Characteristics of the quartz isothermal thermoluminescence (ITL) signal from the 375 °C peak and its potential for extending the age limit of quartz dating. (February 2023)

• Record Type: Journal Article
• Authors: Rahimzadeh, Neda; Zhang, Junjie; Tsukamoto, Sumiko; Long, Hao
• Is Part Of: Radiation measurements. Volume 161(2022)
• Publication Date: 2023-02
• Subjects: Isothermal thermoluminescence (ITL) -- Natural dose response curve -- Multiple aliquot methods -- Age underestimation -- Pulsed-irradiation -- Luochuan loess; 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.2022.106899
• Languages: English
• ISSNs: 1350-4487

Abstract

Abstract: The quartz isothermal thermoluminescence (ITL) signal measured at 330 °C (ITL330 ) has been proposed as a method to measure deep traps in quartz, i.e., 375 °C TL peak, therefore offering the potential to extend the dating limit of quartz. However, little is known about the applicability of this signal for dating. We therefore investigate the characteristics of the ITL330 signal, in terms of the origin of the signal, thermal stability, and bleachability. Since the trapping sensitivity changes induced by high temperature treatments undermine the application of the single aliquot regenerative dose (SAR) protocol, here we evaluate the reliability and applicability of the multiple aliquot methods, i.e., multiple aliquot additive dose (MAAD) and multiple aliquot regenerative dose (MAR) protocols, using samples from the Luochuan section on the Chinese Loess Plateau with the independent age control. Results indicate that the ITL330 signal is closely associated with the 375 °C peak of the glow curve, originating from a deep trap at about 1.8 eV with a thermal lifetime of ∼10 10 years at 10 °C. The natural ITL330 dose response curve (DRC) indicates the signal has a theoretical dating range up to ∼800 Gy, equivalent to ∼230 ka. When the natural DRC is compared with the laboratory generated DRCs using MAR and MAAD protocols, they start to diverge in shape after ∼200 Gy, resulting in significant ITL330 age underestimation beyond ∼70 ka. However, application of the pulsed-irradiation (PI) method for the MAAD protocol reveals that the shape of the natural DRC can mostly be reproduced with the PI-MAAD protocol and thus it can provide reliable ages up to natural saturation at ∼230 ka. While further investigations are required to assess the impact of the repeated pulse irradiation and heating on the signal and determine the optimal pulsed irradiation conditions, it appears that this approach can be a promising step forward to provide a better simulation of the trapping conditions in nature. Highlights: The ITL330 signal originates from a deep trap at about 1.8 eV with a thermal lifetime of ∼10 10 years at 10 °C. The natural ITL330 DRC indicates that the signal has a theoretical dating range up to ∼800 Gy, equivalent to ∼230 ka. Natural and laboratory generated DRCs (MAR and MAAD) deviate at about ∼200 Gy. Pulsed-irradiation (PI) method reduces the shape dissimilarity between natural and regenerated MAAD DRCs. The PI-MAAD protocol can provide reliable ages up to natural saturation at ∼230 ka.