Outside the EAST experimental hall, in a laboratory, is where the gamma spectrometer is housed. The hall concrete wall has a diameter of 4 cm and is 1.5 m thick. Its collimator is perpendicular to the plasma on the equatorial plane. The wall is thick enough to give the spectrometer accurate measuring conditions. Potential neutrons are prevented from entering the detector by using a neutron attenuator. Inside the collimator is the polythene-based neutron attenuator.