Direct-reaction contributions to projectile-fragment spectra at 10?20 MeV/nucleon

McVoy, K.W.; Nemes, M. C.

doi:10.1007/bf01413075

Cited by 59 publications

(15 citation statements)

References 11 publications

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“…Figure 12 On the other hand, a linear dependance of ~0 with energy is observed for the transfer products (those with ZF> Zproj-3) with quite lower widths as compared to the fragmentation channel even at energies as high as 44 MeV/u. As already pointed out by Mc Voy and Nemes [33], it is not surprising to get such large differences for the two processes. For a transfer reaction, the particle is transferred on a definite final state due to momentum conservations and it puts strong constraints, which do not exist in break-up reactions, on the available phase space.…”

Section: V1 Fragmentation and Transfermentioning

confidence: 76%

Projectile like fragment production in Ar induced reactions around the Fermi energy

Borrel

Gatty

Guerreau

et al. 1986

Z. Physik A - Atomic Nuclei

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The production of projectile-like fragments (PLF) has been studied in Ar induced reactions on various targets. It shows very clearly, that besides the predominance of fragmentation for most of the products, the transfer process is still a very strong component for products nearby the projectile. The influence of the target neutron excess on the PLF production is investigated as well as the evolution with incident energy of the characteristics of the different competing processes.

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Section: V1 Fragmentation and Transfermentioning

confidence: 76%

Projectile like fragment production in Ar induced reactions around the Fermi energy

Borrel

Gatty

Guerreau

et al. 1986

Z. Physik A - Atomic Nuclei

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“…However, the observed value is quite consistent with experimental systematics (see [-6]). According to McVoy and Nemes [20] this finding indicates a break-up proceeding via transfer rather than by a fast abrasion. It has been pointed out [11] that a cutoff of the wave function at small distances due to the nuclear absorption effectively reduces the width go, since only the nuclear periphery is probed.…”

Section: Analysis Of Inclusive 6li Break-up Datamentioning

confidence: 82%

Orbital dispersion and wavefunction mapping in inclusive break-up experiments

Srivastava

Basu

Rebel

et al. 1990

Z. Physik A - Atomic Nuclei

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Inclusive break-up cross sections of the reactions 12C (6Li, a)X and 2~ (6Li, a)X at 26 MeV/amu, observed for the emission of break-up fragment into the forward hemisphere, are analysed in view of the information about the internal momentum distribution of the projectile. The longitudinal momentum distribution of the fragments in the projectile rest-frame is found to reflect the internal momentum distribution of the clusters whereas the transverse distribution is affected by the projectile-target interaction.

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“…The same representation for all measured 24-27Mg isotopes for example shows a flat ~r 0 distribution close to 109 MeV/c at 3~ the % value increases slowly as one moves to backward angles. The strong change for a 0 values observed here for S isotopes can be regarded as an illustration of the direct reaction contribution to projectile fragmentation calculated by McVoy and Nemes [14]. They predict widths 50 ~o larger for fragmentation than for the direct process.…”

Section: )mentioning

confidence: 83%

Few nucleon transfer versus fragmentation in the production of projectile-like fragments in the40Ar+68Zn reaction at 27.6 MeV/nucleon

Rami¹,

Coffin²,

Guillaume³

et al. 1984

Z Physik A

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The isotope distributions, momentum width distributions, and velocities of the projectile-like fragments in the S~ on 6SEn reaction have been measured at 27.6 MeV/nucleon incident energy. The results show the existence of a fragmentation process well described in the framework of the high energy fragmentation model. However, important contributions from direct nucleon transfer and damped collisions are present.Heavy ion reaction mechanisms evolve drastically when the projectile energy is varied from a few MeV per nucleon to hundreds of MeV per nucleon. Below 10 MeV/nucleon, there exist two classes of reaction process [1]: peripherical reactions corresponding to transfers of a small number of nucleons and central reactions leading to a complete damping of the relative motion of the colliding partners. At energies higher than 80MeV/nucleon the individual nucleonic collisions govern the reaction and the collisions can be described in terms of fragmentation [2][3][4]. A strong interest in the intermediate energy region (10-80 MeV/nucleon) where the transition occurs from typically low energy mechanisms to the high energy one has rapidly developed. In a recent experiment on the S~ (44 MeV/nucleon) on 58Ni and Au, Guerreau et al. [-5] and Borrel et al. [6] have shown that an important part of the projectile-like fragments exhibits the features of high energy fragmentation, even though quasi-elastic transfer of nucleons and collective interactions are still present. On the other hand, Egelhaaf et al. [-7, 8] have concluded from the study of ZONe on 197Au at up to 20MeV/nucleon that there is no rapid onset of fragmentation nor production of abnormally hot nuclear matter. A similar conclusion was reached by Menchaca-Rocha et al. [9] from the study of the bombardment of lzc, SSNi and 197Au by 30MeV/nucleon 12C: The projectile-like fragments observed result from quasi-elastic transfer re-* Experiment performed at GANIL, Caen, France actions and damped collisions. Thus, the expected transition between low and high energy reaction mechanisms should occur within 20 to 40 MeV/nucleon incident energy range. In this contribution we report on the 4~ reaction performed at GANIL using a 27.6 MeV/nucleon 4~beam in order to examine in detail the competition between few nucleon transfer reactions and the fragmentation process. We used rolled self-supporting ~ metallic targets. Some exposures using a Au target were also performed. The mass A and atomic number Z of the outgoing fragments were measured by means of a time-of-flight (TOF) spectrometer and solid state telescope detectors. From Fig. 1 showing a bidimensional spectrum (A, E) recorded at 01ab -~--5 ~ i.e. beyond the grazing angle 0gr=4 ~ several remarks can be made. I)Much of the yield is due to fragments lighter than the projectile, each having a relatively narrow energy distribution (~150MeV) whose centroid is such that the corresponding fragment velocity is close to that of the projectile (dotted curve). This suggests the presence of a projectile fragmentation mechanis...

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Direct-reaction contributions to projectile-fragment spectra at 10?20 MeV/nucleon

Cited by 59 publications

References 11 publications

Projectile like fragment production in Ar induced reactions around the Fermi energy

Projectile like fragment production in Ar induced reactions around the Fermi energy

Orbital dispersion and wavefunction mapping in inclusive break-up experiments

Few nucleon transfer versus fragmentation in the production of projectile-like fragments in the40Ar+68Zn reaction at 27.6 MeV/nucleon

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