Evaluation of TL and OSL responses of CaF2:Tm for electron beam processing dosimetry

Author(s)

Asfora, Viviane K. ^[1] ; Antonio, Patricia L. ^[2] ; Goncalves, Josemary A. C. ^[2] ; Bueno, Carmen C. ^[2] ; Barros, Vinicius S. M. de ^[1] ; Oliveira, Charles N. P. ^[1] ; Caldas, Linda V. E. ^[2] ; Khoury, Helen J. ^[1]

Affiliation

^[1] Univ Fed Pernambuco DEN UFPE, Dept Energia Nucl, Recife, PE - Brazil

^[2] Comissao Nacl Energia Nucl IPEN CNEN SP, Inst Pesquisas Energet & Nucl, Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Radiation Measurements; v. 140, JAN 2021.
• Web of Science Citations: 0

Abstract

The thermoluminescence (TL) and infrared stimulated luminescence (IRSL) responses of in-house produced CaF2: Tm dosimeters are investigated in this work, envisaging their application in electron beam (EB) radiation processing. The irradiations were performed at an industrial EB accelerator (1.5 MeV) covering a dose rate range of 2-8 kGy/s and dose up to 10 kGy. In general, the TL glow curves display four peaks, termed as peaks 2, 3, 4, and 5, corresponding to temperatures at similar to 150, 200, 240, and 300 degrees C, respectively. The intensity of the low temperature peaks (2 and 3) grows with the dose, while the others remain constant (saturated). Nevertheless, an evident dose effect on the glow curves manifests in decreased peak3/peak2 ratio with increasing doses. The CW-IRSL curves exhibit similar patterns with an initial signal increase, followed by an exponential decay. Instead of the normal monotonic decays, these peak-shaped curves might be due to the charge capture competition between empty shallow traps and recombination centers. Both TL and IRSL intensities increase linearly with doses up to 6 kGy, and for higher doses, they become sub-linear with a saturation trend around 10 kGy. Another common feature of TL/IRSL response is its dose rate dependence, being more sensitive at higher dose rates. Despite being dose-rate dependent, the CaF2:Tm dosimeters might be suitable for EB processing dosimetry. However, for their use as routine dosimeters, relevant dosimetric characteristics, such as fading and response reproducibility, have to be investigated. Work in this direction is underway. (AU)

• FAPESP's process: 14/12732-9 - Determination of a reference system and a routine dosimeter using fototransferred luminescent techniques, for high-dose dosimetry in gamma irradiators
• Grantee: Patrícia de Lara Antonio
• Support Opportunities: Scholarships in Brazil - Post-Doctoral