@article{fb5379b8399d43fda1e6c545954a1ee4,
title = "Result of 21Na+p experiments at ISAC",
abstract = "Several resonances in 22Mg have been observed with a radioactive beam of 21Na impinging on a hydrogen target at ISAC. Both elastic scattering as well as radiative capture have been investigated. Some results together with the experimental methods used will be reported.",
author = "Azuma, \{R. E.\} and S. Bishop and L. Buchmann and Chatterjee, \{M. L.\} and Chen, \{A. A.\} and D'Auria, \{J. M.\} and T. Davinson and S. Engel and Fulton, \{B. R.\} and D. Gigliotti and U. Greife and D. Groombridge and D. Hunter and A. Hussein and D. Hutcheon and C. Jewett and King, \{J. D.\} and N. Khan and S. Kubono and Laird, \{A. M.\} and M. Lamey and R. Lewis and L. Ling and W. Liu and S. Michimasa and Murphy, \{A. S.\} and A. Olin and D. Ottewell and P. Parker and J. Pearson and I. Roberts and A. Robinson and Rogers, \{J. G.\} and G. Roy and C. Ruiz and F. Sazazin and Shotter, \{A. C.\} and H. Sprenger and F. Strieder and P. Walden and Woods, \{P. J.\} and C. Wrede",
note = "Funding Information: As Fig. 3 shows for measurements at high energies, like the 825 keV resonance, the single detector spectrum has two distinct peaks at the high energy side, one resulting from the recoil particles, the higher energy peak coming from beam particles at the exact energy of the beam (“leaky beam”). The spatial distribution shows the recoil events well centered on the DSSSD. Since the leaky beam can be separated in the single recoil detector, a recoil to beam suppression including the detector has been found to be greater than 10-l” for the radiative capture resonance of 21Na+p at 825 keV. The recoil projection part of the coincidence spectrum shows that the leaky beam is removed by the y coincidence. The two-dimensional spectrum demonstrates a clear correlation between broadened recoil peak and the y energies. The y part of the coincidence spectrum events result from transitions into the ground and the first excited state of “Mg. The recoil to beam suppression ratio including y coincidences with the BGO array is estimated to be less than 10-i”. For low energies, like the 210 keV resonance, the recoil and the leaky beam are not separated anymore and one has to rely on the recoil-y efficiency to obtain results. By varying the {\textquoteleft}lNa beam energy, an excitation function over the 210 keV and 825 keV resonances were obtained in coincidence mode and also from single recoil events for the 825 keV resonance. The gas target profile has been determined by extensive measurements with stable beams while the acceptance function over the profile into the separator has been found to be constant [6]. Both the measured energy loss as well as the capacitance manometer then correlate the gas target profile to the absolute number of protons per length of the target. The position information delivered in recoil-y coincidence by the BGO array shows the resonance moving through the target with changing beam energy. The charge state fraction at each resonance has been directly measured by tuning t,he separator for different charge states at the 825 keV and 210 keV resonances. To obtain the total number of beam particles through the target, the yield has been normalized to the current measured at the entrance Faraday cup in front of the gas target before and after the run. Full transmission of the beam through the target has been tuned for at the beginning of each run, while fluctuations of the beam intensity were observed at the elastic scattering monitor during the course of each individual run. Also a 4 decay monitor at the mass slit position has proven useful in the beam normalization. For more information on the 210 keV resonance excitation function see S. Bishop et, al. [14]. In summary, it has been shown that the recoil separator DRAGON can be successfully used to detect radiative capture reactions with radioactive ions. In particular, recoil to beam suppression has been found more than adequate for this kind of reaction. The properties of the 210 and 825 keV resonances in the p(21Na,y)22Mg reaction have to be finally determined, i.e. their energies, A/ branching ratios and resonance strengths. More data as measured with DRAGON at other energies in p(21Na,y)22h1g are under analysis [14]. An additional resonance has been detected at 560 keV/u. From the available data the stellar reaction rate of 21Na(p,y)22Mg will be determined [14]. We wish to thank the TRIUMF staff. in particular the operators of the ISAC facility, for making these experiments possible. Foremost we would like to express our gratitude to Marik Dombsky for producing the 21IU a beam and to Bob Laxdal and Matte0 Passini for numerous tunes of the ISAC RFQ-DTL acce{\textquoteright} lerator. We would also like to express our thanks to Pierre Leleux and Paul Demaret (UCL, Louvain la Neuve. Belgium) for supplying (CH,), targets used in the elastic scattering experiment. We acknowledge t,he contribution of Gordon Ball, Nick Bateman, Cary Davids, Uli Giesen, Peter Jackson, Peter Lipnik, Jerry Nolen, Miguel Olivo, and Hermann Wollnick in many helpful discussions. Thanks to Herb Coombes for the design of y detector bases and signal filters, to Peter Gumplinger for configuring GEANT software used for BGO simulations and to Pierre-Andre Amuadruz for providing the data acquisition software and frequent consultations. We acknowledge the assistance of Peter Machule, Doug Preddy and Heinz Biegenzein with aspects of the equipment installation. This work was supported by the EPSRC (UK) and NSERC (Canada).",
year = "2003",
month = jul,
day = "28",
doi = "10.1016/S0375-9474(03)00688-2",
language = "English",
volume = "723",
pages = "119--126",
journal = "Nuclear Physics, Section A",
issn = "0375-9474",
publisher = "Elsevier B.V.",
number = "1-2",
}