- Email: [email protected]
Comparative study of dosimeter properties between Al2O3 transparent ceramic and single crystal
Accepted Manuscript Comparative study of dosimeter properties between Al2O3 transparent ceramic and single crystal Takumi Kato, Naoki Kawano, Go Okada, Noriaki Kawaguchi, Takayuki Yanagida PII:
S1350-4487(17)30403-1
DOI:
10.1016/j.radmeas.2017.09.006
Reference:
RM 5838
To appear in:
Radiation Measurements
Received Date: 10 June 2017 Revised Date:
1 September 2017
Accepted Date: 20 September 2017
Please cite this article as: Kato, T., Kawano, N., Okada, G., Kawaguchi, N., Yanagida, T., Comparative study of dosimeter properties between Al2O3 transparent ceramic and single crystal, Radiation Measurements (2017), doi: 10.1016/j.radmeas.2017.09.006. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Comparative Study of Dosimeter Properties between Al2O3 Transparent Ceramic and Single Crystal Takumi Kato, Naoki Kawano, Go Okada, Noriaki Kawaguchi and Takayuki Yanagida
RI PT
Nara Institute of Science and Technology (NAIST) 8916-5 Takayama-cho, Ikoma-shi, Nara 630-0192, Japan Phone:+81-743-72-6144 Email: [email protected] Abstract
We have synthesized the Al2O3 transparent ceramic by using spark plasma sintering (SPS) and investigated the dosimeter and scintillation properties for X-ray detections, in comparison with the
SC
single crystal. Under X-ray irradiation, emissions at 300, 400 and 693 nm were observed in both the samples. To identify the origins of these emissions, scintillation decay times were investigated. Based on the results, emissions at 300, 400 and 693 nm are attributed to F+ centers, F centers and
M AN U
Cr3+ impurity ions, respectively. The thermally-stimulated luminescence (TSL) glow curves of both the samples showed a main peak around 50 °C. In addition, glow peaks were observed at 190, 290 and 360 °C. The TSL spectra had broad emission bands in the 300, 400 and 693 nm, which approximately agreed with the scintillation spectra. The TSL response was confirmed to be linear to the irradiation dose for transparent ceramic over the dose range from 0.3 to 1000 mGy while the
mGy.
TE D
sensitivity of the single crystal was lower and the response range confirmed was from 30 to 1000
AC C
EP
Keywords: transparent ceramic, Al2O3, scintillator, dosimeter
ACCEPTED MANUSCRIPT
1. Introduction Phosphors are used as radiation dosimeters for personal and environmental monitoring and in imaging plates and neutron detection for computed radiography (Boukhair et a., 2001; Bukur and Goksu,
RI PT
1998; Miyamoto et al., 2011; Zimmerman, 1971). These materials have a function to store and accumulate absorbed energy of ionizing radiation as a form of trapped electrons and holes. The electrons and holes are stored at localized trapping centers, and they recombine to emit light after de-trapping process by additional stimulation. Dosimeters based on phosphors are mainly divided into three types by different emission mechanisms. One is thermally-stimulated luminescence (TSL), which is observed by
SC
recombination of electrons and holes de-trapped from trapping centers by heat stimulation. Another is optically-stimulated luminescence (OSL) in which the stimulation is performed by light, instead of heat in TSL. The last one is radio-photoluminescence (RPL) which is a creation of new photoluminescence (PL)
M AN U
centers via interactions with ionizing radiation. Example materials used in practice today are Ti and Mg doped LiF single crystal (Zimmerman, 1971) for TSL, BeO ceramic (Bukur and Goksu, 1998) for OSL, and Ag-doped phosphate glass (Miyamoto et al., 2011) for RPL. Required properties for personal dosimetries are, for example, that the effective atomic number (Zeff) of dosimeter material is close to that of soft human body tissue (Zeff = 7.51) and that the dosimeter response monotonically increases with the incident radiation dose. In addition to the dosimeter properties, phosphors often show scintillation, which
TE D
is defined as an immediate luminescence upon radiation exposure without any additional stimulation. Scintillators are utilized in various different fields such as medicine (eg. X-ray computed tomography, PET, flat panel detector), security (eg. luggage inspection system), environmental monitoring and basic science (Itoh et al., 2007; Yamaoka et al., 2005; Yamagida et al., 2010; Totsuka et al., 2011). Recently, it was pointed out that a complementary behavior was observed between dosimeter and scintillator
EP
properties (Yanagida et al., 2014b; Yanagida, 2016); therefore, it is important to investigate both dosimeter and scintillation properties in order to comprehensively understand luminescence mechanisms
AC C
induced by ionizing radiation.
Aluminum oxide (Al2O3) was one of the classical materials studied for its possible application as a
radiation dosimeter, owing to its superior thermal stability, chemical stability and low effective atomic number close to the human body. Today, Al2O3 doped with carbon (Al2O3:C) crystals as TSL and OSL dosimeters are now well established in personal dosimetry, having been already commercially available for almost two decades (Alselrod et al., 2002; Alselrod et al., 1999; Colyott et al., 1996; McKeever et a., 1996; McKeever et al., 1999; McKever, 2011; ). Carbon ions are included to enhance defect creation as main emissions of Al2O3 are caused by several defects. On the other hand, with advancement of ceramic fabrication techniques, transparent ceramic of Al2O3 was reported (Coble, 1961; Jiang et al., 2008; Kim et al., 2009; Liu et al., 2014; Liu et al., 2013; Penilla et al., 2013; Roussel et al., 2013). However, no reports can be found about radiation responses of Al2O3 transparent ceramic material. Compared with single
ACCEPTED MANUSCRIPT
crystals, ceramic dosimeters are considered to have many advantages for a large number of defect centers included which enhance the dosimetric properties (Kato et al., 2016a; Nakamura, 2017c). In addition, ceramic materials are mechanically strong, flexibly prepared in a geometric shape of preference and cost effective.
RI PT
In this paper, we prepared Al2O3 transparent ceramics by the spark plasm sintering (SPS) method, and we investigated the dosimeter properties in comparison with the single crystal. In addition, we also studied their optical and scintillation properties in order to discuss the experimental results comprehensively. Radiation response properties of transparent ceramic are expected to be superior to those of single crystal since, in general, a larger number of defects are generated in transparent ceramic by
SC
the SPS method than those of single crystal. By using the SPS method, we have developed phosphor materials showing enhanced dosimeter and scintillator properties (Kato et al., 2016a; Kato et al., 2016b;
Nakamura et al., 2017c; Okada et al., 2016).
2. Experiment
M AN U
Kato et al., 2016c; Kato et al., 2016d; Kato et al., 2017; Nakamura et al., 2017a; Nakamura et al., 2017b;
Al2O3 transparent ceramic samples were synthesized by the SPS method using Sinter Land LabX-100. Here, a reagent grade of Al2O3 (99.99 %) powder was loaded in a graphite die and sandwiched between
TE D
two graphite punches. The sintering was carried out in three steps. First, the temperature was elevated from 25 °C to 600 °C within 5 min. Next, the temperature was slowly increased from 600 °C to 850 °C at a rate of 10 °C/min and held for 10 min while applying a pressure of 70 MPa. Finally, the temperature was further increased from 850 °C to 1300 °C at the rate of 10 °C/min and kept at 1300 °C for 20 min while applying 70 MPa pressure. After the synthesis, the wide surfaces of the obtained sample were
EP
mechanically polished with a polishing machine (MetaServ 250, BUEHLER). For comparison purposes, we purchased a single crystal from Neotron Co. Ltd. The single crystal was synthesized by the
AC C
Czochralski method.
Optical in-line transmittance spectra were evaluated by a spectrometer (V670, JASCO) over the spectral range of 190–2700 nm with 1 nm steps. In order to assign origins of emission centers, X-ray induced scintillation properties were measured. First, scintillation spectra were measured using our labconstructed setup. A sample was irradiated by X-rays generated from an X-ray tube in which the applied tube voltage and current were 40 kV and 5.2 mA, respectively. The scintillation emission was guided to a CCD-based spectrometer (Andor DU-420-BU2 or Ocean Optics QEPro depending on the spectral range) to measure the spectrum. Details of the setup was described previously (Yanagida et al., 2013b). Second, the scintillation lifetime by X-ray irradiation was measured using an afterglow characterization system equipped with a pulse X-ray tube (Yanagida et al., 2014a). The system is commercially available from Hamamatsu as a custom-ordered instrument. The applied voltage to the pulse X-ray source was 30 kV,
ACCEPTED MANUSCRIPT
and the system offers the time resolution of ~1 ns. In order to study the properties of Al2O3 transparent ceramic as a TSL dosimeter device, we have measured a TSL glow curve using a Nanogray TL-2000 (Yanagida et al., 2013a) after X-ray irradiations with various doses from 0.1 mGy to 1000 mGy. The heating rate was fixed to 1 °C/s for all the glow
RI PT
curve measurements, and the measurement temperature range was from 50 to 490 °C. Further, TSL spectrum was measured using the CCD-based spectrometer (QE Pro, Ocean Optics) while the sample was heated by an electric heater (SCR-SHQ-A, Sakaguchi E.H Voc) at a constant temperature.
SC
3. Results and discussion 3. 1 Sample
Fig. 1 shows Al2O3 transparent ceramic and single crystal samples used in this research. The
M AN U
thicknesses of the transparent ceramic and crystal samples were 0.59 and 1.00 mm, respectively. Since we polished the ceramic sample by hands, it was difficult to control the thickness precisely. Transparency of the ceramic sample was reasonably high that the black stripe patterns on the back was clearly seen. Fig. 2 shows the in-line transmittance spectra of the Al2O3 transparent ceramic and single crystal. The single crystal showed very high transmittance (80–85%) in the visible range, and the fundamental absorption edge was beyond the measurable range by the instrument. On the other hand, transmittance of the
TE D
transparent ceramic was much lower and varied 5–40% in the visible range. No particular absorption bands due to unexpected contamination were observed in both samples.
3. 2 Scintillation properties
EP
Fig. 3 represents X-ray induced scintillation spectra in the (a) UV and (b) NIR range. In the UV range, both the samples showed two emission bands at 300 and 400 nm. Similar emission bands were also reported by earlier works (Evans and Stapelbroek, 1978; Futami et al., 2014; Itou et al., 2009; Lee and
AC C
Crawford, 1979; Surdo et al., 2005), in which the origins of these emissions are ascribed to F+ and F centers, respectively. Moreover, in the NIR range, the sharp peak due to Cr3+ ion impurity was detected at 693 nm. These assignments were confirmed by scintillation decay curves shown in Fig. 4. The decay curves measured in the nano-second (ns) range were approximated by a single exponential decay function (indicated in the figure). The obtained decay time constants of transparent ceramic and single crystal were 5.4 and 8.6 ns, respectively. These values were consistent with the reported value of the decay constant due to F+ centers (Itou et al., 2009; Surdo et al., 2005). The decay curves measured in the millisecond (ms) range were approximated by a double exponential decay function (indicated in the figure). The derived decay time constants were 0.9 and 3.7 ms for transparent ceramic and 1.8 and 9.0 ms for single crystal. The fast decay constants (0.9 and 1.8 ms) measured reasonably agree with the previously reported
ACCEPTED MANUSCRIPT
value (Penill et al., 2016) due to Cr3+, so we attribute to the same origin in our samples. We infer that the remaining decay constant (3.7 and 9.0 ms) is possibly due to F centers by the elimination method; however, the measured values were not exactly consistent with the previously reported value (Itou et al., 2009; Surdo et al., 2005). A possible reason is that the emission intensity due to F centers is considerably
RI PT
low according to the observations in the spectra.
3. 3 Dosimeter properties
Fig. 5 shows TSL glow curves of the Al2O3 transparent ceramic and single crystal measured
SC
immediately and 10 min after X-ray irradiation (100 mGy) at room temperature. Both the samples showed four separate glow peaks at 50, 190, 290 and 360 °C. These peak positions are consistent with previous reports (Bin et al., 2010; Summers, 1984), and it is a typical feature of Al2O3. Despite the
M AN U
similarities, the measured intensities were very different between the transparent ceramic and single crystal. The intensity at 50 °C in the transparent ceramic was much larger than that in single crystal by a factor of ~100. Because the intensity at 50 °C is much higher in the transparent ceramic than the single crystal and the transparent ceramic was synthesized in a highly reductive atmosphere by SPS, it is reasonable to assign the origin to anion defects. Moreover, the peak intensity at 190 °C in the transparent ceramic was about 4.5 times higher than that in the single crystal. It was reported that the origin of the
TE D
peak at 190 °C is V2- centers (Summers, 1984). The origins of the 290 and 360 °C peaks are not clear, and further studies are still needed. All the glow peak intensities of the transparent ceramic were higher than those of the single crystal while all the scintillation intensities of the transparent ceramic were lower than those of the single crystal. From these results, we confirmed the complementary behavior between dosimeter and scintillation properties of the different Al2O3 matrix.
EP
Fig. 6 represents TSL spectra of the Al2O3 transparent ceramic and single crystal in the (a) UV and (b) NIR range. Both the samples showed emission bands at 300, 400 and 693 nm, and these spectral features approximately agree with those in scintillation spectra. Therefore, the origins of emission band at 300,
AC C
400 and 693 nm were ascribed to F+ centers, F centers and Cr3+ ions, respectively in accordance with the analyses of scintillation. In terms of emission band at 693 nm, the peak shape of TSL is broader than that of scintillation, and it is explained by the combination of stokes and anti-stokes lines (Rastorguev et al., 2015). In the TSL spectrum of the transparent ceramic, the intensity of 400 nm peak was larger than that of 300 nm peak while the intensity of 400 nm peak was smaller than that of 300 nm peak for the single crystal. From the application point of view, the transparent ceramic has an advantage over single crystal because most conventional photomultiplier tubes have higher sensitivity to 400 nm photon than 300 nm. TSL dose response curves of the Al2O3 transparent ceramic and single crystal are compared in Fig. 8. Here, the TSL intensity represents integrated signal of the peak at 190 °C, and the glow curves were measured approximately 10 min. after irradiation. From our experimental results, the transparent ceramic
ACCEPTED MANUSCRIPT
showed a good linearity from 0.3 to 1000 mGy while the single crystal showed a good linearity from 30 to 1000 mGy. The linearity was confirmed by coefficient of determinations (R2) derived from a leastsquare fitting of the experimental data with a numerical function (y = ax + b). As expected, the sensitivity of Al2O3 transparent ceramic was higher than that of single crystal. In our experiments, the volume of the
RI PT
transparent ceramic was smaller than the single crystal but the ceramic showed a higher TSL intensity although X-ray absorption and total luminescence intensity simply increases with the volume. Throughout the present work, we have confirmed that Al2O3 in a transparent ceramic form show higher dosimetric
SC
sensitivity than single crystal, and synthesis by using the SPS method enhances the dosimetric properties.
4. Conclusions
M AN U
We have synthesized Al2O3 transparent ceramics by the SPS technique. Subsequently, scintillation and dosimeter properties were investigated in comparison with Al2O3 single crystal. When irradiated with Xrays, both the samples showed luminescence with three band emissions at 300, 400 and 693 nm due to F+ centers, F centers and Cr3+ ions, respectively. The TSL glow curves of both samples showed glow peaks around 50, 190, 290 and 360 °C, and the luminescence origins were consistent with those measured with scintillation. Despite the similarities in the emission spectra and glow curves, the TSL intensity of the
TE D
ceramic sample was much higher than that of single crystal. Using the glow peak intensity at 190 °C, the dynamic range of the transparent ceramic was at least over the range of 0.3-1000 mGy, and the response monotonically increases with the incident dose over the dose range tested.
EP
Acknowledgements
This work was supported by Grant-in-Aid for Scientific Research (A) (17H01375), Grant-in-Aid for
AC C
Young Scientists (B) (17K14911) and Grant-in-Aid for Research Activity Start-up (16H06983) from the Ministry of Education, Culture, Sports, Science and Technology of the Japanese government (MEXT) as well as A-STEP from Japan Science and Technology Agency (JST). The Cooperative Research Project of Research Institute of Electronics, Shizuoka University, Mazda Foundation, Konica Minolta Science and Technology Foundation, NAIST Foundation and TEPCO Memorial Foundation are also acknowledged.
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
References Akselrod, A.E., Akselrod, M.S., 2002. Correlation between OSL and the distribution of TL traps in Al2O3:C, Rad. Prot. Dosi, 100, 217-220. Akselrod, M.S., Larsen, N.A., Whitley, V., McKeever, S.W.S., 1999. Thermal quenching of F center luminesce in Al2O3:C, Rad. Prot. Dosi, 84, 39-42. Bin, Z., Zhou, L., Jia, Z., Hong, Y., 2010. The fluorescence and thermoluminescence characteristics of αAl2O3:C ceramics, Chin. Phys. B, 19, 077805. Boukhair, A., Heilmann, C., Nourreddine, A., Pape, A., Portal, G., 2001. Fast neutron and γ-ray dosimetry with imaging plates, Radiat. Meas. 34, 513-516. Bulur, E., Goksu, H. Y., 1998. OSL from BeO ceramics: new observations from an old material. Radiat. Meas. 29, 639-650. Coble, R.L., 1961. Sintering Crystalline Solids. II. Experimental Test of Diffusion Models in Powder Compacts, J. Appli. Phys, 32, 793-799. Colyott, L.E., Akselrod, M.S., McKeever, S.W.S., 1996. Phototransferred themoluminescence in αAl2O3:C, Rad. Prot. Dosi, 65, 263-266. Evans, B.D., Stapelbroek, M., 1978. Optical properties of the F+ center in crystalline Al2O3, Phys. Rev B, 18, 7089-7098. Futami, Y., Yanagida, T., Fujimoto, Y., 2014. Optical, dosimetric, and scintillation properties of pure sapphire crystals, Jpn. J. Appl. Phys, 53, 02BC12. Jiang, D., Hulbert, D.M., Anselmi-Tamburini, U., Ng, T., Land, D., Mukherjee, A.K., 2008. Optically transparent polycrystalline Al2O3 produced by spark plasma sintering, J. Am. Ceram. Soc, 91, 151–154. Itou, M., Fujiwara, A., Uchino, T., 2009. Reversible Photoinduced Interconversion of Color Centers in αAl2O3 Prepared under Vacuum, J. Phys. Chem. C, 113, 20949–20957. Itoh, T., Yanagida, T., Kokubun, M., Sato, M., Miyawaki, R., Makishima, K., Takashima, T., Tanaka, T., Nakazawa, K., Takahashi, T., Shimura, N., Ishibashi, H., 2007. A 1-dimensional γ-ray position sensor based on GSO:Ce scintillators coupled to a Si strip detector, Nucl. Instrum. Methods. 579, 239-242. Kato, T., Okada, G., Yanagida, T., 2016a. Optical, scintillation and dosimeter properties of MgO transparent ceramic and single crystal, Ceram. Int. 42, 5617-5622. Kato, T., Okada, G., Yanagida, T., 2016b. Optical, Scintillation and Dosimeter Properties of MgO Translucent Ceramic Doped with Cr3+, Opt. Mater, 54, 134-138. Kato, T., Okada, G., Yanagida, T., 2016c. Optical, Scintillation and Dosimeter Properties of MgO Transparent Ceramic Doped with Mn2+, J. Ceram. Soc. Jpn, 124, 559-563. Kato, T., Okada, G., Yanagida, T., 2016d. Dosimeter Properties of MgO Transparent Ceramic Doped with C, Rad. Meas, 92, 93-98. Kato, T., Okada, G., Yanagida, T., 2017. Dosimeter Properties of CaO Transparent Ceramic Prepared by the SPS Method Journal of Materials Science: Materials in Electronics, 28, 7018. Kim, B., Hiraga, K., Morita, K., Yoshida, H., 2009. Effects of heating rate on microstructure and transparency of spark-plasma-sintered alumina, J. Eur. Ceram. Soc, 29, 323-327.
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Lee, K.H., Crawford, J.H., 1979. Luminescence of the F center in sapphire, 19, 3217-3221. Liu, Q., Yang, Q., Zhao, G., Lu, S., 2014. Titanium effect on the thermoluminescence and optically stimulated luminescence of Ti,Mg:α-Al2O3 transparent ceramics, J. Alloy. Compd, 582, 754-758. Liu, Q., Yang, Q., Zhao, G., Lu, S., Zhang, H., 2013.The thermoluminescence and optically stimulated luminescence properties of Cr-doped alpha alumina transparent ceramics, J. Alloy. Compd, 579, 259262. McKeever, S.W.S., Akselrod, M.S., Markey, B.G., 1996. Pulsed optically stimulated luminescence dosimertry using α-Al2O3:C, Rad. Prot. Dosi, 65, 267-272. McKeever, S.W.S., Akselrod, M.S., Colyott, L.E., Larsen, N.A., Polf, J.C., Whitley, V., 1999. Characterisation of Al2O3 for Use in Thermally and Optically Stimulated Luminescence Dosimetry, Rad. Prot. Dosi, 84, 163-166. McKeever, S.W.S., 2011. Optically stimulated luminescence: A brief overview, Radiat. Meas, 46, 13361340. Miyamoto, Y., Takei, Y., Nanto, H., Kurobori, T., Konnai, A., Yanagida, T., Yoshikawa, A., Shimotsuma, Y., Sakakura, M., Miura, K., Hirao, K., Nagashima, Y., Yamamoto, T., 2011. Radiophotoluminescence from silver-doped phosphate glass, Radiat. Meas. 46, 1480-1483. Nakamura, F., Kato, T., Okada, G., Kawaguchi, N., Fukuda, K., Yanagida, T., 2017a. Scintillation and Dosimeter Properties of CaF2 Translucent Ceramic Produced by SPS, J. Eur. Ceram. Soc, 37, 17071711. Nakamura, F., Kato, T., Okada, G., Kawaguchi, N., Fukuda, K., Yanagida, T., 2017b. Scintillation and Dosimeter Properties of CaF2 Transparent Ceramic Doped with Eu2+, Ceram. Inter, 43, 604-609. Nakamura, F., Kato, T., Okada, G., Kawaguchi, N., Fukuda, K., Yanagida, T., 2017c. Scintillation, TSL and RPL properties of MgF2 transparent ceramic and single crystal, Ceram. Int. 43, 7211-7215. Okada, G., Kasap, S., Yanagida, T., 2016. Optically- and thermally-stimulated luminescences of Cedoped SiO2 glasses prepared by spark plasma sintering, Opt. Mater., 61, 15-20. Penill, E.H., Hardin, C.L., Kodera, Y., Basun, S.A., Evans, D.R., Garay, J.E., 2016. The role of scattering and absorption on the optical properties of birefringent polycrystalline ceramics: Modeling and experiments on ruby (Cr:Al2O3), J. Appl. Phys, 119, 023106. Penilla, E.H., Kodera, Y., Garay, J.E., 2013. Blue–Green Emission in Terbium-Doped Alumina (Tb:Al2O3 ) Transparent Ceramics, Adv. Funct. Mater, 23, 6036–6043. Rastorguev, A., Baronskiy, M., Zhuzhgov, A., Kostyukov, A., Krivoruchko, O., Snytnikov, V., 2015. Local structure of low-temperature γ-Al2O3 phases as determined by the luminescence of Cr3+ and Fe3+, Royal. Soc.Chem, 5, 5686-5694. Roussel, N., Lallemant, L., Ching, J., Guillemet-Fristch, S., Durand, B., Garnier, V., Bonnefont, G., Fantozzi, G., Bonneau, L., Trombert, S., Garcia-Gutierrez, D., 2013. Highly Dense, Transparent αAl2O3 Ceramics From Ultrafine Nanoparticles Via a Standard SPS Sintering, J. Am. Ceram. Soc, 96, 1039–1042. Summers, G.P., 1984. Thermoluminescence in single crystalα-Al2O3, Rad. Prot. Dosi, 8, 69-80. Surdo, A.I., Pustovarov, V.A., Kortov, V.S., Kishka, A.S., Zinin. E.I., 2005. Luminescence in aniondefective α-Al2O3 crystals over the nano-, micro- and millisecond intervals., Nucl . Inst. Metho A, 543, 234-238. Yamaoka, K., Ohno, M., Terada, Y., Hong, S., Kotoku, J., Okada, Y., Tsutsui, A., Endo, Y., Abe, K., Fukazawa, Y., Hirakuri, S., Hiruta, T., Itoh, K., Itoh, T., Kamae, T., Kawaharada, M., Kawano, N., Kawashima, K., Kishishita, T., Kitaguchi, T., Kokubun, M., Madejski, G.M., Makishima, K., Mitani, T., Miyawaki, R., Murakami, T., Murashima, M.M., Nakazawa, K., Niko, H., Nomachi, M., Oonuki, K., Sato, G., Suzuki, M., Takahashi, H., Takahashi, I., Takahashi, T., Takeda, S., Tamura, K., Tanaka, T.,
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Tashiro, M., Watanabe, S., Yanagida, T., Yonetoku, D., 2005. Development of the HXD-II wide-band all-sky monitor onboard Astro-E2, IEEE Trans. Nucl. Sci. 52, 2765-2772. Yanagida, T., Yoshikawa, A., Yokota, Y., Kamada, K., Usuki, Y., Yamamoto, S., Miyake, M., Baba, M., Sasaki, K., Ito, M., 2010. Development of Pr:LuAG Scintillator Array and Assembly for Positron Emission Mammography , IEEE Trans. Nucl. Sci. 57, 1492-1495. Yanagida, T., Fujimoto, Y., Kawaguchi, N., Yanagida, S., 2013a. Dosimeter properties of AlN, J. Ceram. Soc. Jpn, 121, 988–991. Yanagida, T., Kamada, K., Fujimoto, Y., Yagi, H., Yanagitani, T., 2013b. Comparative study of ceramic and single crystal Ce:GAGG scintillator, Opt. Mater. 35, 2480–2485. Yanagida, T., Fujimoto, Y., Ito, T., Uchiyama, K., Mori, K., 2014a. Development of X-rayinduced afterglow characterization system, Appl. Phys. Express 7, 8–11. Yanagida, T., Fujimoto, Y., Watanabe, K., Fukuda, K., Kawaguchi, N., Miyamoto, Y., Nanto, H., 2014b. Scintillation and optical stimulated luminescence of Ce-doped CaF2, Radiat. Meas. 71, 162-165. Yanagida, T., 2016. Ionizing radiation induced emission: Scintillation and storage-type luminescence, J. Lumin. 169, 544-548. Totsuka, D., Yanagida, T., Fukuda, K., Kawaguchi, N., Fujimoto, Y., Yokota, Y., Yoshikawa, A., 2011. Performance test of Si PIN photodiode line scanner for thermal neutron detection, Nucl. Instrum. Methods A. 659, 399-402. Zimmerman, J., 1971. The radiation-induced increase of the 100 C thermoluminescence sensitivity of fired quartz. J. Phys. C: Solid. State. Phys. 4, 18.
ACCEPTED MANUSCRIPT
Fig. 1 Photograph of the Al2O3 transparent ceramic (left) and single crystal (right).
RI PT
Fig. 2 Transmittance spectra of the Al2O3 transparent ceramic and single crystal.
Fig. 3 Scintillation spectra of the Al2O3 transparent ceramics and single crystal in the (a) UV and (b) NIR range.
Fig .4 Scintillation decay curves of the Al2O3 transparent ceramic and single crystal in (a) ns and (b) ms
SC
range.
enlarges the 100-400 °C region.
M AN U
Fig. 5 TSL glow curves of the Al2O3 transparent ceramic and single crystal. The inset in left figure
Fig. 6 TSL spectra of the Al2O3 transparent ceramic and single crystal in the (a) UV and (b) NIR range.
AC C
EP
TE D
Fig. 7 TSL dose response curves of the Al2O3 transparent ceramic and single crystal.
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
Fig. 1 Photograph of the Al2O3 transparent ceramic (left) and single crystal (right).
ACCEPTED MANUSCRIPT
80 60 40 Transparent ceramic Single crystal
20 0
500
1000 1500 2000 Wavelength (nm)
2500
RI PT
Transmittance (%)
100
AC C
EP
TE D
M AN U
SC
Fig. 2 Transmittance spectra of the Al2O3 transparent ceramic and single crystal.
RI PT
ACCEPTED MANUSCRIPT
SC
Fig. 3 Scintillation spectra of the Al2O3 transparent ceramics and single crystal in the (a) UV and (b)
AC C
EP
TE D
M AN U
NIR range.
SC
RI PT
ACCEPTED MANUSCRIPT
M AN U
Fig .4 Scintillation decay curves of the Al2O3 transparent ceramic and single crystal in (a) ns and (b) ms
AC C
EP
TE D
range.
ACCEPTED MANUSCRIPT
60
6 4 2 0 100
150
200
250
300
350
Temperature (℃)
40
Transparent ceramic Immediately after irradiation 10 min after irradiation
20
0 50 100 150 200 250 300 350 400 450 Temperature (℃)
Single crystal
2
Immediately after irradiation 10 min after irradiation
1
RI PT
80
8
TSL intensity (a.u.)
TSL intensity (a.u.)
TSL intensity (a.u.)
3
10
100
0 50 100 150 200 250 300 350 400 450 Temperature (℃)
Fig. 5 TSL glow curves of the Al2O3 transparent ceramic and single crystal. The inset in left figure
AC C
EP
TE D
M AN U
SC
enlarges the 100-400 °C region.
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
Fig. 6 TSL spectra of the Al2O3 transparent ceramic and single crystal in the (a) UV and (b) NIR range.
ACCEPTED MANUSCRIPT
Transparent ceramic :R2=0.9918 2
Single crystal : R =0.9849 1
10
100
10-1 0.1
1
10 100 Dose (mGy)
RI PT
TSL intensity (a.u.)
102
1000
AC C
EP
TE D
M AN U
SC
Fig. 7 TSL dose response curves of the Al2O3 transparent ceramic and single crystal.
ACCEPTED MANUSCRIPT
・We have investigated thermally-stimulated luminescence (TSL) properties of Al2O3 transparent ceramic and single crystal. ・The transparent ceramic samples were fabricated by the Spark Plasma Sintering (SPS) method.
RI PT
・TSL glow curve of both the samples showed peaks at 50, 190, 290 and 360 °C. The TSL signal was confirmed to respond linearly to irradiation dose over the dose range from
AC C
EP
TE D
M AN U
SC
0.3 to 1000 mGy.
S1350-4487(17)30403-1
DOI:
10.1016/j.radmeas.2017.09.006
Reference:
RM 5838
To appear in:
Radiation Measurements
Received Date: 10 June 2017 Revised Date:
1 September 2017
Accepted Date: 20 September 2017
Please cite this article as: Kato, T., Kawano, N., Okada, G., Kawaguchi, N., Yanagida, T., Comparative study of dosimeter properties between Al2O3 transparent ceramic and single crystal, Radiation Measurements (2017), doi: 10.1016/j.radmeas.2017.09.006. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Comparative Study of Dosimeter Properties between Al2O3 Transparent Ceramic and Single Crystal Takumi Kato, Naoki Kawano, Go Okada, Noriaki Kawaguchi and Takayuki Yanagida
RI PT
Nara Institute of Science and Technology (NAIST) 8916-5 Takayama-cho, Ikoma-shi, Nara 630-0192, Japan Phone:+81-743-72-6144 Email: [email protected] Abstract
We have synthesized the Al2O3 transparent ceramic by using spark plasma sintering (SPS) and investigated the dosimeter and scintillation properties for X-ray detections, in comparison with the
SC
single crystal. Under X-ray irradiation, emissions at 300, 400 and 693 nm were observed in both the samples. To identify the origins of these emissions, scintillation decay times were investigated. Based on the results, emissions at 300, 400 and 693 nm are attributed to F+ centers, F centers and
M AN U
Cr3+ impurity ions, respectively. The thermally-stimulated luminescence (TSL) glow curves of both the samples showed a main peak around 50 °C. In addition, glow peaks were observed at 190, 290 and 360 °C. The TSL spectra had broad emission bands in the 300, 400 and 693 nm, which approximately agreed with the scintillation spectra. The TSL response was confirmed to be linear to the irradiation dose for transparent ceramic over the dose range from 0.3 to 1000 mGy while the
mGy.
TE D
sensitivity of the single crystal was lower and the response range confirmed was from 30 to 1000
AC C
EP
Keywords: transparent ceramic, Al2O3, scintillator, dosimeter
ACCEPTED MANUSCRIPT
1. Introduction Phosphors are used as radiation dosimeters for personal and environmental monitoring and in imaging plates and neutron detection for computed radiography (Boukhair et a., 2001; Bukur and Goksu,
RI PT
1998; Miyamoto et al., 2011; Zimmerman, 1971). These materials have a function to store and accumulate absorbed energy of ionizing radiation as a form of trapped electrons and holes. The electrons and holes are stored at localized trapping centers, and they recombine to emit light after de-trapping process by additional stimulation. Dosimeters based on phosphors are mainly divided into three types by different emission mechanisms. One is thermally-stimulated luminescence (TSL), which is observed by
SC
recombination of electrons and holes de-trapped from trapping centers by heat stimulation. Another is optically-stimulated luminescence (OSL) in which the stimulation is performed by light, instead of heat in TSL. The last one is radio-photoluminescence (RPL) which is a creation of new photoluminescence (PL)
M AN U
centers via interactions with ionizing radiation. Example materials used in practice today are Ti and Mg doped LiF single crystal (Zimmerman, 1971) for TSL, BeO ceramic (Bukur and Goksu, 1998) for OSL, and Ag-doped phosphate glass (Miyamoto et al., 2011) for RPL. Required properties for personal dosimetries are, for example, that the effective atomic number (Zeff) of dosimeter material is close to that of soft human body tissue (Zeff = 7.51) and that the dosimeter response monotonically increases with the incident radiation dose. In addition to the dosimeter properties, phosphors often show scintillation, which
TE D
is defined as an immediate luminescence upon radiation exposure without any additional stimulation. Scintillators are utilized in various different fields such as medicine (eg. X-ray computed tomography, PET, flat panel detector), security (eg. luggage inspection system), environmental monitoring and basic science (Itoh et al., 2007; Yamaoka et al., 2005; Yamagida et al., 2010; Totsuka et al., 2011). Recently, it was pointed out that a complementary behavior was observed between dosimeter and scintillator
EP
properties (Yanagida et al., 2014b; Yanagida, 2016); therefore, it is important to investigate both dosimeter and scintillation properties in order to comprehensively understand luminescence mechanisms
AC C
induced by ionizing radiation.
Aluminum oxide (Al2O3) was one of the classical materials studied for its possible application as a
radiation dosimeter, owing to its superior thermal stability, chemical stability and low effective atomic number close to the human body. Today, Al2O3 doped with carbon (Al2O3:C) crystals as TSL and OSL dosimeters are now well established in personal dosimetry, having been already commercially available for almost two decades (Alselrod et al., 2002; Alselrod et al., 1999; Colyott et al., 1996; McKeever et a., 1996; McKeever et al., 1999; McKever, 2011; ). Carbon ions are included to enhance defect creation as main emissions of Al2O3 are caused by several defects. On the other hand, with advancement of ceramic fabrication techniques, transparent ceramic of Al2O3 was reported (Coble, 1961; Jiang et al., 2008; Kim et al., 2009; Liu et al., 2014; Liu et al., 2013; Penilla et al., 2013; Roussel et al., 2013). However, no reports can be found about radiation responses of Al2O3 transparent ceramic material. Compared with single
ACCEPTED MANUSCRIPT
crystals, ceramic dosimeters are considered to have many advantages for a large number of defect centers included which enhance the dosimetric properties (Kato et al., 2016a; Nakamura, 2017c). In addition, ceramic materials are mechanically strong, flexibly prepared in a geometric shape of preference and cost effective.
RI PT
In this paper, we prepared Al2O3 transparent ceramics by the spark plasm sintering (SPS) method, and we investigated the dosimeter properties in comparison with the single crystal. In addition, we also studied their optical and scintillation properties in order to discuss the experimental results comprehensively. Radiation response properties of transparent ceramic are expected to be superior to those of single crystal since, in general, a larger number of defects are generated in transparent ceramic by
SC
the SPS method than those of single crystal. By using the SPS method, we have developed phosphor materials showing enhanced dosimeter and scintillator properties (Kato et al., 2016a; Kato et al., 2016b;
Nakamura et al., 2017c; Okada et al., 2016).
2. Experiment
M AN U
Kato et al., 2016c; Kato et al., 2016d; Kato et al., 2017; Nakamura et al., 2017a; Nakamura et al., 2017b;
Al2O3 transparent ceramic samples were synthesized by the SPS method using Sinter Land LabX-100. Here, a reagent grade of Al2O3 (99.99 %) powder was loaded in a graphite die and sandwiched between
TE D
two graphite punches. The sintering was carried out in three steps. First, the temperature was elevated from 25 °C to 600 °C within 5 min. Next, the temperature was slowly increased from 600 °C to 850 °C at a rate of 10 °C/min and held for 10 min while applying a pressure of 70 MPa. Finally, the temperature was further increased from 850 °C to 1300 °C at the rate of 10 °C/min and kept at 1300 °C for 20 min while applying 70 MPa pressure. After the synthesis, the wide surfaces of the obtained sample were
EP
mechanically polished with a polishing machine (MetaServ 250, BUEHLER). For comparison purposes, we purchased a single crystal from Neotron Co. Ltd. The single crystal was synthesized by the
AC C
Czochralski method.
Optical in-line transmittance spectra were evaluated by a spectrometer (V670, JASCO) over the spectral range of 190–2700 nm with 1 nm steps. In order to assign origins of emission centers, X-ray induced scintillation properties were measured. First, scintillation spectra were measured using our labconstructed setup. A sample was irradiated by X-rays generated from an X-ray tube in which the applied tube voltage and current were 40 kV and 5.2 mA, respectively. The scintillation emission was guided to a CCD-based spectrometer (Andor DU-420-BU2 or Ocean Optics QEPro depending on the spectral range) to measure the spectrum. Details of the setup was described previously (Yanagida et al., 2013b). Second, the scintillation lifetime by X-ray irradiation was measured using an afterglow characterization system equipped with a pulse X-ray tube (Yanagida et al., 2014a). The system is commercially available from Hamamatsu as a custom-ordered instrument. The applied voltage to the pulse X-ray source was 30 kV,
ACCEPTED MANUSCRIPT
and the system offers the time resolution of ~1 ns. In order to study the properties of Al2O3 transparent ceramic as a TSL dosimeter device, we have measured a TSL glow curve using a Nanogray TL-2000 (Yanagida et al., 2013a) after X-ray irradiations with various doses from 0.1 mGy to 1000 mGy. The heating rate was fixed to 1 °C/s for all the glow
RI PT
curve measurements, and the measurement temperature range was from 50 to 490 °C. Further, TSL spectrum was measured using the CCD-based spectrometer (QE Pro, Ocean Optics) while the sample was heated by an electric heater (SCR-SHQ-A, Sakaguchi E.H Voc) at a constant temperature.
SC
3. Results and discussion 3. 1 Sample
Fig. 1 shows Al2O3 transparent ceramic and single crystal samples used in this research. The
M AN U
thicknesses of the transparent ceramic and crystal samples were 0.59 and 1.00 mm, respectively. Since we polished the ceramic sample by hands, it was difficult to control the thickness precisely. Transparency of the ceramic sample was reasonably high that the black stripe patterns on the back was clearly seen. Fig. 2 shows the in-line transmittance spectra of the Al2O3 transparent ceramic and single crystal. The single crystal showed very high transmittance (80–85%) in the visible range, and the fundamental absorption edge was beyond the measurable range by the instrument. On the other hand, transmittance of the
TE D
transparent ceramic was much lower and varied 5–40% in the visible range. No particular absorption bands due to unexpected contamination were observed in both samples.
3. 2 Scintillation properties
EP
Fig. 3 represents X-ray induced scintillation spectra in the (a) UV and (b) NIR range. In the UV range, both the samples showed two emission bands at 300 and 400 nm. Similar emission bands were also reported by earlier works (Evans and Stapelbroek, 1978; Futami et al., 2014; Itou et al., 2009; Lee and
AC C
Crawford, 1979; Surdo et al., 2005), in which the origins of these emissions are ascribed to F+ and F centers, respectively. Moreover, in the NIR range, the sharp peak due to Cr3+ ion impurity was detected at 693 nm. These assignments were confirmed by scintillation decay curves shown in Fig. 4. The decay curves measured in the nano-second (ns) range were approximated by a single exponential decay function (indicated in the figure). The obtained decay time constants of transparent ceramic and single crystal were 5.4 and 8.6 ns, respectively. These values were consistent with the reported value of the decay constant due to F+ centers (Itou et al., 2009; Surdo et al., 2005). The decay curves measured in the millisecond (ms) range were approximated by a double exponential decay function (indicated in the figure). The derived decay time constants were 0.9 and 3.7 ms for transparent ceramic and 1.8 and 9.0 ms for single crystal. The fast decay constants (0.9 and 1.8 ms) measured reasonably agree with the previously reported
ACCEPTED MANUSCRIPT
value (Penill et al., 2016) due to Cr3+, so we attribute to the same origin in our samples. We infer that the remaining decay constant (3.7 and 9.0 ms) is possibly due to F centers by the elimination method; however, the measured values were not exactly consistent with the previously reported value (Itou et al., 2009; Surdo et al., 2005). A possible reason is that the emission intensity due to F centers is considerably
RI PT
low according to the observations in the spectra.
3. 3 Dosimeter properties
Fig. 5 shows TSL glow curves of the Al2O3 transparent ceramic and single crystal measured
SC
immediately and 10 min after X-ray irradiation (100 mGy) at room temperature. Both the samples showed four separate glow peaks at 50, 190, 290 and 360 °C. These peak positions are consistent with previous reports (Bin et al., 2010; Summers, 1984), and it is a typical feature of Al2O3. Despite the
M AN U
similarities, the measured intensities were very different between the transparent ceramic and single crystal. The intensity at 50 °C in the transparent ceramic was much larger than that in single crystal by a factor of ~100. Because the intensity at 50 °C is much higher in the transparent ceramic than the single crystal and the transparent ceramic was synthesized in a highly reductive atmosphere by SPS, it is reasonable to assign the origin to anion defects. Moreover, the peak intensity at 190 °C in the transparent ceramic was about 4.5 times higher than that in the single crystal. It was reported that the origin of the
TE D
peak at 190 °C is V2- centers (Summers, 1984). The origins of the 290 and 360 °C peaks are not clear, and further studies are still needed. All the glow peak intensities of the transparent ceramic were higher than those of the single crystal while all the scintillation intensities of the transparent ceramic were lower than those of the single crystal. From these results, we confirmed the complementary behavior between dosimeter and scintillation properties of the different Al2O3 matrix.
EP
Fig. 6 represents TSL spectra of the Al2O3 transparent ceramic and single crystal in the (a) UV and (b) NIR range. Both the samples showed emission bands at 300, 400 and 693 nm, and these spectral features approximately agree with those in scintillation spectra. Therefore, the origins of emission band at 300,
AC C
400 and 693 nm were ascribed to F+ centers, F centers and Cr3+ ions, respectively in accordance with the analyses of scintillation. In terms of emission band at 693 nm, the peak shape of TSL is broader than that of scintillation, and it is explained by the combination of stokes and anti-stokes lines (Rastorguev et al., 2015). In the TSL spectrum of the transparent ceramic, the intensity of 400 nm peak was larger than that of 300 nm peak while the intensity of 400 nm peak was smaller than that of 300 nm peak for the single crystal. From the application point of view, the transparent ceramic has an advantage over single crystal because most conventional photomultiplier tubes have higher sensitivity to 400 nm photon than 300 nm. TSL dose response curves of the Al2O3 transparent ceramic and single crystal are compared in Fig. 8. Here, the TSL intensity represents integrated signal of the peak at 190 °C, and the glow curves were measured approximately 10 min. after irradiation. From our experimental results, the transparent ceramic
ACCEPTED MANUSCRIPT
showed a good linearity from 0.3 to 1000 mGy while the single crystal showed a good linearity from 30 to 1000 mGy. The linearity was confirmed by coefficient of determinations (R2) derived from a leastsquare fitting of the experimental data with a numerical function (y = ax + b). As expected, the sensitivity of Al2O3 transparent ceramic was higher than that of single crystal. In our experiments, the volume of the
RI PT
transparent ceramic was smaller than the single crystal but the ceramic showed a higher TSL intensity although X-ray absorption and total luminescence intensity simply increases with the volume. Throughout the present work, we have confirmed that Al2O3 in a transparent ceramic form show higher dosimetric
SC
sensitivity than single crystal, and synthesis by using the SPS method enhances the dosimetric properties.
4. Conclusions
M AN U
We have synthesized Al2O3 transparent ceramics by the SPS technique. Subsequently, scintillation and dosimeter properties were investigated in comparison with Al2O3 single crystal. When irradiated with Xrays, both the samples showed luminescence with three band emissions at 300, 400 and 693 nm due to F+ centers, F centers and Cr3+ ions, respectively. The TSL glow curves of both samples showed glow peaks around 50, 190, 290 and 360 °C, and the luminescence origins were consistent with those measured with scintillation. Despite the similarities in the emission spectra and glow curves, the TSL intensity of the
TE D
ceramic sample was much higher than that of single crystal. Using the glow peak intensity at 190 °C, the dynamic range of the transparent ceramic was at least over the range of 0.3-1000 mGy, and the response monotonically increases with the incident dose over the dose range tested.
EP
Acknowledgements
This work was supported by Grant-in-Aid for Scientific Research (A) (17H01375), Grant-in-Aid for
AC C
Young Scientists (B) (17K14911) and Grant-in-Aid for Research Activity Start-up (16H06983) from the Ministry of Education, Culture, Sports, Science and Technology of the Japanese government (MEXT) as well as A-STEP from Japan Science and Technology Agency (JST). The Cooperative Research Project of Research Institute of Electronics, Shizuoka University, Mazda Foundation, Konica Minolta Science and Technology Foundation, NAIST Foundation and TEPCO Memorial Foundation are also acknowledged.
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
References Akselrod, A.E., Akselrod, M.S., 2002. Correlation between OSL and the distribution of TL traps in Al2O3:C, Rad. Prot. Dosi, 100, 217-220. Akselrod, M.S., Larsen, N.A., Whitley, V., McKeever, S.W.S., 1999. Thermal quenching of F center luminesce in Al2O3:C, Rad. Prot. Dosi, 84, 39-42. Bin, Z., Zhou, L., Jia, Z., Hong, Y., 2010. The fluorescence and thermoluminescence characteristics of αAl2O3:C ceramics, Chin. Phys. B, 19, 077805. Boukhair, A., Heilmann, C., Nourreddine, A., Pape, A., Portal, G., 2001. Fast neutron and γ-ray dosimetry with imaging plates, Radiat. Meas. 34, 513-516. Bulur, E., Goksu, H. Y., 1998. OSL from BeO ceramics: new observations from an old material. Radiat. Meas. 29, 639-650. Coble, R.L., 1961. Sintering Crystalline Solids. II. Experimental Test of Diffusion Models in Powder Compacts, J. Appli. Phys, 32, 793-799. Colyott, L.E., Akselrod, M.S., McKeever, S.W.S., 1996. Phototransferred themoluminescence in αAl2O3:C, Rad. Prot. Dosi, 65, 263-266. Evans, B.D., Stapelbroek, M., 1978. Optical properties of the F+ center in crystalline Al2O3, Phys. Rev B, 18, 7089-7098. Futami, Y., Yanagida, T., Fujimoto, Y., 2014. Optical, dosimetric, and scintillation properties of pure sapphire crystals, Jpn. J. Appl. Phys, 53, 02BC12. Jiang, D., Hulbert, D.M., Anselmi-Tamburini, U., Ng, T., Land, D., Mukherjee, A.K., 2008. Optically transparent polycrystalline Al2O3 produced by spark plasma sintering, J. Am. Ceram. Soc, 91, 151–154. Itou, M., Fujiwara, A., Uchino, T., 2009. Reversible Photoinduced Interconversion of Color Centers in αAl2O3 Prepared under Vacuum, J. Phys. Chem. C, 113, 20949–20957. Itoh, T., Yanagida, T., Kokubun, M., Sato, M., Miyawaki, R., Makishima, K., Takashima, T., Tanaka, T., Nakazawa, K., Takahashi, T., Shimura, N., Ishibashi, H., 2007. A 1-dimensional γ-ray position sensor based on GSO:Ce scintillators coupled to a Si strip detector, Nucl. Instrum. Methods. 579, 239-242. Kato, T., Okada, G., Yanagida, T., 2016a. Optical, scintillation and dosimeter properties of MgO transparent ceramic and single crystal, Ceram. Int. 42, 5617-5622. Kato, T., Okada, G., Yanagida, T., 2016b. Optical, Scintillation and Dosimeter Properties of MgO Translucent Ceramic Doped with Cr3+, Opt. Mater, 54, 134-138. Kato, T., Okada, G., Yanagida, T., 2016c. Optical, Scintillation and Dosimeter Properties of MgO Transparent Ceramic Doped with Mn2+, J. Ceram. Soc. Jpn, 124, 559-563. Kato, T., Okada, G., Yanagida, T., 2016d. Dosimeter Properties of MgO Transparent Ceramic Doped with C, Rad. Meas, 92, 93-98. Kato, T., Okada, G., Yanagida, T., 2017. Dosimeter Properties of CaO Transparent Ceramic Prepared by the SPS Method Journal of Materials Science: Materials in Electronics, 28, 7018. Kim, B., Hiraga, K., Morita, K., Yoshida, H., 2009. Effects of heating rate on microstructure and transparency of spark-plasma-sintered alumina, J. Eur. Ceram. Soc, 29, 323-327.
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Lee, K.H., Crawford, J.H., 1979. Luminescence of the F center in sapphire, 19, 3217-3221. Liu, Q., Yang, Q., Zhao, G., Lu, S., 2014. Titanium effect on the thermoluminescence and optically stimulated luminescence of Ti,Mg:α-Al2O3 transparent ceramics, J. Alloy. Compd, 582, 754-758. Liu, Q., Yang, Q., Zhao, G., Lu, S., Zhang, H., 2013.The thermoluminescence and optically stimulated luminescence properties of Cr-doped alpha alumina transparent ceramics, J. Alloy. Compd, 579, 259262. McKeever, S.W.S., Akselrod, M.S., Markey, B.G., 1996. Pulsed optically stimulated luminescence dosimertry using α-Al2O3:C, Rad. Prot. Dosi, 65, 267-272. McKeever, S.W.S., Akselrod, M.S., Colyott, L.E., Larsen, N.A., Polf, J.C., Whitley, V., 1999. Characterisation of Al2O3 for Use in Thermally and Optically Stimulated Luminescence Dosimetry, Rad. Prot. Dosi, 84, 163-166. McKeever, S.W.S., 2011. Optically stimulated luminescence: A brief overview, Radiat. Meas, 46, 13361340. Miyamoto, Y., Takei, Y., Nanto, H., Kurobori, T., Konnai, A., Yanagida, T., Yoshikawa, A., Shimotsuma, Y., Sakakura, M., Miura, K., Hirao, K., Nagashima, Y., Yamamoto, T., 2011. Radiophotoluminescence from silver-doped phosphate glass, Radiat. Meas. 46, 1480-1483. Nakamura, F., Kato, T., Okada, G., Kawaguchi, N., Fukuda, K., Yanagida, T., 2017a. Scintillation and Dosimeter Properties of CaF2 Translucent Ceramic Produced by SPS, J. Eur. Ceram. Soc, 37, 17071711. Nakamura, F., Kato, T., Okada, G., Kawaguchi, N., Fukuda, K., Yanagida, T., 2017b. Scintillation and Dosimeter Properties of CaF2 Transparent Ceramic Doped with Eu2+, Ceram. Inter, 43, 604-609. Nakamura, F., Kato, T., Okada, G., Kawaguchi, N., Fukuda, K., Yanagida, T., 2017c. Scintillation, TSL and RPL properties of MgF2 transparent ceramic and single crystal, Ceram. Int. 43, 7211-7215. Okada, G., Kasap, S., Yanagida, T., 2016. Optically- and thermally-stimulated luminescences of Cedoped SiO2 glasses prepared by spark plasma sintering, Opt. Mater., 61, 15-20. Penill, E.H., Hardin, C.L., Kodera, Y., Basun, S.A., Evans, D.R., Garay, J.E., 2016. The role of scattering and absorption on the optical properties of birefringent polycrystalline ceramics: Modeling and experiments on ruby (Cr:Al2O3), J. Appl. Phys, 119, 023106. Penilla, E.H., Kodera, Y., Garay, J.E., 2013. Blue–Green Emission in Terbium-Doped Alumina (Tb:Al2O3 ) Transparent Ceramics, Adv. Funct. Mater, 23, 6036–6043. Rastorguev, A., Baronskiy, M., Zhuzhgov, A., Kostyukov, A., Krivoruchko, O., Snytnikov, V., 2015. Local structure of low-temperature γ-Al2O3 phases as determined by the luminescence of Cr3+ and Fe3+, Royal. Soc.Chem, 5, 5686-5694. Roussel, N., Lallemant, L., Ching, J., Guillemet-Fristch, S., Durand, B., Garnier, V., Bonnefont, G., Fantozzi, G., Bonneau, L., Trombert, S., Garcia-Gutierrez, D., 2013. Highly Dense, Transparent αAl2O3 Ceramics From Ultrafine Nanoparticles Via a Standard SPS Sintering, J. Am. Ceram. Soc, 96, 1039–1042. Summers, G.P., 1984. Thermoluminescence in single crystalα-Al2O3, Rad. Prot. Dosi, 8, 69-80. Surdo, A.I., Pustovarov, V.A., Kortov, V.S., Kishka, A.S., Zinin. E.I., 2005. Luminescence in aniondefective α-Al2O3 crystals over the nano-, micro- and millisecond intervals., Nucl . Inst. Metho A, 543, 234-238. Yamaoka, K., Ohno, M., Terada, Y., Hong, S., Kotoku, J., Okada, Y., Tsutsui, A., Endo, Y., Abe, K., Fukazawa, Y., Hirakuri, S., Hiruta, T., Itoh, K., Itoh, T., Kamae, T., Kawaharada, M., Kawano, N., Kawashima, K., Kishishita, T., Kitaguchi, T., Kokubun, M., Madejski, G.M., Makishima, K., Mitani, T., Miyawaki, R., Murakami, T., Murashima, M.M., Nakazawa, K., Niko, H., Nomachi, M., Oonuki, K., Sato, G., Suzuki, M., Takahashi, H., Takahashi, I., Takahashi, T., Takeda, S., Tamura, K., Tanaka, T.,
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Tashiro, M., Watanabe, S., Yanagida, T., Yonetoku, D., 2005. Development of the HXD-II wide-band all-sky monitor onboard Astro-E2, IEEE Trans. Nucl. Sci. 52, 2765-2772. Yanagida, T., Yoshikawa, A., Yokota, Y., Kamada, K., Usuki, Y., Yamamoto, S., Miyake, M., Baba, M., Sasaki, K., Ito, M., 2010. Development of Pr:LuAG Scintillator Array and Assembly for Positron Emission Mammography , IEEE Trans. Nucl. Sci. 57, 1492-1495. Yanagida, T., Fujimoto, Y., Kawaguchi, N., Yanagida, S., 2013a. Dosimeter properties of AlN, J. Ceram. Soc. Jpn, 121, 988–991. Yanagida, T., Kamada, K., Fujimoto, Y., Yagi, H., Yanagitani, T., 2013b. Comparative study of ceramic and single crystal Ce:GAGG scintillator, Opt. Mater. 35, 2480–2485. Yanagida, T., Fujimoto, Y., Ito, T., Uchiyama, K., Mori, K., 2014a. Development of X-rayinduced afterglow characterization system, Appl. Phys. Express 7, 8–11. Yanagida, T., Fujimoto, Y., Watanabe, K., Fukuda, K., Kawaguchi, N., Miyamoto, Y., Nanto, H., 2014b. Scintillation and optical stimulated luminescence of Ce-doped CaF2, Radiat. Meas. 71, 162-165. Yanagida, T., 2016. Ionizing radiation induced emission: Scintillation and storage-type luminescence, J. Lumin. 169, 544-548. Totsuka, D., Yanagida, T., Fukuda, K., Kawaguchi, N., Fujimoto, Y., Yokota, Y., Yoshikawa, A., 2011. Performance test of Si PIN photodiode line scanner for thermal neutron detection, Nucl. Instrum. Methods A. 659, 399-402. Zimmerman, J., 1971. The radiation-induced increase of the 100 C thermoluminescence sensitivity of fired quartz. J. Phys. C: Solid. State. Phys. 4, 18.
ACCEPTED MANUSCRIPT
Fig. 1 Photograph of the Al2O3 transparent ceramic (left) and single crystal (right).
RI PT
Fig. 2 Transmittance spectra of the Al2O3 transparent ceramic and single crystal.
Fig. 3 Scintillation spectra of the Al2O3 transparent ceramics and single crystal in the (a) UV and (b) NIR range.
Fig .4 Scintillation decay curves of the Al2O3 transparent ceramic and single crystal in (a) ns and (b) ms
SC
range.
enlarges the 100-400 °C region.
M AN U
Fig. 5 TSL glow curves of the Al2O3 transparent ceramic and single crystal. The inset in left figure
Fig. 6 TSL spectra of the Al2O3 transparent ceramic and single crystal in the (a) UV and (b) NIR range.
AC C
EP
TE D
Fig. 7 TSL dose response curves of the Al2O3 transparent ceramic and single crystal.
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
Fig. 1 Photograph of the Al2O3 transparent ceramic (left) and single crystal (right).
ACCEPTED MANUSCRIPT
80 60 40 Transparent ceramic Single crystal
20 0
500
1000 1500 2000 Wavelength (nm)
2500
RI PT
Transmittance (%)
100
AC C
EP
TE D
M AN U
SC
Fig. 2 Transmittance spectra of the Al2O3 transparent ceramic and single crystal.
RI PT
ACCEPTED MANUSCRIPT
SC
Fig. 3 Scintillation spectra of the Al2O3 transparent ceramics and single crystal in the (a) UV and (b)
AC C
EP
TE D
M AN U
NIR range.
SC
RI PT
ACCEPTED MANUSCRIPT
M AN U
Fig .4 Scintillation decay curves of the Al2O3 transparent ceramic and single crystal in (a) ns and (b) ms
AC C
EP
TE D
range.
ACCEPTED MANUSCRIPT
60
6 4 2 0 100
150
200
250
300
350
Temperature (℃)
40
Transparent ceramic Immediately after irradiation 10 min after irradiation
20
0 50 100 150 200 250 300 350 400 450 Temperature (℃)
Single crystal
2
Immediately after irradiation 10 min after irradiation
1
RI PT
80
8
TSL intensity (a.u.)
TSL intensity (a.u.)
TSL intensity (a.u.)
3
10
100
0 50 100 150 200 250 300 350 400 450 Temperature (℃)
Fig. 5 TSL glow curves of the Al2O3 transparent ceramic and single crystal. The inset in left figure
AC C
EP
TE D
M AN U
SC
enlarges the 100-400 °C region.
RI PT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
Fig. 6 TSL spectra of the Al2O3 transparent ceramic and single crystal in the (a) UV and (b) NIR range.
ACCEPTED MANUSCRIPT
Transparent ceramic :R2=0.9918 2
Single crystal : R =0.9849 1
10
100
10-1 0.1
1
10 100 Dose (mGy)
RI PT
TSL intensity (a.u.)
102
1000
AC C
EP
TE D
M AN U
SC
Fig. 7 TSL dose response curves of the Al2O3 transparent ceramic and single crystal.
ACCEPTED MANUSCRIPT
・We have investigated thermally-stimulated luminescence (TSL) properties of Al2O3 transparent ceramic and single crystal. ・The transparent ceramic samples were fabricated by the Spark Plasma Sintering (SPS) method.
RI PT
・TSL glow curve of both the samples showed peaks at 50, 190, 290 and 360 °C. The TSL signal was confirmed to respond linearly to irradiation dose over the dose range from
AC C
EP
TE D
M AN U
SC
0.3 to 1000 mGy.