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Title: Transverse-to-longitudinal Emittance-exchange with an Energy Chirped Beam

Abstract

Emittance exchange has been proposed to increase the performance of free electron lasers by tailoring the phase space of an electron beam. The principle of emittance exchange - where the transverse phase space of the electron beam is exchanged with the longitudinal phase space - has been demonstrated recently at the A0 photoinjector. The experiment used a low charge bunch (250 pC) with no energy chirp. Theory predicts an improvement in the emittance exchange scheme when the incoming beam has an energy chirp imparted on it. The energy chirp helps to overcome the thick lens effect of the deflecting mode cavity and other second order effects that might lead to an incomplete emittance exchange at higher charges. In this work, we report experimental and simulation results from operating the emittance exchange beam line using an energy chirped beam with higher charge (500 pC) at different RF-chirp settings.

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1048442
Report Number(s):
FERMILAB-CONF-12-161-APC
TRN: US1204211
DOE Contract Number:
AC02-07CH11359
Resource Type:
Conference
Resource Relation:
Journal Name: Conf.Proc.C1205201:49-51,2012; Conference: Presented at the 3rd International Particle Accelerator Conference (IPAC-2012), New Orleans, Louisiana, 20-25 May 2012
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCELERATORS; ELECTRON BEAMS; FREE ELECTRON LASERS; PERFORMANCE; PHASE SPACE; SIMULATION; Accelerators

Citation Formats

Thangaraj, J., Ruan, J., Johnson, A.S., Thurman-Keup, R., Lumpkin, A.H., Santucci, J., Sun, Y.-E, Maxwell, T., Edwards, H., and /Fermilab. Transverse-to-longitudinal Emittance-exchange with an Energy Chirped Beam. United States: N. p., 2012. Web.
Thangaraj, J., Ruan, J., Johnson, A.S., Thurman-Keup, R., Lumpkin, A.H., Santucci, J., Sun, Y.-E, Maxwell, T., Edwards, H., & /Fermilab. Transverse-to-longitudinal Emittance-exchange with an Energy Chirped Beam. United States.
Thangaraj, J., Ruan, J., Johnson, A.S., Thurman-Keup, R., Lumpkin, A.H., Santucci, J., Sun, Y.-E, Maxwell, T., Edwards, H., and /Fermilab. 2012. "Transverse-to-longitudinal Emittance-exchange with an Energy Chirped Beam". United States. doi:. https://www.osti.gov/servlets/purl/1048442.
@article{osti_1048442,
title = {Transverse-to-longitudinal Emittance-exchange with an Energy Chirped Beam},
author = {Thangaraj, J. and Ruan, J. and Johnson, A.S. and Thurman-Keup, R. and Lumpkin, A.H. and Santucci, J. and Sun, Y.-E and Maxwell, T. and Edwards, H. and /Fermilab},
abstractNote = {Emittance exchange has been proposed to increase the performance of free electron lasers by tailoring the phase space of an electron beam. The principle of emittance exchange - where the transverse phase space of the electron beam is exchanged with the longitudinal phase space - has been demonstrated recently at the A0 photoinjector. The experiment used a low charge bunch (250 pC) with no energy chirp. Theory predicts an improvement in the emittance exchange scheme when the incoming beam has an energy chirp imparted on it. The energy chirp helps to overcome the thick lens effect of the deflecting mode cavity and other second order effects that might lead to an incomplete emittance exchange at higher charges. In this work, we report experimental and simulation results from operating the emittance exchange beam line using an energy chirped beam with higher charge (500 pC) at different RF-chirp settings.},
doi = {},
journal = {Conf.Proc.C1205201:49-51,2012},
number = ,
volume = ,
place = {United States},
year = 2012,
month = 5
}

Conference:
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  • Transverse-to-longitudinal emittance exchange has promising applications in various advanced acceleration and light source concepts. A proof-of-principle experiment to demonstrate this phase space manipulation method is currently being planned at the Argonne Wakefield Accelerator. The experiment focuses on exchanging a low longitudinal emittance with a high transverse horizontal emittance and also incorporates room for possible parametric studies e.g. using an incoming flat beam with tunable horizontal emittance. In this paper, we present realistic start-to-end beam dynamics simulation of the scheme, explore the limitations of this phase space exchange.
  • Transverse-to-longitudinal emittance exchange has promising applications in various advanced acceleration and light source concepts. A proof-of-principle experiment to demonstrate this phase space manipulation method is currently being planned at the Argonne Wakefield Accelerator. The experiment focuses on exchanging a low longitudinal emittance with a high transverse horizontal emittance and also incorporates room for possible parametric studies e.g. using an incoming flat beam with tunable horizontal emittance. In this paper, we present realistic start-to-end beam dynamics simulation of the scheme, explore the limitations of this phase space exchange.
  • A transverse-to-longitudinal emittance exchange experiment is in preparation at the Argonne Wakefield Accelerator (AWA). The experiment aims at exchanging a low ({var_epsilon}{sub z} < 5 {micro}m) longitudinal emittance with a large ({var_epsilon}{sub x} > 15 {micro}m) transverse horizontal emittance for a bunch charge of {approx}100 pC. Achieving such initial emittance partitioning, though demonstrated via numerical simulations, is a challenging task and needs to be experimentally verified. In this paper, we report preliminary emittance measurements of the beam in the transverse and longitudinal planes performed at {approx}12 MeV. The measurements are compared with numerical simulations.
  • Transverse to longitudinal phase space manipulation hold great promises, e.g., as a potential technique for repartitioning the emittances of a beam. A proof-of-principle experiment to demonstrate the exchange of a low longitudinal emittance with a larger transverse emittance is in preparation at the Argonne Wakefield Accelerator using a {approx}12 MeV electron beam. In this paper we explore the limiting effects of this phase space manipulation method including high order and collective effects. A realistic start-to-end simulation of the planned proof-of-principle experiment including sensitivity studies is also presented.
  • The FNAL A0 Photoinjector is being reconfigured to test the principal of transverse to longitudinal emittance exchange as proposed by Cornacchia and Emma, Kim and Sessler, and others. The ability to perform such an exchange could have major advantages to FELs by reducing the transverse emittance. Several schemes to carry out the exchange are possible and will be reported separately. At the Fermilab A0 Photoinjector we are constructing a beamline to demonstrate this transverse to longitudinal emittance exchange. This beamline will consist of a dogleg, a TM{sub 110} 5 cell copper cavity, and another dogleg. The beamline is designed tomore » reuse the bunch compressor dipoles of the photoinjector, along with some existing diagnostics. Beamline layout and simulations are presented. Emittance dilution effects are also discussed.« less