The TVL is the average amount of material needed to absorb 90% of all radiation, i.e., to reduce it to a tenth of the original intensity. 1 TVL is greater than or equal to log 2 (10) or approximately 3.32 HVLs, with equality achieved for a monoenergetic beam.

2021年9月29日 · Tables showing the Half-Value (HVL) and Tenth-Value Layer (TVL) for penetration of x-rays and gamma rays through shielding material. The data is presented for broad beam conditions with heavily filtered x-rays and for gamma radiation.

1.定义 半值层就是将入射的X或γ射线光子数（照射量率）衰减一半（50%）所需要的屏蔽层厚度，用HVT或 HVL表示。 以此类推，分值层（1/10值层）就是将入射的 X 或γ射线光子数（照射量率）衰减到1/10（10%）的屏蔽层厚度，用TVT或 TVL 表示。 2.HVT和TVT的关系 HVT和 TVT之间有下列关系∶. HVT=0.301TVT. TVT=3.32HVT. 在实际辐射防护设计中，泄漏辐射多与散射辐射混合在一起，当分别计算出的对散射辐射与泄漏辐射的屏蔽厚度相差一个 TVT值或更大时，则应采 …

2025年3月15日 · Half-value layer (HVL) is the thickness of a material required to reduce the air kerma of an X-ray or gamma-ray beam to half its original value. HVL is most accurately measured under narrow-beam geometry, as broad-beam setups allow scatter to reach the detector, leading to an underestimation of attenuation unless corrected.

2016年4月1日 · HVL and TVL values provide useful information about the penetration of a specific radiation in a specific material. In this study, TVL and HVL thickness are calculated for concretes with...

2021年9月29日 · In the above table, TVT and TVL (and HVT and HVL) are the same quantity) In the preceding sections of this handbook presentation we established the following which is recognised in modern radiation shielding literature. The TVL value for Co-60 in lead was shown to be 4 cm. The TVL value for Cs-137 in lead was shown to be 2.2 cm.

use the associated half-value layer (HVL) or tenth-value layer (TVL) (see Section 6.2). In Table 7.1 values of the HVL and TVL are presented for a wide range of x-ray tube voltages with lead, iron, or concrete shields. For radiological protection of personnel from medical, dental, and indus

2024年8月4日 · To figure out a material’s lead equivalent, we use the half value layer (HVL) and tenth value layer (TVL) formulas. The HVL is the thickness that cuts radiation in half. The TVL is the thickness that reduces it by 90%. These formulas help us find out how thick a material needs to be for the right radiation protection.

半值层 (HVL) 是放射学、放射治疗和核物理领域的一个关键概念，表示将辐射强度降低一半所需的材料厚度。 它是设计辐射防护屏蔽、优化医学影像技术和确保核设施安全的一个关键参数。 自发现辐射以来，半值层概念一直是理解和利用辐射的基础。 它有助于量化辐射穿透不同材料的能力，因此在放射性物质的安全处理和应用中发挥着至关重要的作用。 计算半值层的公式为： HVL = \frac {0.693} {\mu} H V L = μ0.693. 其中： 1/cm 1/cm)。 如果材料的线性衰减系数 (\mu μ) 为 …

2024年12月26日 · The half-value layer (HVL) and tenth-value layer (TVL) are also related to the absorption rate, with HVL being the thickness that reduces the intensity by half and TVL reducing it by a factor of ten. These concepts find applications in radiation physics and shielding design, aiding in the determination of radiation penetration and the ...