Measuring the X-ray background in the reionization era with first generation 21 cm experiments

The X-ray background during the epoch of reionization is currently poorly constrained. We demonstrate that it is possible to use first generation 21 cm experiments to calibrate it. Using the semi-numerical simulation, 21cmFAST, we calculate the dependence of the 21 cm power spectrum on the X-ray background flux. Comparing the signal to the sensitivity of the Murchison Widefield Array (MWA) we find that in the redshift interval z = 8-14 the 21 cm signal is detectable for certain values of the X-ray background. We show that there is no degeneracy between the X-ray production efficiency and the Ly alpha production efficiency and that the degeneracy with the ionization fraction of the intergalactic medium can be broken.