486 research outputs found

    Search for dark forces at KLOE

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    The existence of a light-dark-force mediator has been tested with the KLOE detector at DAΦNE. This particle, called U, is searched for using the decay chain φ → ηU, with the final state η → π+π− π0, U → e+e−. No evidence is found in 1.5 fb−1 of data. An upper limit on the existence of the U has been set, in the mass range 50 < MU < 420 MeV. We are studying other η dominant decay channels as the 2γ and the 3π0. The combined fit will extend the upper limit on the overall mass range

    QCALT: a tile calorimeter for KLOE-2 upgrade

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    The upgrade of the DAΦ\PhiNE machine layout requires a modification of the size and position of the inner focusing quadrupoles of KLOE-2 thus asking for the realization of two new calorimeters covering the quadrupoles area. To improve the reconstruction of KL2π0K_L\to 2\pi^0 events with photons hitting the quadrupoles a calorimeter with high efficiency to low energy photons (20-300 MeV), time resolution of less than 1 ns and space resolution of few cm, is needed. To match these requirements, we are designing a tile calorimeter, QCALT, where each single tile is readout by mean of SiPM for a total granularity of 2400 channels. We show first tests of the different calorimeter components

    Pre-Production and Quality Assurance of the Mu2e Calorimeter Silicon Photomultipliers

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    The Mu2e electromagnetic calorimeter has to provide precise information on energy, time and position for \sim100 MeV electrons. It is composed of 1348 un-doped CsI crystals, each coupled to two large area Silicon Photomultipliers (SiPMs). A modular and custom SiPM layout consisting of a 3×\times2 array of 6×\times6 mm2^2 UV-extended monolithic SiPMs has been developed to fulfill the Mu2e calorimeter requirements and a pre-production of 150 prototypes has been procured by three international firms (Hamamatsu, SensL and Advansid). A detailed quality assurance process has been carried out on this first batch of photosensors: the breakdown voltage, the gain, the quenching time, the dark current and the Photon Detection Efficiency (PDE) have been determined for each monolithic cell of each SiPMs array. One sample for each vendor has been exposed to a neutron fluency up to \sim8.5~×\times~1011^{11} 1 MeV (Si) eq. n/cm2^{2} and a linear increase of the dark current up to tens of mA has been observed. Others 5 samples for each vendor have undergone an accelerated aging in order to verify a Mean Time To Failure (MTTF) higher than \sim106^{6} hours.Comment: NDIP 2017 - New Developments In Photodetection, 3-7 July 2017, Tours (France