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.
For calculating the age, the radiation energy stored in the mineral (known as Paleodose) and the annual radioactivity rate (annual dose) from the surrounding sediments has to be calculated.
It is recognised as one of the world’s leading archaeological dating laboratories, based on its track record of using OSL dating to answer internationally significant questions in archaeology and palaeoanthropology.
Some natural materials such as various stones and soils (and also things made from them, such as pottery and stone tools) absorb or 'trap' naturally occurring electrons from their surroundings.
This happens at a known and regular rate until the material becomes saturated with electrons after about 50,000 years.
The OSL dating laboratory is also at the forefront of technical advances in the analysis and interpretation of OSL data collected from single sand-sized grains of quartz, building on the pioneering research of Roberts and Jacobs in this field.
The new, state-of-the-art laboratory consists of separate rooms for the preparation and measurement of quartz and feldspar grains, as well as storage rooms for quarantined material.
The time elapsed since sedimentation, i.e., Age = Paleodose Annual Dose In practice, the paleodose is calculated by measuring the luminescence intensity in the natural mineral and regenerate the equivalent luminescence intensity by artificial radiation dose from a calibrated beta source attached to the TL/OSL instrument.
For calculating the annual dose rate, the elemental concentration of U, Th and K (by XRF or ICP-MS) in the sediment and water content in the sediment are required.
Some soils can have their electron 'clocks' reset simply by being exposed to sunlight.
If they are then buried beneath later deposits, they begin to trap electrons again and can be dated by similar methods (OSL).
THAI Royal First Class, Royal Silk Class passengers and Star Alliance Gold passengers flying on any Star Alliance flights are entitled to use THAI lounges at Suvarnbhumi Airport where they can relax or work while waiting for their flights to depart. ST means Reservation Status which are; OK means You are confirmed on this flight. Answer Passenger may request infant meal before departure not less than 48 hours for international flights.
There are seven locations for THAI Departure Lounges. Royal First Lounge at concourse D has been allocated for First Class passengers with the capacity to accommodate 134 passengers at one time. You can request from TG office at first boarding point for infant age from 6-10 months.
All rooms are fitted with safelights, similar to a photographic darkroom.