Nanomechanical and electrical properties of Nb thin films deposited on Pb substrates by pulsed laser deposition as a new concept photocathode for superconductor cavities
Abstract
We report a design of photocathode, which combines the good photoemissive properties of lead (Pb) and the advantages of superconducting performance of niobium (Nb) when installed into a superconducting radio-frequency gun. The new configuration is obtained by a coating of Nb thin film grown on a disk of Pb via pulsed laser deposition. The central emitting area of Pb is masked by a shield to avoid the Nb deposition. The nanomechanical properties of the Nb film, obtained through nanoindentation measurements, reveal a hardness of 2.8±0.3 GPa, while the study of the electrical resistivity of the film shows the appearance of the superconducting transitions at 9.3 K and 7.3 K for Nb and Pb, respectively, very close to the bulk material values. Additionally, morphological, structural and contamination studies of Nb thin film expose a very low droplet density on the substrate surface, a small polycrystalline orientation of the films and a low contamination level. These results, together with the acceptable Pb quantum efficiency of 2×10−5 found at 266 nm, demonstrate the potentiality of the new concept photocathode.
Autore Pugliese
Tutti gli autori
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Gontad Farina F.J. , Lorusso A. , Panareo M. , Monteduro A.G. , Maruccio G. , Broitman E. , Perrone A.
Titolo volume/Rivista
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT
Anno di pubblicazione
2015
ISSN
0168-9002
ISBN
Non Disponibile
Numero di citazioni Wos
4
Ultimo Aggiornamento Citazioni
28/04/2018
Numero di citazioni Scopus
4
Ultimo Aggiornamento Citazioni
28/04/2018
Settori ERC
Non Disponibile
Codici ASJC
Non Disponibile
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