Detection of the background suppressed Compton scattered peaks for the 180O° reflected 511 keV γ-ray by the γ-γ coincidence technique

In the present project work we have carried out an experimental technique where background suppressed Compton scattered (180o) peaks for the 511 keV γ-ray have been detected by the γ-γγcoincidence spectroscopic technique. Here we use positron annihilated two oppositely (∼ 180°) directed 511 keV γ-γrays. Positrons from a radioactive nucleus (²²Na) have been used for the present work.

Positron is an antiparticle of electron. Both positron and electron has a rest mass of m_oc² = 511 keV. Positrons normally annihilate with an electron in the medium (e.g., solid, liquid, gas etc.) normally emitting two oppositely directed 511 keVγγγrays. In the present project, we have used two identical High Purity Germanium (HPGe) detector placed at 180o angle. Detailed electrons and circuit diagram will be discussed in the experimental setup sections. After setting up the γ-γγcoincidenceγspectrometer the peaks for the 180° Compton scattered 511 keV γ-ray (∼ 0.33m_oc² and 0.66m_oc²) have nicely been identified.