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.

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