Experimental results of an rf gun and the generation of a multibunch beam

• Published in: Physical review special topics. PRST-AB. Accelerators and beams 2011-06, Vol.14 (6), p.063501, Article 063501
• Main Authors: Deshpande, Abhay, Araki, Sakae, Fukuda, Masafumi, Sakaue, Kazuyuki, Terunuma, Nobuhiro, Urakawa, Junji, Washio, Masakazu
• Format: Article
• Language: English
• Subjects: Electron beams; High energy electrons; Laser beams; Power measurement; Soft x rays; X ray sources; X-rays
• ISSN: 1098-4402; 1098-4402; 2469-9888
• DOI: 10.1103/PhysRevSTAB.14.063501

At the laser undulator compact x-ray source at KEK, our group has designed and built a new rf gun with a larger mode separation of 8.6 MHz and higher Q value than earlier guns. This paper presents details on the design and fabrication, low-power measurements, and tuning procedures followed in the fabrication of the gun cavity. We also give a detailed account of experiments performed with this gun and present measurement results. We have successfully generated 100 bunches per train with a 50 nC charge at 41 MeV and 300 bunches per train with a 160 nC charge at 5 MeV, with low peak-to-peak energy difference. In the future, we plan to go up to a 0.5 nC charge per bunch in an 8000-bunch train at low energy and a 2 nC charge per bunch in a 100-bunch train at high energy. This will make it possible to have higher charge available for laser-beam collisions, thus enabling the generation of high flux soft x rays using the low-energy electron beam and approximately 30 keV x rays using the high-energy electron beam.