An ionizing radiation detector includes a p-type semiconductor single crystal substrate having first and second major planar opposing surfaces, where the p-type semiconductor single crystal substrate is doped with n-type dopant atoms, and where a concentration of deep level acceptor defects is greater than a concentration of the n-type dopant atoms in the p-type semiconductor single crystal substrate; a cathode electrode on the first major planar opposing surface of the p-type semiconductor single crystal substrate, and a plurality of anode electrodes on the second major planar opposing surface of the p-type semiconductor single crystal substrate.