Extended Bonner sphere spectrometer for dynamic neutron spectrum on HL-2A

The extended Bonner sphere spectrometer (EBSS) at the HL-2A tokamak for the neutron spectrum is described. This device was developed on the basis of previous Bonner sphere spectrometry (BSS), aiming to obtain a more accurate neutron spectrum in the HL-2A tokamak hall. The previous BSS contained eight Bonner spheres (BS). This EBSS contains 13 ³He-filled detectors embedded in polyethylene spheres (PS), pre-amplifiers, and a parallel processing data acquisition system (DAQ). A response matrix is simulated in Geant4 taking the effect of the environment into account.