PROGETTO SPARC: RISULTATI RECENTI ED ATTIVITA’ PER IL 2012

RECENT ACHIEVEMENTS Mg THIN FILM DEPOSITED ON COPPER CATHODE MAIN RESULTS OBTAINED WITH THE RF GUN OF UCLA no delamination of the film; low dark current (some µA) at 110 MV/m; the emission curve was not linear due to the oxidation of the Mg cathode surface (two-photon process); EDX maps showed that Mg film had not been removed from Cu back-flange.

SURFACE CONTAMINATION

IS YTTRIUM MORE INTERESTING AND SUITED THAN MAGNESIUM? Y WORK FUNCTION IS ABOUT 3 eV. 2° HARMONIC (400 nm~3.1 eV) OF Ti:Sa LASER INSTEAD OF 3° HARMONIC (266 nm~4.7 eV) CAN BE USED; IT MEANS MORE AVAILABLE AND STABLE LASER ENERGY; REDUCED THERMAL EMITTANCE; HIGH REACTIVE WITH RESIDUAL GASES (O2, H2O, H2...).

PHOTOCATHODES BASED ON Y THIN FILM (LASER DIODE @ 406 nm) Just after the laser cleaning with photons @ 406 nm

YTTRIUM QE vs TIME @ 266 nm

SMART SOLUTIONS SURFACE CONTAMINATION CAN BE AVOIDED WITH A VERY THIN MgF2 PROTECTING COATING: ENERGY GAP ~ 12 eV, TRANSPARENT TO THE DRIVE LASER (266nm→ 4.66 eV EVEN BETTER WITH 400 nm → 3.1 eV); PHOTOCATHODES BASED ON LEAD THIN FILMS DEPOSITED BY PLAD TECHNIQUE. CATHODE BASED ON Pb THIN FILM TO BE TESTED IN SUPERCONDUCTING Nb RF CAVITY; AN Mg OR Y BULK CATHODE COVERED BY AN ULTRA-THIN Cu FILM DEPOSITED BY PLD TECHNIQUE.

SMART SOLUTION AN Mg OR Y BULK CATHODE COVERED BY AN ULTRA-THIN Cu FILM DEPOSITED BY PLD TECHNIQUE Mg bulk covered by Cu thin film Mg bulk

Numero Totale Ricercatori 4 FTE: 3.1 Anagrafica 2012   Progetto Speciale: SPARC Responsabile locale: Alessio Perrone 1 Gontad Francisco Associato Borsista INFN CSN V 100 2 D’Anna Emilia Prof. Ordinario 50 3 Perrone Alessio 80 4 De Giorgi Maria Luisa Associato Ricercatore Confermato Numero Totale Ricercatori 4 FTE: 3.1 Tecnici Nome Contratto Qualifica Aff. % Corrado Massimo Tecnico Categoria C Numero Totale Tecnici FTE: 0.5

Preventivo locale di spesa (k€) Missioni interne 6 Missioni estere 9 Consumo 13 Trasporti 1 Manutenzione 2 TOTALE 31

Pubblicazioni recenti collegate al progetto SPARC 1) L. Cultrera, G. Gatti, A. Lorusso, “Photoemission Studies on Yttrium Thin Films”, Rad. Eff. Def. Solids 165:6, 609-617 (2010) 2) A. Lorusso, V. Fasano, K. Lovchinov, A. Perrone, “A parametric study of Y thin films grown by multiple-pulse laser ablation”, J. Vac. Sci. Technol. A 29, 031502-1-5 (2011) 3) A. Lorusso, F. Gontad, A. Perrone, “In-situ and ex-situ investigation of pulsed laser ablation of Y target”, Thin Solid Films (2011) in press 4) A. Lorusso, L. Cultrera, V. Fasano, A. Perrone, “Detailed studies of photocathodes based on Y thin films grown by PLD technique”, Nucl. Instrum. Meth. B (2011) in press 5) F. Gontad, A. Lorusso, A. Perrone, “Detailed mass spectrometric studies during laser ablation of Yttrium target in high vacuum”, Thin Solid Films (2011) in press 6) A. Lorusso, F. Gontad, A. Perrone, “Deposition of MgF2 Thin Films by Pulsed Laser Ablation Technique”, Jpn. J. Appl. Phys. (2011) in press 7) A. Lorusso, F. Gontad, A. Perrone, N. Stankova, “Highlights on photocathodes based on thin films prepared by pulsed laser deposition”, Phys. Rev. ST Accel. Beams (2011) in press 8) A. Lorusso, M. L. De Giorgi, V. Fasano, C. Fotakis, P. Miglietta, E. L. Papadopoulou, A. Perrone, “Detailed studies of yttrium thin films deposited by laser radiation of different pulse durations”, Appl. Surf. Sci. Submitted