Comparison of EPR response of alanine and Gd2O3-alanine dosimeters exposed to TRIGA Mainz reactor

Marrale, Maurizio; Schmitz, T.; Gallo, Salvatore; Hampel, G.; Longo, A.; Panzeca, S.; Tranchina, Luigi

doi:10.1016/j.apradiso.2015.08.016

Cited by 20 publications

(6 citation statements)

References 27 publications

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“…A relevant case is boron neutron capture therapy (BNCT), where the characterization of the radiation field in a certain position of the facility, that implies the simultaneous determination of the photon dose and the thermal neutron fluence, is crucial to manage the appropriate settings for the BNCT therapy [27][28][29].Most efforts have been focused on studying the EPR dosimetric properties of 6 Li-enriched LiFo due to its better sensitivity and its ability to detect thermal neutrons. A dual dosimeter that would combine the simultaneous EPR readings of both natural Li and 6 Li-enriched LiFo pellets has been proposed in the past to characterize a mixed field of gamma photons and neutrons [26].…”

Section: Introductionmentioning

confidence: 99%

A dual natural lithium formate/L-alanine EPR dosimeter for a mixed radiation field in a boron neutron capture therapy irradiation facility

Alejandro

Longhino

Álvarez

et al. 2020

J. Phys. D: Appl. Phys.

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Standard commercial L-alanine pellets and specially prepared natural lithium formate monohydrate powder samples of specific granulometry were irradiated in a 60 Co gamma-ray irradiation plant and in the mixed field (thermal neutrons and gamma photons) of a boron neutron capture therapy (BNCT) experimental facility. The γ-doses applied with the 60 Co source range from 0.1 to 50 kGy, while those in the BNCT facility go from ~7 Gy to 150 Gy. The thermal neutron fluences range from 10 12 neutrons cm −2 to 2 10 13 neutrons cm −2 . The irradiation of materials promotes the creation of stable electronic defects (generally free radicals) which constitute paramagnetic centers that can be detected and quantified by electron paramagnetic resonance (EPR). After irradiation, the EPR characterization of the samples was performed by determining the EPR intensity of the spectrum relative to a reference standard constituted by Mn 2+ impurities diluted into a MgO single crystal. As expected, L-alanine has revealed to be largely insensitive to thermal neutrons fluence in the investigated range. On the contrary, it is shown that the EPR intensity of irradiated natural lithium formate monohydrate powders is clearly sensitive to thermal neutrons and has a linear dependence with the γ-dose. We propose a dual dosimeter by combining L-alanine pellets and formate powders that would allow to determine the γ-dose and thermal neutron fluence in a selected position of the BNCT irradiation facility. Moreover, we demonstrate that the 6 Li enrichment that has been proposed in the literature to enhance the performance of lithium-based EPR dosimeters is not crucial in our case. Instead, the natural isotopic abundance of lithium is large enough to obtain a satisfactory sensibility to thermal neutrons in our BNCT facility for fluencies >10 12 neutrons cm −2 .

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Section: Introductionmentioning

confidence: 99%

A dual natural lithium formate/L-alanine EPR dosimeter for a mixed radiation field in a boron neutron capture therapy irradiation facility

Alejandro

Longhino

Álvarez

et al. 2020

J. Phys. D: Appl. Phys.

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“…Finally, the readout procedure is non-destructive, contrary to most luminescent detectors [21,26,[31][32][33][34]. In recent years, several studies have focused increasing the sensitivity of EPR dosimeters, reducing relaxation times and thus decreasing the microwave power saturation of the absorption line by adding high Z elements (such as silver, gold, rhodium, nickel, gadolinium) [3,7,23,[35][36][37][38][39][40].…”

Section: Introductionmentioning

confidence: 99%

Alanine films for EPR dosimetry of low-energy (1–30 keV) X-ray photons

D'Oca

Marrale

Abbene

et al. 2019

Nuclear Instruments and Methods in Physics Research Section B:

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L-α-alanine has aroused considerable interest for use in radiation EPR dosimetry and has been formally accepted as a secondary standard for high-dose (kGy) and transfer dosimetry of high-energy photons and electrons. In this work, we extended the investigation of the energy response of alanine EPR films in the low energy range for X-photons (1-30 keV). Electron Paramagnetic Spin Resonance (EPR) measurements were performed on Kodak BioMax alanine films exposed to low-energy X-rays from a Cu-, Wand Mo-targets tube operating at voltages up to 30 kV. Films were chosen because of the low penetration of the soft X-rays used. The response of alanine to low-energy X-rays was characterized experimentally and the relative response (with respect to high energy photons) was found to be between 0.8 and 0.9 for Cu-and Wtube X-rays, and 1.0 for Mo-tube X-rays. The attenuation profiles were investigated and it was found that 1 mm of film material reduces the intensity of the X-ray-beam by about 70%, 50% and 40% for Cu-, Wand Mo-tube X-rays, respectively. Monte Carlo simulations were performed to model the energy release as well as the depth dose profiles for the various radiation beams used. These data are considered relevant

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“…Among the var i ous dosimetric sys tems, there are di a mond de tec tors [3], ion iza tion cham bers [4][5][6], scin tilla tors [7], semi con duc tor de tec tors [8], ra dio-chro mic film [9], ESR do sim e ters [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], thermoluminescent do sim e ters (TLD) [25][26][27][28], and scin til la tion do sim e ters [29]. Of ten these dosimetric sys tems are aided by Monte Carlo sim u la tions that also pro vide many de tails on the par ti cle types and en ergy spec tra [17,30,31]. The re cent lit er a ture in cludes sev eral ex per i ments on Fricke gels aimed at op ti miz ing the rec ipe for in creas ing the sen si tivity to dose and/or the lo cal sta bil ity of the ra di a tion produced fer ric ions and ap pli ca tions for clin i cal beam dosim e try [32][33][34].…”

Section: Introductionmentioning

confidence: 99%

Preliminary magnetic resonance relaxometric analysis of Fricke gel dosimeters produced with polyvinyl alcohol and glutaraldehyde

Gallo

Collura

Iacoviello³

et al. 2017

NUCL TECH RAD PROT

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This work de scribes the pre lim i nary anal y sis of Fricke gels do sim e ters char ac ter ized by a new for mu la tion mak ing use of a ma trix of poly vi nyl al co hol cross-linked by add ing glutaraldehyde and an a lyzed by means of nu clear mag netic res o nance relaxometry. In pre vi ous op ti cal stud ies, these gels have shown prom is ing dosimetric fea tures in terms of pho ton sen si tiv ity and low diffu sion of fer ric ions pro duced af ter ir ra di a tion. In this work, we used a por ta ble nu clear mag netic res o nance relaxometer to mea sure the re laxation times (which are im por tant for dosimetric ap pli ca tions) of these gel ma te ri als. For this pur pose, we per formed a study for op ti miz ing the ac qui si tion pa ram e ters with a nu clear magnetic res o nance relaxometer. Gel sam ples were ex posed to clin i cal 6 MV pho tons in the dose range be tween 0 and 20 Gy. Nu clear mag netic res o nance relaxometry mea sure ments were performed and the sen si tiv ity to pho ton beams was mea sured for var i ous val ues of the Fe 2+ ion con cen tra tion. The anal y ses pointed out that the MR sig nal in creases as the Fe 2+ con tent increases and the in crease is about 75 % when the con cen tra tion of Fe 2+ ions is in creased from 0.5 mM to 2.5 mM. Fur ther more, the sen si tiv ity im prove ment achieved with in creas ing the Fe 2+ con cen tra tion is about 60 %. This pa per shows that the por ta ble nu clear mag netic res onance relaxometer used for anal y sis of po rous ma te ri als can be used for char ac ter iza tion of these dosimetric gels and this study can be con sid ered as the first step for the char ac ter iza tion of these do sim e ters which in fu ture could be used for 3-D dose map ping in clin i cal ap pli ca tions.

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Comparison of EPR response of alanine and Gd2O3-alanine dosimeters exposed to TRIGA Mainz reactor

Cited by 20 publications

References 27 publications

A dual natural lithium formate/L-alanine EPR dosimeter for a mixed radiation field in a boron neutron capture therapy irradiation facility

A dual natural lithium formate/L-alanine EPR dosimeter for a mixed radiation field in a boron neutron capture therapy irradiation facility

Alanine films for EPR dosimetry of low-energy (1–30 keV) X-ray photons

Preliminary magnetic resonance relaxometric analysis of Fricke gel dosimeters produced with polyvinyl alcohol and glutaraldehyde

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Comparison of EPR response of alanine and Gd2O3-alanine dosimeters exposed to TRIGA Mainz reactor

Cited by 20 publications

References 27 publications

A dual natural lithium formate/L-alanine EPR dosimeter for a mixed radiation field in a boron neutron capture therapy irradiation facility

A dual natural lithium formate/L-alanine EPR dosimeter for a mixed radiation field in a boron neutron capture therapy irradiation facility

Alanine films for EPR dosimetry of low-energy (1–30 keV) X-ray photons

Preliminary magnetic resonance relaxometric analysis of Fricke gel dosimeters produced with polyvinyl alcohol and glutaraldehyde

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Alanine films for EPR dosimetry of low-energy (1–30 keV) X-ray photons