Test Beam Data Research Articles

Test Beam Results from sPHENIX prototype Time Projection Chamber

The sequential melting of Upsilon states gives us information about the Debye Screening length of Quark Gluon Plasma (QGP). To observe this sequential melting at RHIC energies of 200GeV, a Time Projection Chamber, as part of the sPHENIX detector assembly, with ability to resolve the Upsilon states is proposed. This paper details the construction of the prototype TPC, the method of analysis of test beam data and its results.

A fast and parametric digitization for triple-GEM detectors

Triple-GEM detectors are a well known technology in high energy physics. In order to have a complete understanding of their behavior, in parallel with on beam testing, a Monte Carlo code has to be developed to simulate their response to the passage of particles. The software must take into account all the physical processes involved from the primary ionization up to the signal formation, e.g. the avalanche multiplication and the effect of the diffusion on the electrons. In the case of gas detectors, existing software such as Garfield already perform a very detailed simulation but are CPU time consuming. A description of a reliable but faster simulation is presented here: it uses a parametric description of the variables of interest obtained by suitable preliminary Garfield simulations and tuned to the test beam data. It can reproduce the real values of the charge measured by the strip, needed to reconstruct the position with the Charge Centroid method. In addition, particular attention was put to the simulation of the timing information, which permits to apply also the micro-Time Projection Chamber position reconstruction, for the first time on a triple-GEM. A comparison between simulation and experimental values of some sentinel variables in different conditions of magnetic field, high voltage settings and incident angle will be shown.

A numerical investigation on the track distortion at the Micromegas based LPTPC endplate

The R&D activities for the Linear Collider TPC (LCTPC) are currently focused on the adoption of the Micro-Pattern Gaseous Detectors (MPGDs). Different MPGD modules which are commissioned on the endplate of a Large Prototype TPC (LPTPC) at DESY, were tested with a 5 GeV electron beam, under a 1 T magnetic field. During the tests, reduced signal sensitivity as well as distortion in the reconstructed track, were observed at the boundary of these modules.We have numerically investigated the origin of the track distortions observed close to the edges of the Micromegas modules. The study clearly shows that the electric field non-uniformity near the inter-modular gaps is responsible for such track distortion. We have been able to simulate the observed patterns and magnitudes of distortion successfully. The obtained agreements with 2015 beam test data encourage us to continue with the study and, to propose module design modifications that can alleviate the problem of electrostatic field distortion at the module boundaries.

First calorimetric energy reconstruction of beam events with ARAPUCA light detector in protoDUNE-SP

ProtoDUNE Single Phase at CERN is the large-scale prototype for the far detector of the future DUNE experiment. ProtoDUNE is in stable operation since Oct. 2018 at the CERN Neutrino Platform. Test beam data in the energy range of sub-GeV to a few GeV were collected in fall 2018 providing a set of key measurements. Particles (electrons, protons, pions, muons and kaons) are identified combining information from a set of beam-line detectors (Time of Flight, Cherenkov) and TPC reconstruction. Three different technologies are implemented in the protoDUNE photon detector system (PDS). Results from the response of ARAPUCA, one of the PDS components, are presented providing first calorimetric energy measurements of beam events from liquid argon scintillation light signals.

A way forward for industry to determine valid cyclic-fatigue relationships for polymer-matrix fibre composites

In the present paper a novel methodology is proposed for predicting an ‘upper-bound’ (i.e. ‘worst case’) fatigue crack growth (FCG) rate curve from laboratory double-cantilever beam (DCB) test data which is representative of a composite laminate exhibiting no, or only very little, retardation (i.e. slowing) of the FCG rate under fatigue loading, as is the case with most real-life applications. The proposed methodology also takes into account the inherent scatter of such fatigue tests. To achieve this we have employed a variant of the Hartman-Schijve equation. The resulting conservative ‘upper-bound’ FCG rate curve represents a unique and valid ‘upper-bound’ fatigue relationship which may be used in industrial applications for (a) material development, characterisation and comparative studies and (b) design and lifing studies.

Hadronic shower properties in highly granular calorimeters with different absorbers

The CALICE collaboration develops and tests highly granular calorimeter prototypes for future collider experiments. The scintillator-SiPM-based prototypes of hadron calorimeters with steel and tungsten absorbers were exposed to test beams from the CERN SPS in 2007-2011. The paper presents a comparison of hadronic shower properties observed in the test beam data. The application of software compensation technique is discussed for the energy reconstruction in calorimeters with different level of compensation. It was observed from the experimental data that the achieved improvement of relative energy resolution is about 20% for the noncompensating calorimeter, while it is less than 5% for the compensating one.

Study of Very Forward Neutrons with the CMS Zero Degree Calorimeter

Forward neutrons are studied in proton-lead collisions at the CMS experiment at the CERN LHC. They provide information on the centrality and event plane of collisions and provide an opportunity to study nuclear breakup. At the CMS experiment they are detected by the Zero Degree Calorimeters (ZDCs) in the | η | > 8.5 pseudorapidity range. The ZDCs are quartz fiber Cherenkov calorimeters using tungsten as absorber. Test beam data and events with a single spectator neutron are used for the calibration of these detectors. A Fourier-based method is used correct for the effect of multiple pPb collisions. The corrected ZDC energy distribution is used to calculate centrality percentiles and unfold the neutron multiplicity distribution.

In situ radiation damage studies of optoelectronics in the ATLAS SemiConductor Tracker

This paper presents results on in situ measurements of radiation damage for the on-detector optoelectronics for the ATLAS SemiConductor Tracker. The results come from proton-proton collisions in LHC during operation in 2016, 2017 and 2018. The results for both p - i - n diodes and VCSELs are given and compared to expectations from beam tests of devices from the same wafer, before the start of LHC operation. The VCSELs show evidence for some radiation damage as expected from earlier studies. The magnitude of the damage is compared with simple extrapolations from test beam data. The p - i - n diodes do show significant radiation damage as expected from test beam studies.

Performance of the Muon g−2 calorimeter and readout systems measured with test beam data

A single calorimeter station for the Muon $g-2$ experiment at Fermilab includes the following subsystems: a 54-element array of PbF$_{2}$ Cherenkov crystals read out by large-area SiPMs, bias and slow-control electronics, a suite of 800 MSPS waveform digitizers, a clock and control distribution network, a gain calibration and monitoring system, and a GPU-based frontend read out through a MIDAS data acquisition environment. The entire system performance was evaluated using 2.5 - 5 GeV electrons at the End Station Test Beam at SLAC. This paper includes a description of the individual subsystems and the results of measurements of the energy response and resolution, energy-scale stability, timing resolution, and spatial uniformity. All measured performances meet or exceed the $g-2$ experimental requirements. Based on the success of the tests, the complete production of the required 24 calorimeter stations has been made and installation into the main experiment is complete. Furthermore, the calorimeter response measurements determined here informed the design of the reconstruction algorithms that are now employed in the running $g-2$ experiment.

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.

Performance of thin planar n-on-p silicon pixels after HL-LHC radiation fluences

The tracking detector of ATLAS, one of the experiments at the Large Hadron Collider (LHC), will be upgraded in 2024–2026 to cope with the challenging environment conditions of the High Luminosity LHC (HL-LHC). The LPNHE, in collaboration with FBK and INFN, has produced 130μm thick n−on−p silicon pixel sensors which can withstand the expected large particle fluences at HL-LHC, while delivering data at high rate with excellent hit efficiency. Such sensors were tested in beam before and after irradiation both at CERN-SPS and at DESY, and their performance are presented in this paper. Beam test data indicate that these detectors are suited for all the layers where planar sensors are foreseen in the future ATLAS tracker: hit-efficiency is greater than 97% for fluences of Φ≲7×1015neq∕cm2 and module power consumption is within the specified limits. Moreover, at a fluence of Φ=1.3×1016neq∕cm2, hit-efficiency is still as high as 88% and charge collection efficiency is about 30%.

The Detector Development and Physics Program in sPHENIX Experiment at RHIC

The sPHENIX experiment at RHIC will collect high statistics proton-proton, proton-nucleus and nucleus-nucleus data, starting in the early 2020's. The sPHENIX capabilities enable state-of-the-art studies of jet modification, upsilon suppression and open heavy flavor production to probe the microscopic nature of the strongly-coupled Quark Gluon Plasma, and will allow a broad range of cold QCD studies. The sPHENIX detector will provide precision vertexing, tracking and electromagnetic and hadronic calorimetry in the central pseudorapidity region |η| < 1.1, with full azimuth coverage, at the full RHIC collision rate, delivering unprecedented data sets for hard probe tomography measurements at RHIC. In this talk, we will present a brief overview of the sPHENIX detector design with emphasis on calorimetry. The novel design of the sPHENIX calorimeters includes a tungsten/scintillating fiber electromagnetic calorimeter and two steel/scintillating tile hadronic calorimeter sections. The calorimeter has been optimized for upsilon and jet measurements in the high multiplicity environment of heavy-ion collisions. The design has been simulated in detail using GEANT4, and the simulations have extensively vetted against results obtained from the T-1044 test beam facility at FNAL. Both simulation data and test beam data, and the resulting jet physics performance, will be presented in this talk.

Performance of the CMS Zero Degree Calorimeters in the 2016 pPb run

Two neutral particle detectors, Zero Degree Calorimeters (ZDCs) at the LHC-CMS experiment, cover the |η| > 8.5 region. The ZDCs are Cherenkov calorimeters that use tungsten as the absorber and quartz clad quartz fibers as the active medium. They have a five element electromagnetic section followed by a hadronic section divided into four depth segments. For the 2016 pPb run, the ZDCs were calibrated using test beam data and the single spectator neutron peak at 2.56 TeV. Peaks corresponding to 1, 2 and 3 neutrons are visible in the ZDC total signal distribution. The effect of pileup is corrected by a Fourier deconvolution method. Using this, the spectator neutron number distribution can be unfolded by a linear regularization method. This information serves as a strong constraint to models of pPb collisions and has the potential to produce an unbiased measure of centrality in pPb collisions.

Upgrade of CMS Full Simulation for Run 2

We report on the status of the CMS full simulation software for Run 2 operations of the LHC. Initially, Geant4 10.0p02 was used and about 16 billion events were produced for analysis of 2015-2016 data. In 2017, the CMS detector was updated with a new tracking pixel detector, a modified hadronic calorimeter electronics, and extra muon detectors added. Corresponding modifications were introduced in the full simulation and Geant4 10.2p02 was adopted for 2017 simulation productions; that includes an improved Geant4 for multi-threaded mode, which became the default for 2017. For the 2018 Monte Carlo productions, the full simulation has been updated further. The new Geant4 version 10.4 is used, adopted for the production after detailed validations using test-beam and collision data. The results of validations will be described in details. Several aspects of the migration to Geant4 10.4 and modifications in CMSSW simulation software will be also discussed.

A modular software framework for test-beam data analysis. The TbGaudi package

For purposes of test beam off-line data analysis a modular software framework has been developed and described in theses proceedings. The TbGaudi package allows to handle the test beam data for a set of runs, as well as the set of different devices under test in one-go, and finally obtain an integrated workflow to present the results. All code is written in C++ programming language. A class based design makes it flexible to add any new features of the device under investigation following a plug-in scheme. Currently, the toolkit handles different types of analysis such as charge collection efficiency, track resolution and eta correction, implemented for non-uniform irradiated sensors. The framework is applied for the LHCb upgrade studies for the VELO and UT groups.

Theoretical and experimental study on shear strength of precast steel reinforced concrete beam

With the aim to put forward the analytical model for calculating the shear capacity of precast steel reinforced concrete (PSRC) beams, a static test on two full-scale PSRC specimens was conducted under four-point loading, and the failure modes and strain developments of the specimens were critically investigated. Based on the test results, a modified truss-arch model was proposed to analyze the shear mechanisms of PSRC and cast-in-place SRC beams. In the proposed model, the overall shear capacity of PSRC and cast-in-place SRC beams can be obtained by combining the shear capacity of encased steel shape with web concrete determined by modified Nakamura and Narita model and the shear capacity of reinforced concrete part determined by compatible truss-arch model which can consider both the contributions of concrete and stirrups to shear capacity in the truss action as well as the contribution of arch action through compatibility of deformation. Finally, the proposed model is compared with other models from JGJ 138 and AISC 360 using the available SRC beam test data consisting of 75 shear-critical PSRC and SRC beams. The results indicate that the proposed model can improve the accuracy of shear capacity predictions for shear-critical PSRC and cast-in-place SRC beams, and relatively conservative results can be obtained by the models from JGJ 138 and AISC 360.

Mode I traction-separation measured using rigid double cantilever beam applied to structural adhesive

ABSTRACTAdhesive joining facilitates the development of multi-material vehicle structures; however, widespread adoption requires material properties to characterize adhesive joints for implementation in finite element (FE) models. Specifically, modeling adhesive joints using the cohesive zone method requires measuring the Mode I traction-separation response, which currently requires multiple tests. To address this need, a new method to determine the Mode I response was developed using the Rigid Double Cantilever Beam (RDCB) test, where the steel adherend geometry was designed to ensure high stiffness compared to structural epoxy adhesives. The samples were tested in tension with displacements measured from high-resolution imaging of the test. A new analysis method was developed with resulting Mode I traction-separation response within the expected range for this structural adhesive. The analysis was verified using a FE model of the test and compared to Tapered Double Cantilever Beam test data. Importantly, the predicted force-displacement response from the FE model, using the measured traction-separation curve, compared well to the measured force-displacement data. The proposed RDCB test demonstrated the ability to determine the Mode I response of a toughened structural adhesive using a single test, the results of which can then be readily implemented into FE simulations.

Implementation of the code for the simulation of the response of a triple-GEM tracker and its comparison to the experimental data

In the framework of detector development, Monte Carlo simulations play a key role in the evaluation of the expected performance and the full understanding of the behavior in beam conditions. In particular, a software which simulates the response of the detector to the particle passage is mandatory to test different setups and solutions, such as geometries, fields, voltages etc. and to understand the test beam data. For gas trackers, existing softwares, such as GARFIELD, perform a very detailed simulation of the physical processes but are also CPU time consuming. For the new cylindrical GEM tracker of BESIII, a faster code which models the results obtained from GARFIELD and adapts them to the experimental data, collected in several test beams, has been written. It reproduces the behavior of a planar triple-GEM under different working conditions and, when completed, it will be inserted in the official code of BESIII. A description of the procedure, based on different components (ionization, diffusion and magnetic field, avalanche multiplication, signal induction and readout) will be given and its results will be compared to the GARFIELD simulations and to the experimental data.

IMPACT: An Innovative Tracker and Calorimeter for Proton Computed Tomography

This contribution describes the first results obtained within the iMPACT project, which aims to build a novel proton computed-tomography (pCT) scanner for protons of energy up to 230 MeV, as used in hadron therapy. The iMPACT pCT scanner will improve the current state-of-the-art in proton tracking at all levels: speed, spatial resolution, material budget, and cost. We will first describe the design of the iMPACT scanner, which is composed by a tracker and a range calorimeter. We will then illustrate the results of a test with the ALPIDE sensor, a monolithic active pixels sensor, developed by the ALICE collaboration, which will equip the iMPACT tracker in this first phase. We finally detail the characterization building elements of the prototype of the range calorimeter, which is composed of segmented scintillator fingers readout by SiPMs. Reported beam-test data will highlight how the technological choices we made well address the performances of a state-of-the-art pCT system.

FATALIC: A fully integrated electronics readout for the ATLAS tile calorimeter at the HL-LHC

Abstract The ATLAS Collaboration has started a vast program of upgrades in the context of high-luminosity LHC (HL-LHC) foreseen in 2024. The current readout electronics of every sub-detector, including the Tile Calorimeter, must be upgraded to comply with the extreme HL-LHC operating conditions. The ASIC described in this document, named Front-end ATlAs tiLe Integrated Circuit (FATALIC), has been developed to fulfill these requirements. FATALIC is based on a 130 nm CMOS technology and performs the complete signal processing (amplification, shaping and digitization) over a large dynamic range. A dedicated channel for low current is also designed to perform the detector calibration with a radioactive cesium source. The design and performances of FATALIC are described including test beam data analysis.