# VCI2019 - The 15th Vienna Conference on Instrumentation

18-22 February 2019
Vienna University of Technology
Europe/Vienna timezone

## Study on garnet scintillators for TOF-PET detectors and HEP exeriments

Not scheduled
15m
Vienna University of Technology

#### Vienna University of Technology

Gusshausstraße 27-29, 1040 Wien
Board: 59
Poster Medical Applications

### Speaker

Nicolaus Kratochwil (CERN)

### Description

Scintillation crystals are widely used in detectors for high energy physics and medical physics. For positron emission tomography (PET), a major approach to improve the signal to noise ratio and image quality is the time-of-flight technique, where fast scintillators with high stopping power are needed. Particle detectors in future high energy physics experiments will operate at high collision rate in a harsh radiation environment. Coupling radiation tolerant scintillating crystals to silicon photomultiplier provide a flexible option for a precise timing layer in particle detectors, helping in the reconstruction of physics events.

Gadolinium Aluminum Gallium Garnet (GAGG:Ce) scintillators feature high scintillation yield, high density and fast decay time to be competitive with LSO or LYSO. Codoping with divalent ions like $Mg^{2+}$ ions decreases rise and decay time significantly leading to better time resolution.

In this contribution we discuss the timing performance of different codoped GAGG:Ce crystals and the influence of crystal properties, such as density, light yield, decay kinetics and geometry on the timing performance. Samples of LYSO:Ce have also been used as reference time device. Coupled to HPK with 50 $\mu$m SPAD size a CTR of 165 $\pm$ 5 ps (FWHM) for 3x3x5 mm$^3$ GAGG:Ce,Mg,Ti and 130 ps for 2x2x3 mm$^3$ for GAGG:Ce,Mg was measured at E=511 keV.
Timing performance for 100 GeV charged pions traversing pairs of crystals will also be presented.