FEL2012 - List of Authors (Lumpkin, A.H.)

Paper	Title	Page
WEPD18	Potential for Laser-induced Microbunching Studies with the 3-MHz-rate Electron Beams at ASTA	409
	A.H. Lumpkin, J. Ruan Fermilab, Batavia, USA J.M. Byrd, R.B. Wilcox LBNL, Berkeley, California, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. Investigations of the laser-induced microbunching as it is related to time-sliced electron-beam diagnostics and high-gain-harmonic generation (HGHG) free-electron lasers using bright electron beams are proposed for the Advanced Superconducting Test Accelerator (ASTA) facility at Fermilab. Initial tests at 40-50 MeV with an amplified 800-nm seed laser beam co-propagating with the electron beam through a short undulator (or modulator) tuned for the third-harmonic resonance condition followed by transport through a subsequent chicane will result in energy modulation and z-density modulation (microbunching), respectively. The latter microbunching will result in generation of coherent optical or UV transition radiation (COTR, CUVTR) at a metal converter screen which can reveal slice beam size, centroid, and energy spread. Additionally, direct assessment of the microbunching factors related to HGHG by measurement of the COTR intensity and harmonic content after the chicane as a function of seed laser power and beam parameters will be done. These experiments will be performed using the ASTA 1-MHz-rate micropulse train for up to 1ms which is unique to test facilities in the USA.

THPD25	Feasibility of Diagnostics Undulator Studies at ASTA	591
	A.H. Lumpkin, M. Wendt Fermilab, Batavia, USA J.M. Byrd LBNL, Berkeley, California, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The high-power electron beams for the Advanced Superconducting Test Accelerator (ASTA) facility involve up to 3000 micropulses with up to 3.2 nC per micropulse in a 1-ms macropulse. With beam energies projected from 45 to 800 MeV the need for non-intercepting diagnostics for beam size, position, energy, and bunch length is clear. Besides the rf BPMs, optical synchrotron radiation (OSR), and optical diffraction radiation (ODR) techniques already planned, we propose the use of undulator radiation from a dedicated device for diagnostics with a nominal period of 4-5 cm, a tunable field parameter K, and a length of several meters. We propose time resolving the e-beam properties within the macropulse by viewing the undulator radiation with standard gated ICCD's (size and position) and a streak camera coupled to an optical spectrometer (energy, bunch length, and phase). The feasibility of extending such techniques in the visible regime at a beam energy of 125 MeV into the UV and VUV regimes with beam energies of 250 and 500 MeV will be presented.

Paper

Title

Page

Potential for Laser-induced Microbunching Studies with the 3-MHz-rate Electron Beams at ASTA

409

A.H. Lumpkin, J. Ruan
Fermilab, Batavia, USA
J.M. Byrd, R.B. Wilcox
LBNL, Berkeley, California, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Investigations of the laser-induced microbunching as it is related to time-sliced electron-beam diagnostics and high-gain-harmonic generation (HGHG) free-electron lasers using bright electron beams are proposed for the Advanced Superconducting Test Accelerator (ASTA) facility at Fermilab. Initial tests at 40-50 MeV with an amplified 800-nm seed laser beam co-propagating with the electron beam through a short undulator (or modulator) tuned for the third-harmonic resonance condition followed by transport through a subsequent chicane will result in energy modulation and z-density modulation (microbunching), respectively. The latter microbunching will result in generation of coherent optical or UV transition radiation (COTR, CUVTR) at a metal converter screen which can reveal slice beam size, centroid, and energy spread. Additionally, direct assessment of the microbunching factors related to HGHG by measurement of the COTR intensity and harmonic content after the chicane as a function of seed laser power and beam parameters will be done. These experiments will be performed using the ASTA 1-MHz-rate micropulse train for up to 1ms which is unique to test facilities in the USA.

THPD25

Feasibility of Diagnostics Undulator Studies at ASTA

591

A.H. Lumpkin, M. Wendt
Fermilab, Batavia, USA
J.M. Byrd
LBNL, Berkeley, California, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The high-power electron beams for the Advanced Superconducting Test Accelerator (ASTA) facility involve up to 3000 micropulses with up to 3.2 nC per micropulse in a 1-ms macropulse. With beam energies projected from 45 to 800 MeV the need for non-intercepting diagnostics for beam size, position, energy, and bunch length is clear. Besides the rf BPMs, optical synchrotron radiation (OSR), and optical diffraction radiation (ODR) techniques already planned, we propose the use of undulator radiation from a dedicated device for diagnostics with a nominal period of 4-5 cm, a tunable field parameter K, and a length of several meters. We propose time resolving the e-beam properties within the macropulse by viewing the undulator radiation with standard gated ICCD's (size and position) and a streak camera coupled to an optical spectrometer (energy, bunch length, and phase). The feasibility of extending such techniques in the visible regime at a beam energy of 125 MeV into the UV and VUV regimes with beam energies of 250 and 500 MeV will be presented.