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A sustainable separation concept for large-scale recycling of NdFeB magnets under atmospheric pressure was developed by utilizing a combination of two separation concepts known from the literature: (I) selective pre-separation by in situ chlorination and evaporation of ground oxidized NdFeB material and (II) subsequent distillation for high-purity recovery of all recyclable chlorinated material components, especially its Rare Earth Elements (REEs). Theoretically, simplified estimations of the time conversion curves at 1173 K, 1273 K, and 2000 K of a single particle resulted in the idea of realizing chlorination in some kind of combustion chamber, fluidized bed, or continuous combustion chamber. After chlorination, all non-volatile components, such as REE chlorides, are condensed out of the vapor phase in a single-stage phase separator. For subsequent fine separation by distillation (1292–1982 K for Rare Earth Chlorides and 418–867 K at 2500 kPa for boron and zirconium chloride recovery), simplified simulations were performed in a total-reflux column under ideal phase equilibrium conditions to show the estimated minimum separation effort. Using two composition examples from the literature, high-purity separation of the major Rare Earth Chlorides within a twelve-stage distillation column as a residual heavy boiling product has been demonstrated to be potentially technically feasible.

During the slow neutron capture process in massive stars, reactions on light elements can both produce and absorb neutrons thereby influencing the final heavy element abundances. At low metallicities, the high neutron capture rate of 16-O can inhibit s-process nucleosynthesis unless the neutrons are recycled via the 17O(a,n)20Ne reaction. The efficiency of this neutron recycling is determined by competition between the 17O(a,n)20Ne and 17O(a,g)21Ne reactions. While some experimental data are available on the former reaction, no data exist for the radiative capture channel at the relevant astrophysical energies. The 17O(a,g)21Ne reaction has been studied directly using the DRAGON recoil separator at the TRIUMF Laboratory. The reaction cross section has been determined at energies between 0.6 and 1.6 MeV Ecm, reaching into the Gamow window for core helium burning for the first time. Resonance strengths for resonances at 0.63, 0.721, 0.81 and 1.122 MeV Ecm have been extracted. The experimentally based reaction rate calculated represents a lower limit, but suggests that significant s-process nucleosynthesis occurs in low metallicity massive stars., 7 pages, 5 figures

The present invention relates to a nuclear reactor with a circuit for liquid nuclear fuel which, in contrast to similar systems such as the generation IV liquid salt reactor, does not use the fuel circuit at the same time to remove heat. The cooling is provided instead by a separate cooling circuit in close thermal contact with the conduit of the liquid fuel. In this way, the advantages of a liquid fuel can be fully exploited, while at the same time the cooling circuit can be optimized. This results in considerable simplifications of the safety devices. This reactor also has an optimized neutron economy and is thus able to deactivate its own long-life fission products, such that only short-life radiotoxic waste has to be stored. With the neutron surplus, moreover, long-life radiotoxic constituents from spent fuel in today's light-water reactors can be deactivated or medical radio-isotopes produced.

The target-material dependence of the neutron-proton branching ratio and breaking of the isospin symmetry in the the 2H(d, n)3He and 2H(d, p)3H reactions at very low deuteron energies have been investigated. Angular distributions and total cross sections of the proton and neutron mirror channels have been measured for nuclear reactions taking place in different metallic environments. For Sr , Li , Na targets, we have found a first evidence for an alteration of the neutron-proton branching ratio and angular anisotropy of the neutron channel. We discuss various theoretical approaches explaining isospin mixing effects both in gas and metallic target experiments including a deuteron polarization in the crystal lattice. Direct reaction contribution has been calculated within the zero range distorted wave Born approximation (DWBA).

An in-depth characterization of the TACTIC detector was performed using data from a 148Gd alpha source and some test runs with a stable ion beam. The detector is an active target time-projection chamber with a blind central region for maximizing beam tolerance and GEM-based electron amplification, equipped with a modern digitizing data acquisition system allowing the recording of full signals. The system was developed to study the reaction 8Li(α,n)11B, which is important for bridging the mass 8 gap in scenarios of low 4He density like Inhomogeneous Big Bang Nucleosynthesis and the production of r-process seeds in supernovae. Both energy resolution and tracking accuracy were found to agree with theoretical predictions and Geant4 simulations. The 8Li beam rate capability of the system is predicted to be of the order of 105s-1, several orders of magnitude higher than most previous measurements of the same reaction, while still maintaining a high detection efficiency of 70% to 80 %.

The DRAGON (Detector of Recoils And Gammas Of Nuclear reactions) is used to measure radiative proton and alpha capture reaction rates involving both stable and radioactive, heavy-ion reactants at the TRIUMF-ISAC high intensity radioactive beam facility. Completed in 2001 it has been used for several challenging studies for nuclear astrophysics, e.g. 12 C(α, γ) 16 O, 21 Na(p, γ) 22 Mg, 26g Al(p, γ) 27 Si and 40 Ca(α, γ) 44 Ti. Since initial operation, a number of improvements have been incorporated which are described here. These include a beam centering monitor based on a CCD camera, a mechanical iris to skim of beam halo, a solid state stripper acting as a charge state booster for beams with A ≳ 30, beta and gamma detectors to monitor beam intensity and to determine beam contamination in experiments with radioactive beam and the ionization chamber for both recoil identification and isobar separation.

The Nuclear Astrophysics program at TRIUMF, particular the one centered around the DRAGON and TUDA facilities, as well as some additional experiments will be discussed. In particular, measurements of the 12 C( α , γ ) 16 O, the 26 Al(p, γ ) 27 Si and the 40 Ca( α , γ ) 44 Ti reactions at DRAGON will be described. For the TUDA facility a measurement of 10 B( α ,p) 13 C as a test for the 18 Ne( α ,p) 21 Na measurement is presented. The development of the new cylindrical, large solid angle gas detector TACTIC will be described. In addition, new measurements refuting a temperature dependence of radioactive decay times in metals will be presented as well as GEANT4 simulations regarding the β -delayed α -spectrum of 16 N will be given.

The ground state structure of 9 Li has been investigated through the d( 9 Li ,t) 8 Li one-neutron transfer reaction at E/A = 1.68 MeV. The 8 Li sub-system in 9 Li was observed in its lowest three energy levels. The spectroscopic factors derived from a DWBA analysis are fairly consistent in trend with model calculations. The understanding of the N = 6 sub-shell closure from the spectroscopic information and neutron separation energies is discussed. © 2007 Elsevier B.V.

We report here on experiments with radioactive 21 Na and 7 Be beams performed by Colorado School of Mines students at the ISAC facility of TRIUMF and the Holifield Radioactive Ion Beam Facility (HRIBF) of ORNL. At TRIUMF, the DRAGON recoil separator and its segmented BGO array were used to investigate higher energy resonances in the reaction H( 21 Na, γ) 22 Mg. Using the HRIBF we performed an experiment with a 7 Be ion beam to measure scattering off Hydrogen and Carbon. Both elastic 7 Be + p scattering and for the first time resonant inelastic scattering 7 Be(p, p′) 7 Be ∗ were observed.

Nuclear reactions play a key role in understanding nucleosynthesis in stars. Recoil mass spectrometers such as DRAGON are well suited to study reactions with respect to astrophysical production because of direct detection of reaction products. Here we present the first stage of an experiment running at the recoil mass spectrometer DRAGON at the ISAC/TRIUMF facility in Vancouver, Canada, to study the reaction 40Ca(α, γ)44Ti at astrophysically relevant energies. This reaction is one of the key reactions for production of 44Ti, which has been identified in young supernova remnants by space based γ-ray telescopes onboard COMPTEL and INTEGRAL. In this paper we focus on technical upgrade of DRAGON for 40Ca(α, γ)44Ti and preliminary results at resonances at Ex ∼ 9.2 MeV.

A new detector for nuclear astrophysics studies is being designed and built by TRIUMF and the University of York. The TRIUMF Annular Chamber for Tracking and Identification of Charged particles (TACTIC) is designed to detect low-energy charged particles from inverse kinematics reaction studies performed at the relevant astrophysical energies. TACTIC is a cylindrical ionisation/time-projection chamber with segmented anode strips, which allow the dE/dx of the particle to be determined along with the total energy. Information from drift times allows the particle trajectory to be reconstructed. This in turn identifies the interaction point along the beam axis and hence the centre of mass energy of the reaction. To amplify the expected weak signals, a gas electron multiplier (GEM) will be used in place of the usual Frisch grid. Full digital readout of the charge and timing of each anode strip will be achieved with flash ADC cards allowing pulse shape analysis of the signals.

We present new measurements of the charge-state distribution (CSD) of a 1.068 MeV/u C beam in He and of the 6+:5+ charge-state population ratio in the recoils of the 12C(α, γ)16O reaction, both measured at the DRAGON recoil mass spectrometer. A computer simulation to model the CSD of both beam and recoil particles in inverse-kinematics experiments is compared to data from this work and from previous work at ERNA. The simulation provides good agreement with both data sets. The results suggest that, for this fusion reaction on the Jπ = 4+ resonance at Ebeam = 1.064 MeV/u, immediately after fusion, the recoil ions contain only the nucleons and not the electrons of the target He atom.

TACTIC (TACTIC web site: http://tactic.triumf.ca) is a new detector for low-energy nuclear reactions currently under development at TRIUMF. The cylindrical ionization chamber allows three-dimensional reconstruction of particle tracks by means of a two-dimensional anode array combined with a TOF measurement of the drift electrons. In addition, the integrated charge for each pulse provides information about the energy loss of the particle and therefore allows a better identification of the nuclear species producing the track. The geometry of TACTIC covers a large angular range permitting the measurement of differential cross-sections over a large solid angle. It will be ideal for investigations of nuclear processes pertinent to the field of nuclear astrophysics.

The performance of the DRAGON recoil spectrometer at TRIUMF-ISAC has been studied using radiative capture reactions with stable beams of 12C, 20Ne, 21Ne, 23Na, 24Mg and 26Mg. Calibration of the deflection magnet measuring the beam energy was established and the beam suppression factors of the separator were investigated. Yields from six narrow resonances were measured and compared with previous results. For the 1,112.6 keV resonance in Ne 20 ( p , γ ) Na 21 our result is in disagreement with the NACRE database assignment but agrees with another previous result.

Preliminary studies in preparation for an absolute cross-section measurement of the radiative capture reaction 3 He( α , γ ) 7 Be with the DRAGON recoil separator have demonstrated beam suppression > 10 14 at the 90% confidence level. A measurement of this cross section by observation of 7 Be recoils at the focal plane of the separator should be virtually background free.

At low stellar temperatures the energy release due to the CN cycle is regulated by its slowest reaction ${}^{14}\mathrm{N}(p,\ensuremath{\gamma}){}^{15}\mathrm{O}$, the rate of which strongly depends on the subthreshold resonance at ${E}_{\mathrm{c}}.\mathrm{m}.=\ensuremath{-}504\phantom{\rule{0.28em}{0ex}}\mathrm{keV}$, which corresponds to the 6.79 MeV state in ${}^{15}\mathrm{O}$. By using the Doppler-shift attenuation method and the ${}^{3}\mathrm{He}({}^{16}\mathrm{O},\ensuremath{\alpha}){}^{15}\mathrm{O}$ reaction to populate the state, we obtained an upper limit on the lifetime of this state of $\ensuremath{\tau}l1.8\phantom{\rule{0.28em}{0ex}}\mathrm{fs}$ [68.3% confidence level (C.L.)]. In addition we measured the lifetimes of the 6.18 and 6.86 MeV states to be $\ensuremath{\tau}l2.5$ and $\ensuremath{\tau}=13.{3}_{\ensuremath{-}1.2}^{+0.9}\phantom{\rule{0.28em}{0ex}}\mathrm{fs}$, respectively (68.3% C.L.), in good agreement with the literature.

We report here a determination of the asymptotic normalization coefficient of the valence neutron in ${}^{8}$Li from a measurement of the angular distribution of the ${}^{7}$Li(${}^{8}$Li,${}^{7}$Li)${}^{8}$Li reaction at 11 MeV. Using isospin symmetry the ${}^{8}$B ANC has also been calculated and used to infer a value for ${S}_{17}(0)$ of 20.2 $\ifmmode\pm\else\textpm\fi{}$ 4.4 eV b.

4 pags., 2 figs. -- Nuclear Physics in Astrophysics V 3–8 April 2011, Eilat, Israel, We present our initial efforts with the DRAGON separator at TRIUMF facility towards obtaining the energy dependence of the astrophysical S-factor for 3He(¿, ¿)7Be reaction in the energy range of Ecm = 2 to 3 MeV that was recommended by the recent evaluations. A comparison between the existing data and our new complementary Madrid data, together with the recent theoretical calculations, is also given in the context of our ongoing work., This work has been supported by the UK STFC.

In a recent experiment performed at Triumf using the Dragon 0° spectrometer and its associated BGO array, the complete γ-decay of the radiative capture channel below the Coulomb barrier has been measured for the first time. This measurement has been performed at two energies Ec.m. = 6.6 and 7.2 MeV. A selective contribution of the entrance spins 2+ and 3− has been evidenced which is consistent with existing results above the barrier.

The {sup 18}F(p,{alpha}){sup 15}O reaction rate is crucial for understanding the final abundance of {sup 18}F predicted by nova models. The {gamma}-ray emission in the first few hours after a nova outburst is expected to be dominated by 511 keV annihilation photons from the decay of {sup 18}F, and so understanding its production can provide important constraints on the conditions during the outburst when compared with observations. Results are presented from the lowest-energy direct measurement to date, performed at the Isotope Separator and Accelerator radioactive beam facility at the TRIUMF laboratory, Canada. Cross section measurements at center-of-mass energies of 250, 330, 453, and 673 keV are obtained and the results compared to previous data and R-matrix calculations. The implications for the overall reaction rate in the context of nova explosions have been discussed.

Observations from gamma ray telescopes indicate that most of the galactic 26Al originates in massive stars. Several sites have been discussed for its production, including proton burning in the winds of very massive stars, and the later, explosive burning stages of these stars. Observations from the RHESSI and INTEGRAL missions currently seem to point to the latter scenario. In the advanced burning stages of massive stars the presence of neutrons becomes an important factor in nuclear reaction networks, so in addition to the 26Al(p,¿) 27Si reaction the neutron capture reactions 26Al(n,p) 26Mg and 26Al(n,¿) 23Na can lead to the destruction of 26Al, and thus alter the observed 26Al abundance. NEURAL is a detector design to measure the excitation functions of these reactions over a wide range of energies. 26Al targets implanted at TRIUMF will be exposed to a pulsed neutron beam at the neutron time-of-flight facility at LANSCE (Los Alamos Neutron Science CEnter). NEURAL is designed to detect all charged reaction products, combining a time projection chamber for the heavy ions, and Si detectors for the light particles mounted around the target. A first prototype has been built and partially tested at TRIUMF and LANSCE in December 2009.

The lowest-energy resonance in the $^{23}\mathrm{Mg}$($p,\ensuremath{\gamma}$)$^{24}\mathrm{Al}$ reaction, which is dominant at classical nova temperatures, has been measured directly for the first time using the DRAGON recoil spectrometer. The experiment used a radioactive $^{23}\mathrm{Mg}$ beam (mixed within a significantly stronger $^{23}\mathrm{Na}$ beam) of peak intensity $5\ifmmode\times\else\texttimes\fi{}{10}^{7}$ $\mathrm{s}{}^{\ensuremath{-}1}$, at the ISAC facility at TRIUMF. We extract values of ${E}_{R}={485.7}_{\ensuremath{-}1.8}^{+1.3}$ keV and $\ensuremath{\omega}\ensuremath{\gamma}={38}_{\ensuremath{-}15}^{+21}$ meV from our data (all values in the center-of-mass frame unless otherwise stated). In addition, the experiment prompted a recalculation of the $Q$ value for this reaction based on a revision of the $^{24}\mathrm{Al}$ mass. The effect on the uncertainties in the quantities of ejected $^{22}\mathrm{Na}$ and $^{26}\mathrm{Al}$ from oxygen-neon classical novae is discussed.

The {sup 15}O({alpha},{gamma}){sup 19}Ne reaction plays a role in the ignition of type I x-ray bursts on accreting neutron stars. The lifetimes of states in {sup 19}Ne above the {sup 15}O+{alpha} threshold of 3.53 MeV are important inputs to calculations of the astrophysical reaction rate. These levels in {sup 19}Ne were populated in the {sup 3}He({sup 20}Ne,{alpha}){sup 19}Ne reaction at a {sup 20}Ne beam energy of 34 MeV. The lifetimes of six states above the threshold were measured with the Doppler-shift attenuation method. The present measurements agree with previous determinations of the lifetimes of these states and in some cases are considerably more precise.

Directly measuring nuclear astrophysics reactions presents unique challenges. Low energy reaction products and small reaction cross sections are just two of the issues that the TACTIC detector addresses. TACTIC is the TRIUMF Annular Chamber for Tracking and Identification of Charged-particles detector being developed by TRIUMF and the University of York, UK. TACTIC is a cylindrical, active-target TPC providing high detection efficiency; a shielding cathode traps the ionization created by the beam and allows for higher intensities than typical TPCs. The 480 anode signals are collected through custom preamplifiers, digital electronics and acquisition systems. Acquisition and analysis software is also undergoing extensive development. Amplification of the small signals is accomplished using a Gas Electron Multiplier (GEM). The fill gas, He-CO2, provides both particle detection and a homogeneous, variable-thickness target for studying reactions on αs, such as 8Li(α,n)11B. A preliminary study of this flagship reaction was carried out in June 2009 and the results are providing feedback into the development of the final detector and infrastructure.

Ion tracking is still an unusual detection method in nuclear physics. TACTIC (TRIUMF annular chamber for tracking and identification of charged particles) is suitable for tracking low-energy ejectiles. The cylindrical design allows for an electrical separation of target and drift region without hindering the ejectiles to enter the drift region. The first experiment with radioactive beam – the reaction 8Li(α,n)11B which is important for the α-process in neutrino-driven supernova winds – took place in June '09. Since no off-the-shelf analysis tools and methods are available for this kind of tracking, TRIUMF's TACTIC group developed graphical tool for analysing data that can also be used for other modern nuclear physics detectors.

The decay rate of 22Na implanted in aluminium has been measured at room temperature and at 10 K. The rate should increase by 40% according to Rolfs (2006 Public Lecture for SLENA (Kolkata, India)) and by about 6% according to Limata et al (2006 Eur. Phys. J. A 28 251). In the latter publication, an increase of only 1.2 ± 0.2% has been measured and the deviation has been assigned to an incomplete implantation of 22Na in the palladium sheet. Contrary, the source used for our measurements has been made by a 70 MeV proton beam penetrating an aluminum sheet, therefore the 22Na was produced deep inside the metal and the full effect should be visible when cooling the sample. We did not see an enhanced decay rate within the precision limit (0.04%) of our measurement.

The s-wave neutron fraction of the 0 + levels in 12Be has been investigated for the first time through the 11Be( d , p ) transfer reaction using a 5 A MeV 11Be beam at TRIUMF, Canada. The reaction populated all the known bound states of 12Be. The ground state s-wave spectroscopic factor was determined to be 0.28 − 0.07 + 0.03 while that for the long-lived 0 2 + excited state was 0.73 − 0.40 + 0.27 . This observation, together with the smaller effective separation energy indicates enhanced probability for an extended density tail beyond the 10Be core for the 0 2 + excited state compared to the ground state.

An experiment to measure the 18F(p,a)15O cross section at low centre of mass energies has been performed with the TRIUMF-UK Detector Array (TUDA) facility at TRIUMF. Measurements of the 18F(p,a)15O reaction rate at four separate centre of mass energies; 665 keV, 430 keV, 330 keV and 250 keV, were carried out. The main goal of the experiment was the measurement of the 18F(p,a)15O cross section between 250 keV and 300 keV to help constrainthe contribution to the reaction rate from nearby states and determine the effect of interference on the overall 18F(p,a)15O reaction rate from the proposed low lying 3/2+ states with the higher 664.7 keV 3/2+ state. A high intensity 18F beam (5x106 pps) was used to bombard a 31.61.9 mg.cm􀀀2 polyethylene target within the TUDA scattering chamber at the four centreof mass energies. Four highly segmented silicon strip detector arrays were used for coincident detection of the reaction products. Preliminary results will be presented.