Silicon-tungsten Electromagnetic Calorimeter Research Articles

The CALICE SiW ECAL Technological Prototype—Status and Outlook

The next generation of collider detectors will make full use of Particle Flow Algorithms, requiring high-precision tracking and full imaging calorimeters. The latter, thanks to granularity improvements by two to three orders of magnitude compared to existing devices, have been developed during the past 15 years by the CALICE collaboration and are now reaching maturity. This contribution will focus on the commissioning of a 15-layer prototype of a highly granular silicon–tungsten electromagnetic calorimeter that comprises 15,360 readout cells. The prototype was exposed in November 2021 and March 2022 to beam tests at DESY and in June 2022 to a beam test at the SPS at CERN. The test at CERN has been carried out in combination with the CALICE Analogue Hadron Calorimeter. The contribution will give a general overview of the prototype and will highlight technical developments necessary for its construction.

Beam test performance of a highly granular silicon tungsten calorimeter technical prototype for the ILD

A highly granular silicon-tungsten electromagnetic calorimeter (SiW-ECAL) is the reference design of the ECAL for International Large Detector concept, one of the two detector concepts for the future International Linear Collider. Prototypes for this type of detector are developed within the CALICE Collaboration. The technological prototype addresses technical challenges such as integrated front-end electronics or compact layer and readout design. A stack of 7 layers was compiled and tested at DESY test beam facilities in 2017. We present preliminary results on the properties of the electromagnetic showers. An outline on the next steps is given. Finally, we illustrate the first steps of the digitization concept on simulations of the prototype.

Development and characterization of a large area silicon pad array for an electromagnetic calorimeter

We present the research and development work of the first version of a 6×6 array of silicon pad detectors, carried out in India, for the proposed forward calorimeter (FOCAL) as part of the ALICE collaboration upgrade program at CERN. The primary motivation is to develop a large area silicon pad array realizing the challenging requirements of high-energy physics experiments such as low leakage current, high breakdown voltage and evaluate its performance as an active layer in the prototype silicon tungsten (Si-W) electromagnetic (EM) calorimeter. Towards these goals, a 36-pad silicon sensor with an individual pad size of ∼1 cm2 is designed on a 4-inch high resistivity N-type wafer and fabricated at Bharat Electronics Limited, Bangalore. The sensors have been used to assemble the prototype Si-W calorimeters and were successfully tested with high-energy particle beams. The design and development of the large area silicon sensor and its characterization using radioactive sources in the laboratory and high-energy particle beams are reported in this paper.

CALICE SiW ECAL—development and test of the chip-on-board PCB solution

The highly granular silicon-tungsten electromagnetic calorimeter (SiW ECAL) is the reference design of the ECAL for the International Large Detector (ILD) concept, one of the two detector concepts proposed for the future International Linear Collider (ILC). Prototypes for this type of detector are developed within the CALICE Collaboration. This contribution reports on the development of an ultra-thin PCB called Chip-on-Board (COB) that is equipped with wirebonded ASICs and pixelated silicon wafers. This set will form the basic unit of detection of the SiW ECAL. It will favour the design of an ultra compact calorimeter since these boards feature a thickness of 1.2 mm to be compared with the 3 mm of the default solution variant using ASICs in BGA packaging. We report also on the first results obtained with the COB boards on a beam test at DESY.

Study of position sensitive silicon detector (PSD) for SiW-ECAL at ILC

For the past few years we have been developing position sensitive silicon detectors (PSDs) which have an electrode at each of four corners so that incident position of a charged particle can be obtained with signal from the electrodes. It is expected that the position resolution of the silicon-tungsten electromagnetic calorimeter (SiW-ECAL) of the International Large Detector (ILD) will be improved by introducing PSDs to detection layers. In the previous production we found that the charge separation is not optimal due to the readout impedance. To solve the issue, we produced new PSDs with higher surface resistance with an additional resistive layer on the surface. We also implemented several techniques to decrease position distortion and increase signal-to-noise ratio which are essential for optimal position resolution. We present first measurements of the performance of one new PSD using a strontium 90 source, and using the Skiroc2-CMS ASIC.

CALICE SiW ECAL—Development and performance of a highly compact digital readout system

A highly granular silicon-tungsten electromagnetic calorimeter (SiW-ECAL) is the reference design of the ECAL of the International Large Detector (ILD) concept, one of the two detector concepts for the detector(s) at the future International Linear Collider. Prototypes for this type of detector are developed within the CALICE Collaboration. During the last year a highly compact digital readout system has been built. The system has been used for the first time in a beam test in Summer 2019 at DESY. This article summarises the main features of the system and report on its performance during the beam test.

Beam test performance of the highly granular SiW-ECAL technological prototype for the ILC

The technological prototype of the CALICE highly granular silicon-tungsten electromagnetic calorimeter (SiW-ECAL) was tested in a beam at DESY in 2017. The setup comprised seven layers of silicon sensors. Each layer comprised four sensors, with each sensor containing an array of 256 $5.5\times5.5$ mm$^2$ silicon PIN diodes. The four sensors covered a total area of $18\times18$ cm$^2$, and comprised a total of 1024 channels. The readout was split into a trigger line and a charge signal line. Key performance results for signal over noise for the two output lines are presented, together with a study of the uniformity of the detector response. Measurements of the response to electrons for the tungsten loaded version of the detector are also presented.

ILD silicon tungsten electromagnetic calorimeter first full scale electronic prototype

The “long slab” is a new prototype for the SiW-Ecal, a silicon tungsten electromagnetic calorimeter for the International Large Detector (ILD) at the future International Linear Collider (ILC). The new prototype has been evaluated with cosmics, radioactive sources and with 3 GeV electrons in beam tests at the DESY facility, Hamburg. A channel-wise calibration has been achieved, at different angles of incidence of the beam on the sensors. Using data collected at non-normal incidence, the signal of particles traversing adjacent pixels were used to estimate the absolute value of the trigger threshold in units of mips. This new prototype provides us many hints on how to improve the design of the front-end electronics. It is also a convenient tool to estimate the critical characteristics of ILD SiW-Ecal (like power consumption, cooling, readout time, etc.) and to optimise the future design of the detector.

Recent results of the technological prototypes of the CALICE highly granular calorimeters

The CALICE Collaboration is conducting R&D for highly granular calorimeters with an emphasis on detectors for Linear Colliders. This contribution briefly summarises recent tests of large scale technological prototypes of a silicon tungsten electromagnetic calorimeter and hadron calorimeters featuring either a gaseous medium or scintillator with a SiPM readout as active material.

Characterisation of different stages of hadronic showers using the CALICE Si-W ECAL physics prototype

A detailed investigation of hadronic interactions is performed using $\pi^-$-mesons with energies in the range 2--10 GeV incident on a high granularity silicon-tungsten electromagnetic calorimeter. The data were recorded at FNAL in 2008. The region in which the $\pi^-$-mesons interact with the detector material and the produced secondary particles are characterised using a novel track-finding algorithm that reconstructs tracks within hadronic showers in a calorimeter in the absence of a magnetic field. The principle of carrying out detector monitoring and calibration using secondary tracks is also demonstrated.

Energy reconstruction of hadrons in highly granular combined ECAL and HCAL systems

This paper discusses the hadronic energy reconstruction of two combined electromagnetic and hadronic calorimeter systems using physics prototypes of the CALICE collaboration: the silicon-tungsten electromagnetic calorimeter (Si-W ECAL) and the scintillator-SiPM based analog hadron calorimeter (AHCAL); and the scintillator-tungsten electromagnetic calorimeter (ScECAL) and the AHCAL. These systems were operated in hadron beams at CERN and FNAL, permitting the study of the performance in combined ECAL and HCAL systems. Two techniques for the energy reconstruction are used, a standard reconstruction based on calibrated sub-detector energy sums, and one based on a software compensation algorithm making use of the local energy density information provided by the high granularity of the detectors. The software compensation-based algorithm improves the hadronic energy resolution by up to 30% compared to the standard reconstruction. The combined system data show comparable energy resolutions to the one achieved for data with showers starting only in the AHCAL and therefore demonstrate the success of the inter-calibration of the different sub-systems, despite of their different geometries and different readout technologies.

Latest R&D news and beam test performance of the highly granular SiW-ECAL technological prototype for the ILC

High precision physics at future colliders as the International Linear Collider (ILC) require unprecedented high precision in the determination of the energy of final state particles. The needed precision will be achieved thanks to the Particle Flow algorithms (PF) which require highly granular and hermetic calorimeters systems. The physical proof of concept of the PF was performed in the previous campaign of beam tests of physic prototypes within the CALICE collaboration. One of these prototypes was the physics prototype of the Silicon-Tungsten Electromagnetic Calorimeter (SiW-ECAL) for the ILC. In this document we present the latest news on R&D of the next generation prototype, the technological prototype with fully embedded very front-end (VFE) electronics, of the SiW-ECAL. Special emphasis is given to the presentation and discussion of the first results from the beam test done at DESY in June 2017. The physics program for such beam test consisted in the calibration and commissioning of the current set of available SiW ECAL modules; the test of performance of individual slabs under 1T magnetic fields; and the study of electromagnetic showers events.

Towards a Technological Prototype for a High-granularity Electromagnetic Calorimeter for Future Lepton Colliders

The CALICE collaboration is preparing large scale prototypes for highly granular calorimeters for detectors to be operated at a future lepton collider. Currently a prototype of a silicon-tungsten electromagnetic calorimeter SiW-ECAL will be assembled which in terms of dimensions and layout meets already most of the requirements given by the lepton collider physics programme and hence the detector design. In particular the front end electronics will be embedded into the layer structure of the calorimeter and have to fit within alveolar layers with less than 1 cm in height. In this paper the design of the prototype and the steps towards the realisation are presented. The presented technology plays also a key role in the upgrades of the LHC Experiments CMS and ATLAS.

Hadrons in the CALICE silicon-tungsten electromagnetic calorimeter

A detailed study of hadronic interactions is presented using data recorded with the highly granular CALICE silicon-tungsten electromagnetic calorimeter. The predictions of several Monte Carlo Geant4 models are compared with experimental data, taken at FNAL in 2008. The contribution recaps results published in 2015 and a set of new results available since the beginning of 2016. The published results present a detailed analysis of hadronic showers in terms of radial and longitudinal hit and energy distributions. For the most recent analysis a simple track-finding algorithm was developed to study tracks left by secondary particles, emerging from hadronic interactions in the highly granular electromagnetic calorimeter prototype. Present Monte Carlo simulations provide a good description of the experimental data in terms of new observables, available through the detailed analysis of secondary particles; the Monte Carlo predictions are within 20% of the data, and for many observables much closer.

SiW ECAL for future e+e− collider

Calorimeters with silicon detectors have many unique features and are proposed for several world-leading experiments. We discuss the tests of the first three 18×18 cm2 layers segmented into 1024 pixels of the technological prototype of the silicon-tungsten electromagnetic calorimeter for a future e+e− collider. The tests have beem performed in November 2015 at CERN SPS beam line.

H, He, Li and Be Isotopes in the PAMELA-Experiment

On the 15th of June 2006, the PAMELA satellite-borne experiment was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. The apparatus comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anti-coincidence system, a shower tail counter scintillator and a neutron detector. The scientific objectives addressed by the mission are the measurement of the antiprotons and positrons spectra in cosmic rays, the hunt for antinuclei as well as the determination of light nuclei fluxes from hydrogen to oxygen in a wide energy range and with very high statistics. In this paper the identification capability for light nuclei isotopes using two different detector systems (Time-of-Flight and multiple dE/dx measurements in the calorimeter) and preliminary results of the isotopic ratios will be presented.

Technological prototype of a silicon-tungsten imaging electromagnetic calorimeter

Highly granular calorimeters and particle flow algorithms are essential tools for achieving an excellent jet energy resolution. This is a key asset for precision physics at future high energy particle colliders aiming at precise physics measurements. The PFA concept is best supported by a silicon tungsten electromagnetic calorimeter. The R&D as carried out by the CALICE collaboration has shown the feasibility of a fine-grained pixelization while assuring high operation stability. Our concept has been selected to compete for the upgrade of the CMS ECAL. The latest version of our detector concept, featuring 1024 channels on 4 dm2 board will be presented including technological choices for an application on an ILC. First thoughts for the CMS ECAL upgrade will be discussed.

Testing hadronic interaction models using a highly granular silicon–tungsten calorimeter

A detailed study of hadronic interactions is presented using data recorded with the highly granular CALICE silicon–tungsten electromagnetic calorimeter. Approximately 350,000 selected π− events at energies between 2 and 10GeV have been studied. The predictions of several physics models available within the GEANT4 simulation tool kit are compared to this data. A reasonable overall description of the data is observed; the Monte Carlo predictions are within 20% of the data, and for many observables much closer. The largest quantitative discrepancies are found in the longitudinal and transverse distributions of reconstructed energy.

R&D for a highly granular silicon tungsten electromagnetic calorimeter

This article reports on first experience with the technological prototype of a highly- granular silicon-tungsten electromagnetic calorimeter as envisaged for the detectors at a future lepton collider. In the focus of the analysis is the performance of a highly integrated Application Specific Integrated Circuit designed to meet the requirements in terms of dynamic range, compactness and power consumption. The beam test results show that the circuit will allow a future detector with a signal over noise ratio of at least 10:1. To minimise the power dissipation the ASIC will be operated in a power pulsed mode. So far no conceptual problem was revealed but the studies show the way for further work. The prototype is read out by a DAQ system conceived to meet the needs of a trigger less system with a huge number of readout cells.

Construction and testing of a large scale prototype of a silicon tungsten electromagnetic calorimeter for a future lepton collider

The CALICE collaboration is preparing large scale prototypes of highly granular calorimeters for detectors to be operated at a future linear electron positron collider. After several beam campaigns at DESY, CERN and FNAL, the CALICE collaboration has demonstrated the principle of highly granular electromagnetic calorimeters with a first prototype called physics prototype. The next prototype, called technological prototype, addresses the engineering challenges which come along with the realisation of highly granular calorimeters. This prototype will comprise 30 layers where each layer is composed of four 9×9cm2 silicon wafers. The front end electronics is integrated into the detector layers. The size of each pixel is 5×5mm2. This prototype enters its construction phase.We present results of the first layers of the technological prototype obtained during beam test campaigns in spring and summer 2012. According to these results the signal over noise ratio of the detector exceeds the R&D goal of 10:1.