  We present an X-ray stacking analysis of a sample of 38 submillimeter
galaxies with <z>=2.6 discovered at >4{\sigma} significance in the Lockman Hole
North with the MAMBO array. We find a 5{\sigma} detection in the stacked soft
band (0.5-2.0 keV) image, and no significant detection in the hard band (2.0-8
keV). We also perform rest-frame spectral stacking based on spectroscopic and
photometric redshifts and find a ~4{\sigma} detection of Fe K{\alpha} emission
with an equivalent width of EW>1 keV. The centroid of the Fe K{\alpha} emission
lies near 6.7 keV, indicating a possible contribution from highly ionized Fe
XXV or Fe XXVI; there is also a slight indication that the line emission is
more spatially extended than the X-ray continuum. This is the first X-ray
analysis of a complete, flux-limited sample of SMGs with statistically robust
radio counterparts.
