DIAGNOSTICS DURING THE ALBA BOOSTER COMMISSIONING U. Iriso * , M. Alvarez, R. Mu˜ noz, A. Olmos, and F. P´ erez. CELLS, Ctra. BP-1413 km 3.3, Cerdanyola - 08290 (Barcelona), Spain Abstract The ALBA Booster is a synchrotron designed to acceler- ate electron beams from 100 MeV to 3GeV in a 3Hz cycle. The maximum pulse coming from the ALBA Linac pro- vides 5 mA in the Booster. In order to check all the Booster sub-systems, a Booster pre-commissioning took place dur- ing two weeks in January 2010. This paper presents the Diagnostics elements installed in the ALBA Booster and our experience during the Booster pre-commissioning. INTRODUCTION The ALBA Booster installation finished in November 2009. In order to find out unexpected problems at an early stage, a short Booster pre-commissioning was scheduled for January 2010. It lasted only two weeks so as not to in- terfere excessively with the installation of the Storage Ring and beamlines. The electron beam at the Booster comes from the Linac, which can work in Single and Multi Bunch Mode and was commissioned in Autumn 2008 [1]. The maximum Linac pulse charge is 4 nC, which represents a current of 5 mA at the Booster. The beam is then accelerated in the Booster synchrotron from 100 MeV to 3 GeV in a 3Hz cycle. The Booster consists of a 4-fold symmetry FODO lattice with 40 combined function dipoles [2]. The basic parameters of the ALBA Booster are listed in Table 1. Table 1: Booster design main parameters. Parameter Injection Extraction energy, E [GeV] 0.1 3.0 hor emittance, ｡ x [nm-rad] 150 9 max. current, I [mA] 4.0 circumference, C [m] 249.6 rf freq., f rf [MHz] 499.6 hor / ver tunes, i x /i y 12.42 / 8.37 dipole field, B [T] 0.168 0.873 hor size (at dipole), m x [mm] < 1.8 < 0.3 ver size (at dipole), m y [mm] < 1.8 < 0.10 In order to properly check the Booster synchrotron per- formance, the set of Diagnostics equipment described in Fig. 1 is installed in the machine. Next, we present the Diagnostics elements installed in the Booster and our ex- perience during the pre-commissioning. SCREEN MONITORS The FSOTR is the acronym used to describe the setup that allows to insert either a Fluorescent Screen (YAG:Ce) * ubaldo.iriso@cells.es Figure 1: Linac, LTB, and Booster sketch with the location of the Diagnostics components. or an Optical Transition Radiaton plate. The YAG screen is used for moderate intensity beams, the OTR is devoted for high intensity beams (which typically saturate the YAG emission). The setup includes a manually controled focus and zoom optics got off-the-shelf from EHD-Imaging and a Gigabit Ethernet CCD camera (Basler Scout, 12-bit resolu- tion, 1034x779 pixels, with a square pixel size of 4.65µ m). More information about this setup is shown in [3]. We placed 3 FSOTRs to monitor the beam path along the transfer line from the Linac to Booster (LTB), while 4 more are installed in the Booster to ease the first commissioning goals (first injection, first quadrant, first turn). In order to avoid undesirable image reflections with the YAG screen, it is convenientto make YAG plates optically non-transparent. We did so by attaching a sandblasted plate downstream the YAG. Moreover, reference marks have been added to this plate to provide in-situ calibration and centering position. Figure 2 shows an example of an image taken with the YAG screens. BPM SYSTEM The Booster is equipped with 44 hor and 28 ver correc- tors, and 44 button type BPMs. For economical reasons, it was decided to equip only 28 BPMs with the read out elec- tronics (I-Tech Libera Brilliance). Simulations showed that the horizontal orbit correction with 28 BPMs allows an rms residual of 0.5 mm at BPMs, with a maximum of 4.5 mm BIW10 Preprint -- Edited; preliminary green dot status Final version will appear on JACoW