Effect of lining radiotherapy room walls by composite ceramic on fast neutron attenuation

Abstract EN

This work is concerned with the study of attenuation properties of ceramic composite materials with different percentages of lead oxide and barite for fast neutrons emitted from a Californium-252 neutron source.

Measurements were performed using a narrow collimated beam emitted from a Californium-252 source, which emits about 1.3 x107 neutrons/second and housed in a specially made collimator.

The transmitted fast neutron spectrum through the investigated materials was measured by a neutron/gamma spectrometer with single crystal of stilbene scintillator.

Discrimination against undesired pulses of gammas was achieved electronically by a pulse shape discrimination method.

The measured pulse amplitude distributions of recoil protons were converted to energy spectrum of fast neutrons by a double differentiation method.

The derived fast neutron distributions are presented for ceramic samples of different thicknesses.

These spectra were used to derive the total fast neutron removal cross sections.

The measured spectra show that the ceramic shield with 5% barite additives is more effective for fast neutron attenuation