Thin-wall drift tube vertex chamber for the AMPIR spectrometer

We present the application of thin wall (36 μm) drift tubes as a vertex detector for the AMPIR spectrometer. The application of this vertex chamber is expected to improve the accuracy of the unambiguous vertex reconstruction up to ≈ 100 μm. recision wire positioning is described. The construction of the compact flat prototype of the drift tube array module is given which provides a σ = 18 μm overall uncertainty in sense wire positioning. Results of the first tests with radioactive sources and cosmic rays are presented. Other possibilities of using this cheap type of a detector are discussed.