The RICH detector of the NA62 experiment at CERN

D Aisa,V Carassiti,E Iacopini,C Campeggi,F Bucci,P Cenci,L Farnesini,A Piluso,S Lami,G Anzivino,P Wertelaers,A Bizzetti,M Lenti ,F Maletta ,R Piandani ,M Piccini ,Thomas Schneider ,V Duk ,A Sergi ,R Ciaranfi ,J R Fry ,J R Fry ,C Santoni ,Antonio Cassese ,M Pepé

doi:10.1016/j.nima.2014.06.089

Abstract

The NA62 experiment at CERN aims to measure the branching ratio of the ultra-rare charged kaon decay K+→π+νν¯ with a 10% accuracy and with a background contamination at the 10% level. Since the branching ratio of this decay is O(10−10), to fulfill such request one of the main backgrounds, the decay K+→μ+ν (BR~63%), must be suppressed by a rejection factor of 4×10−13 (assuming 10% signal acceptance). This can be partially accomplished using a combination of kinematical cuts (8×10−6) and the different power of penetration through matter of pions and muons (10−5). A further 5×10−3 suppression factor will be provided by a RICH detector, in a momentum range between 15 and 35GeV/c. The details of the RICH project as well as the results from test runs performed on a RICH prototype of the same length of the final detector will be presented. The current status of the construction and the description of the final readout and trigger electronics will also be reviewed.

Highlights

The NA62 experiment at CERN aims to measure the branching ratio of the ultra-rare charged kaon decay K+ → π+ννwith a 10% accuracy and with a background contamination at the 10% level
A further 5×10−3 suppression factor will be provided by a RICH detector, in a momentum range between 15 and 35 GeV/c
The details of the RICH project as well as the results from test runs performed on a RICH prototype of the same length of the final detector will be presented

Summary

Introduction

The NA62 experiment [1] at CERN will start to take data in fall 2014 to measure the branching ratio of the ultra-rare charged kaon decay K+ → π+νν with a 10% accuracy and with a background contamination at the 10% level. The downstream RICH detector will be fundamental to suppress the background from decays with a muon in the final state (mainly K+ → μ+ν). The RICH will allow to reject muons contaminating the pion sample with a suppression factor of the order of 5 × 10−3 in a momentum range between 15 27 and 35 GeV/c. The RICH detector must provide the pion crossing time 28 with a resolution of the order of 100 ps to minimize wrong matching with the decaying kaon measured by an upstream detector. The RICH will stand a rate of about 10 MHz and will be a key element of the NA62 trigger system

The NA62 RICH

Results from tests

Status of the construction