CAJ | 학술논문

根据三轴谱仪的安装位置及后续结构,利用蒙特卡罗方法模拟计算了中子三轴谱仪样品处的中子谱,获得了中子均匀性、注量率等参数.模拟结果表明:采用双聚焦单色器的中子注量率是采用平板单色器中子注量率的1.54倍,但中子分布均匀性变差,垂直发散度增大到约4°;聚焦单色器的聚焦长度对中子均匀性无影响,但聚焦长度越长其垂直发散度越小;入射单色中子波长λ<0.4 nm时,用热解石墨做过滤器比较合适,而当λ≥0.4 nm时,用铍做过滤器更合适一些.
근거삼축보의적안장위치급후속결구,이용몽특잡라방법모의계산료중자삼축보의양품처적중자보,획득료중자균균성、주량솔등삼수.모의결과표명:채용쌍취초단색기적중자주량솔시채용평판단색기중자주량솔적1.54배,단중자분포균균성변차,수직발산도증대도약4°;취초단색기적취초장도대중자균균성무영향,단취초장도월장기수직발산도월소;입사단색중자파장λ<0.4 nm시,용열해석묵주과려기비교합괄,이당λ≥0.4 nm시,용피주과려기경합괄일사.
According to layout of a triple-axis spectrometer (TAS),neutron beam parameters at the sample position,such as the homogeneity,divergence and flux,were calculated by Monte-Carlo simulation. The results show that using a double-focusing monochromator,the beam flux is 1.54 times larger,but the neutron distribution is worse,than using a flat monochromator,while the vertical maximum divergence increases to 4°. Vertical divergence of the neutrons decreases with increasing focusing lengths,while the beam homogeneity does not change obviously. A pyrolytic graphite (PG) filter is suitable for neutrons in wavelengths of less than 0.4 nm,while a Be filter is better than PG filter for neutrons in wavelengths of longer than 0.4 nm.