  The electron beam, one of the most effective approaches to simulate the
irradiation effects of powerful pulsed X-ray in the laboratory, plays an
important role in the experiment of simulating thermodynamic effects of
powerful pulsed X-ray. This paper studies the thermodynamics equivalence
between multi-energy composite spectrum electron beam and blackbody spectrum
X-ray, which is helpful to quickly determine the experimental parameters in the
simulation experiment. The experimental data of electron beam is extrapolated
by the numerical calculation, to increase the range of energy flux. Through
calculating the blow-off impulse of blackbody spectrum X-ray irradiation, we
obtained the curve of X-ray blow-off impulse varying with energy flux, and then
found two categories of equivalent relations - equal-energy flux and
equal-impulse - by analysing the calculation results of electron beam and X-ray
blow-off impulse. Based on such relations, we could directly or indirectly
obtain the results of blackbody spectrum X-ray irradiation blow-off impulse via
electron beam experiment.
