IPAC2015 - List of Authors (Nguyen, D.C.)

Paper	Title	Page
TUPMA026	Status of the MaRIE X-FEL Accelerator Design	1894
	J.W. Lewellen, K. Bishofberger, B.E. Carlsten, L.D. Duffy, F.L. Krawczyk, Q.R. Marksteiner, D.C. Nguyen, S.J. Russell, R.L. Sheffield, N.A. Yampolsky LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by the MaRIE program at Los Alamos National Laboratory, under contract DE-AC52-06NA25396 The Matter-Radiation Interactions in Extremes (MaRIE) facility is intended to probe and control the time-dependent properties of materials under extreme conditions. At its core, the “MaRIE 1.0” X-FEL is being designed to deliver pulse trains of ~10¹⁰ 42 keV photons, with a minimum bunch spacing of 2.4 ns, enabling time-dependent studies particularly of mesoscale phenomena. The X-FEL accelerator is also intended to deliver a series of 2 nC electron bunches to enable electron radiography concurrently with the X-ray pulse train, so as to provide multi-probe capability to MaRIE. In 2014, the reference design for the MaRIE X-FEL 12 GeV driver linac was changed from an S-band normal-conducting to an L-band superconducting linac to accommodate pulse trains up to 100 μs in duration. This paper does not present a complete solution for the MaRIE linac design; rather it describes our current reference design, achieved parameters, areas of concern and paths towards mitigation of identified issues.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA026
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TUPMA033	A Bunch Compression Method for Free Electron Lasers that Avoids Parasitic Compressions	1907
	S.V. Benson, D. Douglas, C. Tennant, F.G. Wilson JLab, Newport News, Virginia, USA D.C. Nguyen LANL, Los Alamos, New Mexico, USA
	Funding: This work was supported by U.S. DOE Contract No. DE-AC05-84-ER40150, the Air Force Office of Scientific Research, DOE Basic Energy Sciences. Virtually all existing high energy (>few MeV) linac-driven FELs compress the electron bunch length though the use of off-crest acceleration on the rising side of the RF waveform followed by transport through a magnetic chicane. This approach has at least three flaws: 1) it is difficult to correct aberrations- particularly RF curvature, 2) rising side acceleration exacerbates space charge-induced distortion of the longitudinal phase space, and 3) all achromatic "negative compaction" compressors create parasitic compression during the final compression process, increasing the CSR-induced emittance growth. One can avoid these deficiencies by using acceleration on the falling side of the RF waveform and a compressor with M56>0. This approach offers multiple advantages: 1) It is readily achieved in beam lines supporting simple schemes for aberration compensation, 2) Longitudinal space charge (LSC)-induced phase space distortion tends, on the falling side of the RF waveform, to enhance the chirp, and 3) Compressors with M56>0 can be configured to avoid spurious over-compression. We will discuss this bunch compression scheme in detail and give results of a successful beam test in April 2012 using the JLab UV Demo FEL
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA033
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Paper

Title

Page

Status of the MaRIE X-FEL Accelerator Design

1894

J.W. Lewellen, K. Bishofberger, B.E. Carlsten, L.D. Duffy, F.L. Krawczyk, Q.R. Marksteiner, D.C. Nguyen, S.J. Russell, R.L. Sheffield, N.A. Yampolsky
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the MaRIE program at Los Alamos National Laboratory, under contract DE-AC52-06NA25396
The Matter-Radiation Interactions in Extremes (MaRIE) facility is intended to probe and control the time-dependent properties of materials under extreme conditions. At its core, the “MaRIE 1.0” X-FEL is being designed to deliver pulse trains of ~10¹⁰ 42 keV photons, with a minimum bunch spacing of 2.4 ns, enabling time-dependent studies particularly of mesoscale phenomena. The X-FEL accelerator is also intended to deliver a series of 2 nC electron bunches to enable electron radiography concurrently with the X-ray pulse train, so as to provide multi-probe capability to MaRIE. In 2014, the reference design for the MaRIE X-FEL 12 GeV driver linac was changed from an S-band normal-conducting to an L-band superconducting linac to accommodate pulse trains up to 100 μs in duration. This paper does not present a complete solution for the MaRIE linac design; rather it describes our current reference design, achieved parameters, areas of concern and paths towards mitigation of identified issues.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA026

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPMA033

A Bunch Compression Method for Free Electron Lasers that Avoids Parasitic Compressions

1907

S.V. Benson, D. Douglas, C. Tennant, F.G. Wilson
JLab, Newport News, Virginia, USA
D.C. Nguyen
LANL, Los Alamos, New Mexico, USA

Funding: This work was supported by U.S. DOE Contract No. DE-AC05-84-ER40150, the Air Force Office of Scientific Research, DOE Basic Energy Sciences.
Virtually all existing high energy (>few MeV) linac-driven FELs compress the electron bunch length though the use of off-crest acceleration on the rising side of the RF waveform followed by transport through a magnetic chicane. This approach has at least three flaws: 1) it is difficult to correct aberrations- particularly RF curvature, 2) rising side acceleration exacerbates space charge-induced distortion of the longitudinal phase space, and 3) all achromatic "negative compaction" compressors create parasitic compression during the final compression process, increasing the CSR-induced emittance growth. One can avoid these deficiencies by using acceleration on the falling side of the RF waveform and a compressor with M56>0. This approach offers multiple advantages: 1) It is readily achieved in beam lines supporting simple schemes for aberration compensation, 2) Longitudinal space charge (LSC)-induced phase space distortion tends, on the falling side of the RF waveform, to enhance the chirp, and 3) Compressors with M56>0 can be configured to avoid spurious over-compression. We will discuss this bunch compression scheme in detail and give results of a successful beam test in April 2012 using the JLab UV Demo FEL

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA033

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)