Abstract : During this thesis, a scanning ion beam monitor has been developed in order to measure on-line fluence spatial distributions. This monitor is composed of an ionization chamber, Hall Effect sensors and a scintillator. The ionization chamber set between the beam exit and the experiment measures the ion rate. The beam spot is localized thanks to the Hall Effect sensors set near the beam sweeping magnets. The scintillator is used with a photomultiplier tube to calibrate the ionization chamber and with an imaging device to calibrate the Hall Effect sensors.
This monitor was developed to control the beam lines of a radiobiology dedicated experimentation room at GANIL (Grand Accélérateur National d'Ions Lourds). These experiments are held in the context of the research in hadrontherapy. As a matter of fact, this new cancer treatment technique is based on ion irradiations and therefore demands accurate knowledge about the relation between the dose deposit in biological samples and the induced effects. To be effective, these studies require an on-line control of the fluence.
The monitor has been tested with different beams at GANIL. Fluence can be measured with a relative precision of ±4% for a dose rate ranging between 1mGy/s and 2Gy/s. Once permanently set on the beam lines dedicated to radiobiology at GANIL, this monitor will enable users to control the fluence spatial distribution for each irradiation.
The scintillator and the imaging device are also used to control the position, the spot shape and the energy of different beams such as those used for hadrontherapy.