from large ams facilities to table size instruments supplies electronics ams-12-topic: technical...

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

Ion Beam Physics


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

Ion Beam Physics


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

Ion Beam Physics


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

Ion Beam Physics


Sample Statistics

LIP

~7500in 2010

with

3 accelerators, 6 MV, 550 kV,

200kV

Ion Beam Physics


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

Ion Beam Physics


My interest and my dreams

-Smaller-Cheaper-More reliable-High performance-Universal

Ion Beam Physics


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

http://www.apple.com/fr/ipad/features/

http://www.apple.com/fr/ipad/features/

Ion Beam Physics


Moore‘s Law

Ion Beam Physics


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

Ion Beam Physics


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)

Ion Beam Physics


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)

Ion Beam Physics


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

Ion Beam Physics


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

€

Ion Beam Physics


Charge state

yield

and accelerator

size

q > 2 molecules

unstable

q < 3 molecules

stable

4+3+1+ 2+

Carbon

in Ar

Ion Beam Physics


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

Ion Beam Physics


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

Ion Beam Physics


Further

developments

: 2000-2010

Smaller

instrumentsfor

radiocarben

Compact multi isotopeInstruments:10Be, 26Al, 41Ca, 129I, 236U, 239,240

Pu

Ion Beam Physics


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

Ion Beam Physics


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

Ion Beam Physics


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+

Ion Beam Physics


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

Ion Beam Physics


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

Ion Beam Physics


Energy

resolution

for

light ions

(m <14, E=0.1-2 MeV)

Electronic noiseis

relevant !

From

Arnold Müller

Ion Beam Physics


Gas detectors at low energies ?U (E = 1.2 MeV) is stopped in 70 μg/cm2 Polypropylene!

Simulation with SRIM program

Ion Beam Physics


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

!

Ion Beam Physics


-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

!

Ion Beam Physics


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

Ion Beam Physics


Ion Optics

Background from

other

isotopes

(masses)

1) Mass resolution1) Scattering

processes

2) Charge changing

processes

Ion Beam Physics


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

Ion Beam Physics


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 %

Ion Beam Physics


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

( )

Ion Beam Physics


Smaller facilities (for radiocarbon)?

- Lower energies ?- Shorter Stripper ?- Smaller magnets ?- Smaller ion source ?

- Yield ?-

Background ?

-

Precision ?

Ion Beam Physics


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 !

Ion Beam Physics


Design concept: small gas losses

high transmission high stability

good alignment demagnification of beam

Ion Beam Physics


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

Ion Beam Physics


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

Ion Beam Physics


All components

have

been

designed

at our

laboratory

Sample traylinear array

Detector

Ion source

14C13C12C

14C13C

12C

13CH

ESA

ESA

Ion Beam Physics


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

Ion Beam Physics


Ion Beam

Physics, Annual

Report 2009

Ion Beam Physics


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

Ion Beam Physics


AMS-3Zurich1984

Developments of gas ion sources

GAS Neg.Ions

Ion Beam Physics


Gas feed operation

Gas supply capillary

Target positionTarget position

Gas supply capillary

Syringe

method

from

Erlangen

Ion Beam Physics


Ion Beam Physics


Combustion and transfer to gas ion source

Thesis: Matthias Ruff

Combustionin ElementalAnalyzer

Sample wheelwith 120 samples

Ion Beam Physics


Combustion in quartz tubes and automatic gas feed to ion source

Cracker changer

Ion Beam Physics


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

Ion Beam Physics


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),

Ion Beam Physics


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

!

Ion Beam Physics


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?

Ion Beam Physics


Stripping

yield

of C on He

?

Ion Beam Physics


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

Ion Beam Physics


Destruction

of CH and CH in He and N2

Tim Schulze-König Ph.D. Thesis (2010)

Ion Beam Physics


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

Ion Beam Physics


Developing of Radiocarbon MS

Optimizing StripperOptimizing OpticsOptimizing PumpingOptimizing AperturesOptimizing Detector

Instrument for routine operationin 2-5 years

Ion Beam Physics


He-stripping

of heavy

ions

Ion Beam Physics


Advantages of He stripping

for

U

37%

11%

3.3 x

1)

Higher

yield

at low

energies2)

Lower

scattering

losses

Ion Beam Physics


Folien

Mean charge

Gase

Width of distribution

Ion Beam Physics


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

Ion Beam Physics


Charge State Distribution of U in He What

is

the

highest

yield

?

Wittkower

ETH

Estimate for themaximum: 46-48 %at 500-600 keV

Ion Beam Physics


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

Ion Beam Physics


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!)

Ion Beam Physics


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 !

Ion Beam Physics


Thank You !