DETERMINATION OF THE BACKGROUND OF 3He-FILLED PROPORTIONAL COUNTERS USED FOR LOW-LEVEL NEUTRON MEASUREMENTS

Area of Science:

• Nuclear physics
• Radiation detection
• Metrology

Background:

• Low-level neutron measurements are crucial for environmental monitoring and underground laboratory experiments.
• Distinguishing neutron signals from detector background is a significant challenge in these measurements.
• 3He spherical proportional counters are commonly used in Bonner sphere spectrometers for neutron detection.

Purpose of the Study:

• To develop a method for accurately identifying and characterizing background signals in low-level neutron measurements.
• To address the challenge of differentiating neutron-induced signals from detector-originated background noise.
• To provide a generalizable solution applicable to 3He spherical proportional counters used in neutron spectrometry.

Main Methods:

• Experimental measurements were conducted in a controlled underground laboratory environment (UDO, Asse salt mine).
• Bayesian parameter estimation techniques were employed for detailed data analysis.
• Focus on analyzing pulse height spectra to identify background contributions within 3He proportional counters.

Main Results:

• A robust method was successfully developed to determine the background in low-level neutron measurements.
• The analysis yielded a general parameterized function capable of describing the background pulse height spectrum.
• This function enables better discrimination between neutron signals and detector background.

Conclusions:

• The developed Bayesian analysis provides an effective solution for background characterization in 3He proportional counters.
• The parameterized function offers a valuable tool for improving the accuracy of low-level neutron flux determination.
• This advancement is significant for applications requiring precise neutron measurements in challenging environments.