Comparison between CLYC-6 and 3He for thermal neutron detection

Area of Science:

• Nuclear Instrumentation
• Materials Science

Background:

• Development of efficient and reliable thermal neutron detectors is crucial for various applications.
• 3He gas detectors have been a standard but face supply limitations.
• Cerium-doped lithium yttrium chloride scintillators offer potential alternatives.

Purpose of the Study:

• To investigate the performance of a lithium-6 enriched Cs2LiYCl6:Ce (CLYC-6) crystal for thermal neutron detection.
• To compare its intrinsic efficiency and gamma-ray discrimination capability against a standard 3He counter.
• To evaluate detector performance under varying gamma-ray background conditions.

Main Methods:

• Characterization of CLYC-6 crystal and a 3He counter (2.3 atm).
• Determination of intrinsic neutron detection efficiency via thermal neutron irradiation.
• Evaluation of gamma-ray discrimination using a mixed neutron/137Cs radiation field.

Main Results:

• CLYC-6 demonstrates an intrinsic efficiency per unit volume approximately 6.45 times greater than the 3He counter.
• Both detectors effectively reject gamma rays up to fluence rates of ~10^5 cm^-2·s^-1.
• At higher gamma-ray fluence rates (~10^6 cm^-2·s^-1), CLYC-6 experiences dead time losses, while 3He counters show pile-up effects.

Conclusions:

• CLYC-6 offers significantly higher volumetric thermal neutron detection efficiency.
• Both CLYC-6 and 3He detectors maintain comparable gamma-ray rejection under moderate background radiation.
• Performance degradation occurs at high gamma-ray intensities for both detector types, limiting reliability.