Angular dependence of the wall correction factor for air kerma measurements using cylindrical cavity chambers

AbstractExperimental verification of our previous numerical simulation of wall effects on the terminal falling velocity of spherical particles moving slowly along the axis of a cylindrical vessel filled with a Carreau model fluid is presented. Dependences of the wall correction factor F W on the sphere to tube ratio d/D and on the dimensionless Carreau model parameters m, Λ, and η r were obtained using a finite element method. Calculated data of the wall correction factor were compared with the results of our new falling sphere experiments. The experiments were carried out in six types of cylindrical Perspex columns (16 mm, 21 mm, 26 mm, 34 mm, 40 mm, and 90 mm in diameter) filled with aqueous solutions of polymers exhibiting different degrees of shear thinning and elasticity. Seventeen types of spherical particles (1–8 mm in diameter) made of glass, ceramics, steel, lead, and tungsten carbide were used for the drop tests. Measurements of the liquid flow curves, primary normal stress differences, oscillatory, creep and recovery, stress relaxation, and stress growth tests were carried out on the rheometer Haake MARS (Thermo Scientific). A good agreement between numerically and experimentally obtained F W data was found.

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Calculation of the humidity correction factor in air kerma strength measurement for 125I and 103Pd brachytherapy sources and its uncertainty by Monte Carlo method

Annals of Nuclear Energy ◽

10.1016/j.anucene.2012.11.016 ◽

2013 ◽

Vol 54 ◽

pp. 240-244

Author(s):

S. Kashian ◽

G. Raisali ◽

H. Khalafi

Keyword(s):

Monte Carlo ◽

Monte Carlo Method ◽

Correction Factor ◽

Strength Measurement ◽

Air Kerma

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Revised correction factor for the UK national primary standard for air kerma for137Cs and60Co gamma-rays

Metrologia ◽

10.1088/0026-1394/46/5/n03 ◽

2009 ◽

Vol 46 (5) ◽

pp. L26-L26 ◽

Cited By ~ 1

Author(s):

Julia Pearce ◽

Graham Bass ◽

Simon Duane ◽

Rebecca Nutbrown ◽

David Shipley

Keyword(s):

Correction Factor ◽

Gamma Rays ◽

Primary Standard ◽

National Primary Standard ◽

Air Kerma ◽

The Uk

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Evaluation of Wall Correction Factor of INER's Air-Kerma Primary Standard Chamber and Dose Variation by Source Displacement for HDR192Ir Brachytherapy

BioMed Research International ◽

10.1155/2013/436979 ◽

2013 ◽

Vol 2013 ◽

pp. 1-8

Author(s):

J. H. Lee ◽

J. N. Wang ◽

T. T. Huang ◽

S. H. Su ◽

B. J. Chang ◽

...

Keyword(s):

Monte Carlo ◽

Monte Carlo Method ◽

Treatment Plan ◽

Primary Standard ◽

National Physical Laboratory ◽

High Dose Rate ◽

High Dose ◽

Air Kerma ◽

The Monte Carlo Method ◽

Wall Correction Factor

The aim of the present study was to estimate the wall effect of the self-made spherical graphite-walled cavity chamber with the Monte Carlo method for establishing the air-kerma primary standard of high-dose-rate (HDR)192Ir brachytherapy sources at the Institute of Nuclear Energy Research (INER, Taiwan). The Monte Carlo method established in this paper was also employed to respectively simulate wall correction factors of the192Ir air-kerma standard chambers used at the National Institute of Standards and Technology (NIST, USA) and the National Physical Laboratory (NPL, UK) for comparisons and verification. The chamber wall correction calculation results will be incorporated into INER's HDR192Ir primary standard in the future. For the brachytherapy treatment in the esophagus or in the bronchi, the position of the isotope may have displacement in the cavity. Thus the delivered dose would differ from the prescribed dose in the treatment plan. We also tried assessing dose distribution due to the position displacement of HDR192Ir brachytherapy source in a phantom with a central cavity by the Monte Carlo method. The calculated results could offer a clinical reference for the brachytherapy within the human organs with cavity.

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