Conceptual designs for IR optics at C-Zero

Two possible conceptual optical designs for a stand-alone C0 IR insert were presented. Both inserts are optically transparent to the rest of the machine, with no impact on Run IIb Tevatron operating parameters. Both design variations require high-field LHC-like quadrupoles for the final focus triplet. In the first version, with enhanced dipoles creating space for separators in the arcs, collisions can be created at all 3 IP's simultaneously. Stronger dipoles also free more than 26 m of space for the detector. At C0, β* is limited to ge50 cm by βmax in the IR triplets. The second version of the IR has neither new dipoles nor new arc separators. Collider scenarios have either B0 and D0 at collision, or just C0. At C0, β* can be decreased to 40 cm, but the price paid is a substantial reduction in free space available for the detector. This first pass at C0 IR designs has left a number of questions unresolved. A few of these outstanding issues that a second iteration of the IR designs must address are discussed