Climate and Environmental Physics (CEP)

Noble Gas Radionuclides

Our institute has sophisticated analytical facilities and experience for measurement and interpretation of environmental tracer data, in particular of the radioactive noble gases ⁸⁵Kr and ³⁹Ar which allow the determination of groundwater residence times from 10-1000 years.
We can perform complete studies from sampling, activity measurements and interpretation.

Environmental Traces in Groundwater Hydrology

Environmental tracers provide insight on groundwater flow and transport dynamics on a regional scale in aquifers because of their inherent spatial and temporal averaging properties.

Noble gases are ideal tracers of water movement because they are chemically inert and undergo no chemical reactions that could affect their interpretation (e.g. in terms of groundwater residence times)

Applications are:

Estimation of groundwater residence times
Resolution of complete age structures and mixing ratios of different water components
Quantification of groundwater recharge to regional groundwater systems
Determination of the origin of groundwater
Constrain parameters of the fracture network of a fractured aquifer

Dating range of isotope methods. ³⁹Ar with a half-life of 269 years closes the gap between the young residence time indicators ³H/³He, ⁸⁵Kr and CFCs and the ¹⁴C method. CEP provides experience for a comprehensive tracer and residence time spectrum (³⁹Ar worldwide exclusively in Bern)

Analytical procedure from water degassing in the field, over noble gas separation and activity measurement in the laboratory in Bern

Sampling for 85Kr, 39Ar and 14C — Sampling for ⁸⁵Kr, ³⁹Ar and ¹⁴C

Proportional counting in underground laboratory at University of Bern