The development of a new charged particle reaction spectroscopy station, IRIS, at ISAC II TRIUMF is described. The facility will be used for studying transfer reactions and inelastic scattering of ...rare isotopes in inverse kinematics.
The structure of the unbound nucleus
13
Be is important for understanding the Borromean, two-neutron halo nucleus
14
Be. The experimental studies conducted over the last four decades are reviewed in ...the context of the beryllium chain of isotopes and some significant theoretical studies. The focus of this paper is the comparison of new data from a
12
Be(d,p) reaction in inverse kinematics, which was analyzed using Geant4 simulations and a Bayesian fitting procedure, with previous measurements. Two possible scenarios to explain the strength below 1 MeV above the neutron separation energy were proposed in that study: a single p-wave resonance or a mixture of an s-wave virtual state with a weaker p- or d-wave resonance. Comparisons of recent invariant mass and the (d,p) experiments show good agreement between the transfer measurement and the two most recent high-energy nucleon removal measurements.
Pulse-stretching out of the CANREB EBIS Cavenaile, M.; Charles, C.R.J.; Kester, O. ...
Journal of physics. Conference series,
05/2024, Letnik:
2743, Številka:
1
Journal Article
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Abstract The CANadian Rare isotope facility with Electron-Beam ion source (CANREB) at TRIUMF is set to deliver rare isotope beams in high charge states. In the Electron Beam Ion Source (EBIS) ions ...are charge-bred by collisions with an electron beam of up to 500 mA. A strong magnetic field (up to 6T) maximizes the overlap between ions and electron beam and increases the breeding efficiency. Ion confinement is maintained by a combination of an electrostatic field and the electron beam space-charge potential. Ions are released by lowering the trapping potential with a step function. The system is operated at a pulse repetition frequency up to 100 Hz. Due to the short trap length, this fast extraction scheme produces pulses shorter than 10 µs with high instantaneous rates that can saturate detectors in experiments. Stretching the pulse can be done using a slowly varying voltage function to modify trap electrode potentials instead of a step function. The ideal function produces a pulse with a flat top distribution and can be calculated by knowing the ion energy distribution inside the trap. The latest pulse-stretching results will be discussed including the latest pulse duration up to 1.4 ms that have been produced. The slow extraction scheme has also been used for a measurement of the effective energy distribution of the ions inside the trap.
Changes in shell closures through nucleon transfer and nucleon knockout reactions as spectroscopic probes are discussed. The intruder s-orbital in the ground and excited states of
12Be is studied ...through the
11Be(d,p) reaction. Signature of the
0
2
+
long-lived state having an s-wave halo-like structure in
12Be is observed. One-neutron knockout from
24O shows a large spectroscopic factor for the s-orbital thereby establishing it as a new doubly magic nucleus at the drip-line.
Model predictions of X-ray burst ashes and light curves depend on the composition of the material accreted from the companion star, in particular the abundance of CNO elements. It has previously been ...pointed out that spallation in the atmosphere of the accreting neutron star can destroy heavy elements efficiently. In this work we study this spallation using a realistic reaction network that follows the complete spallation cascade and takes into account not only destruction, but also production of elements by the spallation of heavier species. We find an increased survival probability of heavier elements compared to previous studies, resulting in significantly higher CNO abundances. We provide resulting compositions as a function of accretion rate, and explore their impact on 1D multi-zone X-ray burst models. We find significant changes in the composition of the burst ashes, which will affect the thermal and compositional structure of accreted neutron star crusts.
A systematic study of shell closures around N and Z=40–60 through beta decay Q-values, one nucleon separation energies and excited states is presented for different isospin chains. Shell closure at ...N=40 is found to be absent in neutron-rich nuclei (contrary to some existing discussions) but is indicated in nuclei with Tz⩽1 within errors. The persistence of the N and Z=50 shell closure is observed, together with evidence of sub-shell closure at N=56 in neutron-rich nuclei. The sub-shell closure at Z=40, that exists for neutron-rich nuclei, is found to disappear for Tz=2.
A new radiofrequency quadrupole (RFQ) based ion beam cooler and buncher is under development for the CANadian Rare-isotope facility with Electron Beam ion source (CANREB) project at TRIUMF. The ...CANREB project requires an RFQ buncher that will efficiently accept continuous beams of rare isotopes from either the Advanced Rare IsotopE Laboratory (ARIEL) or Isotope Separator and ACcelerator (ISAC) target by way of a high resolution magnetic spectrometer, with energies up to 60keV and deliver bunched beams to an electron beam ion source (EBIS) for charge breeding. The energy of the bunched beam delivered to the EBIS will be adjustable to match the requirements of the existing post acceleration infrastructure. The CANREB RFQ incorporates design considerations to facilitate ease of use over a wide range of ion masses, and is intended to accommodate incident beam rates as high as 108pps, delivering beam bunches at 100Hz. An overview of the CANREB RFQ design concept will be presented, informed by results from both ion optical simulations as well as commissioning efforts with other beam cooler and buncher devices. Simulation results indicate that the design is well suited to deliver high quality bunched beams with high efficiency with as many as 106 ions per bunch.
CANREB EBIS commissioning at TRIUMF Schultz, B.E.; Charles, C.R.J.; Cavenaile, M. ...
Journal of physics. Conference series,
04/2022, Letnik:
2244, Številka:
1
Journal Article
Recenzirano
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Abstract
The Canadian Rare Isotope facility with Electron Beam ion source (CANREB) is an essential part of the Advanced Rare IsotopE Laboratory (ARIEL) presently under construction at TRIUMF. CANREB ...was recently commissioned and can accept stable or rare isotope beams from a variety of ion sources, delivering high purity beams of highly charged ions (HCI) to experiments. The injected beams are bunched using a radiofrequency quadrupole cooler-buncher and energy adjusted using a pulsed drift tube for injection into the electron beam ion source (EBIS) charge state breeder. The EBIS is designed for a maximum electron beam current of 500 mA and a maximum magnetic field of 6 T. Ions with energies up to 14 keV can be injected and HCI with mass-to-charge
(A/q)
ratios 3 ⩽
A/q ⩽
7 can be charge bred and extracted. The HCI are A/q-selected using a Nier-type spectrometer before being transported to the ISAC linac for post-acceleration. Results from CANREB beam commissioning with focus on the EBIS will be presented.
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