Radiation Dosimeter System for a 20 MeV Pulsed Linear Accelerator Beam at High Dose Rates for Radiobiological Applications
M.A. Mestari; J. Case; T. Webb; L.C. DeVeaux; and D.P. Wells (Idaho State University)
The next generation of radiobiology research will require increasingly exotic and complex radiation sources to address questions ranging from the effects of space-based radiation to the influence of large variations in dose rate upon a variety of radiation effects. The Idaho Accelerator Center (IAC) of Idaho State University (ISU) has developed a unique radiobiology radiation research facility to answer some of these next-generation kinds of questions. The IAC has 9 operating research accelerators. These include pulsed and continuously-delivered radiation beams such as a 1.2 MeV electron beam and a 2 MeV light-ion Van de Graaff. The fraction of the time that the beam is "on" with these latter accelerators, called the duty-factor, is unity. On the low duty-factor end of the spectrum, the IAC also has a number of pulsed electron linacs. These range in energy from 4 to 40 MeV and the most intense amongst them deliver peak dose rates greater than 1013 Gy/sec. The pulsed nature of these devices poses unique challenges for common dosimetry schemes because the attainable dose rate from pulsed electron linacs spans many orders of magnitude. We have developed a coupled Faraday-cup and PIN-diode system that allows real-time dosimetry in these extreme radiation fields. In addition we calibrate and compare these measurements to radiochromic film and calibrated TLD systems for quality control.