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Systematic Development of New Thermoluminescence and Optically Stimulated
Luminescence Materials
E. G. Yukihara1,*
, E. D. Milliken1, L. C. Oliveira
1, V. R. Orante-Barrón
2, L. G. Jacobsohn
3, and
M. W. Blair4
1Physics Department, Oklahoma State University, Stillwater, OK 74078, USA
2Departamento de Investigación en Polímeros y Materiales, Universidad de Sonora, Hermosillo,
Sonora 83000 México
3Center for Optical Materials Science and Engineering Technologies (COMSET),
and School of Materials Science and Engineering, Clemson University, Clemson, SC, USA
4Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM
87545, USA
* Corresponding author
Corresponding author:
Eduardo G. Yukihara
145 Physical Sciences II
Stillwater OK 74078, USA
Phone: +1-405-744-6535
E-mail: [email protected]
*ManuscriptClick here to view linked References
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Systematic Development of New Thermoluminescence and Optically Stimulated
Luminescence Materials
E. G. Yukihara1,*
, E. D. Milliken1, L. C. Oliveira
1, V. R. Orante-Barrón
2, L. G. Jacobsohn
3, and
M. W. Blair4
Abstract
This paper presents an overview of a systematic study to develop new thermoluminescence (TL)
and optically stimulated luminescence (OSL) materials using solution combustion synthesis
(SCS) for applications such as personal OSL dosimetry, 2D dose mapping, and temperature
sensing. A discussion on the material requirements for these applications is included. We present
X-ray diffraction (XRD) data on single phase materials obtained with SCS, as well as
radioluminescence (RL), TL and OSL data of lanthanide-doped materials. The results
demonstrate the possibility of producing TL and OSL materials with sensitivity similar to or
approaching those of commercial TL and OSL materials used in dosimetry (e.g., LiF:Mg,Ti and
Al2O3:C) using SCS. The results also show that the luminescence properties can be improved by
Li co-doping and annealing. The presence of an atypical TL background and anomalous fading
are discussed and deserve attention in future investigations. We hope that these preliminary
results on the use of SCS for production of TL and OSL materials are helpful to guide future
efforts towards the development of new luminescence materials for different applications.
Keywords: Thermoluminescence; Optically Stimulated Luminescence; Solution Combustion
Synthesis; Radioluminescence
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1. INTRODUCTION
Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL), also called
Photo-Stimulated Luminescence (PSL), are techniques widely used in radiation dosimetry [1-4],
luminescence dating [1, 5, 6], and computed radiography [7]. They rely on the stimulated
recombination of electrons and holes created by ionizing radiation and trapped at defects in the
crystalline lattice of the host material, leading to luminescence whose intensity is related to the
energy deposited in the detector by ionizing radiation (i.e., absorbed dose). In TL the stimulation
is provided by controlled heating of the detector [3, 4]. In OSL, stimulation is provided by
controlled illumination [1, 2].
In spite of the widespread use of TL and OSL, a demand exists for new materials with
tailored properties for specific applications, including OSL neutron dosimetry, 2D dose mapping
and temperature sensing, as discussed below.
There are a limited number of OSL materials for personal dosimetry application,
particularly for neutron dosimetry. Only two materials are commercially used in OSL dosimetry,
Al2O3:C and BeO, and this limited availability has been pointed out as a weak point of the OSL
technique [2, 8]. Moreover, these materials do not have a high cross-section for neutron
interaction, which means that they cannot be used as neutron detectors [8]. This problem has
been partially solved by preparing detectors made of a mixture of OSL material and neutron
converters [9, 10] such as 6Li or
10B, which convert neutrons into charged particles [11].
Although this solution is commercially satisfactory [12], higher neutron sensitivities could be
achieved using new OSL materials containing 6Li or
10B as part of the crystalline structure,
which would require the development of new OSL materials based on compounds such as
Li2B4O7 or MgB4O7.
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Two-dimensional dose mapping in medical dosimetry, particularly in quality assurance
and dose verification in radiotherapy, is another area of potential application of OSL materials.
Although 2D dosimetry has been performed using TL [13-16], an all-optical technique such as
OSL would be a better choice for this type of application, as evidenced by the use of the OSL in
computed radiography [7]. The main problem with using photostimulable phosphors used in
computed radiography, such as BaXBr (X = F, Cl, Br) and CsBr, for dosimetry is their high
effective atomic number [17, 18] (Zeff~50) and signal fading (> 50% in 36 h) [7, 19]. One-
dimensional dose mapping using Al2O3:C OSL detectors has been used in computed tomography
[20-22], but the luminescence lifetime of the main luminescence centers in Al2O3:C (35 ms) is
too long for 2D dosimetry readout by spot-scanning laser. OSL systems based on BeO or SrS
have been described [23, 24], but these systems present problems such as limited spatial
resolution or high effective atomic number of the detector material (e.g. Zeff = 34.6 in the case of
SrS) [2].
More recently, renewed interest has been expressed in the use of TL for temperature
sensing, in particular as passive temperature sensors in biological agent defeat tests [25], but the
lack of suitable materials is also one of the main obstacles. The concept is based on the fact that
charges trapped at different energy levels within the conduction band are affected differently by
the temperature experienced by the particles, and this can be quantified by measuring the TL
curves of particles previously irradiated: depending on the time-temperature profile, the TL
peaks would be erased differently. For this application, materials with multiple TL peaks that are
light-insensitive are required. Unfortunately, a survey of existing TL materials reveals most of
them to be light sensitive [3]. LiF:Mg,Ti is an exception, but this material is known for having a
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complex defect structure, which causes the TL properties to be dependent on the entire
temperature history, both before and after irradiation [3].
Because of the complex nature of the TL and OSL processes, which require the presence
of both recombination and trapping centers introduced by intrinsic or extrinsic defects in the host
material, development of new materials has been serendipitous. Often, the nature of the
recombination centers is known because of its characteristic emission spectrum, but that of
trapping centers responsible for the TL/OSL signal is not.
Recently, two developments increased the chances of more precisely engineering the TL
and OSL properties of materials. The first development is the demonstration that chemical routes
such as solution combustion synthesis (SCS) [26-29] may offer a more efficient way to
synthesize TL/OSL materials [30-33] and investigate the role of dopants in the TL and OSL
process. The second is the understanding that the energy levels introduced by lanthanide (Ln)
dopants and their role in the TL (and possibly OSL) process can be predicted based on a few
parameters [34-37].
Based on these developments and motivated by the lack of suitable TL and OSL
materials for different applications, we initiated a systematic study to develop new TL and OSL
materials with properties tailored for the specific applications discussed above. Our approach
uses SCS as the main synthesis method, accompanied by characterization of the crystal structure
and luminescence properties of the materials produced.
The objective of this work is to present an overview of these efforts by showing the range
of materials synthesized by SCS, typical radioluminescence (RL) spectra to show the
incorporation of luminescence centers, as well as TL and OSL of some of the samples that
exhibited high sensitivity to ionizing radiation. We also discuss the effect of Li co-doping in the
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RL and TL properties and some unexpected results related to background of the TL
measurements and fading. This work does not intend to be an exhaustive study of any single
material; see for example references [38, 39]. Instead, we focus on general observations that we
hope can be useful for other investigators working on the development of new TL and OSL
materials.
2. MATERIAL REQUIREMENTS
Table 1 summarizes the most important requirements for the specific applications
discussed above. In all cases, it is expected that the trapped charge population is stable at room
temperature.
In personal OSL dosimetry, additional requirements include a light sensitive trapped
charge population, emission in the blue-UV range of the spectrum, tissue equivalency, and
predominance of single trapping centers. Emission in the blue-UV range of the spectrum allows
for detection of light at shorter wavelengths than stimulation (blue or green), in addition to being
a better match for the spectral response of photomultiplier tubes (PMTs). In OSL dosimetry,
emission in wavelengths shorter than the stimulation wavelength makes it easier to separate
between the stimulation light and the OSL emission using optical filters [2]. Tissue equivalency
means that the host material has an effective atomic number similar to water or tissue (Zeff ~ 7.5
– 7.6), so that the detector has a response with dependence on photon energy similar to the
material of interest [17]. Predominance of a single trapping center means that that the signal is
not associated with overlapping components with different dosimetric properties (e.g., thermal
stability). Moreover, luminescence centers characterized by radiation transitions with long
lifetime are useful because of the possibility of increasing the signal-to-noise ratio using a time-
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resolved luminescence technique called pulsed OSL (POSL), in which the optical stimulation
and the luminescence detection occur asynchronously [40].
For 2D OSL dosimetry, the materials need to have an OSL resultant from luminescence
centers characterized by short luminescence lifetime, so that it is feasible to read a two-
dimensional detector in a reasonable period. In comparison with computed radiography,
applications in 2D dosimetry are less stringent in terms of sensitivity and resolution. Most of the
applications would be in quality control for radiotherapy, so the doses involved are high and
there is no patient involved. Also, dose information with spatial resolution higher than 0.1 mm is
hardly justifiable. On the other hand, requirements in terms of precision and accuracy would be
higher, since one is interested in absolute or relative dose measurements as a function of
position. To achieve that, OSL materials should have a low effective atomic number and an OSL
signal stable at room temperature to reduce the need for correction factors.
For temperature sensing applications, effective atomic number is not a constraint, but the
materials should have multiple trapping centers that are light insensitive (and if possible
characterized by simple recombination kinetics).
3. MATERIALS AND METHODS
Table 2 shows the samples obtained by SCS in this work. Because of the range of
applications discussed above, we focused on wide band-gap materials with a range of effective
atomic numbers.
The materials were prepared using oxidizers and fuels combined to obtain an elemental
stoichiometric coefficient of unity (e = 1) [41]. Typical quantities and the corresponding volume
of purified water (Type I, Milli-Q, Millipore Corporation, Billerica, MA, USA) are indicated in
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Table 2. The dopants were introduced as nitrates, and their concentrations refer to the molar
percentage relative to the metal nitrate of the host with the potential to be substituted. The
borates were prepared with a 35% excess of boric acid to account for losses during combustion
and annealing. All reagents are ACS grade obtained from Alfa-Aesar (Ward Hill, MA, USA) or
Sigma-Aldrich (Sigma-Aldrich Co, LLC, St. Louis, MO, USA).
The aqueous mixture of reagents was dried at 200 ºC for ~1.5 h on a hot plate inside a
fume hood. The temperature was then increased to 500 ºC, causing the mixture to undergo
combustion after a few minutes. The resultant powder was crushed using an agate mortar and
pestle and placed in alumina crucibles for annealing. The samples were annealed in a
temperature controlled tube furnace (Marshall model 1123, ThermCraft Inc., Winston Salem,
NC, USA) or muffle furnace (Omegalux LMF-3550, Omega Engineering, Inc., Stamford, CT,
USA) at temperatures up to 1100ºC for up to 10 h, depending on the sample. The post-
combusted and annealed powder was then crushed again using an agate mortar and pestle.
Other materials were used for comparison of the TL, OSL and RL properties. For TL we
used commercial LiF:Mg,Ti (TLD-100, Thermo Fisher Scientific, Inc., Franklin, MA, USA), for
OSL we used commercial Al2O3:C (Landauer, Inc., Glenwood, IL, USA), and for RL we used
the scintillators Lu2SiO5:Ce (LSO, Single Crystal Growth Laboratory, Los Alamos National
Laboratory, Los Alamos, NM, USA) and Gd2SiO5:C (GSO, Hitachi Chemical Co., Ltd., ) (see
[42]).
The crystalline structures of the samples were characterized by X-ray diffraction (XRD)
using a Phillips Analytical X-ray diffractometer (model PW3020) with CuK radiation and
scanning the 2 in 0.02 degree step size and 0.5 step time.
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RL spectra were obtained by exciting the samples with a 40 kV X-ray tube (MagnumTM
,
Ag transmission target, Moxtek Inc.) delivering a dose rate of approximately 150 mGy/s at the
sample position, and detecting the luminescence using a CCD fiber spectrometer (model USB-
2000, Ocean Optics Inc., Dunedin, FL, USA) via an optical fiber (1 mm core diameter,
transmission between 200 – 1100 nm). Each RL spectrum was measured using ~10 mg of
powder deposited in stainless steel cups. The spectra were not corrected for the response of the
system, which peaks at 500 nm and reaches 10% efficiency at 250 nm and 730 nm [38].
TL and OSL measurements were carried out using a Risø TL/OSL reader (model
TL/OSL-DA-15, Risø National Laboratory, Røskilde, Denmark). The TL or OSL signals were
detected using a PMT (model 9235QB, Electron Tubes, Inc.). For the TL measurements we used
Schott BG-39 filters (6 mm thickness, transmission between ~340-610 nm, Schott AG, Mainz,
Germany) in front of the PMT. The samples were heated at 5 ºC/s in high purity nitrogen gas
atmosphere. For OSL measurements, the samples were stimulated with blue LEDs (centered at
~470 nm, irradiance of ~30 mW/cm2) using Hoya U-340 filters (7.5 mm thickness, transmission
between ~290-370 nm, Hoya Corporation USA, Santa Clara, CA, USA) in front of the PMT. For
TL and OSL measurements, the samples were irradiated with ~0.5 Gy using a 90
Sr/90
Y beta
source. More details on the Risø readers can be found in Bøtter-Jensen et al. [43] and references
therein.
All RL, TL and OSL data were obtained using 10 mg of powder in stainless steel cups.
4. RESULTS AND DISCUSSION
Figure 1 shows the XRD pattern for various undoped samples produced by SCS,
demonstrating that the materials are single phase. Data on MgO have been presented elsewhere
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[38]. These results assure we obtained the desired host lattice. In the case of doped MgO:Ce,Li,
XRD reveals an additional CeO2 phase, indicating that not all dopants are incorporated into the
MgO lattice [38]. However, we have not carried out extensive XRD investigations of doped
samples yet. The XRD patterns of undoped ZrO and LaMgB5O10 presented a mixture of phases
and are not shown here.
RL measurements demonstrate the incorporation of the dopants as luminescence centers
in the materials. Figure 2 shows the RL emission spectra for three lanthanide-doped compounds
which displayed the strongest RL intensities. The main characteristic emission lines from the
trivalent lanthanides can be observed, although the intensities varied with the host material. The
emission band from Ce3+
is also observed in CaO and MgO. The RL intensity for various
lanthanide materials are compared in Table 3.
TL curves with a variety of shapes and peaks located at temperatures in the dosimetric
range were observed from these samples, some of them with intensity comparable to or higher
than commercial TL materials. Figure 3 compares the curves for materials which exhibit strong
TL with that from LiF:Mg,Ti. It is worth mentioning that for shape of the TL curve of MgO:Ln,
Li and MgB4O7:Ln, Li changes depending on the type of lanthanide used for doping. In the case
of CaO, the most intense TL (>106 counts per 0.2s) was observed for undoped samples, with
doping generally decreasing the TL intensity (results not shown here). At this point concentration
quenching curves for RL and TL were obtained for MgO:Ce,Li only [38].
OSL investigations have been focused on materials with low effective atomic number,
from which MgO showed the best results. Examples of OSL curves for MgO:Ln1%,Li3% and
various dopants are compared in Figure 4 with the OSL from commercial Al2O3:C. MgO
samples which presented the most intense OSL signals are Gd-, Nd- and Tm-doped samples, in
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which the emission from the respective trivalent lanthanides occurs in the transmission range of
the optical filters (~290-370 nm) used in the OSL measurements (see Figure 2a).
For some samples, Li co-doping substantially improved the RL or TL intensities, or both.
Figure 5 shows the effect of Li co-doping on the RL and TL of MgO doped with Dy (Figure 5a)
and Eu (Figure 5b). Note that Li co-doping not only increases the intensity of the RL and TL, but
also changes the structure of the TL curve in comparison to the undoped samples or samples
doped only with lanthanide. Improved photoluminescence properties due to the effect of Li have
been observed before for MgO [44, 45]. We speculate that Li may be acting as a charge
compensator: Li+ substituting for Mg
2+ creates a defect with net negative charge (LiMg)
that may
compensate for the incorporation of the trivalent lanthanide in the Mg site, which creates a defect
with positive effective charge (LnMg)+. Therefore, in the presence of Li, the incorporation of
trivalent lanthanide into the crystal lattice may be more effective. Moreover, the ionic radius of
Li+ (0.90Å) and Mg
2+ (0.86Å) are similar, therefore favoring the substitution. However, changes
in TL curves with Li co-doping show that Li also introduces or favors the formation of other
defects acting as trapping centers. It should be pointed out that Li co-doping did not result in a
consistent improvement in the luminescence properties of CaO.
Figure 6 shows the effect of Li co-doping on Ce-doped MgB4O7. In this material, Li co-
doping increased the TL intensity, but did not affect the RL intensity from the trivalent
lanthanides.
Annealing was also observed to improve the RL and TL of some samples, particularly in
the case of Y3Al5O12 and MgO. This is exemplified in Figure 7 for Y3Al5O12:Ce,Yb, showing
that the TL peak at 200ºC increases as the annealing temperature is increased from 900ºC to
1100ºC, whereas high temperature peaks responsible for TL above 300ºC are reduced. Other
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investigators also emphasized the importance of annealing in improving the luminescence
properties of materials produced by SCS [46, 47]. In the case of MgO:Ce,Li, annealing to
increasing temperatures improve the overall RL and TL intensities and change the relative
intensities of the TL peaks [38].
In spite of the promising results obtained using SCS for the development of new TL and
OSL materials, a few observations deserve attention. In MgAl2O4 we observed an atypical TL
background, as exemplified in Figure 8. The TL curves in Figure 8 were obtained using un-
irradiated samples, after the samples have already been annealed to 900ºC for 2h in a furnace and
heated once to 450 ºC at 5 ºC/s in the TL reader. The TL curves should exhibit a low background
(~300-500 cps) characteristic of PMT dark counts, increasing above ~400ºC due to blackbody
radiation, as illustrated Figure 8 for a MgB4O7:Ce,Li sample. It is not clear whether this atypical
emission in MgAl2O4 is due to incomplete reaction during the combustion process or annealing
that is not optimized. In any case, it is worth determining whether or not this effect is related to
the material synthesis technique.
Another important observation is the presence of anomalous fading in some samples.
This is exemplified in Figure 9 for Y3Al5O12:Ce,Yb. This sample presents a TL peak at ~200 ºC
which should be relatively stable at room temperature, but which exhibits a substantial decrease
in intensity even after a short interval following irradiation (2h). Other studies have shown that,
in YAG prepared by co-precipitation, the rate of fading increases with the concentration of Ce
and Yb, leading to the suggestion that the anomalous fading is caused by tunneling between the
Yb2+
(trapping center) and the Ce4+
(recombination center) [37]. It would also be important to
understand whether this anomalous fading is restricted to Y3Al5O12 or related to the material
synthesis technique.
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5. CONCLUSIONS
This study demonstrates the possibility of producing TL and OSL materials with
sensitivity similar to or approaching those of commercial TL and OSL materials used in
dosimetry (e.g., LiF:Mg,Ti and Al2O3:C) using SCS. Of equal importance, the SCS method
offers an efficient way for testing the influence of different dopants, allowing the introduction of
luminescence centers with emission in the wavelength of interest for different applications. The
luminescence properties can be improved by Li co-doping and annealing at an appropriate
temperature. Atypical or anomalous effects (background and fading) have been observed in some
samples and deserve more attention in future investigations. This study represents a new
paradigm in TL/OSL research whereby new materials can be discovered and designed by
systematic investigation rather than by serendipity.
More in-depth studies focused on specific materials are required to further develop useful
TL and OSL materials. There are a large number of synthesis parameters to be investigated,
including dopant concentrations, fuel-oxidizer ratios, annealing temperatures, co-dopants, and so
on. Nevertheless, we hope these preliminary results on the use of SCS for production of TL and
OSL materials are helpful to guide future efforts towards the development of new materials
needed for the applications discussed here.
ACKNOWLEDGEMENTS
The authors thank Jim Puckette (Boone Pickens School of Geology, Oklahoma State
University, Stillwater, OK) for the use of the Phillips Analytical X-ray diffractometer, and
Gregoire Denis for discussions and suggestions. This work was supported by the Oklahoma
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Center for the Advancement of Science and Technology (OCAST) through OHRS award project
number HR09-104, and by the US Defense Threat Reduction Agency (DTRA) through contract
HDTRA1-10-1-0007.
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REFERENCES
[1] L. Bøtter-Jensen, S. W. S. McKeever, A. G. Wintle, Optically Stimulated Luminescence
Dosimetry. Amsterdam: Elsevier (2003).
[2] E. G. Yukihara, S. W. S. McKeever, Optically stimulated luminescence: fundamentals
and applications: John Wiley & Sons (2011).
[3] S. W. S. McKeever, M. Moscovitch, P. D. Townsend, Thermoluminescence dosimetry
materials: properties and uses. Ashford: Nuclear Technology Publishing (1995).
[4] R. Chen, S. W. S. McKeever, Theory of thermoluminescence and related phenomena.
Singapore: World Scientific Publishing Co. (1997).
[5] M. J. Aitken, Thermoluminescence Dating. Orlando: Academic Press (1985).
[6] M. J. Aitken, An Introduction to Optical Dating. Oxford: Oxford University Press (1998).
[7] P. Leblans, D. Vandenbroucke, P. Willems, Materials 4 (2011) 1034-1086.
[8] S. W. S. McKeever, M. Moscovitch, Radiat. Prot. Dosim. 104 (2003) 263-270.
[9] J. C. R. Mittani, A. A. R. d. Silva, F. Vanhavere, M. S. Akselrod, E. G. Yukihara, Nucl.
Instrum Methods. Phys. Res. B 260 (2007) 663-671.
[10] E. G. Yukihara, J. C. R. Mittani, F. Vanhavere, M. S. Akselrod, Radiat. Meas. 43 (2008)
309-314.
[11] G. F. Knoll, Radiation Detection and Measurements: John Wiley & Sons, Inc. (2000).
[12] C. Passmore, M. Kirr, Radiat. Prot. Dosim. 144 (2011) 155-160.
[13] B. Marczewska, P. Bilski, P. Olko, M. P. R. Waligórski, Radiat. Meas. 38 (2004) 833-
837.
[14] L. Czopyk, M. Klosowski, P. Olko, J. Swakon, M. P. R. Waligorski, T. Kajdrowicz, G.
Cuttone, G. A. P. Cirrone, F. Di Rosa, Radiat. Prot. Dosim. 126 (2007) 185-189.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65
16
[15] B. Marczewska, P. Bilski, L. Czopyk, P. Olko, M. P. R. Waligórski, S. Zapotoczny,
Radiat. Prot. Dosim. 120 (2006) 129-132.
[16] P. Olko, B. Marczewska, L. Czopyk, M. A. Czermak, M. Kłosowski, M. P. R.
Waligórski, Radiat. Prot. Dosim. 118 (2006) 213-218.
[17] F. H. Attix, Introduction to radiological physics and radiation dosimetry. Weinheim:
Wiley-VCH (2004).
[18] A. J. J. Bos, Nucl. Instrum Methods. Phys. Res. B 184 (2001) 3-28.
[19] E. Ariga, S. Ito, S. Deji, T. Saze, K. Nishizawa, Med. Phys. 34 (2007) 166-174.
[20] E. G. Yukihara, C. Ruan, P. B. R. Gasparian, W. J. Clouse, C. Kalavagunta, S. Ahmad,
Phys. Med. Biol. 54 (2009) 6337-6352.
[21] C. Ruan, E. G. Yukihara, W. J. Clouse, P. B. R. Gasparian, S. Ahmad, Med. Phys. 37
(2010) 3560-3568.
[22] J. A. Bauhs, T. J. Vrieze, A. N. Primak, M. R. Bruesewitz, C. H. McCollough,
RadioGraphics 28 (2008) 245-253.
[23] A. Jahn, M. Sommer, J. Henniger, Radiat. Meas. 45 (2010) 674-676.
[24] K. Idri, L. Santoro, E. Charpiot, J. Herault, A. Costa, N. Ailleres, R. Delard, J. R. Vaille,
J. Fesquet, L. Dusseau, IEEE Trans. Nucl. Sci 51 (2004) 3638-3641.
[25] M. L. Mah, M. E. Manfred, S. S. Kim, M. Prokić, E. G. Yukihara, J. J. Talghader, IEEE
Sensors 10 (2010) 311-315.
[26] J. J. Kingsley, N. Manickam, K. C. Patil, Bull. Mater. Sci. 13 (1990) 179-189.
[27] J. J. Kingsley, K. C. Patil, Mater. Lett. 6 (1988) 427-432.
[28] L. E. Shea, J. McKittrick, O. A. Lopez, J. Am. Ceram. Soc. 79 (1996) 3257-3265.
Accep
ted fo
r pub
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on in
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al of
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scen
ce
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65
17
[29] L. A. Chick, L. R. Pederson, G. D. Maupin, J. L. Bates, L. E. Thomas, G. J. Exarhos,
Mater. Lett. 10 (1990) 6-12.
[30] V. S. M. Barros, W. M. Azevedo, H. J. Khoury, M. E. A. Andrade, P. LInhares Filho,
Radiat. Meas. 45 (2009) 435-437.
[31] V. S. M. Barros, W. M. Azevedo, H. J. Khoury, P. L. Filho, Radiat. Meas. 43 (2008) 345-
348.
[32] M. W. Blair, L. G. Jacobsohn, B. L. Bennett, S. C. Tornga, E. G. Yukihara, E. A.
McKigney, R. E. Muenchausen, Phys. Status Solidi A 206 (2009) 904-909.
[33] M. W. Blair, L. G. Jacobsohn, S. C. Tornga, O. Ugurlu, B. L. Bennett, E. G. Yukihara, R.
E. Muenchausen, J. Lumin. 130 (2010) 825-831.
[34] P. Dorenbos, J. Alloys Compd. 488 (2009) 568-573.
[35] P. Dorenbos, A. J. J. Bos, Radiat. Meas. 43 (2008) 139-145.
[36] A. J. J. Bos, P. Dorenbos, A. Bessière, B. Viana, Radiat. Meas. 43 (2008) 222-226.
[37] F. You, A. J. J. Bos, Q. Shi, S. Huang, P. Dorenbos, J. Phys.: Condens. Matter 23 (2011)
215502 (6pp).
[38] V. R. Orante-Barrón, L. C. Oliveira, J. B. Kelly, E. D. Milliken, G. Denis, L. G.
Jacobsohn, J. Puckette, E. G. Yukihara, J. Lumin. 131 (2011) 1058-1065.
[39] L. C. Oliveira, G. Denis, E. D. Milliken, J. Puckette, E. G. Yukihara, J. Lumin. (in
preparation))
[40] M. S. Akselrod, S. W. S. McKeever, Radiat. Prot. Dosim. 81 (1999) 167-176.
[41] S. R. Jain, K. C. Adiga, V. R. P. Verneker, Combust. Flame 40 (1981) 71-79.
[42] E. G. Yukihara, L. G. Jacobsohn, M. W. Blair, B. L. Bennett, S. C. Tornga, R. E.
Muenchausen, J. Lumin. 130 (2010) 2309-2316.
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18
[43] L. Bøtter-Jensen, K. J. Thomsen, M. Jain, Radiat. Meas. 45 (2010) 253-257.
[44] F. Gu, C. Li, H. Cao, W. Shao, Y. Hu, J. Chen, A. Chen, J. Alloys Compd. 453 (2008)
361-365.
[45] F. Gu, C. Z. Li, H. B. Jiang, J. Cryst. Growth 289 (2006) 400-404.
[46] L. G. Jacobsohn, S. C. Tornga, B. L. Bennett, R. E. Muenchausen, O. Ugurlu, T. K.
Tseng, J. Choi, P. H. Holloway, Radiat. Meas. 45 (2010) 611-614.
[47] E. Zych, Opt. Mater. 16 (2001) 445-452.
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19
TABLE CAPTIONS
Table 1. Examples of desirable properties for new TL/OSL materials for different applications.
Table 2. Materials produced by SCS, bandgap energy, effective atomic number, typical reagent
quantities and solution volume, and dopants investigated. The effective atomic number was
calculated as in Bos [18].
Table 3. RL intensities for various lanthanide-doped materials produced by SCS; the values are
in counts per second and correspond to the maximum intensity of the indicated emission band.
All lanthanide concentrations are 0.1%, except when indicated otherwise. The data were
obtained using powder (10 mg) and identical measurement conditions. The data are only for
qualitative comparison, since the x-ray energy deposited in different materials varies with the
mass energy absorption coefficients of each material [17] and the spectra were not corrected for
the detection response of the system [38]. The position of the lines varies depending on the
material.
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20
FIGURE CAPTIONS
Figure 1. XRD patterns of samples produced by SCS, accompanied by information on annealing
temperature and duration, powder diffraction card number, crystal system and space group: (a)
Y2O3 (1100 C for 2h, 01-083-0927, cubic, Ia-3), (b) CaO (900 C for 2h, 01-077-2376, cubic,
Fm-3m), (c) MgAl2O4 (900 C for 2h, 01-071-6329, cubic, Fd-3m), (d) MgB4O7 (900 C for 2h,
00-017-0927, orthorhombic, Pbca), (e) Al2O3 (900 C for 2h, 00-042-1468, rhombohedral, R-
3c), (f) CaAl12O19 (1200 C for 4h, 00-038-0470, hexagonal, P63/mmc), (g) LiB4O7 (860 C for
40min, 01-084-2191, tetragonal, 141cd), (h) Y3Al5O12 (900 C for 2h, 01-071-1853, cubic, Ia-
3d), (i) LiAlO2 (1200 C for 4h, 00-038-1464, tetragonal, P4212). Miller indices are presented
only for the most intense peaks. The asterisk (*) indicates an artifact introduced by the sample
holder.
Figure 2. RL spectra from (a) MgO:Li3%, (b) CaO and (c) Y2O3 undoped or doped with different
lanthanides. The spectra are offset vertically for better visualization. For comparison, the
maximum intensity from LSO:Ce and YSO:Ce scintillators in powder measured in the same
conditions are ~140 cps and 180 cps, respectively. The spectra were not corrected for the
detection response of the system [38].
Figure 3. TL curves for different lanthanide(Ln)-doped compounds synthesized by SCS: (a)
MgO; (b) Li2B4O7 and (c) MgB4O7. Panel (d) shows the TL from commercial LiF:Mg,Ti (TLD-
100) for comparison.
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21
Figure 4. OSL curves of MgO samples synthesized by SCS compared to the OSL curve of
commercial Al2O3:C measured in the same conditions. It should be pointed out the experimental
conditions used here are not optimum for Al2O3:C. Based on the emission spectrum of Al2O3:C
and transmittance spectra of optical filters, we estimate that OSL measurements of Al2O3:C using
Hoya U-340 filters (7.5 mm thickness) are 70% lower than identical measurements using filters
centered at the Al2O3:C emission band (Kopp 5113, 8 mm thickness).
Figure 5. Effect of Li co-doping on the RL and TL properties of (a) MgO:Dy and (b) MgO:Eu.
The data were obtained using 10 mg of powder in identical conditions. The samples were
annealed at 900ºC for 2h.
Figure 6. Effect of Li co-doping on the TL of MgB4O7. The samples were annealed at 900 °C for
2h.
Figure 7. Effect of annealing on the TL of yttrium aluminum garnet (YAG), Y3Al5O12, produced
by SCS.
Figure 8. Atypical background emission from un-irradiated MgAlO4 samples previously
annealed at 900ºC for 2h and then heated to 450ºC at 5ºC/s, compared with a normal background
from MgB4O7:Ce0.1%, Li1%, both prepared by SCS.
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22
Figure 9. Example of anomalous fading for yttrium aluminum garnet (YAG) Y3Al5O12 irradiated
with 0.5 Gy of beta radiation, showing the TL curve immediately after irradiation, with or
without a 2 h period in the dark before TL readout. The samples were annealed at 1100ºC for 2h.
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23
Table 1.
Application Desirable properties
All Trapped charge population stable at room temperature
Personal OSL
dosimetry Trapped charge population sensitive to light
Emission in the blue-UV region
Tissue equivalency (Zeff ~ 7.5)
Single trapping center associated with the OSL signal
Long luminescence lifetime (>100 s) in case of POSL applications
Intrinsic neutron sensitivity, i.e. having Li or B in its composition (for neutron dosimetry)
2D OSL
dosimetry Trapped charge population sensitive to light
Short luminescence lifetime (<100 s)
Emission in the blue-UV region
Tissue equivalency (Zeff ~ 7.5)
Single trapping center associated with OSL signal
Small grain sizes (~m or less)
Temperature
sensing (TL) Multiple TL peaks over a wide range of temperatures
Simple TL kinetics (first order)
Trapped charge population insensitive to light
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24
Table 2
Host Eg (eV)
Zeff Reagents Dopants investigated (co-doping indicated in parenthesis)
ZrO2 ~5 36.3 11.9 g Zr(NO3)26H2O; 3.5 g
urea, 50ml
Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb
Y2O3 5.6 36.1 7.6 g Y(NO3)36H2O, 3 g urea,
50ml
Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, (Ce,Sm), (Ce,Dy), (Ce,Tm), (Eu,Sm),
(Eu,Dy), (Eu,Tm), (Tb,Sm), (Tb,Dy), (Tb,Tm), (Tb,Eu)
MgAl2O4 5.8 11.2 7.8 g Mg(NO3)26H2O, 23.2 g
Al(NO3)39H2O
12.2 g urea, 50ml
Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb
Y3Al5O12 7.5 30.6 8.1 g Y(NO3)36H2O, 13.5 g
Al(NO3)39H2O
8.6 g urea, 50ml
Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, (Ce,Sm), (Ce,Eu), (Ce,Yb), (Tb:Sm), (Tb,Eu) , (Tb,Yb), (Ce,Eu,Yb), (Tb,Eu,Yb)
LaMgB5O10 41.5 4.3 g La(NO3)36H2O, 2.7 g
Mg(NO3)26H2O, 3.2g H3BO3;
2.1 g glycine, 100ml
Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Li
CaO 7.1 18.3 16.7 g Ca(NO3)24H2O, 7.1 g
urea, 50ml
Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Li
MgB4O7 8.5 5.2 g Mg(NO3)26H2O, 6.7g H3BO3, 2.0 g urea, 100ml
Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Tm, Yb , (Ce, Pr), (Ce, Nd), (Ce, Dy), (Ce, Tm), (Tb, Pr), (Tb, Nd), (Tb, Dy), (Tb, Tm), Li, Na, K
Al2O3 9.5 11.3 15.5 g Al(NO3)39H2O, 6.1 g
urea, 50ml
Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Li ,Zn, Zr, Si, Ag, Fe, Mn, Ni, Cu,
(Zr,Si), (Zr,P), (Zr, Tb), Li
CaAl12O19 12.4 0.74 g Ca(NO3)24H2O, 14.1 g
Al(NO3)29H2O, 6.0 g urea, 50ml
Ce, Eu, Li
Li2B4O7 7.5 7.3 7.0 g LiNO3, 12.6g H3BO3,
8.0g NH4NO3, 5.71 glycine, 50ml
Dy, Ce, Mn, Cu, Ag, (Cu, Ag), Ni, Cr
CaAl2O4 7.4 14.8 3.1 g Ca(NO3)24H2O, 10.0 g
Al(NO3)39H2O, 5.4 g urea, 50ml
Ce, Eu, Li
MgO 7.8 10.8 13.1 g Mg(NO3)26H2O, 5.1 g
urea, 50ml
Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Li, Al, (Ce,Gd), (Nd,Gd), (Ce,Ca), (Ce,
La), (Ce, Dy), (Ce, Eu), (Ce, Er), (Ce, Tm), (Ce, Yb), ( Ce, Tb), La , Ca, Na, Ba, K, Al ,
Fe, Cr, Mn, P, Si, Co, Zn, Zr, In, (In,Gd), (In, Nd), Ti , Cu, Ag, (Cu, Ag), Ni, (Ce:Gd),
(Nd:Gd), (Nd, Ho), (Nd, Tm), (Ce,Ca), (Fe, Mn), (Nd, Ho), (Nd, Dy), (Nd, Gd),
(Nd,Tm), (Nd, Ho), (Nd, Er)
LiAlO2 10.7 7.5 g Al(NO3)39H2O, 5.2 g
urea, 1.4 g LiNO3, 50ml
Ce
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25
Table 3
Ce Pr
~620nm Nd
~396nm Sm
~600nm Eu
~600nm Gd
313nm Tb
544nm Dy
~570nm Ho
548nm Er
~407nm
Tm
454nm
Al2O3 30* <1 13 13 30 10 100 25 <1 6 13
CaO 80 60 <1 210 100 90 250 390 25 <20 80
MgB4O7:Li1% <1 <1 <1 4 1 2 17 35 <1 <1 14
LaMgB5O10 <1 1 <1 25 <1 1 14 35 <1 <1 22
Y2O3 <1 50 <1 70 140 50 175 250 <20 <20 <20
Y3Al5O12 70 25 <20 60 60 30 35 <20 <1 <1 <1
MgO:Li3%
(Ln1%)
80 1 20 18 60 6 6 16 <1 <1 6
*The emission is probably due to F centers, since undoped samples also show similar emission band.
“<1” indicates undetected or weak emission.
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20 40 60
(622
)
(611
)
(440
)
(134
)(3
32)
(411
)(400
)(2
22)
(211
)
*
Inte
nsity
(ar
b. u
nits
) (a) Y2O
3
20 30 40 50 60
*
(311
)
(220
)
(200
)
(111
)
(b) CaO
20 30 40 50 60
*
(511
)(4
22)
(400
)
(311
)
(220
)
(111
)
(c) MgAl2O
4
20 30 40 50 60
(810
)(7
02)(5
13)
(232
)(5
12)
(421
)(402
)(321
)(3
02)(2
20)
(311
)(0
20)
(211
)(2
10)
(d) MgB4O
7
Inte
nsity
(ar
b. u
nits
)
20 40 60
(018
)(1
16)
(024
)
(113
)
(110
)
(104
)
*(0
12)
(e) Al2O
3
20 30 40 50 60
*
(217
)(2
01)
(206
)(205
)(2
03)
(114
)
(107
)(1
10)
(006
)
(102
)
(d) CaAl12
O19
20 30 40 50 60
(512
)
(224
)(2
04)
(004
)(3
12)
(202
)(2
11)
(112
)
(g) Li2B
4O
7
(200
)
Inte
nsity
(ar
b. u
nits
)
2 (deg.)
20 30 40 50 60
* (800
)(642
)(6
40)
(444
)
(611
)
(521
)
(422
)(4
20)
(400
)(3
21)
(211
)
(h) Y3Al
5O
12
2 (deg.)
20 30 40 50 60
(302
)(2
22)
(310
)
(113
)(2
20)
(211
)(2
01)
(200
)
(102
)(1
11)
(110
)
(101
)
(i) LiAlO2
2 (deg.)
Figure 1
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20
40
60
80
100
120
140
160
180
200
220
240
260 (a) MgO:Li3%
Yb
Tm
Er
Ho
Dy
Tb
Gd
Eu
Sm
Nd
Pr
Ce
undoped
200 400 600 8000
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300 (b) Y2O
3(b) CaO
Wavelength (nm)200 400 600 8000
50
100
150
200
250
300
350
400
450
500
550
600
650
RL
inte
nsity
(cp
s)
Figure 2
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0.2
0.4
0.6
0.8
1.0
Ce
Sm (1100oC/6h)
Nd (0.5%)
(a) MgO:Ln1%
,Li3%
100 200 300 4000.0
0.1
0.2
0.3
0.4(b) Li
2B
4O
7:Cu
0.3%,Ag
0.3%
100 200 300 4000
1
2
3
4
5
TmDy
Tb
Ce
(c) MgB4O
7:Ln
0.1%,Li
1%
TL
inte
nsity
(10
6 cou
nts
per
0.2s
)
Temperature (oC)
100 200 300 4000.0
0.2
0.4
0.6
0.8
1.0 (d) LiF:Mg,Ti (TLD-100)
Figure 3
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0.5
1.0
1.5
2.0
2.5
3.0
MgO:Sm1%
,Li3%
MgO:Tm1%
,Li3%
MgO:Nd1%
,Li3%
MgO:Gd1%
,Li3%
OS
L in
tens
ity (
106 c
oun
ts p
er
0.2
s)
Time(s)
Al2O
3:C
Figure 4
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4
6
8
10
12
14
16
Dy1%
Dy1%
,Li3%
(a) MgO:Dy1%
RL
inte
nsity
(cp
s)
Wavelength (nm)100 200 300 400
0.0
0.2
0.4
0.6
0.8
undopedDy
1%
Dy1%
,Li3%
TL
inte
nsity
(10
5 cou
nts
per
0.2s
)
Temperature (ºC)
400 500 600 700 8000
10
20
30
40
50
60
Eu1%
Eu1%
,Li3%
(b) MgO:Eu1%
RL
inte
nsity
(cp
s)
Wavelength (nm)100 200 300 400
0.0
0.5
1.0
1.5
undopedEu
1%
Eu1%
,Li3%
TL
inte
nsity
(10
5 cou
nts
per
0.2s
)
Temperature (ºC)
Figure 5
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4
6
8 Ce0.1%
Li1%
Ce0.1%
Li0.1%
Ce0.1%
undopedTL
inte
nsity
(10
5 cou
nts/
0.2s
)
Temperature (oC)
MgB4O
7
Figure 6
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2
3
4
5
1100oC/2h
1100oC/10h
900oC/2h
TL
inte
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(10
5 cou
nts/
0.2s
)
Temperature (oC)
YAG:Ce0.1%
,Yb0.1%
Figure 7
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MgB4O
7:Ce
0.1%,Li
1%
Ce
PrNd
SmEu
Gd
Tb
MgAl2O
4:Ln
0.1%
TL
inte
nsity
(10
4 coun
ts p
er 0
.2s)
Temperature (oC)
Figure 8
Accep
ted fo
r pub
licati
on in
the
Journ
al of
Lumine
scen
ce
100 200 300 4000
1
2
3
4
+ 2h
YAG:Ce0.1%
,Yb0.1%
TL
(105 c
ount
s pe
r 0.
2s)
Temperature (oC)
Figure 9
Accep
ted fo
r pub
licati
on in
the
Journ
al of
Lumine
scen
ce