The use of n-strips on p-type silicon for microstrip detectors can extend the lifetime of irradiated devices because of the profile of the electric field. Here I have collected the results with the first successful n-in-p prototypes. The ATLAS-SCT geometry detectors were produced by Micron Semiconductor on a Liverpool design. The strip isolation was achieved by individual p-stops.

And here is the first evidence (January 2001) of improvement in term of the most relevant performance of particle detectors: the Charge Collection Efficiency (CCE) of an irradiated n-in-p is compared with the CCE of a standard and an oxygen-enriched p-in-n detectors after 3 10¹⁴ protons cm^-2. The noise performances as a function of bias for the same detector are here shown. The improvement of the CCE is entirely due to the geometry of the electric field in the n-in-p diode structure and NOT to a lower full depletion voltage. This latter is not improved using p-type bulk, as it is shown here after 3 10¹⁴ protons cm^-2.

Miniature (1x1 cm^-2, 100 strips) n-in-p capacitively coupled, polysilicon biased microstrip detectors have been designed by Liverpool and produced by CNM Barcelona to allow the study of their charge collection properties up to 7.5 10¹⁴ protons cm^-2 (24 GeV/c proton irradiations performed in the CERN/PS IRRAD1 facility, thanks to M. Glaser). Extremely good results, very encouraging for the use of this solution for the LHC upgrade to a factor  ~ 10 increased luminosity, have been obtained and here summarised.

Miniature (1x1 cm^-2, 100 strips) n-in-p capacitively coupled, polysilicon biased microstrip detectors have been designed by Liverpool and produced by Micron Semiconductor. They were used for neutron irradiation to confirm the excellent results obtained with the CNM detectors irradiated with protons. The excellent radiation hardness has been confirmed also with these neutron irradiation (performed in Ljubljana, thanks to the IJS group). The comparison of the preliminary results obtained after neutron irradiations are  here compared with the previous proton results. Synthetically, the p-type substrate microstrip detectors can be operated to the extreme doses anticipated for the Super LHC (with their performances tested with charged and neutral hadron fluxes, to prove their functionality at different radii where different type of particles dominate the spectrum, namely charged particles below 20cm radius and back-scattered neutrons for larger radii) and no deterioration due to reverse annealing is observed when CCE measurements are performed, instead of CV ones.