Exercises+with+Particles+and+Nuclear+Reactions

 
 * 1: **
 * 1) What it is a thermal neutron?
 * 2) Neutrons are produced with high energy. How do you reduce their energy without losing them?
 * 3) What is a neutron moderator and what is a neutron absorbent? Give two examples of both.
 * 4) Neutrons are often detected by gas- detectors filled with 3 He. Why is 3 He used and not 4 He?
 * 5) Neutral radiation is detected by making charged particles. Which reaction happens when tubes filled 3 He is used as neutron detectors?
 * 6) What is the Q-value of the reaction in 5)? Is the reaction endothermic or exothermic?
 * 7) Two charged particles are created in the reactions, which particles?
 * 8) What energy does each of the two particles receive when a thermal neutron reacts?


 * //2 //****<span style="font-family: 'Times New Roman','serif'; font-size: 16px;">: **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> One of the quite few nuclear reactions that happened during the birth of the universe (“big bang”) is: n + p → d + γ.
 * 1) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Calculate the Q-value of the reaction.
 * 2) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">What is the energy of the gamma ray?
 * 3) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">What is the energy of the deuterium? Assume a thermal neutron.


 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">3: **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> The most important process for fusion in the sun is, in total 4p → α + 2e + <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">+ 2 μ. Calculate the Q-values and determine the end products for these reactions:
 * 1) 40 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Ca(alpha,gamma)
 * 2) 52 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Cr(aplha,gamma)
 * 3) 56 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Fe(alpha,gamma)
 * 4) 58 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Ni(alpha,gamma)


 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">4: **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> Use Nuclear Wallet Cards to do the following calculations:
 * 1) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">The maximum kinetic energy of the positron/electron for 14 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">C.
 * 2) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">The maximum kinetic energy of the positron/electron for the neutron.
 * 3) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">The maximum kinetic energy of the positron/electron for 18 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">F.
 * 4) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">The maximum kinetic energy of the positron/electron for 64 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Cu (both disintegrations).
 * 5) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Nuclei that decays by both beta minus and beta plus are of a special type. Why is this?
 * 6) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Calculate the mass of 228Ra from information from the Chart of the Nuclides.


 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">5: **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> In a breeder-reactor a new fissile atom is created from each atom that fission. Breeder-reactors can be made from thorium and uranium as starting material.
 * 1) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Write down the nuclear reactions which give new fissile atoms in a uranium-breeder reactor and in a thorium-breeder reactor.
 * 2) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Calculate the work (in watt) that is generated when one kg of uranium metal is irradiated in a neutron flux of 10 14 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> neutrons/(cm2s).


 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">6: **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> Borium has a high cross-section to absorb thermal neutrons.
 * 1) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Write down the nuclear reaction that happens.
 * 2) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Calculate the Q-value for the reaction.
 * 3) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">A flux of 10 14 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> neutrons/(cm 2 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">s) striking an area of 100 cm 2 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> is completely stopped by a wall of borium. Calculate the work (in watt).


 * <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">7: **<span style="font-family: 'Times New Roman','serif'; font-size: 16px;"> The radionuclide 89 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Zr has a half-life of 78 hours and is often generated in hospitals by a cyclotron. It is generated by the nuclear reaction 89 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Y(p,n) 89 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Zr. The cross section for this reaction is 0.8 b with 12 MeV protons.
 * 1) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Calculate the Q-value for this reaction.
 * 2) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Find a production speed that is able to generate a sample of 1 Gbq of 89 <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">Zr with 6 hours of irradiation time.
 * 3) <span style="font-family: 'Times New Roman','serif'; font-size: 16px;">In this case the target material is cheap and there is no need to regenerate it. Why is it so?

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