Limits of a spatial resolution of the cascaded GEM based detectors

V. N. Kudryavtsev, T. V. Maltsev, L. I. Shekhtman

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Spatial resolution of tracking detectors based on GEM cascades is determined in the simulation and measured. The simulation includes GEANT4 implemented transport of high energy electrons with careful accounting for atomic relaxation processes including emission of fluorescent photons and Auger electrons and custom post-processing taking into account diffusion, gas amplification fluctuations, the distribution of signals over readout electrodes, electronics noise and particular algorithm of final coordinate calculation (centre-of-gravity algorithm). The simulation demonstrates that the minimum of the spatial resolution of about 10-20 μm can be achieved with a gas mixture of Ar-CO2 (75%-25%) at a strip pitch in the range from 250 μm to 300 μm. At a larger pitch the resolution quickly degrades reaching 70-100 μm at a pitch of 450-500 μm. The reasons of such behavior are discussed and corresponding hypothesis is tested. Particularly, the effect of electron cloud modification due to a GEM operation is considered using the ANSYS and Garfield++ simulation programs. The detection efficiency and spatial resolution of low-material triple-GEM detectors for the DEUTERON facility at BINP are measured at the extracted beam facility of the VEPP-4M collider. One-coordinate resolution of two detectors for the DEUTERON facility is measured with a 2 GeV electron beam. The determined values of the detectors' spatial resolution is equal to 46.6 ± 0.1 μm and 38.5 ± 0.2 μm for orthogonal tracks in two detectors, respectively.

Original languageEnglish
Article number06015
Number of pages9
JournalJournal of Instrumentation
Volume12
Issue number6
DOIs
Publication statusPublished - 19 Jun 2017

Keywords

  • Detector modelling and simulations II (electric fields, charge transport, multiplication and induction, pulse formation, electron emission, etc)
  • Electron multipliers (gas)
  • Gaseous detectors
  • Gaseous imaging and tracking detectors
  • pulse formation, electron emission, etc)
  • Detector modelling and simulations II (electric fields, charge transport, multiplication, and induction

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