Figure 10.19
Exposure of hot particle contaminated soil (sampled 15 km north of the
Chernobyl Nuclear Power Plant) to film X, Y and Z of a Differential
Autoradiographic Imaging Sandwich. The original film size is 85 × 10 × 10
mm, exposure time was 14 days. Area (a) shows irradiation from a^90 Sr^
dominated hot particle whereas irradiation in area (b) is caused by a(^137) Cs dominated hot particle.
(Courtesy of G.I. Nageldinger, Kingston University.)
Problems
(1)^51 Ti decays to^51 V by the emission of β– particles and γ-rays. A spectroscopic examination gave the
following energies for the radiations.
Construct a reasonable decay scheme for the decay.
(2) Calculate the disintegration rate of 1 cm^3 of tritium at standard temperature and pressure. What will
the activity be after 2.5 years? The half life of tritium is 12.26 years. Express your answers in curies and
becquerels.
(3) A sample was irradiated in a neutron flux and the induced radioactivity monitored after it was
removed from the flux. The fully corrected results are presented below.
Plot a log/linear curve of activity vs time and analyse it into its components. Deduce the half-lives and
the initial activities of the components.
Time
(hours)
Activity
(counts min–^1 )
Time
(hours)
Activity
(counts min–^1 )
0 7300 4.0^481
0.5 4680 5.0^371
1.0 2982 6.0^317