DIPAC2011 - List of Keywords (SRF)

Paper	Title	Other Keywords	Page
MOOB04	Bunch Compression, RF Curvature Correction and R₅₅, T₅₅₅ and U₅₅₅₅ Measurements at JLab FEL	FEL, linac, cavity, sextupole	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]

TUPD07	Instrumentation Needs and Solutions for the Development of an SRF Photoelectron Injector at the Energy-Recovery Linac BERLinPro	emittance, gun, laser, cavity	317
	R. Barday, T. Kamps, A. Neumann, J. Rudolph, S.G. Schubert, J. Völker HZB, Berlin, Germany A. Ferrarotto, T. Weis DELTA, Dortmund, Germany
	BERLinPro is an energy-recovery linac for an electron beam with 1 mm mrad normalized emittance and 100 mA average current. The initial beam parameters are determined by the performance of the electron source, an SRF photo-electron injector. Development of this source is a major part of the BERLinPro programme. The instrumentation for the first stage of the programme serves the purpose to have robust and reliable monitors for fundamental beam parameters like emittance, bunch charge, energy and energy spread. The critical issue of the second stage is the generation of an electron beam with 100 mA average current and a normalized emittance of 1 mm mrad. Therefore we plan to setup a dedicated instrumentation beamline with a compact DC gun to measure thermal emittance, current and current lifetime. In parallel an SRF gun with dedicated diagnostics will be build focused on ERL specific aspects like emittance compensation with low-energy beams and reliability of high current operation. This paper collects requirements for each development stage and discusses solutions to specific measurement problems.

TUPD40	Analysis of the Post-mortem Events at the TLS	diagnostics, power-supply, dipole, injection	392
	K.H. Hu, Y.-T. Chang, J. Chen, P.C. Chiu, K.T. Hsu, C.H. Kuo, Y.-H. Lin, Y.R. Pan NSRRC, Hsinchu, Taiwan
	Analyzing the reasons of various trip events are basis to improve reliability of a accelerator system. Understand the mechanisms caused trip of the machine will be very helpful to decide what the adequate measures to improve availability. To identify the causes of trips at Taiwan Light Source (TLS), various diagnostics tool were employed. These diagnostic tools can capture beam trips, interlock signals of superconducting RF system, quench and interlock signals of the superconducting insertion device, waveform of the injection kickers, and instability signals of the stored beam for post-mortem analysis. Various functionalities of trip diagnostic are supported. Available tools and experiences will be summarized in this report.

TUPD50	Slice-Emittance Measurements at ELBE / SRF-Injector	emittance, electron, simulation, quadrupole	416
	J. Rudolph, M. Abo-Bakr, T. Kamps HZB, Berlin, Germany J. Teichert HZDR, Dresden, Germany
	Funding: Supported by the European Community-Research Infrastructure Activity under the FP7 program (EuCARD, contract number 227579) The linear accelerator ELBE delivers high-brightness electron bunches to multiple user stations, including an IR-FEL. The current thermionic injector is being replaced by a superconducting rf photoinjector (SRF-injector) which promises higher beam quality. Using a transfer chicane, beam from the SRF-injector can be injected into the ELBE linac. Detailed characterization of the electron beam is achieved by measuring the vertical slice emittance of the beam. To perform this measurement a combination of rf zero-phasing, spectrometer dipole and quadrupole scan is used. The electron beam is accelerated by the first cavity of the ELBE accelerator module and send through a second cavity which is operated at zero-crossing of the rf. In doing so a linear energy-time correlation is induced to the beam. The chirped beam is send through a spectrometer dipole and the longitudinal distribution can be made visible on a scintillator screen. Performing a quadrupole scan allows the determination of the emittance for different slices. This paper explains the working principle of the method and the experimental setup and shows results of performed simulations as well as first measurement results.

Paper

Title

Other Keywords

Page

MOOB04

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

FEL, linac, cavity, sextupole

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]

TUPD07

Instrumentation Needs and Solutions for the Development of an SRF Photoelectron Injector at the Energy-Recovery Linac BERLinPro

emittance, gun, laser, cavity

317

R. Barday, T. Kamps, A. Neumann, J. Rudolph, S.G. Schubert, J. Völker
HZB, Berlin, Germany
A. Ferrarotto, T. Weis
DELTA, Dortmund, Germany

BERLinPro is an energy-recovery linac for an electron beam with 1 mm mrad normalized emittance and 100 mA average current. The initial beam parameters are determined by the performance of the electron source, an SRF photo-electron injector. Development of this source is a major part of the BERLinPro programme. The instrumentation for the first stage of the programme serves the purpose to have robust and reliable monitors for fundamental beam parameters like emittance, bunch charge, energy and energy spread. The critical issue of the second stage is the generation of an electron beam with 100 mA average current and a normalized emittance of 1 mm mrad. Therefore we plan to setup a dedicated instrumentation beamline with a compact DC gun to measure thermal emittance, current and current lifetime. In parallel an SRF gun with dedicated diagnostics will be build focused on ERL specific aspects like emittance compensation with low-energy beams and reliability of high current operation. This paper collects requirements for each development stage and discusses solutions to specific measurement problems.

TUPD40

Analysis of the Post-mortem Events at the TLS

diagnostics, power-supply, dipole, injection

392

K.H. Hu, Y.-T. Chang, J. Chen, P.C. Chiu, K.T. Hsu, C.H. Kuo, Y.-H. Lin, Y.R. Pan
NSRRC, Hsinchu, Taiwan

Analyzing the reasons of various trip events are basis to improve reliability of a accelerator system. Understand the mechanisms caused trip of the machine will be very helpful to decide what the adequate measures to improve availability. To identify the causes of trips at Taiwan Light Source (TLS), various diagnostics tool were employed. These diagnostic tools can capture beam trips, interlock signals of superconducting RF system, quench and interlock signals of the superconducting insertion device, waveform of the injection kickers, and instability signals of the stored beam for post-mortem analysis. Various functionalities of trip diagnostic are supported. Available tools and experiences will be summarized in this report.

TUPD50

Slice-Emittance Measurements at ELBE / SRF-Injector

emittance, electron, simulation, quadrupole

416

J. Rudolph, M. Abo-Bakr, T. Kamps
HZB, Berlin, Germany
J. Teichert
HZDR, Dresden, Germany

Funding: Supported by the European Community-Research Infrastructure Activity under the FP7 program (EuCARD, contract number 227579)
The linear accelerator ELBE delivers high-brightness electron bunches to multiple user stations, including an IR-FEL. The current thermionic injector is being replaced by a superconducting rf photoinjector (SRF-injector) which promises higher beam quality. Using a transfer chicane, beam from the SRF-injector can be injected into the ELBE linac. Detailed characterization of the electron beam is achieved by measuring the vertical slice emittance of the beam. To perform this measurement a combination of rf zero-phasing, spectrometer dipole and quadrupole scan is used. The electron beam is accelerated by the first cavity of the ELBE accelerator module and send through a second cavity which is operated at zero-crossing of the rf. In doing so a linear energy-time correlation is induced to the beam. The chirped beam is send through a spectrometer dipole and the longitudinal distribution can be made visible on a scintillator screen. Performing a quadrupole scan allows the determination of the emittance for different slices. This paper explains the working principle of the method and the experimental setup and shows results of performed simulations as well as first measurement results.