This letter reports measurements of a new type of double alignment channeling process which simultaneously uses the ``channeling effect'' and ``blocking effect'' in a relatively simple geometry. Results for the case of 500‐keV He ions impinging on ZnO single crystals are shown to be in fair agreement with a calculation of the magnitude of this effect based on the Lindhard model of particle channeling. It is shown that the sensitivity of this measurement to the detection of atomsnoton normal lattice sites is a factor of 10–50 greater than in the usual channeling experiment.