Inclusive Prompt Photon Production in Polarized pp Collisions at HERA-N

We present a NLO study of inclusive polarized prompt photon production in a conceivable fixed target $pp$ mode of HERA with longitudinally polarized protons at $\sqrt{s}=39$ GeV. We analyze the sensitivity of the corresponding double spin asymmetry to the proton's polarized gluon distribution $\Delta g$ and estimate the expected statistical precision in its determination. The main theoretical uncertainties in the predictions are examined.