A mini X-ray generator as an alternative to a [formula omitted] beta source in luminescence dating

Abstract

We have carried out an investigation to test whether mini X-ray generators are a suitable alternative to radioactive sources in luminescence dating. The study has mainly been motivated by the need for high dose rates (∼1 Gy/ s) to make dating of older samples using regeneration protocols more practical. Furthermore, X-ray generators are more suited for field work and work in countries where regulations restrict the use of radioactive sources. The system tested here (a 50 kV 1 mA Varian VF-50J tube with tungsten target and a matched Spellman high-voltage power supply) was found to provide: (i) excellent linearity between tube current (as set by the user on the control computer) and dose rate, (ii) a wide dynamic range: 2– 30 mGy/ s at 10 kV and 10– 2000 mGy/ s at 50 kV , (iii) short-term stability better than 0.2%, and (iv) a highly uniform irradiation of the sample area. Tests with a sample of thermally sensitized sedimentary quartz suggest that we can use beta and X-ray irradiation interchangeably from the point of view of construction of growth curves by the single-aliquot regenerative-dose protocol.