  The widespread diffusion of precision radiotherapy techniques, geared toward
the release of larger dose gradients in shorter time frames, is leading to new
challenges in dosimetry. Accurate dose measurements are essential to check for
beam anomalies and inaccuracies to ensure treatment efficacy and patient safety
during radiotherapy. This work describes the main features of a diamond
dosimeter coupled to an extremely compact front-end electronics. The detection
system was tested under the X-ray pulses generated by a medical LINAC for both
the 6 MV and the 18 MV accelerating voltages. Located in the LINAC's bunker, it
eliminates the need for a long cable connection between the detector and the
electronics, detrimental for the system response speed. Signal acquisition was
performed synchronously with the impinging X-ray pulses with a sampling period
as low as 20 us, allowing for a real-time beam monitoring. The dosimeter
demonstrated a very good stability despite the high value of the absorbed dose
during the performed experiments (about 100 Gy). The measured dose-per-pulse
values of 278 uGy and 556 uGy at 6 MV and 18 MV, respectively, are in excellent
agreement with the nominal values expected for the LINAC apparatus used for the
tests. In addition to single-pulse measurements, fundamental for dynamic
radiotherapy, the proposed system also allows for the calculation of both the
total collected charge and the photocurrent generated by the detector. In this
regards, despite the compactness, it demonstrates its effectiveness as a tool
for source diagnostics in terms of both beam intensity and emission timing.
