The Risø single grain OSL attachment enables routine measurements of sand-sized single grains of minerals. Individual sand-sized grains are placed in special aluminium discs containing 100 holes, 300 μm deep by 300 μm in diameter, on a 10 by 10 grid with 600 μm spacing between hole centres. Irradiation and heating can thus be performed simultaneously on all 100 grains, whereas the OSL signal can be measured separately from individual grains by using a focused laser.
The single grain attachment is available in two versions:
Single laser single grain attachment:
Attachment for measuring OSL from single grains (size 180-250 µm) of samples. The unit is based on a focused solid-state green laser beam and an X-Y scanning device using movable mirrors mounted on software controlled encoded motorised linear stages. The Laser is a green (532 nm), 10 mW stabilised DPSS laser. The green laser stimulation light can be ramped by software to perform LM-OSL on single grains. The sample is loaded into special aluminium discs each containing 100 individual grain holes (ø = 300 µm).
Dual laser single grain attachment:
Attachment for measuring OSL from single grains (size 180-250 µm) of samples. The unit is based on two (green and IR) focused laser beams and an X-Y scanning device using movable mirrors mounted on software controlled encoded motorised linear stages. The lasers are a green (532 nm), 10 mW stabilised DPSS laser and an IR diode (830 nm), 140 mW TTL modulated laser. The green and IR laser stimulation light can be ramped by software to perform LM-OSL from single grains. The sample is loaded into special aluminium discs each containing 100 individual grain holes (ø = 300 µm). 50 such single grain discs are included in the delivery.
The IR and green laser stimulation can be used in any measurement sequence e.g. for screening of feldspar contaminated quartz grains or simply for IR stimulation of single feldspar grains.
These attachments include a special IRSL/OSL stimulation head enabling IR/Blue light stimulation of multiple grain samples. This special IRSL/OSL stimulation head makes use of the same diodes and provide the same power densities on the sample as the standard IRSL/OSL stimulation head. But as it is designed to accommodate the single grain attachment as well, the light collection efficiency is reduced by approximately 40%..