Photocathode electron guns are key devices for high quality electron bunches generation. Development of the original photocathode conception — backside illuminated transmissive (for laser beam) photocathode — is going on at the Photo-gun test bench of the Joint Institute for Nuclear Research (JINR). Such cathode has an improved (in comparison with “classic” photocathode) quantum efficiency due to vectorial photoelectric effect. The influence of the diamond-like carbon (DLC) films production technology on quantum efficiency of prepared photocathode has been investigated. DLC films were deposited on silicon substrate and stainless steel mesh by plasma enhanced chemical vapor deposition from gas mixture CH 4 +D z (H z )+Ar and reactive magnetron sputtering using carbon target and gas mixture Ar and Dz(H z ). The concentration of elements in films was determined by Rutherford backscattering spectrometry and Elastic recoil detection analytical methods simultaneously. Raman spectroscopy at visible excitation wavelength was used for I(D)/I(G) ratio determination. Emission properties of the films were investigated, new results concerning extracted charge and quantum efficiency are presented.
Development of the original transmissive photocathode conception is going on in JINR. Results of charge extraction from thin-film diamond-like carbon (DLC) photocathodes are presented. DLC films were prepared using both methods of reactive magnetron sputtering of carbon target in the mixture of Ar and H2(D2) gases and vapor deposition CH4+D2(H2)+Ar.
The influence of deuterated diamond like carbon films technology and properties on quantum efficiency of prepared photocathode has been investigated. Deuterated diamond like carbon films were deposited on silicon substrate and stainless steel mesh by PECVD from gas mixture CH4 and D2 and reactive magnetron sputtering using carbon target and gas mixture Ar and D2. The concentration of elements in films was determined by RBS and ERD. Chemical compositions were analyzed by FT-IR. Raman spectroscopy at visible excitation wavelength was used for I(D)/I(G) ratio determination. The quantum efficiency was calculated from the measured laser energy and the measured cathode charge.
