In-flight production of an isomeric beam of 16N

Abstract

An in-flight beam of 16N 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 16N beam which resided in its excited 0.120 MeV Jπ=0− isomeric state (T1/2≈5 μs) 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 ≈30 m downstream of the production target and utilized an Al beam-stopping foil and a HPGe Clover detector. Composite 16N 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 ΔE-E telescopes. A Distorted Wave Born Approximation (DWBA) approach was coupled with the known spectroscopic information on 16N in order to estimate the relative 16N isomer yields and composite 16N 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.