Nagoya University
NagoyaUniversity

Some Radiocarbon and Other Applications
at the NSF-Arizona AMS
Laboratory
A. J.T. Ju]1,
J.W. Beck, D. L. Biddulph,G. S.Burr and G W. L. Hodgins.
ws17 ArizonaAms Laboratory,Departments ofGeosciencesand Physics,
T7zeUhivensity
Tletcson,
AZ 85721, asA,ofArizona,selected applications of AMS
at the Universityof
Arizona,We introduce
sorne improvements
inAMS system and chemical processingfeatures
i4C
i29I
as well as some interestingstudies indating
ofcorals, speleothems and bones, studies;iOBenewrecordsoffrom marine sediments and extraterrestrial materials, and 26Al

In this paper,wemeasurements

highlight someon extraterrestrialmaterials.

Today, an external precisionof about ±O.35% in i4C content, or ±30 yearsinuncalibrated
radiocarbon
age ispossible
on a single
O.5-milligram-sized
sampletarget in 20 minutesofmeasurement
time, Samples as small as 1OO microgramsor lesshave been successfu11y
dated
to about ±80 yearsBP and even smaller samples (-1O-20
have
been
measuredfbr
specialpg)
experiments.
With longercounting times or when multiple targets are measured,wecanO.2%, or better than ±20 years in radiocarbon
age
et al., 2001;Donahue et aL, 1990).
(McNichol
26Al, ieBe, 36cl, 4ica
i29I,
In the case of longer-lived
radionuclides
such
as
and
which
were very difficult
to measure using counting techniques, AMS has mademeasurements
ofsmall amountof these radionuclides. This increased
sensitivity allows us to reduce
samplesize so as to preserve invaluablespecimens
such
as archaeologicalsamples,
specially
reducethe single

target error

to about

designedexperiments
insuch as biomedicalor nuclear sciences.
The NSF Arizona AMS Laboratory was one of the firstlaboratories
fbr
purpose-built
radiocarben
AMS. For the past 25 years,the capabilities of AMS measurementsof theArizonaAMS laboratory
has been expanded
to successfu11y
includeiOBe, 26Al, and i29I, withcontinuous
effbrts of a few tens ofactive
researchers
and research
associates
at the laboratory,
applications
have been expandedfrom archeology
to geology, oceanography,
andatmosphericsciences,
Julland Burr (2006)
and Jullet al. (2006)
describethe history,current
status, and futuredirectionof the AMS researchofArizona
AMS Laboratory.
Equipment
At the Arizona laboratory,we have 2 operational
accelerator
massspectrometers
Alargewasathoroughoverhaulofourmachine,a(AMS).
project
General Ionex Tandetron, including installation
ofnew
HVEE accelerator
tubes. Our secondmachine,a 3MV NEC
PelletronAMS has had a high levelof operationaltime over the last
2i29I
26Al
i4c
iOBe.
We
haveinstitued
inandmeasurements,
inaddition
toandyears.
programsService. Since 2001, the Arizona AMS facility
has providedbetween 4500 and 6000samplemeasurements
surpassing
theper year,
previous 5-yearaverage by more than 25%. In
2005 we produced 5,563 radiocarbon
measurements
and a similar numberin2006.
jFleltts
0ur
laboratory
isinvolved
in
thestudy
awide
varietyofofradiocarbon
qt'study:
and radionuclide
studies, someexamplesof which
are studies of corals, speleothems,
lake
iOBesediments,
in marine sediments, datingof fbrestfires,
datingof historicalartifacts andtextiles,terrestrial
cosmogenic
nuclides (e,g,Liftonet al,, 2001) produced in situ in rockispartof a largeinternationalsurfaces (whichCRONUS program),extraterrestrial studies ofiOBe
26Al)
i29I
radionuclides
andinlunar
samplesandmeteorites,in sea and(i4C,i4C
groundwaters, in ground water using dissolvedinorganicand organic carbon, and manyothers.
ofthis wide-ranging
We will discusssome examples
program.
"original"-40NII-Electronic Library ServiceNagoya University
NagoyaUniversity

Sanrptepretreatmentandprocessing.
We have an ongoingprogram to improve andrefine sample pretreatment
and processingtechniques, A few of the specialized techniques
foremployedin the laboratory
includesoxhlet extraction fbrtextiles,stepped combustion
sediments,
fbrcarbonates, and dissolved
organic
carbon (DOC)extraction
partialdissolution
fbrgroundwaterand ninhydnn extraction ofcarboxyl carbon fromamino acids.
LimitsqfRadiocarbon Dating: In collaboratien with Quadeet al.,we have developeda
newlow-leveli4C Extraction and Graphitization
Systems at the Universityof Arizona's
Desert Laboratory. We have also identified
ion-sourcequestionswhich have contributed tovariable
radiocarbon
blanksin the past.The recent successfu1 constructionof These Systems
has reduced
laboratory-induced
contamination
during the combustion
andgraphitizationi4C
thedatingofsample
nearlyanorderofmagnitude
andextended
phasespreparation
horizonfrom about 40,OOO to about 60,OOO yearsbefbrepresent.This advance can only be
exploited
ifitiscoupled with improvementsinthe chemical decontaminationof samples prior
to combustion.
Our objectives are three-fbld:(1)to develop sarnple handlingmethods andi4C
thedatingof bone,charcoal, and carbonates using the newquantify
practicallimitsof
i4C
extraction
and graphitization
systems,(2)to apply these new methods to datingmaterials
from Old World archaeologicalsites, and (3)to participate
in establishing a firm calibration
i4c
between
40ka.
ofagesand 60give an ideaof the breadthof the studies
Universityof ArizonaAMS Laboratory.
We

hope that this review

willundertaken

attheReferences.
corrections
fbr
D.J.Donahue, T.W. Linick,A.J.T.Jull,1990,Isotope-ratio
and backgroundaccelerator
mass spectrometry
radiocarbon measurements.
Radiocarbon32, 135-142.
A.J.T. Jull and G.S. Burr, 2006. Acceleratormass
spectrometry:Is the futurebigger orsmaller?
EarthPlanetSci.Lett.243, 305-335.
T. Lange, A, Leonard, and A,J.T.Jull,2006. Sample pretreatment protocols at the NSFArizona.RadiocarbonConference,Oxfbrd,England,April3-7,2006.
2001. A new extraction technique and prodnctionrate
N,A. Lifton,A. J. T. Jull,J. Quade,i4C
estimatefbrin situ cosmogenic
in quartz.Geochim. Cosmochim. Acta 65: 1953-1969.
L.R. McHargue

D.J. Donahue, 2005. Effectsof climate and the cosmic-ray flux on thesediments.
Earth, Planet.Sci.Lett.232, 193-207.
A.P. McNichol, A.J.T, Jull,G.S. Burr, 2001. ConvertingAMS data to radiocarbonvalues:
considerations
and conventions.
Radiocarbon43, 313-320.
iOBe

andcontent ofmarine-41-

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