Patent ID: 8044365

Claim:
A ionization chamber system comprising: a radiation detector providing an ionization detector defining a first volume and providing for a detection of ionized gas in the first volume at a first collection electrode; a second radiation detector positioned within the first volume and defining a second volume within the first volume and providing for the detection of radiation in the form of an electrical signal at a second collection electrode, the first volume being electrically separated from the second volume; wherein radiation passing through the second volume also passes through the first volume providing current at the first and second collection electrodes; further including an computer executing a stored program and receiving radiation signals from the first and second radiation detectors to provide a correction for at least one of the radiation signals by evaluating the signals of the first and second radiation detector to correct for partial volume effects caused by radiation beams having an axial cross-section smaller than a corresponding cross-section of the first volume along the axis.