Low Gain Avalanche Detectors for the HADES reaction time (T_0) detector upgrade

J Pietraszko,V Kedych,J Michel,S Moneta,A Schemm,Ch Wendisch,A Rost,K Sumara,M Träger,S Linev,W Koenig,C J Schmidt,T Galatyuk,M Traxler,M Koziel,M Kis,W Krüger,R Lalik

doi:10.1140/epja/s10050-020-00186-w

Abstract

Low Gain Avalanche Detector (LGAD) technology has been used to design and construct prototypes of time-zero detector for experiments utilizing proton and pion beams with High Acceptance Di-Electron Spectrometer (HADES) at GSI Darmstadt, Germany. LGAD properties have been studied with proton beams at the COoler SYnchrotron facility in Jülich, Germany. We have demonstrated that systems based on a prototype LGAD operated at room temperature and equipped with leading-edge discriminators reach a time precision below 50 ps. The application in the HADES, experimental conditions, as well as the test results obtained with proton beams are presented.

Highlights

Hardness [9] and low production costs, are very attractive for tracking and timing applications
A demonstration system has been realized as a beam telescope consisting of the two Low Gain Avalanche Detector (LGAD) strip sensors, which was exposed to a proton beam at the COSY Synchrotron at Jülich, Germany
Knowing the exact response of the electronics, as shown in Fig. 5, and knowing the amount of charge generated in the LGAD detector at a gain of 20, it was possible to obtain a relation between the injected charge and the Time over Threshold (ToT) measured in the experiment

Summary

Introduction

The HADES fixed target experiment is located at the SIS18 (heavy-ion synchrotron with rigidity 18 Tm) accelerator in Darmstadt, Germany, and investigates microscopic properties of resonance matter formed in heavy-ion collision in the 1-2A GeV energy regime, as well as exclusive channels in proton and pion beam induced reactions, both for hadronic and semi-leptonic final states. For the physics program of HADES, it is necessary to determine the T0 of the reaction with a precision better than 60 ps (σT0 ) and monitor the properties of the beam, in particular its position, width, and time structure. For the upcoming HADES experiments with pion and proton beams, the T0 detector has to fulfill the following requirements:. Good timing precision with σT0

Experimental Setup

Charge calibration and cluster size analysis

Walk correction

Time precision