plane containing the rotation and magnetic dipole axes. In this case, photons are generated which travel tangential to the local magnetic field lines, and there are beams in both the outward (away from the neutron star) and inward directions, because the accelerating gaps are populated by pair production. They considered the pulse profile of radiation produced in the outer gap and showed that a single pole will produce a broad, irregularly-shaped, emission which is particularly dense near the edge. As a result, double $\gamma$-ray pulses will be observed when the line of sight from the Earth crosses these enhanced regions of the $\gamma$-ray beam, while the inner region of the beam provides a significant amount of emission between the pulses. With a proper choice of the observer viewing angle, a wide range of peak phase separations can be accommodated. Furthermore, Chiang and Romani (1994) refined the calculation of high-energy emission from the rotation-powered pulsars based on the CHR model. Their major refinements include (i) the approximate location of the emission at each point in phase along a given line of sight was inferred by using a pulse phase map, and (ii) because the spectral emissivities at different emission points will 