Features
- Perturbation-free electron chamber
- Thin entrance window and waterproof protection cap
- Small-sized for high spatial resolution
- Sensitive volume 0.02 cm3, vented to air
- Radioactive check device (option)
The 34045 Advanced Markus chamber is the successor of the well-known classic Markus electron chamber, equipped with a wide guard ring for perturbation-free measurements. 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 acc. IEC 60731 |
|---|---|
| Application | absolute dosimetry in high-energy electron beams |
| Measuring quantity | absorbed dose to water |
| Reference radiation quality | 60Co |
| Nominal sensitive volume | 0.02 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 | 0.67 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 | ≤ 1 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/cm3, 1.3 mm (protection cap included) |
| Water-equivalent window thickness |
1.06 mm (protection cap included) |
| Sensitive volume | radius 2.5 mm depth 1 mm |
| Guard ring width | 2 mm |
Ion collection efficiency at nominal voltage
| Ion collection time | 22 µs |
|---|---|
| Max. dose rate for ≥ 99.5 % saturation ≥ 99.0 % saturation |
187 Gy/s 375 Gy/s |
| Max. dose per pulse for ≥ 99.5 % saturation ≥ 99.0 % saturation |
2.78 mGy 5.56 mGy |
Useful Ranges
| Chamber voltage | ± (50 … 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
TN34045 Advanced Markus electron chamber, 0.02 cm3, connecting system BNT
TW34045 Advanced Markus electron chamber, 0.02 cm3, connecting system TNC
TM34045 Advanced Markus electron chamber, 0.02 cm3, connecting system M
Image Gallery
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