LINAC2014 - List of Authors (Thangaraj, J.C.T.)

Paper	Title	Page
MOPP058	Z-slicer: A Simple Scheme for Electron Beam Current Profile Shaping in a Linac	183
	J.C.T. Thangaraj, C.M. Baffes, D.R. Broemmelsiek, D.J. Crawford, R.M. Thurman-Keup Fermilab, Batavia, Illinois, USA W.B. Wortley University of Rochester, Rochester, New York, USA
	Short bunches are a premium at accelerator facilities and their applications include THz generation, short bunch production, shaped bunch production, etc. In this work we report on the design of an experiment involving an electron beam about 50 MeV that will be intercepted by a set of metallic slits inside a bunch compressor. After the mask, some electrons are scattered while other pass through un-affected. After exiting the bunch compressor, those electrons that were not affected by the slits will appear as short electron bunches. The key advantage of our scheme is its simplicity, tunability and low cost. The scheme does not require any additional hardware such as lasers, undulator, transverse deflecting cavity. The tuning variable is only the RF-chirp and detection of the bunching requires just a skew quad in the chicane and a transverse screen downstream. A thermal analysis suggests that MHz operation of the linac can be sustained under certain beam conditions without any damage to the slit mask.

THPP058	A Review of Emittance Exchanger Beamlines: Past Experiments and Future Proposals	982
THPOL12	use link to see paper's listing under its alternate paper code
	J.C.T. Thangaraj Fermilab, Batavia, Illinois, USA
	Emittance exchangers (EEX) are advanced phase space manipulation schemes where the transverse phase space of the electron beam is exchanged with the longitudinal phase space. The first experimentally demonstrated concept of the emittance exchanger at the A0 photoinjector at Fermilab used a transverse deflecting cavity (TDC) sandwiched between two doglegs. In this talk, I will briefly review the history of the emittance exchange beamline experiments from a low charge beam without RF chirp to a high charge beam with RF chirp including collective effects such as coherent synchrotron radiation. I will also describe how shaping application have been spawned based on EEX. I will then review future schemes that has been proposed and propose two additional schemes of EEX that can be implemented in existing modern linacs. As an example, we present an improved emittance exchanger scheme that uses a TDC sandwiched between two chicanes. The significant advantage of this scheme is that it allows the use of the expensive transverse deflecting cavity for diagnostics and still allows the flexibility to use the existing beamline either as a bunch compressor or an emittance exchanger.

THPP059	Z-Shaper: A Picosecond UV Laser Pulse Shaping Channel at the Advanced Superconducting Test Accelerator	986
	J.C.T. Thangaraj, D.R. Edstrom, A.H. Lumpkin, J. Ruan Fermilab, Batavia, Illinois, USA B. Beaudoin UMD, College Park, Maryland, USA
	Many accelerator applications require a longitudinally shaped electron beam profile for studies ranging from THz generation to dielectric wakefield acceleration. An electron beam profile can be shaped through many techniques in both electron beam generation, such as with a DAZZLER or in ellipsoidal pulse generation, and beam transport, using an emittance exchanger or linearizing harmonic cavity. In this paper, shaping of a UV pulse with length on the order of picoseconds is examined using alpha-BBO crystals in the Advanced Superconducting Test Accelerator (ASTA) drive laser. A relatively economical solution to effect a predictable and tunable longitudinal bunch shape, profiles have been generated and observed using a Hamamatsu C5680 streak camera, and the results are compared with the analytical theory.

Paper

Title

Page

Z-slicer: A Simple Scheme for Electron Beam Current Profile Shaping in a Linac

183

J.C.T. Thangaraj, C.M. Baffes, D.R. Broemmelsiek, D.J. Crawford, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA
W.B. Wortley
University of Rochester, Rochester, New York, USA

Short bunches are a premium at accelerator facilities and their applications include THz generation, short bunch production, shaped bunch production, etc. In this work we report on the design of an experiment involving an electron beam about 50 MeV that will be intercepted by a set of metallic slits inside a bunch compressor. After the mask, some electrons are scattered while other pass through un-affected. After exiting the bunch compressor, those electrons that were not affected by the slits will appear as short electron bunches. The key advantage of our scheme is its simplicity, tunability and low cost. The scheme does not require any additional hardware such as lasers, undulator, transverse deflecting cavity. The tuning variable is only the RF-chirp and detection of the bunching requires just a skew quad in the chicane and a transverse screen downstream. A thermal analysis suggests that MHz operation of the linac can be sustained under certain beam conditions without any damage to the slit mask.

THPP058

A Review of Emittance Exchanger Beamlines: Past Experiments and Future Proposals

982

THPOL12

use link to see paper's listing under its alternate paper code

J.C.T. Thangaraj
Fermilab, Batavia, Illinois, USA

Emittance exchangers (EEX) are advanced phase space manipulation schemes where the transverse phase space of the electron beam is exchanged with the longitudinal phase space. The first experimentally demonstrated concept of the emittance exchanger at the A0 photoinjector at Fermilab used a transverse deflecting cavity (TDC) sandwiched between two doglegs. In this talk, I will briefly review the history of the emittance exchange beamline experiments from a low charge beam without RF chirp to a high charge beam with RF chirp including collective effects such as coherent synchrotron radiation. I will also describe how shaping application have been spawned based on EEX. I will then review future schemes that has been proposed and propose two additional schemes of EEX that can be implemented in existing modern linacs. As an example, we present an improved emittance exchanger scheme that uses a TDC sandwiched between two chicanes. The significant advantage of this scheme is that it allows the use of the expensive transverse deflecting cavity for diagnostics and still allows the flexibility to use the existing beamline either as a bunch compressor or an emittance exchanger.

THPP059

Z-Shaper: A Picosecond UV Laser Pulse Shaping Channel at the Advanced Superconducting Test Accelerator

986

J.C.T. Thangaraj, D.R. Edstrom, A.H. Lumpkin, J. Ruan
Fermilab, Batavia, Illinois, USA
B. Beaudoin
UMD, College Park, Maryland, USA

Many accelerator applications require a longitudinally shaped electron beam profile for studies ranging from THz generation to dielectric wakefield acceleration. An electron beam profile can be shaped through many techniques in both electron beam generation, such as with a DAZZLER or in ellipsoidal pulse generation, and beam transport, using an emittance exchanger or linearizing harmonic cavity. In this paper, shaping of a UV pulse with length on the order of picoseconds is examined using alpha-BBO crystals in the Advanced Superconducting Test Accelerator (ASTA) drive laser. A relatively economical solution to effect a predictable and tunable longitudinal bunch shape, profiles have been generated and observed using a Hamamatsu C5680 streak camera, and the results are compared with the analytical theory.