Production Cross Sections of Fragments from Beams of 400{endash}650 MeV per Nucleon {sup 9}Be, {sup 11}B, {sup 12}C, {sup 14}N, {sup 15}N, {sup 16}O, {sup 20}Ne, {sup 22}Ne, {sup 56}Fe, and {sup 58}Ni Nuclei Interacting in a Liquid Hydrogen Target. I. Charge Changing and Total Cross Sections

Journal Article · Tue Dec 01 00:00:00 EST 1998 · Astrophysical Journal

DOI:https://doi.org/10.1086/306445· OSTI ID:324909

Webber, W R ^[1]; Kish, J C; Rockstroh, J M ^[2]; Cassagnou, Y; Legrain, R; Soutoul, A; Testard, O ^[3]; Tull, C ^[4]

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1. Astronomy Department, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003 (United States)
2. Spectra Research Incorporated, Portsmouth, NH 03820 (United States)
3. Service d`Astrophysique, Cen. Saclay, CEDEX (France)
4. Lawrence Berkeley Laboratory, University of California, Berkeley, CA 94720 (United States)

We have measured the charge changing cross sections from 10 individual beams of isotopes from 8 different nuclei between Be and Ni which were accelerated to energies from 400{endash}650 MeV nucleon{sup {minus}1} at the SATURNE Accelerator in France in 1993 and 1994. These nuclei interacted in a 1.52 g cm{sup {minus}2} thick liquid hydrogen target and the fragments were observed. This is the first use of a pure hydrogen target to measure cross sections that has a thickness approximating the amount of hydrogen traversed by cosmic rays in our Galaxy. Several of the beam charges such as {sup 9}Be, {sup 11}B, {sup 15}N, and {sup 22}Ne have not had their fragmentation cross sections measured previously. The cross sections from the {sup 12}C, {sup 14}N, {sup 16}O, {sup 20}Ne, {sup 56}Fe, and {sup 58}Ni beams are compared with earlier measurements by our group using a CH{sub 2} {minus} C target subtraction technique to determine the hydrogen cross sections. The overall agreement between the new measurements and the earlier measurements using CH{sub 2} {minus} C subtraction is excellent with a systematic consistency between measurements of 3{percent}{endash}5{percent}. Using these new cross sections the predictions of both the B/C and {ital Z} = (21{endash}23)/Fe ratios at {approximately}1 GeV nucleon{sup {minus}1} now agree with {ital HEAO} measurements to {approximately}1{percent}{endash}2{percent}, thus obviating the need for truncation of the exponential path length distribution path length distribution that is expected from uniform propagation models. Also, these new charge changing cross sections along with the isotopic cross sections reported in paper two of this series, define the production of cosmic-ray beryllium and boron nuclei in the galaxy and also the secondary isotopes {sup 10}Be, {sup 13}C, {sup 14}N, {sup 15}N, {sup 18}O, and all of the Fe secondary isotopes to a level of precision of 3{percent}{endash}5{percent} or better. These cross sections are important for determining the abundance of these rare isotopes and others in the cosmic-ray sources as well as tracing the detailed propagation history of cosmic rays in the Galaxy. These measurements also provide high precision cross sections for the study of the nuclear physics of the interaction process. {copyright} {ital {copyright} 1998.} {ital The American Astronomical Society}

• OSTI ID: 324909
• Journal Information: Astrophysical Journal, Vol. 508, Issue 2; Other Information: PBD: Dec 1998
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
BERYLLIUM
BORON
CARBON
NITROGEN
NEON
OXYGEN
IRON
NICKEL
COSMIC RAY PROPAGATION
COSMIC RADIATION
ISOTOPE RATIO
HYDROGEN
BERYLLIUM 9
BORON 11
CARBON 12
NITROGEN ISOTOPES
NEON ISOTOPES
OXYGEN 16
IRON 56
NICKEL 58
GEV RANGE
TOTAL CROSS SECTIONS
NUCLEAR FRAGMENTATION
NUCLEAR FRAGMENTS
ATOMIC PROCESS