Intense infrared scintillation of liquid Ar-Xe mixtures

Abstract

Abstract. Intense infrared (IR) light emission from liquid Ar-Xe mixtures has been observed using 12 keV electron-beam excitation. The emission peaks at a wavelength of 1.18 µm and the half-width of the emission band is 0.1 µm. Maximum intensity has been found for a 10 ppm xenon admixture in liquid argon. The conversion efficiency of electron beam-power to IR-light is about 1 % (10000 photons per MeV electron energy deposited). A possible application of this intense IR emission for a new particle discrimination concept in liquid noble gas detectors is discussed. No light emission was found for perfectly purified liquid argon in the wavelength range from 0.5 to 3.5 µm on the current level of sensitivity.

Near-infrared scintillation of liquid argon: recent results obtained with the NIR facility at Fermilab

“…The Munich group continued their studies now with an improved purification system added to their apparatus [23] and the possibility of adding Xe in a controlled way, with the result that they no longer see any relevant emission in pure liquid argon in the range 500 to 3,000 nm [23]. They therefore revise their previous result ( [16], [19]) stating that they now believe the observed signal was an "artifact due to the normalization of the spectrum with the response function of the spectrometer used for that spectral range" [23]. .…”

Intense vacuum ultraviolet and infrared scintillation of liquid Ar-Xe mixtures

“…In addition to the VUV, an IR emission is formed at ∼ 1.18 µm peak wavelength (see ref. [12] for details). Note the wide wavelength range in a logarithmic representation from 115 nm to 3.5 µm and the differently scaled ordinates for the VUV and the IR parts of the measurement.…”

“…The emission spectra from 115 nm to 500 nm were measured with a photomultiplier with S20 cathode operated in photon counting mode. The wavelength range from 500 nm to 3.5 µm was scanned with an InAs infrared photodiode [12]. The small peak at 149 nm in the upper panel is caused by a residual xenon impurity which could not be removed completely.…”

“…Our present interest in the emission spectra of xenondoped liquid argon comes from a recent discovery of a strong emission from this medium in the infrared (IR) at ∼ 1.18µm peak wavelength [12]. Since two parallel optical signals could improve the discrimination power of an event-by-event particle identification in a scintillation detector, we studied the corresponding emission spectrum in a Andreas Ulrich: andreas.ulrich@ph.tum.de the VUV for the xenon concentration of 10 ppm.…”

Near-infrared scintillation of liquid argon

“…More recently, the Munich group has published new results of their on-going studies of the scintillation of pure liquid argon and liquid Ar-Xe mixtures, stating that they no longer see any relevant emission in pure liquid argon in the range 500 to 3,000 nm [23]. They therefore revise their previous result ( [19,20]) saying that they now believe the observed signal was an "artifact due to the normalization of the spectrum with the response function of the spectrometer used for that spectral range".…”