Target and detection techniques for theN13(p,γ)14

Radioactive ion beam physics at the cyclotron research centre Louvain-la-Neuve

“…Another method which was also based on the detection of the radioactive end product of the reaction of interest (here the 13 N(d,n) 14 O reaction) consisted of detecting with well-shielded large-volume Ge detectors, the γ rays emitted in the β + decay of 14 O, implanted on a movable tape [21].…”

“…However in order to study these reactions with RIBs, inverse kinematics has to be used implying the necessity of developing hydrogen and helium targets adapted to such experiments. For the 13 N(p,γ) 14 O reaction a feasibility study using the 13 C(p,γ) 14 N reaction was conducted comparing the resonance parameters obtained in inverse kinematics with an extended gas target (thintarget yield) and with a polyethylene foil (thick-target yield), with results from normal kinematics where thin and thick 13 C targets were bombarded with protons [14]. The loss in hydrogen of the polyethylene target was determined as a function of irradiation time and beam intensity (0.5% per hour per particle nA).…”

“…In the case of the 13 N(p,γ) 14 O reaction a large volume Ge detector was preferred to NaI(Tl) detectors to record the 5.173 MeV capture γ rays [9,12,14].…”

“…2. The first result and also the first capture measurement with a radioactive ion beam was the direct determination of the 13 N(p,γ) 14 O reaction cross section which is crucial to determine the stellar conditions under which the hot CNO cycle competes with the cold CNO cycle [2,12]. In the relevant range of stellar temperatures the cross-section is dominated by the p = 0 resonance at E c.m.…”

“…This crucial reaction has been the object of further studies using the in-flight technique at Texas A&M [33], RIKEN [34] and Beijing [35], in particular on the non-resonant part. The dominant uncertainty in the 13 N(p,γ) 14 O RIB Physics at the CRC Louvain-la-Neuve reaction rate presently arises from the γ width of the 5.173 MeV state in 14 O. Shortly after these first experiments with the 13 N beam, a second important reaction was tackled.…”