CAJ | 학술논문

本文通过理论计算和实验测量的方法，研究墙体中天然γ核素比活度就地测量问题。理论分析了不平衡状态下226 Ra、232 T h、40 K的测量方法，由实验室测量238 U的第1代子体234 T h及通过235 U和238 U的天然同位素丰度比值关系，获得典型居室墙体中235 U对226 Ra就地测量的干扰系数；利用ISOCS无源效率模拟研究了测量时墙体之间的干扰；并研究了砖块形状和墙材原料配比等因素对无源效率刻度的影响。结果表明，235 U对226 Ra就地测量的干扰系数约为0.46；Falcon 5000在居室几何条件下测量单面墙体时，经8 mm钨屏蔽后，40 K的干扰扣除系数为0.33；最后分析获得居室墙体中226 Ra、232 Th和40 K就地测量时总不确定度分别为26％、17％和15％，可用于室内环境调查。
본문통과이론계산화실험측량적방법，연구장체중천연γ핵소비활도취지측량문제。이론분석료불평형상태하226 Ra、232 T h、40 K적측량방법，유실험실측량238 U적제1대자체234 T h급통과235 U화238 U적천연동위소봉도비치관계，획득전형거실장체중235 U대226 Ra취지측량적간우계수；이용ISOCS무원효솔모의연구료측량시장체지간적간우；병연구료전괴형상화장재원료배비등인소대무원효솔각도적영향。결과표명，235 U대226 Ra취지측량적간우계수약위0.46；Falcon 5000재거실궤하조건하측량단면장체시，경8 mm오병폐후，40 K적간우구제계수위0.33；최후분석획득거실장체중226 Ra、232 Th화40 K취지측량시총불학정도분별위26％、17％화15％，가용우실내배경조사。
The in‐situ measurement of natural γ nuclide specific activity in walls was studied through theoretical calculation and experimental measurement .The method for measuring 226 Ra ,232 Th and 40 K in non‐equilibrium state was analyzed theoretically ,and the interference coefficient from 235 U when measuring 226 Ra in‐situ was estimated by laboratory measuring 234 Th which is the first generation daughter of 238 U and according to the natural isotope abundance ratio between 235 U and 238 U .The interference in meas‐urement between the walls in the same room was studied using ISOCS passive efficiency simulation .And the effects on the passive efficiency calibration from the brick shape and raw material ratio were also studied .The results show that the interference coefficient from 235 U when measuring 226 Ra in‐situ is about 0.46 ,and the deduction coefficient of 40 K when measuring the single wall by Falcon 5000 is about 0.33 under the indoor geo‐metrical condition with 8 mm tungsten shield .The total uncertainties of in‐situ meas‐urement were analyzed ,which are respectively 26% ,17% and 15% for 226 Ra ,232 Th and 40 K in indoor walls .As a conclusion ,the in‐situ measurement can be used for indoor environment survey .