Significant leakage in an ionization chamber could occur due to which of the following?

Significant leakage in an ionization chamber is likely to occur due to dust accumulation on the chamber input connectors. This dust can interfere with the electrical connections and the proper functioning of the chamber, potentially leading to inaccurate readings or the escape of the ionization current. Clean and unobstructed connectors are essential to ensure that the chamber accurately detects and measures ionizing radiation. When dust or debris accumulates, it may result in a compromised seal or affect the chamber's ability to maintain its intended operational environment, resulting in leakage or erroneous output.

The other options, while they may implicate various issues with the functionality of an ionization chamber, do not directly lead to leakage as clearly as dust accumulation does. Worn-out electrical components may result in failures or errors in measurement, but they do not specifically indicate a leakage pathway. Excess radiation exposure might contribute to wear or damage over time, but does not instantly cause leakage. Incorrect calibration can lead to measurement inaccuracies but does not contribute to a leakage scenario specifically related to the physical integrity of the chamber or its input connectors.