Publications by Alessandro Mapelli

Measurement of the K+ → π+γγ decay

Alessandro Mapelli, Radoslav Marchevski, Alina Kleimenova

A sample of 3984 candidates of the K+ -> pi(+)gamma gamma decay, with an estimated background of 291 +/- 14 events, was collected by the NA62 experiment at CERN during 2017-2018. In order to describe the observed di-photon mass spectrum, the next-to-leadin ...

Elsevier2024

Microstructured plastic scintillators for pencil beam profiling in proton-therapy accelerators

Alessandro Mapelli, Arnaud Bertsch, Fabrizio Carbone, Simone Gargiulo, Veronica Leccese

A novel beam profiler based on microstructured scintillation resin is presented. The detector consists of a bundle of waveguides, featuring an active area of 30 x 30 mm2 with a fill factor of 50% and a pitch of 400 mu m. This configuration is obtained by c ...

Elsevier2024

Improved calorimetric particle identification in NA62 using machine learning techniques

Alessandro Mapelli, Radoslav Marchevski, Alina Kleimenova

Measurement of the ultra-rare K+ -> pi(+)nu(nu) over bar over bar decay at the NA62 experiment at CERN requires high-performance particle identification to distinguish muons from pions. Calorimetric identification currently in use, based on a boosted decis ...

Springer Nature2023

A study of the K^(+) → π^(0)e^(+)νγ decay

Alessandro Mapelli, Alina Kleimenova, Radoslav Marchevski

A sample of 1.3 x 10^(5) K^(+) → π^(0)e^(+)νγ candidates with less than 1% background was collected by the NA62 experiment at the CERN SPS in 2017-2018. Branching fraction measurements are obtained at percent relative precision in three restricted kinemati ...

Springer Nature2023

Search for K+ decays into the π+e+e-e+e- final state

Alessandro Mapelli, Radoslav Marchevski, Alina Kleimenova

The first search for ultra-rare K+ decays into the pi(+)e(+)e(-) e(+) e(-) final state is reported, using a dataset collected by the NA62 experiment at CERN in 2017-2018. An upper limit of 1.4x10(-8) at 90% CL is obtained for the branching ratio of the K+ ...

Elsevier2023

High-resolution scintillation detector for two-dimensional reconstruction

Alessandro Mapelli, Arnaud Bertsch, Fabrizio Carbone, Veronica Leccese

A scintillation device including a silicon plate having a rectangular shape and having a first side and a second side opposite the first side, wherein the first side includes a plurality of first channels arranged to be in parallel with each other extendin ...

2023

Method for manufacturing an active structure for a radiation detector and polymeric mold for the method

Alessandro Mapelli, Arnaud Bertsch, Fabrizio Carbone, Veronica Leccese

A method for manufacturing a scintillation detector structure including the steps of forming a plurality of first structures into a surface of a substrate to form a patterned substrate, filling the plurality of first structures and covering the surface of ...

2023

Microchannel cooling for the LHCb VELO Upgrade I

Alessandro Mapelli, Giulia Romagnoli, Victor Coco

The LHCb VELO Upgrade I, currently being installed for the 2022 start of LHC Run 3, uses silicon microchannel coolers with internally circulating bi-phase CO2 for thermal control of hybrid pixel modules operating in vacuum. This is the largest scale applic ...

ELSEVIER2022

Transient current technique for charged traps detection in silicon bonded interfaces

Jean-Michel Sallese, Didier Bouvet, Alessandro Mapelli

Wafer bonding is an established technology for the manufacturing of silicon-on-insulator (SOI) substrates, microelectromechanical systems (MEMS) and microfluidic devices. Low temperature direct bonding techniques can be of particular interest for the fabri ...

2019

Differential branching fraction and angular analysis of Lambda(0)(b) -> Lambda mu(+)mu(-) decays

Olivier Schneider, Yiming Li, Guido Haefeli, Aurelio Bay, Christoph Frei, Tatsuya Nakada, Michel De Cian, Frédéric Blanc, Luca Pescatore, Chitsanu Khurewathanakul

Springer Nature2018