Carmen Angulo

• PhD Physics
• SCK-CEN - Belgian Nuclear Research Centre

The total cross section of the nuclear reaction 89Y(p,7)90Zr has been measured over the proton energy range EP=1.6-2.4 MeV. The results are compared with the predictions of statistical model calculations

The MYRRHA project aims at coupling a cw 600 MeV, 4 mA proton linac with a sub-critical reactor as the very first prototype nuclear reactor to be driven by a particle accelerator (ADS). Among several applications, MYRRHA main objective is to demonstrate the principle of partitioning and transmutation (P&T) as a viable solution to drastically reduce...

The space and time configurations of the dissociation of ⁸He into ⁶He+n+n, on C and Pb targets, have been explored simultaneously for the first time. The final-state interactions in the n-n and ⁶He-n channels are successfully described within a model that considers independent emission of neutrons from a Gaussian volume with a given lifetime. The d...

The MYRRHA project aims at coupling a cw 600 MeV, 4 mA proton linac with a sub-critical reactor as the very first prototype nuclear reactor to be driven by a particle accelerator (ADS). Among several applications, MYRRHA main objective is to demonstrate the principle of partitioning and transmutation (P&T) as a viable solution to drastically reduce...

A collaboration of SCK•CEN, IAP and BEVATECH GmbH is currently constructing the room temperature CH section of the 16.6 MeV CW proton injector for the MYRRHA project. The elaboration of all the construction readiness files for the construction of the accelerating cavities of the first CH section (1.5 to 5.9 MeV) is ongoing. In parallel, the plannin...

The unbound nucleus He7 has been investigated via the reaction of a 16.8 MeV He6 radioactive ion beam on a Be9 target. The measurement of the outgoing Be8 through its well characterized two-α decay permitted the energy of the He6+n system to be reconstructed. Through comparison with a complete Monte Carlo simulation incorporating R-matrix lineshape...

While siphon breakers are well known and widely used, the relationship between the undershooting height (defined as the height difference between the siphon breaking device and the final water volume level) and the system design is poorly understood. The system code RELAP5 simulation tool has been tested to assess its ability to correctly predict t...

Active cooling systems are vulnerable to component failures or loss of electrical power. Consequently, to increase the reliability of the system as a whole, adequate redundancy for these components as well as electrical back-up power sources must be provided. The Fukushima Daiichi accident however demonstrates that, despite redundancy and alternati...

The elastic scattering and inclusive α-particle yield for the 6He+206Pb system at an incident energy of 18 MeV, just below the nominal Coulomb barrier, have been measured. The α-particle yield at forward angles is also reported. The data are analyzed by means of continuum-discretized coupled-channels, distorted wave Born approximation, and coupled...

In order to reduce the volume and the radiotoxicity of the nuclear waste coming from the operation of existing pressurized water reactors, accelerator-driven systems (ADSs) have been envisioned. The Lead-Cooled (Pb) European Facility for Industrial-Scale Transmutation (EFIT) (Pb-EFIT) plant is the first ADS design that has been going into a rather...

The FP6 RAPHAEL Integrated Project on V/HTR technology concluded in April 2010 after 5 years of successful performance. 35 partners from 10 Member States, an overall budget above 18 MEUR and about 170 key deliverables are some important figures of the project.RAPHAEL provides results in seven V/HTR technology areas: core physics, fuel, fuel cycle b...

Developers of High Temperature Reactors (HTR) worldwide acknowledge that the main asset for market breakthrough is its unique ability to address growing needs for industrial cogeneration of heat and power (CHP) owing to its high operating temperature and flexibility, adapted power level, modularity and robust safety features. A strong alliance betw...

Measurements of the 4He(7Be,α)7Be and 4He(7Be,p)10B reactions were performed using 7Be beam energies of 7.1 and 23 MeV and a helium-4 target, employing the thick target technique. Resonances were observed between Ex(11C)=8.6 to 13.8 MeV. An R-matrix analysis was performed to characterize the spins and partial widths. This analysis showed that the o...

Measurements of the 4He(7Be,α)7Be and 4He(7Be,p)10B reactions were performed using 7Be beam energies of 7.1 and 23 MeV and a helium-4 target, employing the thick target technique. Resonances were observed between Ex(11C)=8.6 to 13.8 MeV. An R-matrix analysis was performed to characterize the spins and partial widths. This analysis showed that the o...

The most intense gamma-ray line observable from novae is likely to be from positron annihilation associated with the decay of 18F. The uncertainty in the destruction rate of this nucleus through the 18F(p,{\alpha})15O reaction presents a limit to interpretation of any future observed gamma-ray flux. Direct measurements of the cross section of both...

Fusion and transfer + breakup channels have been studied in the collision induced by the two-neutron-halo 6He on a 64Zn target at energies from below to above the Coulomb barrier. For comparison, the reaction induced by the stable isotope 4He on the same target has been studied. The fusion cross section has been measured by using an activation tech...

In this work we present new data for the sub‐barrier fusion of the system 6He+206Pb obtained in the Centre de Recherches du Cyclotron (UCL), in Louvain‐la‐Neuve, Belgium. The preliminary results suggest the absence of fusion enhancement at sub‐barrier energies.

Experimental results of the elastic scattering of 6He on 208Pb at ELAB=22 MeV, measured at the CRC facility (Louvain-la-Neuve, Belgium), are presented, including results on the 4He production channel. These data were taken with full angular coverage and high angular resolution. Both experimental cross sections are compared with continuum discretize...

7 pages, 4 figures, 2 tables, expérience GANIL/SPIRAL

Cross-sections for the production of 210Po nuclei in 6He + 206Pb collisions over the incident energy range 14-18MeV were measured by means of the activation technique and a radiochemical analysis. The elastic scattering at 18.0MeV was also measured providing a precise value for the 210Po production cross-section at this energy. The results are at v...

During the past ten years the present collaboration has carried out several experiments related with the study of radioactive nuclei. One of the topics in which we have centered our research, is the scattering of halo nuclei at energies around the Coulomb barrier. As part of this study, we present in this work a review of the results obtained from...

During the past ten years the present collaboration has carried out several experiments related with the study of radioactive nuclei. One of the topics in which we have centered our research, is the scattering of halo nuclei at energies around the Coulomb barrier. As part of this study, we present in this work a review of the results obtained from...

It is already 10 years since the (European) HTR Technology Network (HTR-TN) launched a programme for the development of HTR Technology, which expanded through 3 successive Euratom Framework Programmes, with many coordinated projects in line with the strategy of the Network. Widely relying in the beginning on the legacy of the former European HTR de...

This document is a General Synthesis Report of the Different ADS Design Status being designed within the EUROTRANS Integrated Project; an FP6 European commission partially funded programme. This project had the goal to demonstrate the possibility of nuclear waste transmutation/burning in Accelerator Driven Systems (ADS) at industrial scale.The focu...

Within the integrated project EUROTRANS, design and safety analysis of the accelerator driven systems XT-ADS and EFIT have been made. XT-ADS is based on MOX fuel and LBE coolant, has a design power of 57 MWth and is mainly intended as an irradiation facility. It is also expected to prove the feasibility of coupling a high power proton accelerator w...

No abstract prepared.

Reactions of a 16.8 MeV 6He beam with a 9Be target have been investigated using highly segmented detector setup covering a large solid angle. Data on elastic and quasi-free scattering, as well as two-neutron transfer, are reported. The results for elastic scattering are fairly well reproduced by a CDCC calculation, in agreement with the interpretat...

We present new data for the reaction 7Be+9Be measured at Elab = 23.7 MeV. The elastic scattering angular distribution has been analyzed using the phenomenological optical model and the coupled‐channels method. In the latter approach, we assumed a two‐cluster model of the 7Be nucleus, and we included explicitly the ground state and first excited sta...

The largest nuclear physics uncertainty in studies of gamma-ray emission from novae arises from the 18F(p,α)15O reaction rate that affects the abundance of 18F. Direct measurements have been made of the 18F(p,p)18F and 18F(p,α)15O reaction differential cross sections in the energy range 0.6⩽Ec.m.⩽1.6 MeV. Several resonances have been observed in bo...

Six proton-emitting states in 19Ne were studied through the inelastic scattering reaction H(19Ne,p);{19}Ne; (p)18F. Their energies and widths were derived from the protons detected at zero degree, while proton-proton angular correlations between the detector at zero degree and a segmented annular detector were used to determine their spin value. In...

During nova outbursts the decay of 18F is the main source of γ-ray emission at and below 511 keV. In spite of much experimental effort, the quantity of 18F synthesized still suffers from large uncertainties which arise mainly from the 18F(p, α)15O reaction cross section at low energies. We report here on a new direct measurement carried out at the...

The experiment was performed at the Centre de Recherches du Cyclotron at Louvain-la-Neuve (Belgium) using a 19Ne6+ radioactive beam.

During nova outbursts the decay of 18F is the main source of γ -ray emission at and below 511 keV. In spite of much experimental effort, the quantity of 18F synthesized still suffers from large uncertainties which arise mainly from the 18F(p, α)15O reaction cross section at low energies.We report here on a new direct measurement carried out at the...

We improve standard big bang nucleosynthesis (SBBN) calculations by taking into account new nuclear physics analyses (the 2003 work of Descouvemont and coworkers). Using a Monte Carlo technique, we calculate the abundances of light nuclei (D, 3He, 4He, and 7Li) versus the baryon-to-photon ratio. The results concerning Ωbh2 are compared with relevan...

The WMAP satellite, devoted to observations of the anisotropies of the cosmic microwave background radiation, has recently provided a determination of the baryonic density of the universe with unprecedented precision. Using this, big bang nucleosynthesis calculations predict a primordial 7Li abundance that is a factor of 2-3 higher than that observ...

This chapter concentrates on experimental techniques currently used to investigate nuclear reactions of astrophysical interest. After a brief introduction, I shall present the basic quantities and equations governing thermonuclear reaction rates in stellar plasma. The various astrophysical scenarios, from hydrostatic to advanced burning stages up t...

Due to its high operating temperature (up to 850°C with present technologies, possibly higher in the longer term), and its power range (a few hundred MW), the modular HTR could address a larger scope of industrial process heat needs than other present nuclear systems. Even if HTR can contribute to competitive electricity generation, this potential...

Experiments on halo nuclei at energies around the Coulomb barrier can provide good quality data on elastic, inelastic, breakup and nucleon transfer reactions. This information turns out to be very important to understand the structure and dynamics of these exotic nuclei. In this work we present relevant results obtained from recent scattering exper...

The elastic scattering of 6He on 208Pb has been measured at laboratory energies of 14, 16, 18 and 22 MeV. These data were analyzed using phenomenological Woods–Saxon form factors and optical model calculations. A semiclassical polarization potential was used to study the effect of the Coulomb dipole polarizability. Evidence for long range absorptio...

The O16(p,gamma)F17 reaction rate is revisited with special emphasis on the stellar temperature range of T=60-100 MK, important for hot bottom burning in asymptotic giant branch (AGB) stars. We evaluate existing cross-section data that were obtained since 1958 and, if appropriate, correct published data for systematic errors that were not noticed p...

Fusion and direct processes have been studied for the 6He + 64Zn reaction at energies around the Coulomb barrier, in order to investigate the effects of the projectile halo structure on the reaction mechanisms. As comparison, the 4He + 64Zn reaction was also studied. No effect has been observed on the fusion cross section for the 6He when compared...

We present an experimental study of 19Na states in the excitation energy range between 2 and 3 MeV. The presence of 19Na single-particle levels at these energies was first predicted by a microscopic cluster model and then experimentally confirmed by measuring the elastic and inelastic scattering of a 66 MeV 18Ne radioactive beam on a (CH2)n target....

Experiments on halo nuclei at energies around the Coulomb barrier can provide good quality data on elastic, inelastic, breakup and nucleon transfer reactions. This information turns out to be very important to understand the structure and dynamics of these exotic nuclei. In this work we present relevant results obtained from recent scattering exper...

The low‐energy levels of 19 Na were studied in the center‐of‐mass energy ( E CM ) range from 2.6 to 3.4 MeV, by using the elastic and inelastic scattering methods in inverse kinematics. The 18 Ne + p scattering reactions, leading to the ground state and the first excited state of 18 Ne , were investigated by using a 66 MeV radioac...

The 18F, produced during nova explosions, is the main responsible for the 511 keV γ-ray emitted during the outburst that could be detected with satellite missions or future γ-ray telescopes. In spite of many experimental efforts, the amount of 18F synthesized still suffers from large uncertainties concerning mainly the 18F(p,α)15O reaction. We rep...

The 6He+12,14C scattering and reactions have been studied using a 35 MeV 6He radioactive beam and preliminary results are presented. The three-body reaction 6He+ 12C → 10Be+2 α has been clearly identified and sequential decay of intermediate states in 14C has been studied. Search for an analog reaction on 14C, 6He+14C → 12Be+2 α, has not given conc...

20 pages, 5 figures.-- PACS nrs.: 24.10.Eq, 24.50.+g, 25.70.Mn, 25.70.Hi.-- Second version of the pre-print: Submitted on 11 May 2007 (v1), last revised 29 Nov 2007 (this version, v2).-- Published in: Nuclear Physics A792: 2-17 (2007). New experimental data from the scattering of 6He+208Pb at energies around and below the Coulomb barrier are presen...

The early E⩽511 keV gamma-ray emission from novae depends critically on the reaction. Unfortunately the reaction rate of the reaction is still largely uncertain due to the unknown strengths of low-lying proton resonances near the threshold which play an important role in the nova temperature regime. We report here our last results concerning the st...

The elastic-scattering, neutron transfer and projectile break-up channels have been studied for the reaction 6He + 64Zn at energies around the Coulomb barrier. The results show a very large break-up and transfer cross-section corresponding to the largest fraction of the total reaction cross-section. No evidence of threshold anomaly emerged from the...

to be published in AIP Conference Proceedings

We present new cross section data for the complete fusion of the weakly bound systems $^{7,9}\mathrm{Be}$ and $^{7}\mathrm{Li}$ on $^{238}\mathrm{U}$ at energies around the Coulomb barrier. In the same measurement, yields for direct processes and incomplete fusion are detected. For all systems, a suppression of the complete fusion cross section aro...

Explosive stellar environments such as novae and X-ray bursts are currently among the most exciting topics in nuclear astrophysics. Reactions on unstable nuclei play a crucial role in energy generation and nucleosynthesis due to the high temperatures and short reaction time scales in these events, but substantial uncertainties exist in nuclear reac...

The study of reaction mechanisms in collisions induced by halo and/or weakly bound nuclei around the barrier has recently been the subject of many theoretical and experimental papers. Here we discuss our recent results concerning the study of the systems 13N+9Be and 6He+64Zn.

The present paper concerns the study of reactions induced by radioactive beams of halo and weakly bound nuclei at energies around and above the Coulomb barrier. The results obtained for the reaction induced by the halo nucleus He-6 on Zn-64 have been Compared with the results for the reaction induced by He-4 on the same target. The results of the r...

Nuclear reactions are responsible for the nucleosynthesis and energy generation in stars. From all the stellar sites, explosive events have attracted great attention in the last years. Due to the high temperatures and short reaction time scales in these events, nuclear reactions on unstable nuclei play a crucial role. However, substantial uncertain...

Low‐lying states of 19 Na were investigated using both elastic and inelastic scattering of a 18Ne beam on a (CH2)n target. The experimental method is briefly described. Preliminary results are presented.

We have investigated the low‐energy states of 11N by the elastic scattering method in inverse kinematics using a 10C beam and a (CD2) n target. Recoil protons were detected at 16 laboratory angles θlab = 4.6° – 18.9° in a ΔE − E detector system. Using the R‐matrix method to analyse the 10C + p elastic cross sections, we found 11N to be unbound wit...

Using the very precise value of the baryonic density of the Universe recently obtained by WMAP, Big Bang Nucleosynthesis calculations predict a primordial 7Li abundance which is a factor 2 – 3 higher than that observed in galactic halo dwarf stars. Up to now, the role of the 7Be(d,p)2α reaction has been neglected. We have studied this reaction, for...

The astrophysical reaction rates of the 16O(a,g)20Ne capture reaction and its inverse 20Ne(g,a)16O photodisintegration reaction are given by the sum of several narrow resonances and a small direct capture contribution at low temperatures. Although the thermal population of low lying excited states in 16O and 20Ne is extremely small, the first excit...

The 10.15 MeV resonance in 10Be has been probed via resonant 6He+4He elastic scattering. It is demonstrated that it is the Jpi=4+ member of a rotational band built on the 6.18 MeV 0+ state. A Gammaalpha of 0.10-0.13 MeV and Gammaalpha/Gamma=0.35-0.46 were deduced. The corresponding reduced alpha width, gamma2alpha, indicates one of the largest alph...

The 10.15 MeV resonance in {sup 10}Be has been probed via resonant {sup 6}He+{sup 4}He elastic scattering. It is demonstrated that it is the J{sup {pi}}=4{sup +} member of a rotational band built on the 6.18 MeV 0{sup +} state. A {gamma}{sub {alpha}} of 0.10-0.13 MeV and {gamma}{sub {alpha}}/{gamma}=0.35-0.46 were deduced. The corresponding reduced...

. The 15O(α,α)15O elastic scattering is investigated using a 15O radioactive beam and a He gas cell limited by Mylar windows. The width of a 19Ne state at an excitation energy of 5.35MeV is measured as Γα = 3.2±1.6keV, in agreement with charge symmetry estimate.

We have investigated the low-energy states of 11N by the resonant elastic-scattering method in inverse kinematics using a 10C beam and a (CH2)n target at the CYCLONE facility at Louvain-la-Neuve. Recoil protons were detected at laboratory angles θlab=5.2°-18.3° in a ΔE-E detector system. The absolute 10C+p elastic cross-section data were analyzed i...

We have investigated the low-energy states of 11N by the resonant elastic-scattering method in inverse kinematics using a 10C beam and a (CH2)n target at the CYCLONE facility at Louvain-la-Neuve. Recoil protons were detected at laboratory angles thetalab=5.2°-18.3° in a DeltaE-E detector system. The absolute 10C+p elastic cross-section data were an...

Nuclear astrophysics has revealed as one of the most exciting areas of interdisciplinary research, in the crossroads of nuclear physics, astrophysics and astronomy. As a driving force for the development of the very first Radioactive Ion Beam (RIB) Facilities, it remains a fundamental research area in many European laboratories and is one of the ke...

The reaction rate of 18F(α,p)21Ne has been studied in the inverse kinematics using a radioactive 18F beam and in the time-reverse reaction 21Ne(p,α)18F using the off-line counting activation method. They have been measured in the energy range of the relevant Gamow window. Experimental results will be discussed and compared with the results of Hause...

The astrophysical S-factor of 14N(p,gamma)15O has been measured for effective center-of-mass energies between E_eff = 119 and 367 keV at the LUNA facility using TiN solid targets and Ge detectors. The data are in good agreement with previous and recent work at overlapping energies. R-matrix analysis reveals that due to the complex level structure o...

We have measured elastic cross sections of the scattering of 6 He at E-Lab 14, 16, 17, 18 and 22 MeV on Pb-208 in the angular ranges of 20 degrees-64 degrees and 135 degrees-170 degrees. A significant amount of He-4 events is found at energies well below the Coulomb barrier, that becomes dominant above it. Optical model calculations have been perfo...

A new approach to the production and detection of neutron clusters was recently proposed by the DEMON-CHARISSA collaboration. Its application to the breakup of 14Be into 10Be and 4 neutrons revealed 6 events that exhibited the characteristics of a 4n state, either bound or resonant. We have applied this technique to the breakup of another system th...

We present a method for the detection of charged particles, emitted following beta decay, that allows to reduce the background due to beta radiation and thus to facilitate separation of the delayed-particle events. The isotopes of interest are implanted into a highly segmented double-sided silicon strip detector, resulting in excellent precision on...

The aim of the recoil separator ARES, installed at Louvain-la-Neuve, is to study (p,γ) reactions of astrophysical interest involving unstable nuclei. ARES is coupled to CYCLONE44, a cyclotron dedicated to the post-acceleration of intense low-energy radioactive ion beams. The first measurement using a 19Ne radioactive beam has been performed recentl...

The recent WMAP results tightly constrain the baryon density in the universe, which in turn constrains the light element abundance predicted in Standard Big Bang Nucleosynthesis (SBBN). There is a discrepance in the 7Li abundance which cannot be explained by uncertainties in the main reactions included in the SBBN. Up to now, the influence of the r...

We use the R-matrix theory to fit S-factor data on nuclear reactions involved in Big Bang nucleosynthesis. We derive the reaction rates with associated uncertainties, which are evaluated on statistical grounds. We provide S factors and reaction rates in tabular and graphical formats (available at http://pntpm3.ulb.ac.be/bigbang).

14N(p,gamma)15O is the slowest reaction of the CNO cycle and thus it regulates stellar energy production, the flux of CNO neutrinos from the sun, and plays a role in determining the age of the globular clusters. We present R-matrix fits of the capture data to the ground state, the 6.79 MeV and the 6.18 MeV states in 15O from two recent and independ...

The 14N(p,γ)15O reaction has been investigated by LUNA at the National Laboratory of Gran Sasso (LNGS) using two different techniques. The first study has been performed using a solid target and detecting the γ-rays coming from the single transitions with a HPGe detector in very close geometry to the target. In a second phase a windowless gas targe...

The excitation function for the elastic-scattering reaction p( 18Ne, p) 18Ne was measured with the first radioactive beam from the SPIRAL facility at the GANIL laboratory and with a solid cryogenic hydrogen target. Several broad resonances have been observed, corresponding to new excited states in the unbound nucleus 19Na. In addition, two-proton e...

From the observations of the anisotropies of the Cosmic Microwave Background (CMB) radiation, the WMAP satellite has provided a determination of the baryonic density of the Universe, with an unprecedented precision: 4%. This imposes a careful reanalysis of the standard Big-Bang Nucleosynthesis (SBBN) calculations. In a recent paper, we used the R-m...

The 14N(p,gamma)15O reaction regulates the rate of energy generation in the stellar CN cycle. Because discrepancies have been found in the analysis and interpretation of previous capture data, we have measured the 14N(p,gamma)15O excitation function for energies in the range E(lab)(p)=155-524 keV. Fits of these data using R-matrix theory yield a va...

The 5H system was produced in the 3H(t; p)5H reaction studied at small CM angles with a 58MeV tritium ion beam. High statistics data were used to reconstruct the energy and angular correlations between the 5H decay fragments. A broad structure in the 5H missing-mass spectrum showing up above 2.5MeV was identified as a mixture of the 3/2+ and 5/2+ s...

The nuclear system $^{5}$H was studied using the $^{3}$H($t$,$p$)$^{5}$H transfer reaction at a laboratory energy of 57.7 MeV and small center of mass angles. The energy and angular correlations among the $^{5}$H decay fragments were obtained by complete kinematical reconstruction. A broad structure in the $^{5}$H missing mass spectrum above 2.5 Me...

The WMAP satellite, devoted to the observations of the anisotropies of the Cosmic Microwave Background (CMB) radiation, has recently provided a determination of the baryonic density of the Universe with unprecedented precision. Using this, Big Bang Nucleosynthesis (BBN) calculations predict a primordial $^7$Li abundance which is a factor 2-3 higher...

The 18F nucleus is one of the radioactive isotopes produced during nova explosions. It is of particular interest since it is mainly responsible for the 511 keV gamma-ray emission of novae that could be detected with the INTEGRAL satellite or future gamma-ray telescopes. The amount of 18F synthesised still suffers from large uncertainties coming fro...

The excited states in the 5H system, which was produced in the 3H(t, p)5H reaction with a 58 MeV tritium beam at c.m. angles were investigated. The reconstruction of the energy and angular correlations between the 5H decay fragments was performed by using high statistics data. It was observed that a broad structure in the 5H missing mass spectrum a...