In this work the experimental and simulation results of photoemission studies for photoelectrons are presented. The cathode used was a Zn disc having a work function of 4.33 eV. Two different excimer lasers were employed as energy source to apply the photoelectron process: XeCl (308 nm, 10 ns) and KrF (248nm, 23ns). Experimental parameters were the laser fluence (up to 70 mJ/cm2) and the anode-cathode voltage (up to 20 kV). The output current was detected by a resistive shunt having the same value of the characteristic impedance of the system. The best values of global quantum efficiency were approximately 5x10-6 for XeCl and 1x10-4 for KrF laser, while the peaks of the temporal quantum efficiency were 8x10-6 and 1.4x10-4, respectively. The higher efficiency for KrF is ascribed to higher photon energy and to Schottky effect. To enhance the Schottky effect, several electron-beam simulations using OPERA 3-D were carried out to analyze the influence of the geometrical characteristics of the diode.
Temporal quantum efficiency of a micro-structured cathode
NASSISI, Vincenzo;BELLONI, fabio;CARETTO, GIUSEPPE;DORIA, Domenico;LORUSSO, ANTONELLA;MARTINA, Luigi;SICILIANO, MARIA VITTORIA
2006-01-01
Abstract
In this work the experimental and simulation results of photoemission studies for photoelectrons are presented. The cathode used was a Zn disc having a work function of 4.33 eV. Two different excimer lasers were employed as energy source to apply the photoelectron process: XeCl (308 nm, 10 ns) and KrF (248nm, 23ns). Experimental parameters were the laser fluence (up to 70 mJ/cm2) and the anode-cathode voltage (up to 20 kV). The output current was detected by a resistive shunt having the same value of the characteristic impedance of the system. The best values of global quantum efficiency were approximately 5x10-6 for XeCl and 1x10-4 for KrF laser, while the peaks of the temporal quantum efficiency were 8x10-6 and 1.4x10-4, respectively. The higher efficiency for KrF is ascribed to higher photon energy and to Schottky effect. To enhance the Schottky effect, several electron-beam simulations using OPERA 3-D were carried out to analyze the influence of the geometrical characteristics of the diode.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
