Study of High-Energy Nuclear-Beam Transport

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Present status of the high-energy heavy-ion beam transport technology was investigated at various accelerator facilities in the world.Basic problems associated with the heavy-ion transport, i.e. (1) Relatively very low intensity compared with the proton beam ; (2) Immediate beam loss through the projectile fragmentation ; (3) Beam purity deterioration due to the fragmentation products of the same proton/neutron ratio as primaries ; were found to be the common problems there. Several very artificial beam profile/intensity/position monitors were developed for the heavy-ion transport at CERN,BNL,and GSI.These are all very keen beam detectors and can discriminate atomic numbers of the incoming high energy particle. We found also that beam monitors at low energy facilities can be applied for the high-energy heavy-ion beam. Beam monitors developed for electron beam were also interesting for the pulsed beam in near future. Drawings of these monitors were systematically collected and kept at t … More he beam channel group of the KEK-PS.The absolute calibration of the heavy-ion intensity is the one of the most important technology. At present no standard method is established. People at BNL and CERN employed the ion chamber and calibrated it by low intensity protons and extrapolated the beam-intensity/output-current relation to heavy ions using dE/dx-z^2 ; where z is the atomic number of the primary particle. The linear response of ion chamber for high-z primaries is tacitly assumed. It is, unfortunately, a fault. We then paid our attention to the target fragmentation process.The production cross sections of the target fragmentation are exceptionally well established even in the heavy-ion induced reactions. Then we can determine the primary heavy-ion intensity by measuring number of intermediate mass fragments (IMFs) with proper atomic number emitted in the target fragmentation. We employed the Bragg Curve Counter (BCC) as an IMF detector, which can determine the atomic number and energy of IMFs si, ultaneously. We constructed the prototype of the BCC and tested it in Japan. A part of this work has been published in several journal articles.During the investigation, we found that the heacy-ion beam transport technology is closely related with the physics program of the accelerator facility. We then partly extended our investigation to the physics program using heavy-ion beams. Results of this investigation is also accumulated at the beam channel group of the KEK. Less