Performance of n-in-p pixel detectors irradiated at fluences up to 5x10**15 neq/cm**2 for the future ATLAS upgrades

摘要

We present the results of the characterization of novel n-in-p planar pixeldetectors, designed for the future upgrades of the ATLAS pixel system. N-in-psilicon devices are a promising candidate to replace the n-in-n sensors thanksto their radiation hardness and cost effectiveness, that allow for enlargingthe area instrumented with pixel detectors. The n-in-p modules presented hereare composed of pixel sensors produced by CiS connected by bump-bonding to theATLAS readout chip FE-I3. The characterization of these devices has beenperformed with the ATLAS pixel read-out systems, TurboDAQ and USBPIX, beforeand after irradiation with 25 MeV protons and neutrons up to a fluence of5x10**15 neq /cm2. The charge collection measurements carried out withradioactive sources have proven the feasibility of employing this kind ofdetectors up to these particle fluences. The collected charge has been measuredto be for any fluence in excess of twice the value of the FE-I3 threshold,tuned to 3200 e. The first results from beam test data with 120 GeV pions atthe CERN-SPS are also presented, demonstrating a high tracking efficiencybefore irradiation and a high collected charge for a device irradiated at10**15 neq /cm2. This work has been performed within the framework of the RD50Collaboration.