SU-FF-T-157: Determination of the Effective Chamber Position of 2D Ion Chamber Array Using An HDR Afterloading Device

2006 ◽  
Vol 33 (6Part9) ◽  
pp. 2085-2085
Author(s):  
P Biggs
Keyword(s):  
Ion Chamber

scholarly journals EP-1693 Determination of the angular dependence of a CC04 ion chamber

2019 ◽  
Vol 133 ◽  
pp. S910-S911
Author(s):  
A. Prado ◽  
Á. Gaitán ◽  
M. Manzano ◽  
M. Leonor
Keyword(s):  
Angular Dependence ◽  
Ion Chamber

Determination of penumbral widths from ion chamber measurements

2005 ◽  
Vol 32 (12) ◽  
pp. 3636-3640 ◽  
Author(s):  
D. Herrup ◽  
J. Chu ◽  
H. Cheung ◽  
M. Pankuch
Keyword(s):  
Ion Chamber ◽  
Chamber Measurements

scholarly journals Calibration of spectrometric detectors for air kerma rates in environmental monitoring

2020 ◽  
Vol 35 (4) ◽  
pp. 323-330
Author(s):  
Marcel Ohera ◽  
Daniel Sas ◽  
Petr Sladek
Keyword(s):  
Monte Carlo Simulation ◽  
Hpge Detector ◽  
Absorbed Energy ◽  
Dose Rates ◽  
Ion Chamber ◽  
Air Kerma ◽  
Hpge Detectors ◽  
Different Types ◽  
Plastic Detector

The spectrometric systems, especially based on NaI(Tl) and HPGe detectors, are used for nuclide identification and calculation of their activities from the ground measurements and air-borne monitoring. The determination of the air kerma (dose) rates is also very important for environmental measurements. In such cases, the detectors should be calibrated for air kerma (dose) rates in nGyh?1 or ?Gyh?1. A simple calibration of NaI(Tl), HPGe as well as plastic detectors for the low-level air kerma rates is presented in this contribution. This calibration is based on comparing the relative absorbed energy rate in detectors (MeVs?1) calculated from spectra with the air kerma rates calculated by the Monte Carlo simulation and supplementary to the data from the RSS Reuter&Stokes high pressure ion chamber. This method also eliminates the conversion from the non-air kerma rates in crystals to the air kerma rates. Three different types of small cylindrical detectors were calibrated for the air kerma rates from the background of 26 nGyh?1 to some tens of ?Gyh?1 in the energy range to the maximum of 3 MeV. The results of calibrations of the 3" x 3" NaI(Tl), HPGe detector and a small plastic detector (made of polystyrene) including soxme examples of environmental measurements are presented.

Determination of Chemical Valence States in Dilute Samples Using a Combination of Fluorescence Ion Chamber and PIN Photon Diode

2005 ◽  
pp. 1015
Author(s):  
Y. N. Xie ◽  
J. Zhang ◽  
J. Liu ◽  
T. Liu ◽  
T. D. Hu ◽  
...  
Keyword(s):  
Ion Chamber ◽  
Valence States

scholarly journals An Efficiency Studying of an Ion Chamber Simulation Using Vriance Reduction Techniques with EGSnrc

2019 ◽  
Vol 9 (3Jun) ◽  
Author(s):  
L T Campos ◽  
L A Magalhães ◽  
C E V De Almeida
Keyword(s):  
Monte Carlo ◽  
Ionization Chamber ◽  
Variance Reduction ◽  
Reference Conditions ◽  
Computation Time ◽  
Efficient Computation ◽  
Ion Chamber ◽  
Variance Reduction Techniques ◽  
Reduction Techniques

Background: Radiotherapy is an important technique of cancer treatment using ionizing radiation. The determination of total dose in reference conditions is an important contribution to uncertainty that could achieve 2%. The source of this uncertainty comes from cavity theory that relates the in-air cavity dose and the dose to water. These correction factors are determined from Monte Carlo calculations of ionization chambers. The main problem of this type of calculation is the extremely long computation time to achieve reasonable statistics.Objective: The main purpose of this work is to present a combination with variance reduction techniques for the case of an ionization chamber in water.Methods: The egs_chamber code allows for very efficient computation of ionization chamber doses and dose ratios by using various variance reduction techniques, and also permits realistic simulations of the experimental setup due to the use of EGSnrc C++ library. Russian roulette and Photon Cross Section Enhancement were used with egs_chamber code. Tests were performed to obtain the parameters of variance reduction techniques resulting in a maximum efficiency.Results: It can be seen that the parameters which result in improved Monte Carlo calculation of the efficiency values are XCSE 64 and Russian Roulette (RR) 128.Conclusion: This study determines the parameters of variance reduction techniques that result in an optimal computational efficiency.

Statistical analysis on 2D array of ion chamber performance

2015 ◽  
Vol 14 (2) ◽  
pp. 194-201
Author(s):  
Akbar Anvari ◽  
Seyed Mahmoud Reza Aghamiri ◽  
Seyed Rabie Mahdavi ◽  
Parham Alaei
Keyword(s):  
Statistical Analysis ◽  
Field Size ◽  
Coefficient Of Determination ◽  
Detector Response ◽  
Maximum Deviation ◽  
High Dose ◽  
Ion Chamber ◽  
Ionisation Chamber ◽  
2D Array

AbstractPurposeIn this work, dosimetric properties of the PTW Octavius detector in and out of the irradiation field have been evaluated. The 2D array of ion chambers has the potential to simplify the linear accelerator QA and pre-treatment verification.Materials and methodsThe evaluation was performed using customised written codes in Matlab and SPSS software for statistical analysis.ResultsExperiments indicate that the reproducibility and stability of the measurements were excellent; the detector showed the same signal with a maximum deviation of <0·5% in the short and long term. Comparisons of the ion chamber with the detector showed the same results with a maximum deviation of ~0·1%. As the detector response is linear with the dose, it can be used for the measurement at regions of high-dose gradient effectively. Logarithmic regression y=0·127 ln(x)+0·729 for detector signal and field size changes yielded a coefficient of determination of 0·997. The dose value decreases with increase in source-to-surface distance, which was modelled using a binomial regression with a coefficient of determination of 0·998 that agrees with the ionisation chamber measurement within 1%.ConclusionOn the basis of the measurements and comparisons performed, this system is a reliable and accurate dosimeter for quality assurance in radiotherapy.

TU-E-224A-04: Determination of Total Scatter Factors for Stereotactic Radiation Fields by Optimized Fitting of Readings From a Small Ion Chamber and a Mini-Diode

2006 ◽  
Vol 33 (6Part18) ◽  
pp. 2214-2214
Author(s):  
W Du ◽  
F Lerma ◽  
N Sakthi ◽  
R George ◽  
M Schaefer ◽  
...  
Keyword(s):  
Stereotactic Radiation ◽  
Ion Chamber ◽  
Radiation Fields
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