science physics

# What is a tenth value layer?

Last Updated: 23rd April, 2020

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Definition of Tenth-value layer
Tenth-value layer or "TVL" means the thickness of a specified material that attenuates x-radiation or gamma radiation to an extent such that the air kerma rate, exposure rate, or absorbed dose rate is reduced to one-tenth of the value measured without the material at the same point.

Also question is, how is HVL calculated?

Determine the attenuation coefficient of a material. This can be found in a table of attenuation coefficient or from the manufacturer of the material. Divide 0.693 by the attenuation coefficient to determine the HVL. The half-value layer formula is HVL = = 0.693/μ.

Furthermore, what does half value layer mean? A material's half-value layer (HVL), or half-value thickness, is the thickness of the material at which the intensity of radiation entering it is reduced by one half.

Keeping this in view, why is half value layer important?

Half value layer. HVL is an important quality control test as it is used to measure whether or not there is sufficient filtration in the x-ray beam to remove low energy radiation, which can be damaging. It also helps to determine the type and thickness of shielding required in the facility.

Half-value layer (HVL) is the width of a material required to reduce the air kerma of an x-ray or gamma-ray to half its original value. This applies to narrow beam geometry only as broad-beam geometry will experience a large degree of scatter, which will underestimate the degree of attenuation. HVL = 0.693 / μ

Professional

4.2 mm

Professional

## What is mass energy absorption coefficient?

The Mass Energy-Absorption Coefficient, μen/ρ 13) represents the average fraction of the kinetic energy of secondary charged particles (produced in all the types of interactions) that is subsequently lost in radiative (photon-emitting) energy-loss processes as the particles slow to rest in the medium.

Professional

## What is meant by linear absorption coefficient?

linear absorption coefficient the fraction of a beam of radiation absorbed per unit thickness of absorber. mass absorption coefficient the linear absorption coefficient divided by the density of the absorber.

Explainer

## What is inherent filtration?

Inherent filtration refers to a permanently implemented filter in the useful beam. Inherent filtration includes the window of the x-ray tube and any permanent enclosure for the tube or source. Filters partially absorb or attenuate the x-ray beam to prevent radiation overexposure.

Explainer

## How does attenuation affect correlate with photon energy?

As the x-ray beam passes through tissue, photons get absorbed so there is less energy; this is known as attenuation. It turns out that higher energy photons travel through tissue more easily than low-energy photons (i.e. the higher energy photons are less likely to interact with matter).

Explainer

## What is half value distance?

The thickness of any given material where 50% of the incident energy has been attenuated is know as the half-value layer (HVL). The HVL is expressed in units of distance (mm or cm). Increasing the penetrating energy of a stream of photons will result in an increase in a material's HVL.

Pundit

## What is the inverse square law radiation?

The inverse square law describes the principle of dose reduction as the distance from the source increases. If radiation spreads over a spherical area, as the radius increases, the area over which the dose is distributed increases according to A=4πr^2 where A is the area, π is pi and r is the radius of the sphere.

Pundit

## What does HVL stand for?

HVL
Acronym Definition
HVL Half-Value Layer
HVL Hardware Verification Language
HVL High Voltage Laboratory
HVL Highly Volatile Liquids

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23rd April, 2020

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