The circular plane-parallel transmission chambers are used for dose monitoring in combination with calibration benches. The sensitive volumes are designed as twin-chambers with 2.5 mm measuring depth each and a diameter of 155 mm (model 786) or 148 mm (model 34014). The chamber walls and the electrodes are made of polyimide (Pl) of 0.025 mm thickness each with graphite layer. The chambers are guarded. The external diameter of the chamber housing is 230 mm. Two holes with 6 mm threads serve for mechanical chamber fixation.
Two chamber versions are available: model 786 is used together with dosemeters having the input circuits on ground potential, and model 34014 is used together with dosemeters having the input circuits on high voltage.