[MW:11816] Ir92 with 32 Curie-What is the safe distance?

Dear All,

In one fabrication yard,IR192(Iridium192) Isotope being used to take radiography of welded joints to ensure it's integrity after visual inspection.NDT crew usually brings radiation source with a strength of 32 Curie(NDT contractor claiming that they are using 32 curie only but I don't know the exact strength.This is due to client pressure otherwise they are ready to bang with higher curies!!).I would like to know what would be the safe distance when IR92 with 32 curie strength operates without collimator.How can I calculate the safe distance from above parameters?I need this calculation urgently due to non availability of completely covered (except roof) concrete bunker or natural sand wall.For NDT crew protection during RT, two pieces of concrete wall provided to cover their body.Moreover, people like skilled/unskilled workers are staying very close(20Mtr to 35 Mtr range) to radiography area and nobody aware of the seriousness of the activity including the world famous client!!!

It will be highly appreciated if someone could provide an excel spread sheet to calculate the safe distance for different source strength.

Thanks in advance



Regards,


Limesh

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