Narrow Results

The RD52 (DREAM) collaboration is performing R&D on dual readout calorimetry techniques with the aim of improving hadronic energy resolution for future high energy physics experiments. The simultaneous detection of Cherenkov and scintillation light enables us to measure the electromagnetic fraction of hadron shower event-by-event. As a result, we could eliminate the main fluctuation which prevented from achieving precision energy measurement for hadrons. We have tested the performance of the lead and copper fiber prototypes calorimeters with various energies of electromagnetic particles and hadrons. During the beam test, we investigated the energy resolutions for electrons and pions as well as the identification of those particles in a longitudinally unsegmented calorimeter. Measurements were also performed on pure and doped PbWO₄ crystals, as well as BGO and BSO, with the aim of realizing a crystal based dual readout detector. We will describe our results, focusing on the more promising properties of homogeneous media for the technique. Guidelines for additional developments on crystals will be also given. Finally we discuss the construction techniques that we have used to assemble our prototypes and give an overview of the ones that could be industrialized for the construction of a full hermetic calorimeter.

The knowledge of the initial flux, energy and flavor of current neutrino beams is the main limitation for a precise measurement of neutrino cross-sections. The ENUBET ERC project is studying a facility based on a narrow-band neutrino beam capable of constraining the neutrino fluxes normalization through the monitoring of the associated charged leptons in an instrumented decay tunnel. In ENUBET, the identification of large-angle positrons from $K_{e3}$ decays at single particle level can potentially reduce the ${\nu }_e$ flux uncertainty at the level of 1%. This setup would allow for an unprecedented measurement of the ${\nu }_e$ cross-section at the GeV scale. This input would be highly beneficial to reduce the budget of systematic uncertainties in the next long baseline oscillation projects. Furthermore, in narrow-band beams, the transverse position of the neutrino interaction at the detector can be exploited to determine a priori with significant precision the neutrino energy spectrum without relying on the final state reconstruction. This contribution will present the advances in the design and simulation of the hadronic beam line. Special emphasis will be given to a static focusing system of secondary mesons that can be coupled to a slow extraction proton scheme. The consequent reduction of particle rates and pile-up effects makes the determination of the ${\nu }_{\mu }$ flux through a direct monitoring of muons after the hadron dump viable, and paves the way to a time-tagged neutrino beam. Time-coincidences among the lepton at the source and the neutrino at the detector would enable an unprecedented purity and the possibility to reconstruct the neutrino kinematics at source on an event-by-event basis. We will also present the performance of positron tagger prototypes tested at CERN beamlines, a full simulation of the positron reconstruction chain and the expected physics reach of ENUBET.

During years 2011 and 2012 data taking runs have been carried out at VEPP-2000 e⁺e^- collider to measure the production of the nucleon-antinucleon pairs near threshold. In this talk the preliminary results on the nucleon timelike electromagnetic form factors (FF) and the |G_E/G_M| ratio are presented.

The ATLAS detector trigger system needs to reduce the incoming rate of 40 MHz at design luminosity to around 200 Hz. The access to detector information must be fast so that trigger algorithms can run within a very short time budget (40ms at Level-2 and ≈ 4s at Event Filter). This work presents the modifications implemented to the calorimeter software data preparation which resulted in a gain of almost six times in data unpacking processing speed. Application to cosmic rays acquisition is also shown.

The Multi-Pixel Photon Counter (MPPC) is a novel semiconductor photon sensor belonging to the Pixelated Photon Detector (PPD) family, which also includes the Silicon-Photomultiplier. Since it has many remarkable features, we are studying and developing the MPPC, aiming to utilize it to read out a strip-scintillator calorimeter for a future linear collider experiment. We have measured the gain and photon detection efficiency of the 1600 pixel MPPC, which are comparable to the performance of conventional photomultipliers, and its dark noise rate and cross-talk, which are acceptably small. The dynamic range, a weak point of the MPPC, is confirmed to be enhanced thanks to a short recovery time. After ensuring the acceptable performance of 1600 pixel MPPCs, we built a calorimeter test module with a scintillator-strip structure and full MPPC readout, and exposed it to positron beams to evaluate its performance. Results of the beam test show good performance of the calorimeter prototype. These results indicate that the MPPC is a promising device not only for calorimeter readout, but also for photon detection in various other fields.

The RD52 (DREAM) collaboration is performing R&D on dual readout calorimetry techniques with the aim of improving hadronic energy resolution for future high energy physics experiments. The simultaneous detection of Cherenkov and scintillation light enables us to measure the electromagnetic fraction of hadron shower event-by-event. As a result, we could eliminate the main uctuation which prevented from achieving precision energy measurement for hadrons. We have tested the performance of the lead and copper fiber prototypes calorimeters with various energies of electromagnetic particles and hadrons. During the beam test, we investigated the energy resolutions for electrons and pions as well as the identification of those particles in a longitudinally unsegmented calorimeter. Measurements were also performed on pure and doped PbWO₄ crystals, as well as BGO and BSO, with the aim of realizing a crystal based dual readout detector. We will describe our results, focusing on the more promising properties of homogeneous media for the technique. Guidelines for additional developments on crystals will be also given. Finally we discuss the construction techniques that we have used to assemble our prototypes and give an overview of the ones that could be industrialized for the construction of a full hermetic calorimeter.

The Liquid Argon (LAr) calorimeter provides electromagnetic and forward hadronic calorimetry for the ATLAS experiment at the LHC. Since the installation of the calorimeter in 2006, the electronic calibration and readout systems have been exercised with regular calibration and cosmic runs, and with three days of LHC single beam runs. These datasets have enabled detailed studies of calibration procedures, pulse shape models, uniformity of response, detector noise, and the possibility of noise and cosmic rays as backgrounds to jet and missing energy measurements. They have allowed a precise understanding of the detector behavior. The LAr calorimeter is well prepared for LHC collisions, which we hope for by the end of 2009.