MODERNIZAION OF THE U400 CYCLOTRON AT THE FLNR JINR

The U400 cyclotron diameter is 4 m, the K-factor is 625. The U400 has been put in operation since 1978. The stripping foil method is used to extract ion beams. The axial injection system with the ECR ion source and two bunchers (Sine and Line types) was created in the period of 1996-1998. At present time, some cyclotron parameters can be improved. First of all it is concern of the total acceleration efficiency and possibility to vary ion energy fluently at factor 5 for every mass to charge ratio A/Z by means of changing the RF frequency and the magnetic field. The width of ion energy region will be from 0.8 to 27 MeV/nucleon. The project of U400 modernization intends decreasing the magnetic field level at the cyclotron center from 1.93÷2.1Т to 0.8÷1.8Т. One intends changing the construction of the axial injection. For ion extraction out of the U400, both the stripping foil and deflector methods are considered. Also, the project intends changing the U400 vacuum, RF and power supply systems.