Features
Features
- Waterproof, semiflexible design for easy mounting in scanning water phantoms
- Increased sensitive volume for low level measurements
- Sensitive volume 0.3 cm3, vented to air
- Radioactive check device (option)
The 31013 semiflexible chamber is ideal for precise dose measurements and for the measurement of dose distributions in scanning water phantom systems. The chamber is used as an alternative for the 31010 chamber in cases where increased signal levels are required and spatial resolution along the axis of the chamber can be compromised.
Specifications
| Type of product | vented cylindrical ionization chamber |
|---|---|
| Application | absolute dosimetry in radiotherapy beams |
| Measuring quantities | absorbed dose to water, air kerma, exposure |
| Reference radiation quality | 60Co |
| Nominal sensitive volume | 0.3 cm3 |
| Design | waterproof, vented, fully guarded |
| Reference point | on chamber axis, 9.5 mm from chamber tip |
| Direction of incidence | radial |
| Nominal response | 10 nC/Gy |
| Long-term stability | ≤ 1 % per year |
| Chamber voltage | 400 V nominal ± 500 V maximal |
| Polarity effect at 60Co | < 1 % |
| Photon energy response |
< ± 2 % (100 kV … 280 kV) < ± 4 % (100 kV … 60Co) |
| Directional response in water | < ± 0.5 % for rotation around the chamber axis and for tilting of the axis up to ± 10° |
| Leakage current | ≤ ± 4 fA |
| Cable leakage | ≤ 1 pC/(Gy·cm) |
Materials and measures
| Wall of sensitive volume | 0.55 mm PMMA, 1.19 g/cm3 0.15 mm graphite, 0.82 g/cm3 |
|---|---|
| Total wall area density | 78 mg/cm2 |
| Dimension of sensitive volume |
radius 2.75 mm length 16.25 mm |
| Central electrode | Al 99.98, diameter 1.1 mm |
| Build-up cap | PMMA, thickness 3 mm |
Ion collection efficiency at nominal voltage
| Ion collection time | 80 µs |
|---|---|
| Max. dose rate for ≥ 99.5 % saturation ≥ 99.0 % saturation |
14 Gy/s 28 Gy/s |
| Max. dose per pulse for ≥ 99.5 % saturation ≥ 99.0 % saturation |
0.8 mGy 1.5 mGy |
Useful Ranges
| Chamber voltage | ± (100 … 400) V |
|---|---|
| Radiation quality |
66 keV … 50 MV photons (10 … 45) MeV electrons (50 … 270) MeV protons |
| Field size | (4 x 4) cm2 … (40 x 40) cm2 |
|
Temperature |
(10 … 40) °C (50 … 104) °F |
| Humidity |
(10 … 80) %, max 20 g/m3 |
| Air pressure | (700 … 1060) hPa |
Options
T48012 Radioactive check device 90Sr
T48002.1.004 Chamber holding device for check device
Parts
TN31013 Semiflex chamber 0.3 cm3,connecting system BNT
TW31013 Semiflex chamber 0.3 cm3, connecting system TNC
TM31013 Semiflex chamber 0.3 cm3, connecting system M
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