DIPAC2011 - List of Authors (Douglas, D.)

Paper

Title

Page

Bunch Compression, RF Curvature Correction and R₅₅, T₅₅₅ and U₅₅₅₅ Measurements at JLab FEL

15

P. Evtushenko, S.V. Benson, D. Douglas
JLAB, Newport News, Virginia, USA

The JLab IR/UV FEL Upgrade operates with the bunch length compressed down to 100-150 fs RMS. An indispensible part of the bunch compression scheme is the correction of the so-called LINAC RF curvature. Unlike other systems – where the RF curvature gets corrected using higher a harmonic LINAC – our system utilizes magnetic elements of the beam transport system to correct and adjust the second and third order correlation terms. These are expressed in terms of the transport matrix elements T₅₆₆ and U₅₆₆₆. The linear correlation term described by M₅₅ is adjusted using the magnetic system as well. The large energy spread induced on the beam by the FEL operation is compressed as a part of the energy recovery process. As in the case of bunch length compression, this energy compression is optimized by properly adjusting high order transport matrix elements. In this contribution we describe the system used for direct measurements of the transport matrix elements M₅₅, T₅₆₆ and U₅₆₆₆ and its impact on the operation and bunch compression. Results of the measurements are presented together with the bunch length measurements including the data showing resolution and accuracy of the system.

Slides MOOB04 [0.999 MB]

Paper	Title	Page
MOOB04	Bunch Compression, RF Curvature Correction and R₅₅, T₅₅₅ and U₅₅₅₅ Measurements at JLab FEL	15
	P. Evtushenko, S.V. Benson, D. Douglas JLAB, Newport News, Virginia, USA
	The JLab IR/UV FEL Upgrade operates with the bunch length compressed down to 100-150 fs RMS. An indispensible part of the bunch compression scheme is the correction of the so-called LINAC RF curvature. Unlike other systems – where the RF curvature gets corrected using higher a harmonic LINAC – our system utilizes magnetic elements of the beam transport system to correct and adjust the second and third order correlation terms. These are expressed in terms of the transport matrix elements T₅₆₆ and U₅₆₆₆. The linear correlation term described by M₅₅ is adjusted using the magnetic system as well. The large energy spread induced on the beam by the FEL operation is compressed as a part of the energy recovery process. As in the case of bunch length compression, this energy compression is optimized by properly adjusting high order transport matrix elements. In this contribution we describe the system used for direct measurements of the transport matrix elements M₅₅, T₅₆₆ and U₅₆₆₆ and its impact on the operation and bunch compression. Results of the measurements are presented together with the bunch length measurements including the data showing resolution and accuracy of the system.
	Slides MOOB04 [0.999 MB]