IPAC2011 - List of Authors (Streun, A.)

Paper	Title	Page
THPC061	Comparison of Linear Optics Correction Means at the SLS	3032
	M. Aiba, M. Böge, J.T.M. Chrin, N. Milas, T. Schilcher, A. Streun PSI, Villigen, Switzerland
	The experimental determination of linear optics is a fundamental prerequisite to achieving a high performance storage ring. In order to further enhance SLS performance and to simulataneously reveal the limitations of the various techniques, we perform a systematic study of linear optics optimization using various independent methods. These include an analysis of the orbit reponse (LOCO), turn-by-turn data, and the response of the tune, whose correction is accomplished using the standard SLS procedure of varying the quadrupole strengths. A comparison of results from these procedures, which use fully independent observables, provides us with a valuable cross-check. For example, the betatron phase advances between BPMs, which is independent of BPM calibration, confirms the optics correction as determined from LOCO. The linear optics are hence better optimized, and these procedures, LOCO in particular, further serve to expose any previously hidden mis-calibration of parameters e.g. from BPMs and corrector magnets. Systematic errors from turn-by-turn data could also be vastly reduced by a better synchronization of the BPM triggers with the electron beam.

THPC062	SLS Vertical Emittance Tuning	3035
	M. Böge, M. Aiba, N. Milas, A. Streun PSI, Villigen, Switzerland S.M. Liuzzo INFN/LNF, Frascati (Roma), Italy
	To establish ultra-small vertical emittances (<1pmrad @2.86GeV) is one important aim of future linear collider damping ring optimization studies* at the SLS. By utilizing various correction techniques the SLS is already close to this goal with emittances of <2pm.rad @2.4GeV under the constraint of maintaining user operation conditions. One of the limiting contributions is the remaining spurious vertical dispersion eta_y of ~1.4mm which can be reduced by careful re-alignment and the application of dispersion-free steering techniques. The latter require orbit manipulations which are only partially compatible with the user operation mode. A first application of dispersion-free steering techniques demonstrates that eta_y can be reduced to <1mm at the expense of large orbit excursions which require a simultaneous betatron-coupling correction by means of skew quadrupoles in order to benefit in terms of a further reduction of vertical emittance. Therefore possible girder and magnet misalignments are analyzed in simulation which allows to localize the sources of eta_y and to eliminate them by re-alignment. Following this path the goal to achieve emittances close to 1pmrad is within reach. * In January 2011 the EU-project TIARA (Test Infrastructure and Accelerator Research Area) started with contributions from the SLS as part of the SVET (SLS Vertical Emittance Tuning) work package WP6.

Paper

Title

Page

Comparison of Linear Optics Correction Means at the SLS

3032

M. Aiba, M. Böge, J.T.M. Chrin, N. Milas, T. Schilcher, A. Streun
PSI, Villigen, Switzerland

The experimental determination of linear optics is a fundamental prerequisite to achieving a high performance storage ring. In order to further enhance SLS performance and to simulataneously reveal the limitations of the various techniques, we perform a systematic study of linear optics optimization using various independent methods. These include an analysis of the orbit reponse (LOCO), turn-by-turn data, and the response of the tune, whose correction is accomplished using the standard SLS procedure of varying the quadrupole strengths. A comparison of results from these procedures, which use fully independent observables, provides us with a valuable cross-check. For example, the betatron phase advances between BPMs, which is independent of BPM calibration, confirms the optics correction as determined from LOCO. The linear optics are hence better optimized, and these procedures, LOCO in particular, further serve to expose any previously hidden mis-calibration of parameters e.g. from BPMs and corrector magnets. Systematic errors from turn-by-turn data could also be vastly reduced by a better synchronization of the BPM triggers with the electron beam.

THPC062

SLS Vertical Emittance Tuning

3035

M. Böge, M. Aiba, N. Milas, A. Streun
PSI, Villigen, Switzerland
S.M. Liuzzo
INFN/LNF, Frascati (Roma), Italy

To establish ultra-small vertical emittances (<1pmrad @2.86GeV) is one important aim of future linear collider damping ring optimization studies* at the SLS. By utilizing various correction techniques the SLS is already close to this goal with emittances of <2pm.rad @2.4GeV under the constraint of maintaining user operation conditions. One of the limiting contributions is the remaining spurious vertical dispersion eta_y of ~1.4mm which can be reduced by careful re-alignment and the application of dispersion-free steering techniques. The latter require orbit manipulations which are only partially compatible with the user operation mode. A first application of dispersion-free steering techniques demonstrates that eta_y can be reduced to <1mm at the expense of large orbit excursions which require a simultaneous betatron-coupling correction by means of skew quadrupoles in order to benefit in terms of a further reduction of vertical emittance. Therefore possible girder and magnet misalignments are analyzed in simulation which allows to localize the sources of eta_y and to eliminate them by re-alignment. Following this path the goal to achieve emittances close to 1pmrad is within reach.
* In January 2011 the EU-project TIARA (Test Infrastructure and Accelerator Research Area) started with contributions from the SLS as part of the SVET (SLS Vertical Emittance Tuning) work package WP6.