We have investigated an unusual charge-multiplication mechanism in gases, mainly photon-mediated, that allows a controlled avalanche spread in a parallel-plate chamber. Exploiting this mode of operation, electrons can be multiplied and transferred through a succession of amplifying elements, thus constituting a multistep avalanche chamber. Several detection schemes are analysed, which provide remarkable energy, time, and position resolution both for soft X-rays and for charged particles. A gated operation of the device is described, which should allow efficient detection of particles fluxes some orders of magnitude larger than the conventional multiwire proportional chambers. Applications in several domains, such as Cherenkov ring imaging, detection of thermal neutrons, and radio-chromatography, are also discussed.