Planar ultrananocrystalline diamond field emitter in accelerator radio frequency electron injector: Performance metrics

• Published in: Applied physics letters 2014-11, Vol.105 (20)
• Main Authors: Baryshev, Sergey V., Antipov, Sergey, Shao, Jiahang, Jing, Chunguang, Pérez Quintero, Kenneth J., Qiu, Jiaqi, Liu, Wanming, Gai, Wei, Kanareykin, Alexei D., Sumant, Anirudha V.
• Format: Article
• Language: English
• Subjects: Applied physics; Buffer layers; Diamonds; Electron energy; Emission analysis; Emittance; Emitters; Emitters (electron); Equivalence; Field emission; Nitrogen; Performance measurement; Screens
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4901723

A case performance study of a planar field emission cathode (FEC) based on nitrogen-incorporated ultrananocrystalline diamond, (N)UNCD, was carried out in an RF 1.3 GHz electron gun. The FEC was a 100 nm (N)UNCD film grown on a 20 mm diameter stainless steel disk with a Mo buffer layer. At surface gradients 45–65 MV/m, peak currents of 1–80 mA (equivalent to 0.3–25 mA/cm2) were achieved. Imaging with two YAG screens confirmed emission from the (N)UNCD surface with (1) the beam emittance of 1.5 mm × mrad/mm-rms and (2) longitudinal FWHM and rms widths of non-Gaussian energy spread of 0.7% and 11% at an electron energy of 2 MeV. Current stability was tested over the course of 36 × 103 RF pulses (equivalent to 288 × 106 GHz oscillations).