LINAC2014 - List of Keywords (focusing)

Paper	Title	Other Keywords	Page
MOPP003	A Compact Linac Design for an Accelerator Driven System	linac, cavity, cryomodule, lattice	52
	B. Mustapha, S.V. Kutsaev, J.A. Nolen, P.N. Ostroumov ANL, Argonne, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. A compact linac design has been developed for an Accelerator Driven System (ADS). The linac is under 150 meters in length and comprises a radio-frequency quadrupole (RFQ) and 20 superconducting modules. Three types of half-wave cavities and two types of elliptical cavities have been designed and optimized for high performance at frequencies of 162.5, 325 and 650 MHz. The lattice is being designed and optimized for operation with a peak power of 25 MW for a 25 mA – 1 GeV proton beam. The cavities RF design as well as the linac lattice will be presented along with end-to-end beam dynamics simulations for beam currents ranging from 0 to 25 mA.

MOPP034	Beam Dynamics Studies of the CLIC Drive Beam Injector	bunching, emittance, cavity, quadrupole	131
	S. Sanaye Hajari, S. Döbert, H. Shaker CERN, Geneva, Switzerland S. Sanaye Hajari, H. Shaker IPM, Tehran, Iran
	In the Compact Linear Collider (CLIC) the RF power for the acceleration of the Main Beam is extracted from a high-current Drive Beam that runs parallel with the main linac. The beam in the Drive Beam Accelerator is phase coded. This means only every second accelerator bucket is occupied. However, a few percent of particles are captured in wrong buckets, called satellite bunches. The phase coding is done via a sub-harmonic bunching system operating at a half the acceleration frequency. The beam dynamics of the Drive Beam injector complex has been studied in detail and optimised. The model consists of a thermionic gun, the bunching system followed by some accelerating structures and a magnetic chicane. The bunching system contains three sub-harmonic bunchers, a prebuncher and a tapered travelling wave buncher all embedded in a solenoidal magnetic field. The simulation of the beam dynamics has been carried out with PARMELA with the goal of optimising the overall bunching process and in particular decreasing the satellite population and the beam loss in magnetic chicane and in transverse plane limiting the beam emittance growth.

MOPP083	Helical Waveguides for Short Wavelength Accelerators and RF Undulators	undulator, electron, FEL, radiation	248
	S.V. Kuzikov, A.V. Savilov, A.A. Vikharev IAP/RAS, Nizhny Novgorod, Russia A.V. Savilov NNGU, Nizhny Novgorod, Russia
	The short wavelength accelerating structure can combine properties of a linear accelerator and a damping ring simultaneously. It provides acceleration of straight on-axis beam as well as cooling of this beam due to the synchrotron radiation of particles. These properties are provided by specific slow eigen mode which consists of two partial waves, TM01 and TM11. The flying RF undulator introduces a high-power short pulse, propagating in a long helically corrugated waveguide where the -1st space harmonic with negative phase velocity is responsible for particle wiggling. High group velocity allows providing long interaction of particles with RF pulse. Calculations show that RF undulator with period 5 mm, undulator parameter 0.1 is possible in 1 GW 10 ns pulse at frequency 30 GHz. The eigen mode in a helical undulator might have 0th harmonic phase velocity equal to light velocity. Such wave can be excited by relativistic drive bunch in the waveguide where witness bunch follows after the drive bunch, wiggles in wakefields, and generates X-rays at whole waveguide length. Helical waveguides can also be used in order to channel low-energy bunches in RF undulator of THz FEL.
	Poster MOPP083 [2.139 MB]

MOPP095	Emittance Measurement for SPring-8 Linac Using Four Six-Electrode BPMs	emittance, linac, electron, quadrupole	279
	K. Yanagida, H. Hanaki, S. Suzuki JASRI/SPring-8, Hyogo-ken, Japan
	In the SPring-8 linear accelerator (linac) six-electrode beam position monitors (BPMs) have been installed to measure second-order moments. At the end of the linac where the electron beam energy is 1 GeV four quadrupole magnets are utilized for twiss parameter matching toward the following beam transport line. Last year four six-electrode BPMs were installed at the locations of these four quadrupole magnets for an emittance measurement. The relative second-order moments were obtained changing the magnetic field strength of the quadrupole magnets, then beam sizes, emittances and twiss parameters were deduced or calculated. At this time we applied one pair of beam sizes measured by the screen monitor for a precise determination of emittances but we try to implement non-destructive measurement with no screen monitor. Before the emittance measurement a calibration with fifth-order moment correction was carried out changing beam positions at the BPM locations using upstream steering magnets (the entire calibration).
	Slides MOPP095 [0.984 MB]

TUPP045	Beam Physics Challenge in FRIB Driver Linac	linac, ion, proton, acceleration	532
	Y. Yamazaki, N.K. Bultman, A. Facco, Z.Q. He, M. Ikegami, M.J. Johnson, S.M. Lidia, F. Marti, G. Pozdeyev, K. Saito, J. Wei, X. Wu, Y. Zhang, Q. Zhao FRIB, East Lansing, Michigan, USA
	Funding: *Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. The Facility for Rare Isotope Beams driver linac provides CW beams of all the stable ions (from protons to uranium) with a beam power of 400 kW and a minimum beam energy of 200 MeV/u in order to produce a wide variety of rare isotopes, mainly for nuclear physics study. The low beam emittances, both transverse and longitudinal, are key performance requirements, together with beam stability. These are required for efficiently separating one isotope from another, the reason for choosing this linac configuration. Multi-charge states (five charge states for the uranium case) are accelerated for maximizing the beam current, while keeping the low emittances. The efficient acceleration of high beam currents from 0.5 MeV/u through the superconducting linac is, needless to say, one of the biggest challenges. The beam power is more than 200 times higher than existing similar SC heavy ion linac. In particular, the SC cavities are difficult to protect from heavy ion beam damage, which can be 30 times larger locally than a proton beam with the same beam power. Other challenges peculiar to the FRIB linac will be presented, together with the solutions.

TUPP063	Improvements of the LORASR Code and their Impact on Current Beam Dynamics Designs	linac, proton, DTL, quadrupole	569
	R. Tiede, D. Mäder, N.F. Petry, H. Podlech, U. Ratzinger, C. Zhang IAP, Frankfurt am Main, Germany
	LORASR is a multi-particle tracking code optimized for the beam dynamics design of ‘Combined Zero Degree Structure (KONUS)’ lattices, which can benefit from an adapted input file structure and code architecture. Recent code developments focused on the implementation of tools for machine error studies and loss profile investigations, including also steering correction strategies. These tools are a stringent necessity for the design of high intensity linacs. Thus, the abilities of the present LORASR release allow performing a manifold of checks and optimizations before finalizing the layouts of KONUS-based or conventional linacs. Two representative examples are the MAX-MYRRHA Injector and the GSI FAIR Facility Proton Linac, both under development with strong participation of IAP, Frankfurt University. This paper presents the status of the LORASR code development with focus on the new features and illustrates the impact on current designs by examples taken from the above-mentioned projects.

TUPP090	Spatially Periodic RF Quadrupole LINAC	quadrupole, linac, ion, lattice	634
	A.S. Plastun, A. Kolomiets ITEP, Moscow, Russia
	Spatially-periodic RF quadrupole structure is proposed as second section of front end of ion linac. It consists of conventional drift tubes and RF quadrupoles. Quadrupoles are 4-vane segments with nonzero electric potential on the longitudinal axis. Thus the accelerating electric field is formed between drift tubes and RF quadrupoles. Moreover accelerating field can be provided even inside the RF quadrupoles. It allows building structures with different focusing lattices and provides high energy gain rate.
	Poster TUPP090 [7.706 MB]

TUPP110	Quasi Nonlinear Plasma Wakefield Acceleration Experiments	plasma, electron, experiment, emittance	680
	S.K. Barber, G. Andonian, B.D. O'Shea, J.B. Rosenzweig, Y. Sakai, O. Williams UCLA, Los Angeles, USA M. Ferrario INFN/LNF, Frascati (Roma), Italy P. Muggli MPI, Muenchen, Germany
	It is generally agreed that the best way forward for beam driven plasma wakefield acceleration (PWFA) is in the nonlinear or blowout regime. In this regime the expulsion of the plasma electrons from the beam occupied region produces a linear transverse focusing effect and position independent longitudinal accelerating fields, which can, in principle, produce high quality beams accelerated over many meters. However, certain aspects of a linear plasma response can be advantageous, such as the possibility for resonant excitation of wakefields through the use of pulse trains. Exploiting advantages of both linear and nonlinear PWFA may be achievable through the use of low emittance and tightly focused beams with relatively small charge. In this case the beam density can be greater than that of the ambient plasma while simultaneously having a smaller total charge than the plasma electrons contained in a cubic plasma skin depth allowing for blowout in the region of the beam while simultaneously maintaining a quasi linear response in the bulk plasma. Recent experiments at BNL have been aimed at probing various salient aspects of this regime and are presented here.

THPP055	High Power Density Test of PXIE MEBT Absorber Prototype	simulation, radiation, electron, experiment	973
	A.V. Shemyakin, C.M. Baffes Fermilab, Batavia, Illinois, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy One of the goals of the PXIE program at Fermilab is to demonstrate the capability to form an arbitrary bunch pattern from an initially CW 162.5 MHz H⁻ bunch train coming out of an RFQ. The bunch-by-bunch selection will take place in the 2.1 MeV Medium Energy Beam Transport (MEBT) by directing the undesired bunches onto an absorber that needs to withstand a beam power of up to 21 kW, focused onto a spot with a ~2 mm rms radius. Two prototypes of the absorber were manufactured from molybdenum alloy TZM, and tested with a 28 keV DC electron beam up to the peak surface power density required for PXIE, 17W/mm2. Temperatures and flow parameters were measured and compared to analysis. This paper describes the absorber prototypes and key testing results.

THPP065	Acceleration of Intense Flat Beams in Periodic Lattices	emittance, DTL, space-charge, acceleration	1001
	L. Groening, C. Xiao GSI, Darmstadt, Germany I. Hofmann TEMF, TU Darmstadt, Darmstadt, Germany
	Recently a scheme for creation of flat ion beams from linacs has been proposed to increase the efficiency of multi-turn-injection. The proof of principle experiment shall be performed at GSI in Summer 2014. Since the scheme requires charge stripping, it may be necessary to perform the round-to-flat transformation prior to acceleration to the final energy of the linac. This requires preservation of the beam flatness during acceleration along the drift tube linac. This contribution is on simulations of acceleration of flat beams subject to considerable space charge tune depression. It is shown that the flatness can be preserved if the transverse tunes are properly chosen and if mis-match along inter-tank sections is minimized along the DTL.

THPP070	Alternative Compact LEBT Design for the FAIR Injector Upgrade	ion, space-charge, rfq, emittance	1013
	K. Schulte, M. Droba, S. Klaproth, O. Meusel, D. Noll, U. Ratzinger IAP, Frankfurt am Main, Germany S.G. Yaramyshev GSI, Darmstadt, Germany
	In order to provide high intensity and brightness of the uranium beam for the planned FAIR project, the existing High Current Injector (HSI) at GSI has to be upgraded. A part of the upgrade program is the design and construction of a compact straight injection line into the 36 MHz Radio Frequency Quadrupole of the HSI. As an alternative to a conventional LEBT design consisting of magnetic systems such as solenoids or quadrupoles, the application of Gabor lenses has been investigated. The focusing force of the Gabor lens is created by the space charge of an electron cloud, confined by crossed magnetic and electric fields inside the lens volume. Therefore, the Gabor lens combines strong, electrostatic focusing with simultaneous space-charge compensation. In previously performed beam transport experiments at GSI a prototype Gabor lens has been tested successfully. Furthermore, the operation and performance of such a device in a real accelerator environment has been studied. In this contribution an alternative LEBT design will be discussed and an improved Gabor lens design will be presented. W. Barth et al., “HSI-Frontend Upgrade”, GSI Scientific Report, 2009

THPP105	Beam Dynamics Simulation for the 1 GeV High Power Proton Linac	linac, rfq, proton, simulation	1099
	S.M. Polozov, V.S. Dyubkov, T. Kulevoy, A.V. Samoshin MEPhI, Moscow, Russia G. Kropachev, T. Kulevoy ITEP, Moscow, Russia
	Funding: This work is supported in part by the Ministry of Science and Education of Russian Federation under contract No. 14.516.11.0084 The design of high energy and high power proton linacs for accelerating driven systems (ADS) is one of the accelerator technology frontiers. Such linacs are under developing in EU, Japan, PRC but not discussed in Russia previous fifteen years. The driver linac and the breeder conceptual designs were funded by the Ministry of Science and Education of Russian Federation in 2013. The 2 MeV RFQ linac was proposed as the first accelerating section. A number of RF focusing sections types (by RF crossed lenses, modified electrode profile RFQ, axi-symmetrical RF focusing) were discussed for medium energies. The conventional modular scheme linac based on spoke-cavities and 5-cell elliptical cavities was designed for higher energies. The results of beam dynamics simulation in this linac will present.

THPP129	Carbon Field Emission Strip Cathode Electron Source	electron, cathode, simulation, vacuum	1
	T.V. Bondarenko, A.I. Botyachkova, G.G. Karpinskiy, S.A. Polikhov, G.B. Sharkov Siemens Research Center, Moscow,, Russia A.I. Botyachkova, G.G. Karpinskiy National Research Nuclear University (MEPhI), Moscow, Russia A.E. Geisler, O. Heid Siemens AG, Erlangen, Germany
	Over the recent years carbon nanostructure cathodes have become promising as a high brightness electron sources with large working area for field emission structures. Measurements and calculations of a field emission strip cathode based on carbon structure and a unit for its investigation are presented in the article. For measuring of the cathode emitting properties and determination of the electrons initial parameters used in the electron beam computer simulation the experimental setup is been developed. The setup consists of the high-voltage triode electrode system and allows to investigate the voltage-current characteristics of the cathode and to estimate the electron distribution of the beam on the anode surface. The anode electron distribution evaluations are processed by the measurements of the emitted X-ray focal spot on the anode by application of the CCD camera. Verification of the simulated electron beam dynamics can be obtained by application of the experimentally acquired data.
	Poster THPP129 [4.088 MB]

Paper

Title

Other Keywords

Page

MOPP003

A Compact Linac Design for an Accelerator Driven System

linac, cavity, cryomodule, lattice

52

B. Mustapha, S.V. Kutsaev, J.A. Nolen, P.N. Ostroumov
ANL, Argonne, USA

Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
A compact linac design has been developed for an Accelerator Driven System (ADS). The linac is under 150 meters in length and comprises a radio-frequency quadrupole (RFQ) and 20 superconducting modules. Three types of half-wave cavities and two types of elliptical cavities have been designed and optimized for high performance at frequencies of 162.5, 325 and 650 MHz. The lattice is being designed and optimized for operation with a peak power of 25 MW for a 25 mA – 1 GeV proton beam. The cavities RF design as well as the linac lattice will be presented along with end-to-end beam dynamics simulations for beam currents ranging from 0 to 25 mA.

MOPP034

Beam Dynamics Studies of the CLIC Drive Beam Injector

bunching, emittance, cavity, quadrupole

131

S. Sanaye Hajari, S. Döbert, H. Shaker
CERN, Geneva, Switzerland
S. Sanaye Hajari, H. Shaker
IPM, Tehran, Iran

In the Compact Linear Collider (CLIC) the RF power for the acceleration of the Main Beam is extracted from a high-current Drive Beam that runs parallel with the main linac. The beam in the Drive Beam Accelerator is phase coded. This means only every second accelerator bucket is occupied. However, a few percent of particles are captured in wrong buckets, called satellite bunches. The phase coding is done via a sub-harmonic bunching system operating at a half the acceleration frequency. The beam dynamics of the Drive Beam injector complex has been studied in detail and optimised. The model consists of a thermionic gun, the bunching system followed by some accelerating structures and a magnetic chicane. The bunching system contains three sub-harmonic bunchers, a prebuncher and a tapered travelling wave buncher all embedded in a solenoidal magnetic field. The simulation of the beam dynamics has been carried out with PARMELA with the goal of optimising the overall bunching process and in particular decreasing the satellite population and the beam loss in magnetic chicane and in transverse plane limiting the beam emittance growth.

MOPP083

Helical Waveguides for Short Wavelength Accelerators and RF Undulators

undulator, electron, FEL, radiation

248

S.V. Kuzikov, A.V. Savilov, A.A. Vikharev
IAP/RAS, Nizhny Novgorod, Russia
A.V. Savilov
NNGU, Nizhny Novgorod, Russia

The short wavelength accelerating structure can combine properties of a linear accelerator and a damping ring simultaneously. It provides acceleration of straight on-axis beam as well as cooling of this beam due to the synchrotron radiation of particles. These properties are provided by specific slow eigen mode which consists of two partial waves, TM01 and TM11. The flying RF undulator introduces a high-power short pulse, propagating in a long helically corrugated waveguide where the -1st space harmonic with negative phase velocity is responsible for particle wiggling. High group velocity allows providing long interaction of particles with RF pulse. Calculations show that RF undulator with period 5 mm, undulator parameter 0.1 is possible in 1 GW 10 ns pulse at frequency 30 GHz. The eigen mode in a helical undulator might have 0th harmonic phase velocity equal to light velocity. Such wave can be excited by relativistic drive bunch in the waveguide where witness bunch follows after the drive bunch, wiggles in wakefields, and generates X-rays at whole waveguide length. Helical waveguides can also be used in order to channel low-energy bunches in RF undulator of THz FEL.

Poster MOPP083 [2.139 MB]

MOPP095

Emittance Measurement for SPring-8 Linac Using Four Six-Electrode BPMs

emittance, linac, electron, quadrupole

279

K. Yanagida, H. Hanaki, S. Suzuki
JASRI/SPring-8, Hyogo-ken, Japan

In the SPring-8 linear accelerator (linac) six-electrode beam position monitors (BPMs) have been installed to measure second-order moments. At the end of the linac where the electron beam energy is 1 GeV four quadrupole magnets are utilized for twiss parameter matching toward the following beam transport line. Last year four six-electrode BPMs were installed at the locations of these four quadrupole magnets for an emittance measurement. The relative second-order moments were obtained changing the magnetic field strength of the quadrupole magnets, then beam sizes, emittances and twiss parameters were deduced or calculated. At this time we applied one pair of beam sizes measured by the screen monitor for a precise determination of emittances but we try to implement non-destructive measurement with no screen monitor. Before the emittance measurement a calibration with fifth-order moment correction was carried out changing beam positions at the BPM locations using upstream steering magnets (the entire calibration).

Slides MOPP095 [0.984 MB]

TUPP045

Beam Physics Challenge in FRIB Driver Linac

linac, ion, proton, acceleration

532

Y. Yamazaki, N.K. Bultman, A. Facco, Z.Q. He, M. Ikegami, M.J. Johnson, S.M. Lidia, F. Marti, G. Pozdeyev, K. Saito, J. Wei, X. Wu, Y. Zhang, Q. Zhao
FRIB, East Lansing, Michigan, USA

Funding: *Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
The Facility for Rare Isotope Beams driver linac provides CW beams of all the stable ions (from protons to uranium) with a beam power of 400 kW and a minimum beam energy of 200 MeV/u in order to produce a wide variety of rare isotopes, mainly for nuclear physics study. The low beam emittances, both transverse and longitudinal, are key performance requirements, together with beam stability. These are required for efficiently separating one isotope from another, the reason for choosing this linac configuration. Multi-charge states (five charge states for the uranium case) are accelerated for maximizing the beam current, while keeping the low emittances. The efficient acceleration of high beam currents from 0.5 MeV/u through the superconducting linac is, needless to say, one of the biggest challenges. The beam power is more than 200 times higher than existing similar SC heavy ion linac. In particular, the SC cavities are difficult to protect from heavy ion beam damage, which can be 30 times larger locally than a proton beam with the same beam power. Other challenges peculiar to the FRIB linac will be presented, together with the solutions.

TUPP063

Improvements of the LORASR Code and their Impact on Current Beam Dynamics Designs

linac, proton, DTL, quadrupole

569

R. Tiede, D. Mäder, N.F. Petry, H. Podlech, U. Ratzinger, C. Zhang
IAP, Frankfurt am Main, Germany

LORASR is a multi-particle tracking code optimized for the beam dynamics design of ‘Combined Zero Degree Structure (KONUS)’ lattices, which can benefit from an adapted input file structure and code architecture. Recent code developments focused on the implementation of tools for machine error studies and loss profile investigations, including also steering correction strategies. These tools are a stringent necessity for the design of high intensity linacs. Thus, the abilities of the present LORASR release allow performing a manifold of checks and optimizations before finalizing the layouts of KONUS-based or conventional linacs. Two representative examples are the MAX-MYRRHA Injector and the GSI FAIR Facility Proton Linac, both under development with strong participation of IAP, Frankfurt University. This paper presents the status of the LORASR code development with focus on the new features and illustrates the impact on current designs by examples taken from the above-mentioned projects.

TUPP090

Spatially Periodic RF Quadrupole LINAC

quadrupole, linac, ion, lattice

634

A.S. Plastun, A. Kolomiets
ITEP, Moscow, Russia

Spatially-periodic RF quadrupole structure is proposed as second section of front end of ion linac. It consists of conventional drift tubes and RF quadrupoles. Quadrupoles are 4-vane segments with nonzero electric potential on the longitudinal axis. Thus the accelerating electric field is formed between drift tubes and RF quadrupoles. Moreover accelerating field can be provided even inside the RF quadrupoles. It allows building structures with different focusing lattices and provides high energy gain rate.

Poster TUPP090 [7.706 MB]

TUPP110

Quasi Nonlinear Plasma Wakefield Acceleration Experiments

plasma, electron, experiment, emittance

680

S.K. Barber, G. Andonian, B.D. O'Shea, J.B. Rosenzweig, Y. Sakai, O. Williams
UCLA, Los Angeles, USA
M. Ferrario
INFN/LNF, Frascati (Roma), Italy
P. Muggli
MPI, Muenchen, Germany

It is generally agreed that the best way forward for beam driven plasma wakefield acceleration (PWFA) is in the nonlinear or blowout regime. In this regime the expulsion of the plasma electrons from the beam occupied region produces a linear transverse focusing effect and position independent longitudinal accelerating fields, which can, in principle, produce high quality beams accelerated over many meters. However, certain aspects of a linear plasma response can be advantageous, such as the possibility for resonant excitation of wakefields through the use of pulse trains. Exploiting advantages of both linear and nonlinear PWFA may be achievable through the use of low emittance and tightly focused beams with relatively small charge. In this case the beam density can be greater than that of the ambient plasma while simultaneously having a smaller total charge than the plasma electrons contained in a cubic plasma skin depth allowing for blowout in the region of the beam while simultaneously maintaining a quasi linear response in the bulk plasma. Recent experiments at BNL have been aimed at probing various salient aspects of this regime and are presented here.

THPP055

High Power Density Test of PXIE MEBT Absorber Prototype

simulation, radiation, electron, experiment

973

A.V. Shemyakin, C.M. Baffes
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
One of the goals of the PXIE program at Fermilab is to demonstrate the capability to form an arbitrary bunch pattern from an initially CW 162.5 MHz H⁻ bunch train coming out of an RFQ. The bunch-by-bunch selection will take place in the 2.1 MeV Medium Energy Beam Transport (MEBT) by directing the undesired bunches onto an absorber that needs to withstand a beam power of up to 21 kW, focused onto a spot with a ~2 mm rms radius. Two prototypes of the absorber were manufactured from molybdenum alloy TZM, and tested with a 28 keV DC electron beam up to the peak surface power density required for PXIE, 17W/mm2. Temperatures and flow parameters were measured and compared to analysis. This paper describes the absorber prototypes and key testing results.

THPP065

Acceleration of Intense Flat Beams in Periodic Lattices

emittance, DTL, space-charge, acceleration

1001

L. Groening, C. Xiao
GSI, Darmstadt, Germany
I. Hofmann
TEMF, TU Darmstadt, Darmstadt, Germany

Recently a scheme for creation of flat ion beams from linacs has been proposed to increase the efficiency of multi-turn-injection. The proof of principle experiment shall be performed at GSI in Summer 2014. Since the scheme requires charge stripping, it may be necessary to perform the round-to-flat transformation prior to acceleration to the final energy of the linac. This requires preservation of the beam flatness during acceleration along the drift tube linac. This contribution is on simulations of acceleration of flat beams subject to considerable space charge tune depression. It is shown that the flatness can be preserved if the transverse tunes are properly chosen and if mis-match along inter-tank sections is minimized along the DTL.

THPP070

Alternative Compact LEBT Design for the FAIR Injector Upgrade

ion, space-charge, rfq, emittance

1013

K. Schulte, M. Droba, S. Klaproth, O. Meusel, D. Noll, U. Ratzinger
IAP, Frankfurt am Main, Germany
S.G. Yaramyshev
GSI, Darmstadt, Germany

In order to provide high intensity and brightness of the uranium beam for the planned FAIR project, the existing High Current Injector (HSI) at GSI has to be upgraded*. A part of the upgrade program is the design and construction of a compact straight injection line into the 36 MHz Radio Frequency Quadrupole of the HSI. As an alternative to a conventional LEBT design consisting of magnetic systems such as solenoids or quadrupoles, the application of Gabor lenses has been investigated. The focusing force of the Gabor lens is created by the space charge of an electron cloud, confined by crossed magnetic and electric fields inside the lens volume. Therefore, the Gabor lens combines strong, electrostatic focusing with simultaneous space-charge compensation. In previously performed beam transport experiments at GSI a prototype Gabor lens has been tested successfully. Furthermore, the operation and performance of such a device in a real accelerator environment has been studied. In this contribution an alternative LEBT design will be discussed and an improved Gabor lens design will be presented.
*W. Barth et al., “HSI-Frontend Upgrade”, GSI Scientific Report, 2009

THPP105

Beam Dynamics Simulation for the 1 GeV High Power Proton Linac

linac, rfq, proton, simulation

1099

S.M. Polozov, V.S. Dyubkov, T. Kulevoy, A.V. Samoshin
MEPhI, Moscow, Russia
G. Kropachev, T. Kulevoy
ITEP, Moscow, Russia

Funding: This work is supported in part by the Ministry of Science and Education of Russian Federation under contract No. 14.516.11.0084
The design of high energy and high power proton linacs for accelerating driven systems (ADS) is one of the accelerator technology frontiers. Such linacs are under developing in EU, Japan, PRC but not discussed in Russia previous fifteen years. The driver linac and the breeder conceptual designs were funded by the Ministry of Science and Education of Russian Federation in 2013. The 2 MeV RFQ linac was proposed as the first accelerating section. A number of RF focusing sections types (by RF crossed lenses, modified electrode profile RFQ, axi-symmetrical RF focusing) were discussed for medium energies. The conventional modular scheme linac based on spoke-cavities and 5-cell elliptical cavities was designed for higher energies. The results of beam dynamics simulation in this linac will present.

THPP129

Carbon Field Emission Strip Cathode Electron Source

electron, cathode, simulation, vacuum

1

T.V. Bondarenko, A.I. Botyachkova, G.G. Karpinskiy, S.A. Polikhov, G.B. Sharkov
Siemens Research Center, Moscow,, Russia
A.I. Botyachkova, G.G. Karpinskiy
National Research Nuclear University (MEPhI), Moscow, Russia
A.E. Geisler, O. Heid
Siemens AG, Erlangen, Germany

Over the recent years carbon nanostructure cathodes have become promising as a high brightness electron sources with large working area for field emission structures. Measurements and calculations of a field emission strip cathode based on carbon structure and a unit for its investigation are presented in the article. For measuring of the cathode emitting properties and determination of the electrons initial parameters used in the electron beam computer simulation the experimental setup is been developed. The setup consists of the high-voltage triode electrode system and allows to investigate the voltage-current characteristics of the cathode and to estimate the electron distribution of the beam on the anode surface. The anode electron distribution evaluations are processed by the measurements of the emitted X-ray focal spot on the anode by application of the CCD camera. Verification of the simulated electron beam dynamics can be obtained by application of the experimentally acquired data.

Poster THPP129 [4.088 MB]