Studies on the thermoluminescence depth profile produced by 600-MeV protons in artificial lunar soil

The thermoluminescence (TL) of various plagioclase feldspars embedded in a thick target of 150 kg of artificial lunar soil was measured after a 600-MeV proton irradiation. No correlation was observed between the parameters of the characteristic feldspar glow peak and the anorthite contents. The relative TL sensitivities of the individual plagioclase variants were measured and found to be practically the same for⁶⁰Co-γ- and 600-MeV proton-irradiated samples.The TL intensity distribution within the target arrangement, converted to a 2π isotropic p-influx, resulted in an approximate TL depth profile of a thermally undisturbed lunar soil bomarded by galactic cosmic protons. The undisturbed TL intensity at a depth of 28 g/cm² (? 17 cm) decreased to 39% at a depth of 106 g/cm² (? 60 cm). For the evaluation of the temperature gradients by TL in lunar samples the experimental data at the sites of Taurus-Littrow and of Hadley-Rille yielded minimum depth intervals for sampling of ～ 20 cm and ～ 40 cm respectively, presuming an error of ± 15% in the TL determination. Certain aspects are seen by using the relation TL intensity/²²Na-activity ratio versus depth (thus representing the total ionization profile) to establish²²Na depth profiles.