Time and band-resolved scintillation in time projection chambers based on gaseous xenon

Abstract

We present a systematic study of the time and band-resolved scintillation in xenon-based time projection chambers (TPCs), performed simultaneously for the primary (S1) and secondary (S2) components in a small, purity-controlled, setup. We explore a range of conditions of general academic interest, focusing on those of relevance to contemporary TPCs: pressure range ([1- 10] bar), pressure-reduced electric fields ([0-100] V/cm/bar in the drift region (S1) and up to the proportional scintillation regime in the multiplication region (S2)), wavelength-band ([145-250], [250-400], [400-600] nm), and primary excitation ($α$, $β$-particles). Attention is paid to the possibility of non-conventional scintillation mechanisms such as the 3rd continuum emission, recombination light from $β$-electrons at high pressure (for S1), emission from high-lying excited states and neutral bremsstrahlung (for S2). Time constants and, specially, scintillation yields have been obtained as a function of electric field and pressure, the latter aided by Geant4 simulations.