LINAC2012 - List of Keywords (radiation)

Paper	Title	Other Keywords	Page
SUPB035	RF Photoinjector and Radiating Structure for High-power THz Radiation Source	coupling, electron, vacuum, impedance	86
	S.M. Polozov, T.V. Bondarenko MEPhI, Moscow, Russia Y.A. Bashmakov LPI, Moscow, Russia
	Sources of high-power electromagnetic radiation in THz band are becoming promising as a new method of a low activation introscopy. Research and development of accelerating RF photoinjector and radiating system for THz radiation source are reported. The photoinjector is based on disk loaded waveguide (DLW). Two different designs of accelerating structures were modeled: widespread 1.6 cell of DLW structure and travelling wave resonator structure. The resonant models of these structures and the structures with power ports were designed. Electrodynamics characteristics and electric field distribution for all models were acquired. Results of picoseconds photoelectron beam dynamics in modeled structures are reported. Design of decelerating structures exciting Cherenkov radiation are based on corrugated metal channel and metal channel coated with dielectric. Analysis of radiation intensity and frequency band are presented.

MOPB051	Changing Attitude to Radiation Hazards and Consequent Opportunities for LINAC Applications	linac, electron, background, status	288
	Y. Socol Falcon Analytics, Netanya, Israel
	High-energy LINACs unavoidably yield ionizing radiation. This fact makes them subject to strict regulations and considerably limits applications. During the last two decades the attitude to ionizing radiation hazards seems to become more balanced, as opposed to "radiophobia" of the Cold-War era. Scientifically, the linear no-threshold (LNT) model of radiation damage is more and more questioned. Moreover, the hypotheses of radiation hormesis - beneficial effect of low-dose radiation - is studied. While this scientific debate has not yet given fruit regarding radiation regulation and policy, we may expect this in near to middle term. Namely, the ALARA (as low as reasonably achievable) demand is anticipated to be substituted by some tolerance level, which in turn is anticipated to be very high according to the present standards. The presentation will review the present status of the radiation-hazard debate, and outline anticipated opportunities for LINAC applications, like compact designs and wider industrial outreach.

MOPB096	Beam Loss Mitigation in J-PARC Linac after the Tohoku Earthquake	linac, multipactoring, beam-losses, beam-transport	401
	M. Ikegami, Z. Fang, K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan Y. Liu KEK/JAEA, Ibaraki-Ken, Japan T. Maruta, A. Miura, J. Tamura, G.H. Wei JAEA/J-PARC, Tokai-mura, Japan H. Sako JAEA, Ibaraki-ken, Japan
	The beam operation of J-PARC linac was interrupted by the Tohoku earthquake in March 2011. After significant effort for its restoration, we have resumed the beam operation of J-PARC linac in December 2011. After resumption of beam operation, we have been suffering from beam losses which were not observed before the earthquake. Tackling with the beam loss issues, we have been reached the comparable beam power for user operation to the one before the earthquake. In this paper, we present the experience in the beam start-up tuning after the earthquake with emphasis on the beam loss mitigation efforts.

TUPB014	Comparative Design of Single Pass, Photo-cathode RF-LINAC FEL for the THz Frequency Range: Self Amplification vs. Enhanced Super-radiance	FEL, electron, linac, wiggler	507
	Yu. Lurie, Y. Pinhasi Ariel University Center of Samaria, Faculty of Engineering, Ariel, Israel
	Self amplified spontaneous emission and enhanced super-radiance are discussed and compared as possible configurations in the construction of a single-pass, photo-cathode RF-LINAC FEL source for THz radiation, being developed in Ariel University Center of Samaria. Numerical simulations carried out using 3D, space-frequency approach demonstrate the charge squared dependence of the radiation power in both cases, the characteristic typical to super-radiant emission. The comparison reveals a high efficiency of an enhanced super-radiance FEL, which however can only be achieved with ultra-short (the radiation wavelength long or shorter) drive electron beam bunches at a proper energy chirping.

TUPB015	Warm Beamlines and Infrastructure in the European XFEL	linac, shielding, diagnostics, klystron	510
	M. Hüning DESY, Hamburg, Germany
	The European XFEL is driven by a superconducting linear accelerator. In the main accelerator tunnel the accelerator modules will be suspended from the tunnel ceiling. The warm sections like bunch compressors will be installed on girders supported from the floor. The accelerator infrastructure like klystrons and electronic racks will be installed in the accelerator tunnel in close proximity to the electron beamline.

TUPB053	Main Coupler Design for Project X	vacuum, cavity, linac, cryomodule	594
	S. Kazakov, S. Cheban, T.N. Khabiboulline, M. Kramp, Y. Orlov, V. Poloubotko, O. Pronitchev, V.P. Yakovlev Fermilab, Batavia, USA M.S. Champion ORNL, Oak Ridge, Tennessee, USA
	A multi-megawatt proton/H⁻ source, Project X, is under development at Fermi National Accelerator Laboratory. Main element of it is a 3 GeV superconducting proton linac which includes 5 families of superconducting cavities of three frequencies: 162.5, 325 and 650 MHz. Scope of this paper is the development of power couplers for 325 and 650 MHz at FNAL. Upgraded version of the accelerator will require two types of couplers, which reliably can operate at CW power level ~25 kW at 325 MHz and ~100 kW at 650 MHz respectively. In this paper we are describing the current design of these devices.

TUPB101	Beam Loss Occurred at DTL Cavity in J-PARC Linac	DTL, cavity, linac, drift-tube-linac	696
	A. Miura, K. Hirano, T. Ito, T. Maruta JAEA/J-PARC, Tokai-mura, Japan M. Ikegami J-PARC, KEK & JAEA, Ibaraki-ken, Japan T. Miyao, F. Naito, K. Nanmo KEK, Ibaraki, Japan
	The beam operation of J-PARC linac was suspended until December 2011 due to the damage by the Tohoku earthquake in March 2011. After resumed the operations, we measured the residual radiation along with the beam line during a short interval. Because the higher residual radiation was detected at the surface of drift tube linac (DTL) cavity by radiation survey, we installed the scintillation beam loss monitors (BLM) at the points where the higher radiation was detected to understand the cause of the radiation. Even the DTL section is low energy part of the linac, fine structure of the beam loss was observed by the scintillation BLM. And we measured the beam loss occurred at the DTL with the parameters of beam orbit and cavity settings. Also, the BLM is employed for the linac tuning. In this paper, the result of the radiation measurement and beam loss signals obtained by the scintillation BLMs are presented.

TH3A04	Plasmas, Dielectrics and the Ultrafast: First Science and Operational Experience at FACET	plasma, electron, linac, acceleration	802
	C.I. Clarke, E. Adli, S. Corde, F.-J. Decker, R.J. England, R.A. Erickson, A.S. Fisher, S.J. Gessner, C. Hast, M.J. Hogan, S.Z. Li, N. Lipkowitz, M.D. Litos, Y. Nosochkov, J.T. Seeman, J. Sheppard, I. Tudosa, G.R. White, U. Wienands, M. Woodley, Z. Wu, G. Yocky SLAC, Menlo Park, California, USA C.E. Clayton, C. Joshi, W. Lu, K.A. Marsh, N. Vafaei UCLA, Los Angeles, California, USA
	Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515. FACET (Facility for Advanced Accelerator and Experimental Tests) is an accelerator R&D test facility that has been recently constructed at SLAC National Accelerator Laboratory. The facility provides 20 GeV, 3 nC electron beams, short (20 um) bunches and small (20 um wide) spot sizes, producing uniquely high power beams. FACET supports studies from many fields but in particular those of Plasma Wakefield Acceleration and Dielectric Wakefield Acceleration. FACET is also a source of THz radiation for material studies. We present the FACET design, initial operating experience and first science from the facility.
	Slides TH3A04 [3.091 MB]

THPB021	Recovery Efforts from the Tohoku Earthquake and Energy Upgrade Preparation of the Beam Transport from the J-PARC Linac to the 3-GeV Synchrotron	linac, beam-transport, synchrotron, vacuum	891
	J. Tamura, H. Ao, H. Asano, T. Morishita, N. Ouchi JAEA/J-PARC, Tokai-mura, Japan Y. Sawabe MELCO SC, Tsukuba, Japan
	In 2013, the beam energy of the Japan Proton Accelerator Research Complex (J-PARC) linac is going to be increased from 181-MeV to 400-MeV by adding the annular-ring coupled structure (ACS) at the downstream of the 191-MeV drift tube linac. To install and operate all the ACS cavities in only five months of the energy upgrade shutdown in 2013, we decided to replace and upgrade all the related component of the beam line (cables, magnet power supplies and vacuum control systems) for the 400-MeV operation, in the period of the recovery from the Tohoku Earthquake which caused not negligible damage to the J-PARC accelerator facilities. The present beam line is operated by using some part of the 400-MeV componets. In this paper, the recovery of the beam transport, the present status and the future tasks of the beam energy upgrade will be presented.

THPB074	RF Photoinjector and Radiating Structure for High-power THz Radiation Source	coupling, electron, vacuum, impedance	1005
	S.M. Polozov, T.V. Bondarenko MEPhI, Moscow, Russia Y.A. Bashmakov LPI, Moscow, Russia
	Sources of high-power electromagnetic radiation in THz band are becoming promising as a new method of a low activation introscopy. Research and development of accelerating RF photoinjector and radiating system for THz radiation source are reported. The photoinjector is based on disk loaded waveguide (DLW). Two different designs of accelerating structures were modeled: widespread 1.6 cell of DLW structure and travelling wave resonator structure. The resonant models of these structures and the structures with power ports were designed. Electrodynamics characteristics and electric field distribution for all models were acquired. Results of picoseconds photoelectron beam dynamics in modeled structures are reported. Design of decelerating structures exciting Cherenkov radiation are based on corrugated metal channel and metal channel coated with dielectric. Analysis of radiation intensity and frequency band are presented.

THPB091	Machine Protection Issues and Solutions for Linear Accelerator Complexes	beam-losses, instrumentation, controls, linac	1032
	M. Jonker, H. Schmickler, R. Schmidt, D. Schulte CERN, Geneva, Switzerland M.C. Ross SLAC, Menlo Park, California, USA
	The workshop “Machine Protection focusing on Linear Accelerator Complexes” was held from 6-8 June 2012 at Cern. This workshop brought together experts working on machine protection systems for accelerator facilities with high brilliance or large stored beam energies, with the main focus on linear accelerators and their injectors. An overview of the machine protection systems for several accelerators was given. Beam loss mechanisms and their detection were discussed. Mitigation of failures and protection systems were presented. This paper summarises the workshop and reviews the current state of the art in machine protection systems.

THPB096	High-power Sources of RF Radiation Driven by Periodic Laser Pulses	laser, cavity, electron, klystron	1044
	S.V. Kuzikov, A.V. Savilov IAP/RAS, Nizhny Novgorod, Russia S.V. Kuzikov Omega-P, Inc., New Haven, USA
	Funding: Supported in part by DoE USA. A fast, periodic modulation of electron RF sources can be carried out in a form of Q-factor switching by means of fast RF switches, or in a form of I-switching by means of the bunched electron beam. If modulation frequency equals to time which is necessary for RF radiation to travel along the cavity and to come back, the RF oscillator can produce periodic, giant, short pulses which are desirable for many applications in order to avoid a breakdown. The produced RF pulses are phase and frequency locked by modulation shape. The mentioned effects of the phase and frequency locking remain also possible for RF sources operated in a single-mode regime. In last case the modulation frequency should be close to natural single-mode oscillation frequency. For example, one might control operation of a BWO by means of a small periodical modulation of the electron voltage in a drift section in-between a cathode and the corrugated interaction section. The necessary voltage modulation can be provided by means of a DC generator those voltage due to a photoconductivity is externally modulated with definite frequency by laser which irradiates GaAs isolator inserted in-between the electrodes.

Paper

Title

Other Keywords

Page

SUPB035

RF Photoinjector and Radiating Structure for High-power THz Radiation Source

coupling, electron, vacuum, impedance

86

S.M. Polozov, T.V. Bondarenko
MEPhI, Moscow, Russia
Y.A. Bashmakov
LPI, Moscow, Russia

Sources of high-power electromagnetic radiation in THz band are becoming promising as a new method of a low activation introscopy. Research and development of accelerating RF photoinjector and radiating system for THz radiation source are reported. The photoinjector is based on disk loaded waveguide (DLW). Two different designs of accelerating structures were modeled: widespread 1.6 cell of DLW structure and travelling wave resonator structure. The resonant models of these structures and the structures with power ports were designed. Electrodynamics characteristics and electric field distribution for all models were acquired. Results of picoseconds photoelectron beam dynamics in modeled structures are reported. Design of decelerating structures exciting Cherenkov radiation are based on corrugated metal channel and metal channel coated with dielectric. Analysis of radiation intensity and frequency band are presented.

MOPB051

Changing Attitude to Radiation Hazards and Consequent Opportunities for LINAC Applications

linac, electron, background, status

288

Y. Socol
Falcon Analytics, Netanya, Israel

High-energy LINACs unavoidably yield ionizing radiation. This fact makes them subject to strict regulations and considerably limits applications. During the last two decades the attitude to ionizing radiation hazards seems to become more balanced, as opposed to "radiophobia" of the Cold-War era. Scientifically, the linear no-threshold (LNT) model of radiation damage is more and more questioned. Moreover, the hypotheses of radiation hormesis - beneficial effect of low-dose radiation - is studied. While this scientific debate has not yet given fruit regarding radiation regulation and policy, we may expect this in near to middle term. Namely, the ALARA (as low as reasonably achievable) demand is anticipated to be substituted by some tolerance level, which in turn is anticipated to be very high according to the present standards. The presentation will review the present status of the radiation-hazard debate, and outline anticipated opportunities for LINAC applications, like compact designs and wider industrial outreach.

MOPB096

Beam Loss Mitigation in J-PARC Linac after the Tohoku Earthquake

linac, multipactoring, beam-losses, beam-transport

401

M. Ikegami, Z. Fang, K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
T. Maruta, A. Miura, J. Tamura, G.H. Wei
JAEA/J-PARC, Tokai-mura, Japan
H. Sako
JAEA, Ibaraki-ken, Japan

The beam operation of J-PARC linac was interrupted by the Tohoku earthquake in March 2011. After significant effort for its restoration, we have resumed the beam operation of J-PARC linac in December 2011. After resumption of beam operation, we have been suffering from beam losses which were not observed before the earthquake. Tackling with the beam loss issues, we have been reached the comparable beam power for user operation to the one before the earthquake. In this paper, we present the experience in the beam start-up tuning after the earthquake with emphasis on the beam loss mitigation efforts.

TUPB014

Comparative Design of Single Pass, Photo-cathode RF-LINAC FEL for the THz Frequency Range: Self Amplification vs. Enhanced Super-radiance

FEL, electron, linac, wiggler

507

Yu. Lurie, Y. Pinhasi
Ariel University Center of Samaria, Faculty of Engineering, Ariel, Israel

Self amplified spontaneous emission and enhanced super-radiance are discussed and compared as possible configurations in the construction of a single-pass, photo-cathode RF-LINAC FEL source for THz radiation, being developed in Ariel University Center of Samaria. Numerical simulations carried out using 3D, space-frequency approach demonstrate the charge squared dependence of the radiation power in both cases, the characteristic typical to super-radiant emission. The comparison reveals a high efficiency of an enhanced super-radiance FEL, which however can only be achieved with ultra-short (the radiation wavelength long or shorter) drive electron beam bunches at a proper energy chirping.

TUPB015

Warm Beamlines and Infrastructure in the European XFEL

linac, shielding, diagnostics, klystron

510

M. Hüning
DESY, Hamburg, Germany

The European XFEL is driven by a superconducting linear accelerator. In the main accelerator tunnel the accelerator modules will be suspended from the tunnel ceiling. The warm sections like bunch compressors will be installed on girders supported from the floor. The accelerator infrastructure like klystrons and electronic racks will be installed in the accelerator tunnel in close proximity to the electron beamline.

TUPB053

Main Coupler Design for Project X

vacuum, cavity, linac, cryomodule

594

S. Kazakov, S. Cheban, T.N. Khabiboulline, M. Kramp, Y. Orlov, V. Poloubotko, O. Pronitchev, V.P. Yakovlev
Fermilab, Batavia, USA
M.S. Champion
ORNL, Oak Ridge, Tennessee, USA

A multi-megawatt proton/H⁻ source, Project X, is under development at Fermi National Accelerator Laboratory. Main element of it is a 3 GeV superconducting proton linac which includes 5 families of superconducting cavities of three frequencies: 162.5, 325 and 650 MHz. Scope of this paper is the development of power couplers for 325 and 650 MHz at FNAL. Upgraded version of the accelerator will require two types of couplers, which reliably can operate at CW power level ~25 kW at 325 MHz and ~100 kW at 650 MHz respectively. In this paper we are describing the current design of these devices.

TUPB101

Beam Loss Occurred at DTL Cavity in J-PARC Linac

DTL, cavity, linac, drift-tube-linac

696

A. Miura, K. Hirano, T. Ito, T. Maruta
JAEA/J-PARC, Tokai-mura, Japan
M. Ikegami
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
T. Miyao, F. Naito, K. Nanmo
KEK, Ibaraki, Japan

The beam operation of J-PARC linac was suspended until December 2011 due to the damage by the Tohoku earthquake in March 2011. After resumed the operations, we measured the residual radiation along with the beam line during a short interval. Because the higher residual radiation was detected at the surface of drift tube linac (DTL) cavity by radiation survey, we installed the scintillation beam loss monitors (BLM) at the points where the higher radiation was detected to understand the cause of the radiation. Even the DTL section is low energy part of the linac, fine structure of the beam loss was observed by the scintillation BLM. And we measured the beam loss occurred at the DTL with the parameters of beam orbit and cavity settings. Also, the BLM is employed for the linac tuning. In this paper, the result of the radiation measurement and beam loss signals obtained by the scintillation BLMs are presented.

TH3A04

Plasmas, Dielectrics and the Ultrafast: First Science and Operational Experience at FACET

plasma, electron, linac, acceleration

802

C.I. Clarke, E. Adli, S. Corde, F.-J. Decker, R.J. England, R.A. Erickson, A.S. Fisher, S.J. Gessner, C. Hast, M.J. Hogan, S.Z. Li, N. Lipkowitz, M.D. Litos, Y. Nosochkov, J.T. Seeman, J. Sheppard, I. Tudosa, G.R. White, U. Wienands, M. Woodley, Z. Wu, G. Yocky
SLAC, Menlo Park, California, USA
C.E. Clayton, C. Joshi, W. Lu, K.A. Marsh, N. Vafaei
UCLA, Los Angeles, California, USA

Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515.
FACET (Facility for Advanced Accelerator and Experimental Tests) is an accelerator R&D test facility that has been recently constructed at SLAC National Accelerator Laboratory. The facility provides 20 GeV, 3 nC electron beams, short (20 um) bunches and small (20 um wide) spot sizes, producing uniquely high power beams. FACET supports studies from many fields but in particular those of Plasma Wakefield Acceleration and Dielectric Wakefield Acceleration. FACET is also a source of THz radiation for material studies. We present the FACET design, initial operating experience and first science from the facility.

Slides TH3A04 [3.091 MB]

THPB021

Recovery Efforts from the Tohoku Earthquake and Energy Upgrade Preparation of the Beam Transport from the J-PARC Linac to the 3-GeV Synchrotron

linac, beam-transport, synchrotron, vacuum

891

J. Tamura, H. Ao, H. Asano, T. Morishita, N. Ouchi
JAEA/J-PARC, Tokai-mura, Japan
Y. Sawabe
MELCO SC, Tsukuba, Japan

In 2013, the beam energy of the Japan Proton Accelerator Research Complex (J-PARC) linac is going to be increased from 181-MeV to 400-MeV by adding the annular-ring coupled structure (ACS) at the downstream of the 191-MeV drift tube linac. To install and operate all the ACS cavities in only five months of the energy upgrade shutdown in 2013, we decided to replace and upgrade all the related component of the beam line (cables, magnet power supplies and vacuum control systems) for the 400-MeV operation, in the period of the recovery from the Tohoku Earthquake which caused not negligible damage to the J-PARC accelerator facilities. The present beam line is operated by using some part of the 400-MeV componets. In this paper, the recovery of the beam transport, the present status and the future tasks of the beam energy upgrade will be presented.

THPB074

RF Photoinjector and Radiating Structure for High-power THz Radiation Source

coupling, electron, vacuum, impedance

1005

S.M. Polozov, T.V. Bondarenko
MEPhI, Moscow, Russia
Y.A. Bashmakov
LPI, Moscow, Russia

Sources of high-power electromagnetic radiation in THz band are becoming promising as a new method of a low activation introscopy. Research and development of accelerating RF photoinjector and radiating system for THz radiation source are reported. The photoinjector is based on disk loaded waveguide (DLW). Two different designs of accelerating structures were modeled: widespread 1.6 cell of DLW structure and travelling wave resonator structure. The resonant models of these structures and the structures with power ports were designed. Electrodynamics characteristics and electric field distribution for all models were acquired. Results of picoseconds photoelectron beam dynamics in modeled structures are reported. Design of decelerating structures exciting Cherenkov radiation are based on corrugated metal channel and metal channel coated with dielectric. Analysis of radiation intensity and frequency band are presented.

THPB091

Machine Protection Issues and Solutions for Linear Accelerator Complexes

beam-losses, instrumentation, controls, linac

1032

M. Jonker, H. Schmickler, R. Schmidt, D. Schulte
CERN, Geneva, Switzerland
M.C. Ross
SLAC, Menlo Park, California, USA

The workshop “Machine Protection focusing on Linear Accelerator Complexes” was held from 6-8 June 2012 at Cern. This workshop brought together experts working on machine protection systems for accelerator facilities with high brilliance or large stored beam energies, with the main focus on linear accelerators and their injectors. An overview of the machine protection systems for several accelerators was given. Beam loss mechanisms and their detection were discussed. Mitigation of failures and protection systems were presented. This paper summarises the workshop and reviews the current state of the art in machine protection systems.

THPB096

High-power Sources of RF Radiation Driven by Periodic Laser Pulses

laser, cavity, electron, klystron

1044

S.V. Kuzikov, A.V. Savilov
IAP/RAS, Nizhny Novgorod, Russia
S.V. Kuzikov
Omega-P, Inc., New Haven, USA

Funding: Supported in part by DoE USA.
A fast, periodic modulation of electron RF sources can be carried out in a form of Q-factor switching by means of fast RF switches, or in a form of I-switching by means of the bunched electron beam. If modulation frequency equals to time which is necessary for RF radiation to travel along the cavity and to come back, the RF oscillator can produce periodic, giant, short pulses which are desirable for many applications in order to avoid a breakdown. The produced RF pulses are phase and frequency locked by modulation shape. The mentioned effects of the phase and frequency locking remain also possible for RF sources operated in a single-mode regime. In last case the modulation frequency should be close to natural single-mode oscillation frequency. For example, one might control operation of a BWO by means of a small periodical modulation of the electron voltage in a drift section in-between a cathode and the corrugated interaction section. The necessary voltage modulation can be provided by means of a DC generator those voltage due to a photoconductivity is externally modulated with definite frequency by laser which irradiates GaAs isolator inserted in-between the electrodes.