Features
- Small-sized sensitive volume 0.016 cm3, vented to air
- Minimized directional response
- Aluminum central electrode
- Radioactive check device (option)
The 31016 PinPoint 3D chamber is ideal for dose measurements in small fields as encountered e.g. in IORT, IMRT and stereotactic beams. Relative dose distributions can be measured with high spatial resolution in any direction. The waterproof, fully guarded chamber can be used in air, solid state phantoms and in water.
Specifications
| Type of product | vented cylindrical ionization chamber |
|---|---|
| Application | dosimetry in high-energy photon beams |
| Measuring quantities | absorbed dose to water, air kerma, exposure |
| Reference radiation quality | 60Co |
| Nominal sensitive volume | 0.016 cm3 |
| Design | waterproof, vented, fully guarded |
| Reference point | on chamber axis, 2.4 mm from chamber tip |
| Direction of incidence | radial |
| Pre-irradiation dose | 2 Gy |
| Nominal response | 400 pC/Gy |
| Long-term stability | ≤ 1 % per year |
| Chamber voltage | 400 V nominal ± 500 V maximal |
| Polarity effect | < 1 % |
| Directional response in water | ≤ ± 0.5 % for rotation around the chamber axis, ≤ ± 1 % for tilting of the axis up to ± 110° |
| Leakage current | ≤ ± 4 fA |
| Cable leakage | < 1 pC/(Gy·cm) |
Materials and measures
| Wall of sensitive volume | 0.57 mm PMMA, 1.19 g/cm3 0.09 mm graphite, |
|---|---|
| Total wall area density | 85 mg/cm2 |
| Dimensions of sensitive volume |
radius 1.45 mm length 2.9 mm |
| Central electrode | Al 99.98, diameter 0.3 mm |
| Build-up cap | PMMA, thickness 3 mm |
Ion collection efficiency at nominal voltage
| Ion collection time | 60 µs |
|---|---|
| Max. dose rate for ≥ 99.5 % saturation ≥ 99.0 % saturation |
19 Gy/s |
| Max. dose per pulse for ≥ 99.5 % saturation ≥ 99.0 % saturation |
1.0 mGy |
Useful Ranges
| Chamber voltage | ± (100 … 400) V |
|---|---|
| Radiation quality | 60Co … 50 MV photons |
| Field size | (2 x 2) cm2 … (30 x 30) 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
T48002.1.008 Chamber holding device for check device
Parts
TN31016 PinPoint 3D chamber 0.016 cm3, connecting system BNT
TW31016 PinPoint 3D chamber 0.016 cm3, connecting system TNC
TM31016 PinPoint 3D chamber 0.016 cm3, connecting system M
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