Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Measurements of pion-helium total cross sections at energies from 51 to 105 MeV

Technical Report ·
DOI:https://doi.org/10.2172/7329785· OSTI ID:7329785
Measurements of ..pi../sup + -/-/sup 4/He total cross sections have been made at energies from 51 to 105 MeV using a superfluid /sup 4/He target at the Low Energy Pion channel of the LAMPF accelerator in Los Alamos. Pions were selected with either a DISC counter or a time-of-flight system. The scattered pions were detected by a series of circular plastic scintillation counters using standard transmission techniques. The resulting partial removal cross sections were extrapolated to zero solid angle after being corrected for Coulomb effects, pion decay, accidental counts, counter absorption and efficiencies, and statistical correlations. The resulting statistical errors were generally approximately 3-5 percent. The measured total cross sections were found to be in good statistical agreement with previous measurements and in poor agreement with the predictions of several optical potentials in current use. Through an optical theorem the imaginary part of the forward scattering amplitude was found. The total cross sections have been used with previously-measured angular distributions through a phenomenological model to obtain the real part of the forward scattering amplitude at four energies between 50 and 75 MeV. These results were found to be in good agreement with forward dispersion relation calculations.
Research Organization:
Los Alamos Scientific Lab., NM (USA)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
7329785
Report Number(s):
LA-6561-T
Country of Publication:
United States
Language:
English