A recoil-proton spectrometer based on a p-i-n diode implementing pulse-shape discrimination

Area of Science:

• Nuclear Physics
• Particle Detection
• Spectroscopy

Background:

• Recoil-proton spectrometers are crucial for neutron detection.
• Existing detectors face limitations in minimum detectable energy due to secondary electron contributions.

Purpose of the Study:

• To develop an improved recoil-proton spectrometer with enhanced sensitivity at lower energies.
• To investigate the effectiveness of pulse-shape discrimination in reducing the minimum detectable energy.

Main Methods:

• Coupling a p-i-n diode with a polyethylene converter to form a recoil-proton spectrometer.
• Utilizing a reverse-injection configuration for the diode to optimize charge collection.
• Implementing pulse-shape discrimination based on the zero-crossing time of bipolar signals from a (CR)2-(RC)2 filter.
• Characterizing the detector's performance using monoenergetic neutrons from a Van De Graaff accelerator.

Main Results:

• The spectrometer achieved a maximum detectable energy of approximately 6 MeV.
• The minimum detectable energy was limited by secondary electrons, initially around 1.5 MeV.
• Pulse-shape discrimination reduced the minimum detectable energy to approximately 900 keV.
• The reverse-injection configuration enhanced collection times for recoil-proton generated charge carriers.

Conclusions:

• The developed recoil-proton spectrometer demonstrates effective neutron detection capabilities.
• Pulse-shape discrimination is a viable technique for improving the low-energy sensitivity of these detectors.
• The spectrometer shows promise for applications requiring precise low-energy neutron measurements.