Orsay: detector configuration: reality intervenes

It turned out not to be feasible to use the Deep Space 9 mount after all. Instead, we're going to use the circular mount. Detectors are mounted on L-shaped brackets, which are put at any θ with respect to the beam line (defined from the centre of the detector) and at radial distances ranging from ~10 to ~18 cm. It's easy to mount up to four detectors in plane (i.e. φ=0 or 180), but mounting detectors out of plane will take some work.
That's reality check 1. Reality check 2 is that there just aren't enough amplifiers to go around, if we are planning to use 6 detectors. Stick with 4!
As it happens, the only feasible way to mount 6 detectors on this mount would give us less solid angle and fewer total good events than the best way of mounting four detectors. The best arrangement of four detectors I've come up with has a coverage of 7.5% solid angle, compared with 6.7% for the best feasible arrangement of six detectors.
(Both of these arrangements take into consideration the fact that we can't get closer than 5' or 1.5 cm from the beamline without frying the detectors.)

Here's the outlines of the positions of the four detectors...



...and the reaction hit patterns...



Next up: how we're actually going to mount the detectors in this configuration....