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2 X C 2 Mass Number A Atomic Number Z 14 6
Z = number of protons A = number of nucleons N = A – Z = number of neutrons C 14 6 Also known as Carbon-14 , this element has 6 protons and 8 neutrons.

3 3 time=0 1 half-life 2 half-lives 3 half-lives
t= years 5730x2=11,460yrs 5730x3=17,190yrs m= x1/2= 64 g 64x1/2= 32 g 32x1/2= 16 g Mass of Carbon-14, grams Time, years

4 4 Amount = (Initial Amount) = A0 2no of half-lives 2n
where n is the number of half-lives Eg. How much radioactive material will there be after 30 days if you start with 1000g and the half-life is 6 days? n = 5 A = A0/2n A0 = = 1000/25 = 1000/32 = g No of half-lives = total time/half-life = 30/6 = 5

5 X Y  5 Alpha Decay,  A Z A-4 Z-2 4 2 proton neutron Alpha particle
Daughter nucleus X A Z Y A-4 Z-2 4 2

6 6 proton Neutron Electron Beta Decay,  Beta particle Daughter nucleus X A Z Z+1 -1 1 neutron becomes 1 proton and 1 electron

7 7 proton neutron Gamma Decay,  Gamma ray X* A Z X

8 8

9 9 Normal Material Normal Molecule Affected Molecule Alpha radiation
Gamma radiation Gamma ray still travelling

10 10 Absorbed = energy absorbed Dose mass of body Unit is the Gray, Gy
Each person absorbs 20 J of ionising radiation Mass = 60kg mass = 25kg Absorbed = energy absorbed Dose mass of body Unit is the Gray, Gy AD = En/mass = 20/60 = 0.33 Gy AD = En/mass = 20/25 = 0.8 Gy

11 11 DE = AD x QF Dose Equivalent = absorbed dose x quality factor
Unit is the Sievert, Sv DE = AD x QF Radiation Quality Factor Alpha 20 Neutrons 5 Beta 1 Gamma 1 For example, an absorbed dose of 0.33 Gy has a dose equivalent of: DE = AD x QF = 0.33 x for beta particles = 0.33 Sv DE = AD x QF = 0.33 x 20 for alpha particles = 6.6 Sv

12 Duration of dose equivalent (acute/chronic)
12 Dose equivalent (mSv) Duration of dose equivalent (acute/chronic) Effect 15000 acute and chronic Fatal effects in all cases 10000 Likely immediate fatal illness 2000 Threshold for immediate, fatal radiation sickness 1000 chronic Increased likelihood of later development of cancer acute Threshold for immediate, non-fatal radiation sickness 100 Increasing likelihood of cancer 50 Maximum annual dose for any worker. Lowest dose at which cancers may be caused in adults 20 Average limit per year for workers in the nuclear industry, uranium and mineral sands miners, and medical workers


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