BEAM HEATING AND COOLING OF THICK TARGETS FOR ONLINE PRODUCTION OF EXOTIC NUCLEI

Calculations have been made of energy deposition distributions for "thick" targets (approximately 1 mole/cm2) employed in on-line production of exotic nuclei using the Monte Carlo based LAHET code system for high-energy charged particle transport. A variety of target materials and incident proton beam energies have been examined. For 600 MeV protons, the results are compared to those from a similar study reported in the literature. The agreement between the two studies for total energy deposition is reasonably good for monatomic targets, but the results differ in some details of the energy deposition distributions. Target cooling, both radiative and conductive, is examined to assess the suitability of existing target concepts exposed to bombardment by intense (up to 100-mu-A), energetic (500 MeV to 1.2 GeV) proton beams to produce exotic nuclei. Implications of cooling requirements to target material selection and design are discussed.