粘结碳化硼材料中子屏蔽性能及制备工艺研究

中子准直器在中国散裂中子源(CSNS)的谱仪上起着限制束流截面与发散度的作用,准直器的结构设计中通过在中子飞行管上间隔设置B4C阻挡块可以起到阻挡、吸收屏蔽杂散中子的作用,为此研制了粘结碳化硼中子阻挡块,并对其成型工艺进行了研究,确定了成型最佳粉体尺寸、粘结剂含量和固化温度.对该中子屏蔽材料的中子衰减系数计算结果表明,波长为0.1×10-10、1×10-10和15×10-10m中子通过该材料的线性衰减系数分别为3.42、30.4和449.9 cm-1.力学冲击和热重实验结果也表明该材料符合在CSNS谱仪中子束线屏蔽使用中的性能要求.

Research on neutron shielding property and preparation process of bonded B4C materials

Neutron Collimators used in Chinese Spallation Neutron Source (CSNS) are critical beamline components in controlling neutron beam cross section and divergence. Typical neutron collimators consist of series of B₄C blocks fixed inside a vacuum flying tube that stop and absorb the undesired neutrons. In this work, a bonded B₄C-epoxy composite was developed and factors of the preparation process including B₄C powder size, epoxy content and curing temperature were studied and optimized for its application in neutron instrumentation. It is estimated that linear attenuation coefficients of 0.1×10-10, 1×10-10 and 15×10-10 m wavelength neutrons in this material are about 3.42,0.4and 449.9cm-1 respectively. Mechanical impact and thermal-gravimetric experiments tested and verified its applicability for neutron beamline applications.