A. Andrighetto 1, S. Corradetti 1,2, M. Manzolaro 1, L.A.C. Piazza 1, G. Prete 1, D. Scarpa 1,A.Tomaselli 3 J.A. Vasquez 1 SPES Laser Activities IPAC ‘12 – International Particle Accelerator Conference – May 20 th -25 th, 2012 – New Orleans, Louisiana, USA 1 INFN – Laboratori Nazionali di Legnaro, Viale dell’Università, 2 - Legnaro, Padova, ITALY 2 Università di Padova, Dipartimento di Scienze Chimiche, Via Marzolo, 1 – Padova, ITALY 3 Università di Pavia, Facoltà di Ingegneria, Dipartimento di Elettronica, Via Ferrata, 1 – Pavia, ITALY The SPES target mass marker configuration Operating parameters: T= 2000 °C; I oven = 20 – 50 A; P= mbar; Mass marker oven in SPES chamber Aluminum A small tantalum tube (oven) is charged by a calibrated amount of Aluminum, and directly connected to the hot cavity of SPES system. Once heated the oven to 2000 °C the evaporated atoms of Aluminum reach the hot cavity and are ready for ionization. Laser radiation is delivered by a focusing telescope 6 meter far away, and enters in the 3 mm diameter hot cavity, producing ionization. In the initial phase of target prototyping, SPES has developed a SiC target beside UCx. Aluminum comes from (Si,p) nuclear interaction. In order to ionize Aluminum atoms is possible to use a single laser radiation tuned to a specific absorption level around 308 nm wavelength. This particular kind of ionization path can be named two step, one color photoionization, where a second photon ionizes the previously excited atoms. LNL laser setup The laser used for ionization is a broadband excimer laser LPX200 by Lambda Phisyk, which can be charged with XeCl gas and emits laser radiation centered around 308 nm wavelength. Laser radiation is delivered 6 meter far away by a focusing telescope, and enters in the 3 mm diameter hot cavity. 308 nm light interacts with aluminum atoms producing ionization. In order to allows laser radiation to reach the hot cavity, is mandatory to displace the FC and redirect the beam by quadrupole and electrostatic lens, to collect anyway a signal. First step: Resonant: λ =308,2nm Second step: Non – resonant Towards continuum Layout of SPES laser setup in LNL Laser path towards hot cavity versus ion current path to FC LNL laser safety control The safety control system have been designed using self-controlled devices and applying redundancy for achieving a PL e/Cat. 4 (EN/ISO ) and a SIL3 (EN/IEC 62061) safety level. The excimer laser is powered on using five contactors connected in cascade: two of them are controlled by a safety module that monitors the door status using safety magnetic switch; two more ones are controlled by another safety module that monitors an emergency stop button; and the fifth one is controlled by a PLC. The PLC monitors the presence of the protective screens and the status of the ventilation system; controls the access to the laboratory (only allowed after performing a well defined procedure); receive the start command form the user; and indicates the status of the system using acoustic and visual signals. Magnetic switches (on door) Contactors Safety modules Emergency stop push button Scheme of the safety control system.Safety control system devices. LNL front-end laboratory with excimer laser LNL laser ionization results The Faraday Cup (FC) current represents the experimental signal, and it is the experiment result. As results of laser interaction with the atoms in the hot cavity, the collected current signal increases its value and changing are observed even in laser repetition rate variation and in energy pulse sweep. The right figure represents the variation of the faraday cup current produced by the sweep in the frequency of the of the laser pulses, while the left figure is the variation produced by two energy pulses sets. Further analysis will be performed as soon as new Wien filter mass separator will be installed and calibrated. Faraday cup ion current collected performing variation in laser pulse energy, effect direct impacts current value. Faraday cup ion current collected performing variation in laser pulse repetition rate, effect direct impacts current value.