Modulation of Cosmogenic Tritium in Meteoric Precipitation by the 11-year Cycle of Solar Magnetic Field Activity.

The relationship between the atmospheric concentration of cosmogenic isotopes, the change of solar activity and hence secondary neutron flux has already been proven. The temporal atmospheric variation of the most studied cosmogenic isotopes shows a significant anti-correlation with solar cycles. However, since artificial tritium input to the atmosphere due to nuclear-weapon tests masked the expected variations of tritium production rate by three orders of magnitude, the natural variation of tritium in meteoric precipitation has not previously been detected. For the first time, we provide clear evidence of the positive correlation between the tritium concentration of meteoric precipitation and neutron flux modulated by solar magnetic activity. We found trends in tritium time series for numerous locations worldwide which are similar to the variation of secondary neutron flux and sun spot numbers. This variability appears to have similar periodicities to that of solar cycle. Frequency analysis, cross correlation analysis, continuous and cross wavelet analysis provide mathematical evidence that the correlation between solar cycle and meteoric tritium does exist. Our results demonstrate that the response of tritium variation in precipitation to the solar cycle can be used to help us understand its role in the water cycle.

Homogeneity assessment for grass samples used for organically bound tritium proficiency test.

The paper presents homogeneity check for dried grass batch to be used in an inter-comparison exercise. When carrying out an inter-comparison exercise, the organizer must guarantee that the unsatisfactory result will not be imputed to the sample and sample's changeability. Therefore, in an inter-comparison exercise must carry on the homogeneity testing. In our study, the homogeneity was checked for two parameters, the hydrogen percentage (%H) and the organically bound tritium (OBT) activity concentration. Ten subsamples of 50g from bulk material were chosen using a stratified random selection. Two replicates from each package were analyzed for hydrogen content and OBT analysis. The homogeneity parameters were evaluated according to ISO 13528:2015. The two checked properties confirm that the batch of dried grass is sufficiently homogenous.

Tritium time series in precipitation of Rm. Valcea, Romania.

Following tritium concentration records in precipitation for the period 1999-2013 and tritium concentration behaviour during this period for the Ramnicu Valcea (Rm. Valcea) location, the tritium level of individual precipitations of the late spring and summer for the 2009-2013 period was investigated. Despite good correlation between monthly mean tritium concentrations and monthly mean precipitations over the 15-year period of observations (Pearson coefficient 0.87), the individual precipitations had no linear correlation between the tritium concentration and the amount of precipitation.