Protecting Self from Gamma Source: Find Lead Thickness

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Discussion Overview

The discussion centers around the appropriate thickness of lead shielding required to protect against gamma radiation from a 57Co isotope source used in Mössbauer spectroscopy. Participants explore calculations related to shielding effectiveness, safety protocols, and the adequacy of existing protective measures.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant calculates the required lead thickness using the formula I(x)=I exp(-kx) and suggests approximately 6 mm based on their parameters.
  • Another participant questions the need for shielding and the controlled environment in which the gamma source is used.
  • A participant clarifies that the source is a 57Co isotope used for Mössbauer spectroscopy and expresses uncertainty about the shielding requirements.
  • Concerns are raised about the adequacy of existing shielding, with one participant noting that other labs use around 5 cm of lead.
  • Another participant emphasizes that gamma sources should typically be in shielded containers and suggests consulting health physics personnel for additional safety measures.
  • One participant mentions that TÜV personnel assessed the shielding based on strength and exposure dose rate, asserting that they feel safe with the current setup.

Areas of Agreement / Disagreement

Participants express varying levels of concern regarding the adequacy of shielding, with some suggesting that additional measures may be necessary while others assert that current protocols are sufficient. No consensus is reached on the exact thickness required or the safety of the current setup.

Contextual Notes

Participants reference specific parameters such as the linear attenuation coefficient and exposure dose rates, but there is no resolution on the adequacy of the proposed lead thickness or the safety protocols in place.

Who May Find This Useful

Individuals working with radioactive sources, health physics professionals, and those involved in experimental physics or radiation safety may find this discussion relevant.

Rajini
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Hello all,
i need one suggestion for shielding of a gamma source.
I have a gamma source with initial activity of 50 mCi=1.85X10^9Bq.
What thickness of lead needed to protect myself!
I used the formula I(x)=I exp(-kx). I=50mCi; k=37.6 cm^2/g (linear attenuation for 122 keV) and x the thickness needed (i took I(x)=1). By the above formula i get ~6mm. Is that okay..
if i am wrong pls. correct me!
2. Is there any good website to get k (linear attenuation) values?

thanks
 
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Um - what radioisotope?

I would presume one has this material in a controlled environment in a laboratory or licensed facility?! And why would one need to be asking about shielding?
 
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57Co-isotope (details are there on www; but about shielding?) for mössbauer spectroscopy! (i am working with it, but i am not sure about shielding)
thanks
 
Are you doing the mössbauer spectroscopy in a laboratory? If so, I would expect that someone from the health physics department would have set up the shielding. Also, such sources would come in a shielded (shipping/storage) container, such that at the surface, the dosage should be about background, or no more than an order of magnitude above background.
 
Hello..
Yes...but here some ppl. from (tüv)+health guys checked..they said its okay..but i am worried..because in other labs i noticed they use around 5 cm. That why i asked here...
actually are not big mössbauer gurus..so ppl. pay less attention..
thanks
..i already mounted the source..i used a lead glass..equivalent to 3 mm lead..(however my hands are exposed..for some seconds)
i think 6 mm should be fine..any we don't stay there for more than a minute per day..sometimes..per week
 
Last edited:
Normally a gamma source would be in a shielded container. In Mössbauer spectroscopy, the source should be shielded and collimated.

TÜV personnel are normally very conscientious. If you have concerns, then talk to the supervisor about your concerns and perhaps request additional shielding. I presume one has a dosimeter badge since one is working around radioactive sources. If not - one should immediately get one and become registered with the radiation protection group at the lab.
 
Oh yes..we did that!...(one more time)..
They actually did based on strength, lead thickness and also on exposion dose rate.
and i am completely safe!
thanks
 

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