Dual-readout Calorimeter Research Articles

Simulation of a capillary tube, fibre dual-readout calorimeter in DD4hep

Over the past years the dual-readout method for calorimetry, which exploits complementary information from Scintillation and Cherenkov channels, has emerged as candidate to fulfil the requirements for precision physics at future circular lepton colliders. While the dual-readout approach has been tested experimentally quite extensively, this type of calorimeter has never been used in an experiment at a collider. In recent years dedicated studies in simulation have investigated various detector geometries based on a fibre dual-readout calorimeter. One variation of the geometry, relying on capillary tubes, promises easy assembly with excellent geometrical accuracy at a moderate cost. In these proceedings, we present the status and latest results from a full 4π detector geometry simulation in DD4hep. The simulation is used to estimate the performance of a dual-readout calorimeter for single electromagnetic and hadronic particles. The results for the dual-readout technique show an improvement in energy resolution for both electromagnetic and hadronic showers, with respect to single channel measurements.

Exposing a dual-readout fibre calorimeter to electron beams, in preparation for HiDRa: High-resolution calorimeter for [formula omitted] colliders

Among the proposed accelerators for the post-LHC era are the Future Circular Collider (FCC) and the Circular Electron–Positron Collider (CEPC). Both projects would take advantage of the clean environment and low radiation damage of electron–positron collisions, providing the highest precision studies of electroweak and Higgs physics. The relatively high branching fraction of W, Z and Higgs bosons into hadronic jets makes the precise measurements of these objects an essential aspect on detector development for experiments at future collider facilities. One of the most promising calorimetry techniques for improved hadron energy reconstruction is the dual-readout method, which exploits signals from two different physics processes to correct for the fem of hadron showers, therefore boosting the standalone calorimeter performance. The usage of compact photosensors (e.g. Silicon PhotoMultipliers) for the readout enables a very fine segmentation, opening to particle-flow and advanced neural networks software reconstruction of events. In this contribution, the results of testing a small-scale dual-readout calorimeter prototype, characterised by a mixed PMT and SiPM readout solution, with an electron beam at the CERN SPS facility in the energy range [10, 120] GeV are presented. It follows the description of a larger prototype of the same type, currently under construction in the context of the INFN HiDRa project, that will be large enough to fully contain hadron showers. The design, construction technique and expected performance, as estimated through a Geant4 simulation parameterised on the previous prototype, are presented.

Development of particle flow algorithms based on Neural Network techniques for the IDEA calorimeter at future colliders

IDEA (Innovative Detector for an Electron-positron Accelerator) is an innovative general-purpose detector concept, designed to study electron-positron collisions at future e+e− circular colliders. The detector will be equipped with a dual read-out calorimeter able to measure separately the hadronic component and the electromagnetic component of the showers initiated by the impinging hadrons. Particle flow algorithms (PFAs) have become the paradigm of detector design for the high energy frontier and this work focuses on a project to build a particle flow algorithm for the IDEA detector using Machine Learning (ML) techniques. ML is used for particle reconstruction and identification profiting of the high granularity of the fiber-based dual-readout calorimeter. Neural Networks (NN) are built for electron reconstruction inside the calorimeter. The performance of several NN architectures is shown, with particular attention to the layer setup and the activation function choices. The performance is evaluated on the energy resolution function of the reconstructed particles. The algorithm is trained using both parallel CPUs and GPU, and the time performance and the memory usage of the two approaches are systematically compared.

Exposing a fibre-based dual-readout calorimeter to a positron beam

A prototype of a dual-readout calorimeter using brass capillary tubes surrounding scintillating and clear plastic optical fibres was tested using beams of particles with energies between 10 and 100 GeV produced by the CERN SPS. The scope of the test was to characterise the performance of the tube-based detector response to positrons in terms of response linearity, energy resolution, and lateral granularity. After calibrating the detector and processing the output signal to correct for the energy dependency on the particle impact point, the linearity of the measurement was found to be better than 1%. The response to positron was compared to that predicted by a Geant4-based simulation, finding good agreement both in terms of energy resolution and shower profile. These results confirm the validity of the tube-based mechanical option and SiPM readout as a promising one for future developments.

Simulation study of Dual-Readout Calorimeter for a forward calorimeter at the Electron-Ion Collider

The Electron-Ion Collider (EIC) is a future particle accelerator to be built at the Brookhaven National Laboratory, and the primary purpose of experiments at the EIC is to resolve the question of partonic structure of nucleons and nuclei. To achieve the physics goals of the EIC, a hadron calorimeter of high energy resolution is required at forward rapidity. A Dual-readout Calorimeter (DRC) which has been developed for future collider experiments is considered as an upgrade option of the forward hadron calorimeter for the ECCE experiment at the EIC. The DRC consisting of two types of optical fiber, Cherenkov and Scintillation fibers, can achieve high energy resolution by measuring a fraction of electromagnetic shower in a hadronic shower. A performance study of DRC for the EIC such as geometry, material, and energy resolution is ongoing based on the existing simulation framework for high energy experiments, and the DRC simulation details will be transported to the EIC simulation framework. In this presentation, we will introduce the simulation study of the DRC for the EIC.

The [formula omitted]-RWELL technology for the preshower and muon detectors of the IDEA detector

The IDEA detector concept has been designed to operate at a future large circular e+e− collider, like FCC-ee or CEPC. The IDEA detector has an innovative design with a central tracker enclosed in a superconducting solenoidal magnet. Going outwards, a preshower system followed by a dual readout calorimeter is foreseen. In the iron yoke, that closes the magnetic field, are then located three stations of muon detectors. The preshower and muon detectors are based on the μ-RWELL technology that inherits the best characteristics of the GEM, in particular the layout of the amplification stage, and Micromega detectors, that inspired the presence of a resistive stage. To profit of the industrial production capabilities of this technology, a modular design has been adopted for both systems: the μ-RWELL tile will have an active area of 50 × 50 cm2, but with a pitch between the readout strips of 400μm for the preshower and about 1 mm for the muon system. Other requirements are: a spatial resolution of the order of 100μm for the preshower and a reasonable total number of front-end channels for the muon system. To optimize the resistivity and the strip pitch, we have built a set of prototypes with active area of 5 × 40 cm2 and 40 cm long strips. The DLC resistivity is ranging from 10 to 80 MΩ/□. All these detectors have been exposed in October 2021 to a muon beam at the CERN SPS. The very positive results obtained pave the way for a completely new and competitive MPGD tracking device for high energy physics experiments.

SiPMs for Dual-Readout Calorimetry

A new fibre-sampling dual-readout calorimeter prototype has been qualified on beam at two facilities (DESY and CERN) using electrons from 1 to 100 GeV. The prototype was designed to almost fully contain electromagnetic showers and a central module (highly granular readout) was equipped with 320 Silicon Photomultipliers (SiPMs) spaced by 2 mm and individually read out. The test beams performed in 2021, allowed to qualify the readout boards used to operate the SiPMs, to define the calibration procedure and to measure the light yield for scintillating and Cherenkov signals produced by the shower development. This paper reports the first results obtained with the highly granular readout and discusses the ongoing R&D to address some open questions concerning the mechanical integration and the scalable readout scheme that will allow to build and operate the next prototype designed for hadronic showers containment.

Reconstruction of 3D Shower Shape with the Dual-Readout Calorimeter

The dual-readout calorimeter has two channels, Cherenkov and scintillation, that measure the fraction of an electromagnetic (EM) component within a shower by using different responses of each channel to the EM and hadronic component. It can measure the energy of EM and hadronic shower simultaneously—its concept inspired the integrated design for measuring both EM and hadronic showers, which left the task of reconstructing longitudinal shower shapes to the utilization of timing. We explore the possibility of longitudinal shower shape reconstruction using signal processing on silicon photomultiplier timing, and 3D shower shape by combining lateral and longitudinal information. We present a comparison between Monte Carlo (MC) and reconstructed longitudinal shower shapes from the simulation, and the application of 3D shower shapes associated with the dual nature of the calorimeter to identify electrons, hadrons, and hadronic punch-thru or muons.

Tau Lepton Identification With Graph Neural Networks at Future Electron–Positron Colliders

Efficient and accurate reconstruction and identification of tau lepton decays plays a crucial role in the program of measurements and searches under the study for the future high-energy particle colliders. Leveraging recent advances in machine learning algorithms, which have dramatically improved the state of the art in visual object recognition, we have developed novel tau identification methods that are able to classify tau decays in leptons and hadrons and to discriminate them against QCD jets. We present the methodology and the results of the application at the interesting use case of the IDEA dual-readout calorimeter detector concept proposed for the future FCC-ee electron–positron collider.

Particle flow with a hybrid segmented crystal and fiber dual-readout calorimeter

In the reconstruction of physics events at future e+e- colliders the calorimeter design has a crucial role in the overall detector performance. The reconstruction of events with many jets in their final state sets stringent requirements on the jet energy and angular resolutions. The energy resolution for jets with energy of about 45 GeV is required to be at the 4–5% level to enable an efficient separation of the W and Z boson invariant masses. We demonstrate in this paper how such a performance can be achieved by exploiting a particle flow algorithm tailored for a hybrid dual-readout calorimeter made of segmented crystals and fibers. The excellent energy resolution and linearity of such calorimeter for both photons and neutral hadrons (3%/√E and 26%/√E, respectively), inherent to the homogeneous crystals and dual-readout technological choices, provides a powerful handle for the development of a new approach for particle identification and jet reconstruction. While the dual-readout particle flow algorithm (DR-PFA) presented in this paper is at its early stage of development, it already demonstrates the potential of a hybrid dual-readout calorimeter for jet reconstruction by improving the jet energy resolution with respect to a calorimeter-only reconstruction from 6.0% to about 4.5% for 45 GeV jets.

Characterization of mixed Bi4(Ge[formula omitted]Si[formula omitted])3O12 for crystal calorimetry at future colliders

Bismuth germanate (BGO) is a well known high density scintillating material widely used in many applications such as high energy physics and medical imaging. Bismuth silicate (BSO) features properties similar to BGO in terms of stopping power and Cherenkov photon yield with a lower scintillation light output but faster decay time, thus being more attractive for applications in high-rate environments. Mixed crystals such as Bi4(GexSi1−x)3O12 (BGSO, with x varying from 0 to 1) make it possible to optimize decay time and light yield based on the detector needs.A characterization campaign of the optical and scintillation properties of two sets of BGSO mixed crystals with Ge fraction varying from 0 to 100% was performed. A coincidence time resolution (CTR) at 511 keV of 208 ±2 ps FWHM was measured for a 2 × 2 × 3 mm3 pixel with 40% Ge, while the optimum value obtained for the effective decay time is 49.9 ±1.8 ns for a 6 × 6 × 0.7 mm3 plate-shaped sample with 30% Ge. Furthermore the smallest slow decay time component achieved is 101 ±2 ns and is obtained for the plate-shaped sample with 30% Ge, while the largest is 236 ±5 ns for a pure BGO sample with the same geometry.In addition we demonstrated the possibility to efficiently separate the Cherenkov and scintillation light produced in a pure BSO sample. Such a technique could be exploited in a crystal-based dual-readout calorimeter to improve the energy resolution for hadronic showers and jets.

Present status and perspective of dual-readout calorimetry for future accelerators

Dual-readout calorimetry is a calorimetric technique able to overcome the noncompensation limit by simultaneously detecting scintillation and Cherenkov light. Scintillating photons provide a signal related to the energy deposition in the calorimeter by all ionising particles while Cherenkov photons provide a signal almost exclusively related to the electromagnetic component in the hadronic shower. Fluctuations among the electromagnetic and non-electromagnetic component of hadronic induced showers represent the major limit to reach resolutions needed in experiments at future leptonic colliders. In a dual-readout calorimeter, by looking at the two independent signals, it is possible to measure, event by event, the electromagnetic fraction and to correctly reconstruct the primary hadron energy. Applications of the dual-readout method in fiber-sampling calorimetry have been shown to be able to provide single hadron detection with an energy resolution around [Formula: see text], electromagnetic resolution around [Formula: see text], excellent particle identification capability, resulting in one of the most promising option for future leptonic colliders. Status-of-art of the dual-readout calorimetry, as well as, perspective in the developments toward scalable solution for [Formula: see text] detectors are presented in this paper. This includes, study on the material choice, SiPM readout of the fibers, possible segmentation of the fibers to enhance particle ID capability.

Dual-readout calorimetry

We summarize the fundamental aspects of dual-readout calorimetry, a calorimetric technique able to overcome the non-compensation problem by means of two independent scintillation and Cherenkov light signals detection. The expected ultimate energy resolution for single-hadron detection, together with the excellent particle identification capability, makes a dual-readout fiber calorimeter one of the most promising options for future leptonic colliders. In this paper, we include the main benefits of a new silicon photomultiplier-based readout system that allows to sample showers with an unprecedented spatial resolution.

First test-beam results obtained with IDEA, a detector concept designed for future lepton colliders

IDEA (Innovative Detector for Electron–positron Accelerators) is a detector concept designed for a future leptonic collider operating as a Higgs factory. It is based on innovative detector technologies developed over years of R&D. In September 2018, prototypes of the proposed sub-detectors have been tested for the first time on a beam line at CERN. The preliminary results from this test of a full slice of the IDEA detector and standalone measurements of dual read-out calorimeter prototypes are presented.

Linearity response measurement of a SiPM-based dual-readout calorimeter for future leptonic colliders

A dual-readout fibre sampling calorimeter module, based on Silicon Photomultiplier readout, was developed and tested on beam in 2016 and 2017. This test completed the proof-of-concept but also revealed a non-linear response to the scintillation light. In 2018, the signal linearity was studied after the interposition of a yellow filter between the scintillating fibres and the sensors. This paper reports the latest results on the module performance, highlighting as well the key and potentially critical parameters and the adopted solutions.

Dual-readout calorimetry, an integrated high-resolution solution for energy measurements at future electron–positron colliders

Future circular electron–positron colliders operating at s=90, 160, 240 and 350 GeV as Z, W, H and t factories will demand experiments with superior momentum and energy resolution for all the possible final-state particles produced. The IDEA Detector aims at satisfying these requests by exploiting an ultra-light drift chamber as the largest central tracker and a dual-readout fiber calorimeter for both electromagnetic and hadronic energy measurements. In this paper I review the dual-readout calorimeter baseline choices, as well as the related R&D work.

Development of a Silicon Photomultiplier based dual readout calorimeter: The pathway beyond the proof-of-concept

A first dual-readout fibre calorimeter readout with Silicon Photomultipliers was designed, constructed and tested on beam. This first test completed the proof-of-concept and pointed out some issues to be address in future beam tests. Possible solutions and strategies to overcome these challenges are summarized in this paper.

Hadron detection with a dual-readout fiber calorimeter

In this paper, we describe measurements of the response functions of a fiber-based dual-readout calorimeter for pions, protons and multiparticle “jets” with energies in the range from 20 to 180 GeV. The calorimeter uses lead as absorber material and has a total mass of 1350 kg. It is complemented by leakage counters made of scintillating plastic, with a total mass of 500 kg. The effects of these leakage counters on the calorimeter performance are studied as well. In a separate section, we investigate and compare different methods to measure the energy resolution of a calorimeter. Using only the signals provided by the calorimeter, we demonstrate that our dual-readout calorimeter, calibrated with electrons, is able to reconstruct the energy of proton and pion beam particles to within a few percent at all energies. The fractional widths of the signal distributions for these particles (σ∕E) scale with the beam energy as 30%∕E, without any additional contributing terms.

Growth and characterization of Ce-doped YAG and LuAG fibers

Undoped and Ce-doped Lu3Al5O12 (LuAG) and Y3Al5O12 (YAG) single crystal fibers were grown by the micro-pulling down technique (μ-PD) with a purpose to fit the design of new dual-readout calorimeter planned to operate in future experiences of high energy physics. Fibers up to 20 cm in length and 1 mm in diameter were grown along [111] direction. Based on the measurements of the attenuation length along the fibers, the growth conditions to improve the fibers quality were selected. Our results showed that the grown fibers have the capability to be used for future detectors.

The small-angle performance of a dual-readout fiber calorimeter

The performance of the RD52 dual-readout calorimeter is measured for very small angles of incidence between the 20GeV electron beam particles and the direction of the fibers that form the active elements of this calorimeter. The calorimeter response is observed to be independent of the angle of incidence for both the scintillating and the Čerenkov fibers, whereas significant differences are found between the angular dependence of the energy resolution measured with these two types of fibers. The experimental results are on crucial points at variance with the predictions of GEANT4 Monte Carlo simulations.