地球環境研究，Vol.17（2015）

Dose Dependence and Palaeodose Estimation for IRSLof Feldspar and Chinese Loess with Differenet Wave Ranges Using
an Automated TL/OSL System with Four Optical Paths
SHITAOKA Yorinao ＊キーワード：four optical paths, IRSL, dose dependence, palaeodose

1. Introduction

palaeodoses for three wavelengths. For the feldspar
sample, the dose dependence of 630±20 nm was the

Thermoluminescence（TL）and optically stimulated

most suitable. They used a TL system with a single

luminescence （OSL） emitted from minerals such as

photomultiplier（PMT）and changed optical filters forquartz and feldspar have been applied to archaeologicaleach measurement. However, it is difficult to select theand geological materials to date these materials（Ken-luminescence of optimum wave range to obtain the pre-nedy and Knopff 1960; Huntley et al. 1985）. The TL andferred dose dependence using a luminescence reader

OSL are caused by the electrons from the electronwith a single PMT because too much sample and timetraps as they recombine with holes in the recombina-

are wasted for the complicated experimental work.

tion center. When a mineral crystal has recombination

We designed and constructed a new TL/OSL systemcenters of several types, luminescence of several wave-that has four light paths with four condensing lenses

lengths with different cross-sections might be emitted.

and four PMTs for choosing the suitable luminescence

Consequently, the dose dependence of a particular lumi-

wave range for dating. Two feldspar specimens, albite

nescence might differ from the other luminescence of aand orthoclase, were tested to observe the difference ofdifferent wavelength. When applying TL or OSL to dat-

dose dependences for different wave ranges. The

ing of archaeological and geological materials, linear

reader apparatus was also applied to a polymineral finedose dependence is preferred along with strong lumi-grain sample extracted from Chinese loess.

nescence sensitivity.
Hashimoto et al（1986; 1997; 2003）measured TL andinfra-red stimulated luminescence（IRSL）color image

2. Automated TL/OSL Systemand TL contour maps. Baril（2004）observed IRSL ofWe designed and constructed an original TL/OSLfeldspars using charge-coupled device（CCD）cameras.

system （NRL-99-OSTL） in 1999 with two assemblies

In these cases, the samples were irradiated as much asfor heat control: one controlled from room temperatureseveral kGys before taking an image, which is far

to 500°C and another kept at -150°
C by flowing liquid

greater than the accumulated dose by geologic minerals

nitrogen（Fig. 1）. The TL/OSL system measures theused for luminescence dating.

TL and OSL up to 32 aliquots automatically. For OSL

The TL dating using quartz and feldspar extracted

measurements, an excitation assemblage with 32-470

from two tephra were performed with five different

nm light emitting diodes（LEDs; Nichia Chemical Indus-optical filters（Nagatomo et al. 1999）. For the quartztries Co., Ltd., Japan）is installed. It is interchangeablesample, they used three band-pass filters with respec-with another assemblage with 32-890 nm LEDs（Hama-tive wavelength passes of 415 nm, 500 nm, and 595 nm

matsu photonics Co., Ltd., Japan）.Luminescence from a（± 20 nm, respectively）and estimated almost identicalsample is led to a PMT（R1140P; Hamamatsu Photonics
＊Department of Environment Systems, Rissho University41

Dose Dependence and Palaeodose Estimation for IRSL of Feldspar and Chinese Loess with Differenet Wave Ranges Using
an Automated TL/OSL System with Four Optical Paths（Shitaoka）

Figure 1

Schematic diagram of NRL-₉₉-OSTL TL/OSL reader.

(a)
(b)

Figure 2

The luminescence detection assembly.
⒜ is NRL-₉₉-OSTL and ⒝ is NUE-₀₅-OSLTL.

Co., Ltd., Japan） housed in a cooling unit （-20°C）

tonics Co., Ltd., Japan）instead of two condensing lenses

through two condensing lenses and an optical filter set.

and a PMT of the NRL-99-OSTL system. Arrange-In this work, NRL-99-OSTL system was improved toments of these luminescence detection systems aredetect four-difference wave range luminescence simul-shown in Fig. 2. The wave ranges selected by the fourtaneously and to perform the single-aliquot regenera-lens and optical filter assemblages are usually 300-390

tive-dose（SAR）protocol measurements（Murray andnm, 390-590 nm, 590-650 nm, and 370-650 nm（Fig. 3）.A

Wintle 2000）. The new NUE-05-OSLTL system isdetachable 9 0 Sr- 9 0 Y beta source provided by Risøequipped with five condensing lenses and four opticalNational Laboratory, Denmark is also installed for mea-filter units and four PMTs（H7360-01; Hamamatsu Pho-surements by SAR protocol（Fig. 1）.

42

地球環境研究，Vol.17（2015）

100300 - 390nm

390 - 590nm

SV057080
SUV
60

HA15Transmittance (%)

4020

U330

0100
BG38

590 - 650nm

370 - 650nm

80
OG570
60
HA50
40

BG38

200400

600

800

1000

400

600

800

1000

Wavelength (nm)Figure ₃

The four transmission wave ranges selected by the optical ﬁlters inNUE-₀₅-OSLTL reader.

Comparing with the similar equipment developed by（NUE-05-OSLTL）. IRSL measurements were made at aDaybreak Nuclear and Medical System, Inc.（Bortolotsample temperature of 60 °C for 100 s following a pre-2000）, NUE-05-OSLTL provides four condensing lenses

heat treatment（160 °C for 60 s）（Shitaoka and Naga-

instead of a solid quartz light guide array for leading

tomo 2001）. The stimulation intensity of the infrared

luminescent light to PMTs.

LED was 86.9 mW cm-2 for IRSL measurement. The
integrated IRSL signals from 40 to 80 s for each decay

₃.

curve of four wave ranges（300-390 nm, 390-590 nm,Measurements

590-650 nm and 370-650 nm）were used for observing

₃.1 Dose Dependence of Feldspars

the dose dependence of IRSL intensity.

Two feldspars, Brazilian albite and Arizonan orthoclase, were stimulated with the 890 nm LEDs to

₃.2 Palaeodose and IRSL Age Estimation of Chi-observe the dose dependences of IRSL for the fournese Loesswave ranges. The specimens were gently crushed

Chinese loess（ca. 14 ka; Nagatomo et al. 2009）col-using a vise to obtain grains smaller than 250 µm; thenlected from the Nihewan Basin in China was crushed inthey were treated using 20% hydrochloric acid（HCl）

water, and polymineral fine grains（ca. 4-10 µm）（Zim-for 90 min to make the surface of the grains smooth.

merman 1971）were separated from coarse grains; thenFinally, the grain size was adjusted from 75 to 150 µm

treated with 10% hydrogen peroxide（H2O2）for ca. 16

using standard mesh cloth. Before irradiation, the sam-hours. Finally, polymineral fine grains were treatedples were annealed at 350 °C for 60 min in an electricwith 20% HCl for 120 min.

furnace. These samples were exposed to 1, 5, 10, 25, 50,

MAAD protocol with NUE- 0 5 -OSLTL was also

100, 500, 1000, 2000, and 3000 Gy with a Co gamma-

adapted to IRSL measurements of the polymineral fine

ray at a dose rate of ca. 0.2 Gy min .

grains to estimate the palaeodose（PD）of the Chinese

The treated feldspar specimens were measured using

loess. The measurements were made at a sample tem-

multiple aliquot additive dose（MAAD）technique（Ait-perature of 60 °C for 100 s following a preheat treat-ken 1998）with the four-wave ranges TL/OSL systemment（160 °C for 60 s）（Shitaoka and Nagatomo 2001）.

60-143Dose Dependence and Palaeodose Estimation for IRSL of Feldspar and Chinese Loess with Differenet Wave Ranges Using
an Automated TL/OSL System with Four Optical Paths（Shitaoka）

Five aliquots were used for each natural- and additive₄.2 Palaeodose Estimation of Chinese Loessdose measurements. Nonlinear dose dependence in theIRSL of polymineral fine grains extracted from thelow-dose region was corrected using samples bleached

Chinese loess was detected simultaneously through theunder sun for 8 hr（Shitaoka and Nagatomo 2001）.

four optical paths（300-390 nm, 390-590 nm, 590-650 nm

The dose rate（annual dose）of the Chinese loess was
Kand 370-650 nm）by MAAD protocol using the NUE-

measured using a gamma-ray spectrometer with a05-OSLTL. The dose responses of IRSL were linear up

highly pure Ge detector.

to the additive dose of 200 Gy. Therefore, the equiva-

evaluated from the concentrations of U, Th, and40

lent dose（ED）was evaluated from linear regression ofthe growth curve. The growth curves and the supralin-

₄. Results and discussion

earity correction（SPR）curves are presented in Fig. 5.

₄.1 Dose Dependence of Feldspars

The linear regressions of the SPR were made using theThe IRSL from albite and orthoclase are shown as adata for the given doses over 50 Gy. The PD, the sum

function of the irradiated dose from 1 to 3000 Gy in Fig.

of ED and SPR, are presented in Table 1 for the four

4. Dose dependence curves were fitted to an exponen-wave ranges. The annual dose of the Chinese loess wastial curve. IRSL from albite of four wave ranges shows

5.01±0.37 mGy a-1. Consequently, IRSL ages for eachsimilar dose dependence over 100 Gy. In the low-dosewave range were, respectively, 13±2 ka, 10±2 ka, 9±2region, the dose dependences of 300-390 nm IRSL andka, and 15±4 ka（Table 1）.

370-650 nm IRSL are almost linear, but those of 590-650

In the low-dose region of supralinearity correction

nm IRSL and 370-650 nm IRSL are exponential. Thecurves, 300-390 nm and 590-650 nm IRSL show a supra-IRSL signals of 590-650 nm from orthoclase are several

linear response, 390-590 nm and 370-650 nm IRSL aretimes more intense than those of the other wave

sublinear. It is noteworthy that the supralinearity cor-ranges, but its saturation starts at a lower dose than

rection of 370-650 nm IRSL is remarkable comparedthose of the other wave ranges. In the low dose region

with those for the other wave range IRSL because of（< 100 Gy）, the dose dependence curves of 300-390 nm

the conspicuous sublinearity. Consequently, the esti-and 370-650 nm show near linearity compared to albite.

mated palaeodoses for both 390-590 nm and 590-650 nm

Results suggest that the dose dependence of feldspar

IRSL are markedly smaller than those for 300-390 nm

IRSL of a wavelength might differ from that of theand 370-650 nm（Table 1）. The PD and IRSL age show

other wavelength, especially in the low-dose region.

good agreement with data of the reference（Nagatomo,Orthoclase

Albite1.2

1.0

IRSL Intensity (arb. units)

IRSL Intensity (arb. units)

1.0

0.8

0.6

0.3

0.20.40.8

0.6

0.7
0.6
0.5

0.4

0.4
0.3
0.2

0.1

0.2

0.2

0.1
0.0

0.0
020

40

60

80

0100

204060

80

100

0.0

0.0
0500

1000

1500

Dose (Gy)

2000

2500

3000

0500

1000

1500

2000

2500

3000

Dose (Gy)Figure ₄
Dose dependences of IRSL from two feldspars, Albite and Orthoclase.
Circle is 300-390 nm, square is 390-590 nm, triangle is 590 - 650 nm and inverse triangle is 370 - 650nm. The samples were exposed to 1, 5, 10, 25, 50, 100, 500, 1000, 2000, 3000 Gy with a 60Co gamma-ray
at a dose rate of ca. 0.2 Gy min-1.
44地球環境研究，Vol.17（2015）(a-1)

250(a-2)

250
20020015010050

9 ± 6 Gy

-55 ± 7 Gy

150

1005000-50050

100150200050

100200

Dose (Gy)

(b-1)

1.2

150(b-2)

1.2
1.0

0.8

0.8

0.60.40.2

0.6-11 ± 6 Gy

-63 ± 5 Gy

1.00.40.2

0.00.0-50

050

100

150

200050200(c-2)

706060504020

2 ± 6 Gy

-42 ± 6 Gy

400-503020100050

100

150200050

100370–650 nm Dose (Gy)

150200

Dose (Gy)

(d-1)

(d-2)

200

150-29 ± 18 Gy-103 ± 10 Gy

50150100500

IRSL Intensity (arb. units)

IRSL Intensity (arb. units)

150

Dose (Gy)

(c-1)

80100

IRSL Intensity (arb. units)

IRSL Intensity (arb. units)590–650 nm Dose (Gy)100

IRSL Intensity (arb. units)

IRSL Intensity (arb. units)

390–590 nm Dose (Gy)200

IRSL Intensity (arb. units)

IRSL Intensity (arb. units)

300–390 nm

0-1000100200

Dose (Gy)050100150200

Dose (Gy)Figure ₅
Growth curves of IRSL for four wave ranges.
（a-1）,（b-1）,（c-1）,（d-1）are for the equivalent dose estimation and（a-2）,（b-2）,（c-2）,（d-2）arefor the non-linearity correction in the low dose region. In multiple aliquot additive dose protocol,
palaeodose was obtained by the equivalent dose plus the non-linearity correction.
2009） except the low values by IRSL measurements

attributable to anomalous fading of feldspars in theusing polymineral fine grains with 390-590 nm and 590-

samples. The low-dose value estimated for 590-650 nm

650 nm wave ranges. Although the short-term fadingmight also be attributed to the fading of orange-red

tests have not been performed for these samples, theIRSL related to the influence of the yellow emission

low dose value for 390-590 nm wave range might becenter（Stokes 2003）.
45

Dose Dependence and Palaeodose Estimation for IRSL of Feldspar and Chinese Loess with Differenet Wave Ranges Using
an Automated TL/OSL System with Four Optical Paths（Shitaoka）

Table 1The estimated palaeodoses with four-wave ranges IRSL measurement,
annual dose and IRSL ages of polymineral ﬁne grains extracted fromChinese loess.

Detection
wavelength(nm)Palaeodose!Gy"

350–39063 ± 10390–59052 ± 7

Annual dose-1!mGy a "IRSL age (ka)
13 ± 210 ± 25.01 ± 0.37
590–65044 ± 89±2370–650

74 ± 2115 ± 4

The authors hope that 300-390 nm IRSL of polymineral fine grains will be checked carefully by other laboratories as an effective tool for use in OSL dating.

Hashimoto, T., Sugai, N., Sakaue, H., Yasuda, K. and Shirai,
N.（1997）Thermoluminescence（TL）spectra from quartz
grains using on-line TL-spectrometric system. Geochemical Journal, 31, 189-201.
Hashimoto, T., Usuda, H., Mitamura, N. and Yawata, T.

Acknowledgments:
The authors wish to thank Drs. T. Nagatomo, S.
Nishimura, N. Obata, H. Tissoux and M. Oishi for theirhelpful advice and discussions. The present study waspartly supported by a grant-in-aid for Fundamental（2003）Imaging and measurement of red-infrared stimulated luminescence （R-IRSL） from feldspar samples.
Ancient TL, 21, 1-6.
Huntley, D.J, Goodfrey-Smith, D.I and Thewalt, M.L.W.
（1985）Optical dating of sediments. Nature, 313, 105-107.
Kennedy, G.C. and Knopff, L.（1960）Dating by thermoluminescence. Archaeology, 13, 147-148.

Research from the Ministry of Education, Culture,Murray, A.S. and Wintle, A.G.（2000）Luminescence datingSports, Science and Technology, Japan（No. 15200059）.

of quartz using an improved single-aliquot regenerative-

The Research Fellowship of the Japan Society for thedose protocol. Radiation Measurements, 32, 57-73.

Promotion of Science（JSPS）for Young Scientists supported one author（Shitaoka, Y.）during 2006-2008.
References
Aitken, M.J.（1998）An introduction to optical dating. Oxford
University Press, 267pp.
Baril, M.R.（2004）CCD imaging of the infra-red stimulated
luminescence of feldspars. Radiation Measurements, 38,81-86.
Bortolot, V.J. （2000） A new modular high capacity OSL
reader system. Radiation Measurements, 32, 751-757.
Hashimoto, T., Hayashi, Y., Yokosaka, K., Koyanagi, A. andKimura, K.（1986）Red and blue colouration of thermoluminescence from natural quartz sands. Nuclear Tracks
Radiation Measurements, 11, 229-235.

46

Nagatomo, T., Kajiwara, H., Fujimura, S., Kamada, T., andYokoyama, Y.（1999）Luminescence dating of tephra frompaleolithic sites in Japan（from 10 ka to 500 ka）.Radiation
protection Dosimetry, 84, 489-494.
Nagatomo, T., Shitaoka, Y., Namioka, H., Sagawa, M. andWei, Q.（2009）OSL dating of the strata at Paleolithic sites
in the Nihewan basin, China. Acta Anthropologica Sinica,
28, 276-284.
Shitaoka, Y., Nagatomo, T.（2001）Studies on OSL of Quartz
and Feldspar for Dating of Sediments. Radioisotope, 50,381-389（in Japanese with English abstract）.
Stokes, S. and Fattahi, M.（2003）Red emission luminescencefrom quartzand feldspar for dating applications: an overview. Radiation Measurements, 37, 383-395.
Zimmerman, D.W.（1971）Thermoluminescent dating using
fine grains from pottery. Archaeometry, 13, 29-52.

地球環境研究，Vol.17（2015）

波長４分割同時測定による長石および中国レスの線量依存性と蓄積線量評価
下岡順直＊

立正大学地球環境科学部環境システム学科

＊

要

旨：
熱ルミネッセンス（TL）および光ルミネッセンス（OSL）年代測定では、通常一本の光電子増倍管（PMT）と一本のライトガイドを用いて蓄積線量を評価する。しかし、年代測定に供する試料は様々であり、それらから年代測定に適した線量依存性を得られるように波長領域を選択することは難しい。今回、新しいルミネッセンス測定装置 NUE05-OSLTL を作成した。この装置には、４本のライトガイドと４本の PMT を装着している。４本のライトガイドは、
300～390 nm、390～590 nm、590～650 nm そして370～650 nm に波長を選択した。そして、1～3000 Gy のγ線を照射したアルバイトと正長石の赤外励起 OSL（IRSL）における線量依存性を観察した。アルバイトおよび正長石の370～650 nm の IRSL は100 Gy 以下において、直線的な線量依存性が観察された。その一方で、590～650 nm の IRSL は他の波長領域に比べて低い線量において飽和する線量依存性が観察された。
以上の測定結果を基に、約14 ka とされる中国レスから抽出した4～10 µm の多鉱物微粒子を用いて、線量依存性と蓄積線量を評価した。その結果、50 Gy よりも低線量の300～390 nm および590～650 nm の波長領域において、IRSLがスープラリニアリティーな線量依存性を観察した。その一方で、390～590 nm および370～650 nm の IRSL では、サブリニアリティーな線量依存性を観察した。各波長領域から見積もった蓄積線量は、63±10 Gy、52±7 Gy、44±8 Gy および74±21 Gy となった。この中国レスの年間線量5.01±0.37 mGy ／年で年代に換算すると、13±2 ka、10±2 ka、9±2 ka および15±4 ka となった。このことから、この中国レスにおいては、300～390 nm の波長領域を選択する必要があることが分かった。

キーワード： 波長四分割、IRSL、線量依存性、蓄積線量

47