EDGE Detector™ characterizes penumbra more precisely and with less averaging than ion chambers, making it the preferred detector for small field beam modeling and QA.

Waterproof and highly accurate, it works with all common water phantoms for SRS and IMRT beam modeling and TPS commissioning.

Well-Suited for Small Fields
EDGE Detector is comprised of a SunPoint® Diode Detector that is 842 times smaller, and has 100 times more signal, than micro ionization chambers. Its small size makes it ideal for accurate penumbra characterization and steep gradients for fields ≤10 cm.

Maintain Compliance
EDGE Detector supports compliance with TRS483 and precision dosimetry.

The graph above depicts output factors measured for CyberKnife® beams at Dmax (6 MV). The EDGE Detector agrees with EBT film, even for a 5 mm cone, whereas ion chambers underestimate the output factors of the small beams.

The graph above depicts PDD curves measured by different detectors for a 2 x 2 cm field (6 MV). The PDD curve measured by EDGE Detector agrees with those of the ion chambers.

"The practical methods described can be used for commissioning an SRS system with small cones. New correction factors significantly improve agreement between different detectors."

  • E. Lief, et al
  • Measurement of Output and Percent Depth Dose (PDD) for Small Stereotactic Radiosurgery (SRS) Cones Using Semiconductor and Microdiamond Detectors

Add this detector to your small field toolkit.


Device Specifications

Active Detection Area (mm)

0.8 x 0.8
0.3 from top
4.72 from end

Diode Die Location (mm)

2.7 from side; location is indicated by cross hairs on top of the housing

Water Depth Equivalent (mm)


Housing Wall Thickness (mm)

0.13 brass

External Dimensions (mm)

3.8 x 5.5 x 38

Nominal Sensitivity (nC/Gy)


Impedance (Mohm)

>200 at 10 mV reverse bias

Output Polarity



3.4 mm dia. x 1.8 m long, triax

Cable Connector

BNC or TNC triax, or adapters upon request