  This paper gives a construction of certain asymptotic observables (Araki-Haag
detectors) in ground state representations of gapped quantum spin systems. The
construction is based on general assumptions which are satisfied e.g. in the
Ising model in strong transverse magnetic fields. We do not use the method of
propagation estimates, but exploit instead compactness of the relevant
propagation observables at any fixed time. Implications for the problem of
asymptotic completeness are briefly discussed.
