Proton Beam Dosimetry: a Comparison between a Plastic Scintillator, Ionization Chamber and Faraday Cup

Abstract

In this study, a comparison was made between a plastic scintillator (BC400), a Faraday Cup (FC) and an ionization chamber (IC) used for routine proton dosimetry. Thin scintillators can be applied to proton dosimetry and consequently to proton therapy as relative dosimeters because of their water-equivalent nature, high energy-light conversion efficiency, low dimensions and good proportionality to the absorbed dose at low stopping powers. To employ such scintillators as relative dosimeters in proton therapy, the corrective factors must be applied to correct the quenching luminescence at the Bragg peak. A fine linear proportionality between the luminescence light yield Y and the proton flux in a thin (0.5 mm) scintillator for the 20 and 30 MeV proton beams were observed. The experimental peak/plateau ratios of Bragg Curve for 2, 1 and 0.5 mm scintillators with an accuracy of 0.5% were obtained to be 1.87, 1.91 and 2.30, respectively. With combination of the Markus chamber and the CR-39 detector, the peak/plateau ratio was improved to 3.26. The obtained data of the luminescence yield as a function of the specific energy loss is in agreement with the Craun-Birk's theory. Results show that the FC and Markus ionization chamber are in agreement within 4%, while the FC gives a lower dose evaluation. For a defined beam, the data for the fluence measurements are reproducible within a good accuracy.

Characterization of the exradin W1 plastic scintillation detector for small field applications in proton therapy

“…Excellent reviews of PSDs for radiotherapy applications have been published (Beddar et al 1992a, 1992b, 1992cBeaulieu and Beddar 2016. Additionally, PSD utility in proton therapy has been explored (Ghergherehchi 2010, Alsanea et al 2018 with some early studies into the W1 (Alsanea 2015. The primary difficulty with using PSDs, such as the W1, Characterization of the exradin W1 plastic scintillation detector for small field applications in proton therapy in x-ray, electron or gamma beams is the parasitic Čerenkov light signal generated when energetic electrons travel faster than the speed of light in the medium (Čerenkov 1937(Čerenkov , Beddar et al 1992a.…”

Polyethylene Naphthalate Scintillator: A Novel Detector for the Dosimetry of Radioactive Ophthalmic Applicators

“…Thus, our recent investigations indicate that there is no or only a small quenching effect in PEN. This absence of a distinct quenching effect for low-energy photons makes PEN also an interesting material for further investigations as a detector, for instance for the dosimetry of therapeutic proton beams [38,39]. …”

Introducing a Novel Beta-ray Detector Based on Polycarbonate/ Bismuth Oxide Nanocomposite: Simulation and Experiment

“…Several pure betaemitters are 3 H (18.6 keV), 14 C (156 keV), 32 P (1.71 MeV), 33 P (248 keV), 35 S (167 keV), 36 Cl (714 keV), 345 Ca (252 keV), 63 Ni (67 keV), 90 Sr/ 90 Y (546 keV/2.27 MeV), 147 Pm (224 keV), and 204 Tl (766 keV) [22].Various types of scintillators are commonly used to detect beta-rays. In addition, low Z materials including organic polymers are excellent absorbers of charged particles such as beta-rays, which will provide high sensitivity for charged particle detection [20,[23][24][25][26]. A disadvantage of some scintillators and gas-ow type proportional counters is limitations due to their hygroscopicity, and scalability [26].…”