Unusual behavior of projectile fragments produced by the interactions of relativistic Ar ions with copper

Interactions of relativistic heavy ions in thick heavy element targets and some unresolved problems

“…Further details are given in Refs. [20,21] second disk, whereas the increase is only a factor of (1.35 ± 0.15) for masses 24 and 59. These results qualitatively conˇrm observations were presented in Fig.…”

“…6) surrounding the downstream Cu disk at d = 20 cm [21]. Quantitative results will be shown in Table 4 later.…”

“…The mass yield curve in theˇrst Cu disk produced in this irradiation is unknown at present. In our experiments only the ratios for R 0 ( A Z) were experimentally determined [20,21]. However, one can assume that due to the concept of ®limiting fragmentation¯the experimental mass yield curve for a thin Cu target produced by 1 GeV 12 C is approximately the same for 72 GeV 40 Ar interactions in theˇrst Cu disk.…”

“…A detailed analysis shows two further distinct differences. The B(A) values for masses 43 and 52 are larger by a factor of (2.2 ± 0.3) in the [20,21]. a) Schematic representation of the target set-up using two Cu disks and a surrounding guard ring around the second disk.…”

“…For A = 7 ( 7 Be) one measures R 0 ( 7 Be) = (1.28 ± 0.02), then R 0 ( A Z) increases to about mass A = 50 with a maximum around R 0 ( 51 Cr) = (2.35 ± 0.04) and then it decreases again towards higher masses up to mass 59 with R 0 ( 59 Fe) = (1.79 ± 0.03). The original papers on this subject [20,21] were concentrated almost exclusively on the interpretation of the experimental value for R exp 0 ( 24 Na) = (1.50 ± 0.02). This value was experimentally determined with high accuracy and the excitation function for the production of 24 Na from thin Cu targets is very well known for protons in the energy range 300 MeV < E p < 300 GeV and also for many other heavyion induced reactions.…”