FEL2011 - List of Keywords (monitoring)

Paper	Title	Other Keywords	Page
WEPA02	Thermal Acoustic Sensor for High Pulse Energy X-ray FEL Beams	target, FEL, photon, radiation	334
	T.J. Smith, J.C. Frisch, E.M. Kraft, J. Loos SLAC, Menlo Park, California, USA G.S. Bentsen Rochester University, Rochester, New York, USA
	Funding: Work supported by Department of Energy Contract DE AC03 76SF00515 The pulse energy density of X-ray FELs will saturate or destroy conventional X-ray diagnostics, and the use of large beam attenuation will result in a beam that is dominated by harmonics. We present results at the LCLS from using a pulse energy detector based on the thermal acoustic effect. In this type of detector an X-ray resistant material (Boron Carbide for this system) intercepts the beam. The pulse heating of this material produces an acoustic pulse that can be detected with high frequency microphones to produce a signal that is linear in the absorbed energy.

WEPB04	Position Stability Monitoring of the LCLS Undulator Quadrupoles	undulator, quadrupole, controls, ground-motion	398
	H.-D. Nuhn, G.L. Gassner, F. Peters SLAC, Menlo Park, California, USA
	Funding: This work was supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515 In the era of SASE FELs, the demand for position stability of undulator components scales down to the range of sub-micrometers per day. Simultaneously, the undulator length increases significantly, in order to reach X-ray wavelengths. To minimize the impact of the outside environment, the LCLS undulator is placed underground, but reliable data about ground motion inside such a tunnel were not available in the required stability range. Therefore, a new position monitor system has been developed and installed for the LCLS undulator. That system is capable to measure X-, Y- and Roll positions of each of the 33 undulator quadrupoles, with respect to stretched wires. Instrument resolution is about 20 nm and instrument drift is negligible small. Position data of individual quadrupoles can be correlated along the entire undulator, which has a length of 132 m. The system is under continuous operation since 2009. The report describes long term experience with the running system and the observed position stability of the undulator quadrupoles.

THPA10	RF Photo Gun Stability Measurement at PITZ	gun, laser, feedback, cathode	485
	I.I. Isaev, G. Asova, H.-J. Grabosch, M. Groß, L. Hakobyan, Ye. Ivanisenko, G. Klemz, W. Köhler, M. Krasilnikov, M. Mahgoub, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, S. Rimjaem, F. Stephan, G. Vashchenko, S. Weidinger, R.W. Wenndorff DESY Zeuthen, Zeuthen, Germany M. Hoffmann, H. Schlarb DESY, Hamburg, Germany M.A. Khojoyan ANSL, Yerevan, Armenia D. Richter BESSY GmbH, Berlin, Germany A. Shapovalov MEPhI, Moscow, Russia
	High stability of the RF photo gun is one of the necessary conditions for the successful operation of linac based free electron lasers. Fluctuations of the RF launch phase have significant influence on the beam quality. Investigation on the dependence of different gun parameters and selection of optimal conditions are required to achieve high RF gun phase stability. Measurements of the gun RF phase stability are based on beam charge and momentum monitoring downstream of the gun. The stability of the RF gun phase for different operating conditions has been measured at the Photo Injector Test facility at DESY in Zeuthen (PITZ) and the results will be presented.

Paper

Title

Other Keywords

Page

WEPA02

Thermal Acoustic Sensor for High Pulse Energy X-ray FEL Beams

target, FEL, photon, radiation

334

T.J. Smith, J.C. Frisch, E.M. Kraft, J. Loos
SLAC, Menlo Park, California, USA
G.S. Bentsen
Rochester University, Rochester, New York, USA

Funding: Work supported by Department of Energy Contract DE AC03 76SF00515
The pulse energy density of X-ray FELs will saturate or destroy conventional X-ray diagnostics, and the use of large beam attenuation will result in a beam that is dominated by harmonics. We present results at the LCLS from using a pulse energy detector based on the thermal acoustic effect. In this type of detector an X-ray resistant material (Boron Carbide for this system) intercepts the beam. The pulse heating of this material produces an acoustic pulse that can be detected with high frequency microphones to produce a signal that is linear in the absorbed energy.

WEPB04

Position Stability Monitoring of the LCLS Undulator Quadrupoles

undulator, quadrupole, controls, ground-motion

398

H.-D. Nuhn, G.L. Gassner, F. Peters
SLAC, Menlo Park, California, USA

Funding: This work was supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515
In the era of SASE FELs, the demand for position stability of undulator components scales down to the range of sub-micrometers per day. Simultaneously, the undulator length increases significantly, in order to reach X-ray wavelengths. To minimize the impact of the outside environment, the LCLS undulator is placed underground, but reliable data about ground motion inside such a tunnel were not available in the required stability range. Therefore, a new position monitor system has been developed and installed for the LCLS undulator. That system is capable to measure X-, Y- and Roll positions of each of the 33 undulator quadrupoles, with respect to stretched wires. Instrument resolution is about 20 nm and instrument drift is negligible small. Position data of individual quadrupoles can be correlated along the entire undulator, which has a length of 132 m. The system is under continuous operation since 2009. The report describes long term experience with the running system and the observed position stability of the undulator quadrupoles.

THPA10

RF Photo Gun Stability Measurement at PITZ

gun, laser, feedback, cathode

485

I.I. Isaev, G. Asova, H.-J. Grabosch, M. Groß, L. Hakobyan, Ye. Ivanisenko, G. Klemz, W. Köhler, M. Krasilnikov, M. Mahgoub, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, S. Rimjaem, F. Stephan, G. Vashchenko, S. Weidinger, R.W. Wenndorff
DESY Zeuthen, Zeuthen, Germany
M. Hoffmann, H. Schlarb
DESY, Hamburg, Germany
M.A. Khojoyan
ANSL, Yerevan, Armenia
D. Richter
BESSY GmbH, Berlin, Germany
A. Shapovalov
MEPhI, Moscow, Russia

High stability of the RF photo gun is one of the necessary conditions for the successful operation of linac based free electron lasers. Fluctuations of the RF launch phase have significant influence on the beam quality. Investigation on the dependence of different gun parameters and selection of optimal conditions are required to achieve high RF gun phase stability. Measurements of the gun RF phase stability are based on beam charge and momentum monitoring downstream of the gun. The stability of the RF gun phase for different operating conditions has been measured at the Photo Injector Test facility at DESY in Zeuthen (PITZ) and the results will be presented.