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textbook:nrctextbook:chapter18
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textbook:nrctextbook:chapter18 [2025-05-05 12:28] Merja Herzig |
textbook:nrctextbook:chapter18 [2025-05-05 13:25] (current) Merja Herzig |
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| - | 4. How many impulses should be recorded from a radioactive sample to observe a [[textbook: | + | 4. How many impulses should be recorded from a radioactive sample to observe a of the number of impulses lower than 0.5%? |
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| - | 5. The [[textbook: | + | 5. The [[textbook: |
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| - | 6. Calculate the uncertainty of the human body activity determined in exercise 5. Use uncertainty propagation law. You do not need to take into account uncertainties of intensity, counting efficiency and counting time. Express the result as the activity with its uncertainty. | + | 6. Calculate the [[textbook: |
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| 1. A sample with an activity of 55.0 kBq was measured with a GM counter and number of | 1. A sample with an activity of 55.0 kBq was measured with a GM counter and number of | ||
| - | observed net counts was 280 000. Another sample with an activity of 55.0 Bq, obtained by diluting the first sample by a factor of 1000, was then measured with the same GM counter in identical conditions. In this case the number of pulses was 350. Calculate the counting efficiency of the counting system and dead-time of the GM detector. | + | observed |
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| - | 2. Calculate the uncertainties of counting efficiency and dead-time observed in exercise 1, using uncertainty propagation law, for a case where the uncertainty of both samples was 2%. Express the results as the counting efficiency and the dead-time with their uncertainties. | + | 2. Calculate the uncertainties of [[textbook: |
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| - | 3. An unknown radionuclide was measured with a GM counter having a dead-time of 32 µs. The observed net count rate was 280 000 imp/min on March 15< | + | 3. An unknown radionuclide was measured with a GM counter having a [[textbook: |
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| ==== 18.3.1. Exercises ==== | ==== 18.3.1. Exercises ==== | ||
| - | 1. Molybdenum was irradiated with thermal neutrons to produce radioactive < | + | 1. Molybdenum was irradiated with [[textbook: |
| Use equation: | Use equation: | ||
| $$A_2 = \frac{\lambda_2 \lambda_1}{\lambda_2 - \lambda_1} N_1^0 \left( 2^{-\frac{t}{t_1}} - 2^{-\frac{t}{t_2}} \right)$$ | $$A_2 = \frac{\lambda_2 \lambda_1}{\lambda_2 - \lambda_1} N_1^0 \left( 2^{-\frac{t}{t_1}} - 2^{-\frac{t}{t_2}} \right)$$ | ||
| - | 2. A fish sample of 2.0 g weight was irradiated in a reactor for 2.0 hours with a neutron flux of 5.0×10< | + | 2. A fish sample of 2.0 g weight was irradiated in a [[textbook: |
| Use equation: | Use equation: | ||
| $$A_\tau = \sigma \phi N_1 \left( 1 - 1^{-\frac{t_S}{T}} \right) 2^{-\frac{t}{T}}$$ | $$A_\tau = \sigma \phi N_1 \left( 1 - 1^{-\frac{t_S}{T}} \right) 2^{-\frac{t}{T}}$$ | ||
| - | 3. To determine the neutron flux of a reactor 10 mg of copper was irradiated for 4.0 hours. 25 hours and 36 minutes after the irradiation was terminated the < | + | 3. To determine the neutron flux of a [[textbook: |
| - | 4. < | + | 4. < |
| period up to 100 days. When the nuclide activities are identical? When the < | period up to 100 days. When the nuclide activities are identical? When the < | ||
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| ==== 18.4.1. Exercises ==== | ==== 18.4.1. Exercises ==== | ||
| - | 1. A medical doctor determines the blood volume of a patient by injecting 0.15 ml of < | + | 1. A medical doctor determines the blood volume of a patient by injecting 0.15 ml of < |
| - | patient. | + | |
| - | 2. Calculate the uncertainty of the blood volume determined in exercise 1. The uncertainty of the injection volume was 0.01 ml and the relative uncertainties of the initial and final < | + | 2. Calculate the [[textbook: |
| - | 3. < | + | 3. < |
| ==== 18.4.2. Solutions ==== | ==== 18.4.2. Solutions ==== | ||
textbook/nrctextbook/chapter18.1746440917.txt.gz · Last modified: 2025-05-05 12:28 by Merja Herzig