NATIONAL TECHNICAL UNIVERSITY OF ATHENS DEPARTMENT OF PHYSICS

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

A Detailed Study of the A Detailed Study of the 10,1110,11B(d,B(d,αα) and ) and 10,1110,11B(d,p)B(d,p) Reactions Reactions at Detector Angles between 135 and 170 degrees for the at Detector Angles between 135 and 170 degrees for the

Energy Range EEnergy Range Ed,Labd,Lab=900-2000 keV=900-2000 keV

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


TOPICS:TOPICS:

1.1. MOTIVATIONMOTIVATION

2.2. EXPERIMENTAL SETUP AND PROCEDUREEXPERIMENTAL SETUP AND PROCEDURE

3.3. ANALYSIS AND DISCUSSION ANALYSIS AND DISCUSSION

4.4. CONCLUSIONSCONCLUSIONS

5.5. FUTURE PERSPECTIVESFUTURE PERSPECTIVES


MOTIVATION:MOTIVATION:

1. Nuclear Reaction Analysis (NRA) is well established as one of the primary methods in ion beam analysis of light elements in complex matrices. Other techniques are RBS and NBS. Main NRA advantages: (a) high isotopic selectivity, (b) good sensitivity for many nuclides (c) least destructive depth profiling, (d) accurate quantitative analysis and (e) possible simultaneous analysis of multiple light elements.

Main Problem: Lack of differential cross section data for a variety of beam-target combinations in literature

Ion Beam Analysis Nuclear Data Library: : IBANDLIBANDL

Analytical algorithms e.g. SIMNRA, RUMP etc.


2. The ‘boron problemboron problem’: RBS is weak, NBS can be applied only in certain cases (no other light elements present, no high-Z matrix, very case-specific measurements):

ExperimentalSimulatedB Si

Channel460440420400380360340320300280260240220200180160140120100806040200

Co

un

ts

60,000

58,00056,000

54,00052,000

50,00048,000

46,000

44,00042,000

40,00038,000

36,00034,000

32,000

30,00028,000

26,00024,000

22,00020,000

18,00016,000

14,000

12,00010,000

8,0006,000

4,0002,000

0

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200

Energy [keV]

ExperimentalSimulatedB O

Channel62060058056054052050048046044042040038036034032030028026024022020018016014012010080604020

Co

un

ts

6,000

5,8005,600

5,4005,200

5,0004,800

4,600

4,4004,200

4,0003,800

3,6003,400

3,200

3,0002,800

2,6002,400

2,2002,000

1,8001,600

1,400

1,2001,000

800600

400200

0

100 200 300 400 500 600 700 800 900 1000 1100 1200

Energy [keV]

5% B in Si5% B in SiEEpp=2.6 MeV=2.6 MeV EEαα=2.=2.99 MeV MeV

Overlapping Overlapping resonances resonances

(borax)(borax)

PIGE + resonant PIGE not promising, NRA reactions proposed so far: PIGE + resonant PIGE not promising, NRA reactions proposed so far: (p,(p,α), α), ((αα,p), (d,,p), (d,α)α): Very limited literature, cross sections of the order of : Very limited literature, cross sections of the order of ~1-10 mb/ster~1-10 mb/ster


3. Theoretical considerations:

1. Reaction Mechanism involved.1. Reaction Mechanism involved.

2. Broad resonances with overlapping widths.2. Broad resonances with overlapping widths.

3. Effect of electric charge asymmetry of the deuteron.3. Effect of electric charge asymmetry of the deuteron.

3. Multiple open channels, (d,d), (d,p), (d,3. Multiple open channels, (d,d), (d,p), (d,α), α), (d,n)!(d,n)!

4. 4. 88Be breakup channel.Be breakup channel.

Great possible technological implications (plasma physics, Great possible technological implications (plasma physics, semiconductor industry, boron nitride films, environmental semiconductor industry, boron nitride films, environmental applications etc.)applications etc.)

Proposal:Proposal: Implementation of the d-induced reactions in boron isotopes Implementation of the d-induced reactions in boron isotopes which are also sensitive to many light elements (which are also sensitive to many light elements (1616O, O, 1212C, C, 1414N, N, 1919F) and can F) and can be applied in any accelerator setup (low beam energies required)be applied in any accelerator setup (low beam energies required)


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)

8-16 single SSB, or 4-8 8-16 single SSB, or 4-8 ΔΔE/E solid state detector telescopes for particle E/E solid state detector telescopes for particle identification (depending on the reaction studied), associated with standard identification (depending on the reaction studied), associated with standard NIM or CAMAC electronics. Upgrading is scheduled. NIM or CAMAC electronics. 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.


EXPERIMENTAL PROCEDURE:EXPERIMENTAL PROCEDURE:

(a) Preparation/testing of the targets.

(b) Spectra acquisition (45 energies between 900 and 2000 keV, 25 keV step) at variable charge, depending on statistics for both reactions.

(c) Determination of the solid angle using an uncalibrated Am-Pu-Cm α-source + RBS spectra. Uncertainty in Q*Ω < 2.5(4.3)% due to voltage suppression and effective faraday cup (tested with Al and Au foils in the past).

(d) Peak analysis using two different algorithms to account for the bias error (σ Yield(exp) <1% using Spectr and Origin).

(e) Error evaluation: 1. Monitoring of the changes in the foil thickness (A in at/cm2) by sputtering and accuracy in the energy due to carbon buildup (despite the two liquid nitrogen traps).

(f) Measurements with and without absorber foils.


ANALYSIS AND DISCUSSION:ANALYSIS AND DISCUSSION:

ReactionReaction Q-value (keV)Q-value (keV) EEx,lab,max x,lab,max (keV)(keV) Excitation energy range Excitation energy range (keV)(keV)

1010B(d,α)B(d,α)88Be (2α)Be (2α) 17820 (17914)17820 (17914) 1128511285 25936-26852 (25936-26852 (1212CC**))

1010B(d,p)B(d,p)1111BB 92299229 92239223 25936-26852 (25936-26852 (1212CC**))

1111B(d,α)B(d,α)99BeBe 80318031 56025602 19439-20370 (19439-20370 (1313CC**))

1111B(d,p)B(d,p)1212BB 11461146 22622262 19439-20370 (19439-20370 (1313CC**))


The excitation energy range reported, is important for the study The excitation energy range reported, is important for the study of the influence of the resonance mechanism. The only strong of the influence of the resonance mechanism. The only strong influence reported in the past concerns the influence reported in the past concerns the 1111B(d,B(d,αα))99Be reaction at Be reaction at EEdd=1.85 MeV. Broad maxima have also been reported concerning =1.85 MeV. Broad maxima have also been reported concerning

the the 1010B(d,B(d,αα))88Be reaction around EBe reaction around Edd=1 and 2 MeV. The =1 and 2 MeV. The 10,1110,11B(d,p) B(d,p)

reaction cross sections on the other hand, seem to vary smoothly reaction cross sections on the other hand, seem to vary smoothly with energy (for the Ewith energy (for the Edd range under study). range under study).

CIRE (GANIL) has been used for 2 or 3-body kinematics.CIRE (GANIL) has been used for 2 or 3-body kinematics.

1010B enriched targets exist (94%) on Ta backings, d = 21.5B enriched targets exist (94%) on Ta backings, d = 21.50.5 0.5 μμg/cmg/cm22,, 1111B or B or natnatB ones not yet (on thin Au foil?)B ones not yet (on thin Au foil?)

αα++1010BB

αα++88BeBe

p+p+1111BB

n+n+1111CC

1212CC

αα++1111BB

1313CC

αα++99BeBe

p+p+1212BB

n+n+1212CC


(a) The study of the deuteron induced reactions in the boron isotopes will proceed via separate stages (for 10B and 11B respectively) .

(b) With the exception of the 11B(d,p)12B reaction, all the other reactions seem to be well suited for IBA applications.

(c) The study of the 10B(d,p)11B reaction at backscattering angles might enhance NRA capabilities.

FIRST EXPECTED DETAILED EXPERIMENTAL STUDY OF THESE FIRST EXPECTED DETAILED EXPERIMENTAL STUDY OF THESE REACTIONS FOR NRA PURPOSES.REACTIONS FOR NRA PURPOSES.

CONCLUSIONS:CONCLUSIONS:


FUTURE PERSPECTIVES:FUTURE PERSPECTIVES:

(a)(a) Many open questions: Angular distribution at forward angles? Many open questions: Angular distribution at forward angles?

(b)(b)What is the maximum analyzing depth? All the (d,p) and (d,What is the maximum analyzing depth? All the (d,p) and (d,αα) ) reactions in light elements also need to be studied. Study of reactions in light elements also need to be studied. Study of 1414N, N, 1919F F as well as as well as 3232SS,, in progress using the same technique.in progress using the same technique.

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

(d)(d) Completing the Completing the 1212C(d,pC(d,p11,p,p22,p,p33) analysis, after the ) analysis, after the natnatC(d,dC(d,d00) and ) and 1212C(d,pC(d,p00) in the same energy and angular range.) in the same energy and angular range.

(d) Need for experimental data! – Extensive program scheduled for 3 (d) Need for experimental data! – Extensive program scheduled for 3 years in order to supply the scientific community with benchmark years in order to supply the scientific community with benchmark data suitable for technological applications.data suitable for technological applications.

NATIONAL TECHNICAL UNIVERSITY OF ATHENS DEPARTMENT OF PHYSICS

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