skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Observation of Enhanced Transformer Ratio in Collinear Wakefield Acceleration

Abstract

One approach to future high energy particle accelerators is based on the wakefield principle: a leading high-charge drive bunch is used to excite fields in an accelerating structure or plasma that in turn accelerates a trailing low-charge witness bunch. The transformer ratio R is defined as the ratio of the maximum energy gain of the witness bunch to the maximum energy loss of the drive bunch. In general, R<2 for this configuration. A number of techniques have been proposed to overcome the transformer ratio limitation. We report here the first experimental study of the ramped bunch train (RBT) technique in a dielectric based accelerating structure. A single drive bunch was replaced by two bunches with charge ratio of 1 ratio 2.5 and a separation of 10.5 wavelengths of the fundamental mode. An average measured transformer ratio enhancement by a factor of 1.31 over the single drive bunch case was obtained.

Authors:
; ;  [1]; ; ; ;  [2]
  1. Euclid Techlabs LLC, Solon, Ohio 44139 (United States)
  2. High Energy Physics Division, Argonne National Laboratory, Argonne, Illinois-60439 (United States)
Publication Date:
OSTI Identifier:
20951211
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 14; Other Information: DOI: 10.1103/PhysRevLett.98.144801; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCELERATION; DIELECTRIC MATERIALS; ENERGY LOSSES; MINUS-PLUS RATIO; PLASMA; TRANSFORMERS; WAKEFIELD ACCELERATORS; WAVELENGTHS

Citation Formats

Jing, C., Kanareykin, A., Schoessow, P., Power, J. G., Conde, M., Yusof, Z., and Gai, W. Observation of Enhanced Transformer Ratio in Collinear Wakefield Acceleration. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.144801.
Jing, C., Kanareykin, A., Schoessow, P., Power, J. G., Conde, M., Yusof, Z., & Gai, W. Observation of Enhanced Transformer Ratio in Collinear Wakefield Acceleration. United States. doi:10.1103/PHYSREVLETT.98.144801.
Jing, C., Kanareykin, A., Schoessow, P., Power, J. G., Conde, M., Yusof, Z., and Gai, W. Fri . "Observation of Enhanced Transformer Ratio in Collinear Wakefield Acceleration". United States. doi:10.1103/PHYSREVLETT.98.144801.
@article{osti_20951211,
title = {Observation of Enhanced Transformer Ratio in Collinear Wakefield Acceleration},
author = {Jing, C. and Kanareykin, A. and Schoessow, P. and Power, J. G. and Conde, M. and Yusof, Z. and Gai, W.},
abstractNote = {One approach to future high energy particle accelerators is based on the wakefield principle: a leading high-charge drive bunch is used to excite fields in an accelerating structure or plasma that in turn accelerates a trailing low-charge witness bunch. The transformer ratio R is defined as the ratio of the maximum energy gain of the witness bunch to the maximum energy loss of the drive bunch. In general, R<2 for this configuration. A number of techniques have been proposed to overcome the transformer ratio limitation. We report here the first experimental study of the ramped bunch train (RBT) technique in a dielectric based accelerating structure. A single drive bunch was replaced by two bunches with charge ratio of 1 ratio 2.5 and a separation of 10.5 wavelengths of the fundamental mode. An average measured transformer ratio enhancement by a factor of 1.31 over the single drive bunch case was obtained.},
doi = {10.1103/PHYSREVLETT.98.144801},
journal = {Physical Review Letters},
number = 14,
volume = 98,
place = {United States},
year = {Fri Apr 06 00:00:00 EDT 2007},
month = {Fri Apr 06 00:00:00 EDT 2007}
}
  • No abstract prepared.
  • The transformer ratio R is a parameter that characterizes the efficiency of the energy transferred from the drive beam to the trailing witness beam passing through a wakefield accelerating structure (all metal or dielectric based) or a plasma chamber. Using a ramped bunch train (RBT) rather than a single drive bunch, the enhanced transformer ratio (ETR) technique is able to increase the transformer ratio R above the ordinary limit of 2 for a single bunch in a collinear wakefield accelerator. The RBT is a train of electron bunches separated by half integer multiples wavelength of the wakefield. The charge ofmore » the leading bunch is lowest and subsequent bunch charges are increased in such a way as to maximize R. In this article, an experimental study of this scheme is presented in which an RBT of 2 bunches with charge ratio of 1:2.5 and bunch length {sigma}z = 2 mm were used to enhance the transformer ratio. Measurement results and data analysis show good agreement with theoretical predictions. The ETR technique demonstrated here can be used in any collinear wakefield accelerator configuration, either structure- or plasma-based.« less
  • The transformer ratio R is a parameter that characterizes the efficiency of the energy transferred from the drive beam to the trailing witness beam passing through a wakefield accelerating structure (all metal or dielectric based) or a plasma chamber. Using a ramped bunch train (RBT) rather than a single drive bunch, the enhanced transformer ratio (ETR) technique is able to increase the transformer ratio R above the ordinary limit of 2 for a single bunch in a collinear wakefield accelerator. The RBT is a train of electron bunches separated by half integer multiples wavelength of the wakefield. The charge ofmore » the leading bunch is lowest and subsequent bunch charges are increased in such a way as to maximize R. In this article, an experimental study of this scheme is presented in which an RBT of 2 bunches with charge ratio of 1:2.5 and bunch length {sigma}{sub z} = 2 mm were used to enhance the transformer ratio. Measurement results and data analysis show good agreement with theoretical predictions. The ETR technique demonstrated here can be used in any collinear wakefield accelerator configuration, either structure- or plasma-based.« less
  • Here, the interrelation between the accelerating gradient and the transformer ratio in the collinear wake field accelerator has been analyzed. It has been shown that the high transformer ratio and the high efficiency of the energy transfer from the drive bunch to the witness bunch can only be achieved at the expense of the accelerating gradient. Rigorous proof is given that in best cases of meticulously shaped charge density distributions in the drive bunch, the maximum accelerating gradient falls proportionally to the gain in the transformer ratio. Conclusions are verified using several representative examples.