solenoid (CMS) detector is well designed to measure these hard scattering processes with its high-resolution calorimeters and high precision silicon tracker. In central Pb–Pb collisions, a center-of-mass energy of 2.76 TeV parton energy loss is observed as a significant dijet transverse momentum imbalance, when comparing to a reference distribution corresponding to pp collisions at the same energy. To gain further understanding of the parton energy loss mechanism, the redistribution of the quenched jet energy was studied using the transverse momentum balance of charged tracks projected onto the direction of the leading jet. In contrast to pp collisions, a large fraction of the momentum balance for asymmetric dijets is found to be carried by low momentum particles at large angular distance to the axis of the recoiling jet. Further, the fragmentation functions for leading and subleading jets were reconstructed and were found to be unmodified compared to measurements in pp collisions. The results yield a detailed picture of parton propagation in the hot QCD medium.

Influence of the critical point on the electrocaloric response of relaxor ferroelectrics

The electrocaloric effect (ECE), i.e., the conversion of electric energy into heat, is of great importance for application in new generation cooling or heating devices that would be friendlier to the environment. Here, utilizing direct measurements of the ECE change of the temperature ΔT via a high resolution calorimeter, we study the ECE as a function of the magnitude of the electric-field step E in the vicinity of the critical point in several bulk relaxor ferroelectric ceramic systems. Relatively large ΔT of ∼2 to 3 K were obtained at modest fields of 90 kV/cm, even in the case of ceramic materials. The effective responsivity ΔT/E as a function of the electric field shows a characteristic peak near the critical point, which demonstrates the importance of proximity to the critical point for the enhancement of the electrocaloric effect. Experimental results are in good agreement with the theoretical calculations based on the spherical random-bond random-field model.

Effect of Cold Rolling on Thermal Stability of Zr<sub> 55</sub> Al<sub>10</sub>Ni<sub>5</sub>Cu<sub>30</sub> Bulk Metallic Glass

The effect of cold rolling on thermal stability of bulk Zr55Al10Ni5Cu30 metallic glass at room temperature had been investigated by means of X-ray diffractometer, high-resolution transmission electron microscope and differential scanning calorimeter. A number of the cold rolling processes were carried out to obtain different thickness reduction in specimens with the same original size. The XRD patterns of cold rolled specimens with thickness reduction up to 95% showed no clear difference with that of completely amorphous specimens. The relationship of the deformation with the thermal parameters of cold rolled specimen indicates that with the increase of thickness reduction, the glass transition temperature decreases obviously and the crystallization onset temperature and peak temperature decreases slightly. At the same time, the enthalpy of crystallization peak keeps almost constant during rolling. These results have revealed that cold rolling deformation has an apparently effect on the glass transition process but slightly effect on the crystallization process of Zr55Al10Ni5Cu30 BMG.