Realization of acceleration of laser-injector-generated carbon nuclei in the synchrophasotron at the Joint Institute for Nuclear Research

Abstract

Radiographic or silver halide film is a well-established 2D dosimeter with an unquestioned spatial resolution. But its higher sensitivity to low-energy photons has to be taken into consideration. Metal compensators or physical modulators to deliver intensity modulated radiation therapy (IMRT) are known to change the beam energy spectrum and to produce scattered photons and contaminating electrons. Therefore the reliability of film dosimetry in compensator-based IMRT might be questioned. Conflicting data have been reported in the literature. This uncertainty about the validity of film dosimetry in compensator-based IMRT triggered us to conduct this study. First, the effect of MCP-96 compensators of varying thickness on the depth dose characteristics was investigated using a diamond detector which has a uniform energy response. A beam hardening effect was observed at 6 MV that resulted in a depth dose increase that remained below 2% at 20 cm depth. At 25 MV, in contrast, beam softening produced a dose decrease of up to 5% at the same depth. Second, dose was measured at depth using EDR2 film in perpendicular orientation to both 6 MV and 25 MV beams for different compensator thicknesses. A film dose underresponse of 1.1% was found for a 30 mm thick block in a 25 MV beam, which realized a transmission factor of 0.243. The effect induced by the compensators is higher than the experimental error but still within the accepted overall uncertainty of film dosimetry in clinical IMRT QA. With radiographic film as an affordable QA tool, the physical compensator remains a low threshold technique to deliver IMRT.

Direct injection of fully stripped carbon ions into a fast-cycling induction synchrotron and their capture by the barrier bucket

“…Anani'n and colleagues demonstrated the acceleration of carbon ions formed by an LAIS in the Synchrophasotron at the Joint Institute for Nuclear Research, Dubna, Russia [6]. Carbon ions are accelerated in a preinjector and LU-20 linear accelerator, which provide an energy of 5 MeV=u.…”

Laser produced plasma as an ion source for heavy ion inertial fusion

“…The advantage of laser produced plasma as a source of multicharged ions (MCI) for an accelerator has been confirmed both by physical research (Bykovskii et al 1979) and by direct experiments of MCI acceleration in a synchrophasotron LHE (Ananin et al 1977) and a cyclotron LNR at the Joint Institute of Nuclear Research in Dubna (Ananin et al 1982). For related work, see Peacock et al (1969) Tonon (1972) and, for very energetic ions, Hora et al (1978);, which predicted the 100 MeV ions measured by Sessler (1982).…”