Soft X-Ray Chamber 34013
Thin window plane-parallel chamber for dose measurements in superficial radiation therapy
- Ultra thin entrance window
- For low-energy photons from 15 kV to 70 kV
- Extremely small size
- Sensitive volume 0.005 cm3, vented
The 34013 soft X-Ray chamber is used for reference dose measurements in low-energy photon beams as used in superficial radiation therapy.
The chamber’s small size enables the user to perform measurements with excellent spatial resolution.
Correction factors needed for the determination of absorbed dose to water are available.
The chamber is designed for the use in solid state phantoms.
Specifications
| Type of product | vented plane-parallel ionization chamber |
| Application | reference dosimetry in low-energy photon beams |
| Measuring quantities | absorbed dose to water, air kerma, exposure |
| Reference radiation quality | 30 kV, HVL 0.37 mm Al (T30) |
| Design | not waterproof, vented |
| Direction of incidence | perpendicular to chamber plane |
| Nominal sensitive volume | 0.005 cm3 |
| Nominal response | 200 pC/Gy |
| Long-term stability | ≤ 1 % per year |
| Chamber voltage | 400 V nominal |
| ± 400 V maximal | |
| Reference point | inner surface of the entrance window, at the center of the window |
| Directional response | ≤ ± 1 % for tilting by ± 5° |
| Leakage current | ≤ ± 10 fA |
| Cable leakage | ≤ 1 pC/(Gy·cm) |
Materials and measures
| Entrance foil | 0.03 mm PE |
| Total window area density | 2.76 mg/cm2 |
| Sensitive volume | radius 1.45 mm |
| depth 0.9 mm | |
| Electrode | radius 0.8 mm |
Ion collection efficiency at nominal voltage
| Ion collection time | 14 μs |
| Max. dose rate for | |
| ≥ 99.5 % saturation | 0.5 kGy/s |
| ≥ 99.0 % saturation | 1.0 kGy/s |
| Max. dose per pulse for | |
| ≥ 99.5 % saturation | 4.5 mGy |
| ≥ 99.0 % saturation | 9.1 mGy |
Ranges of use
| Chamber voltage | ± (100 ... 400) V |
| Radiation quality | (15 ... 70) kV X-rays |
| Field size | (0.5 x 0.5) cm2 ... (40 x 40) cm2 |
| Temperature | (10 ... 40) °C |
| (50 ... 104) °F | |
| Humidity | (20 ... 80) %, max 20 g/m3 |
| Air pressure | (700 ... 1060) hPa |