Difference between revisions of "Solutions 7"
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#<math>\lambda = 7.3466 \cdot ^{-10}s^{-1}</math><br><math>D=\lambda \cdot N \rightarrow N=\frac{D}{\lambda}=\frac{6000 \, Bq}{\lambda}=8.17\cdot 10^{12}</math><br> which is 1.36<math>\cdot</math>10<sub>-11</sub> mol of <sub>137</sub>Cs | #<math>\lambda = 7.3466 \cdot ^{-10}s^{-1}</math><br><math>D=\lambda \cdot N \rightarrow N=\frac{D}{\lambda}=\frac{6000 \, Bq}{\lambda}=8.17\cdot 10^{12}</math><br> which is 1.36<math>\cdot</math>10<sub>-11</sub> mol of <sub>137</sub>Cs | ||
− | # Calculate the initial dose rate from the renderer meat:<br><math>6000\, Bq \cdot 200 keV\cdot 1.6\cdot 10^{-16} \frac{J}{kev}=1.92\cdot 10^{-10}\frac{J}{s}</math><br> for a person of 70 kg this gives a dose of 2.74<math>\cdot</math>10<sup>-12</sup>Gy/s.<br> Then calculate the real half-life<br><math>T_{rel}=\frac{T_{B}\cdot T_{P}}{T_{B}+T{P}}\rightarrow \frac{0.302\cdot 30}{0.302+30}=108.9\, d</math><br>Then the total dose will be: <br><math>D_{tot}=\int^{t=\infty}_{t=0}D_{0}\cdot e^{-\lambda t}dt=-\frac{D_{0}}{\lambda}\left[e^{-\lambda t}\right]^{t=\infty}_{t=0}=\frac{D_{0}}{\lambda}(0-1)</math><br><math>=\frac{2.74\cdot 10^{-12}}{7.367\cdot 10^{-8}}=0. | + | # Calculate the initial dose rate from the renderer meat:<br><math>6000\, Bq \cdot 200 keV\cdot 1.6\cdot 10^{-16} \frac{J}{kev}=1.92\cdot 10^{-10}\frac{J}{s}</math><br> for a person of 70 kg this gives a dose of 2.74<math>\cdot</math>10<sup>-12</sup>Gy/s.<br> Then calculate the real half-life<br><math>T_{rel}=\frac{T_{B}\cdot T_{P}}{T_{B}+T{P}}\rightarrow \frac{0.302\cdot 30}{0.302+30}=108.9\, d</math><br>Then the total dose will be: <br><math>D_{tot}=\int^{t=\infty}_{t=0}D_{0}\cdot e^{-\lambda t}dt=-\frac{D_{0}}{\lambda}\left[e^{-\lambda t}\right]^{t=\infty}_{t=0}=\frac{D_{0}}{\lambda}(0-1)</math><br><math>=\frac{2.74\cdot 10^{-12}}{7.367\cdot 10^{-8}}=0.580\, mGy/year</math> |
Revision as of 14:38, 22 June 2012
This solution set contains a large number of errors, and is under revision. It will be updated as soon as possible.
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These exercises it might be usfull to have wallet cards they can for instance be found at Nudat 2
1:
- It is in total 3.58 mol = 2.1562
1024 atoms of potassium in a average human where 12% that is 2.5876 1020 is 40K - First calculate the dose per second:
Then calculate it to joule per second:
which gives:
As the dose can be assumed to be constant trough a human life for each year we will recive a dose of:
2:
which is 1.36 10-11 mol of 137Cs- Calculate the initial dose rate from the renderer meat:
for a person of 70 kg this gives a dose of 2.74 10-12Gy/s.
Then calculate the real half-life
Then the total dose will be: