Performance of a double metal n-on-n and a Czochralski silicon strip detector read out at 40 MHz

The R&D undertaken by the VELO group in order to produce a sensor that satisfies the tight radiation hardness, efficiency, resolution and low material requirements of LHCb has resulted in the choice of an n-on-n double metal layer solution. First measurements of the performance of the latest prototype and its related front end electronics, designed to function at the LHC speed of 40 MHz, are presented here. In addition, research has been carried out into new materials which could retain good performance in high radiation environments at and beyond the LHC, and could provide an alternative for a possible VELO upgrade. For the first time a full size Czochralski silicon detector sample with 50$\mu$m pitch strips has been irradiated with high energy protons and its performance has been measured in a test beam with 40 MHz electronics. The results of this test will be presented.