H.E. Conzett

Separation of projectile and ejectile spin-orbit distortions in an L = 0 (d, 3He) reaction

Abstract Analysing powers of the l tr = 0, 31 P( d , 3 He) 30 Si , reaction and its inverse reaction have been measured. Quantities which are proportional to the entrance and exit-channel spin-orbit distortions have been constructed from these analysing powers. From these quantities the relative importance of the two spin-orbit distortions was ascertained. A DWBA analysis including D-state contributions in the 3 He wave function was conducted in order to fit the spin-separated quantities. Optical-model potential parameters used in the DWBA analysis were deduced from a study of the entrance- and exit-channel elastic scattering data.

Performance of a silicon proton polarimeter between 19 and 32 MeV

Abstract The design is presented of a proton polarimeter which combines the advantages of high scattering efficiency and good energy resolution. The polarimeter, intended for proton energies above 17 MeV, is well-suited to the study of polarisations in low-yield reactions and has been used in the measurement of triple-scattering parameters. A typical figure of merit Aσ 1 2 of ≈ 2.2 × 10 −3 and an energy resolution of approximately 100 keV fwhm at 26 MeV make the present type of polarimeter superior to others for experiments where good energy resolution is required.

THE ELASTIC SCATTERING OF POLARISED PROTONS BY 40Ar

Abstract The analysing power of 40Ar for polarised protons has been measured at energies of 25.1, 32.5 and 40.7 MeV at laboratory angles between 30° and 158°. The results are fitted with the optical-model code SEEK3 and examined for a possible L-dependence of the optical potentials. The results also provide calibration points for a p- 40Ar polarimeter.

Asymétrie du temps: Polarisation et pouvoir d'analyse dans les réactions nucléaires

Abstract Measurements of the proton polarization in the reactions 7 Li( 3 He, p ) 9 Be and 9 Be( 3 He, p ) 11 B and of the analyzing powers of the inverse reactions, initiated by polarized protons at the same c.m. energies, show significant differences which imply the failure of the polarization-analyzing-power theorem and, prima facie , of time-reversal invariance in these reactions. The reaction 2 H( 3 He, p ) 4 He and its inverse have also been investigated and show some smaller differences. A discussion of the instrumental asymmetries is presented.

Diffusion des protons polarisés sur 24Mg, 27Al et 32S et anomalies dans la région des résonances géantes de l'25Al, du 28Si et du 33C1

Abstract Differential cross-section and analyzing power angular distributions have been measured for the elastic scattering of polarized protons on 24 Mg, 27 Al and 32 S between 13 and 27 MeV. An optical model analysis has been performed and the spin-orbit potentials display significant variations in the giant resonance region of 25 Al, 28 Si and 33 C1. The 24 Mg and 32 S data have been examined in a phase-shift analysis.

Extreme values of the spin polarization analyzing power in nuclear reactions

Abstract States of maximum possible polarization are investigated for ensembles of spin- 1 2 and spin-1 particles in nuclear reactions. General criteria for extreme values of some components of the analyzing power are given and applied to the formulae for the observables of reactions with various spin spaces. Experimental data relevant to possible extreme values are discussed.

DEPOLARIZATION AND THE SPIN-SPIN INTERACTION IN p-9Be ELASTIC SCATTERING

Abstract We have determined the D-parameter to be less than 1.0 at four angles in p-9Be elastic scattering at 25 MeV. These results strengthen considerably the evidence for the existence of a nucleon-nucleus spin-spin interaction.

SEMI-CONDUCTOR PROBE FOR INVESTIGATING ACCELERATOR BEAM PULSES

Abstract An instrument which makes possible the investigation of individual beam pulses from a cyclotron is described. It utilizes a fully depleted diffused-silicon junction detector of 100–200 microns thickness. The detector characteristics of fast charge collection time (∼1 ns) and of inherent amplification are important in this application. Examples of the detector system response to beams from the Berkeley sector-focused cyclotron are presented.

Is the 12C(d,d0) reaction a good polarization standard?☆

Abstract The suitability of d −12C elastic scattering as a deuteron polarization analyzer is examined.

Measurement of the Proton Analyzing Power in the p-d Breakup Reaction

We report in this paper on the measurement of the proton analyzing power Ay in the 2H(,p)d* reaction at Ep = 22.7 MeV,}which corresponds to the same center of mass energy as that in the 1H(,p)d* reaction reported by Conzettl) Here, d* denotes final-state np pairs with relative energy Enp ≤ 1 MeV, in both the singlet and triplet states. Previously there had been measurements of the vector analyzing power in the 2H(,2p)n (ref.2) and 1H(,2p)n (ref.3) transitions to the np final-state interaction (FSI) region at Ep = 10.5 MeV and Ed = 12.2 MeV, respectively. In both instances the analyzing powers were very small or consistent with zero. The higher energy results at Ed = 45.4 McV1) showed values of Ay reaching 0.15±0.02. The exact three-body calculations4,5), which have been successful in fitting N-d breakup cross sections, have so far been limited to S-wave N-N input interactions and, thus, provide no polarization.