Two variable polarization undulators (EU62 and EU71) have been designed and constructed in collaboration between CELLS and Sincrotrone Trieste [1]. EU62 (figures 1 and 2) has been completely assembled and tested while EU71 is now under final magnetic assembling. In this paper the magnetic (EU62) and mechanical performances (EU62, EU72) are summarized. The main characteristics of the control system are also presented. Field optimization techniques are described, showing the achieved performance (EU62) in terms of phase, trajectory and field integral errors. MECHANICAL DESIGN AND PERFORMANCE The mechanical design was developed taking into account the forces, the maximum overall dimensions and the total weight of the structure [1]. Special attention was given to the anti-parallel mode, which generates a strong longitudinal force on the upper/lower beams. The mechanical design is based on the similar design proposed for the Soleil-France undulators [2]. Main mechanical components were manufactured by local companies under Sincrotrone Trieste supervision. The size of the stainless steel beams, the dimensions of the supporting brackets and of the frame truss elements were calculated by 3D FEM calculations taking into account a safety margin of about 20% with respect to the estimated magnetic forces. To test the transverse deformation and validate the design of the phase shifting mechanism, a dedicated tool equipped with load cells and gauges was designed and constructed (see figure 3). This device is able to simulate positive and negative magnetic transverse forces distributed along the beam structure and measure the transverse deformation as a function of the applied force. All the measurements carried out with an applied load of 20% larger than the estimated magnetic forces showed deformations of less than 20 μm. Magnet blocks are clamped on individual holders and grouped in modules containing either three or five magnets by means of small aluminium bars. The modules are precisely positioned on a base-plate acting as an interface with the stainless steel beams. By interposition of calibrated brass shims, small horizontal and/or vertical displacement of each block is allowed in order to compensate magnetic field imperfections. After magnet assembly, detailed mechanical measurements were carried out with the final magnetic load applied (EU62), at minimum gap (15.5mm) and in both parallel and antiparallel modes. Figure 1: EU62 undulator. The measurements performed in parallel (antiparallel) mode showed transverse/longitudinal deformations of the stainless steel beams supporting the magnetic arrays of less than 20/20 (20/75) μm. All the measured deformations were in agreement with the FEM 3D calculation. Figure 2: EU62 in antiparallel mode.

The vacuum system of CELLS is in the installation stage. The booster vacuum chambers have been assembled and baked out in a provisional laboratory exsitu in the ALBA building, and in less than two months (starting from February 2009) all the booster vacuum system was installed inside the tunnel and under vacuum. All the storage ring vacuum chambers have been delivered and ready for installation, several chambers were tested at CELLS (tests include vacuum tests, dimensional check, magnetic permeability tests...etc). All the tools needed for the assembly of the storage ring vacuum chambers have been delivered and tested at CELLS to validate the assembly procedure. Concerning the standard vacuum components; all the gauges and residual gas analyzers were delivered, all the ion pumps and controllers are at CELLS, the NEG pumps, leak detectors, roughing stations and the UHV valves were delivered too. THE BOOSTER SYNCHROTRON

A turn key 100 MeV linac was provided by THALES Communications in order to inject electrons into the booster synchrotron of ALBA [1]. The linac was commissioned in October 2008. This paper reminds the main features of the linac [2] and gives results obtained during the commissioning tests. The energy and emittance measurements have been done on the transfer line designed and installed by CELLS. Specified and measured beam parameters will be compared.

The ALBA pre-injector is a 100MeV Linac provided by THALES Communications as a turn key system. The mechanical installation started in February 2008 and finished in April 2008. Also the installation of the first part of the Linac to Booster Transfer Line and the Linac Diagnostic Line was done simultaneously. The status of the ALBA Linac and Transfer line, the characterization of the Sub-harmonic pre-buncher and the description of the timing system are reported. LINAC SETUP The ALBA Linac consists of a 90 kV DC thermoionic gun, followed by a bunching system designed to reduce the energy spread and the electron losses. This one comprises a Sub-harmonic pre-buncher (500 MHz), a prebuncher (3 GHz) and 22-cells SW Buncher (3 GHz). Two travelling wave constant gradient accelerating sections increase the energy up to 100 MeV. Beam focusing is ensured by shielded solenoids up to the bunching system exit and a triplet of quadrupoles between the two accelerating structures [1]. The Linac will work in single bunch and multi bunch mode, top-up operation is foreseen from the beginning. In table 1 the nominal beam parameters at the Linac exit are summarized.

ALBA will be a third generation synchrotron light facility to be built near Barcelona (Spain). The design phase of ALBA is almost completed and the first components are ready to be ordered. Commissioning of the storage ring is foreseen to start at the end of 2008. The circumference of the storage ring of ALBA is 268.8m and it will be divided into 16 vacuum sections by ultra high vacuum (UHV) gate valves. The vacuum chamber will be made of stainless steel with vertical aperture of 28mm and 72mm width. The vacuum chamber will be connected to an antechamber with a slot of 10mm height. The antechamber will have the crotch absorbers which will absorb the unwanted synchrotron radiation. The pumping will be by sputter ion pumps (SIP), NEG pumps and titanium sublimation pumps (TSP), with an overall pumping speed from SIP of 57,400l/s. This will maintain an average dynamic pressure of around 1×10−9mbar to achieve a beam lifetime >15h at the designed current.

The ALBA pre-injector is a 100MeV Linac provided by THALES Communications as a turn key system. The mechanical installation started in February 2008 and finished in April 2008. Also the installation of the first part of the Linac to Booster Transfer Line and the Linac Diagnostic Line was done simultaneously. The status of the ALBA Linac and Transfer line, the characterization of the Sub-harmonic pre-buncher and the description of the timing system are reported. LINAC SETUP The ALBA Linac consists of a 90 kV DC thermoionic gun, followed by a bunching system designed to reduce the energy spread and the electron losses. This one comprises a Sub-harmonic pre-buncher (500 MHz), a pre- buncher (3 GHz) and 22-cells SW Buncher (3 GHz). Two travelling wave constant gradient accelerating sections increase the energy up to 100 MeV. Beam focusing is ensured by shielded solenoids up to the bunching system exit and a triplet of quadrupoles between the two accelerating structures (1). The Linac will work in single bunch and multi bunch mode, top-up operation is foreseen from the beginning. In table 1 the nominal beam parameters at the Linac exit are summarized.

ALBA is a 3 GeV, 268.8 m storage ring with extended Double Bend Achromat (DBA) structure under construction near Barcelona, Spain. With the design current of 400 mA, a total power of 407 kW is radiated by the circulating beam from the bending magnets. The design of the vacuum system was done by using the concept of the "crotch absorbers" which is used in many modern synchrotron light sources. These absorbers are not only going to absorb the power of the unused radiation but also will allow fast vacuum conditioning. 156 absorbers are need all around the machine in order to guarantee that no radiation will hit the chamber walls, the absorbers are grouped into three types, several design criteria have been studied in order to create our own one which is based on the number of allowed cycles before failure with the concept of the strain values. Finite element analysis (FEA) has been performed to estimate the stress, strain, maximum overall temperature and the maximum cooling temperature for all the types. The results for the critical absorber (type 3) under conservative conditions: max. overall temperature is 312.8degC, max. strain is 0.099 % and max. stress is 112.3 MPa. With this strain, the absorber can withstand up to 1.105 cycles of operation.

ALBA is a 3rd generation light source under construction close to Barcelona, Spain. The lattice chosen consist in a DBA-like structure where most of the vertical focusing takes place in the bending magnets, in order to maximize the space allocated for insertion devices in the lattice and to reduce the emittance. In this case the tunes of the storage ring will be strongly affected by the focusing of the magnetic field of the bending magnet. In existing storage rings with gradient bending magnets it has been realized that the real vertical tune of the machine is slightly different from the theoretical one. In order to avoid this for ALBA we investigated the right modelling of the bending magnet. The corresponding procedures are described within this paper. The parameters of the model are estimated from the field map on the magnet midplane computed with 3D simulations.

ALBA is a 3 generation synchrotron light facility to be built near Barcelona (Spain). The design phase of ALBA is almost completed and the first components (including the vacuum chambers for the storage rings) have been ordered. ALBA consists of a 100 MeV Linac injecting into a 249.6 m circumference booster synchrotron and a 3 GeV, 268.8 m storage ring with DBA structure. The storage ring has a four fold symmetry with 32 bending magnet, 4 long, 12 medium and 8 short straight sections. The stainless steel vacuum chamber (VC) of the storage ring has been designed with the concept of the antechamber where crotch absorbers will be placed. Pumping will be by sputter ion pumps (SIP) and NEG pumps, with an overall pumping speed from SIP of around 57000 l/s. This will maintain an average dynamic pressure of around 1.10 mbar to achieve a beam lifetime >15 hours at the designed current (400mA).

ALBA is a 3 GeV, 400 mA, 3 rd generation Synchrotron Light Source that is in the construction phase in Cerdanyola, near Barcelona, Spain. The RF System will have to provide 3.6 MV of accelerating voltage and restore up to 540 kW of power to the electron beam. For that six RF plants, working at 500 MHz, are foreseen. The RF plants will include several new developments: 1) DAMPY cavity: the normal conducting HOM damped cavity developed by BESSY and based in the EU design; six will be installed. 2) CaCo: A cavity combiner to add the power of two 80 kW IOTs to produce the more than 150 kW needed for each cavity. 3) WATRAX: A waveguide transition to coaxial, specially designed to feed the DAMPY cavities due to the geometrical and cooling constrains. 4) IQ LLRF: The low level RF will be based on the IQ modulation/demodulation technique, both analogue and digital approach are being pursued. This paper describes the status of the storage ring RF System, and reports about these new developments.

The new 3rd generation synchrotron radiation source ALBA to be built nearby Barcelona is planned to start operation in 2009 with several different insertion devices installed in the storage ring either from "day one" or within the first year of operation. The list of high-priority insertion devices includes: 2 planar PPM SmCo invacuum undulators with the period of 21.3 mm; 2 AppleII type PPM NdFeB undulators with periods of 62 mm and 71 mm respectively; 1 superconducting planar wiggler with the period of 31 mm and a maximum field of 2.1 T, and 1 conventional wiggler. The emission of these undulators covers wide spectral range extending from hard X-rays to UV. Pre-design of the IDs was done by ALBA. ALBA will set up a magnetic measurement laboratory for the acceptance tests. The paper will present peculiarities of the magnetic design and calculated maximum-flux spectra.

The new synchrotron radiation source ALBA to be built nearby Barcelona is planned to start operation in 2009. The facility includes a laboratory for magnetic measurements devoted to Insertion Devices (IDs). The foreseen measurement benches include a fixed stretched wire bench aimed to characterise the inhomogeneities of magnet blocks and hence to assist the in-house building of IDs. The design of the system is based both on the ESRF/SOLEIL and BESSY previously existing designs. In this paper we present an exhaustive analysis of error sources and tolerance requirements for that particular design.

A new approach of RF power combination has been developed for the ALBA Storage Ring RF system: a three port high power Cavity Combiner (CaCo). A prototype has been successfully built and tested in Thales Electron Devices, Thonon, France. The final goal is to combine the power of two 80 kW IOTs at 500 MHz, in order to provide a total output power of more than 150 kW. In this paper, a summary of the analytical and simulation analysis of the expected behaviour is given. In basis of that, the decided geometric constrains and the final design configuration chosen for the prototype production are explained. Low power test results and matching, and finally the high power test performances are shown. As a conclusion, the RF system of the ALBA Storage Ring will incorporate the CaCo concept to obtain the needed power per cavity from the combination of two IOTs.

The storage ring ALBA is a 3 generation synchrotron light source under construction in Barcelona (Spain). The facility is based on a 3.0 GeV storage ring of 268.8 m circumference with a beam emittance under 5 nm.rad. Top-up operation is foreseen from day one. The injector complex for ALBA will consist of a 100 MeV linac and a full energy booster. The linac will be a turn-key system which has already been ordered to the industry and delivery is expected in the second half of 2007. The full energy booster will be placed in the same tunnel as the storage ring and will have a circumference of 249.6 m. The lattice of the booster is a modified FODO lattice providing an emittance as low as 9 nm.rad. The magnet system comprises 40 combined magnets and 60 quadrupoles. Chromaticity correction relies on the sextupole component built-in the combined magnets and the quadrupoles. In this paper a description of the injector including the present status of the different components will be given. INTRODUCTION The injector for ALBA will consist of a 100 MeV electron linac followed by a full energy booster up to 3.0 GeV. The booster and the storage ring will share the same tunnel, with a simple transfer line connecting the two rings. LINAC The linac injector for ALBA is a turn key system provided by Thales Communications based on the specifications listed in table 1. It will work in single and multi bunch mode. Figure 1 shows schematically the linac. Table 1: Technical Specifications at the Linac exit Parameter Unit Single Bunch Multi Bunch Pulse Length ns 1 2 to 1024 Charge nC 2 nC 4 nC Norm.Emitt.(1σ) π mm rad ≤ 30 ≤ 30 Energy Spread % ≤ 0.5 (rms) ≤ 0.5 (rms) Rep.Rate Hz 3 to 5 3 to 5 Energy MeV ≥ 100 ≥ 100 The linac consists of a 90 kV dc thermoionic gun, a subharmonic pre-buncher (500 MHz), a pre-buncher (3 GHz) and a 22-cells standing wave buncher (3 GHz). The bunching system is designed to reduce the energy spread and to minimize the losses. Two travelling wave constant gradient accelerating sections increase the energy up to 125 MeV. Two TH2100 pulsed klystrons will feed the accelerating sections, and also the buncher at 3 GHz. The sub-harmonic prebuncher and the pre-buncher at 3 GHz will have an independent RF amplifier. The transmission from the gun to the linac exit has been estimated to be around 80%. Figure 1:ALBA Linac layout Beam focusing is ensured by solenoids up to the bunching section and a triplet of quadrupoles between the two accelerating sections. Beam dynamics simulations have been carried out for single bunch and multi bunch mode with the GPT code [1]. The expected performances are listed in table 2. Table 2: Results from simulations Parameter Unit Single Bunch Multi Bunch Norm.Emitt.(1σ) π mm rad 15 10 Energy Spread % 0.3 (rms) 0.4 (rms)