Time Resolution of an Irradiated 3D Silicon Pixel Detector

Christopher Betancourt,Nicola Serra,Giulio Pellegrini,Dario De Simone,Maria Manna,Gregor Kramberger

doi:10.3390/instruments6010012

Abstract

We report on the measurements of time resolution for double-sided 3D pixel sensors with a single cell of 50 μm × 50 μm and thickness of 285 μm, fabricated at IMB-CNM and irradiated with reactor neutrons from 8 ×1014 1MeV neq/cm2 to 1.0 ×1016 1MeV neq/cm2. The time resolution measurements were conducted using a radioactive source at a temperature of −20 and 20 °C in a bias voltage range of 50–250 V. The reference time was provided by a low gain avalanche detector produced by Hamamatsu. The results are compared to measurements conducted prior to irradiation where a temporal resolution of about 50 ps was measured. These are the first ever timing measurements on an irradiated 3D sensor and which serve as a basis for understanding their performance and to explore the possibility of performing 4D tracking in high radiation environments, such as the innermost tracking layers of future high energy physics experiments.

Highlights

The implementation of projects such as the HL-LHC [1] and FCC [2] is closely linked to the refinement of vertex detectors
Environmental conditions at the HL-LHC provide a unique challenge for detector design, where high spatial and temporal resolutions must be maintained in an extreme radiation environment
We investigate whether the radiation hardness of such sensors extends to their timing performance by measuring the time resolution before and after neutron irradiation up to 1.0 × 1016 1MeV neq/cm2

Summary

Introduction

The implementation of projects such as the HL-LHC [1] and FCC [2] is closely linked to the refinement of vertex detectors. 3D silicon pixel detectors are ideal candidates for the innermost layers of vertex trackers due to their inherent radiation hardness [3] and ability to provide time resolutions of the order of tens of picoseconds [4]. This technology, proposed by S.I. Parker and C. Kennedy in 1997 [5], is based on the use of vertical columns of electrodes that penetrate the bulk detector Their particular geometry allows decoupling of the charge collection time and sensor thickness, making them intrinsically radiation tolerant due to the reduced power dissipation, smaller signal rise time and reduced trapping.

Methods

Results

Conclusion