Difference between revisions of "Problem set 5"
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= Particles and Nuclear Reactions<br> = | = Particles and Nuclear Reactions<br> = | ||
| − | ====== | + | ====== Return to [[Problem Solving Sets]] ====== |
<br> | <br> | ||
| − | + | '''1:'''<br> | |
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| − | ''1 | ||
#What it is a thermal neutron? | #What it is a thermal neutron? | ||
#Neutrons are produced with high energy. How do you reduce their energy without losing them.<br> | #Neutrons are produced with high energy. How do you reduce their energy without losing them.<br> | ||
| − | #What is a neutron moderator and what is a neutron absorbent | + | #What is a neutron moderator and what is a neutron absorbent? Give two examples of both. |
| − | #Neutrons is often detected by gas- detektors filled with <sup>3</sup>He. Why <sup>3</sup>He and not <sup>4</sup>He | + | #Neutrons is often detected by gas- detektors filled with <sup>3</sup>He. Why is <sup>3</sup>He used and not <sup>4</sup>He? |
| − | #Neutral radiation is detected by making charged particles. Which reaction happens when tubes filled <sup>3</sup>He is used as neutron detectors | + | #Neutral radiation is detected by making charged particles. Which reaction happens when tubes filled <sup>3</sup>He is used as neutron detectors? |
| − | #What is the Q-value of the reaction in | + | #What is the Q-value of the reaction in 5)? Is the reaction endothermic or exothermic? |
| − | #Two charged particles are created in the reactions, which particles | + | #Two charged particles are created in the reactions, which particles? |
| − | #What energy does each of the to particles receive when a thermal neutron reacts | + | #What energy does each of the to particles receive when a thermal neutron reacts? |
<br> | <br> | ||
| − | '' | + | '''''2'':''' One of the quite few nuclear reactions that happened during the birth of the universe (“big bang”) is: n + p → d + γ.<br> |
#Calculate the Q-value of the reaction. | #Calculate the Q-value of the reaction. | ||
#What is the energy of the gamma ray? | #What is the energy of the gamma ray? | ||
| − | #What is the energy of the deuterium | + | #What is the energy of the deuterium? Assume a thermal neutron. |
<br> | <br> | ||
| − | '''3:''' The most important | + | '''3:''' The most important process for fusion in the sun is, in total 4p → α + 2e<sup>+</sup>+ 2 <span class="texhtml">μ</span>. Calculate the Q-values and determine the end products for these reactions: <br> |
| − | #<sup>40</sup>Ca(alpha,gamma) | + | #<sup>40</sup>Ca(alpha,gamma) |
| − | #<sup>52</sup>Cr(aplha,gamma) | + | #<sup>52</sup>Cr(aplha,gamma) |
| − | #<sup>56</sup>Fe(alpha,gamma) | + | #<sup>56</sup>Fe(alpha,gamma) |
| − | # | + | #<sup>58</sup>Ni(alpha,gamma) |
<br> | <br> | ||
| − | '''4:''' Use | + | '''4:''' Use Nuclear Wallet Cards to do the following calculations: <br> |
| − | #The maximum kinetic energy of the positron/electron for | + | #The maximum kinetic energy of the positron/electron for <sup>14</sup>C. |
| − | #The maximum kinetic energy of the positron/electron for the neutron | + | #The maximum kinetic energy of the positron/electron for the neutron. |
| − | #The maximum kinetic energy of the positron/electron for | + | #The maximum kinetic energy of the positron/electron for <sup>18</sup>F. |
| − | #The maximum kinetic energy of the positron/electron for | + | #The maximum kinetic energy of the positron/electron for <sup>64</sup>Cu ( both disintegrations). |
#Nuclei that decays by both beta minus and beta plus are of a special type. Why is this? | #Nuclei that decays by both beta minus and beta plus are of a special type. Why is this? | ||
| − | #Calculate the mass of <sup>228</sup>Ra from information from the | + | #Calculate the mass of <sup>228</sup>Ra from information from the Chart of the Nuclides. |
<br> | <br> | ||
| − | '''5:''' In a breeder-reactor a new fissile atom is created from each atom that | + | '''5:''' In a breeder-reactor a new fissile atom is created from each atom that fissions. Breeder-reactors can be made from thorium and uranium as starting material.<br> |
#Write down the nuclear reactions which gives new fissile atoms in a uranium-breeder reactor and in a thorium-breeder reactor. | #Write down the nuclear reactions which gives new fissile atoms in a uranium-breeder reactor and in a thorium-breeder reactor. | ||
| − | #Calculate the work (in watt) that is generated when one kg | + | #Calculate the work (in watt) that is generated when one kg of uranium metal is irradiated in a neutron flux of 10<sup>14</sup> neutrons/(cm<sup>2</sup>s). |
<br> | <br> | ||
| − | '''6:''' Borium | + | '''6:''' Borium absorbs thermal neutrons well.<br> |
#Write down the nuclear reaction that happens. | #Write down the nuclear reaction that happens. | ||
| − | #Calculate the Q-value | + | #Calculate the Q-value for the reaction. |
| − | #A | + | #A flux of 10<sup>14</sup> neutrons/(cm<sup>2</sup>s) striking an area of 100 cm<sup>2</sup> is completely stopped by a wall of borium. Calculate the work (in watt). |
<br> | <br> | ||
| − | '''7:''' The radionuclide <sup>89</sup>Zr has a half-life of 78 hours and is often generated in hospitals by a cyclotron. It is generated by the nuclear reaction <sup>89</sup>Y(p,n)<sup>89</sup>Zr. The cross section | + | '''7:''' The radionuclide <sup>89</sup>Zr has a half-life of 78 hours and is often generated in hospitals by a cyclotron. It is generated by the nuclear reaction <sup>89</sup>Y(p,n)<sup>89</sup>Zr. The cross section for this reaction is 0.8 b with 12MeV protons.<br> |
| + | |||
| + | #Calculate the Q-value for this reaction. | ||
| + | #Find a production speed that is able to generate a sample of 1 Gbq of <sup>89</sup>Zr with 6 hours of irradiation time. | ||
| + | #In this case the target material is cheap and there is no need to regenerate it. Why is it so? <br> | ||
| − | + | [[Category:Unsolved Problems]]<br> [[Category:Bachelor]] | |
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Latest revision as of 10:02, 9 July 2012
Particles and Nuclear Reactions
Return to Problem Solving Sets
1:
- What it is a thermal neutron?
- Neutrons are produced with high energy. How do you reduce their energy without losing them.
- What is a neutron moderator and what is a neutron absorbent? Give two examples of both.
- Neutrons is often detected by gas- detektors filled with 3He. Why is 3He used and not 4He?
- Neutral radiation is detected by making charged particles. Which reaction happens when tubes filled 3He is used as neutron detectors?
- What is the Q-value of the reaction in 5)? Is the reaction endothermic or exothermic?
- Two charged particles are created in the reactions, which particles?
- What energy does each of the to particles receive when a thermal neutron reacts?
2: One of the quite few nuclear reactions that happened during the birth of the universe (“big bang”) is: n + p → d + γ.
- Calculate the Q-value of the reaction.
- What is the energy of the gamma ray?
- What is the energy of the deuterium? Assume a thermal neutron.
3: The most important process for fusion in the sun is, in total 4p → α + 2e++ 2 μ. Calculate the Q-values and determine the end products for these reactions:
- 40Ca(alpha,gamma)
- 52Cr(aplha,gamma)
- 56Fe(alpha,gamma)
- 58Ni(alpha,gamma)
4: Use Nuclear Wallet Cards to do the following calculations:
- The maximum kinetic energy of the positron/electron for 14C.
- The maximum kinetic energy of the positron/electron for the neutron.
- The maximum kinetic energy of the positron/electron for 18F.
- The maximum kinetic energy of the positron/electron for 64Cu ( both disintegrations).
- Nuclei that decays by both beta minus and beta plus are of a special type. Why is this?
- Calculate the mass of 228Ra from information from the Chart of the Nuclides.
5: In a breeder-reactor a new fissile atom is created from each atom that fissions. Breeder-reactors can be made from thorium and uranium as starting material.
- Write down the nuclear reactions which gives new fissile atoms in a uranium-breeder reactor and in a thorium-breeder reactor.
- Calculate the work (in watt) that is generated when one kg of uranium metal is irradiated in a neutron flux of 1014 neutrons/(cm2s).
6: Borium absorbs thermal neutrons well.
- Write down the nuclear reaction that happens.
- Calculate the Q-value for the reaction.
- A flux of 1014 neutrons/(cm2s) striking an area of 100 cm2 is completely stopped by a wall of borium. Calculate the work (in watt).
7: The radionuclide 89Zr has a half-life of 78 hours and is often generated in hospitals by a cyclotron. It is generated by the nuclear reaction 89Y(p,n)89Zr. The cross section for this reaction is 0.8 b with 12MeV protons.
- Calculate the Q-value for this reaction.
- Find a production speed that is able to generate a sample of 1 Gbq of 89Zr with 6 hours of irradiation time.
- In this case the target material is cheap and there is no need to regenerate it. Why is it so?
