Acceleration of Heavy Ions at the Bevatron

Abstract

Substantial beams of deuterons, alpha-particles, and nitrogen ions have been accelerated to high energies (nitrogen to 36 billion electron volts) in the bevatron. Beams of various energies were successfully extracted for experimental use. Modifications of the ion source, the injector, and the main acceleration system made the production of highenergy heavy ions possible. Our computer control system played an important part.

Projectile fragmentation reactions of40Ar at 57 MeV/nucleon

“…The experiments using primary beams of 40,48 Ca and 58,64 Ni at 140 MeV/nucleon on 9 Be and 181 Ta targets have showed that the cross sections are overestimated in EPAX2 calculations for the fragments far from the stability valley [18]. Similar results have been found in experiments of 86 Kr at 64 MeV/nucleon and 40 Ar at 90-94 MeV/nucleon on 9 Be and 181 Ta targets [19,20].…”

“…Since the pioneering work at Berkeley in 1970s [8,9], the reaction mechanism of projectile fragmentation (PF) has been studied extensively. For projectile-like fragments produced in the PF reactions at relativistic energies (>200 MeV/nucleon), the momentum distribution has been found to have a Gaussian shape [10] with its peak located around the velocity of the projectile [11] and whose width is well understood within the Goldhaber model [12].…”

“…The experiments using primary beams of 40,48 Ca and 58,64 Ni at 140 MeV/nucleon on 9 Be and 181 Ta targets have showed that the cross sections are overestimated in EPAX2 calculations for the fragments far from the stability valley [18]. Similar results have been found in experiments of 86 Kr at 64 MeV/nucleon and 40 Ar at 90-94 MeV/nucleon on 9 Be and 181 Ta targets [19,20]. In addition, experiments have also shown that the production cross sections of the isotopes far from the stability valley are enhanced in the reactions on 181 Ta target, which implies that the factorization hypothesis is invalid for * sunzhy@impcas.ac.cn very neutron-rich and very proton-rich isotopes, maybe due to the transfer reaction involved [20,21].…”

Heavy-Ion Radiobiology: Cellular Studies

“…Tobias et al (1971a) pointed out that accelerated heavy ions combine the good depth penetration properties of protons and pions with high RBE and low OER. Attention then turned to existing accelerators as possible sources of heavy ions, and in August 1971 two independent groups, one at Princeton (White et al, 1971) and the other at Berkeley (Grunder et al, 1971) accelerated nitrogen ions to several hundred MeV/u kinetic energies by introducing heavier gases into the injector designed for protons. Initial biological and physical results were reported by Tobias (1971), Todd et al (1971), and Schimmerling et al (1973Schimmerling et al ( , 1976Schimmerling et al ( , 1977.…”

“…With the growing expertise in accelerator design, it has become practical to investigate the radiobiological actions of these ions. The construction of synchrotrons at Princeton and Berkeley (Grunder et al, 1971;White et al, 1971;Isaila et al, 1972) first permitted examination of the biological effects of heavy ions with atomic numbers (z) between 6 and 18 at higher energies than were previously available (i.e., several hundred MeV/u). Although the initial heavy-ion energies at these machines were limited as to the production of beams with clinically significant ranges in tissue, biological studies indicated a likelihood of an enhanced therapeutic potential as compared to ion beams of lower atomic number (Tobias and Todd, 1967;Tobias, 1973).…”