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PTW 31010, 0.125cc Semiflex Chamber

PTW 31010, 0.125cc Semiflex Chamber
PTW 31010, 0.125cc Semiflex Chamber

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PTW 31010, 0.125cc Semiflex Chamber.


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PTW 31010, 0.125cc Semiflex Chamber.

Waterproof thimble chambers for measuring high-energy photon and electron radiation.

The semiflex chambers are designed for therapy dosimetry, mainly for dose distribution measurements in motorized water phantoms.  They have a short stem for mounting and a flexible connection cable.  The nominal useful energy range is from 30 kV to 50 MV photons and 6 MeV to 50 MeV electrons.  The wall material is graphite with a protective acrylic cover.  The guard rings are designed up to the measuring volume.  An acrylic build-up cap for in air measurement in 60Co beams is included with each chamber, as well as a calibration certificate for calibration in absorbed dose to water or in air kerma.  Air density correction is required for each measurement.  Both chambers are shaped cylindrically with an inner diameter of 5.5 mm; they differ only in the length of the measuring volume.

• Vented sensitive volumes of 0.125 cm3 and 0.3 cm3

• Suitable for use in water phantoms

• Flat energy response within a wide energy range

The Model 31010, 0.125 cm3 chamber is ideal for 3D dosimetry in a water phantom, since the measuring volume is approximately spherical resulting in a flat angular response over an angle of ± 160° and a uniform spatial resolution along all three axes of a water phantom.  This chamber has a 31 mm rigid stem for mounting.

Type of Product:  vented cylindrical ionization chamber
Application:  absolute dosimetry in radiotherapy beams
Measuring Quantities:  absorbed dose to water, air kerma, exposure
Reference Radiation Quality:  60Co
Nominal Sensitive Volume:  0.125 cm3
Design:  Waterproof, vented fully guarded
Reference Point:  on chamber axis, 4.5 mm from chamber tip
Direction of Incidence:  radial
Nominal Response:  3.3 nC/Gy
Long-term Stability:  ≤ 1% per year
Chamber Voltage:  400 V nominal ±500 V maximal
Polarity Effect at 60Co:  < 1%
Photon Energy Response:  ≤ ± 2% (140 kV to 280 kV),  ≤ ± 4% (140 kV to 60Co)
Directional Response in Water:  ≤± 0.5 % for rotation around the chamber axis and for tilting of the axis up to ± 10°
Leakage Current:  ≤ ± 4 fA
Cable Leakage:  ≤ 1 pC/(Gy∙cm)

Materials and Measures: 
Wall of Sensitive Volume:  0.55 mm PMMA 1.19 g/cm3, 0.15 mm graphite 0.82 g/cm3

Total Wall Area Density:  78 mg/cm2
Dimension of Sensitive Volume:  radius 2.75 mm, length 6.5 mm
Central Electrode:  Al 99.98, diameter 1.1 mm
Build-up Cap:  PMMA, thickness 3 mm

Ion Collection Efficiency at Nominal Voltage: 
Ion collection time:  100 µs

Max. dose rate for:
> 99.5 % saturation:
  6 Gy/s
> 99.0 % saturation:  12 Gy/s

Max. dose per pulse for:
> 99.5 % saturation:
  0.5 mGy
> 99.0 % saturation:  1.0 mGy

Useful ranges: 
Chamber voltage:  ±100 to 400 V
Radiation quality:  66 kV to 50 MV photons (10 to 45) MeV electrons (50 to 270) MeV protons
Field size:  3 x 3 cm2 to 40 x 40 cm2
Temperature:  50° - 104° F (10° - 40°C)
Humidity:  10 - 80 %, max 20 g/m3
Air pressure:  700 - 1060 hPa


 Please specify which connection end is needed

Data Sheet


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