Tetraphenyl-butadiene films: VUV-Vis optical characterization from room to liquid argon temperature

Francini, R.; Montereali, Rosa Maria; Nichelatti, E.; Vincenti, M. A.; Canci, N.; Segreto, E.; Cavanna, F.; Pompeo, Francesco; Carbonara, F.; Fiorillo, G.; Perfetto, F.

doi:10.1088/1748-0221/8/09/c09010

Cited by 20 publications

(39 citation statements)

References 11 publications

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“…Fig. 15 presents optical spectra of the PMT Quantum Efficiency (QE) [52,53], SiPM Photon Detection Efficiency (PDE) [35,52,54], transmittance of the ordinary and UV acrylic plate in front of the SiPM and 1PMT, respectively, and WLS hemispherical transmittance [55]. In addition, the emission spectrum of the WLS [51] is presented.…”

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

“…Regarding the conversion efficiency of the TPB-based WLS, in our previous works [16,18] we used CE = 0.58 around 128 nm [51], CE = 0.40 at 300-400 nm [51,55,57] and CE = 0 above 400 nm. However, the TPB conversion efficiency at 128 nm has recently been significantly revised towards a decrease [58]: the correction factor reached 2.…”

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

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Revealing neutral bremsstrahlung in two-phase argon electroluminescence

Shemyakina

Bondar

Dolgov

et al. 2018

Astroparticle Physics

164

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Proportional electroluminescence (EL) in noble gases has long been used in two-phase detectors for dark matter search, to record ionization signals induced by particle scattering in the noble-gas liquid (S2 signals). Until recently, it was believed that proportional electroluminescence was fully due to VUV emission of noble gas excimers produced in atomic collisions with excited atoms, the latter being in turn produced by drifting electrons. In this work we consider an additional mechanism of proportional electroluminescence, namely that of bremsstrahlung of drifting electrons scattered on neutral atoms (so-called neutral bremsstrahlung); it is systemically studied here both theoretically and experimentally. In particular, the absolute EL yield has for the first time been measured in pure gaseous argon in the two-phase mode, using a dedicated two-phase detector with EL gap optically read out by cryogenic PMTs and SiPMs. We show that the neutral bremsstrahlung effect can explain two intriguing observations in EL radiation: that of the substantial contribution of the non-VUV spectral component, extending from the UV to NIR, and that of the photon emission at lower electric fields, below the Ar excitation threshold. Possible applications of neutral bremsstrahlung effect in two-phase dark matter detectors are discussed.

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Section: Experimental Setup and Proceduresmentioning

confidence: 99%

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

Revealing neutral bremsstrahlung in two-phase argon electroluminescence

Shemyakina

Bondar

Dolgov

et al. 2018

Astroparticle Physics

164

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show abstract

“…Here N e is the charge expressed in the number of electrons, drifting in the EL gap and producing proportional electroluminescence. Figure 2 presents optical spectra of the PMT Quantum Efficiency (QE) [20,21], MPPC Photon Detection Efficiency (PDE) [16,20], acrylic plate transmittance (measured by us) and WLS (TPB in polystyrene) hemispherical transmittance [22]. In addition, the EL emission spectrum of Ar doped with N 2 , namely the 2PS spectrum [7], and the emission spectrum of the WLS (TPB in polystyrene) [23] are presented.…”

Section: Experimental Setup and Measurement Proceduresmentioning

confidence: 99%

Further studies of proportional electroluminescence in two-phase argon

Bondar¹,

Dolgov²,

Frolov³

et al. 2017

J. Inst.

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A: The study of proportional electroluminescence in two-phase argon is relevant in the field of noble-gas liquid detectors for dark matter search and low-energy neutrino experiments. In this work, we continued to study proportional electroluminescence (EL) in two-phase argon doped with a minor (9 ppm) admixture of nitrogen, in the VUV, UV and visible spectral ranges. We confirmed the effect of enhancement of the EL yield, as well as the presence of non-VUV component in addition to that of VUV, in proportional electroluminescence in two-phase Ar. On the other hand, the contribution of non-VUV component determined here within the model of N 2 emission in the UV, turned out to be insufficient to explain the EL yield enhancement effect. Accordingly, the problem of proportional electroluminescence in two-phase Ar remains unresolved.

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“…1. TPB is used as a wavelength shifter in noble gas detectors (NEXT [3], ArDM [4]) due to the short scintillation wavelengths of the noble gases (128 nm for Ar, 172 nm for Xe). It is used as a coating for the active surface of the photosensors and the internal walls of the detectors.…”

Section: Introductionmentioning

confidence: 99%

Ageing studies of TPB in noble gas detectors for dark matter and neutrinoless ββ decay searches

Yahlali

Garcia

Díaz

et al. 2017

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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Noble gases (Xe, Ar, Kr) are very attractive as detector media in Dark Matter search and neutrinoless double-beta decay experiments. However, the detection of their scintillation light (in the VUV spectral region) requires shifting the VUV light to visible light, where standard photosensors are more efficient. Tetraphenyl butadiene (TPB) is widely used as wavelength shifter, absorbing the VUV light and re-emitting in the blue region (~430 nm). TPB is an organic molecule that may degrade due to exposure to environmental agents and also to ultraviolet light. In this work, we present TPB ageing studies due to exposure to VUV light, aiming at quantifying the reduction of the absolute fluorescence yield of TPB coatings of several thicknesses (130 nm, 260 nm, 390 nm, 1600 nm), exposed to various doses of VUV light at 170 nm (similar to the Xe scintillation). In our setup, the VUV light is produced from a vacuum monochromator coupled to a deuterium lamp. The VUV exposure in our setup is compared to the exposure obtained in the electroluminescent gaseous Xe TPC of the NEXT-100 experiment for neutrinoless double-beta decay search.

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Tetraphenyl-butadiene films: VUV-Vis optical characterization from room to liquid argon temperature

Cited by 20 publications

References 11 publications

Revealing neutral bremsstrahlung in two-phase argon electroluminescence

Revealing neutral bremsstrahlung in two-phase argon electroluminescence

Further studies of proportional electroluminescence in two-phase argon

Ageing studies of TPB in noble gas detectors for dark matter and neutrinoless ββ decay searches

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