LINAC2014 - List of Keywords (cathode)

Paper	Title	Other Keywords	Page
MOPP012	Beam Commissioning of the SRF 704 MHz Photoemission Gun	gun, SRF, cavity, electron	70
	W. Xu, S.A. Belomestnykh, I. Ben-Zvi, D.M. Gassner, H. Hahn, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, R.F. Lambiase, G.T. McIntyre, D. Phillips, V. Ptitsyn, K.S. Smith, R. Than, D. Weiss, A. Zaltsman BNL, Upton, Long Island, New York, USA S.A. Belomestnykh, I. Ben-Zvi, V. Ptitsyn Stony Brook University, Stony Brook, USA D. Holmes AES, Medford, New York, USA
	Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. A 704 MHz superconducting RF photoemission electron gun for the R&D ERL project is under comissioning at BNL. Without a cathode insert, the SRF gun achieved its design goal: an accelerating voltage of 2 MV in CW mode. During commissioning with a copper cathode insert it reached 1.9 MV with 18% duty factor, which is limited by mulitpacting in a choke-joint cathode stalk. A new cathode stalk has been designed to eliminate multipacting in the choke-joint. This paper presents recent commissioning results, including cavity commissioning without the cathode stalk insert, first beam commissioning of the SRF gun in pulsed regime, and the design of a multipacting-free cathode stalk.

MOPP108	Vertical Electro-Polishing of Nb Nine-Cell Cavity Using Cathode with Variable-Geometry Wings	cavity, experiment, power-supply, status	307
	K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi MGH, Hyogo-ken, Japan H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe KEK, Ibaraki, Japan K. Ishimi MGI, Chiba, Japan
	Marui Galvanizing Co. Ltd. has been studying on Vertical Electro-Polishing (VEP) of Nb superconducting accelerator cavity for the mass-production and cost-reduction of Electro-Polishing (EP) process in collaboration with KEK. And we invented VEP process by a cathode with variable-geometry wings to get uniform distributions of both electric current and EP solution flow. Using this cathode, we performed various tests of VEP with Nb single-cell cavities. In this article, we will report fabrication of the first VEP facility for Nb nine-cell cavity and the VEP results using cathode with variable-geometry wings.

MOPP122	Construction of the New Amplifiers for the RIKEN-LINAC	impedance, ion, heavy-ion, controls	339
	K. Suda, E. Ikezawa, O. Kamigaito, N. Sakamoto, K. Yamada RIKEN Nishina Center, Wako, Japan Y. Touchi SHI, Tokyo, Japan
	New tetrode based amplifiers have been constructed for the RIKEN heavy-ion linac, so called RILAC[1], replacing 36-year-old amplifiers to improve their reliability as a main injector for the RIBF accelerator complex. The RILAC is a DC machine and their frequency are tunable between 18 to 40 MHz so as to be capable of accelerating heavy ions with mass-to-charge (m/q) ratios up to 28. The new rf amplifier is based on a tetrode THALES/SIEMENS RS2042SK coupled with a tetrode THALES/SIEMENS RS2012CJ with a grounded grid circuit. The maximum output power is 100 kW with a frequency ranging from 18 to 40 MHz. The amplifier was originally designed for RIKEN Ring Cyclotron. Since we have many experiences with this type of amplifier, some modification to avoid exciting the parasitic modes which might damage the cavity and/or the amplifier itself. Their construction started in April 2013 and installation was performed in January 2014. After the installation their commissioning has been successfully made. For a beam service started in this March the new amplifiers were operated without any troubles. [1]M. Odera et al., Nucl. Instrum. and Methods, 227, 187(1984).
	Poster MOPP122 [16.391 MB]

MOPP132	Development of a Micro-Pulse Electron Gun Based Upon pi-Mode Dual-Cavity	cavity, electron, gun, simulation	367
	L. Liao, Q. Gu, M. Zhang, M.H. Zhao SINAP, Shanghai, People's Republic of China
	The concept of a novel micro-pulse electron gun (MPG) based upon pi-mode dual-cavity is proposed and analyzed in this paper, and we termed it as dual-cavity micro-pulse electron gun (D-MPG) as compared to single-cavity standard MPG. From simulations, it is clear that the D-MPG is capable of yielding dozens of ampere peak currents and a few ps bunch length. Thought the mechanism for dual cavity is not fully understand, the D-MPG has demonstrate the potential to be the injectors for FEL and THz radiation facilities. Also it is a good candidate to replace the thermal cathode for industrial and medical accelerator system because of the cost-effective of the D-MPG.

TUIOA05	High-Power Industrial Accelerator ILU-14 for E-Beam and X-Ray Processing	electron, gun, controls, injection	409
	V.V. Bezuglov, A.A. Bryazgin, K.N. Chernov, B.L. Faktorovich, V.A. Gorbunov, E.N. Kokin, M.V. Korobeynikov, A.N. Lukin, I. Makarov, S.A. Maximov, A.D. Panfilov, V.M. Radchenko, E.A. Shtarklev, A.V. Sidorov, V.V. Tarnetsky, M.A. Tiunov, V.O. Tkachenko, A. YU. Vlasov, L.A. Voronin BINP SB RAS, Novosibirsk, Russia
	Growing interest to product irradiation by E-beams and X-rays calls for dedicated industrial electron accelerators. BINP has developed ILU-14 radio-frequency pulsed linear accelerator capable of providing 100 kW beam at 7.5-10 MeV. The accelerator has fast removable X-ray converter and can operate both in e-beam and X-ray processing modes. The machine utilizes a low frequency (176 MHz) 6-cells SW accelerating structure. BINP developed this machine as a turn-a-key equipment. Technical details and test results will be presented.
	Slides TUIOA05 [4.672 MB]

TUPP006	Design of Relativistic Magnetron for High Power Microwave Generation	electron, simulation, extraction, cavity	452
	R. Chandra, S.R. Ghodke, A.S. Patel, A. Sharma, S.K. Singh BARC, Mumbai, India
	A Linear Induction Accelerator based upon magnetic storage, utilising magnetic switches has been made and it is capable of providing a 400 kV diode voltage, 4 kA beam current for 100 ns pulse duration with 100 Hz repetition rate. It operates in a very high repetition rate due to the use of magnetic switches in it. The lesser shot to shot variation make this system ideal for a Relativistic Magnetron operation, where a huge dependence of output power on applied voltage and applied current is observed. A relativistic magnetron with axial extraction is analytically designed and simulated for this system. This relativistic magnetron is expected to give a power of 100 MW per pulse when operated in its full rating. The design features of this relativistic magnetron are presented here. This magnetron was designed for an output microwave frequency of 2.52 GHz. *J. Benford, ''Space Applications of High-Power Microwaves'', IEEE Trans. Plasma Sci., vol. 36, no. 3, pp. 569–581, Jun. 2008

TUPP023	Testing of the First Part of Series Production 10MW MBKs for the XFEL Project.	klystron, operation, gun, power-supply	481
	V. Vogel, L. Butkowski, A. Cherepenko, S. Choroba, J. Hartung, V.V. Kachaev, R. Wagner DESY, Hamburg, Germany
	At present more than half of 27 of 10 MW horizontal multi-beam klystrons (MBK) manufactured by two companies for the European XFEL project have been delivered to DESY. After delivery each klystron is connected to the connection module (CM), a HV oil tank with integrated HV connector, voltage and current monitors and a coaxial filament transformer, tested on the test stand and, if necessary conditioned. After this the klystrons are ready for installation in the underground linear accelerator tunnel. Two MBKs are already installed at the injector area of the XFEL. For the European XFEL project MBKs which can produce RF power of 10 MW, at RF frequency of 1.3 GHz, 1.5 ms pulse length and 10 Hz repetition rate, were chosen as RF power sources. During the incoming test the most important parameters of the MBK such as bandwidth, filament power, perveance, gain at different cathode voltage, phase stability and sensitivity to the solenoids current setting are measured and documented. In this paper we will give an overview of the test procedure, summarize the current test results and give a comparison of the most important parameters for several tubes.

TUPP030	Design of a High Average Current Electron Source for the CLIC Drive Beam Injector	gun, emittance, electron, simulation	493
	S. Döbert, N. Chritin CERN, Geneva, Switzerland B. Cadilhon, B. Cassany, J. Gardelle, K. Pepitone CEA, LE BARP cedex, France
	The drive beam injector for CLIC needs to deliver a 4.2 A electron beam for a duration of 140 μs with a repetition rate of 50 Hz. The shot to shot and flat top current stability has to be better than 0.1% to guarantee the beam stability required for CLIC. Based on the experience with the CTF3 injector a thermionic high voltage gun with a gridded cathode has been designed together with a sub-harmonic bunching system to achieve these requirements. The grid will allow controlling the current and eventually feedback on the flattop shape. The gun will operate at 140 kV and an emittance of 14 mm mrad can be obtained. The paper describes the design approach and the results of the systematic electromagnetic simulations to optimize the gun. Care was taken during the mechanical design of the gun to obtain a modular design allowing adjusting for different beam currents and cathode sizes.

TUPP070	Status and Recent Modifications to 324-MHz RF Source in J-PARC LINAC	klystron, linac, operation, high-voltage	587
	M. Kawamura, Y. Fukui, K. Futatsukawa, F. Naito KEK, Ibaraki, Japan E. Chishiro, K. Hasegawa, F. Sato, S. Shinozaki JAEA/J-PARC, Tokai-mura, Japan T. Hori JAEA, Ibaraki-ken, Japan
	This paper describes the present status of and the recent modifications to the 324-MHz RF source in the J-PARC linac. The recovery from the Great East Japan Earthquake Disaster, the status of the 324-MHz klystrons, the failure of 3 high-voltage transformers (HVTRs), and the discharge suppression for the anode-modulators are described.
	Poster TUPP070 [0.660 MB]

TUPP078	High Gain FEL with a Micro-bunch Structured Beam by the Transverse-Longitudinal Phase Space Rotation	FEL, cavity, radiation, electron	607
	M. Kuriki, Y. Seimiya HU/AdSM, Higashi-Hiroshima, Japan H. Hayano, K. Ohmi KEK, Ibaraki, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan R. Kato ISIR, Osaka, Japan
	FEL is one of the ideal radiation source over the wide range of wavelength region with a high brightness and a high coherence. Many methods to improve FEL gain has been proposed by introducing an active modulation on the bunch charge distribution. The transverse-longitudinal phase-space rotation is one of the promising method to realize the density modulation as the micro-bunch structure. Initially, a beam density modulation in the transverse direction made by a mechanical slit, is properly transformed into the density modulation in the longitudinal direction by the phase-space rotation. That results the longitudinal micro-bunch structure. The micro-bunch structure made with this method has a large tunability by changing the slit geometry, the beam line design, and the beam dynamics tuning. A compact FEL facility based on this method is proposed.
	Poster TUPP078 [0.594 MB]

TUPP101	Vertical Electro-Polishing of Nb Single-Cell Cavity Using Cathode with Variable-Geometry Wings and Its Results of Vertical Test	cavity, power-supply, target, experiment	662
	K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi MGH, Hyogo-ken, Japan P. Carbonnier, F. Éozénou, C. Servouin CEA/DSM/IRFU, France H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe KEK, Ibaraki, Japan K. Ishimi MGI, Chiba, Japan C. Madec, L. Maurice CEA/IRFU, Gif-sur-Yvette, France
	Marui Galvanizing Co. Ltd. has been studying Vertical Electro-Polishing (VEP) on Nb superconducting accelerator cavity with the goal of mass-production and cost-reduction of Electro-Polishing (EP) process in collaboration with KEK and CEA Saclay. And we invented variable-geometry wings cathode for VEP process to get uniform distributions of both electric current and EP solution flow. Using this cathode, we performed various tests of VEP with Nb single-cell cavities. In this article, we will report the results of vertical test of Nb single-cell cavity which is VEP’ed by cathode with variable-geometry wings.

TUPP112	Study of a C-Band TW Electron Gun for SwissFEL	gun, emittance, klystron, cavity	686
	M. Schaer, A. Citterio, P. Craievich, L. Stingelin, R. Zennaro PSI, Villigen PSI, Switzerland
	For a future upgrade of the SwissFEL facility, the replacement of the S-band standing wave electron gun by a C-band standing wave, or traveling wave gun is investigated. The full model of the C-band TW gun is calculated with HFSS and is characterized by an almost vanishing group velocity in the first cell to increase the field at the cathode. ASTRA simulations predict that in the case of the C-band SW gun, a two times higher peak current of ~ 40 A can be generated while still preserving the low slice emittance of ~ 0.2 um at 200 pC, due to the higher electric field on cathode and improved magnetic focusing. This would help to halve the overall beam compression factor, relax the phase stability requirement of S- and X-band systems operated off-crest for compression and decrease the gain curve in theμbunch instability. Compared to the SW gun, a TW gun provides a more homogeneous acceleration and does not require any circulator. In this study, the preliminary RF design and beam performance of a C-band TW gun is presented and compared to a pure C-band SW gun presently under design at Paul Scherrer Institut and to the operating S-band SW gun.

TUPP116	Status of the FERMI II RF Gun at Sincrotrone Trieste	gun, coupling, emittance, dipole	692
	L. Faillace, R.B. Agustsson, P. Frigola, A. Verma RadiaBeam, Santa Monica, California, USA
	Radiabeam Technologies, in collaboration with UCLA, developed a high gradient normal conducting radio frequency (NCRF) 1.6 cell photoinjector system, termed the Fermi Gun II, for the Sincrotrone Trieste (ST) facility. The RF gun has been already in full operation since mid-2013 as the injector for the ST FEL. We report here the current status of the photoinjector system.

TUPP123	Design of Novel RF Sources to Reduce the Beam Pace-Charge Effects	cavity, electron, klystron, space-charge	712
	M. Dal Forno, A. Jensen, R.D. Ruth, S.G. Tantawi SLAC, Menlo Park, California, USA
	Funding: DOE Traditional RF sources, such as Klystrons, TWT require a magnet (such as a solenoid) in order to maintain the electron beam focusing, compensating the particle repulsion caused by space charge effects. We designed a novel RF source with an alternative approach that reduces beam space charge problems. This paper shows the design of the device, with a new formulation of the Child’s Law, and the mode-beam stability analysis. The electron beam interaction with the cavity fields has been analyzed by means of particle tracking software in order to evaluate the beam bunching and the beam dynamics.
	Poster TUPP123 [0.172 MB]

WEIOA04	Phase Locked Magnetrons for Accelerators	injection, controls, cavity, electron	751
	A.C. Dexter Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	Magnetrons offer lower capital costs and higher efficiencies than klystrons, however are natural oscillators rather than amplifiers. This paper reviews techniques and issues for applying high efficiency L band magnetrons to long pulse, high intensity proton linacs. Reference is made to a proof of principle experiment whereby the phase of an SRF cavity was accurately controlled when energised by a magnetron.
	Slides WEIOA04 [1.224 MB]

THPP029	Electropolishing Simulation on Full Scale Radio Frequency Elliptical Structures	cavity, simulation, niobium, radio-frequency	898
	L.M.A. Ferreira CERN, Geneva, Switzerland H. Rana, J.A. Shirra Loughborough University, Leicestershre, United Kingdom
	This paper describes a methodology to simulate the electropolishing of a full scale radio frequency (RF) accelerating elliptical cavity through data acquired by means of a rotating disc electrode (RDE) in a three electrode set-up. The method combines laboratorial data from the RDE with computational simulation performed with Comsol Multiphysics® either for the primary and secondary current distribution as well as to account for the local effect of hydrodynamic perturbations. The results are compared with experimental data from the electropolishing of niobium 704 MHz and five cell cavity from the Superconducting Proton Linear Accelerator (SPL) R&D project at CERN.
	Poster THPP029 [0.177 MB]

THPP062	BERLinPro SRF Gun Notch Filter Investigations	gun, cavity, SRF, resonance	995
	E.N. Zaplatin FZJ, Jülich, Germany J. Knobloch, A. Neumann HZB, Berlin, Germany
	BERLinPro is an approved ERL project to demonstrate energy recovery at 100 mA beam current by pertaining a high quality beam. These goals place stringent requirements on the SRF cavity (1300 MHz, β=1) for the photoinjector which has to deliver a small emittance 100 mA beam with at least 1.8 MeV kinetic energy while limited by fundamental power coupler performance to about 230 kW forward power. The RF and beam dynamics gun cavity features 1.4 λ/2 cell resonator. To protect a cathode housing from RF power propagation from the cavity cells and to reduce its component heating a high-frequency notch filter was investigated. We present results of different schemes of choke cell combinations to optimize filter parameters. The goal for the filter design was the RF power attenuation better than -30 dB in the wide frequency range.

THPP098	Vertical Electropolishing of Nb Coupon Cavity and Surface Study of the Coupon Samples	cavity, experiment, target, superconducting-RF	1080
	V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi MGH, Hyogo-ken, Japan H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe KEK, Ibaraki, Japan K. Ishimi MGI, Chiba, Japan
	We have been carrying out vertical electropolishing (VEP) of 1.3 GHz Nb cavities for the ILC for 2 years. In this article we present VEP of a single cell Nb coupon cavity containing 6 Nb disk type coupons located at beam pipes, irises and equator positions of the cavity. VEP experiments were performed using our special ninja-cathode newly developed and a straight rod cathode in order to observe and compare the homogeneity of electropolishing (EP) and surface quality on the entire surface of the single cell cavity. EP current was measured for the individual coupons under different EP conditions in order to study the EP phenomenon on the different positions of the cavity. The surfaces of the coupons were analyzed by x-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX). This article describes VEP and surface analysis results in detail.

THPP114	The SwissFEL RF Gun: Manufacturing and Proof of Precision by Field Profile Measurements	gun, electron, coupling, vacuum	1117
	U. Ellenberger, H. Blumer, M. Kleeb, L. Paly, M. Probst Paul Scherrer Institute, Villigen PSI, Switzerland M. Bopp, A. Citterio, H. Fitze, J.-Y. Raguin, A. Scherer, L. Stingelin PSI, Villigen PSI, Switzerland
	The high brightness electron source for SwissFEL is an in-house built 2.6 cell normal-conducting RF gun which is scaled to the RF frequency of 2'998.8 MHz. The RF gun is capable of operating at 100 Hz repetition rate and produces electron bunches at the exit of the RF gun of an energy of 7 MeV. Key features of the RF gun are described and how they have been implemented in the manufacturing process. RF field measurements of the RF gun are presented to account for the mechanical precision reached after manufacturing. The RF gun has been thoroughly tested in the SwissFEL injector test facility.

THPP129	Carbon Field Emission Strip Cathode Electron Source	electron, simulation, vacuum, focusing	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

MOPP012

Beam Commissioning of the SRF 704 MHz Photoemission Gun

gun, SRF, cavity, electron

70

W. Xu, S.A. Belomestnykh, I. Ben-Zvi, D.M. Gassner, H. Hahn, J.P. Jamilkowski, P. Kankiya, D. Kayran, N. Laloudakis, R.F. Lambiase, G.T. McIntyre, D. Phillips, V. Ptitsyn, K.S. Smith, R. Than, D. Weiss, A. Zaltsman
BNL, Upton, Long Island, New York, USA
S.A. Belomestnykh, I. Ben-Zvi, V. Ptitsyn
Stony Brook University, Stony Brook, USA
D. Holmes
AES, Medford, New York, USA

Funding: This work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
A 704 MHz superconducting RF photoemission electron gun for the R&D ERL project is under comissioning at BNL. Without a cathode insert, the SRF gun achieved its design goal: an accelerating voltage of 2 MV in CW mode. During commissioning with a copper cathode insert it reached 1.9 MV with 18% duty factor, which is limited by mulitpacting in a choke-joint cathode stalk. A new cathode stalk has been designed to eliminate multipacting in the choke-joint. This paper presents recent commissioning results, including cavity commissioning without the cathode stalk insert, first beam commissioning of the SRF gun in pulsed regime, and the design of a multipacting-free cathode stalk.

MOPP108

Vertical Electro-Polishing of Nb Nine-Cell Cavity Using Cathode with Variable-Geometry Wings

cavity, experiment, power-supply, status

307

K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi
MGH, Hyogo-ken, Japan
H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
KEK, Ibaraki, Japan
K. Ishimi
MGI, Chiba, Japan

Marui Galvanizing Co. Ltd. has been studying on Vertical Electro-Polishing (VEP) of Nb superconducting accelerator cavity for the mass-production and cost-reduction of Electro-Polishing (EP) process in collaboration with KEK. And we invented VEP process by a cathode with variable-geometry wings to get uniform distributions of both electric current and EP solution flow. Using this cathode, we performed various tests of VEP with Nb single-cell cavities. In this article, we will report fabrication of the first VEP facility for Nb nine-cell cavity and the VEP results using cathode with variable-geometry wings.

MOPP122

Construction of the New Amplifiers for the RIKEN-LINAC

impedance, ion, heavy-ion, controls

339

K. Suda, E. Ikezawa, O. Kamigaito, N. Sakamoto, K. Yamada
RIKEN Nishina Center, Wako, Japan
Y. Touchi
SHI, Tokyo, Japan

New tetrode based amplifiers have been constructed for the RIKEN heavy-ion linac, so called RILAC[1], replacing 36-year-old amplifiers to improve their reliability as a main injector for the RIBF accelerator complex. The RILAC is a DC machine and their frequency are tunable between 18 to 40 MHz so as to be capable of accelerating heavy ions with mass-to-charge (m/q) ratios up to 28. The new rf amplifier is based on a tetrode THALES/SIEMENS RS2042SK coupled with a tetrode THALES/SIEMENS RS2012CJ with a grounded grid circuit. The maximum output power is 100 kW with a frequency ranging from 18 to 40 MHz. The amplifier was originally designed for RIKEN Ring Cyclotron. Since we have many experiences with this type of amplifier, some modification to avoid exciting the parasitic modes which might damage the cavity and/or the amplifier itself. Their construction started in April 2013 and installation was performed in January 2014. After the installation their commissioning has been successfully made. For a beam service started in this March the new amplifiers were operated without any troubles. [1]M. Odera et al., Nucl. Instrum. and Methods, 227, 187(1984).

Poster MOPP122 [16.391 MB]

MOPP132

Development of a Micro-Pulse Electron Gun Based Upon pi-Mode Dual-Cavity

cavity, electron, gun, simulation

367

L. Liao, Q. Gu, M. Zhang, M.H. Zhao
SINAP, Shanghai, People's Republic of China

The concept of a novel micro-pulse electron gun (MPG) based upon pi-mode dual-cavity is proposed and analyzed in this paper, and we termed it as dual-cavity micro-pulse electron gun (D-MPG) as compared to single-cavity standard MPG. From simulations, it is clear that the D-MPG is capable of yielding dozens of ampere peak currents and a few ps bunch length. Thought the mechanism for dual cavity is not fully understand, the D-MPG has demonstrate the potential to be the injectors for FEL and THz radiation facilities. Also it is a good candidate to replace the thermal cathode for industrial and medical accelerator system because of the cost-effective of the D-MPG.

TUIOA05

High-Power Industrial Accelerator ILU-14 for E-Beam and X-Ray Processing

electron, gun, controls, injection

409

V.V. Bezuglov, A.A. Bryazgin, K.N. Chernov, B.L. Faktorovich, V.A. Gorbunov, E.N. Kokin, M.V. Korobeynikov, A.N. Lukin, I. Makarov, S.A. Maximov, A.D. Panfilov, V.M. Radchenko, E.A. Shtarklev, A.V. Sidorov, V.V. Tarnetsky, M.A. Tiunov, V.O. Tkachenko, A. YU. Vlasov, L.A. Voronin
BINP SB RAS, Novosibirsk, Russia

Growing interest to product irradiation by E-beams and X-rays calls for dedicated industrial electron accelerators. BINP has developed ILU-14 radio-frequency pulsed linear accelerator capable of providing 100 kW beam at 7.5-10 MeV. The accelerator has fast removable X-ray converter and can operate both in e-beam and X-ray processing modes. The machine utilizes a low frequency (176 MHz) 6-cells SW accelerating structure. BINP developed this machine as a turn-a-key equipment. Technical details and test results will be presented.

Slides TUIOA05 [4.672 MB]

TUPP006

Design of Relativistic Magnetron for High Power Microwave Generation

electron, simulation, extraction, cavity

452

R. Chandra, S.R. Ghodke, A.S. Patel, A. Sharma, S.K. Singh
BARC, Mumbai, India

A Linear Induction Accelerator based upon magnetic storage, utilising magnetic switches has been made and it is capable of providing a 400 kV diode voltage, 4 kA beam current for 100 ns pulse duration with 100 Hz repetition rate. It operates in a very high repetition rate due to the use of magnetic switches in it. The lesser shot to shot variation make this system ideal for a Relativistic Magnetron operation, where a huge dependence of output power on applied voltage and applied current is observed. A relativistic magnetron with axial extraction is analytically designed and simulated for this system. This relativistic magnetron is expected to give a power of 100 MW per pulse when operated in its full rating. The design features of this relativistic magnetron are presented here. This magnetron was designed for an output microwave frequency of 2.52 GHz.
*J. Benford, ''Space Applications of High-Power Microwaves'', IEEE Trans. Plasma Sci., vol. 36, no. 3, pp. 569–581, Jun. 2008

TUPP023

Testing of the First Part of Series Production 10MW MBKs for the XFEL Project.

klystron, operation, gun, power-supply

481

V. Vogel, L. Butkowski, A. Cherepenko, S. Choroba, J. Hartung, V.V. Kachaev, R. Wagner
DESY, Hamburg, Germany

At present more than half of 27 of 10 MW horizontal multi-beam klystrons (MBK) manufactured by two companies for the European XFEL project have been delivered to DESY. After delivery each klystron is connected to the connection module (CM), a HV oil tank with integrated HV connector, voltage and current monitors and a coaxial filament transformer, tested on the test stand and, if necessary conditioned. After this the klystrons are ready for installation in the underground linear accelerator tunnel. Two MBKs are already installed at the injector area of the XFEL. For the European XFEL project MBKs which can produce RF power of 10 MW, at RF frequency of 1.3 GHz, 1.5 ms pulse length and 10 Hz repetition rate, were chosen as RF power sources. During the incoming test the most important parameters of the MBK such as bandwidth, filament power, perveance, gain at different cathode voltage, phase stability and sensitivity to the solenoids current setting are measured and documented. In this paper we will give an overview of the test procedure, summarize the current test results and give a comparison of the most important parameters for several tubes.

TUPP030

Design of a High Average Current Electron Source for the CLIC Drive Beam Injector

gun, emittance, electron, simulation

493

S. Döbert, N. Chritin
CERN, Geneva, Switzerland
B. Cadilhon, B. Cassany, J. Gardelle, K. Pepitone
CEA, LE BARP cedex, France

The drive beam injector for CLIC needs to deliver a 4.2 A electron beam for a duration of 140 μs with a repetition rate of 50 Hz. The shot to shot and flat top current stability has to be better than 0.1% to guarantee the beam stability required for CLIC. Based on the experience with the CTF3 injector a thermionic high voltage gun with a gridded cathode has been designed together with a sub-harmonic bunching system to achieve these requirements. The grid will allow controlling the current and eventually feedback on the flattop shape. The gun will operate at 140 kV and an emittance of 14 mm mrad can be obtained. The paper describes the design approach and the results of the systematic electromagnetic simulations to optimize the gun. Care was taken during the mechanical design of the gun to obtain a modular design allowing adjusting for different beam currents and cathode sizes.

TUPP070

Status and Recent Modifications to 324-MHz RF Source in J-PARC LINAC

klystron, linac, operation, high-voltage

587

M. Kawamura, Y. Fukui, K. Futatsukawa, F. Naito
KEK, Ibaraki, Japan
E. Chishiro, K. Hasegawa, F. Sato, S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan
T. Hori
JAEA, Ibaraki-ken, Japan

This paper describes the present status of and the recent modifications to the 324-MHz RF source in the J-PARC linac. The recovery from the Great East Japan Earthquake Disaster, the status of the 324-MHz klystrons, the failure of 3 high-voltage transformers (HVTRs), and the discharge suppression for the anode-modulators are described.

Poster TUPP070 [0.660 MB]

TUPP078

High Gain FEL with a Micro-bunch Structured Beam by the Transverse-Longitudinal Phase Space Rotation

FEL, cavity, radiation, electron

607

M. Kuriki, Y. Seimiya
HU/AdSM, Higashi-Hiroshima, Japan
H. Hayano, K. Ohmi
KEK, Ibaraki, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
R. Kato
ISIR, Osaka, Japan

FEL is one of the ideal radiation source over the wide range of wavelength region with a high brightness and a high coherence. Many methods to improve FEL gain has been proposed by introducing an active modulation on the bunch charge distribution. The transverse-longitudinal phase-space rotation is one of the promising method to realize the density modulation as the micro-bunch structure. Initially, a beam density modulation in the transverse direction made by a mechanical slit, is properly transformed into the density modulation in the longitudinal direction by the phase-space rotation. That results the longitudinal micro-bunch structure. The micro-bunch structure made with this method has a large tunability by changing the slit geometry, the beam line design, and the beam dynamics tuning. A compact FEL facility based on this method is proposed.

Poster TUPP078 [0.594 MB]

TUPP101

Vertical Electro-Polishing of Nb Single-Cell Cavity Using Cathode with Variable-Geometry Wings and Its Results of Vertical Test

cavity, power-supply, target, experiment

662

K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi
MGH, Hyogo-ken, Japan
P. Carbonnier, F. Éozénou, C. Servouin
CEA/DSM/IRFU, France
H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
KEK, Ibaraki, Japan
K. Ishimi
MGI, Chiba, Japan
C. Madec, L. Maurice
CEA/IRFU, Gif-sur-Yvette, France

Marui Galvanizing Co. Ltd. has been studying Vertical Electro-Polishing (VEP) on Nb superconducting accelerator cavity with the goal of mass-production and cost-reduction of Electro-Polishing (EP) process in collaboration with KEK and CEA Saclay. And we invented variable-geometry wings cathode for VEP process to get uniform distributions of both electric current and EP solution flow. Using this cathode, we performed various tests of VEP with Nb single-cell cavities. In this article, we will report the results of vertical test of Nb single-cell cavity which is VEP’ed by cathode with variable-geometry wings.

TUPP112

Study of a C-Band TW Electron Gun for SwissFEL

gun, emittance, klystron, cavity

686

M. Schaer, A. Citterio, P. Craievich, L. Stingelin, R. Zennaro
PSI, Villigen PSI, Switzerland

For a future upgrade of the SwissFEL facility, the replacement of the S-band standing wave electron gun by a C-band standing wave, or traveling wave gun is investigated. The full model of the C-band TW gun is calculated with HFSS and is characterized by an almost vanishing group velocity in the first cell to increase the field at the cathode. ASTRA simulations predict that in the case of the C-band SW gun, a two times higher peak current of ~ 40 A can be generated while still preserving the low slice emittance of ~ 0.2 um at 200 pC, due to the higher electric field on cathode and improved magnetic focusing. This would help to halve the overall beam compression factor, relax the phase stability requirement of S- and X-band systems operated off-crest for compression and decrease the gain curve in theμbunch instability. Compared to the SW gun, a TW gun provides a more homogeneous acceleration and does not require any circulator. In this study, the preliminary RF design and beam performance of a C-band TW gun is presented and compared to a pure C-band SW gun presently under design at Paul Scherrer Institut and to the operating S-band SW gun.

TUPP116

Status of the FERMI II RF Gun at Sincrotrone Trieste

gun, coupling, emittance, dipole

692

L. Faillace, R.B. Agustsson, P. Frigola, A. Verma
RadiaBeam, Santa Monica, California, USA

Radiabeam Technologies, in collaboration with UCLA, developed a high gradient normal conducting radio frequency (NCRF) 1.6 cell photoinjector system, termed the Fermi Gun II, for the Sincrotrone Trieste (ST) facility. The RF gun has been already in full operation since mid-2013 as the injector for the ST FEL. We report here the current status of the photoinjector system.

TUPP123

Design of Novel RF Sources to Reduce the Beam Pace-Charge Effects

cavity, electron, klystron, space-charge

712

M. Dal Forno, A. Jensen, R.D. Ruth, S.G. Tantawi
SLAC, Menlo Park, California, USA

Funding: DOE
Traditional RF sources, such as Klystrons, TWT require a magnet (such as a solenoid) in order to maintain the electron beam focusing, compensating the particle repulsion caused by space charge effects. We designed a novel RF source with an alternative approach that reduces beam space charge problems. This paper shows the design of the device, with a new formulation of the Child’s Law, and the mode-beam stability analysis. The electron beam interaction with the cavity fields has been analyzed by means of particle tracking software in order to evaluate the beam bunching and the beam dynamics.

Poster TUPP123 [0.172 MB]

WEIOA04

Phase Locked Magnetrons for Accelerators

injection, controls, cavity, electron

751

A.C. Dexter
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

Magnetrons offer lower capital costs and higher efficiencies than klystrons, however are natural oscillators rather than amplifiers. This paper reviews techniques and issues for applying high efficiency L band magnetrons to long pulse, high intensity proton linacs. Reference is made to a proof of principle experiment whereby the phase of an SRF cavity was accurately controlled when energised by a magnetron.

Slides WEIOA04 [1.224 MB]

THPP029

Electropolishing Simulation on Full Scale Radio Frequency Elliptical Structures

cavity, simulation, niobium, radio-frequency

898

L.M.A. Ferreira
CERN, Geneva, Switzerland
H. Rana, J.A. Shirra
Loughborough University, Leicestershre, United Kingdom

This paper describes a methodology to simulate the electropolishing of a full scale radio frequency (RF) accelerating elliptical cavity through data acquired by means of a rotating disc electrode (RDE) in a three electrode set-up. The method combines laboratorial data from the RDE with computational simulation performed with Comsol Multiphysics® either for the primary and secondary current distribution as well as to account for the local effect of hydrodynamic perturbations. The results are compared with experimental data from the electropolishing of niobium 704 MHz and five cell cavity from the Superconducting Proton Linear Accelerator (SPL) R&D project at CERN.

Poster THPP029 [0.177 MB]

THPP062

BERLinPro SRF Gun Notch Filter Investigations

gun, cavity, SRF, resonance

995

E.N. Zaplatin
FZJ, Jülich, Germany
J. Knobloch, A. Neumann
HZB, Berlin, Germany

BERLinPro is an approved ERL project to demonstrate energy recovery at 100 mA beam current by pertaining a high quality beam. These goals place stringent requirements on the SRF cavity (1300 MHz, β=1) for the photoinjector which has to deliver a small emittance 100 mA beam with at least 1.8 MeV kinetic energy while limited by fundamental power coupler performance to about 230 kW forward power. The RF and beam dynamics gun cavity features 1.4 λ/2 cell resonator. To protect a cathode housing from RF power propagation from the cavity cells and to reduce its component heating a high-frequency notch filter was investigated. We present results of different schemes of choke cell combinations to optimize filter parameters. The goal for the filter design was the RF power attenuation better than -30 dB in the wide frequency range.

THPP098

Vertical Electropolishing of Nb Coupon Cavity and Surface Study of the Coupon Samples

cavity, experiment, target, superconducting-RF

1080

V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi
MGH, Hyogo-ken, Japan
H. Hayano, S. Kato, H. Monjushiro, T. Saeki, M. Sawabe
KEK, Ibaraki, Japan
K. Ishimi
MGI, Chiba, Japan

We have been carrying out vertical electropolishing (VEP) of 1.3 GHz Nb cavities for the ILC for 2 years. In this article we present VEP of a single cell Nb coupon cavity containing 6 Nb disk type coupons located at beam pipes, irises and equator positions of the cavity. VEP experiments were performed using our special ninja-cathode newly developed and a straight rod cathode in order to observe and compare the homogeneity of electropolishing (EP) and surface quality on the entire surface of the single cell cavity. EP current was measured for the individual coupons under different EP conditions in order to study the EP phenomenon on the different positions of the cavity. The surfaces of the coupons were analyzed by x-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX). This article describes VEP and surface analysis results in detail.

THPP114

The SwissFEL RF Gun: Manufacturing and Proof of Precision by Field Profile Measurements

gun, electron, coupling, vacuum

1117

U. Ellenberger, H. Blumer, M. Kleeb, L. Paly, M. Probst
Paul Scherrer Institute, Villigen PSI, Switzerland
M. Bopp, A. Citterio, H. Fitze, J.-Y. Raguin, A. Scherer, L. Stingelin
PSI, Villigen PSI, Switzerland

The high brightness electron source for SwissFEL is an in-house built 2.6 cell normal-conducting RF gun which is scaled to the RF frequency of 2'998.8 MHz. The RF gun is capable of operating at 100 Hz repetition rate and produces electron bunches at the exit of the RF gun of an energy of 7 MeV. Key features of the RF gun are described and how they have been implemented in the manufacturing process. RF field measurements of the RF gun are presented to account for the mechanical precision reached after manufacturing. The RF gun has been thoroughly tested in the SwissFEL injector test facility.

THPP129

Carbon Field Emission Strip Cathode Electron Source

electron, simulation, vacuum, focusing

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]