Cesium contaminated soil

[lodovico]

Hi everybody,
for the "cesium lovers" I have done some measurement of a contaminated soil from belarus :

SoilCesium3.png

Here are the complete results : http://physicsopenlab.org/2017/06/22/ce ... ated-soil/
Tell me what do you think about my countings.
Thank you
Lodovico

[luuk]

Hi Lodevico,

Thanks for the spectrum the Cs peak is good to see but I think you need some lead shielding to get the peaks a little better above the background.

It is interesting I also got a sample from Belarus from Alberto Marturini I suppose it is from the same batch and did some test with it.
What I found is that the Cs-137 contamination is still strong in the soil sample, 26 years after the Tsjernobyl accident.
I measured one hour and got 5.2cps on a 3x3"NaI(Tl) the sample is 9 Gram so that gives 0.6c/gram.
I took the total counts from 1 KeV to 2 MeV.
But the detector was not a well detector so the efficiency is <50% so the outcome have to be multiplied by two so 1.2c/gram gives 1200c/Kg.
As far as I could see that is no other contamination in the sample.
The spectra are taken in a large professional lead castle(>1800 Kg) so you cannot compare it with your spectrum.
Luuk
See attached file

[lodovico]

Thanks Luuk for your data.
yes the source of the sample is the same (Alberto Marturini) ! Here below there is another spectrum (with background superimposed) and the Cesium peak is more evident, the CPS are little less then yours, 2CPS more or less. This measure has been done with the sample (5.6g) at contact to the detector 63x63mm.
The first measure has been done with sample and detector at a a distance of 5cm in order to have the same setup used to calibrate the detector with the cesium sample source.

Lodovico

ThereminoMCA_2017_06_29_22_55_28.png

[luuk]

Hi Lodovico,

Yes, this new spectrum looks better, main problem is the shielding to get a nice clear peak.
The spectrum I made is done at my work so that is not a fair comparison to home made spectra, but it was just to show
that the contamination is still strong after so many years.
If you are interested I still have some soil from Fukuhima that is much"hotter and contains Cs-134 as well, if interested send me a offlist email.
Luuk

[lodovico]

Hi,
I use a home made lead shield (with lead shots), it works ok but I understand that a professional lead shield makes the difference for low activity samples. I sent you a private message for the japanese soil sample !
Thank you
Lodovico