CAJ | 학술논문

为了准确测量长计数器到源的距离，需要确定长计数器等效中心的位置。对单能中子源，在等效中心处，长计数器可被视为“点”探测器，其探测效率与其工作距离成平方反比关系。如果事先知道长计数器在不同工作距离下的探测效率，则可以利用该平方反比关系确定长计数器等效中心的位置。利用加速器中子源，分别在0．144 MeV、0．565 MeV、1．2 MeV、2．5 MeV、5．1 MeV以及14．8 MeV等6个能量点刻度了De Pangher长计数器距靶心不同距离处的探测效率，利用平方反比关系得到长计数器在各能量下的等效中心位置。由实验数据拟合出长计数器等效中心到其前端面距离r0与中子能量En的关系曲线，结果表明在0．144～14．8 MeV范围内，r0与中子能量的自然对数近似呈线性关系。
위료준학측량장계수기도원적거리，수요학정장계수기등효중심적위치。대단능중자원，재등효중심처，장계수기가피시위“점”탐측기，기탐측효솔여기공작거리성평방반비관계。여과사선지도장계수기재불동공작거리하적탐측효솔，칙가이이용해평방반비관계학정장계수기등효중심적위치。이용가속기중자원，분별재0．144 MeV、0．565 MeV、1．2 MeV、2．5 MeV、5．1 MeV이급14．8 MeV등6개능량점각도료De Pangher장계수기거파심불동거리처적탐측효솔，이용평방반비관계득도장계수기재각능량하적등효중심위치。유실험수거의합출장계수기등효중심도기전단면거리r0여중자능량En적관계곡선，결과표명재0．144～14．8 MeV범위내，r0여중자능량적자연대수근사정선성관계。
In order to accurately measure the distance between a long counter and the source, the position of the long counter’ s equivalent center should be determined.For single-energy neutron source, the long counter can be regarded as a "point"detector at its equivalent center, whose detection efficiency is in the inverse square relationship with working distance.If the detection efficiency of the long counter at different distances is known, then the equivalent center can be determined using the inverse square relationship.With the accelerator neutron source, detection efficiency of a De Pangher long counter at different distances to the source is calibra-ted.The neutron energy changes at 0.144 MeV、0.565 MeV、1.2 MeV、2.5 MeV、5.1 MeV and 14.8 MeV during the calibration.Based on these efficiency, the distance( r0 ) from the equivalent center to the long count-er’s front face is got using the inverse square relationship.Curve of the r0 -En is plotted and the result shows that, at the range of [0.144, 14.8] MeV, the equivalent center of the De Pangher long counter is proportional to the nature logarithm of the neutron energy.