Cosmogenic radionuclides

Cosmogenic radionuclides

• The cosmogenic nuclides ¹⁰Be (T_1/2 = 1.30 Myr), ²⁶Al (T_1/2 = 700 kyr) and ³⁶Cl (T_1/2 = 300 kyr) are continuously formed by solar and cosmic radiation in the atmosphere. With their help, natural archives such as ice cores, sediments or water can be dated. If a higher or lower production of the above mentioned nuclides compared to today's rate is detected, this may indicate additional sources of cosmic radiation or changes in the magnetic fields of the earth or our sun in the past. In addition, ¹⁰Be, ²⁶Al and ³⁶Cl can be used to measure the duration of exposure to cosmic rays at the surface of a rock. This so-called surface exposure dating can provide information about processes on the Earth's surface and can be used, e.g. to study glacier movements.

• The newly developed ILIAMS (Ion Laser InterAction Mass Spectrometry) setup at VERA improves the possibility to measure ²⁶Al and ³⁶Cl by laser-assisted isobar separation. By suppressing the isobars ²⁶Mg and ³⁶S by several orders of magnitude, blank values of ²⁶Al/Al = 5×10^–16 and ³⁶Cl/Cl = 8×10^–16 can be achieved at VERA.