From large AMS facilities to table size instruments supplies Electronics AMS-12-Topic: Technical...
Transcript of From large AMS facilities to table size instruments supplies Electronics AMS-12-Topic: Technical...
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
From large AMS facilities to table size instrumentsMartin Suter
Ion Beam Physics, ETH Zurich, Switzerland
∼ 200 x∼ 1000x∼
20
x
∼
12 x
Voltage: 6-10 MVEnergy: 30-50 MeVLength: 40
m
Costs: 10 M€
Voltage:
0.04 MVEnergy:
0.04 MV
Length:
2.0
mCosts:
0.8
M€
Rochester MP-Tandem, 1977Mc Master University, 1977
ETH 2011
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
AMS development
at ETH Zürich
1995-200910Be, 14C,26Al,41Ca,129I,Pr,236U, Pu;
Modified
for
AMS1979-1984
10Be,14C,26Al,32Si,36Cl,41Ca,129I
EN 6MV-Acceleratorbuilt
1960-1964
Tandy: 0.55 MV Pelletron
(NEC)
2000-2010
ETH/PSI:MICADAS, 200 kV, 14C
2 x 2 m
2010-2014 ETH ZurichRadiocarbon
MS, 45
keV
3 x 4 m
Multi-isotope
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Organisation of the
Laboratory of Ion Beam
Physics
Head LIPScientist, D-PHYS
Physics-Department Institute of Particle Physics
Ion Beam PhysicsInstrumentation
Materials Researchwith Ion Beams
AMS Applications Technical Support
Scientific Board with representatives from
D-PHYS, IPP, D-ERDW, EAWAG, EMPA, PSI
Application groups
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Laboratory of Ion Beam
Physics
(LIP) Physics
Department, ETHZ
Research Scientists: 7Post. Docs:
4PhD
Students:
3Techn. Staff
13Administration
1Retired
(Scienists)
2___________________________Total
~30==========================Guests
0 -
4Students
0 -
3
Head: Dr. Hans-Arno Synal
Staff working on instrumentation
Tandy550 kV
CompactRadiocarbon40-
200 kV
Technical
staff
for
instrumentation: 10
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Sample Statistics
LIP
~7500in 2010
with
3 accelerators, 6 MV, 550 kV,
200kV
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
1979 -
1991:
AMS at ETH1991 -
2008:
Head of Laboratory of Ion Beam Physics, Professor in Department of Physics
May 2008 Early retirement
2008-
2011
Participating in some projects at ETH
AMS Vienna, Austria2 months
Sevilla, Spain6 months
Aster, Aix, France3 months
AMS Peking University China2 weeks
Martin Suter
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
My interest and my dreams
-Smaller-Cheaper-More reliable-High performance-Universal
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Computer development
(1970-2010)
Memory: 64 kBHarddisk : 5 MBClock: 20 MHzVolume:0.8 x 2 x 4 =6.4 m3
PDP-15, 1970 2010
Volume: 0.0006 m2
Memory: 64 GB, Clock:1GHz
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
AMS: Reduction
of EnergyEnergy 14C-Measurements:1977 40 MeV1984 9 MeV1998 1 MeV2002 0.4 MeV2011 0.045 MeV
Voltage (Stripping Energy)1977 8.0 MV 4+1984 2.2 MV 3+1998 0.5 MV 1+2002 0.22 MV 1+2011 0.045 MV 1+
Energy 10Be1980 40 MeV1984 5.32008 0.75
t1/2
=3.5 years
Destruction of moleculesby collisions, 1+,2+
He-Stripping
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
How
can
we
make
better
and smaller Instruments for
AMS?
=> New Instruments/ better performance/ cheaper/ smaller
TechnologiesIdeas
Physics
Finances + Infrastructure
Ideas:New conceptsNew methodsNew designsImproved Methods
Physis of AMS:Existing models
Existing data
⇒ Better models
⇒ New dataNot good enough !
Not good enough!
New technologies:Materials (SiN-foils)Components (pumps)Power suppliesElectronics
AMS-12-
Topic: Technical
Advances, Non-standard
AMS isotopes
(NOT PHYSICS)
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
What kind of physics?
Ion- Atom Collisions: Scattering, Ionisation, Electron transfer
Ion- Molecule Collisions
Ion gas & solid interactions
Ion interaction with electricand magnetic fields (ion optics)
Ion Beam Physics (keV - MeV)
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Principle
of AMS for
14C
Sample,ion
beam
14C Filter
14C Filter
14C Filter
14C Filter
14C Filter
2 10+14
Atoms/sec, 32 μA of C 100 Atoms/sec of 14C
Mass-spectro-metermass
separation
Mass- spectro-
metermass
separation
Detectorisobar
separationNegativeIon source
IsobarSeparation
Particle Accelerator
destruction of molecules
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Tandem accelerators: Size and Voltage
2 4 6 8 10Terminal Voltage in MeV
2
4
6
8
10
12
14
16
htgneLm
Power Supply(Tandtron, HV)
Pelletron, NEC
Large and Extra Large
Medium
Small and extra small
~ Pr
ice
in M
€
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Charge state
yield
and accelerator
size
q > 2 molecules
unstable
q < 3 molecules
stable
4+3+1+ 2+
Carbon
in Ar
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Destruction
of molecules in the stripping
process
1) Stripping
to q >2: complete
destruction
2) Stripping
to q < 3Destruction
in collisions: Reduction
of intensity
13CH, 12CH2 , 7Li2
A.E. Litherland, NIM B5(1984)100; Lee NIM B5 (1984)208
I=I0 e-σd
Intensity
of CH+
has to be
reduced
by
11 orders
!
1
10
100
1'000
10'000
100'000
1'000'000
0.00 0.20 0.40 0.60 0.80 1.00 1.20Stripper thickness
/ µg /cm2N
umbe
rof d
etec
ted
ions
@ m
ass
14 a
mu
JacobLee
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Construction of a compact AMS facility by ETH/PSIIn collaboration with NEC (accelerator company, USA)
Background: 14C/12C = 0.1 -
0.6 *10-14
Accuracy: 0.3-0.5 %Transmission: 40 -50 %
=> Almost equivalent in performancecompared to largerfacilities (2-6 MV)
1999: Carbon dating ispossible at 0.4 to 0.5 MV
Nucl. Instr. and Meth.
B172 (2000) 1 (IBA-19
)
6 m
4 m
Other developments at the same time: Newton Scientific , HVEE
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Further
developments
: 2000-2010
Smaller
instrumentsfor
radiocarben
Compact multi isotopeInstruments:10Be, 26Al, 41Ca, 129I, 236U, 239,240
Pu
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Is
a „universal“
AMS system
with compact
500 kV possible?
1)
Problems: small
angle scattering
2) Yield
(Stripping, Scattering)
3) Detection
identification
of isobars
Examples: 10Be-10B238,239Pu
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Prinziple of an Ionizations Chamber used in AMS
ΔEEres
Cathode
Anode(s)
(Frisch-)-GridEntrance foil
Multichannelanalyser
HV ~ 100 V
E ∼
Q = q x (E / EI )
EI = 20 – 40 eV for GasesEI = 3.6 eV for Si
Signals are factor 10 smaller1 MeV →
2 - 4 10+4 Electrons
0 20 40 60 80 1000
20
40
60
80
00
d Settings \suter \My Documents \Jan04 \DPGMü nchen \be
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Detector development
1) Energy reduction in entrance window
2) Energy resolution
3) Pulse height (and defect)
4) Isobar separation
Isobar separation at low energies : 10Be-
10BM/q Ambiguities :
240Pu3+ -
160Dy2+, 80Se1+
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Detector developmentDetector development
DesignCompactGood shielding 2005
ElectronicsLow NoiseCooled FET (2005)
Entrance windowSiN-foil 34 nm (2002)
Detector resolution:1) Entrance window2) Electronics3) Gas4) Geometry, field configuration
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Energy
straggling
in foil: 34
nm Si3
N3.1
: Results
and Model
Yang model is in good agreement with the experiments !
Energies:0.4 MeV0.8 MeV1.2 MeV1.6 MeV
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Energy
resolution
for
light ions
(m <14, E=0.1-2 MeV)
Electronic noiseis
relevant !
From
Arnold Müller
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Gas detectors at low energies ?U (E = 1.2 MeV) is stopped in 70 μg/cm2 Polypropylene!
Simulation with SRIM program
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
m/q-ambiguities
240Pu3+-160Dy2+
Pu-Spektren 1.2 und 0.8 MeV
0
200
400
600
800
1000
1200
0 50 100 150
channel
events 1280 keV (STD)
1280 keV (Sample)835 kV (Standard)835 kV (Sample)
Pu Pu
Pu-Spektren 1.2 und 0.8 MeV
0.00.00.00.00.00.10.10.10.1
0 50 100 150
channel
events
1280 keV (STD)1280 keV (Sample)835 kV (Standard)835 kV (Sample)
Pu isotopes
could
be
measured
with
200 kV tandem
!
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
-45° Projection onto diagonal axis in ΔE - ER plane
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
250 300 350 400 450
Channel
Cou
nts
(nor
mal
ized
)
C14
C13H
-45° Projection onto diagonal axis in ΔE - ER plane
1
10
100
1000
10000
250 300 350 400 450
Channel
Cou
nts C14
C13H
Separation of molecules; 13CH-14C
13CH
E = 0.96 MeV, 1+
14C13CH 14C
13CH can
be
suppressed
by
2 orders
of magnitude
with
a gas counter
!
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
without additional magnet
Sample:
10Be/ 9Be =1.5 10-14
10Be-10Be separation with degrader foil at 750 keV
10B
with addition magnet
Sample:
10Be/ 9Be =1.5 10-14
10Be9Be Background10-13
Scattered 10B
Total 10B suppression: ~1010
: (GIC: 106, Foil : ~ 104)
Background : ~10-15
best blanks : 10-15
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Ion Optics
Background from
other
isotopes
(masses)
1) Mass resolution1) Scattering
processes
2) Charge changing
processes
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Multi-isotope
facility1) High resolution
Gas counters
2) Degrader foilfor 10B-10Beseparation
3) 130-Magnet:-better massseparation,
-background reduction
4) Ion sourceModification:
- Higher currents- Better beam quality- Higher yield
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
10Be measurements
at 750 keV: 9 years
of research
Diplomarbeit
Von
Aronne Foresti
unter Betreuung vonProfessor
Martin Suter
an dem Institut für Ionenstrahlphysik
an der ETH Zürichwährend des
Sommers 2000
New Magnet
First measurements May 28,2009,7 μA BeO-
Background: ∼10-15
Yield: 10-12 %
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Compact multi-isotope AMS 600 kV compared to large AMS facilities)
Isotope
Beam
Background10-14
Trans/Yield
(%)
EnergyETHZ 5-8 MV
ETHZ
5-8 MV
ETHZ 5-8 MV
14C
C 0.2
0.2
42
60
0.44
30
26Al
Al 1
0.09
25
40
0.9
11
129I
I 10
2
9
8
2
30
239,240Pu
PuO
10
1-2 1.2
12-40
10Be
BeO
0.1<
0.015
11
35 0.75
20
36Cl Cl
1000
0.03
3 2
3.3
30 no
41Ca
CaF3
500 3
4 10
1.7
22 biomed
236U
UO
100
10
12
1-2 1.2 12-40
ETHZok
( )
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Smaller facilities (for radiocarbon)?
- Lower energies ?- Shorter Stripper ?- Smaller magnets ?- Smaller ion source ?
- Yield ?-
Background ?
-
Precision ?
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
0%
10%
20%
30%
40%
50%
60%
100 200 300 400 500 600 700Energy [keV]
Cha
rge
Sta t
e D
istri
b uti o
n
Φ(12 C
, v,
q) [%
]
q=1+
q=2+
q=3+
neutral
Charge State Distribution Model: Sayer
Φ
Charge State Distribution of 12C in Ar Gas
High yield of charge state 1+ between 200-500 keV !
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Design concept: small gas losses
high transmission high stability
good alignment demagnification of beam
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Design ideas for vacuum insulation
First schematic diagramM. Suter, 1999
United States Patent 5,661,299 Ken Purser August 26, 1997 Miniature AMS detector for Ultra-sensitive detection of individual carbon-14 and tritium atoms
„stripping four electrons from a fraction of the accelerated mass-14 ions “(1-
→2+,3+)
(
not 1+)
„In addition, using high vacuum insulation, pumping of gas molecules from the acceleration stages and the stripper region is greatly improved and access for maintenance is simplified
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
1)
Vacuum
insulated
2) Pumping
on ground
3) Conventional
power
supply
200 kV AMS facility
at Zurich
: New technologies
High Voltage feed through
Valve to controlstripper pressure Stripper gas line
stripper
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
All components
have
been
designed
at our
laboratory
Sample traylinear array
Detector
Ion source
14C13C12C
14C13C
12C
13CH
ESA
ESA
Page 39
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Ion Source development and sample preparation for 14C
-
Easy to operate-
Stable and High currents
- CO2 gas ion source
Arno Synal, Lukas Wacker, Tim Schulze-König
(ETH)
Matthias Ruff, Simon Fahrni, Uni. Berne
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Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Ion Beam
Physics, Annual
Report 2009
Page 41
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Sample preparation and ion sourcePretreatment
Cleaning Graphitization PressingIn holder
Ion source
Combustion
Sample
Automated combustion and graphitization simplifies
the sample preparation
CO2
GraphitizationElementalAnalyzer Trap
- Gas source reduces contamination for small samples
- Reduces work for sample preparation
- not for high precision (<0.4%) (limited currents)
Gas handling
Gas source
Laser ablation
Carbonates
Trapped Air
other
methods
Page 42
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
AMS-3Zurich1984
Developments of gas ion sources
GAS Neg.Ions
Page 43
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Gas feed operation
Gas supply capillary
Target positionTarget position
Gas supply capillary
Syringe
method
from
Erlangen
Page 45
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Combustion and transfer to gas ion source
Thesis: Matthias Ruff
Combustionin ElementalAnalyzer
Sample wheelwith 120 samples
Page 46
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Combustion in quartz tubes and automatic gas feed to ion source
Cracker changer
Page 47
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Source
performance
for
solids
and gasParameter Solid (large) Gas (small)
CO2
flow 2 µl/min (~1 µg C min−1)
C−
current 50 µA 10 µA
Ionisation
yield (5 -
20 %?) 5 –
10 %
Limit of detection 50 000 y 40 000 y
Typical precision (modern) 0.2 -
0.5 % 0.4 -
2 %
Sample size >100 µg C < 100 µg C
Measured samples in 2009 2400 500
Gas sources open many new applications : Compound specific studies
Page 48
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Compact AMS systems
NEC:
NEC:
HV
ETH/(PSI)Voltage:
0.5 MV 0.25 MV
1 MV
0.2 MV
Type:
Pelletron
single stage
Tandetron Power supply
Insulation: SF6
Air
SF6
VacuumTrans. %:
45
35-40
35
42
Background10-15: 2
2-4
3 2Precision %:
0.3 0.3
0.4
0.15-0.3
Isotopes:
14C(10Be,26Al)
14C
14C(10Be,26Al),
14C129I,(U),
Page 49
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
He-Stripping: a revolution for AMS at low energies
Advantages:1)
High yields at low energies (old story)
2)
Lower scattering losses (well known)3)
Reasonable destruction of molecules (surprisingly high!)
Disadvantages:1) Sparks!2) Less
pumping
!
3) Higher
gas flow
!
Page 50
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Radiocarbon dating below 200 keV
?
-
Small angle scattering losses? => light elements
-
Stripping yield? => light element ? Nobel gases?
-
Destruction of molecules ?
=> light element???
What is the best stripper gas?
Page 51
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Stripping
yield
of C on He
?
Page 52
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
SRIM-
Simulations Transmission for
12C in N2
,He (point source)
C in He (30 mrad)C in He (15 mrad)C in N2 (30 mrad)C in N2 (15 mrad)
15 mrad
30 mrad
Page 53
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Destruction
of CH and CH in He and N2
Tim Schulze-König Ph.D. Thesis (2010)
Page 54
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Stripping yield: 75 %Overall transmission:
35-40%
Background:
0.5 pMCReproducibility
(mod
C):
1.2 %
First results
of MS of 14C (Feasibility
study)
Also studied
-
Background sources-
Charge changing
cross sections
-
Beam
phase
space45 keV
Page 55
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Developing of Radiocarbon MS
Optimizing StripperOptimizing OpticsOptimizing PumpingOptimizing AperturesOptimizing Detector
Instrument for routine operationin 2-5 years
Page 56
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
He-stripping
of heavy
ions
Page 57
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Advantages of He stripping
for
U
37%
11%
3.3 x
1)
Higher
yield
at low
energies2)
Lower
scattering
losses
Page 58
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Folien
Mean charge
Gase
Width of distribution
Page 59
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Angular
distribution
for
U in He based
on SRIM Simulations
Thicknessμg/cm2 0.020.080.120.20.6
Scattering Limit:16.8 mrad = mHe /mU = 4/238
Page 60
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Charge State Distribution of U in He What
is
the
highest
yield
?
Wittkower
ETH
Estimate for themaximum: 46-48 %at 500-600 keV
Page 61
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Compact multi-isotope AMS 600 kV compared to large facilities)
Isotope
Beam
Background10-14
Trans/Yield
(%)
EnergyETHZ 5-8 MV
ETHZ
5-8 MV
ETHZ 5-8 MV
14C
C 0.2
0.2
42
60
0.44
30
26Al
Al 1
0.09
25
40
0.9
11
129I
I 10
2
9
8
2
30
239,240Pu
PuO
10
1-2 1.2
12-40
10Be
BeO
0.1<
0.015
11
35 0.75
20
36Cl Cl
1000
0.03
3 2
3.3
30 no
41Ca
CaF3
500 3
4 10
1.7
22 biomed
236U
UO
100
10
12
1-2 1.2 12-40
ETHZok
( )45
20(3+)
15
30
36
35
Page 62
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Disadvantages
of He
High voltage discharge
tube
Sparks depend on tube:-
Length
l-
Voltage
V- Diameter d- Material-
Shape
gas flow:Less pumping
-No Cryopumps
Turbopumps
Conductance in molecular flow region:
C ~ M -1/2
He/Ar
= 3.3
-More gas flows thoughthe accelerator tubes
-Enrichment of heavy contamination (leaks!)
Page 63
Ion Beam Physics
Martin SuterMartin SuterSeminar April 12 / 2011, ANSTO
Future of measurements of long-lived radioisotopes Road map for 5 years
14C: MS : Instrument for routine measurements
10Be,26Al,41Ca,129I,236U,Pu : Compact high performance instrument (0.1-1 MV?)
36Cl: Combination of reaction cell with AMS (Ottawa, Vienna?)
Other methods (Laser)?
32Si, 41Ca, 53Mn, 59Ni, 60Fe …. with large AMS facilities (6-14 MV?)
14C:
Gas ion sources routinely used, simpler sample preparation
Physics knowledge and new technologies are needed !
Good scientists and technical staff is relevant !