PPC40 Plane Parallel Chamber

Description

The parallel plate ionization chamber PPC40 is designed for absolute and relative electron beam dosimetry above 2 MeV in the measuring quantity absorbed dose to water. It can be used for proton beam absolute and relative dosimetry and for photon beam depth-dose measurements as well. The PPC40 is entirely made from PMMA; with graphitized electrodes. It is constructed with a circular sensitive volume of planar geometry covered by a rigid 1 mm thick entrance window. As an associated measuring instrument for precise absolute dose determinations, in reference dosimetry, compliance testing or installation and set-up of treatment machines or other equipment, it is recommended to use the reference-class therapy dosimeter Dose1. The PPC40 is waterproof and its cable is covered by a watertight silicon sleeve that allows for air ventilation.


Technical specs

Outer dimensions

  • Chamber outer diameter: 44.0 mm
  • Chamber body height: 10.0 mm
  • Stem diameter: 10.0 mm
  • Stem length: 50.0 mm

Inner dimensions

  • Sensitive volume (nominal): 0.40 cm3
  • Cylinder height: 2.0 mm
  • Entrance window (polarizing electrode) diameter: 20.0 mm
  • Entrance window thickness: 1.0 mm
  • Diameter of collecting electrode: 16.0 mm
  • Guard ring diameter: 17.8 mm
  • Guard ring width: 3.4 mm

 

Operational characteristics

  • Polarizing voltage: ±300 V (max. ±500 V)
  • Typical leakage current: 5 fA
  • Recommended pre-irradiation: 5 Gy
  • Typical sensitivity: 11 nC/Gy
  • Guard potential: ±300 V (max. ±500 V)
  • Temperature range: 15 to 35 °C
  • Relative humidity range: 20 % to 80 %