The development of CVD diamond tracking detectors for high luminosity experiments at the LHC

Data from the May 1995 test beam runs at CERN have been analysed to measure the signal-to-noise ratio, spatial resolution and charge collection distance of a CVD diamond tracking detector with a pitch of 50 μm. The signal-to-noise ratio for the diamond detector was measured to be in the range 8:1 (using the most probable signal) to 12:1 (using the mean). The detector had a corresponding spatial resolution of σ = 12.9 μm. The effect of irradiating, or 'pumping', the detector with a 90Sr source for a prolonged period (44 hours) was also studied. The pumping effects were measured by comparing distributions before and after irradiation. The spatial resolution was measured to be σ = 10.4 σm before pumping and σ = 12.9 μm after pumping; a decrease of ∼ 24% is observed. The charge collection distance was measured to be 49 μm before pumping and 85 μm after pumping; a factor of 1.7 higher. From the 1995 data runs, elastic Compton scattering at HERA, e+p → e+pγ, has been used to obtain a measurement of integrated luminosity. The 1994 luminosity was measured to be 2.88 ± 0.09(stat) -0.11(syst)+0.14(syst) pb-1 and the 1995 luminosity to be 6.35 ± 0.14(stat) -0.20(syst)+0.34(syst) pb-1. The corresponding luminosity values obtained using the luminosity monitor are 2.988 ± 0.045 pb-1 and 6.362 ± 0.095 pb-1 respectively, and are in good agreement with the results obtained from Compton Scattering. Elastic Compton scattering has also been used for a measurement of the photon density of the proton. The results can be interpreted as the fraction of the proton's momentum carried by the electromagnetic field which surrounds the proton. Data and theory compare favourably. (author)