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Paul Scherrer Institut PSI Accelerator Development and Operation Support

Paul Scherrer Institut
5232 Villigen PSI, Schweiz/Switzerland
Tel. +41 56 310 21 11
Fax. +41 56 310 21 99

E-Mail: andreas.streun@psi.ch

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SLS Internal Reports 2002


M.Munoz, M.Boege, J.Chrin, A.Streun

Experience during the SLS commissioning

ICAP 2002, East Lansing, USA, 15-18 October 2002, 12-NOV-2002, 6 pages [PS] [PDF]

During the commissioning and first years of SLS operations we have made extensive use of an accelerator machine model. The model is based on a C port of the original TRACY-2 Pascal code. This model is connected to the applications in the control room through a CORBA interface. This approach has facilitated easy integration of the accurate machine model with the operation of the machine, and allows us to use the well-tested TRACY-2 procedures online. A good example of this approach is the orbit correction system, but several other utilities have also been developed.


M.Boege, J.Chrin

Making a Statement with CORBA

PCaPAC 2002, Frascati, Italy, 14-17 October 2002, 7-OCT-2002, 3 pages [PS] [PDF]

An interface to the Oracle relational database management system (RDBMS), implemented using the Common Object Request Broker Architecture (CORBA), provides clients with a set of methods that execute Structured Query Language (SQL) statements and return result sets within the context of a CORBA object. The database server-client framework is presented, including a description of the CORBA object to relational database mapping scheme.


J.Chrin, C. Beny, M. Boege, M.Grunder, M.Janousch, R.Krempaska, M.Munoz, A.Streun

Corba Experience at the SLS

CORBA Controls Workshop, ESRF, Grenoble, 9-11 October 2002, 18-SEP-2002, 5 pages [PS] [PDF]

Beam dynamics applications and components of the beamline experimental controls system at the Swiss Light Source (SLS) have benefitted from a distributed and heterogeneous computing environment in which the Common Object Request Broker Architecture (CORBA) forms the middleware layer and access point to essential software packages. Use is made of CORBA methods provided by the Portable Object Adapter (POA) for accessing ORB functions, such as object reactivation and object persistence, the Implementation Repository (IMR) for the automatic reactivation of servers, and the CORBA Event Service for the propagation of controls and physics data. An account of the experience gained, in the three years since development work began to the present time of first SLS operation, is presented.



Global Position Feedback in SR Sources

EPAC02, Paris, June 2002, 12-AUG-2002, 5 pages [PS] [PDF]

Beam stability and orbit control represent key issues for SR sources as user facilities. The continuous reduction of emittance and coupling as well as the increasing sophistication of experiments lead to more and more stringent requirements for beam stability and reproducibility of golden orbits down to a micrometer or even sub-micrometer level. Most SR sources have therefore implemented local or global position feedback systems covering a frequency range from DC to 200 Hz. Key elements of position feedback systems such as pick-ups, correctors, electronics and processing hardware as well as correction algorithms and techniques are presented. Their properties and suitability regarding the character of orbit disturbances, user requirements and feedback loop characteristics are analyzed. Examples and achievements of (global) position feedback systems in various SR facilities are presented.


A.Luedeke, M.Munoz

Top-Up Operation at the SLS

EPAC02, Paris, June 2002, 9-AUG-2002, 3 pages [PS] [PDF]

The Swiss Light Source (SLS) is a medium energy 3rd generation light source, optimized for mini-gap undulators. A Touschek dominated beam life time of 3.5 h is expected for the design current of 400 mA in the presence of undulators with 4 mm full gap size.Therefore a continuous refilling of beam-current, the so called top-up operation, is a prerequisite for most user operation. This mode was used successfully already in early commissioning and has been the standard mode for user operation for the last year. The gained experience will be described in this paper.



Experience with the SLS Booster

EPAC02, Paris, June 2002, 9-AUG-2002, 3 pages [PS] [PDF]

The Swiss Light Source (SLS) uses a new approach in the design of the booster synchrotron. The results of the commissioning and operation phases are described, and in particular some of the anticipated difficulties (effect in the storage ring, lifetime at low energy) and how they were solved.


S.C.Leemann, M.Bvge, M.Dehler, V.Schlott, A.Streun

Precise Beam Energy Calibration at the SLS Storage Ring

EPAC02, Paris, June 2002, 9-AUG-2002, 3 pages [PS] [PDF] [HTML]

In addition to precise dipole field measurements the method of resonant electron spin depolarization can be utilized to determine the average beam energy with high precision. Estimates for the expected equilibrium polarization level in the SLS storage ring are presented together with polarization rise-time measurements observing the polarization dependent Touschek scattering limited lifetime. Results from resonant spin depolarization and nonlinear momentum compaction factor measurements are presented.


M.Boege, J.Chrin, P.Pollet, T.Schilcher, V.Schlott

Orbit Control at the SLS Storage Ring

EPAC02, Paris, June 2002, 9-AUG-2002, 3 pages [PS] [PDF] [HTML]

Precise orbit control is one of the crucial ingredients for stable operation of the SLS storage ring. The orbits are taken by the digital BPM system which allows beam position measurements to the sub-micron level at sampling rates of up to 4 kHz at 72 locations in the ring. Orbits are corrected with respect to a user defined reference by applying SVD techniques and a direct response matrix inversion. A slow global orbit feedback operating at correction rates of up to 1 Hz stabilizes the orbit to within 0.5 m rms at the locations of the insertion devices. Energy drifts are automatically corrected using the RF frequency as an additional corrector, resulting in a long term energy stability of (dP/P)~10^-5. The status of a digital BPM system based fast orbit feedback running at 4 kHz sampling rate is presented.


M.Boege, A.Streun, V.Schlott

Measurement and Correction of Imperfections in the SLS Storage Ring

EPAC02, Paris, June 2002, 9-AUG-2002, 3 pages [PS] [PDF] [HTML]

Based on precise average beta function measurements with errors of 1 % for the locations of the 174 quadrupoles an SVD based beta beat correction has been applied using the individually powered quadrupoles as correctors. Residual horizontal and vertical beta beats of 4 and 3 % have been measured after correction. Beam based alignment techniques have been applied to determine BPM centers with respect to adjacent quadrupoles.



First Operation of the Swiss Light Source

EPAC02, Paris, June 2002, 9-AUG-2002, 5 pages [PS] [PDF]

(o The Swiss Light Source (SLS) at the Paul Scherrer Institute (PSI) is the most recent 3rd generation light source to be commissioned. It consists of a 100 MeV linac, a novel type of full energy booster synchrotron and a 12-TBA storage ring of 288 m circumference providing 5 nm rad natural emittance at 2.4 GeV. The SLS project was approved by the Swiss Government in September 1997. Commissioning of the SLS began in January 2000 and was successfully completed to within design specifications in August 2001. 70 % of beam time has since been dedicated to the operation of the first four beamlines. Key design features are reviewed and the main commissioning results presented, including that of innovative subsystems such as the digital BPM system, the digital power supplies, the high stability injection system and the first insertion devices. A report on the initial operation experience is also given.



Some design considerations for the SLS-FEMTO insertion (DRAFT)

26-APR-2002, 28 pages [PDF]



SLS booster-to-storage ring transferline optics for optimum injection efficiency

7-FEB-2002, 10 pages [PDF]



Specifications of photon beam position monitors for SLS bending magnet beamlines

1-FEB-2002, 19 pages

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