Research with the EN Tandem accelerator

A time-differential recoil-into-vacuum experiment was performed on the first-excited 2+ state of 20O. For this purpose the 3H(18O,p)20O reaction was used at E(18O) =24.5 MeV. At this energy there is a local maximum in the reaction yield and the p-γ angular correlation has a large anisotropy. For this work the plunger system described in the Annual Report 1977 was used. Gamma rays corresponding to the decay of the 2+1 state were observed as a function of plunger distance in coincidence with protons detected at O0 to the beam direction in a 1.5 mm thick Si surface-barrier detector. The γ-rays were detected in six 12.7 cm diameter by 12.7 cm long NaI(Tl) scintillation detectors, two at 450 and four at 900 to the beam direction. For this purpose two of the 900 detectors were positioned out of the horizontal detector plane at an angle of 450. (Auth.)