Line spread function study of kinestatic charge detectors operating at high gas pressures

Area of Science:

• Medical Physics
• Radiation Detection and Imaging
• Gas-filled Detectors

Background:

• The line spread function (LSF) is critical for assessing spatial resolution in x-ray imaging systems.
• High-pressure ionization chambers offer potential for advanced digital radiography.

Purpose of the Study:

• To systematically investigate the line spread function (LSF) in the drift direction of a high-pressure ionization chamber.
• To understand how gas pressure affects LSF and spatial resolution in kinestatic charge detection (KCD) systems.

Main Methods:

• Experimental operation of a krypton-filled KCD detector at pressures up to 60 atm.
• Maintaining a constant electric field-to-gas pressure ratio during experiments.
• Analyzing the width of the LSF as a function of drift distance and gas pressure.

Main Results:

• LSF width increases with drift distance and decreases significantly with increasing gas pressure.
• Higher gas pressures lead to narrower LSF and improved Full Width at Half Maximum (FWHM).
• Evidence suggests molecular ion cluster formation at high pressures influences ion mobility.

Conclusions:

• Increasing gas pressure in high-pressure ionization chambers demonstrably improves spatial resolution for x-ray detection.
• Molecular ion cluster formation is hypothesized to explain the observed narrowing of the LSF at elevated pressures.
• Findings contribute to the development of large field-of-view digital radiographic scanners using KCD principles.