Mighty Tracker -- Performance Studies of the MightyPix for LHCb

TL;DR

This paper discusses the development and performance evaluation of the MightyPix sensor system for the upcoming Mighty Tracker upgrade at LHCb, focusing on radiation tolerance, timing resolution, and system integration.

Contribution

It introduces the MightyPix sensor and MARS readout system, highlighting their design, radiation resilience, and suitability for high-luminosity LHCb conditions.

Findings

MightyPix sensors achieve radiation tolerance up to 2×10^15 MeVn_eq/cm^2.

Timing resolution of sensors is below 3 ns, compatible with LHCb requirements.

MARS system effectively characterizes sensor performance in laboratory and testbeam environments.

Abstract

A new downstream tracking system, known as the Mighty Tracker, is planned to be installed at LHCb during LS4 of the LHC. This will allow an increase in instantaneous luminosity from $2\cdot10^{33}~\mathrm{cm}^{-2}\mathrm{s}^{-1}$ to $1.5\cdot10^{34}~\mathrm{cm}^{-2}\mathrm{s}^{-1}$ and therefore an overall higher irradiation and up to six times higher occupancy. To keep the material budget as low or even lower as for the current detector, the Mighty Tracker is planned as a hybrid system with silicon pixels in the inner and scintillating fibers in the outer region. For the pixel detector part HV-CMOS MAPS with a pixel size of $55~\mathrm{x}~165~\mathrm{\mu m^2}$ will be used. This technology has been chosen because of its low production costs, low material budget, high radiation tolerance and good timing resolution. To fulfill the requirements, the development and characterization of the sensors focuses on radiation damage with fluences up to $2\cdot10^{15~}\mathrm{MeVn_{eq}}/\mathrm{cm^2}$ and a timing resolution $\leq3~\mathrm{ns}$. The timing resolution is restricted due to the $40~\mathrm{MHz}$ trigger-less DAQ by LHCb. To characterize and further develop the MightyPix a new readout system called MARS (Mighty TrAcker Readout System) has been developed. MARS is a modular system, able to test different single chips in the laboratory as well as at testbeam facilities. It has been used to perform first characterization studies of development-chips investigating radiation tolerance and timing resolution as well as the dependence of the sensor settings on the overall performance.