G.E. Tripard

Measurements of ΔσL (np) between 500 and 800 MeV

Abstract A measurement of Δσ L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states, is described. Data were taken for five energies between 500 and 800 MeV, with statistical errors of ≈ 1.5 mb and an estimated normalization error of 6%. The data, combined with other results, show some evidence for an elastic I =0 spin-singlet resonance with mass ∼ 2213 MeV and width ∼ 74 MeV, or a coupled-triplet resonance with similar mass and width.

A channel-by-channel method of reducing the errors associated with peak area integration

Abstract A new method of reducing the errors associated with peak area integration has been developed. This method utilizes the signal content of each channel as an estimate of the overall peak area. These individual estimates can then be weighted according to the precision with which each estimate is known, producing an overall area estimate. Experimental measurements were performed on a small peak sitting on a large background, and the results compared to those obtained from a commercial software program. Results showed a marked decrease in the spread of results around the “true” value (obtained by counting for a long period of time), and a reduction in the statistical uncertainty associated with the peak area.

Quick polarization analyzer (QPAN)

Abstract A high count rate polarimeter for the measurement and monitoring of the polarization of an intermediate energy neutron beam has been developed. The device, QPAN, consists of a double arm telescope with adjustable copper absorbers. The asymmetry of the protons scattered from the liquid hydrogen (LH2) target is calculated from the count differential between two arms, positioned above and below the beam.

A neutron hodoscope for medium energy np scattering experiments

Abstract A 24-element plastic scintillation counter hodoscope for np elastic and total cross section measurements at LAMPF is described. Details of construction, electronics, calibration with cosmic ray muons, and a determination of absolute detection efficiency at 289 and 435 MeV are presented.

Measurement of A(nn), A(no), and A(on) for the Reaction

Angular distributions of the spin observables A/sub n//sub n/, A/sub n//sub o/, and A/sub o//sub n/ for the reaction pp..-->..d..pi../sup +/ have been measured for pion c.m. angles 30/sup 0/

P P \to D \pi^+

Angular distributions of the spin observables A/sub n//sub n/, A/sub n//sub o/, and A/sub o//sub n/ for the reaction pp..-->..d..pi../sup +/ have been measured for pion c.m. angles 30/sup 0/

in the Energy Region 500-{MeV} - 800-{MeV}

Measurements of A/sub L/L between 500 and 800 MeV and spin dependent cross sections derived from these measurements are presented for the reaction pp..--> pi..d at c.m. angles theta/sub ..pi../( of 50/sup 0/, 70/sup 0/, and 90/sup 0/. Angular distributions for A/sub S/L are also presented for energies 500, 650, and 800 MeV. These are the first measurements of spin-correlation parameters in this channel above 590 MeV, and are in substantial disagreement with theoretical predictions of the triplet amplitudes above 600 MeV.

Measurement ofAnn,Ano, andAonfor the reaction pp→dπ+in the energy region 500–800 MeV

Measurements of A/sub L/L between 500 and 800 MeV and spin dependent cross sections derived from these measurements are presented for the reaction pp..--> pi..d at c.m. angles theta/sub ..pi../( of 50/sup 0/, 70/sup 0/, and 90/sup 0/. Angular distributions for A/sub S/L are also presented for energies 500, 650, and 800 MeV. These are the first measurements of spin-correlation parameters in this channel above 590 MeV, and are in substantial disagreement with theoretical predictions of the triplet amplitudes above 600 MeV.