A Compton-suppression detection system for use in manganese bath measurements

• A Compton-suppression system (CSS) consists of eight NE102 plastic and one NaI scintillators is proposed.
• The motivation for the proposed CSS is to improve the minimum detectable activity in a manganese bath system (MBS).
• Both MCNPX and experimental studies have been undertaken to obtain the optimum source-to-detector distance in CSS.

The manganese sulfate bath technique is a standard tool for neutron source strength measurement (Park et al., 2005). However, the dominate Compton continuum of most sodium iodide scintillators used in manganese bath systems (MBSs) does not allow the precise identification of induced gamma rays required for such measurements. In this research, to resolve this problem, a Compton-suppression system has been proposed which consists of a 2 in. by 2 in. NaI(Tl) right cylindrical scintillator as the main and a set of eight rectangular NE102 plastic scintillators of 12×12×15 cm3 dimensions as suppression detectors. Both detectors operate in anti-coincidence circuit to suppress the Compton continuum. The proposed system has been simulated with the MCNPX code with two different approaches and the corresponding measurements with 137Cs gamma-ray source and neutron-activated MnSO4 solution have been undertaken that give rise to a promising agreement.