Abstract: The relativistic effect experimental spectrometer can be used to verify the

relativistic relationship conveniently and accurately between the energy and momentum of

fast electrons. Two comprehensive experiments are carried out to measure the thickness of

aluminum sheet and foil respectively. It can not only help students to un- derstand the nuclear

physics experimental technology and applications，but also achieve the multiple applications of

instruments，and improve using efficiency.

Key words: relativistic effect experimental spectrometer, thickness, absorption coefficient, energy, quality stopping ability