Response evolution of the CMS ECAL and R&amp;amp;D studies for electromagnetic calorimetry at the high-luminosity LHC

Nessi‐Tedaldi, F.

doi:10.1109/nssmic.2012.6551434

Cited by 8 publications

(5 citation statements)

References 16 publications

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“…Therein, we have shown how Lead Tungstate (PbWO 4 ) exposed to hadronic showers from high-energy protons [1] and pions [3] experiences a cumulative loss of Light Transmission which is permanent at room temperature, while no hadron-specific change in scintillation emission [2] was observed. The amplitude of the damage can reach values unsuitable for running at the HL-LHC [6,7]. A microscopic investigation [4] has allowed us to ascribe the dominant damage mechanism to heavy fragments arising from Lead and Tungsten fission, which deposit a lot of energy along their short track, leaving regions within the crystal where the lattice structure is modified and left disturbed, strained, disordered, or re-oriented.…”

Section: Introductionmentioning

confidence: 99%

Results on damage induced by high-energy protons in LYSO calorimeter crystals

Dissertori

Luckey

Nessi‐Tedaldi

et al. 2014

Nuclear Instruments and Methods in Physics Research Section A:

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Lutetium-Yttrium Orthosilicate doped with Cerium (LYSO:Ce), as a bright scintillating crystal, is a candidate for calorimetry applications in strong ionizing-radiation fields and large high-energy hadron fluences as are expected at the CERN Large Hadron Collider after the planned High-Luminosity upgrade. There, proton-proton collisions will produce fast hadron fluences up to ∼ 5 × 10 14 /cm 2 in the large-rapidity regions of the calorimeters.The performance of LYSO:Ce has been investigated, after exposure to different fluences of 24 GeV/c protons. Measured changes in optical transmission as a function of proton fluence are presented, and the evolution over time due to spontaneous recovery at room temperature is studied.The activation of materials will also be an issue in the described environment. Studies of the ambient dose induced by LYSO and its evolution with time, in comparison with other scintillating crystals, have also been performed through measurements and FLUKA simulations.submitted to Elsevier for publication in Nucl. Instr. and Meth. in Phys. Research A arXiv:1309.3872v2 [physics.ins-det]

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Section: Introductionmentioning

confidence: 99%

Results on damage induced by high-energy protons in LYSO calorimeter crystals

Dissertori

Luckey

Nessi‐Tedaldi

et al. 2014

Nuclear Instruments and Methods in Physics Research Section A:

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“…The slope of the light collection efficiency as a function of depth, at the time when the ECAL was constructed, is taken to be −0.14 ± 0.08%/X 0 [29,30], for the front half of the crystal ("front nonuniformity"). The change of this slope, ∆F, is parametrized as a function of the absorption coef-ficient induced by irradiation measured in m −1 , ∆µ, and is given by ∆F = 0.4% × ∆µ/X 0 [31]. Finally, the induced absorption coefficient is related to the light-yield (LY) loss measured by the laser monitoring system, ∆(LY/LY 0 ), through ∆µ = k × ∆(LY/LY 0 ), where k = 0.02%/m (i.e.…”

Section: Energy Scale Uncertaintymentioning

confidence: 99%

Section: Cmsmentioning

confidence: 99%

Performance of photon reconstruction and identification with the CMS detector in proton-proton collisions at √s= 8 TeV

Khachatryan¹,

Sirunyan²,

Tumasyan³

et al. 2015

J. Inst.

210

250

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A description is provided of the performance of the CMS detector for photon reconstruction and identification in proton-proton collisions at a centre-of-mass energy of 8 TeV at the CERN LHC. Details are given on the reconstruction of photons from energy deposits in the electromagnetic calorimeter (ECAL) and the extraction of photon energy estimates. The reconstruction of electron tracks from photons that convert to electrons in the CMS tracker is also described, as is the optimization of the photon energy reconstruction and its accurate modelling in simulation, in the analysis of the Higgs boson decay into two photons. In the barrel section of the ECAL, an energy resolution of about 1% is achieved for unconverted or late-converting photons from H → γγ decays. Different photon identification methods are discussed and their corresponding selection efficiencies in data are compared with those found in simulated events.The central feature of the CMS apparatus is a superconducting solenoid of 6 m internal diameter, providing a magnetic field of 3.8 T. Within the superconducting solenoid volume are a silicon pixel and strip tracker, a lead tungstate crystal electromagnetic calorimeter, and a brass/scintillator hadron calorimeter (HCAL), each one composed of a barrel and two endcap sections. Muons are measured in gas-ionization detectors embedded in the steel flux-return yoke outside the solenoid. Extensive forward calorimetry complements the coverage provided by the barrel and endcap detectors. A more detailed description of the CMS detector can be found in Ref. [1].The pseudorapidity coordinates, η, of detector elements are measured with respect to the coordinate system origin at the centre of the detector, whereas the pseudorapidity of reconstructed particles and jets is measured with respect to the interaction vertex from which they originate. Photon reconstruction Photon reconstructionPhotons for use as signals or signatures in measurements and searches, rather than for use in the construction of jets or missing transverse energy, are reconstructed from energy deposits in the ECAL using algorithms that constrain the clusters to the size and shape expected for electrons and photons with p T 15 GeV. The algorithms do not use any hypothesis as to whether the particle originating from the interaction point is a photon or an electron, consequently electrons from Z → e + e − events, for which pure samples with a well defined invariant mass can be selected, can provide excellent measurements of the photon trigger, reconstruction, and identification efficiencies, and of the photon energy scale and resolution. The reconstructed showers are generally limited to a fiducial region excluding the last two crystals at each end of the barrel (|η| < 1.4442). The outer circumferences of the endcaps are obscured by services passing between the barrel and the endcaps, and this area is removed from the fiducial region by excluding the first ring of trigger towers of the endcaps (|η| > 1.566). The fiducial region terminates at |η| = 2.5...

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“…Total cross section measurements reveal in fact that different hadron types interact similarly in crystalline matter at high energies [7]. In parallel, it became possible to draw predictions from data taken in situ for the CMS ECAL detector longevity [8,9] which led to the decision to replace its endcaps in view of the LHC upgrade for high-luminosity running (HL-LHC) [10]. The predictions have recently been confirmed by observations of signal losses in the CMS ECAL that are by now quite significant, especially in the most exposed, high-η regions of the detector [11].…”

Section: Introductionmentioning

confidence: 99%

A FLUKA study towards predicting hadron-specific damage due to high-energy hadrons in inorganic crystals for calorimetry

Dissertori¹,

Perez²,

Nessi‐Tedaldi³

2020

J. Inst.

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Hadrons emerging from high-energy collisions, as it is the case for protons and pions at the CERN Large Hadron Collider, can produce a damage to inorganic crystals that is specific and cumulative. The mechanism is well understood as due to bulk damage from fragments caused by fission. In this paper, the existing experimental evidence for lead tungstate, LYSO and cerium fluoride is summarised, a study using FLUKA simulations is described and its results are discussed and compared to measurements. The outcome corroborates the confidence in the predictive power of such simulations applied to inorganic scintillators, which are relevant to their adoption as scintillators for calorimetry.

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Response evolution of the CMS ECAL and R&D studies for electromagnetic calorimetry at the high-luminosity LHC

Cited by 8 publications

References 16 publications

Results on damage induced by high-energy protons in LYSO calorimeter crystals

Results on damage induced by high-energy protons in LYSO calorimeter crystals

Performance of photon reconstruction and identification with the CMS detector in proton-proton collisions at √s= 8 TeV

A FLUKA study towards predicting hadron-specific damage due to high-energy hadrons in inorganic crystals for calorimetry

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