442
8 Nuclear Physics – II
8.59 The Q- value of the reaction
16 O(d, n)
17 F is −1.631 MeV, while that of the
reaction
16 O(d, p)
17 O is +1.918 MeV. Which is the unstable member of the
pair
17 O−
17
F, and what is the maximum energy of β-particles it emits? (n−
1 H
mass difference is 0.782 MeV)
[University of Manchester 1958]
8.60 An aluminum target is bombarded by α-particles of energy 7.68 MeV, and the
resultant proton groups at 90
◦ were found to possess energies 8.63, 6.41, 5.15
and 3.98 meV. Draw an energy level diagram of the residual nucleus, using the
above information.
[Osmania University 1963]
8.61 If the Q-value for the
3 H( p, n)
3 He reaction is −0.7637 MeV and tritium (
3 H)
emits negative β-particles of end point energy 18.5 KeV, calculate the difference in mass between the neutron and the hydrogen atom.
[Andhra University]
8.62 The reaction
3 H(d, n)
4 He has Q value of 17.6 MeV. What is the range of neutron energies that may be obtained from this reaction for an incident deuteron
beam of 300 KeV?
[Osmania University 1970]
8.63 A target of
181 Ta is bombarded with 5 MeV protons to form
182 W in an excited
state. Calculate the energy of the excited state (ignore the coulomb barrier and
assume the target nuclei at rest). If
182 W in the same excited state were produced by bombarding a hydrogen target with energetic Ta nuclei, what energy
would be needed? The atomic masses in amu are:
1 H 1 = 1.007825;
181
73 Ta =
180.948007;
182
74 W = 181.948301
[University of Durham 1963]
8.64 In the reaction
48 Ca +
16 O →
49 Sc +
15 N, the Q-value is −7.83 MeV. What is
the minimum kinetic energy of bombarding
16 O ions to initiate the reaction?
At this energy, estimate the orbital angular momentum in units of of the ions
for grazing collision. Take R = 1.1 A
1/3 fm.
8.2.11 Cross-sections
8.65 Calculate the thickness of Indium foil which will absorb 1% of neutrons incident at the resonance energy for Indium (1.44 eV) where σ = 28, 000 barns.
At. Wt of Indium = 114.7 amu, density of Indium = 7.3 g/cm
3 .
[Andhra University]
8.66
60 Co is produced from natural cobalt in a reactor with a thermal neutron flux
density of 5 × 10
12 n cm
−2 s
−1 . Determine the maximum specific activity.
Given σ act = 20 b.
8 Nuclear Physics – II
8.59 The Q- value of the reaction
16 O(d, n)
17 F is −1.631 MeV, while that of the
reaction
16 O(d, p)
17 O is +1.918 MeV. Which is the unstable member of the
pair
17 O−
17
F, and what is the maximum energy of β-particles it emits? (n−
1 H
mass difference is 0.782 MeV)
[University of Manchester 1958]
8.60 An aluminum target is bombarded by α-particles of energy 7.68 MeV, and the
resultant proton groups at 90
◦ were found to possess energies 8.63, 6.41, 5.15
and 3.98 meV. Draw an energy level diagram of the residual nucleus, using the
above information.
[Osmania University 1963]
8.61 If the Q-value for the
3 H( p, n)
3 He reaction is −0.7637 MeV and tritium (
3 H)
emits negative β-particles of end point energy 18.5 KeV, calculate the difference in mass between the neutron and the hydrogen atom.
[Andhra University]
8.62 The reaction
3 H(d, n)
4 He has Q value of 17.6 MeV. What is the range of neutron energies that may be obtained from this reaction for an incident deuteron
beam of 300 KeV?
[Osmania University 1970]
8.63 A target of
181 Ta is bombarded with 5 MeV protons to form
182 W in an excited
state. Calculate the energy of the excited state (ignore the coulomb barrier and
assume the target nuclei at rest). If
182 W in the same excited state were produced by bombarding a hydrogen target with energetic Ta nuclei, what energy
would be needed? The atomic masses in amu are:
1 H 1 = 1.007825;
181
73 Ta =
180.948007;
182
74 W = 181.948301
[University of Durham 1963]
8.64 In the reaction
48 Ca +
16 O →
49 Sc +
15 N, the Q-value is −7.83 MeV. What is
the minimum kinetic energy of bombarding
16 O ions to initiate the reaction?
At this energy, estimate the orbital angular momentum in units of of the ions
for grazing collision. Take R = 1.1 A
1/3 fm.
8.2.11 Cross-sections
8.65 Calculate the thickness of Indium foil which will absorb 1% of neutrons incident at the resonance energy for Indium (1.44 eV) where σ = 28, 000 barns.
At. Wt of Indium = 114.7 amu, density of Indium = 7.3 g/cm
3 .
[Andhra University]
8.66
60 Co is produced from natural cobalt in a reactor with a thermal neutron flux
density of 5 × 10
12 n cm
−2 s
−1 . Determine the maximum specific activity.
Given σ act = 20 b.