Kurakin, V.G.
|
ECOLOGICALLY CLEAN ACCELERATOR FOR NUCLEAR PHYSICS RESEARCH |
|
|
V.G. Kurakinª, A.V. Koltsov Lebedev Physical Institute of Russian Academy of Sciences, Moscow, Russia Abstract Rigid ecological requirements to human activity including industry and science force to search for specific technologies to reduce the undesired influence on nature. High intensity accelerators belong to the objects that produce radioactive waste. We have studied rf accelerator schema where the electron beam used is directed again into the same accelerator with appropriate phase in order to reduce beam energy down to acceptable level and in such a way to reduce radioactive problem for environment (beam energy recovering). In addition, this reduces background at experimental area as well as saves rf power in the case of superconducting rf cavities. The following main processes have been taken into account while considering beam emittance degradation in a target: multiple electron scattering, ionization losses and bremsstrahlung. The first one results in transverse beam emittance growth while the latter two result in beam energy losses and energy spectrum width growth as well. Appropriate calculations have bean made and various plots have been presented. Critical target parameters namely target material nuclei charge as well as target thickness that allows leave a possibility the recovering process can be defines from these plots. ª – corresponding author |
|
|
EXTERNAL PARAMETERS CALCULATIONS FOR RF RESONATOR EXCITED OVER AN APERTURE |
|
|
V.G. Kurakinª Lebedev Physical Institute of Russian Academy of Sciences, Moscow, Russia Abstract Bubnov and Galerkin method is used to calculate the coupling strength and cavity detuning for an rf cavity being powered by rf waveguide over a rectangular aperture in cavity surface. Both these so call external parameters are of a value in order to develop properly accelerating system of an accelerator. Electrical fields on coupling aperture surfaces are approximated by finite sums coordinate functions and expansion coefficients are found out by appropriate procedure of solution join of neighboring regions. In Bubnov and Galerkin method, this procedure provides energy flow continuity while crossing coupling surfaces, and this provides fast convergence of appropriate infinite sums. Expressions for aperture conductances are derived followed by formulae for reflection coefficient and cavity detuning. ª – corresponding author |
|
|
SUPERCONDUCTING RF ELECTRON RECIRCULATOR FOR NUCLEAR PHYSICS RESEARCH AT LEBEDEV PHYSICAL INSTITUTE |
|
|
V.G. Kurakinª¹, G.A. Sokol¹, V.G. Nedoresov², B.S. Ishkhanov³, V.I. Shvedunov³ ¹Lebedev Physical Institute of Russian Academy of Sciences, Moscow, Russia ²Institute for Nuclear Research of Russian Academy of Sciences, Moscow, Russia ³Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia Abstract Conceptual design of the superconducting rf accelerator is discussed. This machine is supposed to be used in the field of low and intermediate energy nuclear physics. Four pairs of dipole magnets at the vertexes of square and four superconducting rf linacs between them form a configuration that allows multiple electron beam acceleration from the injection to the final energy, synchronism being provided by proper orbit lengthening in bending magnets after each turn. Additional superconducting rf linac is used for injection into the main accelerator. Special design of dipole magnet makes it possible to stop recirculation in order to guide beam to experimental area. Thin target is used for experiments in order to recover beam energy. This allows to save rf energy and to provide safe radiation conditions of the accelerator as well. Synchronism conditions as well as dipole magnet design dictate the energy gain per turn in the accelerator. For field strength about 14 kGs in dipoles the energy gain per turn is 600 MeV for TESLA type superconducting cavity (f=1.3 GHz), and the maximum electron energy 2 GeV might be realized with 3 turns. Taking into account the working accelerator gradient 25 MeV/m of TESLA type cavity the accelerator might be placed in existing accelerator hole of the high energy physics department in Troitsk where electron synchrotron to the energy 1.3 GeV is under operation now. The main arguments in favor of accelerator schema suggested are given in the paper. Beam optics as well as recovery problems are discussed followed the appropriate beam envelope calculations. ª – corresponding author |
|