Blake, A. and Devitt, D. and Lister, A. and Nowak, J. and Thorpe, C. (2021) Measurement of the Longitudinal Diffusion of Ionization Electrons in the MicroBooNE Detector. Journal of Instrumentation, 16 (9): P09025. ISSN 1748-0221
Diffusion_Paper_Draft_v6.1.pdf - Accepted Version
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Abstract
Accurate knowledge of electron transport properties is vital to understanding the information provided by liquid argon time projection chambers (LArTPCs). Ionization electron drift-lifetime, local electric field distortions caused by positive ion accumulation, and electron diffusion can all significantly impact the measured signal waveforms. This paper presents a measurement of the effective longitudinal electron diffusion coefficient, $D_L$, in MicroBooNE at the nominal electric field strength of 273.9 V/cm. Historically, this measurement has been made in LArTPC prototype detectors. This represents the first measurement in a large-scale (85 tonne active volume) LArTPC operating in a neutrino beam. This is the largest dataset ever used for this measurement. Using a sample of $\sim$70,000 through-going cosmic ray muon tracks tagged with MicroBooNE's cosmic ray tagger system, we measure $D_L = 3.74^{+0.28}_{-0.29}$ cm$^2$/s.