1,263 research outputs found
Isotopic and velocity distributions of Bi produced in charge-pickup reactions of 208Pb at 1 A GeV
Isotopically resolved cross sections and velocity distributions have been
measured in charge-pickup reactions of 1 A GeV 208Pb with proton, deuterium and
titanium target. The total and partial charge-pickup cross sections in the
reactions 208Pb + 1H and 208Pb + 2H are measured to be the same in the limits
of the error bars. A weak increase in the total charge-pickup cross section is
seen in the reaction of 208Pb with the titanium target. The measured velocity
distributions show different contributions - quasi-elastic scattering and
Delta-resonance excitation - to the charge-pickup production. Data on total and
partial charge-pickup cross sections from these three reactions are compared
with other existing data and also with model calculations based on the coupling
of different intra-nuclear cascade codes and an evaporation code.Comment: 20 pages, 12 figures, background information on
http://www-w2k.gsi.de/kschmidt
Determination of the freeze-out temperature by the isospin thermometer
The high-resolution spectrometer FRS at GSI Darmstadt provides the full
isotopic and kinematical identification of fragmentation residues in
relativistic heavy-ion collisions. Recent measurements of the isotopic
distribution of heavy projectile fragments led to a very surprising new
physical finding: the residue production does not lose the memory of the N/Z of
the projectile ending up in a universal de-excitation corridor; an ordering of
the residues in relation to the neutron excess of the projectile has been
observed. These unexpected features can be interpreted as a new manifestation
of multifragmentation. We have found that at the last stage of the reaction the
temperature of the big clusters subjected to evaporation is limited to a
universal value. The thermometer to measure this limiting temperature is the
neutron excess of the residues.Comment: 8 pages, 6 figures, corrected some misprints in the abstract, to be
published in "Yadernaya Fizika" as a proceeding of the "VII International
School Seminar on Heavy-Ion Phyics", Dubna (Russia), May 27 - June 1, 200
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