Geiger Counter
Safety Warnings
Warning: Radioactive Source Handling
Warning: High Voltage Warning
Purpose
Demonstrates detection of ionizing radiation with a Geiger-Müller counter. Students hear the random clicking of decay events, observe the difference between background and source count rates, and see that radioactive decay is a stochastic process following Poisson statistics.
Figure 1:
Complete Geiger counter setup showing the scaler-ratemeter unit with digital display, the detector probe, and a sample card prepared for measurement. The analog meter displays counts per minute in real time.
Figure 2:
The detector system with a prepared sample card adjacent to the probe. Note the change in count reading, demonstrating the accumulation of detected radiation events over time.
Figure 3:
Sample positioning technique showing the card being placed directly under the detector probe for optimal counting geometry. The enclosed design helps reduce background interference.
Figure 4:
Final measurement configuration with sample fully positioned under the detector. The cumulative count continues to increase as radioactive decay events are detected, illustrating the statistical nature of nuclear decay.