Table 4. SAR protocols used in this study to obtain ages from quartz (protocol A) and K-feldspars (protocol B).
| A | B | ||||
| Step | Single-grain TT-OSL SAR protocol | Step | SAR pIR-IR multi-grain aliquots | ||
| 1a | Give dose | 1a | Give dose | ||
| 2 | Preheat to 260°C for 10 s | 2 | Preheat to 250°C for 60 s | ||
| 3 | Stimulate with green laser at 125°C for 2 s (90% power) | 3 | Stimulate with infrared diodes 50°C for 200 s (90% power) | ||
| 4 | Preheat to 260°C for 10 s | 4b | Stimulate with infrared diodes 225°C for 200 s (90% power) | pIR-IR | |
| Ln or Lx | |||||
| 5 | Stimulate with green laser at 125°C for 2 s (90% power) | TT-OSL | 5 | Give test dose (100 Gy) | |
| Ln or Lx | |||||
| 6 | Stimulate with blue LEDs at 280°C for 400 s | 6 | Preheat to 250°C for 60 s | ||
| 7 | Give test dose (200–300 Gy) | 7 | Stimulate with infrared diodes 50°C for 200 s (90% power) | ||
| 8 | Preheat to 260°C for 10 s | 8b | Stimulate with infrared diodes 225°C for 200 s (90% power) | pIR-IR | |
| Tn or Tx | |||||
| 9 | Stimulate with green laser at 125°C for 2 s (90% power) | 9c | Return to 1 | ||
| 10 | Preheat to 260°C for 10 s | ||||
| 11 | Stimulate with green laser at 125°C for 2 s (90% power) | TT-OSL | |||
| Tn or Tx | |||||
| 12 | Stimulate with blue LEDs at 290°C for 400 s | ||||
| 13 | Return to 1 |
Ln and Lx refer to the natural and regenerative-dose signal measurements, respectively. Tn and Tx refer to the test dose signals measured after the Ln and Lx signals, respectively. Each SAR measurement cycle was repeated for the natural-dose, three to four different sized regenerative doses, a 0 Gy regenerative-dose (to measure OSL signal recuperation) and a replicate of the first regenerative-dose cycle (to assess the suitability of the test-dose sensitivity correction). In the case of the single-grain TT-OSL SAR procedure, the OSL IR depletion ratio [124] was measured separately and used to check for the presence of feldspar contaminants.
Step omitted when measuring the natural signal (Ln).
Aliquots were held at pIR-IR stimulation temperatures for 10 s prior to switching on the IR diodes to avoid any potential isothermal TL contamination of the pIR-IR signal.
A high temperature IRSL stimulation was not included at the end of each pIR-IR SAR measurement cycle because these samples did not display significant signal recuperation (the 0 Gy regenerative dose pIR-IR signal was consistently <3% of the sensitivity-corrected natural pIR-IR signal for all measured aliquots).