Characterisation of Large Area THGEMs and Experimental Measurement of the Townsend Coefficients for CF${}_4$

Abstract

Whilst the performance of small THGEMs is well known, here we consider the challenges in scaling these up to large area charge readouts. We first verify the expected gain of larger THGEMs by reporting experimental Townsend coefficients for a 10 cm diameter THGEM in low-pressure CF${}_4$. Large area 50 cm by 50 cm THGEMs were sourced from a commercial PCB supplier and geometrical imperfections were observed which we quantified using an optical camera setup. The large area THGEMs were experimentally characterised at Boulby Underground Laboratory through a series of gain calibrations and alpha spectrum measurements. ANSYS, Magboltz and Garfield++ simulations of the design of a TPC based on the large area THGEMs are presented. We also consider their implications for directional dark matter research and potential applications within nuclear security.

arXiv comment18 pages, 22 figures

References in corpus (3)

• A concise review on THGEM detectors
• The novel properties of SF${}_6$ for directional dark matter experiments
• Establishment of Imaging Spectroscopy of Nuclear Gamma-Rays based on Geometrical Optics

Cited by in corpus (4)

• Electron Transport in Gaseous Detectors with a Python-based Monte Carlo Simulation Code
• The Thick Gas Electron Multiplier and its derivatives: physics, technologies and applications
• Demonstration of ThGEM-Multiwire Hybrid Charge Readout for Directional Dark Matter Searches
• Performance of 20:1 multiplexer for large area charge readouts in directional dark matter TPC detectors