AbstractID: 7401 Title: Application of a Diamond Detector for Electron Beam Dosimetry
Applicability of a diamond detector for the measurement of electron beam depth dose has been investigated. The diamond detector
radiation response is independent of the incident beam energy. Compared to an ion chamber, the diamond detector possesses high
spatial resolution and radiation sensitivity. The measurements of electron beam depth dose distributions with diamond detector and an
ionization chamber are compared. AAPM TG-51 calibration protocol for high-energy photon and electron clinical beams requires that
the electron beam quality be specified in terms of R50, the depth in water of the 50% dose. R50 is calculated directly from I50, the depth
of 50% ionization corrected for gradient effects across the chamber volume. TG-51 also recommends that the depth ionization curves
be measured either with a small cylindrical chamber or with a plane parallel chamber. In order to convert the absorbed dose calibrated
at dref to dose at dmax, the depth ionization curve has to be converted to depth dose curve. This can be achieved by the methods given
in TG-25 and TG-51. A comparison of the central axis depth dose distributions measured directly by the PTW diamond detector and
calculated from Wllhofer IC 10 ion chamber ionization measurements for 6 - 21 MeV clinical electron beams from a Siemens KD2
linear accelerator indicates excellent agreement. The depth dose profiles measured by the two detectors are within + 1mm. Our
results indicate that a diamond detector can be conveniently used to determine both R50 and the central axis depth dose distributions.