the energy and flux determination of BL12SW

The energy of BL12SW was determined by utilizing the elastic scattering peak of air, which was detected by a high purity Ge detector. The HP Ge detector was frist calibrated precisely using the Eu source to ensure accurate positioning of the energy peak. Subsequently, several energy points were achieved through the use of a liquid nitrogen-cooled median bent monochromator. The energy at each point was measured by the HP Ge detector. The flux measurement was conducted using a 500mm ion chamber filled with Xe gas. The detailed calculation process is outlined in the paper.