SiC基中子探测器对热中子的响应

Thermal neutron response of neutron detector based on SiC

以SiC二极管和中子转换材料6 LiF为基础,研制了SiC基中子探测器,并用241 Am源与临界装置分别研究了SiC基中子探测器的α粒子响应、热中子响应。结果表明:SiC基中子探测器能够满足241 Am源α粒子的计数测量,但由于SiC二极管灵敏区薄,故不能用于5.48MeV的α粒子能谱测量;SiC基中子探测器对热中子响应良好,不同功率下,脉冲幅度谱中可清晰看到由6 Li(n,α)3 H的反应产物α粒子、3 H粒子形成的双峰;脉冲幅度甄别法可将γ射线及电子学噪声甄别掉;在直接测量与符合测量中,SiC基中子探测器的计数率均与临界装置功率成线性关系,且直接测量的线性度比符合测量的线性度好,最好可达0.999 97。研究表明:降低肖特基接触金属的厚度、增加其外延层厚度、提高其外延层品质,可将SiC二极管用于带电粒子能谱测量。

With SiC diode and neutron conversion material 6LiF, neutron detector based on SiC was fabricated. The alpha- particle and thermal neutron response of neutron detector based on SiC were studied by 241 Am-alpha source and critical assembly, respectively. Excellent signals from the neutron detector to both alpha-particles and thermal neutrons have been observed. The neutron detector can be applied to particle intensity measurement. But because of the thin epitaxial layer, the detector can not be used for 5.48 MeV alpha-particle energy measurement. With different reactor power, the double peaks of alpha particles and 3 H pnrticles in the spectrum were obviously observed. A small amount of energy from gamma-ray was deposited in SiC neutron de- tector, which could be discriminated by pulse height discriminator. Count rate of SiC neutron detector was linear with critical as- sembly power, and which has a linearity of 0. 999 97. After all, for SiC diode, it can be used for energy measurement by decrea- sing the thickness of Scotty contact metal and increasing the depth and qualities of epitaxial layer.