Features
- Vented sensitive volume of 30 cm3
- Suitable as high precision reference chamber for radiation protection dosimetry
- Very flat energy response within a wide range
- Radioactive check device (option)
The cylinder stem chamber is 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 certificate. Air density correction is required for each measurement. A radioactive check device and an appropriate holding device are available.
Specifications
| Type of product | vented cylindrical ionization chamber |
|---|---|
| Application | radiation protection measurements |
| Measuring quantity | photon equivalent dose, exposure |
| Nominal sensitive volume | 30 cm3 |
| Design |
not waterproof, vented |
| Reference point |
on chamber axis, 27 mm from chamber tip |
| Direction of incidence | radial |
| Nominal response | 1 µC/Gy |
| Chamber voltage | 400 V nominal ± 500 V maximal |
| Energy response | < ± 4 % (40 keV … 60Co) |
| Directional response in air | ≤ ± 0.5 % for for rotation around the chamber axis for tilting see diagram page 63 |
| Leakage current | ≤ ± 10 fA |
| Stem leakage | ≤ 1 pC/(Gy·cm) |
Materials and measures
| Wall of sensitive volume | 1 mm PMMA, graphited |
|---|---|
| Total wall area density | 119 mg/cm2 |
| Dimension of sensitive volume |
radius 15.5 mm length 51 mm |
| Central electrode | graphite coated Al, diameter 14 mm |
| Outer dimensions |
diameter 33 mm length 335 mm |
| Build-up cap | PMMA, thickness 3 mm |
Ion collection efficiency at nominal voltage
| Ion collection time | 1.3 ms |
|---|---|
| Max. dose rate for ≥ 99.5 % saturation ≥ 99.0 % saturation |
60 mGy/s |
| Max. dose per pulse for ≥ 99.5 % saturation ≥ 99.0 % saturation |
50 µGy |
Useful Ranges
| Radiation quality | 30 keV … 1.3 MeV |
|---|---|
| Temperature | (10 … 40) °C (50 … 104) °F |
| Humidity | (10 … 80) %, max 20 g/m3 |
| Air pressure | (700 … 1060) hPa |
Options
T48010 Radioactive check device 90Sr
T23237 Chamber holding device for check device
Parts
TN23361 Cylinder stem chamber 30 cm3,connecting system BNT
TW23361 Cylinder stem chamber 30 cm3, connecting system TNC
TM23361 Cylinder stem chamber 30 cm3, connecting system M
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