A recoil separator for the measurement of radiative capture reactions

Abstract A recoil separator in combination with a windowless gas target has been designed for the measurement of the radiative capture reaction p( 7 Be , γ) 8 B . The separator consists of momentum and velocity filters and a ΔE − E detector telescope. The setup was tested quantitatively using the p( 12 C , γ) 13 N reaction at the effective energy E cm = 841 keV. Projectile fluxes were measured directly with Faraday cups and indirectly with elastic backscattering into Si detectors, while the 13 N recoil flux was measured directly with the ΔE − E telescope. A suppression of the 12 C beam particles by a factor 2 × 10 −10 was observed when the system was tuned for the recoil 13 N's . Special emphasis was given to the charge state probabilities of the 13 N recoils. Possible improvements of the system for the measurement of other capture reactions are discussed.