Optically stimulated luminescence (OSL) and thermoluminescence (TL) methods are commonly used in dosimetry of ionizing radiation and dating of archaeological and geological objects. A typical disadvantage of OSL detectors is signal loss over a longer time scale. In this article, we present a method of studying this phenomenon as well as monitoring the state of the detector by means of optical sampling. The method was used to determine the OSL signal loss (fading) characteristics of selected potassium feldspars.

Post-industrial areas are commonly perceived as degraded and destroyed. In thorough examination one can find how fruitful can be nature left alone with own initiative. Żabie Doły is a territory on the border of Chorzów, Bytom and Piekary Śląskie with status of nature-landscape protected complex. Its core values are habitats of rare species of animals, especially birds. Genesis of the place are the most interesting. Protection is not covering existing remains of natural ecosystems. Site was previously used for agriculture. Its landscape was changed by coal mine activity, exploitation of zinc, lead and brown iron ores. That caused ground subsidence of 5–8 m and appearing of troughs with ground water. Some no longer used railway high embankments are characteristic for the landscape as well as spoil heaps and settling ponds. Soils and pond bottoms are con362 taminated by heavy metals. In spite of the ecologically uneven situation the site is a habitat for many animals protected by national and community law, especially birds. It was confirmed now the presence of 64 species of them, but earlier published sources suggested nearly the twice higher number. There are observed many other animals, European hamster among them. Local flora collect 375 species. Valorisation done in 2016 was basic source for development plan prepared in 2017 for part of area within Bytom borders. Żabie Doły is the site of “intertwined worlds” of natural habitats, recreation, fishing, bird watching and ecological events. Present tendencies in nature protection imply the way of revitalization enhancing nature popularization. So overlap of functional layers was supported by specific infrastructure and new “world” of virtual reality was added to attract young generations.