Ion recombination and polarity correction factors for a plane-parallel ionization chamber in a proton scanning beam

2017 ◽  
Vol 45 (1) ◽  
pp. 391-401 ◽  
Author(s):  
Małgorzata Liszka ◽  
Liliana Stolarczyk ◽  
Magdalena Kłodowska ◽  
Anna Kozera ◽  
Dawid Krzempek ◽  
...  
Keyword(s):  
Ionization Chamber ◽  
Correction Factors ◽  
Plane Parallel ◽  
Scanning Beam ◽  
Ion Recombination ◽  
Polarity Correction

scholarly journals EP-1756 Ion recombination and polarity correction for a plane-parallel ionization chamber in hadrontherapy

2019 ◽  
Vol 133 ◽  
pp. S948
Author(s):  
D. Maestri ◽  
A. Mirandola ◽  
G. Magro ◽  
A. Mairani ◽  
E. Mastella ◽  
...  
Keyword(s):  
Ionization Chamber ◽  
Plane Parallel ◽  
Ion Recombination ◽  
Polarity Correction

ION–ION RECOMBINATION COEFFICIENT: I. CORRECTION FOR ION DISTRIBUTION AND DIFFUSION LOSSES IN PLANE PARALLEL ION CHAMBERS

1967 ◽  
Vol 45 (2) ◽  
pp. 429-437 ◽  
Author(s):  
S. McGowan
Keyword(s):  
Electrode Spacing ◽  
Recombination Coefficient ◽  
Correction Factors ◽  
Ion Distribution ◽  
Ion Density ◽  
Plane Parallel ◽  
Ion Recombination ◽  
Ion Chambers ◽  
Considerable Range ◽  
And Diffusion

Correction factors to measured values of the ion–ion recombination coefficient, which are required because of nonuniform ion density and diffusion losses, are calculated from computer solutions to the differential equation for simultaneous recombination and diffusion. Results for plane-parallel ion chambers are given as a function of ion age for an initially uniform ion distribution over a considerable range of ion density and electrode spacing, and for a collimated distribution for two particular combinations of ion density and electrode spacing. Corrections to be applied to some reported experimental ion–ion recombination coefficients are estimated.

scholarly journals Dosimetric Performance of Newly Developed Farmer-Type Ionization Chamber in Radiotherapy Practice

2016 ◽  
Vol 15 (6) ◽  
pp. NP113-NP120
Author(s):  
Sathiyan Saminathan ◽  
Henry Finlay Godson ◽  
Retna Ponmalar ◽  
Ravikumar Manickam ◽  
James Mazarello ◽  
...  
Keyword(s):  
Correction Factor ◽  
Ionization Chamber ◽  
Cost Effective ◽  
High Energy ◽  
Dose Measurement ◽  
Photon Beams ◽  
Active Volume ◽  
Ion Chamber ◽  
Ion Recombination ◽  
Polarity Correction

Dose measurement with ionization chamber is essential to deliver accurate dose to the tumor in radiotherapy. The cylindrical Farmer-type ionization chamber is recommended by various dosimetry protocols for dose measurement of radiotherapy beams. The air-equivalent graphite wall Farmer-type ionization chamber (FAR 65 GB) of active volume 0.65 cm3 with aluminum as the central electrode material was fabricated. Various dosimetric parameters were studied for the newly developed ionization chamber in cobalt-60, 6 and 18 MV photon beams. The preirradiation and postirradiation leakage of the chamber was within 0.08%. The long-term stability and the stem effect of the chamber were within 0.07% and 0.3%, respectively. The sensitivity of the ionization chamber was found to be 22.15 nC/Gy. The chamber shows linear response with dose for cobalt-60, 6 and 18 MV photon beams. The ion recombination correction factor increases with increase in bias voltage. For all energies and field sizes, the polarity correction factor is almost closer to unity. The ion recombination and polarity correction measurements show that the polarizing potential and polarity recommended during the calibration of ionization chamber should be used for routine measurement to avoid the uncertainty. The chamber response is independent of dose rate and energy. The chamber is cost-effective and shows precise and reproducible response. The study carried out confirms that the newly fabricated ion chamber can be used in the measurement of absolute dose for high-energy photon beams.

Determination of ion recombination correction factors for a liquid ionization chamber in megavoltage photon beams

2015 ◽  
Vol 66 (9) ◽  
pp. 1439-1447
Author(s):  
Sang Hyoun Choi ◽  
Kum-Bae Kim ◽  
Young Hoon Ji ◽  
Chan Hyeong Kim ◽  
Seonghoon Kim ◽  
...  
Keyword(s):  
Ionization Chamber ◽  
Correction Factors ◽  
Photon Beams ◽  
Liquid Ionization Chamber ◽  
Ion Recombination ◽  
Liquid Ionization

Perturbation correction factors for the NACP-02 plane-parallel ionization chamber in water in high-energy electron beams

2006 ◽  
Vol 51 (5) ◽  
pp. 1221-1235 ◽  
Author(s):  
F Verhaegen ◽  
R Zakikhani ◽  
A DuSautoy ◽  
H Palmans ◽  
G Bostock ◽  
...  
Keyword(s):  
Ionization Chamber ◽  
Electron Beams ◽  
High Energy ◽  
Energy Electron ◽  
Correction Factors ◽  
High Energy Electron ◽  
Plane Parallel

PO-1343: Measurement of surface dose in a 1.5 T MRLinac using plane-parallel ionization chamber

2020 ◽  
Vol 152 ◽  
pp. S711
Author(s):  
B. Yang ◽  
W.W. Lam ◽  
K.K. Tang ◽  
W.K. Law ◽  
K.Y. Cheung ◽  
...  
Keyword(s):  
Ionization Chamber ◽  
Surface Dose ◽  
Plane Parallel
Sign in / Sign up

Export Citation Format

Share Document