Standard bialkaline photomultipliers (PMT) and EMI 9235QB PMTs do not detect emissions beyond 650 nm, whereas electron multiplying CCD (EMCCD) cameras can capture the whole range (modified after Ref. (a) When using the additive dose method, incremental doses are administered on top of the natural dose and then measured.
(b) With the regenerative dose approach, samples are first zeroed to remove any previously acquired dose and then given incremental doses, followed by measuring.
Headlines lauded the work for rewriting our history; for filling gaps in the evolutionary record, while others claimed it had the potential to upend everything we know about our cultures and behaviours. Now, following the discovery of a second remote cave chamber on the site where the original remains were found, the story has taken a twist.
(b) At appropriate sites, electrons are trapped while holes may become localized.
(c) Thermal (TL) or optical (OSL) stimulation of the material results in electrons being evicted from the traps.
Evicted electrons that reach luminescence centers result in light being emitted. Illustration of glow-curves obtained following thermal stimulation. For quartz, TL measurement focused on a peak between 320 and 330°C whereas for feldspar, a peak at 310–320°C was analyzed.
(a) A signal yielded after the first heating of a quartz sample with trapped electrons (paleodose). Detection of TL signals was through a window with a center at 400 nm (violet).
Advanced dating techniques suggest Homo naledi was much younger than thought and may have lived alongside Homo sapiens – the first time it has been demonstrated that another species of hominin survived in Africa.