Radiation transport effects in heavy‐ion beam–target interaction studies: Measurement of target opacity and beam conversion efficiency

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Abstract
In this paper detailed simulations are presented of radiation‐hydrodynamic response of gaseous cylindrical targets irradiated with heavy‐ion beams that will be produced at the Gesellschaft für Schwerionenforschung, Darmstadt, using a heavy‐ion synchrotron (SIS) [Heavy Ion Fusion, AIP Conference Proceedings No. 152 (AIP, New York, 1986), p. 23]. The purpose of this work is to explore material conditions for which the thermal radiation effects can be maximized. This is desirable in order to study a number of interesting and important effects including maximization of conversion efficiency of the ion beam energy to thermal radiation and measurement of the target opacity in the SIS experiments. It is expected that the SIS beams will produce a specific deposition power of 10 TW/g. The simulations in this paper show that a temperature of the order of 10 eV could be achieved by the SIS beams using homogeneous, cylindrical Xe targets. It has been shown that with the help of these computer simulations one should be able to measure the target opacity in these experiments within a factor of 3. Also these calculations show that in the SIS experiments one should be able to have a 50% conversion efficiency using a Xe target under optimum conditions. It has been found that the radiation effects will be optimized in the SIS experiments if the initial target density is of the order of 10−3 g/cm3. If the initial density is too high (of the order of 10−1 g/cm3 or more), hydrodynamic effects will dominate, while, on the other hand, if the initial density is too low (of the order of 10−4 g/cm3 or less), the electron thermal conductivity will take over.