An ideal for selection of short-lived particles by a focusing crystal

An experimental technique for selection of the short-lived particles by means of a focusing crystal is proposed. A target (to produce short-lived's) and a focusing crystal are to be arranged so that the crystal traps into channeling mode the particles emerging from the region downstream of the target only. The particles emerging from the target directly, cannot be trapped in the crystal. In this way one can trap the decay products of short-lived particles to carry them out of the background; the trapped beam can be bent, e.g., onto the experimental setup. The technique can handle the particles with decay length c/spl tau/ down to a few microns. The capabilities of the technique, resolution, and efficiency are analyzed.