Study of the Neutron Energy Spectra below 1 MeV in ES#2 of the CSNS Back-n White Neutron Facility

This data is the relative energy spectra of the 0.3 eV – 1 MeV energy range for three measurement stages from 2022 to 2025 at the Back-n Laboratory of the Chinese Spallation Neutron Source (100 bin per decade (bpd) and 500 bpd versions). There are two folders in the compressed package, "100 bpd" and "500 bpd", representing the relative energy spectrum results of different bins. Both folders contain four experimental subfolders: 2022 baseline data (2022 ES2 50-15-40 folder), 2024 proton beam window replacement data (2024 ES2 50-15-40 and 2024 ES2 50-50-58 folders), and 2025 target adjustment data (2025 ES2 50-15-40 folder). Each "202X ES2 50-XX-XX" folder contains two. root files, hflux.root, which stores the relative energy spectrum and total error, and herror.root, which stores the uncertainty sub item. The relative energy spectrum and uncertainty results can be opened using the CERN ROOT software.