David Gary Mavis

The stanford polarized atomic beam target

A polarized atomic beam source was used to produce an atomic hydrogen beam which was in turn used as a polarized proton target. We measured a target density of 2×10″ atoms/cm3 and a target polarization of 0.37 without the use of r.f. transitions. These measurements indicate that a number of experiments are currently feasible with a variety of polarized target beams.

E1 and E2 Strength in 32s Observed with Polarized Proton Capture

The polarized proton capture reaction is a very powerful tool for studying the giant El resonance as well as M1 and E2 strength in nuclei. The reaction matrix elements for radiative capture can be studied thoroughly if not only the angular distributions, σ(θ), but also the analyzing powers, A(θ), of the emitted photons are observed.

El Analogue States in 90Zr Studied with Polarized Proton Capture

Studies of the 89Y(p,γ0) reaction1,2) have revealed the existence of sharp, isolated 1− analogue (IAR) resonances at Ep = 6.15 and 8.01 MeV which have been assigned isospin T> = 6 because of their narrow width and the known parent spectrum of 90Y. We have studied the same reaction with polarized protons in the regions of these two IAR’s in steps of 25 keV with a 30 keV (average) thick target. The angular distributions σ(θ) and the analyzing powers A(θ) have been analyzed according to \( 4\pi \sigma \left( \theta \right) = \sum\limits_{k = 0}^3 {{A_k}{P_k}} \left( \theta \right)and4\pi \sigma \left( \theta \right)A\left( \theta \right) = {\sum\limits_{k = 0}^3 {{B_k}{P_k}} ^1}\left( \theta \right). \).

Measurement of the Quadrupole Moment of 8 Li by use of a Polarized Beam and NMR Detection

In a separate contribution to this conference (T. Minamisono et al.) the method of producing polarized nuclei with polarized beams is described. In this paper we report an application of the method to a measurement of the quadrupole moment of 8Li.

Hyperfine Studies by use of Polarized Reactions

A new method for studying hyperfine interactions has been developed in which polarized nuclei are produced from nuclear reactions initiated with fast polarized beams of protons and deuterons. We have demonstrated that in these reactions the net polarization transferred to all residual nuclei is large enough to make possible quantitative studies of nuclear polarization and moments.

EXCITED STATES OF 4He STUDIED WITH THE POLARIZED PROTON CAPTURE REACTION

Publisher Summary This chapter discusses the excited states of 4 He studied with the polarized proton capture reaction. It presents a summary of lowest excited states of 4 He obtained from resonance analyses of and reactions. The negative parity levels are consistent in spin and approximate location with the 1p1s −1 states predicted by the shell model. Positive parity states are expected to be composed partly of 1p–1h and partly of 2p–2h excitations. For a self-conjugate nucleus such as 4 He, E1 transitions to the ground state are allowed only from T = 1, 1 − levels. The two T = 1, 1 − levels postulated at 27.k and 30.5 MeV are expected to dominate the characteristics of the EL radiation in nucleon capture reactions, which form 4 He. These states comprise the giant E1 resonance of 4 He. The presence of third and fourth degree Legendre polynomials P 3 , P 4 , in the gamma-ray angular distribution is evidence for E2 radiation, which is thought to reflect a T = 0, 2 + state in the region of 33 MeV in 4 He. The spin direction for the protons could be set either up or down by switching the rf transitions in the polarized source.