A dataset of the Large-scale Modular BGO Detection Array (LAMBDA) design and test

Total Absorption Gamma-ray Spectroscopy (TAGS) provides a powerful tool for measuring complex γ transitions and has been effectively applied in the study of reactor decay heat. This paper presents the design of a new TAGS detector, named Large-scale Modular BGO Detection Array (LAMBDA), tailored for measuring β decay intensity distributions of fission products. The modular design allows the LAMBDA detector to be assembled in various configurations. The final version of LAMBDA consists of 102 identical 60 mm×60 mm×120 mm BGO crystals, exhibiting a high full-energy peak efficiency exceeding 80% at 0.5~8 MeV based on Monte Carlo simulation. Currently, about half of the LAMBDA modules have been manufactured. Tests using γ-ray sources and nuclear reactions demonstrate favorable energy resolution, energy linearity, and efficiency uniformity across the modules. Forty-eight modules have been integrated into the prototype LAMBDA-I. The capability of LAMBDA-I in β-delayed γ decay experiments was evaluated through a commissioning measurement with the 152Eu source.