Nikolay Kazarinov

Nonlinear distortion of multicomponent heavy ion beam emittance caused by space charge fields

The beam of 48Ca ions is obtained in an electron cyclotron resonance (ECR)-ion source with helium as plasma supporting gas. The current of helium ions is often greater than the calcium one. The influence of the helium ions self-fields on emittance of calcium beam during the common transportation from the ECR-ion source to analyzing bending magnet is investigated by macroparticles simulation. For a large magnitude of helium space charge, the calcium ions have a holed-beam shape after analyzing magnet and beam emittance strongly increased. The possibilities of elimination of this effect are discussed.

Injection and Acceleration of Intense Heavy Ion Beams in JINR New Cyclotron DC280

At the present time the activities on creation of the new heavy-ion isochronous cyclotron DC280 are carried out at Joint Institute for Nuclear Research. The isochronous cyclotron DC-280 will produce accelerated beam of ions with A/Z= 4 7 to energy W= 4 – 8 MeV/n and intensity up to 10 pμA (for 48Ca). The goal for DC-280 accelerator complex is more then 40 % beam transfer efficiency. To achieve high-intensity ion beam, the cyclotron is equipped with high-voltage, up to 80 kV, injection line and independent Flat-Top RF system. To decrease the aperture losses at centre region the electrostatic quadruple lens will be installed between inflector and first accelerating gap. The paper presents the results of simulation of beam injection and acceleration. INTRODUCTION One of the basic scientific programs which are carried out in the FLNR JINR is synthesis of new elements which requires intensive beams of heavy ions. At present time the isochronous cyclotron U-400, which is in operation since 1978, is capable of providing long term experiments on 48Са beams with an intensity of 1 pμA. Its operation time is more than 6000 hours per year. To enhance the efficiency of experiments it is necessary to obtain accelerated ion beams with the following parameters: Ion energy 4÷8 MeV/n Ion masses 10÷238 Beam intensity (up to A=50) 10 pμA Beam emittance less 30 π mm mrad These parameters formed the base for the new isochronous cyclotron DC-280 [1]. The basic technical solutions to realize new project are shown in Table 1. Table 1: DC-280 Cyclotron Basic Technical Solutions Parameter DC280 Goals 1. High injecting beam energy (up to 100 keV/Z) Decreasing space charge factor. Decreasing beam emittance. 2. High gap in the centre Space for a long spiral inflector 3. Low magnetic field Large starting radius. Good orbit separation. Low deflector voltage 4. High acceleration rate Good orbit separation. 5. Flat-top system High capture. Beam quality. The new cyclotron complex provides an opportunity of carrying out physical and chemical research using radioactive targets, such as U, Pu, Am, Cm, Bk. The layout of the cyclotron assembling is shown in Figure 1. Figure 1: The layout of the DC-280 cyclotron. Now the most of new cyclotron complex elements have been manufactured and the project is at the stage of laboratory building construction. THE AXIAL INJECTION SYSTEM The DC-280 injection system has to provide ion transition from the ECR-ion source to the cyclotron centre and capturing into acceleration more than 70 % of ions with the atomic mass to charge ratio of A/Z=48 [2]. The experience in operation of FLNR cyclotrons demonstrates that at ion energies of 15 keV/Z the injection efficiency essentially depends on the ion beam current. At the ion beam currents of 80÷150 eμA the efficiency of capture into acceleration reaches 30÷35 %, but for the ion currents less than 10 eμA increasing of the efficiency to 50÷60 % has been observed. The reason of it may be the decreasing of the ion beam space charge effect and decreasing the beam emittance, especially at low level of the microwave power in the ECR source. To improve the injection efficiency we will increase the injection energy up to 100 keV/Z, since the emittance and the space charge effects have to be decreased. The high-voltage axial injection of the DC-280 will consist of two high voltage platforms, HVP. The maximal voltage on the HVP will be 75 kV. Every HVP will be equipped with an ECR ion source with injection voltage 25 kV, a focusing elements and a magnet for ion separation and analyzing. The high voltage accelerating tube will be installed at the edge of the HVP to increase the ion energy. Two types of ECR ion sources will be used: the DECRIS-PM source with permanent magnets and the DECRIS-SC superconducting one. The first ECR ion source has to produce high intensities (15÷20 pμА) of ions with medium masses (for example, 48Са7+,8+), the MOA2C02 Proceedings of HIAT2015, Yokohama, Japan ISBN 978-3-95450-131-1 30 C op yr ig ht

Electrostatic Deflector of the Cyclotron DC-280 Axial Injection Channel

Abstract The spherical electrostatic deflector will be used in the axial injection channel of the DC-280 cyclotron for rotation of the ion beam onto vertical axis. The results of the simulation of beam dynamics in the deflector based on 3D electrical field map are discussed in this report. The results of simulation of the ion beam transport in the axial injection beam line of the cyclotron are presented also.

Magnets of Super Heavy Elements Facility

The design of two magnets of Super Heavy Elements Facility is presented. The magnets are the parts of injection and extraction systems of DC-280 cyclotron. The design is based on three-dimensional calculation of the magnet field carried out by using OPERA 3D program code.

Ohmic heated sheet for the Ca ion beam production.

The production of intense accelerated (48)Ca ion beams is the key problem in the experiments on the synthesis of new superheavy nuclei. For this purpose in the FLNR (JINR), an electron cyclotron resonance ion source is used at the U-400 cyclotron. The combination of a micro oven with a hot tantalum sheet inside the discharge chamber allowed the production of the intense (48)Ca(5+) ion beam at the (48)Ca consumption of about 0.5 mg/h. In this case, the tantalum sheet is heated by microwaves and plasma electrons. The microwave power of up to 500 W is required to heat the sheet to the temperature of about 500 degrees C. To decrease the required microwave power, a new sheet with a direct Ohmic heating was designed. The present paper describes the method, technique, and preliminary experimental results on the production of the Ca ion beam.