The NA62 GigaTracker

G Aglieri Rinella,M Perrin-Terrin,J Degrange,E Minucci,S Bonacini,F Petrucci,A Cotta Ramusino,D Alvarez Feito,R Arcidiacono,L Perktold,P Petagna,K Poltorak,M Fiorini,A Gianoli,M Noy,G Ruggiero,H Wahl,C Biino,S Chiozzi,F Marchetto,B Velghe,A Mapelli,E Cortina Gil,A Ceccucci,E Gamberini,Michel Morel ,J.p Noel ,Giulia Romagnoli ,J Kapłon ,Alexander Kluge

doi:10.1016/j.nima.2016.06.045

Abstract

The GigaTracker is a hybrid silicon pixel detector built for the NA62 experiment aiming at measuring the branching fraction of the ultra-rare kaon decay K+→π+νν¯ at the CERN SPS. The detector has to track particles in a beam with a flux reaching 1.3MHz/mm2 and provide single-hit timing with 200ps RMS resolution for a total material budget of less than 0.5% X0 per station. The tracker comprises three 60.8mm×27mm stations installed in vacuum (∼10−6mbar) and cooled with liquid C6F14 circulating through micro-channels etched inside a few hundred micron thick silicon plates. Each station is composed of a 200μm thick silicon sensor read out by 2×5 custom 100μm thick ASICs, called TDCPix. Each chip contains 40×45 asynchronous pixels, 300μm×300μm each and is instrumented with 100ps bin time-to-digital converters. In order to cope with the high rate, the TDCPix is equipped with four 3.2Gb/s serialisers sending out the data. We will describe the detector and the results from the 2014 and 2015 NA62 runs.

Highlights

Beam imaging is an important tool in accelerator based physics experiments
The LHCb Vertex Locator (VELO) is an important instrument in the measurement of the luminosity with both van der Meer method (VdM) and beam–gas imaging method (BGI) methods
The BGI method [3], which premiered at LHCb, takes advantage of beam–gas interactions inside the VELO into which gas is injected

Summary

Introduction

Beam imaging is an important tool in accelerator based physics experiments. Measured parameters for single beam diagnostics are among others the position of the colliding beams in the accelerator, the transverse and longitudinal beam profile as well as the beam intensity. The LHCb experiment [2] at the CERN Large Hadron Collider (LHC) is a forward detector that was designed to study particles containing b or c quarks. It consists of several sub-systems, like the vertex locator (VELO), ring imaging Cherenkov detectors, a dipole magnet, further tracking detectors, a calorimeter system and a muon identification system. The LHCb VELO is an important instrument in the measurement of the luminosity with both VdM and BGI methods. Its resolution plays a crucial role in the BGI method

Results of the BGI method

Limitations of the VELO BGI method

The beam gas vertex detector – BGV

Current status of the BGV

Summary