Chromatic corrections and dynamic aperture in the HERA electron ring. Pt. 1

Achromatic optical solutions for the HERA e--ring are presented and discussed. The dynamic aperture for the three different optics is studied by particle tracking and perturbation theory. We found a significant advantage of quasi-superperiodic solutions with respect to the non-periodic solutions and an advantage of a 6-sextupole family solution with respect to a 2-family solution. The sextupole acceptance for the preferred optical solution is as large as 27 standard deviations at a beam energy of 35 GeV. (orig.)