The present invention relates to a device for
dosimetry monitoring of a
hadron beam, comprising n successive
ionization chambers i obtained by a serie or stack of n+1 parallel
detector plates separated from each other by a gas filled gap, each
detector plates having a collecting part comprising a collecting side insulated from a bias
voltage part comprising a bias
voltage side and ranged in a such way that the said collecting side is facing the said bias
voltage side of a subsequent
detector plate or inversely, each detector plate comprising m
layers Lk of materials, the resulting
assembly of these detector plates forming a plurality of
ionization chamber cells, characterised in that: the thicknesses Ik and the choice of the materials of each layer Lk constituting each detector plate as well as the gap of an
ionization chamber
cell i have been selected in order to satisfy the equation (I) for each
ionization chamber i, where lgi is the gas filled gap distance between two detector plates; Ik is the thickness of the corresponding layer Lk of a detector plate and; WETk is the
water equivalent thickness (WET) of the corresponding layer Lk of a detector plate.