Orientation effects of ESR analysis of alanine-polymer dosimeters

Dosimetry for electron Intra-Operative RadioTherapy: Comparison of output factors obtained through alanine/EPR pellets, ionization chamber and Monte Carlo-GEANT4 simulations for IORT mobile dedicate accelerator

“…The peak-to-peak amplitude (h pp ) of the central line was used as a measure of the signal intensity and was chosen in accordance with different authors [38,39]. As the EPR signal intensity could vary with orientation of the pellet inside the cavity, as reported in literature [40], spectra were recorded at four different orientations with respect to the cylindrical axis of the tube. The standard alanine read-out process consists in four readings for each sample.…”

Response of l-alanine and 2-methylalanine minidosimeters for K-Band (24GHz) EPR dosimetry

“…The lock-in amplifier time constant was 500 ms. To correct for an eventual spectrometer instability, CaO(Mn 2+ ) was used as a reference sample [37]. To minimize orientation effects inside the resonance cavity, for each minidosimeter, three EPR spectra were recorded in different azimuthal orientations [38]. All spectra were recorded at room temperature.…”

Angular response of alanine samples: From powder to pellet

“…These methodologies were accepted in order to obtain reduced uncertainties by calculation of a mean because the anisotropy (sinusoidal) of the sample is intrinsic with a periodic angular response of (Weil et al, 1994). In addition, an angular response resulting from the manufacturing process of alanine pellets is experimentally observed (Feaugas-Leberre, 1999;Kojima et al, 1995). The type A uncertainty is calculated finally from the mean value and its standard deviation for pellets constituting the dosimeter.…”