We derive a method to improve particle identification (PID) at high transverse momentum ($p_T$) using the relativistic rise of the ionization energy loss ($rdE/dx$) when charged particles traverse the Time Projection Chamber (TPC) at STAR. Electrons triggered and identified by the Barrel Electro-Magnetic Calorimeter (BEMC), pure protons and pions from $Λ\to p+π^{-}$ ($\barΛ\to \bar{p}+π^{+}$), and $K^{0}_{S}\toπ^{+}+π^{-}$ decays are used to obtain the $dE/dx$ value and its width at given $βγ=p/m$. We found that the deviation of the $dE/dx$ from the Bichsel function can be up to $0.4σ$ ($\sim3%$) in p+p collisions at $\sqrt{s_{NN}}=200$ GeV taken and subsequently calibrated in year 2005. The deviation is approximately a function of $βγ$ independent of particle species and can be described with a function of $f(x) = A+\frac{B}{C+x^{2}}$. The deviations obtained with this method are used to re-calibrate the data sample from p+p collision for physics analysis of identified hadron spectra and their correlations up to transverse momentum of 15 GeV/$c$. The ratio of $e^{-}/e^{+}$ (dominantly from $γ$-conversion) is also used to correct the residual asymmetry in the negative and positive charged hadrons due to momentun distortion in the STAR TPC.
In the HARP experiment the large-angle spectrometer is using a cylindrical TPC as main tracking and particle identification detector. The momentum scale of reconstructed tracks in the TPC is the most important systematic error for the majority of kinematic bins used for the HARP measurements of the double-differential production cross-section of charged pions in proton interactions on nuclear targets at large angle. The HARP TPC operated with a number of hardware shortfalls and operational mistakes. Thus it was important to control and characterize its momentum calibration. While it was not po…
ALICE (A Large Heavy Ion Experiment) is one of the four major experiments at the Large Hadron Collider (LHC) at CERN, which is today the most powerful particle accelerator worldwide. The High Level Trigger (HLT) is an online compute farm of about 200 nodes, which reconstructs events measured by the ALICE detector in real-time. The HLT uses a custom online data-transport framework to distribute data and workload among the compute nodes. ALICE employs several calibration-sensitive subdetectors, e.g. the TPC (Time Projection Chamber). For a precise reconstruction, the HLT has to perform the calib…
In the upcoming LHC Run 3, starting in 2021, the upgraded Time Projection Chamber (TPC) of the ALICE experiment will record minimum bias Pb-Pb collisions in a continuous readout mode at an interaction rate up to 50 kHz. This corresponds to typically 4-5 overlapping collisions during the electron drift time in the detector. Despite careful tuning of the new quadruple GEM-based readout chambers, which fulfill the design requirement of an ion backflow below 1%, these conditions will lead to space-charge distortions of several centimeters that fluctuate in time. They will be corrected via a calibr…
ALICE (A Large Ion Collider Experiment) is one of four major experiments at the Large Hadron Collider (LHC) at CERN. The High Level Trigger (HLT) is a compute cluster, which reconstructs collisions as recorded by the ALICE detector in real-time. It employs a custom online data-transport framework to distribute data and workload among the compute nodes. ALICE employs subdetectors sensitive to environmental conditions such as pressure and temperature, e.g. the Time Projection Chamber (TPC). A precise reconstruction of particle trajectories requires the calibration of these detectors. Performing …
The ALICE experiment will run with continuous readout at interaction rates of up to 50 kHz in Pb-Pb collisions during Run 3 of the LHC. In order to achieve this goal, a new data processing scheme and software are developed. This scheme strongly relies on GPUs (Graphics Processing Unit) for fast online and offline calibration and reconstruction as well as on efficient data compression. On the hardware side, the Time Projection Chamber (TPC), among other detector systems, received major upgrades to its readout chambers and readout electronics. The multiwire proportional chambers were replaced by…
ALICE (A Large Heavy Ion Experiment) is one of the four large scale experiments at the Large Hadron Collider (LHC) at CERN. The High Level Trigger (HLT) is an online computing farm, which reconstructs events recorded by the ALICE detector in real-time. The most compute-intense task is the reconstruction of the particle trajectories. The main tracking devices in ALICE are the Time Projection Chamber (TPC) and the Inner Tracking System (ITS). The HLT uses a fast GPU-accelerated algorithm for the TPC tracking based on the Cellular Automaton principle and the Kalman filter. ALICE employs gaseous s…
We propose a new technique for the calibration of nuclear recoils in large noble element dual-phase time projection chambers used to search for WIMP dark matter in the local galactic halo. This technique provides an $\textit{in situ}$ measurement of the low-energy nuclear recoil response of the target media using the measured scattering angle between multiple neutron interactions within the detector volume. The low-energy reach and reduced systematics of this calibration have particular significance for the low-mass WIMP sensitivity of several leading dark matter experiments. Multiple strategi…
The Time Projection Chamber is the main tracking and particle identification detector of the ALICE experiment. The high luminosities delivered by the CERN LHC in Run 2 (2015-2018) posed new challenges in terms of detector performance and efficiency. The hardware components and calibration software were optimized and further developed to meet those challenges and maximize the quality of the data. In addition, unexpectedly large local distortions of the drift paths of ionization electrons have been observed at the edges of specific readout chambers. These distortions are caused by ions which ori…
A Time Projection Chamber (TPC) is a powerful detector for 3-dimensional tracking and particle identification for ultra-high multiplicity events. It is the central tracking device of many experiments, e.g. the ALICE experiment at CERN. The necessity of a switching electrostatic gate, which prevents ions produced in the amplification region o MWPCs from entering the drift volume, however, restricts its application to trigger rates of the order of 1 kHz. Charge amplification by Gas Electron Multiplier (GEM) foils instead of proportional wires offers an intrinsic suppression of the ion backflow, …
A number of liquid argon time projection chambers (LAr TPC's) are being build or are proposed for neutrino experiments on long- and short baseline beams. For these detectors a distortion in the drift field due to geometrical or physics reasons can affect the reconstruction of the events. Depending on the TPC geometry and electric drift field intensity this distortion could be of the same magnitude as the drift field itself. Recently, we presented a method to calibrate the drift field and correct for these possible distortions. While straight cosmic ray muon tracks could be used for calibration…
The design, construction, and commissioning of the ALICE Time-Projection Chamber (TPC) is described. It is the main device for pattern recognition, tracking, and identification of charged particles in the ALICE experiment at the CERN LHC. The TPC is cylindrical in shape with a volume close to 90 m^3 and is operated in a 0.5 T solenoidal magnetic field parallel to its axis. In this paper we describe in detail the design considerations for this detector for operation in the extreme multiplicity environment of central Pb--Pb collisions at LHC energy. The implementation of the resulting requiremen…
A dual-phase xenon time-projection chamber was built at Nikhef in Amsterdam as a direct dark matter detection R&D facility. In this paper, the setup is presented and the first results from a calibration with a $^{22}$Na gamma-ray source are presented. The results show an average light yield of (5.6 $\pm$ 0.3) photoelectrons/keV (calculated to 122 keV and zero field) and an electron lifetime of (429 $\pm$ 26) $μ$s. The best energy resolution $σ_E/E$ is (5.8 $\pm$ 0.2)% at an energy of 511 keV. This was achieved using a combination of the scintillation and the ionization signals. A photomultipli…
In LHC Run 3, ALICE will increase the data taking rate significantly to 50\,kHz continuous read out of minimum bias Pb-Pb events. This challenges the online and offline computing infrastructure, requiring to process 50 times as many events per second as in Run 2, and increasing the data compression ratio from 5 to 20. Such high data compression is impossible by lossless ZIP-like algorithms, but it must use results from online reconstruction, which in turn requires online calibration. These important online processing steps are the most computing-intense ones, and will use GPUs as hardware acce…
The ALICE experiment at the Large Hadron Collider at CERN is upgrading its central tracking detector, the Time Projection Chamber (TPC). The installation is foreseen during the second long shutdown of the Large Hadron Collider. The upgrade includes the complete exchange of the present MWPC readout chambers (ROC) with new ones based on Gas Electron Multiplier detectors. This is necessary due to the higher LHC luminosity and thus higher interaction rate. The new ROCs allow for continuous readout at 50 kHz compared to 500 Hz of the gated MWPC readout, while maintaining the particle identification…
This paper presents the Forward Time Projection Chamber (FTPC) system of the NA61/SHINE experiment at the CERN SPS accelerator. This TPC system applies a novel tandem-TPC design to reduce the background originating from particle tracks not synchronous with the event trigger. The FTPC system is composed of three chambers with alternating drift field directions. The chambers were installed directly along the beamline region of the NA61/SHINE detector in a medium- to high-intensity (10-100 kHz) hadron or ion beam. The tandem TPC system has proved to be capable of rejecting out-of-time background …
The calibration procedure of a finely granulated digital hadron calorimeter with Resistive Plate Chambers as active elements is described. Results obtained with a stack of nine layers exposed to muons from the Fermilab test beam are presented.
After the Long Shutdown 2 the LHC will provide lead-lead collisions at interaction rates as high as 50kz. In order to cope with such conditions the ALICE Time Projection Chamber (TPC) needs to be upgraded. After the upgrade the TPC will run in a continuous mode, without any degradation of the momentum and dE/dx resolution compared to the performance of the present TPC. Since readout by multi-wire proportional chambers is no longer feasible with these requirements, new technologies have to be employed. In the new readout chambers the electron amplification is provided by a stack of four Gas Ele…
The T2K experiment is designed to study neutrino oscillation properties by directing a high intensity neutrino beam produced at J-PARC in Tokai, Japan, towards the large Super-Kamiokande detector located 295 km away, in Kamioka, Japan. The experiment includes a sophisticated near detector complex, 280 m downstream of the neutrino production target in order to measure the properties of the neutrino beam and to better understand neutrino interactions at the energy scale below a few GeV. A key element of the near detectors is the ND280 tracker, consisting of two active scintillator-bar target sys…
A new type of Time Projection Chamber (TPC) has been proposed for the upgrade of the ALICE (A Large Ion Collider Experiment at CERN) so as to cater to the high luminosity environment expected at the Large Hadron Collider (LHC) facility in future. This device will rely on the intrinsic ion back flow (IBF) suppression of Micro-Pattern Gas Detectors (MPGD) based technology in particular the Gas Electron Multiplier (GEM). GEM is to minimise the space charge effect in the main drift volume and thus will not require the standard gating grid and the resulting intrinsic dead time. It will thus be poss…
The large CALICE Digital Hadron Calorimeter prototype (DHCAL) was built in 2009 - 2010. The DHCAL uses Resistive Plate Chambers (RPCs) as active media and is read out with 1 x 1 cm2 pads and digital (1 - bit) resolution. With a world record of about 0.5M readout channels, the DHCAL offers the possibility to study hadronic interactions with unprecedented spatial resolution. This talk reports 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.
The kaon identification is crucial for the flavor physics, and also benefits the flavor and charge reconstruction of the jets. We explore the particle identification capability for tracks with momenta ranging from 2-20 GeV/c using the $dE/dx$ measurements in the Time Projection Chamber at the future Circular Electron-Positron Collider. Based on Monte Carlo simulation, we anticipate that an average $3.2~σ$ ($2.6~σ$) $K/π$ separation can be achieved based on $dE/dx$ information for an optimistic (conservative) extrapolation of the simulated performance to the final system. Time-of-flight (TOF) i…
ALICE is the dedicated heavy-ion experiment at the CERN Large Hadron Collider (LHC). Its main tracking and particle-identification detector is a large volume Time Projection Chamber (TPC). The TPC has been designed to perform well in the high-track density environment created in high-energy heavy-ion collisions. In this proceeding, we describe the track reconstruction procedure in ALICE. In particular, we focus on the two main challenges that were faced during the Run 2 data-taking period (2015--2018) of the LHC, which were the baseline fluctuations and the local space charge distortions in th…
The CALICE collaboration has constructed highly granular electromagnetic and hadronic calorimeter prototypes to evaluate technologies for the use in detector systems at the future International Linear Collider. These calorimeters have been tested extensively in particle beams at CERN and at Fermilab. We present analysis results for hadronic events recorded at CERN with a SiW ECAL, a scintillator tile HCAL and a scintillator strip tail catcher, the latter two with SiPM readout, focusing both on the HCAL alone and on the complete calorimeter setup. Particular emphasis is placed on the study of t…
We report on the construction, tests, calibrations and commissioning of an Optical Readout Time Projection Chamber (O-TPC) detector operating with a CO2(80%) + N2(20%) gas mixture at 100 and 150 Torr. It was designed to measure the cross sections of several key nuclear reactions involved in stellar evolution. In particular, a study of the rate of formation of oxygen and carbon during the process of helium burning will be performed by exposing the chamber gas to intense nearly mono-energetic gamma-ray beams at the High Intensity Gamma Source (HIgS) facility. The O-TPC has a sensitive target-dri…
The CALICE collaboration investigates diferent technology options for highly granular calorimeters for detectors at a future electron-positron collider. One of the devices constructed and tested by this collaboration is a 1m3 prototype of a scintillator-steel sampling calorimeter for hadrons with analogue readout (AHCAL). The light from 7608 small scintillator cells is detected with silicon photomultipliers. The AHCAL has been successfully operated during electron and hadron test-beam measurements at DESY, CERN, and Fermilab since 2005. One of main tasks for the successful data taking is to es…
The Analogue Hadron Calorimeter (AHCAL) is being developed within the CALICE collaboration for experiments at a future lepton collider. It is a sampling calorimeter with alternating layers of steel absorber plates and plastic scintillator tiles as active material. In the SiPM on tile design, the tiles are directly coupled to silicon photomultipliers (SiPMs). The front-end electronics are integrated into the active layers of the calorimeter. They are designed for low power consumption by rapidly power cycling according to the beam structure of a linear accelerator. In 2017 and 2018, a new large…
A performance evaluation of superconducting transition-edge sensors (TESs) in the environment of a pion beam line at a particle accelerator is presented. Averaged across the 209 functioning sensors in the array, the achieved energy resolution is 5.2 eV FWHM at Co $K_α$ (6.9 keV) when the pion beam is off and 7.3 eV at a beam rate of 1.45 MHz. Absolute energy uncertainty of $\pm$0.04 eV is demonstrated for Fe $K_α$ (6.4 keV) with in-situ energy calibration obtained from other nearby known x-ray lines. To achieve this small uncertainty, it is essential to consider the non-Gaussian energy respons…
The Compact Muon Solenoid (CMS) detector is one of two general-purpose detectors that reconstruct the products of high energy particle interactions at the Large Hadron Collider (LHC) at CERN. The silicon pixel detector is the innermost component of the CMS tracking system. It determines the trajectories of charged particles originating from the interaction region in three points with high resolution enabling precise momentum and impact parameter measurements in the tracker. The pixel detector is exposed to intense ionizing radiation generated by particle collisions in the LHC. This irradiation…
A new method for calibrating the hadron response of a segmented calorimeter is developed. It is based on a principal component analysis of the calorimeter layer energy deposits, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the ATLAS calorimeters were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion…
Methods are presented for calibrating the hadron calorimeter system of the CMS detector at the LHC. The hadron calorimeters of the CMS experiment are sampling calorimeters of brass and scintillator, and are in the form of one central detector and two endcaps. These calorimeters cover pseudorapidities $|η| <$ 3 and are positioned inside a solenoidal magnet. An outer calorimeter, outside the magnet coil, covers $|η| <$ 1.26, and a steel and quartz-fiber Cherenkov forward calorimeter extends the coverage to $|η| <$ 5.19. The initial calibration of the calorimeters was based on results from test b…
The CALICE collaboration is developing an engineering prototype of an analog hadron calorimeter for a future linear collider detector. The prototype has to prove the feasibility of building a realistic detector with fully integrated front-end electronics. The performance goals are driven by the requirement of high jet energy resolution and the measurement of the details of the shower development. The signals are sampled by small scintillating plastic tiles that are read out by silicon photomultipliers. The ASICs are integrated into the calorimeter layers and are optimized for minimal power con…
The jet calibration of the Liquid-Argon-Calorimeter of the H1 Detector at HERA is described. In the measurement of high jet transverse energies systematic uncertainties as low as 2% can be reached in deep inelastic scattering with a high photon virtuality (Q^2) and in photoproduction. Furthermore, the concept of a new energy weighting scheme of H1 is presented. First applications with a high Q^2 neutral current deep inelastic scattering sample show that the resolution of the balance in transverse momentum between the hadronic system and the electron is improved.
The design of detector concepts has been driven for a long time by requirements on transverse momentum, impact parameter and jet energy resolutions, as well as hermeticity. Only rather recently it has been realised that the ability to idenfity different types of charged hadrons, in particular kaons and protons, could have important applications at Higgs factories like the International Linear Collider (ILC), ranging from improvements in tracking, vertexing and flavour tagging to measurements requiring strangeness-tagging. While detector concepts with gaseous tracking, like a time projection ch…
The design of detector concepts has been driven for a long time by requirements on transverse momentum, impact parameter and jet energy resolutions, as well as hermeticity. Only rather recently it has been realised that the ability to idenfity different types of charged hadrons, in particular kaons and protons, could have important applications at Higgs factories like the International Linear Collider (ILC), ranging from improvements in tracking, vertexing and flavour tagging to measurements requiring strangeness-tagging. While detector concepts with gaseous tracking, like a time projection ch…
There is described the design of the FODS hadron calorimeters, the procedure of the calibration and the results of the calorimeter study with electron and pion beams.
The Inner Tracking System is the ALICE detector closest to the beam axis. It is composed of six layers of silicon detectors: two innermost layers of Silicon Pixel Detectors (SPD), two intermediate layers of Silicon Drift Detectors (SDD) and two outermost layers of Silicon Strip Detectors (SSD). The ITS can be used as a standalone tracker in order to recover tracks that are not reconstructed by the Time Projection Chamber (TPC) and to reconstruct low momentum particles with $p_{t}$ down to 100 MeV/c. Particle identification in the ITS is performed by measuring the energy loss signal in the SDD …
We present studies of proton fluxes in the T10 beamline at CERN. A prototype high pressure gas time projection chamber (TPC) was exposed to the beam of protons and other particles, using the 0.8 GeV/c momentum setting in T10, in order to make cross section measurements of low energy protons in argon. To explore the energy region comparable to hadrons produced by GeV-scale neutrino interactions at oscillation experiments, i.e., near 0.1 GeV of kinetic energy, methods of moderating the T10 beam were employed: the dual technique of moderating the beam with acrylic blocks and measuring scattered p…
The high flux of charged particles interacting with the CMS Forward Hadron Calorimeter PMT windows introduced a significant background for the trigger and offline data analysis. During Long Shutdown 1, all of the original PMTs were replaced with multi-anode, thin window photomultiplier tubes. At the same time, the back-end electronic readout system was upgraded to μTCA readout. The experience with commissioning and calibration of the Forward Hadron Calorimeter is described as well as the μTCA system. The upgrade was successful and provided quality data for Run 2 data-analysis at 13 TeV.
The Compact Muon Solenoid (CMS) is one of two general-purpose detectors that reconstruct the products of high energy particle interactions at the Large Hadron Collider at CERN. The silicon pixel detector is the innermost component of the CMS tracking system. It determines the trajectories of charged particles originating from the interaction region with high resolution enabling precise momentum and impact parameter measurements in the tracker. It is designed to operate in the high particle density environment of the LHC. The calibration of the pixel detector plays an important role in its perf…
Calibration of the discriminator threshold of the Amplifier-Shaper-Discriminator Chip for the Upgrade of the ATLAS Muon Drift-Tube Chambers for the High-Luminosity LHC
