IPAC2011 - Classification: 03 Linear Colliders, Lepton Accelerators and New Acceleration Techniques / A13 New Acceleration Techniques

Paper

Title

Page

Advanced Acceleration Schemes

1945

P.A. Naik, P.D. Gupta, B.S. Rao
RRCAT, Indore (M.P.), India

Review the progress and prospects of advanced acceleration concepts, including plasma acceleration, laser acceleration, and dielectric accelerators. Report ongoing and near-future experiments, and longer-term prospects for applications (e.g. compact X-ray sources, linear colliders, hadrontherapy).

Slides WEXB01 [8.636 MB]

WEPZ002

Chromatic, Geometric and Space Charge Effects on Laser Accelerated Protons Focused by a Solenoid

2766

H.Y. Al-Omari, U. Ratzinger
IAP, Frankfurt am Main, Germany
I. Hofmann
GSI, Darmstadt, Germany

We studied numerically emittance and transmission effects by chromatic and geometric aberrations, with and without space charge, for a proton beam behind a solenoid in the laser proton experiment LIGHT at GSI. The TraceWin code was employed using a field map for the solenoid and an initial distribution with exponential energy dependence close to the experiment. The results show a strong effect of chromatic, and a relatively weak one of geometric aberrations as well as dependence of proton transmission on distance from the solenoid. The chromatic effect has an energy filtering property due to the finite radius beam pipe. Furthermore, a relatively modest dependence of transmission on space charge is found for p production intensity below 10¹1.

WEPZ004

Solid Pulse Transforming Line for DWA

2769

L. Zhang
CAEP/IFP, Mainyang, Sichuan, People's Republic of China

This paper introduces the research work about solid pulse transforming line for dielectric wall accelerator(DWA). We will discuss the impedence of the solid pulse transforming line due to different material. Some research of PCSS(photoconductive semiconductor switch),which was used for DWA, will also be described.

WEPZ005

Field Calculations to obtain Attosecond/Femtosecond Electron Bunches

2772

V.A. Papadichev
LPI, Moscow, Russia

Obtaining short electron bunches of attosecond and femtosecond duration in a combined quasi-static and laser electric field [* - ****] requires careful field formation in the cathode region. First, the maximum of laser electric field normal to the cathode plate, depending on the incidence angle, was found employing Fresnel formulae using complex dielectric permittivity of metals. Second, laser field enhancement on cathode spikes was calculated for the case of an ellipsoid in a qusi-static approximation (laser wavelength larger than spike dimensions). Field enhancement is approximately proportional to the square of the ratio of major to minor axes of ellipsoid. Thus, enhancement factors as large as 100 - 1000 are obtainable, allowing to reduce laser power by 10 thousand to 1 million times.
* V.A.Papadichev, Patent RU 2 269 877 C1, 10.02.06, Bull. 4.
** V.A.Papadichev, Proc. EPAC08, p.2812.
*** V.A.Papadichev, Proc. EPAC08, p.2815.
**** V.A.Papadichev, Proc. IPAC'10, p. 4372

WEPZ006

Forming Attosecond Electron Pulses in Space-charge Dominated Regime

2775

V.A. Papadichev
LPI, Moscow, Russia

Production of high-current attosecond electron pulses requires studying of the final bunching stage, which inevitably is space-charge dominated [*, **, ***]. Two models are studied, both allow solving a one-dimensional equation of motion. The first is for a spherical bunch, which corresponds to a short emitted pulse from a one-spike cathode of diameter approximately equal to its length. The second model is suited for pulses emitted from a multi-spike or multi-blade cathode. The bunch in the latter case is a thin plate and its evolution can be studied by also solving one-dimensional equation of motion. It was shown that bunches of 10-attosecond (as) duration with peak current of dozens of amperes can be obtained when using a carbon dioxide laser and less than 0.1-as duration with currents up to 1 MA when employing a neodymium laser. Beam focusing in transverse directions is also studied using a model. Possible applications of such electron bunches are reviewed, including obtaining attosecond pulses of tunable coherent radiation in UV and X-ray regions.
* V.A.Papadichev, Proceedings of EPAC08, p.2815.
** V.A.Papadichev, Proceedings of IPAC'10, Kyoto, Japan, p. 4372.
*** V.A.Papadichev, Proc. RUPAC-2010, TUPSAO10, p. 56.

WEPZ007

Multi-mode, Two-beam Accelerator with Feedback

2778

S.V. Kuzikov, M.E. Plotkin
IAP/RAS, Nizhny Novgorod, Russia

A high-gradient accelerator consisted of the test and the drive beam structures is reported. The accelerating structure can be based on dielectric or corrugated cavities separated each other by irises. Each cavity is operated by several axisymmetric, TM-like eigen-modes with longitudinal indices to be related to frequencies. These modes are excited at Fourier harmonics of the drive current which consists of bunches spaced with the same period as test bunches. The superposition of the excited modes introduces a short RF pulse propagated in-phase with a moving test bunch and after reflection by iris (a feedback) this pulse can accelerate next bunch. Such longitudinally-sweeping RF field promises a reduction of the exposure time and due to compact space shape can help to obtain high shunt impedance.

WEPZ008

Experimental Plans to Explore Dielectric Wakefield Acceleration in the THz Regime

2781

F. Lemery, D. Mihalcea, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
C. Behrens, E. Elsen, K. Flöttmann, C. Gerth, G. Kube, B. Schmidt
DESY, Hamburg, Germany
J. Osterhoff
LBNL, Berkeley, California, USA
P. Stoltz
Tech-X, Boulder, Colorado, USA

Funding: This work was supported by the Defense Threat Reduction Agency, Basic Research Award \# HDTRA1-10^-1-0051, to Northern Illinois University
Dielectric wakefield accelerators have shown great promise toward high-gradient acceleration. We investigate tow experiments in preparation to explore the performance of cylindrically-symmetric and slab-shaped dielectric-loaded waveguides. The planned experiments at Fermilab and DESY will use unique pulse shaping capabilities offered at these facilities. The superconducting test accelerator at FNAL will ultimately provide flat beams with variable current profiles needed for enhancing the transformer ratio. The FLASH facility at DESY recently demonstrated the generation of a ramped round beam current profile that will enable us to explore the performance of cylindrically-symmetric structures. Finally both of these facilities incorporate superconducting linear accelerator that could generate bunch trains with closely spaced bunches thereby opening the exploration of dynamical effects in dielectric wakefield accelerators. We present the planned layout and simulated experimental performances.

WEPZ009

Parametric-Resonance Ionization Cooling in Twin-Helix

2784

V.S. Morozov, Y.S. Derbenev
JLAB, Newport News, Virginia, USA
A. Afanasev, R.P. Johnson
Muons, Inc, Batavia, USA
B. Erdelyi, J.A. Maloney
Northern Illinois University, DeKalb, Illinois, USA

Funding: Supported in part by DOE SBIR grant DE-SC0005589. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a high-luminosity muon collider. For the implementation of PIC, we developed an epicyclic twin-helix channel with correlated optics. Wedge-shaped absorbers immediately followed by short rf cavities are placed into the twin-helix channel. Parametric resonances are induced in both planes using helical quadrupole harmonics. We demonstrate resonant dynamics and cooling with stochastic effects off using GEANT4/ G4beamline. We illustrate compensation of spherical aberrations and benchmark COSY Infinity, a powerful tool for aberration analysis and compensation.

WEPZ010

Modeling and Experimental Update on Direct Laser Acceleration

2787

I. Jovanovic, M.W. Lin
Penn State University, University Park, Pennsylvania, USA

Funding: This work is supported by the Defense Threat Reduction Agency under contract HDTRA1-11-1-0009.
Moderate-energy, high-repetition-rate electron beams are needed in a variety of applications such as those in security and medicine, while requiring that the acceleration be realized in a compact and relatively inexpensive package. Laser wakefield acceleration is an attractive technology which meets most of those requirements, but it requires the use of relatively high peak power lasers which do not scale readily to high repetition rates. We are developing the theoretical and experimental basis for advancing the science and technology of direct laser acceleration (DLA) of charged particles using the axial component of the electric field of a radially polarized intense laser pulse. DLA is an acceleration method which exhibits no threshold and is thus compatible with the use of lower peak power, but much higher repetition rate lasers. We are currently numerically investigating the conditions for quasi-phase-matched DLA of electrons in plasma waveguides and experimentally implementing the quasi-phase-matched waveguide structure in laser-produced plasmas.

Paper	Title	Page
WEXB01	Advanced Acceleration Schemes	1945
	P.A. Naik, P.D. Gupta, B.S. Rao RRCAT, Indore (M.P.), India
	Review the progress and prospects of advanced acceleration concepts, including plasma acceleration, laser acceleration, and dielectric accelerators. Report ongoing and near-future experiments, and longer-term prospects for applications (e.g. compact X-ray sources, linear colliders, hadrontherapy).
	Slides WEXB01 [8.636 MB]

WEPZ002	Chromatic, Geometric and Space Charge Effects on Laser Accelerated Protons Focused by a Solenoid	2766
	H.Y. Al-Omari, U. Ratzinger IAP, Frankfurt am Main, Germany I. Hofmann GSI, Darmstadt, Germany
	We studied numerically emittance and transmission effects by chromatic and geometric aberrations, with and without space charge, for a proton beam behind a solenoid in the laser proton experiment LIGHT at GSI. The TraceWin code was employed using a field map for the solenoid and an initial distribution with exponential energy dependence close to the experiment. The results show a strong effect of chromatic, and a relatively weak one of geometric aberrations as well as dependence of proton transmission on distance from the solenoid. The chromatic effect has an energy filtering property due to the finite radius beam pipe. Furthermore, a relatively modest dependence of transmission on space charge is found for p production intensity below 10¹1.

WEPZ004	Solid Pulse Transforming Line for DWA	2769
	L. Zhang CAEP/IFP, Mainyang, Sichuan, People's Republic of China
	This paper introduces the research work about solid pulse transforming line for dielectric wall accelerator(DWA). We will discuss the impedence of the solid pulse transforming line due to different material. Some research of PCSS(photoconductive semiconductor switch),which was used for DWA, will also be described.

WEPZ005	Field Calculations to obtain Attosecond/Femtosecond Electron Bunches	2772
	V.A. Papadichev LPI, Moscow, Russia
	Obtaining short electron bunches of attosecond and femtosecond duration in a combined quasi-static and laser electric field [* - ***] requires careful field formation in the cathode region. First, the maximum of laser electric field normal to the cathode plate, depending on the incidence angle, was found employing Fresnel formulae using complex dielectric permittivity of metals. Second, laser field enhancement on cathode spikes was calculated for the case of an ellipsoid in a qusi-static approximation (laser wavelength larger than spike dimensions). Field enhancement is approximately proportional to the square of the ratio of major to minor axes of ellipsoid. Thus, enhancement factors as large as 100 - 1000 are obtainable, allowing to reduce laser power by 10 thousand to 1 million times. V.A.Papadichev, Patent RU 2 269 877 C1, 10.02.06, Bull. 4. V.A.Papadichev, Proc. EPAC08, p.2812. * V.A.Papadichev, Proc. EPAC08, p.2815. **** V.A.Papadichev, Proc. IPAC'10, p. 4372

WEPZ006	Forming Attosecond Electron Pulses in Space-charge Dominated Regime	2775
	V.A. Papadichev LPI, Moscow, Russia
	Production of high-current attosecond electron pulses requires studying of the final bunching stage, which inevitably is space-charge dominated [, , *]. Two models are studied, both allow solving a one-dimensional equation of motion. The first is for a spherical bunch, which corresponds to a short emitted pulse from a one-spike cathode of diameter approximately equal to its length. The second model is suited for pulses emitted from a multi-spike or multi-blade cathode. The bunch in the latter case is a thin plate and its evolution can be studied by also solving one-dimensional equation of motion. It was shown that bunches of 10-attosecond (as) duration with peak current of dozens of amperes can be obtained when using a carbon dioxide laser and less than 0.1-as duration with currents up to 1 MA when employing a neodymium laser. Beam focusing in transverse directions is also studied using a model. Possible applications of such electron bunches are reviewed, including obtaining attosecond pulses of tunable coherent radiation in UV and X-ray regions. V.A.Papadichev, Proceedings of EPAC08, p.2815. V.A.Papadichev, Proceedings of IPAC'10, Kyoto, Japan, p. 4372. * V.A.Papadichev, Proc. RUPAC-2010, TUPSAO10, p. 56.

WEPZ007	Multi-mode, Two-beam Accelerator with Feedback	2778
	S.V. Kuzikov, M.E. Plotkin IAP/RAS, Nizhny Novgorod, Russia
	A high-gradient accelerator consisted of the test and the drive beam structures is reported. The accelerating structure can be based on dielectric or corrugated cavities separated each other by irises. Each cavity is operated by several axisymmetric, TM-like eigen-modes with longitudinal indices to be related to frequencies. These modes are excited at Fourier harmonics of the drive current which consists of bunches spaced with the same period as test bunches. The superposition of the excited modes introduces a short RF pulse propagated in-phase with a moving test bunch and after reflection by iris (a feedback) this pulse can accelerate next bunch. Such longitudinally-sweeping RF field promises a reduction of the exposure time and due to compact space shape can help to obtain high shunt impedance.

WEPZ008	Experimental Plans to Explore Dielectric Wakefield Acceleration in the THz Regime	2781
	F. Lemery, D. Mihalcea, P. Piot Northern Illinois University, DeKalb, Illinois, USA C. Behrens, E. Elsen, K. Flöttmann, C. Gerth, G. Kube, B. Schmidt DESY, Hamburg, Germany J. Osterhoff LBNL, Berkeley, California, USA P. Stoltz Tech-X, Boulder, Colorado, USA
	Funding: This work was supported by the Defense Threat Reduction Agency, Basic Research Award \# HDTRA1-10^-1-0051, to Northern Illinois University Dielectric wakefield accelerators have shown great promise toward high-gradient acceleration. We investigate tow experiments in preparation to explore the performance of cylindrically-symmetric and slab-shaped dielectric-loaded waveguides. The planned experiments at Fermilab and DESY will use unique pulse shaping capabilities offered at these facilities. The superconducting test accelerator at FNAL will ultimately provide flat beams with variable current profiles needed for enhancing the transformer ratio. The FLASH facility at DESY recently demonstrated the generation of a ramped round beam current profile that will enable us to explore the performance of cylindrically-symmetric structures. Finally both of these facilities incorporate superconducting linear accelerator that could generate bunch trains with closely spaced bunches thereby opening the exploration of dynamical effects in dielectric wakefield accelerators. We present the planned layout and simulated experimental performances.

WEPZ009	Parametric-Resonance Ionization Cooling in Twin-Helix	2784
	V.S. Morozov, Y.S. Derbenev JLAB, Newport News, Virginia, USA A. Afanasev, R.P. Johnson Muons, Inc, Batavia, USA B. Erdelyi, J.A. Maloney Northern Illinois University, DeKalb, Illinois, USA
	Funding: Supported in part by DOE SBIR grant DE-SC0005589. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a high-luminosity muon collider. For the implementation of PIC, we developed an epicyclic twin-helix channel with correlated optics. Wedge-shaped absorbers immediately followed by short rf cavities are placed into the twin-helix channel. Parametric resonances are induced in both planes using helical quadrupole harmonics. We demonstrate resonant dynamics and cooling with stochastic effects off using GEANT4/ G4beamline. We illustrate compensation of spherical aberrations and benchmark COSY Infinity, a powerful tool for aberration analysis and compensation.

WEPZ010	Modeling and Experimental Update on Direct Laser Acceleration	2787
	I. Jovanovic, M.W. Lin Penn State University, University Park, Pennsylvania, USA
	Funding: This work is supported by the Defense Threat Reduction Agency under contract HDTRA1-11-1-0009. Moderate-energy, high-repetition-rate electron beams are needed in a variety of applications such as those in security and medicine, while requiring that the acceleration be realized in a compact and relatively inexpensive package. Laser wakefield acceleration is an attractive technology which meets most of those requirements, but it requires the use of relatively high peak power lasers which do not scale readily to high repetition rates. We are developing the theoretical and experimental basis for advancing the science and technology of direct laser acceleration (DLA) of charged particles using the axial component of the electric field of a radially polarized intense laser pulse. DLA is an acceleration method which exhibits no threshold and is thus compatible with the use of lower peak power, but much higher repetition rate lasers. We are currently numerically investigating the conditions for quasi-phase-matched DLA of electrons in plasma waveguides and experimentally implementing the quasi-phase-matched waveguide structure in laser-produced plasmas.