Background:

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The gadolinium-loaded liquid scintillator detector is an important tool for particle detecting in the area of high energy physics and nuclear physics experiments.

Purpose:

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In this work

a large-size ø30cm×30cm gadolinium-loaded liquid scintillator detector has been developed for neutron measurement. Neutron gamma discrimination and distribution of neutron capture time of gadolinium-loaded liquid scintillator were main values of detecting performance.

Methods:

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The n-gamma discrimination of the large-size gadolinium-loaded liquid scintillator detector has been studied using a

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Cf spontaneous fission neutron source by zero-crossing method. It was observed that the neutron-gamma discrimination property of large-size gadolinium-loaded liquid scintillator detector was poor. n-gamma discrimination spectra of ø30 cm×30 cm gadolinium-loaded liquid scintillator detector within 1 μs after the fission event were captured with coincidence method based on the start signal of fission fragment from

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Cf fission chamber.

Results:

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It was observed that the neutron-gamma discrimination property of large-size gadolinium-loaded liquid scintillator detector was also poor. The time distributions of neutron and gamma in the n-gamma discrim

ination spectra were measured by time-of-flight (TOF) technique and coincidence method. The peak time difference of neutron time distribution and gamma time distribution was 2 ns. The distribution of neutron capture time was measured for a ø30 cm×30 cm gadolinium-loaded liquid scintillator detector with coincidence method based on the start signal of fission fragment from

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Cf fission chamber. The main signals of γ by neutron capture of ø30 cm×30 cm gadolinium-loaded liquid scintillator detector were in about 30 μs. The average time of neutron capture is 11 μs.

Conclusion:

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The neutron capture time property of homemade gadolinium-loaded liquid scintillator meets the experimental requirements. For the most signal of neutron and gamma within the superposition

single peak was presented in the n-gamma discrimination spectra. Therefore

the n-gamma discrimination could not be realized. The phenomenon of the poor neutron-gamma discrimination property of ø30 cm×30 cm gadolinium-loaded liquid scintillator detector was explained clearly based on the experiments.