Correction factors for the INER-improved free-air ionization chambers calculated with the Monte Carlo method

Lin, Uei-Tyng; Chu, CH

doi:10.1016/j.apradiso.2005.12.009

Cited by 19 publications

(12 citation statements)

References 7 publications

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“…The Free-air ionization chamber (FAC) is used in the primary standard dosimetry laboratory (PSDL) to measure the air kerma (Kinetic Energy Released in Matter) of medium and low X-rays energy [1]. The secondary standard dosimetry laboratory (SSDL) is an intermediate ring between the PSDL laboratories and users.…”

Section: Introductionmentioning

confidence: 99%

Free-air ionization chamber, FAC-IR-300, designed for medium energy X-ray dosimetry

2017

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The primary standard for X-ray photons is based on parallel-plate free-air ionization chamber (FAC). Therefore, the Atomic Energy Organization of Iran (AEOI) is tried to design and build the free-air ionization chamber, FAC-IR-300, for low and medium energy X-ray dosimetry. The main aim of the present work is to investigate specification of the FAC-IR-300 ionization chamber and design it. FAC-IR-300 dosimeter is composed of two parallel plates, a high voltage (HV) plate and a collector plate, along with a guard electrode that surrounds the collector plate. The guard plate and the collector were separated by an air gap. For obtaining uniformity in the electric field distribution, a group of guard strips was used around the ionization chamber. These characterizations involve determining the exact dimensions of the ionization chamber by using Monte Carlo simulation and introducing correction factors. K: Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc); Detector modelling and simulations II (electric fields, charge transport, multiplication and induction, pulse formation, electron emission, etc); Gaseous detectors 1Corresponding author.

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Section: Introductionmentioning

confidence: 99%

Free-air ionization chamber, FAC-IR-300, designed for medium energy X-ray dosimetry

2017

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“…Todays, Free-air ionization chambers (FACs) are used in the primary standard dosimetry laboratory (PSDL) for obtaining air kerma of medium and low energy X-rays [1]. A primary standard is an instrument of the highest metrological quality that permits determination of the unit of the specified quantity from its definition [2].…”

Section: Introductionmentioning

confidence: 99%

“…This work focused on the use of ionization chamber. Several investigations are done for designing the free-air free-air ionization chamber as X-ray dosimeter on PSDL level [1,4,5].…”

Section: Introductionmentioning

confidence: 99%

Investigation of electric field distribution on FAC-IR-300 ionization chamber

2016

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One of the important parameters for establishing charge particle equilibrium (CPE) conditions of free-air ionization chamber is an electric field distribution. In this paper, electric field distribution inside the ionization chamber was investigated by finite element method. For this purpose, the effects of adding guard plate and guard strips on the electric field distribution in the ionization chamber were studied. it is necessary to apply a lead box around the ionization chamber body to avoid of scattered radiation effects on the ionization chamber operation, but the lead box changes the electric field distribution. In the following, the effect of lead box on the electric field distribution was studied. Finally, electric field distribution factor (k field ) was calculated by the simulation. The results of the simulation showed that presence of the guard plate and guard strips, and applying a suitable potential to lead box, a convergence of k field to 1 was achieved. K: Detector modelling and simulations II (electric fields, charge transport, multiplication and induction, pulse formation, electron emission, etc); X-ray detectors 1Corresponding author.

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“…Para que a câmara de ionização de ar-livre seja utilizada como um sistema padrão primário é necessária a determinação de diversos fatores de correção. Dentre eles estão os relacionados com: atenuação de fótons no ar entre a janela de entrada e o meio do volume sensível (OLIVEIRA, 2010), perda de elétrons no volume sensível (BURNS, 2001;LIN & CHU, 2006;LAITANO et al, 2005), espalhamento e transmissão de fótons pelas bordas do diafragma (KUROSAWA & TAKATA, 2005;BURNS & KESSLER, 2009;KASHIAN et al, 2012), transmissão pelas paredes do diafragma (DOS SANTOS, 2011),…”

Section: No Laboratório De Calibração De Instrumentos (Lci) Do Institunclassified

“…Como mencionado anteriormente, uma série de fatores de correção (k i ) são fundamentais na determinação absoluta da grandeza kerma no ar com as câmaras de ionização de ar-livre. Alguns desses fatores dependem não só das propriedades da câmara como também da energia do feixe a que ela será submetida (LIN & CHU, 2006 SALVAT et al, 2008), EGS4 (NELSON et al, 1985, permitiram a obtenção desses fatores de correção com uma incerteza satisfatória.…”

Section: Fatores De Correçãounclassified

Caracterização de uma câmara de ionização ar-livre em feixes diretos de raios X utilizados em mamografia

Lima¹

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At this work stability and characterization tests were undertaken on a Victoreen free-air ionization chamber, model 481. The tests were realized using direct X-ray beams as a contribuition for its establishment as a primary standard system of the quantity air kerma. The characterization tests were: saturation curve, ion collection efficiency, polarity effect, response linearity with the air kerma rate and response linearity with the chamber volume variation. The ion collection efficiency allowed the determination of the ion recombination factor. Most of the test results showed agreement with the limits established by international standards. Furthermore, the air attenuation factors for the mammography beams with aluminum and molybdenum filters were obtained. The factors for photon transmission and scattering at the diaphragm edges were also determined for mammography beams with aluminum filter and for the standard beam with molybdenum filter.

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Correction factors for the INER-improved free-air ionization chambers calculated with the Monte Carlo method

Cited by 19 publications

References 7 publications

Free-air ionization chamber, FAC-IR-300, designed for medium energy X-ray dosimetry

Free-air ionization chamber, FAC-IR-300, designed for medium energy X-ray dosimetry

Investigation of electric field distribution on FAC-IR-300 ionization chamber

Caracterização de uma câmara de ionização ar-livre em feixes diretos de raios X utilizados em mamografia

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