Authors
Hoffman, C. R.; Tang, T.; Avila, M.; Ayyad, Y.; Brown, K.; Chen, J.; Chipps, K. ; Jayatissa, H.; Kay, B.; Mller-Gatermann, C.; Ong, H. J.; Song, J.; Wilson, G.
Abstract
An in-flight beam of N-16 was produced via the single-neutron adding (d,p) reaction in inverse kinematics at the recently upgraded Argonne Tandem Linear Accelerator System (ATLAS) in-flight system. The amount of the N-16 beam which resided in its excited 0.120 MeV J(pi)= 0(-) isomeric state (T-1/2 asymptotic to 5 mu s) was determined to be 40(5)% at a reaction energy of 7.9(3) MeV/u, and 24(2)% at a reaction energy of 13.2(2) MeV/u. The isomer measurements took place at an experimental station asymptotic to 30 m downstream of the production target and utilized an Al beam-stopping foil and a HPGe Clover detector. Composite N-16 beam rate determinations were made at the experimental station and the focal plane of the Argonne in-flight radioactive ion-beam separator (RAISOR) with Si delta E-E telescopes. A Distorted Wave Born Approximation (DWBA) approach was coupled with the known spectroscopic information on 16N in order to estimate the relative N-16 isomer yields and composite N-16 beam rates. In addition to the observed reaction-energy dependence of the isomer fraction, a large sensitivity to the angular acceptance of the recoils was also observed.