Do we really understand nuclear reactions within thick targets using GeV-hadrons?

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

“…The ®theoretical¯value for R 0 ( 24 Na) at 72 GeV is also included as described in Sec. 2 [1,2]. The value R exp 0 ( 24 Na) at 0.6 GeV agrees with model calculations [1] and the line labelled ®theoretical¯between these two points is drawn to guide the eye.…”

“…In this case, the model calculation describes the enhancement of the 24 Na production in dowstream Cu disks within theˇrst 8 cm correctly, followed by the expected decrease even further downstream. This ®enhancement factor¯of 32 for a speciˇc projectile fragment A p can be compared with a similar ®enhancement factor¯of 3.4 for all secondary products (1 A p 65), including protons and neutrons, as employed in a related analysis [1]. Again, the ad hoc assumption is based on the ®anomalon hypothesis¯mentioned already.…”

“…8. The experimental mass yield curves in theˇrst Cu disk assumed to be induced by primary 72 GeV 40 Ar ions [1,22] only and in the second Cu disk induced by the same primary beam plus secondary fragments produced in theˇrst Cu disk. Both Cu disks have been in contact.…”

“…It has been calculated that only 20% of all Ar ions interact within thě rst Cu disk and their kinetic energy is reduced only marginally [1]. Lerman could show, that nearly all Ar ions after theˇrst interaction move on as projectile-like ions.…”

“…The thickness of such a target could be 2 cm or more, ranging up to the total path of the primary ion within the target material. The problems to be discussed have recently attracted some fresh interest due to serious doubts about our complete understanding of nuclear interactions in thick targets [1]. The essential question is:…”