Semi-Digital Hadronic CALorimeter Research Articles

Energy reconstruction of hadronic showers at the CERN PS and SPS using the Semi-Digital Hadronic Calorimeter

The CALICE Semi-Digital Hadronic CALorimeter (SDHCAL) is the first technological prototype in a family of high-granularity calorimeters developed by the CALICE Collaboration to equip the experiments of future lepton colliders. The SDHCAL is a sampling calorimeter using stainless steel for absorber and Glass Resistive Plate Chambers (GRPC) as a sensitive medium. The GRPC are read out by 1 cm× 1 cm pickup pads combined to a multi-electronics. The prototype was exposed to hadron beams in both the CERN PS and the SPS beamlines in 2015 allowing the test of the SDHCAL in a large energy range from 3 GeV to 80 GeV. After introducing the method used to select the hadrons of our data and reject the muon and electron contamination, we present the energy reconstruction approach that we apply to the data collected from both beamlines and we discuss the response linearity and the energy resolution of the SDHCAL. The results obtained in the two beamlines confirm the excellent SDHCAL performance observed with the data collected with the same prototype in the SPS beamline in 2012. They also show the stability of the SDHCAL in different beam conditions and different time periods.

Particle identification using Boosted Decision Trees in the Semi-Digital Hadronic Calorimeter prototype

The CALICE Semi-Digital Hadronic CALorimeter (SDHCAL) prototype using Glass Resistive Plate Chambers as a sensitive medium is the first technological prototype of a family of high-granularity calorimeters developed by the CALICE collaboration to equip the experiments of future leptonic colliders. It was exposed to beams of hadrons, electrons and muons several times in the CERN PS and SPS beamlines between 2012 and 2018. We present here a new method of particle identification within the SDHCAL using the Boosted Decision Trees (BDT) method applied to the data collected in 2015. The performance of the method is tested first with Geant4-based simulated events and then on the data collected by the SDHCAL in the energy range between 10 and 80 GeV with 10 GeV energy steps. The BDT method is then used to reject the electrons and muons that contaminate the SPS hadron beams. The rejection power of the new method is estimated to be as high as 99.0% for the muons and 99.4% for the electrons associated to a pion selection efficiency of about 95.0%.

Particle identification using Boosted Decision Trees in the semi-digital hadronic calorimeter

The CALICE Semi-Digital Hadronic CALorimeter (SDHCAL) prototype using Glass Resistive Plate Chambers as a sensitive medium is the first technological prototype in a family of high-granularity calorimeters developed by the CALICE collaboration to equip the experiments of future leptonic colliders. It was exposed to beams of hadrons, electrons and muons several times on the CERN PS and SPS beamlines in 2012, 2015 and 2016. We present here a new method of particle identification within the SDHCAL using the Boosted Decision Tree (BDT) method applied to the data collected in 2015. The performance of the method is tested first with GEANT4-based simulated events and then on the data collected in the SDHCAL in the energy range between 10 and 80 GeV with 10 GeV energy steps. The BDT method is then used to reject the electrons and muons which contaminate the SPS hadron beams.

APRIL: a novel Algorithm for Particle Reconstruction at ILC

The current developments for future electron-positron colliders are driven by the Particle Flow concept. In these developments, high granularity calorimeters play a central role. This presentation will focus on a new Particle Flow Algorithm (PFA) developed for high granularity calorimeters, and especially for the Semi-Digital Hadronic CALorimeter (SDHCAL) option of the International Large Detector (ILD) concept. The first PFA for ILD was PandoraPFA. This new PFA (APRIL) is based on the PandoraPFA Software Development Kit, but implements a different clustering inspired from the ARBOR PFA approach. This proceeding will describe briefly the APRIL algorithm and discuss its performance compared to that of PandoraPFA.

Energy reconstruction for a hadronic calorimeter using multivariate data analysis methods

The CALICE highly granular Semi-Digital Hadronic CALorimeter (SDHCAL) technological prototype provides rich information on the shape and structure of the hadronic showers. To exploit this information and to improve on the standard energy reconstruction method where only the total number of hits is used, we propose to use two methods based on MultiVariate data Analysis (MVA) techniques: the Multi-Layer Perceptron (MLP) and the Boosted Decision Trees with Gradient Boost (BDTG) . The two new methods achieve better energy linearity (Δ E/Ebeam ≤ 2%) with respect to the classic method ( Δ E/Ebeam ≤ 5%) and improve on the relative energy resolution. For instance, the MLP method achieves 6–7% relative improvement on the whole energy range when applied on samples of simulated π− events in the SDHCAL.

Multigap Resistive Plate Chamber read out by [formula omitted] pads with the NINO ASIC

The Multigap Resistive Plate Chamber (MRPC) is a possible candidate for the Semi-Digital Hadronic Calorimeter (SDHCAL). Two 4.5×20cm2 active area MRPCs have been built to study the time resolution using the NINO ASIC as front-end electronics. The granularity of the active area is provided by a 4 × 16 array of 1×1cm2 pick-up pads. Two different designs have been used for the two chambers: a six gas gap MRPC (6-gap MRPC) with a 220μm gap size and a ten gas gap MRPC (10-gap MRPC) with a 160μm gap size. An efficiency of 95% and 97% has been reached respectively. A time resolution of 50 ps for the 6-gap MRPC and 30 ps for the 10-gap MRPC has been achieved. The multiplicity study of this two MRPCs shows that a large fraction of the single hit is recorded in the events (71% for 6-gap MRPC and 64% for 10-gap MRPC).

Performance study of a large 1 [formula omitted] 1 m2 MRPC with 1 [formula omitted] 1 cm2 readout pads

A Semi-Digital Hadronic Calorimeter (SDHCAL) concept has been proposed for future leptonic collider experiments. The multigap resistive plate chamber (MRPC) is a candidate for the detector planes of this calorimeter. We have constructed three MRPCs of 1m × 1m size for tests of the SDHCAL. Two have 4 gas gaps and one has 5 gas gaps. To achieve high granularity for a calorimeter, the signals from the MRPC are readout by 1×1cm2 pads. The three MRPCs have similar design but the fishing line spacer has different configurations. All three MRPCs were successfully tested in the T10 test beam facility at CERN with a gas mixture of 95% C2H2F4 and 5% SF6. The efficiency and multiplicity of these chambers have been studied. All chamber reached around 94% efficiency at the proper operating voltage.

Tracking within Hadronic Showers in the CALICE SDHCAL prototype using a Hough Transform Technique

The high granularity of the CALICE Semi-Digital Hadronic CALorimeter (SDHCAL) provides the capability to reveal the track segments present in hadronic showers. These segments are then used as a tool to probe the behaviour of the active layers in situ, to better reconstruct the energy of these hadronic showers and also to distinguish them from electromagnetic ones. In addition, the comparison of these track segments in data and the simulation helps to discriminate among the different shower models used in the simulation. To extract the track segments in the showers recorded in the SDHCAL, a Hough Transform is used after being adapted to the presence of the dense core of the hadronic showers and the SDHCAL active medium structure.

HARDROC3, a 3rd generation ASIC with zero suppress for ILC Semi Digital Hadronic Calorimeter

HARDROC is the front end chip designed to read out the Resistive Plate Chambers foreseen for the Digital HAdronic CALorimeter (DHCAL) of the future International Linear Collider. The very fine granularity of the calorimeter implies thousands of electronics channels per cubic meter which is a new feature of “imaging” calorimetry. Moreover, for compactness, chips must be embedded inside the detector making crucial the reduction of the power consumption down to 12 μ W per channel. This is achieved using power-pulsing and online zero-suppression. Around 800 HARDROC3 were produced in 2015. The overall performance and production tests will be detailed.

Energy Reconstruction in a High Granularity Semi-Digital Hadronic Calorimeter for ILC Experiments

The Semi-Digital Hadronic CALorimeter (SDHCAL) is one of the two hadronic calorimeter options proposed by the International Large Detector (ILD) project for the future International Linear Collider (ILC) experiments. It is a sampling calorimeter with 48 active layers made of Glass Resistive Plate Chambers (GRPCs) and their embedded electronics. A fine lateral segmentation is obtained thanks to pickup pads of 1 cm2. This ensures the high granularity required for the application of the Particle Flow Algorithm (PFA) in order to improve the jet energy resolution in the ILC experiments. The performance of the SDHCAL technological prototype was tested successfully in several beam tests at CERN. The main point to be discussed here concerns the energy reconstruction in SDHCAL. Based on Monte Carlo simulation of the SDHCAL prototype using the GEANT4 package, we present different energy reconstruction methods to study the energy linearity and resolution of the detector response to single hadrons. In particular, we highlight a new technique based on the Artificial Neural Network giving promising results compared to analytic methods.

Performance of the SDHCAL technological prototype

The SDHCAL technological prototype is a 1 × 1 × 1.3 m3 high-granularity Semi-Digital Hadronic CALorimeter using Glass Resistive Plate Chambers as sensitive medium. It is one of the two HCAL options considered by the ILD Collaboration to be proposed for the detector of the future International Linear Collider project. The prototype is made of up to 50 GRPC detectors of 1 m2 size and 3 mm thickness each with an embedded semi-digital electronics readout that is autotriggering and power-pulsed. The GRPC readout is finely segmented into pads of 1 cm2. This proceeding describes the prototype, its operation and its performance in energy reconstruction. Aspects of the GRPC readout modelling and comparisons with simulations are also presented.

Resistive Plate Chamber digitization in a hadronic shower environment

The CALICE Semi-Digital Hadronic Calorimeter technological prototype is a sampling calorimeter using Glass Resistive Plate Chamber detectors with a three-threshold readout as the active medium. This technology is one of the two options proposed for the hadronic calorimeter of the International Large Detector for the International Linear Collider. The prototype was exposed to beams of muons, electrons and pions of different energies at the CERN Super Proton Synchrotron. To be able to study the performance of such a calorimeter in future experiments it is important to ensure reliable simulation of its response. This paper presents the SDHCAL prototype simulation performed with GEANT4 and the digitization procedure achieved with an algorithm called SimDigital. A detailed description of this algorithm is given and the methods to determinate its parameters using muon tracks and electromagnetic showers are explained. The comparison with hadronic shower data shows a good agreement up to 50 GeV. Discrepancies are observed at higher energies. The reasons for these differences are investigated.

First results of the CALICE SDHCAL technological prototype

The CALICE Semi-Digital Hadronic Calorimeter (SDHCAL) prototype, built in 2011, was exposed to beams of hadrons, electrons and muons in two short periods in 2012 on two different beam lines of the CERN SPS. The prototype with its 48 active layers, made of Glass Resistive Plate Chambers and their embedded readout electronics, was run in triggerless and power-pulsing mode. The performance of the SDHCAL during the test beam was found to be very satisfactory with an efficiency exceeding 90% for almost all of the 48 active layers. A linear response (within ± 5%) and a good energy resolution are obtained for a large range of hadronic energies (5–80 GeV) by applying appropriate calibration coefficients to the collected data for both the Digital (Binary) and the Semi-Digital (Multi-threshold) modes of the SDHCAL prototype. The Semi-Digital mode shows better performance at energies exceeding 30 GeV.

Energy reconstruction in a highly granularity semi-digital hadronic calorimeter

The Semi-Digital Hadronic CALorimeter(SDHCAL) using Glass Resistive Plate Chambers (GRPCs) is one of the calorimeters proposed for particle physics experiments at the future electron-positron collider. It is a high granularity calorimeter which is required for the application of the particle flow algorithm in order to improve the jet energy resolution as one of the goals of this experiments. We discuss the energy reconstruction, based on digital and semi-Digital methods, to study the effect on the improvement of the single particle energy resolution and the linearity of the detecor response. This study was performed with the GEANT4 simulation. Results on the energy resolution and linearity, for negative pions over an energy range from 1 to 100 GeV are presented and compared with different energy reconstruction methods including Artificial Neural Networks.

Construction and commissioning of a technological prototype of a high-granularity semi-digital hadronic calorimeter

A large prototype of 1.3 m3 was designed and built as a demonstrator of the semi-digital hadronic calorimeter (SDHCAL) concept proposed for the future ILC experiments. The prototype is a sampling hadronic calorimeter of 48 units. Each unit is built of an active layer made of 1 m2 Glass Resistive Plate Chamber (GRPC) detector placed inside a cassette whose walls are made of stainless steel. The cassette contains also the electronics used to read out the GRPC detector. The lateral granularity of the active layer is provided by the electronics pick-up pads of 1 cm2 each. The cassettes are inserted into a self-supporting mechanical structure built also of stainless steel plates which, with the cassettes walls, play the role of the absorber. The prototype was designed to be very compact and important efforts were made to minimize the number of services cables to optimize the efficiency of the Particle Flow Algorithm techniques to be used in the future ILC experiments. The different components of the SDHCAL prototype were studied individually and strict criteria were applied for the final selection of these components. Basic calibration procedures were performed after the prototype assembling. The prototype is the first of a series of new-generation detectors equipped with a power-pulsing mode intended to reduce the power consumption of this highly granular detector. A dedicated acquisition system was developed to deal with the output of more than 440000 electronics channels in both trigger and triggerless modes. After its completion in 2011, the prototype was commissioned using cosmic rays and particles beams at CERN.

Study of the performance of a semi-digital hadronic calorimeter using Monte Carlo techniques

The Particle Flow Algorithm is one of the main concepts that will be used to measure the energies of hadronic jets at a future International Linear Collider. This method requires a highly granular hadronic calorimeter to measure the energy of jets with a good precision. The Semi-Digital Hadronic Calorimeter using glass resistive plate chambers as sensitive medium is one of the hadronic calorimeters which is used in conjunction with the particle flow method. In this paper, the performance of Semi-Digital Hadronic Calorimeter using glass resistive plate chambers as active elements has been studied by using the GEANT4 simulations. Its main operational characteristics such as mean response and energy resolution have been examined.

High granularity Semi-Digital Hadronic Calorimeter using GRPCs

A Semi-Digital Hadronic Calorimeter using Glass Resistive Plate Chambers (GRPCs) is one of the calorimeters candidates proposed for particle physics experiments at the future electrons collider. It is a high granular calorimeter which is required for application of the particle flow algorithm in order to improve the jet energy resolution to achieve 30%/E as one of the goals of these experiments.

Construction of a technological semi-digital hadronic calorimeter using GRPC

A high-granularity semi-digital Hadronic calorimeter using GRPC as sensitive medium is one of the two HCAL options considered by the ILD collaboration to be proposed for the detector of the future International Linear Collider project. A prototype of 1m3 has been conceived within the CALICE collaboration in order to validate this option. The prototype intends to be as close as possible to the one proposed in the ILD Letter Of Intent. Few units made of 1m2 GRPC fully equipped with semi-digital readout electronics and new gas distribution design were produced and successfully tested. In 2010 we intend to produce 40 similar units to be inserted in a self-supporting mechanical structure. The prototype will then be exposed to TestBeams at CERN for final validation.