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CIRCE, Dipartimento di Matematica e Fisica, Seconda Università di Napoli e INNOVA
CIRCE anno decimo
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CIRCE anno decimo.
• The Center for Isotopic Research on Cultural and Environmental heritage, operated by DMF-SUN for INNOVA Scarl, is performing since 2005 both basic research and commercial and R&D activity in the field of applied nuclear physics.
• It features a 3 MV tandem accelerator, manufactured by NEC (WI-USA), including two Cs sputtering ion sources (one for stable and another for radioactive beams), an injector featuring an electrostatic analyzer and a magnet equipped with a fast bouncing system, a pelletron two-stage accelerator, a high-energy double focusing magnet and a spherical electrostatic analyzer. A switching magnet drives the beam in one of the 5 beam lines, each equipped with different experimental systems.
• The accelerator is used both for producing intense reaction-inducing ion beams and for ultrasensitive Accelerator Mass Spectrometry of several long-lived cosmogenic isotopes.
• The talk will present the ongoing research activity in archaeometry by both high-precision radiocarbon dating and Isotope Ratio Mass Spectrometry. The interplay between basic and applied research and customer service will be discussed highlighting interferences and synergies.
Circe and Odysseus
Κίρκη
Island of Eea
Dosso Dossi (Giovanni di Niccolo Luteri)
"Circe", c. 1522-1524, canvas, Galleria
Borghese, Rome
Centro Regionale di Competenza per lo “Sviluppo e il Trasferimento dell’Innovazione Applicata ai Beni Culturali e Ambientali”
Centro per lo Sviluppo ed il Trasferimento
dell'Innovazione nel Settore dei Beni
Culturali e Ambientali – INNOVA Scarl
2002
2011
“Core business”: ● 14C dating in archaeology and earth science
• Other isotopic methodologies for environmental and cultural heritage
• Other applications of AMS and Ion Beams in basic and applied physics and industrial research
Center for Isotopic Research on Cultural and Environmental heritage
Handled by DMF-SUN
CRdC INNOVA - INNOVA Scarl: Missione • Mettere a sistema eccellenze frammentarie e scoordinate • Favorire l’incontro tra domanda (dalle imprese) e offerta (dalla ricerca) di innovazione
Soci partecipanti: • Università di Napoli Federico II • CNR • Seconda Università di Napoli • Univerità di Salerno • Università di Napoli l’Orientale • Università di Napoli Parthenope
Consiglio di Amministrazione
Comitato di Coordinamento dei Poli: • Ingegneria per i beni culturali: • Restauro dell'architettura, diagnostica dei geomateriali e prospezioni: • Servizi integrati per l'archeologia e per l’ambiente • Informatica per la rappresentazione del territorio e l'archeologia • Sistemi informativi per i beni culturali - laboratorio pluritematico di diagnostica avanzata
ADVANCED DIAGNOSTICS PLURITHEMATIC LABORATORY AIR CONDITIONING SYSTEMS FOR MUSEUM APPLICATIONS: ASSESSMENT OF EFFICIENCY AND COMPLIANCE WITH REGULATIONS ANALYSIS AND DIRECT INSRUMENTAL DETECTION OF ARCHITECTURAL AND ARCHAEOLOGICAL STRUCTURES ARCHAEOLOGICAL HERITAGE CONTEXTUALISATION DAMPNESS IN BUILDINGS: DIAGNOSIS AND PROPOSALS FOR ACTION DATING USING AN ULTRASENSITIVE ACCELERATOR MASS SPECTROMETRY SYSTEM DESIGN AND DEVELOPMENT OF GEOGRAPHIC DATABASES DIGITAL MAPPING FROM SATELLITE IMAGES ENVIRONMENTAL DATA MONITORING SERVICES FOR LAND MANAGEMENT AND NATURAL HERITAGE CONSERVATION EVALUATION AND DIAGNOSIS OF POSSIBLE MALFUNCTIONS IN ARTIFICIAL LIGHTING SYSTEMS AND NATURAL LIGHTING SYSTEMS FOR CULTURAL HERITAGE GEOARCHAEOLOGICAL SURVEY GEOPHYSICAL SURVEYS IN UNDERWATER ARCHAEOLOGY IMAGE ACQUISITION AND PROCESSING FOR CULTURAL HERITAGE INFRARED REFLECTOGRAPHY (IRR) INNOVATION DIFFUSION AND INTEGRATION INTEGRATED ESEM MICROSCOPY AND EDS WITH SUPERCONDUCTING DETECTOR INTEGRATED SERVICES FOR PREVENTIVE ARCHAEOLOGY INTEGRATED SYSTEM CONSISTING OF FOURIER TRANSFORM INFRARED (FT-IR) SPECTROMETER AND FTIR MICROSCOPE INTERFEROMETRY AND HOLOGRAPHY IN THE DIAGNOSTICS OF THE STATE OF CONSERVATION OF ARTWORKS AND ARCHAEOLOGICAL FINDS ISOTOPIC METHODS FOR ARCHAEOLOGY AND THE ENVIRONMENT LABORATORY OF TERRITORIAL CARTOGRAPHY: A TOOL FOR ENVIRONMENTAL MONITORING AND ANALYSIS LASER CLEANING/ABLATION SYSTEM MICROCLIMATE FOR HERITAGE CONSERVATION: ANALYSIS AND CONTROL MOBILE ENVIRONMENTAL MONITORING LABORATORY MOBILE LABORATORY FOR SAFETY, CONSERVATION AND PROMOTION OF THE BUILT HERITAGE MOBILE LABORATORY OF GEOPHYSICAL PROSPECTIONS FOR ARCHEOLOGY MONITORING AND CONTROL OF ARCHAEOLOGICAL SITES MORPHOMETRIC ANALYSIS MULTITHEMATIC LABORATORY OF DIAGNOSTIC SURVEYS AND TECHNIQUES FOR CULTURAL HERITAGE RESTORATION AND CONSERVATION PALAEOENVIRONMENTAL RECONSTRUCTIONS FOR ARCHAEOLOGICAL HERITAGE PALAEONTOLOGICAL AND PALAEOECOLOGICAL ANALYSIS SCANNING MAGNETIC MICROSCOPY WITH SQUID SUPERCONDUCTING SENSORS SEDIMENTOLOGY LABORATORY SERVICES FOR THE PRODUCTION OF HISTORICAL ARCHIVES SETTING UP MULTIDISCIPLINARY EDUCATIONAL PATHWAYS: CONTRIBUTIONS TO DEVELOPING CULTURAL TOURISM IN THE CAMPI FLEGREI SOIL QUALITY MONITORING LABORATORY SPECIALIST CONSULTANCY SERVICES FOR ESTABLISHING PARKS, PROTECTED AREAS AND NATURE TRAILS STRUCTURAL DIAGNOSTICS FOR THE BUILT HERITAGE STRUCTURE AND DEFECT ANALYSIS USING THERMAL IMAGING SUITE OF CONSERVATION AND PROMOTION SERVICES FOR INSTALLATIONS IN NATURAL HISTORY MUSEUMS, SHOWS, EXHIBITION SPACES; IMPLEMENTATION OF SERVICE CENTERS FOR LAND QUALITY ENHANCEMENT; PUBLISHING AND MULTIMEDIA PRODUCTS; TRAINING AND PROFESSIONAL UPDATING; EDUCATIONAL SUPPORT FOR SCHOOL PROGRAMMES AND LEISURE TIME SURVEYS FOR THE PROTECTION OF ENVIRONMENTAL AND CULTURAL HERITAGE FROM HYDROGEOLOGICAL HAZARDS TECHNOLOGY FOR RAPID ARCHAEOLOGICAL SURVEY (MONUMENTS AND STRATIGRAPHIC EXCAVATIONS) UNDERWATER SURVEYS USING THE ACU-MAG SYSTEM VIRTUAL RECONSTRUCTION OF ENVIRONMENTS VOICES OF CAMPANIA PAST AND PRESENT: PERMANENT EXHIBITION OF MULTIMEDIA LANGUAGE ARCHIVES WIDE-ANGLE X-RAY SCATTERING (WAXS) DIFFRACTOMETER WEB GIS APPLICATIONS FOR DISPLAYING, MANAGING AND HANDLING GEOGRAPHIC DATA
Alcune domande per un soggetto (pubblico o privato) che opera nel settore della ricerca applicata ai Beni Culturali
• Qual è il miglior bilanciamento tra ricerca di base, R&D e servizi? • La capacità di offrire servizi diversificati ma integrati è un valore
aggiunto? • I servizi offerti devono necessariamente limitarsi ai settore dei BC? • La commistione tra autofinanziamento e finanziamento pubblico
droga il mercato? • Qual è il modo migliore per “contabilizzare” il lavoro del personale
universitario (pubblico se il soggetto è privato) • Integrazioni reciproche dei portafogli di soggetti diversi sono utili? • Sono da preferirsi sviluppi dell’offerta orientati dalla disponibilità
strumentale o dalla domanda (attuale o prevista)? • E’ utile affrontare il calvario burocratico della certificazione ISO ..?
Forensic! • Spinoff?
a) archaeometry by high-precision radiocarbon dating;
b) environmental science by 14C-based global carbon cycle studies;
c) nuclear astrophysics by the ERNA recoil mass separator;
d) nuclear safeguards and contrast to illegal nuclear fuel use by actinides AMS;
e) forensic applications of AMS;
f) tribology by 7Be implantation.
CIRCE - FIELDS OF ACTIVITY
14C AMS
26Al AMS 129I AMS
actinides AMS
7Be implantation
Nuclear Astrophysics
service
archaeology
climate change
tree rings.
mortars
Beam time sharing
• Accelerator order (Regional EU funds (POR)) 2003
• Accelerator installation and commissioning 2005
• People: a) Structured SUN 8 b) Structured external 6
c) PhD students, fellows, .. 15 d) Visiting scientists and fellows 10
• Papers on international journals ~ 50
• Annual income a) by service activity ~160 k€/yr b) Research projects (EU,INFN,SOGIN,PRIN) ~ 450 k€/yr
A few numbers about CIRCE
The AMS system CIRCE
Pelletron 3 MV – SNICS 40 samples Applications in archaeometry and environmental science
14C/12C bkg 510-16 s< 0.3% at 10-12 13C/12C s< 0.2%
Other isotopes: 10Be, 26Al, 129I, 236U, Pu
Le piccole quantità di materiale necessario per la datazione con
AMS rendono possibili:
Analisi virtualmente non distruttive di oggetti unici. Maggiore libertà di scelta del materiale da datare,
cui consegue la possibilità di una migliore correlazione con il contesto archeologico-ambientale
La possibilità di effettuare misure su più campioni (o frazioni) dello stesso materiale o date multiple su reperti in relazione temporale tra di essi.
Una chimica di decontaminazione più rigorosa.
Microcampioni. Sorgente gassosa ? Compound specific AMS? C
30000
35000
40000
45000
50000
55000
60000
0,00 0,50 1,00 1,50 2,00 2,50 3,00 3,50 4,00
mC(mg)
RC
age (
a)
H line
Z Line
20000
25000
30000
35000
40000
45000
50000
55000
60000
0,00 0,50 1,00 1,50 2,00 2,50 3,00 3,50 4,00 4,50 5,00 5,50 6,00
mC (mg)
RC
age (
a)
Average of Apparent age for m>0.5 mg: 0.17±0.04 pMC (52000±2900a)
Average of Apparent age for m>0.5 mg: 0.13±0.08 pMC (53000±4600a)
Risultati Blank Linea Zn- reduction
Risultati Blank Linea H-reduction 1) CO2 (g) + H2(g) CO(g) + H2O(g)
2) CO(g) + H2(g) C(s) + H2O(g)
-5000
-4500
-4000
-3500
-3000
-2500
-2000
0 20 40 60 80 100 120
RC
ag
e B
P
Agnano 3Paleoastroni 2
Agnano MS
Pomici Avellino
2° Protostorica1° Protostorica
Flegrea 1
Casalb
ore
Tau
rasi
Pia
no
di
So
rren
to
(Gau
do
)
Caiv
an
o
Sala
Co
nsil
ina
Gri
cig
nan
o(L
ate
rza)
Ate
na L
ucan
a
Palm
a C
am
pan
ia
San
Pao
lo B
els
ito
San
Pao
lo B
els
ito
Po
mic
i d
i A
vell
ino
Masseri
a R
ossa
San
Pao
lo B
els
ito
La S
tarz
a
San
Pao
lo B
els
ito
San
Pao
lo B
els
ito
P.l
e T
ecch
io
Po
gg
iom
ari
no
Eneolitico Antico Eneolitico Maturo Eneolitico Finale Bronzo Antico Inizio Bronzo Medio Bronzo Recente-Finale \Ferro
l’archeologo “in casa”
THE “AVELLINO PUMICES” SOMMA-VESUVIUS ERUPTION
#
SITE
Sample
RC age (y BP)
Ref. 1
Pomigliano
Paleosoil
3510±50
Alessio 1973
2
Pomigliano
Paleosoil
3610±50
“ 3
Cava dell’Arciprete
Paleosoil
3870±50
Alessio 1974
4
Palma Campania
Paleosoil
3760±70
Delibrias 1987 5
Sarno
Charred beam
3660±45
Marzocch. 1994
6
Sarno
Charred beam
3615±45
“ 7
Terzigno
Burnt veget.
3400±160
Albore-Liv. 1998
8
Somma Vesuviana
Charcoal
3520±160
“ 9
Ottaviano
Burnt veget
3480±100
“ 10
Frattaminore
Charcoal
3400±190
“ 11
Pratola Serra
Animal bone
3450±230
“ 12
Weight. Av. 7-11
3460±65
13
S. Paolo Belsito
Female skeleton
3560±110
Albore-Liv. 1997
Conv. RC ages
AMS
Eruzione delle "Pomici di Avellino"
Donna SPBS-
NA CapraCapra-
BochumTTT3-NA
3300
3400
3500
3600
3700
1997 1999 2001 2003 2005 2007 2009anno
RCage
Three radiocarbon datings in agreement among them: Three radiocarbon datings in agreement among them:
CIRCE codeCIRCE code Sample descriptionSample description PlacePlace Date (BP)Date (BP)
DSH 145DSH 145
Goat boneGoat bone Animal pen at Croce del Papa (Nola)Animal pen at Croce del Papa (Nola)
3558 3558 ±± 2020
DSH 103DSH 103 3560 3560 ±± 2020
DSH 146DSH 146 3533 3533 ±± 2222
3550 3550 ±± 20 yr BP20 yr BP
Atmospheric data from Reimer et al (2004);OxCal v3.10 Bronk Ramsey (2005); cub r:5 sd:12 prob usp[chron]
4200CalBP 4000CalBP 3800CalBP 3600CalBP
Calibrated date
3300BP
3400BP
3500BP
3600BP
3700BP
3800BP
Radio
carb
on d
ete
rmin
ati
on
3550±20BP
68.2% probability 1935BC (68.2%) 1880BC 95.4% probability 1960BC (77.9%) 1870BC 1850BC (10.9%) 1810BC 1800BC ( 6.6%) 1770BC
US 48_Agnano Montespina
eruption
US 45_Below Avellino
AVELLINO Pumices eruption
US 30_Above Avellino
AP1
US 150_Above AP1
AP2
US 85_Above AP2
DSH 153: 3513 ±20 BP (bone)
DSH 161: 3597 ±22 BP (bone)
DSH 105: 3361 ±20 BP ; DSH 160: 3368 ±47 BP; DSH 159: 3399 ±37 BP (bones)
DSH 154: 3380 ±23 BP (bone)
S.PAOLO BELSITO: a clear stratigraphic sequence of human frequentation since the
pre-Avellino eruption until the 2nd protohistoric eruption.
S.PAOLO BELSITO: a clear stratigraphic sequence of human frequentation since the
pre-Avellino eruption until the 2nd protohistoric eruption. At m ospher i c dat a f rom Rei m er et al ( 2004) ; O xCal v3. 10 Bronk Ram sey ( 2005) ; cub r : 5 sd: 12 prob usp[ chron]
2600CalBC 2400CalBC 2200CalBC 2000CalBC 1800CalBC 1600CalBC 1400CalBC 1200CalBC
Calibrated date
Stratigraphic sequence at S.Paolo Belsito (SPBS)
DSH154_SPBS 3380±23BP
DSH105_SPBS 3361±20BP
DSH160_SPBS 3368±47BP
DSH159_SPBS 3399±37BP
DSH153_SPBS 3513±20BP
GOAT_NOLA 3550±20BP
DSH161_SPBS 3597±22BP
Radiocarbon datings from Radiocarbon datings from samples collected in samples collected in
several sites with clear several sites with clear associations of settlements associations of settlements
below and above the below and above the volcanic products of the volcanic products of the Avellino and of the first Avellino and of the first
two protohistoric two protohistoric eruptions. eruptions.
Atmospheric data from Reimer et al (2004);OxCal v3.10 Bronk Ramsey (2005); cub r:5 sd:12 prob usp[chron]
3000CalBC 2500CalBC 2000CalBC 1500CalBC
Calibrated date
Below eruption - Above the 2° protohistoric
DSH138_PC 3666±52BP
DSH161_SPBS 3597±22BP
GOAT_NOLA 3550±20BP
DSH153_SPBS 3513±20BP
DSH143_MR 3492±23BP
DSH142_SPBS 3465±19BP
DSH156_SPBS 3426±48BP
DSH76_LaStarza 3466±20BP
DSH77_LaStarza 3423±25BP
DSH78_LaStarza 3470±24BP
DSH105_SPBS 3361±20BP
DSH160_SPBS 3368±47BP
DSH159_SPBS 3399±37BP
DSH53_P.le Tecchio 3368±19BP
DSH154_SPBS 3380±23BP
Charcoal
Animal Bone
Animal Bone
Human skull
Charcoal
Animal Bone
Charcoal
Charcoal
Charcoal
Animal Bone
Animal Bone
Animal Bone
Charcoal
Animal Bone
BELOW eruption
AVELLINO eruption
ABOVE eruption
ABOVE 1°
Protohistoric
ABOVE 2° Protohistori
c
AllAll thesethese datesdates provideprovide aa furtherfurther constraintconstraint (upper(upper andand lower)lower) toto thethe AvellinoAvellino eruptioneruption..
Servizi integrati Il ritratto di Acerenza
radiografia
XRF determinazione della specie
Riflettografia infrarossa
Datazione del supporto
100
200
300
400
500
600
700
800
900
1000
1100
1300 1400 1500
RC
age
BP
calendar age AD
sequence_rings average ring # RC age error AD year last ring AD year
average ring
Model
RC age dev c
2
ISCR 1-3 -2 514 38 1410 1407 553.2 -1.0 2.207
ISCR 14-16 -15 607 31 1402-1420 1394 587.2 0.6
ISCR 30-32 -31 624 33 conf. Interv. 68% 1378 648.8 -0.7
ISCR 43-45 -44 619 33 1365 633.0 -0.4
Wiggle matching
sequence_rings average ring # RC age error AD year ring #1 AD year
average ring
Model
RC age dev2 c
2
PUNTONE_1_3 2 883 24 1159 1160 891.0 0.1 0.9
PUNTONE_16_18 17 882 24 1154-1177 1175 869.0 0.3
PUNTONE_29_31 30 874 18 conf. Interv. 68% 1188 860.6 0.5
ARCARECCIO_14_20 17 647 26 1342 1358 618.0 1.3 4.4
ARCARECCIO_50_57 53.5 577 22 1338-1348 1395 583.0 0.1
ARCARECCIO_88_94 91 551 39 conf. Interv. 68% 1432 484.0 3.0
CATENA8_10_12 11 982 21 1015 1025 986.0 0.0 0.3
CATENA8_30_32 31 953 29 1011-1020 1045 939.0 0.2
CATENA8_38_40 39 925 32 conf. Interv. 68% 1053 918.4 0.0
CATENA2_2-4 3 200 39 1653 1655 238.7 1.0 1.0
CATENA2_15-17 16 200 48 1648-1666 1668 192.4 0.0
CATENA2_28-30 29 163 35 conf. Interv. 68% 1681 161.3 0.0
MORALETTO_2-6 4 584 24 1403 1406 556.4 1.3 4.4
MORALETTO_37-41 39 431 26 1399-1408 1441 454.6 0.8
MORALETTO_72-76 74 316 38 conf. Interv. 68% 1476 373.6 2.3
100
200
300
400
500
600
700
800
900
1000
1100
1000 1100 1200 1300 1400 1500 1600
RC
age
BP
calendar age AD
intcal09
CATENA2
PUNTONE
ARCARECCIO
CATENA8
MORALETTO
Wiggle matching
• Mortars represent a class of building and art materials that are widespread at archeological sites from the Neolithic period on. They are virtually ubiquitous at archeological excavations since 7000 B.C. • Chronology of archaeological sites, mostly based on the dating of organic materials, may be affected by significant gaps between 14C dates and the real age of the site. • Comparison of mortar dates with organic samples may help in establishing the relationship between the archaeological context and the dated samples.
Factors influencing the success of mortars radiocarbon dating:
1. limestone must be completely dead-burnt before use,
otherwise dead C (primary) carbonate from bedrock will
falsify the date;
2. calcareous sand and aggregates may contain C of different
age with respect to mortar production time;
3. carbonatation must take place in a short time lag
4. running water containing dissolved CO2 can cause a
supplementary deposit on the mortar or an exchange in
carbonate ions.
VIRI Sample A
107
109
111
0 10 20 30 40 50 60 70lab #
pM
C(%
) VIRI Sample B
2600
2800
3000
0 10 20 30 40 50 60 70lab #
Rc
ag
e(a
)
VIRI Sample C
108
110
112
0 10 20 30 40 50 60 70lab #
pM
C(%
)
VIRI Sample D
2600
2800
3000
0 10 20 30 40 50 60 70lab #
Rc
ag
e(a
)
VIRI Sample E
33000
39000
45000
0 10 20 30 40 50 60 70lab #
Rc
ag
e(a
) VIRI Sample F
2300
2500
2700
0 10 20 30 40 50 60 70lab #
Rc
ag
e(a
)
VIRI Sample G
800
900
1000
1100
1200
1300
1400
0 10 20 30 40 50 60 70lab #
Rc
ag
e(a
) VIRI Sample I
7800
8300
8800
0 10 20 30 40 50 60 70lab #
Rc
ag
e(a
)
V
INTERCOMPARISON on
RADIOCARBON ANALYSIS
Certificazione di qualità
Sample A
n = 65
-2
-1
0
1
2
0.0 0.2 0.4 0.6 0.8 1.0s
D(p
MC
)
+1s
+2s
-1s
-2s
Sample B
n = 57
-150
-100
-50
0
50
100
150
0 10 20 30 40 50 60 70 80s
D(R
Ca
ge)
+1s
+2s
-1s
-2s
Sample C
n = 64
-2
-1
0
1
2
0.0 0.2 0.4 0.6 0.8 1.0s
D(p
MC)
Sample D
n = 58
-150
-100
-50
0
50
100
150
0 10 20 30 40 50 60 70s
D(R
Ca
ge)
+1s
+2s
-1s
-2s
Sample E
n = 30
-7000
-5000
-3000
-1000
1000
3000
5000
0 500 1000 1500 2000 2500 3000 3500 4000s
D(R
Cag
e)
+1
s
+2
-1s
-2s
Sample F
n = 38
-200
-100
0
100
200
0 20 40 60 80 100s
D(R
Ca
ge)
+1s
+2s
-1s
-2s
Sample G
n = 36
-200
0
200
0 50 100s
D(R
Cag
e)
+1
s
+2s
-1s
-2s
Sample I
n = 41
-200
-100
0
100
200
0 20 40 60 80 100s
D(R
Ca
ge)
+1s
+2s
-1s
-2s
z
SCORES vs
quoted
uncertainties
100
110
120
130
140
1975 1980 1985 1990 1995 2000 2005 2010 2015
pM
C (
%)
anno
TIPO_OFFSET ETICHETTE EDIZIONI FOTOCOPIE EDIZIONI_BIOPRIM MONTBLANC OFFSET2001 PALATINA AMALFI VELLUX_VLC COPY2 COPYB10
Datazione della carta (con la polizia scientifica)
1980
1990
2000
2010
1980 1985 1990 1995 2000 2005 2010 2015
raw
nominale
---- 6±2 ---- 12±2 ---- 18±2
The cesium sputter ion source is a 40-sample MCSNICS normally biased at -43 kV. Typical output from a F=1 mm sample pressed in Al cathodes for 12C- ions is 30 mA at 6 kV probe voltage and a total injection energy of 67 kV
A spherical electrostatic anal-yzer (r = 30 cm, plates gap = 5 cm) cuts the sputter energy tail of the beam, with a bending angle of ± 45°. The ESA can be rotated in view of the installation of a second ion source
The 90° double focusing L.E. magnet (r = .457 m, gap = 38 mm, ME/Z2 = 15) allows high resolution mass analysis for all stable isotopes in the periodic table. The insulated stainless steel chamber can be biased up to -15 kV for beam sequencing.
Typical injection times for 14C AMS are 350 ms for mass 12, 850 ms for m=13, and 100 ms for m=14.12C and 13C currents in the LE side Faraday cup are integrated for .1 ms and 8 ms, respectively.
The NEC 9SDH-2 Pelletron accelerator is housed in a lead-shielded steel tank filled with SF6 at ~85 psig. Two Pelletron chains are used in the charging system; about 100 mA are delivered to the terminal for operation at 3 MV.
For 14C AMS the accelerator is operated at 2.55 MV; typical ripple, as measured by a capacitive pick off, is .7 kV peak-to-peak. Stabilization is achieved by GVM feedback on the charging system PS; the long term stability, over about 24 hours needed for a batch of 40 samples, is better than 1 kV. In the stripper Ar is recirculated by two turbo-pumps; the working pressure is 10 m. The first tank opening was needed after 18 months of operation.
The double focusing 90° HE bending magnet has r=1.27 m, ME/Z2=176 and M/DM = 725, so that, e.g., 236U5+ at 3 MV can be analyzed with a beam spot size of 3.5 mm. For 14C AMS, 12C and 13C charges are measured via two off-set Faraday cups and high-precision current integrators, typically for .25 and 8 ms per cycle.
The two 45° electrostatic spherical analyzers (r= 2.54m and gap=3 cm) are operated at ± 40 kV; energy resolution is E/DE = 700. The isotopic contamination is suppressed so that virtually 0 counts are observed out of the 14C ROI