This paper represents the results of modeling the electrodynamic characteristics (EDC) for a quarter-wave coaxial beam buncher, simulation of thermal loads of the buncher, modeling of the mechanical changes in the geometric parameters caused by the thermal load of the buncher and modeling of the new EDC depended on this changes.
A new NICA heavy-ion collider is now under construction at JINR. At the same time, the Nuclotron facility is being modernized. A joint team from the JINR, MEPhI, and ITEP are now reconstructing a proton and light-ion injection system. New results of the RFQ linac resonator testing and measurements and RF power load are discussed in this article.
The NICA ion collider project at JINR is under development at present. As a part of the project the Nuclotron injector upgrade has been started. The work is provided in cooperation of JINR, MEPhI and ITEP. Up to now the Nuclotron injection system consist of a number of proton and ion sources, the 650 keV pulsed preinjector and DTL linac LU-20 (Alvarez type). Such system provides injection into Nuclotron of 20 MeV proton and 5 MeV/u (Z/A >0.3) ion beams. The ion beam acceleration is realized at the 2nd harmonic of bunch travelling mode. The 650 kV high-voltage platform will be replaced by new RFQ structure. The R&D of this system is discussed in the report. Results of beam dynamics simulation in RFQ and MEBT between RFQ and LU-20, electrodynamics simulation, construction of RFQ resonator, RF feeding system construction will be presented. The RF power system is assembled and tested at equivalent load and RFQ resonator manufacturing is started.
The 4 vane RFQ resonator with magnetic coupling windows as initial part of high-current Heavy Ion Linac for ITEP TWAC facility is presently under commissioning at ITEP. It was constructed for acceleration of ions with 1/3 charge to mass ratio to the energy of 1.57 MeV/u with beam current up to 100 mA. Additional beam dynamics simulations have been carried out for actual fields of the RFQ in order to determine both extreme output beam properties for different ion species with charge to mass ratio in the range of 1-0.25 and limitations for high-brightness of the high-current injector. The beam test of RFQ has been started with protons at relatively low electrode voltage for experimental studying the RFQ beam dynamics in the wide range of rf power operation. First results of the beam test in comparison with beam dynamics simulations are presented.
A joint research and development of steady state intense boron ion sources for 100's of electron-volt ion implanters has been in progress for the past five years. Current density limitation associated with extracting and transporting low energy ion beams result in lower beam currents that in turn adversely affects the process throughput. The transport channel with electrostatic lenses for decaborane (B10H14) and carborane (C2B10H12) ion beams transportation was developed and investigated. The significant increase of ion beam intensity at the beam transport channel output is demonstrated. The transport channel simulation, construction and experimental results of ion beam transportation are presented.
The joint research and development program is continued to develop steady-state ion source of decaborane beam for ion implantation industry. Both Freeman and Bernas ion sources for decaborane ion beam generation were investigated. Decaborane negative ion beam as well as positive ion beam were generated and delivered to the output of mass separator. Experimental results obtained in ITEP are presented.
A joint research and development effort focusing on the design of steady state, intense ion sources has been in progress for the past two and a half years with a couple of Russian institutions. The ultimate goal of the effort is to meet the two, energy extreme range needs of mega-electron-volt and 100's of electron-volt ion implanters. This endeavor has already resulted in record steady state output currents of higher charge state antimony and phosphorous ions to meet high-energy implantation requirements. For low energy ion implantation, R&D efforts have involved molecular ions and a novel plasmaless/gasless deceleration method. To date, 1 emA of positive decaborane ions were extracted at 10 keV and a smaller current of negative decaborane ions were also extracted. Though of scientific interest, negative decaborane ions did not attract interest from industry, since the semiconductor ion implant industry seems to have solved the wafer-charging problem. This paper describes conditions under which negative decaborane ions are formed and extracted from a Bernas ion source.
In the Linac4/SPL projects at CERN, 352 MHz DTL Alvarez accelerating structures will be used to accelerate protons between 3 and 40 MeV. The R&D for the development of a prototype structure for the energy range from 3 to 10 MeV is taking place jointly at ITEP and VNIIEF. The design of this 2.7 m Alvarez tank containing 27 drift tubes is described in this document. Results of calculations of the section parameters are presented. One of the main features of the design is the use of permanent magnets made of SmCo5 alloy as quadrupole focusing lenses (PMQ) inside the drift tubes. Details of the experimental PMQ-equipped drift tube are described.