نتایج جستجو برای: rk ionization chamber
تعداد نتایج: 81022 فیلتر نتایج به سال:
The kerma-area product (PKA) is a useful quantity to establish the reference levels in diagnosis of conventional X ray examinations. A KAP meter can be calibrated in laboratory or in situ, where it is used. The patient dose calibrator (PDC) is a new equipment from Radcal that measures PKA. It was manufactured following the IEC 60580 recommendations. The aim of this study was to calibrate the PD...
-Two parallel-plate ionization chambers were projected, constructed and evauated for use in high energy electron beams. They were constructed using the two plastic materials recommended for clinical dosimetry protocols, i.e. acrylic and polystyrene. Both chambers have cylindrical shape with entrance windows in aluminized Mylar and they are open to the air. The acrylic chamber has a 2 mm air gap...
Correction factors for the contribution of X-rays transmitted through the diaphragm of a free-air ionization chamber and those scattered from the surface of the diagram aperture are obtained by Monte Carlo simulation for two free-air ionization chambers for various diaphragm aperture sizes, X-ray energies, and source to chamber distances. The dependences of these contributions on conditions are...
Recent dosimetry protocols for clinical high-energy electron beams recommend measurements of absorbed dose-to-water with a plane-parallel or cylindrical ionization chamber. For well-guarded plane-parallel ionization chambers, the ionization chamber perturbation factor in water, p(Q), has a recommended value of unity in all protocols. This assumption was investigated in detail in this study for ...
Dedicated ionization chamber was built and installed to measure the energy loss of very heavy nuclei at 2.7 MeV/u produced in fusion reactions in inverse kinematics (beam of Pb). After going through the ionization chamber, products of reactions on C, O targets are implanted in a Si detector. Their identification through their alpha decay chain is ambiguous when their half-life is short. After c...
The Gammamed Plus 192Ir high dose rate brachytherapy sources were calibrated using the therapy level ionization chambers (0.1 and 0.6 cc) and the well-type chamber. The aim of the present study was to assess the accuracy and suitability of use of the therapy level chambers for in-air calibration of brachytherapy sources in routine clinical practice. In a calibration procedure using therapy ion ...
The use of the "thimble" ionization chamber (Fingerhutkammer) has in the past been the only method for comparing the primary X-ray standards of different laboratories, hence the precise calibration of two thimble chambers is discussed in this paper. Five principal factors determine the accuracy of such a calibration, and it is shown that the errors are all, in general, in the same direction. It...
A guarded cylindrical graphite ionization chamber of nominal volume 1000 cm3 was designed and fabricated for use as a reference standard for low-dose rate 137Cs brachytherapy sources. The air kerma calibration coefficient (N(K)) of this ionization chamber was estimated analytically using Burlin's general cavity theory, as well as by the Monte Carlo simulation and validated experimentally using ...
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