Related Papers
A hybrid surface arc discharge ion source to produce ultra pure Ca+2 beams for 40Ca(α,γ)44Ti reaction studies at ISAC/TRIUMF
ISAC is an accelerator facility primarily dedicated to astrophysical studies. Off-line and online ion sources provide up to 65 keV of stable and radioactive beams to the ISAC accelerators. Initial acceleration is done via a constant velocity radio frequency quadrupole that requires 2 keV/u. Then the beam is further accelerated to 1.5 MeV/u at ISAC-I and 6.5 MeV/u at ISAC-II. To study radiative capture reactions relevant for astrophysics, the recoil mass spectrometer DRAGON was built in the experimental area. 40Ca(α,γ)44Ti is identified as one of the key reactions in supernovae to produce 44Ti and is given highest priority. For this experiment, an ultrapure Ca+2 beam was requested from the off-line ion source. Initial tests showed that, when using conventional ion sources, 40Ar and 40K are the impurities that are most difficult to eliminate. In order to overcome this problem, a new concept was needed and the hybrid surface arc discharge ion source was born. The hybrid surface ion source consists of a small surface ionizer and an arc discharge placed in a solenoid field. A very low ratio of 40Ar/40Ca=8 x10−5 was achieved with this new source and the experiment was completed successfully. The source is described in detail and its performance is discussed in this article.
Production of intense radioactive beams at ISAC using low-energy protons
A proof-of-principle approach for the production of intense (~108/s) radioactive ion beams, which differs from the standard ISOL (Isotope Separation On-Line) technique, has been demonstrated successfully using 11C at the TRIUMF laboratory. This approach uses 13 MeV protons produced by a medical cyclotron and should be useful for a range of radioisotopes of interest to the nuclear astrophysics research programme.
Multichannel R-matrix analysis of elastic and inelastic resonances in the 21Na + ρ compound system
A multichannel R-matrix formalism was used to fit 21Na + p resonant elastic and inelastic scattering data taken at the TRIUMF UK detector array facility at TRIUMF-ISAC. Five resonances were observed corresponding to states in 22Mg above the proton threshold. Four of these corresponded to states seen in previous transfer reaction studies where firm spin-parity assignments could not be made. One new resonance, previously unobserved in any reaction, was also seen. Where possible, resonance energies, partial widths, and spin-parity values of these resonances were extracted. The correspondence between these states and possible analogs in the mirror nucleus 22Ne is discussed, as well as the relation to T = 1 states in the nucleus 22Na.
Multichannel R-matrix analysis of elastic and inelastic resonances in the 21Na+p compound system
The structure of the radionuclide 22Mg has received much attention in recent years by both experimentalists and theorists because of its role in determining the properties of astrophysical reaction rates relating to the production of 22Na in explosive stellar scenarios.
Radioactive Beams
(January 2006 - Canadian Chemical News article)