RUPAC2012 - List of Keywords (linac)

Paper	Title	Other Keywords	Page
MOACH02	Design and Simulation of Practical Alternating-Phase-Focused (APF) Linacs – Synthesis and Extension in Tribute to Pioneering Russian APF Research	focusing, acceleration, emittance, ion	12
	R.A. Jameson IAP, Frankfurt am Main, Germany
	Conventional magnetic transverse focusing in conventional linacs represents a high fraction of their cost and complexity. Both transverse and longitudinal focusing can be obtained from the rf field by using the strong-focusing effect of alternating patterns (sequences) of gap phases and amplitudes – known as Alternating-Phase-Focusing (APF). Although studied for decades, the difficulty of designing suitable sequences has inhibited APF adoption, although short sequence APFs are now used in a number of practical applications. Synthesis of reported details and new physics and technique result in a new, general and efficient method for designing APF linacs. Very long sequences with high energy gain factors are demonstrated, e.g. for acceleration of very cold muons from ~0.340-200MeV (factor 600).
	Slides MOACH02 [0.616 MB]

WEYCH02	Multipurpose Research Complex Based on the INR High Intensity Proton Linac	cavity, DTL, proton, neutron	90
	L.V. Kravchuk, A. Feschenko, M.I. Grachev, V.L. Serov RAS/INR, Moscow, Russia
	Funding: Russian Academy of Science Scientific Complex based on the 600 MeV Proton Linac is under operation at the INR, Troitsk, Moscow to provide both basic and applied research. At the moment proton beam from the Linac with energy about 210 MeV and average current about 130 μA is transporting to the Experimental Area to be use for following facilities: three Spallation Neutron sources, the Isotope Production facility and the Beam Therapy complex. Status of the Linac and Experimental Area as well as the tuning procedures to decrease particle loss in high-intensity mode of operation are given in the paper.
	Slides WEYCH02 [2.281 MB]

WEBCH01	The Status of the SARAF Phase-I Linac	rfq, target, proton, status	103
	L. Weissman, Y. Ben Aliz, D. Berkovits, O. Dudovich, I. Eliyahu, I. Fishman, I.G. Gertz, A. Grin, A. Kreisler, G. Lempert, I. Mardor, A. Perry, E. Reinfeld, J. Rodnizki Soreq NRC, Yavne, Israel
	Phase I of the Soreq Applied Research Accelerator Facility - SARAF is under operation at the Soreq Nuclear Research Center. According to Phase I design specifications, SARAF superconducting linear RF accelerator should yield 2 mA protons and deuterons CW beams at energies up to 4 and 5 MeV, respectively. The status of Phase I main components is reported as well as the beam operation experience accumulated recently. The latter include acceleration of a 1 mA CW protons beam up to 3.5 MeV and 1 mA pulsed, duty cycle of few %, deuterons beam to up to 4.7 MeV. Further planned improvements in the current facility and plans for the future Phase II of the SARAF linac are discussed.
	Slides WEBCH01 [7.617 MB]

THXCH04	Budker INP Free Electron Laser Facility – Current Status and Future Prospects	FEL, undulator, electron, radiation	136
	O.A. Shevchenko, V.S. Arbuzov, K.N. Chernov, E.N. Dementyev, B.A. Dovzhenko, Ya.V. Getmanov, E.I. Gorniker, B.A. Knyazev, E.I. Kolobanov, A.A. Kondakov, V.R. Kozak, E.V. Kozyrev, V.V. Kubarev, G.N. Kulipanov, E.A. Kuper, I.V. Kuptsov, G.Y. Kurkin, L.E. Medvedev, L.A. Mironenko, V.K. Ovchar, B.Z. Persov, A.M. Pilan, V.M. Popik, V.V. Repkov, T.V. Salikova, M.A. Scheglov, I.K. Sedlyarov, G.V. Serdobintsev, S.S. Serednyakov, A.N. Skrinsky, S.V. Tararyshkin, V.G. Tcheskidov, N. Vinokurov, M.G. Vlasenko, P. Vobly, V. Volkov BINP SB RAS, Novosibirsk, Russia
	The free electron laser (FEL) facility at Budker INP is being developed for more than 15 years. It is based on the normal conducting CW energy recovery linac (ERL) with rather complicated magnetic system lattice. Up to now it is the only one in the world multiorbit ERL. It can operate in three different regimes providing electron beam for three different FELs. Its commissioning was naturally divided in three stages. The first stage ERL includes only one orbit placed in vertical plane. It serves as electron beam source for terahertz FEL which started working for users in 2003. Radiation of this FEL is used by several groups of scientists including biologists, chemists and physicists. Its high peak and average powers are utilized in experiments on material ablation and biological objects modification. The second stage ERL is composed of two orbits located in horizontal plane. The second stage FEL is installed on the bypass of the second orbit. The first lasing of this FEL was achieved in 2009. The last stage ERL will include four orbits. Its commissioning is in progress now. In this paper we report the latest results obtained from the operating FELs as well as our progress with the commissioning of the two remaining ERL beamlines. We also discuss possible options for the future upgrade.
	Slides THXCH04 [5.360 MB]

THAOR06	Update on SCRF Development at TRIUMF	cavity, TRIUMF, HOM, cryomodule	152
	V. Zvyagintsev, B. Amini, K. Fong, P.R. Harmer, D. Kishi, P. Kolb, A. Koveshnikov, D. Lang, R.E. Laxdal, A.K. Mitra, N. Muller, C. Schaub, R.W. Shanks, B.S. Waraich, Q. Zheng TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada S.H. Abidi, R.S. Orr University of Toronto, Toronto, Ontario, Canada R. Edinger PAVAC, Richmond, B.C., Canada M. Gusarova, I.I. Petrushina, N.P. Sobenin, D.B. Tikhonov MEPhI, Moscow, Russia A. Vrielink UBC, Vancouver, B.C., Canada
	Since 2007 TRIUMF started development of eLINAC which is a 50 MeV 10 mA CW electron superconducting linear accelerator to be used as a driver to produce radioactive ion beams through photofission. The accelerator is based on five 1.3 GHz TTF/ILC elliptical bulk Nb cavities technology to be mounted in three cryomodules; an injector cryomodule with one cavity and two accelerating modules with two cavities each. The ISAC-II project superconducting heavy ion linear accelerator was successfully completed in 2010 and we now have in operation 40 superconducting bulk Nb QWR cavities assembled in eight cryomodules. Results and plans of the SCRF program and experience of ISAC-II operation at TRIUMF will be discussed.
	Slides THAOR06 [3.309 MB]

FRXOR01	Technique and Instrumentation For Bunch Shape Measurements	electron, target, electromagnetic-fields, ion	181
	A. Feschenko RAS/INR, Moscow, Russia
	Bunch shape is one of the most important, interesting but difficult to observe characteristics of a beam in ion linear accelerators. Different possibilities of bunch shape measurements are considered but the emphasis is put on the Bunch Shape Monitors (BSM) developed in INR RAS. The operation of BSM is based on a coherent transformation of a longitudinal structure of a beam under study into a spatial distribution of a secondary electron beam through rf scanning. BSM characteristics found both by simulations and experimentally are presented; the ultimate parameters and the limitations are discussed. Modifications of BSM are described. Some experimental results of bunch observations are demonstrated.
	Slides FRXOR01 [6.339 MB]

FRBCH02	Project of Low-Energy Accelerator Driven Power Plant	target, neutron, proton, DTL	224
	A.G. Golovkina, D.A. Ovsyannikov St. Petersburg State University, St. Petersburg, Russia A.A. Bogdanov, I.V. Kudinovich, V.P. Struev AN Krylov SRI, St. Petersburg, Russia Y.A. Svistunov NIIEFA, St. Petersburg, Russia
	Project of low-energy accelerator driven nuclear power plant is considered. The accelerator driven system (ADS) with subcritical fast reactor, proton linac and fissile target is proposed. The main performance data of the ADS: proton beam energy 300-400 MeV, accelerator average current 5 mA, reactor thermal power 200 MW, core effective multiplication factor Keff=0.98. The principal design features of the power plant are also represented.
	Slides FRBCH02 [2.663 MB]

MOPPA022	Status of INR DTL RF System	cavity, DTL, vacuum, cathode	293
	A.I. Kvasha, A. Feschenko, V.L. Serov RAS/INR, Moscow, Russia
	INR Linac is in regular operation since 1993. The accelerator incorporates DTL and DAW structures operating at 198.2 MHz and 991 MHz correspondingly. Initially two types of high power vacuum tubes specially designed for INR linac (GI-54A for final amplifier and GI-51A for intermediate amplifier) were used in DTL RF power system. However production of these tubes has been terminated resulting in a need of DTL RF system upgrade. The main goal of the recent upgrade is replacement of the old tubes by modern ones. The difficulty of replacement arises due to a need to minimize mechanical changes of the existing equipment. Another goal is improving of operational reliability. The reliability depends on vacuum tube reliability and to a large extent - on crowbar operation. The results and the experience of INR DTL RF system upgrade are presented

MOPPA023	Investigation of INR DTL RF System Operation at 100 Hz Repetition Rate	DTL, cathode, cavity, controls	296
	V.L. Serov, A.N. Drugakov, A. Feschenko, A.I. Kvasha, A.N. Naboka RAS/INR, Moscow, Russia
	INR Linac has been operating with 50 Hz beam repetition rate so far. Increasing the repetition rate up to 100 Hz is of importance as it results in doubling of the beam intensity. To solve the task several accelerator systems must be modernized but the most critical one is the DTL rf system (up to 100 MeV). The problems related to the DTL rf system repetition rate increasing are described. One of them is a 50 Hz modulation of a 100 Hz rf pulse sequence. Though the instabilities of accelerating field due to the modulation are reduced by the feedback systems, nevertheless exploration of the effect and its minimizing is of importance. The analysis of the effect is given and the results of experimental studies are presented.

TUPPB010	RF Quadrupole Focusing Lattices	rfq, focusing, lattice, quadrupole	331
	A.S. Plastun, T.V. Bondarenko MEPhI, Moscow, Russia
	Spatial homogeneity of a conventional RFQ allows to estimate parameters of the lattice easily. Hybrid-RFQ structures with spatially periodic RFQ lenses are more complicated in respect of beam dynamics. Transverse stability of beam motion is defined by lattice parameters. Basically parameters of RF focusing lattices are influenced by longitudinal emittance of a bunch in contrast to static focusing lattices. The paper presents a method which allows to evaluate parameters of a very wide class of RF and static quadrupole lattices. Transverse acceptance and acceleration rate could be determined. The method is useful to compare Hybrid-RFQ structures with a conventional RFQ.

TUPPB011	Analytical Approach for Beam Matching	ion, simulation, emittance, controls	334
	V.S. Dyubkov, S.M. Polozov MEPhI, Moscow, Russia
	Charge particle beams transportation with small cross-sections and low energies is an actual problem for a gantry. That beams are used actively for isotope therapy. Beam emittance is its quality factor, and it should be matched with a facility channel acceptance. The method for beam dynamics analysis in lattice is developed in terms of non-coherent particle oscillation study. Nonlinear beam dynamics is investigated by using this method. It is shown that this technique allows one to realize effective beam emittance control. Analytical results obtained are verified by means of numerical simulation.

TUPPB012	Search of the Motion Integral at Linac with RF Focusing	focusing, undulator, dynamic-aperture, ion	337
	V.S. Dyubkov, S.M. Polozov MEPhI, Moscow, Russia
	The problem of the effective low-energy linac design is of interest to many fields of science, industry and medicine. It is well known that nonsynchronous harmonics of RF field (RF undulator) are focusing the particles. Analytical beam dynamics investigation can be carried out by means of the averaging method over the rapid oscillations period (the so-called smooth approximation) in the oscillating fields. Motion equation is presented in the form of the Hamilton's equations. Motion integrals are found by means of Poincare mapping.

TUPPB017	Multy Frequency Stored Energy RF Linac	cavity, acceleration, beam-loading, accelerating-gradient	350
	V.G. Kurakin, P.V. Kurakin LPI, Moscow, Russia
	Due to beam loading, accelerating gradient in rf linac is reduced in time if the energy acquired by charged bunches is not compensated by external generator that feeds the linac. Since the bunch energy gain in this mode of operation correlates strongly with bunch number, the energy spectrum of total bunch train might be corrected in order to suppress this additional spectrum widening. This spectrum control might be achieved with the rf cavity that operates at frequency shifted relative the main one in such a way, that any new bunch sees the cavity field in the appropriate phase correlated with bunch number. The first bunch traverses correcting cavity in field node while the last one in the phase, where the energy acquired by this bunch is equal to resulting bunch train energy spread arising from beam loading effect. Equations of beam - rf cavity interactions are derived followed by coherent beam dynamics exploration in the system described. Measures for suppression of non coherent bunches spectrum widening are suggested leading to insertion additional cavity excited at frequency shifted relative the main and adjacent frequencies. Direct Digital Synthesis technique is suggested as well to provide necessary frequencies and phase's correlations in linac. Advantages of proposed technique as well its possible applications are discussed.

TUPPB022	Mathematical Model of Beam Dynamic Optimization	focusing, DTL, emittance, controls	361
	V.V. Altsybeyev St. Petersburg State University, St. Petersburg, Russia
	We treat here the process of simulation of charged particle dynamics using so called hybrid system. Hybrid system is a system with continuous and discrete parts, described by differential and difference equations, respectively. In this case new mathematical model of beam dynamics optimization is suggested. The main parameters of optimization are: coefficient of particle capture in the acceleration mode, phase and energy spectra of particles at the exit of the accelerator, the transverse beam characteristics, etc. Optimization was carried out for the drift tubes accelerator.

TUPPB036	Study of Proton Injector Beam Transverse Phase Space Variations During Accelerating Voltage Pulse	ion, proton, emittance, high-voltage	397
	A. Belov, O.T. Frolov, E.S. Nikulin, V.P. Yakushev, V. Zubets RAS/INR, Moscow, Russia
	The proton injector of INR RAS linac provides a pulsed beam with the following parameters: current – up to 100-120 mA; duration – 200 mks; pulse repetition rate – 50 Hz; energy of ions – 400 keV. The results of numerical calculations and experimental study of beam phase space variations during injector high voltage pulse are presented. It is shown that these variations are caused by instabilities of both beam current and accelerating tube intermediate electrode potential. Instability of beam current has been minimized by using of noiseless mode of operation for the pulsed duoplasmatron and by stabilization of ion source discharge current. The high voltage pulse stability is now better than ±0.1%. High frequency oscillations at high voltage pulse plateau have been diminished by both decreasing of high voltage pulse generator artificial line characteristic impedance and filtration of high frequency component of the diode-capacitor stabilizer rack current. The beam transverse normalized emittance for 90% of beam current has been measured to be of 0.08 pi cm*mrad. Variations of the emittance during the high voltage pulse are in limits of ±4% value.

TUPPB059	Low Energy Channel for Modernized LU-20	rfq, ion, emittance, solenoid	442
	V. Aleksandrov, A. Govorov, V. Monchinsky, G.V. Trubnikov JINR, Dubna, Moscow Region, Russia
	The modernization of LU-20 accelerator expects change existing electrostatic for-injector on RFQ type pre-accelerator. Low energy channel of transportation of beams is offered from three sources of ions: ESIS, LIS and SPIon - to RFQ. Parameters of channel and results of numerical modeling on fitting beams parameters with acceptance of RFQ are presented.

WEPPC001	A Simulation Study on Accelerator Cavities for a SW Linac	cavity, impedance, coupling, simulation	445
	N. Khosravi Zanjan University, Zanjan, Iran E.E. Ebrahimibasabi, S.A.H. Feghhi sbu, Tehran, Iran
	An on axis-coupled cavity structure has been studied using S-band microwaves at 2856 MHz, suitable for industrial and research applications. It uses a bi-periodic SW structure with constant impedance that operates at pi/2 mode. This structure consist Kidney-like shaped slots, placed symmetrically with respect to the accelerating axis. We compared Different shapes, places and sizes of slots with respect to coupling coefficient, resonance frequency and some of cavity parameters. Sensitivity analyses of accelerating cavity on details of structure have been done and their behavior, with respect to the resonance frequency has been presented. According to the simulation result using SUPERFISH and CST Studio package, each accelerating cavity is capable to deliver 0.56 MeV to electrons in a 50 mA beam.

WEPPC002	RF Design and Tuning of Linac4 RFQ	rfq, dipole, quadrupole, controls	448
	A. France, M. Desmons, O. Piquet CEA/DSM/IRFU, France C. Rossi CERN, Geneva, Switzerland
	In the Linac4 (a part of CERN accelerator complex upgrade), a 3 MeV, 3-meter long, 352 MHz RFQ accelerates a 70 mA H⁻ ion beam from source to DTL input energy. RF design and tuning both rely on the same 4-wire transmission model (TLM), which ensures a consistent control of all RF parameters. 3D simulations are used to determine electrical parameters of TLM in the design process. RFQ end-circuits are designed to minimize sensitivity of RFQ voltage profile to perturbations that might occur during operation, and are tuned with quadrupole rods. Slug tuners size and distribution take into account fabrication tolerances and bead-pull measurement constraints. The three 1-meter long RFQ sections are machined and brazed in CERN. RF bead-pull measurements used to estimate RFQ electrical parameters throughout fabrication steps have not revealed any significant departure from expected values. Vacuum ports position is also adjusted prior to braze using RF measurements. Electrical parameters of end-circuits are derived from sets of five linearly independent bead-pull measurements. Slugs are tuned using a closed-loop algorithm, where "command" quantities are tuner positions, "control" quantities are measured fields, and RFQ inverse transfer function is based on the TLM. Tuning convergence and final accuracy will be presented.

WEPPC003	Beam Pulse Separation System of INR Linac	extraction, target, vacuum, cavity	451
	V.L. Serov, N.I. Brusova, A. Feschenko, O.V. Grekhov, Y.Z. Kalinin, V.N. Mikhailov, A.A. Stepanov RAS/INR, Moscow, Russia B.O. Bolshakov, A.V. Pozhensky NIIEFA, St. Petersburg, Russia
	The activity for beam intensity increasing and beam use efficiency improvement is under progress in INR linac. An important stage is the development and implementation of the Beam Pulse Separation System in the accelerator intermediate extraction area (160 MeV). The system is intended for distribution the beam pulses between Isotope Production Facility (up to 160 MeV) and the Experimental Facility located downstream of the accelerator exit. The report describes the upgrade of intermediate extraction area as well as the first results of experiments with the beam.

WEPPC004	Maximum Value of the Standing Wave and Travelling Wave Accelerating Structures Electronic Efficiency	electron, cavity, radiation, coupling	453
	S. Proskin, A. Kulago MEPhI, Moscow, Russia
	A new theoretical approach for a calculation of the standing wave structure electronic efficiency is described. As a result the electronic efficiency of the biperiodic structure is evaluated regarding a new definition

WEPPC005	Extreme Density Charge Electron Bunches	electron, target, radiation, controls	456
	S. Proskin, A. Kulago MEPhI, Moscow, Russia
	This paper presents untraditional approach for obtaining the DLWG limited bunch charge (LBC). The maximum energy of accelerated bunch is considered. As a result the bremsstrahlung maximum dose rate evaluation is obtained

WEPPC008	Biperiodic Accelerating Structure with Inner Coupling Cells with an Increased Coupling Coefficient	coupling, cavity, simulation, multipactoring	458
	M. Gusarova, I.I. Petrushina, E.A. Savin, N.P. Sobenin, D.B. Tikhonov MEPhI, Moscow, Russia
	Results on coupling increase research for biperiodic accelerating structure featuring high effective shunt impedance and other electrodynamical characteristics are presented. Accelerating structure for sample facility was designed taking into consideration thermal issues and multipactor discharge immunity.

WEPPC009	Using Genetic Algorithms for Electrode Shape Optimization in Accelerators with RF Focusing	focusing, simulation, acceleration, controls	461
	A.V. Samoshin, K.A. Aliev, S.M. Polozov MEPhI, Moscow, Russia
	The drift tubes shape choice which provides the require distribution of the spatial harmonics amplitudes of RF field is an important problem in the design of RF focusing accelerators. It is necessary to have various relationships of the main (accelerating) and the first (as main focusing) harmonics of RF field for different types of accelerators. High order harmonics should be negligible for accelerators with an external focusing, and this ratio should be E1/E0 = 3-5 for the efficient operation of the axially symmetric RF focusing accelerator. Thus, the distribution and harmonic amplitude's ratios at the accelerator axis which provides stable beam dynamics are always known. The drift tubes shape study problem cannot be solved directly by ordinary methods because of unknown boundary conditions belongs to a class of ill-posed problem. At present, this problem can be solved by using genetic algorithms (GA). For this purpose, the electrode shape will be represent as the polynomial function, and then solve the Laplace equation with boundary conditions of Dirichlet and Neumann. The necessary electrodes shape can be quickly and easily simulated using the adaptive search.

WEPPC010	H-Cavity Based Accelerating Structure for Proton Accelerator	impedance, proton, simulation, cavity	464
	M.V. Lalayan, A.A. Kalashnikova, S.E. Toporkov MEPhI, Moscow, Russia
	Funding: Work is supported by "scientific stuff" grant of The Ministry of Education and Science of the Russian Federation Cavity for proton accelerator operating in 0.01 to 0.04 phase velocity range optimization results with respect to electrodynamical parameters are presented. H-type based cavity for two operating frequencies 145 MHz and 433 MHz was considered. Influence of cavity shape and dimensions on most important EDCs – relative shunt impedance, quality factor and transient time factor was studied. Influence of high order modes on beam dynamics was considered.

WEPPC047	Operational Experience with 55 MeV Pulsed RTM	klystron, high-voltage, controls, radiation	538
	V.V. Khankin, N.I. Pakhomov, V.I. Shvedunov MSU, Moscow, Russia A.I. Karev, V.G. Raevsky LPI, Moscow, Russia
	Operational experience with 55 MeV RTM * is reported. After RTM commissioning described in * it was installed in specially built bunker with 60-80 cm thick barite concrete walls placed in accelerator hall in order to protect detector equipment from parasitic radiation. New equipment was installed at RTM including new pulsed modulator, high power vacuum window and circulator, new cooling system, additional steering coils. Control system software based on LabView was also modified to make RTM tuning easier. Introduced changes made RTM operation more stable, beam transmission through RTM was improved. After re-commissioning RTM is used for experiments in nuclear physics, in PET isotope production research, in explosive detection experiments etc. *A.I.Karev, A.N.Lebedev, V.G.Raevsky, A.N.Ermakov, A.N.Kamanin, V.V.Khankin, N.I.Pahomov, V.I.Shvedunov, etc., 55 MeV special purpose race-track microtron commissioning, in Proc. RuPAC-2010, p.316-318

WEPPC059	Electron Beam Image Visual Monitoring	electron, monitoring, target, gun	563
	V.N. Boriskin, I.A. Chertishchev, N.G. Reshetnyak, K. Romanovsky, V.A. Shevchenko, I.N. Shlyakhov, A.Eh. Tenishev, V.L. Uvarov, V. Zakutin NSC/KIPT, Kharkov, Ukraine
	The system for visual monitoring of the electron beam features was developed and implemented. This system is based on registration of optical radiation, which is generated under object-beam interaction. The system comprises image transferring channel, remote-controlled digital photo-camera, connected with PC by USB-interface as well as proper software. The images obtained give information on the beam density distribution over the surface of the object being irradiated. 100 KeV and 10 MeV electron beams was researched.

WEPPD004	Longitudinal Stability of ERL with Two Accelerating RF Structures	electron, RF-structure, cavity, simulation	575
	Ya.V. Getmanov, O.A. Shevchenko BINP SB RAS, Novosibirsk, Russia N. Vinokurov KAERI, Daejon, Republic of Korea
	Modern Energy Recovery Linac (ERL) projects use superconductive accelerating radio-frequency structures (RF). Their RF quality is typically very high. Therefore, the RF voltage induced by electron beam is also high. In ERL the RF voltage induced by the accelerating beam is almost cancelled by the RF voltage induced by the decelerating beam. But, a small variation of the RF voltage may cause the deviations of the accelerating phases. These deviations then may cause further voltage variation. Thus, the system may be unstable. The stability conditions for ERL with one accelerating structure are well known. The ERL with split RF structure was discussed recently. The stability conditions for such ERLs are discussed in this paper

WEPPD013	Inverse Compton Sources on the Basis of Electron Accelerators with Beam Energy Recovery	electron, cavity, photon, FEL	593
	V.G. Kurakin, P.V. Kurakin LPI, Moscow, Russia
	In inverse Compton Source, photons in Roentgen range originate from visible light laser photons scattered back on electrons with the energy of dozens MeV. Several schemes are suggested in the paper, beam energy recovery conception being the common idea of all of them. The first one is based on synchrotron with flat part of guiding magnetic field. Being accelerated, electron bunch interacts with photon bunch of free electron laser mounted on straight paths of the accelerator, then is decelerated during falling down period of magnetic field cycle, and extracted at low energy from synchrotron to absorb in beam dump. This measure decreases background that originates from bremsstrahlung of lost electrons inherent to classical schema with linear accelerator and storage ring. Two other schemes use superconducting linac that produces relativistic electron bunches which energy is recovered after use, free electron laser (FEL) driven by bunches from linac being used to produce photons bunches for source. In one scheme the same electron bunches are use to drive FEL and inverse Compton Source, while in the other one beam splitting technique is suggested. It is based on beam energy modulation with subsequent separation of successive bunches. The expected self excitation inverse Compton sources parameters are estimated followed by critical issues discussion for all schemes suggested.

WEPPD030	New Beam Position Monitor Electronics For VEPP-5 Preinjector	positron, electron, background, injection	614
	A.S. Styuf, G.V. Karpov BINP SB RAS, Novosibirsk, Russia
	A new beam position monitor (BPM) electronics has been designed, manufactured and tested in VEPP-5 preinjector. Preinjector BPM system measures position of single electron and positron bunches for each injection cycle. New BPM electronics provides more high sensitivity with respect to existing one developed in 2004. The system can measure the position of bunches with 10⁸ - 10¹⁰ particles per bunch. The resolution of measurements of single bunch is better than 10 mkm for 10¹⁰ particles per bunch. The features of BPM electronics design, the main parameters and results obtained in VEPP-5 preinjector are presented.

WEPPD040	Precision Thermostatic Control for LUE-200 Accelerator Section	controls, neutron, electron, diagnostics	629
	V.N. Zamriy, A.P. Sumbaev JINR, Dubna, Moscow Region, Russia
	According to the design of the IREN facility the system of thermostatting of LUE-200 linac sections is developed. Rated values of linac beam power depend basically on a microwave power input and stability of the phase. The latter is sustained by means of thermostatic control for the sections subject to the powerful microwave warming-up. Demanded both high accuracy of stabilization and low settling time of temperature for linac modes define development of the control system. The precise system of thermostatic control in which composition the programmable PID-controller and the platinum resistance thermometer with accuracy of 0.1%, and also thyristor regulators of heating power up to 15 kVА has been adapted for modes of the IREN microwave facility. The advanced system allows to control both power of heating and a flow of cooling water. The system supervises and changes over modes of the accelerated warming-up and controllable heating and cooling. Both high accuracy of the thermostat and energy saving at a smooth settling of temperature and at the subsequent long-term thermostabilization are substantially improved. Essential speed-up of a preliminary warming-up of the thermostat also is attained.

WEPPD044	Developing of the Synchronization System for Accelerating-Storage Facility ITEP-TWAC	controls, target, heavy-ion, status	641
	A.Y. Orlov, P.N. Alekseev, S.V. Barabin, D.A. Liakin ITEP, Moscow, Russia
	The renovation of the ITEP-TWAC synchronization system is a complex and challenging matter. This system must provide a full-scale timing signal set for all existing and foreseeing modes of operation of the two-ring accelerator facility. Complete design covers all levels of a design hierarchy like decision concerning the new system architecture or basic electronic modules development. In this article we present a description of most important parts of the synchronization system.

WEPPD054	Some Aspects of the Cavity Resonant Frequency Control System Heater Operating Point Choice	cavity, controls, acceleration, DTL	665
	V.V. Grechko, G.I. Yamshikov RAS/INR, Moscow, Russia
	To adjust and to stabilize a resonant frequency of the accelerating cavities INR Linac comprises a Cavity Resonant Frequency Control System (CRFCS). The main final control element of the system is an electric heater (EH). Operating point of EH determines power consumption of the system and rf power feed in duration. Electromagnetic noise originated from thyristor regulators of the heaters and influencing linac electronics also depends on the operating point. One of the most sensitive systems is Fast Beam Interlock System (FBIS) intended for prevention of excessive activation and damage of linac components. To exclude false responses of FBIS and to decrease power consumption of CRFCS operating point of the heater has been shifted to a range of smaller power. This approach has been tested during several beam runs with the following results: no false responses of FRIB were observed; the quality of frequency stabilization during beam runs remained at the same level; relatively rare restarts of RF channels did not increase a downtime to beam time ratio; CRFCS power consumption was decreased twice. The rf power feed in duration increased insignificantly.

WEPPD055	Emittance Measurements at the Exit of INR Linac	emittance, quadrupole, proton, beam-losses	668
	P.I. Reinhardt-Nickoulin, S. Bragin, A. Feschenko, S.A. Gavrilov, N.F. Lebedeva, A.N. Mirzojan, A.N. Naboka, I.V. Vasilyev, O. Volodkevich RAS/INR, Moscow, Russia
	Emittance measurements at the exit of INR linac are of importance for proper beam matching with the beam line of the downstream experimental facility. Emittance ellipses are reconstructed from beam profile data obtained with three wire scanners and one ionization beam cross section monitor (BCSM). A possibility of quadrupole gradients adjustment not only increases the reconstruction accuracy but also enables to find emittances with BCSM data only. The latter provides completely transparent measurements and due to large BCSM range can be done within a wide range of beam currents. The results of measurements done with wire scanners and BCSM are presented and compared, the reconstruction procedure features are discussed.

WEPPD056	Development of INR Linac BCT System	proton, DTL, neutron, acceleration	671
	P.I. Reinhardt-Nickoulin, S. Bragin, V. Gaidash, O.V. Grekhov, Yu.V. Kiselev, N.F. Lebedeva, A.N. Mirzojan, A.N. Naboka, I.V. Vasilyev, O. Volodkevich RAS/INR, Moscow, Russia
	New electronics of automatic BCT system was developed to provide beam intensity measurements along INR linac. BCT electronics details are described. The available results of beam measurements are given.

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Design and Simulation of Practical Alternating-Phase-Focused (APF) Linacs – Synthesis and Extension in Tribute to Pioneering Russian APF Research

focusing, acceleration, emittance, ion

12

R.A. Jameson
IAP, Frankfurt am Main, Germany

Conventional magnetic transverse focusing in conventional linacs represents a high fraction of their cost and complexity. Both transverse and longitudinal focusing can be obtained from the rf field by using the strong-focusing effect of alternating patterns (sequences) of gap phases and amplitudes – known as Alternating-Phase-Focusing (APF). Although studied for decades, the difficulty of designing suitable sequences has inhibited APF adoption, although short sequence APFs are now used in a number of practical applications. Synthesis of reported details and new physics and technique result in a new, general and efficient method for designing APF linacs. Very long sequences with high energy gain factors are demonstrated, e.g. for acceleration of very cold muons from ~0.340-200MeV (factor 600).

Slides MOACH02 [0.616 MB]

WEYCH02

Multipurpose Research Complex Based on the INR High Intensity Proton Linac

cavity, DTL, proton, neutron

90

L.V. Kravchuk, A. Feschenko, M.I. Grachev, V.L. Serov
RAS/INR, Moscow, Russia

Funding: Russian Academy of Science
Scientific Complex based on the 600 MeV Proton Linac is under operation at the INR, Troitsk, Moscow to provide both basic and applied research. At the moment proton beam from the Linac with energy about 210 MeV and average current about 130 μA is transporting to the Experimental Area to be use for following facilities: three Spallation Neutron sources, the Isotope Production facility and the Beam Therapy complex. Status of the Linac and Experimental Area as well as the tuning procedures to decrease particle loss in high-intensity mode of operation are given in the paper.

Slides WEYCH02 [2.281 MB]

WEBCH01

The Status of the SARAF Phase-I Linac

rfq, target, proton, status

103

L. Weissman, Y. Ben Aliz, D. Berkovits, O. Dudovich, I. Eliyahu, I. Fishman, I.G. Gertz, A. Grin, A. Kreisler, G. Lempert, I. Mardor, A. Perry, E. Reinfeld, J. Rodnizki
Soreq NRC, Yavne, Israel

Phase I of the Soreq Applied Research Accelerator Facility - SARAF is under operation at the Soreq Nuclear Research Center. According to Phase I design specifications, SARAF superconducting linear RF accelerator should yield 2 mA protons and deuterons CW beams at energies up to 4 and 5 MeV, respectively. The status of Phase I main components is reported as well as the beam operation experience accumulated recently. The latter include acceleration of a 1 mA CW protons beam up to 3.5 MeV and 1 mA pulsed, duty cycle of few %, deuterons beam to up to 4.7 MeV. Further planned improvements in the current facility and plans for the future Phase II of the SARAF linac are discussed.

Slides WEBCH01 [7.617 MB]

THXCH04

Budker INP Free Electron Laser Facility – Current Status and Future Prospects

FEL, undulator, electron, radiation

136

O.A. Shevchenko, V.S. Arbuzov, K.N. Chernov, E.N. Dementyev, B.A. Dovzhenko, Ya.V. Getmanov, E.I. Gorniker, B.A. Knyazev, E.I. Kolobanov, A.A. Kondakov, V.R. Kozak, E.V. Kozyrev, V.V. Kubarev, G.N. Kulipanov, E.A. Kuper, I.V. Kuptsov, G.Y. Kurkin, L.E. Medvedev, L.A. Mironenko, V.K. Ovchar, B.Z. Persov, A.M. Pilan, V.M. Popik, V.V. Repkov, T.V. Salikova, M.A. Scheglov, I.K. Sedlyarov, G.V. Serdobintsev, S.S. Serednyakov, A.N. Skrinsky, S.V. Tararyshkin, V.G. Tcheskidov, N. Vinokurov, M.G. Vlasenko, P. Vobly, V. Volkov
BINP SB RAS, Novosibirsk, Russia

The free electron laser (FEL) facility at Budker INP is being developed for more than 15 years. It is based on the normal conducting CW energy recovery linac (ERL) with rather complicated magnetic system lattice. Up to now it is the only one in the world multiorbit ERL. It can operate in three different regimes providing electron beam for three different FELs. Its commissioning was naturally divided in three stages. The first stage ERL includes only one orbit placed in vertical plane. It serves as electron beam source for terahertz FEL which started working for users in 2003. Radiation of this FEL is used by several groups of scientists including biologists, chemists and physicists. Its high peak and average powers are utilized in experiments on material ablation and biological objects modification. The second stage ERL is composed of two orbits located in horizontal plane. The second stage FEL is installed on the bypass of the second orbit. The first lasing of this FEL was achieved in 2009. The last stage ERL will include four orbits. Its commissioning is in progress now. In this paper we report the latest results obtained from the operating FELs as well as our progress with the commissioning of the two remaining ERL beamlines. We also discuss possible options for the future upgrade.

Slides THXCH04 [5.360 MB]

THAOR06

Update on SCRF Development at TRIUMF

cavity, TRIUMF, HOM, cryomodule

152

V. Zvyagintsev, B. Amini, K. Fong, P.R. Harmer, D. Kishi, P. Kolb, A. Koveshnikov, D. Lang, R.E. Laxdal, A.K. Mitra, N. Muller, C. Schaub, R.W. Shanks, B.S. Waraich, Q. Zheng
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
S.H. Abidi, R.S. Orr
University of Toronto, Toronto, Ontario, Canada
R. Edinger
PAVAC, Richmond, B.C., Canada
M. Gusarova, I.I. Petrushina, N.P. Sobenin, D.B. Tikhonov
MEPhI, Moscow, Russia
A. Vrielink
UBC, Vancouver, B.C., Canada

Since 2007 TRIUMF started development of eLINAC which is a 50 MeV 10 mA CW electron superconducting linear accelerator to be used as a driver to produce radioactive ion beams through photofission. The accelerator is based on five 1.3 GHz TTF/ILC elliptical bulk Nb cavities technology to be mounted in three cryomodules; an injector cryomodule with one cavity and two accelerating modules with two cavities each. The ISAC-II project superconducting heavy ion linear accelerator was successfully completed in 2010 and we now have in operation 40 superconducting bulk Nb QWR cavities assembled in eight cryomodules. Results and plans of the SCRF program and experience of ISAC-II operation at TRIUMF will be discussed.

Slides THAOR06 [3.309 MB]

FRXOR01

Technique and Instrumentation For Bunch Shape Measurements

electron, target, electromagnetic-fields, ion

181

A. Feschenko
RAS/INR, Moscow, Russia

Bunch shape is one of the most important, interesting but difficult to observe characteristics of a beam in ion linear accelerators. Different possibilities of bunch shape measurements are considered but the emphasis is put on the Bunch Shape Monitors (BSM) developed in INR RAS. The operation of BSM is based on a coherent transformation of a longitudinal structure of a beam under study into a spatial distribution of a secondary electron beam through rf scanning. BSM characteristics found both by simulations and experimentally are presented; the ultimate parameters and the limitations are discussed. Modifications of BSM are described. Some experimental results of bunch observations are demonstrated.

Slides FRXOR01 [6.339 MB]

FRBCH02

Project of Low-Energy Accelerator Driven Power Plant

target, neutron, proton, DTL

224

A.G. Golovkina, D.A. Ovsyannikov
St. Petersburg State University, St. Petersburg, Russia
A.A. Bogdanov, I.V. Kudinovich, V.P. Struev
AN Krylov SRI, St. Petersburg, Russia
Y.A. Svistunov
NIIEFA, St. Petersburg, Russia

Project of low-energy accelerator driven nuclear power plant is considered. The accelerator driven system (ADS) with subcritical fast reactor, proton linac and fissile target is proposed. The main performance data of the ADS: proton beam energy 300-400 MeV, accelerator average current 5 mA, reactor thermal power 200 MW, core effective multiplication factor Keff=0.98. The principal design features of the power plant are also represented.

Slides FRBCH02 [2.663 MB]

MOPPA022

Status of INR DTL RF System

cavity, DTL, vacuum, cathode

293

A.I. Kvasha, A. Feschenko, V.L. Serov
RAS/INR, Moscow, Russia

INR Linac is in regular operation since 1993. The accelerator incorporates DTL and DAW structures operating at 198.2 MHz and 991 MHz correspondingly. Initially two types of high power vacuum tubes specially designed for INR linac (GI-54A for final amplifier and GI-51A for intermediate amplifier) were used in DTL RF power system. However production of these tubes has been terminated resulting in a need of DTL RF system upgrade. The main goal of the recent upgrade is replacement of the old tubes by modern ones. The difficulty of replacement arises due to a need to minimize mechanical changes of the existing equipment. Another goal is improving of operational reliability. The reliability depends on vacuum tube reliability and to a large extent - on crowbar operation. The results and the experience of INR DTL RF system upgrade are presented

MOPPA023

Investigation of INR DTL RF System Operation at 100 Hz Repetition Rate

DTL, cathode, cavity, controls

296

V.L. Serov, A.N. Drugakov, A. Feschenko, A.I. Kvasha, A.N. Naboka
RAS/INR, Moscow, Russia

INR Linac has been operating with 50 Hz beam repetition rate so far. Increasing the repetition rate up to 100 Hz is of importance as it results in doubling of the beam intensity. To solve the task several accelerator systems must be modernized but the most critical one is the DTL rf system (up to 100 MeV). The problems related to the DTL rf system repetition rate increasing are described. One of them is a 50 Hz modulation of a 100 Hz rf pulse sequence. Though the instabilities of accelerating field due to the modulation are reduced by the feedback systems, nevertheless exploration of the effect and its minimizing is of importance. The analysis of the effect is given and the results of experimental studies are presented.

TUPPB010

RF Quadrupole Focusing Lattices

rfq, focusing, lattice, quadrupole

331

A.S. Plastun, T.V. Bondarenko
MEPhI, Moscow, Russia

Spatial homogeneity of a conventional RFQ allows to estimate parameters of the lattice easily. Hybrid-RFQ structures with spatially periodic RFQ lenses are more complicated in respect of beam dynamics. Transverse stability of beam motion is defined by lattice parameters. Basically parameters of RF focusing lattices are influenced by longitudinal emittance of a bunch in contrast to static focusing lattices. The paper presents a method which allows to evaluate parameters of a very wide class of RF and static quadrupole lattices. Transverse acceptance and acceleration rate could be determined. The method is useful to compare Hybrid-RFQ structures with a conventional RFQ.

TUPPB011

Analytical Approach for Beam Matching

ion, simulation, emittance, controls

334

V.S. Dyubkov, S.M. Polozov
MEPhI, Moscow, Russia

Charge particle beams transportation with small cross-sections and low energies is an actual problem for a gantry. That beams are used actively for isotope therapy. Beam emittance is its quality factor, and it should be matched with a facility channel acceptance. The method for beam dynamics analysis in lattice is developed in terms of non-coherent particle oscillation study. Nonlinear beam dynamics is investigated by using this method. It is shown that this technique allows one to realize effective beam emittance control. Analytical results obtained are verified by means of numerical simulation.

TUPPB012

Search of the Motion Integral at Linac with RF Focusing

focusing, undulator, dynamic-aperture, ion

337

V.S. Dyubkov, S.M. Polozov
MEPhI, Moscow, Russia

The problem of the effective low-energy linac design is of interest to many fields of science, industry and medicine. It is well known that nonsynchronous harmonics of RF field (RF undulator) are focusing the particles. Analytical beam dynamics investigation can be carried out by means of the averaging method over the rapid oscillations period (the so-called smooth approximation) in the oscillating fields. Motion equation is presented in the form of the Hamilton's equations. Motion integrals are found by means of Poincare mapping.

TUPPB017

Multy Frequency Stored Energy RF Linac

cavity, acceleration, beam-loading, accelerating-gradient

350

V.G. Kurakin, P.V. Kurakin
LPI, Moscow, Russia

Due to beam loading, accelerating gradient in rf linac is reduced in time if the energy acquired by charged bunches is not compensated by external generator that feeds the linac. Since the bunch energy gain in this mode of operation correlates strongly with bunch number, the energy spectrum of total bunch train might be corrected in order to suppress this additional spectrum widening. This spectrum control might be achieved with the rf cavity that operates at frequency shifted relative the main one in such a way, that any new bunch sees the cavity field in the appropriate phase correlated with bunch number. The first bunch traverses correcting cavity in field node while the last one in the phase, where the energy acquired by this bunch is equal to resulting bunch train energy spread arising from beam loading effect. Equations of beam - rf cavity interactions are derived followed by coherent beam dynamics exploration in the system described. Measures for suppression of non coherent bunches spectrum widening are suggested leading to insertion additional cavity excited at frequency shifted relative the main and adjacent frequencies. Direct Digital Synthesis technique is suggested as well to provide necessary frequencies and phase's correlations in linac. Advantages of proposed technique as well its possible applications are discussed.

TUPPB022

Mathematical Model of Beam Dynamic Optimization

focusing, DTL, emittance, controls

361

V.V. Altsybeyev
St. Petersburg State University, St. Petersburg, Russia

We treat here the process of simulation of charged particle dynamics using so called hybrid system. Hybrid system is a system with continuous and discrete parts, described by differential and difference equations, respectively. In this case new mathematical model of beam dynamics optimization is suggested. The main parameters of optimization are: coefficient of particle capture in the acceleration mode, phase and energy spectra of particles at the exit of the accelerator, the transverse beam characteristics, etc. Optimization was carried out for the drift tubes accelerator.

TUPPB036

Study of Proton Injector Beam Transverse Phase Space Variations During Accelerating Voltage Pulse

ion, proton, emittance, high-voltage

397

A. Belov, O.T. Frolov, E.S. Nikulin, V.P. Yakushev, V. Zubets
RAS/INR, Moscow, Russia

The proton injector of INR RAS linac provides a pulsed beam with the following parameters: current – up to 100-120 mA; duration – 200 mks; pulse repetition rate – 50 Hz; energy of ions – 400 keV. The results of numerical calculations and experimental study of beam phase space variations during injector high voltage pulse are presented. It is shown that these variations are caused by instabilities of both beam current and accelerating tube intermediate electrode potential. Instability of beam current has been minimized by using of noiseless mode of operation for the pulsed duoplasmatron and by stabilization of ion source discharge current. The high voltage pulse stability is now better than ±0.1%. High frequency oscillations at high voltage pulse plateau have been diminished by both decreasing of high voltage pulse generator artificial line characteristic impedance and filtration of high frequency component of the diode-capacitor stabilizer rack current. The beam transverse normalized emittance for 90% of beam current has been measured to be of 0.08 pi cm*mrad. Variations of the emittance during the high voltage pulse are in limits of ±4% value.

TUPPB059

Low Energy Channel for Modernized LU-20

rfq, ion, emittance, solenoid

442

V. Aleksandrov, A. Govorov, V. Monchinsky, G.V. Trubnikov
JINR, Dubna, Moscow Region, Russia

The modernization of LU-20 accelerator expects change existing electrostatic for-injector on RFQ type pre-accelerator. Low energy channel of transportation of beams is offered from three sources of ions: ESIS, LIS and SPIon - to RFQ. Parameters of channel and results of numerical modeling on fitting beams parameters with acceptance of RFQ are presented.

WEPPC001

A Simulation Study on Accelerator Cavities for a SW Linac

cavity, impedance, coupling, simulation

445

N. Khosravi
Zanjan University, Zanjan, Iran
E.E. Ebrahimibasabi, S.A.H. Feghhi
sbu, Tehran, Iran

An on axis-coupled cavity structure has been studied using S-band microwaves at 2856 MHz, suitable for industrial and research applications. It uses a bi-periodic SW structure with constant impedance that operates at pi/2 mode. This structure consist Kidney-like shaped slots, placed symmetrically with respect to the accelerating axis. We compared Different shapes, places and sizes of slots with respect to coupling coefficient, resonance frequency and some of cavity parameters. Sensitivity analyses of accelerating cavity on details of structure have been done and their behavior, with respect to the resonance frequency has been presented. According to the simulation result using SUPERFISH and CST Studio package, each accelerating cavity is capable to deliver 0.56 MeV to electrons in a 50 mA beam.

WEPPC002

RF Design and Tuning of Linac4 RFQ

rfq, dipole, quadrupole, controls

448

A. France, M. Desmons, O. Piquet
CEA/DSM/IRFU, France
C. Rossi
CERN, Geneva, Switzerland

In the Linac4 (a part of CERN accelerator complex upgrade), a 3 MeV, 3-meter long, 352 MHz RFQ accelerates a 70 mA H⁻ ion beam from source to DTL input energy. RF design and tuning both rely on the same 4-wire transmission model (TLM), which ensures a consistent control of all RF parameters. 3D simulations are used to determine electrical parameters of TLM in the design process. RFQ end-circuits are designed to minimize sensitivity of RFQ voltage profile to perturbations that might occur during operation, and are tuned with quadrupole rods. Slug tuners size and distribution take into account fabrication tolerances and bead-pull measurement constraints. The three 1-meter long RFQ sections are machined and brazed in CERN. RF bead-pull measurements used to estimate RFQ electrical parameters throughout fabrication steps have not revealed any significant departure from expected values. Vacuum ports position is also adjusted prior to braze using RF measurements. Electrical parameters of end-circuits are derived from sets of five linearly independent bead-pull measurements. Slugs are tuned using a closed-loop algorithm, where "command" quantities are tuner positions, "control" quantities are measured fields, and RFQ inverse transfer function is based on the TLM. Tuning convergence and final accuracy will be presented.

WEPPC003

Beam Pulse Separation System of INR Linac

extraction, target, vacuum, cavity

451

V.L. Serov, N.I. Brusova, A. Feschenko, O.V. Grekhov, Y.Z. Kalinin, V.N. Mikhailov, A.A. Stepanov
RAS/INR, Moscow, Russia
B.O. Bolshakov, A.V. Pozhensky
NIIEFA, St. Petersburg, Russia

The activity for beam intensity increasing and beam use efficiency improvement is under progress in INR linac. An important stage is the development and implementation of the Beam Pulse Separation System in the accelerator intermediate extraction area (160 MeV). The system is intended for distribution the beam pulses between Isotope Production Facility (up to 160 MeV) and the Experimental Facility located downstream of the accelerator exit. The report describes the upgrade of intermediate extraction area as well as the first results of experiments with the beam.

WEPPC004

Maximum Value of the Standing Wave and Travelling Wave Accelerating Structures Electronic Efficiency

electron, cavity, radiation, coupling

453

S. Proskin, A. Kulago
MEPhI, Moscow, Russia

A new theoretical approach for a calculation of the standing wave structure electronic efficiency is described. As a result the electronic efficiency of the biperiodic structure is evaluated regarding a new definition

WEPPC005

Extreme Density Charge Electron Bunches

electron, target, radiation, controls

456

S. Proskin, A. Kulago
MEPhI, Moscow, Russia

This paper presents untraditional approach for obtaining the DLWG limited bunch charge (LBC). The maximum energy of accelerated bunch is considered. As a result the bremsstrahlung maximum dose rate evaluation is obtained

WEPPC008

Biperiodic Accelerating Structure with Inner Coupling Cells with an Increased Coupling Coefficient

coupling, cavity, simulation, multipactoring

458

M. Gusarova, I.I. Petrushina, E.A. Savin, N.P. Sobenin, D.B. Tikhonov
MEPhI, Moscow, Russia

Results on coupling increase research for biperiodic accelerating structure featuring high effective shunt impedance and other electrodynamical characteristics are presented. Accelerating structure for sample facility was designed taking into consideration thermal issues and multipactor discharge immunity.

WEPPC009

Using Genetic Algorithms for Electrode Shape Optimization in Accelerators with RF Focusing

focusing, simulation, acceleration, controls

461

A.V. Samoshin, K.A. Aliev, S.M. Polozov
MEPhI, Moscow, Russia

The drift tubes shape choice which provides the require distribution of the spatial harmonics amplitudes of RF field is an important problem in the design of RF focusing accelerators. It is necessary to have various relationships of the main (accelerating) and the first (as main focusing) harmonics of RF field for different types of accelerators. High order harmonics should be negligible for accelerators with an external focusing, and this ratio should be E1/E0 = 3-5 for the efficient operation of the axially symmetric RF focusing accelerator. Thus, the distribution and harmonic amplitude's ratios at the accelerator axis which provides stable beam dynamics are always known. The drift tubes shape study problem cannot be solved directly by ordinary methods because of unknown boundary conditions belongs to a class of ill-posed problem. At present, this problem can be solved by using genetic algorithms (GA). For this purpose, the electrode shape will be represent as the polynomial function, and then solve the Laplace equation with boundary conditions of Dirichlet and Neumann. The necessary electrodes shape can be quickly and easily simulated using the adaptive search.

WEPPC010

H-Cavity Based Accelerating Structure for Proton Accelerator

impedance, proton, simulation, cavity

464

M.V. Lalayan, A.A. Kalashnikova, S.E. Toporkov
MEPhI, Moscow, Russia

Funding: Work is supported by "scientific stuff" grant of The Ministry of Education and Science of the Russian Federation
Cavity for proton accelerator operating in 0.01 to 0.04 phase velocity range optimization results with respect to electrodynamical parameters are presented. H-type based cavity for two operating frequencies 145 MHz and 433 MHz was considered. Influence of cavity shape and dimensions on most important EDCs – relative shunt impedance, quality factor and transient time factor was studied. Influence of high order modes on beam dynamics was considered.

WEPPC047

Operational Experience with 55 MeV Pulsed RTM

klystron, high-voltage, controls, radiation

538

V.V. Khankin, N.I. Pakhomov, V.I. Shvedunov
MSU, Moscow, Russia
A.I. Karev, V.G. Raevsky
LPI, Moscow, Russia

Operational experience with 55 MeV RTM * is reported. After RTM commissioning described in * it was installed in specially built bunker with 60-80 cm thick barite concrete walls placed in accelerator hall in order to protect detector equipment from parasitic radiation. New equipment was installed at RTM including new pulsed modulator, high power vacuum window and circulator, new cooling system, additional steering coils. Control system software based on LabView was also modified to make RTM tuning easier. Introduced changes made RTM operation more stable, beam transmission through RTM was improved. After re-commissioning RTM is used for experiments in nuclear physics, in PET isotope production research, in explosive detection experiments etc.
*A.I.Karev, A.N.Lebedev, V.G.Raevsky, A.N.Ermakov, A.N.Kamanin, V.V.Khankin, N.I.Pahomov, V.I.Shvedunov, etc., 55 MeV special purpose race-track microtron commissioning, in Proc. RuPAC-2010, p.316-318

WEPPC059

Electron Beam Image Visual Monitoring

electron, monitoring, target, gun

563

V.N. Boriskin, I.A. Chertishchev, N.G. Reshetnyak, K. Romanovsky, V.A. Shevchenko, I.N. Shlyakhov, A.Eh. Tenishev, V.L. Uvarov, V. Zakutin
NSC/KIPT, Kharkov, Ukraine

The system for visual monitoring of the electron beam features was developed and implemented. This system is based on registration of optical radiation, which is generated under object-beam interaction. The system comprises image transferring channel, remote-controlled digital photo-camera, connected with PC by USB-interface as well as proper software. The images obtained give information on the beam density distribution over the surface of the object being irradiated. 100 KeV and 10 MeV electron beams was researched.

WEPPD004

Longitudinal Stability of ERL with Two Accelerating RF Structures

electron, RF-structure, cavity, simulation

575

Ya.V. Getmanov, O.A. Shevchenko
BINP SB RAS, Novosibirsk, Russia
N. Vinokurov
KAERI, Daejon, Republic of Korea

Modern Energy Recovery Linac (ERL) projects use superconductive accelerating radio-frequency structures (RF). Their RF quality is typically very high. Therefore, the RF voltage induced by electron beam is also high. In ERL the RF voltage induced by the accelerating beam is almost cancelled by the RF voltage induced by the decelerating beam. But, a small variation of the RF voltage may cause the deviations of the accelerating phases. These deviations then may cause further voltage variation. Thus, the system may be unstable. The stability conditions for ERL with one accelerating structure are well known. The ERL with split RF structure was discussed recently. The stability conditions for such ERLs are discussed in this paper

WEPPD013

Inverse Compton Sources on the Basis of Electron Accelerators with Beam Energy Recovery

electron, cavity, photon, FEL

593

V.G. Kurakin, P.V. Kurakin
LPI, Moscow, Russia

In inverse Compton Source, photons in Roentgen range originate from visible light laser photons scattered back on electrons with the energy of dozens MeV. Several schemes are suggested in the paper, beam energy recovery conception being the common idea of all of them. The first one is based on synchrotron with flat part of guiding magnetic field. Being accelerated, electron bunch interacts with photon bunch of free electron laser mounted on straight paths of the accelerator, then is decelerated during falling down period of magnetic field cycle, and extracted at low energy from synchrotron to absorb in beam dump. This measure decreases background that originates from bremsstrahlung of lost electrons inherent to classical schema with linear accelerator and storage ring. Two other schemes use superconducting linac that produces relativistic electron bunches which energy is recovered after use, free electron laser (FEL) driven by bunches from linac being used to produce photons bunches for source. In one scheme the same electron bunches are use to drive FEL and inverse Compton Source, while in the other one beam splitting technique is suggested. It is based on beam energy modulation with subsequent separation of successive bunches. The expected self excitation inverse Compton sources parameters are estimated followed by critical issues discussion for all schemes suggested.

WEPPD030

New Beam Position Monitor Electronics For VEPP-5 Preinjector

positron, electron, background, injection

614

A.S. Styuf, G.V. Karpov
BINP SB RAS, Novosibirsk, Russia

A new beam position monitor (BPM) electronics has been designed, manufactured and tested in VEPP-5 preinjector. Preinjector BPM system measures position of single electron and positron bunches for each injection cycle. New BPM electronics provides more high sensitivity with respect to existing one developed in 2004. The system can measure the position of bunches with 10⁸ - 10¹⁰ particles per bunch. The resolution of measurements of single bunch is better than 10 mkm for 10¹⁰ particles per bunch. The features of BPM electronics design, the main parameters and results obtained in VEPP-5 preinjector are presented.

WEPPD040

Precision Thermostatic Control for LUE-200 Accelerator Section

controls, neutron, electron, diagnostics

629

V.N. Zamriy, A.P. Sumbaev
JINR, Dubna, Moscow Region, Russia

According to the design of the IREN facility the system of thermostatting of LUE-200 linac sections is developed. Rated values of linac beam power depend basically on a microwave power input and stability of the phase. The latter is sustained by means of thermostatic control for the sections subject to the powerful microwave warming-up. Demanded both high accuracy of stabilization and low settling time of temperature for linac modes define development of the control system. The precise system of thermostatic control in which composition the programmable PID-controller and the platinum resistance thermometer with accuracy of 0.1%, and also thyristor regulators of heating power up to 15 kVА has been adapted for modes of the IREN microwave facility. The advanced system allows to control both power of heating and a flow of cooling water. The system supervises and changes over modes of the accelerated warming-up and controllable heating and cooling. Both high accuracy of the thermostat and energy saving at a smooth settling of temperature and at the subsequent long-term thermostabilization are substantially improved. Essential speed-up of a preliminary warming-up of the thermostat also is attained.

WEPPD044

Developing of the Synchronization System for Accelerating-Storage Facility ITEP-TWAC

controls, target, heavy-ion, status

641

A.Y. Orlov, P.N. Alekseev, S.V. Barabin, D.A. Liakin
ITEP, Moscow, Russia

The renovation of the ITEP-TWAC synchronization system is a complex and challenging matter. This system must provide a full-scale timing signal set for all existing and foreseeing modes of operation of the two-ring accelerator facility. Complete design covers all levels of a design hierarchy like decision concerning the new system architecture or basic electronic modules development. In this article we present a description of most important parts of the synchronization system.

WEPPD054

Some Aspects of the Cavity Resonant Frequency Control System Heater Operating Point Choice

cavity, controls, acceleration, DTL

665

V.V. Grechko, G.I. Yamshikov
RAS/INR, Moscow, Russia

To adjust and to stabilize a resonant frequency of the accelerating cavities INR Linac comprises a Cavity Resonant Frequency Control System (CRFCS). The main final control element of the system is an electric heater (EH). Operating point of EH determines power consumption of the system and rf power feed in duration. Electromagnetic noise originated from thyristor regulators of the heaters and influencing linac electronics also depends on the operating point. One of the most sensitive systems is Fast Beam Interlock System (FBIS) intended for prevention of excessive activation and damage of linac components. To exclude false responses of FBIS and to decrease power consumption of CRFCS operating point of the heater has been shifted to a range of smaller power. This approach has been tested during several beam runs with the following results: no false responses of FRIB were observed; the quality of frequency stabilization during beam runs remained at the same level; relatively rare restarts of RF channels did not increase a downtime to beam time ratio; CRFCS power consumption was decreased twice. The rf power feed in duration increased insignificantly.

WEPPD055

Emittance Measurements at the Exit of INR Linac

emittance, quadrupole, proton, beam-losses

668

P.I. Reinhardt-Nickoulin, S. Bragin, A. Feschenko, S.A. Gavrilov, N.F. Lebedeva, A.N. Mirzojan, A.N. Naboka, I.V. Vasilyev, O. Volodkevich
RAS/INR, Moscow, Russia

Emittance measurements at the exit of INR linac are of importance for proper beam matching with the beam line of the downstream experimental facility. Emittance ellipses are reconstructed from beam profile data obtained with three wire scanners and one ionization beam cross section monitor (BCSM). A possibility of quadrupole gradients adjustment not only increases the reconstruction accuracy but also enables to find emittances with BCSM data only. The latter provides completely transparent measurements and due to large BCSM range can be done within a wide range of beam currents. The results of measurements done with wire scanners and BCSM are presented and compared, the reconstruction procedure features are discussed.

WEPPD056

Development of INR Linac BCT System

proton, DTL, neutron, acceleration

671

P.I. Reinhardt-Nickoulin, S. Bragin, V. Gaidash, O.V. Grekhov, Yu.V. Kiselev, N.F. Lebedeva, A.N. Mirzojan, A.N. Naboka, I.V. Vasilyev, O. Volodkevich
RAS/INR, Moscow, Russia

New electronics of automatic BCT system was developed to provide beam intensity measurements along INR linac. BCT electronics details are described. The available results of beam measurements are given.