Features
- Thin entrance window and waterproof protection cap
- Small-sized for high spatial resolution
- Sensitive volume 0.055 cm3, vented to air
- Radioactive check device (option)
The 23343 Markus chamber is manufactured in the original famous Markus design. Absorbed dose to water can be measured by applying correction factors for perturbation effects as published in pertinent dosimetry protocols. The thin entrance window allows measurements in solid state phantoms up to the surface. The protection cap makes the chamber waterproof for measurements in water phantoms.
Specifications
| Type of product | vented plane parallel ionization chamber |
|---|---|
| Application | absolute dosimetry in high-energy electron beams |
| Measuring quantity | absorbed dose to water |
| Reference radiation quality | 60Co |
| Nominal sensitive volume | 0.055 cm3 |
| Design |
waterproof with protection cap, vented |
| Reference point | in chamber center on entrance foil, or 1.3 mm below surface of protection cap |
| Direction of incidence | perpendicular to chamber plane |
| Nominal response | 2 nC/Gy |
| Long-term stability | ≤ 1 % per year |
| Chamber voltage | 300 V nominal ± 400 V maximal |
| Polarity effect | ≤ 1 % for electrons ≥ 9 MeV |
| Directional response in water | < ± 0.1 % for chamber tilting < ± 10° |
| Leakage current | ≤ ± 4 fA |
| Cable leakage | < 3.5 pC/(Gy·cm) |
Materials and measures
| Entrance foil | 0.03 mm PE (polyethylene CH2), 2.76 mg/cm2 |
|---|---|
| Protection cap | 0.87 mm PMMA, 1.19 g/cm3, 0.4 mm air |
| Total window area density | 106 mg/cm2, 1.3 mm (protection cap included) |
| Water-equivalent window thickness |
1.06 mm |
| Sensitive volume | radius 5.3 mm depth 2 mm |
| Guard ring width | < 0.2 mm |
Ion collection efficiency at nominal voltage
| Ion collection time | 90 µs |
|---|---|
| Max. dose rate for ≥ 99.5 % saturation ≥ 99.0 % saturation |
12 Gy/s 24 Gy/s |
| Max. dose per pulse for ≥ 99.5 % saturation ≥ 99.0 % saturation |
0.7 mGy 1.4 mGy |
Useful Ranges
| Chamber voltage | ± (100 … 300) V |
|---|---|
| Radiation quality | (2 … 45) MeV electrons |
| Field size | (3 x 3) 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
T48010 Radioactive check device 90Sr
T23343/11 Chamber holding device for check device
Parts
TN23343 Markus electron chamber 0.055 cm3, connecting system BNT
TW23343 Markus electron chamber 0.055 cm3, connecting system TNC
TM23343 Markus electron chamber 0.055 cm3, connecting system M
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