B S SANDHU*, M B SADDI, B SINGH and B S GHUMMAN

Physics Department, Punjabi University, Patiala 147 002, India

*  Author for correspondence

Abstract.

The scattering and absorption differential cross sections for nonlinear QED process such as double photon Compton scattering have been measured as a function of independent final photon energy. The incident gamma photons are of 0.662 MeV in energy as produced by an 8 Ci ¹³⁷ Cs radioactive source and thin aluminum foils are used as scatterer. The two simultaneously emitted photons in this process are detected in coincidence using two NaI(T1) scintillation detectors and a slow-fast coincidence set-up of 30 nsec resolving time. The measured values of scattering and absorption differential cross sections agree with theory within experimental estimated error.

Keywords:  Double photon Compton scattering; scattering and absorption cross sections; coincidence spectra; coincidence events.

Pacs Nos.  13.60.-r; 13.60.Fz; 32.80.-t; 32.80.Wr; 32.80.Cy