Characterization and Performance of PADME's Cherenkov-Based Small-Angle Calorimeter

Abstract

The PADME experiment, at the Laboratori Nazionali di Frascati (LNF), in Italy, will search for invisible decays of the hypothetical dark photon via the process $e^{+}{e}^{-}\to \gamma A^{\prime }$, where the $A^{\prime }$ escapes detection. The dark photon mass range sensitivity in a first phase will be 1 to 24 MeV. We report here on measurement and simulation studies of the performance of the Small-Angle Calorimeter, a component of PADME's detector dedicated to rejecting 2- and 3-gamma backgrounds. The crucial requirement is a timing resolution of less than 200 ps, which is satisfied by the choice of PbF${}_2$ crystals and the newly released Hamamatsu R13478UV photomultiplier tubes (PMTs). We find a timing resolution of 81 ps (with double-peak separation resolution of 1.8 ns) and a single-crystal energy resolution of 5.7%/$\sqrt{E}$ with light yield of 2.07 photo-electrons per MeV, using 100 to 400 MeV electrons at the Beam Test Facility of LNF. We also propose the investigation of a two-PMT solution coupled to a single PbF${}_2$ crystal for higher-energy applications, which has potentially attractive features.

arXiv comment12 pages, 19 figures. v2: added section on radiation damage studies

References in corpus (5)

• The Beam and detector of the NA62 experiment at CERN
• Proposal to search for a dark photon in $e^{+}$ on target collisions at DA$\Phi$NE linac
• Studies of an array of PbF2 Cherenkov crystals with large-area SiPM readout
• Realtime calibration of the A4 electromagnetic lead fluoride calorimeter
• Electron beam test of key elements of the laser-based calibration system for the muon $g$ $-$ $2$ experiment

Cited by in corpus (5)

• QED Meson Description of the X17 and Other Anomalous Particles
• Characterisation and performance of the PADME electromagnetic calorimeter
• Commissioning of the PADME experiment with a positron beam
• Using Artificial Intelligence in the Reconstruction of Signals from the PADME Electromagnetic Calorimeter
• The CRILIN calorimeter: gamma radiation resistance of crystals and SiPMs