Clark Goodman

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.

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.

Pion-nuclear total cross sections near the 32, sol32 resonance

Abstract The π + total nuclear cross sections for 9 Be, 12 C, 16 O, and 27 Al have been measured in the energy range 114 to 210 MeV, while π − data have been taken at 153 MeV. In the center-of-mass coordinate system the π-nucleus total cross sections reach their maximum value near the π-nucleon ( 3 2 , 3 2 ) resonance ( T π C.M. = 1.52 MeV) where they scale as A 2 3 . The measured total cross sections exhibit considerable broadening with respect to the π -nucleon resonance.

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.

Gamow-Teller sum rules and the /sup 14/C(/sup 6/Li,/sup 6/He)/sup 14/N reaction. [62 MeV]

A correlation between the (/sup 6/Li,/sup 6/He) cross sections and the Gamow-Teller strength observed previously for other targets persists in the /sup 14/C(/sup 6/Li,/sup 6/He) reaction. The total G.T. strength up to 12 MeV excitation is measured, and sum rules for the G.T. strength that depend on the LS configurations of the target state are derived. The extracted LS configuration of the /sup 14/C ground state is in serious disagreement with shell model calculations. There are several inconsistencies within our understanding of the nuclear structure and transition strengths in these nuclei, part of which is attributable to mesonic currents. Constraints are also placed upon the (/sup 6/Li,/sup 6/He) reaction mechanism. 3 figures, 2 tables.