Physics – 5.2.1 Detection of radioactivity | e-Consult

An alpha particle detector, typically a thin sheet of material with a thin window, is less effective than a Geiger-Müller tube for measuring the intensity of alpha radiation for the following reasons:

• Low penetrating power of alpha particles: Alpha particles have a very short range and are easily stopped by materials like paper or air. This means that only a small fraction of the alpha particles emitted by the source actually reach the detector.
• Limited detection area: Due to the low penetrating power, the alpha particle detector needs to be very close to the source to detect a significant number of alpha particles. This limits the area that can be effectively measured.
• Inefficient detection: Even when an alpha particle does reach the detector, it may not always cause ionisation within the detector material, resulting in a missed detection.
• Geiger-Müller tube efficiency: The Geiger-Müller tube is designed to detect all types of ionising radiation, including alpha particles. It has a much larger detection area and a more efficient mechanism for detecting ionisation, resulting in a more reliable and accurate measurement of the alpha particle intensity.

Therefore, while an alpha particle detector can be used, a Geiger-Müller tube is generally preferred for measuring the intensity of alpha radiation due to its greater sensitivity and efficiency.