national technical university of athens department of physics nra studies at the inp tandem: present...

NATIONAL TECHNICAL UNIVERSITY OF ATHENSNATIONAL TECHNICAL UNIVERSITY OF ATHENSDEPARTMENT OF PHYSICSDEPARTMENT OF PHYSICS

NRA studies at the INP Tandem: NRA studies at the INP Tandem: PPresent status and resent status and perspectivesperspectives

M. KokkorisM. Kokkoris11, , C. T. PapadopoulosC. T. Papadopoulos11,, R. Vlastou R. Vlastou11, P. Misailides, P. Misailides22, , S. HarissopulosS. Harissopulos33, A. Lagoyannis, A. Lagoyannis33

1 Department of Physics, National Technical University of Athens, Zografou Campus 157 80, Athens, Greece

2 Department of Chemistry, Aristotle University, GR-54006, Thessaloniki, Greece

3 Institute of Nuclear Physics, TANDEM Accelerator, N.C.S.R. ‘Demokritos’, Aghia Paraskevi 153 10, Athens, Greece

AcknowledgementsAcknowledgementsThis project is co-funded by the European Social Fund (75%) and National Resources This project is co-funded by the European Social Fund (75%) and National Resources (25 %) - (EPEAEK - II) - PYTHAGORAS II, NTUA (25 %) - (EPEAEK - II) - PYTHAGORAS II, NTUA ΠΕΒΕ ΠΕΒΕ ‘Karatheodwris’, and is being ‘Karatheodwris’, and is being carried out in collaboration with the IAEA, Vienna.carried out in collaboration with the IAEA, Vienna.


TOPICS:TOPICS:

1.1. BRIEF INTRODUCTION ON IBA AND NRABRIEF INTRODUCTION ON IBA AND NRA

2.2. NRA vs NBSNRA vs NBS

3.3. CURRENT STATUS (IBANDL) AND EFFORTSCURRENT STATUS (IBANDL) AND EFFORTS

4.4. WORK SUBMITTED BY OUR GROUPWORK SUBMITTED BY OUR GROUP::

A) EXPERIMENTAL SETUPA) EXPERIMENTAL SETUP

B) ANALYSIS AND DISCUSSIONB) ANALYSIS AND DISCUSSION

5.5. REVIEW OF RECENT CONTRIBUTIONSREVIEW OF RECENT CONTRIBUTIONS

6.6. CONCLUSIONS / FUTURE PERSPECTIVESCONCLUSIONS / FUTURE PERSPECTIVES


What is IBA?What is IBA?

The term corresponds to a series of analytical techniques for material The term corresponds to a series of analytical techniques for material studies. studies. Ion Beam Analysis (IBA) is based on the interaction, at both the Ion Beam Analysis (IBA) is based on the interaction, at both the atomic andatomic and the nuclear level, between accelerated charged particles and the the nuclear level, between accelerated charged particles and the bombardedbombarded material. This can lead to the emission ofmaterial. This can lead to the emission of particles or radiation particles or radiation whose energy is characteristic of the elements which constitute the sample whose energy is characteristic of the elements which constitute the sample material.material.

IBA PROFILING TECHNIQUES:IBA PROFILING TECHNIQUES:• Rutherford Backscattering Spectroscopy / Nuclear Backscattering Spectroscopy (RBS / NBS) / Channeling

• Elastic Recoil Detection Analysis (ERDA)

• Nuclear Reaction Analysis (standard NRA and resonant-PIGE)

NON-PROFILING:NON-PROFILING:• Charged Particle Activation Analysis (CPAA), Particle Induced X/γ-Ray Emission (PIXE/PIGE)

• Neutron Activation Analysis (NAA), Secondary Ion Mass Spectroscopy (SIMS)

Most popular orientation for small electrostatic accelerators worldwide (>95%)Most popular orientation for small electrostatic accelerators worldwide (>95%)


NRA:NRA: Well – established nowadays as one of the principal IBA Well – established nowadays as one of the principal IBA techniques for accurate quantitative depth profiling of light elements techniques for accurate quantitative depth profiling of light elements in complex matrices.in complex matrices.

Based on the use of nuclear reactions. More frequently used:Based on the use of nuclear reactions. More frequently used:

1.1. (p,(p,α)α):: Low Q-value ( Low Q-value (66Li, Li, 99Be, Be, 1010B, B, 2727Al) and high Q-value (Al) and high Q-value (77Li, Li, 1111B, B, 1818O, O, 1919F, F, 2323Na, Na, 3131P). No absorber foil can be applied. Highly selective. P). No absorber foil can be applied. Highly selective.

2.2. ((αα,p):,p): Very few elements have positive Q-values ( Very few elements have positive Q-values (10,1110,11B, B, 1919F, F, 2323Na, Na, 2727Al, Al, 3131P, P, 3535Cl) thus the background is severely reduced. Cross sections are high Cl) thus the background is severely reduced. Cross sections are high enough only at high beam energies.enough only at high beam energies.

3.3. (d,p) and (d,(d,p) and (d,αα):): Almost all light isotopes have high positive Q-values. They Almost all light isotopes have high positive Q-values. They permit simultaneous analysis of many light elements in complex matrices permit simultaneous analysis of many light elements in complex matrices (e.g. C, O, N, B, S etc.) at the expense of peak overlaps or background (e.g. C, O, N, B, S etc.) at the expense of peak overlaps or background interference in some cases. Require very low beam energies. Radiation interference in some cases. Require very low beam energies. Radiation safety precautions are mandatory because the (d,n) reaction channel is safety precautions are mandatory because the (d,n) reaction channel is almost always open.almost always open.

4.4. Less frequently used: (p,d), (p,Less frequently used: (p,d), (p,33He), He), 33He-NRAHe-NRA


NRA Characteristics:NRA Characteristics:

POSITIVEPOSITIVE

High isotopic selectivity Enhanced sensitivity for many elements Capability of least – destructive depth profiling with nanometer resolution The matrix is not a critical factor as in other IBA techniques Clear isolated peaks with practically no background is usually the case If the deuteron beam is adopted, one can achieve simultaneous analysis of most of the main light elements (C, O, N, F, B, Li)

NEGATIVENEGATIVE

Not many / or discrepant cross sections available in literature, usually with high experimental errors Theoretical evaluation is missing Usually time-consuming studies, while radiation safety is sometimes an issue (d-NRA) Not all the elements present low enough MDLs (typical sensitivities: 1:104 in atomic proportion)


NRA NRA vsvs NBSNBS – Which is preferable? – Which is preferable?

• Data acquisition is much faster in the case of NBS.Data acquisition is much faster in the case of NBS.

• Depth profiling is more accurate due to the lower energies Depth profiling is more accurate due to the lower energies (enhanced stopping power) generally involved (e.g. oxygen (enhanced stopping power) generally involved (e.g. oxygen profiling using the 3.05 resonance in profiling using the 3.05 resonance in 1616O(O(α,α) α,α) rather than the rather than the 1616O(d,pO(d,p00,p,p11,,αα00) ) reactions).reactions).

• Significantly more differential cross section data are available, Significantly more differential cross section data are available, over a wide range of beam energies and detector angles.over a wide range of beam energies and detector angles.

• For the most important elements with resonances in elastic For the most important elements with resonances in elastic scattering evaluated differential cross section data already exist.scattering evaluated differential cross section data already exist.

Nevertheless NRA is still the only technique that can provide Nevertheless NRA is still the only technique that can provide accurate results for the profiling of light elements when the accurate results for the profiling of light elements when the matrix is complex.matrix is complex.


The present situation of d-NRA:The present situation of d-NRA:

The theoretical complexities of d-NRA:The theoretical complexities of d-NRA:

Theta=165.00 M. Kokkoris et al. NIM B (2006)

FavorableFavorablecasecase

SevereSevereproblemsproblems

1.1. Coexistence of many open reaction channels.Coexistence of many open reaction channels.

2.2. Electric charge asymmetry of the deuteron.Electric charge asymmetry of the deuteron.

3.3. Multiple projectile-target exchange of nucleons.Multiple projectile-target exchange of nucleons.

4.4. Existence of direct exchange processes (e.g. knock-out, stripping).Existence of direct exchange processes (e.g. knock-out, stripping).

5.5. Overlapping resonances.Overlapping resonances.


EXPERIMENTAL SETUP:EXPERIMENTAL SETUP:

5.5 MV HV Tandem 5.5 MV HV Tandem Accelerator, N.C.S.R. Accelerator, N.C.S.R. ‘Demokritos’‘Demokritos’

Motor driven goniometerMotor driven goniometerGreat angular accuracy Great angular accuracy (0.01 deg.)(0.01 deg.)

* A.Pakou et al. , Phys. Rev. Lett. 90 (2003) * A.Pakou et al. , Phys. Rev. Lett. 90 (2003)

up to 8 single SSB, associated with standard NIM/CAMAC electronics. up to 8 single SSB, associated with standard NIM/CAMAC electronics. Upgrading is scheduled. Upgrading is scheduled.

The current setup allows for target cooling with water or methanol through a The current setup allows for target cooling with water or methanol through a closed circuit during acquisitionclosed circuit during acquisition

Voltage suppression up to 1000 V on the collimator, target and/or faraday Voltage suppression up to 1000 V on the collimator, target and/or faraday cup.cup.

RESULTS FOR d+RESULTS FOR d+1010B:B:

0 200 400 600 800 10000

500

1000

1500

2000

2500

3000

CO

UN

TS

CHANNEL

Ed, lab

=1419 keV, lab

=1600

P0

0

P1

P2

P3

P45

P6

16O

(d, p

0)17O

12C(d, p

0)13C

0

P0

P1

P2P

3

800 1000 1200 1400 1600 1800 2000

0.0

0.8

1.6

2.4

3.2

4.0

d/d

(mb/

sr)

Ed, lab

(keV)

150o

p0

p1

p2

p3

p45

p6

800 1000 1200 1400 1600 1800 2000

0.1

0.2

0.3170o

Ed, lab

(keV)

d/

d

(mb

/sr)

0

More than ~2000 differential cross section More than ~2000 differential cross section values have been determined for 8 different values have been determined for 8 different detector angles (at 5º intervals), in beam detector angles (at 5º intervals), in beam energy steps of ~25 keVenergy steps of ~25 keV (900-2000 (900-2000 keV).keV).

Results already at IBANDL, (NIM B 2007, Results already at IBANDL, (NIM B 2007, Parts A and B).Parts A and B).

INTERESTING POINTS – PROBLEMS:INTERESTING POINTS – PROBLEMS:

800 1000 1200 1400 1600 1800 2000

0.1

0.2

0.3

0.4

0.5

0.6155o

Ed, lab

(keV)

d/

d

(mb

/sr)

0, present work

Data from Purser (1963) at 156o

300 400 500 600 700 800 9000

100

200

300

400

500

600

1?

p2

p3

p1

0

Experimental spectrum (with absorber foil)

SIMNRA results (with data from Purser for

1)

Yie

ld

Channel

=155o, Ed, lab

=1344 keV

p0

Thick target smears Thick target smears out the resonance out the resonance

structurestructure

αα11 does not exist! A does not exist! A

note should be made note should be made at IBANDLat IBANDL

INTERESTING POINTS – PROBLEMS:INTERESTING POINTS – PROBLEMS: Very strong and unknown resonance structure (Very strong and unknown resonance structure (3434Cl level scheme is missing!)Cl level scheme is missing!)

Disagreement with Healy et al. NIM B (1998) data from thick target yield Disagreement with Healy et al. NIM B (1998) data from thick target yield deconvolution, very good agreement with digitized data from publication!deconvolution, very good agreement with digitized data from publication!

More than ~500 new data points at IBANDLMore than ~500 new data points at IBANDL

NIM B 2008NIM B 2008

1900 2000 2100 2200 2300 2400 2500 2600

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

32S(d,p7)33S

140o

150o

160o

170o

d/

d (

mb

/sr)

Ed,lab

(keV)

1900 2000 2100 2200 2300 2400 2500 2600 27000.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Ed,lab

(keV)

Present work Healy et al. (thin target) Healy et al. (thick target) Saad et al.

d/d

(mb/

sr)

RESULTS FOR d+RESULTS FOR d+3232S:S:


RESULTS FOR d+RESULTS FOR d+1111B:B:

900 1000 1100 12000.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

140o

150o

160o

170o

d/

d

(mb

/sr)

Ed, lab

(keV)

11B(d,) Reaction

900 1000 1100 1200

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Ed, lab

(keV)

d/

d

(mb

/sr)

11B(d,) Reaction

140o

150o

160o

170o

900 1000 1100 1200

1.0

1.5

2.0

2.5

3.0

3.5

d/

d

(mb

/sr)

Ed, lab

(keV)

140o

150o

160o

170o

11B(d,p0) Reaction

INTERESTING POINTS:INTERESTING POINTS: Very smooth excitation curves – weak angular Very smooth excitation curves – weak angular dependencedependence

More than ~200 new data points for IBANDLMore than ~200 new data points for IBANDL

NIM B 2009 (in press)NIM B 2009 (in press)


Selected recent important works in the field of d-NRA:Selected recent important works in the field of d-NRA:

d-NRA of low-abundance d-NRA of low-abundance isotopes, such as isotopes, such as 1313C (1.1% in C (1.1% in natnatC) at 165C) at 165oo and 135 and 135oo

J.L. Colaux, T. Thomé and G. Terwagne, Nucl. Instrm. Meth. B254 (2007) 25-29

Analysis of the most important Analysis of the most important levels of a top NRA candidate, levels of a top NRA candidate, 1414N, at 150N, at 150oo. Also contributions . Also contributions for for 2727Al.Al.

S. Pellegrino et al. NIM B 219-220 (2004) 140

* * Many PIGE studies as well (Many PIGE studies as well (Z.Elekes et al. Nucl. Instr. & Meth. B168Z.Elekes et al. Nucl. Instr. & Meth. B168, , 20002000,, 305 305 etc.) etc.)


CONCLUSIONSCONCLUSIONS / FUTURE PERSPECTIVES: / FUTURE PERSPECTIVES:

(a)(a) d-NRA studies are very promising. Many open questions: Angular d-NRA studies are very promising. Many open questions: Angular distribution at forward angles? distribution at forward angles?

(b)(b) Study of Study of 1414N in progress using the same technique. Studies of the N in progress using the same technique. Studies of the d+d+6,76,7Li systems are currently carried out.Li systems are currently carried out.

(c)(c) Time-consuming studies affect quick quantification of the results.Time-consuming studies affect quick quantification of the results.

(d)(d) In the next phase we also need to proceed to (p,In the next phase we also need to proceed to (p,α) α) reaction studies reaction studies on on 6,76,7Li, Li, 10,1110,11B, B, 1919F and F and 2323Na.Na.

(e)(e) The theoretical evaluation – if accomplished – will considerably The theoretical evaluation – if accomplished – will considerably enhance NRA capabilities.enhance NRA capabilities.

(f)(f) As far as NBS is concerned, (d,dAs far as NBS is concerned, (d,d00) ) onon 6,76,7Li, and Li, and 10,1110,11BB and (and (α,αα,α00)) on on 3131P, P, natnatS, S, 3939K and K and natnatCa are scheduled in a 5-year plan in order to facilitate Ca are scheduled in a 5-year plan in order to facilitate the data evaluation process.the data evaluation process.

To Joseph Salomon (AGLAE, Paris)…To Joseph Salomon (AGLAE, Paris)…

Local Local Organizing Organizing Committee:Committee:

P. Misaelides, F. NoliP. Misaelides, F. Noli

Aristotle University, ThessalonikiAristotle University, Thessaloniki

M. Kokkoris, R. VlastouM. Kokkoris, R. Vlastou

National Technical University of AthensNational Technical University of Athens

A. G. Karydas, A. Lagoyannis, S. HarissopulosA. G. Karydas, A. Lagoyannis, S. Harissopulos

N.C.S.R. ‘Demokritos’N.C.S.R. ‘Demokritos’

A. Godelitsas, A. KarabarbounisA. Godelitsas, A. Karabarbounis

University of AthensUniversity of Athens

1010thth EEuropeanuropean CConferenceonference onon AAcceleratorscceleratorsin in AAppliedpplied RResearchesearch andand TTechnologyechnology

to be held in Athens, Greece,to be held in Athens, Greece,

12-17 September 201012-17 September 2010

national technical university of athens department of physics nra studies at the inp tandem: present...

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