Articolo in rivista, 2020, ENG, 10.1016/j.nimb.2020.03.024

Emittance evaluation of electron beams produced by photoemission

Velardi, L.; Monteduro, L.; Quarta, G.; Calcagnile, L.; Nassisi, V.; Cicala, G.

Univ Salento, Dept Math & Phys, Lecce, Italy; Ist Nazl Fis Nucl, Sect Lecce, Lecce, Italy; CNR, ISTP, sez. Bari, Italy.

In this work we study the emittance of electron beams generated by three photocathodes (PCs), one based on Cu sample and two on different nanodiamond (ND) layers. The active layers of the ND-based PCs consisted of untreated and hydrogenated ND particles, 250 nm in size, sprayed on alluminum substrates. We show photo-emission measurements performed by a KrF nanosecond excimer laser (lambda = 248 nm) in a vacuum chamber at 10(-6) mbar and the study of emittance. This last was carried out by the pepper pot method using radiochromic films, HD-810 Gafchromic, as sensible detectors for electrons. The study of the emittance was performed by varying the laser spot onto the PC surface and the accelerating voltage (5, 10 and 15 kV). The obtained results showed quantum efficiencies of the ND-based photocathodes higher than that of the reference Cu one, which instead exhibited the lowest value of normalized emittance, 0.2 mm mrad.

Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms (Print) 471 , pp. 100–104

Keywords

Photocathode, Photoemission, Electron beam, Emittance

CNR authors

Velardi Luciano, Cicala Grazia

CNR institutes

ISTP – Istituto per la Scienza e Tecnologia dei Plasmi