• D. Alesini, A. Battisti, O. Coiro, T. Demma, S. Guiducci, V. Lollo, C. Milardi, P. Raimondi, M. Serio, R.S. Sorchetti, M. Zobov
  INFN/LNF, Frascati (Roma)

Metallic clearing electrodes have been designed to absorb the photo-electrons in the DAΦNE positron ring. They have been inserted in the wigglers and dipoles vacuum chambers and have been connected to external high voltage generators. In the paper we present the design of the devices and the results of the electromagnetic simulations related to both the transfer and longitudinal beam coupling impedances. We also present the results of the RF measurements and the first results with the DAΦNE circulating positron beam.

• G. Franzini, O. Coiro, D. Pellegrini, M. Serio, A. Stella
  INFN/LNF, Frascati (Roma)
• M. Pezzetta, M. Pullia
  CNAO Foundation, Milan

CNAO, the Italian Centre of Oncological Hadrontherapy located in Pavia, is under commissioning and will be soon fully operational. It is based on a synchrotron that can accelerate carbon ions up to 400 MeV/u and protons up to 250 MeV for the treatment of patients. In this paper we present the subsystem, called B-Train, which has the purpose of measuring the magnetic field in a dedicated dipole connected in series with the sixteen dipoles of the synchrotron and to provide instantaneous values of the synchrotron field to the dipole power supply, to the RF, diagnostics and dump bumpers control systems, via optical lines, using a custom communication protocol. In order to measure the magnetic field with the specified precision (0.1G over 1.5T @ 3 T/s), a different approach has been taken with respect to previous versions of the system. The field is obtained by digitizing the voltage induced on a pick-up coil inserted in the gap of the dedicated dipole through a 18 bit, 1.25 Msamples/s ADC and integrating it by numerical methods. This paper describes the final design and features of the B-Train system, as well as the results obtained on the magnetic field readings precision.