Working with the AGS liaison physicists and engineers, we have analyzed a number of possible locations for our experiment. It appears that the best solution, taking all factors (including cost) into account is to place the experiment in the A3 line. It would then operate in an exclusive OR mode with the TPC. At the present time there is no approved heavy ion experiment for the TPC but a letter of intent has been submitted. However, the experiment envisioned could probably share the beam in a reasonable fashion with E864 since the TPC experiment would not require most of the beam time and the transfer between the two experiments can be made in 4 to 6 hours.
The main advantage of the A3 location is that a beam line already exists to
this location which is of higher quality than the D line, the other
possibility. A complication of the A line location is the fact that
E878, a quadrupole spectrometer-based experiment to measure yields of
antideuterons produced in 
Si beam heavy ion collisions and to search
for new states at selected values of Z/A, is to be located in that line.
Although E878 has not been approved for runs with the Au beam
(the focus of E864), it is anticipated that if the apparatus performs as
expected a gold beam run will be approved.
The current plan is to construct as much of E864 as possible while E878 is in place (the overlap occurs mainly at the front end), and, assuming no delays in schedule, to remove the E878 apparatus as soon as the winter 1993 heavy ion run ends. We would plan to install enough of the front end of E864 so that we could take some test data during the proton run in the spring and summer of 1993. The experiment, in its stage 1 design, would then be installed and would use the heavy ion run of the winter of 1994.
This plan illustrates another advantage of the A line location, namely, the ability to provide particles to the experiment during proton running. This would still be in an OR mode with the normal user of the A line during proton running. However, given the fast switching time it would seem that short test runs could be arranged. Such runs would be invaluable in getting the detector and the D/A system on the air. The alternate solution in the D line would not have permitted beams to the experiment during proton running.