Approximation of the Field Components of TE and TM Modes in Waveguides and Cavities with General Cross Section
This paper shows that the field components of TE and TM modes of waveguides and cavities with general cross section can be approximated by a power series consisting of a separeble solution and nonseparable solutions of Helmholtz wave equation corresponding to the rectangular waveguide.
Use of nonseparable solutions of Helmholtz wave equation in waveguides and cavities
The letter shows how some recently discovered nonseparable solutions of the Helmholtz wave equation can be used in the synthesis of waveguides and cavities with nonconventional cross-sections, and also investigates some interesting properties.
Long term response stability of a well-type ionization chamber used in calibration of high dose rate brachytherapy sources
Well-type ionization chamber is often used to measure strength of brachytherapy sources. This study aims to check long term response stability of High Dose Rate (HDR)-1000 Plus well-type ionization chamber in terms of reference air kerma rate (RAKR) of a reference 137Cs brachytherapy source and recommend an optimum frequency of recalibration. An HDR-1000 Plus well-type ionization chamber, a reference 137Cs brachytherapy source (CDCSJ5), and a MAX-4000 electrometer were used in this study. The HDR-1000 Plus well-type chamber was calibrated in terms of reference air kerma rate by the Standards Laboratory of the International Atomic Energy Agency (IAEA), Vienna. The response of the chamber was verified at regular intervals over a period of eight years using the reference 137Cs source. All required correction factors were applied in the calculation of the RAKR of the 137Cs source. This study reveals that the response of the HDR-1000 Plus well-type chamber was well within ±0.5% for about three years after calibration/recalibration. However, it shows deviations larger than ±0.5% after three years of calibration/recalibration and the maximum variation in response of the chamber during an eight year period was 1.71%. The optimum frequency of recalibration of a high dose rate well-type chamber should be three years.