IBA Dosimetry Product Detectors

EFD 3G-pSi electron diode field detector

Based on the 3rd generation of pSi semiconductors. Since their introduction in 1992, the high doped p-type silicon detector chips, specifically designed for radiation therapy applications, have been the natural choice for measurements where high spatial resolution is required. The accuracy and lifetime of the diode detectors is unsurpassed in the field of radiation therapy today.

IBA Dosimetry Radiation Product EFD 3G PSI


PDD (Percentage Depth Dose) and TMR (Tissue Maximum Ratio) measurements in water are the most demanding relative measurements. Since both the dose rate and the energy spectra change with depth, the 3G-pSi detectors are designed to be independent of these parameters. 


EFD 3G-pSi

Electron beams, 4 to 25 MeV



Technical specs

EFD 3G-pSi electron diode field detector

  • Stem material: Stainless steel
  • Enclosure material: ABS and epoxy
  • Position of measurement point: Indicated by a cross-hair at the top of the detector
  • Effective measurement point (mm): 1.2 ± 0.2 from surface
  • Chip size (mm): 2.1 ˣ 2.1 ˣ 0.4
  • Active detector diameter (mm): 1.6
  • Active detector thickness (mm): 0.08


Operational characteristics for EFD 3G-pSi 

  • Typical sensitivity: 100 nC/Gy
  • Sensitivity decrease:  Co-60 < 1%/250 Gy ; 6 MV < 1%/250 Gy ; 15 MV < 1%/250 Gy
  • Dose rate linearity, conventional beams: < 1% in the range 0.1 - 0.6 mGy/pulse
  • Dose rate linearity, FFF beams: 3% at 1.0 mGy/pulse, 7% at 2.3 mGy/pulse
  • Sensitivity change with temperature: 0.25%/oC (typical)
  • Operating Voltage: 0 V
  • Waterproof: Yes
  • Polarity: Positive current on center connection


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