Maggi, P.E. Carver, R.L. Hogstrom, H.R. Matthews II, K.L. JACoW Geneva, Switzerland 978-3-95450-180-9 10.18429/JACoW-NAPAC2016-TUPOA38 English 361-363 TUPOA38 ion electron linac detector real-time Contribution to a conference proceedings 2017 2017-01 http://dx.doi.org/10.18429/JACoW-NAPAC2016-TUPOA38 https://jacow.org/napac2016/papers/tupoa38.pdf Accelerator characterization and quality assurance is an integral part of electron linear accelerator (linac) use in a medical setting. The current clinical method for radia-tion metrology of electron beams (dose on central axis versus depth in water) only provides a surrogate for the underlying performance of the accelerator and does not provide direct information about the electron energy spectrum. We have developed an easy to use real-time magnetic electron energy spectrometer for characterizing the electron beams of medical linacs. Our spectrometer uses a 0.57 T permanent magnet block as the dispersive element and scintillating fibers coupled to a CCD camera as the position sensitive detector. The goal is to have a device capable of 0.12 MeV energy resolution (which corresponds to a range shift of 0.5 mm) with a minimum readout rate of 1 Hz, over an energy range of 5 to 25 MeV. This work describes the real-time spectrometer system, the detector response model, and the spectrum unfolding method. Measured energy spectra from multi-ple electron beams from an Elekta Infinity Linac are presented.