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Does the amount of radiation (cpm) increase or decrease as thickness of the shielding...

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treysongzlove... | Student, College Freshman | eNoter

Posted December 2, 2012 at 1:48 PM via web

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Does the amount of radiation (cpm) increase or decrease as thickness of the shielding increases while the distance between the source and the stays the same?

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ncchemist | eNotes Employee

Posted December 2, 2012 at 7:18 PM (Answer #1)

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We are asked if the shield thickness makes a difference in the amount of radiation passing through if the distance is kept the same.  The answer is yes.  A thicker shielding has more mass and will therefore block more of the radiation.  Alpha and beta types of radiation emit actual particles.  The shielding actually deflects these particles and prevents them from travelling forward.  Once you have reached a certain thickness, all of the particles are blocked and any extra shielding really doesn't do anything more.  X-rays and gamma radiation, however, are photon base radiation and can therefore penetrate much deeper since there is no particle to block.  Shielding thickness makes a huge difference here.  More shielding provides more atoms to absorb this radiation and prevent it from passing through.

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