Dhaka University Journal of Applied Science & Engineering

• Farzana Hasan Shashi
  Department of Electrical and Electronic Engineering, University of Dhaka, Dhaka, Bangladesh
• Nafisa Tabassum
  Department of Electrical and Electronic Engineering, University of Dhaka, Dhaka, Bangladesh
• Md. Khalidur Rahman
  Department of Physics, Bangladesh University of Textiles, Dhaka, Bangladesh
• Md. Faisal Rahman
  Department of Nuclear Engineering, University of Dhaka, Dhaka, Bangladesh
• Md. Mahidul Haque Prodhan
  Department of Nuclear Engineering, University of Dhaka, Dhaka, Bangladesh
• Zahid Hasan Mahmood
  Department of Electrical and Electronic Engineering, University of Dhaka, Dhaka, Bangladesh

The study regulates the absorbed dose to water as well as output factors for small fields using IAEA TRS-398 protocol and corrects the results by determining a cross-calibration factor for small fields using German dosimeter standard DIN 6809-8. Herein, we collected several datasets of small-field output factor for two separate values of X-ray energy, 6 MV and 10 MV, from a Varian CLINAC 2100 linear accelerator. The measurements for the datasets had been taken at a depth of 10 cm and varied between 10 × 10 cm² to 2 × 2 cm². Using the Multi-Leaf Collimator (MLC), the fields were outlined and the jaws (secondary) were preserved at 10 × 10 cm². With a PTW TM60012 silicon diode detector, the measurements were made. The volume of this detector is sufficiently small to collect a complete ionization reading for a small-field having a size of 2 × 2 cm². The calibration factors obtained from 4 × 4 cm² were 1.038 (for 6MV X-Ray) and 1.042 (for 10MV X-Ray). This calibration factors can successfully reproduce the institutional output factors from diode detector readings with a variation of maximum 0.6% to minimum 0.1%.

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