| Paper | Title | Page |
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TUCA03 |
Beam Dynamics Optimization and RFQ Design | |
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Funding: This work was supported by St. Petersburg State University, project number 9.38.673.20 The problem of RFQ design is considered. Optimization approach to obtain desired output beam parameters is suggested. Acceleration of heavy ions (A/Z=20) is discussed. From start version up to the final one the BDO-RFQ and LIDOS RFQ associated codes are used. |
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| TUCA04 | Mechanism of Compression of Positron Clouds in the Surko Trap of the LEPTA Facility | 20 |
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| Results from experimental studies of plasma storage in the Surko trap at the LEPTA facility are presented. The number of stored particles is found to increase substantially when using the socalled "rotating wall" method, in which a transverse rotating electric field generated by a cylindrical segmented electrode cut into four pairs is applied to the positrons storage region. The conditions of transverse compression of the plasma bunch under the action of the rotating field and buffer gas are studied. The optimal storage parameters are determined for these experimental conditions. Mechanisms of the action of the rotating field and buffer gas on the process of positron clouds storage are presented. | ||
| TUPSA07 | Transit Code for Beam Dynamic Simulation | 51 |
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| Multiparticle computer code TRANSIT for simulation of intense ion beams in linacs and transport systems is presented. The code is based on experience in design of ion linacs in ITEP. TRANSIT summarizes the most actual and modern methods and algorithms for integration of motion equations including space charge forces. It is being used in ITEP for design and simulation of conventional RFQs, spatially periodic RF focusing linacs, beam transport systems, RF deflectors, etc. The paper presents general description of TRANSIT code and some achieved results. | ||
TUPSA08 |
Numerical Study of Beam Current Limit in the I-3 Ion Injector | |
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| The I-3 injector is used now for acceleration of A/Z=2-5 ions with maximal beam current of 5 mA up to energy of 4Z MeV. Possibility of increase for accelerated beam current is studied by beam dynamics simulation in the LEBT line and accelerating structure taking into account the realistic configuration of focusing and accelerating fields. Results of both beam dynamics and electrodynamics computer simulations for the I-3 accelerating structure that is 2.5 MHz two gap resonator are presented. | ||
| TUPSA09 | Beam Dynamics Calculations in the Multi-Beam Generator Cavity | 54 |
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| In the previously designed, calculated and tuned structure of the compact generator-cavity the beam dynamics for the different geometry options has been calculated. The influence of injected beam parameters to the output power value has been overviewed. Also the geometry of the beam tubes and couple coefficient between cavity and the output waveguide has been optimized to reach the maximum output power value. | ||
| TUPSA10 | Advanced Optimization of an Low-energy Ion Beam Dynamics at Linac Front-end with RF Focusing | 57 |
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| A design and development of a linac front-end, that guaranties the required beam, quality is an issue of the day. A linac with RF focusing by means of the accelerating field spatial harmonics is suggested as an alternative to RFQ system. Simulation results of the low-energy proton beam dynamics at linac, that takes into account main linac parameter optimization, based on advanced dynamical acceptance calculation, are presented and discussed. | ||
TUPSA11 |
Longitudinal Dynamics of a Bunch of Charged Particles in a Traveling Wave Field | |
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| The longitudinal dynamics of a bunch of charged particles in a traveling wave field has been studied. A Lagrange function for this motion is constructed and the Lagrange equation describing longitudinal envelopes of the bunch is derived. The obtained equation describes longitudinal envelopes of a bunch of charged particles. It is advantageous to the well-known equations of envelopes, primarily, in being simple. Additional advantages are as follows. First, the solutions of equation determine not only the longitudinal size of a bunch, but also the width of its energy spectrum. Second, the equation has been derived without any restrictions imposed on the bunch length (phase space dimension), so that the model is nonlinear and, hence, more general. Third, the equation takes into account the acceleration of a bunch. Finally, Lagrange equation takes into account the force of the intrinsic Coulomb field of a bunch in terms of the naturally included ellipsoid model, so that this envelope equation is self-consistent. | ||
| TUPSA12 | The User Friendly Interface for BEAMDULAC-RFQ Code | 60 |
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The BEAMDULAC* beam dynamics simulation code is under development at MEPhI Department of Electrophysical Facilities since 1999. Such code includes versions for beam dynamics simulation in a number of accelerating structures as RFQ, DTL, APF, transport channels, ets. The motion equation for each particle is solved selfconsistently in the external fields and the inter-particle Coulomb field simultaneously. The BEAMDULAC code utilizes the cloud-in-cell (CIC) method for accurate treatment of the space charge effects. The external field can be represented analytically, as a series or on the grid. The absence of user friendly interface was the main disadvantage of the code. Last year such interface was developed and will present in the report.
* S.M. Polozov. Problems of Atomic Science and Technology. Series: Nuclear Physics Investigations, 3 (79), 2012, p. 131-136. |
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| TUPSA13 | The Interactive Computer Environment for Designing and Tuning of Charged Particle Beams Transport Channels | 63 |
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| This paper considers the application package that simulates transport channel of relativistic charged particles. The package provides an interactive mode for the user. It is possible to observe the main parameters of the beam crossing the channel on the PC screen such as envelope and cross-section of the beam at different sections of the channel while changing the main control parameters of the real channel. Enabling of procedures of mathematical programming provides express optimization of control parameters of the channel. The designed package is compact, has a modular structure and can be easily adapted to different software platforms. MATLAB integrated environment is used as instrumental environment, which has a freeware version of this system - SCILAB. Package testing was carried out on the electron synchrotron "Pakhra" during the recalibration of the channel of the accelerator working in different modes, which are determined by conducted experiments. | ||
| TUPSA14 | Mathematical Optimization Model of Longitudinal Beam Dynamics in Klystron-Type Buncher | 66 |
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| The paper presents recurrent integral-differential beam evolution model. This model is convenient for mathematical description of specific dynamic processes with due account of particle interaction and electric fields excitation by moving beam. On the basis of this model the problem of beam dynamics optimization is formalized as trajectory ensemble control problem. Analytical expression for quality functional gradient is obtained. Theoretical results are applied for solving problem of beam dynamics optimization in klystron-type buncher. | ||
| TUPSA15 | Second Order Method for Beam Dynamics Optimization | 69 |
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Funding: This work is supported by St.-Petersburg State University grant #9.38.673.2013. Methods of beam dynamics optimization of the first order are known and used for beam dynamics optimization*. These method are based on numerical calculation of gradient of functional estimating beam quality. In this report, method of optimization is proposed that includes numerical calculation of the second derivations (Hessian) of the quality functional. Proposed method is applied for a beam in RFQ channel. Control problem is formulated. The propblem consists in minimizing of functional depending on the beam density and on control functions. The control functions are the acceleration efficiency, the synchronous phase, and the channel apperture. For numerical solution the control functions are taken in parameterized form. The process of optimization represents a sequence of steps with use of the first and the second derivatives on parameters, during which the value of the functional decreases. * D.A. Ovsyannikov, O.I. Drivotin. Modeling of Intensive Charge Particle Beams. St.-Petersburg: Publ. Comp. of St.-Petersburg State Univ., 2003. |
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| TUPSA16 | Electron Gun with Adiabatic Plasma Lens | 72 |
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Funding: This work supported by the Russian Foundation for Basic Research (grant № 12-02-00866-а) For researches on plasma physics has been designed and constructed the electronic gun with the cold cathode on energy about 250 keV. The electron beam have the parameters: time width of pulses 100 ns, current amplitude 100 A. The adiabatic plasma lens is used to reduce the beam size to the demanded value. The results of tests are presented. |
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| TUPSA17 | Axial Injection to a Compact Cyclotron with High Magnetic Field | 75 |
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| One of advantages of a compact cyclotron over other type accelerators is a small size mainly defined by the facility’s bending magnetic field. In such cyclotrons an application of an external injection is required in some cases. But for high magnetic field of the cyclotrons (over 4-5 T) there appears a severe problem to make the 1st turns in the machine with external injection of accelerated particles. This paper describes a proposal of a new central region structure of a compact cyclotron that permits one to successfully solve the problem of the axial injection into such a facility using a spiral inflector. | ||
| TUPSA18 | Complex Shunt Impedance and Beam-RF Cavity Interaction | 77 |
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| Two approaches usually are used to describe beam-cavity interaction in accelerator based applications. The first one is electro dynamical and uses Maxwell equations to derive appropriate equations, field modes expressions being necessary to calculate field amplitudes excited by moving charges in the cavity. The other one uses LC circuit to derive appropriate equations for voltage amplitude induced in cavity by accelerated bunches, thin accelerating gap to some extent being not fully correctly defined representation in such approach. In this paper, the expressions are derived that describe beam-RF cavity interactions in terms of so called complex shunt impedance, strict electro dynamical approach being used in calculations. It is shown that complex shunt impedance module coincides completely with usual shunt impedance definition that up to now is used widely to describe rf cavity efficiency. The physical sense of its phase is given in the paper as well. Both complex shunt impedance module and its phase can be calculated or measured experimentally. | ||
TUPSA19 |
Low Energy Electron Beam Line at Lebedev Physical Institute Accelerator Complex | |
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| Microtron with the energy 7 MeV and beam current up to 30 mA is used as injector to electron synchrotron since 1974-th year. Several last years it is used to supply with electron beam the nuclear physics experiments as well. New experiments in the field of solid state physics are planed. Although there are two experimental halls at the accelerator complex environment experiments for the cost considerations where carried near to microtron, and this results in enhanced background. To make it possible to carry out several experiments at the same time in more comfortable conditions with minimum background the beam line from microtron to experimental hall with several end stations is under development. Followed are this beam line design features. | ||
| TUPSA20 | Output Energy Variation in the SC Linac for the Proton Radiotherapy | 80 |
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Current success of the superconducting linear accelerators based on independently phased SC cavities gives a seriously reason to consider such structure in proton radiotherapy. Superconductivity allow to solve at once some problems concerned with a low rate of energy gain, high length, higher capacity losses and higher cost of the proton linear accelerator subsequently. One of the traditional aims of such facilities is receiving of the beam energy about 240 MeV with possibility of fluently regulation in range from 150 to 240 MeV that responds to irradiate the tumors located at different depth. The possibility of beam energy variation by means of RF field phase in last resonators and number of the resonator turn-off becomes the major advantage of the proton SC linac. The optimal choice of accelerator parameters and the beam dynamics simulation results with using BEAMDULAC-SCL code will presented*. Methods of the output energy variation with beam quality preservation in the proton SC linac will discussed.
* A.V. Samoshin. Proc. of LINAC2012, Tel-Aviv, Israel, TUPB069, p. 630 - 632 |
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TUPSA21 |
Beam Formation for Different Energies on the Target of INR Isotope Complex with the Transverse Phase Space Parameters Demanded | |
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| The main problem was to get the same transverse phase space parameters on the isotope target for the different proton beam energies within a large deviation range. Two matching parts placed on the linear accelerator structure were used. The data of the transverse phase space parameters depending on the focusing structure of the isotope complex transport line were calculated at the point before the dipole of isotope line rejection. The beam dynamics restrictions were used for simulations. The crossing of the transverse phase spaces for different beam energies permits to get the reliable solutions for transverse beam dynamics with the identical supply currents, which are used for the transverse focusing on the linear accelerator structure both for simulations and experiments. | ||
TUPSA22 |
Design of 14 MeV APF Linac | |
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| A approach based on combination of gradient optimization methods and genetic algorithm to obtain the parameters of APF linac is suggested. As an example, the parameters of 14 MeV 10 mA deuteron linac are presented. | ||
| TUPSA23 | LEPTA - the Facility for Fundamental and Applied Research | 83 |
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| Storage ring of LEPTA facility was commissioned in September 2004 and was under development up to now. The positron injector has been constructed in 2005-2010, and beam transfer channel – in 2011. By the end of August 2011 experiments on electron and positron injection into the ring have been started. The last results are presented in this report: studies of e+/e− dynamics in trap, e+ beam in the ring, LEPTA upgrade (vacuum, e+ source with cryocooler), Channel for PAS. | ||