Calibration and signal reconstruction in the ATLAS Tile Hadronic calorimeter

International audienceTileCal is the barrel hadronic calorimeter of the ATLAS experiment at LHC/CERN, made of steel and scintillating tiles and read out by optical fibers and photomultiplier tubes. It provides measurements for hadrons, jets and missing transverse energy. The TileCal calibration procedures rely on the performance of dedicated calibration systems: - calibration of the full signal read-out path with movable radioactive 137Cs gamma source; - monitoring of the Photomultiplier tube gains with the laser system; - calibration of the front-end electronic gains with the charge injection system. In this talk we will describe the energy and time calibration procedures used in TileCal to establish the reference detector response and synchronization. We will also discuss the calibration systems performance and the corresponding uncertainties to the energy and timing measurements

Il progetto “ceraNEApolis”: un sistema informativo cartografico delle produzioni ceramiche a Neapolis (IV a.C.-VII d.C.)

In the last few decades, urban archaeology in Naples has contributed to outline the history of the city. The discovery of a great amount of pottery gave information about the daily life of ancient Naples. It was therefore decided to draw up a thematic archaeological map of the ceramics finds to reconstruct their production and distribution from the 4th century B.C. to the 7th century A.D. The project ceraNEApolis consists of a pottery map linked to a bibliographic database, which will be made available online: a working tool for experts, useful to outline the cultural city stratification and to understand the Neapolitan archaeological sites through the material. It is useful in defining the topography of production (workshop, raw materials, and resources), distribution (communication routes, harbour, market), uses and consumption patterns (house, habitat, sacred areas, burials) in the city, even if lacking monumental evidence. It contributes to the reconstruction and analysis of the cultural and urban landscape, taking into account the geomorphological elements and the data contexts even in diachronic and transversal multi-disciplinary perspective. The analysis of some significant cases shows its validity also for potential alternative fruition. The integration of virtual reality systems is a possible extension also for the knowledge, enhancement, communication and use of cultural heritage

Key 19^{19}Ne states identified affecting γ\gamma-ray emission from 18^{18}F in novae

Detection of nuclear-decay $\gamma$ rays provides a sensitive thermometer of nova nucleosynthesis. The most intense $\gamma$-ray flux is thought to be annihilation radiation from the $\beta^+$ decay of $^{18}$F, which is destroyed prior to decay by the $^{18}$F($p$,$\alpha$)$^{15}$O reaction. Estimates of $^{18}$F production had been uncertain, however, because key near-threshold levels in the compound nucleus, $^{19}$Ne, had yet to be identified. This Letter reports the first measurement of the $^{19}$F($^{3}$He,$t\gamma$)$^{19}$Ne reaction, in which the placement of two long-sought 3/2$^+$ levels is suggested via triton-$\gamma$-$\gamma$ coincidences. The precise determination of their resonance energies reduces the upper limit of the rate by a factor of $1.5-17$ at nova temperatures and reduces the average uncertainty on the nova detection probability by a factor of 2.1.Comment: 6 pages, 4 figure

New γ\gamma-ray Transitions Observed in 19^{19}Ne with Implications for the 15^{15}O(α\alpha,γ\gamma)19^{19}Ne Reaction Rate

The $^{15}$O($\alpha$,$\gamma$)$^{19}$Ne reaction is responsible for breakout from the hot CNO cycle in Type I x-ray bursts. Understanding the properties of resonances between $E_x = 4$ and 5 MeV in $^{19}$Ne is crucial in the calculation of this reaction rate. The spins and parities of these states are well known, with the exception of the 4.14- and 4.20-MeV states, which have adopted spin-parities of 9/2$^-$ and 7/2$^-$, respectively. Gamma-ray transitions from these states were studied using triton-$\gamma$-$\gamma$ coincidences from the $^{19}$F($^{3}$He,$t\gamma$)$^{19}$Ne reaction measured with GODDESS (Gammasphere ORRUBA Dual Detectors for Experimental Structure Studies) at Argonne National Laboratory. The observed transitions from the 4.14- and 4.20-MeV states provide strong evidence that the $J^\pi$ values are actually 7/2$^-$ and 9/2$^-$, respectively. These assignments are consistent with the values in the $^{19}$F mirror nucleus and in contrast to previously accepted assignments

Development of the (d,n) proton-transfer reaction in inverse kinematics for structure studies

Transfer reactions have provided exciting opportunities to study the structure of exotic nuclei and are often used to inform studies relating to nucleosynthesis and applications. In order to benefit from these reactions and their application to rare ion beams (RIBs) it is necessary to develop the tools and techniques to perform and analyze the data from reactions performed in inverse kinematics, that is with targets of light nuclei and heavier beams. We are continuing to expand the transfer reaction toolbox in preparation for the next generation of facilities, such as the Facility for Rare Ion Beams (FRIB), which is scheduled for completion in 2022. An important step in this process is to perform the (d,n) reaction in inverse kinematics, with analyses that include Q-value spectra and differential cross sections. In this way, proton-transfer reactions can be placed on the same level as the more commonly used neutron-transfer reactions, such as (d,p), (9Be,8Be), and (13C,12C). Here we present an overview of the techniques used in (d,p) and (d,n), and some recent data from (d,n) reactions in inverse kinematics using stable beams of 12C and 16O.Comment: 9 pages, 4 figures, presented at the XXXV Mazurian Lakes Conference on Physics, Piaski, Polan

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

First Measurement of Coherent Elastic Neutrino-Nucleus Scattering on Argon

We report the first measurement of coherent elastic neutrino-nucleus scattering (\cevns) on argon using a liquid argon detector at the Oak Ridge National Laboratory Spallation Neutron Source. Two independent analyses prefer \cevns over the background-only null hypothesis with greater than $3\sigma$ significance. The measured cross section, averaged over the incident neutrino flux, is (2.2 $\pm$ 0.7) $\times$10$^{-39}$ cm$^2$ -- consistent with the standard model prediction. The neutron-number dependence of this result, together with that from our previous measurement on CsI, confirms the existence of the \cevns process and provides improved constraints on non-standard neutrino interactions.Comment: 8 pages, 5 figures with 2 pages, 6 figures supplementary material V3: fixes to figs 3,4 V4: fix typo in table 1, V5: replaced missing appendix, V6: fix Eq 1, new fig 3, V7 final version, updated with final revision