The neutron detection temperature, also called the neutron energy, indicates a free neutron's kinetic energy, usually given in electron volts. The term temperature is used, since hot, thermal and cold neutrons are moderated in a medium with a certain temperature. Accurate neutron energy measurements are essential in many areas of application, such as nuclear safeguards, plasma diagnostics, radiation therapy, etc. Spectrometry based on time-of-flight, nuclear reaction and nuclear recoil are existing techniques that have been widely used in many applications. The Capture-gated method using a loaded liquid scintillator, which is based on the coincidence measurement of the scattering signal and the neutron-capture signal, is a robust and reliable method for fast neutron spectrometry.