New Beam Diagnostics at GANIL : Very Sensitive Current Transformers in Beam Lines and Counting System of Beam Turns in Cyclotrons

Two new beam diagnostics have been designed and are in operation at GANIL : - To measure very small beam currents without intercepting the beam, transformers have been developped whose resolution is as low as 1 enA. That is obtained by ussing synchronous detectors locked on the PIG source pulsation and by reducing the noise level. - As the accelerated orbits in the second main cyclotron are overlapping one another, we cannot count the number of turns by a classical moving probe. Therefore we compute the cross-correlation function of the beam signals detected on inductive probes at the input and the output of the cyclotron. Due to the natural random beam structure, this cross-correlation function has a sharp maximum for the value of the beam time of flight. Thence the right number of beam turns can be calculated.