PSI - Issue 47

Dionysios Linardatos et al. / Procedia Structural Integrity 47 (2023) 80–86 Linardatos/ Structural Integrity Procedia 00 (2023) 000 – 000

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* Corresponding author. Tel.: +30-210-5385-387 E-mail address: cmichail@uniwa.gr

1. Introduction In fields ranging from medical imaging to harsh-environments, industrial non-destructive testing (NDT), oil extraction facilities, etc., radiation converting materials are essential and their performance is of paramount importance, under various environmental conditions (Kandarakis, 2016; Mykhaylyk et al., 2019; Yanagida et al., 2013). In this sense, material selection should take into consideration the influence of important aspects such as radiation flux and temperature, on their light output performance (Bisong et al., 2019; Lebedev et al., 2019; Patri et al., 2019; Saxena, 2019). A material with enormous light yield (6x10 4 photons/MeV) and many advantages over conventional scintillating materials is cerium bromide (CeBr 3 ) (Loyd et al., 2020; Wei et al., 2014; Xie et al., 2020). This material has a short decay time of 19 ns, negligible afterglow (0.1 @ 3 ms), high atomic number (45.9 effective) and emission spectrum (emission peak at 380nm) adequate for coupling with many optical sensors. The properties of CeBr 3 are summarized in Table 1 (Koppert et al., 2019; Lecoq, 2016; Linardatos et al., 2022b, 2022a; van Loef and Shah, 2014). The drawbacks of this crystal are its fragility and hygroscopicity; thus encapsulation (Figure 1) is needed for protection from the environmental conditions (Advatech UK, 2022; Higgins et al., 2008). CaF 2 :Eu crystal is mechanically and thermally resistant. The crystal melts at 1087 ° C thus it can be adequately used in extreme environments (Chen, 2008; Cho et al., 2008; Dafinei et al., 2017; Dujardin et al., 2018; Eritenko and Tsvetyansky, 2020; Fan et al., 2018; Jagtap et al., 2019; Lecoq, 2016; Lecoq et al., 2017; Linardatos et al., 2022a; Michail et al., 2019; Saatsakis et al., 2020; van Eijk, 2002). In this study the temperature performance of CeBr 3 was measured in the range of 26 to 155 degrees Celsius, using X-rays, and compared with results of CaF 2 crystals for possible integration in medical imaging and harsh environments (Rutherford et al., 2016; Saatsakis et al., 2020).

Table 1. CeBr 3 and CaF 2 :Eu properties.

Properties

Units g/cm³

CeBr 3

CaF 2 :Eu

Density

5.1

3.18 16.5 1087

Atomic number (effective)

45.9 722

Melting point

°C

Coefficient of thermal expansion

° C -1 Mho

17.7 x 10 -6

19.5 x 10 -6

Mineral hardness

-

4

Maximum of emission

nm

380

435

Fig. 1. The CeBr 3 crystal within the encapsulation protection cover.