A technique for verifying the input response function of neutron time-of-flight scintillation detectors using cosmic...

Area of Science:

• Nuclear Fusion Diagnostics
• Particle Detection Instrumentation

Background:

• Accurate interpretation of DD/DT fusion neutron time-of-flight (nTOF) signals is crucial for Z-facility experiments.
• Instrument Response Functions (IRFs) must be deconvolved from nTOF signals for precise analysis.
• Traditional IRF measurement relies on specialized sub-nanosecond radiation pulse calibration facilities.

Purpose of the Study:

• To present a novel, simplified method for measuring the IRF of nTOF detectors.
• To utilize cosmic radiation as a calibration source for pulse-counting mode nTOF detectors.
• To validate the accuracy of this cosmic radiation method against established calibration techniques.

Main Methods:

• nTOF detectors were operated in pulse-counting mode using cosmic radiation.
• The IRF was characterized by measuring throughput delay and full-width-at-half-maximum.
• Results were compared with IRFs from detectors calibrated using a LINAC bremsstrahlung accelerator.

Main Results:

• The cosmic radiation method yielded consistent IRF measurements for nTOF detectors.
• IRF metrics agreed within a few percent with those obtained from LINAC calibration.
• The agreement held true across different photomultiplier bias settings.

Conclusions:

• Cosmic radiation offers a viable and simple alternative for measuring nTOF detector IRFs.
• This method can verify if a detector's IRF has drifted since its initial calibration.
• The findings support ongoing diagnostics integrity checks at facilities like the Z-facility.