Due to the exponential attenuation of photons in materials, thick samples will attenuate a large portion of photons. This is a source of error in methods such as neutron activation analysis, which use gamma spectroscopy to characterise a radioactive source. A method is developed to quantify the magnitude of self-shielding with the help of MCNP6. Then the mass of an unknown sample is determined by comparing the known sample mass and the photopeak counts of the unknown and the known samples following activation. The inclusion of self-shielding effects is shown to make this comparative mass analysis measurement technique more accurate. Accounting for the self-shielding effects allows the true source, instead of the shielded source, to be resolved by correcting for the photons that are attenuated as they try to escape the sample and reach the detector. The $$\gamma $$ -ray measurements were made using several samples of varying shapes.

中文翻译：

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使用 $$\gamma $$ 射线光谱法进行质量测量时自屏蔽的重要性

由于材料中光子的指数衰减，厚样品会衰减大部分光子。这是中子活化分析等方法的误差来源，这些方法使用伽马能谱来表征放射源。开发了一种在 MCNP6 的帮助下量化自屏蔽强度的方法。然后通过比较已知样品质量和未知样品和已知样品在激活后的光峰计数来确定未知样品的质量。显示包含自屏蔽效应使这种比较质量分析测量技术更加准确。考虑到自屏蔽效应，可以通过校正在试图逃离样品并到达检测器时衰减的光子来解决真实源，而不是屏蔽源。