The cylindrical stem chamber has been designed as a reference chamber for absolute dosimetry to be used by secondary standard dosimetry laboratories (SSDL) and users with high quality requirements. It has very small variations of response with radiation quality from low X-ray energies up to high-energy photon radiation.
The guard ring is designed up to the sensitive volume.
The chamber is constructed with a long rigid stem of approx. 20 cm length for easy mounting in the radiation beam. An acrylic build-up cap with 3 mm wall thickness for in-air measurement in 60Co beams is included with each chamber, as well as a calibration certifiate.
Air density correction is required for each measurement. A radioactive check device with an appropriate holder is optionally available.