Cylindrical Reference Chamber 23361

Vented sensitive volume of 30 cm³
Suitable as high precision reference chamber for radiation protection dosimetry
Very flat energy response within a wide range

The cylindrical stem chamber has been designed as a reference chamber for absolute dosimetry to be used by secondary standard dosimetry laboratories (SSDL) and users with high quality requirements. It has very small variations of response with radiation quality from low X-ray energies up to high-energy photon radiation.

The guard ring is designed up to the sensitive volume.

The chamber is constructed with a long rigid stem of approx. 20 cm length for easy mounting in the radiation beam. An acrylic build-up cap with 3 mm wall thickness for in-air measurement in 60Co beams is included with each chamber, as well as a calibration certifiate.

Air density correction is required for each measurement. A radioactive check device with an appropriate holder is optionally available.

Type of product	vented cylindrical
	ionization chamber
Application	radiation protection measurement
Measuring quantities	air kerma, photon equivalent dose, exposure
Design	not waterproof, vented
Nominal sensitive volume	30 cm³
Reference point	on chamber axis, 27 mm from chamber tip
Direction of incidence	radial
Nominal response	1 μC/Gy
Chamber voltage	400 V nominal, ± 500 V maximal
Energy response	≤ ± 4 % (40 keV ... 60Co)
Directional response in air	≤ ± 0.5 % for rotation around the chamber axis,
Leakage current	≤ ± 10 fA
Stem leakage	≤ 1 pC/(Gy·cm)

Materials and measures

Wall of sensitive volume	1 mm PMMA, graphited
Total wall area density	119 mg/cm2
Dimension of sensitive volume	radius 15.5 mm, length 51 mm
Central electrode	graphite coated Al
	diameter 14 mm
Outer dimensions	diameter 33 mm
	length 335 mm
Build-up cap	PMMA, thickness 3 mm

Ion collection efficiency at nominal voltage

Ion collection time	1.3 ms
Max. dose rate for
≥ 99.5 % saturation	60 mGy/s
≥ 90.0 % saturation	120 mGy/s
Max. dose per pulse for
≥ 99.5 % saturation	50 μGy
≥ 99.0 % saturation	100 μGy

Ranges of use

Radiation quality	30 keV ... 50 MeV
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

T23237 Chamber holding device for check device