Patent ID: 8426824

Claim:
A detector configured to measure characteristics of an energetic particle beam generated by a radiation source, the detector comprising: a plurality of sensors arranged in the path of the particle beam, the sensors configured such that the beam crosses the sensors in a sequential order; a processor configured to acquire and process signals produced by the sensors when the beam crosses one or more of the plurality of sensors; and a beam modification device configured to vary the energy of the particle beam, the beam modification device being located in the path of the particle beam and in-between the plurality of sensors and the radiation source, the beam modification device comprising an element in the beam path having a variable thickness and being configured such that the thickness encountered by the beam when crossing the element is varied by varying the relative position of the beam and the element; the processor configured to receive the signals of the plurality of sensors in dependence of the energy variation of the particle beam, and the processor configured to process the signals obtained in dependency of the energy variation for determining the characteristics.