492 research outputs found
Search for dark forces at KLOE
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
The upgrade of the DANE 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 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
The Mu2e electromagnetic calorimeter has to provide precise information on
energy, time and position for 100 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 32 array of
66 mm 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 8.5~~10 1 MeV (Si) eq.
n/cm 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 10
hours.Comment: NDIP 2017 - New Developments In Photodetection, 3-7 July 2017, Tours
(France
Inference-Based Decisions in a Hidden State Foraging Task:Differential Contributions of Prefrontal Cortical Areas
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