UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2026-06-11 23:58
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Conference: Bucharest University Faculty of Physics 2026 Meeting


Section: Nuclear and Elementary Particles Physics


Title:
Energy Measurements in Electron and Proton Beams Using Gafchromic Films


Authors:
Maria BOBOACA (1), Delia Magdalena DINU (1), Mihaela PARVU (1), Radu Alin VASILACHE (1)


Affiliation:
1) Physics Faculty, University of Bucharest


E-mail
radu-alin.vasilache@g.unibuc.ro


Keywords:
Energy measurements, charged particle beams, FLASH therapy


Abstract:
The last years have seen a marked increase in the interest for FLASH radiotherapy and, as such, a significant number of radiobiology studies have been performed [1]. All these studies have in common one thing: the need for accurate in-beam dosimetry [2] and, as such, the need for accurate energy measurement. Some of these studies have been designed and performed at ELI-NP where, due to the very short time of the pulses, the traditional energy measurement methods (like, for instance, PDD measurement with a water phantom) cannot be applied. One way to measure the energy is to use stacks of radiochromic films, like Gafchromic. This method has some limitations: the resolution is limited by the dead layer of the films and, as such, may pose some significant problems especially when used in low energy proton beams or other high LET particle beams. One way around this problem is to position the film in axial presentation (i.e place it parallel to the beam axis). We used this technique to measure electron energies in 5 MeV and 10 MeV electron beams and in a proton beam with a nominal energy of 17 MeV. The electron beams were generated by a medical LINAC (Siemens Primus, from Colțea Clinical Hospital) whilst the proton beam was generated by the TR19 cyclotron from NIPNE-HH. In both cases, the energy was measured not only at 0 degrees (i.e film parallel with the beam axis) but also at angles between 1 and 5 degrees between the film surface (and thus the active layer, too) and the beam axis, in order to evaluate the errors due to misalignement. We will present the results of these measurements and compare the misalignement errors with the homogeneity of the beams.


References:

1. M. Straticiuc et al., New setup for basic radiobiology studies using a 3 MV TandetronTM: Design and developments, Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 528:45 - 53

DOI: 10.1016/j.nimb.2022.08.001

2. R. A. Vasilache et. al, A Prototype Detector Array for Measurements in Laser Accelerated Charged Particle Beams, Journal of Physics Conference Series 1643(1)

DOI: 10.1088/1742-6596/1643/1/012042

Acknowledgement:
The authors would like to acknowledge the support given by Daniuela Stroe from Colțea Clinical Hospital and Mihai Straticiuc and Liviu Crăciun from NIPNE-HH during the measurements performed for this paper