J. C. Allred

Proton small angle multiple scattering at 600 MeV

Abstract The small angle multiple scattering of 600 MeV protons from targets of C, Al, Cu, Cd, and Pb has been observed using two-dimensional multiwire proportional detectors (MWPC) placed in the proton beam. Data with high statistical accuracy near zero degrees are presented for the first time. The results compared to a modified Moliere calculation agree within a few percent for the rms Gaussian angle, but the data do not decrease with angle as rapidly as the Moliere prediction for angles greater than 3 or 4 times the rms angle for the lighter targets. The deviation in the tail of the distributions is especially evident in carbon, and is attributed to the presence of nuclear scattering and the finite size of the target nucleus. The present theories are not able to reproduce these tail distributions.

Quasi-free scattering and final state interactions in the reaction 2H(p,2p)n at 585 MeV

Abstract The reaction 2 H(p,pp)n has been observed in a kinematically complete experiment at 585 MeV. A neutron-proton final state interaction was observed for an angle pair of 41°-61°. The spectral shape agrees reasonably well with the simple final state interaction theory. Quasi-free scattering was observed in the momentum spectrum for symmetric angles of 41°-41°. The spectator neutron momentum ranged from 0 to 425 MeV/ c . The simple impulse approximation using the Hulthen wave function describes the data very well out to 240 MeV/ c , at which point a sudden departure is observed.

Quasi-free scattering in proton-induced deuteron breakup at 585 and 800 MeV☆

Abstract Quasi-free scattering (QFS) has been observed in a kinematically complete p-d breakup experiment at 585 and 800 MeV. The reactions 2 H(p, 2p)n and 2 H(p, pn)p were investigated simultaneously for both symmetric and non-symmetric reaction kinematics. By employing a broad-range magnetic spectrometer, QFS was observed over a spectator momentum range from 0 to 350 MeV/ c . The spectator model with the Gartenhaus wave function describes the data well out to spectator momenta of ≈ 200 MeV/ c , above which point a significant discrepancy is observed.

Pion small-angle multiple scattering at energies spanning the (3,3) resonance

Abstract The small-angle multiple scattering of positive and negative pions has been measured for C, Al, Cu and Pb targets throughout an energy range spanning the (3, 3) resonance. The measurements were made using two-dimensional multiwire proportional counters placed in the pion beam. All previous multiple scattering data for electrons and protons as well as these new data for pions are used to recalculate the empirical terms in the Moliere theory of multiple scattering. A second-order Born approximation multiple scattering theory has been devised for spin zero particles. Modified Moliere theory gives a better fit to the experimental data than the second-order Born calculation. Because the updated Moliere theory contains much simpler equations and gives closer agreement with experiment, it is recommended in place of the more sophisticated theory for the interpretation of new experimental data.

Multi-strip scintillation counters (MSSC)

Abstract Using binary-coded light-pipe systems, we have demonstrated a single-layer, position-sensitive scintillation counter which can respond at a rate up to 10 8 Hz with a relatively small number of photomultiplier tubes. These devices may also be used as position-sensitive gamma-ray detectors.

An in-flight pion beam flux monitor

Abstract An absolute pion flux monitor has been developed which employs the detection of muons from pion decay with multiwire proportional counters. The system also provides a measure of the pion momentum, the momentum resolution, and spatial distribution of the pion beam, and is useful in the energy range below 300 MeV.

Final state interactions in deuteron breakup by protons at 585 and 800 MeV

Abstract Neutron-proton final state interactions (FSI) were observed in the deuteron breakup reaction 2H(p, 2p)n-via a kinematically complete experiment at incident proton energies of 585 and 800 MeV. Kinematic conditions were chosen which allowed the final state proton and neutron to have small relative energies; data were taken at four proton c.m. scattering angles at 800 MeV, ranging from 71° to 119° and at 94° and 106° at 585 MeV. The data are analyzed in terms of the Goldberger-Watson formalism for final state interactions, and the individual contributions of the 1S0 and 3S1 np states are determined. The 3 S 1 1 S 0 ratio is large, as expected from some reaction models. The ratio of 3S1 (almost elastic) to pd elastic cross sections is in good agreement with FSI analysis.

Tune-up of the LAMPF high-energy pion channel

Abstract The LAMPF high-energy pion channel was tuned by tracing individual particles through the channel using multiwire proportional counters. Beam spot sizes, divergences, dispersions, and correlations between angle, displacement, and momentum were measured and optimized in an on-line least-squares search. The results are compared to predictions made by the TRANSPORT computer code, and it is found that the experimental results are in agreement with computer calculations.

Reaction mechanisms and isospin effects for the π±+D→p+π±+n processes at Pπ=340 MeV/c

Abstract The first kinematically complete counter measurements of the D( π ± , pπ ± )n reactions in the Δ(1232) region are reported. Calculations based on low order diagrams compare well with the data. The ratio pπ + /pπ − depends strongly on the spectator particle momentum, and its behavior is qualitatively reproduced.

Neutron-proton final state interaction in p-d breakup at Ep = 585 MeV

Abstract The first observation of the neutron-proton final-state interaction above E p = 200 MeV is reported. The cross section is larger than expected from lower-energy data and pole graph considerations.