Roos® Electron Chamber
- Vented sensitive volume of 0.35 cm3
- Reference chamber for precise absolute electron dosimetry
- Perturbation-free design and minimal polarity effect
- Suitable for use in water and in solid state phantoms
The Roos electron chamber1 is used as a reference electron chamber. It is recommended by the IAEA2 for high precision electron dosimetry in radiation therapy. The chamber has a 4 mm wide guard ring to exclude any perturbation effect even at low electron energies. The polarity effect is negligible (< 0.5 % at 10 MeV). The energy response is only influenced by the stopping power ratios water / air. The chamber is waterproof for absolute dose and depth dose measurements in a water phantom. The coated acrylic entrance window has a thickness of 1.1 mm. The nominal useful energy range is from 2 MeV to 45 MeV. A calibration certificate with a 60Co calibration factor given in absorbed dose to water is included. Air density correction is required for each measurement. A radioactive check device with adapter is available as an option. The chamber cable length is 1.08 m.
1 The Roos electron chamber was developed in cooperation with Dr. Roos, PTB-Braunschweig, German Federal Institute of Physics and Metrology (National Laboratory of Germany)
2 Technical Report No. TRS-381. The Use of Plane Parallel Ionization Chambers in High Energy Electron and Photon Beams, IAEA (International Atomic Energy Agency), Vienna 1997