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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 2001



Beam Lifetime in the SLS storage ring

19-DEC-2001, 13 pages [PS] [PDF]

Three shifts in Nov. and Dec. 2001 were spent on beam lifetime measurements. Elastic gas scattering was measured by moving scrapers into the beam. Touschek lifetime was measured as function of single bunch current, RF voltage and tune. Analysis of Touschek lifetime provided information on the energy acceptance and its limitation due to a sextupolar resonance, and on the value of emittance coupling. Indications for turbulent bunch lengthening were found and evaluated to estimate the longitudinal broad band impedance.



Measurement of Electron Beam Parameters of the SLS Injection Accelerators

ETHZ-IPP Internal Report 2001-06 (Diploma Thesis), 1-SEP-2001, 46 pages [PDF]



Stainless Steel Vacuum Chambers

SSILS01, Shanghai, Sept. 2001, 1-SEP-2001, 5 pages [PDF]

The vacuum properties of stainless steel are excellent. The fabrication and welding process can be handled easily by a large number of vacuum manufacturers. In particular, the use for intermediate energy light sources gives a lot of advantages, which leads to a cost effective and industrial vacuum system design. Several design solutions are compared in this paper. The common fabrication and vacuum conditioning processes are discussed.


A.Streun, M. Böge, M. Dehler, R. Kramert, L. Rivkin, M. Rohrer, T. Schilcher, V. Schlott, L. Schulz, F. Wei, P. Wiegand, S. Zelenika (Paul Scherrer Institut, CH-5234 Villigen, Switzerland) R. Ruland (SLAC, Menlo Park, USA) E. Meier (Ingenieurbüro Meier, Winterthur, Switzerland)

Beam Stability and Dynamic Alignment at SLS

SSILS01, Shanghai, Sept. 2001, 1-SEP-2001, 5 pages [PDF]

Long and short term stability of the electron beam in the storage ring of the Swiss Light Source (SLS) is achieved by dynamic alignment systems and by fast closed orbit feedback. Quadrupoles, sextupoles and BPMs are rigidly mounted on girders, while the bending magnets are bridging adjacent girders. Positioning of the girders is performed by mover systems based on excenters and encoders. The girder positions are monitored by a hydrostatic leveling system and a digital encoder based horizontal positioning system. Another encoder based system for controlling the BPM positions relative to adjacent quadrupoles is calibrated by beam based alignment. Residual noise of the electron beam has been estimated by investigation of seismic spectra, girder eigenfrequencies, beam amplification factors and capabilities of the fast orbit feedback system. We will describe the systems, summarize the status by September 2001 and show first results.


Andreas Streun, Michael Böge, Micha Dehler, Christopher Gough, Werner Joho, Timo Korhonen, Andreas Lüdeke, Patrick Marchand, Marc Muñoz, Marco Pedrozzi, Leonid Rivkin, Thomas Schilcher, Volker Schlott, Lothar Schulz, Albin Wrulich

Commissioning of the Swiss Light Source

SSILS 01, Shanghai, Sept. 2001, 1-SEP-2001, 5 pages [PDF]

The Swiss Light Source SLS at PSI has started user operation by August 1, 2001. Here we report on the status of commissioning by September 2001: Linac and booster are operational at design performance. The storage ring commissioning has reached the essential design parameters by June 2001: Energy, emittance, current and lifetime according to specifications have been achieved. Top-up injection and transverse multi-bunch feedback are operational. Ongoing commissioning activities concern suppression of an instability, which is probably related to ion trapping, and minimisation of emittance coupling.


G.Ingold, A. Streun, B. Singh, R. Abela, P. Beaud, G. Knopp, L. Rivkin, V. Schlott, Th. Schmidt, H. Sigg, J.F. van der Veen, A. Wrulich (Paul Scherrer Institut, Villigen, Switzerland) S. Khan (BESSY, Berlin, Germany)

Sub-picosecond optical pulses at the SLS storage ring

PAC01,Chicago, June 2001, 1-JUN-2001, 3 pages [PDF]

We report on the feasibility and expected performance of a sub-picosecond X-ray source at the Swiss Light Source (SLS), based on the electron-beam slicing method. This method has recently been demonstrated at the Advanced Light Source (ALS), using a bending magnet to produce ultrafast optical pulses. To improve the flux of such a source for user experiments, we have studied its realization both in the hard and soft X-ray regime, employing small gap insertion devices (IDs) installed either in one or in two successive straight sections. The most favourable geometry is one in which the modulator and the radiator are positioned in the same straight section of the storage ring.


A.Streun, M. Boege, M. Dehler, C. Gough, W. Joho, T. Korhonen, A. Luedeke, P. Marchand, M. Munoz, M. Pedrozzi, L. Rivkin, T. Schilcher, V. Schlott, L. Schulz, A. Wrulich

Commissioning of the Swiss Light Source

PAC 01. June 2001, Chicago, 1-JUN-2001, 3 pages [PDF]

The Swiss Light Source (SLS) at the Paul Scherrer Institute (PSI) consists of a turn key 100 MeV linac, a novel type of booster synchrotron and a 12-TBA storage ring providing 5 nm rad natural emittance at 2.4 GeV. The SLS project was approved by Swiss Government in Sept. 1997. By June 1999 the building was finished. Linac and booster commissioning concluded by April, resp. Sept. 2000. First beam in the ring was stored Dec. 15, 2000. By June 2001 storage ring commissioning entered the final phase: The design current of 400 mA was reached, an excellent agreement of lattice functions with design calculations was achieved and first undulator spectra were measured. Commissioning of booster and storage ring included commissioning of the innovative subsystems like the digital BPM system, the digital power supplies, the high stability injection system and the CORBA based beam dynamics software.


M.Boege, J.Chrin

On the Use of CORBA in High Level Software Applications at the SLS

ICALEPCS 2001, November 2001, 1-NOV-2001, 3 pages [PS] [PDF] [HTML]

Beam dynamics applications at the Swiss Light Source (SLS) have benefitted from a distributed computing environment in which the Common Object Request Broker Architecture (CORBA) forms the middleware layer and access point to several different software components. A suite of remote CORBA server objects provides the client with a convenient and uniform interface to the CDEV (Common DEVice) controls library, the TRACY accelerator physics package, the Oracle database, and an event-logging facility. Use is made of methods provided by the CORBA Portable Object Adaptor for accessing ORB functions, such as object activation and object persistence, the Implementation Repository for the automatic reactivation of servers, and the CORBA Event Service for the propagation of controls and physics data. An account of the CORBA framework, as used by applications in the commissioning and first operation of the SLS, is presented.


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

Commissioning of the SLS using CORBA Based Beam Dynamics Applications

PAC 2001, June 2001, 1-NOV-2001, 3 pages [PS] [PDF] [HTML]

A distributed client-server model, based on the Common Object Request Broker Architecture (CORBA), has been established to interface beam dynamics applications at the Swiss Light Source (SLS) to essential software packages such as the accelerator physics package TRACY and the Common DEVice (CDEV) control library. Within this model remote clients can invoke computer intensive methods, such as beam orbit correction procedures, on a dedicated server. Access to the SLS accelerator devices is achieved through a generic C++ CDEV server. CORBA based applications have been extensively used during the commissioning of the SLS booster and storage ring. It has been demonstrated that the complex client-server environment is manageable and reliable. The inherent flexibility and the relative ``ease of use of the established framework have justified the initial investment in its design and implementation. Beam dynamics related commissioning results are presented together with the corresponding applications.



SLS storage ring non-linear dynamics with FEMTO insertion in one straight section

1-OCT-2001, 26 pages [PDF]

The SLS FEMTO insertions for generation of sub-picosecond X-ray pulses at SLS is under preparation and expected to come into operation early 2004. The most promising layout consists of two insertion devices in the 5L long straight section, the modulator, a high field wiggler, surrounded by a chicane, and the radiator, a mini-gap undulator. Interaction with a laser in the modulator would create the energy modulated sub picosecond satellite beams, and due to the chicane they are spatially separated by dispersion in the radiator. Since the devices operate at relatively large horizontal betafunctions, there was some concern, that the dynamic aperture of the storage ring could be affected by the non-linearity of the magnetic fields or by field errors....



FEMTO: Preliminary studies on effects of background electron pulses

1-OCT-2001, 5 pages [PDF]



FEMTO: Modification of Layout

1-OCT-2001, 9 pages [PDF]



Sensitivity of tunes on length and fringing fields of quadrupoles

1-OCT-2001, 8 pages [PDF]



Some SLS Working Points with lower beta_z in the bending magnets

1-OCT-2001, 12 pages [PDF]



A General Top-Up Equation

23-OCT-2001, 3 pages [PDF]



Limits for normal and skew sextupole and octupole field errors in the first and second field Integrals of Insertion Devices

1-JAN-2001, 13 pages [PDF]



Effects of insertion devices on the beam dynamics of SLS

1-JAN-2001, 38 pages [PDF]

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