Resolution Calorimeter Research Articles

Towards the construction of the Mu2e electromagnetic calorimeter at Fermilab

Mu2e will search for the Charge Lepton Flavor Violating (CLFV) conversion of a muon into an electron in the field of a nucleus. A clean discovery signature is provided by the mono-energetic conversion electron (Ee = 104.96 MeV). If no events are observed, Mu2e will set a limit on the ratio between the conversion and the nuclear capture rate below 3 × 10−17 (at 90% C.L.). In order to confirm that the observed candidate is an electron, the calorimeter resolution requirements are to provide Eres < 10%, Tres < 500 ps for 100 MeV electrons while working in vacuum and in a high radiation environment and high magnetic field. The calorimeter is made of two annular aluminum disks, each one filled with 674 pure CsI crystals read out by SiPMs. A sophisticated mechanics and cooling system has been developed to support the crystals and cool the sensors. Radiation hard analog and fast digital electronics have been developed. In this paper the QC tests performed on the produced components and the construction status are reported, as well as the results obtained on the large size prototype with test beam data and at a cosmic ray test stand.

FASER’s Electromagnetic Calorimeter Test Beam Studies

FASER, or the Forward Search Experiment, is a new experiment at CERN designed to complement the LHC’s ongoing physics program, extending its discovery potential to light and weakly interacting particles that may be produced copiously at the LHC in the far-forward region. New particles targeted by FASER, such as long-lived dark photons or axion-like particles, are characterised by a signature with two oppositely charged tracks or two photons in the multi-TeV range that emanate from a common vertex inside the detector. The full detector was successfully installed in March 2021 in an LHC side tunnel 480 m downstream from the interaction point in the ATLAS detector. FASER is planned to be operational for LHC Run 3. The experiment is composed of a silicon-strip tracking-based spectrometer using three dipole magnets with a 20 cm aperture, supplemented by four scintillator stations and an electromagnetic calorimeter. The FASER electromagnetic calorimeter is constructed from four spare LHCb calorimeter modules. The modules are of the Shashlik type with interleaved scintillator and lead plates that result in 25 radiation lengths and 1% energy resolution for TeV electromagnetic showers. In 2021, a test beam campaign was carried out using one of the CERN SPS beam lines to set up the calibration of the FASER calorimeter system in preparation for physics data taking. The relative calorimeter response to electrons with energies between 10 and 300 GeV, as well as high energy muons and pions, has been measured under various high voltage settings and beam positions. The measured calorimeter resolution, energy calibration, and particle identification capabilities 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.

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.

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.

Low-temperature immobilization of water in Antarctic Turgidosculum complicatulum and in Prasiola crispa. Part I. Turgidosculum complicatulum.

The studies of low-temperature immobilization of bound water in Antarctic lichenized fungus Turgidosculum complicatulum were performed using 1H NMR and DSC over a wide range of thallus hydration. 1H NMR free induction decays were decomposed into a solid component well described by the Gaussian function and two exponentially decaying components coming from a tightly bound water and from a loosely bound water fraction. 1H NMR spectra revealed one averaged mobile proton signal component. 1H NMR measurements recorded in time and in frequency domain suggest the non-cooperative bound water immobilization in T. complicatulum thallus. The threshold of the hydration level estimated by 1H NMR analysis at which the cooperative bound water freezing was detected was Δm/m0 ≈ 0.39, whereas for DSC analysis was equal to Δm/m0 = 0.375. Main ice melting estimated from DSC measurements for zero hydration level of the sample starts at tm = -(19.29 ± 1.19)°C. However, DSC melting peak shows a composed form being a superposition of the main narrow peak (presumably melting of mycobiont areas) and a broad low-temperature shoulder (presumably melting of isolated photobiont cells). DSC traces recorded after two-hour incubation of T. complicatulum thallus at -20 °C suggest much lower threshold level of hydration at which the ice formation occurs (Δm/m0 = 0.0842). Presumably it is a result of diffusion induced migration of separated water molecules to ice microcrystallites already present in thallus, but still beyond the calorimeter resolution.

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.

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.

CMS Hadron Forward Calorimeter Phase I Upgrade Status

The CMS Hadronic Forward Calorimeter has undergone upgrade maintenance during the LHC Long Shutdown 1. The Hamamatsu R7525 PMTs have been replaced with Hamamatsu R7600U-200-M4 PMTs, which have thinner window glass that reduces window- hit events. The R7600 PMTs also have multi-anode readout feature to further enable discrimination of window-hits while also allowing the recovery of true signal energy. Higher quantum efficiency of the R7600 PMTs improves calorimeter resolution. The new PMTs were tested and calibrated; new PMT baseboards were designed and tested, and can be configured to readout 1, 2, or 4 anodes of the R7600. New radiation hard (100Gy) QIE front-end electronics were designed for reading out the new PMTs and include a TDC with < 800ps resolution. New back-end electronics based on the microTCA industrial standard have been tested.

Microstructural characterisation and microhardness distribution of HVOF sprayed WC–10Co–4Cr coating

The aim of this work was to study the detailed microstructures, thermostability and microhardness distribution of high velocity oxygen fuel sprayed WC–10Co–4Cr coating using X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy, differential scanning calorimeter and high resolution transmission electron microscope. The coating has a dense structure and is well bonded to the substrate. The coating is mainly composed of WC phase and W2C phase. Owing to the high cooling rates of molten droplets and the multicomponent system of feedstock powder, amorphous phase is obtained in the coating. The crystallisation temperature of the amorphous phase is 651°C. The Weibull analysis of Vickers microhardness of the coating exhibits a bimodal distribution under indentation load of 300 g and a monomodal distribution under indentation load of 100 g. Such distribution is attributed to the presence of the poorly bonded splats and pores within the coating.

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.

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.

J054062 MEMSセンサを用いた高感度カロリメータの研究([J05406]マイクロ・ナノスケールの熱流体現象(6))

Cells and microorganisms always generate metabolic heat as long as they are alive. So, total biological activity can be measured through the observation of metabolic heat at non-invasive and non-destructive, which is referred as "Bio-calorimetry". With downsizing and improvement in sensitivity of Calorimeters, the bio-calorimetry is expected to contribute in the medical, pharmacy and biotechnology. To use the MEMS (Micro Electro Mechanical System) technology, a bio-calorimetry can be measured a small heat generation. Therefore, we intended to development of high sensitivity and high resolution calorimeter with the MEMS technology. In this study, the batch type calorimeter with MEMS thermopile sensor was made, and its performance and thermal monitoring of Yeast metabolism were tested. As a result, the calorimeter evaluated a sensitivity of 2.6 V/W, a thermal noise equivalent to 23nW.For the thermal monitoring of the Yeast, the metabolic heat generation over 20 nW level was measured. In addition, we reported a flow type calorimeter with MEMS thermopile sensor for studying a biological response to a chemical stuff.

Cerenkov emission as a positive tag of double beta decays in bolometric experiments

Active background reduction in high resolution calorimeters is a promising approach to achieve ultimate sensitivity in neutrinoless double beta decay experiments. We propose Cerenkov emission from beta rays in bolometric crystals as a viable alternative to scintillation. This novel approach could broaden the range of materials of interest for calorimetric searches of the double beta decay. We discuss the optical properties of TeO2 crystals, as a show case.

Microstructure refinement and magnetic properties enhancement of nanocrystalline Nd12.3Fe81.7B6.0 ribbons by addition of Zr

Effects of Zr addition and annealing treatment on the formation, microstructure and magnetic properties of Nd12.3Fe81.7−x Zr x B6.0 (x=0−3.0) ribbons melt-spun and annealed have been systematically investigated by means of vibrating sample magnetometer (VSM), differential scanning calorimeter (DSC), X-ray diffraction (XRD), and high resolution scanning electron microscopy (HRSEM). Phase analysis reveals that Nd2Fe14B is single-phase material. It has been found that the intrinsic coercivity H ci of the optimally processed Nd12.3Fe81.7−x Zr x B6.0 ribbons increases monotonically from 751.7 kA/m for x=0 to 1005.3 kA/m for x=3.0. The remanence polarization J r and maximum energy product (BH)max increase first with Zr addition, then slightly decrease with further increasing Zr content. Optimum magnetic properties with J r=1.041 T, H ci=887.5 kA/m and (BH)max=175.2 kJ/m3 have been achieved for the ribbons with x=1.5. The significant improvement of magnetic properties originates from the finer grains of the ribbons by introducing Zr.

The CDF level 2 calorimetric trigger upgrade

CDF II upgraded the calorimeter trigger to cope with the higher detector occupancy due to the increased Tevatron instantaneous luminosity ( ∼ 2.8 × 10 32 cm - 2 s - 1 ) . While the original system was implemented in custom hardware and provided to the L2 trigger a limited-quality jet clustering performed using a reduced resolution measurement of the transverse energy in the calorimeter trigger towers, the upgraded system provides offline-quality jet reconstruction of the full resolution calorimeter data. This allows to keep better under control the dependence of the trigger rates on the instantaneous luminosity and to improve the efficiency and purity of the trigger selections. The upgraded calorimeter trigger uses the general purpose VME board Pulsar, developed at CDF II and already widely used to upgrade the L2 tracking and L2 decision systems. A battery of Pulsars is used to merge and send the calorimeter data to the L2 CPUs, where software-implemented algorithms perform offline-like clustering. In this paper we review the design and the performance of the upgraded system.

Energy flow in a hadronic cascade: Application to hadron calorimetry

The hadronic cascade description developed in an earlier paper is extended to the response of an idealized fine-sampling hadron calorimeter. Calorimeter response is largely determined by the transfer of energy Eπ0 from the hadronic to the electromagnetic sector via π0 production. Fluctuations in this quantity produce the “constant term” in hadron calorimeter resolution. The increase of its fractional mean, fπ00=〈Eπ0〉/E, with increasing incident energy E causes the energy dependence of the π/e ratio in a noncompensating calorimeter. The mean hadronic energy fraction, fh0=1-fπ00, was shown to scale very nearly as a power law in E: fh0=(E/E0) m-1, where E0≈1GeV for pions, and m≈0.83. It follows that π/e=1-(1-h/e)(E/E0) m-1, where electromagnetic and hadronic energy deposits are detected with efficiencies e and h, respectively. If the mean fraction of fh0 which is deposited as nuclear gamma rays is fγ0, then the expression becomes π/e=1-(1-h′/e)(1-fγ0)(E/E0) m-1. Fluctuations in these quantities, along with sampling fluctuations, are incorporated to give an overall understanding of resolution, which is different from the usual treatments in interesting ways. The conceptual framework is also extended to the response to jets and the difference between π and p response.

Heavy ion physics with the CMS experiment at the LHC

The LHC will collide protons at √ s = 14.0 TeV and lead beams at √ SNN = 5.5 TeV as well as other AA and pA combinations. The physics program of the Compact Muon Solenoid (CMS) includes the study of heavy ion collisions. The collision energy, much higher than is available at RHIC, will allow the study the dense partonic system with very hard probes: heavy quarks and quarkonia with emphasis on the b and γ, W ± and Z 0 bosons, high p T jets, photons. The production of these particles is likely to be modified, relative to pp collisions, by the presence of the hot hadronic medium. The CMS detector consists of a 13 m long, 6 m diameter superconducting solenoid which provides a uniform 4T magnetic field. The silicon tracker and electromagnetic and hadronic calorimeters are located inside the magnet while the muon detector is outside. The high granularity, high resolution calorimeters will provide hermetic coverage for | η| ≤ 5.5, making CMS an ideal detector to study high p T nuclear phenomena.