Soft X-Ray Chamber 23342
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
- Sensitive volume 0.02 cm3, vented
The 23342 soft X-Ray chamber is the golden standard for reference dose measurements in low-energy photon beams as used in superficial radiation therapy.
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 acc. IEC 60731 |
| 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 | 0.02 cm3 |
| Nominal response | 1 pC/Gy |
| Long-term stability | ≤ 1 % per year |
| Chamber voltage | 300 V nominal |
| ± 500 V maximal | |
| Reference point | inner surface of the entrance window, at the center of the window |
| 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 2.55 mm |
| depth 1 mm | |
| Electrode | radius 1.5 mm |
Ion collection efficiency at nominal voltage
| Ion collection time | 22 μs |
| Max. dose rate for | |
| ≥ 99.5 % saturation | 188 kGy/s |
| ≥ 99.0 % saturation | 375 kGy/s |
| Max. dose per pulse for | |
| ≥ 99.5 % saturation | 2.8 mGy |
| ≥ 99.0 % saturation | 5.6 mGy |
Ranges of use
| Chamber voltage | ± (100 ... 400) V |
| Radiation quality | (15 ... 70) kV X-rays |
| Field size | (1 x 1) cm2 ... (40 x 40) cm2 |
| Temperature | (10 ... 40) °C |
| (50 ... 104) °F | |
| Humidity | (20 ... 80) %, max 20 g/m3 |
| Air pressure | (700 ... 1060) hPa |
Options
| T48010 | Radioactive check device 90Sr |
| T23238 | Chamber holding device for check device |