Digital Hadron Calorimeter Research Articles

Calorimetry with Extremely Fine Spatial Segmentation

Particle Flow Algorithms (PFAs) attempt to measure each particle in a hadronic jet individually, using the detector subsystem that provides the best energy/momentum resolution. Calorimeters that can exploit the power of PFAs emphasize spatial granularity over single particle energy resolution. In this context, the CALICE Collaboration developed the Digital Hadron Calorimeter (DHCAL). The DHCAL uses Resistive Plate Chambers (RPCs) as active media and is read out with 1 × 1 cm2 pads and digital (1-bit) resolution. In order to obtain a unique dataset of electromagnetic and hadronic interactions with unprecedented spatial resolution, the DHCAL went through a broad test beam program. In addition to conventional calorimetry, the DHCAL offers detailed measurements of event shapes, rigorous tests of simulation models and various analytical tools to improve calorimetric performance. Here we report on the results from the analysis of DHCAL data and comparisons with the Monte Carlo simulations.

Development of Novel Designs of Resistive Plate Chambers

Resistive Plate Chambers (RPCs) are a key active media of the muon systems of current and future collider experiments as well as the CALICE (semi-)digital hadron calorimeter. The outstanding issues with RPCs can be listed as the loss of efficiency for the detection of particles when subjected to high particle fluxes and the limitations associated with the common RPC gases. We developed novel RPC designs with: low resistivity glass plates; a single resistive plate; and a single resistive plate and a special anode plate coated with high secondary electron emission yield material. The cosmic and beam tests confirmed the viability of these new approaches for calorimetric applications. The chambers also have improved single-particle response, such as a pad multiplicity close to unity. Here, we report on the construction of various different glass RPC designs and their performance measurements in laboratory tests and with particle beams. We also discuss future test plans, which include the long-term performance tests of the newly developed RPCs, investigation of minimal gas flow chambers, and feasibility study for the large-size chambers.

Development of compact micro-pattern gaseous detectors for the CEPC digital hadron calorimeter

An imaging hadron calorimeter with digital readout (DHCAL) using the micro-pattern gaseous detector (MPGD) technology is one of the hadron calorimeter options for the Circular Electron Positron Collider (CEPC). The sensitive detector of the CEPC DHCAL is required to be compact and highly efficient for MIPs with low hit multiplicity. A double-GEM detector and a resistive WELL (RWELL) detector based on the THGEM technique have been investigated as options for the DHCAL sensitive detector. A 030 cm × 3 cm double-GEM prototype with “3 mm-1 mm-1 mm” structure was built with the self-stretching technique to study the performance of the double-GEM detector for application to the CEPC DHCAL. The double-GEM prototype was read out with the MICROROC chip and tested with cosmic-rays. The results of the test show a detection efficiency higher than 95% and a hit multiplicity of 1.2. Compared with the GEM detector, the RWELL detector is advantageous in minimizing the dead area due to its simple assembly without stretching. In addition, it has a more compact structure than the double-GEM detector thanks to its single-stage gas amplification without any induction gap. A 25 cm × 25 cm RWELL prototype with a resistivie DLC electrode was developed by using the thermal bonding technique. And a fast grounding circuit was designed on its anode PCB to enhance the rate capability of the detector. Preliminary results from tests of the RWELL prototype with X-rays show that the detector could operate at a gain of 0∼800 with a 0∼2% uniformity, maintain such a gain when irradiated with 8 keV X-rays at a rate of 0∼30 kHz/cm2. Based on these results, the RWELL detector promises to be a good candidate as the sensitive detector of the CEPC DHCAL, which merits further studies.

Analysis of testbeam data of the highly granular RPC-steel CALICE digital hadron calorimeter and validation of Geant4 Monte Carlo models

We present a study of the response of the highly granular Digital Hadronic Calorimeter with steel absorbers, the Fe-DHCAL, to positrons, muons, and pions with momenta ranging from 2 to 60 GeV/c. Developed in the context of the CALICE collaboration, this hadron calorimeter utilises Resistive Plate Chambers as active media, interspersed with steel absorber plates. With a transverse granularity of $1\,\times\,1\,$cm$^{2}$ and a longitudinal segmentation of 38 layers, the calorimeter counted 350,208 readout channels, each read out with single-bit resolution (digital readout). The data were recorded in the Fermilab test beam in 2010-11. The analysis includes measurements of the calorimeter response and the energy resolution to positrons and muons, as well as detailed studies of various shower shape quantities. The results are compared to simulations based on Geant4, which utilise different electromagnetic and hadronic physics lists.

Digital Hadron Calorimetry

The Particle Flow Algorithms attempt to measure each particle in a hadronic jet individually, using the detector providing the best energy/momentum resolution. Therefore, the spatial segmentation of the calorimeter plays a crucial role. In this context, the CALICE Collaboration developed the Digital Hadron Calorimeter. The Digital Hadron Calorimeter uses Resistive Plate Chambers as active media and has a 1-bit resolution (digital) readout of 1 × 1 cm2 pads. The calorimeter was tested with steel and tungsten absorber structures, as well as with no absorber structure, at the Fermilab and CERN test beam facilities over several years. In addition to conventional calorimetric measurements, the Digital Hadron Calorimeter offers detailed measurements of event shapes, rigorous tests of simulation models and various tools for improved performance due to its very high spatial granularity. Here we report on the results from the analysis of pion and positron events. Results of comparisons with the Monte Carlo simulations are also discussed. The analysis demonstrates the unique utilization of detailed event topologies.

Development of a double-GEM detector using the self-stretching technique for digital hadron calorimetry

A digital hadron calorimeter (DHCAL) has been proposed for precision jet-energy measurement by means of the particle flow algorithm for the experiment at the Circular Electron Positron Collider (CEPC). Among various candidate detector technologies for the sensitive layers of the CEPC-DHCAL, the gaseous electron multiplier (GEM) is an attractive option. A prerequisite for application of GEM to DHCAL is its scalability to very large size. The self-stretching technique is a novel method for assembling large-size GEM detectors, making it a promising GEM assembly technique in DHCAL application. As part of the R&D program for the CEPC-DHCAL, a double-GEM detector with an active area of 30×30 cm2 has been constructed using the self-stretching technique. The double-GEM structure was adopted to better meet the requirement of compactness of DHCAL sensitive layers. The design and assembly of the double-GEM detector is described. Results from various tests of the detector with X-rays are also presented. Good performance of the double-GEM detector has been demonstrated for the DHCAL application.

DHCAL with minimal absorber: measurements with positrons

In special tests, the active layers of the CALICE Digital Hadron Calorimeter prototype, the DHCAL, were exposed to low energy particle beams, without being interleaved by absorber plates. The thickness of each layer corresponded approximately to 0.29 radiation lengths or 0.034 nuclear interaction lengths, defined mostly by the copper and steel skins of the detector cassettes. This paper reports on measurements performed with this device in the Fermilab test beam with positrons in the energy range of 1 to 10 GeV. The measurements are compared to simulations based on GEANT4 and a standalone program to emulate the detailed response of the active elements.

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.

Design, construction and commissioning of the Digital Hadron Calorimeter—DHCAL

A novel hadron calorimeter is being developed for future lepton colliding beam detectors. The calorimeter is optimized for the application of Particle Flow Algorithms (PFAs) to the measurement of hadronic jets and features a very finely segmented readout with 1 × 1 cm2 cells. The active media of the calorimeter are Resistive Plate Chambers (RPCs) with a digital, i.e. one-bit, readout. To first order the energy of incident particles in this calorimeter is reconstructed as being proportional to the number of pads with a signal over a given threshold. A large-scale prototype calorimeter with approximately 500,000 readout channels has been built and underwent extensive testing in the Fermilab and CERN test beams. This paper reports on the design, construction, and commissioning of this prototype calorimeter.

DHCAL with minimal absorber: measurements with positrons

In special tests, the active layers of the CALICE Digital Hadron Calorimeter prototype, the DHCAL, were exposed to low energy particle beams, without being interleaved by absorber plates. The thickness of each layer corresponded approximately to 0.29 radiation lengths or 0.034 nuclear interaction lengths, defined mostly by the copper and steel skins of the detector cassettes. This paper reports on measurements performed with this device in the Fermilab test beam with positrons in the energy range of 1 to 10 GeV. The measurements are compared to simulations based on GEANT4 and a standalone program to emulate the detailed response of the active elements.

P/π+ response of single layer THGEM detector in Ar+3% iC4H10**Supported by National Natural Science Foundation of China (11265003, U1431109, 11205240) and State Key Laboratory of Particle Detection and Electronics

In this work, we study the response of a single layer Thick Gaseous Electron Multiplier (THGEM) detector to p/π+ at the E3 line of the Beijing Test Beam Facility. The THGEM detector drift gap used in this study is 4 mm, and the gain of the detector operated in Ar+3% iC4H10 is about 2000. p/π+ particles at momenta between 500 MeV/c and 1000 MeV/c are distinguished by a Time Of Flight system. Our results show that at the measured momenta, detection efficiencies for p are from 93% to 99%, and for π+ in the range of 82%–88%. Meanwhile, simple Geant4 simulations also have been done, and are consistent with the amplitude spectra of the beam test results. We preliminarily study the feasibility of the THGEM detector as a sampling element for a Digital Hadronic Calorimeter (DHCAL), which may provide support for the possible application of a THGEM detector in the Circular Electron Positron Collider (CEPC) HCAL.

The CALICE digital hadron calorimeter: calibration and response to pions and positrons

In order to measure the jet products of the hadronic decays of electroweak bosons in a future lepton collider with 3-4% resolution, a novel approach named Particle Flow Algorithms is proposed. The Particle Flow Algorithms attempt to measure each particle in a hadronic jet individually, using the detector providing the best energy/momentum resolution. The role of the hadronic calorimeters is to measure the neutral component of the hadronic jets. In this context, the CALICE Collaboration developed the Digital Hadron Calorimeter, which uses Resistive Plate Chambers as active media. The 1-bit resolution (digital) readout of 1 × 1 cm2 pads achieves a world record in the number of readout channels already at the prototyping stage. Here we report on the results from the analysis of pion events of momenta between 2 to 60 GeV/c collected in the Fermilab test beam with an emphasis on the intricate calibration procedures.

Resistive Plate Chambers for imaging calorimetry — The DHCAL

The DHCAL — the Digital Hadron Calorimeter — is a prototype calorimeter based on Resistive Plate Chambers (RPCs). The design emphasizes the imaging capabilities of the detector in an effort to optimize the calorimeter for the application of Particle Flow Algorithms (PFAs) to the reconstruction of hadronic jet energies in a colliding beam environment. The readout of the chambers is segmented into 1 × 1 cm2 pads, each read out with a 1-bit (single threshold) resolution. The prototype with approximately 500,000 readout channels underwent extensive testing in both the Fermilab and CERN test beams. This talk presents preliminary findings from the analysis of data collected at the test beams.

Developments of oil-free Bakelite resistive plate chambers for particle physics experiments

In this paper, we sumarized a Bakelite Resistive Plate Chamber (RPC) with non-oil surface treatment. This type of RPC has been installed and run smoothly in BESIII Muon identification system and Daya Bay cosmic Muon veto system. Based on its good performances, it has been futher studied as the sensitive detector of a digital hadron calorimeter for measuring the energies of particles in a hadron jet and as a thermal neutron detector. In addition, since the bulk resistivity of Bakelite plates can be controlled, futher developments with low bulk resistivity are being undertaken to guarantee high rate capability in experiments.

English

By using the tungsten as passive element and the Glass Resistive Plate Chambers (GRPCs) as active element, the gaseous hadronic calorimeter is studied as a possible detector for the future International Linear Collider (ILC). The results of the numerical study, using the GEANT4 simulation package, of the performance of this calorimeter when it is exposed to a negative pion beam in an energy range from 5 GeV to 100 GeV are presented in this paper. Operating characteristics of this prototype, such as signal linearity, energy resolution and reconstructed energy have been simulated and examined. Moreover, a comparison between the Digital Hadron Calorimeter (DHCAL) and the Analog Hadron Calorimeter (AHCAL) is made.   Key words: Calorimetry, resistive plate chambers, international linear collider (ILC), GEANT4.

Development of a Gas Electron Multiplier-based Digital Hadron Calorimeter

We describe the development of large-area (1m×1m), very thin, and high sensitivity gas detector based on gas electron multiplier (GEM) technology as a sensitive medium for sampling calorimeters for a use in future collider experiments.

Construction of the DHCAL

Particle Flow Algorithms (PFAs) have been proposed as a method of improving the jet energy resolution of future colliding beam detectors. PFAs require calorimeters with high granularity to enable three-dimensional imaging of events. The Calorimeter for the Linear Collider Collaboration (CALICE) is developing and testing prototypes of such highly segmented calorimeters. In this context, a large prototype of a Digital Hadron Calorimeter (DHCAL) was developed and constructed by a group led by Argonne National Laboratory. The DHCAL consists of 52 layers, instrumented with Resistive Plate Chambers (RPCs) and interleaved with steel absorber plates. The RPCs are read out by 1 x 1 cm2 pads with a 1-bit resolution (digital readout). The DHCAL prototype has approximately 480,000 readout channels. This talk reports on the design, construction and commissioning of the DHCAL. The DHCAL was installed at the Fermilab Test Beam Facility in fall 2010 and data was collected through the summer 2011.

DHCAL Response to Positrons and Pions

Abstract The large Digital Hadron Calorimeter (DHCAL) prototype was constructed and has been tested in several test beam campaigns in the FTBF test beam in Fermilab since October 2010. The active medium is Resistive Plate Chambers (RPCs) and the readout is segmented into 1 x 1 cm 2 pads, each with a single bit resolution, resulting in about 0.5 million readout channels in less than 2 m 3 of detector volume. In this paper we report on results from a first look at the DHCAL data to assess the calorimetric properties of the DHCAL. We present preliminary results from the analysis of both positron and pion events of momenta between 2 and 60 GeV/c. These results are considered to be a first validation of the viability of the DHCAL concept.

Analysis of Muon Events in the DHCAL

The Digital Hadron Calorimeter (DHCAL) is a large prototype of an imaging calorimeter using Resistive Plate Chambers (RPCs) as active media. The readout is segmented into 1×1 cm2 pads, each with a single bit resolution, hence the denomination of digital. The total channel count is close to 500,000. The DHCAL construction and assembly was completed in fall 2010, followed by a series of test beam campaigns in the FTBF test beam at Fermilab. In this paper we report on the analysis of events collected with the broadband muon beam. These events are utilized to geometrically align the layers horizontally and vertically, to establish the response as function of position on a single readout pad, and to measure the performance characteristics of the RPCs, i.e. the efficiency and average pad multiplicity. The latter were measured in both ‘clean’ regions of the detector, i.e. away from structures such as the rims of the chambers, and as function of position on the entire vertical plane. In addition, the paper reviews the preliminary measurements of the noise rate in the detector.

MICROROC: MICRO-mesh gaseous structure Read-Out Chip

MICRO MEsh GAseous Structure (MICROMEGAS) and Gas Electron Multipliers (GEM) detectors are two candidates for the active medium of a Digital Hadronic CALorimeter (DHCAL) as part of a high energy physics experiment at a future linear collider (ILC/CLIC). Physics requirements lead to a highly granular hadronic calorimeter with up to thirty million channels with probably only hit information (digital readout calorimeter).To validate the concept of digital hadronic calorimetry with such small cell size, the construction and test of a cubic meter technological prototype, made of 40 planes of one square meter each, is necessary. This technological prototype would contain about 400 000 electronic channels, thus requiring the development of front-end ASIC. Based on the experience gained with previous ASIC that were mounted on detectors and tested in particle beams, a new ASIC called MICROROC has been developped.This paper summarizes the caracterisation campaign that was conducted on this new chip as well as its integration into a large area Micromegas chamber of one square meter.