- Conference date: 19-23 June 1978
- Location: Winnipeg, Canada
Measurements have been made of the cross section and asymmetry of the 40Ca(p↘,2p) reaction. Peaks corresponding to the knockout of protons from the 1d3/2, 1d5/2 and 2s1/2 shells are seen. By comparing the asymmetry for protons from the 2s1/2 shell with that arising from free p‐p scattering, information on spin orbit distortion effects is obtained.
This experiment was performed using a 200 MeV polarized proton beam from the TRIUMF cyclotron. The polarization and interacting of the incident beam were monitored in a polarimeter and an ion chamber. The energies and angles of outgoing protons were measured by four detector telescopes consisting of plastic scintillation counters, multi‐wire proportional chambers, and 75 mm thick × 125 mm diameter NaI (Tl) scintillation crystals. Coincidences between particles traversing detector telescopes on opposite sides of the beam line were recorded. Missing energy spectra for events with recoil momenta ∠ 0 MeV/c and ∠ 100 MeV/c are shown in Figures I(a) and I(b) respectively. In the first case, in which states with l=0 are enhanced, one can see a peak arising from protons scattered from hydrogen contamination in the target at Emiss=0 and a peak arising from knockout of 2s1/2 protons in 40Ca. In Figure I(b) states with l≠0 are enhanced and peaks corresponding to knockout of 1d3/2 and 1d5/2 protons are seen. The asymmetries of these peaks are qualitatively in agreement with what one might expect from the ’Maris’ effect. The asymmetry for protons knocked out from the 2s1/2 state is compared with the free p‐p elastic scattering asymmetry (Figure II).
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