Traces of Radioactive I-131 in Rain Water and Milk Samples in Romania

Measurements of I-131 (T1/2 = 8.04 days) have been performed in IFIN-HH's underground laboratory situated in Unirea salt mine from Slanic-Prahova, Romania. The rain water samples were collected in March 27th in Brasov and in March 27th, 29th and April 2nd in Slanic. Also sheep milk was collected in Slanic area and subsequently measured. The samples were measured in the IFIN-HH's underground laboratory in ultra-low radiation background, using a high resolution gamma-ray spectrometer equipped with a GeHP detector having a FWHM = 1.80 keV at 1332.48 keV at the second Co-60 gamma-ray, and a relative efficiency of 22.8%. The results show a specific activity of I-131 from 0.17 to 0.87 Bq/dm^3. In the sheep milk from Slanic area the specific activity of I-131 was about 6 Bq/dm^

A mobile detector for measurements of the atmospheric muon flux in underground sites

Muons comprise an important contribution of the natural radiation dose in air (approx. 30 nSv/h of a total dose rate of 65-130 nSv/h), as well as in underground sites even when the flux and relative contribution are significantly reduced. The flux of the muons observed in underground can be used as an estimator for the depth in mwe (meter water equivalent) of the underground site. The water equivalent depth is an important information to devise physics experiments feasible for a specific site. A mobile detector for performing measurements of the muon's flux was developed in IFIN-HH, Bucharest. Consisting of 2 scintillator plates (approx. 0.9 m2) which measure in coincidence, the detector is installed on a van which facilitates measurements at different locations at surface or underground. The detector was used to determine muon fluxes at different sites in Romania. In particular, data were taken and the values of meter water equivalents were assessed for several locations from the salt mine from Slanic Prahova, Romania. The measurements have been performed in 2 different galleries of the Slanic mine at different depths. In order to test the stability of the method, also measure- ments of the muon flux at surface at different elevations were performed. The results were compared with predictions of Monte-Carlo simulations using the CORSIKA and MUSIC codes