DESIGN, CONSTRUCTION AND TEST OF GAMMA IONIZATION CHAMBERS

Area of Science:

• Medical Physics
• Radiation Dosimetry
• Nuclear Instrumentation

Background:

• Ionization chambers are the gold standard for radiation dose measurement.
• Developing reliable and accurate ionization chambers is crucial for dosimetry applications.
• Comparing different wall materials (graphite and PMMA) provides insights into chamber performance.

Purpose of the Study:

• To fabricate and characterize graphite-walled and PMMA-walled ionization chambers.
• To compare the performance parameters of these different ionization chambers.
• To investigate the influence of anode diameter on the saturation absorbed dose in PMMA-walled chambers.

Main Methods:

• Fabrication of one graphite-walled and two PMMA-walled ionization chambers.
• Experimental testing and comparison of characteristic parameters (e.g., linearity, repeatability).
• FLUKA code simulations for relative energy response analysis.

Main Results:

• Graphite-walled and PMMA-walled chambers exhibited similar performance characteristics.
• Relative energy response was within 4% across a broad energy range (50 keV to 50 MeV) via simulation.
• Experimental data confirmed excellent linearity and repeatability for the fabricated chambers.
• Maximum saturation absorbed dose was found to vary with anode diameter in PMMA chambers.

Conclusions:

• Both graphite and PMMA are suitable materials for ionization chamber construction.
• The fabricated ionization chambers demonstrate reliable performance for dosimetry.
• Anode geometry is a significant factor affecting dose measurement accuracy in PMMA chambers.