Silicon microstrip detector

A semiconductor particle detector uses narrow conducting strips on depleted silicon to measure the position of an ionizing particle. The collecting electric field transports the generated electrons and holes; the induced signals identify the traversed strips.

A localized ionization signal can be collected or induced on adjacent strips through diffusion and the weighting fields of the readout electrodes. Combining their analogue signals estimates the impact position within a strip pitch, improving on binary strip position resolution when noise and calibration permit.

If a single strip of pitch $w$ reports only its centre and the impact position has a uniform distribution, the position error is uniform on $[-w/2,w/2]$. Its variance is $w^{-1}{\int }_{-w/2}^{w/2}{x}^{2}dx=w^2/12$. Charge sharing and analogue readout can improve this resolution.