In the gamma-ray experiment, the Cs-137 source of photon energy 0.662 MeV and
Co-60 source of photon energy 1.173 MeV and 1.332 MeV were used for gamma-ray
emission. To set up this transmission geometry, a steel stand was made to hold the detector
and its surrounded lead shielding. A vertical arrangement was established and well aligned.
This design is illustrated as in Figure 3.1.