Detection of fluorescent low-energy proton tracks in lithium fluoride crystals

• Published in: Radiation measurements 2024-06, Vol.174, p.107140, Article 107140
• Main Authors: Piccinini, Massimo, Nichelatti, Enrico, Esposito, Giuseppe, Cisbani, Evaristo, Santavenere, Fabio, Anello, Pasqualino, Nigro, Valentina, Vincenti, Maria Aurora, Limosani, Francesca, Ronsivalle, Concetta, Ampollini, Alessandro, De Angelis, Cinzia, Montereali, Rosa Maria
• Format: Article
• Language: English
• Subjects: Bragg peak; Color centers; Fluorescent nuclear track detectors; Lithium fluoride; Radiophotoluminescence
• ISSN: 1350-4487; 1879-0925
• DOI: 10.1016/j.radmeas.2024.107140

The exploitation of visible radiophotoluminescence in lithium fluoride (LiF) crystals, due to local aggregate point defects produced by ionizing radiation in the crystal lattice, is demonstrated for fluorescent imaging of single tracks of protons at low energies. LiF crystals were irradiated perpendicularly with respect to nearly monochromatic, collimated proton beams at the energies of about 1 MeV in a fluence range from ∼5.8 × 105 p/cm2 up to ∼3.4 × 107 p/cm2 and of about 2.6 MeV in a fluence range from ∼9.6 × 105 p/cm2 up to ∼4.7 × 106 p/cm2. The fluence values were estimated by detecting and automatically counting the tracks on the images acquired with a fluorescence microscope at high magnification; they were found to be in agreement with those obtained using CR39 plastic detectors irradiated under the same experimental conditions. Despite the very short range in matter of these charged particles, by focusing the excitation blue light at discrete depths in the irradiated LiF crystals, an estimate of the proton energies was also obtained. These first results are encouraging for the utilization of LiF crystals as fluorescent nuclear track detectors under typical conditions employed in ion radiobiology. •Imaging of fluorescent tracks of 1 and 2.6 MeV protons in LiF crystals.•Proton beam energy estimated by fluorescent track image analysis at different depth.•Automatic counting of the tracks in the fluorescence images at high magnification.•Beam fluence of 1.4 × 106 p/cm2 in LiF in good agreement with that in CR39 detector.•Fluence in LiF crystals estimated up to 2.2 × 107 p/cm2 without track superposition.