Properties of non-DT-neutron products in neutron tubes

By using two calibrated ST401 scintillation detectors, the neutron yield of a pulse neutron tube was measured, and by adding a Pb shield before one detector, the influence of the Pb shield on neutron flux was determined. The 1 cm thick Pb shield decreases the neutron flux by 18.20%. The influence of the Pb shield on accelerator neutron sources was determined the same way. The 0.5 cm thick Pb shield decreases the neutron flux by 2.90%. The measurements of two neutron sources were simulated by Monte Carlo. Compared with the neutron tube experiment, the accelerator experiment results agree with the simulation better. The theoretical analysis shows that neutron tubes can generate much bremsstrahlung X rays, which may have harmful impact on the measurement of neutron tube yields.