Organic scintillators response function modeling for Monte Carlo simulation of Time-of-Flight measurements

• Published in: Applied radiation and isotopes 2012-07, Vol.70 (7), p.1367-1369
• Main Author: Carasco, C.
• Format: Article
• Language: English
• Subjects: GEANT4; MCNP; Neutron; Organic scintillation detectors; ROOT
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2011.11.013

In neutron Time-of-Flight (TOF) measurements performed with fast organic scintillation detectors, both pulse arrival time and amplitude are relevant. Monte Carlo simulation can be used to calculate the time–energy dependant neutron flux at the detector position. To convert the flux into a pulse height spectrum, one must calculate the detector response function for mono-energetic neutrons. MCNP can be used to design TOF systems, but standard MCNP versions cannot reliably calculate the energy deposited by fast neutrons in the detector since multiple scattering effects must be taken into account in an analog way, the individual recoil particles energy deposit being summed with the appropriate scintillation efficiency. In this paper, the energy response function of 2″×2″ and 5″×5″ liquid scintillation BC-501A (Bicron) detectors to fast neutrons ranging from 20keV to 5.0MeV is computed with GEANT4 to be coupled with MCNPX through the “MCNP Output Data Analysis” software developed under ROOT (Carasco, 2010). ► GEANT4 has been used to model organic scintillators response to neutrons up to 5MeV. ► The response of 2″×2″ and 5″×5″ BC501A detectors has been parameterized with simple functions. ► Parameterization will allow the modeling of neutron Time of Flight measurements with MCNP using tools based on CERN's ROOT.