6. (a) Consider one of the possible decays of the tau lepton: (ii) (iii) (iv) T...

 

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6. (a) Consider one of the possible decays of the tau lepton: (ii) (iii) (iv) T + X. Which particle(s) is (are) marked as X? Which interaction drives this decay and why? Name five different conservation laws which apply in this process. How would the products change if it was a T+ instead? What other form of decay does the tauon have (not violating conservation laws)? (c) Consider the following decay: (b) A diagnostic X-ray of a patient's arm delivers an equivalent dose of 2 mSv. If the X-rays energy is 30 keV and the mass of their arm is 2 kg, how many X-ray photons have been absorbed? [4 marks] 23 Pu 232U+ with t/2 = 87.7 yr and Ea = 5.5 MeV. 94 [2 marks] Question 6 continued on next page... Question 6 continued... (i) Estimate the recoil energy of the daughter nucleus. (ii) A Pu-238 source is fitted on a space probe to provide the energy required for the landing on a large asteroid after 4 years. If 10 % of the a-particle energy released in this decay can be converted to electrical power and 200 W of power is needed to perform the landing, estimate what mass of Pu- 238 needs to be mounted on the probe at launch. (iii) What, in general, are the conditions for a secular equilibrium in parent- daughter chain decay? Sketch qualitatively the time-dependence of the parent and daughter activities, starting from a pristine sample of parent nuclei and approaching such equilibrium. (iv) U-234 is also radioactive with a larger half-life. Assume that was not the case and it had a much shorter half-life compared to its parent. In part (ii), how would the required mass of Pu-238 change if you assume at the time of the landing parent-daughter chain decays were in secular equilibrium, and U-234 released an alpha of a similar energy? 6. (a) Consider one of the possible decays of the tau lepton: (ii) (iii) (iv) T + X. Which particle(s) is (are) marked as X? Which interaction drives this decay and why? Name five different conservation laws which apply in this process. How would the products change if it was a T+ instead? What other form of decay does the tauon have (not violating conservation laws)? (c) Consider the following decay: (b) A diagnostic X-ray of a patient's arm delivers an equivalent dose of 2 mSv. If the X-rays energy is 30 keV and the mass of their arm is 2 kg, how many X-ray photons have been absorbed? [4 marks] 23 Pu 232U+ with t/2 = 87.7 yr and Ea = 5.5 MeV. 94 [2 marks] Question 6 continued on next page... Question 6 continued... (i) Estimate the recoil energy of the daughter nucleus. (ii) A Pu-238 source is fitted on a space probe to provide the energy required for the landing on a large asteroid after 4 years. If 10 % of the a-particle energy released in this decay can be converted to electrical power and 200 W of power is needed to perform the landing, estimate what mass of Pu- 238 needs to be mounted on the probe at launch. (iii) What, in general, are the conditions for a secular equilibrium in parent- daughter chain decay? Sketch qualitatively the time-dependence of the parent and daughter activities, starting from a pristine sample of parent nuclei and approaching such equilibrium. (iv) U-234 is also radioactive with a larger half-life. Assume that was not the case and it had a much shorter half-life compared to its parent. In part (ii), how would the required mass of Pu-238 change if you assume at the time of the landing parent-daughter chain decays were in secular equilibrium, and U-234 released an alpha of a similar energy?

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The question image depicts a multipart physics problem focused on particle physics and nuclear physics Part a i The process shown is a lepton decay specifically the decay of a tau lepton into a muon T... View the full answer