Nagoya University
NagoyaUniversity

i4C

Present Status of AMS

facilityof Nagoya Universityand itsapplications

to archeology
Toshio NAKAMURA",

TakahiroWATANABE,

geologyandHirotaka ODA, Akiko IKEDA,

Masayo MINAMI,

Hiroko MIYAHARA,
MasamiTomoko OHTA, ShigeoYOSHIOKA

andNISHIDA

Centerfor ChronologicalResearch,Ndgaya UhiversiijL
Chikusa,IVdgqya464-8602 Jbpan
author:(borresponding

Phone:+8i-52-789-308ny

e-mail:nakamura@nendai,nagQya-u.ac,1'p,

A i`C AMS

systembuiltby HVEE, B.V.,the Netherlands,
was delivered
to Nagoya

Universityin 1996, finishedfinalacceptance testsin Januaryof 1999,andi`C±O.3% to ± O.4% (abit 1argerthancountingstatistics)

andthe uncertainty

1679, 1771 and1115 in eachtargets of

big machinemeasuredmostin eight years.Since wemeasurementby the results

couldofis aroundfrom i4C

330, 1430,2077, 1003, 1,979,

wastotal number

andhave repeatedfbrced to reduce

ofthree- ortoneeded

be one of the bestcompared

FIRI and VIRI competitions.

from June to October in 2006, whichwith

We had athe numberoftargets.

InternationalradiocarbonThecalculated(each30 min.) on each target,rather Iongeryearswerelevelof quality,as shown
troubleO.3%

year from 1999 to 2006, respectiyely,it,However, the qualityof eachthe world±ratios

ratios is ± O.03% to ± O.07%, as areof targetsmeasured

11,384 is achieved

fbur-times measurements
attainof about

i3C!i2C

that of the corresponding

testedforHOxll targets.The number

measuredi`Cfi2Cdeviation(lsigma)of thein 2000. The standard

measurements

started routinely

recentone,

intercomparisonhas been conducted

the Fifth InternationalRadiocarbon

fu1filled
in 2004-2005,TheNagoya AMS
firsttime and VIRI isthe second

case.

University,Scotland,a chairperson

offbur times already,Intercomparison (VIRI)wasin the forthonegroup participatedforthe(FIRI)

According to a report by Prof.Scottof the Glasgow
this program, 66 organizations(thenumberin FIRI

jn,and out of them, AMS groups were 32 (25),liquidprogram was 92) have participatedscinti]lationand gas proportionalcountergroups (GPC)werelO
groups (LSC)were 31 (49),Participations
by AMS(18),

groups have increasedrelatively this time compared
were four.Two of them (sampleA andinFIRI program.The samples distributedwerebar]eymash(sampleB andwithsampleratherD)

werehigh i4C

concentration

charredseeds

excavated

harvestedin recent
at archeologicalwiththosesample

C)year. Other twosites. To us AMS-3]NII-Electronic Library Service

Nagoya University
NagoyaUniversityi`Cgroup,2g of each barleymash and 4 grainseach charred seed sample were deliveredfOranalysis.
From each fbursample, two graphitetargets were preparedand analyzed forcarbon

i4C
isotoperatios, i.e.,
fi2Cand

i3Cli2C,

stated previously.
The results are summarized

asinTable 1.

The results by Nagoya group are consistent with the averages
by all parti¢ ipants.
However, wethe results

bithigher values

andconcentration

B. We need moreages on sample

Table 1

in i4C

maynoticeyoungerones inteststo check

Comparison of the VIRI results

i4C

valuesSampleNoAverageMedian1sigmaMinimum

by Nagoya group are aage, inparticular,
one of themeasured

i4C

by Nagoya AMS group

NagoyaAMS

Maximum
value

value

92

113.0

A(pMC)108.6109.12.78

ofvalues

thistendency,

the relevant

andthat the yalues

or median( lo)±109.6±O.3
109.7± O.3

B(BP)28252821

198.7

2460

3979

2752 ± 25
2803 ± 28C(pMC)109.8110.6

98.6

2.35

112.6

110.7±O.3
110.9±O.3

D(BP)28592835

185.2

2580

3998

2811 ± 252832±

Precise estimationof agefor not

only archeological25

but also historicalevents is

the timing of introducing rice
gettingmore and more importantin Japan, For example,
farming,along with agricultural tools forrice farming to Japan, is re-examined by i`C dates
withhigh precision,
To provide accurate
techniquesmatching
accuracy

andfor woodsamples

to the events, agcageestimationis quitepromising,Therefbre,weprecisiontests by measuring

i4C

age

for eachannualby i"Cwiggle

are conducting

ring of abig tree, ina Japanese tree,whose
age was determinedby dendrochronology,
fbrtheteststhat
particular,i`Cthe established
IntCa198 and IntCal04
data sets are really consistentwith
thei4C-concentration

records

in Japanese trees.

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