• G. Balbinot, M. Caldara, L. Lanzavecchia, A. Parravicini, M. Pullia
  CNAO Foundation, Milan
• J. Bosser
  CERN, Geneva

The CNAO, the first Italian center for deep hadrontherapy, is presently in its final step of installation. Commissioning of the low energy injection lines has been successfully concluded in January 2009. The synchrotron injection chain consists of a 8 keV/u Low Energy Beam Transfer (LEBT) line, an RFQ to accelerate the beam up to 400 keV/u, a LINAC to reach the 7 Mev/u injection energy and a Medium Energy Beam Transfer line. At the end of the LEBT line, just upstream the RFQ, an electrostatic Chopper deviates the beam for about 100 micro-seconds every 2 seconds on the vacuum chamber, in order to shape the particles batch according to LINAC requirements and to minimize the beam lost at the RFQ entrance. The chamber section hit by the beam was electrically isolated from the adjacent vacuum chambers, allowing the reading of the LEBT beam current. The detector is based on the Faraday Cup working principle, but it results in a “not-interceptive” monitor that is able to measure, continuously, the source beam current ripples and stability without affecting the beam delivered to the synchrotron. The system is presently under commissioning with beam and preliminary results are presented.