442 8 Nuclear Physics – II
8.59 The Q- value of the reaction^16 O(d,n)^17 Fis− 1 .631 MeV, while that of the
reaction^16 O(d,p)^17 Ois+ 1 .918 MeV. Which is the unstable member of the
pair^17 O−^17 F, and what is the maximum energy ofβ-particles it emits? (n−^1 H
mass difference is 0.782 MeV)
[University of Manchester 1958]
8.60 An aluminum target is bombarded byα-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 negativeβ-particles of end point energy 18.5 KeV, calculate the differ-
ence 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 neu-
tron 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 pro-
duced 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;^18173 Ta=
180 .948007;^18274 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 ofof the ions
for grazing collision. TakeR= 1 .1A^1 /^3 fm.
8.2.11 Cross-sections ....................................
8.65 Calculate the thickness of Indium foil which will absorb 1% of neutrons inci-
dent at the resonance energy for Indium (1.44 eV) whereσ= 28 ,000 barns.
At. Wt of Indium=114.7 amu, density of Indium= 7 .3g/cm^3.
[Andhra University]
8.66^60 Co is produced from natural cobalt in a reactor with a thermal neutron flux
density of 5× 1012 ncm−^2 s−^1. Determine the maximum specific activity.
Givenσact=20 b.