Pion absorption processes. [32 to 74 MeV]

Technical Report · Tue Apr 01 04:00:00 EST 1980

DOI:https://doi.org/10.2172/5457532· OSTI ID:5457532

Doss, K G.R.

Proton and deuteron production from low-energy pion absorption in light nuclei leading to discrete and continuum states were measured. The LEP beam line at LAMPF was used with a stack of 8 intrinsic germanium crystals. The proton energy spectra are in general characterized by a broad bump at an energy approximately corresponding to ..pi../sup +/d ..-->.. pp reaction kinematics, suggestive of pion absorption on 2 nucleons. The energy-integrated cross-section for production of deuterons has an angular distribution similar to that for production of protons. The dependence of the total pion absorption cross-section on A is explained using a semi-classical model for pion transport in nuclei. The (..pi../sup +/,p) as well as (..pi../sup +/,d) reactions generally favor transitions involving larger angular momentum transfer to the residual nucleus when states of similar nuclear structure are considered. The low-energy excitation spectra from the (..pi../sup +/,p) reaction are similar to the spectra from (p,d) reaction on /sup 12/C and /sup 13/C. However, a calculation of the (..pi.. = ,p) cross-section using the measured (p,d) reaction with the formulation of Wilkin to relate the two reactions is in moderate disagreement with the measured (..pi../sup +/,p) cross-sections. The excitation spectra from the (..pi../sup +/,p) reaction indicte the importance of two-step processes for the reaction. The (..pi../sup +/,d) reaction leading to the ground state of -- residual nucleus has been seen for /sup 7/Li, /sup 12/C, and /sup 13/C targets. The measured cross section for the /sup 12/C(..pi../sup +/,d)/sup 10/C reaction to the 2/sup +/ state is much higher than that for the ground state. For the case of /sup 18/O, no counts were seen for excitation energy of < 10 MeV, at a sensitivity of approx. 100 nb/sr count. These features indicate a possible failure of the model of Betz and Kerman for the (..pi../sup +/,d) reaction.

• Research Organization: Carnegie-Mellon Univ., Pittsburgh, PA (USA). Dept. of Physics
• DOE Contract Number: AC02-76ER03244
• OSTI ID: 5457532
• Report Number(s): COO-3244-72
• Country of Publication: United States
• Language: English

Related Subjects

651325* -- Nuclear Properties &amp; Reactions
A=6-19
Experimental-- Nuclear Reactions &amp; Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ABSORPTION
ALKALI METAL ISOTOPES
ALPHA DECAY RADIOISOTOPES
ANGULAR DISTRIBUTION
BARYONS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BORON 10 TARGET
BORON 8
BORON ISOTOPES
CARBON 10
CARBON 11
CARBON 12
CARBON 12 TARGET
CARBON 13 TARGET
CARBON ISOTOPES
CHARGED PARTICLE DETECTION
CHARGED PARTICLES
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DATA
DATA FORMS
DETECTION
DEUTERONS
DISTRIBUTION
EFFICIENCY
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTARY PARTICLES
ENERGY RANGE
ENERGY SPECTRA
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
FERMIONS
GE SEMICONDUCTOR DETECTORS
GRAPHS
HADRON REACTIONS
HADRONS
HIGH-PURITY GE DETECTORS
INFORMATION
ISOTOPES
KINETICS
LIGHT NUCLEI
LITHIUM 5
LITHIUM 6
LITHIUM 7 TARGET
LITHIUM ISOTOPES
MEASURING INSTRUMENTS
MESON REACTIONS
MEV RANGE
MEV RANGE 10-100
MINUTES LIVING RADIOISOTOPES
NITROGEN 13
NITROGEN 14 TARGET
NITROGEN ISOTOPES
NUCLEAR REACTION KINETICS
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
NUMERICAL DATA
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
OXYGEN 16
OXYGEN 16 TARGET
OXYGEN 18 TARGET
OXYGEN ISOTOPES
PION DETECTION
PION REACTIONS
PROTON SPECTRA
PROTONS
RADIATION DETECTION
RADIATION DETECTORS
RADIOISOTOPES
REACTION KINETICS
SECONDS LIVING RADIOISOTOPES
SEMICONDUCTOR DETECTORS
SPECTRA
STABLE ISOTOPES
TARGETS