Abstract
Velocity correlations of intermediate mass fragments (IMFs), produced in collisions of Au+Au at 100, 150, 250, and 400 A.MeV beam energy, are extracted from measurements with the FOPI (phase I) detector system at SIS in GSI Darmstadt. The IMF correlation functions of peripheral and semi-central events are found to be strongly affected by the collective sideward motion of nuclear matter. The sideflow causes an enhancement of correlations at small relative velocities. This enhancement results from the mixing of differently azimuthally oriented events; it vanishes if the events are rotated into a unique reaction plane. Selecting violent central collisions, the comparison of the data with a Coulomb dominated final-state interaction model points to a radius of the expanding and multifragmenting source of R{sub s}{approx_equal}13 fm for 100 A.MeV which appears shrinking by 20% when increasing the projectile neergy to 400 MeV per nucleon. The deduced source radii are found to depend on the radial explosion energy used in the model. The inclusion of such collective expansion is necessary for a reasonable description of the experimental single-particle spectra of the IMFs. The unique Coulomb suppression of small relative IMF velocities, found for the given beam energy range, is attributed to rather constant
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Kotte, R;
Moesner, J;
[1]
Kaempfer, B;
[1]
FOPI Collaboration
- Forschungszentrum Rossendorf e.V. (FZR), Dresden (Germany)
Citation Formats
Kotte, R, Moesner, J, Kaempfer, B, and FOPI Collaboration.
Interplay of collective flow phenomena and velocity correlations of intermediate-mass fragments in collisions of Au + Au at E = 100 - 400A.MeV.
Germany: N. p.,
1994.
Web.
Kotte, R, Moesner, J, Kaempfer, B, & FOPI Collaboration.
Interplay of collective flow phenomena and velocity correlations of intermediate-mass fragments in collisions of Au + Au at E = 100 - 400A.MeV.
Germany.
Kotte, R, Moesner, J, Kaempfer, B, and FOPI Collaboration.
1994.
"Interplay of collective flow phenomena and velocity correlations of intermediate-mass fragments in collisions of Au + Au at E = 100 - 400A.MeV."
Germany.
@misc{etde_10125525,
title = {Interplay of collective flow phenomena and velocity correlations of intermediate-mass fragments in collisions of Au + Au at E = 100 - 400A.MeV}
author = {Kotte, R, Moesner, J, Kaempfer, B, and FOPI Collaboration}
abstractNote = {Velocity correlations of intermediate mass fragments (IMFs), produced in collisions of Au+Au at 100, 150, 250, and 400 A.MeV beam energy, are extracted from measurements with the FOPI (phase I) detector system at SIS in GSI Darmstadt. The IMF correlation functions of peripheral and semi-central events are found to be strongly affected by the collective sideward motion of nuclear matter. The sideflow causes an enhancement of correlations at small relative velocities. This enhancement results from the mixing of differently azimuthally oriented events; it vanishes if the events are rotated into a unique reaction plane. Selecting violent central collisions, the comparison of the data with a Coulomb dominated final-state interaction model points to a radius of the expanding and multifragmenting source of R{sub s}{approx_equal}13 fm for 100 A.MeV which appears shrinking by 20% when increasing the projectile neergy to 400 MeV per nucleon. The deduced source radii are found to depend on the radial explosion energy used in the model. The inclusion of such collective expansion is necessary for a reasonable description of the experimental single-particle spectra of the IMFs. The unique Coulomb suppression of small relative IMF velocities, found for the given beam energy range, is attributed to rather constant averaged next-neighbour distances left angle d{sub IMF} right angle =8.6{+-}0.2 fm of the IMF charge centers within the source at break-up time. (orig.)}
place = {Germany}
year = {1994}
month = {Sep}
}
title = {Interplay of collective flow phenomena and velocity correlations of intermediate-mass fragments in collisions of Au + Au at E = 100 - 400A.MeV}
author = {Kotte, R, Moesner, J, Kaempfer, B, and FOPI Collaboration}
abstractNote = {Velocity correlations of intermediate mass fragments (IMFs), produced in collisions of Au+Au at 100, 150, 250, and 400 A.MeV beam energy, are extracted from measurements with the FOPI (phase I) detector system at SIS in GSI Darmstadt. The IMF correlation functions of peripheral and semi-central events are found to be strongly affected by the collective sideward motion of nuclear matter. The sideflow causes an enhancement of correlations at small relative velocities. This enhancement results from the mixing of differently azimuthally oriented events; it vanishes if the events are rotated into a unique reaction plane. Selecting violent central collisions, the comparison of the data with a Coulomb dominated final-state interaction model points to a radius of the expanding and multifragmenting source of R{sub s}{approx_equal}13 fm for 100 A.MeV which appears shrinking by 20% when increasing the projectile neergy to 400 MeV per nucleon. The deduced source radii are found to depend on the radial explosion energy used in the model. The inclusion of such collective expansion is necessary for a reasonable description of the experimental single-particle spectra of the IMFs. The unique Coulomb suppression of small relative IMF velocities, found for the given beam energy range, is attributed to rather constant averaged next-neighbour distances left angle d{sub IMF} right angle =8.6{+-}0.2 fm of the IMF charge centers within the source at break-up time. (orig.)}
place = {Germany}
year = {1994}
month = {Sep}
}