基于MCNP程序模拟计算了不同孔隙度二氧化硅介质地层14 Me V中子慢化长度与中子迁移长度。首先,模拟计算了241Am-Be中子源条件下不同孔隙度Si O2介质地层的中子通量空间分布,并利用源距均方值公式计算得到了对应的中子慢化长度LS和中子...基于MCNP程序模拟计算了不同孔隙度二氧化硅介质地层14 Me V中子慢化长度与中子迁移长度。首先,模拟计算了241Am-Be中子源条件下不同孔隙度Si O2介质地层的中子通量空间分布,并利用源距均方值公式计算得到了对应的中子慢化长度LS和中子迁移长度LM。与文献结果对比:中子特征长度LS与LM结果相对误差均值分别为1.20%与-2.60%;该结果验证了源距均方值公式计算中子特征长度的有效性和可行性。同样地,计算得到了不同孔隙度Si O2介质地层14 Me V中子的中子特征长度LS和LM;计算结果表明:14 Me V中子的中子特征长度同样随地层孔隙度的增加而降低;其中水的14Me V中子特征长度为LS=12.73 cm、LM=13.00 cm,Si O2的14 Me V中子特征长度为LS=30.08 cm、LM=34.31 cm;中子慢化长度LS结果与文献结果的相对偏差≤±3.1%。展开更多
An overall irradiation and calibration technique was introduced and applied to a test scintillation detector array. An integral conversion method was used to reduce the nonlinearity of the time difference spectrum, an...An overall irradiation and calibration technique was introduced and applied to a test scintillation detector array. An integral conversion method was used to reduce the nonlinearity of the time difference spectrum, and to improve the position determination especially for positions close to the two ends of a long scintillation bar. An overall position resolution of about 3.0 cm （FWHM） was extracted from the residual analysis method and verified by a direct measurement. Energy calibration was also realized by selecting cosmic rays at different incident angles. The bulk light attenuation lengths for the four test bars were also determined. It is demonstrated that these methods are especially efficient for calibrating large and complex detector arrays展开更多
文摘基于MCNP程序模拟计算了不同孔隙度二氧化硅介质地层14 Me V中子慢化长度与中子迁移长度。首先,模拟计算了241Am-Be中子源条件下不同孔隙度Si O2介质地层的中子通量空间分布,并利用源距均方值公式计算得到了对应的中子慢化长度LS和中子迁移长度LM。与文献结果对比:中子特征长度LS与LM结果相对误差均值分别为1.20%与-2.60%;该结果验证了源距均方值公式计算中子特征长度的有效性和可行性。同样地,计算得到了不同孔隙度Si O2介质地层14 Me V中子的中子特征长度LS和LM;计算结果表明:14 Me V中子的中子特征长度同样随地层孔隙度的增加而降低;其中水的14Me V中子特征长度为LS=12.73 cm、LM=13.00 cm,Si O2的14 Me V中子特征长度为LS=30.08 cm、LM=34.31 cm;中子慢化长度LS结果与文献结果的相对偏差≤±3.1%。
基金Supported by National Natural Science Foundation of China (10827505, 11035001, 10775003, 10905002)National Basic Research Program of China (2007CB815002)
文摘An overall irradiation and calibration technique was introduced and applied to a test scintillation detector array. An integral conversion method was used to reduce the nonlinearity of the time difference spectrum, and to improve the position determination especially for positions close to the two ends of a long scintillation bar. An overall position resolution of about 3.0 cm （FWHM） was extracted from the residual analysis method and verified by a direct measurement. Energy calibration was also realized by selecting cosmic rays at different incident angles. The bulk light attenuation lengths for the four test bars were also determined. It is demonstrated that these methods are especially efficient for calibrating large and complex detector arrays
