Tl dating labs
The ISGS OSL dating lab is equipped with a Risø TL/OSL-DA-20 Reader; Gamma Spectrometers; two amber light prep labs with fume hoods, shatter box, auto-grinding mortal, dry oven, and furnaces. Above Right: ISGS Risø TL/OSL-DA-20 Reader in dark lab Above Left: ISGS Gamma Spectrometry Lab.
Above Right: Auto-grinding mortal and Merinelli Beaker Above Left: Furnaces and shatter box containers.
TL is only one tool in the investigation of authenticity.
It cannot give the complete picture although it can do many things.
The OSL is further divided, based on the colour (wavelength) of the excitation light source, into Blue Light Stimulated Luminescence (BLSL) and Infrared Stimulated Luminescence (IRSL)Luminescence dating requires a proper resetting of the previously acquired (pre depositional) luminescence in the natural minerals into a very low level (natural zeroing event), either by exposure to sun light during pre-depositional transportation (by wind, water etc.) or by a thermal event (pottery making, baking by lava, fusion crest of meteorites), before deposition.
Following the natural zeroing event and subsequent burial, the natural minerals begin luminescence acquisition afresh from the ionizing radiation (alpha, beta and gamma) constantly provided by the decay of radioactive elements (U238, Th232, K40, Rb) present in the sediments and also from the cosmic rays.
The School of Earth, Atmospheric and Life Sciences (SEALS) is a new school that will serve our communities by integrating environmental sciences research and teaching.
Thermoluminescence (TL) is a faint violet-blue light that is emitted when a piece of fired pottery is heated at a sufficiently high temperature.Raw clay will emit a strong thermoluminescent signal if heated without first being fired in a kiln.However, the act of firing drains away all the geological thermoluminescence acquired over millions of years, essentially setting the dating clock to zero.The amount of TL is measured using a sensitive detector known as a photomultiplier tube.The intensity of the thermoluminescence is proportional to the time that has elapsed since the pottery was removed from the kiln; hence, whereas there is a relatively bright signal from an ancient pottery object, a modern piece of pottery will emit little or no light when it is reheated as only a short time has elapsed since it was fired and there has not been sufficient time for the thermoluminescence to build up to a measurable signal.