Features
- Pencil type chamber for measurements within a CT head or body phantom or in air
- Provides a sensitive measuring length of 10 cm
- Shows a homogeneous response over the whole chamber length
The CT chamber type 30009 is a vented cylinder chamber designed for measurements of photon radiation in computed tomography. The typical measuring quantity is dose length product, which allows the determination of the CTDI1 and CTDIW2 according to IEC 61223-2-6
Specifications
| Type of product | vented pencil type chamber |
|---|---|
| Application | dosimetry in computed tomography |
| Measuring quantities | air kerma length product, exposure length product |
| Reference radiation quality | 120 kV, HVL 5.00 mm Al (RQR9) |
| Nominal sensitive volume |
3.14 cm3 |
| Design | not waterproof, vented, pencil type |
| Reference point | chamber center |
| Direction of incidence | radial |
| Nominal response | 14 nC/Gy |
| Chamber voltage |
100 V nominal ± 500 V maximal high voltage to be connected only with active current-limiting device (Imax < 0.5 mA) |
| Energy response | ≤ ± 3 % (70 … 150) kV |
| Directional response | ≤ ± 2 % for tilting < ± 170° |
| Leakage current | ≤ ± 10 fA |
| Cable leakage | ≤ 1 pC/(Gy·cm) |
Materials and measures
| Wall material | 1 mm PMMA, graphite coated |
|---|---|
| Wall area density | 120 mg/cm2 |
| Dimension of sensitive volume |
radius 7 mm length 100 mm |
| Electrode | Al tube, outer diameter 3 mm, inner diameter 2 mm |
Ion collection efficiency at nominal voltage
| Ion collection time |
300 µs |
|---|---|
| Max. dose rate for ≥ 99.5 % saturation ≥ 99.0 % saturation |
0.9 Gy/s |
| Max. dose per pulse for ≥ 99.5 % saturation ≥ 99.0 % saturation |
0.14 mGy |
Useful Ranges
| Chamber voltage | ± (100 … 400) V |
|---|---|
| Radiation quality | (70 … 150) kV |
| Temperature | (10 … 40) °C (50 … 104) °F |
| Humidity | (10 … 80) %, max 20 g/m3 |
| Air pressure | (700 … 1060) hPa |
Parts
TN30009 CT chamber 3.14 cm3, connecting system BNT
TW30009 CT chamber 3.14 cm3, connecting system TNC
TM30009 CT chamber 3.14 cm3, connecting system M
- CTDI = Computed Tomography Dose Index
- CTDIW = Weighted Computed Tomography Dose Index
- Both definitions acc. IEC 60601-2-44
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