Calibrating Xylene Scintillators by Characterizing Light Decay Curves in Scintillators using Cosmic Ray Muons*

HEDP and ICF facilities employ a time of flight method using plastic scintillators to measure neutron energies. The performance of an nToF system correlates to the decay time of scintillators. To reduce the decay time, xylene scintillators are quenched with oxygen becoming less efficient at producing light. Eventually, effusion of oxygen requires recalibration of the detector using a monoenergetic neutron source which is unavailable at most HEDP and ICF facilities. Given here is an update on our previous work of a possible method of in-situ calibration of xylene. A circuit was designed and built at SUNY Geneseo to output a logic pulse when a cosmic ray muon passed through three vertically aligned scintillators within a coincident timing interval. The output triggered an oscilloscope that recorded the anode signal of the middle detector. The scope traces were used to determine the middle scintillator’s response function.  If the detector’s response to cosmic ray muons is known, it can be used to determine the scintillation decay curve produced by a mono energetic neutron. As a result, the need for remote accelerator-based calibration of the xylene detectors is eliminated.