The IR-RF alpha-Efficiency of K-feldspar. (15th December 2018)

• Record Type: Journal Article
• Authors: Kreutzer, Sebastian; Martin, Loïc; Dubernet, Stéphan; Mercier, Norbert
• Is Part Of: Radiation measurements. Volume 120(2019:Jan.)
• Page Start: 148
• Page End: 156
• Publication Date: 2018-12-15
• Subjects: Infrared radiofluorescence -- Alpha-efficiency -- Sα-value -- a-value -- K-feldspar -- Fine grain; Nuclear emulsions -- Periodicals; Particle tracks (Nuclear physics) -- Periodicals; Thermoluminescence -- Periodicals; Cosmic rays -- Periodicals; Radiation -- Measurement -- Periodicals; Radiometry -- Periodicals; Radiation Monitoring -- Periodicals; Émulsions nucléaires -- Périodiques; Particules (Physique nucléaire) -- Traces -- Périodiques; Thermoluminescence -- Périodiques; Rayonnement cosmique -- Périodiques; Radiométrie -- Périodiques; 539.77
• DOI: 10.1016/j.radmeas.2018.04.019
• Languages: English
• ISSNs: 1350-4487

Abstract

Abstract: Infrared radiofluorescence (IR-RF) of K-feldspar is an alternative luminescence dating approach to infrared luminescence (IRSL). The application of IR-RF on coarse grain K-feldspar untreated with HF requires knowledge of the IR-RF α-efficiency. We present IR-RF α-efficiency measurements performed on four natural fine grain (4–11 μm) K-feldspar samples and test whether the α-efficiency is similar to that reported for IRSL on polymineral fine grain. The samples originate from Late and Middle Pleistocene aeolian sediment records in France and Germany. The fine grain fraction was obtained by crushing grains of diameter 90–200 μm. The natural signal was reset by optical bleaching at 70 °C using a solar simulator. The α-irradiation was carried out on a home-made α-irradiator, equipped with a 241 Am source. For our irradiation setup, energy spectra were simulated using Geant4 to estimate the particle energy of the incident and exiting α-particles after passing a K-feldspar target. The α-flux induced IR-RF signals show a (super) linear dose-response up to 9.5 × 10 9 (integrated α-flux on the sample). The results indicate no significant difference between the IR-RF α-efficiency of the four samples. An averaged central S α -value of 9.26 ± 1.62 μGy/(10 3 α cm −2 ) (corresponding a -value: 0.067 ± 0.012) was obtained from 84 measurements of all four samples. Our results are similar to a -values reported for IRSL on polymineral fine grain. We finally discuss how the central S α -value can be applied to calculate the β-equivalent α-dose rate of coarse grain mineral extracts. Highlights: Estimation of the alpha-efficiency using IR-RF on fine grain K-feldspar. Simulation of the alpha-particle spectra of the irradiator using Geant4. The alpha-efficiency appears to be similar to the one measured with IRSL.