Portable Device for express monitoring of
food contaminated with radioactive isotopes Cs-137, etc.
Our Portable Device provides an integrated radio-ecological
monitoring of food products in 5-8 minutes. The weight of the Portable Device
is about 30 kg. The equipment and certified techniques and procedures allow
the following applications. In the stationary laboratory:
- to identify the specific (volume) activity of
radionuclides in liquid, granular and solid samples;
- to identify the radionuclide
composition and activity of
gamma-emitting nuclides in food, soil samples, building materials,
timber and other environmental objects;
- to store the results on a computer;
- to print the measurement results.
Radiometric and spectrometric channels make use of
scintillation detectors on the basis of CsI(Tl) crystals of size 30x70 mm
(in the mobile unit) and 40x45 mm (in the stationary unit).
The mobile gamma detector unit has a hermetic cylindrical
casing with a convenient handle for long use in field conditions.
The stationary gamma detector unit has a 40-mm-thick lead shield with
a 0.5 l Marinelli vessel, detector, power source, photoelectronic multiplier
and preamplifier. Under laboratory conditions, the stationary gamma-detector unit
can be used to measure the volume activity of samples. In this case the station
is powered from the stationary power unit, which includes a battery charger device
in addition to the power source.
All units are designed to work in field conditions and
are hermetically sealed. In stand-alone mode, the station is powered from sealed
lead-acid battery with a voltage of 12 volts, which can be charged directly from a car.
For instance, using this device we measured 1-kg packages
filled with rice, which were bought in food shops in Japan in April 2012.
Three different packeges showed the following contamination with Cs-137:
46, 250 and 639 Bq/kg. Besides, other contaminates also were detected
(in particular, Cs-134, K-40, Eu-154).
Although, in time just after the Chornobyl disaster of
1986 the Ukrainian standard was no more than 25 Bq/kg (for meat) and
less values for vegetables and grain products.
At the moment packges with rice bought in Kyiv, Ukraine, produced in Pakistan, Egypt,
India and Ukraine show the radioactivity at the level less than 1 Bq/kg.