Experimental method for beta spectrum determination and comparison of the efficiency of a Geiger-Müller detector for beta and gamma radiation.

Generally, the Geiger-Müller detector is widely used in nuclear laboratories due to its relatively low cost, making it a suitable solution for laboratories with limited budgetary resources. However, this detector has significant limitations, notably its inability to discriminate the energy levels of the detected radiation, or even to clearly distinguish the type of incident radiation (β, γ, or α). This characteristic makes the determination of the beta particle energy spectrum difficult, or even inaccessible by direct methods. Similarly, determining the detector efficiency as a function of energy is complex, which complicates the comparison of the detector efficiency for beta and gamma radiation. In this context, the present work proposes an experimental method carried out in our laboratory using a non-portable Geiger-Müller detector, aiming to estimate the beta particle spectrum using the ESTAR simulation program, and then to determine the intrinsic efficiency for beta radiation as a function of energy. Finally, a comparison of the intrinsic efficiencies obtained for beta and gamma radiation is performed using a cesium-137 source. This work also presents a pedagogical approach that can be exploited in teaching, particularly for practical work in nuclear physics intended for students.