Tandem Accelerator Research Articles

Development towards 53Mn Accelerator Mass Spectrometry capabilities at the University of Notre Dame

Accelerator Mass Spectrometry (AMS) with 53Mn has geological applications as a chronometer for exposure and burial times for discontinuously deposited sediments. It has also been used to search for evidence of recent supernovae events, and proposed as a proxy to monitor the variation in the galactic cosmic ray spectrum over time. The current sensitivity limit amongst active facilities is 53Mn/ 55Mn = 3×10−13 while a sensitivity of 53Mn/ 55Mn = 1×10−13 is necessary to fully exploit 53Mn’s capabilities. At the University of Notre Dame’s Nuclear Science Laboratory (NSL), a 10 MV tandem accelerator and a Browne–Buechner Spectrograph operated as a gas-filled magnet were used to separate 53Mn from 53Cr. Samples covering ranges of 53Mn/ 55Mn = 10−10−10−8 were measured for the first time at the NSL using various settings resulting in a background level of 53Mn/ 55Mn =6.2(3)×10−11. Analysis of the results, descriptions of experimental settings, and further explorations will be presented in this paper.

Cross Section Measurements and Theoretical Study of the 174,176Hf(n,2n)173,175Hf Reactions

Experimental cross section measurements for the 176Hf(n,2n)175Hf and 174Hf(n,2n)173Hf reactions were carried out, using the activation technique. The neutron beam energy in the range of 15.3-20.3 MeV was produced via the 3H(d,n)4He reaction at the 5.5 MeV Tandem Van de Graaf accelerator laboratory of NCSR “Demokritos”. A thin metallic foil of natural Hf was used, while for the determination of the neutron flux at the target position, reference foils of Al were placed at the front and back of the Hf target. The irradiations were continuous for ~24-48 hours, leading to a total neutron fluence of 1010-1011 n/cm2 and a BF3 detector was used for monitoring the neutron flux during the irradiations. After the end of each irradiation, the activity of the Hf target and the Al reference foils were measured off-line by two HPGe detectors. The 176Hf(n,2n)175Hf reaction has been corrected for the contribution of the 177Hf(n,3n)175Hf and 174Hf(n,γ)175Hf reactions. Statistical model calculations based on the Hauser-Feshbach theory have also been performed using the EMPIRE 3.2.3 code. The predictions have been compared with the data of the present work as well as with data from literature.

Cross section measurements of low-energy charged particle induced reactions using moderated neutron counter arrays

A high-and-flat efficiency moderated neutron detection array of 3He counters has been recently developed for photoneutron cross section measurements at the future ELI-NP gamma-ray beam source. We have designed a three rings geometry of 31 counters with a ˜37% efficiency flat within 5% in the 10 keV to 5 MeV neutron energy interval. A commissioning experiment was performed using proton beams delivered by the 9 MV Tandem accelerator of IFIN-HH. We measured the neutron production cross sections for proton induced reactions on nat Cu and 27Al. The (p, xn) reactions on nat Cu were investigated in the 4.5 MeV to 14 MeV proton energy range with 250 keV steps, using pulsed and continuous proton beams. The low energy measurements below 10 MeV served to validate the detection efficiency calibration against well-known natCu(p, n) cross sections. The 27Al(p, n) reaction was investigated in the 5.8 MeV to 6.75 MeV energy range with 5 keV steps. Preliminary cross section results are here compared with preceding data.

Results of total cross-section measurements of the 87Rb(p,γ)88Sr reaction

The existence of a set of stable proton-rich nuclei - the p nuclei - cannot be explained via neutron-capture reactions. Therefore, another mechanism has to exist in order to explain their origin, the most probable, especially at high masses, being photodisintegration reactions. This gives rise to the γ process. Since most photodisintegration reactions involved in the process are not experimentally accessible, reliable statistical model calculations are needed to predict cross sections and reaction rates. To improve these calculations nuclear input parameters need to be constrained and a large experimental database is needed. Via comparison of experimental data to theoretical predictions different models can be tested and constrained. In order to study the 87Rb(p,γ)88Sr reaction, for which previously no experimental data have been available, an in-beam experiment at at the University of Cologne’s high-efficiency HPGe γ-ray spectrometer HORUS was performed. Proton beams with energies between Ep = 2000 to 5000 keV reaching deep into the Gamow window of the reaction were provided by the 10 MV FN Tandem accelerator. Cross-section values at six proton beam energies were determined. The experimental results are in good agreement with statistical model calculations. The obtained results are the first experimental cross-section values for the87Rb(p,γ)88Sr reaction and help to constrain the nuclear physics input for statistical model calculations.

Activation Cross Section Measurement of the (n,2n) Reaction on 203Tl

The aim of the present work was to study the cross-section of the (n,2n) reaction on 203Tl, by irradiating a natural TlCl pellet target with monoenergetic neutron beams at 16.4, 18.9 and 19.3 MeV. The cross section of the 203Tl(n,2n)202Tl reaction was measured via the activation method, with respect to the 197Au(n,2n)196Au and 27Al(n,α)24Na reference reactions. At the same time, the 203Tl(n,3n)201Tl was also measured at 18.9 and 19.3 MeV. The monoenergetic neutron beams were generated at the 5.5 MV Tandem accelerator of NCSR “Demokritos”, using the 3H(d,n)4He reaction. In addition, theoretical calculations with the EMPIRE code have been performed, in order to find a suitable model for the description of the experimental data of the present work along with the data from literature.

JRC MONNET – the intense fast-neutron source for fundamental and application-driven research

MONNET is a fast-neutron source based on a 3.5 MV tandem accelerator, located at the Geel (BE) site of the Joint esearch Centre. It became operational in 2020. MONNET may deliver intense neutron beams in the energy range from 30 keV to 10.1 MeV and from 12.8 MeV to 24 MeV. Neutrons are generated by means of nuclear reactions in the target material (e.g. protons or deuterons on lithium-7, tritium or deuterium targets). MONNET delivers a neutron flux of up to 109 n/sr/s, depending on the producing reaction and the neutron energy. Neutron beams are essentially mono-energetic (∆En/En < 6% with En > 300 keV). The accelerator may also be used with proton and deuteron beams. Alpha beams will be offered soon. Photon beams are possible and presently under investigation. The research program ranges from cross section measurements, e.g. (n, f), (n, p), (n, α) as well as (p, p′), (p, n) and (p, γ), nuclear fission research, material studies (e.g. radiation-induced damage), to the investigation of advanced methods in nuclear technologies, safety and security. The MONNET neutron source offers beamtime to external user within the JRC EUFRAT Open Access program. Proposal evaluation by an independent panel is taking place up to two times per year.

Design of Radiation Resistant Pre-amplifier for fusion reactors

The research of controlled nuclear fusion is not a simple process. The upcoming accomplishment of ITER means the beginning of a new phase of controlled nuclear fusion, which is building a fusion reactor. The operating electronics related to fusion reactors need to adapt to harsh environment and minimize the risk of any possible irradiation. Pre-amplifiers are widely used for signal conditioning in various diagnostic systems. And if not shielded, they would be easily damaged in a environment with strong radiation. In this study, a kind of Radiation Resistant Pre-amplifier (RRP) has been designed and manufactured. To verify its performance under radiation, tests in both gamma and neutron fields were carried out. And the performance of RRP is compared with that of an Ordinary Pre-amplifier (OP). The RRP was irradiated with gammas from a Co-60 source up to an accumulated dose of 1MGy, and was also irradiated with neutrons under a tandem accelerator up to a total neutron flux of 1013 n/cm2. The test results prove a performance improvement of radiation hardness on the RRP. And shielding optimization has been discussed with the circumstances of ITER port cell area in this paper. The RRP could better adapt to the complex irradiation environment of fusion reactors and possibly reduce shielding in the future.

Investigation of γ softness: Lifetime measurements in Ru104,106

Lifetimes of the ${2}_{1}^{+}, {4}_{1}^{+}, {6}_{1}^{+}, {2}_{\ensuremath{\gamma}}^{+}$, and ${3}_{\ensuremath{\gamma}}^{+}$ states in $^{104,106}\mathrm{Ru}$ were measured by using the recoil-distance Doppler-shift technique and the Cologne Plunger device. Low-lying excited states in both nuclei were populated in a $^{104}\mathrm{Ru}(^{18}\mathrm{O},^{18}\mathrm{O})^{104}\mathrm{Ru}$* inelastic scattering and in a $^{104}\mathrm{Ru}(^{18}\mathrm{O},^{16}\mathrm{O})^{106}\mathrm{Ru}$ two-neutron transfer reaction using the Cologne FN Tandem accelerator. The experimental energy levels and deduced electromagnetic transition probabilities are compared in the context of $\ensuremath{\gamma}$ softness and the mapped interacting boson model with input from the microscopic self-consistent mean-field calculation using a Gogny interaction. The newly obtained results for the $\ensuremath{\gamma}$ band give a more detailed insight about the triaxial behavior of $^{104,106}\mathrm{Ru}$. The results will be discussed in the context of $\ensuremath{\gamma}$ soft and rigid triaxial behavior which is present in the neutron-rich Ru isotopes.

Atomic-scale study of He ion irradiation-induced clustering in α-Zirconium

Zircaloy-4 alloy specimens consisting of α-Zr grains were irradiated on a tandem accelerator with 5 MeV He ions to a fluence of 5 × 1021 ions m − 2 at different temperatures. Defect clusters and He bubbles were observed in the TEM micrographs of the irradiated microstructure. The small defect clusters and He bubbles were found to exhibit spherical shapes whereas the large defect clusters showed plate-like shapes. Molecular dynamics simulations and crystallography analyses revealed that the defect clusters are mainly composed of Zr interstitials. During He-ion irradiation, the clustering of Zr dumbbell interstitials results in the formation of small and spherical defect clusters. With further irradiation, the Zr interstitials prefer to occupy the octahedral sites that align along the {12¯14} planes with other site interstitials, forming cluster sections. These initial planar clusters then grow by extending along the <101¯0> directions and by forming more cluster sections along the <12¯16> directions, leading to large plate-like defect clusters on the {1¯21¯1}planes. He bubbles nucleate by the clustering of He atoms and vacancies that are formed by kicking out the lattice atoms, and then grow by the migration and coalescence of helium-vacancy clusters. Small He atoms have many interstitial sites to occupy in the α-Zr HCP crystal, allowing He bubbles to grow to spherical shapes. In addition, grain boundaries induce the accumulation of primary point defects and He atoms and high irradiation temperature accelerates diffusion, and hence larger defect clusters and He bubbles form in the grain boundary regions and at higher irradiation temperature.

New K isomers in Cf248

The nuclear structure of $^{248}\mathrm{Cf}$ was investigated at the Tokai Tandem Accelerator Laboratory of the Japan Atomic Energy Agency. $^{248}\mathrm{Cf}$ was one of the nuclei produced in the $^{18}\mathrm{O}+^{249}\mathrm{Cf}$ multinucleon transfer reaction. An array of Ge and ${\mathrm{LaBr}}_{3}$ detectors was used to detect the $\ensuremath{\gamma}$ rays emitted. More than ten new $\ensuremath{\gamma}$-ray transitions from $^{248}\mathrm{Cf}$ were observed and, for the first time, lifetimes of excited states in the nanosecond range were measured. For the previously known bandhead of the ${2}^{\ensuremath{-}}$ octupole vibrational band at 592 keV, a lifetime of 6.7(2) ns was found. Another, new isomeric state, with a lifetime of 16.8(5) ns, decays via a 48-keV $E1$ transition to a much longer-lived state lying at 0.9(3) MeV, for which a lifetime larger than $\ensuremath{\approx}200$ ns is estimated. For this latter state, the unobserved decay points to $K\ensuremath{\geqslant}5$. Considering available theoretical models, possible spin-parity assignments of new states are discussed.

Status of the X17 search in Montreal

At the Montreal Tandem accelerator, an experiment is being set up to measure internal pair creation from the decay of nuclear excited states using a multiwire proportional chamber and scintillator bars surrounding it from the Daphne experiment. The acceptance covers a solid angle of nearly 4π. Preamplifiers and the data acquisition hardware have been designed and tested. The 7LiF target, mounted on an Al foil and water-cooled is in a thin carbon fiber section of the beamline. The experiment will focus at first on a measurement of the internal pair creation from the 18.15 MeV state of 8Be with the aim of observing independently the X17 particle discovered by the ATOMKI experiment. Assuming the ATOMKI evaluation of the electron-pair production rate from X17, Geant4 simulation predicts observation of a clear signal after about 2 weeks of data taking with 2 μA proton beam. The IPC measurement could eventually be extended to the giant dipole resonance of 8Be, as well as to other nuclei, in particular to 10B.

Cross sections of the Ca40(n,α0)37Ar and Ca40(n,α)37Ar reactions in the 8.50–9.50 MeV neutron energy range

Cross sections of the $^{40}\mathrm{Ca}(n,\phantom{\rule{0.16em}{0ex}}{\ensuremath{\alpha}}_{0})^{37}\mathrm{Ar}$ and $^{40}\mathrm{Ca}(n,\phantom{\rule{0.16em}{0ex}}\ensuremath{\alpha})^{37}\mathrm{Ar}$ reactions at five neutron energy points in the $8.50--9.50$ MeV energy region were measured. The monoenergetic neutrons were produced through the $^{2}\mathrm{H}{(d,\phantom{\rule{0.16em}{0ex}}n)}^{3}\mathrm{He}$ reaction based on the HI-13 tandem accelerator of China Institute of Atomic Energy (CIAE). A twin gridded ionization chamber (GIC) was used as the charged particle detector. Detailed simulations were performed to determine the nuclear reaction events and detection efficiencies. Present results are compared with existing measurement and evaluation data, which shows that the evaluation data from all libraries are higher than the measurement data in the $8.50--9.50$ MeV region for the $^{40}\mathrm{Ca}(n,\phantom{\rule{0.16em}{0ex}}\ensuremath{\alpha})^{37}\mathrm{Ar}$ reaction. TALYS-1.9 code was used for theoretical calculations. Calculation results using the TALYS-1.9 code with the adjusted parameters are in agreement with the present measurements, which also show that the compound mechanism predominates the $^{40}\mathrm{Ca}(n,\phantom{\rule{0.16em}{0ex}}\ensuremath{\alpha})^{37}\mathrm{Ar}$ reaction in the $8.50--9.50$ MeV region. Both present measured forward/backward ratios and TALYS-1.9 calculations suggest that the direct and preequilibrium mechanisms are non-negligible for the $^{40}\mathrm{Ca}(n,\phantom{\rule{0.16em}{0ex}}\ensuremath{\alpha})^{37}\mathrm{Ar}$ reaction in the $8.50--9.50$ MeV region.

Accelerator mass spectrometry with ANU’s 14 million volt accelerator

Accelerator Mass Spectrometry (AMS) at the Department of Nuclear Physics and Accelerator Applications (Australian National University) is based on a 14UD tandem accelerator. The 14UD has demonstrated exceptional accelerator performance over more than three decades of AMS, e.g. by running regularly above 14 MV. We present the actual performance for the whole range of measured radionuclides and the potential of this specialised high-energy AMS facility - demonstrating the continuing need for such a system. Focus here will be also on the unique setup comprising an Enge split-pole spectrograph used as a gas-filled magnet (GFM). The GFM has seen growing importance at ANU over the years as a means for providing an efficient reduction of isobaric background. We use the Enge now routinely for 10Be, 26Al, 32Si, 53Mn and 60Fe measurements.

The new 300 kV multi-element AMS system at the TONO Geoscience Center, Japan Atomic Energy Agency

A new AMS system (HVEE 4103Bo-AMS) was installed at Tono Geoscience Center, Japan Atomic Energy Agency in November 2019 and AMS experiments started in 2020. The system consists of a SO-110C Cs sputtering ion source, a low-energy spectrometer with an ESA and an injection magnet, a 300 kV tandem accelerator, a high energy spectrometer with two analyzing magnets and an ESA, and a gas ionization chamber for rare isotope measurement. The system is designed for high-sensitivity detection of 10Be, 14C, 26Al and 129I. A comparison with our 5 MV Pelletron is also given in this paper.

Isobar separation of 32Si from 32S in AMS using a passive absorber

An accelerator mass spectrometry (AMS) method has been developed to detect 32Si and separate it from its intense isobar 32S. This separation is achieved using a passive absorber cell in front of a gas ionization chamber at an energy of 30 MeV at the 6 MV Tandem accelerator at the Laboratory of Ion Beam Physics (LIP) at the ETH Zurich. Thereby, the background originating from light recoils was identified and minimized. Additionally, the deviation of the position of the observed spectrum from the expected was explained. The new method is currently undergoing characterisations aiming for the half-life measurement of 32Si.

Rotational sequences in N=98 Tm167 populated in the Dy164(Li7,4nγ)Tm167 fusion-evaporation reaction

High spin states in $_{69}^{167}\mathrm{Tm}_{98}$ were studied using the $^{164}\mathrm{Dy}(^{7}\mathrm{Li},4n\ensuremath{\gamma})^{167}\mathrm{Tm}$ fusion-evaporation reaction. The XTU Tandem accelerator at the INFN Legnaro National Laboratory was used to accelerate a beam of $^{7}\mathrm{Li}$ ions to 55 MeV, and $\ensuremath{\gamma}$ rays from the evaporation residues were studied using the GASP Ge multidetector $\ensuremath{\gamma}$-ray array. The present data have allowed the $1/{2}^{\ensuremath{-}}[541]$ yrast sequence of $^{167}\mathrm{Tm}$ to be established to spin $61/{2}^{\ensuremath{-}}$, the $1/{2}^{+}[411]$ ground-state band to be extended to $(51/{2}^{+})$, and the $7/{2}^{+}[404]$ and $7/{2}^{\ensuremath{-}}[523]$ rotational sequences to be extended to spins $(43/{2}^{+})$ and $(39/{2}^{\ensuremath{-}})$, respectively. The experimental data have been compared with the results of cranked shell-model calculations; for the above decay sequences, crossing frequencies are in agreement with those of the neighboring even-even isotones, within experimental errors, and there is no evidence of a configuration-dependence of band crossing frequencies. Experimental $B(M1)/B(E2)$ values were extracted and compared with the results of theoretical calculations which are based on a semiclassical cranking model. Finally, the experimental high-spin decay sequences have been compared with the results of projected shell-model (PSM) calculations; agreement between experiment and theory is excellent over the complete range of spins. The calculated energy levels of the one-quasiparticle bands in $^{167}\mathrm{Tm}$ depend sensitively on the deformation parameters used in the PSM calculation.

Mathematical Modeling and Optimization of Low Energy Beam Line in 2MV Pelletron Accelerator

The 2 MV 6SDH-2 tandem pelletron accelerator installed at CASP, GC University Lahore has evolved over the past years from acceptance tests to an extremely reliable and convenient research tool in the field of particle accelerator physics, hav-ing capability of providing variety of ion beams from few keV to several MeV in energy. Many electrostatic and magnetic devices are employed to steer an ion beam in an accelerator system all the way from ion source to experimental setup. Mathematical modeling and optimization of low energy beamline has been done for this accelerator. Several ion optics and steering devices are provided in the pre-acceleration beamline for ion beam manipulation and in order to optimize the overall beam transmission. As the quality of the beam from the accelerator depends upon the design of these electrostatic and magnetic devices, optimum settings are derived by manually adjusting voltages and currents provided to low energy beam-line components. From these calibrations and optimization measurements, calculations has been done for mass analysis magnets, steering and focusing components and the results has been represented. From the results, it has been found that there exists a complex relationship between the effects of different voltages and currents in order to tune the desired output current and beam profile at the end-stations. Details of experiments and data analysis are presented.

Development of a Clinical Neutron Source for Boron Neutron Capture Therapy

<h3>Purpose/Objective(s)</h3> In boron neutron capture therapy (BNCT), a source of epithermal (1 eV to 30 keV) neutrons activates high concentrations of ¹⁰B, selectively accumulated in tumor cells from infusion of a non-radioactive pharmaceutical, whose high LET reaction products fully deposit their energy within 10 microns of the reaction site. Historically, only nuclear reactors provided sufficient neutron intensity and beam quality for clinically acceptable BNCT treatments, but hospital-based BNCT is now feasible using compact accelerator sources. The present work has designed a system to produce an epithermal neutron beam using a tandem electrostatic accelerator, proton beam line, neutron-producing targets, neutron beam shaping assembly (BSA) and collimators. Testing was required to verify that this design can produce a clinically viable neutron source for BNCT in terms of total neutron yield, output reproducibility and operational stability. <h3>Materials/Methods</h3> The present neutron source uses neutrons from the ⁷Li(p,n)⁷Be reaction at nominal proton energy and current of 2.5 MeV and 10 mA. A negative hydrogen ion source is pre-accelerated to 200 keV and injected into the tandem accelerator, which increases the negative ion kinetic energy to half the goal proton energy at its center. A charge exchange target strips the electrons to create positively-charged protons that are further accelerated to the full operational energy at the tandem exit. The proton beam is focused and may be directed to up to three treatment rooms, each with a copper-backed target of natural lithium metal under vacuum. The maximum neutron energy from 2.5 MeV protons slowing down in lithium is 800 keV and requires moderation to the desired epithermal range. A static beam BSA surrounds the target and provides efficient neutron moderation and reflection using carefully chosen materials. The BSA's 25 cm circular exit port may be collimated to small circular epithermal beam diameters as small as 5-8 cm. <h3>Results</h3> A tandem accelerator, proton beam line and lithium target have been installed and began initial testing. Proton energy and current up to 2.3 MeV and 7 mA have been achieved for continuous operating periods exceeding 30 minutes with no energy or current degradation. Raster patterns have been designed to scan the 1-cm diameter proton beam over a 10-cm circular area on the lithium target, and water cooling of the copper backing has maintained maximum target temperatures below 150°C. The measured lithium deposition uniformity is expected to translate to a neutron yield uniformity better than 5%. <h3>Conclusion</h3> This BNCT neutron source has demonstrated operational stability and reproducibility of proton energy, proton current and neutron production. These measurements support an expectation that the equipment currently undergoing evaluation, in combination with the planned BSA, will meet the necessary requirements for a hospital-based, clinical BNCT system.

Study of the 176Hf(n,2n)175Hf cross section at 18.9 MeV

Neutron nuclear reactions can provide significant information in the field of nuclear physics and applications. Hafnium (Hf) is one of the rare-earth isotopes with a relative large neutron total cross-section in the thermal neutron energy region and neutron induced reactions in reactor materials could lead to the production of long-lived isomeric states of Hf isotopes. Thus, the knowledge of neutron cross-sections on Hf isotopes is of great importance for basic research in Nuclear Physics as well as for applications concerning the interaction of neutrons with matter. In this study measurements of experimental cross section for the 176Hf(n,2n)175Hf and 180Hf(n,n΄γ)180mHf reactions were carried out, using the activation technique. The neutron beam energy at 18.9 MeV was produced via the 3H(d,n)4He reaction at the 5.5 MeV Tandem Van de Graaf accelerator laboratory of NCSR “Demokritos”. A thin metallic foil of natural Hf was used, while for the determination of the neutron flux at the target position a reference foil of Al was placed at the back of the Hf target. The irradiation was continuous for 28 hours leading to a total neutron fluence of 1010 n/cm2 and a BF3 detector was used for monitoring the neutron flux during the irradiation. After the end of irradiation, the activity of the Hf target and the Al foil were measured off-line by two HPGe detectors. Both detector efficiencies were obtained using a calibrated 152Eu source, placed in the same distance as the target and the reference foil. The 176Hf(n,2n)175Hf reaction has been corrected from the contribution of 177Hf(n,3n)175Hf and the 174Hf(n,γ)175Hf reactions and the 180Hf(n,n΄γ)180mHf reaction from the 179Hf(n,γ)180mHf. Theoretical calculations of the 174Hf(n,2n)175Hf, 176Hf(n,2n)175Hf and 180Hf(n,n΄γ)180mHf reaction cross-sections have also been performed using the nuclear statistical code “EMPIRE 3.2.3” and they have been compared with the data.

Study of the Elastic Scattering in the d + 11B system for EBS purposes

The implementation of boron in several fields, such as in the creation of p-type semiconductors in electronics, has created the need for the accurate quantitative determination of its depth profile concentrations in near surface layers of various matrices. In the framework of IBA techniques a combination of Elastic Backscattering Spectroscopy, along with Nuclear Reaction Analysis, has been proposed in order to address the current needs for boron depth profiling, focusing on the use of proton beams. Deuteron beams however offer superior mass resolution with similar stopping power values and simultaneous excitation of most light elements. Unfortunately, the lack of experimental datasets concerning the deuteron elastic scattering on boron impedes their use. Thus, in the present work, the first set of measurements for the 11B(d,d0) differential cross section covering the Ed,lab=1300-1860 keV energy range for the backscattering angles of 150ο, 160ο and 170ο were carried out. The study was conducted at the 5.5 MV Tandem Accelerator of the Institute of Nuclear and Particle Physics, in the National Center of Scientific Research “Demokritos”, Athens, Greece. The target was a thin, self-supporting aluminum foil, upon which a thin natB (isotopic ratio: 11B 80.1%, 10B 19.9%) layer was deposited using the sputtering technique at RBI, Zagreb, Croatia, followed by the evaporation of an ultra-thin layer of 197Au on top for normalization and wear protection purposes. The outgoing particles were detected using silicon surface barrier (S.S.B.) detectors and the differential cross sections for elastic scattering were determined from the resulting spectra via the relative technique