subroutine imo1( conj, add, xs, t0, dt, nt, zz,     tt )
integer          conj, add,             nt, 				it, iz
real                            t0, dt,     zz(nt), tt(nt),    t, xs, zsquared
call conjnull(   conj, add,                 zz,nt,  tt,nt)
do it= 1, nt {  t = t0 + dt*(it-1)
	zsquared =  t * t - xs * xs
	if ( zsquared >= 0.) {  iz = 1.5 + (sqrt( zsquared) - t0) /dt
		if ( iz > 0 ) {	if( conj == 0 )
					tt(it) = tt(it) + zz(iz)
				else
					zz(iz) = zz(iz) + tt(it)
	 	 		}
	 	}
	}
return; end